US2555874A - Photolithographic plate inking, drying, and developing machine - Google Patents

Description

June 5, 1951 H. A. coUGHLlN PEOTOLITEOGRAEHIC PLATE INKING, DRYING, AND DEVELOPING MACHINE 4 SheeS-Sheet 1 Filed Deo. 25, 1946 June 5, 1.951

H. A. COUGHLIN PHOTOLITHOGRAPHIC PLATE INKING,

DRYING, AND DEVELOPING MACHINE 4 Sheets-Sheet 2 /4 LMVWM,

June 5, 1951 H. A. COUGHLIN 2,555,874

PHOTOLITHOGRAPHIC PLATE INKING, DRYING, AND DEVELOPING MACHINE Filed Deo. 23. 1946 4 Sheets-Sheet 3 FIG.13.

/795 H7- TOKA/Ens June 5, 1951 v H. A. COUGHLIN 2,555,874

PHOTOLITHOGRAPHIC PLATE INKING, DRYING, AND' DEVELOPING MACHINE Filed Deo. 25, 1946 4 sheets-sheet 4 Patented June 5, 1 .951

PHOTOLITHOGRAPHIC PLATE INKING, DRYING, AND DEVELOPING MACHINE Harry A. Coughlin, St. Louis, Mo., assignor to John S. Swift Co., Inc., St. Louis, Mo., a corporation of Missouri Application December 23, 1946, Serial No. 718,063

9 Claims.

In the manufacture of `photolithographic printing press plates, a zinc plate is coated with a solution of albumen and ammonium bichromate, which is sensitive to light when dry, and the matter to be printed is reproduced from a photographic negative onto the light sensitized plate by powerful electric light rays. The exposed, printing areas of the sensitized coating are hardened by the light and are insoluble in water, while the unexposed or non-printing areas of said coating are not hardened and are soluble in water.

In developing the exposed photolithographic press plates, the present practice is to pour a developing ink onto the sensitized coating, then spread the ink over said coating with a towel and then rub down the inked surface with a second towel to absorb the surplus ink and to dry the remaining ink. The inked plate is then placed in a pan of water or under a tap and the inked coating hand-rubbed with a large ball of cotton to soften and wash away the soft non-printing areas, leaving the hard printing areas aflixed to said plate.

This hand-inking and washing of the photolithographic press plate is a lslow and arduous operation, requires a large stock of rubbing towels and cotton and results in the loss of all of the developing ink absorbed by the towels. Another objection is that the hands become stained with ink dyes, which are diflicult to remove, inhalation of the chemical fumes causes sickness and loss of time; and physical contact with the ammonium bichromate causes serious poisonous infections which are difiicult to cure and cause some employees to seek new occupations.

It is an object of the present invention to provide an automatically operating photolithographic plate treating machine in which a plate or plates are automatically treated by a plurality of separate and distinct devices that are cooperatively associated together in the machine, and such devices perform diierent and successive individual functions on the plate or plates as the same are moving through the machine.

Another object of the present invention is to provide a photolithographic plate treating machine in which a plate or plates are automatically treated by a plurality of separate spaced-apart distinct devices which perform successive individual functions on the plate or plates as they are continuously moved through the machine.

lAnother object of the present invention is to devise a machine which will rapidly and efficiently ink,V dry and develop photolithographic press plates in one continuous operation without requiring the operator to touch the plate or be in close proximity thereto during such operations, thereby overcoming all of the objections associated with the hand inking and developing of such plates. Other objects are to provide for simplicity and cheapness of construction of said machine and for the automatic operation thereof. The invention consists in the automatic photolithographic press plate inking, drying and developing machine and in the parts and combinations and arrangements of parts hereinafter described and claimed.

In the accompanying drawings, which form part of this specification and wherein like symbols refer to like parts wherever they occur,

Fig. l is a plan view of an automatic photolithographic press plate inking, drying and developing machine embodying my invention,

Fig. 2 is a part side elevational and part vertical longitudinal sectional view of said machine,

Fig. 3 is a fragmentary horizontal sectional view on the line 3 3 in Fig. 2,

Figs. 4, 5, 6, 7, 8, V9, 10 and l1 are vertical crosssectional views taken on the lines 4 4, 5 5, 6 6, 1 1, 8 8, 9 9, I0 I0 and Il l l, respectively, in Fig. 2.

