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Publication numberUS3642364 A
Publication typeGrant
Publication dateFeb 15, 1972
Filing dateNov 14, 1969
Priority dateNov 14, 1969
Also published asDE2055518A1
Publication numberUS 3642364 A, US 3642364A, US-A-3642364, US3642364 A, US3642364A
InventorsEgnaczak Raymond K
Original AssigneeXerox Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Transfer apparatus
US 3642364 A
A mechanism for carrying sheets of support material past a wetting station and an electrophoretic image transfer station using grippers and lifter fingers to engage and disengage the sheet. The mechanism includes a roller capable of holding an electrical potential and a brush to contact and clean contaminating material from the roller. The entire mechanism can be moved into and out of contact with the member from which images will be electrophoretically transferred. Optionally, the image-bearing support material passes a fixer to heat the image for drying it and bonding it to the support material.
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Claims  available in
Description  (OCR text may contain errors)

nited States Patent Egnaczak [54] TRANSFER APPARATUS [72] Inventor: Raymond K. Egnaczak, Williamson, NY. [73] Assignee: Xerox Corporation, Rochester, NY.

[22] Filed: Nov. 14, 1969 [21] Appl. No.: 876,929

[52] U.S. Cl ..355/3, 15/1.5, 118/223, 118/637, 355/15 [51] Int. Cl. ..G03g 15/00, G03g 15/10 [58] Field ofSearch ..355/3, 15, 14; 15/1.5; 118/70,

[56] References Cited UNIT ED STATES PATENTS 3,169,081 2/1965 Nelson et a1.

668,562 2/1901 Imschenetzky. 1 18/224 1,107,773 8/1914 Ford .118/231 X 510,630 12/1893 Dean.... ..ll8/231 533,443 2/1895 Dejonge ..l18/231 X 3,079,483 2/1963 Codichini et al ..1 18/642 X Feb. 15,1972

Primary Examiner-Samuel S. Matthews Assistant Examiner-Robert P. Greiner Attorney-James J. Ralabate, David C. Petre and Barry Jay Kesselman [57] ABSTRACT A mechanism for carrying sheets of support material past a wetting station and an electrophoretic image transfer station using grippers and lifter fingers to engage and disengage the sheet. The mechanism includes a roller capable of holding an electrical potential and a brush to contact and clean contaminating material from the roller. The entire mechanism can be moved into and out of contact with the member from which images will be electrophoretically transferred. Optionally, the image-bearing support material passes a fixer to heat the image for drying it and bonding it to the support material.

17 Claims, 13 Drawing Figures PAIENIEUFEB 1 5 I972 SHEET 1 OF 7 INVENTOR.


SHEEI u or 7 A umuw v 4 PAIENIEBFEB 15 m2 sum 5 OF 7 vwv PATENTEDFEB 15 I972 SHEET 6 [IF 7 wrv TRANSFER APPARATUS This invention relates to sheet handlingand more particularly to image transfer mechanisms.

Recently, a new invention was disclosed for forming black and white or full color images through the use of photoelectrophoresis. The invention described in U.S. Pat. Nos. 3,384,488; 3,384,566 and 3,383,993 all issued on May 21, I968 discloses a system where photoelectrophoretic particles migrate in image configuration providing a visual image at one or both of two electrodes between which the particles are placed in suspension. The particles are photosensitive and apparently undergo a net change in charge polarity or a polarity alteration by interaction with one of the electrodes upon exposure to activating electromagnetic radiation. No other photosensitive elements or materials are required. Mixtures of two or more differently colored particles can secure various colors of images. Particles in these mixes may have overlapping or separate spectral response curves and are usable in subtractive color synthesis. The particles will migrate from one of the electrodes under the influence of an electric field when struck with energy of a wavelength within the spectral response of the colored particles. Apparatus has been invented to better utilize the above process. For example, U.S. Pat. No. 3,427,242 issued Feb. II, 1969 describes a continuous apparatus embodiment of the above process.

Both the process and apparatus can produce images that are capable of being transferred to support materials of various composition. It has been found that final images transferred to sheets of support material are particularly convenient. In some instances a more or less permanent bonding of the images transferred to the support sheet is desirable.

Therefore, an object of this invention is to achieve the above-desired results. Another object of the invention is to improve transfer of images.

Yet another object of the invention is to improve fixing of transferred images. Still another object of this invention is to coat support material prior to transfer of images.

A further object of the invention is to contact an image-carrying member when it presents an image to be transferred. Another object is to clean the transfer mechanism from contaminants. Still another object is to heat fix a previously transferred image.

