An image forming unit forms an image on a sheet. A first generation circuit generates, regarding a member involved in image formation in the image forming unit, a first signal relating to a first abnormality. A second generation circuit generates, regarding the member, a second signal that relates to a second abnormality different from the first abnormality, and whose feature in a time axis direction or a frequency axis direction is different from that of the first signal. A control circuit has a single port to which the first signal and the second signal are to be input. The control circuit identifies between the first signal and the second signal based on a feature of a signal input to the port.

A charging device for electrically charging rotatable image bearing member includes a corona charger including a discharging wire, a rotatable rotation shaft provided along the discharging wire and provided with a helical groove on an outer peripheral surface thereof, a motor configured to rotate the rotation shaft, a movable member including a projected portion engaging with the helical groove and mounted on the rotation shaft so as to be movable along the rotation shaft with rotation of the rotation shaft, a cleaning member provided on the movable member and configured to clean the discharging wire, and a brush member provided on the movable member and configured to brush the helical groove.

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 image forming unit forms an image on a sheet. A first generation circuit generates, regarding a member involved in image formation in the image forming unit, a first signal relating to a first abnormality. A second generation circuit generates, regarding the member, a second signal that relates to a second abnormality different from the first abnormality, and whose feature in a time axis direction or a frequency axis direction is different from that of the first signal. A control circuit has a single port to which the first signal and the second signal are to be input. The control circuit identifies between the first signal and the second signal based on the feature of a signal input to the port.

Provided is a fixing member having excellent heat resistance and durability. The fixing member includes a substrate and an elastic layer on the substrate, wherein the elastic layer includes: rubber, thermally conductive particles dispersed in the rubber, and iron oxide particles dispersed in the rubber, a content of the thermally conductive particles in the elastic layer is 30% by volume or more and 50% by volume or less, a content of the iron oxide particles in the elastic layer is 0.01% by volume or more and 1.0% by volume or less, the thermally conductive particles are at least one selected from the group consisting of aluminum oxide, metal silicon, magnesium oxide, zinc oxide, and silicon carbide, and the iron oxide particles have a localization index M of 0.2 or more and less than 0.8, wherein the localization index M is determined by specific steps.

An image forming apparatus in which occurrence of an image failure in association with contamination caused by an external additive, such as silica, adhering to a charging unit is suppressed. The image forming apparatus is configured to charge an image bearing member through use of the charging unit, and uses toner having, on a surface thereof, strontium titanate particles and silica particles having predetermined physical properties.

Provided is a fixing member having excellent heat resistance and durability. The fixing member includes a substrate and an elastic layer on the substrate, wherein the elastic layer includes: rubber, thermally conductive particles dispersed in the rubber, and iron oxide particles dispersed in the rubber, a content of the thermally conductive particles in the elastic layer is 30% by volume or more and 50% by volume or less, a content of the iron oxide particles in the elastic layer is 0.01% by volume or more and 1.0% by volume or less, the thermally conductive particles are at least one selected from the group consisting of aluminum oxide, metal silicon, magnesium oxide, zinc oxide, and silicon carbide, and the iron oxide particles have a localization index M of 0.2 or more and less than 0.8, wherein the localization index M is determined by specific steps.

An image forming apparatus includes an image bearing drum; an exposing unit for exposing the drum; an electric circuit board provided substantially perpendicularly to an apparatus installing floor; a driving unit for supplying a driving force; a first metal plate supporting the exposing unit; a second metal plate supporting the electric circuit board; and a third metal plate supporting the driving unit. At least one of the first, second and third plates is provided at each of four sides of the apparatus, the four sides being substantially perpendicular to the floor. The first, second and third plates are electrically connected with each other.

An image forming apparatus has a photosensitive member, a plurality of corona chargers configured to charge the photosensitive member by corona discharge, a plurality of charge output circuits configured to output a charging voltage being applied to each of the corona chargers, a plurality of abnormal discharge detection circuits configured to output an abnormal discharge detection signal according to abnormal discharge occurring in each of the corona chargers, and a controller configured to have a common input port connected to the abnormal discharge detection circuits wherein the abnormal discharge detection signal output from each of the abnormal discharge detection circuits is input to the controller through the common input port. Each of the abnormal discharge detection circuits is connected to a corresponding one circuit out of the charge output circuits.

An electrophotographic member has an electro-conductive substrate, an elastic layer on the substrate and a coating layer on the elastic layer. The elastic layer has an elastic modulus of 0.5 MPa to 3.0 MPa and the coating layer has an elastic modulus of 5.0 MPa to 100.0 MPa as measured in an environment of a temperature of 30 C. and a relative humidity of 80%.