US3136237A

US3136237A - Photographic printing and developing apparatus

Info

Publication number: US3136237A
Application number: US132747A
Authority: US
Inventors: Moon William Richard Harding
Original assignee: Hall Harding Ltd
Current assignee: Hall Harding Ltd
Priority date: 1961-08-21
Filing date: 1961-08-21
Publication date: 1964-06-09
Anticipated expiration: 1981-06-09

Description

June 9, 1964 3,136,237

PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS W. R. H. MOON 9 Sheets-Sheet 1 Filed Aug. 21, 1961 w. R. H. MOON 3,136,237

PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS June 9, 1964 9 Sheets-Sheet 2 Filed Aug. 21, 1961 June 9, 1964 w. R. H. MOON 3,136,237

FHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS Filed Aug. 21, 1961 9 Sheets-Sheet 3 June 9, 1964 w. R. H. MOON 3,136,237

PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS 9 Sheets-Sheet 4 Filed Aug. 21. 1961 June 9, 1964 w. R. H. MOON 3,136,237

PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS 9 Sheets-Sheet 5 Filed Aug. 21, 1961 J1me 1964 w. R. H. MOON 3,136,237

PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS Filed Aug. 21, 1961 9 Sheets-Sheet 6 RELEASE PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS Filed Aug. 21, 1961 June 9, 1964 w. R. H. MOON 9 Sheets-Sheet 7 1 7 I 10 01 6 0 X 0 m g m 5 f 5 0 v l 7 a I 1 6 2 6 W 1 1 2 0 1 a u, 1 a .5 4 0/ a 2 a 5 0 1. 1 m Ta w J J O u. h Aw ll. MU a 2 y l June 9, 1964 w. R. H. MOON 3,136,237

PHOTOGRAPI-IIC PRINTING AND DEVELOPING APPARATUS Filed Aug. 21. 1961 9 Sheets-Sheet 8 I H @R'; 4 X

l 92 ft 11/ g 95 [fly/a June 9, 1964 w. R. H. MOON 3,136,237

PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS Filed Aug. 21, 1961 9 Sheets-Sheet 9 United States Patent 3,136,237 PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS William Richard Harding Moon, London, England,

assignor to Hall Harding Limited, London, England, a company of Great Britain and Northern Ireland Filed Aug. 21, 1961, Ser. No. 132,747 19 Claims. (Cl. 9577.5)

This invention relates to photographic printing and developing apparatus of the kind wherein a sheet of sensitized material is fed to a printing cylinder with a negative, exposed, developed and ejected as a print. The invention is particularly concerned with photographic printing and developing apparatus wherein the printing cylinder thereof is mounted for rotation in one direction and return.

The invention provides a photographic printing and developing apparatus comprising a printing cylinder mounted for oscillatory rotary movement about its axis, driving means for oscillating the cylinder so that it performs successively an intake stroke in one direction of rotation and a return, ejection stroke in the opposite direction of rotation, said driving means including a clutch which is dis-engaged between the completion of an intake stroke and the commencement of an ejection stroke so that the cylinder is stationary for a timed dwell period during which a photo-copying exposure can be made, and settable control means for automatically disengaging the clutch at the completion of an ejection stroke of the printing cylinder, said control means being such that they can be set to dis-engage the clutch after a pre-determined number of intake strokes have been made.

Preferably the control means comprise a step-by-step indexing mechanism actuated in response to rotation of the printing cylinder so as to be indexed forward an equal increment at each complete oscillation of the printing cylinder. Conveniently the indexing mechanism may comprise a rotary ratchet wheel associated with driving and holding pawls.

Preferably the control means further comprise means for initially setting the indexing mechanism to position in which a number of successive increments of its movement, said number corresponding to the aforesaid predetermined number of intake strokes, bring the mechanism to a datum setting whereupon the clutch is dis-engaged, as aforesaid, at the completion of an ejection stroke.

Preferably the clutch comprises a driving clutch mem ber engageable with a driven clutch member by means of a spring loaded clutch pin.

Preferably the control means further comprise means for dis-engaging the clutch-pin-withdrawing means, said dis-engaging means being automatically rendered operative when the aforesaid indexing mechanism is brought to its datum position.

