1. Field of the Invention
The present invention relates to an image forming apparatus equipped with a developer replenishment mechanism that replenishes developer to a development device that develops an electrostatic latent image formed on an image bearing member.
2. Description of the Related Art
An image forming apparatus of an electrophotographic system forms a toner image by developing an electrostatic latent image formed on a photosensitive member using developer (referred to as toner, hereafter) in a development device. Since the amount of toner that can be accumulated in the development device is limited, the toner is replenished to the development device from a container that is detachable to the main body of the image forming apparatus.
For example, there is proposed a container that is provided with a rotation portion that is rotated, a pump portion for changing internal pressure of a chamber to discharge toner from the chamber that accommodates the toner, and a converter that converts a rotating motion of the rotation portion into a reciprocating motion of the pump portion (see US 20120014713A1). This container discharges the toner in a chamber by making the pump portion expand and contract according to the rotation of the container. That is, the air that is sucked from a discharging port as the pump portion expands loosens the toner in the chamber, and then, the chamber becomes in a positive pressure state and the air in the chamber forces out the toner, which covers the discharging port, from the discharging port as the pump portion contracts.
Moreover, there is a known conventional configuration in which a detection device in an image forming apparatus detects a detected portion of a container in order to determine whether the container is mounted to the image forming apparatus.
The above-mentioned prior arts suggest a configuration in which the detection device in the image forming apparatus detects the detected portion that rotates with the above-mentioned container in order to check whether the container is mounted to the image forming apparatus and to detect the number of replenishments of toner from the container.
However, when the container rotates just after mounting it to the image forming apparatus so that the detection device is able to detect the detected portion, the toner is discharged from the container whenever the container is mounted to the image forming apparatus.
Accordingly, when the toner is replenished to the development device from the container so as to supplement consumed toner during an image formation after repeating mounting and dismounting of the container, the amount of toner in the development device increases excessively, which causes an image defect.