Patent ID: 8005379

Claim:
An image forming apparatus, comprising: a conveying rotation unit for conveying a toner image formed on an outer surface of the conveying rotation unit by rotating movement of the conveying rotation unit; a toner amount changing section for changing a toner adhering amount of the toner image formed on the conveying rotation unit; a toner length changing section for changing a length of the toner image formed on the conveying rotation unit in a circumferential direction of the conveying rotation unit; a toner amount detecting section for detecting the toner adhering amount of the toner image formed on the conveying rotation unit; and a control section for controlling the toner amount changing section and the toner length changing section and for storing a detection result of the toner amount detecting section, wherein the toner amount detecting section detects a toner adhering amount of a detection pattern of a toner image formed on the conveying rotation unit, based on a detection result of the toner amount detecting section regarding the toner adhering amount, the control section controls the toner amount changing section to form a toner image having a given toner adhering amount on the conveying rotation unit, when a detection pattern is formed on the conveying rotation unit, the control section determines a circumference-directional length of the detection pattern formed this time, based on the detection result of the toner amount detecting section regarding the detection pattern formed immediately before.