These and other objects of this invention are accomplished by periodically contacting an image-carrying member with a sheet of support material gripped on an electrically biasable transfer member and moved past a coating means and then releasing the sheet for optional movement through an imagefixing means for producing a toughened surface on the imagebearing support material.

The invention herein is described and illustrated in a specific embodiment having specific components listed for carrying out the functions of the apparatus. Nevertheless, the invention need not be thought of as being confined to-such a specific showing and should be construed broadly within the scope of the claims. Any and all equivalent structures known to those skilled in the art can be substituted for specific apparatus disclosed as long as the substituted apparatus achieves a similar function. It may be that other processes or apparatus will be invented having similar needs to those fulfilled by the apparatus described and claimed herein and it is the intention herein to describe an invention for use in apparatus other than the embodiment shown.

The advantages of the invention will become apparent to those skilled in the art after reading the following description taken in conjunction with the accompanying drawings, wherein:

FIG. I schematically illustrates an embodiment of a machine utilizing this invention;

FIG. 2 is a top view partly broken away and with dotted lines to show hidden parts of thetransfer assembly;

FIG. 3 is a rear view of the assembly of FIG. 2 with parts broken away and dotted;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

V trodes" FIG. 5 is a top view of the transfer roller when rotated from the position of FIG. 4;

FIG. 6-is a fragmentary view sectioned along line 6-6 of FIG. 2;

FIG. 7 is a side view of cams to operate the prewet and gripping mechanisms of the transfer assembly as viewed from line 7-7 of FIG. 2;

FIGS. 8, 9 and 10 are sequential illustrations of the gripping and lifter segments of the transfer assembly operating relative to each other to remove a sheet of support material;

FIG. 11 is a side view from line l1--Il of FIG. 6 but with the transfer roll rotated 180 from that shown in FIG. 6;

FIG. 12 is a sectional view of the fixing assembly viewed along the path taken by the support material; and

FIG. 13 is a sectional view of the fixing assembly taken near the exit ofthe support material from the assembly.

OPERATION OF BASIC SYSTEM A detaileddescription of the operation and theories relating to the actual imaging system automated by this invention and discussing the interaction of the photoelectrophoretic particles in the suspension used for image formation is found in the above-cited patents. The imaging system therein described and which can be employed in the apparatus described herein operates by producing electromagnetic radiation in image configuration to which the individual photoelectrophoretic particles within the suspension are sensitive. The activating radiationand an electric field across the imaging suspension combine between two electrodes in the imaging area. An electrode referred to as the transparent injecting electrode is maintained electrically positive relative to imaging elecinterfacing with it as the imaging area across the photosensitive suspension. Therefore, particles within the suspension that are negatively charged will be attracted to the relatively positive, transparent injecting electrode.

The"injecting electrode is so named because it is thought to inject electrical charges into activated photosensitive particles during imaging. The term photosensitive for the purposes of this invention refers to the property of a particle which, once attracted to the injecting electrode. will alter its polarity and migrate away from the electrode under the influence of an applied electric field when exposed to activating electromagnetic radiation. The term suspension" may be defined as a system having solid particles dispersed in a solid, liquid or gas. Nevertheless, the suspension used in the embodiment of. this invention described herein is of the general type having a solid suspended in a liquid carrier. The term imaging electrode is used to describe that electrode which interfaces with the injecting electrode through the suspension and which once contacted by activated photosensitive particles will not inject sufficient charge into them to cause them to migrate from the imaging electrode surface. The imaging zone." or imaging area is that zone between two electrodes where photoelectrophoretic imaging occurs.

The particles within the suspension are generally insulating when not struck by activating radiation within their spectral response curve. The negative particles come into contact with or are closely adjacent to the injecting electrode and remain in that position under the influence of the applied electric field until they are exposed to activating electromagnetic radiation. The particles near the surface of the injecting electrode make up the potential imaging particles for the final image to be reproduced thereon. When activating radiation strikes the particles, it makes them conductive creating an electrical junction of charge carriers which may be considered mobile in nature. The negative charge carriers of the electrical junction orient themselves toward the positive injecting electrode while the positive charge carriers move toward the imaging electrode. The negative charge carriers near the particle-electrode interface at the injecting electrode can move across the short distance between the particle and the surface of the electrode leaving the particle with a net positive charge. These polarityaltered, net positively charged particles are now repelled away from the positive surface of the injecting electrode and are attracted to the negative surface of the imaging electrode. Accordingly, the particles struck by activating radiation of a wavelength with which they are sensitive, i.e., a wavelength which will cause the formation of an electrical junction within the particles, move away from the injecting electrode to the imaging electrodeleaving behind only particles which are not exposed to sufficient electromagnetic radiation in their responsive range to undergo this change.

