CA2052171A1 - Reloadable canister with replaceable film spool - Google Patents
Reloadable canister with replaceable film spoolInfo
- Publication number
- CA2052171A1 CA2052171A1 CA002052171A CA2052171A CA2052171A1 CA 2052171 A1 CA2052171 A1 CA 2052171A1 CA 002052171 A CA002052171 A CA 002052171A CA 2052171 A CA2052171 A CA 2052171A CA 2052171 A1 CA2052171 A1 CA 2052171A1
- Authority
- CA
- Canada
- Prior art keywords
- film
- canister
- housing
- disk
- core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B27/00—Photographic printing apparatus
- G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
- G03B27/52—Details
- G03B27/58—Baseboards, masking frames, or other holders for the sensitive material
- G03B27/587—Handling photosensitive webs
- G03B27/588—Supply rolls; Cutting arrangements
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B1/00—Film strip handling
- G03B1/60—Measuring or indicating length of the used or unused film; Counting number of exposures
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B17/00—Details of cameras or camera bodies; Accessories therefor
- G03B17/28—Locating light-sensitive material within camera
- G03B17/30—Locating spools or other rotatable holders of coiled film
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B2206/00—Systems for exchange of information between different pieces of apparatus, e.g. for exchanging trimming information, for photo finishing
Abstract
ABSTRACT
A reloadable film canister includes a light-tight enclosure with an aperture for dispensing film therethrough. A spool of film may be loaded into the enclosure, and may be removed when the film is dispensed. In one embodiment of the invention, an encoder (field modulating) disk is included as part of the canister. In another embodiment the encoder disk is affixable to the film spool and loadable with the film spool into the canister. The spool is mountable in the enclosure for rotation therein and for dispensing, at each step of a stepper motor, a predetermined length of film corresponding to the motor's step size. The encoder disk has a plurality of uniformly-spaced, peripherally-arranged segments (elements) detectable by an external detector (sensor), the detector and the stepper motor operating under control of a microprocessor.
Upon rotation of the spool and dispensation of film, the disk provides information, via the detector, to the microprocessor enabling the microprocessor to determine, from the number of motor steps and number of segments detected during rotation, the diameter of the film roll and the length of undispensed film remaining in the canister.
A reloadable film canister includes a light-tight enclosure with an aperture for dispensing film therethrough. A spool of film may be loaded into the enclosure, and may be removed when the film is dispensed. In one embodiment of the invention, an encoder (field modulating) disk is included as part of the canister. In another embodiment the encoder disk is affixable to the film spool and loadable with the film spool into the canister. The spool is mountable in the enclosure for rotation therein and for dispensing, at each step of a stepper motor, a predetermined length of film corresponding to the motor's step size. The encoder disk has a plurality of uniformly-spaced, peripherally-arranged segments (elements) detectable by an external detector (sensor), the detector and the stepper motor operating under control of a microprocessor.
Upon rotation of the spool and dispensation of film, the disk provides information, via the detector, to the microprocessor enabling the microprocessor to determine, from the number of motor steps and number of segments detected during rotation, the diameter of the film roll and the length of undispensed film remaining in the canister.
Description
5~
RE~O~DABLE C~NX~T~ ~IT~ ~PL~C~B~ FI~ 8POOL
Background of the Invention This invention relates generally to ~ilm-monitoring systems and, particlllarly, to a reloadable ~ilm canister with a replaceable spool insertabie into tne anister ~or storing and dispensiny film. The spool and/or canister may be packaged as a unit, or as part of a system for indicating the diameter of ~ilm roll within the canister, for calculating and displaying the amount of ~ilm remaining in the canister, and for indicating the absence of film in the canister.
Accurate knowledge of the amount of film remaining in a film canister is important for camera systems used for computer output microfilm. These camera systems are typically connected either to a host computer, a magnetic tapP drive, or ~ome other ~5 equipment which has stored blocks o~ data whi~h are to be printed on the film by th~ camera system. These data bloc~s vary in size and anywhere from a few feet to several hundred feet of film may be requ~red to print the data. It is important to Xnow the length of film r maining in khe canister before the printing o~
a block of data is started so that there is enough film in the canister to print the block. This will allow the user to load a new full roll of film rather ; ~ than have to splice the film in the middle of a data 3S block.
.
Another reason it is important to accurately know the length of film left becau~e some applications r~quire that a substantial.length of ~ilm be left unprinted at the very end of the ~il~ to ~acilitate threading in~o developer equipment. The accurate knowledge of length of film left allows the camera system to automatically stop when a predetermined amount of film is left and therefore prevent the loss of data due to exposure to light during the threading process.
Determining the amount of film in a fil~ canister has either been ina~curate or inconverient with prior art devices, One device that visually indicates on the side of the canister the amount of film left in the canister incorporates a lever mechanism which contacts the outside of the film roll. This provides only a relative reading with poor accuracy. Ths operator must stop ths camera system and open the film bay area to read the amount of film left. This causes waste by exposing un~ocessed film.
A second device is a meter-only system which allows ~or the display o~ film le~t information on an external device such as a CRT screen. It uses metered feed ro~lers to determine the amount of film removed from a canister having a predetermined starting length of ~ilm. This system simply subtracts the amount of ~ilm metered out from the known starting length. This method, due to accumulatin~ metering errors ! provides relatively poor accuracy as the canister approaches empty. The accuracy of this method also can be seriously degraded b~ "soft" errors of the system (hardware or software) which lose blocks of metering data. Additioral.ly, this method is inoonvenient bec~use canisters are sometimes removed before the film in them is ~sed u~. This requires that the amount of film left in a partially used canister, as determined by the metering system, be written on the canister. The recorded length o~ fil~ remaining in the canister must be manually entered into the system when that canister is inserted or reinserted.
A third device is described in U.S. Patent No.
3,730,453, entitled "~ARLY END TAPE DETECTION,~' issued May 1, 1973, t~ inventors 5.E. Hotchkiss, B.H. Smith, and P.L. Stefko. This device provides a means (an output signal) for identifying when a predetermined position is reached on a tape. Each predetermined - position signifies that a predetermined quantity of tape remains for use. The device detects changes in angular velocities of a tape supply reel as tape is dispensed from the reel, and produces the output signal when the changing angular velocitiPs (axpressed in terms of pulse periods) become egual to a predetermined angular velocity (reference pulse period) when the predetermined position is reached on the tape. This device does not provide ~or determination of the length-of-tape (or film) -- left - without the use of factors such as predetermined pulse - pe iod~, derived from predetermined positions, it does n~t have the capability to provide for continuous readout of the length of film left.
Because it works on the principle of changing angular velocity, this method requires high accuracy in spindlo drive velocity, in the reference frequency, and in operation of the comparator circuitry, and creates problems in applications (such as camera systems) where the medium ttape or film) needs to start and stop frequently, accele;-ating and decelerating through an entire range of angular velocities. Furthermore, this device should not be used for dispensing photographic film because it ~:~.5~
provides no means for shielding the film from a~bient light. Even if ~he device were ~urrounded by a light-tight enclosure, the film, most likely, could not be loaded without risk of exposure unless the lights in the room were turned off. Also, the light source for the photodetector could fog the film.
Summary of the Inventi_n It is an object of this invention to provide a lo film storing and dispensing canister which has a simple and accurate means for indicating the diameter of the film stored therein and means for indicating when a canister is out of film. The film canister consists of an enclosing shell ~ormed of light opaque, non-electrically conductive material with a rotatable spool core or hub, which has film wound on it forming a film roll, mounted inside and has a field modulating disk as part of the spool or mounted to it on one side. The disk would typically be maintained inside the canister to prevent handling damage, but could alternatively be mounted on the outside.
When incorporated i~ a sy~tem for employing the indicating means, which system includes a sensor, a metered feed roller assembly powered by a stepp~~
motor, and a digital compuker (microprocessor), together with the canister, the system can measure the diameter of the film roll from which it calculates and displays the length oP film left in the cani.ster.
The sensor, typically located externally of the canister, detects the completion of each rotation of the spool while a metered feed-roller assembly pulls the film from the canistQr in a precise fashion. This provides a means for measuring the length of fil~
being fed out of the canister for each rota~ion of the spool.
RE~O~DABLE C~NX~T~ ~IT~ ~PL~C~B~ FI~ 8POOL
Background of the Invention This invention relates generally to ~ilm-monitoring systems and, particlllarly, to a reloadable ~ilm canister with a replaceable spool insertabie into tne anister ~or storing and dispensiny film. The spool and/or canister may be packaged as a unit, or as part of a system for indicating the diameter of ~ilm roll within the canister, for calculating and displaying the amount of ~ilm remaining in the canister, and for indicating the absence of film in the canister.
