| 摘要 |
Printing apparatus, in particular for performing multi-color printing operations, has a ribbon shift mechanism for selectively interposing different transversely spaced portions of a print ribbon between a print head and platen. The print head is of the impact type and probably, although not necessarily, of the type which moves along the platen to define a print row. When color printing is required, a ribbon having a plurality of longitudinally extending stripes of different colors transversely spaced across its width is used. Selection of required portions or colors of the ribbon is performed by moving the head to pre-selected positions along the print row to engage, for example, a camming mechanism (including a cam and follower) which moves the shift mechanism the required amount to make the selection. Selection of the ribbon portion or color is by program control and in the case of color printing, the range of colors is increased by superimposed printing of the available colors on the print ribbon.
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