Consequently, if all the particles in the system are sensitive to one wavelength of light or another and the system is exposed to an image with that wavelength of light, a positive image will be formed on the surface of the injecting electrode by the subtraction of bound particles from its surface leaving behind particles in the unexposed areas only. The polarities on the system can be reversed and imaging will occur. The system may be operated with dispersions of particles which initially take on a net positive charge or a net negative charge.

The imaging suspension may contain one, two, three or more different particles of various colors having various ranges of spectral response. In a monochromatic system the particles included in the suspension may be of any color and produce any color and the particle spectral response is relatively immaterial as long as there is a response in some region of the spectrum which can be matched by a convenient radiation exposure source. In polychromatic systems the particles may be selected so that particles of different colors respond to different wavelengths For photoelectrophoretic imaging to occur, these steps (not necessarily listed in the sequence that they occur) take place: (1) migration of the particles toward the injecting electrode due to the influence of the field, (2) the generation of charge carriers within the particles when struck with activating radiation, (3) particle deposition on or near the injecting electrode surface, (4) phenomena associated with the forming of an electrical junction between the particles and the injecting electrode, (5) particle charge exchange with the injecting electrode, (6) electrophoretic migration toward the imaging electrode, and (7) particle deposition on the imaging electrode. This leaves a positive image on the injecting electrode.

After the image is formed on the injecting electrode, the electrode may be brought into interface with a transfer member which has a charge polarity opposite to that of the imaging electrode. The injecting electrode is now maintained negative relative to the transfer member. The particles having a net negative charge will be attracted to the relatively positive transfer member. If a support material is interposed between the transfer member and the particle image, the particles will be attracted to the support material. Therefore, a photographically positive image can be formed on any support material.

THE MACHINE COMPONENTS Referring now to FIG. 1, a preferred embodiment for an automated machine to produce images according to the aforementioned process is shown. An injecting electrode 1 forms a portion of a transparent cylinder member held in a housing 2 and is journaled for rotation in the direction indicated by the arrow about a shaft 3. The injecting electrode 1 is made up of a layer of optically transparent glass 4 overcoated with a thin optically transparent layer 5 of tin oxide or other electrically conducting material. A particular material suitable for this electrode is available under the name of NESA glass manufactured by Pittsburgh Plate Glass Company, Pittsburgh, Pa. The injecting electrode 1 is formed as a portion of a cylinder housed within the metal housing frame 2.

The machine shown schematically in FIG. 1 is positioned where the injecting electrode cylinder portion is about to be rotated in a predetermined path to a cleaning station labeled A whereat a plurality of cleaning members such as belts 6, 7 and 8 contact the conductive surface 5 of the injectingelectrode. On the opposite side of the injecting electrode held stationary within the machine frame are lamps 9, l0 and 11 juxtaposed to the belts 6, 7 and 8 respectively. When activated, the lamps send floodlight illumination through the transparent injecting electrode at the contact areas between the electrode and the cleaning belts. Each of the belts are activated by one of the cylinders 12, .13 and 14 to contact the injecting electrode 1. These cylinders operate to press the belts against the conductive surface of the injecting electrode in order to clean it.

The next station in the path of movement of the injecting electrode is the imaging station B. Here, on the first pass of the injecting electrode 1 through station B the first imaging member, the imaging electrode 16 interfaces with the conductive surface-5 of the injecting electrode 1.

The optical system at station C projects an image to the imaging zone between the electrodes 1 and 16 at station B. The optical system has a lamp carriage l7 journaled at an axis 18 to oscillate in a path indicated by the arrows. A document 20 is positioned at the platen 19. The lamps are shown at the start of scan position and as the injecting electrode 1 passes through the imaging area at station B the lamps move across the platen 19 projecting an image at station B through suitable mirrors 21-23, a lens 24 and the transparent electrode 1.

The imaging'electrode roller 16 moves in rolling interface relation with the conductive surface 5 of the injecting electrode l and functions both to supply suspension to the injecting electrode and to image that suspension between the injecting electrode surface 5 and the surface of the electrode 16.