Accurate knowledge of the amount of film remaining in a film canister is important for camera systems used for computer output microfilm. These camera systems are typically connected either to a host computer, a magnetic tapP drive, or ~ome other ~5 equipment which has stored blocks o~ data whi~h are to be printed on the film by th~ camera system. These data bloc~s vary in size and anywhere from a few feet to several hundred feet of film may be requ~red to print the data. It is important to Xnow the length of film r maining in khe canister before the printing o~
a block of data is started so that there is enough film in the canister to print the block. This will allow the user to load a new full roll of film rather ; ~ than have to splice the film in the middle of a data 3S block.
.
Another reason it is important to accurately know the length of film left becau~e some applications r~quire that a substantial.length of ~ilm be left unprinted at the very end of the ~il~ to ~acilitate threading in~o developer equipment. The accurate knowledge of length of film left allows the camera system to automatically stop when a predetermined amount of film is left and therefore prevent the loss of data due to exposure to light during the threading process.
Determining the amount of film in a fil~ canister has either been ina~curate or inconverient with prior art devices, One device that visually indicates on the side of the canister the amount of film left in the canister incorporates a lever mechanism which contacts the outside of the film roll. This provides only a relative reading with poor accuracy. Ths operator must stop ths camera system and open the film bay area to read the amount of film left. This causes waste by exposing un~ocessed film.
A second device is a meter-only system which allows ~or the display o~ film le~t information on an external device such as a CRT screen. It uses metered feed ro~lers to determine the amount of film removed from a canister having a predetermined starting length of ~ilm. This system simply subtracts the amount of ~ilm metered out from the known starting length. This method, due to accumulatin~ metering errors ! provides relatively poor accuracy as the canister approaches empty. The accuracy of this method also can be seriously degraded b~ "soft" errors of the system (hardware or software) which lose blocks of metering data. Additioral.ly, this method is inoonvenient bec~use canisters are sometimes removed before the film in them is ~sed u~. This requires that the amount of film left in a partially used canister, as determined by the metering system, be written on the canister. The recorded length o~ fil~ remaining in the canister must be manually entered into the system when that canister is inserted or reinserted.
A third device is described in U.S. Patent No.
3,730,453, entitled "~ARLY END TAPE DETECTION,~' issued May 1, 1973, t~ inventors 5.E. Hotchkiss, B.H. Smith, and P.L. Stefko. This device provides a means (an output signal) for identifying when a predetermined position is reached on a tape. Each predetermined - position signifies that a predetermined quantity of tape remains for use. The device detects changes in angular velocities of a tape supply reel as tape is dispensed from the reel, and produces the output signal when the changing angular velocitiPs (axpressed in terms of pulse periods) become egual to a predetermined angular velocity (reference pulse period) when the predetermined position is reached on the tape. This device does not provide ~or determination of the length-of-tape (or film) -- left - without the use of factors such as predetermined pulse - pe iod~, derived from predetermined positions, it does n~t have the capability to provide for continuous readout of the length of film left.
Because it works on the principle of changing angular velocity, this method requires high accuracy in spindlo drive velocity, in the reference frequency, and in operation of the comparator circuitry, and creates problems in applications (such as camera systems) where the medium ttape or film) needs to start and stop frequently, accele;-ating and decelerating through an entire range of angular velocities. Furthermore, this device should not be used for dispensing photographic film because it ~:~.5~
provides no means for shielding the film from a~bient light. Even if ~he device were ~urrounded by a light-tight enclosure, the film, most likely, could not be loaded without risk of exposure unless the lights in the room were turned off. Also, the light source for the photodetector could fog the film.
Summary of the Inventi_n It is an object of this invention to provide a lo film storing and dispensing canister which has a simple and accurate means for indicating the diameter of the film stored therein and means for indicating when a canister is out of film. The film canister consists of an enclosing shell ~ormed of light opaque, non-electrically conductive material with a rotatable spool core or hub, which has film wound on it forming a film roll, mounted inside and has a field modulating disk as part of the spool or mounted to it on one side. The disk would typically be maintained inside the canister to prevent handling damage, but could alternatively be mounted on the outside.
When incorporated i~ a sy~tem for employing the indicating means, which system includes a sensor, a metered feed roller assembly powered by a stepp~~
motor, and a digital compuker (microprocessor), together with the canister, the system can measure the diameter of the film roll from which it calculates and displays the length oP film left in the cani.ster.
The sensor, typically located externally of the canister, detects the completion of each rotation of the spool while a metered feed-roller assembly pulls the film from the canistQr in a precise fashion. This provides a means for measuring the length of fil~
being fed out of the canister for each rota~ion of the spool.
2~
The diameter of the ~ilm roll is calculated by a digital computer using the fundamental relati~nship ~etween the diameter and circumference of a circle.
The accuracy of this calculation is limited only by the accuracy of the metering roller and is independent oP feed rate, ti~ing, or canister construction tolerance. ~he use of a digital computer facilitates the determination of a film~out condition and allows for compensation for various factors including the ability to average as many readings as necessary to aliminate the e~fect of random errors. Given the spool core diameter and the film thickn~ss, a digital computer can easily calculate the length of film left on the spool.
The canister employed in the system may be of the disposable type (wherein the film, the film core and, optionally, the field modulating disk, are permanently sealed within the enclosure). This configuration eliminates the need for the user to load the film in the canister (which would require a dark room or glove box).
Alternately, the canister may be ~f the reloadable type, wherein the film package is provided separately from the canister. These are assembled together in a dark envîronment by the user. This configuration allows the canister to be reloaded (with subsequent new film packages as e~ch film package is used up~ and reused.
In one canister/film-package configuration, the field modulating disk would be provided as part of the film package and would be ~ffixed to the core or hub upon which the film is wound. This configuration would be easy to load.
In a second configuration, the disk would form an integral part of the cani~ter, and the film pac~age would be ~eparate. The film package would consist of a core upon which film is wound. The core has at least one keyway or rib or spline, throu~h which or by which to en~age the disk so that they turn ~ogether when ~ilm is dispen~ed.
In a third configuration, the disk is shown as a separate item not permanently affixed to either the core or the canister, but is assembled to th~ core and to the canister, or is attached to the outside of the canister by means of a connecting shaft.
The film package for any of these configurations is provided in a light-tight bag, and a removable label containing the bar code information is affixed to the bag. After the film is transferred from the bag to the reloadable canister (in a dark room or other darX environment), the label is re-affixed to the outside of the reloadable canister.
As ind-cated above, each film package (spool of film) has a core (hub) portion with ~ roll of film wound thereon for dispensing, at each s~ep of the stepper motor, a predetermined increm~ntal length of film corresponding to the ~otorls step size and feed roller d ameter. The disk, which may be affixed to the core or to the canister, has a selected number of detectable segments usable by the computer for determining, from the number of motor steps and the number of segments det2cted during rotation, the diameter of the film roll and the length of undispensed film remaining unusad on the core of the spool.
Brief Description of the Draw~in~s The object~, advantages and features of the invention will be more readily perceived from the following detailed description when read in conjunction with the accompanying drawings, in which:
Fig. 1 is a sectional side view of a disposable fil~ canister constructçd in accordance with the invention;
Fig. 2 is an end sectional view taken along cu~ting plane 2-2 of Fig, l;
Fig. 3 is an end sectional view similar to Fig. 2 of an alternative embodiment of the canister;
Fig. 3A is a partial sectional view similar to Fig. 3 showing an alternative embodiment of the disk and hub configuration;
Fig. 4 i5 a block diagram of the sensing and calculating means of the invention;
Fig. 5 is a logic flow diagram showing how roll diameter and length of film left are determined from input variables;
Fig. 6A is a sectional side view of a reloadable film canister having a repl~ceable spool constructed in accordance with the invention;
Fig. 6B is a sectional front view of the canister and spool shown in Fig. 6A;
Fig. 7A is a sectional top view of an alternative embodiment of a reloadable film canister having a replaceable spool constructed in accordance with the invention;
Fig. 7B is a sectionai side view of the canister and spool shown in Fig. 7A;
Fig. 8 is a diagrammatic illustration of an 3~ encoder disk incorporaked in the spools o~ Fig~. 6A
and 7A: and Figs~ 9A-9D are diagrammatic illustrations showing how the replaceable spools ~f the present invention are journaled in a wall of the canisters of .~ ~ S ~
Figs. 6A, 6B, 7A, and 7B. (For purposes of clarity, the encoder diE;k i~; omitted from Figs. 9A-9C. ) Description of the.Preferred Embodiments With referenGe now to the drawing, and ~ore particularly to Figs. 1 and 2 thereof, there is shown film canister 11 having internal hubs 12 and 13 projecting inwardly from front and back sides 14 and 15 respectively of enclosure shell 13. The rectangular canister or film box is completed by top and bottom walls 16 and 17 and end walls 21 and 22.
In actuality the canister will be ~ormed of two or more segments which are assembled around the film roIl in a light tight shell which is continuous except for the exit slot defined by sealing elements 31.
Further, the canister may have any appropriate shape other than rectangular.
