Patent ID: 7766443
Filing Date: 2010-08-03
Classification: B41J

Abstract:
1. A method of compensating for an error of a conveyance distance of a recording medium in an image forming apparatus, the image forming apparatus including: a feeding roller rotatably disposed to convey the recording medium in a conveying direction, the feeding roller including a rotational axle that is eccentric and a peripheral surface having an actual entire peripheral length that is different from a theoretical entire peripheral length; and a recording unit having a head length over which an image can be printed in the conveying direction, the head length being longer than the theoretical entire peripheral length, the method comprising: rotating the feeding roller one turn or N turns, N being a positive integer greater than 1; printing a plurality of second images on the recording medium before and after the feeding roller has been rotated said one turn or N turns, on the recording medium, a first image being printed in advance showing a reference distance corresponding to a distance equal to or N times the theoretical entire peripheral length; determining a difference of the actual entire peripheral length from the theoretical entire peripheral length based on both the first image and the plurality of second images; and adjusting, based on the difference of the actual entire peripheral length from the theoretical entire peripheral length, a rotational amount of the feeding roller.