US3893416A

US3893416A - Development and cleaning apparatus for reverse path machine

Info

Publication number: US3893416A
Application number: US429005A
Authority: US
Inventors: Roger H Eichorn
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1973-12-27
Filing date: 1973-12-27
Publication date: 1975-07-08
Anticipated expiration: 1992-07-08
Also published as: DE2454074A1; GB1476465A

Abstract

A member with a developable image thereon is passed through a development and cleaning station two times; once in one direction for development of the image with toner particles, and then in the opposite direction for cleaning the member of residual toner particles. A housing is mounted on the machine and is arranged to pivot to bring a development brush into its development operative position when the image containing member makes its first pass and is arranged to pivot to bring the development brush out of its operative position and bring a cleaning brush into its cleaning operative position when the image containing member makes the second pass.

Description

[451 Jul 8,1975

United States Patent [191 Eichorn, deceased 3,754,526 8/l973 8/637 3,806,355 4/1974 ll8/637 m5 m8 m Cu w n m 1 mm m I EE m a mm is rs PA [75] Roger H. Eichorn, deceased, late of Rochester, N.Y., by Lincoln First Bank of Rochester, executor [57] ABSTRACT A member with a developable ima through a development and cleani ge thereon is passed ng station two times; pment of the image [73] Assignee: Xerox Corporation, Stamford,

Conn.

[ Filed: 27, 1973 once in one direction for develo with toner particles, and then in t n A as h mm dn 3 m Sr 08 D." @w hm for cleaning the member of resid housing is mounted on the mac pivot to bring a development 21 Appl. No.: 429,005

118/637; ll7/l7.5; 355/15 [5]] Int. G03g 15/08 [52] U.S. Cl.

mwm m dhmm ecu Ev .w n mP ad r o m s ct -led .B g m 8 mm em .mm hb ment operative position when the ima of Search I l member makes first pass and is arran bring the development brush out of its operative posi- References Cited UNITED STATES PATENTS tion and bring a cleaning brush into its cleaning operataining member tive position when the image con r m F g .m m t D 3 s a a m i d h m C 1 ml e r t a k a m 755 H 6,55 855 I133 3,592,642 Kaupp........ 3,637,306 l/l972 Cooper 3,647,293 3/1972 Queener DEVELOPMENT AND CLEANING APPARATUS FOR REVERSE PATH MACHINE DESCRIPTION OF THE INVENTION It has been found that when a heat image is imparted on certain delayed tack adhesive members, the heated image when touched while in the supercooled state instantly turns to a solid state. This can be detrimental if touched by any object prior to developing the image.

When the delayed tack adhesive member is used in a system in which it passes through a development station twice, in opposite directions, and a cleaning brush is used, it could be detrimental to the image if the cleaning brush touches the image prior to development during the initial pass of the image through the development station. also, at times it is desirable that the development function be carried on only during one pass of the delayed tack adhesive member to prevent applying excess developer material to the member which may show up as background.

It is therefore an object of this invention to utilize a system wherein an image containing member passes through a development station twice, in opposite directions, and to engage the image containing member with a cleaning brush which engages an image containing member only after the image thereon has been developed and during the second pass of the image through the development station.

It is another object of this invention to provide a mechanism which effects development of an image only when an image containing member passes the same in one direction and which effects cleaning of the image containing member after the image has been developed and when the same passes the mechanism in the opposite direction.

Other objects of this invention will become apparent from the following description with reference to the drawings wherein:

FIG. 1 is a general schematic view of a copying apparatus during an imaging and developing function;

FIG. 2 is a partial view of the copying apparatus of FIG. 1 illustrating the position of a web after an image thereon has been developed; and

FIG. 3 is a view of the copying apparatus of FIG. 1 during cleaning of the web and transfer of a developed image to a copy medium.

Referring to FIG. 1, a web of heat sensitive material is fed from a supply spool 12 around idler rolls l4, l6, 18, and 22 to a take-up spool 24. The web 10 comprises a support with a heat sensitive coating. for example, the support may be paper or an organic film such as a polyester film, cellulose acetate or triacetate film coated with a delayed tack adhesive which is normally hard and non-tacky at room temperature, but which, upon being activated by heat to a tacky condition and subsequently cooled to room temperature, thereafter remains tacky for considerable periods of time varying from at least seconds to several days or more depending upon the particular composition involved. Such delayed tack coatings are well known and can be a mixture of discrete particles of resin such as indene resin or esterfied resin and discrete particles of crystalline plasticizer such as diphenyl phthalate or N- cyclohexyl paratoluene sulfonamide. The particles are bound together into the supporting film by a binder such as stryene-butadiene copolymer. Generally speaking, the crystalline plasticizer component of the mixture is in excess of the resin component.