Typically the canister shell would be entirely made of electrically non-conductive material, such as a thermo-plastic, so as to allow the unimpeded ~ transmission of (non-visible) electromagnetic fields : to the field modulating disk. ~owever, this limitation would not apply if the disk is mounted outside the canister. Further, the above limitation is actually only necessary in the immediate vicinity ~ of the location of the external sensor, so that the :~ remainder of the canister could be made of any light opaque material.
Rotatably ~ounted to projections 12 and 13 is ~pool core 23. The mating rounded surfaces of the projections and the spool ~rovide appropriate bearing sur~aces. The film tension during feed and the roll over-travel at the end of a f2ed cycle can ~ypically be controlled by proper selection of hub projection material and diameter without the need for ani external spindle, drive or brake means, or any additional internal friction reducing means. However ~ny of these could be employed where more precise tension is required.
Mounted on one end of spool 23 is field modulating disk 24. This disk i8 shown as being made of metal formed with spaced cutouts 25. The ~etal between the cutouts modifies an electromagnetic field and causes a change of state in a sensor. The ~isk could alternatively be made of a non-conductive substance having conductive elements attached thereto, equivalent to the space between cutouts 25. Disk 24 could be ~ormed intagrally with the spool. Other construction of the disk are also possible. For example, the disk could be made or surfaced with a conductive material with recesses, discontinuities or convolutions that act like cutouts. The important feature is that, rotating with the spool core and film roll at a radius corresponding to where a sensor can be placed and within close proximity to the sensing location are two or more areas of differing interactivity with an external electromagnetic field, th~ transition of which may be detected by a sensor.
It should be noted that for purposes of this invention, only one cutout or sensor interrupt is required by several are shown as they ~ay be use~ul:ly employed to provide an average of multiple readings in a time e~ficient manner3 Cutouts 25 are only as wide as necessary to have a transition from conductive io non-conductive which is detectable. It need only b~ a fraction of the angular width of the disk. Likewise the spaces between the cutouts need only b~ wide enough for the sensor to detect a transition from non-conductive to conductive.
2~
Wound on spool 23 is film roll 26 which is pulled out of the canister as ~ilm 27 through light sealing elements 31 by metered feed-roller assembly 32. The feed-roller assembly comprises rollers 34 and 35~ one of which has a known, accurate circumference and is coupled to stepper motor 43 which is driven by stepper motor drive circuit 4~ (Fig. 4). Positioned externally o~ canister 11 is sensor 36 electrically connected to appropriate calculating mPans through wire 37 (see Fig. 4).
Sensor 36 may be o~ the inductive type which generatPs an oscillating magnetic field. When the conductive areas of disk 24 get close enough to the sensor, the change in magnetic field causes electrical e~dy currents to flow in the disk material. This causes a change, such as a reduction in the amplitude or the frequency, or both, of the oscillating field, which results in a change in output voltage of sensor 36. As film is pulled out of the canister by the metered feed-roller assembly, ~he film roll and field modulating disk are rotated together. The spinning disk alternately presents conductive (or electromagnetically reactive) and non-conductive (or electromagnetically non-rea~tive) areas in proximity with the sensor. Every time there is a transition from non-conductive to conductive areas of the di~k, that is, at the trailing edge ~f a CUtGUt, for example, the sensor is activated and it causes an interrupt of the computer. When the disk continues to rotate so that no conductive areas are near the detector the computer interrupt is reset. Because the canister is made of opaque, non-conductiv~ materials, it provides an effective light seal but does not interfere with the detector field in this situation.
As stated above, the computer uses the length of film metered out by the feed-roller assembly between interrupts to generate a number which is proportional to the diameter of the film roll in the canister.
An alternative embodiment of the film canister is shown in Fig. 3. It functions in a manner identical with the canister. of Figs. 1 and 2 but the hub configuration is different. Core 23 is formed with hub extensions l9 and 20 which extend into canister projections 28 and 29 respectively. The bearing structures permitting relatively fr2e rotation of the core and film roll in the canister are the same or equivalent to those already discussed.
; Fig. 3A shows a disk and hub configuration for the canister which connects the external disk for rotation with the inner spool. Hub 55 is extended : further thxough canister projection 56. A light tight seal is provided between hub 55 and projection 56 by conventional means. Disk 57, configured with se~ments to provide a sensor with signal changes, as before, is secured to hub 55 in some appropriate way for rot~tion therewith. This enables optical position detection for the rotating disk, in addition to other types of detection ~y appropriate sensor means.
The system for calculating th~ diameter of the film roll and the amount of film remaining on the spool is shown in Fig. 4. Computation and control means 41 is typically a microprocessor. The microprocessor logic modules include ~eed rollet controller 4~ which controls the metered feed-roller assembly 32 through stepper driver circuit 44 and stepper motor 43 based on direotives received ~rom camera system controll~r 53. This ~eters a given : amount of film through the meter.~d feed-roller assembly which pulls film from the film roll, causing the f.eld modulating disk to turn. The ~ield ~3.5~
modulating disk causes the rotation sensor to change output state as conductive area transitions pass by.
Interrupt circuit 45 generates a program interrupt signal when a leading (or, altexnatively, a trailing) edge of the sensor output signal is detected. Upon detecting this program interrupt the feed roller controller provides to diameter calculation means 46 the number of steps that the film has been fed since the last interrupt. The diameter of the film enclosed within opaque canister 11 is provided by the following equations:
D - ~ (1) NCF
CR S (2) where D is the diameter of the film roll, CR is the circumference of the film roll and is equal to the length of film metered out for one full rotation of the .~ field modulating disk, N is the numbex of motor steps driven for one rotation of the field modulating disX, 3~ 5 is the ~umber of motor steps for one revslutisn vf the motor, and CF is the circumference of the feed roller.
Calculating element 46 utilizes an algorithm based on Eqs. l and 2 that uses the average of the feed lengths from complete revolutions of each of the multiple slots o~ the field modulating disk. The averaging of multiple revolution data greatly reduces the error caused by random sensing variations. ~he use of only ~ull revolution data in the calculations eliminates errors due to tolerances in field modulating disk construction. The logic used by element 46 to accurately calculate the film roll diameter, the length of film left, and to compensate for roll coast is given in the "Logic For ~oll Diameter and 1ength Left Calculation" section below.
Bar codes are widely available to provide information and film canisters are no exception.
Useful pertinent information about the canister and the film mounted in it is represented on bar code label 81 ~Fig. 4) which is read by conventional bar code reader 82. Bar code evaluation circuit 83, which may be a logic module in the microprocessor, provides to film le K calculator 48 information regarding several canister variables. This is done by analyzing two information fields within the number read from the canister bar code when a film canister is first placed in the camera system. The film type field identifies the core diameter, full film length and nominal film thickness. The unique canister identification field is compared with the identification numbers stored for previously used canisters to determine if the canister has been used before and has a calibrated film thickness value stored. If so, it provides that information to calculate block 48. If not, it provides canister variable information to film thickness calibrate block 84 which i5 enabled for that purpose.
7~
Lot-to-lot variation in film thickness can be a significant source of error in estimating the length of film left (using Equation 4 below) for canist~rs that are nearly full, While this err~r goes to zero 5 as the film is used up, an algorithm is provided which greatly reduces this error based upon knowledge of full canister film length.
Film thickness calibrate block 84 calculates the calibrated film thickness from the full film length and the roll diameter pr4vided by calculate block 46 employing the equation:
t =- ~ (D2-d2) (3) 4Lf where t is the calibrated film thickness, I,f is the full roll film ].ength, and d is the core diameter.
The calibrated film thickness value is automatically stored in non-volatile memory.
Length-of-film left bl.ock 48 uses the roll di2metex provided by block 46, the core diameter provided b~ bar code evaluation block 8~, and the film thickness provided by either bar code evaluator 83 or film thickness calibrate bloc~ 84 to calculate the length of film le~t in the canister using the eguation:
7r (D2--d2) L = 4t ~4) where L is the length of film left.
This langth left information is updated to display ~5.~ 2 d ~_ interface 8~ after each intarrupt, and can ~e displayed on visual display 43, which is typically a CRT. The length lef~ value is stored in non-volatile mamory whenever a canister is removed from the system.
Film out monitor 52 has two methods by which it detects a film-out condition. First, when all the film has ~een unwound from the core, the core and disk stop rotating. The system monitors feed roller controller 42. If more than a predetermined length of film is fed without an interrupt (from the rotation of the field modwlating disk) being detected (indicative that the film has come loose from the core), ~ message is posted to the display interface which causes a film-out message to appear on the visual display. The camera is then stopped at the earliest convenient time by monitor 52.