One specific construction of a photo-copying machine embodying the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of the machine,

FIGURE 2 is a side view of the mechanism associated with the clutch,

FIGURE 3 is an end view of that mechanism from the left hand side of FIGURE 2,

FIGURE 4 is a view from the other side of that mechanism,

FIGURE 5 is a plan view, partly on the line 55 of FIGURE 2, of that mechanism,

FIGURE 6 is a front view of the control mechanism,

FIGURE 7 is a rear view of the control mechanism,

FIGURE 8 is a side view of the control mechanism,

ice

FIGURE 9 is a view on the line 9--9 of FIGURE 8, and

FIGURE 10 is a plan view of the control mechanism.

The machine is shown in FIGURE 1 and comprises a desk-portion 11 on which the photo-copying assembly 12 is mounted. The photo-copying paper is placed by an operator on the surface 13 and the master copy is placed on a transparent carrier passing over a table-arm 14. One end of the carrier is wound on a spring loaded roller at the free end of the table-arm 14 and the other end is anchored to the printing cylinder of the machine. An opaque backing strip is similarly anchored at one end to the printing cylinder and has its other end wound on a second spring loaded roller. During the intake stroke of the reciprocating movement of the printing cylinder, the carrier and backing strip are drawn off their rollers and wrapped around the printing cylinder and during the ejection stroke the carrier and backing strip are drawn oif the cylinder back onto their respective rollers. On the printing cylinder, the master copy is held between the transparent carrier and the cylinder and the photo-copying paper is held between the backing strip and the carrier. A powerful lamp (e.g. a mercury vapour lamp) is disposed in the cylinder and an exposure is made between the completion of the intake stroke and the commencement of the ejection stroke. During the ejection stroke the exposed photo-copying paper is peeled off the carrier by a stripper extending across the machine and carried by a multiplicity of fingers spaced across the machine. The fingers have curved edges which can be brought against the surface of the carrier and have leading tips to pass between the paper and the carrier. The exposed sheets are guided backwards of the machine between conventional developing rollers employing the so-called semi-dry developing process. The developed sheets pass upwardly on exit from the developing rollers and emerge from the machine onto a display table 15. Air is circulated through the copying assembly by a fan 16 so that the prints are sufficiently dry to be handled on emergence from the machine.

In this example, overlapping marginal ends of the carrier and backing strip are clamped to the printing cylinder with a small spacing strip disposed between the overlapping marginal ends to space the backing strip away from the carrier. This spacing strip facilitates reception of the photo-copying sheet between the backing strip and the carrier. Entry of the photo-copy sheet is further facilitated by a driven intake roller, the periphery of which passes upwardly to the surface 13. The driven intake roller is overlaid by an idler intake roller mounted on a pivoted arm for movement to and from a position in which it holds the photo-copying sheet against the driven intake roller. Similarly, the removal of the photo-copying sheet is facilitated by a driven removal roller against which the sheet is pressed by a pivoted idler removal roller.

The loaded backing strip roller is driven by a chaindrive 32 from a sprocket 33 mounted on a shaft 34. The printing cylinder is therefore oscillated through the backing strip. The shaft 34 is journalled in bearings in flanged side plates 35. The plates 35 are secured together and to a rigid carrier plate 36 by bolts 37 and spacers 38. The shaft 34 carries a pinion 41 which engages With a rack 42 formed at one end of a connecting rod 43. The rack and pinion are contained in a pinion housing 44.

The connecting rod 43 is driven through a clutch 45 mounted on a shaft 46 similarly journalled between the plates 35. The shaft 46 carries freely a driven sprocket 47 forming one part of the clutch 45 and a crank 48 of cylindrical disc form. The crank 48 abuts against the sprocket 47, is keyed to the shaft 46 and forms the second part of the clutch 45. The crank 48 carries a crank pin 49 to which the end of the connecting rod 43 is pivotally secured. The drive to the sprocket 47 may be effected in any suitable manner. In this example, the drive includes a pulley 51 rotatably mounted on the shaft 34 and belt-driven from an electric motor housed in the desk portion of the machine. The pulley 51 is fast with a sprocket 52 from which the sprocket 47 is driven by a chain 53. The chain 53 is tensioned by a jockey wheel 54.

The driven sprocket 47 and the crank 48 are clutched together by means of a clutch pin 55 loaded by a spring 56. The clutch pin 55 is mounted in a recess 57 in the crank 48 near the periphery thereof and parallel to the shaft 46. The leading end 58 of the clutch pin 55 is shaped to provide a cam nose for engaging any one of a circumferentially arranged series of apertures 59 through the sprocket 47. The apertures 59 are aligned with grooves formed in the boss 61 of the sprocket 47.

