US3770554A

US3770554A - Apparatus for splitting a softenable film comprising bite rollers

Info

Publication number: US3770554A
Application number: US00160187A
Authority: US
Inventors: B Jones; W Goffe; J Blackert
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1971-07-06
Filing date: 1971-07-06
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06

Abstract

Donor and receiver webs are advanced by a common drive mechanism from supply reels through a film splitting housing. The donor web carries a film layer having marking particles dispersed in depth in complementary imagewise configurations within the film layer. The webs and film layer are laminated at a bite mechanism inside the housing and the webs are separated as they leave the bite mechanism. The film layer is softened at the time of the lamination and separation and splits into separate layers adhering to each web. The split occurs between the complementary imagewise configurations of marking particles thereby yielding positive and negative images on the two webs.

Description

United States Patent 1 Jones et al.

[111 3,770,554 Nov. 6, 1973 APPARATUS FOR SPLITTING A SOFTENABLE FILM COMPRISING BITE ROLLERS 1 [73] Assignee: Xerox Corporation, Rochester, N.Y.

{22] Filed: July 6, 1971 [21] Appl. No.: 160,187

Related U.S. Application Data [63] Continuation of Ser. No. 875,136, Nov. 10, 1969,

abandoned.

|52 U.S. Cl. 156/510, 156/584 51 Int. Cl ..B32b 31/00 58 Field of Search 156/584, 540, 254, 156/555, 510

[56] References Cited- UNITED STATES PATENTS 2,351,498 6/1944 Fowler 156/254 2,511,703 6/1950 Ettl 156/555 3,132,040 5/1964 Messance... 3,434,861 3/1969 Luc 156/254 Primary ExaminerDOuglas J. Drummond Att0rneylames J. Ralabate et al.

[57] ABSTRACT Donor and receiver webs are advanced by a common drive mechanism from supply reels through a film splitting housing. The donor web carries a film layer having marking particles dispersed in depth in complementary imagewise configurations within the film layer. The webs and film layer are laminated at a bite mechanism inside the housing and the webs are separated as they leave the bite mechanism. The film layer is softened at the time of the lamination and separation and splits into separate layers adhering to each web. The split occurs between the complementary imagewise configurations of marking particles thereby yielding positive and negative images on the two webs.

28 Claims, 6 Drawing Figures llI-Illl PATENTEUxu-v 6 I975 3.770.554

SHEET 1 [IF 4 F/GZ 1 INVENTORS ILLIAM L. GOFFE 9R A JONES PATENTEnunv sum (BI-[70.554

SHEET 30F 4 APPARATUS FOR SPLITTING A SOFTENABLE FILM COMPRISING BITE ROLLERS CROSS-REFERENCES TO RELATED APPLICATIONS This application is a cont. of application Ser. No. 875,136 filed Nov. 10, 1969 now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a novel imaging system in which marking particles are selectively moved through a softenable layer under the influence of electrical forces. Specifically, this invention relates to apparatus for splitting a layer of softenable material that has previously experienced a migration of marking particles to different depths or levels within it. Splitting the softenable layer separates the migrated and unmigrated particles into two separate layers which conventionally comprise positive and negative images.

Recently, a migration imaging system capable of producing high quality images of high density, continuous tone and high resolution has been developed. Such migration imaging systems are disclosed in copending applications Ser. Nos. 837,780 and 837,591, filed June 30, 1969. An imaging member used in these new imaging systems is typically one of three configurations: (l) a layered configuration comprising a substrate, a layer of softenable material and a fracturable and preferably particulate layer comprising photosensitive material on or embedded at the upper surface of the softenable layer; (2) a binder structure in which photosensitive particles are dispersed in a softenable layer overcoating a substrate; or (3) an overcoated structure in which a layer comprising photosensitive particles is sandwiched between first and second layers of softenable material on a substrate.

Softenable as used herein is intended to mean any material which can be rendered more permeable thereby enabling particles to migrate through its bulk. Conventionally, changing permeability is accomplished by heat or solvent softening. Fracturable layer of material as used herein and in the copending applications, means any particulate, continuous, or semi-continuous layer of material which is capable of breaking up during development, thereby permitting portions of said layer to migrate toward the substrate or to be otherwise removed.

