Image forming apparatus and toner amount calculating method

An image forming apparatus, comprising:

• an exposure device;
• a base toner amount determining unit configured to determine a base toner amount without taking edge effect into account, the base toner amount corresponding to a pixel value of image data for which gradation correction has not been performed;
• a laser profile applying unit configured to perform for the base toner amount a first spatial filter process corresponding to a laser profile of the exposure device;
• an edge emphasis amount determining unit configured to perform a second spatial filter process for the base toner amount before the first spatial filter process or after the first spatial filter process and thereby determine an edge emphasis amount corresponding to the edge effect;
• a gain control unit configured to control a gain of the edge emphasis amount;
• and
• a toner counter configured to count as a toner consumption amount a sum of the base toner amount after the first spatial filter process and the edge emphasis amount;
• wherein the gain control unit multiplies the edge emphasis amount by a coefficient corresponding to the base toner amount after the first spatial filter process and thereby controls a gain of the edge emphasis amount.