The injecting electrode continues to rotate at a constant velocity through a complete rotation of the predetermined path. It travels without interacting with any elements located around the periphery of the path until it again reaches station B at the imaging zone. Now, however, the injecting electrode 16 has been moved out of its interfacing position by operation of a cylinder 25 which lowers the electrode 16 and the housing 26 supporting it. Further, a cylinder. 27 moves a carriage 28 along a horizontal path carrying with it the housing 26 which supports the imaging electrode 16. Also moved in the carriage 28 is a second imaging member, the imaging electrode 29 within a housing 30 maintaining it. A cylinder 31 operates through an eccentric 32 to raise the housing 30 and the second imaging electrode 29 at the imaging zone at the imaging station B of the machine. The second imaging electrode 29 moves in rolling interface with the injecting electrode surface 5 as that surface passes through the imaging station B. At this time the original 20 on the platen 19 is again illuminated by the scanning lamps 33 at the optical system station C. The scan is synchronized with the movement of the injecting electrode to project a flowing image in registration with the first projection and moving at the same rate as is the surface 5 at the imaging zone.

The injecting electrode 1 then passes into the transfer station D. At station D is a transfer roller 40. A sheet of support material held in the supply tray 41 is lifted therefrom and is carried through a vacuum transport 42 to the transfer roller 40. It is gripped by a gripper mechanism 43 on the transfer roller 40 and rotated to the injecting electrode 1 passing at station D. Before the sheet 44 contacts the surface 5 of the injecting electrode 1 it is moistened with a liquid that will aid in transferring the particles of the suspension on the surface 5. The wetting is accomplished by a wetting bar 45 rotated in a pool of suitable wetting material held within a tank 46. The

transfer member 40 rotates the support material 44 in rolling contact with the surface 5 of the injecting electrode 1 under the influence of a suitable electric field causing the particles forming the image on the injecting electrode to be transferred to the support material. The support material is removed from the transfer member by picker fingers 47 and a release mechanism on the grippers. Next it is carried on a vacuum transport 48 to a fixing station E where it is heated or otherwise fixed to form a permanently bonded image on the support material which is then deposited in some suitable receptacle.

TRANSFER ASSEMBLY The transfer assembly is moved into and out of contact with the injecting electrode drum by the programmed operation of the main transfer cylinder 401 which, through a bolt 402, is fastened to the transfer assembly module frame 403. The module frames 403 and 404 are intimately fastened to the main machine frames and rest on the main machine rails 405 and 406 which position the module for proper contact with the injecting electrode drum. The main cylinder 401 is mounted through a clevis mount 407 to a crank arm 408. The crank arm is fixed to the positioning camshaft 409 which has an eccentric 410 mounted thereon for the moving of the transfer mechanism. Positioned over the eccentric 410 are two yokes 411 and 412 fastened to the main support blocks 413 and 414 through which the entire mechanism moves. The movement is limited by a setscrew stop 415 affording a positive stop against the fixed angle plate 418. The angle plates 416-419 each have a rail such as the rail 420 in the plate 417 and the rail 421 in the angle 419. These rails guide the mechanism in its movement back and forth into and out of interface with the injecting electrode cylinder path.

The transfer drum 40 itself is made of an aluminum tube 422 having a rubber sleeve 423 vulcanized thereto. The rubber sleeve is formed of an electrically conductive rubber. Around the outside of the rubber sleeve 423 is an electrically insulating material 424 forming the outer periphery of the transfer roller. form the frames to house the gripper box mechanism. The gripper box is formed of a phenolic housing 427 having a series of slot 428 formed therein. The slots are aligned with the lifter fingers 47 to ensure that they lift from the gripper housing box without interference during the removal operation of the transfer sheet. The gripper box is fastened into the roller by, for example, screws 429.

Inside the gripper box are a series of gripper fingers 430. They are a metal stamping and perform two separate services during the transport of a support material for transfer of an image. A first portion 431 holds the support material down against a steel finger 432 ensuring positive contact across the support material between the gripper finger and the housing box onto which the support material is pressed. The second portion of the gripper finger is the registration bar 433 which stops the sheet as it is fed into the gripper mechanism to prevent an overfeed of the leading edge of the support material. Each of the gripper mechanisms is fastened to a square shaft 434 by any means such as the screws 435 shown in the figures.

