Image forming apparatus and cartridge having a charging roller with a surface layer including projections
First Claim
1. An image forming apparatus comprising:
- a photosensitive member;
a charging roller contacting the photosensitive member and configured to electrically charge the photosensitive member by being supplied with a voltage, wherein the charging roller has an outermost surface layer including an electroconductive resin material, first surface particles having an average particle size of more than 7 μ
m and less than 30 μ
m, and second surface particles having an average particle size of more than 2 μ
m and less than 6 μ
m, and wherein the first surface particles and the second surface particles are dispersed in the electroconductive resin material so as to form first projections formed by the first surface particles and second projections formed by the second surface particles, respectively, on a surface of the charging roller;
a cleaning roller contacting the charging roller and configured to clean a surface of the charging roller, wherein the cleaning roller includes a shaft portion and an elastic cleaning portion extending helically around the shaft portion;
an urging member configured to urge the cleaning roller against the charging roller; and
an image forming portion configured to form a toner image on the photosensitive member charged by the charging roller and configured to transfer the toner image onto a recording material,wherein the first projections have an average interval Sm of 0.1 mm or more and 0.6 mm or less, and the charging roller has a surface roughness Rz of 6 μ
m or more and 30 μ
m or less.
1 Assignment
0 Petitions
Accused Products
Abstract
An image forming apparatus includes a photosensitive member, a charging roller, a cleaning roller, an urging member and an image forming portion. The charging roller has an outermost surface layer including an electroconductive resin material, first surface particles having an average particle size of more than 7 μm and less than 30 μm and second surface particles having an average particle size of more than 2 μm and less than 6 μm. The first and second surface particles are dispersed in the electroconductive resin material so as to form first projections and second projections, respectively. The cleaning roller cleaning roller includes a shaft portion and an elastic cleaning portion extending helically around the shaft portion and having a rectangular cross-section perpendicular to an extending direction thereof.
21 Citations
14 Claims
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1. An image forming apparatus comprising:
-
a photosensitive member; a charging roller contacting the photosensitive member and configured to electrically charge the photosensitive member by being supplied with a voltage, wherein the charging roller has an outermost surface layer including an electroconductive resin material, first surface particles having an average particle size of more than 7 μ
m and less than 30 μ
m, and second surface particles having an average particle size of more than 2 μ
m and less than 6 μ
m, and wherein the first surface particles and the second surface particles are dispersed in the electroconductive resin material so as to form first projections formed by the first surface particles and second projections formed by the second surface particles, respectively, on a surface of the charging roller;a cleaning roller contacting the charging roller and configured to clean a surface of the charging roller, wherein the cleaning roller includes a shaft portion and an elastic cleaning portion extending helically around the shaft portion; an urging member configured to urge the cleaning roller against the charging roller; and an image forming portion configured to form a toner image on the photosensitive member charged by the charging roller and configured to transfer the toner image onto a recording material, wherein the first projections have an average interval Sm of 0.1 mm or more and 0.6 mm or less, and the charging roller has a surface roughness Rz of 6 μ
m or more and 30 μ
m or less. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A cartridge detachably mountable to an image forming apparatus, the cartridge comprising:
-
a photosensitive member; a charging roller contacting the photosensitive member and configured to electrically charge the photosensitive member by being supplied with a voltage, wherein the charging roller has an outermost surface layer including an electroconductive resin material, first surface particles having an average particle size of more than 7 μ
m and less than 30 μ
m, and second surface particles having an average particle size of more than 2 μ
m and less than 6 μ
m, and wherein the first surface particles and the second surface particles are dispersed in the electroconductive resin material so as to form first projections formed by the first surface particles and second projections formed by the second surface particles, respectively, on a surface of the charging roller;a cleaning roller contacting the charging roller and configured to clean a surface of the charging roller, wherein the cleaning roller includes a shaft portion and an elastic cleaning portion extending helically around the shaft portion; and an urging member configured to urge the cleaning roller against the charging roller, wherein the first projections have an average interval Sm of 0.1 mm or more and 0.6 mm or less, and the charging roller has a surface roughness Rz of 6 μ
m or more and 30 μ
m or less. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification