| 摘要 |
PURPOSE:To prevent a developer and a photosensitive body from being damage in case of the burning of a lamp by providing a pre-exposure lamp burning detecting circuit, and detecting a pre-exposure lamp burning out and stopping image forming operation. CONSTITUTION:If the pre-exposure lamp 20 burns out, a voltage Vi is lower than a voltage Vr although the transistor TR 1 of the pre-exposure burning detecting circuit A is on, so the output of a comparator 308 is at H level. Consequently, if the output of the comparator 308 is H level although a controller 301 sends an H level signal to the TR 1, it is judged that the lamp burns out. Then the controller 301 interrupts transfer operation on detecting the burning of the lamp to stop the machine, and also displays the burning of the pre- exposure lamp on a display and operation part 304 to reject succeeding copy start signals, thereby preventing the developer and photosensitive body from being damaged. |
