| 摘要 |
PURPOSE: To surely detect the abnormal lighting of a lamp without increasing in the cost and further, erroneous detection by using a photosensor for monitoring a reflected light quantity, for detecting the abnormal lighting of the lamp and detecting the abnormal lighting only when a cover is closed. CONSTITUTION: When the lamp 22 is lighted, light radiated from the lamp 22 reflected by an original 1, the cover 16 or a reference reflection plate 39, the reflected light is detected by the photosensor 36 and a signal for showing the reflected light quantity is fetched in a control circuit. At this time, it is decided whether the output of the photosensor 36 exceeds a prescribed threshold or not. When the output exceeds the prescribed value, the lighting time is monitored and when the lighting time exceeds the prescribed value, the opening/ closing of the cover (platen cover) 16 are monitored. When the output of the photosensor exceeding the prescribed value is continued regardless of the closing of the platen cover 16, the lamp is abnormally lighted and an error code for showing the abnormal lighting of the lamp is displayed on a display part. |
