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Publication numberUS3266406 A
Publication typeGrant
Publication dateAug 16, 1966
Filing dateSep 23, 1963
Priority dateFeb 11, 1963
Publication numberUS 3266406 A, US 3266406A, US-A-3266406, US3266406 A, US3266406A
InventorsFrans Stievenart Emiel
Original AssigneeGevaert Photo Prod Nv
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Photographic copying apparatus stripping mechanism and method
US 3266406 A
Images(2)
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Description  (OCR text may contain errors)

Aug. 16, 1966 E. F. STIEVENART 3,266,406

PHOTOGRAPHIC COPYING APPARATUS STRIPPING MECHANISM AND METHOD Filed Sept. 25, 1965 2 Sheets-Sheet 1 INVENTOR. 3%Z6Z 17555227221272 A 16, 1966 E F. STIEVENART 3,266,406

PHOTOGRAPHIC COPYING APPARATUS STRIPBING MECHANISM AND METHOD Filed Sept. 23, 1963 2 Sheets-Sheet 2- United States Patent 3,266,406 PHOTOGRAPHIC COPYING APPARATUS STRIP- PING MECHANISM AND METHOD Emiel Frans Stievenart, Kiel-Antwerp, Belgium, assignor to Gevaert Photo-Producten N.V., Mortsel-Antwerp, Belgium, a Belgian company Filed Sept. 23, 1963, Ser. No. 310,826 Claims priority, application Netherlands, Feb. 11, 1963, 288,817 13 Claims. (Cl. 9589) The invention relates generally to document copying devices and more specifically to an improved copy sheet stripping mechanism for a photographic copying device of the image-transfer type.

Photographic copying devices in which an exposed light-sensitive sheet is urged in the presence of processing liquid into intimate contact with an image-receiving sheet are well known in the art. Very little attention, however, has been given to the problem of separating by means of mechanical instrumentalities the damp, tightly adhering sheets from each other.

One device which deals with this problem is disclosed in Belgian patent specification 604,557 of General Aniline and Film Corporation in New York to which corresponds Canadian patent specification 656,554. In this device, use is made of an image-receiving material and a lightsensitive material in the form of Webs which are continuously supplied from corresponding supply rolls. This arrangement avoids the problem of sheet separation, since the leading edges of both webs are caused to follow separate paths when the device is loaded, which paths diverge after a sufficient time of contact between the sheets has occurred. The disadvantages of such device, however, are a considerable waste of material, viz, the part of the web between successive copies, plus the impossibility of producing multiple copies with a single exposed light-sensitive material.

A second device in which sheet separation is performed is disclosed in United States Patents 3,020,837 and 3,062,135 of C. R. Taylor et al. In this device, the receiving material is applied under pressure to the processed light-sensitive material with its leading edge extending over a separating knife at a point which occurs immediately before the separating knife, and therefore only a very brief time is possible for the diffusion process to take place. Moreover, complicated means have to be provided to permit displacement of the separate knife and a consequential extension of the time for the diffusion, in case a plurality of copies are to be produced.

The object of the invention is to provide a copying apparatus in which the noted disadvantages are overcome.

Another object of the invention it to provide a stripping mechanism which can be mounted at the outlet of existing commonly used photographic copying apparatus of the image-transfer type, and is adapted to perform automatically the step of separating from each other the sheets leaving the apparatus.

Still another object of the invention is to provide a stripping mechanism for a copying apparatus that is of simple design and construction, and reliable in operation.

An advantage of an apparatus according to the present invention is that the device is suited for the separation of a light-sensitive material and an image-receiving material not only when both are wetted by the processing liquid prior to being pressed against each other, but when just the light-sensitive material is wetted by the processing liquid, and even when the processing liquid necessary for performing the diffusion transfer is only present between the contacting faces of both materials.

Both latter methods, wherein as a result of the small quantity of processing liquid both materials or sheets Patented August 16, 1966 adhere strongly to each other, have the important advantage that the produced copies are dry or almost dry after the separation.

The device according to the present invention is particularly suited for producing copies according to the known silver halide diffusion transfer process.

According to this process a light-sensitive material comprising a silver halide emulsion layer is image-wise exposed to an original and pressed against an image-receiving material in the presence of processing liquid, a developing agent and a silver halide complexing agent, whereby the unexposed and undeveloped parts of the silver halide are complexated, and diffuse to the image-receiving material, where they are converted into a silver image by the action of developing nuclei. The basic disclosure of the diffusion transfer process appears in United States Patent 2,352,014 to Rott and numerous improvements have now appeared in the patented art, to which reference may be had if desired for the details involved in the practice of this process. While certain particular materials have been found especially well adapted for use in the apparatus of this invention, as will be hereinafter explained it has general application in the field of dilfusion transfer and is not limited to these or any other specific materials.

