US2780154A

US2780154A - Photographic printing machine

Info

Publication number: US2780154A
Application number: US282650A
Authority: US
Inventors: Musho Peter
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-04-16
Filing date: 1952-04-16
Publication date: 1957-02-05
Anticipated expiration: 1974-02-05

Description

P. MUSHO PHOTOGRAPHIC PRINTING MACHINE Feb. 5, 1957 Filed April 16, 195; 2 sheets-sheet 1 @i i: v

array/V516.

Feb 5, 1957 P. Musi-io 2,780,154

PHOTOGRAPHIC PRINTING MACHINE United. States Patent i PHOTOGRAPHIC PRNTING MACHINE Peter Musho, Wyandotte, Mich.

Application April 16, 1952, Serial No. 282,65)

5 Claims. (Cl. 95H75) This invention relates to. automatic photographic printing machines.

In commercial photography it frequently is necessary to make a relatively large number of prints from a single negative, and there is a current need and pressing demand for a machine capable of making a large number of prints of uniform fine quality in rapid succession.

lt is an important object of this invention to provide a machine of this character that is capable of printing photographs rapidly and in quick succession.

Another object of the invention is to provide a photographic printing machine having novel means for holding the sensitized paper on the negative which results in a print of unusual excellence.

Still another object of the invention is to provide a photographic printing machine which operates automatically to make the desired number of prints and that can be readily adapted by conventional means to shut down automatically after the desired number of prints have been made.

Yet another object of the invention is to provide a photographic printing machine that can be readily adapted to accommodate prints of varying sizes.

A further object of the invention is to provide a photographic printing machine that can be readily adapted to compensate for variations in film density.

Other objects and advantages of the invention will be apparent during the course of the following description.

ln the drawings forming a part of this specification and wherein like numerals are employed to designate like paits throughout the same:

Fig. l is a side elevational view, having parts broken away and shown in section, of a photographic printing machine' embodying the' invention and illustrating the platen of the machine fully lowered to hold the sensitized paper solidly and iiatly against a negative being printed;

' Fig; 2 is an endl elevational view of the machine;

Fig. 3 is a vertical sectional view taken on the line 3-3of Fig. l;

Fig. 4 is a vertical sectional view taken onthe line 4--4- ofv Fig. 3 but showing the platen fully raised and disengaged from the sensitized paper; and

Fig. 5LV is a diagrammatic View showing an electrical circuit forming a part of the machine;

l-n the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral lildesignates a printing box carried by a suitable supporting framework 12 which preferably holds the box. elevated. and at a height convenient to the operator of the machine. A plurality of electric lamps 14 are mounted within and on the bottom of the box 1i). Any suit-able number of lamps may be employed and they may be arranged and spaced relative to each other according to the exigencies of the particular situation. Four lamps 14 are. here shown and they are arranged in a generally rectangular pattern in the box l). As shown in.Fig,. 5, the four lamps 14 are electrically connected in parallel and the individual circuit of each lamp is 2,780,154 Patented Feb. 5,v 1957 2 provided with a rheostat 16 which controls the ow of current to the lamp. The two main leads 18 and 20 of the circuit are adapted for connection to any suitable source of electrical energy, and a normally open microswitch 22 provided in the lead Ztl controls energization of the entire circuit. By selective manual positioning of the rheostats la, the brightness of the individual lamps can be easily adjusted and the amount of light in different parts ot` the box can be easily controlled. The

opposite sides

24 and 26 of the box 1) are removable to provide ready access to the lamps 14 and control rheostat l and the removable sides normally are held closed by screws 28. An opening 3i) is provided centrally in the top of box lil and the opening is closed by a suitable transparent glass or window 32 which preferably is recessed into the. top around the opening so that the top of the glass extends substantially flush with the top of the box.

ln operation of the machine, a negative 34 to be printed is placed. on the glass window 32, and the negative is held in place in any suitable manner as by means of adhesive strips 35. Light from the lamps i4 is diffused by a frosted glass 38 disposed horizontally above the lamps and on a suitable supporting ledge dii.

