Method and apparatus for controlling transport of thermal transfer ribbon

摘要

An apparatus for use in a thermal printer for printing bar code symbols onto a paper substrate material is provided which utilizes a ribbon having a multi-transfer ink layer. The thermal printer enables the ink ribbon to be transported at a rate that is selectively lower than the transporting rate of the paper substrate. The thermal printer comprises a platen and a thermal head disposed adjacent to the platen having a region defined therebetween through which the paper substrate material is transported at a first rate. Images or symbols are imprinted onto the paper substrate material by operation of the thermal head in cooperation with ink from the multi-transfer ink ribbon advanced to the region. A supply hub carries a supply of the ribbon, and a first motor is mechanically linked to the supply hub. The first motor rotates the hub in a direction opposite to a direction of advancement of the ribbon. A roller is mechanically linked to the first motor and has a surface engaging the ribbon provided with a friction coefficient sufficient to prevent slippage of the ribbon across the surface. A second motor applies a tension on the ribbon, and a clutch interposed between the first motor and the supply hub permits controlled slippage of the supply hub to permit advancement of the ribbon. A take-up hub mechanically linked to the second motor receives the ribbon after its passage through the region between the platen and the thermal head.