US3688672A

US3688672A - Keyboard operated phototypesetting display machine

Info

Publication number: US3688672A
Application number: US22649A
Authority: US
Inventors: Ellis P Hanson; George J H Sausele
Original assignee: Compugraphic Corp
Current assignee: Compugraphic Corp
Priority date: 1970-03-25
Filing date: 1970-03-25
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: GB1353691A; DE2114547A1; GB1353692A

Abstract

The keyboard operated phototypesetting display machine produces continuous photographic paper output copy in 15 to 72 point range sizes which is top-aligned for all point sizes. A continuous rotating drum supports a font strip containing two rows of characters, timing slits, and coded data indicating the width of each of the characters. The selected characters are strobed to a magnifying lens and projected onto an image plane containing the photographic paper. The desired point sizes are obtained from individual lenses which are mounted on a rotatable lens turret which is located and locked to position a lens at a lens station by a point size selector knob. The spacing of the projected images of the characters is determined by a photoconductive pick-up which senses the character width information on the font strip and also by coded signals from the keyboard. Computer and control circuitry automatically determines the correct spacing to energize a stepping motor to escape the photographic paper. Means are provided whereby the letterspace escapement may be automatically decreased in selectable increments for all point sizes. The photographic paper is loaded at the image plane from a cassette and the output copy is received, in turn, into another cassette for easy removal from the machine. A

Description

United States Patent Hanson et al.

[ Sept. 5, 1972 [54] KEYBOARD OPERATED PHOTOTYPESETTING DISPLAY MACHINE [72] Inventors: Ellis P. Hanson, Rockport; George J. H. Sausele, Lynnfield, both of Mass. 9

[73] Assignee: Compugraphic Corporation,

Wilmington, Mass.

[22] Filed: March 25, 1970 [21] Appl.No.: 22,649

[52] US. Cl ..95/4.5, 355/55 [51] Int. Cl ..B41b 15/08, B41b 17/00 [58] Field of Search ..95/4.5 R; 355/55 [56] References Cited UNITED STATES PATENTS 2,999,434 9/1961 Higorinet et a1. ..95/4.5

2,790,362 4/1957 Higonnet et a1. ..95/4.5

2,652,755 9/1953 Higonnet et a]. ..95/4.5

2,475,497 7/1949 Harrold et al. ..95/4.5

3,191,510 6/1965 Carmack et al. ..95/4.5

3,064,545 11/1962 Scantlin ..95/4.5

3,000,279 9/1961 OBrien, ...95/4.5

3,183,806 5/1965 O'Brien et-al. ..95/4.5

Primary Examiner-Samuel S. Matthews Assistant Examiner-Robert P. Greiner Attomey Watson, Cole, Grindle & Watson [57] ABSTRACT The keyboard operated phototypesetting display machine produces continuous photographic paper output copy in 15 to 72 point range sizes which is topaligned for all point sizes. A continuous rotating drum supports a font strip containing two rows of characters, timing slits, and coded data indicating the width of each of the characters. The selected characters are strobed to a magnifying lens and projected onto an image plane containing the photographic paper. The desired point sizes are obtained from individual lenses which are mounted on a rotatable lens turret which is located and locked to position a lens at a lens station by a point size selector knob.

The spacing of the projected images of the characters is determined by a photoconductive pick-up which senses the character width information on the font strip and'also by coded signals from the keyboard. Computer and control circuitry automatically determines the correct spacing to'energize a stepping motor to escape the photographic paper. Means are provided whereby the letterspace escapement may be automatically decreased in selectable increments for all point sizes.

The photographic paper is loaded at the image plane from a cassette and the output copy is received, in turn, into another cassette for easy removal from the machine. A cutter mechanism is provided to sever the paper after a take.

5 Claims, 16 Drawing Figures PATENTEB 5W 3.688.672

' sumunrs KEYBOARD OPERATED PHOTOTYPESETTING DISPLAY MACHINE This invention relates to keyboard operated phototypesetting display machines and, in particular, to such machines which produce continuous photographic paper output copy with a variable point size range wherein topof-body alignment is provided for all point sizes.

An advantageous feature of the phototypesetting machine of this invention is that it is the first machine of its type which enables a headline strip output to be obtained from a keyboard input. Prior art headline strip machines require manual manipulation of a character storage means in order to select characters for a desired output. These manual prior art machines are known as photolettering machines such as, for example, the AM Headliner, Typro (a registered trademark), the Friden .Typro, etc. The keyboard operated phototypesetting display machine disclosed herein represents a vastly superior product over the prior art photolettering machines as will be evident to those skilled in the art from the following description.

A direct input keyboard is an integral part of the photo unit and provides a production capability heretofore unattainable in the larger point sizes. Keyboard input speed ranges from 3 characters per second in 72 point to 14 characters per second in 15 point. An eightlens turret provides instant access to l5, I8, 24, 30, 36, 48,60 and 72 point sizes. Intercharacter spacing for each pointsize is determined automatically by the control circuitry of the unit. No calculations by the operator are necessary. 7

The characters appear on font strips, there being two font strips mounted on a rotating font drum, and which are easily installed and removed so as to provide a position. Each font strip contains two parallelly spaced rails and a given rail is selected by operating an appropriate lever mechanism on the control panel.

A nominal character width and timing mark is associated with each character on the font strips. Photoconductive sensors detect the timing mark and width data which are processed by the computer to determine the strobing of the characters and escapement signals for advancing the paper strip to provide intercharacter spacing. A three-position switch on the control panel enables the operator to select an automatic mode wherein character space compensation, in accordance with the various output point sizes, is determined from a table stored in the machines; or a mode which enables the operator to switch in a desired range of character space compensation values regardless of the point size output; or a mode in which letterspace compensation is not provided. The aforementioned modes of operation thereby enable the operator to vary the intercharacter spacing over a widely variable range.

The paper or film upon which the output is produced is packaged in a special light-tight throwaway plastic magazine which provides a 400 foot strip and which is installed at a specially designed cassette receiving station. The output strip is automatically fed to a cassette receptacle at the front of the machine. Operation of a paper cutter lever cuts the paper at the end of a take thereby enabling the cassette receptacle to be removed so that the paper or film may be-exposed. The paper is advanced in accordance with the escapement signals generated by computer circuitry in accordance with the aforementioned character space calculations by a stepping motor. 7

It is a primary object of this invention to provide an automatic keyboard operated phototypesetting display machine which produces continuous photographic paper strip output copy.

