Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
1999-07-29
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
C430S096000
Reexamination Certificate
active
06200715
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates in general to electrophotographic imaging members and, more specifically, to charge transport layers comprising a cross linked matrix derived from an aromatic polymer.
The formation and development of images on the surface of photoconductive materials by electrostatic means is well known. The basic electrophotographic imaging process, as taught by C. F. Carlson in U.S. Pat. No. 2,297,691, entails placing a uniform electrostatic charge on a photoconductive imaging member, exposing the imaging member to a light and shadow image to dissipate the charge on the areas of the imaging member exposed to the light, and developing the resulting electrostatic latent image by depositing on the image a finely divided electroscopic material known as toner. In the Charge Area Development (CAD) scheme, the toner will normally be attracted to those areas of the imaging member which retain a charge, thereby forming a toner image corresponding to the electrostatic latent image. This developed image may then be transferred to a substrate such as paper. The transferred image may subsequently be permanently affixed to the substrate by heat, pressure, a combination of heat and pressure, or other suitable fixing means such as solvent or overcoating treatment. Imaging members for electrophotographic imaging systems comprising selenium alloys vacuum deposited on substrates are known. Imaging members have also been prepared by coating substrates with photoconductive particles dispersed in an organic film forming binder. Coating of rigid drum substrates has been effected by various techniques such as spraying, dip coating, vacuum evaporation, and the like. Flexible imaging members can also be manufactured by processes that entail coating a flexible substrate with the desired photoconducting material.
Some photoresponsive imaging members consist of a homogeneous layer of a single material such as vitreous selenium, and others comprise composite layered devices containing a dispersion of a photoconductive composition. An example of a composite xerographic photoconductive member is described in U.S. Pat. No. 3,121,006, which discloses finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. Imaging members prepared according to the teachings of this patent contain a binder layer with particles of zinc oxide uniformly dispersed therein coated on a paper backing. The binders disclosed in this patent include materials such as polycarbonate resins, polyester resins, polyamide resins, and the like.
Photoreceptor materials comprising inorganic or organic materials wherein the charge generating and charge transport functions are performed by discrete contiguous layers are also known. Additionally, layered photoreceptor members are disclosed in the prior art, including photoreceptors having an overcoat layer of an electrically insulating polymeric material. Other layered photoresponsive devices have been disclosed, including those comprising separate photogenerating layers and charge transport layers as described in U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference.
Deposition of charge on the photoreceptor surface by bias charging rolls (BCR) is usually accompanied by significant degradation of the charge transport layer. This degradation is believed to be caused by plasma generated in the contact zone between the charging roll and the photoreceptor at breakdown electric fields. More specifically, bias roll charging of organic photoreceptors, particularly under alternating current conditions with the positive portion of the wave unfiltered, leads to significant degradation of the photoreceptor surface and undesirable reduction of the transport layer thickness. This degradation limits the useful life of the photoreceptor and is one reason why the use of bias charging rolls is currently limited to low volume printers and copiers. Preliminary test results indicate that overcoating of a charge transport layer with a cross linked charge transport polymer improves the resistance of the photoreceptor surface to BCR degradation. However, the use of such overcoat would require yet another coating step which can reduce production yields. Moreover, the overcoat itself often does not adhere to a small molecule/binder polymer transport layer underneath. Further, if a cross linked charge transport polymer is used as transport layer, this material may not have sufficient carrier mobility.
INFORMATION DISCLOSURE STATEMENT
U.S. Pat. No. 5,814,426 to T. Fuller et al. issued on Sep. 29, 1998—An imaging member is disclosed which comprises a conductive substrate, a photogenerating material, and a binder which comprises a polymer of specific formulae I, II, III, IV, V, VI, VII, VIII, IX or X as further described in the patent. These polymers may be used in a charge transport layer.
U.S. Pat. No. 5,874,192 to Timothy J. Fuller et al., issued Feb. 23, 1999—Disclosed is an imaging member which comprises a conductive substrate, a photogenerating material, a charge transport material, and a polymeric binder comprising (a) a first polymer comprising a polycarbonate, and (b) a second polymer of specified formulae I, II, III, IV, V, VI, VII, VIII, IX, or X as further defined therein. These binders may be used in a charge transport layer.
U.S. Pat. No. 5,761,809 to Fuller et al., issued Jun. 9, 1998—Disclosed is a process which comprises reacting a haloalkylated aromatic polymer with a material selected from the group consisting of unsaturated ester salts, alkoxide salts, alkylcarboxylate salts, and mixtures thereof, thereby forming a curable polymer having functional groups corresponding to the selected salt. Another embodiment of the invention is directed to a process for preparing an ink jet printhead with the curable polymer thus prepared.
U.S. Pat. No. 5,889,077 to Timothy J. Fuller et al., issued Mar. 30, 1999—Disclosed is a process which comprises reacting a polymer of specific formulae as further described in the patent, with (i) a formaldehyde source, and (ii) an unsaturated acid in the presence of an acid catalyst, thereby forming a curable polymer with unsaturated ester groups. Also disclosed is a process for preparing an ink jet printhead with the above polymer.
U.S. Pat. No. 5,882,814 to Timothy J. Fuller et al., issued Mar. 16, 1999—Disclosed is an imaging member which comprises a conductive substrate, a photogenerating layer, and a charge transport layer comprising a specified polymer of the formulae I, II, III, IV, V, VI, VII, VIII, IX, or X as further defined therein.
U.S. Pat. No. 5,739,254 to Timothy J. Fuller et al., issued Apr. 14, 1998—Disclosed is a process which comprises reacting a polymer of specified general formulae with an acetyl halide and dimethoxymethane in the presence of a halogen-containing Lewis acid catalyst and methanol, thereby forming a haloalkylated polymer. In a specific embodiment, the haloalkylated polymer is then reacted further to replace at least some of the haloalkyl groups with photosensitivity-imparting groups. Also disclosed is a process for preparing a thermal ink jet printhead with the aforementioned polymer.
U.S. Pat. No. 5,849,809 to Ram S. Narang et al., issued Dec. 15, 1998—Disclosed is a composition which comprises (a) a polymer containing at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of specified formulae, wherein said photosensitivity-imparting substituents are hydroxyalkyl groups; (b) at least one member selected from the group consisting of photoinitiators and sensitizers; and (c) an optional solvent. Also disclosed are processes for preparing the above polymers and methods of preparing thermal ink jet printheads containing the above polymers.
U.S. Pat. No. 5,863,963 to Ram S. Narang et al., issued Jan. 26, 1999—Disclosed is a process which comprises the steps of (a) providing
Fuller Timothy J.
Limburg William W.
Narang Ram S.
Pai Damodar M.
Renfer Dale S.
Haack John L.
Kondo Peter
Rodee Christopher D.
Xerox Corporation
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