The invention will be further explained by the following examples and illustrated by the accompanying drawings, in which:

FIGURE 1 is a diagrammatic side view of a copying apparatus embodying the principles of this invention;

FIGURE 2 is a diagrammatic top view of the copying appartus of FIG. 1, the cylinder being shown in a different position than that seen in FIG. 1, certain parts being omitted for sake of clarity;

FIGURE 3 is a diagrammatic side view of a copying apparatus associated with a modified form of separating device according to this invention;

FIGURE .4 is an enlarged view illustrating the relative positions of the leading edges of the sheets in the modified separating device of FIG. 3;

FIGURE 5 is a diagrammatic side elevation of another form of separating device for association with existing copying device, the parts thereof being seen in inoperative position; and

FIGURE 6 is a view of the device of FIG. 5 with the parts in operative position.

A cylinder or drum 10 is supported on a shaft 11 for rotation about a generally horizontal axis. The cylinder is equipped with means 22 extending transversely across its width at a point on the periphery for gripping and holding the leading edge of a sheet within a slit 21. A variety of arrangements capable of serving as the gripping means 22 are known in the printing art including an array of spaced pivotable fingers carried along with the cylinder, either recessed or not, which fingers can be elevated for the introduction of the sheet edge and then depressed to engage the same, as well as a spring-biased clamping blade or a wedge-actuated clamping block usually situated within a traverse slot or recess. As the details of the particular gripping means forms no essential part of this invention, it has been illustrated only diagrammatically.

At the bottom of the cylinder is a tank 12 for containing a supply of processing fluid 13 of the type conventionally used in diffusion transfer processes. The level of fluid supply 13 is preferably maintained below the surface of the cylinder and an applicator roller 14 is arranged partially immersed in fluid 13 with an opposite portion of its periphery closely contiguous to the cylinder surface, the roller being positively driven by means not shown at the same peripheral speed as cylinder 10. Roller 14 picks up a film of the fluid, and applies it against the face of the sheet carried on the cylinder surface. Other ways of coating a thin film of processing fluid upon the sheet face can, of course, be substituted and, if desired, roller 14 or its equivalent can be so mounted as to allow displacement away from the regions of the cylinder surface not bearing a sheet. Surplus fluid can be removed by a pressure or squeegee roller 15 situated beyond the applicator roller 14 but within the confines of tank 12 to recover the surplus.

Placement of the light-sensitive sheet 26 on the cylinder is facilitated by means of a feed plate or guide 18 upon which the sheet can be laid and/or advanced to insert the leading edge thereof into the gripping means 22 of the cylinder. Guide 18 is situated in advance of the tank at a locus on the cylinder periphery which can be varied considerably up to the point of sheet separation to best suit spatial and design considerations. The light-sensitive sheet can be exposed preparatory to placement upon the cylinder surface, e.g. by means of a known pneumatic pressure printer in which a pressure system ensures a close contact between the original and the light-sensitive "sheet during the illumination, a rotating tubular light source around which by means of driven belts the original to be duplicated is passed while in contact with the light- 'sensitive sheet, etc.

Further along the cylinder periphery beyond squeegee roller 15 is the image-receiving sheet feeding station formed by the pressure roller 16 riding'on the surface of the cylinder and a sheet guiding passageway defined by guides 19 and 20. These guides are curved at the end adjacent the cylinder surface to advance the image-receiving sheet directly to the nip of roller 16.

To facilitate access to the leading edge of image-receiving sheet 27 for easy ultimate separation of that sheet from sheet 26, the cylinder surface is provided at a point just preceding the gripping means with an upwardly and rearwardly inclined projection or cam 23 terminating at its rear end as closely as possible to the leading edge of the gripped sheet 26. Projection 23 can extend the full width of the cylinder or over just a portion thereof, in which event it is preferably situated approximately midway of the cylinder width. The radial extent of the projection at its maximum height adjacent gripping means 22 need not be especially great, provided it is sufiicient to raise a knife 17, to be described later, clear of the leading edge of sheet 26. In the event the particular gripping means effectively shields the edge of sheet 26, as in the case of a clamping blade overlapping the sheet edge and lying fiat or almost so on the cylinder surface, a smoothly curved center recess could be substituted for projection 23 to direct the knife beneath the edge of the top sheet and then up onto the blade. As a further alternative, one or more elements of the gripping system, e.g. spaced gripping fingers or a transverse clamping block, can be so configured as to serve the purpose of projection 23.

