| 摘要 |
PURPOSE:To ensure that a printing surface of a thermal recording paper is constantly maintained in parallel to a serial thermal head and pressed with a uniform pressure, by a construction wherein a rotary shaft of a platen can be turned relatively to a platen support around the same axis as that for a serial thermal head and with the same radius as that for the head so that the head and the platen are brought into contact with each other constantly with uniform pressure. CONSTITUTION:An engaging large diameter part 3a of an end part of the rotary shaft 3 of the platen 4 is engaged in a turning guide groove 9a, and is moved along the groove around the same axis as that for the thermal head 1 with the same radius. Therefore, the relative positions of both of them at the pressure contact part are not changed. The pressure with which the thermal head 1 and the platen 4 are pressed against each other which pressure is generated by forces of both a compression spring 5 and a tension spring 6 remains substantially uniform even when the pressure contact position is changed due to a change of a printing position (the position of the head 1) or deformation of the members, and thermal recording with uniform printed density and favorable quality can be achieved. |
