Patent ID: 6879334
Filing Date: 2005-04-12
Classification: H04N

Abstract:
1. An image forming apparatus configured to shift a scanning position on a surface scanned of each of a plurality of optical beams in a main scanning direction and a sub-scanning direction, and to scan a plurality of lines simultaneously in the main scanning direction by a deflecting part, comprising: a synchronization detecting sensor configured to detect the plurality of optical beams; a counter configured to count a clock having a higher frequency than a dot clock in an interval between a synchronization detection point of a first beam and a synchronization detection point of a second beam, said first and second beams included in the plurality of optical beams detected by said synchronization detecting sensor, and to divide a counted value into first information that indicates a number of the dot clocks and second information that indicates a number of the clocks; a determining part configured to determine a starting position of writing for each of the plurality of optical beams based on the counted value counted by said counter and including a first delaying part and a second delaying part, the first delaying part configured to delay the starting position of writing of each of the plurality of optical beams in units of the dot clocks based on the first information, and the second delaying part configured to delay the starting position of writing in units of the clocks having the higher frequency than the dot clock based on the second information; and a writing part configured to write each dot from the starting position of writing of each of the plurality of optical beams determined by said determining part, according to the clock having the higher frequency than the dot clock.