. A typical method of forming an image with one of the above described imaging members is to form a latent electrostatic image on the surface of the imaging member followed by development of that image. One way to form the latent image is to uniformly charge a surface of the imaging member and then expose it to a pattern of electromagnetic radiation such as visible light. Most development methods include softening the softenable layer (hereafter referred to as the film layer) to allow the photosensitive particles (generally the marking particles) to migrate toward the substrate thereby obtaining a distinct separation between exposed and non-exposed particles.

The present invention is concerned withsplitting a developed film layer wherein marking particles are already dispersed at different depths or levelswithin the film. Copening application Ser. No. 784,164, filed Dec. 16, 1968 sets forth various methods of dealing with developed films including splitting of the film to obtain positive and negative images. The present invention offers improvements over the splitting methods described in the copending applications by adding steps to the prior methods and by providing novel and efficient apparatus for performing the splitting operation.

Accordingly, it is an object of the present invention to improve the above identified particle migration imaging system. Specifically, it is an object of the present invention to devise novel means for efficiently separating a developed imaging member into layers bearing complementary images.

Another object of this invention is to devise apparatus for laminating a film layer between donor and receiver webs and for separating the webs to split the film layer.

Another object in keeping with the foregoing object is to devise improved means for uniformly dispensing the donor and receiver webs, with one web carrying the film layer to be split, for heating and compressing the webs and film and for separating the webs.

Yet another object of the invention is to soften and split a film layer in a dark environment to prevent disturbances of the images at the different levels in the film layer.

Still another object of the invention is to control the level at which a film layer splits when it is subjected to opposed forces.

Even a further object of this invention is to devise means for supporting, heating and rotating roller members for the compression and splitting of film layers.

The above and other objects of the present invention are accomplished by novel film splitting apparatus. The apparatus is designed to split a film layer deposited on a donor web (the substrate for the softenable layer) by heating or solvent softening the film, by compressing it between the donor web and a second or receiver web, forming a bond between the film and webs greater than the cohesive strength of the softened film, and by stripping the webs apart. One of the resulting split layers adheres to the donor web and the other to the receiver web yielding complementary images, i.e. a positive and a negative. The level within the film at which separation or splitting occurs is varied by controlling the temperature gradient across the filmlayer. The webs are uniformly fed from supply reels by stripping means that includes a common drive mechanism coupled to both web's. The webs are guided over input rollers into bite means where they are compressed by small diameter bite rollers uniquely joumaled in supporting jaw mem bers. The bite means is positioned inside a dark chamber. Heater elements inserted in the jaw members heat soften the film and a nozzle is available for solvent softening. Input and output rollers are supported on either side of the bite means in a manner that enables the angles between the webs entering and exiting the bite means to be changed with the exit angle controlling the forces effecting the splitting of the film layer.

DESCRIPTION OF THE DRAWINGS Other objects and features of the present invention will be apparent from the present description and the drawings which are: 7

FIG. 1 is a front elevation view of the present film splitting apparatus;

FIG. 2 is a side elevation view of the film splitting apparatus;

FIG. 3 is a cross-sectional view of the film splitting apparatus taken along lines 33 in FIG. 1;

FIG. 4 is an enlarged plan view of the bite means employed in the film splitting apparatus;

FIG. 5 is an enlarged side view of the bite means in FIG. 4; and

FIG. 6 is a schematic illustration of a film layer being split into two layers having marking particles dispersed in complementary imagewise configurations.

DESCRIPTION OF THE INVENTION The film splitter of the present invention includes the base 1, the back support 2, the housing 3, the stanchion 4, the hanger 5, the

input rollers

7 and 8, the jaw members 9 and 10, the

output rollers

12 and 13, the capstans 14 and 15 and the pressure gauge 17.

The

webs

18 and 19 are composed of, by way of example, transparent synthetic materials such as that commercially available under the trade name Mylar". Web 18 is designated the donor web because it initially carries the film layer to be split. The donor web and the film layer comprises a developed imaging member as described earlier. The film layer is typically a softenable material that has previously been softened during a development process to disperse marking particles in complementary imagewise configurations at different levels or depths within the film layer. The function of the film splitter is to sever the film layer at a level that separates the complementary images. The film layer is heat or solvent softened, sandwiched between the donor web and the receiver web and split into one layer adhering to the donor web and another layer adhering to the receiver web.

