| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology for highly accurately controlling gradation correction characteristics, in an image forming apparatus and an image forming method which control the gradation correction characteristics based upon the result of the detection of patch image density. <P>SOLUTION: For patch images formed by gradually changing a gradation level, density sampling is conducted while changing a sampling position. Image density (evaluation value) G1(x) in each position is thereby obtained. In order to prevent the influence of cyclically nonuniform density caused by the eccentricity of a development roller or variations in characteristics, a moving averaging processing is performed using evaluation value data G1(x1-5) to G1(x1+5) included in a range to be processed, which corresponds to the circumferential length Ldr of a development roller. Then, an evaluation value G2(x1) after the correction is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