Further along the cylinder periphery from pressure roller 16 is the sheet separating knife 17 mounted to pivot about pins 24 and lightly biased by spring means (not shown) e.g. a torsion spring, against the cylinder surface. Alternatively, the knife blade can be naturally resilient to permit movement of its free end. Knife 17 extends across the entirety of the cylinder surface but, at least where projection 23 is localized in a central region of that surface, the blade is adavantageously symmetrically tapered from a rounded end, i.e. more or less cusp-shaped, to penetrate more smoothly beneath the leading edge of sheet 27 and thence between the sheets throughout their contacting area. One configuration very satisfactorily generally corresponds coincidentaly to the curvature of known probability curves.

It is necessary to the proper separation of the sheets according to the present invention that the sheet 27 be applied to the cylinder surface in such a manner that its leading edge slightly precedes, say by one-half inch or so, the corresponding edge of sheet 26.

A crude mechanical delivering control for performing this step has been indicated diagrammatically in FIG. 1. It includes the roller 60 which is resting on top of a stack 63 of sheets 27. The roller 60 is mounted for free vertical movement, and is coupled by means of a flexible shaft and a magnetic clutch to a continuously turning electric motor (not shown in the figures). When the roller 60 is turning, its peripheral speed is equal to that of the cylinder 10. The magnetic clutch is controlled by the micro-switch 61, mounted beside the cylinder 10, and is controlled in its turn by a cam 62 rotating with cylinder 10 and so configured as first to close microswitch 61 when the projection 23 takes about its lowest position so as to let the roller 60 start turning for advancing the uppermost sheet 27 of the stack 63 along a path between the guides 19 and 20 which is slightly shorter than the distance on the periphery of cylinder 10 between the projection 23 in the said lowest position and the position as represented in FIG. 1, whereby the sheet 27 arrives slightly leading before the sheet 26 at the cylinder periphery, and second, after the sheet 27 has been applied at least with its leading part against the projection 23 and the leading part of the wetted sheet 26 on the cylinder so as to adhere thereto, to open the micro-switch for permitting the sheet 27 to be withdrawn free from under the roller 60 upon further turning of cylinder 10.

In the preceding description, all terms of orientation or operational relationship are with respect to the direction of cylinder rotation.

The pressure rollers 15 and 16 are mounted for free rotation on their corresponding shafts. The surface of said pressure rollers is desirably covered with a resilient materials. Unless the latter material yields sufficiently to accommodate the passage of cam 23, the bearings supporting these rollers along with roller 14 should be yieldably mounted.

Cylinder 10 is made from a hard poly(vinyl chloride). It is clear that also other materials which are resistant to the processing liquid may be used for the construction of the cylinder, e.g. stainless steel.

Roller 14, which with its lower part dips into the processing liquid 15 has no direct contact with the periphery of the cylinder 10 except through the sheet 26. Separating knife 17 can be conveniently made out of a blade of stainless steel. As already indicated, the separating knife covers the total width of the cylinder and rests with its front edge on the cylinder surface. At least the free end portion of knife 11 preferably extends substantially tangentially to the cylinder periphery.

The above described embodiment of the apparatus is operated as follows:

An image-Wise exposed light-sensitive sheet 26 consisting of a paper support bearing a light-sensitive silver halide emulsion layer, is guided with its emulsion side turned downwardly over the guide member 18 until its leading edge enters the slit 21 of the gripping system, which at that moment is situated in alignment with the guide element 18. The gripping system 22 is closed and the cylinder 10 is started to rotate. Rotation of the cylinder causes the-light-sensitive sheet 26 to wrap around the periphery of the cylinder with the emulsion side thereof facing outwardly.

When the leading edge of the light-sensitive sheet arrives at the roller 14, the film of processing liquid on the surface of the roller 14 contacts the emulsion side of the sheet 26, and a meniscus forms between the said sheet and the roller 14. Consequently, the light-sensitive emulsion is wetted with the processing liquid which contains as is well known in the art a developing substance, a complexing agent for the silver halide and an alkaline substance, and the development of the exposed silver halide superfluous liquid is pressed away from the light-sensitive sheet 26 by the pressure roller 15.

A few moments later the cylinder reaches the position idicated in FIGURE 1 with cam 23 just before passing beneath roller 16.

The image-receiving sheet 27 under the guidance of the guide members 19 and 20, is moved forwardly by hand or by suitable means (not shown) until its leading edge contacts and rests on the inclined surface of the cam 23 on the cylinder with the extreme edge entering the nip of roller 16. Thus, the image-receiving sheet 27 is slightly leadingthe light-sensitive material 26.

By means of the pressure roller 16, the image-receiving sheet is firmly pressed against the wetted light-sensitive sheet. The complexing agent present in the processing liquid causes the non-exposed and consequently non-developed silver halide to diffuse as a soluble complex from the light-sensitive emulsion layer into the image-receiving layer, Where it is converted into a legible silver image, all as is conventional in tthe diffusion transfer process.

