Image forming apparatus

An image forming apparatus comprising:

• a conveying unit, adapted to convey a sheet;
• an image forming unit, adapted to form an image;
• a first transferring unit, adapted to transfer the image formed by said image forming unit on an image bearing body;
• a second transferring unit, adapted to transfer the image on the image bearing body on the sheet conveyed by said conveying unit;
• a driving unit, adapted to drive the image bearing body;
• a reader, arranged to read the image on a surface of the image bearing body;
• a speed detector, arranged to detect a speed of the image bearing body on a basis of the image read by said reader;
• and
• a controller, to control said driving unit on a basis of the speed detected by said speed detector.

A speed detection device for an image processing apparatus comprising:

• an illuminating unit, arranged to irradiate a moving object;
• a reader, arranged to read a shadow image of ragged surface of the moving object, by receiving reflected light from the moving object;
• and
• a speed detector, arranged to detect a speed of the moving object on a basis of the shadow image read by said reader.

A speed detection device for an image processing apparatus comprising:

• an input unit, adapted to input a shadow image of ragged surface of a moving object, from a receiver receiving reflected light from the moving object illuminated by an illuminator;
• a sampling unit adapted to sample the shadow image input from the receiver;
• a comparing unit adapted to compare the shadow images sampled by said sampling unit;
• and
• a speed detector, arranged to detect a speed of the moving object on a basis of the comparison result.

A computer program for executing a speed detection method for an image processing apparatus, the speed detection method comprising the steps of:

• inputting a shadow image of a ragged surface of a moving object, from an image reader reading the shadow image by receiving reflected light from the moving object;
• sampling the shadow image read in said inputting step periodically;
• storing the shadow image sampled in said sampling step;
• comparing the shadow image sampled image in said sampling step and the shadow image stored in said storing step;
• and
• calculating the speed of the moving object on a basis of comparison result obtained in said comparing step.