A printer.

摘要

A printer (1) comprises a thermal print head (17), a platen roller (11), a thermal ribbon supply spool (14) and a thermal ribbon take-up spool (15). Paper to be printed is fed between the platen roller (11) and the print head (17) by means of a friction feed mechanism and the print head (17) is raised to trap the paper and a thermal ribbon (13) between the platen roller (11) and the print head (17). The thermal ribbon (13) is pulled along with the paper and the printing operation is carried out, with the thermal print head (17) printing through the thermal ribbon (13) onto the paper. The printer (1) is provided with sensing and actuating means (16) for detecting a reduction in ribbon tension between the printing zone and the ribbon take-up spool (15) and rotating the ribbon take-up spool (15) in the ribbon take-up direction thereof. Sensing and actuating means (not shown) may also be provided for detecting an increase in ribbon tension between the printing zone and the ribbon supply spool (14) and rotating the ribbon supply spool (14) in the ribbon supply direction thereof.