An image forming apparatus includes an image forming section, a sensor and a control section. The image forming section forms a first image with at least two kinds of developing agents with different fixation properties. The sensor detects the first image formed on an image formed section by the image forming section. The control section amends deviation of the first image on the image formed section by the image forming section when a detection result of the sensor that the first image formed by the image forming section is not formed at a predetermined position of the image formed section.

An image forming apparatus includes an intermediate transfer belt, a density sensor, a cleaning device and a density correction unit. The intermediate transfer belt carries a calibration toner image. The density sensor detects a density of the calibration toner image that passes at a predetermined position. The cleaning device contacts to a part of the intermediate transfer belt in a primary scanning direction, and removes from the intermediate transfer belt the calibration toner image that passed at the predetermined position. The density correction unit performs density correction of a printing toner image in the primary scanning direction. Further, the density correction unit changes a strength of the density correction for a contact range to which the cleaning device contacts on the intermediate transfer belt, the strength changed in accordance with the number of times of a calibration process.

An image forming apparatus including: a developing roller configured to develop an electrostatic latent image on a photosensitive drum to form a toner image; a belt onto toner image is transferred; a detection unit configured to detect a density of an image for detection formed on the belt; and a controller configured to perform hue adjustment based on a detection result of the detection unit, wherein the image forming apparatus performs image formation in a second mode using a color gamut different from a color gamut in a first mode, and the controller obtains a lookup table, which indicates a correlation between image data to be used and input image data in the second mode, based on the detection result in the first mode and a correlation of density between the first mode and the second mode.

A sensor includes a light emitter and a photodetector. The light emitter outputs light with which a toner pattern or a surface material of an image carrier is irradiated. The photodetector receives reflection light from the toner pattern or the surface material. The sensor light intensity control unit provides a control voltage to the light emitter and thereby controls light intensity of the light emitter. The density determining unit determines a toner density on the basis of output of the photodetector. Further, the density determining unit (a) determines as a correction parameter a first-order coefficient of the control voltage of the light emitter for an output voltage of the photodetector corresponding to reflection light from the surface material, (b) determines a correction amount corresponding to the correction parameter and the toner density, and (c) corrects the toner density on the basis of the correction amount.

An image forming apparatus is capable of switching thresholds for deciding a color registration amount from a pattern image. A controller controls image forming units to form first and second color patterns of different colors on a rotational image bearing member. The second color pattern is formed at an upstream side of the first color pattern in a rotational direction of the image bearing member. The controller controls a sensor to detect the color patterns. A comparator compares a detection result by the sensor with a threshold, and outputs an output value according to a comparison result. The controller controls the color registration according to the output value. The controller sets a second threshold for the second color pattern based on an edge timing of the output value from the comparator according to the comparison result between the detection result about the first color pattern and a first threshold.

In an image forming apparatus, a plurality of light emitting portions arrayed in an array direction. A lens array has a length in the array direction longer than a length in a direction orthogonal to the array direction. A controller is configured to perform: converting a reference printing pattern including a plurality of first linear patterns to a detection pattern including a plurality of second linear patterns, each of the plurality of first linear patterns forming a first angle with respect to a reference line parallel to the array direction, each of the plurality of second linear patterns forming a second angle smaller than the first angle with respect to the reference line; forming a detection pattern image on a transfer medium; detecting a print density of the detection pattern image with a sensor; and setting an image formation condition according to the print density detected by the sensor.

A method of adjusting an imaging apparatus comprises printing a set of test patches, the set of test patches comprising a solid color patch, a grey level patch and a substrate patch. The optical densities of the set of test patches are determined. The method comprises simultaneously correcting a solid optical density value (Solid OD), relating to the solid color patch and an associated grey level (LUT) value relating to the grey level patch.

Provided is an image forming apparatus wherein a transfer material transport guide 35 is disposed in an optical sensor unit 29 to support a color deviation sensor, which is disposed near an intermediate transfer belt 6. By changing the position of the optical sensor unit 29, the grounding path of the transfer material transport guide 35 can be changed, and both the transfer bias leak prevention for the transfer material transport guide 35 and the electrostatic breakdown prevention for the color deviation sensor can be implemented. As a result, the apparatus can be downsized, and only when the intermediate transfer belt is replaced, the optical sensor unit 29 can be moved to create a space necessary for the replacement.

An image forming apparatus includes a CPU configured to change a parameter value used to control a developer bearing amount and form a plurality of patches for different parameter values changed, and a color sensor configured to measure the plurality of patches thereby acquiring color information thereof. The CPU detects, from values of color information of the plurality of patches, a value of the color information at which a change greater than or equal to a predetermined threshold value occurs, and the CPU sets a parameter used in forming an image based on the detected value of color information.

An image forming apparatus includes an image carrying member, a developing device, a cleaning unit and a processor. The developing device performs development with a developer containing a toner and a lubricant. The processor obtains information on a lubricant amount in the developing device; obtains, with respect to each section formed by dividing a surface of the image carrying member in a rotating shaft direction of the image carrying member, a partial coverage from electrostatic latent image writing information for a predetermined period about the section; sets, for the section having the partial coverage of a predetermined value or less, a developer supply amount for a patch to be formed outside an image forming region on the image carrying member, based on the above information; and causes the developing device to supply the set developer supply amount so that the patch is formed.