The foregoing operation is illustrated schematically in FIG. 6 wherein a donor web 40 carrying a developed film layer 41 is compressed against a receiver web 42 by bite rollers 43 and 44. The webs are laminated or compressed together to establish an adhesive bond between the film and webs that-is greater than the cohesive strength of the film at a level within the film separating the marking particles 46 from marking particles 47.

Particles

46 and 47 are arranged at two distinct levels by earlier exposure and development steps not part of the present invention. The webs are stripped apart as they leave the bite rollers severing the film into layer 48 adhering to the donor web and layer 49 adhering to the receiver web.

In the present invention the film layer is maintained in a light free environment by the housing 3 while it is softened to prevent the marking particles from migrating as during development. Similarly, means are used in the present invention to dissipate or neutralize any residual electric charge on the webs which might cause unwanted particle migration when the film is softened. In this regard, corotron 51 (FIG. 1) neutralizes charge by depositing charges on the donor web of a polarity opposite to that used in the development of the film layer.

Referring to FIG. 1,

webs

18 and 19 are threaded through the splitter between the supply reels 20 and 21 and the

fasteners

23 and 24 on the hanger. The webs pass through the

apertures

25 and 26 into the dark chamber within the housing 3. The webs are guided by the input rollers to a point of contact at the

bite rollers

28 and 29 mounted on the jaw members. The webs are guided from the bite rollers by the output rollers, are wrapped around the capstans and exit the housing via

apertures

30 and 31. The hanger travels upward on the stanchion to uniformly advance the webs for the film splitting operation. The hanger is driven by the motor 35 coupled to the hanger by means of the cable 33 carried on the pulleys 34 and 34a.

The housing 3 rests on the base 1 and has the back support 2 coupled to its rear wall. The back support provides means in which to mount the supply reels 20 and 21. These reels are coupled to shafts on the drag brakes 37 and 38 respectively and rotate to dispense the

webs

18 and 19. The drag brakes are magnetic devices which oppose but do not prevent the rotation of the reels and therefore help maintain a constant tension in the webs as they are unwound.

The capstans 14 and 15 are positioned relative to the output rollers and the

output apertures

30 and 31 to allow the

webs

18 and 19 to exit the housing without physically contacting the roof of the housing. Likewise, the idler rollers 57 and 58 are positioned relative to the supply reels and input rollers to permit the webs to enter the housing through

apertures

25 and 26 without physically contacting the walls of the housing.

The splitting of asoftened film layer is accomplished as the

webs

18 and 19 are uniformly advanced past the

bite rollers

28 and 29. The webs are wrapped over the output rollers and under the capstans to help separate the webs as they leave the bite rollers. The forces effecting splitting are those forces aligned with the horizontal components of the web velocities at the point where they leave the bite rollers. These forces can be altered for a constant web speed by changing the angle 0 (FIG. 6) between the webs. To do this, the output rollers are rotatably mounted by appropriate means at one end of the

pivotal members

52 and 53. The other end of the pivotal members are coupled to the back support 2 by the fasteners 54 and 55. The angle 0 is changed by merely loosening the fasteners 54 and 55 and rotating the pivotal members to a new location. The preferred magnitude for angle 0 varies with the thickness of the film layer, the speed of the web, the nature of the film material, the softness of the film, etc.

The

input rollers

7 and 8 are supported in a manner that permits the angle B (FIG. 6) formed between the webs as they approach the bite rollers to be varied. The

input rollers

7 and 8 are joumaled for rotation by appropriate means in one end of the

yokes

59 and 58. The other end of the yokes are coupled to the

undercarriages

62 and 63 by appropriate fasteners 64 and 65. The fasteners are loosened to change the angle of the yokes relative to the undercarriages and thereby to change the angle B. In addition, the angle B is varied by moving the

undercarriages

62 and 63 toward or away from each other. The undercarriages are slidably coupled by dovetails 84b (sloped mated surfaces) with the slide support 84. Pinion gears 61 are journaled for rotation in the undercarriages and are mated with the rack gear 66 extending the length of the slide support. (There is a hole in the slide support to permit the

webs

18 and 19 to pass to the bite rollers. Consequently, rack gear 66 is in two parts with one being coupled to the slide support 84 on either side of the hole cut out for the webs.) The positions of the undercarriages are changed by rotating the pinion gears 61. This is accomplished by inserting a screwdriver in a slot in the ends of the shaft on which the pinion gears 61 are mounted. One effect the angle B has on the splitting operation is to control the area exposed to direct contact with solvent vapor issued through a nozzle 67 positioned directly below the bite rollers. The angle B is also varied to make or avoid contact between the webs and the

pre-heat elements

68 and 69.

