Patent ID: 8678537

Claim:
A feed control apparatus comprising: a feed roller that feeds a medium; a first detection unit that detects a rotational position of the feed roller; a two-dimensional sensor that detects, in two dimensions, plural marks when a test chart is fed by the feed roller, the plural marks being arranged on the test chart to represent predetermined points, the test chart being provided for adjusting feeding amounts of the feed roller; a control section having a processor configured to, determine, in relation to an actual position of a first mark of the plural marks read by the two dimensional sensor, an actual position in a main scanning direction and in a sub-scanning direction of a second mark of the plural marks read by the two-dimensional sensor after the feed roller rotates one revolution subsequent to when the first mark is read, determine a theoretical position of the second mark in the sub-scanning direction based on a known distance in the sub-scanning direction between the first mark and the second mark, determine a skew angle of the test chart based on the actual position of the second mark in relation to the actual position of the first mark and the theoretical position of the second mark in the sub-scanning direction, correct a skew angle component from the actual position of the second mark based on the determined skew angle to produce a skewless actual position of the second mark in the sub-scanning direction, determine an error between the skewless actual position of the second mark in the sub-scanning direction and the theoretical position of the second mark in the sub-scanning, determine a rotational position of a deformity in the feed roller based on the determined error, and control a rotational speed of the feed roller based on the determined rotational position of the deformity and the determined error.