Patent ID: 8957930
Filing Date: 2015-02-17
Classification: B41J

Abstract:
1. A printing apparatus for performing printing processing on a recording medium with a thermal head via an ink ribbon, comprising: a thermal head that heats a plurality of heater elements lined up in a main scanning direction selectively according to printing data; an ink ribbon laid between a supply spool and a wind-up spool; a transport device transporting the ink ribbon to be wound around the wind-up spool or to be rewound around the supply spool; a sensor provided between the supply spool and the thermal head to detect an empty mark attached to an end portion of the ink ribbon to indicate a use limit of the ink ribbon; a peeling member provided between the thermal head and the wind-up spool to peel off the ink ribbon and the recording medium; a rotation amount detecting device detecting a rotation amount of at least one spool of the supply spool and the wind-up spool; and a control device controlling driving of the thermal head and transport of the ink ribbon by the transport device, wherein the control device calculates a diameter of the at least one spool from the rotation amount of the at least one spool detected in the rotation amount detecting device corresponding to a printing length in a sub-scanning direction of the printing data during driving of the thermal head, compares a value of the calculated diameter with a value of a beforehand set diameter, thereby determines whether or not the ink ribbon is near empty indicative of running short, and when determining that the ink ribbon is not the near empty, controls the transport device to wind the ink ribbon around the wind-up spool up to a printing end position in which a rear end of a used portion of the ink ribbon passes through the peeling member, while when determining that the ink ribbon is the near empty, controlling the transport device to wind the ink ribbon around the wind-up spool until the empty mark arrives at a position detectable by the sensor, and then controlling the transport device to rewind the ink ribbon around the supply spool until a front end of an unused portion of the ink ribbon arrives at the printing end position or at a predetermined position beyond the printing end position.