| 摘要 |
PURPOSE:To enable to detect the position of a movable body, by a method wherin a reciprocally movable body is provided with a light-emitting element, the element is visually checked through a graduated plate, and a light-receiving element is provided on the back side of the graduated plated. CONSTITUTION:On a carriage 3 of a printer, an LED6 emitting visible light is synchronously moved along the graduation 8 on the graduated plate 7, and the position of the carriage 3 can be visually confirmed over the range from a home position 13 to the final printing position by visually checking the light from the LED6 through the graduated plate 7. Photo-transistors 10, 10 are provided at left and right ends of the back side of the plate 7, and the light incident from the LED6 through a slit 12a provided in a slitted plate 12 is detected with high accuracy without being affected by external light. Accordingly, both ends and the current position of the movable body can be detected by a simple construction. |
