| 摘要 |
PURPOSE: To move a print head carriage to a precise position by determining a fixed position in response to the output of an optical sensor arranged astride a timing strip and detecting a jam state of the print head carriage base on 'high-to-low' transition period. CONSTITUTION: A printer controller detects a rectangular wave when an optical sensor 74 passes a part 71 between a groove 72 and an end part 73, 75 of a timing strip. A 'low-to-high' transition occurs when the rectangular wave output changes from a 'low' level to a 'high' level, and the printer controller senses the 'low.high' transition. The printer controller positions a print head 22 at a fixed position by the use of information fed by the rectangular wave output. Then the printer controller moves a carriage rightward by a distance from the fixed position, returns to the fixed position (leftward), and checks if it is the fixed position or not. If the print controller senses a correct transition pattern of a correct interval of the rectangular wave from the timing strip 68, the printer controller sets the position as the fixed position. |