Fastened to the supporting framework l2 at one side thereof are laterally spaced brackets li2 which support a roll' 44 of sensitized photographic paper. ln use, the sensitized paper extends from the roll 44 across the printing box it) as shown in Figs. l and 4. it will be readily appreciated in this connection that the paper is arranged to extend over the negative 34, and as the paper moves from the negative it passes between a pressure roll 46 andv a feed roll fr?, mounted between brackets Si) on and upstanding from the trame 12. The pressure roll 46 preferably is of hard rubber and the feed roll 48 preferably is of relatively soft rubber. The feed roll 4S is rotatably driven as hereinafter described, and as the rollers rotate they draw the paper across the printing box 10 and along the negative 34 being printed.

in order to obtain prints of finest quality it is necessary to hold the sensitized paper in more or less uniformly pressed engagement over the entire area of the negative and to hold the negative absolutely flat during exposure of the print. To this end i have experimented with a wide variety of materials having varying degrees and kinds of resiliency for pressing the print against the negative. Among the materials and devices tested were felt, sponger rubber, hard rubber, and mechanically operated spring-loaded pressure plates. None of these expedients, however, produced a really high quality print. Apparently negatives vary in thickness and none of the con trivances referred to specifically above proved capable of holding the print absolutely flat against the negative over its entire surface.

I have now discovered a platen construction. that is pre-eminently satisfactory and which produces prints having maximum brilliance and detail. The platen, here designated by the numeral 52, comprises a ila't, generally rectangular backing plate or board Sd and superposed pads S6 and S8 of sponge rubber and hard rubber respectively adhesively or otherwise secured on the undersurface of. the backing plate. The undersurface of pad 58'- is wailed to provide ay multiplicity of individual projections 6*? over the entire surface or" the pad. As shown in the drawings, the platen 52 is arranged above the printing boxV 1d and parallel to the top thereof with the pad 58 positioned directly above the window 32, and it will be observed that the pad 58 is suiciently large to cover the window and the negative 34.

Platen 52.V is held in proper' position with respect to the printing box. 1t). by lateral. projections 62 on the backing plate 54, which projections extend into vertically arsonea elongated slots 64 in upright standard 66 bolted or otherwise fastened to the printing box at opposite sides thereof. Also, the interengaging projections 62 and slots 64 guide the platen during vertical movement thereof relative to the box 10. Leaf springs 68 interposed between the box 10 and platen 52 and fastened at one end to the box hold the platen normally raised from the Window 32 so as to permit a negative 34 to be readily mounted and attached for printing and to permit the sensitized paper to be easily threaded between the negative and the platen 52.

-ln use the platen 52 is pressed downwardly against the resilient action of springs 68 to hold the sensitized paper 44 atly against the negative 34 and to hold both the paper and the negative absolutely fiat against the win-V dow 32. When the platen is pressed downwardly with substantial force in the manner described, the projec tions 60 individually engage the sensitized paper at a plurality of more or less uniformly spaced points and each projection exerts an individual force against the paper. However, downward pressure exerted against the platen also causes the individual projections 60 to flatten out so that they merge or substantially merge with each other; and when this occurs, substantially the entire surface of the print is engaged by the pad. As a consequence, the pad compensates for variations in thickness of the negative and holds the sensitized paper absolutely fiat and in pressed intimate engagement with the negative over its entire area, resulting in maximum sharpness and brilliance in detail in the finished print. The soft sponge rubber pad 56 also is compressed when downward pressure is exerted against the platen, and this pad apparently spreads and distributes the pressure more or less uniformly against the entire surface area of the bottom pad 58. rl`he eye of a skilled technician can readily detect a difference in quality between prints produced by the combination of pads 56 and 58 here shown and prints produced by either of these pads alone.