The

pre-heat elements

68 and 69 are electrical heating rods inserted within appropriate holders. The holdcrs are made from materials that are good conductors of heat and include hollow

cylindrical posts

68b and 69!) into which the heating rods are inserted. The cylindrical rollers 68c and 690 are rotatably fit over the posts and rotate upon making friction contact with the webs. The pre-heat elements raise the temperature of the webs and the film layer before they reach the bite rollers. Heat is also conveyed to the film at the bite rollers to maintain the film in a softened state or to increase the softened condition of the film. The electrical leads 71 and 72 couple the pre-heat elements to an appropriate electrical energy source.

The jaw members 9 and 10 and

bite rollers

28 and 29 comprise the bite means for compressing the webs and film. The two jaw members include respectively, the

carriages

71 and 72, the heating blocks 73 and 74 and the insulating

blocks

76 and 77. The carriages (FIG. 2) are slidably coupled to the slide support 84 by means of the dovetails 84a (mating sloped surfaces on the carriages and slide support.) The dovetail interlocking of the carriages and the slide support stabilizes the

bite rollers

28 and 29 and prevents them from skewing or otherwise moving relative to each other during the film splitting operation. In addition, the dovetail mounting permits the bite rollers to be repeatedly separated and returned to positions at which they are capable of contacting one another over substantially their entire length.

The carriages are also coupled to the slide support by means of rack and pinion gears. The rack gears 78 and 79 (FIG. 3) are fixedly coupled to the slide supports and extend along its length. Each carriage has pinion gears mated with the rack gears 78 and 79. The pinion gears 80 and 81 coupled to carriage 71 (FIG. 3) are typical of like gears coupled to carriage 72. The pinion gears are fastened to a shaft 83 which is in turn journaled for rotation in a carriage. A hole (mentioned earlier) is cut into the slide support between the rack gears 78 and 79 to permit the webs l8 and 19 passage to the bite rollers.

The left hand carriage 71 has an adjustment mechanism coupled to it comprising the knob 85 and threaded shaft 86. Thread on shaft 86 is mated with thread in the housing wall 87 and the right end of the threaded shaft is rotatably coupled to the carriage 71. Consequently, the threaded shaft moves the carriage from left to right when the knob is rotated clockwise and moves the carriage from right to left when the knob is rotated counterclockwise. The adjustment mechanism is means for controll ably moving the left hand carriage 71 along the

racks

78 and 79 along'a collision path with the right hand carriage 72.

Carriage 71 is moved to the left when the webs l8 and 19 are being threaded through the film splitter and is moved to the right during the splitting operation. The right hand carriage specifically the insulating block 77, collides with the pressure gauge 17 when it is moved to the right. The gauge is anchored against movement and typically has the right hand carriage 72 positioned in contact with it. When the left hand carriage 71 is moved to the right by the adjustment mechanism it forces the right hand carriage against the gauge 17. The gauge provides a read out of pressure exerted on the donor and receiver webs located between the

bite rollers

28 and 29. The compression pressure exerted on the film is typically in the range of 3 to 15 pounds per square inch (psi).

The rack and pinion gears, the dovetail interlocking of parts and adjustment means provide positive control over the movement and positioning of the

bite rollers

28 and 29. The ability to closely control and maintain the relative position or location of the bite rollers provides precise and constant control over the forces exerted on the

webs

18 and 19 and the film layer between them.

The heating blocks 73 and 74 are coupled directly to the insulating

blocks

76 and 77 respectively and are made from a material that is a good conductor of heat. The insulating

blocks

76 and 77 are mounted directly on the

carriages

71 and 72 respectively and are made from a material that is a poor conductor of heat. Preferably, the insulating blocks are made up of a plurality of laminated epoxy board. The insulating blocks confine the heat energy generated by the

heat elements

91 and 92 to the heating blocks and the bite rollers. The insulating blocks add to the efficiency of the film splitting apparatus and enable the carriages and other components to be handled without an operator receiving burns.

