An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of the transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is lower than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is less than a volume average particle diameter of the second carrier.

A developer set includes a first developer and a second developer. The first developer includes a first toner and a first carrier. The second developer includes a second toner and a second carrier. The second toner is a toner that includes a flaky brilliant pigment, a toner that includes a white pigment, or a transparent toner. The second carrier has a higher volume resistivity than the first carrier and has a larger volume average particle diameter than the first carrier.

A photosensitive layer of an electrophotographic photosensitive member is a single layer and contains a charge generating material, a binder resin, a first electron transport material, a second electron transport material, and a hole transport material. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4).

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The repeating unit (3) has a percentage content of greater than 0% and less than 50% to a total number of repeats of the repeating units (1) and (3). The repeating unit (4) has a percentage content of at least 35% and less than 70% to a total number of repeats of the repeating units (2) and (4).

A developing device includes a developer carrier that rotates while holding a developer, a developer container that supports the developer carrier and contains the developer, a transport member that is supported in the developer container and that transports the developer by rotating, and a conveying member that is disposed on the transport member and that conveys air in the developer container toward an exhaust port, which enables the air in the developer container to be exhausted outside, along with rotation of the transport member.

An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of the transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is lower than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is less than a volume average particle diameter of the second carrier.

An image forming apparatus includes a toner image bearer, a transfer device, a cleaner, a bias power source, and circuitry. The toner image bearer bears a toner image. The transfer device performs a transfer process The cleaner contacts the toner image bearer to remove transfer residual toner that is subject to the transfer process and remove untransferred toner that is not subject to the transfer process. The bias power source applies one of a first bias and a second bias different from the first bias to the cleaner. The circuitry controls the bias power source to output the first bias to the cleaner in response to a start of an image forming operation to remove the untransferred toner from the toner image bearer and control the bias power source to switch an output from the first bias to the second bias.

There is provided an image forming apparatus including: an intermediate transfer belt; a photosensitive drum; a primary transfer member; a secondary transfer member; a first backup member; a first power supply electrically connected to the primary transfer member and to the secondary transfer member; and a first resistor electrically connected to the first power supply and to the primary transfer member. A first current route, in which the first resistor, the primary transfer member, and the photosensitive drum are connected in series in that order, is connected to the first power supply and to a basis potential. A second current route, in which the secondary transfer member and the first backup member are connected in series, is connected to the first power supply and to the basis potential. The first current route is connected in parallel to the second current route.

In a belt cleaning device, a pivot member supports a first rotation shaft of a cleaning roller in a rotatable manner, and is supported by a second rotation shaft of a collection roller. An elastic member keeps the cleaning roller contact with an endless belt at a position. A first seal portion, fixed to the pivot member, is in contact with the collection roller. A housing has a first space storing the cleaning roller and the collection roller, and a second space storing waste toner rubbed off from the collection roller by a blade. The housing supports the second rotation shaft. The second seal portion is fixed to one of an inner surface of the housing and the pivot member, and is in contact with the other. The blade, the first seal portion, and the second seal portion partition the housing into the first space and the second space.

An embodiment provides an image forming apparatus that has a first operation mode and a second operation mode. The first operation mode forms an image on a sheet with toner. The second operation mode decolorizes the toner on the sheet on which the image is formed with a decolorable toner having a decoloring function. In the first operation mode, when the sheet passes through a transfer unit, a transfer bias having the same polarity as that of a charge of the toner is applied to the transfer member and a toner image formed on a surface of the transfer member is transferred to the sheet. In the second operation mode, when the sheet passes through the transfer unit, a cleaning bias having a reverse polarity to that of the transfer bias is applied to the transfer member.

A developing device includes a developer carrier that rotates while holding a developer, a developer container that supports the developer carrier and contains the developer, a transport member that is supported in the developer container and that transports the developer by rotating, and a conveying member that is disposed on the transport member and that conveys air in the developer container toward an exhaust port, which enables the air in the developer container to be exhausted outside, along with rotation of the transport member.