When the cylinder 10 moves to the position illustrated in FIGURE 2, then the separation of the image-receiving sheet 27 from the light-sensitive sheet 26 is started. The separating knife 17 is lifted up by the slanting cam 23 and arrives with the protruding part of its edge 25 under the image-receiving sheet 27. The lifting of the separating knife 17 from its original position by the cam 23, causes temporarily a stronger urging of the front portion of the knife 1'7 against the surface bearing the leading edge of the image-receiving sheet 27, i.e., the sloping cam 23. Thereby it is prevented that the'leading edge of the sheet 27 passes beneath the knife without being separated.

As the cylinder continues to rotate, the separating knife gradually penetrates between the sheets 26 and 27 over the full width thereof.

The cam 23 prevents the front edge of the separating knife from impacting against the light-sensitive sheet 26 at the line where the latter is folded and is maintained in the slit 21. Thereby it is avoided that the front edge of the separating knife would cut into the light-sensitive sheet and tear it from the cylinder 10, or would gouge into the emulsion layer of the light-sensitive sheet during the further rotation of the cylinder.

The image-receiving sheet 27 is delivered above the separating knife 17 whereas the light-sensitive sheet 26 remains on the periphery of the cylinder 10.

Owing to the small quantity of processing liquid which is present during the diffusion transfer step, the imagereceiving sheet 27 is almost dry after the separation and, is in condition for immediate use even without any drying after-treatment.

It has been found that excellent results can be obtained with the above-described apparatus when a light-sensitive sheet and a receiving sheet are used, provided that the tendency of the sheets to adhere to each other is not too strong. This tendency can be controlled by selection of the compositions of the contacting layers thereof.

In the latter respect, sheets wherein the binding agents of the top layer of the light-sensitive sheet essentially differ from the binding agents of the top layer of the receiving sheet are particularly advantageous.

Materials which are especially suited for use in apparatus according to the present invention are disclosed in the US. patent application 187,437, now abandoned, describing a process for the production of images according to the silver complex diffusion transfer process, comprising the use of a light-sensitive sheet, consisting of a support carrying a silver halide emulsion layer on top of which is applied an after-layer of a gelatin-free water-permeable colloid, and a receiving sheet selected from the group consisting of paper, film and textile materials; and in the U.S. patent application 300,099 describing a like process comprising the use of a light-sensitive sheet bearing a silver halide emulsion layer and a water-permeable external layer, and an image-receiving sheet comprising a support and an uppermost layer containing a binding agent and a filler.

It is possible to further reduce the time required for producing a copy by raising the temperature of the processing liquid, as for example, by providing an electrical heating element under the tank 12 which is thermostatically controlled, and/or by heating the sheets pressed against each other by means of heated rollers or a hot air blast.

After the removal of the image-receiving sheet 27, the light-sensitive sheet 26 remains on cylinder 10 until positively stripped off after, of course, unlocking the gripping system 22. If one wishes to makemore copies, the lightsensitive sheet 26 is left in place and the above described treatment is repeated each time with a new image-receiving sheet. By having the light-sensitive material remain in place, the operations required for the production of each new copy are very much simplified.

The described embodiment is not limitative of the scope of the invention. The cam 23, as well as the separating knife 17 and more particularly its front edge 25, may have other shapes than represented in the figures. The cam 23 may be replaced by a projection extending over the full width of the cylinder 10 and having a slightly inclined upper surface, as already suggested.

Moreover, the cam 23 may also accomplish the function of the gripping mechanism 22. To this end the cam 23 may be constituted by a curved metal clip (not shown) lying close to the periphery of the cylinder 10, and being resiliently mounted so as to enable its edge to be lifted a few millimeters for insertion of the leading edge of the light-sensitive sheet 26 there beneath. Upon releasing the clip and as the cylinder 10 rotates through its cycle, the said clip holds the leading edge of sheet 26, as well as lifts the separating knife 17 while passing beneath it.

The cylinder may be replaced by a cylinder segment of a length sufficient for supporting on its periphery the sandwich of both sheets.

The device according to the present invention is particularly appropriate for being incorportaed in an automatic printing apparatus.

