Provided is an image formation device including a photoreceptor configured to carry a toner image and a developer configured to form the toner image on a surface of the photoreceptor and configured such that the developer is a replaceable development unit, the image formation device including: a development bias application section configured to apply a development bias to between the photoreceptor and the developer; a stabilization control section configured to perform image stabilization control of determining a development bias value to be used in future by changing the development bias while measuring a density of the toner image formed by the developer, thereby obtaining the toner image with a target density; and a life determination section configured to determine expiration of use of the development unit when the development bias value determined by the stabilization control falls outside a preset acceptable range.

An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A registration mark sensing system is positioned to detect the printed registration marks. The registration mark sensing system includes a light detector positioned to detect light that is emitted by a light source, transmitted through the transport web and reflected off a non-white colored reflector plate positioned behind the transport web. The colored reflector plate has a color that provides detection signals for the registration marks having a magnitude that is greater than or equal to a predefined threshold.

An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A first registration mark sensing system is positioned to detect the registration marks printed with a first subset of the toners that doesn't include the white toner. A second registration mark sensing system is positioned to detect the registration marks printed with a second subset of the toners that includes the white toner. The registration mark sensing systems each include a reflector plate positioned behind the transport web. The reflector plate for the first registration mark sensing system is white, and the reflector plate for the second registration mark sensing system is black.

An image forming apparatus has a normal image formation mode and a wide color gamut image formation mode in which an amount of a developer per unit area of a developer image of at least a color that differs from a prescribed color among a plurality of colors is increased as compared to the normal image formation mode. Image data is generated such that an image portion formed in the prescribed color in an image formed on a recording material is formed solely by a developer image of the prescribed color in the normal image formation mode, but formed by superimposing a developer image of a color that differs from the prescribed color on a developer image of the prescribed color or formed solely by a developer image of a different color in place of a developer image of the prescribed color in the wide color gamut image formation mode.

An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A registration mark sensing system is positioned to detect the printed registration marks. The registration mark sensing system includes a light detector positioned to detect light that is emitted by a light source, transmitted through the transport web and reflected off a non-white colored reflector plate positioned behind the transport web. The colored reflector plate has a color that provides detection signals for the registration marks having a magnitude that is greater than or equal to a predefined threshold.

An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A first registration mark sensing system is positioned to detect the registration marks printed with a first subset of the toners that doesn't include the white toner. A second registration mark sensing system is positioned to detect the registration marks printed with a second subset of the toners that includes the white toner. The registration mark sensing systems each include a reflector plate positioned behind the transport web. The reflector plate for the first registration mark sensing system is white, and the reflector plate for the second registration mark sensing system is black.

An image forming apparatus has a normal image formation mode and a wide color gamut image formation mode in which an amount of a developer per unit area of a developer image of at least a color that differs from a prescribed color among a plurality of colors is increased as compared to the normal image formation mode. Image data is generated such that an image portion formed in the prescribed color in an image formed on a recording material is formed solely by a developer image of the prescribed color in the normal image formation mode, but formed by superimposing a developer image of a color that differs from the prescribed color on a developer image of the prescribed color or formed solely by a developer image of a different color in place of a developer image of the prescribed color in the wide color gamut image formation mode.

An image forming apparatus has a normal image formation mode and a wide color gamut image formation mode in which an amount of a developer per unit area of a developer image of at least a color that differs from a prescribed color among a plurality of colors is increased as compared to the normal image formation mode. Image data is generated such that an image portion formed in the prescribed color in an image formed on a recording material is formed solely by a developer image of the prescribed color in the normal image formation mode, but formed by superimposing a developer image of a color that differs from the prescribed color on a developer image of the prescribed color or formed solely by a developer image of a different color in place of a developer image of the prescribed color in the wide color gamut image formation mode.

An image forming apparatus includes a frame, a drum cartridge mountable to the frame, and including a photosensitive drum and a drum memory in which drum identification information identifying the drum cartridge is stored, and a control unit including a main body memory in which the drum identification information is to be stored. The control unit reads out the drum identification information from the drum memory, determines whether the drum identification information read out from the drum memory coincides with the drum identification information stored in the main body memory, and enables to execute resister pitch measuring processing of measuring variations in printing pitch due to the photosensitive drum. In a case where it is determined that the drum identification information read out from drum memory coincides with the drum identification information stored in the main body memory, the control unit does not execute the resister pitch measuring processing.

An image forming apparatus has a normal image formation mode and a wide color gamut image formation mode in which an amount of a developer per unit area of a developer image of at least a color that differs from a prescribed color among a plurality of colors is increased as compared to the normal image formation mode. Image data is generated such that an image portion formed in the prescribed color in an image formed on a recording material is formed solely by a developer image of the prescribed color in the normal image formation mode, but formed by superimposing a developer image of a color that differs from the prescribed color on a developer image of the prescribed color or formed solely by a developer image of a different color in place of a developer image of the prescribed color in the wide color gamut image formation mode.