It is another object to provide such a machine wherein the output copy is top-of-body aligned. It is yet another object to provide such'a machine having a variable selectable point size output range. It is yet another object to provide such a machine having automatic letterspace compensation. A still further object is to provide such a machine which affords a large number of characters and a wide-variety of character types. It is still yet a further object to provide .such a machine whichis considerably faster than the former manual prior art machines and yet which is inexpensive to manufacture and maintain.

These and other objects and features of the invention will become apparent from the following specification and the drawings which disclose an exemplary embodiment of the invention wherein: a

FIG. 1 is a perspective view to illustrate the various component assemblies of the photocomposing machine;

FIG. 2 is a plan view of the machine illustrated in FIG. 1 showing the character presentation assembly, the projection lens assembly, and the paper advance assembly;

FIG. 3 is a side elevational view of the apparatus shown in FIG. 2;

FIG. 4 is a plan' view of the mechanism;

FIG. 5 is an elevation view of the font drum shift mechanism taken along lines 5-5 of FIG. 2;

FIG. 6a illustrates the relationship of the timing marks, character width information, and negative character images on the font strip; a

FIG. 6b illustrates another embodiment of the font strip;

FIG. 7 is an enlarged plan view showing the relationship of the flash lamp assembly, the photoconductive detectors, the font strip, the aperture mask and screen, and the lens station of the character presentation as sembly shown in FIG. 2; a

FIG. 8 is an elevation view of the mechanism for retaining in a selected position the lens turret of the projection lens assembly shown in FIGS. 2 and 3;

FIG. 9 is a sectional view of the paper feed guide and paper feed mechanisms of the paper advance assembly taken along line 9-9 of FIG. 2;

FIG. 10 is a side elevation view of the cutter blade assembly associated with the paper advance assembly illustrated in FIG. 1;

FIG. 11 illustrates the cutter blade;

FIG. 12a is a representation of the manner in which the photographic output of the display machine is assembled to form a paste-up;

FIG. 12b shows the relationship of the character image at the font strip to its image at the image plane with respect to the optical axis; and

font drum shift GENERAL DESCRIPTION FIG. 1 illustrates the primary components of the phototypesetting display output machine wherein base 20, which includes the necessary power supplies and computer and control circuitry to operate the machine, supports a frame 22 to which is mounted photo-unit assembly 24, keyboard 26, and control panel 28. A cover (not shown) encloses photo-unit assembly 24 to exclude extraneous and unwanted light therefrom.

Photo-unit assembly 24 consists of three subassemblies; character presentation assembly 30, projection lens assembly 32, and paper advance assembly 34. Character presentation assembly 30 includes font drum 40 which continually rotates in a plane normal to the character top line which is established at a fixed image plane within paper advance assembly 34. Font strip 42 is accurately positioned on font drum 40 and contains two rows of characters, the necessary timing slits to provide synchronization signals to the computer and control circuitry for strobing the selected characters, as well as the character width information for appropriately escaping the photographic paper. A mechanism is provided which enables font drum 40 to be laterally shifted to one of two positions whereby a desired one of the two rows of characters is positioned to be presented to projection lens assembly 32 so that a selected character may be strobed and projected to the image plane within paper advance assembly 34. Font drum 40 is manually rotatable by knob 43 for the purpose of initially aligning the machine for test purposes.

Projection lens assembly 32 includes a rotating turret assembly 50 on which are mounted a plurality of lenses each having a different power of magnification. Turret assembly 50 is rotated to a desired position by manual operation of turret knob 52, thereby enabling a desired character size, variable from to 72 point, to be projected onto the image plane within paper advance assembly 34. Four lower magnification lenses are mounted on one side of turret assembly 50 and the four remaining higher magnification lenses are mounted on the opposite side of the turret assembly as will be more fully described hereinafter.

Cartridge holder 58 receives and retains a 400 foot reel of 35 mm type S paper which is threaded into paper advance assembly 34 and into a paper advance mechanism therein. The photosensitive paper or film is then automatically escaped in accordance with the character width information on font strip 42 and coded interword spacing information from the keyboard. Lever 62 operates cutter mechanism 64 to cut the paper at the end of a take." The photographed paper is received in a cassette at receiving station 60 for easy removal from the machine.

The characters to be photographed are selected by depression of the keys on keyboard 26 which has a standard keyboard layout known to those skilled in the printing art. The keyboard has 49 printing keys including end mark and start mark, as well as an end take key to feed an end of take" signal into the paper receiver within paper advance mechanism 34. The various control features of the keyboard will be described more fully hereinafter with reference to the computer and control circuitry. A 'ITS code is generated in response to the depression of the keys on the keyboard and decoded by decoder circuitry within the computer.

Control panel 28 contains additional control switches, buttons and indicators to initialize the computer and indicate to the operator certain operating conditions of the phototypesetting machine to be more fully described hereinafter.

DETAILED DESCRIPTION OF CHARACTER PRESENTATION ASSEMBLY With reference to FIGS. 2 and 3, character presentation assembly 30 further includes shaft 80, rotatably mounted within drum carriage 82, to which is fixed font drum 42. Shaft is rotated continuously in a direction indicated by the arrow via timing pulleys 84, 85, timing belt 86, and motor 88 at a speed of approximately 810 r.p.m. Drum carriage 82 is slidably secured to guide

rods

90, 92 by means of bearings (not shown) to afford lateral movement of font drum 40. Timing belt 86 is narrower than the grooves in pulleys 84, to enable the belt to move within the grooves as drum carriage 82 is moved laterally to either one of two positions.

Guide rods

90, 92 are secured in mounting bracket 94 which is in turn fixed to the machine frame. Knob 43 enables the operator to manually rotate shaft 80 and font drum 40 to place the font drum in a convenient position to replace a font strip.

With continuing reference to FIG. 2, and additional reference to FIGS. 1, 4 and 5, the mechanism for actuating drum carriage 82 to afford the aforementioned lateral movement of font drum 40 consists of lever 1 10 which is pivotally mounted to the machine frame at pivot l 12. Rod 114 is secured at one end 116 thereof to lever the other end of rod 114 is attached to link 1 18 which is pivotally mounted to the machine frame at pivot 120. Line 122 is pivotally mounted to the machine frame at pivot 124 and to link 118 by pin 126. Leg member 128 connects links 118, 112 to drum carriage 82 by means of pin 126. Spring 130 is fastened to the outer ends of links 118, 112 by

pins

132, 134. The aforedescribed apparatus forms an over-center mechanism for shifting and locking drum carriage 82 at opposite ends of its lateral traverse in the following manner. Lever 110 is pivoted about pivot 112 by manual movement afforded by handle 136. It is apparent that clockwise rotation of lever 110 causes link 118 to rotate clockwise about pivot 120, thereby moving

links

118, 122 into the position shown in full outline in FIG. 4 and moving drum carriage 82 and font drum 40 upward with reference to FIG. 2. Spring 130 locks links 1.18, 122 in their over-center position. Counterclockwise movement of handle 136

moves links

118, 120 into the position illustrated in phantom in FIG. 4 and produces an opposite lateral movement of font drum 40. The lateral movement of font drum 40 is limited in each direction by

stops

138, 140 which are respectively driven into abutting relationship with opposite surfaces of bracket arm 142. The stops ensure that font drum 40 is accurately located so that each row of characters on font strip 42 is precisely positioned to present a selected character to lens projection assembly 32, as will be more fully described below.

