Patent ID: 7315320

Claim:
An optical writing system comprising: at least two laser diodes; a polygonal mirror; a first correction mechanism configured to receive a first external parameter, scan data of two laser diodes by one scanning movement with said polygonal mirror, and correct, based on the first external parameter, a dot forming position of a terminating edge in a main scanning direction by shifting arbitrarily a phase of a picture element clock; and a second correction mechanism configured to receive a second external parameter, and correct, based on the second external parameter, an amount of deviation in a data writing position along a vertical scanning direction to be approximately one laser diode line width, wherein said second correction mechanism is further configured to receive the second external parameter that includes information indicating that a type of a document is one of a character document, a photography document, a mixed character and photography document, and a non-character and non-photography document, and said second correction mechanism is further configured to enable correction of an amount of deviation in a data writing position in accordance with a first difficulty level when the information indicates that the type of document is a character document.