| 摘要 |
PURPOSE:To enable reduction of load on an eccentric cam with the flexibility value of a coil spring which presses a printing head to a platen being set to a low level by mounting the printing head on a head support of which one end is axially attached to a housing. CONSTITUTION:If an eccentric cam 25 is set on a rotational position by a drive shaft 26, a head assembly 20 turns counter-clockwise around a rotational shaft 23, causing a printing head 5 to contact a platen 3. At that time, a head drive plate 22 is slightly pushed up by the eccentric cam 25, and instead a coil spring 24 shrinks by the amount of rising. Its repulsive force causes the printing head 5 to be pressed to the platen 3 via an ink ribbon R and printing paper P. A prearranged image is printed on printing paper by rotating the platen 3. When feeding without a load, the eccentric cam 25 is rotated 180 deg. via the drive shaft 26. As a result, the head assembly 20 turns clockwise and the printing head 5 is separated from the platen 3. Consequently the flexibility amount of the coil spring 24 is determined by the clearance between the eccentric cam 25 and leg piece 21a during printing. |