Dis-engagement of the clutch pin 55 is effected by upper and

lower knives

65, 66. Both

knives

65, 66 are pivoted to the plate 36 and normally ride in a single peripheral groove 67 formed in the crank 48. The leading edge 68 of each

knife

65, 66 is chamfered as is indicated in FIGURE 5. The clutch pin 55 is provided with a transverse slot 69 and, when the pin 55 is engaged with the sprocket 47, a small portion of the slot 69 projects into the groove 67. As the crank 48 rotates the leading edges 68 of the

knives

65, 66 can enter the portion of the slot 69 within the groove 67 and the clutch pin 55 is therefore drawn back out of engagement with the sprocket 47.

The upper knife 65 is biased about its pivot 71 by a spring 72 into the groove 67 but can be withdrawn from the groove by means of a Bowden cable 73. The lower knife 66 carries a triangular plate 74 having a cam roller 75 at its upper apex and is biassed by a spring 76 anchored to a triangular plate 77 pivoted at 78. The plate 77 is pivotally secured to the plunger 79 of a solenoid 81. In the position shown in the drawings, the anchor pin 76a of the spring 76 seats in a cut-away corner of the plate 77 and prevents downward movement of the plate 74.

The cam roller 75 is engaged by a cam lobe 83 on the crank 48 at each revolution of the crank, and, through the plates 74 and knife 66, actuates a micro-switch 84. The micro-switch 84 is connected in the circuit of the solenoid 81 and that circuit can only be completed after the switch 84 has been actuated by the cam lobe 83. The solenoid circuit is completed and the solenoid energised under the control of a timing mechanism 85 (FIGURE 1). In this example, the timing mechanism 85 is electrical and intervals up to 60 seconds can be timed. The timing mechanism 85 can be manually set for an interval, say 20 seconds. Operation of the timing mechanism 85 initiated by a microswitch 87 (FIGURE 3) actuated by a cam 88 secured to the shaft 46. In this example, the cam 8 and the microswitch 87 are arranged so that the time interval commences at substantially the same time as the crank pin 55 is withdrawn by the knife 66.

The shaft 46 carries three

further cams

89a, 89b and 890 which operate cam follower levers 90a, 90b and 900. These levers are operatively connected to the stripper assembly, the idler intake roller and the removal roller and are arranged to cause the assembly to pivot and the rollers to co-operate with the power intake and removal rollers, in the correct sequence.

The control mechanism 91 of the machine is shown in FIGURES 6 to 10. The mechanism 91 comprises a setting ratchet wheel 92 and an operating or counting ratchet wheel 93 mounted on a shaft 94. The shaft 94 is journalled in bearings on mounting

plates

95, 95a. The counting ratchet 93 is fast on the shaft 94 and the setting ratchet 92 is rotatable on that shaft. The setting ratchet 92 carries a boss which extends through the plate 95 and carries a finger dial 96. The boss is encircled by a band spring which returns the setting ratchet 92 to a limit position. The shaft 94 carries a radial disc 97 having an indicator line 97a and which is movable over the dial 96. A gravity-operating holding pawl 98 normally engages the setting ratchet wheel 92 and holds it in its limit or set position. The counting ratchet 93 is normally engaged by both a similar holding pawl 101 and a driving pawl 102.

The two

ratchet wheels

92, 93 carry

co-acting pins

106, 107. When the dial 96 is being rotated to select the number of repetitions required, the pin 106 engages the pin 107 and the ratchet 93 is thereby rotated the appropriate amount. The counting ratchet 92 is thereafter driven by the driving pawl 102.

The driving pawl 102 is pivoted to one arm of a double arm lever 103 which is biassed by a spring 104. One end of a Bowden cable 105 is anchored to the other arm of the lever 103 and the other end of the cable 105 is anchored to an end of a lever 106 (FIGURE 2) pivoted to the plate 36. The lever 106 carries a cam roller 107 which is engaged by the cam lobe 83 once in each revolution of the crank 48. Consequently, at each revolution of the crank, the Bowden cable 105 rocks the lever 103 and indexes the counting ratchet 93 one step.