To suit this purpose, automatically operating means can be provided for the advancing of the image-wise exposed light-sensitive sheets 2.6 on the guide member v18 to the slit 21 of the cylinder 10, for the closing of the gripping system 22, for controlling the rotaiton cycle of the cylinder 10, and for performing the feeding of the image-receiving sheets 27 to the cam 23. Mechanisms adapted to perform this function are Well known in the printing press art and do not require specific illustration or description here. An exposure system associated with the described device as well as supply stacks for the lightsensitive sheets 26 and the image-receiving sheets 27 are prefer-ably used therewith. In that case the operation is performed as follows:

The original to be copied is introduced into the apparatus. By an appropriate sheet-feeding mechanism a light-sensitive sheet 26 is removed from its stack and, in aligned contact with the original, is passed along a light source. The original is ejected from the apparatus while the image-wise exposed sheet 26 is introduced with its lea-ding edge into the slit 2 1 of the cylinder 10 which has been rotated to the proper position and thereafter is wrapped around the cylinder. Another sheet-feeding mechanism removes at the right moment a sheet 27 from its stack and feeds it into the guiders 19 and 20 in tuned relation to the approach of sheet 26. This sheet is pressed against the sheet 26 in the above described way for a given time, and these separated again therefrom. When a number of copies of the original is required, the cycling control device of the apparatus is set in such a Way that the light-sensitive sheet 26 is not removed from the cylinder 10 after the copying cycle has finished. Hence, the cylinder 10 performs another revolution and a second copy is produced on a new sheet of copying material.

After the required number of copies has been delivered, the gripping system 22 is released and the light-sensitive sheet is removed from the cylinder by a known system, comprising for example, two rollers rotating at relatively high speed and in opposite directions, which are urged temporarily against the sheet 26 and thereby rapidly unwrap the said sheet from the periphery of the cylinder.

The application of the processing liquid may be done in other ways from the one explained in the foregoing example. It is thus possible to partially immerse the cylinder itself in the treating liquid. Further, the image-receiving sheet can also be moistened before it is pressed on to the light-sensitive sheet. In both these cases, the two materials are, however, intensively wetted so that it is not possible to produce a copy which is almost dry, unless means are furnished for drying the copy obtained after the image has been formed.

It is also possible to supply each time a measured quantity of fresh processing liquid for each copy to be produced. In that case deterioration or oxidation by air of the processing liquid is avoided.

Finally, it is also possible to omit the tank 12 containing the treating liquid. This can be done, for example, when the image-receiving sheet and/ or the light-sensitive sheet contains rupturable capsules filled with processing liquid which is spread over the contacting surfaces when pressing the light-sensitive sheet against the image-receiving sheet. The tank 12 can also be omitted when the formation of the image in the image/receiving sheet is produced by heating the sheets pressed together, the sheets containing besides the substances required for the formation of the image also compounds which, upon heating, set free water or which hydroylse whilst setting free an alkaline substance, and containing also hydrophilic softening agents.

Although the foregoing embodiment of the invention is preferred, those skilled in the art will appreciate that it requires a specially designed unit and is not very well adapted for association with existing devices of the type in question. There is shown in FIGS. 3 and 4 a modified form of separating device which does satisfy the latter need in association with a typical known contacting apparatus.

The contacting apparatus, which represents the construction of a number of known units, comprises the housing 33, the guide plates 30, the outlet pressure roller pair 31, the tank 32 holding the processing liquid and an outlet opening 34.

The separating device comprises a plurality of continuously driven rollers 35, 36 and 37 mounted between two upstanding supports 38, a tray 39 for receiving the light-sensitive sheets and a tray 40 for receiving the image-receiving sheets, both trays being supported by the members 38 on opposite sides thereof, a sloping guide plate 43, separating knife 41 vertically movable according to the dot and dash line 42. The separating device is so positioned behind the copying apparatus that the sloping support 43 adjoins the outlet 34 of the copying apparatus.

The rollers 35, 36 and 37 rotate at a peripheral speed which is equal to the peripheral speed of the roller pair 31. Roller 3'5 is constructed of metal rollers 36 and 37 contact each other and are provided with a resilient covering.

The separating knife 41 consists of a permanently curved stainless steel blade with a thickness, say, of 0.5 mm., extending the width of the roller 35. The front edge is bevelled and the configuration of the knife has the same tapered or cusp shape as the knife of the principal embodiment. The knife is supported with its extremities disposed for sliding movement along vertical rods or slots provided on supports 38. The sliding movement is performed either by hand or by automatic means, for instance, solenoids which press the knife from its inoperative position (shown in FIG. 4) down to its operative position (shown in FIG. 3) in which the front edge of the knife contacts over its full length the periphery of roller 35. The said means for moving the knife are not shown, since they are not essential for the understanding of the present embodiment. Spring means can be placed to return the knife to inoperative position or the automatic means can incorporate such means.

