An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm.sup.2 or more and 3.5 gf/mm.sup.2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.

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.

An image forming apparatus that includes a charger for charging a surface of a photoreceptor and that forms an image by using an electrophotographic system, the charger being configured to be cleanable, includes a guidance notification unit that causes a guidance notification prompting cleaning of the charger to be displayed and a guidance notification determination unit that, in accordance with a threshold set in accordance with usage condition of the image forming apparatus, determines whether or not to cause the guidance notification to be displayed.

An image forming apparatus includes an apparatus body, a photoconductor unit, and a developing cartridge. The apparatus body includes a controller and a body-side contact portion. The photoconductor unit includes a photoconductor, a charger, and a frame body. The developing cartridge includes a developing roller, a storage medium configured to store information, and a cartridge-side contact portion. The photoconductor unit includes a first contact portion configured to be electrically connected to the body-side contact portion, a second contact portion configured to be electrically connected to the cartridge-side contact portion, and a wiring portion electrically connecting the first contact portion and the second contact portion. The photoconductor unit further includes a separating member. The separating member is arranged to separate the charger and the part of the wiring portion when viewed in the rotational axis direction of the photoconductor.

An image forming apparatus comprises a spacing member provided on a rotation shaft of a charging roller, the spacing member configured to include an engaging portion that engages with a rotation member, and to be rotatable between a spaced position at which a spaced state in which a photosensitive drum and the charging roller are spaced apart is maintained, and a released position at which the spaced state is released and the photosensitive drum and the charging roller are caused to be in contact; and a cover portion provided on the rotation shaft of the charging roller, and configured to cover an end face of the spacing member so that a fitting portion of the charging roller and the spacing member is covered.

A charging device (51) includes a charging roller (65), a supporting section (71), a guide (73), a first biasing section (75), and a second biasing section (90). The charging roller (65) charges an image bearing member (50). The supporting section (71) supports the charging roller (65) such that the charging roller (65) is rotatable. The guide (73) guides the supporting section (71) in a first direction (D1). The first biasing section (75) biases the supporting section (71) in the first direction (D1) to press the charging roller (65) against the image bearing member (50). The second biasing section (90) biases the supporting section (71 toward the guide (73).

The present invention includes a compressor for generating compressed air for separating a sheet from a fixing portion. By using the compressed air generated by the compressor, an image forming portion, more specifically, for example, a charger, is cleaned.

An image forming apparatus includes a charging roller and a developing voltage application portion. The charging roller is in contact with a rotating image carrier to charge the image carrier. The developing voltage application portion applies a developing bias voltage including an AC component to a developing roller in a developing portion, when the image carrier is in a rotation state with no image. The rotation state with no image indicates a state in which the charged image carrier rotates with no electrostatic latent image being formed thereon. The developing portion supplies toner containing an external additive to the image carrier.

A charging device includes a charging member, a cleaning member, and first and second support members. The charging member rotates around a rotation shaft and charges of an image holding member. The rotation shaft of the charging member is disposed parallel to a rotation shaft of the image holding member. The cleaning member rotates around a rotation shaft and cleans the charging member. The rotation shaft of the cleaning member is disposed to incline with respect to the rotation shaft of the charging member. The first support member supports one end of the charging member and one end of the cleaning member. The second support member supports the other end of the charging member and the other end of the cleaning member, has the same configuration as a configuration of the first support member, and is disposed symmetrically with the first support member with the charging member interposed therebetween.

An image forming apparatus includes an image forming unit that forms an image by forming an electrostatic latent image on an image carrier, which is charged by a charging member to which a normal voltage is applied, on the basis of image information and by supplying a developer to the image carrier; an application unit that applies a special alternating-current voltage to the charging member, the special alternating-current voltage at least having an amplitude that is greater than that of an alternating-current voltage that is applied when forming the image; and an instruction unit that instructs the application unit to apply the special alternating-current voltage at a specific time in a period other than an image forming period during which the image forming unit forms the image.