An image forming apparatus includes: a photoconductor; an optical scanner configured to cause a plurality of light beams to scan simultaneously on a surface of the photoconductor; a pixel size calculator configured to calculate a pixel size corresponding to a scanning position of each of the light beams; a light-quantity value quantization converter configured to quantize a light-quantity value corresponding to the scanning position of each of the light beams; a storage configured to store conversion data for conversion from image density data into a light beam driving signal; a signal converter configured to perform, with the conversion data, conversion from the image density data into the light beam driving signal; a selector configured to select the conversion data, according to the pixel size calculator and the light-quantity value quantization converter; and a light source configured to emit the plurality of light beams, based on driving data obtained through conversion by a driving data converter with the conversion data selected by the selector, in which a number of pieces of the conversion data correspond to a number resulting from a number of obtainable pixel size values×a number of obtainable light-quantity quantized values×a number of light beams.

A power supply device that applies a voltage in which a direct-current (DC) voltage and an alternating-current (AC) voltage are superimposed on each other to a charging member that charges an image bearer, includes: an AC voltage generation circuit that generates the AC voltage; a DC voltage generation circuit that generates the DC voltage; a DC current detection circuit provided on an output terminal side of the DC voltage generation circuit, which detects an output DC current flowing into the image bearer; and a reduction circuit that reduces an inflow of an AC current to the DC current detection circuit.

An imaging system includes an image carrier, a charging device to form a toner image by charging a surface of the image carrier, a polishing roller, and a control device. A discharge product is generated on the surface of the image carrier as a result of charging the image carrier, and the polishing roller polishes the discharge product generated on the surface of the image carrier. The control device controls a polishing operation of the polishing roller in response to one or more detected characteristics.

An image forming apparatus includes: a photoconductor; an optical scanner configured to cause a plurality of light beams to scan simultaneously on a surface of the photoconductor; a pixel size calculator configured to calculate a pixel size corresponding to a scanning position of each of the light beams; a light-quantity value quantization converter configured to quantize a light-quantity value corresponding to the scanning position of each of the light beams; a storage configured to store conversion data for conversion from image density data into a light beam driving signal; a signal converter configured to perform, with the conversion data, conversion from the image density data into the light beam driving signal; a selector configured to select the conversion data, according to the pixel size calculator and the light-quantity value quantization converter; and a light source configured to emit the plurality of light beams, based on driving data obtained through conversion by a driving data converter with the conversion data selected by the selector, in which a number of pieces of the conversion data correspond to a number resulting from a number of obtainable pixel size values×a number of obtainable light-quantity quantized values×a number of light beams.

There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including: an electrophotographic photosensitive member and a charging member, in which when average local potential differences of calculated lengths in the electrophotographic photosensitive member is calculated based on a specific method, a maximum value of the average local potential difference is 2 V or more, the charging member includes a support and an electro-conductive layer, the electro-conductive layer has a matrix and domains dispersed in the matrix, a volume resistivity ρM of the matrix is at least 1.00×10.sup.5 times a volume resistivity ρD of the domain, and a specific calculated length S.sub.CP [μm] and a specific value relating a distance between the domains D.sub.ms [μm] satisfy S.sub.CP≥3×D.sub.ms.

An image forming apparatus that executes an image forming operation for forming a toner image on a recording material and an application operation of applying a metal soap to a surface of an image bearing member by supplying a toner stored in a toner storing unit to the surface of the image bearing member from the developing member. A surficial moving speed of the image bearing member during the application operation is lower than the surficial moving speed of the image bearing member during the image forming operation, and a speed difference between the surficial moving speed of the developing member and the surficial moving speed of the image bearing member during the application operation is larger than that during the image forming operation.

An imaging system includes an image carrier, a charging device to form a toner image by charging a surface of the image carrier, a polishing roller, and a control device. A discharge product is generated on the surface of the image carrier as a result of charging the image carrier, and the polishing roller polishes the discharge product generated on the surface of the image carrier. The control device controls a polishing operation of the polishing roller in response to one or more detected characteristics.

There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including: an electrophotographic photosensitive member and a charging member, in which when average local potential differences of calculated lengths in the electrophotographic photosensitive member is calculated based on a specific method, a maximum value of the average local potential difference is 2 V or more, the charging member includes a support and an electro-conductive layer, the electro-conductive layer has a matrix and domains dispersed in the matrix, a volume resistivity M of the matrix is at least 1.0010.sup.5 times a volume resistivity D of the domain, and a specific calculated length S.sub.CP [m] and a specific value relating a distance between the domains D.sub.ms [m] satisfy S.sub.CP3D.sub.ms.

An image forming apparatus that executes an image forming operation for forming a toner image on a recording material and an application operation of applying a metal soap to a surface of an image bearing member by supplying a toner stored in a toner storing unit to the surface of the image bearing member from the developing member. A surficial moving speed of the image bearing member during the application operation is lower than the surficial moving speed of the image bearing member during the image forming operation, and a speed difference between the surficial moving speed of the developing member and the surficial moving speed of the image bearing member during the application operation is larger than that during the image forming operation.

A setting determination apparatus includes: a measurer that measures a physical property of a medium; and a hardware processor. The hardware processor specifies a basis weight and a type of the medium based on a result of the measurement by the measurer and outputs the specified basis weight and type of the medium as a medium setting candidate for an operation setting for image forming.