A detection apparatus has an alternating-current voltage input unit and a generation circuit. The generation circuit generates a superimposition signal in which information indicating a timing of a zero cross in an alternating-current voltage inputted into the input unit and information indicating a voltage level of the alternating-current voltage are superimposed.

An image forming apparatus includes: a photosensitive drum for bearing a developer; a charging roller that comes into contact with the photosensitive drum at a different velocity and that charges the photosensitive drum; a transfer roller that transfers a developer image on the photosensitive drum to a recording material; a developing sleeve that supplies a developer to the photosensitive drum and that recovers a developer on the photosensitive drum after transfer; detecting device for detecting information relating to injection charging; and a controller that, based on the information, controls an amount of a fogging developer, wherein the controller controls the amount of the fogging developer during image formation according to information detected by the detecting device while suppressing the amount of the developer recovered in the developing sleeve.

An image forming apparatus includes an image bearing member, an intermediary transfer belt, a primary transfer roller provided so that a contact region between the roller and the belt and a contact region between the image bearing member and the belt are in a non-overlapping state with each other with respect to a movement direction of the belt, a primary transfer voltage source, a current detecting portion, an executing portion configured to acquire information on a discharge start voltage on the basis of a detection result of the detecting portion in a period other than a period of primary transfer by applying the voltage to the roller and a setting portion configured to set, on the basis of an execution result of the executing portion, a primary transfer voltage applied to the roller by the primary transfer voltage source in the period of the primary transfer.

An image forming apparatus that forms an image on a transfer material in an image forming mode, includes: a photoreceptor rotatable in a predetermined rotation direction; a developer that forms a toner image on the photoreceptor using a two-component developing agent including toner and a carrier; a transferor that transfers the toner image on the photoreceptor onto the transfer material; a carrier collector that applies an electric field corresponding to a collecting bias to a carrier adhering to the photoreceptor to collect the carrier; a carrier detector that detects a carrier remaining on the photoreceptor after collecting the carrier by the carrier collector; and a hardware processor that sets the collecting bias in the image forming mode on the basis of the amount of carriers detected by the carrier detector when a carrier adhesion detecting mode for forcibly causing a carrier to adhere to the photoreceptor is executed.

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 apparatus includes an image-carrying component configured to carry a colorant image including an adjustment image, a transferring component having a recess in an outer peripheral surface and configured to transfer the colorant image from the image-carrying component to a recording medium in a transfer area while rotating in such a manner as to allow a retainer that is retaining the recording medium to pass through the recess, an image-forming component configured to form the adjustment image at such a position of the image-carrying component as to face the recess of the transferring component, and a transporting component configured to cause the recording medium retained by the retainer to pass through the transfer area.

A print apparatus is disclosed. In an example, the print apparatus comprises: a photoconductive surface to receive a latent image representative of an image to be printed onto a printable substrate; a plurality of print components, each print component having a surface movable relative to the photoconductive surface, wherein a current or voltage is to be applied between the print component surface and the photoconductive surface; and processing circuitry to: measure a current or voltage between each print component surface and the photoconductive surface; responsive to detecting a deviation in the measured current or voltage from a reference current or voltage in respect of any of the plurality of print components, determine that there exists a defect associated with the photoconductive surface; and determine, based on the amount of deviation of the measured current or voltage from the reference current or voltage, an indication of the size of the defect.

An image forming apparatus includes a high-voltage generating circuit which applies to a charging member an oscillation voltage in which a DC voltage and an AC voltage are superimposed, a voltage controller which controls the DC voltage and a peak-to-peak voltage value Vpp of the AC voltage, and a current detector which detects a DC current value Idc between the charging member and an image carrier. The voltage controller detects an Idc(O) when an oscillation voltage having a Vpp(O) at an intersection point of a straight line L1 passing through coordinates A(Vpp(A), Idc(A)) and coordinates B(Vpp(B), Idc(B)) and a straight line passing through coordinates C(Vpp(C), Idc(C)) and parallel to a coordinate axis representing Vpp. Vpp(O) at an intersection point O of a straight line L2 passing through coordinates C and coordinates O(Vpp(O), Idc(O)) and the straight line L1 is determined as an appropriate peak-to-peak voltage value.

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 apparatus includes a photoconductor, a charger, an exposure device, a transfer device, a first and a second surface voltmeter, and a processor. At the first rotation of the photoconductor, the charger charges a charge area on the photoconductor, the exposure device exposes a part of an exposure area in an axial direction of the photoconductor, and the transfer device charges an exposed and unexposed area. At the second rotation, the charger charges the charge area, and the exposure device exposes the exposed and unexposed area at the first rotation. After the exposure at the second rotation, the first surface voltmeter measures a surface potential V1 of the unexposed area at the first rotation, and the second surface voltmeter measures a surface potential V2 of the exposed area at the first rotation. The processor evaluates a life of the photoconductor based on the surface potentials V1 and V2.