The supply spool 12 and the take-up spool 24 are connected through separate slip clutches (not shown) to a reversible motor (not shown). The clutch connection for the supply spool 12 is such that the spool will be positively driven in a counterclockwise direction and slips to allow the spool to rotate in a clockwise direction. The clutch connection for the take-up spool 24 is such that the spool will be positively driven in a clockwise direction and slips to allow the spool to rotate in a counterclockwise direction.

A rotatable cylinder 26 having a highly reflective surface, which may be reversibly driven, is interposed between the idler rolls l6 and 18 and is so arranged that the web 10 is pressed against the idler rolls to form nips l7 and 19. An incandescent lamp 28 is located opposite the cylinder 26 and a reflector 30 is arranged to focus the rays of the lamp 28 onto the cylinder 26 between the idler rolls l6 and 18.

A developing station is provided which comprises a developer housing 32 having a bed of ferromagnetic toner particles 34 therein. The toner particles 34 comprise thermoplastic particles pigmented with carbon black or other radiation absorbing dyes or pigments, and mixed with iron oxide particles.

The developer housing 32 is pivotally mounted on a fulcrum 36.

Flanges

38 and 40 extend outwardly from the lateral ends of the housing 32 and each has a set screw 42 and 44, respectively, mounted therein. A pair of pads 46 and 48 are aligned with the set screws 42 and 44, respectively, against which their respective set screws abut. A coil spring 50 has one end anchored and its other end connected to a bracket 52 which in turn is secured to the housing 32. A solenoid 53 has a plunger 54 which is pivotally secured to an arm 56 connected to and extending outwardly from the housing 32. Upon actuation of the solenoid 53, the plunger 54 is moved downwardly to pivot the housing 32 in counter-clockwise direction about the fulcrum 36. A fur or synthetic fiber cleaning brush 58 and a well known magnetic brush 60 are rotatably mounted to the side walls of the housing 32. The upper wall 62 of the housing has a pair of

openings

64 and 66 through which a portion of the cleaning brush 58 and the magnetic brush 60 extend, respectively. The set screws 42 and 44 are adjusted to engage their respective pads so that upon rotation of the housing 32 by actuation of the solenoid, the magnetic brush 60 will be located in its operative position to present toner particles to an image on the web 10 and that upon clockwise rotation of the housing 32 under the influence of spring 50, cleaning brush 58 will be in its operative position to engage the web 10 to remove any toner particles adhering to background areas thereon. A stationary keeper plate 67 is provided opposite the developer housing 32 and keeps the web 10 in position to be engaged by the cleaning brush 58 when the brush is in its operative position.

A stack of copy sheets 68 is located on a paper tray 69. The stack of sheets are urged by a torsion spring 72 against a paper feed roll 74. The paper feed roll 74 drives the uppermost sheet of the stack along a guide 76 to a pair of nip rolls 78 which receive the leading edge of the copy sheet therein. At the proper time, the nip rolls 78 are actuated to drive the copy sheet to the nip 19. A storage recess 79 is provided in the guide 76 3 to allow the sheet to buckle until the nip rolls 78 are actuated.

An original inlet slot 80 is provided which opens adjacent the nip l7 and an original outlet slot 82 is provided adjacent the nip 19. A copy outlet opening 84 is provided which is also adjacent the nip 17. a microswitch 86 is provided in the original inlet opening 80 which, when actuated, serves to actuate a control mechanism (not shown) which performs the following operation:

