Patent ID: 7692814
Filing Date: 2010-04-06
Classification: G03G,H04N

Abstract:
1. An image forming apparatus, comprising an image processing means for determining a pixel gradation indicating gray level in each pixel based upon a prescribed image data, and an exposing means for writing an electrostatic latent image onto a photo receptor with an exposure amount corresponding to said pixel gradation determined by said image processing means by exposing each pixel on a surface of said photo receptor previously electrified by an electrification means, said image forming apparatus further comprising: an individual differential information memory means for individually memorizing for each segment multi-divided a surface of said photo receptor said differential information that corresponds to the difference between an initial electric potential of said segment and an reference initial electric potential common between all of said segments; and an exposure amount control means for controlling said exposure means to expose each of said segments with an exposure amount added with only an exposure amount corresponding to said differential information when said pixel gradation is within a prescribed range including 0 gradation level comparing an exposure amount obtained by approximately linear-transforming said pixel gradation determined by said image processing means into a exposure amount, and wherein controlling said exposure means for conducting the exposure equivalent to the exposure amount obtained by the approximate linear transformation of the pixel gradation into the exposure amount and the exposure equivalent to the exposure amount of additional exposure on the basis of the differential information can be conducted to each pixel at different separated time zone, and the exposure equivalent to the exposure amount added (offset) corresponding to the differential information can be conducted at the multiple-separated in each pixel.