Gap adjustment of non-contact charging roller
AssigneeHewlett-Packard Development Company, L.P.
InventorsYoichi Yoshida, Yasuyuki Ishii, Koichiro Takashima
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Abstract
An image forming apparatus includes: an image carrier having a first rotation axle, a charging roller having a second rotation axle, a conductive member to contact a surface of the image carrier, a gap size acquisition device, and a gap adjustment device. The charging roller is disposed adjacent to the image carrier in a non-contact manner across a gap to charge the image carrier. The gap size acquisition device acquires a size of the gap. The gap adjustment device adjusts a distance between the first rotation axle and the second rotation axle based on information from the gap size acquisition device to maintain the size of the gap within a predetermined range.
Claims20
An image forming apparatus comprising:
- an image carrier having a first rotation axle;
- a charging roller having a second rotation axle extending parallel with the first rotation axle, the charging roller being disposed adjacent to the image carrier in a non-contact manner to charge the image carrier, wherein a gap is formed between the charging roller and the image carrier;
- a conductive member to contact a surface of the image carrier;
- a gap size acquisition device to acquire a first voltage-current characteristic associated with a surface film thickness of the image carrier, to acquire a second voltage-current characteristic associated with a sum of the surface film thickness of the image carrier and a size of the gap, and to acquire the size of the gap based on the first voltage-current characteristic and the second voltage-current characteristic;
- and
- a gap adjustment device to adjust a distance between the first rotation axle and the second rotation axle based on information acquired from the gap size acquisition device, to maintain the size of the gap within a predetermined range.
A method of adjusting a size of a gap in an image forming apparatus including a charging roller disposed adjacent to a rotatable image carrier in a non-contact manner across the gap, comprising:
- applying a first voltage to a conductive member that is in contact with a surface of the image carrier to detect a first current through the image carrier, thereby acquiring a first voltage-current characteristic associated with a surface film thickness of the image carrier;
- applying a second voltage to the charging roller to detect a second current through the image carrier, thereby acquiring a second voltage-current characteristic associated with a sum of the surface film thickness of the image carrier and a size of the gap;
- acquiring the size of the gap based on the first voltage-current characteristic and the second voltage-current characteristic;
- and
- adjusting a distance between a rotation axle of the charging roller and a rotation axle of the image carrier based on the size of the gap acquired.
An image forming apparatus comprising:
- an image carrier having a first rotation axle;
- a charging roller having a second rotation axle extending parallel with the first rotation axle, the charging roller being disposed adjacent to the image carrier in a non-contact manner to charge the image carrier, wherein a gap is formed between the charging roller and the image carrier;
- a conductive member to contact a surface of the image carrier;
- and
- a gap size acquisition device to:
- apply a first voltage to the conductive member to detect a first current through the image carrier, and to thereby acquire a first voltage-current characteristic associated with a surface film thickness of the image carrier,
- apply a second voltage to the charging roller to detect a second current through the image carrier, and to thereby acquire a second voltage-current characteristic associated with a sum of the surface film thickness of the image carrier and the size of the gap, and
- acquire the size of the gap based on the first voltage-current characteristic and the second voltage-current characteristic;
- and
- a gap adjustment device to adjust a distance between the first rotation axle and the second rotation axle based on information acquired from the gap size acquisition device.
Dependencies are inferred from the claim text.