Patent ID: 9563143
Date: 2017-02-07
CPC Classifications: G03G

Claim:
1. An image formation apparatus comprising: an image formation section including image formation units configured to form images on a medium; and a mechanism controller configured to control the image formation section and cause the image formation section to perform image formation, wherein the mechanism controller performs image formation misregistration amount detection processing that comprises causing each of the image formation units in the image formation section to form a first misregistration amount detection pattern, and computing a first image formation misregistration amount by comparing each of the first misregistration amount detection patterns formed by each of the image formation units that output a non-black color with one of the first misregistration amount detection patterns formed by one of the image formation units that outputs a black color, comparison processing that comprises comparing the first image formation misregistration amount with a previous image formation misregistration amount that is obtained and stored prior to obtaining the first image formation misregistration amount, and image formation misregistration correction processing that comprises, each time a door of the image formation apparatus has been opened when a print job is in progress and has not yet completed: (a) when a difference between the previous image formation misregistration amount and the first image formation misregistration amount is larger than a predetermined value, causing each of the image formation units to complete the print job that is in progress according to the previous image formation misregistration amount, and causing, after completion of the print job that is in progress and that is being printed according to the previous image formation misregistration amount, each of the image formation units in the image formation section to form a second misregistration amount detection pattern, and obtaining a second image formation misregistration amount based on a detection result obtained by detecting a reflection of the second misregistration amount detection pattern, and correcting the image formation misregistration according to the second image formation misregistration amount for future print jobs to be processed by the image formation apparatus after the print job that is in progress, and (b) when the difference between the previous image formation misregistration amount and the first image formation misregisration amount is not more than the predetermined value, correcting the image formation misregistration according to the first image formation misregistration amount.