In accordance with an embodiment, an image forming apparatus comprises a housing, an image forming section, a temperature sensor, a determination section and a controller. The image forming section has a photoconductive drum and a charging roller for forming an image on a sheet which are arranged in the housing. The temperature sensor measures a temperature in the housing. The determination section determines whether or not the temperature meets a predetermined temperature. The controller carries out an image forming processing by controlling the image forming section if it is determined that a determination result by the determination section meets the predetermined temperature.

Provided is a charging roll for an electrophotographic device in which charge capability is increased and uniformity of charging is satisfied. A charging roll for an electrophotographic device, the charging roll being provided with a shaft body, an elastic body layer formed on the outer periphery of the shaft body, and a surface layer formed on the outer periphery of the elastic body layer, the surface layer containing a binder resin, large-diameter particles having an average particle diameter of 15-50 m, and small-diameter particles having an average particle diameter of 3 m or more and less than 15 m, the content of the small-diameter particles being within the range of 5-50 parts by mass with respect to 100 parts by mass of the binder resin, and the size of particle aggregates including the small-diameter particles contained in the surface layer being 6-50 m.

A toner according to an embodiment includes: a toner base particle that includes a binder that contains polyester resin; and an external additive externally added to the toner base particle. A difference obtained by subtracting a specific surface area of the toner after removal of the external additive from a specific surface area of the toner before removal of the external additive is 0.75 m.sup.2/g or more and less than 1.00 m.sup.2/g.

A conductive member includes: a substrate; an elastic layer provided on the substrate; and a surface layer provided on the elastic layer, in which the surface layer contains a conductive agent and has a sea/island structure that includes a sea portion containing a first resin and an island portion containing a second resin, and an average length of connected island portions in observation of a cross-section of the surface layer is 2.0 ?m or more and 4.5 ?m or less.

A conductive member includes: a substrate; an elastic layer provided on the substrate; and a surface layer provided on the elastic layer, in which the surface layer contains a conductive agent and has a sea/island structure that includes a sea portion containing a first resin and an island portion containing a second resin, and an average length of connected island portions in observation of a cross-section of the surface layer is 2.0 ?m or more and 4.5 ?m or less.

An image forming apparatus includes: a photosensitive member; a power supply that applies a bias voltage to the photosensitive member to charge a surface of the photosensitive member; a developer that develops an electrostatic latent image on the photosensitive member; an exposing device that forms the electrostatic latent image on the photosensitive member; a hardware processor; and a memory, wherein the memory stores, in advance, a relationship between a suitable AC voltage at which a discharge amount of AC electric discharge is balanced between positive and negative sides and a current value of a specific AC voltage, and the hardware processor controls the bias voltage in an AC charging type, detects the current value at the specific AC voltage, and determines a setting AC voltage on the basis of the relationship.

An electrophotographic roller includes an electro-conductive shaft core including a metallic layer at its surface, and an elastic layer on the shaft core. When kinetic friction coefficients of an outer peripheral surface of each end portion of the shaft core with respect to polyester resin are measured for one rotation of the shaft core, an average value pr of the kinetic friction coefficients is 0.05 to 0.50. When each outer peripheral surface is divided into three equal ranges, defined as a region A1, a region A2, and a region A3, in a peripheral direction of the shaft core, each of the regions has a location where the kinetic friction coefficients fall within a range of 1.5 r to 1.8 r, and a location where the kinetic friction coefficients fall within a range of 0.2 r to 0.5 r.

An image forming apparatus includes a controller. The controller controls to perform a first operation in which a first potential difference is formed between a supplying member and a developing member, the first potential difference being a potential difference in a direction in which an electrostatic force in a first direction toward the developing member from the supplying member is acted on toner charged to a normal polarity, and a second operation in which a second potential difference is formed between them and in a second direction opposite to the first direction. When an image forming operation is performed, the controller controls timing for changing from the first operation to the second operation based on information on presence or absence of a recording material in a conveyance passage toward a transferring portion in a non-image forming operation before the recording material is nipped and conveyed at the transferring portion.

An image forming apparatus for electrifying a surface of a photoreceptor with the use of an electrification member includes: a first output unit configured to output a first AC voltage; a second output unit configured to output a second AC voltage having the same frequency as a frequency of the first AC voltage and having a phase different from a phase of the first AC voltage; a superimposition unit configured to superimpose, on a DC component, an AC component containing at least one of the first AC voltage and the second AC voltage; and an application unit configured to apply a voltage that has been subjected to superimposition by the superimposition unit to the electrification member, wherein the superimposition unit changes the AC component to be superimposed on the DC component at a predetermined timing.

A charging member includes a support member, a conductive elastic layer disposed on the support member, and a front surface layer disposed on the conductive elastic layer. Irregularities with a cycle of shorter than 0.1 mm and irregularities with a cycle of 0.1 mm or longer are distributed on an entirety of an outer circumferential surface of the charging member, and satisfy the following conditions of (1) and (2): (1) the irregularities with the cycle of shorter than 0.1 mm have an average height of greater than 0 m and 4 m or less; and (2) the irregularities with the cycle of 0.1 mm or longer have an average height of from 5 m to 30 m. A half-value width of a maximum frequency value of height distribution on the outer circumferential surface is from 1 m to 3 m.