| 摘要 |
A dot matrix printer in which, for the purpose of supervising the quality of the printing of dot matrix characters, an optical sensor (32) is provided for each dot producing element (11) of a print head (5). Each optical sensor (32) includes two glass fibers (34, 36) to carry light from a light-emitting diode to the surface of a record medium and to carry the reflected light to a photodiode. Each printed dot is detected and the sensor output is compared with a delayed or stored print signal which is applied to the drivers for the dot producing printing elements (11). The print head (5) may either be a wire matrix or an ink jet print head. |
