Patent ID: 8843050

Claim:
An image forming apparatus comprising: an image forming unit including an image bearer on which images are formed and a development device to develop the image formed on the image bearer; a first rotary shaft; a second rotary shaft; a drive unit to drive the first and second rotary shafts and including a drive source to rotate at a predetermined low velocity and a predetermined high velocity, a first rotary transmitter connected between the drive source and the first rotary shaft to transmit the drive force to the first rotary shaft, a second rotary transmitter connected between the drive source and the second rotary shaft to transmit the drive force to the second rotary shaft, and a drive block member connected between the drive source and the second rotary shaft, to block transmission of the drive force to the second rotary shaft when the drive source rotates at the predetermined high velocity, wherein, when the drive source rotates at the predetermined low velocity, the drive unit drives the second rotary shaft using a difference in torque of the drive source between an upper limit torque in high velocity rotation and an upper limit torque in low velocity rotation, greater than the upper limit torque in high velocity rotation.