An image forming apparatus includes first, second, and third acquisition processing portions. The first acquisition processing portion acquires the potential value of a charged area, charged by the charging member, on the image-carrying member. The second acquisition processing portion acquires a state value regarding the state of a surface layer of the image-carrying member based on the potential value of the charged area acquired by the first acquisition processing portion and the current value of a charging current flowing through the charging member during formation of the charged area. The third acquisition processing portion acquires the electrical resistance value of the transfer member based on the state value acquired by the second acquisition processing portion, the voltage value of a transfer voltage applied to the transfer member, and the current value of a transfer current flowing through the charged area in response to application of the transfer voltage.

A server apparatus including a first communication device and a first computing device. The first communication device communicates with an image forming apparatus via a network. The first computing device includes a processor, and acts as a data acquirer, a dimension reduction processor, and a residual service life calculator, when the processor executes a first control program. The data acquirer acquires observation data of a first number of dimensions from the image forming apparatus, via the first communication device. The dimension reduction processor converts the observation data of the first number of dimensions into characteristic data of a second number of dimensions fewer than the first number of dimensions. The residual service life calculator calculates a residual service life of a replaceable unit in the image forming apparatus, on a basis of the characteristic data.

An image forming apparatus includes: a photosensitive drum; a developing roller; a separation mechanism configured to switch a state of the photosensitive drum and the developing roller between a contact state and a separation state; a main memory storing therein a first rotation number and a second rotation number; and a controller configured to perform calculating a deterioration quantity of the photosensitive drum based on the first rotation number and the second rotation number in the main memory. A surface of the developing roller contacts a surface of the photosensitive drum in the contact state, whereas the surface of the developing roller is separated from the surface of the photosensitive drum in the separation state. The first rotation number is the number of rotations of the photosensitive drum in the contact state, and the second rotation number is the number of rotations of the photosensitive drum in the separation state.

An image forming apparatus, including: a housing; a photoconductor; a developing unit configured to form a developer image on the photoconductor; a developer cartridge storing developer, the cartridge being removably mountable on the housing, a supplier configured to supply the developer from the developer cartridge to the developing unit; and a controller configured to execute a first printing process of forming a developer image by use of the developer supplied from the developer cartridge, when the developer cartridge is being mounted on the housing, and a second printing process of forming a developer image by use of the developer remaining in the developing unit, when a usage amount of the developing unit is not less than a predetermined value and the developer cartridge is not being mounted on the housing, wherein the controller does not execute the second printing process when the usage amount is less than the predetermined value.

An image forming apparatus comprises a main unit, a main unit memory, a drum cartridge, a toner cartridge, and a controller. The main unit memory stores printer identification information. The drum cartridge comprises a drum memory that stores drum identification information. The toner cartridge comprises a toner memory that stores toner identification information. The controller is configured to store in the main unit memory the drum identification information stored in the drum memory and store in the drum memory the printer identification information stored in the main unit memory, if it determines that the drum cartridge installed in the main unit is new, and store in the main unit memory the toner identification information stored in the toner memory and store in the toner memory the drum identification information stored in the drum memory, if it determines that the toner cartridge installed in the main unit is new.

An image formation apparatus according to one or more embodiments includes: an engagement part to which a replacement unit with a first communication part is detachably attachable; a second communication part configured, in a state where the replacement unit is attached to the engagement part, to communicate wirelessly with the first communication part of the replacement unit; and a control unit programmed to control the second communication part. In a process of causing the second communication part to communicate wirelessly with the first communication part a plurality of times, the control unit detects a change in a response from the first communication part.

A memory control device includes a memory control part that controls memory through an interface part in accordance with a predetermined communication regulation, an illegal access detection part that detects an illegal access to the memory according to an access state from the memory control part to the memory and a signal state of the interface part, and a signal control part that switches the signal state of the interface part from a write-allowed state, in which the interface part is able to be written, to a write-inhibited state, in which the interface part is protected from being rewritten, when the illegal access is detected by the illegal access detection part.

An image forming apparatus includes a replenishment empty history recording portion, a post-empty attachment detecting portion, and an image creation restricting portion. The replenishment empty history recording portion records replenishment empty history information to a storage device in correspondence with one of the plurality of developer containers in which a replenishment empty state was detected in a first attachment portion. The post-empty attachment detecting portion detects whether or not a second attachment portion is in a post-empty container attached state where the developer container corresponding to the replenishment empty history information recorded in the storage device is attached to the second attachment portion. The image creation restricting portion, upon detection of the replenishment empty state, restricts an operation of an image creating device, and upon detection that the second attachment portion is in the post-empty container attached state, releases a restriction on the operation of the image creating device.

An image forming apparatus includes an image bearing member, a toner image forming portion, a transfer member, a cleaning member, and a controller configured to carry out a process for notifying information on a lifetime of the image bearing member on the basis of information on contact pressure of the cleaning member to the image bearing member.

A management system includes: a management server; one or more image forming apparatuses that notify the management server of information on a remaining amount of toner; and one or more terminals, in which the management server makes a toner remaining amount history by combining the information on the remaining amount of toner with time and date information, detects, based on the toner remaining amount history, that toner replacement has been performed when an increase rate of the remaining amount of toner exceeds a threshold value, and determines, based on the contract value, whether the remaining amount of toner before the toner replacement is not more than the contract value when the toner replacement is detected, and notifies the one or more terminals of that the performed toner replacement corresponds to a contract violation when the remaining amount of toner before the toner replacement is more than the contract value.