The

heating elements

91 and 92 are substantially the same devices as

elements

68 and 69 in that they are electrical heating rods of the type commercially available under the trade name Watlow Firerod. The electrical leads 96 couple the heating elements to an appropriate energy source. The heating elements are inserted into cores or holes 89 and 90 in the heating blocks. The heat energy generated by the heating elements is transmitted to the bite rollers and then to the film layers primarily by conduction through the body of the heating blocks. The heat energy produced by the heating elements is selected to be sufficient to lower the cohesive strenth of a film layer below the levels of the adhesive bonds between the film and the donor and receiver webs.

It has been found that the depth or level at which the film layer splits can be varied by changing the heat gradient across the film, e.g. heating one side of the film to a higher temperature than the other side. This is accomplished by varying the electrical current flow to the

heating elements

91 and 92 such that the temperature of one is greater than the other. Alternatively, one of the heating elements may be completely removed from the heating block. The film tends to split at a level closer to the web at the higher temperature. To repeat, the film'tends to split at a level relative to the center of the film that is adjacent the web at the higher temperature. The heat energy is transmitted to the film layer through the donor and receiver webs. Consequently, the temperature of the webs establishes the gradient across the film layer. it is possible therefore to employ the

pre-heat elements

68 and 69, the solvent nozzle 67 and the

heating elements

91 and 92 in a variety of ways to effect some particular heat gradient across the film layer. If only vapor softening is used splitting occurs on the average in the center of the film. The speed of the webs is also a factor to be considered since both heat and solvent softening are dependent upon the length of time to which the film is exposed to solvent or heat.

The

bite rollers

28 and 29 are mounted on the narrow or pointed ends of the heating blocks and their peripheries are the surfaces at which the jaw members collide. The bite rollers are joumaled for rotation by means that include the journal blocks 94 and 95 coupled by appropriate means to the heating blocks 73 and 74 respectively. The journal blocks have V-shaped grooves extending their width and in which the bite rollers are rotatably seated. The bite rollers are supported over most of their length by the journal blocks to prevent buckling or bowing of the bite rollerswhen subjected to the web compressing pressures. There are grooves at each end of a bite roller in which a turn or loop of a coil spring 93 is rotatably fit. The loops or turns 97 (4 total) act as a thrust bearing for the roller while each spring (4 total) is anchored to a heating block to act as a bias mechanism for holding or seating the bite rollers firmly in the V-grooves of the journal blocks. The V-shaped or tapered grooves are selected to permit the journal blocks to seat different diameter bite rollers and to minimize the friction surface contact with a bite roller while providing support against bending or other deformation. The V-shape groove is also selected because it is easily manufactured even for small diameter rollers.

The v grooves of the

joumal'blocks

94 and 95 are preferably coated with a low friction material such as Teflon to improve the ability of the bite rollers to rotate upon making friction contact with a moving web. Also, the journal blocks are typically made of a material that is a good conductor of heat. Although materials such as Teflon are relatively poor conductors of heat, heat is still efficiently conveyed to the bite rollers because the Teflon (or other low friction material) coating is relatively thin so as not to form a significant heat barrier between'the bite rollers and their journal blocks.

The diameter of a bite roller is generally in the order of from about l/32 inch to about one-half inch. The presently preferred diameter size is one-eighth inch. This small diameter is purposefully selected to minimize the effect of dirt, dust, and other foreign objects on the periphery of the bite rollers, on the webs and on the film. lf foreign objects are on the rollers, webs or film they create faults in the images and otherwise adversely affect the splitting of the film layer. The foreign objects alter the adhesive contact and distribution of forces between web and film and are unwanted discontinuities in the film and web sandwich structure. The closed housing 3 affords additional protection against dirt, dust and other foreign objects. Also, the journal blocks 94 and 95 contact a bite roller over its length and act to clean the surface of a roller as it rotates.

The small diameter bite rollers are also advantageous because they minimize the area on the film and webs to which a force is applied. Consequently, the presently preferred compression pressures of 3 to psi are attainable with the exertion of a relatively small force between the bite rollers. Furthermore, the small diameter of the bite rollers permits a more rapid separation of the webs. The rapid web separation minimizes the formation and size of film strands stretching between the webs after leaving the bite rollers. On the other hand, the small roller diameters create the practical problems of having sufficient structural strength to resist bowing or bending under the compression pressures and of having bearings that allow the bite rollers to freely rotate upon making friction contact with a moving web,

or alternatively, to being motor driven. These problems are overcome by the presently used apparatus for journaling and supporting the bite rollers.

