Patent ID: 8077351
Filing Date: 2011-12-13
Classification: G03G

Abstract:
1. An image forming apparatus that forms a color image by overlapping a plurality of colors, comprising: a scanner configured to read a document and generates image data; an image processing unit configured to correct gradation of the image data using gradation correction data and generate a gradation image of the image data with gradation after correction; a plurality of photoconductors corresponding to the plurality of colors; a plurality of charging units configured to electrically charge the plurality of photoconductors with a predetermined charged potential; a plurality of exposure units configured to expose the plurality of photoconductors with a predetermined exposure amount; a plurality of development units configured to develop the plurality of photoconductors with a predetermined development potential; a developer included in each of the plurality of the development units; a transfer body onto which images corresponding respectively to the plurality of colors formed on the plurality of photoconductors are transferred; a plurality of transfer units configured to transfer the images corresponding respectively to the plurality of colors from the plurality of photoconductors onto the transfer body; a sensor configured to detect a density of an image formed on the transfer body; a density adjusting unit configured to form a predetermined density test pattern on the transfer body and adjust process parameters including more than or equal to two among the charged potential, the exposure amount, the development potential, and a toner concentration of the developer such that a density of the density test pattern on the transfer body detected by the sensor falls within a predetermined range of a reference density; and a gradation adjusting unit configured to form a gradation test pattern having a plurality of gradation levels on the transfer body and update the gradation correction data such that a density for every gradation of the gradation test pattern on the transfer body detected by the sensor falls within a predetermined range of a reference gradation density acquired and stored beforehand, wherein the gradation adjusting unit updates the gradation correction data subsequently after the density adjusting unit adjusts the density of the density test pattern.