A developing device for forming an image by developing an electrostatic latent image formed on an image carrier with a developer, includes: a developing container that accommodates the developer, a developing roller that faces the image carrier, is disposed adjacent to the developing container, and conveys the developer accommodated in the developing container to the image carrier, and a developer discharging part that is provided in the developing container and discharges a part of the developer, wherein a discharge amount of the developer discharged by the developer discharging part is controlled on the basis of a charge amount of a toner included in the developer.

An electrophotographic imaging device having a method of printing which includes determining whether a duty cycle state in the imaging device has changed; selecting one of a full toner density calibration and a partial toner density calibration based on the determining; performing the one of the full toner density calibration and the partial toner density calibration; identifying a toner density to be applied during printing as a result of the performing; developing a toned image having a toner density equal to the toner density identified; and printing the toned image on a media sheet, wherein the full toner density calibration is skipped upon at least a determination that the duty cycle state has remained the same.

A developing device includes: an image bearing member; a plurality of developing rollers each supplying toner to the image bearing member, and developing an electrostatic latent image on the image bearing member into a toner image; and a hardware processor analyzing values representing density fluctuations during the toner being supplied from the developing rollers to the image bearing member, for the respective developing rollers, and correcting a control value for an image density of at least one developing roller among the developing rollers based on an result of the analyzing so as to eliminate the density fluctuations, in consideration of an effect caused at the developing roller on a downstream side in a rotational direction of the image bearing member by correcting the control value for the image density of the developing roller on an upstream side.

An image forming apparatus includes a printer and a controller. The printer transfers an image formed by attaching toner to an electrostatic latent image onto a sheet, heats and presses the sheet onto which the visible image is transferred to fix the image onto the sheet, and thereby forms an image on the sheet. The controller controls the printer to form an image for a second surface, and then to form an image for a first surface which differs from a surface on which the image for the second surface is formed, when the controller determines that duplex printing, in which decolorable toner is used on the first surface on which an image is first formed, and toner having a fixing temperature higher than a decolorizing temperature is used on the second surface, is set in printing job data.

An image forming apparatus determines a toner density erroneous detection state based on a patch image density in patch detection auto toner replenishing and, when the toner density erroneous detection state is determined, offsets a target toner density by the amount of erroneous detection so that the actual toner density becomes a desired toner density.

An electrophotographic imaging device having a method of printing which includes setting a default toner density for printing; developing a first toned image having the default toner density; printing the first toned image on a first page of a print job; and before printing a second page of a print job, determining whether a duty cycle state of a photoconductive member in the imaging device has changed, and upon a positive determination, developing a second toned image having a toner density derived from the default toner density and printing the second toned image on the second page.

A toner coverage sensing system is provided for sensing toner particles printed onto a surface of a process element using an electrophotographic printing system. The printed toner particles include porous color toner particles. An infrared radiation source directs infrared radiation onto the printed toner particles on the surface of the process element A diffused radiation detector senses infrared radiation scattered from the printed toner particles, wherein the diffused radiation detector is oriented such that that the sensed infrared radiation does not include specular reflections from the surface of the process element. A data processing system determines a sensed toner coverage for the porous color toner particles on the surface of the process element responsive to the sensed scattered infrared radiation.

An apparatus converts image data based on a conversion condition, forms an image using a developer, measures the developer, and a humidity. The apparatus determines a first density of an image when a mode of the apparatus changes from a power saving mode in which the apparatus cannot form an image to a normal mode in which the apparatus can form an image, from values measured, based on a first determination condition, determines a second density of an image when the apparatus has formed images on a predetermined number of sheets in the normal mode, from values measured, based on a second determination condition that is different from the first determination condition, and generates the conversion condition based on the first density and the second density.

First correction data for use in a first printing mode is generated by image density measurement in the first printing mode, and second correction data for use in a second printing mode, which is different from the first printing mode in peripheral speed ratio of a developing roller to a photosensitive drum, is generated by image density measurement in the second printing mode. First processing for generating first and second correction data for the first and second printing modes, respectively, by density measurement, or second processing for generating the first correction data by density measurement and generating the second correction data using the generated first correction data and a difference in image density between the first printing mode and the second printing mode is executed. The first processing is executed when a predetermined condition is satisfied.

An image forming apparatus includes: an image forming unit comprising: a photosensitive member configured to rotate; a charging unit configured to charge the photosensitive member based on a charging bias; an exposure unit configured to expose the photosensitive member charged by the charging unit with laser light to form an electrostatic latent image on the photosensitive member; and a developing device configured to develop the electrostatic latent image based on a development bias to form an image on the photosensitive member, a reading unit configured to read a test image formed by the image forming unit, and a controller configured to: control the image forming unit to form the test image; control the reading unit to read the test image.