. FONT STRIP Font strip 42 is preferably two strips of dimensionally stable photographic film on which have been developed negative timing marks 150 and negative type characters 152 which are provided in two

rails

154, 156 which extend in parallel spaced rows as indicated in FIG. 6a. Font drum 40 is divided into an upper magazine 158 and a lower magazine 160 (as illustrated in FIG. 3), and one font strip is mounted to font drum 40 at each magazine. Each font strip 42 has 56 characters; therefore, there are 112 characters in each

rail

154, 156. The manner by which the font strips are mounted to font drum 40 is described in copending U. S. application Ser. No. 804,466, which is assigned to the same assignee as the present application. Character width information is afforded in binary coded format by slits 162 which provide six bits of data, thereby enabling a width count of 64, to be indicated.

Timing marks 150, type characters 152, and width information 162 aretransparent, thereby enabling light ,to be projected through them. Timing marks 150 are positioned with respect to type characters 152 so as to provide the necessary timing signals to the computer to enable a selected type character to be strobed at the proper time and projected in the proper position on the line being set on the photographic paper at the image plane as font drum 40 rotates continuously. As illustrated in FIG. 6a, the adjacent characters in

rails

154, 156 have the same character width. Therefore, one set of corresponding bit data is sufficient for the width information for both of the rails. The two extra timing slits 163, 164 are necessary to set or condition circuitry within the computer to generate the character strobe signal as will be described below. The font strip illustrated in FIG. 6a is called a duplexed strip. since the same character width information pertains to the characters in each of the

rails

154, 156.

FIG. 6b illustrates a modification of the font strip 42, wherein-the adjacent characters in

rails

166, 168 have different character widths, thereby necessitating two sets of character width information. The character width information is afforded by providing one set of character width data for each

rail

166, 168. This is illustrated in FIG. 6b by binary data 169, 170, which, respectively, contains the width information for the character t in

rails

166, 168. Two sets of binary coded data are similarly provided for the remaining characters in

rails

166, 168. The manner in which the width information for each railis detected and made known to the computer is described below.

The characters 152 on the font strip are inverted as they appear to lens station 178 (FIG. 7) so that their inverted image is right-side up at the image plane in advance assembly 34.

FIG. 7 illustrates the flash lamp assembly for strobing a selected character to that lens which has been selected to project the character onto the image plane; as well as the mechanism whereby the character width and the timing information on font strip 42 are sensed to provide the computer and control circuitry with the necessary signals to strobe the selected character at the precise instant at which it is positioned for projection; and to generate the necessary escapement of paper drive mechanism 34 in accordance with the particular character and point size selected.

Flash lamp 172 is mounted by bracket 174 to the machine frame behind the two rails of characterson font strip 42 aligned with aperture 176 so that excitation of the flash lamp'projects an image of the selected character through the aperture to a lens station 178 which is positioned as more fully described below. Aperture mask 180 is mounted over aperture 176 to provide a clear definition of the strobed character image to the lens station through aperture 182 in light shield 184. Photoconductive member 186 is mounted so that the individual photoconductive elements 186a-g thereof are in alignment with the character width information and timing slits on font strip 42. Photoconductive element 186a detects timing slits and photoconductive elements 186b-g select the six bit width data 162. Light source 188 is mounted behind font strip 42 to provide illumination of the'character width and timing information to project this data to the photoconductive elements 186a-g through cylindrical lens 190. The photoconductive elements 186a-g, light source 188 and cylindrical lens 190 are mounted by bracket 192 to arm 194 of. drum carriage 182 to be movable with it, thereby maintaining the width and timing information in positionto be sensed as font strip 42 is laterally moved to either of its two positions. Conversely, the mounting of flash lamp 172, aperture plate 177 and mask to the machine frame positions a desired rail of characters to be detected as font strip 42 is laterally moved. The sensed information is provided to the computer control circuitry for character width control to be more fully described below. Light shield 184 prevents stray light from reaching the photosensitive film or paper in advance assembly 34.

PROJECTION LENS ASSEMBLY Continuing with reference to FIGS. 2 and 3, projection lens assembly 32 includes turret lens assembly 50 mounted to turret index shaft which is rotatable within bearing 192. Indexing shaft 194 has mounted thereon turret indexing gear 196, which engages idler gear 198, which in turn is engageable with turret drive gear 200 on shaft 190. Idler gear 198 is rotatably mounted within arm 202 extending from bearing 192. Thus, a clockwise or counterclockwise movement of turret knob 52 generates a corresponding clockwise or counterclockwise rotation of turret index shaft 190 and turret lens assembly 50.

Turret lens assembly 50 includes eight-high-quality lenses 212-219, which are radially mounted, and spaced equidistantly, on turret 210. In the preferred embodiment of this inventiomthe high-quality lenses and their respective focal lengths are selected to provide a magnification of 10. Thus, to provide a variable increment in the point size of the paper output copy from 15 to 72, the lenses respectively, have magnifying powers of 1.5, 1.8, 2.4, 3.0, 3.6, 4.8, 6.0 and 7.2. The lower power lenses, that is, lenses 212-215, are mountedto that side of turret 210 which faces away from character presentation assembly 30; and the high power lenses, i.e., lenses 216-219, are mounted to the opposite side of turret 210 so that these lenses are closer to character presentation assembly 30. The mounting of the lenses to the respective sides of turret 210 is necessary to afiord the proper focal length for the individual lenses to ensure that the proper magnification is obtained at the image plane within paper advance assembly 34. v

includes roller 234 rotatably mounted at the other end thereof to be in engagement with the periphery of turret 210. The positive engagement of roller 234' with the peripheral surface of turret 210 isensured by spring 236. Thus, as turret 210 is rotated by turret knob 52, I

roller 234 will engage a respective detent 220-227 to retain a selected lens at lens station 178 (FIG. 7).

