Developing apparatus having toner supply roller applied with bias voltage varied in accordance with changes in physical properties thereof
AssigneeKabushiki Kaisha Toshiba
InventorKouji Hirano
Life of this patent
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Abstract
A developing apparatus of a one-component developer system includes a developing roller and a toner supply roller for supplying a toner to the developing roller. Predetermined bias voltages are applied from bias power supplies to these rollers, respectively. The apparatus is designed such that the bias voltage applied to the toner supply roller is variably controlled in accordance with changes in physical properties of the toner supply roller, which are determined from the number of the printing cycles, a voltage at a surface of the supply roller or a toner density at leading and end portion of a strip-like image pattern formed on the image carrying drum.
Claims14
An image forming apparatus for forming a latent image on an image carrying member, comprising:
- a developing roller for forming a developer image corresponding to said latent image on said image carrying member;
- a developer supplying roller, at least a surface of which is constituted by a resilient member contacting with said developing roller for supplying the developer to said developing roller;
- image transfer means for transferring the developer image formed on said image carrying member to a medium on which a visual image is being formed;
- voltage applying means for applying to said developer supplying roller at least one of first and second bias voltages having a value for generating a predetermined voltage difference between said developing roller and said developer supplying roller, said second bias voltage having an absolute value larger than that of the first bias voltage;
- measuring means for measuring a surface potential of said developer supplying roller;
- and
- means for changing the first bias voltage applied by said voltage applying means to said second bias voltage to generate a predetermined potential difference between said developer supplying roller and said developing roller in accordance with a measuring result of said measuring means.
An image forming apparatus for forming a latent image on an image carrying member, comprising:
- a developing roller for forming a developer image corresponding to said latent image on said image carrying member;
- a developer supplying roller, at least a surface of which is constituted by a resilient member contacting with said developing roller for supplying the developer to said developing roller;
- image transfer means for transferring the developer image formed on said image carrying member to a medium on which a visual image is being formed;
- voltage applying means for applying to said developer supplying roller at least one of first and second bias voltages having a value for generating a predetermined voltage difference between said developing roller and said developer supplying roller, said second bias voltage having an absolute value larger than that of the first bias voltage;
- measuring means for measuring a developing density of the developer image formed on said image carrying member;
- and
- means for changing the first bias voltage applied by said voltage applying means to said second bias voltage to generate a predetermined potential difference between said developer supplying roller and said developing roller in accordance with a measuring result of said measuring means.
Dependencies are inferred from the claim text.