Abstract: An image forming apparatus includes: a first image bearing member (drum); a second image bearing member (drum); a developing device for forming a toner image on the basis of an electrostatic latent image formed on the first drum; an electrostatic latent image forming portion for forming an electrostatic latent image mark on the first drum; a detecting portion for detecting a position of the electrostatic latent image mark; and an adjusting portion for adjusting, on the basis of a detection result of the position of the electrostatic latent image mark, superposition between the toner image formed on the first drum and the toner image formed on the second drum. An electrostatic latent image which is undetectable by the detecting means is formed between a formation region of the toner image on the first drum and a formation region of the electrostatic latent image mark on the first drum.

Abstract: An image processing apparatus is provided in which the accuracy of measurement of an amount of toner adhesion is improved by forming a toner image pattern according to a detection scheme for the amount of toner adhesion. In the image processing apparatus, a toner image pattern control unit 215 determines a detection scheme for the amount of toner adhesion of a toner image based on attribute information of the toner image, decides a toner image pattern according to the results of that determination, and forms that decided toner image pattern. A toner adhesion amount calculation unit 605 measures the amount of toner adhesion for the toner image pattern formed by the toner image pattern control unit 215.

Abstract: An image forming apparatus includes a conveyance unit to convey an image carrier and an image forming unit to form an image on the image carrier. The image forming apparatus also includes a first determining unit, a control unit, an irradiation unit, an output unit, and a second determining unit. The first determining unit determines a first image forming condition of the image forming unit for forming a heavy line image at a particular width and thickness. The control unit causes the image forming unit to form a first measurement image having a particular width and length. The irradiation unit emits light onto the image carrier. The output unit outputs a first signal corresponding to a thickness of the first measurement image by receiving reflected light. The second determining unit determines a second image forming condition for forming a fine line image at a particular width and thickness.

Abstract: A pattern detection sensor receives light diffused by a pattern image, and it is difficult for the pattern detection sensor to detect a low-reflectance black pattern. Considering this, a high-reflectance yellow pattern is formed as the background of the low-reflectance black pattern. Even the diffused light reception type pattern detection sensor can detect the black pattern. The yellow pattern formed as the background is also used as a yellow pattern for detecting a color misalignment amount with respect to a pattern of magenta working as a reference color. The consumption amount of yellow toner is reduced while maintaining the color misalignment correction precision.

Abstract: There is provided an image formation device, comprising: an image forming unit configured to execute image formation to form an image on a recording medium; a holding body configured to move relatively with respect to the image forming unit and to hold an image formed thereon by the image forming unit; a controller that controls the image forming unit to form a correction pattern in an area on the holding body, the area corresponding to an image formation area defined on the recording medium when the image formation is executed for the recording medium; a measurement unit configured to measure a position of the correction pattern formed on the holding body; and a correction unit configured to correct an image formation position of the image formation unit based on a measurement result of the measurement unit.

Abstract: An image-forming apparatus includes: a forming unit that forms an image on an image holder that is a rotating body holding an image; a measuring unit that measures a rotation amount of the image holder with reference to a certain position on the image holder; a determining unit that: identifies a position on the image holder from which an image is to be formed by the forming unit, according to the rotation amount measured by the measuring unit; if, while a plurality of images are successively formed on the image holder, an image for density correction is to be formed, postpones forming of the image for density correction until a timing arrives at which one image of the plurality of images is to be formed from a predetermined position on the image holder, and when the timing arrives at which the one image of the plurality of images is to be formed from the predetermined position on the image holder, determines to start forming of the image for density correction from the predetermined position, instead of form

Abstract: An image forming apparatus with a correction function for correcting density of an image, including: an image bearing member configured to convey the image in a first direction; and a controller configured to perform a bias correction and a ? correction for the density, wherein the controller includes: a test patch generator configured to generate on the image bearing member a test patch including a first test patch and a second test patch; a first density sensor configured to detect density of the first test patch; a second density sensor configured to detect density of the second test patch; a selector configured to select one of a first detection signal from the first density sensor and a second detection signal from the second density sensor as a bias-correction detection signal and another detection signal as a ?-correction detection signal.

