| 摘要 |
PURPOSE:To easily control a moving speed of a scanner, by comparing a speed signal from a moving speed sensor with a signal set in advance for generating a signal corresponding to a scanning speed, and changing the voltage applied to an electromagnetic clutch. CONSTITUTION:A pulse signal of frequency corresponding to a desired speed of a moving scanning part is generated by a digital switch 18, also a pulse generated by a sensor 17 is counted by a counter 20, resetting it at every constant interval of time by a clock 19, and a difference of pulses of both the signals is outputted from a comparator 21. This signal is converted to an analog value by a D/A converter 22, by which voltage applied to an electromagnetic clutch 11 is controlled through an automatic voltage controller 23. In this way, attracting force by magnetic force of a clutch plate friction face of the clutch 11 can be controlled minutely, therefore, against a load variation which follows movement of the scanning system, its slip extent is adjusted, and a moving speed of the scanning system can be stabilized to a desired value. |
