Patent ID: 7572001

Claim:
A platen moving mechanism comprising: a casing; a main body frame mounted on the casing, the main body frame having a first recess; a head arranged inside the main body frame for performing processing on a sheet material; a platen roller having a shaft portion that is inserted in the first recess of the main body frame and opposite to the head while the sheet material is fed in a preselected feeding direction between the platen roller and the head during processing of the sheet material by the head; a platen frame for supporting the platen roller and mounted on the main body frame to undergo pivotal movement about a first pivotal shaft between an open state and a closed state to open and close, respectively, an opening communicating with an inner portion of the casing, the platen frame having a second recess that retains the shaft portion of the platen roller during processing of the sheet material by the head and from which the shaft portion can be completely removed in the open state of the platen frame for repair or replacement of the platen roller; a lock arm mounted to undergo pivotal movement about a second pivotal shaft for supporting the platen roller in the closed state of the platen frame, the lock arm having a third recess in which the shaft portion of the platen roller is inserted in the closed state of the platen frame; a head support member for supporting the head and mounted to undergo pivotal movement about the second pivotal shaft in synchronism with pivotal movement of the lock arm and the platen frame; and a switch lever mounted integrally with the lock arm for causing the platen frame to undergo pivotal movement about the first pivotal shaft in synchronism with pivotal movement of the lock arm and the head support member about the second pivotal shaft, the switch lever having an operation portion operable by an operator to undergo movement in any one of at least two directions to cause the platen frame to undergo pivotal movement about the first pivotal shaft; wherein during the processing of the sheet material by the head, the platen frame remains in the closed state such that a main surface of the platen frame forms a part of an exterior wall of the casing and is oriented substantially parallel to the preselected feeding direction of the sheet material, and such that an outer periphery of the platen roller abuts the head while the platen roller is supported so as to be rotatable about the shaft portion thereof and while the shaft portion is securely retained in the second recess of the platen frame and inserted in the first recess of the main body frame and the third recess of the lock arm.