| 摘要 |
PURPOSE:To obtain the stable running movement of a medium, by driving a DC motor with output voltage of a position voltage generating means and output of a differential speed voltage generating means. CONSTITUTION:A rotary speed detecting circuit 12, for generating a signal of frequency in proportion to the rotary speed of a DC motor 5, and a phase lock loop (PLL) circuit 13, for generating voltage V2 in proportion to a level where an output frequency of the rotary speed detecting circuit 12 is substracted from the output frequency of a position oscillator 10, are provided. When looseness of a paper form 1 is decreased, a buffer 6 is shifted to positions A1, A2 to lower voltage V1 from a position voltage generating circuit 9, also output frequency (f) of the position oscillator 10 and also output voltage V2 of the PLL circuit 13, then the buffer 6 is controlled in such a manner as to return to a position C toward a direction where rotary speed of the DC motor 5 is decreased. While when the looseness of the paper form 1 is increased, control shall be made in such a manner that the buffer 6 is shifted to positions B1, B2 to raise both of the voltages V1, V2, then returned to the position C. |