Abstract: An image forming apparatus includes a direct transfer control unit that controls a direct transfer unit and a first image forming unit so as to directly transfer an image onto a transfer sheet, an indirect transfer control unit that controls an intermediate transfer unit and a second image forming unit so as to transfer images onto the intermediate transfer unit, a secondary transfer control unit that controls contact/separation between the direct transfer unit and the intermediate transfer unit, a first alignment control unit that corrects an amount of misalignment among the images formed on the intermediate transfer unit, thereby performing a first alignment control process, and a second alignment control unit that corrects an amount of misalignment of an image directly transferred onto the transfer sheet with respect to the image on which the first alignment control process has been performed, thereby performing a second alignment control process.

Abstract: According to one embodiment, a color image forming apparatus includes a pattern forming unit configured to form, if a first pattern for color drift detection may not be able be detected by a detecting unit, a second pattern having a size larger than the size of the first pattern on a transfer belt. The color image forming apparatus further includes a control unit configured to calculate, using a result of detection of the second pattern by the detecting unit, a shift between a detectable position of the detecting unit and a formation position of the first pattern and reform the first pattern.

Abstract: Electrophotographic (EP) streaking compensation is performed. A tonescale is measured for each column and a per-column gain computed to compensate for variations. An adjustment tonescale is determined and a per-column adjustment-tonescale gain computed to correct for remaining error after the per-column gain is applied. The two corrections are used together to provide improved compensation quality.

Abstract: In an image forming apparatus, a density adjustment unit causes to form a cleaner toner image on a surface of an image carrier and remove the cleaner toner image for density adjustment, and causes to form a test pattern after removing the cleaner toner image. The cleaner toner image is formed to cover a whole area on which the test pattern may be formed.

Abstract: An apparatus (100) and method (200) that evaluates printing apparatus cleaner performance. The method can be performed in a printing apparatus that can include an intermediate transfer belt (150), an intermediate transfer belt sensor (155), a developer (115), a photoreceptor (110), and a photoreceptor cleaner (120). The method can include placing (220) marking material on the photoreceptor using the developer. The method can include cleaning (230) the marking material on the photoreceptor using the photoreceptor cleaner. The method can include transferring (240) the marking material to the intermediate transfer belt. The method can include sensing (250) marking material on the intermediate transfer belt using the intermediate transfer belt sensor.

Abstract: An image forming apparatus includes an image bearing member to bear a toner image, a transfer device to transfer the toner image onto a recording medium, and a moving device controller to control a moving device that moves the transfer device such that the moving device moves the transfer device to contact the image bearing member during transfer of the toner image on the image bearing member to the recording medium; separates the transfer device from the image bearing member as a toner patch on the image bearing member passes through the transfer area; and maintains the transfer device in contact with the image bearing member from a preceding transfer of a toner image to a succeeding transfer of a toner image during continuous printing, as at least one of areas between successive toner images on the image bearing member without the toner patch passes through the transfer area.

Abstract: An image forming apparatus which includes a photosensitive member and an image forming station. The image forming station includes a charging device for charging the member, an exposure device for exposing the member to light, a developing device for developing an electrostatic latent image on the member, and a bias applying device for applying a developing bias. The image forming apparatus also includes, a transfer device for transferring a toner image to a sheet, a setting device for setting an AC voltage, an executing device for executing a test mode, a density detecting device for detecting the density of the test image, and an adjusting device for adjusting an image forming condition for the station. When the executing device executes the test mode, test images can formed at various AC voltages.

Abstract: An image forming apparatus including: a black image forming section for forming a black image and a first black pattern for a coarse correction of black and optionally a second black pattern for a precise correction of black; a color image forming section for forming a color image optionally a third pattern for a coarse correction of color and optionally a fourth pattern for a precise correction of color; and a control section for allowing at least the first black pattern to be formed and optionally a second black pattern and third and fourth color patterns, and controlling to perform the coarse correction of black for correcting a forming condition of a black image to be formed and to perform optionally a precise correction of black, the coarse and precise correction of color based on the measurement of the formed pattern(s), wherein the control section controls to perform the coarse correction of black but not to perform the precise correction of black and the coarse and precise corrections of color in case

Abstract: A sensor used for determining area coverages of each colorant in a printed image is provided. The sensor includes a plurality of sensing elements for determining area coverages of each colorant in a printed image that includes a plurality of colorants including a black colorant. One of the sensing elements is an infrared sensing element configured to measure infrared reflection, and the others of the sensing elements are each configured to detect a visible color.

