An information processing apparatus connected with an image forming apparatus including an image forming unit that includes:
- a first reception unit configured to receive image data;
- a light source configured to emit light according to the image data received by the first reception unit;
- a photosensitive member;
- a polygon mirror that has a plurality of reflection surfaces and deflects the light emitted from the light source by using the plurality of reflection surfaces to scan the photosensitive member by rotating:
- a light receiving unit configured to have a light receiving element that receives the light deflected by the polygon mirror;
- a specifying unit configured to specify a reflection surface used for scanning the photosensitive member among the plurality of reflection surfaces;
- a generation unit configured to generate a signal having a first level and a second level based on information about the reflection surfaces specified by the specifying unit, a period of the first level of the signal corresponding to a predetermined reflection surface among the plurality of reflection surfaces being longer than a period of the first level of the signal corresponding to the other reflection surfaces than the predetermined reflection surface,
- the information processing apparatus comprising:
- a second reception unit configured to receive the signal;
- a detection unit configured to detect a first timing at which the signal changes to the first level from the second level and a second timing at which the signal changes to the second level from the first level;
- a measurement unit configured to measure a period from the first timing detected by the detection unit to the second timing that is detected first after elapsing a first period from the first timing;
- an update unit configured to specify the reflection surface based on the period measured by the measurement unit and to update surface information about the reflection surfaces every time of receiving the signal after specifying the reflection surfaces;
- a storage unit configured to store a plurality of pieces of correction data that respectively correspond to a different one of the plurality of reflection surfaces in association with the surface information;
- a correction unit configured to correct the image data corresponding to the reflection surface according to the surface information and the correction data stored in the storage unit;
- and
- an output unit configured to output the image data corrected by the correction unit to the image forming unit in response to detection of the first timing,
- wherein the first period is shorter than a period from the first timing to the second timing corresponding to the predetermined reflection surface and is longer than a period from the first timing to the second timing corresponding to the other reflection surfaces.