Electrophotographic image forming apparatus which controls developer bias based on image irregularity
First Claim
1. An image forming apparatus comprising:
- an image carrier;
latent image forming means for electrostatically forming a latent image on said image carrier;
developing means for conveying a two-component type developer made up of a toner and a carrier to a developing region where a developer carrier faces said image carrier and transfers said developer to said image carrier, and forming a bias electric field for development having an alternating electric field in said developing region to convert said latent image to a toner image;
reference latent image forming means for forming a predetermined reference latent image on said image carrier;
irregularity detecting means for detecting, after said developing means has developed said reference latent image to produce a reference toner image, a degree of difference in density between an edge and a central portion of said reference toner image; and
bias electric field control means for controlling said bias electric field in response to an output of said irregularity detecting means.
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Accused Products
Abstract
An image forming apparatus having a developing device of the type using a two-component type developer and developing an electrostatic latent image by a bias electric field having an alternating electric field. A predetermined reference latent image is electrostatically formed on an image carrier by a reference latent image forming device and then developed by the developing device to become a reference toner image. An irregularity detecting circuit determines the degree of difference between the density of the edge and the density of the central portion of the reference toner image. A bias electric field control circuit controls the bias electric field in matching relation to the output of the irregularity detecting circuit, thereby preventing the image quality from being degraded by a change in the resistance of the carrier.
63 Citations
18 Claims
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1. An image forming apparatus comprising:
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an image carrier; latent image forming means for electrostatically forming a latent image on said image carrier; developing means for conveying a two-component type developer made up of a toner and a carrier to a developing region where a developer carrier faces said image carrier and transfers said developer to said image carrier, and forming a bias electric field for development having an alternating electric field in said developing region to convert said latent image to a toner image; reference latent image forming means for forming a predetermined reference latent image on said image carrier; irregularity detecting means for detecting, after said developing means has developed said reference latent image to produce a reference toner image, a degree of difference in density between an edge and a central portion of said reference toner image; and bias electric field control means for controlling said bias electric field in response to an output of said irregularity detecting means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An image forming apparatus comprising:
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an image carrier; latent image forming means for electrostatically forming a latent image on said image carrier; developing means for conveying a two-component type developer made up of a toner and a carrier to a developing region where a developer carrier faces said image carrier and transfers said developer to said image carrier, and forming a bias electric field for development having an alternating electric field in said developing region to convert said latent image to a toner image; reference latent image forming means for forming a predetermined reference latent image on said image carrier; reference toner image detecting means for detecting the size of a reference toner image which said developing means has produced by developing said reference latent image; and bias electric field control means for controlling the bias electric field in response to said reference toner image detecting means. - View Dependent Claims (16)
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17. An image forming apparatus comprising:
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an image carrier; latent image forming means for electrostatically forming a latent image on said image carrier; developing means for conveying a two-component type developer made up of a toner and a carrier to a developing region where a developer carrier faces said image carrier and transfers said developer to said image carrier, and forming a bias electric field for development having an alternating electric field to convert said latent image to a toner image; deterioration detecting means for detecting a degree of deterioration of said developer; and bias electric field control means for controlling the frequency of the bias electric field in response to said deterioration detecting means. - View Dependent Claims (18)
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Specification