For reasons which will become more fully apparent hereinafter, it is necessary to provide information to the computer which indicates that particular point size which has been selected by turret knob 52. This information is generated by eight-position switch 240 (FIGS. 2 and 3, the shaft of which is fixed to rotate with indexing shaft 194, thereby generating electrical signal inputs to the computer and control circuitry which indicate that particular lens magnification that has been selected by turret knob 52.

PAPER ADVANCE ASSEMBLY Paper advance assembly 34 will be described with reference to FIGS. 2 and 9. Cartridge holder 58 is mounted to the side of paper advance assembly 34 and receives a cassette containing a supply of 35 mm film, the leading edge of which is received in channel 260, partially formed by paper guide plate 262 and paper backing plate 264. The location of channel 260 is at the image plane 261. With specific reference to FIG. 9, backing plate shims 266, 268 are provided to adjust the width of aperture 260.

Paper feed keys

270, 272 receive the opposite edges of the paper film to vertically guide it along channel 260. The paper. film in channel 260 is fed into, and advanced by, paper feed wheel 272 and pressure roller 274. Paper feed wheel 272 is fixed to paper feed shaft 276, mounted by bracket and bearing assembly 278 to the machine frame, and driven through gear 280, fixed to the other end of paper feed shaft 276. Gear 280 meshes with, and is driven by, spur gear 282, mounted to shaft 284, which is stepped by stepping'motor 286 in accordance with control pulses generated by the computer and control circuitry in a manner to be more fully described below. The paper passes through transverse cutter slot 290, which is formed by mounting aperture plate 292 and paper backing plate 294 in spaced relationship to backing plate 264 and paper guide plate 262, respectively, so that the channel 260 continues in a straight line along the aforementioned image plane within paper advance assembly 34.

With particular reference to FIG. 2, pressure roller 274 is fixed to shaft 296, mounted in roller frame 298, and this frame is pivotally mounted about roller frame shaft 300 in pressure roller bracket 302. Pressure roller 302 is fixed to the side of paper advance assembly 34 as illustrated. Pressure roller stud 304 passes through roller frame 298 and threadably engages paper guide plate 262 to maintain pressure roller 274 in positive and firm contact with the film threaded between the pressure roller and paper feed wheel 272'. The unthreading of pressure roller stud 304 enables roller frame 298-to be rotated away from paperguide plate 262 so that access is provided to channel 260 and paper feed wheel 272.

The threading of the film in channel 260 through paper feed wheel 272 and pressure roller 274, engages arm 306 of two-position switch 308 to inactivate the switch, thereby affording an indication that film is loaded and ready for a take." With no film present in channel 260, arm 306 is allowed to rotate so as to activate switch 308 thereby providing a no film" signal which lights an appropriate indicator on control panel 28 (FIG. 1).

The output display machine includes a paper cutter mechanism for cutting the paper film after a take as isillustrated in FIGS. 2, 10 and 11. The film is severed by blade 310 fixed to cutter shaft 312 within transverse cutter slot 290. Cutter shaft 312- is slidably mounted within cutter bracket assembly 314 and biased in a downward position below the paper by spring 316 which has one end abutting against upper plate 318 of cutter bracket assembly 314, and the other end fixed to cutter shaft 312 by clamp 320. Blade 310 severs the paper by a vertical upward movement of cutter shaft 312 as cutter lever 62 (FIG. 1) is depressed by the operator, thereby rotating cutter link arm 324 about a pivot (not shown) and elevating cutter shaft 312 and blade 310.

DISPLAY OUTPUT The paste-up also illustrates the versatility of the phototypesetting display machine in that'a great number of character types are selectable in a point size range extending from 15 to 72 points.

Strips

350, 352, 354 are obtainable from a phototypesetting machine as described herein without the necessity of changing the font strips on the font drum 40, although it is apparent that a greater number of character type may be afforded merely by changing the font strips on the font drum.

The optical system may be aligned in various ways to suit the particular work to be accomplished. Thisis readily afforded by adjusting the lenses 212-219 relative to the member 210. A preferred andnovel alignment is accomplished by aligning the upper left-hand corner of the type body on a common reference point 362 (FIG. 12a) at or near the top edge of the photosensitive strip 358. This preferred alignment may be accomplished by placing both point 362 and the corresponding point on the font strip on the optical axis 360 of the machine. Such an alignment enables setting all sizes of type close to the edge of the photosensitive strip and for proper set wise fitting when sizes are changed within a line of type.

The precision with which optical axis 366 intersects the image plane is determined primarily by the positioning of a selected lens at lens station" 178 and the accuracy with which the film in channel 260 is maintained in vertical alignment. The necessary accurate positioning of a lens at lens station 178 (FIG. 3) is provided by the aforedescribed locking mechanism illustrated in FIG. 8. The vertical alignment of channel 260 is obtained because the edges of the film in channel 260 are guided by paper feed keys 270, 272 (FIG. 9).

It is apparent that'the film in channel 260 may be escaped to any position to the right of a former position so that any desired interword and/or interletter spacing may be obtained by the appropriate pulsing of stepping motor 286, For example, with reference to FIG. 12a after the T hasbeen strobed, the film may be advanced so that the optical axis intersects the film at point 368 to enable the next letter, o," to be strobed onto the film. The derivation of the escapement pulses in accordance with the character widths and the automatic letter space compensation value, which is determined in accordance with the point size and desired letter spacing, is described below with reference to the description of the computer and control circuitry.

The relationship of the negative character at the position where it is strobed at font strip 42 to the projected image at image plane 261 is illustrated in FIG. 12b. It is apparent from the fundamentals of optics that if the character is strobed at a position corresponding to that indicated by 370, its inverted image will appear at position 372 on image plane 261. Therefore, optical axis 360 may intersect the imageplane just below aperture 374 at paper advance assembly 34. The manner in which the characters are strobed at the proper instants so that they are projected to the image'plane to be in top-of-body alignment is described below with reference to the computer and control circuitry- COMPUTER AND CONTROL CIRCUITRY Character Strobing The apparatus for determining the proper instant to strobe a selected character to project it from the font strip to the image plane, and for computing and controlling the necessary stepping of the stepper motor to escape the film in accordance with the character widths and automatic letter space compensation is illustrated in block and schematic format in FIGS. 13 and 14.

