In one example, a method is described that includes a processor detecting a voltage of a photoconductor layer of a printing device, comparing the voltage of the photoconductor layer to a threshold voltage, and applying a corrective voltage to a charging unit or to a transfer member when the voltage of the photoconductor layer exceeds the threshold voltage.

An image forming apparatus includes a photosensitive member, a charging member, an exposing device, a developing device, a transfer member, a brush, a voltage applying portion, and a control portion controlling a surface potential of the photosensitive member at the brush contacting position. When a value of subtracting a value of the surface potential of the photosensitive member in the brush contacting position from a value of the brush voltage is defined as a contacting position potential difference, the control portion controls the surface potential of the photosensitive member in the brush contacting position so that the contacting position potential difference is changed from a first potential difference to a second potential difference in a predetermined direction which is either one of an increasing direction or a decreasing direction, and then the contacting position potential difference is changed from the second potential difference to a third potential difference in the predetermined direction.

An image forming apparatus includes an image bearing member, a developing apparatus, a developer accommodating container, a density detecting portion, and, an execution unit. The density detecting portion configured to output an output voltage corresponding to a toner density in the developer container if a control voltage is applied to the density detecting portion. The execution unit configured to execute a mode if an initial setting of the density detecting portion is performed in the state where the developer accommodating container is attached to the image forming apparatus at an attachment position in an initial installation of the image forming apparatus. In the mode, the execution unit sets a preset control voltage as the control voltage to be applied to the density detecting portion when an image is formed.

A developing device for forming an image by developing an electrostatic latent image formed on an image carrier with a developer, includes: a developing container that accommodates the developer; a developing roller that faces the image carrier, is disposed adjacent to the developing container, and conveys the developer accommodated in the developing container to the image carrier, and a developer discharging part that is provided in the developing container and discharges a part of the developer, wherein a discharge amount of the developer discharged by the developer discharging part is controlled on the basis of a charge amount of a toner included in the developer.

An image forming apparatus includes an image former and a hardware processor. The image former includes, an image carrier; a developer; a conductive rotating member; and a voltage applier which applies voltage to the rotating member. The hardware processor executes an attached material detection mode which detects material attached to a surface of the rotating member. In such mode, the hardware processor controls the voltage so that the developing bias is a value between a surface potential in a region of the image carrier in contact with a portion in which attached material exists on a surface of the rotating member if a reference voltage is applied by the voltage applier, and a surface potential in a region of the image carrier in contact with a portion in which the attached material does not exist on the surface of the rotating member if the reference voltage is applied.

An image forming apparatus includes: a photoreceptor; a transferer; a remover that removes toner on a surface of the photoreceptor; and a hardware processor that: performs a control to form a toner image based on a print image on paper according to a first formation condition by using at least the photoreceptor and the transferer; performs a control to form a toner patch on the surface of the photoreceptor according to a second formation condition determined on the basis of the first formation condition at the time of forming the toner image on the paper by the hardware processor; and controls a voltage applied to the transferer to be a voltage at which the toner patch formed on the photoreceptor is not transferred when the toner patch formed on the surface of the photoreceptor passes through a region facing the transferer.

In an example, a method includes charging a photoconductive surface in a print apparatus and monitoring an electrical parameter associated with a proximity of a print apparatus component to the photoconductive surface. A relative spacing between the print apparatus component and the photoconductive surface may be changed and a contact between the print apparatus component and the photoconductive surface may be detected when the electrical parameter meets predetermined criteria.

An image forming apparatus includes: a capacitance detector that detects capacitance of an opposing member disposed opposite to a photoconductor, wherein the capacitance detector detects the capacitance of the opposing member, based on a result of measurement of a current flowing due to potential difference between a voltage applied to the opposing member and the photoconductor being charged.

An image forming apparatus calculates a post exposure potential after exposure by an exposure device based on a first charge voltage, a second charge voltage, a charge current in a first change characteristic when a transfer voltage is the first charge voltage, a charge current in a second change characteristic when the charge voltage is the first charge voltage, a charge current in the first change characteristic when the charge voltage is the second charge voltage, and a charge current in the second change characteristic when the charge voltage is the second charge voltage, and makes a determination as to life of an image carrier based on the post exposure potential.

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.