Rotary drive apparatus, optical scan apparatus, and image formation apparatus

摘要

A rotary drive apparatus includes a rotary body with a support portion, a rotor magnet supported by the support portion of the rotary body, a fixation section facing the rotor magnet and rotatably supporting the rotary body, and a winding coil provided in the fixation section, in which an expression E 1/ E 2 <=0.75 is satisfied where Young's modulus of the rotor magnet is E 1 [ GPa], and Young's modulus of the support portion is E 2 [ GPa].