A thermal transfer colour sheet printer.

摘要

A thermal transfer colour printer is disclosed for printing colour images on individual sheets of paper. One sheet of paper (24) at a time is removed from a stack of paper stored in a cassette (22) and is transported by a reversible platen roller (74) in a first or forward direction at a first predetermined rate. While the sheet of paper (24) is gripped between the reversible platen roller (74) and one or other of pinch rollers (82, 84), slack is removed by a slack removing device (236). A multicoloured ink ribbon (108) with successively arranged colour segments is also transported in the first direction at the same predetermined rate. A thermal printhead (118) presses against the reversible platen roller (74) to press the ink ribbon (108) and sheet of paper (24) together as they move in the first direction. Energisation of the thermal elements (120) on the thermal printhead (118) by colour component signals corresponding to the current colour of the ink ribbon causes the particular current colour to be thermally and selectively transferred to the sheet of paper. The thermal printhead (118) then disengages from the platen roller (74) and the sheet of paper is transported in a set distance in a second direction opposite the first direction, and at a second predetermined rate, and the process of thermally transferring other colours to the sheet of paper is repeated. During the back and forth movement of the sheet of paper, the reversible platen roller (74) and the pinch rollers (82, 84) continuously grip the sheet of paper in order to control precisely the position of the sheet of paper and thereby avoid distortion. A complete colour image is formed on the sheet of paper (24) by superimposing the multiple colours of the ink ribbon (108) as the sheet of paper and the different colours of the ink ribbon repeatedly move past the selectively energised thermal elements (120) of the thermal printhead (118).