Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2002-03-05
2004-04-20
Chapman, Mark A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S060000, C430S064000
Reexamination Certificate
active
06723480
ABSTRACT:
BACKGROUND TO THE PRESENT INVENTION
1. Field of the Invention
The present invention relates to a substrate for an electrophotography photosensitive body and an electrophotography photosensitive body that uses an electrophotography process with at least one contact charging method as a charging mechanism (henceforth referred to a contact charging process). The present invention also relates to an electrophotography device equipped with this photosensitive body.
2. Description of the Related Art
Traditionally, the technology for electrophotography had developed in the field of the copier machine.
Recently, it has also been applied to laser printers and the like, and compared to the prior impact printers, these laser printers are much improved in terms of image quality, speed, and quietness. The electrophotography photosensitive body mounted onto these devices is formed by providing a photoconductive layer on a surface of a conductive cylindrical substrate.
Photoconductive organic materials are typically included in the materials for this photoconductive layer. In general, its layer structure is a function-separated structure (layered type). This layered type is commonly a negative charging type photosensitive body in which an undercoat layer (UCL), a charge generating layer (CGL), and a charge transport layer (CTL) are laminated in that order on top of an aluminum substrate.
For the undercoat layer, a layer that is primarily of a polyamide resin is commonly used. However, although this undercoat layer is inexpensive, there are many problems in terms of environmental resistance. In particular, there can be significant fluctuations in its properties due to humidity. As a way to combat this problem, instead of the polyamide resin film described above, an anodic oxidation film that is formed by anodic oxidation treatment of an aluminum substrate is used as the undercoat layer. In particular, in high temperature and high humidity environments, the anodic oxidation film is thought to have better reliability.
In the related art, a corona charging method is often used for the charging mechanism in the electrophotographic process. However, recently, for the purposes of improving charging efficiency and miniaturizing the device and reducing ozone amounts and the like, devices that use a contact charging method have been increasing.
The contact charging method conducts charging by direct contact of the charging member with the photosensitive body surface. However, with the contact charging method, any small irregularities on the substrate surface can easily result in damage to the insulation of the photosensitive layer.
In addition to contact charging devices used in charging processes in the electrophotography process, the contact charging devices described here also include devices that charge by contact with the electrophotography photosensitive body such as contact transfer devices used in a transfer process and the like.
With contact transfer, because paper and the like are normally present between the photosensitive body and the contact transfer device, insulation damage does not readily occur. However, with cut paper, direct contact between the photosensitive body and the contact transfer device cannot be avoided between one page and the next. As a result, damage to insulation is similarly a problem.
In particular, when OHP sheets are used, because the transfer voltage becomes high, insulation damage occurs readily. Stated more concretely, when small defects in the material on the substrate surface or small splinters from cutting the substrate surface are present, the electric field becomes concentrated in that area when voltage is applied, and damage to the insulation occurs.
When damage to the insulation occurs, in reverse developing systems, this results in black spots on white parts, and in normal developing, this becomes white spots in black parts. When these spots are numerous, they can prove to be a serious printing obstacle. In particular, in the case of reverse developing, even small black dots appear readily, and this becomes a frequent problem.
Various improvements have been proposed for this problem arising from insulation damage. For example, Japanese Patent Number 2661418, discloses a method for anodic oxidation of the surface of the aluminum substrate used for the photosensitive body.
Unfortunately, after a detailed examination by the present inventors, by using this method alone, only the problem of comparatively large printing defects of diameter 0.5 mm or greater was sightly minimized, and the practical problem of minute printing defects (diameter of approximately 0.1-0.5 mm) due to leakage (insulation damage) during charging was not sufficiently resolved. Consequently, this disclosure has not proved successful in solving the problems noted above.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the concerns raised and discussed above.
It is another object of the present invention is to provide an electrophotography photosensitive body substrate and an electrophotography photosensitive body in which an electrophotography photosensitive body, wherein the body includes a substrate having a sealed aluminum anodic oxidation film on its surface and a photosensitive layer on top of this substrate surface, and used in a contact charging process, and thereby prevent the creation of small insulation damage of around diameter 0.1-0.5 mm.
It is another object is to provide an electrophotography device using this photosensitive body.
It is another object of the present invention is to provide the above substrate, electrophotography photosensitive body, and electrophotography device that are used in a contact charging system of a reverse developing system.
According to one embodiment of the present invention, the above object is achieved by an electrophotography photosensitive body substrate having an aluminum anodic oxidation film on its surface and being used in a contact charging process, wherein: the anodic oxidation film is a film that is sealed by a sealing agent in which an anion surface active agent is added.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate, wherein: the sealed aluminum anodic oxidation film is a film that is sealed by a sealing agent in which an anion surface active agent is added in an amount necessary for preventing the formation of sealing deposits.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate as described in any embodiment supported, wherein: a phosphoric ester surface active agent is used as the anion surface active agent.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate as described in any embodiment above or below, wherein: the phosphoric ester surface active agent has a concentration of 0.1-2.0 g/l with respect to water.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate as described in any embodiment above or below, wherein: a formaldehyde condensate of naphthalene sulfonate is used as the anion surface active agent.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate as described any embodiment above, wherein: the formaldehyde condensate of naphthalene sulfonate has a concentration of 0.1-3.0 g/l with respect to water.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate as described any embodiment provided herein, wherein: a formaldehyde condensate of bisphenol A sulfonate is used as the anion surface active agent.
According to another embodiment of the present invention, there is provided an electrophotography photosensitive body substrate as described in each embodiment discussed, wherein: the formaldehyde condensate of bisphenol A sulfona
Kobashi Masaru
Nakagishi Yutaka
Nishimaki Shinichiro
Sakaguchi Masaaki
Senba Naoyuki
Chapman Mark A.
Darby & Darby
Fuji Electric Imaging Device Co. Ltd.
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