| 摘要 |
PURPOSE:To print characters at constant density regardless of the ink color of an ink ribbon by detecting whether the ink ribbon is transparent to identify its type and controlling the electrification of a thermal head in accordance with the type. CONSTITUTION:Ink ribbons are discriminated by the presence of a hold provided previously at positions corresponding to switches 11,12 for ribbon cassettes. If the ribbon is monochromatic, a stepping motor 19 for winding the ribbon is driven, and the ribbon is introduced into an area between the light-emitting part 5 and the light-receiving part 6 of a photocoupler 3. Then it is determined whether the ink ribbon is transparent by detecting the ability of the light- receiving part 6 to receive light from the light emitting part 5. After this, a value for identification of the type of the ink ribbon is stored in RAM 30. Various kinds of data are supplied to CPU 23 in accordance with a detection signal entered from RAM 30. Thus the electrification of a thermal head 20 is controlled through a thermal head drive circuit 27. |
