Patent ID: 8253997
Filing Date: 2012-08-28
Classification: B41J

Abstract:
1. A correction information creation device comprising: a recording head in which a plurality of image formation elements are two-dimensionally arranged such that the image formation elements are not aligned in a sub-scanning direction, the image formation elements respectively forming dots that constitute an image at a predetermined surface synchronously with a clock signal; a rotating body that rotates with a peripheral surface thereof opposing the image formation elements, the rotating body functioning as one of a pulse generator that generates a pulse signal in accordance with rotation of the rotating body; a first detector that detects a period of the pulse signal; a first calculation section that calculates a period of the clock signal on the basis of a reference rotation angle of the rotating body at which the pulse signal is generated, a distance between neighboring dots, an ideal distance between the peripheral surface of the rotating body and an axial center of the rotating body, and the detected period of the pulse signal; a formation section that, while the rotating body is being rotated at a predetermined rotation speed, causes at least two sets of image formation elements of the plurality of image formation elements to sequentially form corrective images, which are used for correcting the period of the clock signal, at different positions of the peripheral surface, synchronously with a clock signal occurring at the period calculated by the first calculation section, wherein the at least two sets of image formation elements comprises a first set of image formation elements disposed at upstream side in a rotation direction of the rotating body, and a second set of image formation elements disposed at downstream side in the rotation direction, the at least two sets of image formation elements are separated from each other by a predetermined space in the rotation direction; a second detector that detects a space between the formed corrective images; a second calculation section that calculates a distance between a measurement position of the peripheral surface of the rotating body and the axial center of the rotating body on the basis of the detected space between the corrective images, a value obtained by multiplying the distance between the dots by a predetermined integer, the predetermined space, and the ideal distance between the peripheral surface of the rotating body and the axial center of the rotating body; and a memory section that stores distance information representing the distance calculated by the second calculation section, to serve as information for correcting the period of the clock signal, in association with a measurement rotation angle from a reference position of the rotating body to the measurement position.