The present invention provides mechanical means for operating the platen 52, and this means comprises a motor 70 connected by 'an endless belt 72 to the input shafft 74 of a speed reducer 76. The output shaft 78 of the gear reducer 76 is suitably coupled to a shaft 80 which is journaled in bearings 82 at the upper ends of supports 66. Fastened to the shaft 80 is a transverse arm 84 fably is provided with suitable bearings (not shown) for L substantially frictionless rotation. The pairs of rollers 86a and 86h of course revolve around the shaft 80 when the latter is rotated. As each set of rollers traverses the bottom segment of its orbital path, the rollers engage spaced parallel leaf springs 90 on the platen 52. One end of each leaf spring 90 is fastened to the platen by a rivet 92 or the like (-lig. l) and the other end thereof is free to slide on the platen so that the springs tend to flatten when engaged by the rollers.

In the particular arrangement shown, the platen 52 is operated twice rduring each rotation of the shaft 80. It will be readily appreciated, however, that any desired number of platen actuators can be used. Under certain conditions it may be desirable to use only one set of platen actuators on the shaft 80 so lthat the platen is operated only once for each rotation of the shaft. On the other hand, it may be desirable under different circumstances to employ more than two platen actuators so that the platen is operated a relatively greater number of times for each rotation of the shaft 80.

The drive mechanism also includes means for pulling the sensitized paper 46 under platen 52 in proper timed relation with the platen operating means. This mechanism comprises a segmental gear 94 on the shaft 80 and arranged to mesh with a driven gear 96 keyed or otherwise fixed to a shaft 98 journaled for rotation on a suitable support 100. Also keyed on the shaft 98 for mutual rotation with the gear 96 is a second gear 102 which is drivingly connected by an endless chain 104 to a sprocket 106 on the shaft 108 of the feed roll `48. The segmental gear 94 has two gear segments 94a and 9411, and the gear segments are arranged at right angles to the platen operating rollers 86a and 86h. @It will be readily apparent that gear 96 (and consequently the feed roll 48) is driven only when engaged by one or the other ot gear segments 94a and 94h and that the feed roll 48 is idle when the gear segments are out of engagement with the driven gear 96 as shown in Fig. 1.

In operation, a negative 34 to be printed is first mounted on the printing box 10 in the manner hereinabove described and the sensitized paper 44 is inserted under the platen 52 on top of the negative. 11n the interest of economy a suitable leader preferably is fastened to the sensitized paper and threaded between the drive and pressure rolls 48 and 46. The operation is then begun by starting the motor 70 to rotatably drive the shaft 80.

The parts are positioned as shown in Fig. 4 at the beginning of the operating cycle with rollers 86a about to engage the leaf springs 98 and the gear segment 94a just disengaging the driven gear 96. As the rollers 86a move against the springs 98 they push the platen 52 downwardly to press the sensitized paper 44 and the negative 34 absolutely flat in the manner hereinabove described. During this action the

leaf springs

68 and 90 absorb the initial impact of the rollers 86a and the springs 90 gradually transmit the driving force of the rollers to the platen 52. The leaf springs 68 atten and extend across the top of the printing box 18 as the platen 52 is pushed downwardly.

The limit switch 22 conveniently may be mounted in the path of one leaf spring 68 (Fig. 4) so that the leaf spring closes the switch and illuminates the lamps 14 as the platen approaches the fully lowered position shown in Fig. 1. Manifestly, the length of exposure can be regulated by adjusting the switch 22 relative to the actuating spring but, for any given position of the switch, the exposure is controlled by the time intermediate gear 94 is out of mesh with the driving gear 96. Thus the exposure is controlled also by the size of gear 94. Minor variation in exposure can, of course, be made by judicious adjustment of the rheostats 16.

As the' rollers 86a rotate past the position shown in Fig. 1 and in the direction of the arrow, they gradually release the platen 52 and permit leaf springs 68 to raise the platen from the sensitized paper 44. During the portion of the operation described above, the gear 94 does not engage the driven gear 96 so thatV the feed roll 48 is idle.

