| 摘要 |
PURPOSE:To detect the presence or absence of a paper, by providing a platen comprising a conductive part at an outer peripheral part thereof, disposing a paper guide plate formed of a conductive material in contact with with the outer peripheral part of the platen, connecting a paper-detecting circuit to the platen and the guide plate, and detecting the presence or absence of conduction between the platen and the guide plate. CONSTITUTION:A platen 5 is formed of a conductive rubber, so that the entire body of the platen 5 is conductive, and there is conduction between the platen 5 and a platen shaft 51 made of a metal. When a paper 7 is not inserted and a paper guide plate 9 is in contact with the platen 6, a conductive path extends through a lead wire 11, a conductive plate 6, the platen shaft 51, the platen 5, the paper guide plate 9 and a lead wire 12 to a paper-detecting circuit 13, so that the resistance of the assembly as evaluated from the circuit side is low. On the other hand, when the paper 7 is inserted into a guide passage 8 and is passed between the paper guide plate 9 and the platen 5, the conduction between the platen 5 and the guide plate 9 is interrupted by the paper 7, so that the resistance of the assembly as evaluated from the circuit side is high. The presence or absence of the paper is judged by reading changes in the resistance by the paper detecting circuit 13. |