Referring to FlG. 1, an original sheet 88 having an image thereon is fed into the inlet slot 80 actuating the switch 86 which sets in motion rotation of the cylinder 26 and the web supply roll 12 and the web take-up roll 24 and the magnetic brush 60 in the direction of the arrows. Also, actuation of this switch 86 effects illumination of the lamp 28 and actuation of the solenoid 53 to pull the plunger 54 downwards and thereby rotate the developer housing 32 in a counterclockwise direction until the set screw 42 engages the pad 46 bringing the magnetic brush 60 into an operative developing position. The leading edge of the original sheet 88 is fed into the nip 17 and is moved with the web past the lamp 28 and then the original separates from the web and is directed through the outlet opening 82. As the web and original pass the lamp 28, heat is absorbed by the image and transferred to the heat sensitive web 10 to form a tacky image corresponding to the image on the original sheet. As the web 10 and the original 88 pass around the cylinder 26, the sandwich is in tight engagement with the cylinder 26 assuring efficient heat transfer between the image and the heat sensitive layer. The web is transported past the magnetic brush 60 which presents toner particles to the web and develops the tacky image thereon. During development, the portion of the web passsing the magnetic brush takes support on the idler roll 20 which assures that the toner particles presented by the magnetic brush will engage the web. The control system employs a camming mechanism (not shown) which assures that the lamp 28 is illuminated for a sufficient time for the imaging process to be completed and then the lamp is turned off. Referring to FIG. 2, the camming mechanism also assures that a sufficient length of the web 10 corresponding to the length of the sheet to be copied passes at least the cleaning brush 68 with a portion of the leading edge of the developed image being wrapped on the take-up roll 24 as a single layer only to avoid any smudging of the developed image. to illustrate this, the leading edge of the developed image is indicated by reference numeral 90 and the trailing edge is indicated by reference numeral 92.

Referring to H6. 3, after the web 10 has stopped, the control mechanism includes means for deactuating the solenoid 53 whereby the spring 50 urges the toner reservoir 32 in a clockwise direction until the set screw 44 engages the pad 48 thereby bringing the magnetic brush 60 out of operative position and bringing the cleaning brush 58 into operative position to engage the web 10. At the same time, the rotation of the supply roll 12, take-up roll 24, and the rotation of the cylinder 26 is reversed, the cleaning brush actuated, and the paper feed roll 74 is actuated to move the leading edge of the uppermost sheet of the stack 68 into engagement with the nip rolls 78. The web 10 starts its reverse movement with the former trailing edge 92 now being the leading edge. The cleaning brush 58 engages the web 10 which takes its support against the keeper plate 67 during engagement thereby to brush off any toner particles which may be adhered to the background areas of the web. As the leading edge 92 of the image moves toward the nip 19, the nip rolls 78 are actuated at the proper time to move the copy sheet 68 to the nip 19 so that the leading edge of the copy sheet 68 will align with the leading edge 92 of the image just prior thereto. The lamp 28 is illuminated just prior to the leading edge 92 of the developed image and the copy sheet entering the nip 19. The aligned copy sheet and the heat sensitive web are forwarded past the lamp 28 whereby the rays therefrom heat the toner particles whereby a substantial portion thereof are transfixed (transfer and become fixed) to the copy sheet to provide a reproduction of the original image. This transfer occurs due to the pressure between the web 10 and the copy sheet 68 effected as they travel around the cylinder 26 and effected at the nip 17 combined with a corresponding proper temperature. As the copy sheet 68 emerges from the nip 17, the sheet separates from the web 10 and is directed out of the machine through the slot 84. The feed roll 74 is stopped after the copy sheet is discharged from the stack of sheets. After the trailing edge of the copy sheet 68 has emerged from the nip 17, the lamp 28 is turned off, the nip rolls 78 and cleaning brush 58 stopped. and the rotation of the web supply roll 12 and the take-up roll 24 is reversed to move the used portion of the web 10 to a point where the edge 92 of the last image formed on the web passes just beyond the nip 17 where the web is stopped in position for another copy to be made in the same manner as described above.

lf it should be disired to brush the tacky image with toner particles on each pass of the image through the development zone, then only the cleaning brush would be constructed to move in and out of engagement with the web with the magnetic brush always being in engagement with the web.

The control system and the components thereof for operating the machine in the manner described are all well known and well within the grasp of one having ordinary skill in the art and, therefore, have not been shown.

Since the imaging and developing function of the components of the machine is separate from the image transfer function, the intensity of the lamp 28 and the speed at which the web 10 travels in reverse can be changed from the intensity and speed for the imaging and developing function depending upon for what results the machine is designed.

While this machine has been described utilizing an automatic paper feeder, the machine also has utility where the copy sheet 68 is fed by hand into the machine. In this instance, a pair of nip rolls may be located in the slot 82 which rotate in one direction to withdraw the original from the machine and rotate in the opposite direction at the proper time to pull a copy sheet inserted into the slot 82 to meet the leading edge 92 of the web just prior to the nip 19 for the tranfer and fixing of the toner powder image from the web to the copy sheet.

