| 摘要 |
PURPOSE:To contrive satisfactory prevention of a ghost problem, by fitting a driving device for driving a roller main body in the axial direction to a shaft core so as not to hinder rotation of the roller main body, incorporating in the shaft core a power transmitting means for transmitting motive power from the exterior to the driving device, and firmly supporting the shaft core on a main body of a printing press. CONSTITUTION:A roller main body 13 is formed from a steel pipe having a diameter large than that of a shaft core 12, and a cylindrical ferrite permanent magnet 36 is fitted to a cylindrical inner wall of the roller main body opposed to a solenoid coil 34 on the shaft core 12. A play gap is provided between the solenoid coil 34 and the permanent magnet 36, so that rotation of the roller main body 13 is not hindered. Wires 14 disposed in the shaft core are used as a power transmitting means for the solenoid coil 34, and a magnetic field is generated under the control of a computer through the wires. The shaft core 12 is firmly fitted to a main body of an offset press, and when the direction of the magnetic field generated by the solenoid coil 34 is reversed, the roller main body 13 is driven leftward or rightward in the axial direction by an attracting or repelling force thus generated. |