The second film-out detection method is used, in conjunction with the first method, on those systems where the accuracy of the point where the film comes loose from the core is not a s precise as the film left estimate. In this case film-out monitor 52 monitors the value of the film left on line 51 ~rom calculator 48. When this value approaches a speci~ic point where the film may start to slip on the core, ~ilm monitor 52 takes over the estimation of the length of film left by subtracting the amount of film fed by feed roller controller 42 from the last reliable film left valueO When this estimate of film left goes to zero a film-out message is posted to the display interface and the camera is stoppedL For situations where a substantial unprinted "~ail" length of film is required, the film le~t estimate would be compared to the desired tail length instead of zero.
The first film-out detection method i5 needed in conjunction with the second in order to handle various ~c~
-- 1~
circumstances such as when the operator changes to a dif~erent canister type (with a different core diameter) without notifying the ~ystem (through the bar code) of the change.
Employing the film canister to facilitate diameter sensing in this inve~tion has several significant advantages over known prior art devices.
It provides a simple and inexpensive means for indicating the diameter of the film on a spool in an opague canister. The type of diameter indi~ation used has inherently high accuracy, being insensitive to most manufacturing tolerances within the unit.
Furthermore, it provides a positive film-out indicator, eliminating the need for auxiliary sensors for this purpose.
There are three basic configurations of the system of this invention to estimate the film left using the film canister to facilitate diameter sensing. Each of these configurations has distinct advantages over prior art systems and devices and shows the usefulness of a film canister containing a field modulating disk. The three configurations could be described as having the characteristics of (1):
the complete system described above; (2) the complete system but without a canister bar code label and bar code reader; and ~3) the complete system but without the bar code enhancement and without means for calibrating film thickness.
All three of these systems provide better accuracy than is provided by a lever mechanism incorporated with tha film canister and they avoid opening the camera bay to determine the len~th of film left. Another advantage of the systems of this invention is that they prevent waste vf film. None is lost by unintended ~xposure because there is no need ~5~ d ~
to open the camera bay to check film length. Because the invention determines when the film on the core is at the end, no film is thrown away due to an unknown small amount of film which may remain, which could be the result with prior, less accurate film length determining systems. All of the ~mbodiments of the invention allow for the elimination of a ~eparate "film out" sensor becau~e it is able to detect when the film comes loose from the spool core and because ~f the inherently high ~ilm left accuracy when ths film is nearly expended. All of these e~bodiments also permit removal and replacement of film canisters without writing down or reentering intermediate film-left data.
System (2) above additionally has superior overall film left estimating accuracy than a meter-only system. Because the film thickness calculation uses the predetermined ~ull canister film length, it causes the accuracy of the output for a full ~or ; 20 nearly full) roll to be eguivalent to a similar meter-only system. ~owever, as film is removed from the roll of system (2) the accuracy can actually improve and is superior to a meter only system because in this system there is no accumulation of feed-length errors.
If the calibrated accuracy should be lost for some reason, the accuracy reverts to equivalence to system (3)-System (1~ above eliminates the need by ~he ; operator (in system (2)) to specif~ he type of film and whether or not it is a full roll ~for calibration) when a canis~er is placed in the camera system~ This also allows calibration accuracy to be maintained if a roll is removed and replaced and allows the determination of the amount of film in a canister before it is placed in the camera system by reading ~5~
the canister bar code and the last film-left data stored corresponding to the unique identification field for that canister. While a meter-only system could theoretically also incorporate a canister bar code and bar code reader, it would still provide in~erior film-le~t accuracy, require an additional film-out ~ensor, and would be ~ore susceptible to certain kinds of soft system errors that cause loss of metering data~
It was previously mentioned that the disk could be inside or outsid~ the canister body. If i~ is outside, there are alternative sen ing means which become available. For example, optical sensors could be used with an external disk. The means ~or coupling an external disk to the spool core could be a physical direct connection or a magnetic coupling, among others.
Loqic for Roll Diameter and Lenath Left Calculations The flow diagram of Fig. 5 shows the flow of information between the variables used by calculating element 46 $o give a highly accurate estimate o~ the roll diameter and the length of film left. ~ith respect to Fig. 5, the assumption is made that there are eight encoder slots or predetermined detectable changes around the disk. The use o~ multipla slots all~ws for the averaging of more values sooner after start~up and hence more accuracy and early reduction of random errors. Using eight slots allows for the timely detection of a film out condition and assists in the elimination of coas~ errors by assuring that : for the typical feed cycle of 148 mm any reading received during a coasting condition, due to roll inertia at the end of a feed cycle, will be followed -- 19 --.
by a good reading where film tension is maintained during a feed cycle.
Execution begins when sensor 36 detects a disk slot (step 61) when the disk is rotating. This provides an interrupt from circuit 45 to the system.
The number of feed motor s eps driven since the last detection is obtained from f~ed roller controller 42 in step 62. Steps 63-67 and 71 show the method used to reduce the error caused when a detection of a disk transition occurs after a feed cycle has stopped and the inertia of the roll has caused it to coast some unknown distance. This coast would cause the number of steps to be misleadingly low for this reading ar.d high for the next following raading. Steps 64 and 65 average these two readings and set these readings equal to their averageO Theoretically thes~ values should dif~er by an amount corresponding to the difference in film roll diameters for these tw~
different times. However, ~or typical values of film : 20 thickness and motor characteristics ~steps per revolution) the reading difference would be less than one motor step ~nd not significant. This logic requires that each reading be "bu~fered" or held baok one cycle ~f logic, beginning at step 72, so that each reading can be processed wikh the next reading to correct for coast errors before any further calculations take place.
In step 72 each of the previous eight readings (read in the last eight logic cycles before the present reading) are added together in order to obtain the total number o~ steps for one full revolution of the disk.
In step 73 the last eight revolution totals (including the last) computed in step 72 during the 3S last eight logic cycles are averaged and this average is multiplied by the distance the film moves for one feed mo$or ~tep to obtain an average diameter.
Because there are eight slots in the disk this average of eight revolution totals is obtained in just two rotations of the disk.
The average of the roll is calculated simply by the relationship:
~StepSiæe)*(Sum o~ Last Eight Revolution Totals) AV , ( 5 ) 89r where "Step Size" (equal to CF/S) is the length of film ~ed by the metered feed-roller assembly for one step of the feed-roller controller.
The estimated diameter of the roll at the instant of the last detection is obtained in step 74 by subtracting from this average the of~se~ in diameter caused by one rotation of the disk (two thicknesses of film are removed from the diameter for each rotation~.
~he estimated length ~f film left on the roll i5 easily calculated in step 75 from the roll diameter as explained prev,ously. This method for determiriing film roll diameter and film length reduces the need Por precision in cons~ruction of the field modulating disk and at the same time i filters out random sensing and coast read errors.
Alternative Embodiments Other embodiments of the system may feature ti~e . 30 use of a rel~adable film canister, such as the reloadable film canister 111 shown in Figs. 6A and 6B
~e.g., a 105 millimeter wide film canister), or reloadable canister 112 shown in Figs. 7A and 7B
(e.g., a 16 millimeter wide ~ilm canister).
Canisters 111 and 112 each includes a housing or enclosure 113 comprised of a lid or upper portion 117, 2~
and a mating 4r bottom portion 115 attached to th~ lid portion hy a hinge 119. ~he lid may be opened and closed in the directions shown by arrow 121 permitting easy replacement (pull out, and insertion) of a spool of film in the canister. The enclosure of canister 111 includes two latches 120, 122, and the enclosure of canister 112 includes a latch 124, bridging the edges of both lid and mating portions, for latching ~locking closed) said portions. The e~closure of canister 112 also includes two springs 134, 136, for biasing lid 117 to a cloæed position.
~he spool 123 (Figs. 6A, 68) includes a core (hu~) portion 125 with film 131, and a disk portion 127, whereas th~ spool 126 (Figs. 7A, 7B) includes only a core portion 125 with ~ilm 131; the disk 128 (in Figs. 7A and 7B) is fixed to the canister 11~. A
film 129 is wound on the core 125, forming a film roll 131 wiih a diameter D (Fig. 6A). Disk 127 (~igs. 6A
and 8) and disk 128 (Fig. 7A) each includes a plurality of uni~ormly-spaced peripherally-disposed segments (e.g., eight metallic elements/labels) 133-147 detectable by an electromagnetic sensor 151 (Figs.
6B, 7B) via an opaque plastic window 153. The canisters 111, 112 each includes a pair of guide rollers 155, 157 (Figs. 6A and 7A) for guiding film 159 therethrough to drive rollers of a stepper motor (not shown). The guide rollers direct the film through a circuit~us path, forming a light-tight labyrinth. In the embodiment shown in Fig. 6A, one guide roller 155 is positicned in the top portion or lid 117 o~ the enclosure, and the other guide roller 157 is positioned in the bottom portion of the enclosure. This allows for easy loading and threading of film, and easy access for cleaning the rollers.
