Patent ID: 8515301

Claim:
An image forming device comprising: an image carrier; an exposing part configured to form an electrostatic latent image on the image carrier in dot unit; a developing member configured to develop the electrostatic latent image by using developer; a developer reserving part configured to supply the developer to the developing member; a detection part configured to detect a developer remaining amount in the developer reserving part; a first count part configured to count a rotation number of the image carrier during print performance; a second count part configured to count an exposing dot number exposed by the exposing part; a first calculation part configured to calculate a print duty for a print sheet based on the rotation number of the image carrier and the exposing dot number; and a discarding part that is configured to change an amount of the developer discarded depending on the developer remaining amount detected by the detection part, and to discard a larger amount of the developer when the developer remaining amount is equal to or less than a standard remaining amount, and when the print duty is less than a standard duty, compared to the amount of the developer discarded when the developer remaining amount is more than the standard remaining amount.