| 摘要 |
PROBLEM TO BE SOLVED: To saturate a soaring temperature within the tolerance limits of a routine operating mode, even if the operation is performed in a high speed operating mode by changing the ON/OFF time ratio of a drive current in accordance with a rise in the temperature of a linear motor, and controlling the rise in the temperature of the linear motor to the set tolerance limits through the setting of an upper limit value for the ON time ratio of the drive current. SOLUTION: The shuttle operation is such that a linear motor is activated by an essential current i0 decided by initialization. After this step, a current valueαis increased or decreased in accordance with a change in the thrust F generated at the time of accelerating or decelerating the rotating speed of the linear motor. In this case, the increase of the current valueαis stopped at the point of time when the increase reaches a value I exceeding the tolerance value of a temperature rise so that the increase is not continued beyond the threshold of the value I. That is, the upper limits are set to the ON/OFF ratio of a transistor. The upper limits value should be the value not higher than the permissible temperature range of a material used for the linear motor and at which the lowest permissible printing speed is ensured. The upper limits value is previously depicted by experiments using the linear motor to be used.
|
