Patent ID: 8711441
Filing Date: 2014-04-29
Classification: B41J

Abstract:
1. An image forming apparatus comprising: an image forming unit that includes a plurality of recording elements arrayed in a first predetermined direction and drives the recording elements in accordance with input image information so as to form an image on a recording medium that moves relatively to the recording elements in a second direction orthogonal to the first direction; a reading unit that reads the image formed by the image forming unit via an optical system and outputs read data; a controller that controls the image forming unit so as to form a detection pattern in a detection-pattern region located upstream or downstream, in the second direction, of a region where the image according to the input image information is formed in the recording medium such that other images are not continuous with the detection pattern, the detection pattern including stepped patterns arranged such that ends thereof are aligned with each other in the first direction, the stepped patterns respectively corresponding to a plurality of groups of the recording elements obtained by dividing the plurality of recording elements arrayed in the first direction into groups that include the same number of successively-arrayed recording elements, the stepped patterns each including patterns having the same length and extending in the second direction, the patterns included in each stepped pattern respectively corresponding to the recording elements included in the corresponding group of the recording elements, the patterns being arranged such that front and rear ends of patterns corresponding to adjacent recording elements are connected to each other; and an identifying unit that identifies a target recording element on the basis of read data obtained by reading the detection pattern using the reading unit, the identifying unit extracts a pattern region where the detection pattern is formed from the read data obtained by reading the detection pattern and segments the pattern region into a plurality of blocks in the first direction so that each block has a width that corresponds to a width of each group of the recording elements, wherein the identifying unit segments each of the blocks into a plurality of rows in the second direction such that the number of rows corresponds to the number of recording elements included in each group, and wherein the identifying unit identifies the recording elements corresponding to the patterns on the basis of the blocks and the rows.