Image forming apparatus

A horizontal sync detection unit for an image forming apparatus configured to form an electrostatic latent image on a surface of a photosensitive member with a laser beam scanning on the surface of the photosensitive member, the horizontal sync detection unit comprising:

• a generation unit configured to generate a high-speed clock and a low-speed clock mutually different in frequency;
• a first shift register unit configured to receive a detection signal according to the high-speed clock, wherein the detection signal indicates detection of the laser beam performing scanning in a main scanning direction according to the low-speed clock;
• and
• an output unit configured to receive a parallel output of the first shift register unit in synchronization with the low-speed clock and to output detection timing of the laser beam as a detection signal synchronized with the low-speed clock and a value corresponding to a shift number defined by the high-speed clock.

A laser driving unit for an image forming apparatus configured to form an electrostatic latent image on a surface of a photosensitive member with a laser beam scanning on the surface of the photosensitive member, the laser driving unit comprising:

• a generation unit configured to generate a high-speed clock and a low-speed clock mutually different in frequency;
• a bit shift unit configured to receive image data to be output and a bit shift value in synchronization with the low-speed clock, wherein the bit shift value defines a bit shift amount of the image data to be output according to a write timing wait time, wherein the write timing wait time represents a time required for the laser beam to travel from a position where a horizontal sync signal of the image forming apparatus is detected to an image writing start position on the surface of the photosensitive member, the bit shift unit being configured to perform bit shift processing on the image data to be output according to the received bit shift value and to output parallel data of the image data;
• and
• a second shift register unit configured to shift the image data received from the bit shift unit according to the high-speed clock and to output a laser driving signal with a delay corresponding to the number of clocks of the high-speed clock corresponding to the bit shift value from the low-speed clock.