IMAGE READING DEVICE

PROBLEM TO BE SOLVED: To improve productivity in reading that uses an ADF while keeping reduced cost.SOLUTION: When a request to read an original document by a controller 13 (image accumulation unit) is not issued in time for the start of reading the original document by an engine 12 (image reading unit), a CPU 14 accumulates image data of the original document read by the engine 12 in a backup memory area secured in a memory 15 in advance. Moreover, when the request to read the original document is issued by the controller 13 before accumulation of the image data of the original document read by the engine 12 in the backup memory area is completed, the memory area specified by the controller 13 is released and an operation of accumulating the image data of the original document read by the engine 12 in the backup memory area is continued.