JPH04212983A - Cleaning device for eletrostatic-photograph-image forming apparatus - Google Patents

Abstract

PURPOSE: To enhance the blade type cleaning effect of the cleaning device of an electrostatic photographic image forming device and to reduce the damage of the blade thereof. CONSTITUTION: A pair of pre-cleaning blades 94 and 96 is arranged on the upstream side of the blade 90 of the cleaning device and the edges thereof are formed so as to be rugged saw-tooth-shape. Besides, the saw-tooth-shaped blade edges are deviated in a direction that they cross a photoreceptor so as to compensate each other. As the result, toner left on the photoreceptor is largely stirred by a pair of saw-tooth-shaped blades 94 and 96. Besides, the blade 90 is lubricated and prevented from being destroyed while the cleaning efficiency thereof is enhanced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electrostatographic imaging apparatus, and more particularly to a cleaning apparatus for an electrostatographic imaging apparatus having a front cleaning blade.

0002

BACKGROUND OF THE INVENTION In electrophotography, such as xerography, a charge retentive surface is electrostatically charged in accordance with a light pattern of an image of an original to be reproduced and is exposed to retain a charge in accordance with the light pattern. Discharge the surface selectively. The resulting pattern of charged and discharged areas on the surface forms an electrostatic charge pattern (an electrostatic latent image) that matches the image of the document. This latent image is developed by contacting the latent image with a fine electrostatically attractable powder called toner. The toner is retained on the image area by the electrostatic charge on the charge retentive surface. Therefore, the toner image is formed in conformity with the optical image of the original being copied. The toner image can then be transferred to a support (eg, paper) and the toner image fused to the paper to permanently record the image to be reproduced on the support. After development, excess toner remaining on the charge retentive surface is cleaned from the charge retentive surface. This process is well known and is used in devices that print from originals that are generated or stored by electrostatic charges that can be image-shaped discharged in various ways through optical lenses and charged surfaces that make copies from originals. Useful. Ion projection devices in which a charge is deposited imagewise onto a charge retentive surface similarly operate by this process.

0003

During the transfer process, most of the toner forming the image is transferred to the paper, but some amount of toner always remains on the charge retentive surface and is held by electrostatic force or mechanical force. Additionally, paper fibers, kaolin and other debris have a tendency to be attracted onto the charge retentive surface. For optimal operation, it is essential to thoroughly clean and remove any residual toner on the charge retentive surface. Cleaning with a blade is simple and inexpensive compared to the various fiber or magnetic brush cleaners well known in xerographic technology, and removes residual toner and debris (hereinafter referred to as "toner"). In a typical application, a elastomeric blade member of relatively thin thickness is provided, and the charge retention in the direction transverse to the direction of relative movement is highly desirable. The charge retentive surface is supported adjacent to the charge retentive surface in substantially sealed contact with the charge retentive surface, and the edges of the blade scrape or wipe toner from the charge retentive surface, including, of course, blades made of metal or other plastic materials. After ejection of the toner from the charge retentive surface, the ejected toner is carried away from the area of the cleaning blade by a toner transport device or by gravity.

Solid toner areas create stress conditions in cleaning equipment. Disturbing the toner prior to cleaning has been performed as an additional task on cleaning devices. An example of such a device is illustrated in U.S. Pat. No. 3,617,123, which uses a vibrating brush to improve cleaning by the developer device. This vibrating brush
The photoreceptor is located upstream of the location where it enters an apparatus that performs a combination of development and cleaning. This brush is
The brush fibers are mounted longitudinally along the surface of the photoreceptor so that they are in light contact with the surface to be cleaned, and are oscillated laterally across the surface of the drum. The brush mechanically repositions or disturbs any accumulated residual toner and spreads the toner uniformly across the imaging surface to interrupt mechanical adhesion of the toner to the photoreceptor in the image. do. however,
After long-term use, toner soaks into the bristles of the brush, resulting in the brush becoming ineffective for its intended purpose. U.S. Pat. No. 4,627,717 similarly discloses a magnetic structure adjacent to an imaging surface and a magnetic cleaning brush that generates a pulsating magnetic field that acts to agitate and disturb toner in the magnetic structure. Are listed. Also, September/October 1977
Xerox Dischsure J issued in March
Editorial text of “Photoconductor Scrubber” by J.
Foaming as a Disturber -
A rubber roller is shown.

[0005] The provision of redundant cleaning equipment also provides certain cleaning benefits. No cleaning device is completely effective, and the performance of the cleaning device can be improved by providing backup or redundant devices. U.S. Reissue Pat. No. 30,924 shows a series of cleaning blades along the process direction of a copier, with one cleaning blade supporting another cleaning blade. It has become. A problem to be noted in such devices is that an insufficient amount of lubricant-carrying toner passes through the upstream blade to lubricate the downstream blade. This can lead to blade damage due to increased friction.

[0006]

SUMMARY OF THE INVENTION In accordance with the present invention, in an electrostatographic imaging apparatus in which residual toner remains on the imaging surface after the imaging step is completed, a blade A device is provided that provides a pair of complementary textured serrated blades on the upstream side of the cleaning device.

