An image forming apparatus includes an image forming portion, an image bearing member, a transfer member, a voltage source, a density detecting portion, a display portion, a controller, and an operating portion. The controller is capable of executing an operation in a mode in which a test chart for adjusting a transfer voltage is outputted, and setting information on the transfer voltage set for during transfer on the basis of a detection result when the test chart is detected by the detecting portion is displayed at the display portion and is checked by user. The controller causes the display portion to display setting information on the basis of a correcting value and causes the user to check the setting information in the operation in the mode executed after the correcting value is inputted from the operating portion.

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: a development device which develops an electrostatic latent image formed on a photosensitive drum into a toner image; a charger which charges the photosensitive drum; a development power supply which applies a bias voltage to the development device; a calculating section which calculates a surface potential of the photosensitive drum based on a development current flowing in the development device; and an estimating section which estimates a fogging toner amount. The fogging toner amount is an amount of toner moved due to fogging. When the fogging toner amount estimated by the estimating section is less than a prescribed threshold, the calculating section calculates a value of the bias voltage at which the development current stops flowing as the surface potential.

An image forming apparatus includes a rotatable image bearing member, a charging member, a charging voltage applying portion, a developer carrying member, a developing voltage applying portion, a detecting portion, and a controller. In a state in which the charging voltage is applied to the charging member, the controller controls the detecting portion so as to detect whether or not a change amount between a current value detected by the detecting portion when the surface of the image bearing member opposing the developer carrying member before application of the developing voltage passes through an opposing portion where the charging member and the image bearing member are opposed to each other and a current value detected by the detecting portion when the surface of the image bearing member opposing the developer carrying member after the application of the developing voltage passes through the opposing portion is a threshold or more.

A volt meter and a current meter may measure a voltage and a current for the calculation of power consumption. A controller may calculate the power consumption when a heating element is activated and when the heating element is deactivated. Based on the power consumptions when the heating element is activated or deactivated, a failure condition may be determined.

According to one embodiment, an image forming apparatus includes a photoreceptor, a charging member, an application unit, and a control unit. An image is formed on the photoreceptor. The charging member is in contact with or close to a surface of the photoreceptor. The application unit applies a voltage to the charging member. The control unit performs control so that a current flowing through the charging member and the photoreceptor becomes a constant current when the photoreceptor is in an unused state, measures a voltage when the constant current flows and stores the measured voltage as a reference voltage, and controls the application unit to apply a voltage obtained by adding correction according to a value indicating a usage amount of the photoreceptor to the reference voltage.

An image forming apparatus includes a toner charge amount predictor, a toner developing resistance calculator, and a determiner. The toner developing resistance calculator calculates a toner developing resistance on the basis of a bias voltage applied to a developing device and a measured developing current by dividing a value of the bias voltage by a value of the developing current when a developing device develops an electrostatic latent image formed on the surface of an image carrier to form a toner image. The toner charge amount predictor predicts a toner charge amount of a toner which is supplied to the image carrier by the developing device on the basis of a density of the toner image and the developing current. The determiner determines a state of the developing device on the basis of the toner charge amount and the toner developing resistance.

An image forming apparatus includes an image carrier, a charging device, a developing device, a transfer device, a development power supply, a current measurement device, and a processor. The development power supply applies a predetermined bias voltage to the developing device. The processor functions as a calculator and a controller. The calculator calculates a surface potential of the image carrier based on the development current measured by the current measurement device. The controller controls the charging device, the developing device, the transfer device, and the development power supply. The controller sets a tentative transfer current to be flowed through the transfer device while the calculator calculates the surface potential.

An image forming apparatus includes an image carrier, a developing device, a voltage applier, a current detector, a weight detector, and a control device. The control device acts as a first measurer, a second measurer, and an estimator. The first measurer acquires a toner use amount indicating weight per unit area, of the toner that has migrated from the developing agent carrier to the image carrier, according to a detection result provided by the weight detector. The second measurer acquires the developing current from the current detector. The estimator calculates a value of decision coefficient, obtained by dividing variance of an estimated value in a regression model between the toner use amount and the developing current, by variance of a sample value, and estimates deterioration status of the toner, according to the value of the decision coefficient.

Provided is an image forming apparatus, including: an image holder configured to hold an image formed using an electrographic process; a transfer body that faces the image holder and is configured to contact the image holder while rotating to form a secondary transfer region; an application unit configured to apply a voltage for charging the secondary transfer region; and a charge unit that faces a region other than the secondary transfer region of the transfer body and is configured to charge a surface of the transfer body with a polarity opposite to an applied voltage of the application unit.