Patent ID: 7852532
Filing Date: 2010-12-14
Classification: G03G,H04N

Abstract:
1. An image forming apparatus comprising: an outputting section to output a chart which comprises a gradation pattern in a low-density area, the gradation pattern including patches, each of the patches having a density; a reading section to read-in the density of each of the patches for obtaining an input-output characteristics; a calculating section to calculate an adjusting value to adjust the output in the low-density area of a low-density correction curve, wherein the low-density correction curve has output values corresponding only to input values of not greater than a half of maximum input value of a gradation correction curve; and an output adjusting section to conduct an adjustment of an output in the low-density area based on a the gradation correction curve for totally correcting gradation characteristics, and on the low-density correction curve including the adjusting value as a parameter, wherein the calculating section extracts, from the input-output characteristics, a referential input value corresponding to an input value where a color density starts to rise in a gradation of the low-density area, receives a target input value regarding the input value where the color density starts to rise, and calculates an offset value to adjust the output in the low-density area as the adjusting value, so as to satisfy a relation of: