| 摘要 |
<p>PURPOSE:To prevent the occurrence of troubles due to the shift of timing, by locking a head base temporarily when the head base advances for a prescribed length and releasing the lock to advance the head base rapidly when a moving member goes for a prescribed length or more. CONSTITUTION:A head base 27 is driven through a head base advancing arm 109, which is supported pivotally through a pivot pin 111, and a head base detaining arm 105, which is engaged with this arm 109, by a head base driving lever 98. In this constitution, when the driving lever 98 moves right to advance the head base 27, a pin 108 is brought into contact with a detaining pawl 115 of the arm 105 to lock the head base 27 temporarily; and when the lever 98 moves furthermore, the lock is released. At this time, since a spring 100 is stretched out, the lever 98 moves right rapidly by the restoring force, and the head base 27 advances rapidly also. Thus, the occurrence of troubles due to the shift of timing is prevented.</p> |
