An image forming apparatus includes a photoconductor, a charger, a detection unit, and a determination unit. The charger charges the photoconductor. The detection unit detects an actual charging potential of the photoconductor after the photoconductor is charged by the charger. The determination unit determines one of a plurality of causes related to a charging abnormality of the photoconductor based on a relationship between a standard charging potential of the photoconductor to be obtained by charging by the charger and a charging potential detected by the detection unit.

An image forming apparatus comprises: an image processor to convert image data based on a conversion condition; an image forming unit to form an image based on the converted image data using a replaceable member; a memory to store the image data and the converted image data; a sensor to perform measurement on a test image; and a controller. If the replacement of the replaceable member is detected while forming images, the controller controls the image forming unit to form the test image and generates the conversion condition based on a result of the measurement on the test image. If the replacement of the replaceable member is detected while forming the images, the controller further controls the image processor to convert the image data stored in the memory based on the generated conversion condition.

An image forming apparatus includes: 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.

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 prescribed bias voltage to the development device; and a calculating section which calculates a surface potential of the photosensitive drum based on a development current flowing in the development device. The calculating section calculates, as the surface potential, a bias voltage at which a non-charging development current that flows in the development device in an uncharged state in which the charger has not charged the photosensitive drum is equal to a charging development current that flows in the development device in a charged state in which the charger has charged the photosensitive drum.

An electroconductive elastic body includes: a cross-linked product of a first ionic electro-conductive rubber, a cross-linked product of a second ionic electro-conductive rubber, and at least one of a fatty acid and a fatty acid metal salt; wherein the electroconductive elastic body has a matrix that includes the cross-linked product of the first ionic electro-conductive rubber, and a domain that includes the cross-linked product of the second ionic electro-conductive rubber; the cross-linked product of the second ionic electro-conductive rubber includes a polyether skeleton; an electrical resistance of the domain is lower than an electrical resistance of the matrix; in a waveform separation profile of the elastic body as obtained by a small-angle X-ray scattering method, A2 and A1 satisfy a relationship expressed by the following expression (1):
0.005≤(A2×C2/A1×C1)≤0.030  (1).

A photosensitive member unit includes a photosensitive member, a charging roller, a charging roller bearing member, a gear, a separation member having an engagement portion, a guide portion, and a frame to support the photosensitive member. The guide portion guides the charging roller bearing member urged by a urging member to separate the charging roller from the photosensitive member in a state where the engagement portion and the gear are engaged with each other and guides the charging roller bearing member urged by the urging member so that the charging roller comes into contact with the photosensitive member in a state where the engagement portion and the gear are not engaged. A distance between the urged charging roller bearing member and the frame is less than a length in which the engagement portion and the gear are engaged in the state where the engagement portion and the gear are engaged.

In one example, a device includes a flexible roller and an actuator to flex the roller while it is rotating to change the gap between the roller and a surface opposite the roller.

To provide a conductive roll for an electrophotographic apparatus that includes a conductive rubber elastic body layer having a lower hardness and lower settling properties than a conventional conductive rubber elastic body layer.

A conductive roll 10 for an electrophotographic apparatus includes a shaft body 12, and a conductive rubber elastic body layer 14 provided on the outer periphery of the shaft body 12, the conductive rubber elastic body layer 14 containing polar rubber, non-polar rubber, and a dispersing agent, wherein the polar rubber is at least one of nitrile rubber, hydrin rubber, and chloroprene rubber, wherein the non-polar rubber is at least one of isoprene rubber, hydrogenated isoprene rubber, and natural rubber, and wherein the dispersing agent is at least one of a polymer containing a block made of a nitrile rubber component and a block made of an isoprene rubber component, modified natural rubber, and modified isoprene rubber.

A charging member includes a support, a conductive elastic layer disposed on the support, and a surface layer disposed on the conductive elastic layer. Domains with current values of 2.5 pA or more have an average size of about 300 nm or less in a binary image created using a current value of 2.5 pA as a threshold from current measured by contacting a conical probe having a tip diameter of 20 nm with an outer surface of the surface layer and applying a voltage of 3 V between the conical probe and the support while moving the conical probe.

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.