| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of an erroneous copy and lessen a burden associated with a copying operation by disabling a double sided copying mode, when an image exists at least on one side of a transfer paper sheet. SOLUTION: A double side copying part 6 is made of a double sided copying mechanism 4 and a printer engine (image forming part) 5. Also, a controller part 3 is formed out of a microprocessor, a memory or the like. When a transfer paper sheet is set in the paper sheet feed tray of a feeding part 7, the surface of the transfer paper sheet is read with a CCD sensor. When a value read with the sensor shows that the total area of black zones is equal to or more than a certain value, the controller part 3 judges the paper sheet as copied on one side. Then, the controller part 3 causes an operation part 8 to indicate an alarm and disables the double side copying selector key of the operation part 8, thereby prohibiting a double sided copying process. |
