Patent ID: 9703246
Date: 2017-07-11
CPC Classifications: G03G,H04N

Claim:
1. An image forming apparatus, comprising: a printing device capable of printing at plural linear velocities; an image scanning device; a differential correction data generating unit configured to (a) cause the printing device to print a test chart at a reference linear velocity among the plural linear velocities and a test chart at another linear velocity among the plural linear velocities, (b) cause the image scanning device to scan images of the printed test charts, (c) measure a density characteristic at the reference linear velocity and a density characteristic at the another linear velocity on the basis of the scanning result of the images of the test charts, and (d) generate differential correction data on the basis of the density characteristic at the reference linear velocity and the density characteristic at the another linear velocity, the differential correction data being a difference between a correction amount for the density characteristic at the reference linear velocity and a correction amount for the density characteristic at the another linear velocity; a correction amount adjusting unit configured to (a) form an adjustment toner pattern at the reference linear velocity on an intermediate transfer member in the printing device, (b) measure a density of the adjustment toner pattern formed on the intermediate transfer member using a density sensor in the printing device and thereby measure a density characteristic at the reference linear velocity, and (c) adjust a correction amount for the density characteristic at the reference linear velocity on the basis of the measured density characteristic at the reference linear velocity; and a density characteristic correcting unit configured to (a) for printing at the reference linear velocity, perform correction of a density characteristic of a printing image on the basis of the correction amount at the reference linear velocity, and (b) for printing at the another linear velocity, perform correction of a density characteristic of a printing image on the basis of the correction amount at the reference linear velocity and the differential correction data.