Electrophotographic photoreceptor, process cartridge, and image forming apparatus
An electrophotographic photoreceptor includes a conductive substrate, an organic photosensitive layer, and an inorganic protection layer arranged in this order, the inorganic protection layer containing a metal oxide that contains oxygen atoms, gallium atoms, and aluminum atoms.
1 . An electrophotographic photoreceptor comprising:
a conductive substrate;
an organic photosensitive layer; and
an inorganic protection layer arranged in this order, the inorganic protection layer containing a metal oxide that contains oxygen atoms, gallium atoms, and aluminum atoms,
wherein the inorganic protection layer has a first region present on an outer peripheral surface side and a second region that is closer to the conductive substrate than the first region is to the conductive substrate, and
a ratio I Al /(I Ga +I Al ) of an aluminum atomic weight fraction I Al to a total of a gallium atomic weight fraction I Ga and the aluminum atomic weight fraction I Al as measured by X-ray photoelectron spectroscopy is larger in the second region than in the first region.
2 . The electrophotographic photoreceptor according to claim 1 , wherein, in the inorganic protection layer, an average of the ratio I Al /(I Ga +I Al ) of the aluminum atomic weight fraction I Al to the total of the gallium atomic weight fraction I Ga and the aluminum atomic weight fraction I Al as measured by X-ray photoelectron spectroscopy in each of the first region and the second region is 0.5 or more and 1 or less.
3 . The electrophotographic photoreceptor according to claim 2 , wherein, in the inorganic protection layer, the average of the ratio I Al /(I Ga +I Al ) of the aluminum atomic weight fraction I Al to the total of the gallium atomic weight fraction I Ga and the aluminum atomic weight fraction I Al as measured by X-ray photoelectron spectroscopy in each of the first region and the second region is 0.7 or more and 1 or less.
4 . The electrophotographic photoreceptor according to claim 1 , wherein the second region has an average thickness larger than an average thickness of the first region.
5 . The electrophotographic photoreceptor according to claim 1 , wherein the organic photosensitive layer contains silica particles.
6 . The electrophotographic photoreceptor according to claim 5 , wherein the organic photosensitive layer has a charge generation layer and a charge transport layer that contains at least a charge transport material and silica particles.
7 . A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 1 .
8 . A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 2 .
9 . A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 3 .
10 . A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 4 .
11 . A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 5 .
12 . A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 6 .
13 . An image forming apparatus comprising:
the electrophotographic photoreceptor according to claim 1 ;
a charging device that charges a surface of the electrophotographic photoreceptor;
an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing device that develops the electrostatic latent image on the surface of the electrophotographic photoreceptor by using a developer containing a toner so as to form a toner image; and
a transfer device that transfers the toner image onto a surface of a recording medium.
14 . An image forming apparatus comprising:
the electrophotographic photoreceptor according to claim 2 ;
a charging device that charges a surface of the electrophotographic photoreceptor;
an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing device that develops the electrostatic latent image on the surface of the electrophotographic photoreceptor by using a developer containing a toner so as to form a toner image; and
a transfer device that transfers the toner image onto a surface of a recording medium.
15 . An image forming apparatus comprising:
the electrophotographic photoreceptor according to claim 3 ;
a charging device that charges a surface of the electrophotographic photoreceptor;
an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing device that develops the electrostatic latent image on the surface of the electrophotographic photoreceptor by using a developer containing a toner so as to form a toner image; and
a transfer device that transfers the toner image onto a surface of a recording medium.
16 . The image forming apparatus according to claim 13 , wherein the developer contains a carrier.
17 . The image forming apparatus according to claim 16 , wherein the carrier has a volume resistivity of 5×10 −7 Ω·cm or less and 5×10 −9 Ω·cm or more.