Figs. 12 and 13 are enlarged vertical cross-sectional Views through the developing head on the lines |2 l2 and l3 l3, respectively, in Fig. l0,

Fig. 14 is a perspective view of oney of the micro switches; and

Fig. 15 is a perspective flow chart, showing the Stations of the Vmachine and the electric control circuit therefor.

The photolithographic plate treating machine as embodied in this application is adapted to treat a' plate or plates automatically by separate and distinct devices which perform diierent successive individual functions on the plate or plates as they are continuously moved through the machine. These devicesspeciiically may consist of inking, heating and developing means and are usually arranged in that sequential order for the proper treatment of the plate. The machine includes power operated means `that is connected with each of the aforesaid devices and, additionally, with means for continuously moving the plate through the machine. Further, there is provided kindividual operating means, which means may be in the form of electrical switches or the equivalent thereof in an electrical circuit mounted on the machine adjacent each of the devices, whatever'they may be, and `operatively connects each of these devices with the power operating means and, specifically, such power operating means may consist of electric motor means in the electrical circuit. The aforesaid operating means is carried by the machine, of course, and each of these means is disposed in the path of movement of the plate and is operated by the .plate when the plate or plates are moving through the machine. In'providing such str-uctural features and arrangement as hereinbefore set forth, the operating means adjacent each of the devices serves to set into operation initially one of the devices and,before that device terminates its period of operation, another device is brought into operation .b y the next -operating means which also maintains the operation of the first treating device While the next device is in operation until after the plate has been treated by the first device lat which time the first device will be rendered inoperative. "Specically, the inking device may consist of a plurality of .superimposed .power driven rollers and the rollers preferably have agear associated with the same and the .diameter of the gear of each roller is substantially the diameterof the roller.

My automatic photolithographic printing press plate inking, dryingand developing machine comprises a suitable table I with yplate receiving, inking, heating and .developing stations A, B, C and D arranged in a row thereon .along the top thereof 'in the order named. The plate'receiving sta- .tion A is located at `the front end of the vtable vI and comprises a fixed horizontal top panel 2 adapted to receive and slidably support a yphotolithographic printing press plate `3 having a light sensitive top surface coatingof .albumen and vammonium bichromate (on which the matter that is lto .be printed has been photographically reproduced in the 'conventional manner vabove described. Journaled on 'the table :I at the dis- .charge end of thelpl'ate supporting panel 2 is a pair .of upper and lower cross rolls .4 and 15 in position to permit theleading edge of theplate 3 to be entered therebetween, "the upper roll VII operating as an idler hold-.down roll and the lower roll5 being power .driven'so asto feed said `plate to the inkingstation B.

The -plate inking station B comprises a fixed horizontal top panel 'I y'disposed in the plane of the top panel 2of the plate receiving station A, an ink fountain .or Itrough 8 Ydisposedcrosswise of the line of .plate fee'd and supported above the top panel 1 by means of upright supports 9 fixed 'to the table I, a 'multiplicity .of power driven rper-ipherally contacting ycross 'rolls `I0 journaled in said supports for transferring 'the developing ink from .said fountain to 'the :upper surface of vthe plate 3, and power VdrivenJfeed or pressure rolls II journaled in the Atable I and located in openings I2 provided therefor `in the top panel 1 immediately below the lowermost inking rollers and in position to engage theundersurface of said plate. As shown in the 'drawingsIthe feed rolls `II are spacedbelowthelowermost ink applying rolls I0 sofas `to prevent ink from'being applied to the back or under side ofthe plate.

The inked plate .3'moves from'the inking station B to the drying station C which comprises an endless feed belt I3'which vis supported at its receiving end on anidler cross'roll I.4'and at its delivery end on a .power driven roll l5, both rolls being journaled on'fthe table Ifand located so'that the upper stretch of said feed belt is located lin the plane of theplate supporting panel V'I of the inking station B. yI'heplate 3'is held down on the top `stretchcf the'feed belt I3 by'means of cross rolls I6 journaled in the table I above the belt supporting rolls or pulleys I4 and I5. The drying station B also includes a battery of overhead infra-red electric heat lamps I 'I that are supported in a frame IIa rising from the table and serve to dry the inked upper surface of the plate 3 as it passes through said station on the upper stretch of the endless belt conveyor I3.

