Scanning device and image forming apparatus

An image forming apparatus comprising:

• a photosensitive member having an electrostatic latent image to be formed thereon;
• a scanning device configured to form the electrostatic latent image on the photosensitive member, wherein the scanning device comprises:
• a light source configured to emit a light beam;
• a deflecting unit configured to deflect and scan the light beam emitted from the light source;
• a driving unit configured to drive the deflecting unit to scan the light beam in a full-scanning region;
• a generating unit disposed in a second region of the full-scanning region, wherein the second region is excluding a first region on which the light beam based on image data is scanned, and the generating unit is configured to generate a signal in response to reception of the light beam;
• and
• a control unit configured to control a first light emission state and a second light emission state in an activation period from start of activation of the driving unit to when the number of rotations of the driving unit reaches a target number of rotations, the control unit controlling the light source to emit light such that the light beam scans the first region and the second region in the first light emission state and controlling the light source to emit light such that the light beam scans the second region,
• wherein the control unit acquires cycles of the signals generated by the generating unit, determines a timing for changing from the first light emission state to the second light emission state on the basis of the cycles of two serial signals, and changes the light source from the first light emission state to the second light emission state according to the timing;
• a developing unit configured to develop the electrostatic latent image formed on the photosensitive member by using toner to form a toner image;
• and
• a transfer unit configured to transfer the toner image formed by the developing unit on the photosensitive member to a recording material.