Image forming apparatus having a detachable cartridge and developer residual amount sensor

An image forming apparatus comprising:

• an image forming apparatus body having a cartridge mount space in which a cartridge having a developer container filled with developer is detachably loaded and mounted;
• a developer residual amount sensor including a cartridge confronting face that confronts the outer wall of the developer container when the cartridge is mounted in the cartridge mount space, a supported face formed at the opposite side of the cartridge confronting face, a sensor head which is projected from the cartridge confronting face and whose tip end face serves as a developer residual amount detection face to be pressed against the outer wall of the developer container, an inclination regulating projection member which is projected from the cartridge confronting face at a position distant from the sensor head and can come into contact with the outer wall of the developer container, the developer residual amount sensor detecting the amount of the developer in the developer container under the state that the developer residual amount detection face is brought into contact with the outer wall of the developer container;
• a sensor supporting face that supports the supported face of the developer residual amount sensor;
• and
• a fulcrum member which is projected from one of the sensor supporting face and the supported face of the developer residual amount sensor toward the other face, the fulcrum member including a tip portion and the other face being rotatable with respect to the tip portion of the fulcrum member as a fulcrum under the state that the tip portion of the fulcrum member is brought into contact with the other face.

A sensor holding comprising:

• a sensor for detecting a residual amount of developer and an inclination regulating projection member, which are brought into contact with the outer wall of a developer container when a cartridge is mounted in a cartridge mount space of an image forming apparatus body;
• a holding member that fixedly holds the sensor and the inclination regulating projection member;
• and
• a supporting member that rotatably supports the holding member so that the sensor and the inclination regulating projection member are positionally variable in the height direction thereof.