Patent ID: 8362816

Claim:
An image forming apparatus comprising: a recording unit configured to record image data on a recording medium; a first spread spectrum clock generator configured to receive a first clock signal, provide the first clock signal with frequency diffusion to have a first predetermined frequency diffusion width, and output a second clock signal which is provided with the frequency diffusion; a PLL circuit configured to receive the first clock signal and output a third clock signal synchronously oscillating at a frequency obtained by multiplying the frequency of the first clock signal; an image processing unit configured to receive the third clock signal, process the image data, and output the processed image data in synchronism with the third clock signal; a speed conversion unit configured to receive the second and third clock signals, receive the processed image data in synchronism with the third clock signal, and output the processed image data in synchronism with the second clock signal; an input and output control unit configured to receive the image data output from the speed conversion unit and the second clock signal, and output the image data to the recording unit in synchronism with the second clock signal; and a second spread spectrum clock generator configured to receive the first clock signal, provide the first clock signal with frequency diffusion to have a second predetermined frequency diffusion width, and output a fourth clock signal which is provided with the frequency diffusion; wherein the PLL circuit receives the fourth clock signal and outputs a fifth clock signal synchronously oscillating at a frequency obtained by multiplying the frequency of the fourth clock signal, the image processing unit receives the fifth clock signal and outputs the processed image data in synchronism with the fifth clock signal, and the speed conversion unit receives the second and fifth clock signals, receives the processed image data in synchronism with the fifth clock signal, and outputs the processed image data in synchronism with the second clock signal.