Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2002-07-10
2004-09-28
Goodrow, John L (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S058050, C430S066000
Reexamination Certificate
active
06797444
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electrophotographic photoreceptor, and a production method of said electrophotographic photoreceptor, in addition to an image forming method, an image forming apparatus, as well as a processing cartridge employing said electrophotographic photoreceptor.
BACKGROUND OF THE INVENTION
In recent years, most widely employed as electrophotographic photoreceptors (hereinafter occasionally referred simply to as photoreceptors) have been electrophotographic organic photoreceptors (hereinafter occasionally referred simply to as organic photoreceptors) comprising organic photoconductive materials. Organic photoreceptors exhibit advantages in that it is easy to develop materials corresponding to various types of light sources for exposure; it is possible to select materials which result in minimal environmental pollution; and the production cost is lower. However, disadvantages are that during production of a number of copies and prints, the surface of organic photoreceptors tends to suffer from degradation as well as abrasion due to their weak mechanical strength.
In order to achieve the various characteristics demanded as listed above, heretofore, various investigations have been conducted.
In order to enhance the durability of organic photoreceptors as described above, it has been strongly demanded to minimize the abrasion due to frictional contact with cleaning blades. As one of the approaches to satisfy said demand, techniques have been investigated in which a protective layer, having high strength, is provided on the surface of said photoreceptor. For example, Japanese Patent Publication Open to Public Inspection No. 6-118681 describes that employed as said protective layer is a hardenable siloxane resin comprising colloidal silica. However, when such protective layer is employed, which is comprised only of silica which is structured with three-dimensional repetition of a siloxane bond (being an Si—O—Si bond), problems have been noted in that its surface results in cracking; adhesion properties to the photosensitive layer are degraded; and the electrostatic characteristics of said photosensitive layer are deteriorated.
It was demonstrated that background staining as well as image blurring during repeated use was caused by the adsorption of ozone as well as NO
x
, which was generated upon charging the photoreceptor, onto the charge transfer structure section in the protective layer. Further, in a process that carries out blade cleaning, problems occur in which surface adsorption of such gases results in an increase in friction against the cleaning blade, whereby blade noise as well as insufficient cleaning tends to occur. In order to minimize said adsorption of ozone as well as NO
x
, it is effective to lower the surface free energy.
Further, proposed as an approach to enhance the abrasion resistance, as well as to improve adhesion properties to the photosensitive layer, is an organic-inorganic hybrid polymer which exhibits both characteristics of an organic polymer and a crosslinked siloxane condensation product component. For example, Japanese Patent Publication Open to Public Inspection No. 2000-221723 describes as a protective layer of an electrophotographic photoreceptor the protective layer comprising a polymer in which polysiloxane and a silyl modified (having a silyl group) vinyl based polymers is chemically combined. However, even though the abrasion resistance of the photoreceptor, having such a protective layer, is mechanically enhanced, the problems described below occur. Background staining, as well as image blurring, tends to occur during repeated use due to insufficient electrophotographic characteristics. Further, residual toner is not completely removed due to an increase in the torque between the photoreceptor and the cleaning blade, and blade noise (abnormal noise due to the friction between said cleaning blade and said photoreceptor) is generated. As a result, it has been found that the photoreceptor, having said protective layer, is not suitable as a photoreceptor for an electrophotographic system, the Carlson process, which is most widely employed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an electrophotographic photoreceptor which results in sufficient image density, exhibits excellent resolution, as well as excellent cleaning properties during repeated copying, does not generate blade noise due to low driving torque of the cleaning blade, and exhibits excellent durability in which the decrease in the thickness of the photosensitive layer is minimized; a production method of said electrophotographic photoreceptor; and also an image forming method, an image forming apparatus, and a processing cartridge using said electrophotographic photoreceptor.
The invention and its embodiments are described.
In an electrophotographic photoreceptor comprising an electrically conductive support having thereon a resinous layer, an electrophotographic photoreceptor wherein said resinous layer comprises a resin comprising an organic polymer component, and a siloxane condensation product component, as well as fluorine atom-containing particles.
In an electrophotographic photoreceptor comprising an electrically conductive support having thereon a resinous layer, an electrophotographic photoreceptor wherein said resinous layer comprises a resin comprising an organic polymer component, and a siloxane condensation product component, as well as a fluorine atom-containing resin and fluorine atom-containing particles in either of said components.
The electrophotographic photoreceptor, wherein said organic polymer component contains a fluorine atom.
The electrophotographic photoreceptor, wherein said organic polymer component is comprised of at least a copolymer of a vinyl monomer and a fluorine atom-containing vinyl monomer.
The electrophotographic photoreceptor, wherein said vinyl monomer is an acrylic acid ester monomer or a methacrylic acid ester monomer.
The electrophotographic photoreceptor, wherein the weight ratio of said vinyl monomer to said fluorine atom-containing vinyl monomer is from 1:0.01 to 1:2.
The electrophotographic photoreceptor, wherein at least one type of said vinyl monomers is a silane monomer represented by the Formula (1).
In the formula R
3
is a hydrogen atom, an alkyl having carbon atoms of from 7 to 16 or an aralkyl having carbon atoms of from 1 to 10, R
4
is an organic group having polymerizable double bond, X is a halogen atom or an alkoxy group, and n is an integer of from 1 to 3.
The electrophotographic photoreceptor, wherein said siloxane condensation product component contains a fluorine atom.
The electrophotographic photoreceptor, wherein said fluorine atom-containing particles are fluororesin particles.
The electrophotographic photoreceptor, wherein said fluorine atom-containing particles are those which are subjected to a surface treatment employing a silane compound containing a fluorine atom.
The electrophotographic photoreceptor, wherein said resinous layer is a surface layer.
In a production method of an electrophotographic photoreceptor which comprises an electrically conductive support having thereon at least a resinous layer, a production method of said electrophotographic photoreceptor wherein said resinous layer is formed by applying a coating composition comprising an organic polymer, having a silyl group in a side chain, a fluorine atom-containing silane compound, and fluorine atom-containing particles, and subsequently hardening the resultant coating.
In a production method of an electrophotographic photoreceptor which comprises an electrically conductive support having thereon at least a resinous layer, a production method of said electrophotographic photoreceptor wherein said resinous layer is formed by applying a coating composition comprising an organic polymer, having a fluorine atom-containing siloxane condensation product component in a side chain, and fluorine atom-containing particles, and subsequently hardening the resultant coating.
Th
Goodrow John L
Muserlian Lucas and Mercanti
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