Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
1999-12-01
2001-03-13
RoDee, Christopher D. (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S056000, C430S970000, C430S133000
Reexamination Certificate
active
06200714
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a photoconductor for electrophotography (hereinafter referred to as an “electrophotographic photoconductor” or simply as a “photoconductor”). Specifically, the present invention relates to an electrophotographic photoconductor that includes a photosensitive film containing organic materials on an electrically conductive substrate. The photoconductor is used in printers, copying machines and facsimiles which employ electrophotographic techniques.
It is necessary for photoconductors to retain surface charges in the dark, to generate electric charges in response to received light, and to transport the generated electric charges in response to the received light. Photoconductors may be classified into monolayered photoconductors, which have a layer that exhibits all the above described functions, and laminate-type photoconductors, which have a layer for charge generation and another layer for charge transport upon exposure to light and surface charge retention in the dark.
Conventional photoconductors employ the Carlson method for electrophotographic image formation. Image formation by the Carlson method includes the steps of charging the photoconductor in the dark by corona-discharge, forming electrostatic latent images of the original letters and pictures on the charged surface of the photoconductor, developing the electrostatic latent images with toner, and transferring the developed toner images to the carrier paper. The photoconductor is ready to be used again after steps of discharge, removal of residual toner and optical discharge are completed.
Inorganic photoconductive materials such as selenium, selenium alloys, zinc oxide and cadmium sulfide have been used as the photosensitive material for the above described photoconductors. The inorganic photoconductive materials are dispersed into a resin binder. Organic photoconductive materials such as poly-N-vinylcarbazole, 9,10-anthracenediolpolyester, hydrazone, stilbene, butadiene, benzidine, phthalocyanine and bisazo compounds have also been used as the photosensitive material for the above described photoconductors. The organic photoconductive materials are dispersed into a resin binder or deposited by vacuum deposition or by sublimation.
If necessary, various ingredients are added to the photosensitive film to improve the electrophotographic properties of the photoconductor. For example, German Patent No. 3 625 766 discloses phosphite compounds as phosphorous-containing additives. Althoughvarious additives have been examined to improve the stability of the photoconductor, a satisfactory effect has not been obtained to date.
OBJECTS AND SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the invention to provide an electrophotographic photoconductor that improves its electrophotographic properties by employing a new additive. It is another object of the invention to provide a method of manufacturing an electrophotographic photoconductor that improves the stability of the coating liquid for the photosensitive film of the photoconductor.
As used herein, the term “alkyl” is defined to include substituted or unsubstituted straight or branched carbon chains.
The inventors of the present invention have examined various additives to achieve the foregoing objects and found that a phosphinate compound contained in the photosensitive film greatly improves the electrophotographic properties of the photoconductor.
The inventors of the present invention have also found that a phosphinate compound contained in the coating liquid for the photosensitive film greatly improves the stability of the coating liquid.
Briefly stated, the present invention provides a photoconductor for electrophotography including an electrically conductive substrate and a photosensitive film on the electrically conductive substrate. The photosensitive film contains a charge transport agent and a phosphinate compound. The photoconductor may be of either a monolayer or a laminate construction.
According to another embodiment of the present invention, a method for making a photoconductor for electrophotography comprises the steps of producing a coating layer for a photosensitive film containing a phosphinate compound and then coating the photosensitive film onto a conductive substrate.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.
REFERENCES:
patent: 5945243 (1999-08-01), Nakamura et al.
patent: 5-53348 (1993-03-01), None
Chemical Abstracts 120:19204, 1994.
Borsenberger, Paul M. et al. Organic Photoreceptors for Imaging Systems. New York: Marcel-Dekker, Inc. pp. 289-293, 1993.
Grant, Roger et al. Chemical Dictionary. New York: McGraw-Hill, Inc. p. 444, 1987.
Hara Kenichi
Kina Hideki
Nakamura Yoichi
Ootani Akira
Sasaki Teruo
Fuji Electric Imaging Device Co. Ltd.
Morrison Law Firm
Rodee Christopher D.
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