Abstract: A light-emitting unit includes M (M?3) number of light-emitting elements. A light-receiving unit includes N (N?3) number of light-receiving elements that receive a reflected light from at least one of a supporting member and a toner pattern. The toner pattern is formed on a surface of the supporting member. A detection light is emitted onto the supporting member from the light-emitting unit. A reflected light reflected from at least one of the supporting member and the toner pattern is received by the light-receiving unit. A position of the toner pattern on the supporting member is detected based on outputs of the light-receiving elements.

Abstract: In an image forming apparatus, a first controller forms a first image pattern on an image bearer and determines a first image formation condition based on a detection result of density of a toner image. The first controller then controls a toner image forming device based on the first image formation condition. A second controller forms a second image pattern different from the first image pattern on an image bearer and determines a second image formation condition based on a detection result of density of a toner image. The second controller then controls a toner image forming device based on the second image formation condition.

Abstract: An image forming device to perform an auto color registration. The image forming device includes a print unit capable of performing a print job in accordance with a plurality of print modes, a color registration processing unit to perform an auto color registration (ACR), a storage unit to store color registration conditions for the respective print modes, and a control unit to control the color registration processing unit to perform the ACR in accordance with the color registration condition corresponding to the present print mode of the print unit. The color registration condition may be at least one of a color registration execution period, a color registration execution time, and a color registration pattern. According to the image forming device, the proper ACR can be performed by print modes.

Abstract: An image forming apparatus forms a plurality of tone patterns of different colors, each of which containing a plurality of toner patches having different toner densities. Some of the toner patches in each of the tone patterns are formed with a predetermined fixed developing bias and the rest of the toner patches in each of the tone patterns are formed with developing biases set based on previous developing biases that have been obtained through a previous control process. The largest toner density of the toner patches in each of the tone patterns is determined based on a magnitude relation of previous index values obtained through the previous control process.

Abstract: An image forming apparatus includes an image forming unit, a decision unit, an output unit, a control unit, and a setting unit. The image forming unit forms an image on an image bearing member. The decision unit decides a first image forming condition of the image forming unit for forming the image at a width that is wider than a predetermined width. The output unit outputs a signal in accordance with the thickness of the image. The control unit causes the image forming unit to form a measurement image having a width that is narrower than or equal to the predetermined width. The setting unit sets a second image forming condition of the image forming unit so that the thickness of the image that is narrower than or equal to the predetermined width becomes thinner than or equal to the predetermined thickness.

Abstract: An image forming apparatus includes: a conveyance member; a detection unit which outputs a detection signal according to a mark for image formation condition correction; an image forming unit which forms a print image and the mark; and a change unit which changes at least one of a printing reference position and a mark reference position such that an offset amount between the printing reference position and the mark reference position becomes larger as an angle difference between a sub-scanning direction and a conveyance direction of the conveyance member is larger, wherein the printing reference position is a basis of determining a formation position of the print image in a main scanning direction and the mark reference position is a basis of determining at least one of a formation position and a size of the mark in the main scanning direction.

Abstract: Systems and methods for implementing use of customer documents in maintaining image quality or image quality consistency of printing devices are provided. The system may include a marking engine constructed to print images on an image bearing surface of the print device; one or more color measuring devices for measured toner images formed on the image bearing surface corresponding to the one or more relevant pages, and an image analyzer configured to generate reference images and to compare measured image data with the reference images. The image analyzer may also be configured to analyze input image data for a document and to identify one or more relevant pages of the document that may provide information regarding the state of the printing system to generated reference image data. Comparisons between the color separations of the reference image data and measured image data images may be realized for determining defects.

Abstract: A color laser printer includes a belt conveying device having a conveyor belt for conveying a recording medium, an image forming unit that forms an image on the recording medium and a test pattern in a test-pattern area on a conveying surface of the conveyor belt, and a pressing member having a pressing surface that grows wider toward a downstream side with respect to a conveying direction in which the recording medium is conveyed and that presses the recording medium toward the conveying surface of the conveyor belt. The pressing member is disposed so that a prescribed gap is formed between the pressing surface of the pressing member and the test-pattern area on the conveying surface of the conveyor belt.

Abstract: An image forming apparatus includes an image carrier, an image forming member, a transferer, a toner image detector, and a controller. The transferer transfers the toner image from the image carrier directly or indirectly onto a recording medium transported by a surface moving member. The toner image detector detects a test toner image formed in a test toner image detection area located at an end portion of the surface moving member. The controller checks a length of the recording medium in a main scanning direction during continuous image formation, and forms the test toner image either in a space between recording media when the length of the recording medium exceeds a length of the surface moving member minus a length of the test toner image detection area in the main scanning direction or otherwise in parallel to the toner image transferred onto the recording medium.