The operation of the apparatus is as follows: An imagewise exposed light-sensitive sheet 26 is .introduced, its emulsion side facing upwardly, together with an imagereceiving sheet 27, its image-receiving side facing downwardly, into the respective channels defined by the guide plates 30. The light-sensitive sheet follows the path 45; the image-receiving sheet follows the path 46. After passing through the processing liquid, both sheets are squeezed between the pressure roller pair 31 and leave same adhering to each other. In introducing the sheets, care is taken to insure that the lowermost sheet, i.e. sheet 26, slightly leads the other on emergence from the apparatus through the outlet 34. The roller pair 31 forces the sheets upward-1y along the sloping support 43, until the leading edge of sheet 26 takes the position as shown in FIGURE 4. At that moment the said leading edge actuates an electrical sensing device, such as a photoelectric cell or a microswitch, not shown, whereby the electrical circuit of the solenoids is closed and the knife 41 is moved downwardly.

The knife deflects the leading edge of the sheet 26 so as to cause the said edge to move, upon further advance of the sheet, in the direction indicated by the dotted lines 47 and into tray 39. The front portion of the knife in operative position extends substantially tangentially of the periphery of the roller 35 so that the leading edge of sheet 27, which naturally tends to resist deflection, will slide over the knife, and thus will be separated from the underlying sheet. The roller pair 36, 37 completes the advance of the sheets when they have left the roller pair 31. The image-receiving sheet 27 is further deflected by the metal guide fingers 48 fixed on the separating knife, so as to cause it to follow the path 49 whereby it drops after separation in the tray 40.

The operator of the modified apparatus need not wait till the sheets leave the copying apparatus for then separating them after some seconds, as is presently the case, but may continuously feed the copying apparatus without worrying about the separation of the sheets. Also the operators hands will no longer be dirtied by processing liquid when separating the sheets, since he is only occ-upied with the dry side of the apparatus.

As both sheets pass through the processing liquid, a relatively great amount of liquid is carried along which in some cases may cause the sheets in the trays 39 or 40 to adhere to each other. In such cases it may be useful therefore to provide for a hot air blast, blowing between the roller 37 and the back side of the knife 41.

The length of the sloping support 43 is selected, considering the peripheral speed of the roller pair 31, in accordance with the time that the sheets have to remain in contact with each other. For rather long times (30 secends or more) the length of the support 43 will make the distance between the roller pairs 31 and 36, 37 exceed the distance between the leading and the trailing edge of the sandwich of both sheets. Another problem which may be encountered is the buckling of the sandwich on the support 43 before the leading edge is gripped between the rollers 36, 37. In both cases, another roller pair should be provided between the said roller pairs in order to grip both sheets at a suitable intermediate point.

When the trailing edge of the sandwich of both sheets has passed beyond the electrical sensing means, the current in the solenoids is interrupted and the separating knife returns to its initial inoperative position.

Also for the alternative embodiment of the separation device, one is not limited to the illustrated construction.

. 9 Many modifications or simplifications will be evident to one skilled in the art.

The separting knife 41 may, e.g., execute a pivoting movement instead of the vertical movement, which in practice will simplify the construction. Furthermore, the roller 35 may also be free turning, or in the simplest embodiment, may be replaced by a curved supporting member.

A second alternative embodiment of the separating device along the same general lines as that of FIGURES 3 and 4 is shown in FIGURES 5 and 6. The said device is used in association with a contacting apparatus similar to that represented in FIGURE 3 except that the sheets are delivered in superposed condition'along'a horizontal part 66 of the casing.

The separating device comprises a continuously driven roller 50, a bodily movable, freely rotatable roller 51, a separating knife 52 and a presser bar 53. The separating knife and the presser bar are rigidly connected to each other, and both are .pivotable by means of the lever 55 around shaft 54. Movable roller 51 pivots around the same shaft, and is adapted to be lifted by means of the hook-shaped member 56, fixed to the lever 55, which engages the lever 57 carrying the roller 51 upon upward movement of lever 55.

Both rollers may have a diameter, say of mm., a length, say of 28 cm., and can be made of stainless steel. The peripheral speed of roller 50 is equal to that of the outlet roller pair of the preceding contacting apparatus. The separating knife 52 has generally the same shape as that represented in FIGURES 3 and 4. The presser bar 53 can be formed of a rod of stainless steel with a diameter, say of 3.5 mm., extending parallel to roller 50 over its full length. The operation of the apparatus is as'follows:

The image-receiving sheet 27 and light-sensitive sheet 26, both adhering to each other when leaving the contacting apparatus, are advanced towards the separating device. The light-sensitive sheet lying below, slightly leads the other. At the moment the sheets take the position as shown in FIGURE 5, the leading edge of sheet 26 actuates an electrical sensing device, such as a microswitch, to close the electrical circuit of a mechanism, e.g. a solenoid or the like (not shown), for lowering the lever 55. The lever 55 first assumes the position as indicated by the: broken lines in FIGURE 6. In this position, movable roller 51 will contact the leading edge of sheet 26 and press it against the periphery of the roller 50 so that it will be positively advanced by roller 50.

