| 摘要 |
PURPOSE:To make it possible to smoothly perform high speed printing even if pressure of a platen is made high, by providing a minute vibration imparting means to the platen contacted with a thermal head under pressure. CONSTITUTION:A platen 11 is formed by covering a shaft 12 with rubber 13 and minute vibration is applied to the shaft 12 of said platen 11 by an ultrasonic horn as shown by the arrow. To a platen 21 prepared by successively forming piezoelectric ceramic 23, a metal ring 22 and covering rubber 25 to the outer periphery of a metal shaft 22, high frequency voltage is applied by using the shaft 22 and the ring 24 as electrodes. Whereupon, the piezoelectric ceramic 23 is operated and minute vibration is applied to the platen 22. Because printing is performed while minute vibration is applied to the platen by a minute vibration applying means by ultrasonic vibration, piezoelectric vibration or magnetostriction vibration, rotary torque required in driving the platen may be small even if the pressure of the platen for pressing recording paper to a thermal head is made high. Therefore, high speed and high quality printing can be smoothly performed without impairing controllability by using a small drive source. |
