| 摘要 |
PROBLEM TO BE SOLVED: To reduce overshoot until the number of revolution becomes a specified value and stable, by outputting a decelerating pulse in addition to an accelerating pulse, in accordance with the deviation of the number of revolution of a scanner motor from a specified one, in a region where the number of revolution of the scanner motor is lower than the specified one. SOLUTION: Overshoot is reduced by a method of starting a scanner motor 104 with set count values of a first counter 209 and a second counter 210 made larger than that corresponding to a specified number of revolution, and with a target number of revolution lower than the specified number of revolution, and returning the set values to those at normally revolving time when the number of revolution reaches a switching number of revolution just before the specified one. And overshoot is reduced, and the number of revolution of the scanner motor 104 is converged to the specified one, by starting the scanner motor 104 with set values of the first counter 209 and the second counter 210 set to a value X1 larger than a revolving value X at specified time, and changing the count value over to X at the point of time when its number of revolution becomes N1 just before a normal number of revolution. |
