Methods and apparatus for adjusting the amount of current provided to a magnetic actuator to compensate for a temperature change associated with the magnetic actuator are disclosed. The soldermask layer has two sets of openings. The first, second, and third surfaces have first, second, and third surface areas, respectively. A nut is fixed to the sleeve end wall, threadedly mounted on the shaft, and disposed around the central opening. When a control section determines that acceleration conditions are fulfilled, the driving section increases the rotating speed of the paper discharge unit-side gear so that it is rotated at higher speed than before-acceleration speed over predetermined high-speed rotating period. In accordance with the invention, the damping device includes a damping chamber formed on the return side, that is subjected to the system pressure acting on a pressure port.