Two

similar cam plates

111, 112 are mounted on the shaft 94 at the side of the

ratchets

92, 93. The cam plate 111 has a gap 113 and an opposed small, radial slot 114 and the cam plate 112 has gaps 1150, 11517 and a slot 116. The slot 114 engages with a pin 117 carried by an arm 118 secured to a shaft 121 and the slot 116 engages a pin 122 carried by an arm 123 of a double arm lever 119 rotatably mounted on the shaft 121. The arm 118 carries a second pin 120 which can engage the arm 123 of the lever 119. The shaft 121 passes through the plate 95 and carries a release lever 124. The arm 123 is disposed in the path of the pin 107 on the counting ratchet 93 and is engaged and rotated by the pin 107 on completion of the required number of copies.

A yoke assembly 125 is pivoted between two small cheek plates 126 fixed to the plate 95. The end of the Bowden cable 73 is connected to the yoke assembly 125 and consequently that assembly is biassed to the position shown in FIGURE 8 by the spring 72. The yoke assembly 125 carries a push-button stem 127 which passes through the plate 95. By pressing the push-button 127 the yoke assembly 125 is moved backwardly from the position shown in FIGURE 8. The other arm 128 of the double arm lever 119 then swings in front of the upper part of the yoke assembly 125 under the spring 130 and prevents its return.

The operation of the machine to produce a multiplicity of copies will now be described, assuming that initially the clutch pin 55 is engaged by the upper knife 65. The switches 131, 132 are operated to switch on the exposure lamps and the driving motor.

The operator places the master copy on the transparent carirer and a sheet of photo-copying paper on the surface 13. He then dials the required number of copies on the dial 96 and presses the push-button 127. Pressing the push-button 127 rotates the yoke assembly 125, and, through the Bowden cable 73, dis-engages the upper knife 65 from the slot 69 in the clutch pin 55. Simultaneously the arm 128 of the lever 119 swings in front of the yoke assembly 125 and acts to hold the upper knife 65 in its raised position.

When the upper knife 65 is raised, the clutch pin 55 engages under the spring 56 in the aligned aperture 59 in the sprocket 47 and the crank 48 is driven. Motion is therefore imparted to the connecting rod 43, the shaft 34 driven, and the printing cylinder rotated to take in the master copy and the photo-copying sheet.

The drive to the printing cylinder is such that it is rotated through about 280 degrees. The idler intake roller is brought into co-operation with the continuously driven power intake roller by rotation of the cam 90b.

As the crank 48 rotates, the cam lobe 83 thereon engages the cam roller 107 on the lever 106 and causes that lever to pivot. This motion is transmitted through the Bowden cable 105 to the double arm lever 103. The driving pawl 102 therefore effects a driving stroke and the counting ratchet 92 is indexed one step forward.

The crank 48 continues to rotate until the lower knife 66 engages the slot 69 in the clutch pin 55 and withdraws that pin from the sprocket 47. Just before the pin 55 is disengaged from the sprocket 47 the cam 88 on the shaft 46 actuates the micro-switch 87 and energises the timing mechanism 85. Also just before the pin 55 is dis-engaged from the sprocket 47, the cam lobe 83 on the crank 48 engages the roller 75 and pivots the triangular plate 74 and the lower knife blade 66, and completes the circuit to the solenoid so that the solenoid can be energised at the completion of the timed interval.

At the completion of the timed interval, the solenoid 81 is energised through contacts operated by the timing mechanism 85 and the closed contacts of the micro-switch 84. When the solenoid 81 is energised, the plunger 79 is drawn downwardly to pivot the triangular plate 77 and dis-engage the plate 77 from the pin 76a. The lower knife 66 is then dis-engaged from the clutch pin 55 by the spring 76 and re-engages the sprocket 47. The crank 48 is therefore again driven. Simultaneously the contacts of the micro-switch 84 are opened, interrupting the solenoid circuit. That circuit remains interrupted until the roller 75 is again engaged by the cam lobe 83. The solenoid S1 is therefore de-energised during the exposure period.

If the upper knife 65 is still raised, the crank 48 will continue to rotate until the clutch pin 55 is again engaged by the lower knife 66. The cycle is then repeated. Each revolution of the crank 48 enables one photo-copy of the master copy to be made. The operator places a sheet of photo-copying paper on the surface 13 immediately after the previous sheet has been taken into the machine, the consecutive sheet being drawn onto the printing cylinder at the appropriate time.