As shown in Figs. 6B, 9A and 9B, the spool 123 of film 129 may be. journaled (i.e., mounted ~or rDt~tion) in the canister 111, with the spool fitting into a recess or groove 165 (Fig. 9A), or fitting onto a hub 16i (Figs. 6B and 9B) of the canister. Alternatively, as shown in Figs. 7A, 7B and 9C, the cor~ 125 may form a sleeve 128 for rot~tion on a shaft 169, the shaft being secured to the canister 112 by screws 171, 173.
Also, as shown in Fig. 7B, a flange 130 may be mounted for rotation on the shaft 169, the flange being separated from the encoder disk 128 by a spacer 132.
The ~lange is us~ful in preventing the ~ilm 129 from telescoping (progressively skewing) on the core 125 during rotation o~ the spool. Telescopin~ could cause the film to jam in the canister. In Fig. 7B, the flange 130 is shown to include a projection (finger or screw head) 175 (and an optional projection 177) for mating with and engaging one or more ribs 179 (Fig. 7A) of the core 125 when the film spool is inserted onto the shaft 169 (Figs. 7A and 7B). This flange-core ~projection-rib) structure eliminates thP
need for more complex structures for coupling the film core to the flange and encoder disk.
In view of the above description, it is likely that modifications and improvements will occur to those skilled in the art which are within the scope of the accompanying claims. For example, under Bome circumstances it ~ay ~e possible or desirable for the sensor to be l~cated integrally within the shell.
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and described in the specification certain preferred embodiments, with the understa~ding that the present disclosure is to be considered as an exemplification of the invention; and is n~t intended to limit the invention ~o the speci~ic embodiments illustrated .
The diameter of the ~ilm roll is calculated by a digital computer using the fundamental relati~nship ~etween the diameter and circumference of a circle.
The accuracy of this calculation is limited only by the accuracy of the metering roller and is independent oP feed rate, ti~ing, or canister construction tolerance. ~he use of a digital computer facilitates the determination of a film~out condition and allows for compensation for various factors including the ability to average as many readings as necessary to aliminate the e~fect of random errors. Given the spool core diameter and the film thickn~ss, a digital computer can easily calculate the length of film left on the spool.
The canister employed in the system may be of the disposable type (wherein the film, the film core and, optionally, the field modulating disk, are permanently sealed within the enclosure). This configuration eliminates the need for the user to load the film in the canister (which would require a dark room or glove box).
Alternately, the canister may be ~f the reloadable type, wherein the film package is provided separately from the canister. These are assembled together in a dark envîronment by the user. This configuration allows the canister to be reloaded (with subsequent new film packages as e~ch film package is used up~ and reused.
In one canister/film-package configuration, the field modulating disk would be provided as part of the film package and would be ~ffixed to the core or hub upon which the film is wound. This configuration would be easy to load.
In a second configuration, the disk would form an integral part of the cani~ter, and the film pac~age would be ~eparate. The film package would consist of a core upon which film is wound. The core has at least one keyway or rib or spline, throu~h which or by which to en~age the disk so that they turn ~ogether when ~ilm is dispen~ed.
In a third configuration, the disk is shown as a separate item not permanently affixed to either the core or the canister, but is assembled to th~ core and to the canister, or is attached to the outside of the canister by means of a connecting shaft.
The film package for any of these configurations is provided in a light-tight bag, and a removable label containing the bar code information is affixed to the bag. After the film is transferred from the bag to the reloadable canister (in a dark room or other darX environment), the label is re-affixed to the outside of the reloadable canister.
As ind-cated above, each film package (spool of film) has a core (hub) portion with ~ roll of film wound thereon for dispensing, at each s~ep of the stepper motor, a predetermined increm~ntal length of film corresponding to the ~otorls step size and feed roller d ameter. The disk, which may be affixed to the core or to the canister, has a selected number of detectable segments usable by the computer for determining, from the number of motor steps and the number of segments det2cted during rotation, the diameter of the film roll and the length of undispensed film remaining unusad on the core of the spool.
Brief Description of the Draw~in~s The object~, advantages and features of the invention will be more readily perceived from the following detailed description when read in conjunction with the accompanying drawings, in which:
Fig. 1 is a sectional side view of a disposable fil~ canister constructçd in accordance with the invention;
Fig. 2 is an end sectional view taken along cu~ting plane 2-2 of Fig, l;
Fig. 3 is an end sectional view similar to Fig. 2 of an alternative embodiment of the canister;
Fig. 3A is a partial sectional view similar to Fig. 3 showing an alternative embodiment of the disk and hub configuration;
Fig. 4 i5 a block diagram of the sensing and calculating means of the invention;
Fig. 5 is a logic flow diagram showing how roll diameter and length of film left are determined from input variables;
Fig. 6A is a sectional side view of a reloadable film canister having a repl~ceable spool constructed in accordance with the invention;
Fig. 6B is a sectional front view of the canister and spool shown in Fig. 6A;
Fig. 7A is a sectional top view of an alternative embodiment of a reloadable film canister having a replaceable spool constructed in accordance with the invention;
Fig. 7B is a sectionai side view of the canister and spool shown in Fig. 7A;
Fig. 8 is a diagrammatic illustration of an 3~ encoder disk incorporaked in the spools o~ Fig~. 6A
and 7A: and Figs~ 9A-9D are diagrammatic illustrations showing how the replaceable spools ~f the present invention are journaled in a wall of the canisters of .~ ~ S ~
Figs. 6A, 6B, 7A, and 7B. (For purposes of clarity, the encoder diE;k i~; omitted from Figs. 9A-9C. ) Description of the.Preferred Embodiments With referenGe now to the drawing, and ~ore particularly to Figs. 1 and 2 thereof, there is shown film canister 11 having internal hubs 12 and 13 projecting inwardly from front and back sides 14 and 15 respectively of enclosure shell 13. The rectangular canister or film box is completed by top and bottom walls 16 and 17 and end walls 21 and 22.
In actuality the canister will be ~ormed of two or more segments which are assembled around the film roIl in a light tight shell which is continuous except for the exit slot defined by sealing elements 31.
Further, the canister may have any appropriate shape other than rectangular.
Typically the canister shell would be entirely made of electrically non-conductive material, such as a thermo-plastic, so as to allow the unimpeded ~ transmission of (non-visible) electromagnetic fields : to the field modulating disk. ~owever, this limitation would not apply if the disk is mounted outside the canister. Further, the above limitation is actually only necessary in the immediate vicinity ~ of the location of the external sensor, so that the :~ remainder of the canister could be made of any light opaque material.
Rotatably ~ounted to projections 12 and 13 is ~pool core 23. The mating rounded surfaces of the projections and the spool ~rovide appropriate bearing sur~aces. The film tension during feed and the roll over-travel at the end of a f2ed cycle can ~ypically be controlled by proper selection of hub projection material and diameter without the need for ani external spindle, drive or brake means, or any additional internal friction reducing means. However ~ny of these could be employed where more precise tension is required.
Mounted on one end of spool 23 is field modulating disk 24. This disk i8 shown as being made of metal formed with spaced cutouts 25. The ~etal between the cutouts modifies an electromagnetic field and causes a change of state in a sensor. The ~isk could alternatively be made of a non-conductive substance having conductive elements attached thereto, equivalent to the space between cutouts 25. Disk 24 could be ~ormed intagrally with the spool. Other construction of the disk are also possible. For example, the disk could be made or surfaced with a conductive material with recesses, discontinuities or convolutions that act like cutouts. The important feature is that, rotating with the spool core and film roll at a radius corresponding to where a sensor can be placed and within close proximity to the sensing location are two or more areas of differing interactivity with an external electromagnetic field, th~ transition of which may be detected by a sensor.
It should be noted that for purposes of this invention, only one cutout or sensor interrupt is required by several are shown as they ~ay be use~ul:ly employed to provide an average of multiple readings in a time e~ficient manner3 Cutouts 25 are only as wide as necessary to have a transition from conductive io non-conductive which is detectable. It need only b~ a fraction of the angular width of the disk. Likewise the spaces between the cutouts need only b~ wide enough for the sensor to detect a transition from non-conductive to conductive.
2~
Wound on spool 23 is film roll 26 which is pulled out of the canister as ~ilm 27 through light sealing elements 31 by metered feed-roller assembly 32. The feed-roller assembly comprises rollers 34 and 35~ one of which has a known, accurate circumference and is coupled to stepper motor 43 which is driven by stepper motor drive circuit 4~ (Fig. 4). Positioned externally o~ canister 11 is sensor 36 electrically connected to appropriate calculating mPans through wire 37 (see Fig. 4).
