Electrophotography – Cleaning of imaging surface – Retractable cleaning arrangement
Reexamination Certificate
2000-12-20
2002-08-06
Royer, William J. (Department: 2852)
Electrophotography
Cleaning of imaging surface
Retractable cleaning arrangement
C399S353000
Reexamination Certificate
active
06430387
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to electrostatographic image reproduction machines, and more particularly concerns an electrostatographic reproduction machine having a motion-defect-free cleaning method and assembly for preventing motion related image defects.
In an electrostatographic image reproduction machine, a photoconductive member is charged to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charge thereon in irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document being reproduced.
After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing developer material containing charged toner particles, for example, black toner particles, into contact therewith. Developer material can be single component comprised only of charged toner particles, or it may be dual component comprising carrier particles and toner particles that are triboelectrically charged when admixed or mixed with the carrier particles. In either case, bringing the developer material into contact with the latent image forms a toner image on the photoconductive member which is subsequently transferred to a copy sheet. The copy sheet is then separated from the photoconductive member and the toner powder is fed on the copy sheet through a fusing apparatus where it is heated to permanently affix it to the copy sheet, thus forming a black and white copy of the original document.
Multi-color electrostatographic image reproduction machines which use multi-colored toners are substantially identical in each color image forming process to the foregoing process of black and white image reproduction which uses only black toner. However, rather than forming a single latent image on the photoconductive member, several single color latent images corresponding to color separated light images of the original document are recorded thereon. Each single color electrostatic latent image is developed with toner particles of a color complementary thereto. This process may be performed in a single pass of the photoconductive member, or in multipasses thereof during which image formation is repeated over a plurality of cycles, for forming different colored images using their respective complementarily colored toner particles. Each single color toner powder image is thus formed on the photoconductive member in superimposed registration with the other toner powder images.
This creates a composite multi-layered toner powder image which is then transferred directly, or via an intermediate transfer member, onto a copy sheet. The copy sheet is then separated from the photoconductive member or from the intermediate transfer member and fed through a fusing apparatus for permanently affixing the toner image to the copy sheet. This creates a hard color copy of the original multi-color document.
In multipass multi-color image reproduction machines which have a photoconductive belt member, it is necessary for the cleaning system therein to be capable of engaging the photoconductive member to clean, as well as, retracting from the photoconductive member in order to allow image formation. In order to sustain a desired machine output rate, it is also necessary for the cleaning system to be accurately locatable “on the fly”.
Unfortunately, there is a major problem that results from motion quality disturbances as a retracted cleaner re-engages the photoconductive member “on the fly”. It has been found that conventional cleaning systems, such as brush cleaners with supporting frames that directly contact a photoconductor assembly itself, ordinarily cannot be located accurately for cleaning without the motion of such frames having an undesirable impact on the photoconductive member or photoreceptor, and thereby causing motion related defects or image disturbance defects. Conventional attempts to reduce such impact by reducing the speed of the cleaning housing or frame at contact, ordinarily result in unacceptably high levels of impact force.
There is therefore a need for a cleaning system that will solve such motion quality impact problems.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a motion-defect-free method of minimizing cleaning apparatus induced motion quality disturbances in a moving belt photoreceptor of a toner image reproduction. The method includes the steps of providing at least one resilient member to each side of the moving belt photoreceptor and at a desired belt cleaning station along a path of movement of the belt photoreceptor, and mounting a cleaning apparatus that includes a moveable frame having frame locating members, and at least one separately moveable cleaning member at the cleaning station. The motion-defect-free method also includes the steps of first moving the moveable frame into contact with each of the locating members, and for then separately moving, relative to the moveable frame, the at least one separately moveable cleaning member, into contact and cleaning engagement with the moving belt photoreceptor, thereby minimizing cleaning apparatus induced motion quality disturbances in the moving belt photoreceptor.
In accordance with another aspect of the present invention, there is provided a motion-defect-free cleaning assembly for minimizing cleaning apparatus induced motion quality disturbances in a moving belt photoreceptor of a toner image reproduction. The assembly includes at least one resilient member located to each side of the moving belt photoreceptor at a desired belt cleaning station along a path of movement of the belt photoreceptor, and a cleaning apparatus that is mounted at the cleaning station and that includes at least one separately moveable cleaning member and a moveable frame having frame locating members. The motion-defect-free assembly also includes a drive and control system for first moving the moveable frame into contact with each of the locating members and for then separately moving, relative to the moveable frame, the at least one separately moveable cleaning member into contact and cleaning engagement with the moving belt photoreceptor, thereby minimizing cleaning apparatus induced motion quality disturbances in the moving belt photoreceptor.
REFERENCES:
patent: 5669055 (1997-09-01), Thayer et al.
patent: 5930575 (1999-07-01), Fornalik et al.
LaTour Norman E.
Quesnel Lisbeth S.
Soures Nicholas M.
Nguti Tallam I.
Royer William J.
Xerox Corporation
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