| 摘要 |
PURPOSE:To prevent a 1st image surface from being retained in a machine owing to the shortage of a recording agent at the time of double-sided recording and to facilitate an operation by providing a recording means and a means which detects whether or not there is the recording agent left, detecting whether or not there is the recording agent at the time of 1st image surface recording, and judging that there is no recording agent without performing the detection at the time of 2nd image surface recording. CONSTITUTION:A high-voltage electrifier 7, a transfer electrifier 9, a cleaning device 10, and a developing device 8 which has a toner detector 80 for detecting whether or not there is toner and contains the toner are provided for the photosensitive drum 6 of a laser beam printer. Images are formed on both surfaces of a printing form sent from the paper feed cassette 11 of this printer according to commands from a sequence controller 2 (22). When the controller 22 sends a signal which instructs printing operation from an external controller 21 to designate 2nd surface recording, the toner 80 detects and indicates whether there is toner or not, when the 2nd surface recording is specified, the presence/ absence detection of the recording agent is not performed and when it is judged that there is no recording agent, recording operation for a next page is disabled. |
