Image forming apparatus

An image forming apparatus comprising:

• a photosensitive member;
• a light source configured to emit a laser beam based on input image data;
• a deflecting unit configured to deflect the laser beam emitted from the light source so that the photosensitive member is scanned with the laser beam;
• a detecting unit configured to detect the laser beam deflected by the deflecting unit and to output a detection signal according to the detection of the laser beam;
• a storage unit configured to store the detection signal in synchronization with a first clock signal and to output a bit pattern of a plurality of bits corresponding to the stored detection signal in synchronization with a second clock signal having a frequency higher than a frequency of the detection signal and lower than a frequency of the first clock signal;
• an outputting unit configured to output a timing signal based on the bit pattern output from the storage unit and to output a phase signal corresponding to a change position of the bit data in the bit pattern;
• and
• a control unit configured to control, based on the timing signal and the phase signal output from the outputting unit, timing to emit the laser beam from the light source based on the input image data.

An image forming apparatus comprising:

• a photosensitive member;
• a light source configured to emit a laser beam based on input image data;
• a deflecting unit configured to deflect the laser beam emitted from the light source so that the photosensitive member is scanned with the laser beam;
• a detecting unit configured to detect the laser beam deflected by the deflecting unit and to output a detection signal according to the detection of the laser beam;
• a signal generating unit configured to generate a first clock signal having a frequency higher than a frequency of the detection signal output by the detecting unit and a second clock signal having a frequency lower than the frequency of the first clock signal and higher than the frequency of the detection signal;
• a determine unit configured to sample the detection signal in synchronization with the second clock signal and to determine a phase difference between the sampled detection signal and the second clock signal based on the first clock signal;
• and
• a control unit configured to control, based on the detection signal sampled in synchronization with the second clock signal by the determine unit and the phase difference between the detection signal and the second clock signal determined by the determine unit, timing to emit the laser beam from the light source based on the input image data.