| 摘要 |
PURPOSE:To form a color image in which color printings are accurately superposed by a simple control by providing detecting means at the downstream side of a transfer unit with respect to a conveying direction at the time of forwarding a sheet to detect the end of a sheet at the preceding end. CONSTITUTION:When a sheet P is conveyed to a transfer unit T and detecting means 38 detects the end Pa of the sheet at the preceding end of an image forming direction, a yellow printing is started. When the sheet P is forwarded in the number of pulses to be printed, the sheet P is temporarily stopped, and the sheet is then moved backward. When the means 38 detects the end Pa, the sheet P is temporarily stopped, the forwarding direction of the conveying of the sheet is switched, and magenta printing is simultaneously started. Or, the sheet P is moved backward in predetermined number of pulses, it is then stopped, switched to forwarding. When the means 38 detects the end Pa of the sheet, the magenta printing is started. Similar operation is repeated to superpose three colors. |
