Image forming apparatus that reduces conveyance failure of sheet based on motor torque variation

An image forming apparatus comprising:

• at least one conveyance roller pair that includes a conveyance roller and a facing roller, the conveyance roller being rotationally driven at a predetermined rotation speed to convey sheets, the facing roller that forms a nip portion with the conveyance roller through which the sheets pass;
• an image forming unit that forms images on the sheets conveyed by the conveyance roller pair;
• at least one brushless motor that outputs a rotation speed signal, the brushless motor generating a rotary drive power that rotationally drives the conveyance roller;
• a motor drive control unit that outputs an input signal corresponding to the rotation speed of the conveyance roller to the brushless motor to control the brushless motor;
• a delay amount detector that detects a rotation delay amount of the brushless motor from the input signal and the rotation speed signal;
• and
• an image formation control unit that controls the image forming unit so as to form predetermined images, the image formation control unit controlling the motor drive control unit to convey the sheets at a predetermined timing toward the image forming unit,
• wherein the image formation control unit, during a continuous image formation in which a plurality of sheets are continuously conveyed by the conveyance roller pair with a predetermined sheet spacing and images are sequentially formed on the respective sheets, controls the motor drive control unit to sequentially perform an on and off control of the brushless motor corresponding to the respective sheets, and adjusts the sheet spacing and a rise time in the on control of the brushless motor corresponding to the rotation delay amount detected by the delay amount detector.