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US 5,852,758 AGranted
Charge roller displacement mechanism
AssigneeHewlett-Packard Company
InventorMark Wibbels
Life of this patent
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AssigneeHewlett-Packard Company
InventorMark Wibbels
Estimating the term…
A charge roller displacement mechanism prevents the build up of a sharply defined circumferential ring of contaminants on the surface of a charge roller in an electrophotographic printing system, thereby reducing the severity of the print defect caused by the contaminants. By cyclically laterally displacing the charge roller parallel to the longitudinal axis of a photoconductor drum as the photoconductor drum rotates, contaminants which reach the surface of the charge roller will not form a sharply defined circumferential ring that interferes with the uniform charging of a photoconductor drum charged by the charge roller. The charge roller displacement mechanism includes a first gear that engages the gear used to rotate paddles in a waste hopper of an electrophotographic printer cartridge. A second gear engages the first gear to provide a reduction of approximately 400 to 1. The charge roller is forced against a face of the second gear by a spring or, alternatively, by angling the longitudinal axis of the charge roller with respect to the longitudinal axis of the photoconductor drum. The face of the second gear contacting the charge roller includes a lobe. As the second gear rotates, the charge roller is laterally displaced across the surface of the photoconductor drum. The lobe is shaped so that one rotation of the second gear corresponds to one cycle of displacement of the charge roller.
A charge roller displacement mechanism for laterally displacing a charge roller relative to a photoconductor in an electrophotographic printing system, the charge roller displacement mechanism comprising:
An electrophotographic print cartridge, comprising:
An electrophotographic printing system, comprising:
In an electrophotographic printing system employing a photoconductor having a longitudinal axis, a charge roller having a longitudinal axis and contacting the photoconductor, and a charge roller displacement mechanism contacting the charge roller, a method for reducing the severity of print defects resulting from charge roller contamination comprising the steps of:
Dependencies are inferred from the claim text.