| 摘要 |
PURPOSE:To shorten the time required for detecting a fault of a frame memory by making the quantity of data which are read out simultaneously from a storage means when detecting a fault of a memory, more than that of the time of a regular printing operation. CONSTITUTION:A frame memory 3 is divided into plural banks, and a fault of the memory 3 is detected by comparing the data between the banks by a comparing part 4. By varying the number of generated clocks of a clock generator, the number of data which are read out in accordance with a read-out signal of once is varied at the time of a regular printing operation and at the time when detecting a fault of the memory, and the number of data which are read out in accordance with a read-out signal of once at the time when detecting a fault of the memory is made as many as possible, by which the time required for detecting a fault of the memory is shortened.
|