Sensor 36 may be o~ the inductive type which generatPs an oscillating magnetic field. When the conductive areas of disk 24 get close enough to the sensor, the change in magnetic field causes electrical e~dy currents to flow in the disk material. This causes a change, such as a reduction in the amplitude or the frequency, or both, of the oscillating field, which results in a change in output voltage of sensor 36. As film is pulled out of the canister by the metered feed-roller assembly, ~he film roll and field modulating disk are rotated together. The spinning disk alternately presents conductive (or electromagnetically reactive) and non-conductive (or electromagnetically non-rea~tive) areas in proximity with the sensor. Every time there is a transition from non-conductive to conductive areas of the di~k, that is, at the trailing edge ~f a CUtGUt, for example, the sensor is activated and it causes an interrupt of the computer. When the disk continues to rotate so that no conductive areas are near the detector the computer interrupt is reset. Because the canister is made of opaque, non-conductiv~ materials, it provides an effective light seal but does not interfere with the detector field in this situation.
As stated above, the computer uses the length of film metered out by the feed-roller assembly between interrupts to generate a number which is proportional to the diameter of the film roll in the canister.
An alternative embodiment of the film canister is shown in Fig. 3. It functions in a manner identical with the canister. of Figs. 1 and 2 but the hub configuration is different. Core 23 is formed with hub extensions l9 and 20 which extend into canister projections 28 and 29 respectively. The bearing structures permitting relatively fr2e rotation of the core and film roll in the canister are the same or equivalent to those already discussed.
; Fig. 3A shows a disk and hub configuration for the canister which connects the external disk for rotation with the inner spool. Hub 55 is extended : further thxough canister projection 56. A light tight seal is provided between hub 55 and projection 56 by conventional means. Disk 57, configured with se~ments to provide a sensor with signal changes, as before, is secured to hub 55 in some appropriate way for rot~tion therewith. This enables optical position detection for the rotating disk, in addition to other types of detection ~y appropriate sensor means.
The system for calculating th~ diameter of the film roll and the amount of film remaining on the spool is shown in Fig. 4. Computation and control means 41 is typically a microprocessor. The microprocessor logic modules include ~eed rollet controller 4~ which controls the metered feed-roller assembly 32 through stepper driver circuit 44 and stepper motor 43 based on direotives received ~rom camera system controll~r 53. This ~eters a given : amount of film through the meter.~d feed-roller assembly which pulls film from the film roll, causing the f.eld modulating disk to turn. The ~ield ~3.5~
modulating disk causes the rotation sensor to change output state as conductive area transitions pass by.
Interrupt circuit 45 generates a program interrupt signal when a leading (or, altexnatively, a trailing) edge of the sensor output signal is detected. Upon detecting this program interrupt the feed roller controller provides to diameter calculation means 46 the number of steps that the film has been fed since the last interrupt. The diameter of the film enclosed within opaque canister 11 is provided by the following equations:
D - ~ (1) NCF
CR S (2) where D is the diameter of the film roll, CR is the circumference of the film roll and is equal to the length of film metered out for one full rotation of the .~ field modulating disk, N is the numbex of motor steps driven for one rotation of the field modulating disX, 3~ 5 is the ~umber of motor steps for one revslutisn vf the motor, and CF is the circumference of the feed roller.
Calculating element 46 utilizes an algorithm based on Eqs. l and 2 that uses the average of the feed lengths from complete revolutions of each of the multiple slots o~ the field modulating disk. The averaging of multiple revolution data greatly reduces the error caused by random sensing variations. ~he use of only ~ull revolution data in the calculations eliminates errors due to tolerances in field modulating disk construction. The logic used by element 46 to accurately calculate the film roll diameter, the length of film left, and to compensate for roll coast is given in the "Logic For ~oll Diameter and 1ength Left Calculation" section below.
Bar codes are widely available to provide information and film canisters are no exception.
Useful pertinent information about the canister and the film mounted in it is represented on bar code label 81 ~Fig. 4) which is read by conventional bar code reader 82. Bar code evaluation circuit 83, which may be a logic module in the microprocessor, provides to film le K calculator 48 information regarding several canister variables. This is done by analyzing two information fields within the number read from the canister bar code when a film canister is first placed in the camera system. The film type field identifies the core diameter, full film length and nominal film thickness. The unique canister identification field is compared with the identification numbers stored for previously used canisters to determine if the canister has been used before and has a calibrated film thickness value stored. If so, it provides that information to calculate block 48. If not, it provides canister variable information to film thickness calibrate block 84 which i5 enabled for that purpose.
7~
Lot-to-lot variation in film thickness can be a significant source of error in estimating the length of film left (using Equation 4 below) for canist~rs that are nearly full, While this err~r goes to zero 5 as the film is used up, an algorithm is provided which greatly reduces this error based upon knowledge of full canister film length.
Film thickness calibrate block 84 calculates the calibrated film thickness from the full film length and the roll diameter pr4vided by calculate block 46 employing the equation:
t =- ~ (D2-d2) (3) 4Lf where t is the calibrated film thickness, I,f is the full roll film ].ength, and d is the core diameter.
The calibrated film thickness value is automatically stored in non-volatile memory.
Length-of-film left bl.ock 48 uses the roll di2metex provided by block 46, the core diameter provided b~ bar code evaluation block 8~, and the film thickness provided by either bar code evaluator 83 or film thickness calibrate bloc~ 84 to calculate the length of film le~t in the canister using the eguation:
7r (D2--d2) L = 4t ~4) where L is the length of film left.
This langth left information is updated to display ~5.~ 2 d ~_ interface 8~ after each intarrupt, and can ~e displayed on visual display 43, which is typically a CRT. The length lef~ value is stored in non-volatile mamory whenever a canister is removed from the system.
Film out monitor 52 has two methods by which it detects a film-out condition. First, when all the film has ~een unwound from the core, the core and disk stop rotating. The system monitors feed roller controller 42. If more than a predetermined length of film is fed without an interrupt (from the rotation of the field modwlating disk) being detected (indicative that the film has come loose from the core), ~ message is posted to the display interface which causes a film-out message to appear on the visual display. The camera is then stopped at the earliest convenient time by monitor 52.
The second film-out detection method is used, in conjunction with the first method, on those systems where the accuracy of the point where the film comes loose from the core is not a s precise as the film left estimate. In this case film-out monitor 52 monitors the value of the film left on line 51 ~rom calculator 48. When this value approaches a speci~ic point where the film may start to slip on the core, ~ilm monitor 52 takes over the estimation of the length of film left by subtracting the amount of film fed by feed roller controller 42 from the last reliable film left valueO When this estimate of film left goes to zero a film-out message is posted to the display interface and the camera is stoppedL For situations where a substantial unprinted "~ail" length of film is required, the film le~t estimate would be compared to the desired tail length instead of zero.
The first film-out detection method i5 needed in conjunction with the second in order to handle various ~c~
-- 1~
circumstances such as when the operator changes to a dif~erent canister type (with a different core diameter) without notifying the ~ystem (through the bar code) of the change.
Employing the film canister to facilitate diameter sensing in this inve~tion has several significant advantages over known prior art devices.
It provides a simple and inexpensive means for indicating the diameter of the film on a spool in an opague canister. The type of diameter indi~ation used has inherently high accuracy, being insensitive to most manufacturing tolerances within the unit.
Furthermore, it provides a positive film-out indicator, eliminating the need for auxiliary sensors for this purpose.
There are three basic configurations of the system of this invention to estimate the film left using the film canister to facilitate diameter sensing. Each of these configurations has distinct advantages over prior art systems and devices and shows the usefulness of a film canister containing a field modulating disk. The three configurations could be described as having the characteristics of (1):
the complete system described above; (2) the complete system but without a canister bar code label and bar code reader; and ~3) the complete system but without the bar code enhancement and without means for calibrating film thickness.
All three of these systems provide better accuracy than is provided by a lever mechanism incorporated with tha film canister and they avoid opening the camera bay to determine the len~th of film left. Another advantage of the systems of this invention is that they prevent waste vf film. None is lost by unintended ~xposure because there is no need ~5~ d ~
to open the camera bay to check film length. Because the invention determines when the film on the core is at the end, no film is thrown away due to an unknown small amount of film which may remain, which could be the result with prior, less accurate film length determining systems. All of the ~mbodiments of the invention allow for the elimination of a ~eparate "film out" sensor becau~e it is able to detect when the film comes loose from the spool core and because ~f the inherently high ~ilm left accuracy when ths film is nearly expended. All of these e~bodiments also permit removal and replacement of film canisters without writing down or reentering intermediate film-left data.
System (2) above additionally has superior overall film left estimating accuracy than a meter-only system. Because the film thickness calculation uses the predetermined ~ull canister film length, it causes the accuracy of the output for a full ~or ; 20 nearly full) roll to be eguivalent to a similar meter-only system. ~owever, as film is removed from the roll of system (2) the accuracy can actually improve and is superior to a meter only system because in this system there is no accumulation of feed-length errors.