According to the present invention, the cleaning device disposed at the 12 o'clock position with respect to the image forming surface to be cleaned includes a 1
A pair of complementary serrated blades are positioned slightly upstream from the main cleaning device. In this device, the serrated blade acts as an image disruptor for the main cleaning device to mechanically break the strong adhesion between the toner and the imaging surface. The primary cleaning device is preferably a blade cleaning device in sealing contact with the imaging surface.

[0008] Concave and convex serrated blades are an important addition to the main cleaning system by providing image disturbance and/or extra cleaning using an inexpensive structure with little negative impact on the main cleaning system. give advantages.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the invention will become apparent from the following description, which, taken in conjunction with the accompanying drawings, serves to illustrate one preferred embodiment of the invention.

The invention will now be described with reference to the accompanying drawings, which are for the purpose of illustrating a preferred embodiment of the invention and are not intended to limit the invention. The various processing stations used in the electrostatographic copying machine illustrated in FIG. 1 will now be briefly described. The various processing elements are also advantageously used in electrostatographic printing from electronically stored originals and, with suitable modifications, ion projection which fixes ions in the form of an image onto a charge retentive surface. It will certainly be understood that it is also used in equipment.

The copying machine in which the present invention is advantageously employed employs a photoreceptor belt 10 having a photoconductive surface 11. Belt 10 moves in the direction of arrow 12 to sequentially advance successive sections of the belt through various processing stations disposed about its path of travel.

Belt 10 is advanced around stripping roller 14 , tension roller 16 and drive roller 20 . The drive roller 20 is connected to a motor 21 by suitable means, for example a drive belt.

The belt 10 connects the tension roller 16 to the belt 1
It is maintained taut by a pair of springs (not shown) that resiliently bias against zero with a desired spring force. Peel roller 14 and tension roller 16 are both rotatably mounted. These rollers are attached to the belt 10
is an idler roller that rotates freely when moving in the direction of arrow 12.

Still referring to FIG. 1, a portion of belt 10 first passes through charging station A. At charging station A, corona generating device 22 charges photoreceptor belt 10 to a relatively high and substantially uniform positive or negative potential.

At exposure station B, an original is placed face down on a transparent platen 30 for illumination by a flash lamp 32. The light beam reflected from the original document is reflected through lens 33 and projected onto the charged portion of photoreceptor belt 10, thereby selectively dissipating the charge on the charged portion. As a result, an electrostatic latent image is recorded on the belt corresponding to the informational areas contained in the document. Alternatively, a laser can be used to discharge the photoreceptor in an image shape according to electronic information.

Belt 10 then advances the electrostatic latent image to development station C. Belt 10 then advances the electrostatic latent image to development station C. At development station C, one of at least two developer housings 34 and 36 is brought into contact with belt 10 for the purpose of developing the electrostatic latent image. The housings 34 and 36 have corresponding cams 3 selectively driven by the motor 21.
8 and 40 for movement into and out of the development position. Each developer housing 34 and 36 supports a development device, such as magnetic brush rolls 42 and 44. magnetic brush roll 4
2 and 44 constitute a rotating magnetic member that advances the developer mixture (ie, carrier and toner) into contact with the electrostatic latent image. The electrostatic latent image attracts toner particles from the carrier, thereby forming an image of toner powder on photoreceptor belt 10. If dual color developer material is not required, the second developer housing can be omitted.

Belt 10 then advances the developed latent image to transfer station D. Transfer station D
In , a sheet of support material, e.g., copy paper, is advanced into contact with the developed latent image on belt 10 . Corona generating device 46 charges the copy paper to the proper potential, thereby adhering the copy paper to photoreceptor belt 10 and attracting the toner powder image from photoreceptor belt 10 to the copy paper. After transfer, corona generator 48 nullifies the charge on the copy paper and peels the copy paper from belt 10, after which the copy paper is stripped from belt 10 by peel roller 14.

Support, ie, sheet of support material 49
is advanced from supply tray 50 to transfer station D. Sheets 49 are fed by sheet feeder 52 from feed tray 50 and advanced along conveyor 56 to transfer station D. After transfer, sheet 49 continues to move in the direction of arrow 60 to fusing station E.

Fusing station E includes a fusing assembly designated generally at 70. Fuser assembly 70 permanently fuses the transferred toner powder image to the sheet. Fuser assembly 70 preferably includes a heated fuser roller 72 brought into pressure engagement with a backup roller 74 to contact the toner powder image with the fuser roller. In this manner, the toner powder image is permanently affixed to the sheet, and such sheet is sent to a delivery device 80, ie, a finishing device.

After each copy is completed, residual toner and debris remaining on photoreceptor belt 10 are removed at cleaning station F by a combination of cleaning blade 90 and auger toner removal device 91 provided within housing 92. Can be removed. In the illustrated embodiment, the housing 92 is located above the photoreceptor belt 10, that is, at the 12 o'clock position. The removed residual toner can be stored for disposal or returned to the developer for reuse. before shifting the average value of the charge on the belt to expose residual toner and debris to positive and negative charges to narrow the charge distribution and to more effectively remove toner at cleaning station F. A cleaning corona generator may be provided. A toner recovery device may also be used to recover residual toner removed from the photoreceptor belt 10 for return by some known recovery devices.