Continued lowering of lever 55, thereafter, has two effects. The member 56 releases the lever 57, so that the roller 51 remains resting under its own weight on the roller 50, and the knife 52 and the bar 53 will approach to the periphery 'of roller 50 so as to take finally a position as shown in FIGURE 6. Thus, the presser bar 53 presses both sheets at one place against the roller 50 while the knife 52 presses the light-sensitive sheet 26 at a second place, located about 90 away from the first one, against the roller 50. .Three actions now cooperate for the separation of the receiving sheet 27 from the lightsensitive sheet 26:

First, the effect of the knife 52, resting with its bevelled edge on the sheet 26 in front of the leading edge of sheet 27, so that the edge of the knife will engage the sheet edge;

Second, the sharp deflection of the sheets around the periphery of the roller 50 so that the inherent inclination to resist deflection will cause the sheet 27, which is only pressed at one point against the roller, to tend to separate from the sheet 26; and

Finally, the rubbing action of the presser bar 53 on the back side of the sheet 27 which will give the said sheet the tendency to curl towards the point of application of the friction.

The roller 50, together with roller 51 resting thereon,

to those used in connection with the embodiment of FIGURES 3 and 4.

After the sheets are fully separated, the sensing device de-energizes the electrical circuit, permitting lever 55 to return to its original inoperative position, under the influence of a return spring or other biasing means, if necessary. In so moving, lever 55 also disengages roller 51 from roller 50 by way of hook 56.

I claim:

1. In a copying device wherein image-transferring sheet material is intimately contacted by sheet-pressing means with an image-receiving sheet material and sutbsequently separated therefrom, a mechanism for separating sheets delivered thereto with the leading edge of one material projecting slightly forwardly of the leading edge of the other material, comprising a separating blade for penetrating between the contacting materials, transport means for delivering the sheet material while in contacting relation from said pressing means along a predetermined path to said separating blade, said transport means including a generally curved surface at least in the region adjacent said blade, means effective at least during separation to urge said blade towards said surface with at least the blade portion adjacent said surface extending generally tangentially thereof, said surface having a configuration such that said projecting portion of said one material extends at an angle to the normal surface curvature as the leading edge thereof reaches said blade, said blade engaging said angnlarly-exten-ding projecting portion of said one material and diverting one otfsaid materials from said predetermined path while allowing the other to proceed along said path.

2. A copy device for intimately contacting and subsequently separating image-tran-sfenring sheet material and image-receiving sheet material, said device comprising a transport surface movable along a circular path, means on said surface for gripping the leading edge portion of image-transferring material delivered thereto, means for presenting imageareceiving material to said surface with the leading edge thereof in slightly projecting relation to the exposed forward end of said image-transferring material, means for pressing the two materials into intimate contact while supported on said surface, a separating blade arranged along said path forward of said pressing means, said blade being resiliently urged into contact with said surface and extending angularly in the direction of movement from the locus of contact, said surface having a localized deformation therein underlying at least the center portion of the projecting end of said image receiving material for guiding said blade beneath said projecting end of said image-receiving material and over the gripped leading edge of said image transferring material whereby said blade strips the image-receiving material while the image-transferring material passes therebeneath.

3. The device of claim 2 wherein said deformation has the form of a projection whose surface is inclined upwardly and rearwardly relative to the remainder of said transport surface, the forward end of said projection being free of overlying image-receiving material.

4. The device of claim 2 wherein said separating blade in plan configuration tapers to a blunt surface-contacting end.

5. The device of claim 2 including means for applying processing liquid to the exposed face of said image transferring material in advance of said presenting and pressing means.

6. Apparatus for pressing together and subsequently separating image-transferring sheet material and imagereceiving sheet material comprising a transport cylinder having a surface thereof of peripheral extent sufiicient to support said material, said cylinder being rotated about its axis, first guide means adjacent one point on the cylinder periphery for presenting the leading edge of said image-transferring sheet material to the cylinder surface, gripping means on the cylinder for engaging the leading edge so presented so that said material rotates with said cylinder, second guide means adjacent a subsequent point on the cylinder periphery for presenting the leading edge of said image-receiving sheet material to said cylinder in slightly leading relation to the gripped edge of said imagetransferring material, pressing means adjacent said second guide means for pressing said materials together while supported on said surface, and a separating knife mounted adjacent said cylinder periphery intermediate said pressing means and said first guide means, said knife extending at an opposed angle relative to said surface and its direction of movement and urged into contact therewith over at least a portion of its edge, said surface having a limited discontinuity therein immediately preceding said gripping means at least at a transverse locus corresponding to the contacting knife end portion, said discontinuity maintaining the corresponding leading edge portion of said image-receiving material in generally displaced position relative to the underlying-surface to admit the knife edge portion therebeneath, said discontinuity terminating in close proximity to the gripped edge O f s-aid image-transferring material and in elevated relation thereto to direct said knife edge portion thereover.

