Patent ID: 6493019
Filing Date: 2002-12-10
Classification: H04N

Abstract:
An image forming apparatus, comprising:an image forming unit including an image bearing member, beam generating means for generating a plurality of light beams and an optical scan system for scanning the image bearing member with the plurality of light beams generated by said beam generating means to write an image; beam detecting means for detecting the plurality of light beams scanning the image bearing member at predetermined positions and obtaining a plurality of beam detection signals; clock generating means for generating a single clock signal; control means for controlling the frequency of the single clock signal by controlling said clock generating means; and synchronization means for controlling the phase of the single clock signal generated by said clock generating means in accordance with the plurality of beam detection signals obtained by said beam detecting means, and generating a plurality of control clocks, wherein said beam generating means generates the plurality of light beams in accordance with the plurality of control clocks, and wherein said clock generating means includes a reference oscillator and PLL circuit to which an output of said reference oscillator is input.