An image forming apparatus includes: a capacitance detector that detects capacitance of an opposing member disposed opposite to a photoconductor, wherein the capacitance detector detects the capacitance of the opposing member, based on a result of measurement of a current flowing due to potential difference between a voltage applied to the opposing member and the photoconductor being charged.

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.

An image forming method includes: developing an electrostatic latent image with a toner to form a toner image; and transferring the toner image onto a recording medium and irradiating the toner image with an actinic ray to fix the toner image to the recording medium, wherein in the transferring, a plurality of types of toner particles containing toner particles of a color toner and toner particles of a transparent toner is fixed to the same area included in the recording medium.

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 photosensitive member, a charging roller, an image forming portion. The charging roller includes an electroconductive rubber layer and is 20 m or more and 35 m or less in ten point average roughness of a surface thereof and 130 m or more and 250 m or less in average interval of surface unevenness.

A printing apparatus is provided. The apparatus comprises a light-emitting element, a light-receiving element including a first terminal and a second terminal, a reference current generator supplying a reference current, a comparator comparing a monitor current with the reference current, the light-receiving element supplying the monitor current to the second terminal in accordance with a light emission amount, a driver driving the light-emitting element based on an output of the comparator, and a reference voltage controller. The comparator includes a first input terminal connected to the second terminal and a second input terminal. The reference voltage controller supplies a reference voltage selected from at least two voltage values to the second input terminal, and to control the voltage of the second terminal to be a voltage according to the reference voltage.

A charging roller is configured to charge a surface of an image bearing member configured to bear an image. The charging roller includes: a shaft portion; an elastic layer formed around the shaft portion; and a surface layer formed around the elastic layer, wherein particles having particle diameters within a range of 2 m or larger and 15 m or smaller and dispersed in the surface layer, and wherein a reduced peak height Spk (m), a reduced dale height Svk (m), and a core height Sk (m) with respected to the surface layer of the charging roller satisfy 4Spk+Sk8 and 0.5Svk1.

A mode control section forms a plurality of reference toner images having different densities on a photosensitive drum, where the frequency of an alternating-current voltage of a development bias is varied with a potential difference between direct-current voltages of a development roller and the photosensitive drum maintained constant, generates a reference straight line indicating a relationship between a toner amount of each reference toner image obtained by converting the density of the measured reference toner image into weight, and a representative value of current values of a development current measured during formation of the reference toner image, and acquires the amount of electrostatic charge of toner using the reference straight line.

A mode control section forms a plurality of reference toner images having different densities on a photosensitive drum, where the frequency of an alternating-current voltage of a development bias is varied with a potential difference between direct-current voltages of a development roller and the photosensitive drum maintained constant, generates a reference straight line indicating a relationship between a toner amount of each reference toner image obtained by converting the density of the measured reference toner image into weight, and a representative value of current values of a development current measured during formation of the reference toner image, and acquires the amount of electrostatic charge of toner using the reference straight line.

A system and method for cooling electrostatic process units includes an impeller in communication with a shaft associated with a rotating component of the electrostatic process unit such as a toner mixer, a waste auger, a developer, or a photoconductive drum. When the shaft rotates, the impeller rotates and causes air to be directed into a cooling duct. The cooling duct directs the air over one or more components of the electrostatic process unit such as the developer or a doctor blade. The air directed over the components cools the electrostatic process unit.