Charging roller with blended ceramic layer
AssigneeAmerican Roller Company
InventorBruce E. Hyllberg
Life of this patent
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Abstract
A charging roller for use in a xerographic copying machine includes a cylindrical roller core, and a ceramic layer formed by plasma spraying a blend of an insulating ceramic material and a semiconductive ceramic material in a ratio which is selected to control an RC circuit time constant of the ceramic layer in response to an applied voltage differential. The ceramic layer is sealed with a solid, low viscosity sealer, such as Carnauba wax, to protect the ceramic layer from moisture penetration.
Claims46
A charging roller for assisting in charging toner in a machine, the charging roller comprising:
- a cylindrical roller core;
- a ceramic layer disposed around the cylindrical roller core;
- wherein the ceramic layer is a plasma-sprayed blend of an insulating ceramic material and a semiconductive ceramic material;
- and
- wherein the insulating ceramic material and the semiconductive ceramic material are blended in a ratio to control an RC circuit time constant relating to the ceramic layer.
A charging roller for assisting in charging toner in a machine, the charging roller comprising:
- a cylindrical roller core;
- a ceramic layer disposed around the cylindrical roller core;
- wherein the ceramic layer includes an insulating ceramic material and a semiconductive ceramic material;
- and
- wherein the ceramic layer is formed by plasma spraying a blend of the insulating ceramic material and the semiconductive ceramic material to form the ceramic layer around the roller core, while controlling a selected RC circuit time constant for the ceramic layer.
Dependencies are inferred from the claim text.