A charging member includes a support member, a conductive elastic layer disposed on the support member, and a front surface layer disposed on the conductive elastic layer. Irregularities with a cycle of shorter than 0.1 mm and irregularities with a cycle of 0.1 mm or longer are distributed on an entirety of an outer circumferential surface of the charging member, and satisfy the following conditions of (1) and (2): (1) the irregularities with the cycle of shorter than 0.1 mm have an average height of from 8 m to 11 m; and (2) the irregularities with the cycle of 0.1 mm or longer have an average height of from 2 m to 5 m. A half-value width of the maximum frequency value of height distribution on the outer circumferential surface is from 1 m to 3 m.

A charging member includes a support member, a conductive elastic layer disposed on the support member, and a front surface layer disposed on the conductive elastic layer. Irregularities with a cycle of shorter than 0.1 mm and irregularities with a cycle of 0.1 mm or longer are distributed on an entirety of an outer circumferential surface of the charging member, and satisfy the following conditions of (1) and (2): (1) the irregularities with the cycle of shorter than 0.1 mm have an average height of greater than 0 m and 4 m or less; and (2) the irregularities with the cycle of 0.1 mm or longer have an average height of from 5 m to 30 m. A half-value width of a maximum frequency value of height distribution on the outer circumferential surface is from 1 m to 3 m.

A charging member includes a support member, a conductive elastic layer disposed on the support member, and a front surface layer disposed on the conductive elastic layer. Irregularities with a cycle of shorter than 0.1 mm and irregularities with a cycle of 0.1 mm or longer are distributed on an entirety of an outer circumferential surface of the charging member, and satisfy the following conditions of (1) and (2): (1) the irregularities with the cycle of shorter than 0.1 mm have an average height of from 8 m to 11 m; and (2) the irregularities with the cycle of 0.1 mm or longer have an average height of from 2 m to 5 m. A half-value width of the maximum frequency value of height distribution on the outer circumferential surface is from 1 m to 3 m.

An image forming apparatus for electrifying a surface of a photoreceptor with the use of an electrification member includes: a first output unit configured to output a first AC voltage; a second output unit configured to output a second AC voltage having the same frequency as a frequency of the first AC voltage and having a phase different from a phase of the first AC voltage; a superimposition unit configured to superimpose, on a DC component, an AC component containing at least one of the first AC voltage and the second AC voltage; and an application unit configured to apply a voltage that has been subjected to superimposition by the superimposition unit to the electrification member, wherein the superimposition unit changes the AC component to be superimposed on the DC component at a predetermined timing.

A charging system includes a charging member that rotates while following a rotating image holding body and that charges the image holding body, a removing member that rotates while following the rotating charging member in a state of being arranged at a contact position in contact with the charging member and that removes an adhered deposit adhered to the charging member, a moving member that moves the removing member to a separation position separated from the charging member and the contact position, and at least one processor, in which the processor is configured to cause the removing member to remove the adhered deposit adhered to the charging member only for a removal time by controlling the moving member to move the removing member arranged at the separation position to the contact position at a time determined in advance.

An image forming apparatus that forms an image on a medium includes: an image carrying member; a charging unit disposed in proximity to the image carrying member; a power supply unit configured to sequentially apply a plurality of charging voltages to the charging unit when the medium is not fed through; a current detecting unit configured to detect an AC value flowing through the charging unit; a processing unit configured to perform first charging voltage determination control to derive a peak-to-peak voltage value to be used in a process; and a storage unit configured to pre-store a reference peak-to-peak voltage value for each wastage level of the image carrying member, wherein the processing unit: prohibits execution of the first charging voltage determination control and performs second charging voltage determination control; and obtains a reference peak-to-peak voltage value and derives a peak-to-peak voltage value to be used in the process.

A charging system includes a charging member that rotates while following a rotating image holding body and that charges the image holding body, a removing member that rotates while following the rotating charging member in a state of being arranged at a contact position in contact with the charging member and that removes an adhered deposit adhered to the charging member, a moving member that moves the removing member to a separation position separated from the charging member and the contact position, and at least one processor, in which the processor is configured to cause the removing member to remove the adhered deposit adhered to the charging member only for a removal time by controlling the moving member to move the removing member arranged at the separation position to the contact position at a time determined in advance.

In an image forming apparatus, rotation of an image bearing member is started and stopped in a contact state between the image bearing member and a developing member. During a post-rotation operation, a controller ends application of a charging voltage after changing the charging voltage stepwisely to first and second charging voltages. The controller ends application of a developing voltage after changing the developing voltage stepwisely at a developing position to first and second developing voltages in synchronism with the first and second charging voltages. A potential difference between each of surface potentials of first and second regions and an associated one of the first and second developing voltages is maintained within a predetermined range. The controller carries out control so that an absolute value of the surface potential of at least one of the first and second regions is made low by passing a current under application of a transfer voltage.

An image forming apparatus includes a drum, a first charger configured to charge at a first charging portion between the drum and the first charger in response to application of a first charging voltage, a developing roller configured to supply a developer to the drum at a developing portion, a second charger configured to form a second charging portion downstream of the first charging portion and upstream of the developing portion in drum rotation direction, and to charge by discharge at the second charging portion in response to application of a second charging voltage, and a controller configured to control voltage application, and the controller is configured to control such that the second charging voltage to start discharge is applied to the second charger during the rotation of the drum and after application of the first charging voltage.

A charging roller comprises a conductive shaft, an elastic body layer, and a surface layer. The surface layer contains a binder resin and conductive particles. The binder resin contains only a thermoplastic resin. The thermoplastic resin has a water contact angle of not less than 40 but less than 180. The conductive particles contain first conductive particles and second conductive particles. The first conductive particles are metal oxide particles. A content of the first conductive particles in the surface layer is not less than 15.0 parts by mass but not more than 200.0 parts by mass with respect to 100.0 parts by mass of the binder resin. A particle size distribution of the conductive particles has at least one peak within a range of not less than 0.01 m but not more than 1.00 m.