The press plate 3 passes from the drying station C to the final or developing station D, which includes a stationary top panel I8 for supporting said plate in the plane of the top stretch of the conveyor belt I3 of said drying station, a pair of spray .pipes IIS disposed above and crosswise of the said paneladjacent to the plate receiving -endfthereof for delivering a spray of water onto the upper surface of said plate as it passes beneath said pipes, and a horizontally movable developing cross head 20 which engages the upper surface of said plate between said spray pipes and the delivery end of said panel. The spray pipes I9 and developing Vvhead 2U are supplied'with water from a suitable pipe line 2| containing-a normally closed electrically operated cut off valve 22 and including a flexible sectionl connected to said developing head so as to permit bodily movement thereof. The water discharged from the spray pipes I9 and the developing head flows through drain openings 24 inthe plate supporting panel I8 of 'the developing station'D and over the edges of said panel into a drain tank 25 supported therebelow on a shelf 26 formed in the table I and is discharged fromsaid tank through a suitable drain pipe 21.

The developing station also includes a power driven feed roll 28 journaled in the table I crosswise thereof and located in an opening `29 4provided therefor in the panel I8 .between the spray pipes AI9 and the'developing-head 2U and in position to contact the underside of the press plate ..3 and move it along said panel. Thev plate .3 is held down on the feed roller 218and the top panel I8 by means of an idler roller 30 journaled yin the table I. Upper and lower idler rolls3I are journaled in the table crosswise thereof yadjacent to the delivery end of the ytop panel I9 .of lthe developing'station with lthe lower roll located in an opening 32 in said panel in position to afford rolling support for the plate 3 and with the lower roll in position to hold the plate down .on the lower roll and on said panel.

The feed roll -5 at the receiving end of the plate receiving station A and the feed rolls Il of the inking station B are all driven `by `a normallyfinoperative .electric motor 33 mounted on the shelf 25 .beneath the receiving station. The driving connection between the motor v33 andthe feed rolls 6 and Il'comprises a driving belt connection 34 between said motor :and .a shaft 35 journaled in a bearing 36 on the motor supporting shelf 26, a sprocket chain connection between said shaft and a driven shaft-38 that is journaled in the table longitudinally thereof and has-a worm and worm gear connection 39 with the feed roll '6 and similar driving connections 40 with the feed rolls II. The feed rolls Il also 'have drive gear connections 4I with lthe lowermost ink applying rolls of the inking station B. Byreference to Fig. 6 of the drawings, it Vwill'be seen that `the diameter of the gears 4I is substantially equal to the diameter of the rollers to which these gears are attached.

The feed belt I3of thedrying -station C and the feed roll 28 land developing head 20 of the developing station'D `are operated by a normally inoperative electric motor 42 supported beneath thev receiving station on the shelf 26 of the table I. The electric motor 42 has a driving belt connection 43 with a horizontal shaft 44 journaled in a bearing 45 on the shelf 26, a sprocket chain connection 46 between said shaft and a horizontal shaft 41` that extends rearwardly beneath the inking and drying stations and is journaled in bearings 48 mounted on said shelf. At its rear end, the shaft41 has a sprocket chain connection 49 with the front end of a horizontal shaft' 50 disposed longitudinally of the table and journaled in bearings 5I thereon. 'The front end of the shaft 5I) also has a sprocket chain connection 52 with a shaft 53 supported alongside thereof in bearings 54 on the table I. The shaft 53 extends beneath the driving roll or pulley I5 for the delivery end of the feed belt I3 of the drying station C and the feed roll 28 of the developing station D and has a worm and worm gear connection 55 with said driving roller of said belt and a similar worm and worm gear connection 56 with said feed roller.