Appropriate plumbing is coupled to the nozzle 67 for pumping the solvent (normally a gas) from a supply reservoir and for directing it onto the webs. Nozzle 67 consists of a pipe substantially the same length of the bite rollers having a plurality of holes drilled in the line along its length. The holes are oriented relative to the bite rollers to direct the solvent to the nip between the bite rollers. The solvent vapor apparatus is provided principally as an alternate means for film softening but may also be used jointly with the heat softening apparatus, i.e.

heating elements

68, 69, 91 and 92.

In operation, supply reels 20 and 21 are mounted onto the shafts of the drag brakes 37 and 38. The donor web 18 is pulled from reel 20 and threaded through the machine to the fastener 23 on hanger 5. Likewise, the receiver web 19 is pulled from reel 21 and threaded through the machine to fastener 24. The hanger is initially located at its lowermost position on the stanchion 4. The left jaw member is moved to the left to provide space between the bite rollers for the threading operation. Once the webs are threaded, the adjustment means is used to compress the webs between the bite rollers. A leader is often coupled to each web to facilitate the threading of the webs and to afford them some degree of protection. A front panel (not shown) is removed from the housing to allow the operator access to the various rollers in order to thread the webs. Before the front panel is replaced, the pressure exerted on the webs is monitored on the readout scale of the pressure gauge 17. The pressure is of course adjusted to some predetermined level by means of the adjustment knob and shaft 86. With this done, the front panel is mounted on the housing thereby shielding the film and webs from light. The closed housing defines a dark chamber in which the splitting operation takes place.

Conventionally, the

heating elements

91 and 92 are energized at a much earlier time to allow the heating blocks to reach predetermined operating temperatures. Likewise, the

pre-heat elements

68 and 69 are energized at an earlier time to bring the holders supporting them to a desired operating temperature.

Next, the electric motor 35 is energized propelling the hanger upward on the stanchion. The webs are unwound from the supply reels at uniform rates because, for one, they are coupled to a common drive mechanism. If solvent softening is being used, a gas solvent is directed from nozzle 67 onto the moving web. The webs are heated as they travel past the

pre-heat elements

68 and 69 and again when they are in the nip between the bite rollers. The softened film is compressed between the webs forming a strong adhesive bond with each web. Immediately after the webs pass the bite rollers they separate toward the output rollers. The forces at separation split the film layer substantially down the middle. (The location of the split may be shifted right or left of center by appropriate heat gradients as explained earlier.) Typically, the film, now on both webs, hardens by the time it passes over the

output rollers

12 and 13 and clearly before it comes into contact with the capstans 14 and 15. The hardened film layers may once again be softened by heat or solvent after the webs pass the capstans. (Heating elements 98 and 99 are illustrative apparatus). This subsequent softening of the split film layers smooths out ragged surfaces of the film and permits randomly dislocated marking particles to move closer to the webs.

Finally, the webs exit the housing and are available for immediate visual inspection. The height of the stanchion 4 is sufficient for the hanger to advance the webs from a position below the bite rollers to a position well outside the housing. At this point in time, the splitting operation may be continued by: severing the webs at a point just outside the

exit apertures

30 and 31; lowering the hanger to its starting position; coupling the threaded webs extending from the housing to

fasteners

23 and 24, and; energizing the electric motor 35.

What is claimed is:

l. A bite roller apparatus comprising:

first and second opposed, axially parallel bite rollers having diameters in the range from about 1/32 inch to about one-half inch;

first and second journal blocks, said first and second bite rollers each rotatably peripherally supported I along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively;

means for advancing at the same speed a first web and a second web, each respectively contacting an opposite surface of a softenable film, between said first and second bite rollers; and

means for separating the webs exiting from said bite rollers whereby the softenable film may be split leaving a first thin softenable film on said first web and leaving a second thin softenable film on said second web.

2. The apparatus of claim 1 additionally comprising means for applying a softening medium to said softenable film.

3. The apparatus of claim 2 wherein said medium applying means comprises means for applying a solvent to said softenable film to soften said film prior to advancing said film and webs between said bite rollers.

4. The apparatus of claim 2 wherein said medium applying means comprises means for heating said softenable film to soften said film prior to advancing said film and webs between said bite rollers.

5. The apparatus of claim 4 wherein said means for heating comprises first and second means for heating, said first and second means for heating, respectively, located contiguous the paths of said first and second webs, to heat said webs prior to advancing said webs between said bite rollers.

