Image forming apparatus

An image forming apparatus which forms an image by forming an electrostatic latent image on a photosensitive member with a laser beam, developing the electrostatic latent image with a developer to obtain a developer image, and transferring the developer image to a recording medium, the image forming apparatus comprising:

• a light source which outputs the laser beam for exposing the photosensitive member;
• a clock generating portion which generates a multiplied clock having a multiplied frequency that is obtained by multiplying a reference frequency of a reference clock;
• a pulse-width modulating circuit which outputs a pulse-width-modulated signal based on image data and the multiplied clock in order to drive the light source;
• and
• a control portion which obtains image data to be input to the pulse-width modulating circuit and, when it is unnecessary to output the pulse-width-modulated signal based on the obtained image data, controls the clock generating portion in such a manner that the clock generating portion does not generate a multiplied clock by multiplying the reference frequency of the reference clock.