An image forming apparatus includes a correction unit configure to correct image data based on a correction condition; an image bearing member; an image forming unit configured to form an image on the image bearing member, based on the corrected image data; a transfer unit configured to transfer the image onto a recording material; a measurement unit configured to measure a measurement image formed on the image bearing member; and a converting unit configured to convert, based on a conversion condition, a measurement result of the measurement image measured by the measurement unit.

A printer controller controls the image forming unit to form the measurement image, control the measurement unit to measure the measurement image, control the converting unit to convert the measurement result of the measurement image, and generate the correction condition based on the measurement result converted by the converting unit.

An image forming apparatus includes a potential applier, a cleaning device and a hardware processor. The cleaning device includes an abutting member abutting a surface of the image carrier and removes residual toner on the surface of the image carrier by means of the abutting member after a toner image formed on the surface of the image carrier is transferred to a transfer material. In a cleaning mode for removing a foreign matter attached to the abutting member of the cleaning device, the hardware processor controls the potential applier to alternately apply a first potential and a second potential which is lower than the first potential to the image carrier so as to periodically change a potential of the abutting member without causing saturation.

An image forming device that forms image by transferring toner image formed by developing electrostatic latent image formed on a photoreceptor from the photoreceptor to an intermediate transfer body by applying a transfer bias to a transfer member and putting the transfer member in contact with the intermediate transfer body. The device includes: a current supplier selectively supplying a first constant current and a second constant current to the transfer member; a first voltage acquirer acquiring a first voltage occurring between the transfer member and the intermediate transfer body while the transfer member is supplied with the first constant current; a second voltage acquirer acquiring a second voltage occurring between the transfer member and the photoreceptor while the transfer member is supplied with the second constant current; and a thickness acquirer acquiring a value indicating photoreceptor layer thickness of the photoreceptor by using the first and second voltages.

An image forming apparatus includes an image forming portion, an image bearing member, a transfer member, a voltage applying portion, a detecting portion, and a controller capable of executing an operation in an adjustment mode in which a chart on which a plurality of test images are transferred by stepwise changing a test voltage applied to the transfer member by the applying portion is formed on a recording material and then a transfer voltage applied to the transfer member applied by the voltage applying portion during transfer of the toner image is adjusted. The controller is capable of changing a change width per level of the test voltage applied during formation of the chart, on the basis of a detection result of the detecting portion when the voltage is applied to the transfer member when the recording material on which the chart is formed is in the transfer portion.

According to at least one embodiment, an image forming apparatus includes a voltage measuring device, a fixing device, and a controller. The voltage measuring device measures an input voltage. The fixing device includes a heater that heats a sheet. When the measured voltage becomes equal to or greater than a threshold value, the controller determines a heating timing of the heater based on the voltage and activates the heater at the determined heating timing.

An image forming apparatus includes a potential detection portion that determines a surface potential of an image bearing member on the basis of an applied voltage value of a detection voltage applied to a voltage application member by a voltage application portion and a detected current value detected by a current detection portion in response to the applied voltage, and a control unit that sets an image formation condition for performing image formation in order to form a toner image on the image bearing member on the basis of the surface potential determined by the potential detection portion. When the surface potential is determined by the potential detection portion, the voltage application portion applies the detection voltage after applying, to the voltage application member, a voltage having an opposite polarity to an image formation voltage that is applied to the voltage application member during image formation.

An image forming apparatus includes an image forming device, an electric current detector, and a controller. The image forming device includes a latent image bearer, a charging rotator, a charging power supply, a latent image writing unit, and a developing unit. The controller (i) determines an uneven electric resistance of the charging rotator in a direction of rotation of the charging rotator, based on a detection result by the electric current detector, (ii) perform, at a predetermined timing, data construction processing to construct change pattern data to change an output value of a voltage from the charging power supply according to a predetermined pattern, based on the uneven electric resistance, and (iii) perform, in a print job to form a toner image in response to an instruction, voltage changing processing to charge the latent image bearer while changing the output value of the voltage, based on the change pattern data.

An image forming apparatus includes a rotatable image bearing member; a developing device including a rotatable developer carrying member, a toner content detecting portion, an electrostatic capacity detecting portion, and a switching portion configured to switch a developing condition on the basis of an output of the toner content detecting portion and an output of the electrostatic capacity detecting portion so that the developing condition is changed when the electrostatic capacity detected by the electrostatic capacity detecting portion reaches first electrostatic capacity at a first toner ratio and so that the developing condition is changed when the electrostatic capacity reaches second electrostatic capacity larger than the first electrostatic capacity at a second toner ratio smaller than the first toner ratio.

A discharging light quantity adjusting device includes a potential measurement controller that performs: a process of causing a first toner image forming process to charge an image holding member to a first potential and an electrometer to measure an electrostatic potential on the image holding member to obtain a first value, a process of causing a second toner image forming process to charge the image holding member to a second potential and removing a toner image formed by the second toner image forming process, and a process of causing a third toner image forming process to charge the image holding member to a third potential, and causing the electrometer to measure an electrostatic potential on the image holding member to obtain a second value; and a light quantity adjusting unit that adjusts a quantity of a discharging light based on the first and second values.

An image forming apparatus includes a photosensitive member, a charging member, an exposure member, a rotatable developer carrying member, a voltage source, and a controller configured to control the voltage source so that when a humidity of an inside of the apparatus is a first humidity, a developing bias voltage including an oscillating portion having an oscillating voltage and a rest portion having a substantially constant voltage are alternately repeated is outputted and so that when the humidity of the inside of the apparatus is a second humidity lower than the first humidity, a developing bias voltage in which the rest portion is not included or is shorter than the rest portion when the humidity of the inside of the apparatus is the first humidity.