(12) United States Patent ao) Patent No.: Us 7,460,145 B2
Amadaetal. (45) Date of Patent: Dec. 2,2008
(54) MULTI-BEAM PITCH ADJUSTING
APPARATUS AND IMAGE FORMING
(75) Inventors: TakuAmada, Yokohama (JP);
Kazuyuki Shimada, Chofu (JP)
(73) Assignee: Ricoh Company, Ltd., Tokyo (JP)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 70 days.
(21) Appl.No.: 11/691,181
(22) Filed: Mar. 26, 2007
(65) Prior Publication Data
US 2007/0189008 Al Aug. 16, 2007
Related U.S. Application Data
(62) Division of application No. 10/200,778, filed on Jul. 24, 2002, now Pat. No. 7,206,014.
A multi-beam scanning apparatus includes a light source having first and second light source sections that hold a pair of semi-conductor laser diodes and coupling lenses that couple four beams irradiated from the pair of semi-conductor laser diodes with a base member. A light beam deviating device may be provided so as to deviate the four beams. A scan imaging device is also provided so as to scan a scan receiving surface with beam spots of the beams deviated by the light beam deviating device. A beam pitch-detecting device is also provided so as to detect a beam pitch of the respective beams formed on the scan-receiving surface. A beam pitch correcting device is provided in order to correct the beam pitch by causing relative deviation of a light axis among the respective beams on a sub scanning direction cross sectional plane.
17 Claims, 32 Drawing Sheets