An image forming apparatus includes a photosensitive member unit, a charging member, an exposing unit, a developing unit, an information storage portion, and a setting portion. The information storage portion stores information on an attenuation amount of a surface potential of the photosensitive member by which the surface potential is attenuating until the photosensitive member rotates from a contact position of the photosensitive member to a development position of the photosensitive member. If the attenuation amount is a first attenuation amount, the setting portion sets an applying voltage to be applied to the charging member at the time of image formation to a first voltage. If the attenuation amount is a second attenuation amount larger than the first attenuation amount, the setting portion sets an applying voltage to be applied to the charging member at the time of image formation to a second voltage larger than the first voltage.

An image forming apparatus includes: an image carrier; a charging roller that charges the image carrier; a power supply part that applies a charging voltage to the charging roller; a current measurement part that measures a value of a DC component of a current flowing between the image carrier and the charging roller at at least two timings having mutually different elapsed times; and a hardware processor that measures an elapsed time from a start of application of the charging voltage by the power supply part, calculates a coefficient of an approximate expression indicating a relationship between the value of the DC component of the current flowing between the image carrier and the charging roller, and the elapsed time, and performs judgment related to life of the charging roller on the basis of the coefficient and a predetermined threshold.

An example method of determining dot gain in a liquid electrophotographic printer is described. The method involves effecting a print operation based on a predetermined digital dot area and measuring an operating current of a binary ink development unit during the print operation. A dot gain between the digital dot area and a physical dot area of a developed image is determined based on a function of the measured operating current.

A control portion executes: a step of calculating a surface potential of an image bearing member charged by a charging member, to which a predetermined voltage is applied, and exposed to light by a predetermined exposure amount on the basis of a discharge start voltage between a measurement member and the image bearing member and calculating a correction value from a difference between a target value and calculated surface potential of the image bearing member; a step of correcting calculated surface potential of the image bearing member on the basis of the correction value; and a step of controlling at least one of the voltage applied to the charging member and an exposure amount of the exposure apparatus on the basis of the corrected surface potential of the image bearing member so that the surface potential of the image bearing member reaches the target value.

In an example, a method of operating a liquid electrophotographic printer is described. The method involves applying limits to a printer control signal. In particular, the printer control signal is digitally processed to reduce signal values to within the obtained limits, wherein neighboring values are modified to maintain the total energy of the printer control signal. The liquid electrophotographic printer is controlled using the processed printer control signal.

An image forming apparatus includes a rotatable photoconductor, a charging device, a voltage applying device, a current detection device, and control circuitry. The control circuitry is configured to determine a film thickness of the photoconductor based on a charging current detected with the current detection device; determine an estimated film thickness of the film thickness, based on a previous film thickness and travel information of the photoconductor after determination of the previous film thickness; determine a discharging start voltage that the voltage applying device applies to start discharging from the charging device to the photoconductor; determine, from the estimated film thickness and the discharging start voltage, a film thickness determining voltage that the voltage applying device applies to pass a film thickness determining current being a charging current used for determining the film thickness; and apply the film thickness determining voltage to the charging device to determine the film thickness.

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.

According to at least one embodiment, an image forming apparatus includes a heater and a controller. The heater is configured to generate heat. The controller is configured to control AC power to the heater so that a part of the AC power which exceeds a threshold voltage is not applied to the heater.

An image forming apparatus includes an image bearing member, a rotatable endless intermediary transfer belt, an inner roller, an outer roller, a power source, a detecting portion, and a controller. On the basis of a result of detection by the detecting portion when a voltage is applied to the inner roller so as to form a chart on a recording material of a predetermined kind in an operation in an adjusting mode, the controller determines whether a transfer voltage when a toner image is transferred onto the recording material of the predetermined kind is subjected to constant-voltage control so that the voltage applied to the inner roller by the power source becomes a target value or is subjected to constant-current control so that a current supplied to the inner roller becomes a target value.

An image forming apparatus includes a storage unit and a charging amount acquisition unit. The charging amount acquisition unit performs a charging amount acquisition operation for forming a measurement toner image on the image carrier while changing the frequency of the alternating current voltage of the development bias with a potential difference in a direct current voltage between the developing roller and the image carrier being kept constant, acquiring a tilt of a measurement straight line representing a relationship between the change amount of the frequency and a density change amount of the measurement toner image, and acquiring the charging amount of the toner based on the acquired tilt of the measurement straight line and the reference information in the storage unit.