An image forming apparatus comprises a fixing device comprising a heater for heating a sheet on which an image is formed and a non-volatile memory in which characteristic information of the heater is stored. The fixing device is replaceable. In a case where the fixing device is replaced, the image forming apparatus starts to supply power to the heater before completing to read the characteristic information from the fixing device replaced. Due to this, the image forming apparatus can promptly heat the heater of the fixing device than before.

A developing cartridge is provided. The developing cartridge includes a housing which accommodates developer therein, a receiving member provided which couples with a force output member of an image forming apparatus to receive a driving force, a developing roller which rotates by the driving force received by the receiving member; a detectable rotary member having a first detectable portion and a second detectable portion and rotates by the driving force from a first rotational position where the first detectable portion is detected by a detection member provided in the image forming apparatus to a second rotational position where the second detectable portion is detected by the detection member, and a cut-off mechanism which cuts off a transmission of the driving force from the receiving member to the detectable rotary member in a state where the detectable rotary member is positioned in the second rational position.

Disclosed is a developing cartridge configured to be removably mounted in a main assembly of an imaging apparatus. In some embodiments disclosed, the developing cartridge includes: a cartridge body; a drive force receiving unit including a coupling member, disposed at a first end of the developing cartridge, configured to receive a drive force from the imaging apparatus; a driving member, disposed at the first end of the developing cartridge, configured to receive the drive force and move; a transmission member, receiving a force from the driving member to cause at least a portion of the transmission member to move along a longitudinal direction of the cartridge body; and a detected member provided at a second end of the developing cartridge, configured to be driven by the transmission member.

An image forming apparatus includes an image forming unit, a mounting portion, and a detecting device. The image forming unit forms an image using toner. A toner container of a given type is removably mounted on the mounting portion. The detecting device detects whether or not the toner container has been mounted on the mounting portion. The toner container and the mounting portion respectively include an engaging protrusion and an engaging hole. The engaging protrusion and the engaging hole are engageable with one another. The engaging protrusion and the engaging hole engaged with one another causes the detecting device to detect that the toner container has been mounted on the mounting portion. The engaging protrusion and the engaging hole are of form configured according to the toner container type.

A developing cartridge may include a rotary gear rotatable about one axis and a detection gear rotatable about another axis. The detection gear is configured to be not rotatable with the rotary gear in a case where the rotary gear rotates from a first rotational position to a second rotational position, while being configured to be rotatable with the rotary gear in a case where the rotary gear rotates from the second rotational position to a third rotational position.

A developing cartridge is provided. The developing cartridge includes a housing which accommodates developer therein, a receiving member which receives a driving force output member provided in an image forming apparatus, a developing roller which rotates by the driving force received by the receiving member, and a detectable rotary member including a detectable portion, which is a detection target to be detected by a detection member provided in the image forming apparatus, and a contact portion which is provided away from the detectable portion. The detectable rotary member rotates from a retreat position to an initial position where the detectable rotary member is rotated by the driving force received by the receiving member, by the contact portion contacting an interference member fixed in the image forming apparatus in a process of mounting the developing cartridge into the image forming apparatus.

A developing cartridge may include multiple rotary members, at least one of the rotary members configured to be detected by an image forming apparatus. In one example, the rotary members may include engagement portions configured to engage with one another to rotate the rotary members. Additionally or alternatively, in a case where one rotary member is in a driven position, the other rotary member may be rotatable a predefined amount from a non-driving state in which the other rotary member is rotatably disengaged from the one rotary member, to a driving state in which the other rotary member rotatably engages the one rotary member with the engagement portions in contact with one another.

An image forming apparatus includes an image forming unit, a mounting portion, and a detecting device. The image forming unit forms an image using toner. A toner container of a given type is removably mounted on the mounting portion. The detecting device detects whether or not the toner container has been mounted on the mounting portion. The toner container and the mounting portion respectively include an engaging protrusion and an engaging hole. The engaging protrusion and the engaging hole are engageable with one another. The engaging protrusion and the engaging hole engaged with one another causes the detecting device to detect that the toner container has been mounted on the mounting portion. The engaging protrusion and the engaging hole are of form configured according to the toner container type.

An image forming apparatus includes an apparatus main body and a cartridge configured to be mounted to and detached from the apparatus main body. The cartridge includes a rotating member which is configured to rotate and comprises a detected portion and a first engaging portion. The apparatus main body includes a detecting portion configured to detect the detected portion and a second engaging portion configured to engage with the first engaging portion. At least when the detecting portion detects the detected portion, the first engaging portion and the second engaging portion are engaged with each other by rotation of the rotating member.

An image forming apparatus comprises a fixing device comprising a heater for heating a sheet on which an image is formed and a non-volatile memory in which characteristic information of the heater is stored. The fixing device is replaceable. In a case where the fixing device is replaced, the image forming apparatus starts to supply power to the heater before completing to read the characteristic information from the fixing device replaced. Due to this, the image forming apparatus can promptly heat the heater of the fixing device than before.