Patent ID: 7965411

Claim:
An image forming apparatus comprising: a determination unit configured to determine whether or not a target scan line is the first scan line on a raster image; and a transfer unit configured to write raster information in a buffer and transfer the raster information from the buffer to a storage unit, wherein when it is determined by said determination unit that the target scan line is the first scan line, said transfer unit writes raster information based on edge information of the target object in the buffer and transfers the raster information from the buffer to the storage unit, and when it is determined by said determination unit that the target scan line is not the first scan line, said transfer unit further determines whether or not the target scan line is monochromatic, and when it is determined that the target scan line is not monochromatic, said transfer unit writes the raster information of the entire target scan line based on the edge information of the target object in the buffer, when it is determined that the target scan line is monochromatic said transfer unit determines each difference pixel position between the target scan line and the previous scan line stored in the buffer, writes the raster information based on the edge information of the target object in the each determined difference pixel position of the buffer in which the previous scan line is stored, and transfers the raster information from the buffer to the storage unit.