Patent ID: 7460279
Filing Date: 2008-12-02
Classification: H04N

Abstract:
1. An adjustment method conducted in an image reading device including a first carrying part configured to carry a sheet inserted from a sheet inlet to a reading part, a plurality of reading parts including one or more first reading parts arranged along one line at an upstream and one or more second reading parts arranged along another line at a downstream in a longitudinal direction of the plurality of reading parts in a main direction for reading the sheet being carried by the first carrying part, wherein the plurality of reading parts are alternatively arranged to be one of the one or more first reading parts and the one or more second reading parts in order to form a staggered formation so that a start pixel and an end pixel to read image data are overlapped at joints between the one or more first reading parts and the one or more second reading parts, and a combining part configured to delay image data read by the one or more first reading parts of the plurality of reading parts arranged to be staggered, and to combine image data read by the one or more first reading parts and the one or more second reading parts, and a second carrying part configured to carry the sheet toward a direction opposite to the sheet inlet, said adjustment method comprising: determining a reference interval between two parallel lines in a main scanning direction, the two parallel lines extending along a sub-scanning direction and being shown as a parallel line pattern; calculating each parallel line image interval between two parallel line images shown in each of parallel line pattern images obtained by reading the sheet so that each joint of the one or more first reading parts and the one or more second reading parts is placed between the two parallel line images; comparing the reference interval in the main scanning direction with the parallel line image interval; determining the start pixel and the end pixel to read the image data at each joint of the one or more first reading parts and the one or more second reading parts by obtaining an interval difference between the reference interval and the parallel line image interval for the each joint so as to adjust the plurality of reading parts; comparing a reference straight line extending along the main scanning direction with each of a plurality of straight line images extending along the main scanning direction at each joint of the one or more first reading parts and the one or more second reading parts, the plurality of straight line images obtained by causing the plurality of reading parts to read the sheet; obtaining an average value of relative displacement amounts by calculating displacement amounts of the plurality of straight line images in the sub-scanning direction and by calculating an arithmetic average of the displacement amounts; determining the average value of the relative displacement amounts as a delay amount of the image data read by the one or more first reading parts; and adjusting a delay time for the one or more first reading parts, the delay time being used by the combining part.