Patent ID: 8867049

Claim:
An image forming apparatus comprising: a first read device configured to read an image on a first surface of an original document, line by line, in a main scanning direction, and to produce a first band data formed of at least one line; a second read device configured to read another image on a second surface of the original document, line by line, in the main scanning direction and to produce a second band data formed of at least one line during the reading of the first surface by the first read device; an image data processor configured to produce printing band data by linearly combining the first band data with the second band data, during the reading of at least one of the first surface and the second surface performed by the first read device and the second read device, respectively; and a printing device configured to start printing a combined image of the image on the first surface and the image on the second surface based on the printing band data produced by the image data processor on a printing sheet before the first read device completes reading the image on the first surface of the original document.