The transfer roller and the entire gripper mechanism rotate about the transfer roller shaft 436. At the start of the transfer function the roller is'positioned as shown in FIGS. 2-4. After gripping a piece of support material, the roller rotates in a counterclockwise direction (FIG. 4) with a surface velocity synchronized with the surface velocity of the injecting electrode cylinder 1. When the lead edge of the support material is pulled to a position around the periphery of the transfer roller coincident with the interface point of the prewet roll 45, the prewet roller is moved to interact with the transfer roll. The prewet roll 45 is a gravure-type roll made of hard metal. It is housed within an overflow tank 46 through suitable bearings in each end of the tank. The interaction of the prewet roller with the transfer roller is determined by the movement of the prewet follower arm 441 against the prewet roller cam 442 which is locked to the transfer roller sprocket drive 443. As the sprocket drive 443 rotates, it moves the prewet cam 442 with it. The prewet follower arm 441 follows the cam 442 causing the entire prewet mechanism to rotate about a pivot shaft 444 culminating in interfacing between the prewet roller 45 and the image support material on the transfer roller 40.

A prewet solution is maintained in the solution tank 445 which is supplied with solution through a fill tube inlet 446. Any overflow from the prewet tank 445 is caught in the overflow tank 46 and removed through a drain tube 447 for removal from the general area of the transfer roller assembly.

A transfer-aiding material is supplied to the transfer sheet by the prewet mechanism. A material such as the liquid carrier of the imaging suspension is excellent for aiding in more complete transfer. The carrier makes the particles on the injecting electrode 1 more mobile. This naturally aids in transferring them to the wetted support sheet S on the transfer roller 40.

In place of or in combination with the transfer aiding material, a fixing material can be applied by the prewet roll 45. This is accomplished by dissolving a binder material in the carrier liquid. Materials such as paraffin wax or other binders that come out of solution as the carrier liquid evaporates are suitable. 3-6 percent by weight of paraffin binder in the prewet liquid produces good fixing. The fixing material can be applied by the prewet roll 45 at the transfer station. It can include a binder material and a thermosolvent for the binder. The thermosolvent comprises a material that is solid at room temperature and melts above room temperature, thereby causing the binder-solvent layer to be tacky enabling the particles contacting it to become embedded therein. Typical materials that may be incorporated into the liquid carrier applied to the transfer sheet S by the prewet roller 45 may be found in copending application Ser. No. 808,921, filed in the names of L. Carreira, R. Rice and V. Mihajlov on Mar. l7, 1969 and entitled Imaging Process.

After interaction with the drum surface 5, the transfer roller 40 moves to the vicinity of the lifter fingers 47 for removal of the support material therefrom. At the support removal station shown in FIGS. 5 and 8, the gripper mechanism 43 operates in cooperation with the lifter fingers 47 to remove the sheet of support material from the transfer roller 40 and place the lead edge of the material on the transport 48. The lifter fingers 47 are securely and immovably fastened to the lifter finger bar shaft 450. Each of the fingers 47 are positioned to cooperate with slots 428 in the housing 427 of the gripper box. A puffer tube 543a extends an airblast under the lifted sheet to ensure proper removal from the transfer roller.

When the transfer roller moves to a predetermined position, the lifter cam 451 fixedly rotating with the main sprocket 443 driving the transfer roll causes the lifter follower arm 452 to rotate the lifter shaft 450. This moves the individual lifter fingers 47 down into the gripper housing 427 as shown in FIG. 9. The lifter follower arm 452 is securely fastened to the lifter shaft 450 by a clamp screw 453. As the cam 451 continues its rotation, the follower arm reaches the low dwell and the lifters snap into their up position carrying the lead edge of the support material with them.

During the operation of the lifter mechanism, the gripper fingers cooperate by opening after the lifter finger is in the position shown in FIG. 9. The fingers remain open until the lead edge of the support material has cleared the gripping mechanism. This event occurs twice during the cycle. Once in cooperation with the lifters for the release of the support material as shown here and once for the gripping of the support material when the transfer roller is approximately around from the lifter mechanism. The gripper fingers are controlled by a gripper cam 454 shown in its relative position with the lifter cam 451 in FIG. 11. The cam is actuated by either of two piston rods 455 and 456. The cam 454 is fixably attached to the square shaft 434 of the gripper mechanism at a rounded portion 457 thereof. The shaft is held in its down or gripping position by a holddown spring 458 which attached to a pin 459 formed as an integral part of the gripper cam 454. The cam rotates as part of the transfer roller and maintains the gripper mechanism in as gripping position until striking a piston rod 455 or 456 which is interposed into the path of the cam as the cam rotates with the transfer roller. The piston rods 455 and 456 are shaped to provide the proper bearing surface for the gripper cam 454 during contact therewith. The operation of the piston rods is best illustrated in FIG. 6 while the cooperation between the gripper mechanism and the lifter fingers is shown best'in FIGS. 8-10.