Substantially immediately after the platen 52 releases sensitized paper 44, however, the segmental-gear 94h en gages gear 96, and the feed roll 48 is rotatably driven to advance the strip of sensitized paper 44 across the negative. Paper 44 continues to be fed under the platen in this manner until the segmental gear 94h disengages gear 96. During this phase of the operation both sets of rollers 86a and 86b are out of engagement With the platen 52. As the segmental gear 94h disengages gear 96 the other set of rollers @6b is positioned to engage the platen 5 2 as shown in Fig. 4 and the cycle of operation y is repeated.

From the foregoing it will be readily apparent that the sensitized paper 44 and platen 52 are operated alternately in quick succession. The plate 52 is pushed downwardly and the print is made when the feed roll 48 is idle and the latter is operated to advance the sensitized paper suiciently to bring an unexposed section of the paper over the negative as when the platen is raised. The machine is capable of operating very rapidly in this manner and almost perfect prints have been made at a rate of about thirty a minute. It would appearv that even more rapid operation is possible. Important advantages are achieved by using segmental gears to drive the feed roll 48. For instance, it is possible to regulate the length of sensitized paper moved during each operation of the machine by varying the gear ratios in the gearing which drives the feed roll d8. Also, by selectively, controlling: the gear ratios it is possible to regulate the dwell between operations of the feed roll and thus the time available for printing. The length of sensitized paper 4d Athat must be moved between printing operations of course depends upon the size of the picture being printed and this same factor assures to some extent the length of time required for printing. ln general, larger pictures require a longer printing time than relatively smaller pictures. Variations in film density are readily compensated by adjusting the rheostate 16.

Having thus described the invention, I claim:

l. In a photographic printing machine, a printing box having a transparent Window forming a support for a negative to be printed; means for guiding a strip of sensitized paper over a negative on said window; means for drawing said paper over said negative; a platen mounted above the window for movement relative thereto adapted to press said paper against said negative during printing; and means for actuating said paper-drawing means and said platen alternately comprising a rotatably driven shaft, a segmental gear fixed to and rotatable with said shaft, a gear driven intermittently by said segmental gear, `means operable by said `driven gear for actuating said paper-drawing means intermittently, a normally arched leaf spring surmounting and fastened at one end to said platen, a radial arm on and rotatable with said drive shaft, and roller means on the end of said arm engageable with said leaf spring during rotation of said arm to depress the spring on the platen and to move the platen into pressed engagement with said paper, said arm positioned on the shaft to bring the roll into engagement with the spring during the time interval when said paper-drawing means is inoperative.

2. In a photographic printing machine, a printing box having a transparent window forming a support for a negative to be printed; means for guiding a strip of sensitized paper over a negative on said window; means for drawing said paper over said negative; a platen mounted above the support for movement relative thereto adapted to press said paper against said negative during printing; and means for actuating said paper-drawing means and said platen alternately comprising a rotatably driven shaft, a segmental gear xed to and rotatable with said shaft, a gear driven intermittently by said segmental gear, means operable by said driven gear for actuating said paper-drawing means intermittently, a radial presser arm on and rotatable with said drive shaft, a roller on the end of said arm engageable periodically with said platen during rotation of said arm to move the platen against said paper, a normally arched leaf spring surmonnting and fastened at one end to said platen positioned for engagement by said roller, said spring adapted to absorb the initial impact of the roller and to transmit the driving force of the presser arm gradually to the platen as the latter is moved into pressed engagement with said paper, said presser arm being positioned on the shaft to bring the roller into engagement with said spring during the time interval when said paper-drawing means is inoperative; and an electrical circuit including lamp means in said printing box and a normally open switch for controlling flow of electrical current to said lamp means arranged for engagement with and adapted to be closed by parts of the machine when the platen is depressed by said roller.