The depression of a key on a keyboard 26 generates a strobe signal on line 400 which sets LKOUT flip-flop 402 to generate a lockout pulse (LKP). Simultaneously therewith, the code generated by the depressed key is fed to keyboard decoder 404 which decodes all the character codes, space codes, and control functions used to operate the phototypesetter. For all codes except a space code or a control function code, the LKP pulse sets FLASH flip-flop 406. FLASH flip-flop 406 is only set if there is a key depressed which requires an image on the output film and this condition is established by the negative SC/CF (Space code/Com trol function) signal from decoder 404.

The timing marks on the font strip are detected by the photoconductive elements of photoconductor 186 (FIG. 7) and amplified by amplifier and delay circuit 408 to produce negative clock signals (CLK) and negative delay signals (delay). A synchronizingpulse is obtained each revolution of the font drum from an opening between two adjacent ends of the font strips on font drum 40 to synchronize the computer circuitswith the drum rotation and this pulse sets SYNK flip-flop 412 which produces, in turn, a flash clear pulse (F C?) and a flash load pulse (FLP) from delay circuits 414, 415, respectively. FCP resets counter stages 418, 420, 422 of counter 416 through

drivers

424, 426, 428. FLP stores the complement of the keyboard code value, ob-

tained from inverters 430,- into counter stages 418, 420,

422 through

drivers

432, 434, 436 and emitter-gated preset drivers 438, 440. This code represents, by binary designation, each successive character position for the characters on the font strip, regardless of the rail in which the character lies. For this purpose, the TTS codes from the keyboard are assigned numerical values for the font strip count in accordance with the following tables: 4

TABLE r Each rail of characters on each of the font strips is divided into two groups, upper case and lower case. The particular group in which a selected character resides is determined by keyboard decoder 404 to set upper case flip-flop so that a 32 value is preset into counter 416 if the selector character is in the'upper case group. For a lower case character no additionalgunt is set into counter 412. The upper case signal, UC, sets stage 6 of counter stage 420 through the indicated driver in preset drivers 440 to provide the aforementioned 32 count. Keyboard decoder 404 also sets upper magazine flip-flop 444 to reset a 128 count value into counter 416 if the selectedcharacter lies in the upper magazine (UM-FIG. 3). This count is set into counter 416 by resetting stage 7 of counter stage 420 via the indicated driver in preset drivers 440. In this manner each character in the lower and upper magazines is designated by a different complement value set into counter 416, thereby enabling each character on the font strip to be identified by a corresponding binary designation.

With the aforementioned character position information loaded into counter4l6, clock pulses from clock amplifier 408 are. entered into the first stage (0 of counter stage 418 via OR

gates

507, 508, until the counter stages 418, 429, 422 are filled up, whereupon the last stage OFl of counter stage 422 is set. The next subsequent clock pulse resets SYNK flip-flop 410 to fire flash tube 172 through driver 446. The character selected from the keyboard is properly aligned as a result of the counting of the clock pulses from the beginning of the font strip to the selected character,

AUTOMATIC LETTER SPACE COMPENSATION AND CHARACTER ESCAPEMENT Now that the selected character has been strobed and projected onto the film into an aligned position, the film must be escaped to provide the proper positioning for the next selected character. Before continuing with the description it is advantageous to provide an explanation of the relationship between the character widths designated on the font strip, the arithmetic values used by the computer in deriving'the escapement pulses,'and the unit values chosen for the actual escapement itself.

The setwise width is defined in'terms of 'sets and .a set is, in turn, defined in terms of a point. For example, one-set is equivalent to one-eighteenth of a point; three-set'is equivalent to one-fifty-fourth of a point. The term EM is defined as a distance in points which is equal to the body or height of the type measured in the setwise direction. A point is defined as one seventysecond of an inch. The above terminology is that which is used in the typesetting art; however, the defined units of the set are in accordance with the units used with the machine disclosed herein. g

In this invention, the character widths indicated on the font strip are in three-set and the arithmetic in the computer is carried out on a three-set basis, primarily to obtain better resolution for defining the escapement pulses. After the computer has performed the escapement computations, the actual escapement pulses are determined by a divide-by-three circuit to bring the actual escapement back to one-set. Each step of the film escapement is equal to one-sixth of a point. This width is, of course, determined by the characteristics of the stepping motor, the pulses applied thereto, and the gearing between the motor and the paper advance mechanism.

'LE'ITERSPACE COMPENSATION Because the width information designated on the font strip is a constant or relative value for each respective character, it must be scaled in accordance with the point size output selected or, in other words, in accordance with the lens size selected. Such scaling gives a proportional enlargement or reduction of paper feed in accordance with the lens size selected. However, such sealing does not always produce the optimum or desired graphic appearance for a particular size or style of type. It is desirable to modify or compensate for the scaled interletter spacing, and even enable the letter spacing to be varied over a range of increments regardless of the point size output selected. The phototypesetting machine described herein provides: (1) a fixed compensation dependent on the point size output selected, (2) a variable compensation which is independent of the point size output and is inserted by manual switches on control panel 28, or (3) no letterspace compensation.

, 12 COMPUTER ESCAPEMENT COMPENSATION The aforementioned escapement computations are performed in the following manner. The previously described resetting of FLASH flip-flop 406 turns on first escape flip-flop 450 to generate escapement clear pulses (ECP), 'escapeme ithaad ulses (ELP), and their negative counterparts (ECP, E from

delay circuits

452, 454, respectively. ECP clears counter 416 by means of OR ate 456, driver 458, and

drivers

424, 426 and 428. EC clears counter 460 and, more particularly, counter stages 462 and 464thereof through inverter 466 and

drivers

468, 470, and 472. The width codes (FIG. 6a) overlap the timing marks and the aforedescribed pulse ECP gates the appropriate width code'into width register 476.

The character width data sensed by the aforedescribed photo-sensitive elements 186b-g, is a'mpulse is applied to inverter 484 and, by means of driver 9 486, activates drivers 488 to transfer a lens size subtraction or a selected value complement into counter stage 462 and the first two stages of counter'stage 464 of counter 460 from lens size subtraction matrix 490. The negativeescapement load pulse also is applied to inverter 492 and driver 494 to activate drivers 496, thereby loading a lens size scaling factor complement into the last stage of counter stage 420 and the stages of counter stage 422. The lens size scaling factor complement is obtained from lens multiplier matrix 498. The lens size is provided to lens multiplier matrix 498 by means of the aforementioned eight-position switch 240 which is driven by the turret knob indexing shaft 194 (FIG. 2).