6. The apparatus of claim 2 wherein the means for advancing said webs between said bite rollers is a single drive means capable of being directly coupled to each web.

7. The apparatus of claim 6 wherein said single drive means includes a hanger for coupling directly to said webs, said hanger being supported for travel along a linear path.

8. The apparatus of claim 7 additionally comprising first and second output rollers and first and second capstans between said hanger and said first and second bite rollers, for separating said webs exiting said bite rollers.

9. The apparatus of claim 8 additionally comprising means for varying the position of the output rollers relative to the bite rollers for varying the angle of separation between the webs exiting the bite rollers.

10. The apparatus of claim 1 additionally comprising means for applying a softening medium to at least one of said thin soft-enable films thereby smoothing the free surface of said thin film after said webs exit said bite rollers and are separated, said means for softening being contiguous the path of at least one of said webs.

l 1. The apparatus of claim 10 wherein said means for applying a softening medium comprises a first and second means for applying a softening medium for softening said thin softenable films, said first and second means for applying a softening medium, respectively, contiguous the paths of said first and second webs, to smooth the free surfaces of said thin softenable films.

12. The apparatus of claim 10 wherein said means for applying a softening medium comprises means for heating said thin softenable film.

13. The apparatus of claim 10 wherein said means for applying a softening medium comprises means for applying a solvent for said thin softenable film to said film.

14. The apparatus of claim 2 additionally comprising a first supply reel having said first web wound thereon, and a second supply reel having said second web wound thereon.

15. The apparatus of claim l4 additionally comprising drag means coupled to said supply reels for applying tension to said webs as they are advanced through said apparatus.

16. The apparatus of claim 14 additionally comprising first and second input rollers positioned between said first and second supply reels and said first and second bite rollers, respectively, for varying the angle between said webs as said webs approach said bite rollers.

17. The apparatus of claim 16 additionally comprising means for applying a solvent to said softenable film, said means for applying positioned to direct said solvent into the angle between said webs, and wherein said softenable film is located on the surface of one of said webs, said surface within the angle between said webs into which said solvent is directed.

18. A bite roller apparatus comprising:

first and second journal blocks, said first and second bite rollers each rotatably peripherially supported along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively;

a supporting slide member; and

means for supporting said journal blocks including dove-tail coupling between said means for supporting said journal blocks and said supporting slide member.

19. Apparatus for splitting a softenable film between a pair of webs contacting the opposite surfaces of said film, said film containing at least two images of migration marking material, said images at least in part spaced apart across the thickness of said softenable I means for applying a softening medium to said softenable film; and

means for advancing at the same speed said webs, be-

tween said first and second bite rollers, and means for separating the webs exiting from said bite rollers thereby splitting said softenable film leaving a first thin softenable film containing one image on one web and a second thin softenable film containing another image on the other web.

20. The apparatus of claim 19 wherein said means for applying a softening medium comprises means external to said bite rollers for heating said bite rollers, said heating means coupled to said journal blocks.

21. The apparatus of claim 19 wherein said means for applying a softening medium comprises means for applying a solvent for said softenable film to said film prior to advancing said film and webs between said bite rollers.

22. The apparatus of claim 19 wherein said means for advancing said webs comprises a single drive means capable of being directly coupled to each web.

23. The apparatus of claim 19 wherein the softenable film to be split is located on the surfaces of one of said webs, and said apparatus additionally comprises means for electrically discharging said web and film before advancing said film past the means for applying a softening medium and said bite rollers, said means for discharging located contiguous the path of said web which supports said softenable film to be split.

24. The apparatus of claim 19 additionally comprising a dark chamber enclosing at least said bite rollers,

said dark chamber for preventing light from impinging upon said softenable film while said film is in its softened condition.

25. Apparatus for splitting a softenable film of thickness in the range from about one-half micron to about 16 microns between a pair of webs contacting the opposite surfaces of said film, said film containing at least two images of migration marking material, one of said images contiguous one surface of said film, and another image contiguous the other surface of said film, and said migration marking material comprising particulate material of average particle size in the range from about 0.1 microns to about 2 microns, said apparatus comprising: 7

first and second opposed, axially parallel bite rollers having diameters in the range from about 1/32 inch to about one-half inch, and first and second journal blocks, said first and second bite rollers each rotatably peripherially supported along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively, and said rollers coupled with said journal blocks by means including bias springs coupled between each bite roller and its respective journal block,

means for applying a softening medium to said softenable film; and

a single drive means capable of being directly coupled to each web for advancing said webs at the same speed between said first and second bite rollers, and means for separating the webs exiting from said bite rollers thereby splitting said softenable film leaving a first thin softenable film containing one image of migration marking material on one web and a second thin film of migration marking material containing another image of migration marking material on the other web.