Rather than transfer the developed image to a copy paper, the developed image may be fused onto the heat sensitive web 10. This may be desired when a series of copies are needed in a specified sequence. In this respect, the surface of the cylinder 28 which will be contacted by the toner particles during the fixing or fusing step must comprise a material to which melted toner particles will not stick. Alternatively, a stack of release sheets could be placed on the paper tray 69 and fed past the lamp 28 in contact with the developed image. In this case, the release sheet will be of a material to which the toner particles will not stick.

It should be further realized that the concept of this invention is also applicable to developing image bearing members in sheet form rather than in web form as long as means are provided to reverse the path of travel of the sheet to pass through the development and cleaning station in opposite directions.

What is claimed is:

1. A copying apparatus comprising: a development station, a member having a developable image thereon, means for moving said image containing member in opposite directions through said development station, said development station comprising a developer housing having toner particles therein, development means located to present toner particles from said housing to the image in a developing operating position, and cleaning means for cleaning toner particles from said image member in a cleaning operating position, means for moving said development means into developing operation position to be in such position when said image member is moved in one direction therepast, and

means for moving said cleaning member into cleaning operating position to be in such position when said image member is moved in the opposite direction therepast.

2. The structure as recited in claim I, wherein said development means and said cleaning means are carried by said developer housing, a support member, means pivotably connecting said developer housing to said support member, said development means and said cleaning means being located on opposite sides of said pivotal connection, said means for moving said development means and said cleaning means into their operating positions being operably connected to said housing for pivoting the same.

3. The structure as recited in claim 2, wherein said developing means is a magnetic brush and said toner particles are ferromagnetic.

4. The structure as recited in claim 3, wherein said cleaning means comprises fibers in the form of a brush.

5. the structure as recited in claim 2 further comprising adjustable stop means carried by said developer housing and said support member so located to limit the pivotal movement of said developer housing in either direction.

6. The structure as recited in claim 5, wherein said developing means is a magnetic brush and said toner particles are ferromagnetic.

7. The structure as recited in claim 6, wherein said cleaning means comprises brush fibers in the form of a brush.

8. In a copier having a substrate for carrying latent images, applicator means for applying toner to said substrate to develop said images, and cleaning means for removing excess toner from said substrate; the improvement comprising the combination of means for moving said substrate in first and second opposite directions along a predetermined path, a housing supporting said applicator means and said cleaning means in spaced apart relationship adjacent said path, and means pivotally mounting said housing for rotation about an axis disposed between said applicator means and said cleaning means; said axis being substantially normal to said path, thereby enabling said applicator means and said cleaning means to be selectively brought into operating relationship with said substrate by rotating said housing in opposite directions about said axis.

9. The improvement of claim 8 further including means for rotating said housing about said axis in one direction when said substrate is moving in said first direction and in the opposite direction when said substrate is moving in said second direction, whereby said applicator means and said cleaning means are selectively brought into operating relationship with said substrate in response to the direction of movement of said substrate.

10. The improvement of claim 9 wherein said toner is ferromagnetic; and said applicator means comprises a magnetic brush, and means for rotating said magnetic brush.

1]. The improvement of claim 10 wherein said cleaning means comprises a cleaning brush, and means for rotating said cleaning brush.

I i i =0

Claims

1. A copying apparatus comprising: a development station, a member having a developable image thereon, means for moving said image containing member in opposite directions through said development station, said development station comprising a developer housing having toner particles therein, development means located to present toner particles from said housing to the image in a developing operating position, and cleaning mEans for cleaning toner particles from said image member in a cleaning operating position, means for moving said development means into developing operation position to be in such position when said image member is moved in one direction therepast, and means for moving said cleaning member into cleaning operating position to be in such position when said image member is moved in the opposite direction therepast.

2. The structure as recited in claim 1, wherein said development means and said cleaning means are carried by said developer housing, a support member, means pivotably connecting said developer housing to said support member, said development means and said cleaning means being located on opposite sides of said pivotal connection, said means for moving said development means and said cleaning means into their operating positions being operably connected to said housing for pivoting the same.

11. The improvement of claim 10 wherein said cleaning means comprises a cleaning brush, and means for rotating said cleaning brush.