An image forming apparatus, which is operable at a plurality of image forming speeds, comprising:
- a photosensitive member;
- a light source configured to emit a light beam;
- a deflection unit configured to deflect the light beam emitted from the light source so that the light beam scans on a surface of the photosensitive member in a main scanning direction;
- a developing unit configured to develop, with a toner, an electrostatic latent image, which is formed on the surface of the photosensitive member by the light beam, into a toner image;
- a transfer unit configured to transfer the toner image from the surface of the photosensitive member onto a bearing member or a recording medium that is conveyed by the bearing member;
- a pattern detection unit configured to detect a registration correction pattern, which is transferred onto the bearing member by the transfer unit;
- and
- a processor and a memory configured to function as:
- a writing start timing determination unit configured to determine writing start timing at which the electrostatic latent image is started to be written on the photosensitive member by the light beam emitted from the light source, based on a detection result of the pattern detection unit;
- a storage unit configured to store a correction amount for correcting the writing start timing that is determined by the writing start timing determination unit;
- a density detection unit configured to detect a density correction pattern, which is transferred onto the bearing member by the transfer unit;
- and
- a light intensity setting unit configured to set a light intensity of the light beam that is emitted from the light source, based on a detection result of the density detection unit,
- wherein, in a case where a previous image forming speed when the registration correction pattern is detected by the pattern detection unit is the same as a next image forming speed at which a next image is formed, the next image is formed at the writing start timing that is determined by the writing start timing determination unit at the previous image forming speed, and
- wherein, in a case where the previous image forming speed differs from the next image forming speed, the correction amount is corrected based on a difference between a light intensity of the light beam when the registration correction pattern is formed and a light intensity of the light beam when the next image is formed, the writing start timing that is determined by the writing start timing determination unit at the previous image forming speed is corrected based on a corrected correction amount and on a speed ratio of the previous image forming speed to the next image forming speed, and the next image is formed based on a corrected writing start timing.