J ournaled in bearings 51 fixed to opposite sides of the table I are vertical shafts 58, that are simultaneously driven in the same direction through bevel driving gear driving connections 59 between their lower ends and a cross shaft 6I) journaled in bearings 6I in the table I, one oi said bevel gear driving connections being driven from the shaft 50 by a bevel gear 62 xed to the `rear end thereof. The vertical shafts 58 terminateat their upper ends in crank disks 63 provided'with upstanding eccentric crank pins 64 that are linked together by a cross connecting bar 65 whose ends seat on said disks and have vertical openings in which said pins are journaled, whereby said cross bar is moved back and forth crosswise of the machine by the rotary motion of said crank disks. The above developing head 2i) comprises a hollow elongated body that issuspended from the crank connecting bar 65 lengthwise thereof for movement therewith by means of inverted channel-shaped straps 66 that are fixed lto the top of said head and straddle said bar and are supported thereby by thumb screws 81 that are threaded through the top of said straps with their lower ends seated on the top of said bar. The straps 56 seat in vertical'grooves 68 in the sides-of the bar 65 and thus force the developing head 20 to move therewith. The hollow developing head 20 is supplied with water through the flexible hose 2Ia and has a flat bottom with a multiplicity of discharge openings or perforations 69 therein; and the perforated bottom of said container is covered with a porous rubbing pad 1U which extends upwardly around the sides of the container and is clamped to the top thereof by means of clamping plates 1I.

' The two electric motors 33 and 42, the infra-red lamps I1 and the electrically operated valve 22 in the water liney 2| are controlled by normally closed micro electric switch devices contained in four switch boxes 12, 13, 14 and 15, mounted on the table, each box having pivoted thereon a bell crank lever 16 with a roller 11 adapted to be actuated by the movement of the press plate 3 therebeneath to open the switch or switches associated therewith. The switch box .12 is located near the delivery end of the receiving station A and contains a singlenormally closed switch 12a; the box 13 is located near the delivery end` of the inkingstation and .contains two vnor-v f mally closed switches 13a and 13b;` the box 14 is located near the delivery end of the heating station C and contains three normally closed switches 14a, 14b and 14C; and the box 15 is located near the delivery end of the developing station D and contains two normally closed switches 15a and 15b.

The switches are located in an electric control circuit which is supplied by two service wires 18 and 19, the wire 18 being provided with a manually controlledpush-button cut-off switch which may be mounted on one side of the table I adjacent to the receiving end thereof. Aline 8| leads from the Service wire 18 to one side of the switch 12a; and a line 82 leads from the other service wire 19 to the motor 33 and thence to the other side of said switch and to one side of the switch 13a, the other side of which is connected through a line 83 with the service wire 19. One side of the switch 13b is connected by a line 54 to the service wire 18; and a line 85 connects the other side of said switch with one side of the switch 142L and also leads to one side of the circuit for the battery of heat lamps. A line 8B leads from the service wire 18 to the other side of the switch 14a; and a line 81 leads from the other service wire 19 to the other "side of the lamp circuit.

.A line 88 leads from the service wire 19 to the motor 42 and thence to one side of each of the switches 14b and 15a. A line 89 leads from the other service 'wire 18 to the other side of the switch 141, `and a line 90 connects said service wire with the other side of the switch 15a. A line SI leads from the service wire 19 to the electrically operated stop valve 22 and thence to one side of each of the switches 14c and 15b. A line 92 leads from the service wire 18 to the other side of the switch 14C, and a line 93 leads from said service wire to the other side of the switch 15b.

^ After the matter to be printed is reproduced on the sensitized coating of the press plate 3, this exposed plate is placed atwise on the top panel 2 of the receiving station A with the sensitized coating facing upwardly. The plate is then slid rearwardly on the panel 2 until the leading edge of the plate first passes beneath the roller 11 of the switch actuating lever 1|6 of the switch box 12 and then into position to be engaged on its under side by the feed roll 5 at the delivery end of said receiving station. This movement of the plate kactuates the lever 16 of the switch box 12 and closes the switch 12a therein, thereby establishing a closed circuit between the service wires 18 and 18 and the motor 33 through the lines I8| and 82 and thus starting said motor and the rotation of the feed roll y5 at the discharge end of the receiving station A, and the inking rolls I0 and feed rolls II of the inking station B. The plate is then fed by the feed rolls I!! and II through the inking station B where the coated upper surface of the plate is given a uniform coating of developing ink.

