Image forming apparatus and image forming method

An image forming method, comprising:

• storing image data of a predetermined test pattern image in a storage device;
• with a printer, forming a first image on a sheet according to the image data of the predetermined test pattern image;
• with an image reading unit, reading the first image formed on the sheet;
• generating a gamma correction table specifying a maximum output density for forming a second image on a sheet, the maximum output density being set according to a maximum read density that has been read from the first image by the image reading unit;
• and
• applying a gamma correction to a pixel of image data of the second image in accordance with the gamma correction table according to whether or not the pixel of the image data of the second image represents an edge portion in the second image.

An image forming apparatus comprising:

• a printer configured to form an image on a sheet according to image data supplied to the printer;
• a first storage device that stores image data of a predetermined test pattern image;
• an image reading unit configured to read the image formed on the sheet;
• a second storage device that stores a gamma correction table specifying a maximum output density of the printer, the maximum output density being determined according to a maximum read density that has been read from a sheet on which the predetermined test pattern image has been formed by the printer;
• and
• a controller configured to
• detect whether or not a pixel of the image represents an edge portion of the image;
• and
• apply a gamma correction to a pixel of the image data or not in accordance with the gamma correction table according to whether or not the pixel represents an edge portion of the image.