Patent ID: 8248668

Claim:
An image forming apparatus comprising an image processing device, the image processing device comprising: a first image reading unit configured to read image data on a front side of a document page; a second image reading unit configured to read image data on a back side of the document page; a first image processing unit configured to process the image data read by the first image reading unit; a second image processing unit configured to process the image data read by the second image reading unit; a memory configured to store the image data processed by the first image processing unit and the second image processing unit; a memory control unit to control access to the memory; and a bus switch configured to connect the first image processing unit and the second image processing unit to the memory, the bus switch comprising a first compression unit configured to compress the image data processed by the first image processing unit and a second compression unit configured to compress the image data processed by the second image processing unit, the bus switch configured to output to the memory encoded data generated by compressing the image data using the first compression unit and the second compression unit, wherein the first compression unit and the second compression unit are configured to change a compression method used therein depending on whether or not the read image data is reused, wherein, in a case in which the read image data is reused, the image data is enlarged in a sub-scanning direction when read and then reduced for transfer to the bus switch.