The activation of first escapement flip-flop 450 and ECP and ELP also activate speed-up oscillator 500 by means of AND gate 502 as indicated in FIG. 14. Speed up oscillator 500 then generates 3,000 I-Iz pulses which are counted in counter stage 462 of counter 460 after being delayed in delay' circuit 504, and counter 416 counts the inverted oscillator pulses from inverter 506 by means of OR gate 508. The counter stages 418, 420, of counter 416 count the oscillator 500 pulses until the subtraction value is counted in, since the complement of the width value was originally transferred from width register 476; if the third counting stage of counter 420 sets, count escapement operating pulse (CEOP) reloads the value from width register 476 into the first stages 418 and the first two stages of counter stage 420 of counter 416 and resets the third stage of counter stage 420 to add one count to the higher multiplying factor stage 422. A pulse, count escapement operating pulse plus two (CEOPl-Z), is provided by delay through circuits 522, 524 to add one. count to counter 416 by means of OR gate 508. The value in counter 416 is therefore the width complement value plus one and the aforementioned oscillator pulses from speed-up oscillator 500 again begin to cycle counter 416 and counter 460. During this count cycling, counter 460 will eventually overflow, thereby setting the third stage of counter stage 464 to produce a signal PNY 64 which resetsfirst escapement flip-flop 450 to thereby set secondescapement flip-flop 530 to activate a second speed-up oscillator 532. Signal PNY 64 determines the end of theabove-described subtraction process.

Counter 416 continues to cycle; however, oscillator pulses from the second speed-up oscillator 532 step motor driver flip-

flops

534, 536. Motor driver flip-

flops

534, 536 divide the second oscillator pulses by a factor of three for operation of the stepping motor control flip-

flops

538, 540 as well as the motor supply switch 542. Motor supply switch 542 applies a negative 40- volt output to the coils of stepping motor 550 during the first 500 microseconds of a step pulse, and then maintains a holding voltage of minus 12 volts on the coils, thereby ensuring positive stepping action with a low holding current.

The compensated escapement value remaining in counter stage 422 after the above-described counting operations, is incremented by pulses from the second speed-up oscillator 532 via OR gate 508 through

stages

418 and 420. Eventually, the last stage of counter stage 422 will be set, thereby setting flip-flop 560. The output from flip-flop 560, plus the trailing edge of the counter escapement operating pulse, resets second escapement flip-flop 530, thereby terminating; the escapement operation as speed-up oscillator 532 is turned off. The resetting of the second escapement flipflop 530 also resets LKOUT flip-flop 402 and energizes a key release solenoid until the aforementioned strobe signal on line 400 disappears. The phototypesetting machine is now ready for another keyboard entry whereupon the above-described operations are repeated.

Y The following examples of actual escapement calculations demonstrate the above-described arithmetic letter space compensation in detail for an additional understanding of that portion of the computer circuitry. In the first example, the lens size subtraction value is greater than the nominal character width value;

' and in the second example, the lens size subtraction value is less than the nominal character width value.

' EXAMPLE NO. 1

In this exam'ple, the nominal character width is arbitrarily selected as 54, which is the three-set value of an EM. The lens size subtraction value is arbitrarily chosen to be 60. The character width value 54 is stored in counter stages 418 and 420 as a complement .value by setting stages and 3. This is accomplished by ELP activating the appropriate driver stages associated with each of the afo ementioned counter stages as indicated in FIG. 14. ELP stores the lens size subtracting value 60 in counter stages 4," 8," l6 and 32, respectively, of counter stages 462 and .464. Pulses from oscillator 500 are simultaneously counted into both

counters

460 and 416. Also, m stores a multiplication value from lens multiplier matrix 498 in 422; the value depending on what point size has been selected and in accordance with Table III below.

Because the lens size subtraction value is greater than the character width value, counter stages 418 and 420 cycle first. Thus, on the 55th oscillator pulse, counter stage CNT6 sets, thereby triggering counter escapement pulse generator 510, by removing CNT6, and generating a delayed CEOP pulse and an additionally delayed pulse CEOP+2. CEOP re-stores the nominal character width value into the aforementioned stages of counter stages 418 and 420; immediately thereafter, CEOP+2, via OR gate 508, increments counter stage 418 by a count of one. The aforementioned setting of stage CNT6 generated an overflow from counter stage 420 which was carried into the first stage of counter stage 422. At the setting of CNT6 there remained a deficit count of six in counter stages 462 and 464. The aforementioned CEOP and CEOP+2 pulses are interposed between successive oscillator pulses from oscillator 532. Therefore, the oscillator pulse, immediately following the oscillator pulse which set stage CNT 6, and the subsequent oscillator pulses are simultaneously counted again into

counters

460 and 416. However, on the fifth oscillator pulse counter 460 escapement pulse oscillator 532.

There is remaining a deficit value of 47- in counter stages 418 and 420 of counter 416.The oscillator pulses from oscillator 532 /are now applied to these counter stages via OR gate 508. After the 48th pulse, the CNT6 stage will set causing CEOP, CEOP+2 to be generated which re-strobes width data back into counter 416 if there is still-a deficit value in counter stage 422. This cycle continues until the multiplication factor is complete. Eventually, the last stage of counter stage 422 is set, thereby setting escapement terminating flip-flop 560. The setting of flip-flop 560 resets second escapement flip-flop 530 thereby deactivating escapement oscillator 532 to terminate the stepping of the stepping motor of the escapement of the escapement film.

EXAMPLE NO. 2

In this example, the nominal character width remains at 54; however, the lens size subtraction value is arbitrarily selected as 30. The character width value, the lens size subtraction value, and the multiplication value, are inserted into their respective counters as described above with reference to Example I, the only difference being that the different subtraction value resets stages 2," 4," 8 and l 6. The simultaneous counting of oscillator pulses from oscillator 500 into

counters

460 and 416 will result in a setting of counter stage 64 on the 3 lst pulse. The resulting PNY64 signal resets first escapement flip-flop 450, thereby terminating the generation of oscillator pulses from oscillator 500. The deficit value in counter stages 418 and 420 has been reduced by 3 1, thereby leaving a remaining deficit value of 23. Counter escapement operating pulse generator'510 was never triggered because stage CNT6 of counter stage 420 was not set. The resetting of first escapement flipflop 450 by PNY64 sets second escapement flip-flop 530, thereby activating escapement oscillator 532. The oscillator pulses from oscillator 532 are counted into counter stage 418 via OR gate 508. Eventually, counter stage 422 will overflow, as described above, thereby setting escapement terminating flip-flop 560 and deactivating escapement oscillator 532 to terminate the escapement of the stepping motor.