Abstract: An image forming apparatus includes; an image forming unit; an annular belt that moves circularly; a detection unit that detects a state of a surface of the belt; and a tension increase unit that increases a tension of the belt, at a detection position by the detection unit, when detection is performed by the detection unit, as compared with the tension of the belt before detection at the detection position is performed by the detection unit.

Abstract: An image forming apparatus including an image carrier, a plurality of forming devices, a detecting device configured to perform a steady-deviation detection for detecting steady positional deviation and a varying-deviation detection for detecting varying positional deviation having a cycle, and a correcting device configured to perform a steady-deviation correction for correcting the steady positional deviation and a varying-deviation correction for correcting the varying positional deviation. The detecting device forms, during the steady-deviation detection, a steady-deviation detection pattern in a state where the varying deviation correction is selectively disabled. The steady-deviation detection pattern has a plurality of measuring points arranged in a longitudinal direction. The detecting device, during the steady-deviation detection, measures positional deviation amount at each measuring point, and detects the steady positional deviation based on the measurement result.

Abstract: An image forming apparatus includes: print data generating unit for generating gradation correction test chart print data to juxtapose and draw a basis density pattern having a basis density of a yellow color and plural reference density patterns having respective densities of the yellow color compared with the basis density and additionally draw a contrast effect pattern composed of colors having a contrast effect on the yellow color; printing unit for printing a gradation correction test chart including a yellow color gradation correction pattern in which the basis density pattern and the plurality of reference density patterns are juxtaposed and printed and the contrast effect pattern is additionally printed; receiving unit for receiving an input of a density adjustment value of any pattern based on a shading comparison of the basis density pattern and the reference density patterns; and gradation correcting unit for performing a gradation correction.

Abstract: A method of registering a print between print stages in a printing system is provided. The method comprises: printing a first part of a digital image on a substrate with a first print engine, wherein the first part of the digital image includes a plurality of reference features; scanning image content on the substrate as it is readied for the second print engine; determining the actual positions of the reference features; using the actual positions of the reference features to determine desired adjustments for the second part of the digital image; applying electronic registration according to the desired adjustments to modify image content of the second print to be aligned with content already on the substrate; and printing a second part of the digital image on the substrate.

Abstract: Methods and systems are provided for controlling a printing device in the presence of reload defects. According to a first embodiment, a controller is provided to manage the printing of scheduled control patches immediately after an image of a print job. Accordingly to a second embodiment, a controller is configured to manage the printing of an image or a print job immediately after a control patch.

Abstract: A device and a method for improving the quality of prints using a printing device and system for carrying out a print job with a digital printing machine, preferably with a printing machine that works with a toner, in particular with an electrophotographically operating printing machine, whereby the sheets (1) are preferably printed by recto-printing and verso-printing, whereby the sheets (1) to be printed are divided into batches, and whereby, in the case of batches that are incompletely occupied with sheets (1), the slots of the missing sheets are replaced by an approximately sheet-sized toner field (3) on the transport belt (4) for the sheets.

Abstract: Disclosed herein are a method and a printing apparatus implementing the method to minimize cross-process direction non-uniformities of color images in printed documents. When printing images on a photoreceptor, halftone test patches are generated for each color. A first halftone cell orientation (of dots) of the test patches and their corresponding color image data is determined. The halftone cells of test patches may be provided or rotated to a second orientation (or angle or degrees) for printing in an inter-document zone of the photoreceptor, while the first orientation of the color image data in the document image area of the photoreceptor remains the same. Errors or non-uniformities (e.g., with TRC correction) caused by sensor misreading of test patches at specific orientations in the cross-process direction are substantially eliminated, thereby providing output images without streaks or visible errors.

Abstract: A method and system for improved image quality using an image quality matching method is used to match the optical density of single prints produced on multiple print engines by first sensing the optical density of a first image produced on a first print engine and then sensing the optical density of a second image produced on a second print engine before comparing the optical densities and determining if they are substantially equal. If they are not equal set points and exposures are adjusted on one or both print engines until the differences between the optical densities is less than 0.05, preferably 0.03. The density is changed by adjusting the initial voltage on the primary imaging member of at least one print engine and/or by adjusting the exposure of the primary imaging member of at least one print engine.

