A charging device includes a first charging unit and a second charging unit. The first charging unit electrostatically charges a surface of an image bearing member that comes into contact with a medium onto which an image is to be ultimately transferred. The first charging unit is disposed in correspondence with an entire region of the image bearing member in a first scanning direction. The second charging unit is disposed in an overlapping region where a non-passing region of a small-width medium and a passing region of a maximum-usable-width medium overlap when viewed in the first scanning direction. The small-width medium has a width smaller than a maximum usable width of the maximum-usable-width medium. The second charging unit electrostatically charges the overlapping region.

A fixing device includes a heating body, a pressuring body, a heating source, a guiding part, a temperature sensing part and a charging part. The heating source supplies the heating body heat used for heating the medium. The guiding part guides the medium to a nip between the heating body and the pressuring body, at an upstream side from the nip in a conveying direction of the medium. The temperature sensing part senses a temperature of the heating body. The charging part electrically discharges to electrically charge the heating body with the same polarity as toner, at an opposite side to the guiding part across the temperature sensing part. The charging part includes a discharging electrode electrically discharging toward the heating body facing to the discharging electrode and an enclosure wall supporting the discharging electrode, enclosing the discharging electrode and producing an electric field in cooperation with the discharging electrode.

A photosensitive drum is rotatable about a first axis extending in a particular direction. A frame rotatably supports the photosensitive drum. A developing roller is rotatable according to driving force about a second axis extending in the particular direction. A surface of the developing roller contacts a surface of the photosensitive drum through toner. A resistance generating member generates a resistance torque TQ1 serving as resistance between the frame and photosensitive drum in a case where the photosensitive drum rotates relative to the frame. In a case where the developing roller rotates according to the driving force in a state where the surface of the developing roller contacts the surface of the photosensitive drum through toner, the resistance torque TQ1 is smaller than a torque TQ2 that causes the photosensitive drum to rotate due to friction between the surface of the developing roller and the surface of the photosensitive drum.

According to one embodiment, a charger charges a surface of an image carrier by discharge in a wide-angle. A charging bias voltage application section applies a charging bias voltage to the charger. An exposing device forms an electrostatic latent image in a charged image carrier. A toner carrier causes toner to adhere to the electrostatic latent image formed in the image carrier. A developing bias voltage application section applies the developing bias voltage to the toner carrier. In addition, the developing bias voltage application section changes the charging bias voltage in one step and changes the developing bias voltage applied to the toner carrier in multiple steps.

According to one embodiment, a charger charges a surface of an image carrier by discharge in a wide-angle. A charging bias voltage application section applies a charging bias voltage to the charger. An exposing device forms an electrostatic latent image in a charged image carrier. A toner carrier causes toner to adhere to the electrostatic latent image formed in the image carrier. A developing bias voltage application section applies the developing bias voltage to the toner carrier. In addition, the developing bias voltage application section changes the charging bias voltage in one step and changes the developing bias voltage applied to the toner carrier in multiple steps.

A corona discharge device including a corona electrode provided with multiple sharpened tip portions in a row includes a cleaning member which cleans the tip portions of the corona electrode while reciprocating along a predetermined movement direction set in advance with the tip portions biting into the cleaning member. A cleaning position at a surface of the cleaning member is different in a direction intersecting a longitudinal direction of the corona electrode between when the cleaning member moves toward one side in the movement direction and when the cleaning member moves toward another side in the movement direction.

A corona discharger includes a discharge wire and holding portions for holding the discharge wire at longitudinal opposite end portions thereof. The discharge wire comprises a base material of metal, and a surface layer of the material comprises carbon on a part thereof. The discharge wire includes a coated region coated with the surface layer, and non-coated regions at opposite sides of the coated region with respect to the longitudinal direction of the discharge wire. Opposite end portions of the discharge wire are in the non-coated regions.

Partial discharges in a high voltage electric machine can be monitored by a partial discharge monitor connected to the high voltage electric machine successively via a capacitive coupler and a connection cable. The connection cable can have a conductive element designed to self-destruct in the presence of electric current amplitude significantly exceeding expected current amplitudes from said partial discharges, and having diameter designed to avoid creation of additional partial discharges within the cable itself. The connection cable can be light enough to avoid adding excessive weight to the stator windings.

An electrophotographic imaging device includes a charging device, a cleaning device, and a fuser member that each include hydrophobic carbon nanotubes. The use of hydrophobic carbon nanotubes can increases the charging device's, the cleaning device's, and the fuser member's durability, conductivity, and contaminants deposition.

An image forming apparatus includes a corona charger including a discharging wire, a grid electrode, for charging a photosensitive drum at a charging position; and an exposure device for exposing the drum charged by the charger at an exposure position which is in a downstream side of the charger in a rotational direction of the drum at the charging position. The grid electrode includes a first portion having openings and a second portion having only a non-opening portion in a charging region for charging the drum in a longitudinal direction of the charger, and the second portion includes a downstream side peripheral portion at a downstream end of the grid electrode with respect to the rotational direction. In a cross-section orthogonal to the longitudinal direction and including the charging region, the downstream side peripheral portion is intersected by a straight line passing through the exposure position and the wire.