Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
1998-02-10
2001-02-13
Dote, Janis L. (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S056000, C430S058150, C430S058250, C430S058350, C430S058500, C430S059600, C430S072000, C430S074000, C430S075000, C430S078000, C430S096000
Reexamination Certificate
active
06187493
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotosensitive material which is used for image forming apparatuses utilizing an electrophotography, such as electrostatic copying machine, laser beam printer, etc.
The electrophotography such as Carlson process includes a step of uniformly charging the surface of an electrophotosensitive material by a corona discharge; an exposure step of exposing the surface of the charged electrophotosensitive material to form an electrostatic latent image on the surface of the electrophotosensitive material; a developing step of bringing the formed electrostatic latent image into contact with a developer to visualize the electrostatic latent image due to a toner contained in the developer to form a toner image; a transferring step of transferring the toner image on a paper; a fixing step of fixing the transferred toner image; and a cleaning step of removing the toner remained on the photosensitive material.
As the electrophotosensitive material to be used for the above electrophotography, there have recently been suggested various organic photoconductors using an organic photoconductive compound having little toxicity in place of an inorganic photoconductive material (e.g. selenium, cadmium sulfide, etc.) whose handling is difficult because if it's toxicity. Such an organic photoconductor has an advantage such as good processability, easy manufacturing and great deal of freedom for design of performance.
As the organic photoconductor, a distributed function photosensitive layer containing an electric charge generating layer which generates an electric charge by light irradiation, and an electric charge transferring layer which transfer the generated electric charge is exclusively used.
A lot of studies about a binding resin which contains the above electric charge generating material and electron transferring material (consisting of hole transferring material and/or electron transferring material) and constitutes a photosensitive layer have been made so as to increase a mechanical strength (e.g. wear resistance, scratch resistance, etc.) of the photosensitive layer to prolong the life of the photoconductor. Particularly, polycarbonate resins (e.g. bisphenol A type, C type, Z type, fluorine-containing type, biphenyl copolymer type, etc.) have widely been utilized (Japanese Laid-Open Patent Publication Nos. 60-172045, 60-192950, 61-62039, 63-148263, 63-273064, 5-80548 and 5-88396).
In addition, it has also been known that the mechanical strength of the photosensitive layer is improved by increasing the molecular weight of the above polycarbonate resin (Japanese Laid-Open Patent Publication Nos. 5-113671 and 5-158249).
The mechanical strength of the photosensitive layer is improved by using the above-described polycarbonate resin as the binding resin, but the degree of the improvement is insufficient. In addition, the polycarbonate resin is inferior in compatibility with electric charge transferring material and despersion properties and, therefore, characteristics thereof can not be sufficiently utilized even if a material having excellent hole transferring characteristics is used. Accordingly, the sensitivity becomes inferior.
Furthermore, regarding a single-layer type photoconductor containing an electric charge transferring material and an electric charge generating material in a single layer, when using the polycarbonate resin as the binding resin in the photosensitive layer, the photosensitive layer is peeled off from a conductive substrate while using because the polycarbonate resin is inferior in adhesion to the conductive substrate such as aluminum, etc.
SUMMARY OF THE INVENTION
It is a main object of the present invention is to provide an electrophotosensitive material comprising a photosensitive layer in which a charge transferring material is uniformly dispersed in a binding resin, the electrophotosensitive material being superior in sensitivity.
It is another object of the present invention to provide an electrophotosensitive material provided with a photosensitive layer having a high mechanical strength such as wear resistance, etc. and being superior in adhesion to substrate.
The present inventors have studied intensively in order to accomplish the above objects. As a result, it has been found that, by using a specific electric charge transferring material, i.e. hole transferring material or electron transferring material, in combination with a specific polyester resin, the compatibility and dispersion properties of the electric charge transferring material to polyester resin are improved and, therefore, high electric charge transferring characteristics of the electric charge transferring material are fully exhibited, thereby improving the sensitivity of the photosensitive material.
The above specific polyester resin is superior in adhesion to conductive substrate and, therefore, the photosensitive layer is not likely to peel off from the conductive substrate while using the photosensitive material for a long period of time. Furthermore, the above polyester resin is also superior in mechanical strength such as wear resistance, etc. and, therefore, it becomes possible to prolong the life of the photosensitive material.
That is, the present invention provides an electrophotosensitive material comprising a conductive substrate and a photosensitive layer provided on the conductive substrate, the photosensitive layer comprising a binding resin of a polyester resin which is a substantially linear polymer obtained by using dihydroxy compounds represented by the following general formulas (1), (2) and (3), an electric charge generating material, and at least one of a hole transferring material selected from the group consisting of compounds represented by the following general formulas (HT1) to (HT13) and/or at least one of an electron transferring material selected from the group consisting of compounds represented by the following general formulas (ET1) to (ET14).
<Dihydroxy compounds>
General formula (1):
wherein R
1
is an alkylene group having 2 to 4 carbon atoms; and R
2
, R
3
, R
4
and R
5
are the same or different and indicate a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group
General formula (2):
wherein R
1
, R
2
, R
3
, R
4
and R
5
are as defined above; and n is an integer of not less than 2, preferably integer of 2 to 5
General formula (3):
wherein R
1
, R
2
, R
3
, R
4
and R
5
are as defined above; and R
6
and R
7
are the same or different and indicate an alkyl group having 1 to 10 carbon atoms
<Hole transferring material>
wherein R
8
, R
9
, R
10
, R
11
, R
12
and R
13
are the same or different and indicate a halogen atom, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, alkoxy group and aryl group may have a substituent; and a, b, c, d, e and f are the same or different and indicate an integer of 0 to 5
wherein R
14
, R
15
, R
160
, R
17
and R
18
are the same or different and indicate a hologen atom, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, alkoxy group and aryl group may have a substituent; and g, h, i, j and k are the same or different and indicate an integer of 0 to 5
wherein R
19
, R
20
, R
21
and R
22
are the same or different and indicate a halogen atom, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, alkoxy group and aryl group may have a substituent; R
23
are the same or different and indicate a halogen atom, a cyano group, a nitro group, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, alkoxy group and aryl group may have a substituent; m, n, o and p are the same or different and indicate an integer of 0 and 5; and q is an integer of 0 to 6
wherein R
24
, R
25
, R
26
and R
27
are the same or different and indicate a halogen atom, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, alkoxy group and aryl group may have a substituent; and r, s, t and u are the same or different and indicate an integ
Ihara Mitsuo
Katsukawa Masato
Nakamura Yuka
Sugase Ayako
Urano Akiyoshi
Dote Janis L.
Kyocera Mita Corporation
Smith , Gambrell & Russell, LLP
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