US3337891A

US3337891A - Plate cleaning and transporting apparatus

Info

Publication number: US3337891A
Application number: US422325A
Authority: US
Inventors: Thomas C Murray; Fritz B Laessker
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1964-12-30
Filing date: 1964-12-30
Publication date: 1967-08-29
Anticipated expiration: 1984-08-29

Description

29, 1967 T. c. MURRAY ETAL I 3,337,891

PLATE CLEANING AND TRANSPORTING APPARATUS Filed Dec. 30, 1964 4 Sheets-Sheet l INVENTORS THOMAS C. MURRAY FRITZ B. LAESSKER ATTOR 5V8 29, 1957 T. c. MURRAY ETAL 3,337,891

PLATE CLEANING AND TRANSPORTING APPARATUS 4 Sheets-Sheet 2 Filed Dec. 30, 1964 INVENTORS THOMAS C. MURRAY FRIT B. AESSKER BY xii g 5 ATTOR/V VS 9, 1967 T. c. MURRAY ET'AL 3,337,891

PLATE CLEANING AND TRANSPORTING APPARATUS Filed Dec. 30, 1964 4 Sheets-Sheet 3 FIG. 3

4 INVENTOR5 THOMAS C. MURRAY BY FRITZ B. LAESSKER Aug. 29, 1967 T. c. MURRAY ETAL 3,337,891

PLATE CLEANING AND THANSPORTING APPARATUS Filed Dec. 30, 1964 4 Sheets-Sheet 4 INVENTORS F/G. 5 THOMAS c. MURRAY BY FRITZ a. LAESSKER United States Patent O 3,337,891 PLATE CLEANING AND TRANSPORTING APPARATUS Thomas C. Murray, Rochester, and Fritz B. Laessker,

Fairport, N.Y., assignors to Xerox Corporation, Rochester, N.Y., a corporation of New York Filed Dec. 30, 1964, Ser. No. 422,325 4 Claims. (Cl. 15-102) This invention relates to a xerographic plate cleaning apparatus and more specifically to apparatus for transporting a xerographic plate past a cleaning roll.

In the process of xerography, a metal plate containing a photoconductive surface is charged, exposed and developed. That is, a uniform electrostatic charge is placed on the plate surface. The plate is then exposed to a light image of copy to be reproduced, resulting in a latent electrostatic image of the original copy on the plate surface. The electrostatic image is developed by covering the plate surface with a finely divided powder. The powder adheres to the plate in the areas containing electrostatic charge, thus producing a powder image of the original copy. The powder image is transferred to a support material surface and is bonded thereto. A quantity of residual powder adheres to the plate surface after the image is transferred to the support material surface and must be removed before the xerographic plate can be used to develop a new image. Suitable apparatus for charging and exposing the xerographic plate and for developing the powder image thereon is fully described in copending application Ser. No. 227,340, filed Oct. 1, 1962 in the name of Thomas C. Murray et al.

One cleaning unit is shown in US. Patent No. 3,149,- 356, issued Sept. 22, 1964, in the name of Thomas C. Murray et al., which shows a xerographic cleaning unit of which this is an improvement. The xerographic plate has a coating of selenium or other photoconductive material thereon. In the process of cleaning the'plate, no excess pressure should be applied thereto in order to avoid any damage to the plate. In the aforementioned plate cleaner, the web cleaning'roll can only be adjusted relative to the drive roll. This allowed variation of the web pressure with respect to the drive roll, but this adjustment also changed the pressure between the plate and the drive roll. Due to sensitivity of the xerographic plate, it is desirable to be able to vary the drive pressure without varying the pressure between the plate and the web cleaning roll in order to avoid any damage to the plate. Also, the pressure between the web cleaning roll and the plate should be capable of adjustment without changing the drive pressure.

It is therefore the principal object of this invention to improve xerographic plate transporting apparatus to allow adjustment of the drive roll without changing the amount of pressure between the xerographic plate and the web cleaning roll.

A further object of this invention is to improve xerographic plate transporting apparatus to allow adjustment of the pressure between the drive roll and the plate while the web pressure remains constant.

Still another object of the present invention is to improve xerographic plate transport apparatus wherein idler rollers adjacent the end of the web rolls serve to increase the force between the back of the xerographic plate and the drive roll without increasing Web pressure.

These and other objects of the present invention are attained by apparatus for independently adjusting the pressure between the xerographic plate and drive roll.