The phototypesetting machine has the capability of providing the above-described letter space compensa- TABLE II DEFICIT VALUES STORED IN LENS SIZE 10 code. SUBTRACTION MATRIX AU M T ATIC MODE TABLE Iv Deficit Values (Three-Set) Point Size SPACE cons I SC THREE-SET VALUES 12 I 15 15 I8 21 24 EN 27 24 30 EM s4 30 3 THIN 18 39 48 s? 23 2 2 asp a TABLE The depression of a space code key on keyboard 26 Multiplication No. Point Size activates 'LKOUT flip-flop 402, and decoder 404 provides space code signal SC, both of which set first 5 l5 escapement flip-flop 450 to generate ECP and ELP, 3 2 thereby clearing and loading counter 416 with the 10 width information stored in width register 476. First 12 36 escapement flip-flop 450 is reset with the leading edge :8 2g 30 of the first pulse from oscillator 500. Space codes are 24 72 therefore not subjected to the above-described lens size Table III lists the point size outputs and their preferred multiplication values in accordance with the invention. As described above, these multiplication values are stored in lens multiplier matrix 498.

If letter space compensation switch 602 is set into the manual position, the operator may select the lens size subtraction value by means of six switches on control panel 28 (FIG. 1). As indicated in FIG; 14, these switches carry the binary designations l, 2, 4, 8, l6 and 32". Thus, the operator may select any lens size subtraction value from 0" to 63.

If the letter space compensation switch 602 is set into the off position, no letter space compensation is provided and the phototypesetting machine will escape strictly in accordance with the escapement value set into stage 422 from lens multiplier matrix 498.

SPACE CODE AND CONTROL FUNCTION CODE OPERATION Control Function Code The depression of a control function key, such as upper case, lower case, upper magazine, lower magazine, does not require activation of either the flash or escapement circuits. Any of these four codes will produce a negative control function pulse from keyboard decoder 404, which thereby prevents flash flip-flop 406 from turning on and resets LKOUT flipflop 402 at the end of the aforedescribed LKP pulse to end the operation of the computer for such a control function key. The function code signals set appropriate control circuits, for example, such as flip-flops 442 and 444 to indicate upper case and upper magazine functions, respectively.

Space Code The generation of a space code will only provide width escapement and not set FLASH flip-flop 406 because of the negative space code pulse output from keyboard decoder 404. Keyboard decoder 404 generates a width value for width register 476 via sixchannel switch 474 in accordance with the width value of a particular space code. Table IV shows the width value in three-set units for the corresponding space compensation operations. Second escapement flip-flop 530 is set to activate oscillator 532 to escape the oscillator in a manner similar to .that described above with reference to the 05" position of lens compensation switch 602.

MISCELLANEOUS SWITCH FUNCTIONS Film feed end-of-take" switch 600 operates second speed-up oscillator 532 to produce motor driver pulses through

motor drivers

534 and 536 thereby advancing the film in paper advance assembly 34, as long as the switch is depressed.

Prime switch 606 resets all the flip-flops in the computer to enable its proper operation when power is first applied to the phototypesetting machine. Repeat FLASH switch 610, on control panel 28, holds the key release circuit energized and sets LKOUT flip-flop 402 for every delay pulse generated by amplifier and delay circuit 408 in accordance with the sensed timing marks on the drums.

Indicators

612 and 614, respectively, provide a visual display for the information in width register 476 and lens multiply matrix 498.

MODIFICATIONS OF THE PHOTOTYPESETTING MACHINE Increased Keyboard Input The operating speed of the phototypesetting to indicate to the operator that the buffer memory is approaching saturation. In such an instance, the operator, on hearing the alarm, would momentarily pause to avoid saturating the memory, which might result in a failure of the phototypesetting machine to print those characters whose keys had been depressed but whose information was not stored in the buffer memory. Non-Duplex Font Strip Operation The phototypesetting machine may be modified to provide an appropriate indication to the computer circuitry of the position of font drum 40 when the non- 'duplex font strips, illustrated in FIG. 6B, are used. As

described above, the non-duplex font strips have two sets of character width information, each set corresponding, respectively, to adjacent characters in the lower and upper rails. In such an instance, the computer must be informed of which set of character width values to read. Such an indication may be provided by mounting a two-position switch to sense either of the two positions in which font drum-40 is placed. Such a switch is indicated as switch 93 on FIGS. 1 and 2. The

lower rail position of switch 93 would connect the escapement clear pulse to width register 476 to transfer the information therein to the above-described counter stages. The upper rail position of switch 93 would connect the escapement clear pulse through an appropriate delay circuit to width register 476. The delay is necessary since the width information for an upper rail character is reused immediately after the data for a lower rail character (FIG. 6b).

COMPUTER CIRCUIT COMPONENTS A detailed description of the individual components of the computer and control circuitry as disclosed in FIGS. 13 and 14 is not considered necessary since each of those components is known to those skilled in the art to which this invention relates. The necessary components described in these Figures are defined by the aforedescribed functions and operations which they perform.

Briefly, keyboard decoder 404, lens size subtraction matrix 490, and lens multiplier matrix 498 may preferably comprise diode matrices. Timing marking amplifier 408 and photo-unit amplifier 410 are discrete amplifiers. Multiplexer switch 474 must have the capability of multiplexing the width data for non-function codes or the width information from photo-unit amplifier 410 to respective inputs of width register 476. Speed-up

oscillators

500, 532 provide a rectangular wave output at a repetition frequency of 3,000 Hz. Preferably, speed-up oscillator 532 (and, for the sake of reducing the number of different circuit components, speed-up oscillator 500) produces several pulses with intermediate delays therebetween before oscillating at its indicated frequency. This provides for desired initial pulsing of escapement motor 286 to enable it to respond quickly from a given rest position.

Counters

416 and 460 are of a type which store a complement value and are filled-up by successive application of pulses to the initial stage of each counter; the overflow from one stage to a successive stage rippling through each counter stage. Motor driver flip-

flops

534 and 536 are interconnected in a manner to provide a divide-by-three circuit, which construction is well known to those skilled in the art. Motor supply switch known to those skilled in the art and require no addi- I tional structural definition to enable the computer and control circuitry to function as described herein.

