| 摘要 |
PURPOSE:To prevent an interrupted paper from discoloring by providing a photoelectric sensor which detects paper feeding holes, detecting abnormality in paper feeding by the comparing the output of the sensor with previously determined reference and stopping the exposure of a xenon lamp. CONSTITUTION:The photoelectric sensor constituted of a photoelectric switch 15 provided with a light emitting part and a light receiving part, and a light reflecting plate 16 is provided on the position of the paper feeding holes of the paper on the paper advancing side. A beam emitted from the light emitting part of a switch 15 is reflected by the reflecting plate 16. The resultant intense reflected beam is detected by the light receiving part to detect the paper feed holes, and its output is sent to control part 17. The control part 17 compares the period when the switch 15 is outputting the signal with the one under a normal condition. When the control part 17 recognizes any differences exceeding of a previously determined range, the control part 17 instantaneously stops both the light emission of the xenon lamp and printing operation. Thus, the interrupted paper can be surely prevented from discoloring caused by excess light emission. |
