| 摘要 |
PURPOSE:To change the shifting pitch of a head by changing over the relation of locking to any of a ratchet turning means and plural pressing pieces. CONSTITUTION:Since the turning angle of a ratchet turning means 151 is increased more by engaging a pressing piece 131 having a relatively longer turning radius to the ratchet turning means 151 thereby increasing the amount of turning of a ratchet gear 143, the amount of movement of a head support member, that is, the head shifting pitch is increased. Moreover, since the turning angle of the ratchet turning means 151 is decreased further by engaging a pressing piece 125 having a relatively shorter turning radius to the ratchet turning means 151 thereby decreasing the amount of turning of the ratchet gear 143, the head shifting pitch is reduced. Thus, the head is moved for each prescribed different pitch with high accuracy by having only to set the turning radius of each pressing piece in matching with the turning angle of the rachet gear required for moving a prescribed pitch. |
