Patent ID: 8724175

Claim:
A halftone correction device for use in an image forming apparatus that includes an intermediate transfer belt and performs a plurality of halftone processes, the halftone correction device comprising: a halftone correction unit configured to include a plurality of correction tables, each correction table corresponding to a respective one of the halftone processes, and perform halftone correction processing for each of the halftone processes using a corresponding one of the correction tables; a halftone pattern generation unit configured to generate, on the intermediate transfer belt, halftone patterns based on at least one of the halftone processes; an image density measurement unit configured to measure image densities of the halftone patterns generated on the intermediate transfer belt; a tone density estimation unit configured to estimate, from the image densities of the halftone patterns based on the at least one of the halftone processes, image densities of halftone patterns corresponding to the other ones of the halftone processes of the image forming apparatus, by applying a relational expression serving as an estimation equation to patches of the halftone patterns having an equal image area ratio; and a correction table generation unit configured to include correction target values, and generate the correction tables for the halftone processes using the correction target values and the image densities of the halftone patterns of the halftone processes.