In FIG. 6 the piston rods 455 and 456 are actuated by air pressure entering through ingress ports 460 and 461 in the air box support block 413. The feeding of air through the ingress ports moves the pistons 462 or 462a extensions of which form the actuator rods 455 and 456 respectively. The piston is sealed with O-rings 463 and 463a to prevent inefficiency and escapement of air therefrom. Once activated, the actuator rod 455 protrudes into the path of the rotating cam 454 thus turning the cam as it moves over the actuator. The rotation causes the gripper fingers 431 to rise away from the steel finger 432 allowing the lead edge of a support material, sheet S, to be brought into or out of operable contact with the transfer roller.

The transfer roller is in effect an electrode which causes electrophoretic transfer of the particle image from the injecting electrode to the image support material carried by the transfer roller. In order to so transfer, an electrical bias of a charge opposite to that on the imaging electrodes is placed on the transfer roller. Although an image can be transferred without this bias applied to the transfer roller, the electrical bias enables more complete transfer of the image from the injecting electrode. To this end an electrical connection is made to the shaft 436 of the transfer roller by coupling a power source through an electrical conduit 488. A conductive bracket 489 connects the electrical source to electrical brushes 490 and 491 touching the shaft 436 of the transfer roller. The shaft 436 passes through an insulating air block housing wall 492 to the conductive end cap 493 of the transfer roller. This end cap in turn electrically contacts the metallic tubing 422 of the transfer roller. A field is generated through the conductive rubber outer sleeve 423 where, across the insulating coating 424, it provides a field with respect to the injecting electrode surface 5. This field is of such an electrical sign and potential as to aid in electrophoretically depositing the particles from the surface of the injecting electrode onto the image support material sheet S placed on the insulating coat ing 424 of the transfer roller.

After the support material is released from the transfer roller 40, the roller moves into contact with a roller cleaning brush mechanism generally referred to as 470. Instead of the brush cleaner discussed here, a cleaning mechanism such as that described in copending application Ser. No. 876,817, filed on Nov. 14, 1969, in the names of Christian 0. Abrew et al. and entitled Cleaning Apparatus could be used. The cleaning brush mechanism is enclosed in a shroud 471. The

mechanism cleans the surface 424 of the transfer roller with a brush 472 rotating in the direction indicated in FIG. 4. The upper portion of the bristles of the brush strike a flicker bar for removal of particles and droplets of liquid from the brush. The flicker bar 473 is mounted through a bracket 474 to a tie plate 475 within the shroud 471. Holes 476 are drilled in the tie plate to enable accumulated liquids to be drained therefrom. A hose is attached to the flange 477 in the shroud for vacuum removal of particles within the cleaning brush housing.

The brush 472 is rotated at approximately 1,000 rpm. by motor 478 operating through a drive pulley 479, a drive belt 480 and a driven pulley 481. The latter is fixably mounted on the brush shaft 482.

The brush tube 483 is mounted on spring steel supports 484 extending for the length of the tube and mounted on three hex blocks 485 which in turn are locked onto the brush shaft 482. The entire brush cleaning mechanism 470 is held within the transfer roller module by brackets 486 and 487.

FIXING STATION The support material to which an image has been transferred is moved into the fixing module at a guide plate 602 by the sheet transport 48. The oven-type module 603 is formed with an upper housing section 605 in communication with the lower housing section 607. An electric motor 609 circulates cool air through the fixer module 603 and is attached to the upper portion of the upper housing 605. The walls of the housings 605 and 607 are made from thick heat-insulating material for minimizing the heat transfer to other sections of the machine.

In operation an image-bearing sheet S of support material is moved into the lower housing 607 through a slot 611 therein. The sheet 5 is guided into the slot 611 by the plate 602 until the lead edge of the sheet is picked up by the conveyor system for the fixer module 603. The fixing occurs while the sheet S is transported through the lower fixer 607 by virtue of conduc tion and radiation during the sheet travel.

The conveying system for the fixer apparatus includes a relatively wide, single endless belt 613 of greater width than the sheet S but smaller than the vacuum platen 615 over which it moves. The belt is formed with many small apertures and is arranged to be driven around two rollers 617, 618 mounted transverse to the paper travel. The roller 617 is arranged at the input section of the fixer adjacent the entrance slot 611. The roller 617 is supported on a shaft 620 journaled in bearings mounted on each end of a U-shaped support device (not shown) secured to the outer walls of the housing 607. The other support roller 618 is supported for rotation upon a shaft 621 journaled at one end in a bearing secured to one end of a U-shaped support device (not shown) and, at the other end to a suitable drive system.

As the sheet S bearing a transferred image enters the housing 607 is comes in contact with the moving belt 613. A vacuum plenum 622 is arranged between the two runs of the belt and provides a reduced pressure upon the upper run of the belt for maintaining the sheet thereon. The apertures formed in the belt 613 ensures that there is a gradual flow of air from the space below the upper run of the belt toward the space between the runs of the belt. The vacuum platen 615 extends beyond the width of the belt 613 and has apertures beyond the belt width to cause a flow of air over the belt and into the vacuum plenum 622. This helps draw air into the fixer from the entrance slot 611 and the exit slot 624. In this manner all air and vapors within the fixer will be circulated through the fixer exhaust system 625.

As the sheet S moves along the belt 613, successive portions of the image are immediately influenced by the heated belt and the infrared radiation of the radiant heat lamps 626 which are of sufficient temperature as to cause the fixing material on the sheet S to become softened.

An inner chamber 628 is formed in the upper heating chamber 605. A rotatable impeller 629 is supported and driven by a drive shaft 630 arranged axially through the impeller and connected to a motor 609 adapted to impart rotation to the impeller 629. The impeller 629 is provided with vanes arranged in a pattern such that during energization of the motor 609, air is conveyed from within the internal space of the impeller outwardly into the upper heating chamber 628. This air is conveyed out of the chamber 628 through an opening 631 formed in a separation wall 632 separating the chamber 628 within the housing 605 from a lower chamber 634 within the housing 607.

As the air under pressure leaves the chamber 628 and enters the chamber 634, the pressure becomes slightly reduced since the chamber 634 is larger. This is effective to aid in directing air to the sheet S. This flow of air maintains the sheet S against the upper run of the belt 613. This flow pattern also ensures that air is pulled in from the ingress slot 61 1 and the egress slot 624 thus preventing vapor escape or movement of the sheet S off the belt 613.

The second heating stage that the image on the sheet experiences is in the form of radiated heat produced by parallelly arranged linear infrared heat lamps 626 aligned transverse to the sheet travel. The lamps are slightly above the upper run of the belt 613 and spaced along the length of the travel path of the sheet S over the belt. The heat lamps 626 may be of the quartz infrared type which are capable of producing relatively high heat quickly. They have a selfrefiecting upper envelope to reflect their radiation downward toward the belt and any sheet held to it.

Throughout the time during which the sheet S is within the chamber 634 of the lower heating housing 607 and during the operation of the lamps 626, the sheet is continually heated to some extent by conduction on the lower surface thereof. This heating by conduction is produced by quartz infrared lamps 635 mounted at the apex or focus line for reflectors 636 arranged to concentrate heat rays upon the belt 613 it it lower run as the same returns preparatory to the picking up of another sheet. The lamps 635 and the reflectors 636 are suitably mounted by a bracket (not shown) to the sides of the housing 607. This heating of the belt serves two functions. One is to present a heated conveying means which will be in intimate contact with a sheet S entering the fixer at a relatively cool temperature. This eliminates theprospect of the belt 613 becoming a heat sink for the heat being absorbed by sheet as it enters and comes into intimate contact with the belt. The other function is to preheat the sheet by conduction.

During continuous operation of the fixer module 603, the motor 609 remains continuously energized in order to continuously impart rotation to the impeller 629. Continuous movement of the belt 613 is maintained by a drive system (not shown) connected to the shaft 621. Air is continuously circulated throughout the entire module 603 by virtue of the rotation of the impeller 629. The air that is directed through the opening 631 is expanded as it enters the chamber 634. The air in then directed downwardly through and around the conveyor belt 613 and the rollers 617,618 and out of the interior space of the fixer by means of the outlet port 625. This movement of air creates the previously described vacuum conditions in the plenum chamber 622 and the vacuum, in conjunction with downward flow of air from the chamber 628, maintains each sheet in the fixer assembly against the conveyor belt 613. The term vacuum as used herein refers to a negative pressure, i.e., one less than atmospheric but not necessarily at absolute zero.

The sheet of support material may be a paper product coated with a thermal softenable material that is softened by the heat applied to it in the fixer. When the softenable coating is heated, the pigments forming the image move from their position above the surface of the softenable material into it and into the paper base which forms the sheet. When the sheet leaves the fixer, the softenable material cools and hardens forming a permanent protective coating over the pigment particles trapped therein.

