The intermediate transfer unit includes: an endless intermediate transfer belt which is turned around while carrying a toner image on its outer circumferential surface; and a plurality of rollers on which the intermediate transfer belt is turnably stretched, wherein the intermediate transfer belt has, on its inner circumferential surface, an information recording area in which belt information has been recorded, and the intermediate transfer belt has a mark at a position in the outer circumferential surface where a positional relationship between the mark and the information recording area comes to a specified relationship.

The intermediate transfer unit includes: an endless intermediate transfer belt which is turned around while carrying a toner image on its outer circumferential surface; and a plurality of rollers on which the intermediate transfer belt is turnably stretched, wherein the intermediate transfer belt has, on its inner circumferential surface, an information recording area in which belt information has been recorded, and the intermediate transfer belt has a mark at a position in the outer circumferential surface where a positional relationship between the mark and the information recording area comes to a specified relationship.

An image formation apparatus includes: a plurality of image formers each of which is provided for each color and forms a toner image; a plurality of image carriers each of which is provided in accordance with each of the image formers and carries the toner image formed by each image former; a first intermediate transfer body on which multiple toner images are formed; a secondary transferor that secondarily transfers to a sheet, the multiple toner images formed on the first intermediate transfer body; and an adhesion force reducer that is provided between a position where the multiple toner images are formed on the first intermediate transfer body and a secondary transfer position of the secondary transferor and that reduces an adhesion force of toner included in the multiple toner images formed on the first intermediate transfer body.

An image formation apparatus includes: a plurality of image formers each of which is provided for each color and forms a toner image; a plurality of image carriers each of which is provided in accordance with each of the image formers and carries the toner image formed by each image former; a first intermediate transfer body on which multiple toner images are formed; a secondary transferor that secondarily transfers to a sheet, the multiple toner images formed on the first intermediate transfer body; and an adhesion force reducer that is provided between a position where the multiple toner images are formed on the first intermediate transfer body and a secondary transfer position of the secondary transferor and that reduces an adhesion force of toner included in the multiple toner images formed on the first intermediate transfer body.

A transfer device includes a holding body, a transfer body, and a setting portion. The holding body holds multiple layers including a base layer formed of a toner having a mass larger than a threshold. The toner is electrically charged by a charging device. The transfer body transfers the layers on the holding body to a recording medium. The setting portion sets the charging device so that the charging device electrically charges a toner immediately after being transferred to the holding body with a larger amount of electric charges when the base layer is located uppermost on the holding body, than when the base layer is located other than uppermost on the holding body.

A layered structure includes a thyristor and a light-emitting element. The thyristor at least includes four layers. The four layers are an anode layer, a first gate layer, a second gate layer, and a cathode layer arranged in this order. The light-emitting element is disposed such that the light-emitting element and the thyristor are connected in series. The thyristor includes a semiconductor layer having a bandgap energy smaller than bandgap energies of the four layers.

Provided is an electrophotographic photosensitive member capable of achieving both high leak resistance and reduction in variations in dark part potential and bright part potential due to repeated use even when CB is used for an electrically conductive layer. An electrophotographic photosensitive member including: a support, an electrically conductive layer, and a photosensitive layer, sequentially, wherein the electrically conductive layer contains a binder resin and carbon black, a number average primary particle diameter of the carbon black is 200 nm or more and 500 nm or less, an average inter-particle distance of the carbon black is 200 nm or more and 600 nm or less, a coefficient of variation of an inter-particle distance is 1.2 or less, and SF-1 of the carbon black is 150 or less.

Provided is an electrophotographic photosensitive member capable of achieving both high leak resistance and reduction in variations in dark part potential and bright part potential due to repeated use even when CB is used for an electrically conductive layer. An electrophotographic photosensitive member including: a support, an electrically conductive layer, and a photosensitive layer, sequentially, wherein the electrically conductive layer contains a binder resin and carbon black, a number average primary particle diameter of the carbon black is 200 nm or more and 500 nm or less, an average inter-particle distance of the carbon black is 200 nm or more and 600 nm or less, a coefficient of variation of an inter-particle distance is 1.2 or less, and SF-1 of the carbon black is 150 or less.

In accordance with an embodiment, an image forming apparatus encompasses a heat roller, a lamp, a use amount acquisition section, a switching controller and a cycle controller. The heat roller heats a sheet printed with a toner image. The lamp heats the heat roller. The use amount acquisition section acquires a use amount of the lamp. The switching controller repeats a processing from a moment at which the lamp is charged until the lamp is charged next after the lamp is not charged in a predetermined control cycle. The cycle controller sets the cycle based on the use amount.

In accordance with an embodiment, an image forming apparatus encompasses a heat roller, a lamp, a use amount acquisition section, a switching controller and a cycle controller. The heat roller heats a sheet printed with a toner image. The lamp heats the heat roller. The use amount acquisition section acquires a use amount of the lamp. The switching controller repeats a processing from a moment at which the lamp is charged until the lamp is charged next after the lamp is not charged in a predetermined control cycle. The cycle controller sets the cycle based on the use amount.