26. The apparatus of claim 25 wherein said means for applying a softening medium to said softenable film comprises means external to said bite rollers for heating at least one of said bite rollers, said heating means coupled to the respective journal block wherein said one bite roller is supported, said heating means capable of heating at least said one bite roller by conduction through said journal block.

27. The apparatus of claim 26 comprising means external to said bite rollers for heating said bite rollers, said heating means coupled to said journal blocks and capable of heating said bite rollers by conduction through said journal blocks.

28. The apparatus of claim 25 wherein said means for applying a softening medium to said softenable film comprises means for applying a solvent for said softenable film to said film prior to advancing said webs between said bite rollers.

Claims

1. A bite roller apparatus comprising: first and second opposed, axially parallel bite rollers having diameters in the range from about 1/32 inch to about one-half inch; first and second journal blocks, said first and second bite rollers each rotatably peripherally supported along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively; means for advancing at the same speed a first web and a second web, each respectively contacting an opposite surface of a softenable film, between said first and second bite rollers; and means for separating the webs exiting from said bite rollers whereby the softenable film may be split leaving a first thin softenable film on said first web and leaving a second thin softenable film on said second web.

11. The apparatus of claim 10 wherein said means for applying a softening medium comprises a first and second means for applying a softening medium for softening said thin softenable films, said first and second means for applying a softening medium, respectively, contiguous the paths of said first and second webs, to smooth the free surfaces of said thin softenable films.

15. The apparatus of claim 14 additionally comprising drag means coupled to said supply reels for applying tension to said webs as they are advanced through said apparatus.

18. A bite roller apparatus comprising: first and second opposed, axially parallel bite rollers having diameters in the range from about 1/32 inch to about one-half inch; first and second journal blocks, said first and second bite rollers each rotatably peripherially supported along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively; a supporting slide member; and means for supporting said journal blocks including dove-tail coupling between said means for supporting said journal blocks and said supporting slide member.

19. Apparatus for splitting a softenable film between a pair of webs contacting the opposite surfaces of said film, said film containing at least two images of migration marking material, said images at least in part spaced apart across the thickness of said softenable film, said apparatus comprising: first and second opposed, axially parallel bite rollers having diameters in the range from about 1/32 inch to about one-half inch, and first and second journal blocks, said first and second bite rollers each rotatably peripherally supported along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively; means for applying a softening medium to said softenable film; and means for advancing at the same speed said webs, between said first and second bite rollers, and means for separating the webs exiting from said bite rollers thereby splitting said softenaBle film leaving a first thin softenable film containing one image on one web and a second thin softenable film containing another image on the other web.

24. The apparatus of claim 19 additionally comprising a dark chamber enclosing at least said bite rollers, said dark chamber for preventing light from impinging upon said softenable film while said film is in its softened condition.

25. Apparatus for splitting a softenable film of thickness in the range from about one-half micron to about 16 microns between a pair of webs contacting the opposite surfaces of said film, said film containing at least two images of migration marking material, one of said images contiguous one surface of said film, and another image contiguous the other surface of said film, and said migration marking material comprising particulate material of average particle size in the range from about 0.1 microns to about 2 microns, said apparatus comprising: first and second opposed, axially parallel bite rollers having diameters in the range from about 1/32 inch to about one-half inch, and first and second journal blocks, said first and second bite rollers each rotatably peripherially supported along substantially the entire axial length of the pressure bearing portion of said roller in a groove in each of said first and second journal blocks, respectively, and said rollers coupled with said journal blocks by means including bias springs coupled between each bite roller and its respective journal block, means for applying a softening medium to said softenable film; and a single drive means capable of being directly coupled to each web for advancing said webs at the same speed between said first and second bite rollers, and means for separating the webs exiting from said bite rollers thereby splitting said softenable film leaving a first thin softenable film containing one image of migration marking material on one web and a second thin film of migration marking material containing another image of migration marking material on the other web.