When the sheet leaves the fixer unit it is picked up by a final transport which moves the sheet to a receiving tray for removal by a machine operator from the confines of the machine.

While this invention has been described with reference to the structures disclosed herein and while certain theories have been expressed to explain the experimentally obtainable results obtained, it is not confined to the details set forth; and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

What is claimed is:

1. Transfer apparatus including a transfer member;

means to fasten a support sheet on the surface of said member;

means to move said member along a path including a first position for interfacing with a substance for transfer to the sheet;

means to couple said member to an electrical source for electrophoretic attraction of the substance for transfer to the support sheet;

means to apply material to the support sheet on the member at a second position along a path of movement of the member prior to interface with the substance for transfer; and,

means to release the support sheet from the member at a third position along the path of movement thereof after transfer of the substance.

2. The apparatus of claim 1 wherein said means to apply material to the support sheet includes a material container;

applicator means in said container contacting the material and adapted to contact a support sheet on the transfer roller surface.

3. The apparatus of claim 1 wherein said means to move said member is adapted to rotate said member in interface with the substance for transfer in rolling contact.

4. The apparatus of claim 2 further including means to shift at least a portion of said applicator means into and out of interface with the support sheet, and

programmer means to activate and deactivate said means to shift at predetermined times during the movement of the transfer member.

5. The apparatus of claim 1 wherein said material includes a liquid.

6. The apparatus of claim 1 wherein the material applied to the support sheet is of the same matter as comprises a portion of substance for transfer.

7. The apparatus of claim 1 wherein the material includes a binder dissolved in a solvent.

8. The apparatus of claim 1 further including means to heat the support sheet after release from the member and means to transport the support sheet to the means to heat.

9. The apparatus of claim 8 wherein said means to heat include belt transport means to move a sheet through said means to heat;

a radiant heat source to supply radiant heat energy at the belt transport means, and

means to heat said belt transport means.

10. Apparatus of claim 1 further including means to clean the surface of the transfer member at a fourth position along the path of movement thereof after release of a support sheet from the member.

11. The apparatus of claim 10 wherein said means to clean further includes a brush;

means to rotate said brush;

a chamber housing said brush having an aperture for accepting said member and second aperture. and

pressure reduction means to remove contaminants from the chamber through the second aperture.

12. The apparatus of claim 11 further including a flicker bar operatively contacting the brush bristles for removing contaminants therefrom.

13. The apparatus of claim 1 wherein said means to fasten a support sheet includes gripper means;

actuator means to open and close said gripper means to accept and hold a support sheet;

control means to operate said means to open and close said gripper to accept a support sheet.

14. The apparatus-of claim 1 wherein said means to release the support sheet includes means to open said means to fasten;

lifter finger means to intercept the lead edge of a support sheet;

release actuator means to operate said means to open and said finger means in timed relation to release a sheet held by said means to fasten.

15. The apparatus of claim 14 including means to puff gases toward the lead edge of a support sheet at said means to release, said means to putt gases being activated by said release actuator means in timed relation to said lifter finger means.

16. The apparatus of claim 1 wherein said transfer member includes a shaft;

an electrically conductive core around said shaft;

a relatively electrically insulating sleeve intimately secured to said core,

a slot in said sleeve, and

a housing within said slot for maintaining said means to fasten a support sheet.

17. The apparatus of claim 16 including ment of said fingers.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3781517 *Mar 19, 1973Dec 25, 1973Xerox CorpFuser thermal protector
US3847119 *Mar 27, 1972Nov 12, 1974Xerox CorpTransfer roller assembly
US3894513 *Dec 6, 1972Jul 15, 1975Xerox CorpCopying machine with bead pickoff roller
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US8503912 *May 5, 2009Aug 6, 2013OCÚ PRINTING SYSTEMS GMBHDevice for preparing a recording medium for transfer printing toner images in an electro-phoretic printing system
US20110052274 *May 5, 2009Mar 3, 2011Michael PohltDevice for preparing a recording medium for transfer printing toner images in an electro-phoretic printing system
U.S. Classification399/77, 399/353, 15/1.51, 118/638, 118/223, 399/297
International ClassificationG03G15/20, G03G17/04, G03G17/00, G03G15/16
Cooperative ClassificationG03G17/04, G03G15/167, G03G15/2007
European ClassificationG03G17/04, G03G15/16F1, G03G15/20H1