1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member comprised of a protective layer containing particular resin and a photosensitive layer containing a particular compound. The present invention also relates to an electrophotographic apparatus and process cartridge.
2. Description of the Prior Art
An electrophotographic photosensitive method, as described in the specification of U.S. Pat. No 2,297,691, uses a photoconductive material which is an insulator in the dark, but has a changeable electrical resistance according to quantity of light. The main characteristics which the electrophotographic member requires are as follows.
(1) To be charged to a suitable voltage in the dark. PA1 (2) To maintain the suitable voltage in the dark. PA1 (3) To lose charge promptly when irradiated with light.
In particular, since a surface of a photosensitive member is liable to damage by external electrical and mechanical forces caused by a charger, an image exposure means, a development means and a cleaning means, the photosensitive member is required to withstand those external forces. In other words, an electrophotographic photosensitive member (hereinbelow referred to as "a photosensitive member") is required to have durability against electrical deterioration caused by ozone or nitrogen oxide which are generated during the step of corna charging, and against mechanical deterioration caused by contact with other components. Especially, it is desired to improve the durability of a photosensitive member based on an organic photoconductive substance.
To improve the durability of a photosensitive member, it has been tried to provide, on the photosensitive layer a protective layer, containing resin as a main ingredient. For instance, Japanese Laid-Open Patent Application No 56-42863 and No 53-103741 disclose that a protective layer containing setting type resin improves the durability of the photosensitive member. However, when such setting type resin is used as a protective layer which contains resin as a main ingredient, the protective layer or the photosensitive layer may crack, because the protective layer shrinks. For the purpose of solving this problem, it is proposed in Japanese Laid Open Patent Application No 5-100464 to use an acrylic type monomer as the setting type resin.
USPTO Backgrounds
USPTO Backgrounds