3. In a photographic printing machine, a printing box having a transparent window forming a support for a negative to be printed; means guiding a strip of sensitized paper over a negative on said window; means for drawing said paper over said negative; a platen mounted on the box above said window; leaf springs supporting the platen holding the latter normally raised from the box but yieldable to permit movement of the platen against said window to press said paper against said negative during printing; means for actuating saidv paper-drawing means and said platen alternately comprising a rotatably driven shaft, a segmental gear fixed to and rotatable with said shaft, a driven gear intermittently engageable with said segmental gear, means operable by said driven gear for actuating said paper-drawing means intermittently, a normally arched leaf spring surmounting and fastened at one end to said platen, a radial presser arm on and rotatable with said drive shaft, a roller on the end of said arm engaging said last-mentioned leaf spring periodically during rotation of said arm to depress the spring on the platen and to move the platen into pressed engagement with said paper, said arm positioned on the shaft to bring the roll into engagement with the spring during the time interval when said paper-drawing means is inoperative; and an electrical circuit including a plurality of lamp means connected in parallel circuit within said printing box; a rheostat in each individual lamp circuit for controlling the intensity of light from said lamp, and a normally open switch for controlling the flow of electrical current to said lamp means mounted on said printing box for engagement by one of said leaf springs when the platen is depressed by said roll.

4. in a photographic printing machine, a printing box having a transparent window forming support for a negative to be printed; means for guiding a strip of sensitized paper over a negative on said window; means for drawing said paper over said negative; a platen mounted above the window and moveable relative thereto; a soft sponge rubber pad on the undersurface of said platen; a hard rubber pad on the undersurface of said sponge rubber pad, said hard rubber pad having a multiplicity of closely grouped, depending, relatively elongated and flexible projections individually engageable with said paper and collectively operative to press the same against said negative during printing; and means for actuating said paper-drawing means and said platen alternately comprising a rotatably driven shaft, a segmental gear fixed to and rotatable with said shaft, a rotatably driven gear mounted for in termittent interengagement with said segmental gear, means operable by said driven gear for actuating said paper-drawing means intermittently, and means actuated by said rotatably driven shaft for moving said platen into pressed engagement with the paper during the time inter vals when said paper-actuating means is inoperative.

5. ln a photographic printing machine, a printing box having a transparent window forming a support for a negative to be printed; means for guiding a strip of sensitized paper over a negative on said window; means for drawing said paper over said negative; a platen mounted above the window for movement relative thereto; a soft sponge rubber pad on the undersurface of said platen; a hard rubber pad on the undersurface of said sponge rubber pad, said hard rubber pad having a multiplicity of closely grouped, depending, relatively elongated and flexible projections individually engageable with said paper and collectively operative to press the same against said negative during printing; means for actuating said paper-drawing means and said platen alternately comprising n rotatably driven shaft, a segmental gear fixed to and rotatable with said shaft, a rotatably driven gear mounted for intermittent engagement witli said segmental gear, means operable by said driven gear for actuating said paper t, ving means intermittently, and means actuated by said rotatably driven shaft for moving said platen into pressed engagement with the paper' during the time intervals when sa'd paper-actuating means is inoperative; a normally arched leaf spring surmounting and fastened at one end to said platen; a radial presser arm on and rotatable with said drive shaft; and a roller on the end of said arm engaging said leaf spring during rotation of said arm to depress the spring on the platen and to move the platen into pressed engagement with said paper, said arm positioned on the shaft to bring the roll into engagement with the spring during the time interval when said paper-drawing means is inoperative.

References Cited in the le of this patent 8 Kesses May 30, 1922 Hopkins June 9, 1931 Manzotti May 10, 1932 Pupke Nov. 5, 1935 Weiss Sept. 2, 1941 Wolters Dec. 14, 1943 Grover Mar. 14, 1944 Jacobson May 27, 1947 Leavitt Dec. 12, 1950 FOREIGN PATENTS Germany Nov. 3, 1887 Great Britain of 1901