A charger includes a roller-shaped charging member and a contact width varying device. The charging member is in contact with a surface of an image holding member so as to charge the surface of the image holding member. The contact width varying device varies in an axial direction of the image holding member a contact width of the charging member with the image holding member so as to decrease uneven wear occurring in the axial direction of the image holding member.

An image forming apparatus including: a charging member configured to charge a photosensitive member at a charging portion by a charging voltage in which an alternate-current voltage is superimposed on a direct-current voltage; a transfer member configured to transfer a toner image formed on the photosensitive member to a recording material at a transfer portion; and a controller configured to control the charging voltage, a predetermined area of the photosensitive member passing through the transfer portion during a trailing edge of the recording material passing through the transfer portion, wherein the controller controls a value of a peak-to-peak voltage of the alternate-current voltage when the predetermined area passes through the charging portion to be larger than a value of a peak-to-peak voltage when an area that becomes the image area other than the predetermined area passes through the charging portion.

An image forming apparatus includes: an acquisition portion that acquires, based on a current value detected by a detection unit, a discharge start voltage value between a photosensitive body and a charging member, in a voltage value of a voltage applied to the charging member, the discharge start voltage value being acquired from at least one of a plurality of measurement regions set by dividing an image forming region of the photosensitive body, in which an electrostatic image is formed, into a plurality of regions in a longitudinal direction orthogonal to a recording material conveyance direction; and a control portion that performs unevenness suppression control to reduce unevenness, in the longitudinal direction, of density of a developer image transferred onto the recording material based on the discharge start voltage value.

A discharging method used in an image forming apparatus includes discharging, with an exposure device, an exposure range of the latent image bearer, and discharging, with a discharger, an area of the latent image bearer outside the exposure range and inside a developing range in a main scanning direction. The exposure range is inside the developing range in the main scanning direction. The discharging with the exposure device and the discharging with the discharger are performed when a rotation of the latent image bearer is stopped after a toner image is transferred from the latent image bearer.

In an image forming apparatus, the image bearing member has a surface and configured to rotate about an axis. The collection device is in contact with the surface, and configured to collect materials adhered to the surface. The developing roller is configured to provide a charged toner having a first polarity. The processor is configured to perform: executing a print job in a printing period; executing, in a non-printing period, a first process in which the image bearing member is rotated at least one rotation while a holding bias is applied to the collection device, the holding bias having a second polarity opposite to the first polarity; and executing, in a non-printing period after the first process, a second process in which the image bearing member is rotated while an ejection bias is applied to the collection device, the ejection bias having the first polarity.

An image forming apparatus includes: a photoconductor; an electric charging device charging the photoconductor; an exposure device exposing a portion of the photoconductor charged by the electric charging device to light based on image information, to form an electrostatic latent image; a first charge eliminating device emitting light to the photoconductor so as to eliminate an electric charge on a surface of the photoconductor; a second charge eliminating device emitting light to the photoconductor so as to eliminate an electric charge on a surface of the photoconductor, a wavelength of the light emitted by the first charge eliminating device being different from a wavelength of the light emitted by the second charge eliminating device; and a controller selectively operating the first and second charge eliminating devices depending on an image content of the electrostatic latent image in an image forming process.

An image forming apparatus includes first and second image forming portions, a power source portion, and a controller. The power source portion is constituted so that when the power source portion applies a charging voltage to a first charging member of the first image forming portion, the charging voltage is also applied to a second charging member of the second image forming portion. The controller carries out control so that a timing of a start of discharge of a first photosensitive drum in the first image forming portion is made earlier than a timing of a start of image formation by the first image forming portion and so that a timing of a start of discharge of a second photosensitive drum in the second image forming portion is made earlier than a timing of a start of image formation by the second image forming portion.

An image forming apparatus includes a first image forming portion, a second image forming portion, a power source portion, and a controller. The power source portion is constituted so that when the power source portion applies a charging voltage to a first charging member of the first image forming portion, the charging voltage is also applied to a second charging member of the second image forming portion. The controller carries out control so that an emitted light quantity of a light emitting element is changed from a first light quantity to a second light quantity larger than the first light quantity and is changed from the second light quantity to a third light quantity larger than the second light quantity.

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.