7. A method of contacting and separating adherent sheet material comprising the steps of conveying one sheet material on a supporting surface while positively gripping the leading edge of said material, applying a second sheet material on said surface in intimate contact-ing relation to said first material with the leading end of said second material projecting slightly forwardly of the gripped leading end of said first material, maintaining at least the mid-portion of said forwardly projecting end of said second material displaced from said surface, and guiding a resilient separating blade beneath the displaced portion of said second material and over the gripped edge of said first sheet material, said blade extending over the width of said material generally transversely of said surface being urged into contact therewith, and projecting in opposed angular relationship to the direction of movement thereof.

8. A sheet stripping device for separating two superposed, intimately contacting sheet-s delivered with the leading edge of one sheet in leading relation to the leading edge of the other from a cont-acting uni-t having a contacting pair of delivery rollers, said device comprising a supp-orting surface adapted to be arranged in proximity to said delivery rollers to receive said sheets advanced thereby, an arcuate extension at one end of said surface, the sheet in leading relation contacting said surface, a resilient separating knife arranged on the side of said sheets remote from said sheet in leading relation for movement to and from an operative position with its edge urged towards said extension-from and to an inoperative position spaced therefrom, said knife at least adjacent its edge extending generally tangentially of said extension at an opposed angle with respect thereto, said edge being urged against said extension at a point spaced from the termination of said supporting surface a distance less than that between the leading edges of said sheets, said knife being moved to operative position as the sheet in trailing relation approaches said extension to contact and deflect the leading edge portion of the sheet in leading relation and, as said sheets continue to advance, penetrate therebet'ween to separate the same, and roller means for engaging a separated sheet portion to continue advance of the sheets after emergence from said pair of delivery rollers.

9. A device as in claim 8 wherein the planar surface has a length exceeding the length of said sheets and including positive sheet feeding means along said surface intermediate said pair of delivery rollers and said ar-cuate extension.

10. A device as in claim 9, wherein said knife extends transversely of the direction of advance of said sheets a distance at least equal to the width of the sheets and tapers from said extent to a blunt, rounded end at the edge urged into contact with said extension.

11. A device as in claim 8 including means actuated by the advance of said sheets for moving said knife to operative position in timed relation to the approach of the leading edge or said sheet in trailing relation to said arcuate extension.

12. A sheet separating device for separating two superposed, intimately contacting sheets delivered with the leading edge of one sheet in leading relation to the leading edge of the other from a contacting unit having a pair of contacting delivery rollers, said device comprising a driven first roller arranged to receive the sheets as delivered, at least one second roller cooperating with said driven roller, said second roller being normally spaced away from said first roller and adapted to be depressed into contact therewith to positively grip and advance the sheet in leading relation, a presser bar movable to wrap said sheets around an arc of said first roller in advance of the locus of contact between said rollers while the same grip said sheet in leading relation, and a resilient separating knife movable towards said first roller to contact the leading portion of the sheet in leading relation along the arc formed by said presser bar, at least the edge portion of said knife extending generally tangentially of said are at an opposed angle with respect to the advance of said sheet to penetrate between said sheets and separate the same as said sheet in leading relation is positively advanced.

13. The device of claim 12, wherein said presser bar and said knife are carried on a common support for simultaneous movement.

References Cited by the Examiner UNITED STATES PATENTS NORTON ANSHER, Primary Examiner.

C. B. PRICE, Assistant Examiner.

Stievenart et a1 -89

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4932644 *May 8, 1989Jun 12, 1990The Mead CorporationSheet feeding process
US5141584 *Nov 27, 1991Aug 25, 1992Polaroid CorporationApparatus and method for controlling the delamination of a laminate
US5169476 *Nov 27, 1991Dec 8, 1992Polaroid CorporationApparatus and method for delamination of a laminate
US5340430 *Sep 26, 1991Aug 23, 1994Maschinenfabrik Goebel GmbhSystem for handling a waste web of a web laminate
US5863374 *Mar 24, 1995Jan 26, 1999Silveira; Frank S.Method and apparatus for peeling a laminate
Classifications
U.S. Classification396/580, 271/311, 271/285, 396/612
International ClassificationG03D9/00
Cooperative ClassificationG03D9/00
European ClassificationG03D9/00