If the calibrated accuracy should be lost for some reason, the accuracy reverts to equivalence to system (3)-System (1~ above eliminates the need by ~he ; operator (in system (2)) to specif~ he type of film and whether or not it is a full roll ~for calibration) when a canis~er is placed in the camera system~ This also allows calibration accuracy to be maintained if a roll is removed and replaced and allows the determination of the amount of film in a canister before it is placed in the camera system by reading ~5~
the canister bar code and the last film-left data stored corresponding to the unique identification field for that canister. While a meter-only system could theoretically also incorporate a canister bar code and bar code reader, it would still provide in~erior film-le~t accuracy, require an additional film-out ~ensor, and would be ~ore susceptible to certain kinds of soft system errors that cause loss of metering data~
It was previously mentioned that the disk could be inside or outsid~ the canister body. If i~ is outside, there are alternative sen ing means which become available. For example, optical sensors could be used with an external disk. The means ~or coupling an external disk to the spool core could be a physical direct connection or a magnetic coupling, among others.
Loqic for Roll Diameter and Lenath Left Calculations The flow diagram of Fig. 5 shows the flow of information between the variables used by calculating element 46 $o give a highly accurate estimate o~ the roll diameter and the length of film left. ~ith respect to Fig. 5, the assumption is made that there are eight encoder slots or predetermined detectable changes around the disk. The use o~ multipla slots all~ws for the averaging of more values sooner after start~up and hence more accuracy and early reduction of random errors. Using eight slots allows for the timely detection of a film out condition and assists in the elimination of coas~ errors by assuring that : for the typical feed cycle of 148 mm any reading received during a coasting condition, due to roll inertia at the end of a feed cycle, will be followed -- 19 --.
by a good reading where film tension is maintained during a feed cycle.
Execution begins when sensor 36 detects a disk slot (step 61) when the disk is rotating. This provides an interrupt from circuit 45 to the system.
The number of feed motor s eps driven since the last detection is obtained from f~ed roller controller 42 in step 62. Steps 63-67 and 71 show the method used to reduce the error caused when a detection of a disk transition occurs after a feed cycle has stopped and the inertia of the roll has caused it to coast some unknown distance. This coast would cause the number of steps to be misleadingly low for this reading ar.d high for the next following raading. Steps 64 and 65 average these two readings and set these readings equal to their averageO Theoretically thes~ values should dif~er by an amount corresponding to the difference in film roll diameters for these tw~
different times. However, ~or typical values of film : 20 thickness and motor characteristics ~steps per revolution) the reading difference would be less than one motor step ~nd not significant. This logic requires that each reading be "bu~fered" or held baok one cycle ~f logic, beginning at step 72, so that each reading can be processed wikh the next reading to correct for coast errors before any further calculations take place.
In step 72 each of the previous eight readings (read in the last eight logic cycles before the present reading) are added together in order to obtain the total number o~ steps for one full revolution of the disk.
In step 73 the last eight revolution totals (including the last) computed in step 72 during the 3S last eight logic cycles are averaged and this average is multiplied by the distance the film moves for one feed mo$or ~tep to obtain an average diameter.
Because there are eight slots in the disk this average of eight revolution totals is obtained in just two rotations of the disk.
The average of the roll is calculated simply by the relationship:
~StepSiæe)*(Sum o~ Last Eight Revolution Totals) AV , ( 5 ) 89r where "Step Size" (equal to CF/S) is the length of film ~ed by the metered feed-roller assembly for one step of the feed-roller controller.
The estimated diameter of the roll at the instant of the last detection is obtained in step 74 by subtracting from this average the of~se~ in diameter caused by one rotation of the disk (two thicknesses of film are removed from the diameter for each rotation~.
~he estimated length ~f film left on the roll i5 easily calculated in step 75 from the roll diameter as explained prev,ously. This method for determiriing film roll diameter and film length reduces the need Por precision in cons~ruction of the field modulating disk and at the same time i filters out random sensing and coast read errors.
Alternative Embodiments Other embodiments of the system may feature ti~e . 30 use of a rel~adable film canister, such as the reloadable film canister 111 shown in Figs. 6A and 6B
~e.g., a 105 millimeter wide film canister), or reloadable canister 112 shown in Figs. 7A and 7B
(e.g., a 16 millimeter wide ~ilm canister).
Canisters 111 and 112 each includes a housing or enclosure 113 comprised of a lid or upper portion 117, 2~
and a mating 4r bottom portion 115 attached to th~ lid portion hy a hinge 119. ~he lid may be opened and closed in the directions shown by arrow 121 permitting easy replacement (pull out, and insertion) of a spool of film in the canister. The enclosure of canister 111 includes two latches 120, 122, and the enclosure of canister 112 includes a latch 124, bridging the edges of both lid and mating portions, for latching ~locking closed) said portions. The e~closure of canister 112 also includes two springs 134, 136, for biasing lid 117 to a cloæed position.
~he spool 123 (Figs. 6A, 68) includes a core (hu~) portion 125 with film 131, and a disk portion 127, whereas th~ spool 126 (Figs. 7A, 7B) includes only a core portion 125 with ~ilm 131; the disk 128 (in Figs. 7A and 7B) is fixed to the canister 11~. A
film 129 is wound on the core 125, forming a film roll 131 wiih a diameter D (Fig. 6A). Disk 127 (~igs. 6A
and 8) and disk 128 (Fig. 7A) each includes a plurality of uni~ormly-spaced peripherally-disposed segments (e.g., eight metallic elements/labels) 133-147 detectable by an electromagnetic sensor 151 (Figs.
6B, 7B) via an opaque plastic window 153. The canisters 111, 112 each includes a pair of guide rollers 155, 157 (Figs. 6A and 7A) for guiding film 159 therethrough to drive rollers of a stepper motor (not shown). The guide rollers direct the film through a circuit~us path, forming a light-tight labyrinth. In the embodiment shown in Fig. 6A, one guide roller 155 is positicned in the top portion or lid 117 o~ the enclosure, and the other guide roller 157 is positioned in the bottom portion of the enclosure. This allows for easy loading and threading of film, and easy access for cleaning the rollers.
As shown in Figs. 6B, 9A and 9B, the spool 123 of film 129 may be. journaled (i.e., mounted ~or rDt~tion) in the canister 111, with the spool fitting into a recess or groove 165 (Fig. 9A), or fitting onto a hub 16i (Figs. 6B and 9B) of the canister. Alternatively, as shown in Figs. 7A, 7B and 9C, the cor~ 125 may form a sleeve 128 for rot~tion on a shaft 169, the shaft being secured to the canister 112 by screws 171, 173.
Also, as shown in Fig. 7B, a flange 130 may be mounted for rotation on the shaft 169, the flange being separated from the encoder disk 128 by a spacer 132.
The ~lange is us~ful in preventing the ~ilm 129 from telescoping (progressively skewing) on the core 125 during rotation o~ the spool. Telescopin~ could cause the film to jam in the canister. In Fig. 7B, the flange 130 is shown to include a projection (finger or screw head) 175 (and an optional projection 177) for mating with and engaging one or more ribs 179 (Fig. 7A) of the core 125 when the film spool is inserted onto the shaft 169 (Figs. 7A and 7B). This flange-core ~projection-rib) structure eliminates thP
need for more complex structures for coupling the film core to the flange and encoder disk.
In view of the above description, it is likely that modifications and improvements will occur to those skilled in the art which are within the scope of the accompanying claims. For example, under Bome circumstances it ~ay ~e possible or desirable for the sensor to be l~cated integrally within the shell.
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and described in the specification certain preferred embodiments, with the understa~ding that the present disclosure is to be considered as an exemplification of the invention; and is n~t intended to limit the invention ~o the speci~ic embodiments illustrated .
Claims (11)
1. A reloadable film canister comprising:
a light-tight housing defining an interior film receiving region;
support means carried by said housing;
an encoder disk; and a film carrying core removably insertable into said housing and carried on said support means wherein said core is coupled to said disk within said housing, at least when said core is so inserted, with said disk being usable to detect a rotation of said core.
a light-tight housing defining an interior film receiving region;
support means carried by said housing;
an encoder disk; and a film carrying core removably insertable into said housing and carried on said support means wherein said core is coupled to said disk within said housing, at least when said core is so inserted, with said disk being usable to detect a rotation of said core.
2. A canister as in claim 1 wherein said disk is rotatably carried adjacent to said region within said housing.
3. A canister as in claim 1 wherein said disk is fixedly attached to said core and insertable into said housing with said core.
4. A system usable with a reloadable film canister as in claim 1 for determining the length of film remaining in the canister, said system comprising:
sensor means, located outside of said housing, for detecting rotation of said core and said disk and for providing a signal indicative of the position of said disk;
film feed-metering means for precisely extracting a length of film from said housing; and computation and control means for providing a feed length control signal to said film feed-metering means, for determining, from said disk position signal in conjunction with said feed length control signal, the diameter of the film roll, and the length of film remaining in said housing and for determining when said housing is empty.
sensor means, located outside of said housing, for detecting rotation of said core and said disk and for providing a signal indicative of the position of said disk;
film feed-metering means for precisely extracting a length of film from said housing; and computation and control means for providing a feed length control signal to said film feed-metering means, for determining, from said disk position signal in conjunction with said feed length control signal, the diameter of the film roll, and the length of film remaining in said housing and for determining when said housing is empty.
