| 摘要 |
PROBLEM TO BE SOLVED: To reproduce stable gradation by avoiding gradation number of printed-out image data from being decreased even in the case of making gamma correction. SOLUTION: A CPU of an engine 54 forms an image a plurality of correction patterns where gradation of a noted dot is gradually changed by write dot number around the noted dot in advance onto a recording medium as gradation patterns in different gradation number of a noted dot per unit length in turning directions from a low concentration part and a high concentration part, each density is detected by using an optical sensor and gamma correction data are generated, based on the detection result. Then a gamma correction section 52 references dots around the noted dot of image data applied with pseudo gradation processing from a printer controller 51 to discriminate the environment and any of the gamma correction data is selected depending on the discrimination result and the gamma correction data are used to correct the gradation of the noted dot of the image data to provide an output of a corresponding write level signal. |