For a better understanding of the invention, as well as of the objects and further features thereof, reference is had to the following detailed description of the invention Patented Aug. 29, 1967 to be read in connection with the ings, wherein:

FIGURE 1 is a perspective view of a xerographic transfer and cleaning unit incorporating the present invention;

FIGURE 2 is a schematic representation of the web travel of the web cleaning device;

FIGURE 3 is an enlarged partial front view of one embodiment of the web cleaning assembly with parts broken away to show internal construction of the cleaning unit shown in FIGURE 1;

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

FIGURE 5 is a side view of the unit shown in FIGURE 1;

FIGURE 6 is an enlarged partial front sectional View of another embodiment of the present invention with parts broken away to show internal construction.

Referring now to FIGURE 1, there is a xerographic transfer and cleaning unit including a base 1.

The xerographic plate 6 consists of a photoconductive surface 9, such as selenium, on a conductive backing member 10. The photoconductive surface 9 does not completely cover the plate member 10, thus leaving a border or edge 11 around the outer periphery of the plate. When the plate 6 is placed in the transfer unit, there is a powder image on the photoconductive surface 9 which is to be transferred to a sheet of paper or support material. Proper alignment of the support material with respect to the powder image is important for proper registration of the final transferred image onto the support material. To ensure that the plate 6 does not move during the transfer operation, plate clamps 12 and 13 are provided at the sides of the plate 6. The transfer of the xerographic powder image from the plate surface to the support material is effected by means of an electrostatic transfer device indicated as 15. The transfer unit is moved across the base by means of tracks 17.

After transfer of the powder image from the xerographic plate 6 to the support material, the support material is removed from the plate 6 and transferred to a suitable fusing device, as for example, the type disclosed in copending application, Ser. No. 227,472, filed Oct. 1, 1962 in the name of Thomas C. Murray et al.

After a xerographic plate has been used to produce a powder image and that image has been transferred to a support material, there is a certain quantity of residual powder which adheres to the plate surface. It is necessary to completely remove the residual powder prior to reusing the plate. The residual powder is held on the plate by an electrostatic charge; therefore, prior to attempting to remove the powder from the plate surface, an opposite charge is applied to the plate surface. This is accomplished by a stationary electrostatic discharge device (not shown) which negatively charges the plate. The xerographic plate is moved manually from the transfer apparatus to the web cleaner 20. As the plate 6 moves toward the web cleaner 20, it actuates microswitch initiating operation of the cleaning apparatus by means of a motor MOT-1. The motor MOT1 will start the movement of main drive pulley 98, to be described below. The plate 6 is forced between drive roll 111 and idler rolls 201 propelling the plate forward through the web cleaner 20. A disposable fibrous web of material 86 is then forced into sliding contact with the plate surface and absorbs residual powder loosened therefrom by the application of the electrostatic charge. Although only the lefthand side of the cleaning apparatus is shown in FIGURE 3, it is understood that a similar right-hand side exists. The web cleaning apparatus, as shown in FIGURE 3, consists of a pair of support frame members 87 secured accompanying drawxerographic cleaning 3 to main frame 1 in a position to receive plate 6 as it is urged forward. Mounted internally of the support frame 87 is a bearing plate 88 spaced from the frames 87 by spacer 89 and pivotally secured thereto by fasteners 90. Mounted on the bearing plate 88 is a web supply shaft 91, web cleaning shaft 92, and a web take-up shaft 93 rotatably journaled in bearings 94, 95 and 96, respectively.

An adjustment bar 84 is secured to both frame members 87 and contains a pair of set screws 85 that bear against the bearing plates 88. Movement of set screws 85 produces a pivoting movement of the bearing plates 88 and an adjustment of the space between a web cleaning roll 114 on shaft 92 and a drive roll 111, thus regulating the pressure applied to the xerographic plate.

Power to the web cleaner is transmitted from a motor MOT1 through drive belt 97 to main pulley 98 connected to drive shaft 99. Drive shaft 99 is appropriately journaled in the support frame 87 and drives the plate drive roll 111. The opposite end of drive shaft 99 is journaled in the opposite support frame 87, shown in FIGURE 5. A pinion 101, mounted on shaft 99, drives a gear 102 to supply power to a power transmission shaft 103. Shaft 103 is journaled in the support frames 87 and, at the opposite end from the gear 102, contains a pinion 104 which transmits power to a series of gears 105 and pinions 106 to produce a speed reduction in a gear 107 mounted on the web cleaning shaft 92. The speed of the shaft 99 and drive roll 111 is approximately 20 times as fast as fast as the speed of the web cleaning shaft 92, thus producing a sliding motion of the plate past the web, and continually exposing clean web to the plate surface.

The cleaning shaft 92 contains a resilient roller around which the web 86 passes, and is pressed into intimate contact with the surface of the Xerographic plate 6. On the opposite end of the web cleaning shaft 92 is a pulley 108 and a belt 109 for transmitting power to a pulley 110 mounted on web take-up shaft 93. Shaft 93 accumulates used web material after it has been in contact with the surface of the Xerographic plate 6. Clean web material is supplied from a roll 113 on supply roll shaft 91. The drive roll 111 consists of resilient material mounted on shaft 99 and is kept free of lint and dirt by a brush 124 supported by the frame members 87.

As shown in FIGURE 3, adjacent each end of the web cleaning roll 114 there is an idler pulley 201 attached to a hollow shaft 202 which is journaled for rotation in -a bearing 203 in bracket 204 which is adjustably mounted on support frame 87. The bracket 204 is pivotally adjustable about pivot pin 205 by means of adjusting screw 206. One end of screw 206 is mounted in bracket 204 while the other end is slidable in slot of frame member 87. When the screw 206 is loosened, the bracket 204 and the idler roll 201 may then be adjusted relative to drive I011 111. The brackets 204 are connected by means of a bar 210, shown in FIGURES 1 and 4. Thus, when the screws 206 are loosened, both brackets 204 may be adjusted equally due to the presence of bar 210 so that idler pressure roll 201 will exert the same pressure on both borders of the Xerogra-phic plate 6. By means of this construction, it is possible to adjust the pressure between the drive roll 111 and the idler pressure roll 201 independently of the web roll 114. It is also possible to adjust the pressure of the web roll 114 with respect to the drive roll 111 by means of adjustment bar 84 without adjusting the idler pressure roll 201. It is, of course, necessary to make the shaft 202 larger than shaft 92 in order to allow for relative adjustment of the two rolls.

There is seen schematically in FIGURE 2, the web 86 supplied from a roll 113 on a shaft 91 which passes around a rubber or resilient cleaning roll 114 on shaft 92 and contact xerographic plate 6, passes behind a web guide 115 and is wound up on a take-up roll 116 on shaft 93. To permit replacement of the web supply roll 113 and removal of take-up roll 116, the bearings 96 and 94 are constructed with cut-out portions 117. A lock clip 118 is joined to the bearing plate 88 to retain the shafts 91 and 93 in the bearings 94 and 96, respectively. The lock clip 118 contains a vertical slot 119 and is held in bearing plate 88 by studs 120 which pass through slots 119. The lock clip 118 is movable in a vertical direction by lifting upward on -a lever 121. The upward movement of the lever 121 removes the locking arm 122 from the cut-out portions 117 of bearings 94 and 96, freeing'the shafts 91 and 93.

As the plate 6 passes over microswitch 75, the microswitch is held in a depressed position but as the trailing edge of the plate passes over the microswitch, the switch is released turning off the power to drive rolls. The switch 75 is positioned and adjusted to cut off the drive motor MOT1 when the margin of the plate 6 is between rolls 111 and 114. The plate is then stationary and supported essentially by the border 11, between the web cleaning roll 114 and the plate support roll 111. The forward or leading edge of the plate is supported upon a bracket 123 extending outward from the support frame 87. The plate will remain in this position supported by the bracket 123 and the web cleaning roll 114 and the plate support roll 111 until such time as it is picked up by an operator.

FIGURE 6 shows an alternate embodiment of the present invention similar to the apparatus shown in FIGURE 3. The idler pressure roll-250 is mounted on shaft 251. The idler pressure roll shaft 251 is mounted in a cantilever manner on bracket 252 which is mounted and adjustable in the same manner as bracket 204 described with respect to FIGURE 3.

By this construction it is possible to adjust the pressure between the drive roll 111 and the idler pressure rolls 250 independently of the web roller 114. It is also possible to adjust the pressure of the web roll 11.4 with respect to the drive roll 111 without adjusting the idler pressure roll 250.

While the invention has been described with reference to structures disclosed herein 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 improvement or the scope of the following claims.

What is claimed is:

-1. A device for transporting a xerographic plate past a cleaning web comprising:

a pair of support frame members;

a pair of bearing plates pivotally connected to said frame members;

a drive roll journaled for rotation in said frame members to drive a Xerographic plate between the frame members;

a web roll journaled for rotation in the bearing plates above the drive roll to be in contact with a xerographic plate being driven by said drive roll;

means to rotate said web roll in a direction so that the surface of the web roll moves in a direction opposite to the movement of a xero graphic plate;

adjusting means to pivot said bearing plates relative to said frame members to change the spacing between the web roll and the drive roll;

means to rotate the drive roll to produce movement of a xerographic plate;

a pair of brackets adjustably supported from each frame member;

a rotatable idler pressure roller mounted on each bracket adjacent each end of the web roll in contact with the surface of a xerographic plate being moved by the drive roll, said bracket being adjustable to force the idler pressure roller into surface contact with a xerographic plate to hold the plate against the drive roll with a pressure greater than that extended by the web roll.

