An image forming apparatus includes a photoreceptor, a measurer that measures the number of rotations of the photoreceptor, and a hardware processor. The hardware processor predicts a film scraping amount of the photoreceptor on the basis of a measurement result of the measurer and determines a service life of the photoreceptor on the basis of a prediction result of the hardware processor. The hardware processor calculates the film scraping amount by multiplying the number of rotations of the photoreceptor per predetermined time by a predetermined coefficient, and integrates the calculated film scraping amount for each predetermined time. The predetermined coefficient is set to a different value according to the number of rotations of the photoreceptor per predetermined time.

An image forming apparatus includes a photoconductor, a charging roller to charge the photoconductor, a power source to apply a charging bias to the charging roller, a current sensor to generate a feedback signal representing an output current flowing from the charging roller to the photoconductor, a memory, and circuitry. The circuitry calculates film thicknesses of a photoconductor film of the photoconductor at a plurality of points of time based on a voltage of the charging bias and the output current, calculates travel distances of the photoconductor charged at the plurality of points of time, associates the film thicknesses with the travel distances, stores the film thicknesses and the travel distances in the memory, calculates a present estimated film thickness based on the film thicknesses and the travel distances, and calculates an estimated film thickness range corresponding to a present travel distance based on the present estimated film thickness.

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 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 roller to charge the photoconductor, a power source to apply a charging bias to the charging roller, a current sensor to generate a feedback signal representing an output current flowing from the charging roller to the photoconductor, a memory, and circuitry. The circuitry calculates film thicknesses of a photoconductor film of the photoconductor at a plurality of points of time based on a voltage of the charging bias and the output current, calculates travel distances of the photoconductor charged at the plurality of points of time, associates the film thicknesses with the travel distances, stores the film thicknesses and the travel distances in the memory, calculates a present estimated film thickness based on the film thicknesses and the travel distances, and calculates an estimated film thickness range corresponding to a present travel distance based on the present estimated film thickness.

An image forming apparatus includes: a photoreceptor; a measurer that measures the number of rotations of the photoreceptor; and a hardware processor that predicts a film scraping amount of the photoreceptor on the basis of a measurement result of the measurer, and determines a service life of the photoreceptor on the basis of a prediction result of the hardware processor, wherein the hardware processor calculates the film scraping amount by multiplying the number of rotations of the photoreceptor per predetermined time by a predetermined coefficient, and integrates the calculated film scraping amount for each predetermined time, and the predetermined coefficient is set to a different value according to the number of rotations of the photoreceptor per predetermined time.

An image forming apparatus includes an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.

An image forming apparatus includes: an acquisition portion that acquires, based on a current value detected by a detection unit, a discharge start voltage value between a photosensitive body and a charging member, in a voltage value of a voltage applied to the charging member, the discharge start voltage value being acquired from at least one of a plurality of measurement regions set by dividing an image forming region of the photosensitive body, in which an electrostatic image is formed, into a plurality of regions in a longitudinal direction orthogonal to a recording material conveyance direction; and a control portion that performs unevenness suppression control to reduce unevenness, in the longitudinal direction, of density of a developer image transferred onto the recording material based on the discharge start voltage value.

An image forming apparatus includes a photosensitive member, a corona charger including a discharging electrode and a grid electrode having a surface layer containing a carbon atom 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 an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.