A housing includes a first opening and a second opening, and encloses a light-emitting element, a first light receiving unit, and a second light receiving unit. The first opening is provided in a first light guide path arranged between the light-emitting element and a first irradiated region of the target surface, and is arranged so that light output from the light-emitting element travels toward the first irradiated region. The second opening is provided in a second light guide path arranged between the first irradiated region and the first light receiving unit, and is arranged so that diffused reflection light from the toner image passes through when the toner image passes the first irradiated region.

An image forming apparatus includes: an image forming unit configured to form an image on an intermediate transfer member; a transfer member configured to output a transfer voltage, in order to cause a transfer current to flow so as to transfer the image to a sheet; a first measurement unit configured to measure a density of the image; and a control unit configured to: control the image forming unit to form a test image on the intermediate transfer member based on test image data; control the first measurement unit to acquire a measured density of the test image; correct the measured density based on an evaluation value of an electric resistance of a path through which the transfer current flows; and generate data for density correction, based on the test image data and a corrected measured density.

A processor causes a printing portion to execute, when first conveying processing is executed, test print processing for executing processing of forming a plurality of test toner images on a sheet under a print condition that differs for each of the plurality of test toner images. The processor acquires a plurality of first sensing densities when the first conveying processing is executed. The processor causes the printing portion to execute the test print processing when second conveying processing is executed. The processor acquires a plurality of second sensing densities when the second conveying processing is executed. The processor compares the plurality of first sensing densities and the plurality of second sensing densities to adjust the print condition in the print processing when the second conveying processing is executed.

An intermediate transfer belt that can bear a toner image includes a first layer and a second layer. The first layer includes a first surface located on an outer peripheral surface side of the first layer. The second layer is provided on a side of the first surface, transmits light, and includes a second surface. The first surface includes first grooves that (i) extend in a first direction in a circumferential direction of the intermediate transfer belt and (ii) are arranged in a width direction of the intermediate transfer belt that is orthogonal to the circumferential direction. The second surface is located on an outer peripheral surface side of the second layer, contacts a toner image, and includes second grooves that extend in a second direction in the circumferential direction. The first grooves includes 80 or more grooves per 1-mm length in the width direction in the first surface.

An image forming apparatus is configured to control a generation circuit to modulate a DC component of a developing voltage based on a first correction component such that a density unevenness is reduced. The image forming apparatus is further configured to restrict the first correction component for modulating the DC component of the developing voltage such that fogging of toner that may occur on a non-exposure region which is not exposed by an exposure unit and adhesion to a photosensitive member of carrier included in a developer are reduced.

A color image processing apparatus includes an image forming unit configured to form a color image using recording materials of plural colors, an image processing unit configured to implement plural image processing methods that achieve plural types of pseudo-halftone representations, a color measurement unit configured to perform color measurement of the color image formed by the image forming unit, and a control unit configured to control execution of multi-color calibration in which the color measurement unit performs color measurement of a pattern image including plural multi-color patch images formed using recording materials of plural colors by using a smaller number of image processing methods than plural image processing methods used in single-color calibration for correcting reproduction characteristics of single-color images formed by the image forming unit and in which reproduction characteristics of a multi-color image formed by the image forming unit are corrected using a result of the color measurement.

An image forming apparatus includes an image carrier, an image forming unit, a transfer unit, a detector, a controller, an edge detector, and an abnormality detector. The detector detects developer attached to an image carrying surface at a position between a position where an image is formed and a position where the image is transferred. The controller controls the image forming unit such that a check image including an edge that extends in a direction intersecting the moving direction of the image carrying surface is formed in a region of the image carrying surface that passes through the detection position. The edge detector determines a position of the edge based on a detection status of the developer. The abnormality detector determines whether or not the image former is abnormal based on the position of the edge.

In an image forming apparatus, a controller (a) determines a bright potential of a photoconductor drum at calibration, (b) adjusts a development bias and thereby determines as an intermediate reference development bias value a value of the development bias so that a toner density based on an output of a reflection-type optical sensor is equal to an intermediate reference density lower than a target density, (c) determines as an intermediate reference effective potential a difference between the intermediate reference development bias value and the bright potential at calibration, and (d) determines a development bias value corresponding to the target density by linear interpolation based on the intermediate reference effective potential and a virtual zero density effective potential. The virtual zero density effective potential is a difference between a development bias and a bright potential of the photoconductor drum when a transmission density is virtually zero.

Disclosed herein is an image forming apparatus. The image forming apparatus includes a sensing unit having a window and a sensor which senses a developer through the window, and a shutter device which opens and closes the window, and thereby the sensing unit in a sensible state is maintained, and a lifetime thereof is extendable.

An image forming apparatus capable of controlling density of an output image with high accuracy regardless of variation of internal temperature. A controller controls an image forming unit to form a measurement image, controls a light receiving unit to receive reflected light from the measurement image, controls a conversion unit to convert an output value of the light receiving unit, and controls an image formation condition based on a value that is obtained by converting the output value. An adjustment unit controls the light receiving unit to receive reflected light from an image bearing member, and adjusts the emission light amount of an emission unit based on the reflected light from the image bearing member. A selection unit selects a conversion condition from among conversion conditions based on a reference temperature that is detected when the adjustment unit adjusts the emission light amount and a current temperature.