Patent ID: 8488203

Claim:
An image forming apparatus comprising: a skew correcting unit that performs skew correction by dividing an input image that has undergone a halftone process into image data in a predetermined skew correction area in a main scanning direction and by shifting the image data in the skew correction area in a sub-scanning direction; an edge detecting unit that detects whether a pixel at a division position between the image data after shifting is an edge pixel that constitutes an edge in accordance with concentrations of a set of pixels including the pixel at the division position within a predetermined area and a shift direction of the skew correction; a correction area determining unit that, if it is detected that the pixel at the division position is the edge pixel, determines a correction area that is an area of pixels including the edge pixel to be subjected to concentration correction within the skew correction area; and an edge correcting unit that corrects concentrations of the pixels within the correction area.