The leading edge of the ink coated plate 3 then engages the switch operating arm 1'6 of the switch box 13 at the discharge end of the inking station, thus closing the two switches 13e and 13b in said box before said plate has traveled far enough to permit the switch 12a to open. The closing of the switch 13a establishes a holding circuit for the motor 33 after the plate has traveled far enough to permit the switch 12a to open, this holding circuit being established through the lines 82 and 83, while the closing of the switch 13b.establishes a circuit to the battery of infrared lamps I1 through the lines 84 and 85, .thus bringingsaid lamps into `operation to thoroughly dry the coating of developing ink .on the upper surface of the plate passing .therebeneath The leading edge of the .plate 3 then engages the .switch .operating lever .16 .of the'switch box .'14 at the discharge end of inking :station.B, 'thus closing the three switches 1425.111la and .Fl4vitherein before .said .plate .has traveled far enough to permit `the lamp circuit .switch 13b to open. .The closing of A.the switch .'14a establishes a holding circuit for the lamps .H after the plate has traveled far enough to .permit the switch '13b to open, this holding .circuit 'being .established throughthe lines 81, .85 .and .86. The closing of .the .switch Mb establishes a circuit to the second rmotor 42 through .the lines 88 'and .89, thus starting said motor and the operation .of the feed abelt I3 :of the Adrying station C and the .feed roller .28 and the developing head 20 of the developing station D. The closing of the switch 'I4c establishes a circuit to the valve 22 through the lines 9| .and -92thus causing said Valve to open and 1water `to flow tothe spray .pipes 'I9 and the operating developing head 2G of the developing station where the plate is thoroughly `washed and developed.

The leading edge .of .the vplate .then lengages the switch operating arm T6 ofthe switch box 'l5 atpthe discharge Aend ofthe developing station D, thus vclosing the two switches '15e-.and '15b in said box ybeforethe plate has traveled far enough to permit the motor circuit switch 'I4b andthe valve circuit switch 14C'toopen. `The closing .of switch 'l5a establishes a holding circuit for the motor 42 through the lines 88 and 9@ and the closing. ofthe switch 15b establishes a holding "circuit for the valve 22 through the lines 9| and`93. When Ythe trailing edge of the developed plate passes `from beneath the actuating roller H of the fourth and final switch box 15, both switches .'15a and 15b open, .thus causing the valve 22 to close and .lout .off the flow of water to the spray pipes i9 and the developing head and the motor 42 'to cut off .and stop the operation of the feed belt I3, the feed roll 28 and the developing-head 2.0.

In accordance with common practice,the .developed plate is then semi-dried and :the printing surface thereof etched with .'acidand Ithen sponged with liquid `gum arabic. Asa result .of this combination etching and gumming, thefnonprinting areas are protected from oxidation and will not take ink, while the greasy. acidzresisting printing areas are receptive to ink.

The hereinbefore described automatic photolithographie printing 4press plate inking, drying and .developing machine has numerous important advantages. It provides meansfor quicklyinking, drying anddeveloping the plate in one continuous .process without requiring the .plate to-be handled duringthe inking :and developingoperations and thus'entirely eliminates the rmanual labor heretofore required in performing said operations. It also dispenses with and saves the .cost Vof the rubbing 'towels and cotton heretofore employed in the inking and developing operations; and it also more uniformly distributes the developing ink over the surface .ofthe plate and results in a material saving in the amount .of ink. The plate is sprayed with water to softenfthe unexposed area of the coating before it is engagedby the developing head; and the rubbing action of said head on thesoftened areas quickly removes them and the developing ink attached thereto vfrom the plate, leaving .the `hard exposed printing areas affixed tothe plate .in clear :black designs. An-

other `advantage :of jthe above .machine is that it is very .economical .of electricity and water randilabor. The `.above .machinealso :has .the great advantage of eliminating `the .serious .infections and chromatic poisoning which heretofore causedxlossaof time by the .operator and the-operatortoabandon his trade; .and italso does `not require .the operator .to be close enough to the work .duringjinkng drying and developing .operations to'be subject to the nauseatngeifect of the chemical vapors.

