A replaceable unit includes a communication unit to perform communication with a main body, and a non-volatile memory storing code information indicating whether a configuration of an error detection code is a first configuration or a second configuration. The communication unit stores, in a volatile memory, the code information, executes the communication in accordance with the code information in the volatile memory, and, upon receiving a change command, updates the code information stored in the volatile memory. The first configuration uses an error detection code of a first code length, the second configuration uses an error detection code of a second code length longer than the first code length, and the first configuration is used for the change command in order to change from the first configuration to the second configuration.

A drum unit detachably attachable to an image forming apparatus includes: a frame; a photosensitive drum; a toner cartridge including a toner casing and a toner memory; a connector electrically connected to the image forming apparatus; and a relay board electrically relaying the toner memory and the connector. The toner memory performs communication according to a standard that sets a value of data on a basis of a voltage for data communication at a timing when a prescribed period of time has elapsed since the voltage has made a prescribed change. The toner memory consists of three terminals as electrical contacts. The three terminals are a power supply terminal for supplying a supply voltage to the toner memory, a ground terminal, and a data terminal for communication of data to be written into the toner memory and data to be read from the toner memory.

A method for determining authenticity of a security device of a component in an imaging device includes receiving, by the security device, an authentication challenge including one or more commands and executing, by the security device, the one or more commands in response to receiving the authentication challenge. A magnetic field profile is generated based on current drawn by the security device from a power source while the security device is executing the one or more commands, the generated magnetic field profile indicating an authentication response of the security device to the authentication challenge for use in determining authenticity of the security device.

An image forming apparatus to which a cartridge including a cartridge substrate is attachable includes a main body electrical substrate, a main body ground terminal connected to the main body electrical substrate and configured to take a ground voltage, a first main body terminal connected to the main body electrical substrate and configured to transmit one of a power supply voltage, a data signal that indicates information, and a synchronization signal, a second main body terminal connected to the main body electrical substrate and configured to transmit remaining two of the power supply voltage, the data signal, and the synchronization signal.

The cartridge substrate includes a cartridge ground terminal connected to the main body ground terminal, a first cartridge terminal connected to the first main body terminal, and a second cartridge terminal connected to the second main body terminal.

A method of converting a CMYW toner printer to a CMYK printer that prints with black toner, comprising the steps: providing a CMYW toner printer; wherein the CMYW toner printer has four starting toner printing cartridges; wherein the four starting toner printing cartridges comprise a white toner printing cartridge, a cyan toner printing cartridge, a magenta toner printing cartridge, and a yellow toner printing cartridge; removing one or more of the four starting toner printing cartridges from the CMYW toner printer, such that there are one or more empty toner cartridge slots; providing a black toner printing cartridge that are each filled with black toner; and installing the black toner printing cartridge into the one or more empty toner cartridge slots.

According to examples, a toner refill apparatus may include a chamber to house a toner, in which the chamber may include an insertion section, the insertion section to be inserted into a refill port of a toner cartridge and including a discharge opening, the refill port including an electrical circuit component. The apparatus may also include a valve mechanism positioned at the discharge opening to control output of the toner from the chamber through the discharge opening, in which an actuator may engage the valve mechanism and may controllably open the valve mechanism. The apparatus may further include an electronic chip to be in electrical communication the electrical circuit component, in which a controller may activate the actuator based on a detection that the electronic chip is in contact with the electrical circuit component.

A method of determining authenticity of a component in an imaging device includes generating an analog signal as an authentication challenge to the component. The method further includes generating, by the component, a response to the authentication challenge by converting the analog signal into one or more digital values and capturing a derivative of the one or more digital values as the response. Authenticity of the component is determined by comparing the response with an expected response.

An image-forming apparatus includes: a toner cartridge configured to accommodate toner; a drum cartridge for use with the toner cartridge; and a controller. The drum cartridge includes a photosensitive drum, and a drum memory storing a first type information indicating a type of the drum cartridge. The controller is configured to communicate with the drum memory. The controller is configured to perform: reading the first type information from the drum memory; and changing an operation of the image-forming apparatus based on the type indicated by the first type information.

A drum cartridge including a photosensitive drum, a drum frame configured to retain the photosensitive drum and to accept a developing cartridge including a toner memory, which stores information concerning the developing cartridge, a first connector electrically connectable with the toner memory in the developing cartridge under a condition where the developing cartridge is attached to the drum frame, a relay board electrically connectable with the first connector, a second connector electrically connectable with a connector in an image forming apparatus and with the toner memory through the relay board, and a thermistor electrically connectable with the relay board, is provided.

There is provided an image forming system including at least a first image forming apparatus that includes a first image forming unit and an obtaining unit configured to obtain operation-related information related to an operation of the first image forming unit. The image forming system further includes a carryover unit configured to carry over, to a second image forming apparatus, information related to an operation of a second image forming unit of the second image forming apparatus among the operation-related information obtained by the first image forming apparatus when the second image forming apparatus is newly used in the image forming system. The operation-related information includes operation history information of the first image forming unit.