Patent ID: 8346131

Claim:
An image forming apparatus, comprising: a rotary member rotatably arranged in the image forming apparatus; and a power transmission device coupled to the rotary member, the power transmission device being configured to receive a rotary force from a rotary force source and to transmit the received rotary force to the rotary member in a non-contact manner, the power transmission device including: a first rotary body to rotate by the rotary force and including N-pole magnets and S-pole magnets, each N-pole magnet and each S-pole magnet arranged alternately with each other on an outer circumferential surface of the first rotary body in a circumferential direction of the first rotary body; and a second rotary body spaced apart from the first rotary body and including N-pole magnets and S-pole magnets, each N-pole magnet and each S-pole magnet arranged alternately with each other on an outer circumferential surface of the second rotary body in a circumferential direction of the second rotary body.