Abstract: An image forming apparatus includes: an image carrier rotates in a predetermined direction; a correction image forming unit forming correction images on the image carrier in the predetermined direction; and a cleaning roller configured to clean the correction images on the image carrier. With respect to all values ranging from 1 to an arbitrary value n, a positive integer N which satisfies following expression for each of n exists: (T×N+L)/n?R/V?(T×(N+1)?L)/n, where R represents a circumferential length of the cleaning roller, L represents a length of each of the correction images in a moving direction of the image carrier, T represents a formation interval of the correction images in the moving direction of the image carrier, and V represents a ratio of a peripheral speed of the cleaning roller to a moving speed of the image carrier.

Abstract: This is a method for placing test patches along the surface of a photoconductive belt. A novel feature of this invention is locating optimum times and locations for placing the test patches by rotating the belt backwards after the first normal forward rotation of the belt.

Abstract: An image forming system includes an image forming unit, a measurement unit, a correction unit, and an inhibition unit. The image forming unit forms an image. The measurement unit measures densities of a plurality of density patches formed by the image forming unit. The correction unit performs a density correction for the image forming unit based on the densities of the plurality of density patches measured by the measurement unit. The inhibition unit determines whether or not the densities of the plurality of the density patches are normal based on at least one of the densities of the plurality of density patches, and, if the densities are determined not to be normal, inhibits the correction unit from performing a density correction based on the densities of the plurality of density patches determined to be not normal.

Abstract: A printing device configured to print a diagnostic plot, the diagnostic plot comprising a cockle pattern, a main media advance pattern, and a secondary media advance pattern, wherein the cockle pattern, main media advance pattern, and secondary media advance pattern are for providing feedback and for adjusting printing characteristics associated with the printing device. A method of adjusting vacuum levels in a vacuum system of a printing device comprising generating a diagnostic plot on media; the diagnostic plot including a cockle pattern, a main media advance pattern, and a secondary media advance pattern, and accepting adjustments to printing parameters on the printing device based on printing defects displayed on the diagnostic plot.

Abstract: In an image forming apparatus, a controller performs development of toner patterns corresponding to a first halftoning method and a second halftoning method. One of the toner patterns contains first patch images for the first halftoning method, and another one contains second patch images for the second halftoning method. The controller performs development of only one out of both a first patch image (one of the first patch images) and a second patch image (one of the second patch images) if an absolute value of a difference between the number of dots in the first patch image and that in the second patch image is equal to or less than a predetermined value and an absolute value of a difference between the number of dot-level edges in the first patch image and that in the second patch image is equal to or less than a predetermined value.

Abstract: A method for monitoring an image printing system that prints color images on an image bearing surface movable in a process direction is provided. The method includes placing marking material to form a row comprising a plurality of registration marks on the image bearing surface, wherein each row of registration marks extends along a cross-process direction transverse to the process direction; detecting a position of each registration mark using a linear array sensor extending in the cross-process direction, wherein the position of each registration mark is detected in both the process and cross-process direction; determining a process direction misregistration between the registration marks of each row in the process direction and cross-process direction misregistration between registration marks from each of the rows.

Abstract: An image forming apparatus is provided that forms an image using developers of different tone and the same hue. When forming images for measurement for density control, the apparatus performs density control by forming a greater number of density levels of an image for measurement developed using a light developer than the number of density levels of an image for measurement developed using a dark developer. Thus, even if the amount of applied light developer may fluctuate, the fluctuation can be compensated to prevent the occurrence of pseudo-contours that lower image quality.

Abstract: In an image forming apparatus, the number of components and a size of the apparatus is reduced by realizing both functions for detecting a toner patch image to perform image quality adjustment and for performing precise color adjustment depending on a sheet color with one color sensor. The color sensor is disposed in a vicinity of a transport belt, a reference toner image is formed on the transport belt at a predetermined timing. A color of the reference toner image formed on the belt is detected by the color sensor to adjust development conditions. Further, the sheet is transported in a state where the transport belt is separated from a photoreceptor drum, and the sheet color is detected by the color sensor, and thereafter the transport belt touches the photoreceptor drum to transport the sheet to a transfer portion.