2. A device for transporting a xerographic plate past a cleaning roll comprising:

a pair of side frames;

a cleaning roll mounted between the side frames in a position to press against the surface of a xerographic plate being moved between the side frames;

a drive roll journalled in the side frames below the cleaning roll to drive a xerographic plate past the cleaning roll;

drive means to rotate the drive roll;

means to rotate the cleaning roll to provide relative surface movement between the cleaning roll and the xerographic plate;

means to adjust the cleaning roll position to vary the pressure on a xerographic plate being moved past the cleaning roll; and,

idler rollers mounted on the side frames juxtaposed the cleaning roll to force a Xerographic plate against the drive roll independently of the pressure on the plate due to the cleaning roll, said idler rollers being adjustable to vary the pressure on a xerographie plate being driven by the drive roll.

3. A device for transporting a xerographic plate past a cleaning roll comprising:

a pair of side frames;

-a cleaning roll mounted between the side frames in a position to press against the surface of a xerographic plate being moved between the side frames;

a drive roll journaled in the side frames below the cleaning roll to drive a xerographic plate past the cleaning roll;

drive means to rotate the drive roll;

idler rolls mounted on the side frames juxtaposed the cleaning roll and concentric therewith to force a xero- 2,335,196 11/1943 Pecsok CHARLES A. WILLMUTH, Primary Examiner. L. G. MACHLIN, Assistant Examiner.

graphic plate against the drive roll independently of the pressure on the plate due to the cleaning roll; said idler rolls being adjustable to vary the pressure on a Xerographic plate being driven by the drive roll. 4. A device for transporting a xerographic plate past a cleaning roll comprising:

idler rollers mounted on shafts journaled in the side frames to force a xerographic plate against the drive roll, independently of the pressure on the plate due to the cleaning roll, said idler rollers being adjustable "to vary the pressure on a xerographic plate being driven by the drive roll,

said idler roller shafts being positioned juxtaposed to the cleaning roll shaft.

References Cited UNITED STATES PATENTS 684,282 10/1901 Masson et al 118-249 X 29-81

Claims

1. A DEVICE FOR TRANSPORTING A XEROGRAPHIC PLATE PAST A CLEANING WEB COMPRISING: A PAIR OF SUPPORT FRAME MEMBERS; A PAIR OF BEARING PLATES PIVOTALLY CONNECTED TO SAID FRAME MEMBERS; A DRIVE ROLL JOURNALED FOR ROTATION IN SAID FRAME MEMBERS TO DRIVE A XEROGRAPHIC PLATE BETWEEN THE FRAME MEMBERS; A WEB ROLL JOURNALED FOR ROTATION IN THE BEARING PLATES ABOVE THE DRIVE ROLL TO BE IN CONTACT WITH A ZEROGRAPHIC PLATE BEING DRIVEN BY SAID DRIVE ROLL; MEANS TO ROTATE SAID WEB ROLL IN A DIRECTION SO THAT THE SURFACE OF THE WEB ROLL MOVES IN A DIRECTION OPPOSITE TO THE MOVEMENT OF A XEROGRAPHIC PLATE; ADJUSTING MEANS TO PIVOT SAID BEARING PLATES RELATIVE TO SAID FRAME MEMBERS TO CHANGE THE SPACING BETWEEN THE WEB ROLL AND THE DRIVE ROLL; MEANS TO ROTATE THE DRIVE ROLL TO PRODUCE MOVEMENT OF A XEROGRAPHIC PLATE; A PAIR OF BRACKETS ADJUSTABLY SUPPORTED FROM EASCH FRAME MEMBER; A ROTATABLE IDLER PRESSURE ROLLER MOUNTED ON EACH BRACKET ADJACENT EACH END OF THE WEB ROLL IN CONTACT WITH THE SURFACE OF A XEROGRAPHIC PLATE BEING MOVED BY THE DRIVE ROLL, SAID BRACKET BEING ADUSTABLE TO FORCE THE IDLER PRESSURE ROLLER INTO SURFACE CONTACT WITH A XEROGRAPHIC PLATE TO HOLD THE PLATE AGAINST THE DRIVE ROLL WITH A PRESSURE TOGETHER THAN THAT EXTENDED BY THE WEB ROLL.