Image forming apparatus, image forming method, and computer readable medium for identifying target-recording element using detection pattern

A non-transitory computer readable medium storing a program causing a computer to execute a process for forming an image, the process comprising:

• driving a plurality of recording elements arrayed in a first predetermined direction in accordance with input image information so as to form the image on a recording medium that moves relatively to the recording elements in a second direction orthogonal to the first direction;
• reading the formed image via an optical system and outputting read data;
• performing control 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
• identifying a target recording element on the basis of read data obtained by reading the detection pattern,
• extracting 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 each of the blocks are segmented 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
• identifying the recording elements corresponding to the patterns on the basis of the blocks and the rows.

An image forming method comprising:

• driving a plurality of recording elements arrayed in a first predetermined direction 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;
• reading the formed image via an optical system and outputting read data;
• performing control 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
• identifying a target recording element on the basis of read data obtained by reading the detection pattern,
• extracting 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 each of the blocks are segmented 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
• identifying the recording elements corresponding to the patterns on the basis of the blocks and the rows.