CONTROL PANEL SWITCHES AND INDICATOR LIGHTS FIG. 1 discloses the layout of the various switches and indicator lights on control panel 28. Three-position selector switch 602 is manually operated to either one of three positions to provide forno letter space compensation (Ofi position), automatic letterspace compensation wherein values stored in lettersize subtraction matrix 490 are transferred to counter 460, or a manual position in which a value may be inserted into subtraction matrix 490 by means of switches 662. The numeral designations I, 2, 4,.8, l6 and 32,respectively, indicate the binary value inserted in matrix 490 by activation of an associated switch. Prime pushbutton switch 606 is depressed each time the machine is initially activated by on/off switch 658 in order to condition the computer and control circuitry for operation. Power indicator light 656 indicates when the machine is Oh; no film indicator light 600 indicates when no film is present in paper advance assembly 34; shift indicator light 650 is lighted when the shift key on keyboard 26 is depressed; and upper magazine indicator light 652 is lighted when the upper magazine key is depressed on keyboard 26 to indicate to the operator whether he is selecting characters from the upper magazine of font drum 40. When the cover is on the machine upperrail and lower rail" designations' are provided to indicate the position of lever 110 (as best seen in FIGS. 1 and 2).

' on keyboard 26 causes all other keys to be interlocked so that no other key can be depressed until the phototypesetting machine has completed the necessary escapement of the paper or film in paper advance assembly 34 in position to receive a successive character image. Such an interlock may comprise an electromagnet which is positioned so that its flux causes a magnetic primary member to be moved, thereby causing interlock arms connected to the primary member to engage the key link arms to prevent depression of their respective keys. The magnet is deactivated when the phototypesetting machine has completed its operation by removal of strobe signal 400 previously described. However, use of the Increased Keyboard Input described above under Modifications of the Phototypesetting Machine eliminate the need for any keyboard interlock mechanism.

What we claim is:

l. A phototypesetting machine for producing promeans for carrying by strobing said character images with a pulse of light,

means for projecting said selected character images onto said photosensitive strip,

means for advancing said photosensitive strip a distance required by the projected character width, and

means for controlling said means to select and said means for advancing respectively in accordance with said input signals and said distance required by the projected character width,

said meansfor projecting include means for varying the size of said projected character images to produce a selectable range of point size images on said photosensitive strip,

said means for controlling include means for generating escapement signals proportional to the size of said projected character image for energizing said means for advancing to vary the distance required by the projected character width, and

said means for generating escapement signals include means for modifying said escapement signals independently of the size of said projected character image.

2. A phototypesetting machine for producing proportionally spaced type composition on a photosensitive strip, comprising:

means for providing input signals representing selected characters and control functions, means for carrying master character images, means to select desired character images from said means for carrying by strobing said character images with a pulse of light,

means for advancing said photosensitive strip a distance required by the projected character width,

said means for projecting include means for varying the size of said projected character images to produce a selectable range of point size images on said photosensitive strip,

said means for controlling include means for generating escapement signals proportional to the size of said projected character image for energizing said means for advancing to vary the distance required by the projected character width,

said means for controlling further includes switching means having three positions, said means for generating escapement signals further includes means for modifying said escapement signals in proportion to the size of said projected image and means for modifying said escapement signals independently of the size of said projected image, the first position of said switching means providing escapement signals determined in proportion to the size of said projected character image, the second position of said switching means providing escapement signals modified in accordance with e size 0 aid ro'ected ima e, the third osion of sai swiiehi ng means roai di ng escaper iient signals modified independently of the size of said projected character image.

3. A phototypesetting machine for producing proportionally spaced type composition on a photosensitive strip wherein characters are selected from a master character carrier and are projected to a photosensitive strip in different selectable size images, comprising:

means for advancing the photosensitive strip a distance required by the projection character width,and I said means for advancing including means for generating escapement signals and means for modifying said escapement signals independently of the size of said projected character image.

4. A phototypesetting machine as in claim 3 wherein said means for generating escapement signals further includes switching means having three positions, said means for generating escapement signals further includes means for modifying said escapement signals in proportion to the size of said projected image and means for modifying said escapement signals independently of the size of said projected image, the first position of said switching means providing escapement signals determined in proportion to the size of said projected character image, the second position of said switching means providing escapement signals modified in accordance with the size of said projected image, and the third position of said switching means providing escapement signals modified independently of the size of said projected character image.

5. A phototypesetting machine as in claim 3 wherein said master character carrier includes different character styles and different character widths for the characters of each character style further comprising means for sensing said character width, means for storing the sensed character widths, and means for delaying the transmission of said character widths from said master character carrier to said means for storing whereby the character width associated with each character is sensed.

Claims

1. A phototypesetting machine for producing proportionally spaced type composition on a photosensitive strip, comprising: means for providing input signals representing selected characters and control functions, means for carrying master character images, means to select desired character images from said means for carrying by strobing said character images with a pulse of light, means for projecting said selected character images onto said photosensitive strip, means for advancing said photosensitive strip a distance required by the projected character width, and means for controlling said means to select and said means for advancing respectively in accordance with said input signals and said distance required by the projected character width, said means for projecting include means for varying the size of said projected character images to produce a selectable range of point size images on said photosensitive strip, said means for controlling include means for generating escapement signals proportional to the size of said projected character image for energizing said means for advancing to vary the distance required by the projected character width, and said means for generating escapement signals include means for modifying said escapement signals independently of the size of said projected character image.

2. A phototypesetting machine for producing proportionally spaced type composition on a photosensitive strip, comprising: means for providing input signals representing selected characters and control functions, means for carrying master character images, means to select desired character images from said means for carrying by strobing said character images with a pulse of light, means for projecting said selected character images onto said photosensitive strip, means for advancing said photosensitive strip a distance required by the projected character width, means for controlling said means to select and said means for advancing respectively in accordance with said input signals and said distance required by the projected character width, said means for projecting include means for varying the size of said projected character images to produce a selectable range of point size images on said photosensitive strip, said means for controlling include means for generating escapement signals proportional to the size of said projected character image for energizing said means for advancing to vary the distance required by the projected character width, said means for controlling further includes switching means having three positions, said means for generating escapement signals further includes means for modifying said escapement signals in proportion to the size of said projected image and means for modifying said escapement signals independently of the size of said projected image, the first position of said switching meAns providing escapement signals determined in proportion to the size of said projected character image, the second position of said switching means providing escapement signals modified in accordance with the size of said projected image, and the third position of said switching means providing escapement signals modified independently of the size of said projected character image.

3. A phototypesetting machine for producing proportionally spaced type composition on a photosensitive strip wherein characters are selected from a master character carrier and are projected to a photosensitive strip in different selectable size images, comprising: means for advancing the photosensitive strip a distance required by the projection character width, and said means for advancing including means for generating escapement signals and means for modifying said escapement signals independently of the size of said projected character image.