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US 5,313,359 AGranted
Excessive current preventing device for the contact charging of a photosensitive layer
AssigneeSharp Kabushiki Kaisha
InventorsShinji Imagawa, Koichi Inui
Life of this patent
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AssigneeSharp Kabushiki Kaisha
InventorsShinji Imagawa, Koichi Inui
Estimating the term…
A contact charger includes a photoreceptor having a photosensitive layer formed on a surface of an electrically conductive drum base and a fixed coil connected to the drum base and ground. The contact charger charges the photosensitive layer by making a charge roller in contact with the photosensitive layer while being applied thereto DC voltage from a power supply. With this arrangement, in the case where a pin hole exists on the photosensitive layer, there may have a continuity between the charge roller and the drum base which may results in a sudden increase in current flowing between the drum base and ground. When this happens, however, since self-induced electromotive force, having a direction opposite to the electromotive force of the power supply, is generated by the fixed coil in response to a sudden increase in current, excessive current will not flow between the drum base and ground, thereby eliminating the possibility of a large drop in voltage of the power supply. As a result, the contact charger is always capable of appropriately charging the surface of the photosensitive layer even in the case where a defect such as a pin hole exists on the photosensitive layer.
A contact charger for uniformly charging a photosensitive layer having a photoconductivity formed on a surface of an electrically conductive base of a photoreceptor, comprising:
A contact charger for uniformly charging a photosensitive layer having a photoconductivity formed on a surface of an electrically conductive base of a photoreceptor, comprising:
A contact charger for uniformly charging a photosensitive layer having a photoconductivity formed on a surface of an electrically conductive base of a photoreceptor, comprising:
A contact charger for uniformly charging a photosensitive layer having a photoconductivity formed on a surface of an electrically conductive base of a photoreceptor, comprising:
Dependencies are inferred from the claim text.