Consider now that only one more photo-copy has to be made to complete the number of copies for which the dial was set. During the revolution of the crank 48 to produce this copy, the cam lobe 83 will engage the roller 107 and index the counting ratchet one step forward through the Bowden cable 105. Due to the initial setting of the counting ratchet 92, the pin 107 on that ratchet will engage the arm 123 of the double arm lever 119 during the step. The lever 119 is therefore caused to pivot and the arm 128 dis-engaged from the yoke assembly 125. That assembly therefore rotates back under the action of spring 130 and the tension on the Bowden cable '73, is removed. The leading end of the upper knife 65 therefore drops down to a position in which it will engage the clutch pin slot 69 during the revolution of the crank 43. When the clutch pin 55 is withdrawn from the sprocket 47 it remains withdrawn until the push-button stem 127 is again pressed. The machine therefore automatically stops when the required number of copies have been made.

The pivotal movement of the lever 119 caused by engagement of the arm 123 by the pin 107 causes, through the arm 123 and the pin 122, rotation of the cam plates 112. As the cam plate 112 rotates the holding pawl 101 associated with the counting ratchet 93 rides-up out of the gap 1151) onto the periphery of the cam 112. The counting ratchet 93 therefore returns under the action of spring 131 to the position in which its pin 107 abuts against the pin 106 of the setting ratchet 92. The counting ratchet therefore returns to its initial set position and the same number of copies of a second master copy or negative can be made without resetting the dial 96. It is only necessary to press the button 127.

If it is desired to make a different number of copies of a second master copy, say a smaller number of copies,

this can be done by moving the dial through the necessary further steps. However, where a greater number of copies is required, the control mechanism must be reset and the release lever 124 is provided for this purpose.

When the end of the release lever 124 is raised the shaft 121 is pivoted. The arm 118 is therefore rotated and, through the pin 120, the arm 123 of the double arm lever 119 is also rotated. The movement of these arms causes, through the pins 117, 122, rotation of the

cam plates

111, 112. The rotation of the

cam plates

111, 112 caused by movement of the release lever, causes both the holding

pawls

98, 101 to ride-up out of their gaps onto the peripheries of the

cam plates

111, 112. Both the

ratchet wheels

92, 93 therefore rotate under the action of

springs

100, 131 back to their zero positions. The required number of copies can then be dialed.

The foregoing machine has the substantial advantage that a multiplicity of photo-copies of a master copy or negative can be produced without the necessity for the operator to handle the master copy or negative between successive prints. This considerably reduces the risk of mutilation of the master copy or negative. Further, a selected number of copies can be produced without the necessity for the operator to maintain a count of the copies. Also the exposure time is automatically controlled once the operator has set the timing mechanism.

The invention is not restricted to the details of the foregoing example. For instance, sensitized material may be fed automatically into the machine, for example from a stack of such paper or from a stock roll.

I claim:

1. Photographic printing and developing apparatus comprising a printing cylinder mounted for oscillatory rotary movement about its axis, driving means for oscillating the cylinder so that it performs successively an intake stroke in one direction of rotation and a return, ejection stroke in the opposite direction of rotation, said driving means including a clutch comprising a driving clutch member, a driven clutch member and a clutch pin carried by one of the clutch members and movable into and out of coupling engagement with the other clutch member whereby to respectively effect engagement and dis-engagement between the clutch members, said clutch members being disengaged from each other between completion of an in take stroke and commencement of an ejection stroke so that the cylinder is stationary for a time dwell period during which a photo-copying exposure can be made, and settable control means for automatically moving the clutch pin in a direction to effect dis-engagement between the clutch members at the completion of an ejection stroke of the cylinder, said control means being so constructed and arranged that it can be set to dis-engage the clutch members upon completion of a pre-determined number of intake strokes of the cylinder.

2. Apparatus as claimed in claim 1, in which the clutch pin is spring loaded and reciprocable in a bore in one of the clutch members.

3. Apparatus as claimed in claim 1, in which the clutch pin is reciprocable in a bore in the driven clutch member, the apparatus also including spring means normally and yieldingly moving the clutch pin in a direction to effect engagement between the clutch members, said control means comprising clutch pin withdrawing means for moving the clutch pin in a reverse direction against the action of the spring means to effect dis-engagement between the clutch members.

4. Apparatus as claimed in claim 1, in which the control means comprises a step-by-step indexing mechanism actuated in response to rotation of the printing cylinder so as to be indexed forward an equal increment at each complete oscillation of the printing cylinder, said indexing mechanism comprising a rotary ratchet wheel, a driving pawl and a holding pawl engageable with the ratchet wheel, a pivoted lever carrying the driving pawl and rockable once at each complete oscillation of the printing cylinder to efi'ect a ratchet-driving stroke of the driving pawl, and means for initially setting the indexing mechanism to a position in which a number of successive increments of its movement, said number corresponding to the aforesaid pre-determined number of intake strokes, brings the mechanism to a datum setting whereupon the clutch is dis-engaged, as aforesaid, at the completion of an ejection stroke.

5. Apparatus as claimed in claim 4, in which the setting means comprises a manually settable member associated with the indexing mechanism and provided with indices indicative of the number of increments of movement of the indexing mechanism to bring that mechanism to its datum setting.

6. Apparatus as claimed in claim 5, in which the member comprises a finger dial.

7. Apparatus as claimed in claim 4, in which the settable member is secured to a second ratchet wheel disposed adjacent the first said ratchet wheel, said two ratchet wheels having co-operating parts such that when the second ratchet wheel is rotated in one direction, the parts co-operate to cause rotation of the second ratchet wheel but when the first ratchet wheel rotates in the same direction the parts do not co operate and the second ratchet wheel is not rotated.

8. Apparatus as claimed in claim 7, in which said cooperating parts comprise opposed projections projecting axially from the two ratchet wheels.

9. Apparatus as claimed in claim 3, in which the clutch pin withdrawing means comprises a pivotally mountedelement biased to engage with the clutch pin during rotation of the driven clutch member, the element and pin having co-operating inclined surfaces such that as the element engages the pin, the pin is withdrawn from the driving clutch member.

10. Apparatus as claimed in claim 9, in which the element comprises a tapered leading end, the inclined surface of which provides one of the said co-operating surfaces, and in which the co-operating surface on the pin is provided with a Wall of a transverse slot formed therein.

11. Apparatus as claimed in claim 10, in which the leading end of the element slides in a slot extending peripherally around the driven clutch member and intersecting the clutch pin bore.

12. Apparatus as claimed in claim 11, in which the control means further comprises means for dis-engaging the clutch-pin-withdrawing means.

13. Apparatus as claimed in claim 12, in which said disengaging means comprises a manually movable member connected to the pivoted element so that movement of the member causes the element to pivot against its bias out of engagement with the clutch pin.

14. Apparatus as claimed in claim 9, in which the clutch is dis-engaged during a dwell period by a second pivotally mounted element biased to engage with the clutch pin during rotation of the driven clutch member and having a tapered leading end sliding in the peripheral groove around the driven clutch member.

15. Apparatus as claimed in claim 14, in which the said second element is dis-engaged from the clutch pin by means comprising a solenoid which is energised through contacts actuated from a timing mechanism.

16. Apparatus as claimed in claim 15, in which operation of the timing mechanism is initiated in dependence on movement of the driven clutch member.

17. Apparatus as claimed in claim 16, in which said timing mechanism also times the dwell period of the printing cylinder.

18. Apparatus as claimed in claim 1, in which the driving means also comprises a pinion drivingly connected to the printing cylinder and meshing with a rack formed at one end of a connecting rod coupled at its other end to a crank driven through the clutch.

19. Apparatus as claimed in claim 18, in which the crank is provided by the driven member of the clutch.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. PHOTOGRAPHIC PRINTING AND DEVELOPING APPARATUS COMPRISING A PRINTING CYLINDER MOUNTED FOR OSCILLATORY ROTARY MOVEMENT ABOUT ITS AXIS, DRIVING MEANS FOR OSCILLATING THE CYLINDER SO THAT IT PERFORMS SUCCESSIVELY AN INTAKE STROKE IN ONE DIRECTION OF ROTATION AND A RETURN, EJECTION STROKE IN THE OPPOSITE DIRECTION OF ROTATION, SAID DRIVING MEANS INCLUDING A CLUTCH COMPRISING A DRIVING CLUTCH MEMBER, A DRIVEN CLUTCH MEMBER AND A CLUTCH PIN CARRIED BY ONE OF THE CLUTCH MEMBERS AND MOVABLE INTO AND OUT OF COUPLING ENGAGEMENT WITH THE OTHER CLUTCH MEMBER WHEREBY TO RESPECTIVELY EFFECT ENGAGEMENT AND DIS-ENGAGEMENT BETWEEN THE CLUTCH MEMBERS, SAID CLUTCH MEMBERS BEING DISENGAGED FROM EACH OTHER BETWEEN COMPLETION OF AN INTAKE STROKE AND COMMENCEMENT OF AN EJECTION STROKE SO THAT THE CYLINDER IS STATIONARY FOR A TIME DWELL PERIOD