5. A system as in claim 4, wherein said film feed-metering means includes a stepper motor coupled to a roller which drives the film from said housing, said roller having a calibrated circumferential length whereby each full rotation of said roller, or partial rotation corresponding to a discrete number of steps of said stepper motor, provides a precise value of the length of film fed from said housing.
6. A system as in claim 4 further including visual display means for displaying the length of film remaining in said housing.
7. A system as in claim 4 wherein said computation and control means includes:
film-out detector means for determining when the film on said spool has been expended, said film detector means generating a film out signal indicative of the end of available film in said housing; and means responsive to said film out signal for stopping use of the film from said housing.
film-out detector means for determining when the film on said spool has been expended, said film detector means generating a film out signal indicative of the end of available film in said housing; and means responsive to said film out signal for stopping use of the film from said housing.
8. A system usable with a reloadable canister as in claim 4 including:
a coded label on said housing, said label representing information regarding the film in said housing including full length and nominal thickness of the film and the diameter of said core, said coded label having a different identification number for each housing, a label reader:
code evaluation circuit means; and means for coupling said code evaluation circuit to said computation and control means to facilitate determination of film roll diameter and length of film remaining on said core.
a coded label on said housing, said label representing information regarding the film in said housing including full length and nominal thickness of the film and the diameter of said core, said coded label having a different identification number for each housing, a label reader:
code evaluation circuit means; and means for coupling said code evaluation circuit to said computation and control means to facilitate determination of film roll diameter and length of film remaining on said core.
9. A method for determining the length of film mounted on a core in a reloadable canister as in claim 1 comprising the steps of:
coupling the disk to the core, the disk having spaced detectable elements thereon and rotating with the core;
determining the length of film fed out of the housing while sensing the rotation of the disk;
providing a signal indicative of the position of the disk;
calculating the diameter of the film on the core in the housing; and calculating the length of film left on the core in the housing.
coupling the disk to the core, the disk having spaced detectable elements thereon and rotating with the core;
determining the length of film fed out of the housing while sensing the rotation of the disk;
providing a signal indicative of the position of the disk;
calculating the diameter of the film on the core in the housing; and calculating the length of film left on the core in the housing.
10. A method as in claim 9 including the further steps of:
determining when the film in the housing has been expended; and generating a signal indicative that the film has been expended.
determining when the film in the housing has been expended; and generating a signal indicative that the film has been expended.
11. A method as in claim 9 including the further steps for:
reading coded information from the housing regarding full length and nominal thickness of the film therein, the diameter of the core, and the canister identification number;
evaluating the coded information;
providing a signal representative of the evaluated information.
reading coded information from the housing regarding full length and nominal thickness of the film therein, the diameter of the core, and the canister identification number;
evaluating the coded information;
providing a signal representative of the evaluated information.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US590,470 | 1990-09-27 | ||
| US07/590,470 US5247323A (en) | 1990-03-29 | 1990-09-27 | Reloadable canister with replaceable film spool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2052171A1 true CA2052171A1 (en) | 1992-03-28 |
Family
ID=24362397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002052171A Abandoned CA2052171A1 (en) | 1990-09-27 | 1991-09-24 | Reloadable canister with replaceable film spool |
Country Status (7)
| Country | Link |
|---|---|
| US (2) | US5247323A (en) |
| EP (1) | EP0504369B1 (en) |
| JP (1) | JP2744845B2 (en) |
| AT (1) | ATE143737T1 (en) |
| CA (1) | CA2052171A1 (en) |
| DE (1) | DE69122492T2 (en) |
| WO (1) | WO1992006404A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809358A (en) * | 1990-03-29 | 1998-09-15 | Anacomp, Inc. | Reloadable canister with replaceable film spool |
| JP2890014B2 (en) * | 1992-11-19 | 1999-05-10 | 富士写真フイルム株式会社 | Magnetic tape winding device |
| CA2182447C (en) * | 1995-08-07 | 2005-06-21 | Kevin A. Fitzgerald | Reloadable film canister system |
| US5659833A (en) * | 1995-10-30 | 1997-08-19 | Anacomp, Inc. | Reloadable film canister system |
| US5931400A (en) * | 1996-03-25 | 1999-08-03 | Klosterboer; Donald H. | Film cartridge and cartridge mounting insert for microfilm machines |
| US6247857B1 (en) * | 1999-08-11 | 2001-06-19 | Eastman Kodak Company | Multistage system for processing photographic film |
| FR2817837B1 (en) * | 2000-12-13 | 2003-08-08 | Neopost Ind | STRIP LABEL DISTRIBUTOR |
| US6963351B2 (en) * | 2001-12-21 | 2005-11-08 | Datacard Corporation | Radio frequency identification tags on consumable items used in printers and related equipment |
| US8295957B2 (en) * | 2007-12-05 | 2012-10-23 | Disney Enterprises, Inc. | Method and system providing a customized audio presentation tailored to a predetermined event sequence |
| US9809416B1 (en) | 2012-12-15 | 2017-11-07 | Southwire Company, Llc | Cable reel length calculator |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3730453A (en) * | 1970-09-21 | 1973-05-01 | Xerox Corp | Early end of tape detection |
| US3734052A (en) * | 1972-05-31 | 1973-05-22 | Mc Graw Edison Co | Cassette with index mechanism for magnetic tape dictating machine |
| DE2441542B2 (en) * | 1974-08-30 | 1977-01-20 | FRAME COUNTING DEVICE IN KINEMATOGRAPHIC CAMERAS | |
| CH612013A5 (en) * | 1976-11-26 | 1979-06-29 | Canon Kk | |
| US4153361A (en) * | 1977-05-04 | 1979-05-08 | Bell & Howell Company | Web cassette with cartridge load |
| JPS56154720A (en) * | 1980-05-02 | 1981-11-30 | Olympus Optical Co Ltd | Film cassette |
| US4443007A (en) * | 1980-09-11 | 1984-04-17 | Pitney Bowes Inc. | Inserter with improved ram mechanism |
| US4418994A (en) * | 1981-10-19 | 1983-12-06 | Panavision, Incorporated | Film magazine for motion picture camera |
| FR2571513B1 (en) * | 1984-10-08 | 1988-03-18 | Aaton Sa | METHOD AND SYSTEM FOR RECORDING, ON THE MARGINAL PART OF A PERFORATED CINEMATOGRAPHIC FILM, CODED INFORMATION AND READING SUCH INFORMATION |
| US4767079A (en) * | 1985-04-05 | 1988-08-30 | Minolta Camera Kabushiki Kaisha | Roll film carrier for reader or reader printer |
| DD245046B5 (en) * | 1985-12-23 | 1996-09-05 | Zeiss Carl Jena Gmbh | Method for detecting and displaying film in aerial photography apparatus |
| JP2801000B2 (en) * | 1986-07-02 | 1998-09-21 | 三菱電機株式会社 | Recording / playback device |
| DE3715179A1 (en) * | 1987-05-07 | 1988-11-17 | Intercolor Gewalt Roehrl Schla | Light-proof supply device having a cutting edge for photographic paper or the like wound on rollers |
| US5153625A (en) * | 1990-03-29 | 1992-10-06 | Anacomp Inc. | Film canister to facilitate diameter sensing |
| US5003333A (en) * | 1990-04-09 | 1991-03-26 | Eastman Kodak Company | Pulse generating mechanism for a web-roll |
-
1990
- 1990-09-27 US US07/590,470 patent/US5247323A/en not_active Expired - Lifetime
-
1991
- 1991-09-24 CA CA002052171A patent/CA2052171A1/en not_active Abandoned
- 1991-09-26 AT AT91918232T patent/ATE143737T1/en not_active IP Right Cessation
- 1991-09-26 EP EP91918232A patent/EP0504369B1/en not_active Expired - Lifetime
- 1991-09-26 DE DE69122492T patent/DE69122492T2/en not_active Expired - Fee Related
- 1991-09-26 JP JP3517011A patent/JP2744845B2/en not_active Expired - Fee Related
- 1991-09-26 WO PCT/US1991/007039 patent/WO1992006404A1/en active IP Right Grant
-
1993
- 1993-06-03 US US08/071,529 patent/US5389992A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE69122492T2 (en) | 1997-02-20 |
| WO1992006404A1 (en) | 1992-04-16 |
| DE69122492D1 (en) | 1996-11-07 |
| JP2744845B2 (en) | 1998-04-28 |
| EP0504369A1 (en) | 1992-09-23 |
| ATE143737T1 (en) | 1996-10-15 |
| US5247323A (en) | 1993-09-21 |
| US5389992A (en) | 1995-02-14 |
| EP0504369A4 (en) | 1993-02-24 |
| EP0504369B1 (en) | 1996-10-02 |
| JPH05503174A (en) | 1993-05-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |