A drum cartridge includes a first photosensitive drum, a frame, a main body connector, a first toner cartridge connector, a drum-cartridge circuit board, a harness, and a first harness. The harness is electrically connected between the main body connector and the drum-cartridge circuit board. The harness extends in the first direction. The first harness is electrically connected between the first toner cartridge connector and the drum-cartridge circuit board. The first harness extends in the second direction.

An image forming apparatus includes a latent-image forming unit that forms an electrostatic latent image onto an image carrier, a developing member that develops the electrostatic latent image held on the image carrier with a developer, a container that contains the developer supplied to the developing member, a stirring member that stirs the developer by rotating in the container, a density detecting unit that is disposed in the container and that detects a density of the developer, and a switching unit that switches an image formation condition by using a period of a signal output by the density detecting unit.

A drum cartridge includes a first photosensitive drum, a frame, a main body connector, a first toner cartridge connector, a drum-cartridge circuit board, a harness, and a first harness. The harness is electrically connected between the main body connector and the drum-cartridge circuit board. The harness extends in the first direction. The first harness is electrically connected between the first toner cartridge connector and the drum-cartridge circuit board. The first harness extends in the second direction.

A drum cartridge that is mountable to and demountable from a main body of an image forming apparatus, the drum cartridge including: a photosensitive drum rotatable about a first axis extending in a first direction; and a first conveying roller rotatable about a second axis extending in the first direction, the first conveying roller being in contact with a second conveying roller of the image forming apparatus and being configured to convey a sheet, which is sandwiched between the first conveying roller and the second conveying roller, toward the photosensitive drum in a state where the drum cartridge is mounted on the main body, in which the drum cartridge has a guide groove into which an end portion of the second conveying roller in the first direction is inserted in the state where the drum cartridge is mounted on the main body.

A charging device includes: a charging member that is rotatable and has a peripheral surface to be in contact with a charging target and to which a voltage is to be applied for charging the charging target; a removing member that includes a core and a removing material spirally wound one to less than two times around the core and rotates and comes into contact with the charging member to remove an unnecessary material from the peripheral surface of the charging member; and a detecting unit that detects a current flowing between the charging member and the removing member.

A charging device includes: a charging member that is rotatable and has a peripheral surface to be in contact with a charging target and to which a voltage is to be applied for charging the charging target; a removing member that includes a core and a removing material spirally wound one to less than two times around the core and rotates and comes into contact with the charging member to remove an unnecessary material from the peripheral surface of the charging member; and a detecting unit that detects a current flowing between the charging member and the removing member.

A drum cartridge includes a first photosensitive drum, a frame, a main body connector, a first toner cartridge connector, a drum-cartridge circuit board, a harness, and a first harness. The harness is electrically connected between the main body connector and the drum-cartridge circuit board. The harness extends in the first direction. The first harness is electrically connected between the first toner cartridge connector and the drum-cartridge circuit board. The first harness extends in the second direction.

A drum cartridge that is mountable to and demountable from a main body of an image forming apparatus, the drum cartridge including: a photosensitive drum rotatable about a first axis extending in a first direction; and a first conveying roller rotatable about a second axis extending in the first direction, the first conveying roller being in contact with a second conveying roller of the image forming apparatus and being configured to convey a sheet, which is sandwiched between the first conveying roller and the second conveying roller, toward the photosensitive drum in a state where the drum cartridge is mounted on the main body, in which the drum cartridge has a guide groove into which an end portion of the second conveying roller in the first direction is inserted in the state where the drum cartridge is mounted on the main body.

A drum cartridge includes a first photosensitive drum, a frame, a main body connector, a first toner cartridge connector, a drum-cartridge circuit board, a harness, and a first harness. The harness is electrically connected between the main body connector and the drum-cartridge circuit board. The harness extends in the first direction. The first harness is electrically connected between the first toner cartridge connector and the drum-cartridge circuit board. The first harness extends in the second direction.

An image forming apparatus includes a latent-image forming unit that forms an electrostatic latent image onto an image carrier, a developing member that develops the electrostatic latent image held on the image carrier with a developer, a container that contains the developer supplied to the developing member, a stirring member that stirs the developer by rotating in the container, a density detecting unit that is disposed in the container and that detects a density of the developer, and a switching unit that switches an image formation condition by using a period of a signal output by the density detecting unit.