Image forming apparatus

An image forming apparatus comprising:

• an image carrier on a surface of which an electrostatic latent image is formed;
• a developing unit which feeds toner to the electrostatic latent image to form a toner image on the surface of the image carrier;
• a toner container which has a transport screw and which drives the transport screw to rotate to transport toner contained in the toner container to supply the toner to the developing unit;
• a pixel counter which counts a number of pixels in toner images that have been formed on the surface of the image carrier since a start of use of the toner container;
• and
• a used toner amount estimator which estimates an amount of toner used,
• until a cumulative value of a number of revolutions of the transport screw reaches a predetermined number, based on the cumulative value of the number of revolutions of the transport screw and,
• after the cumulative value of the number of revolutions of the transport screw has reached the predetermined number, by multiplying a pixel count value of the pixel counter by a coefficient,
• wherein the used toner amount estimator corrects the coefficient based on the pixel count value of the pixel counter as observed when the cumulative value of the number of revolutions of the transport screw reaches the predetermined number.