| 摘要 |
PROBLEM TO BE SOLVED: To improve the precision of gradation correction in an image-forming device for forming a toner image half-toned by an error diffusion method. SOLUTION: Reference patterns P1-P3 having different dot patterns are formed on an intermediate transfer belt (S1), and the density of a portion (patch) corresponding to each gradation value of respective reference patterns P1-P3 is detected for sampling (S2). Then, the average value of three density values sampled corresponding to each gradation value is obtained (step S3), and gradation characteristics, which show the relationship between input image data and the density of an output image from the average density, are obtained. Aγcurve for correcting so that the gradation characteristics become linear is obtained (step S4), and the gradation of the input image data is corrected, based on theγcurve, thus forming an image having excellent gradation reproducibility. COPYRIGHT: (C)2007,JPO&INPIT
|
