Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2000-02-17
2001-07-24
Chapman, Mark (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S059100, C430S059400
Reexamination Certificate
active
06265122
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electrophotographic photoreceptor, and an image forming apparatus as well as a process cartridge using the same.
BACKGROUND OF THE INVENTION
In recent years, in order to write data which are subjected to digital signal treatment, an electrophotographic image forming method has increasingly been employed in which an organic photoreceptor is subjected to dot light exposure to form an electrostatic latent image followed by forming an image employing reversal development.
It is required that a photoreceptor, which is employed in such a method, is stable over an extended period of time and also suitable for writing requiring high resolution. Generally, compared to inorganic photoreceptors, organic photoreceptors readily respond to various types of exposure light sources because the selection range of materials for said organic photoconductors is wider. In addition, the electric potential of organic photoconductors is more stable. Accordingly, techniques employing organic photoconductors have been inevitable, especially for a process which is required for high image quality. Specifically, as charge generating materials which are required to obtain an electrophotographic photoreceptor which exhibits high sensitivity in the long wavelength region which is capable of corresponding to semiconductor laser as well as LED which have been increasingly employed, and excellent durability, phthalocyanines as well as perylenes exhibit excellent properties.
On the other hand, the strength of organic photoconductors is low. Due to that, a photosensitive layer comprised of organic photoconductors is likely to suffer problems due to abrasion wear and scratches, and enhancement of the durability has been sought. As a method to overcome such a problem, considered is a combination of phthalocyanine or perylene, which exhibits high sensitivity in the long wavelength region, as well as excellent stability of electric potential with a surface layer which itself exhibits excellent strength.
However, when the aforementioned combination is applied to a photoreceptor comprised of phthalocyanine, a problem occurs in which interference fringes, due to laser beam exposure, tends to appear on the resultant images. It is thus necessary to solve this problem.
Further, a surface layer is required which can maintain the high sensitivity as well as electric potential properties of phthalocyanine as well as perylene. For instance, in these photosensitive layers, the efficiency of carrier generation for variation in the thickness of the photosensitive layer largely depends on the strength of the electric field and the layer abrasion wear results in large variation in sensitivity. Specifically, when the abrasion wear is extensive, charging properties as well as light decay properties are greatly affected. When the charge potential is lowered, background stain is formed, while when the light decay is not sufficient, problems, such as an decrease in density and the like, occur.
Consequently, a layer structure is required which exhibits high sensitivity, and further, can maintain and stabilize the resulting high sensitivity.
SUMMARY OF THE INVENTION
It is an object of the present invention to enhance surface strength properties, while maintaining high sensitivity. It is another object of the present invention to maintain excellent electric properties and specifically to enhance the stability of the electric potential. It is still another object of the present invention to provide a photoreceptor which exhibits minimum variation in the thickness of said photoreceptor during use over an extended period of time, and as a result, exhibits stable properties over an extended period of time. It is a further object of the present invention to minimize effects due to interference fringes due to laser beam exposure, while maintaining excellent electric properties.
The aforementioned objects are realized employing a electrophotographic photoreceptor described below, and an image forming apparatus and a process cartridge using the same. The present invention and its embodiments are described.
An electrophotographic photoreceptor comprising an electrically conductive support, a photosensitive layer containing titanyl phthalocyanine having crystal structure provided on the support and a protective surface layer provided on the photosensitive layer, wherein the protective surface layer contains structural units having charge transportability and a siloxane resin having a cross linking structure.
The titanyl phthalocyanine preferably has a maximum peak of Bragg angle (2&thgr;±0.2°) at 27.20 with respect to Cu-K&agr; ray.
The titanyl phthalocyanine preferably further has a maximum peak of Bragg angle (2&thgr;±0.2°) at 9.6° with respect to Cu-K&agr; ray.
The protective surface layer of said electrophotographic photoreceptor preferably is comprised of a siloxane resin having a cross linking structure obtained by allowing an organic silicon compound having a hydroxyl group or a hydrolyzable group to react with a compound comprising structural units having a hydroxyl group as well as charge transportability.
The protective surface layer preferably comprises an antioxidant.
The preferable example of the antioxidant is either hindered amine compound or hindered phenol compound.
An electrophotographic photoreceptor comprising an electrically conductive support, a photosensitive layer containing perylene compound provided on the support and a protective surface layer provided on the photosensitive layer, wherein the protective surface layer contains structural units having charge transportability and a siloxane resin having a cross linking structure. An electrophotographic photoreceptor comprising an electrically conductive support, a photosensitive layer containing titanyl phthalocyanine having crystal structure provided on the support and a protective surface layer provided on the photosensitive layer, wherein the protective surface layer contains structural units having charge transportability and a siloxane resin having a cross linking structure.
In the electrophotographic photoreceptor which comprises an electrically conductive support having thereon a multilayer composed of a photosensitive layer and a protective surface layer in said order, an electrophotographic photoreceptor characterized in that said protective surface layer comprised of a layer comprising structural units having charge transportability, as well as siloxane based resins having a cross linking structure, and said photosensitive layer comprises titanyl phthalocyanine having a maximum peak of Bragg angle (2&thgr;±0.2°) at 27.2° with respect to Cu-K&agr; ray.
The electrophotographic photoreceptor wherein said titanyl phthalocyanine has a maximum peak of Bragg angle (2&thgr;±0.2°) at 27.2° with respect to Cu-K&agr; ray and a peak at 9.6°.
In an electrophotographic photoreceptor which comprises an electrically conductive support having thereon a multilayer composed of a photosensitive layer and a protective surface layer in said order, an electrophotographic photoreceptor characterized in that said protective surface layer comprises structural units having charge transportability, as well as siloxane based resins having a cross linking structure, and said photosensitive layer comprises titanyl phthalocyanine having a maximum peak of Bragg angle (2&thgr;±0.2°) at 26.2° with respect to Cu-K&agr; ray.
In an electrophotographic photoreceptor which comprises an electrically conductive support having thereon a multilayer composed of a photosensitive layer and a protective surface layer in said order, an electrophotographic photoreceptor characterized in that said protective surface layer comprises structural units having charge transportability as well as siloxane based resins having a cross linking structure, and said photosensitive layer comprises titanyl phthalocyanine having a maximum peak of Bragg angle (2&thgr;±0.2°) at 7.5° with respect to Cu-K&agr; ray.
In an electrophotogra
Itami Akihiko
Kitahara Yohko
Kurachi Masahiko
Oshiba Takeo
Sakimura Tomoo
Bierman Jordan B.
Bierman, Muserlian and Lucas
Chapman Mark
Konica Corporation
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