Obviously, v.the hereinbefore described construction .admits of considerable'modication without departing from the invention. Therefore, I .do not wish .to be limited to 4.theprecise arrangement shown :and described.

What I claim is:

1. A photolithographic Aplate treating machine in which .the :plate is automatically treated by za plurality .of .spaced-apart separate and ldistinct devices ywhich perform different Asuccessive .individual functions on the plate .while the plate is continuously moved through the machine, .the said devices being mounted on the machine in their spaced relationship, means for continuously moving the plate through the machine, power operated means connected independently with eachIof'the devices and with the means for continuously moving lthe plate through vthe machine foroperatingsame, operating Vmeans .adjacent one device forinitiating operation of that particular device, operating .means adjacent another of the devices'for.initiatingoperation of another of the .devices and .for continuing operation Aof .the Yoperating device, operating means for initiating operation of still another of the devices .and continuing .operation of one vof .the operating devices, and operating'means adjacent the .device vat the final stage of .treatment for discontinuing'operation of the machine.

2. A photolithographic plate treating machine as defined in and by claim 1 wherein thepower operated means consists of electric motor means in an electrical circuit.

3. A photolithographicplate treating machine .as defined in and by :claim l wherein the operatin g means are in an electrical circuit.

4. A lphotolithorgraphic plate treating machine as defined in and by claim l wherein the power operated means consists of electric motor means in an electrical circuit and the operating means is also inthe electrical circuit.

i5.. A photolithographic plate treating machine as defined in and by claim 4 in which the operating means are electrical switches.

6. A photolithographic plate treating machine as .dened in and by claim 1 wherein the devices are inking, heating and developing devices respectively.

'7. A photolithographic plate treating machine as defined in and by claim 1 wherein the power operated means is electrical motor means and the .operating means are electrical switches, and the devices .are inking, heating and developing devices respectively, and the motor means and the switches all being in an electrical circuit.

8. Aphotolithographic plate treating machine as defined in and by claim 1 wherein vthe devices are inking, heating and developing devices respectively, the inking devicecomprising a plurality .of superposed power driven rollers.

.9. A photolithographic plate treating machine as defined in Yand by claim 8 wherein the rollers are .gear drivenand .the diameterv of each gear is substantially equal to the diameter of each of Number Name Date the rollers. 1,640,961 Pinckney Aug. 30, 1927 HARRY A. COUGHLIN. 1,908,487 Powers May 9, 1933 2,036,232 Kinzler Apr. 7, 1936 REFERENCES CITED 5 '2,114,723 Paasche Apr. 19, 1938 The following references are of record in the 2221776 Carlson n NOV' 19 1940 me of pai-lent: Erz June 30, 2,325,867 Matsakas Aug. 3, 1943 UNITED STATES PATENTS 2,343,975 Hoseld M5114, 1944 Number Name Date 10 l2,347,511 Scarzello Apr. 25, 1944 1,509,725 Freer 55151.23, 1924 2,434,942 M agee Jan 27, 1948 1,523,571 Wolfe Jan 20I 1925 2,442,407 GlbbOnS June 1, 1948 1,591,436 Salins July 6, 1926

Claims (1)

1. A PHOTOLITHOGRAPHIC PLATE TREATING MACHINE IN WHICH THE PLATE IS AUTOMATICALLY TREATED BY A PLURALITY OF SPACED-APART SEPARATE AND DISTINCT DEVICES WHICH PERFORM DIFFERENT SUCCESSIVE INDIVIDUAL FUNCTIONS ON THE PLATE WHILE THE PLATE IS CONTINUOUSLY MOVED THROUGH THE MACHINE, THE SAID DEVICES BEING MOUNTED ON THE MACHINE IN THEIR SPACED RELATIONSHIP, MEANS FOR CONTINUOUSLY MOVING THE PLATE THROUGH THE MACHINE, POWER OPERATED MEANS CONNECTED INDEPENDENTLY WITH EACH OF THE DEVICES AND WITH THE MEANS FOR CONTINUOUSLY MOVING THE PLATE THROUGH THE MA-

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