Copying machine controller 98 preferably includes:
1 that controls all of the processes and functions of the copier mentioned above.
known programmable controllers or a combination of controllers. Controller 98 is responsive to various sensor devices and can perform diagnostic operations on a user interface (not shown) when necessary to enhance control of the copier.

As mentioned above, the copying machine according to the present invention has the following features:
It can be any of several well known devices. Changes and variations in the specific electrostatographic process, copy paper handling and control equipment may be made without affecting the invention.

According to the invention, the cleaning station F:
As shown in FIGS. 1 and 2, a pair of complementary (i.e. , uneven serrated blade 94
and 96. The term "serrated" means that the cleaning blade 97 of each blade has a portion that engages the photoreceptor and a portion that does not engage the photoreceptor. Areas that engage the photoreceptor substantially prevent toner from passing past the area, while areas that do not engage the photoreceptor allow toner to pass unhindered past the photoreceptor. make it possible. The term "complementary" or "staggered" means that the engaged portion of the first blade corresponds to the unengaged portion of the second blade in the direction across the photoreceptor, and The blade is supported such that the mating portion corresponds to the engaging portion of the second blade in the direction across the photoreceptor. As used herein, the term "complementary" or "staggered" is limited to the complete correspondence of the engaged portion of one blade with the non-engaged portion of the other blade. isn't it. However, it is certainly an example contemplated by the present invention to have the engaged portion of one blade correspond completely to the non-engaged portion of the other blade in this manner. Therefore, it is within the scope of the invention that the portion of the blade that engages the photoreceptor is substantially larger than the portion that does not engage the photoreceptor, and that the non-engaged area of one blade is the engaged area of the other blade. Configurations are included in which each of the blades is positioned relative to the other blade such that the blade is aligned with the other blade. The actual size of the engagement portion will depend on the performance of the blade material with respect to the electrostatographic device. A longer engagement portion will reduce the amount of "tucking" or downward bending of the engagement portion of the blade, while a shorter engagement portion will increase the agitation efficiency and distribute the toner evenly. It spreads to lubricate downstream cleaning blades. The blade material can be selected from any of the known blade materials with this condition in mind. Although not essential, the serrated blade may be made of the same or similar material to the cleaning blade. Each of the blades may be supported by a conventional blade holder 99, which may be mounted to the cleaning housing 92 or to the copier frame (not shown).

[0024]

[Effects of the Invention] The uneven serrated blade allows the toner to reach the solid (continuous blade) cleaning blade.
Enables blade lubrication required for blade-type cleaning equipment. In addition, the serrated blade acts as a toner disruptor, destroying the strong adhesion between the photoreceptor and the toner, thereby improving the cleaning efficiency of the solid (continuous blade) blade.

Of course, other cleaning position and blade shape combinations are within the scope of the present invention. The serrated blade in the wiping state can also be used in combination with a solid (continuous blade) doctor blade placed at the 12 o'clock position. Of course, other combinations are also possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a copying machine as an electrostatographic imaging apparatus incorporating the present invention.

FIG. 2 is a perspective view of a cleaning station incorporating the present invention.

[Explanation of symbols]

10 Photoreceptor belt, 11 Photoconductive surface, 14 Peeling roller, 16 Tension roller, 20 Drive roller, 21 Motor, 30 platen, 32 Flash lamp, 33 Lens, 34 Developer housing, 36 Developer housing, 42 Magnetic brush roll, 44 Magnetic brush roll, 46 Corona generator, 48 Corona generator, 49 Support, 70 Fixing assembly, 80 Finishing equipment, 90 Cleaning blade, 91 Toner removal device, 92 Cleaning housing, 94 blade, 96 blade, 98 controller.

Claims (1)

[Claims] 1. A charge retention surface driven in a process direction;
means for forming a latent image on the charge retentive surface; means for developing the latent image with toner; means for transferring the developed toner image to another surface; and means for transferring the developed toner image from the charge retentive surface. a cleaning device for removing residual toner from the charge retentive surface after cleaning the charge retentive surface, the cleaning device being supported vertically above a horizontally disposed portion of the charge retentive surface; a charge retentive surface supported within the cleaning housing across the charge retentive surface generally transverse to the direction of movement of the charge retentive surface and for removing toner from the charge retentive surface; a cleaning blade having a continuous cleaning blade held in engagement with and for cleaning; a toner transport means for discharging toner removed from the charge retentive surface; a first front cleaning blade and a second front cleaning blade supported within the cleaning housing substantially laterally across the charge retention surface upstream from the cleaning blade; Each is
It has a discontinuous cleaning blade consisting of a portion that engages with the charge retention surface and a portion that does not engage with the charge retention surface, and each of the first and second pre-cleaning blades has a discontinuous portion that engages with the charge retention surface. An electrostatic photographic image forming apparatus characterized in that the mating portion of the other cleaning blade is supported so as to be offset from the other cleaning blade in a direction transverse to the non-engaging portion of the other cleaning blade.