This invention provides an image forming apparatus which communicates with a plurality of cartridges without increasing its circuit dimension. To accomplish this, the apparatus includes a control circuit having an output terminal for outputting a clock signal and data signal used to generate a transmission signal to the cartridge, and an input terminal for receiving a transmission signal from the cartridge. The apparatus includes N connectors each having the first electrode which is connected to the first electrode surface of each cartridge, and the second electrode which is connected to the second electrode surface. The apparatus includes a 1-to-N first signal line for connecting the input terminal to the N first electrodes, and a 1-to-N second signal line for connecting the output terminal to the N second electrodes. The apparatus includes N switching units which are interposed between 1-to-N branch points and the second electrodes on the second signal line.

A developer cartridge according to one aspect described herein is attachable to a photoconductor unit that comprises a photoconductive drum. The developer cartridge may comprise a main body having an opening, the main body comprising an electric circuit, a front cover configured to move to an opening position in which the opening of the main body is exposed and to a closing position in which the opening of the main body is closed, a first terminal electrically connected to the electric circuit, a photosensitive drum, and a developer cartridge comprising a developing roller, developing frame having a pressed portion, memory unit and second terminal. The front cover may include a pressing portion configured to press the pressed portion of the developing frame in a direction from the developing roller toward the photosensitive drum, and wherein the second terminal faces to the front cover when the front cover is in the closed position.

An information storage device installed in a removable device configured to be removably installed in an image forming apparatus body, includes: an information storage unit that stores information communicated between the image forming apparatus body and the removable device; a terminal that comes in contact with a body side terminal; and a substrate that holds the information storage unit and the terminal and includes a hole configured to be engaged with a protruding section installed in the image forming apparatus body. The terminal includes a plurality of terminals each including one of a plurality of metallic plates arranged in a transverse direction thereof. An earth terminal, which comes in contact with a body side earth terminal formed in the protruding section, is formed in the hole. The hole is disposed at a position sandwiched between two metallic plates among the plurality of metallic plates.

Presented is an image forming apparatus that includes a plurality of photoconductors, a sensor, a first memory, and a processor. The photoconductors include first and second photoconductors on which a toner image is formed in response to an image being formed. The sensor detects a physical amount that changes in response to a deterioration state of the first photoconductor. The first memory collects and stores a history of the physical amount and usage status information relating to a usage status of the first photoconductor. The processor performs a prediction of a lifespan of the second photoconductor and determination of a failure of the second photoconductor based on the history of the physical amount and the usage status information of the first photoconductor, and usage status information relating to a usage status of the second photoconductor.

A cartridge includes a photosensitive drum rotatable about an axis extending in an axial direction; a memory including a storing element configured to store information, a memory contact electrically connected to the storing element, and a substrate having a surface on which the memory contact is provided; and a frame which supports the photosensitive drum, on which the substrate is mounted, and which includes a first end with respect to the axial direction and a second end opposite from the first end. The frame includes a container provided with an accommodating chamber for accommodating a developer collected from the photosensitive drum and with an opening communicating with the accommodating chamber and includes a mounting member mounted on the container so as to cover the opening. The mounting member includes a supporting portion for supporting the substrate.

Many devices, such as printers, work with one or more removable unit. Often, the removable units have an electronic circuit that used to communicate with the device. It may be desirable to provide a replacement unit in these devices. The replacement unit must include an electronic circuit that is able to communicate with the original device. Disclosed is a method and apparatus where a replacement unit is provided with a new electronic circuit and a used electronic circuit. The new electronic circuit is electrically connected to the used electronic circuit and uses the used electronic circuit to facilitate communication with the host device.

A cartridge insertable into a main assembly of an image forming apparatus includes a first unit including a first bearing portion for supporting an image bearing member, a second unit including a second bearing portion for supporting a developer carrying member, and a storing medium including an electrical contact. The second bearing portion is provided inside the first bearing portion with respect to a rotational axis direction of the image bearing member. At least a part of the storing medium is supported by the second unit and is provided at a position outside the second bearing portion and inside an outermost configuration of the first unit with respect to the rotational axis direction. The electrical contact is faced toward a downstream with respect to an inserting direction of the cartridge into the main assembly.

A method of operating a cartridge chip installed in an imaging device including transmitting a first value to the imaging device in response to a first request from the imaging device; if the first value is accepted by the imaging device, (a) receiving an authentication command from the imaging device and (b) operating in a first mode of operation; if the value is not accepted by the imaging device, waiting for the imaging device to transmit a second request; transmitting a second value to the imaging device in response to a second request from the imaging device, the second value not equaling the first value; if the second value is accepted by the imaging device, (a) receiving an authentication command from the imaging device and (b) operating in a second mode of operation.

A physical unclonable function (PUF) located on a supply item for an imaging device is disclosed. The PUF has a toothed rack configured to mate with a gear. During reading operations, the gear turns and translates the PUF linearly under a magnetic sensor. This configuration is inexpensive and robust. Other devices are disclosed.

An elongate physical unclonable function (PUF) is disclosed. The PUF has a longitudinal axis and contains a plurality of small magnetic particles. A much larger magnet is positioned on the longitudinal axis to indicate a home position. A low-cost linear translation mechanism may be used to read the PUF by referencing position information to the home position. Other devices are disclosed.