| 摘要 |
PURPOSE:To obtain a printing head which can obtain a constant printing density irrespective of changes in thickness of a printing paper, by a method wherein a printing pin is driven through jetting of compressed air. CONSTITUTION:The end of a plate spring 2 is securedly supported on a frame 7 of a printing head through the aid of a screw 8. A printing pin 3 is fastened on the end of the open side of the plate spring so that it is positioned facing and opposite to a printing surface 4. When an air pressure in a nozzle 9 is lower than an atmospheric pressure, the plate spring is adhered firmly to the frame. If the air pressure in the nozzle becomes higher than an atmospheric pressure resulting from feeding of air into the nozzle, the plate spring is bent as shown in a broken line, and conducts a printing action. Through the adjustment of the air pressure, a printing force can be changed. Because a printing action is not done by an electrical means, it eliminates the possibility of ignition explosion even in an ignitable gas atmosphere, and thereby the device can be used in and safe from said atmosphere. |
