An image forming apparatus includes a photoconductor, a charger, a detection unit, and a determination unit. The charger charges the photoconductor. The detection unit detects an actual charging potential of the photoconductor after the photoconductor is charged by the charger. The determination unit determines one of a plurality of causes related to a charging abnormality of the photoconductor based on a relationship between a standard charging potential of the photoconductor to be obtained by charging by the charger and a charging potential detected by the detection unit.

A sheet characteristic detection device includes: a detector that is disposed on a sheet ejection path through which a sheet is ejected and that detects an electrical resistance value of the sheet; and a charge neutralizer that is disposed on a downstream side of the detector on the sheet ejection path and that neutralizes electric charge on the sheet.

A power supply device that applies a voltage in which a direct-current (DC) voltage and an alternating-current (AC) voltage are superimposed on each other to a charging member that charges an image bearer, includes: an AC voltage generation circuit that generates the AC voltage; a DC voltage generation circuit that generates the DC voltage; a DC current detection circuit provided on an output terminal side of the DC voltage generation circuit, which detects an output DC current flowing into the image bearer; and a reduction circuit that reduces an inflow of an AC current to the DC current detection circuit.

An image forming apparatus includes a fixing member that fixes, onto a recording material, a toner image that has been transferred onto the recording material, a recovery roller that recovers toner adhering onto the fixing member, a cleaning unit, and a controller. The cleaning unit includes a cleaning web that cleans the recovery roller, a first roller around which the cleaning web is wound in advance, a second roller that winds the cleaning web supplied from the first roller, and a third roller that presses the cleaning web against the recovery roller to clean the recovery roller. The controller stops a rotation of a rotor of a motor that drives the second roller, in a case where a value corresponding to a torque applied to the rotor exceeds a threshold while the rotor is rotating.

An image forming apparatus includes a developing member, a first detection processing portion, and an acquisition processing portion. The developing member conveys developer to a facing portion between the developing member and the image-carrying member. The first detection processing portion detects a first development current for each of a plurality of specific voltages with different DC voltage values applied to the developing member, the first development current flowing, in response to application of the specific voltages, through the facing portion including the developer and a specific exposed area, formed by the light emitting portion, on the image-carrying member. The acquisition processing portion acquires a potential value of the specific exposed area based on the DC voltage values of the specific voltages and current values of the first development current, detected by the first detection processing portion, corresponding to the respective specific voltages.

An image forming apparatus includes a photoreceptor, a charger, an exposure device, a developing device, a transfer device, a power supply, a detection element, and a processor. The processor sets a transfer bias used in image forming processing based on the resistance value calculated using the value of the transfer bias supplied by the power supply, a measured value measured by the detection element, and the potential of the photoreceptor estimated from the charging potential at which the charger charges the photoreceptor if the measured value is measured, and determines the state of the photoreceptor based on a change in the surface potential of the photoreceptor if the charger changes the charging potential for charging the photoreceptor.

In one example, a method for calibrating a position of a charge roller is described. The method may include a processor positioning a first end of a charge roller to a first plurality of index positions, determining a capacitance between the charge roller and a photoconductor imaging plate at each of the first plurality of index positions, determining a first index position of the first plurality of index positions with a greatest change in capacitance, and calibrating a position of the charge roller based upon the first index position.

An image forming apparatus includes a photosensitive member, a corona charger including a discharging electrode and a grid electrode having a surface layer containing carbon atoms as a main component and configured to electrically charge the photosensitive member under application of a voltage to the discharging electrode and the grid electrode, and an output portion configured to output information on a lifetime of the grid electrode. The output portion outputs the information on the basis of an index value of an amount of use of the grid electrode correlating with a product of a value of a grid current flowing through the grid electrode and a time of flowing of the grid current through the grid electrode.

An image forming apparatus includes a photoconductor, a charging member, a voltage applier, a rubbing member, a process executor, a current detector, a characteristic deriver and a process controller. The rubbing member is arranged in contact with a surface of the photoconductor to rub the surface. The process executor executes a refresh process of causing the rubbing member to rub the surface for a predetermined time by supplying toner to the rubbing member. The current detector detects a current value of a current flowing from the charging member to the photoconductor. The characteristic deriver derives an electrical characteristic of discharge products adhering to the surface on the basis of an oscillating voltage applied to the charging member by the voltage applier and the current value. The process controller determines whether or not to re-execute the refresh process according to the electrical characteristic when the refresh process is finished.

An image forming apparatus includes a rotatable image bearing member, a developing device including a developing carrying member and configured to develop an electrostatic image formed on the image bearing member with developer, an electrostatic capacity detecting portion configured to detect information on electrostatic capacity between the developer carrying member and the image bearing member, and a toner content detecting portion configured to detect information on a toner content of the developer accommodated in a developing container. On the basis of the detected electrostatic capacity and the detected toner content, a controller controls a driving speed at which the developer carrying member is rotationally driven.