Abstract: To solve a problem of an increase of kinds of toner patches required for an adjustment accompanying an increase of kinds of half tones to be coped with that results from an intention of acquiring more stable image by forming the toner patches between paper sheets. It becomes possible to form more toner patches and therefore to deal with an increase of kinds of toner patches by correcting a density in a space of a line count obtained by summing up a line count corresponding to a space between paper sheets during a continuous printing operation, a rear-end blank line count of the n-th page, and a leading-end blank line count of the (n+1)th page that is enabled by comparing the size of a recording material and the size of pixel data and thereby by identifying a blank portion of the recording material.

Abstract: The present invention aims to provide an image forming apparatus and the like that perform a highly-accurate tone correction in a relatively short time and includes the following: a pattern former, with use of each image forming unit, on a sheet, forming tone patches in the main or sub scanning direction (41k,c,y,m) and aligning markers, which indicate positions of the tone patches, in the same direction as the tone patches (42k,c,y,m); a pattern reader reading the sheet with the tone patches and markers formed thereon; a coordinate determiner determining coordinates of the tone patches in the direction of the aligned tone patches based on the read markers (42k,c,y,m); a density determiner determining densities of the tone patches (41k,c,y,m) read based on the determined coordinates; and an updating part updating the tone correction table based on relationships between the determined densities and tone levels.

Abstract: An image forming apparatus includes a plurality of image forming units, a patch forming unit which actuates the respective image forming units to form density detection patches of the respective colors, a density detecting unit that detects a density of the density detecting patches, a condition correcting unit that controls the density detecting unit to detect the density of the density detecting patches of the respective colors, and corrects the image forming conditions based on respective deviations, a patch re-forming unit that, for each color for which the respective deviation is greater than a threshold value, generates a re-formed density detecting patch of the color using the respective image forming condition previously corrected by the condition correcting unit, and a condition re-correcting unit that controls the density detecting unit to detect a density of the re-formed density detecting patch and re-correct the respective image forming condition.

Abstract: A determining unit determines whether a difference between a temperature value and a temperature detected by a temperature detecting unit is equal to or larger than a first value. A pattern forming unit, when the determining unit determines that the difference is equal to or larger than the first value, forms a pattern for measurement including sub-patterns of a plurality of colors on a transfer medium. A calculating unit calculates a misregistration-amount for each sub-pattern based on a detected position of the sub-pattern and a predetermined position of the sub-pattern. A correcting unit corrects a position on which the sub-pattern is to be formed based on the misregistration-amount. An image forming unit forms an image for each color factoring in corrected position for each color.

Abstract: An image forming apparatus includes a transport part which includes a transport belt to transport a printing medium, an image forming part which transfers a toner to form a color image, and a controller which controls the image forming part to form a test image for color registration of the image forming part on the transport belt while an image is formed for a plurality of printing media. Thus, both a test image and a plurality of printed media are formed during a single printing process.

Abstract: Methods and systems herein provide for printing a plurality of variations of a test image utilizing different values of a print quality parameter for print quality analysis of a printer. A print quality parameter is selected that modifies a print quality of the printer when printing a test image. A range of values for the print quality parameter is defined to utilize when printing the test image. A plurality of variations of the test image are printed based on the range of values defined for the print quality parameter, which allows for an analysis of the print quality of the printer by the user.

Abstract: A tandem-type color image forming apparatus forms a toner pattern and toner markers on an intermediate transfer member. Tone levels in the toner pattern vary in a sub scanning direction, and the toner markers which are a same color with the tone pattern each oppose, in a main scanning direction, a different one of the tone level portions in the toner pattern, each tone level portion representing a different one of the tone levels. Positions of the toner markers in the sub scanning direction are determined to detect densities in the toner pattern corresponding to the determined positions. Tone of image data is corrected in an image formation based on a relationship between the densities and the tone levels corresponding to the determined positions.

Abstract: When an image forming job is completed that records onto a recording sheet an image formed on a photoconductor drum and conveys the recording sheet, a simple process control is carried out that forms some filled patch images with using some toners. After the simple process control is carried out, a determination is carried out, in accordance with a charge control value of a charge roller adjusted by the simple process control (a voltage value applied on the charge roller), whether a formal process control should be carried out or not that forms many patch images with using much toners. The formal process control is additionally carried out, when the determination means so.

Abstract: An image forming apparatus that is capable of generating highly accurate read timing of a patch image, thereby achieving highly accurate density adjustment and improving color stability. A patch image for color adjustment is read in read timing generated when a trigger bar is detected. The patch image and the trigger bar that are to be read by a color sensor are formed on a transfer material. Image formation is executed by a printer controller in an image forming condition set differently for the trigger bar and for the patch image.