An image forming apparatus, includes an image processing device to perform processing, using electrical power supplied from a supply source, the supply source being selected from it commercial power supply, a first electrical power storage device, and a second electrical power storage device, the second electric power supply storage device supplying electric power in an amount smaller than an amount supplied from the first electric power supply storage device; and circuitry to control the processing to be performed by the image processing device according to the selected supply source. When the supply source is the first electrical power storage device, the circuitry controls the image processing device to execute processing that is executable when the supply source is the commercial power supply. When the supply source is the second electrical power storage device, the circuitry controls the image processing device to execute a part of the processing that is executable when the supply source is the commercial power supply.

An image forming apparatus provided with a charging member to charge a surface of a photoreceptor, includes: a power supply that applies to the charging member a first bias in which an AC voltage is superimposed on a DC voltage or a second bias which is a simple DC voltage; and a hardware processor that causes the power supply to apply the first bias until an amount used of the photoreceptor reaches a predetermined value, and causes the power supply to apply the second bias when the amount used of the photoreceptor reaches the predetermined value.

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.

In a first image formation mode, an image is formed with a first development contrast C1 and a specific dot pattern is formed with a second development contrast C2, which is lower than the first development contrast C1; in a second image formation mode, an image is formed with a third development contrast C3 and a specific dot pattern is formed with a fourth development contrast C4, which is lower than the third development contrast C3; and when C1 (=C2/C1) denotes a ratio between the second development contrast C2 and the first development contrast C1, and C2 (=C4/C3) denotes a ratio between the fourth development contrast C4 and the third development contrast C3, C2<C1 is satisfied.

An image forming apparatus includes a movable photosensitive member, first and second corona chargers, an adjusting mechanism, a developing device, a detecting member configured to detect a surface potential of the photosensitive member at a plurality of positions with respect to the widthwise direction of the photosensitive member, an input portion, and a display portion. In accordance with input of an instruction to the input portion, the detecting portion detects at least two surface potentials of three surface potentials including the surface potential of the photosensitive member after being charged by the first and second corona chargers, the surface potential of the photosensitive member after being charged by the first corona charger, and the surface potential of the photosensitive member after being charged by the second corona charger. A detection result of the detecting member is displayed at the display portion.

An image forming apparatus includes a control unit configured to change, to a light quantity different from a plurality of reference light quantities, a light quantity per unit area of a surface of an electrical charge retention layer of a photosensitive member when an exposure unit exposes the surface in correspondence with a plurality of gradation levels, based on a plurality of exposure potentials corresponding to the plurality of gradation levels which is acquired by exposing with the exposure unit the surface with each of the plurality of reference light quantities corresponding to the plurality of gradation levels, and measuring with the measurement unit the plurality of exposure potentials of the photosensitive member which is formed by the exposure with the plurality of reference light quantities.

An image forming device that forms an image by transferring a toner image formed by developing an 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 exhaust duct to guide air inside the image forming apparatus to an outside of the image forming apparatus. A positive ion generator emits a positive ion into the exhaust duct. A negative ion generator emits a negative ion into the exhaust duct. The negative ion generator is shifted from the positive ion generator in one of an air flow direction of the air moving inside the exhaust duct and a direction perpendicular to the air flow direction.

The image forming apparatus includes an image bearing member, a developing unit for developing an electrostatic latent image formed on the image bearing member with toner, a cartridge that is detachably provided in an apparatus main body and that has at least the developing unit, a toner container that is detachably provided in the apparatus main body and that stores toner for supplying to the developing unit, a memory unit that stores information relating to a usage state of the cartridge, a measuring unit that measures an amount of toner in the developing unit, and a determination unit that determines the amount of toner in the developing unit based on information stored in the memory unit, information obtained by measurement by the measuring unit, and a measurement error of the measuring unit, at a time of an initial operation before performing an image forming operation.

In one example, a method for calibrating a position of a charge roller is described. The method may include a processor positioning a first end of a charge roller to a first plurality of index positions, determining a capacitance between the charge roller and a photoconductor imaging plate at each of the first plurality of index positions, determining a first index position of the first plurality of index positions with a greatest change in capacitance, and calibrating a position of the charge roller based upon the first index position.