Abstract: A color registration method, system, and computer program product generally includes a plurality of imaging stations and one or more MOB (Marks-On Belt) sensors. An indication is initially provided to each imaging station among the imaging stations, which colors among a plurality of colors associated with said color registration system are active. Next, an arbitrary imaging station among the imaging stations can be assigned as a reference color. Thereafter, the arbitrary imaging station can be instructed to write an appropriate color pattern to replace marks associated with any imaging among imaging stations not enabled with the marks with respect to said reference color in order to thereby produce a resulting color ensemble that is detectable by one or more MOB sensors.

Abstract: An image forming apparatus includes an image forming unit that forms a color image in which a plurality of color component images are superimposed; and a formation controlling unit that allows the image forming unit to form images for adjustment of formation positions of the respective color component images. The formation controlling unit allows the image forming unit to form, for each color, a plurality of adjustment images having different tilts with respect to a main scanning direction. A shift of a detected position of each adjustment image from a reference position in which each adjustment image should be formed is calculated, a tilt and an intercept of a regression line that uses the reference positions and the calculated shifts as variables are calculated, and a shift in the main scanning direction and a shift in a sub-scanning direction are determined based on the calculated tilt and intercept.

Abstract: A tandem type color image forming apparatus which executes color misregistration correction, including: a detecting section which detects a width of a transfer sheet; an image forming section having an image carrier, on which arranged side by side are an image area where formed is an image for transfer and a non-image area where formed is an imprint image; and a control section which selects a complex or a single correction mode based on the transfer sheet width, to execute correction processing; where the complex correction mode is an operation mode of forming in parallel the image for transfer in the image area and the imprint image in the non-image area, and the single correction mode is an operation mode of suspending to form the image for transfer in the image area, and executing only to form the imprint image in the non-image area or in the image area.

Abstract: An image formation apparatus is disclosed to form a color image for imprinting, and the color image for imprinting is imprinted to an imprinting medium. The image formation apparatus includes an image formation unit for forming plural sets of marks for position error compensation for compensating for a position error of the different colors, which position error is generated when forming the color image on the conveyance belt, a detection unit for detecting position information about positions of the sets of marks for position error compensation formed on the conveyance belt by the image formation unit, a control unit for performing a position error compensation process based on the position information detected by the detection unit, and a storage process of storing the position information of the sets of the marks for the position error compensation detected by the detection process.

Abstract: A system for handling media sheets is provided which comprises a plurality of hardware components including a first image marking engine operative to mark media sheets, and a second image marking engine operative to mark media sheets. In addition, the plurality of hardware components can include a first object delivery path operative to transport media sheets presented by the first image marking engine to a first destination, and a second object delivery path operative to transport media sheets presented by the second image marking engine to a second destination. The first and second destinations may be a single destination, separate destinations, or interchangeable destinations. One of the first and second delivery paths can be redundant.

Abstract: A first correction pattern and a second correction pattern are formed on an endless conveyor belt. The first correction pattern is located ahead of the second correction pattern on the conveyor belt with respect to the direction of movement of the conveyor belt. A sensor detects positional information of the correction patterns. A timing changing unit (controlling unit) changes a detection timing of the second correction pattern from a time point at which the sensor detects the second correction pattern.

Abstract: A drive control unit for controlling speeds of driving parts based on a target speed, includes a detecting part to detect speed fluctuations of each of the driving parts when the speeds of the driving parts are controlled based on a common target speed, a storage part to store speed fluctuation profiles of each of the driving parts created based on the detected speed fluctuations, an extracting part to extract a speed fluctuation profile having a largest amplitude of the speed fluctuation profiles stores in the storage part, a calculating part to calculate difference profiles of the driving parts, corresponding to differences between the extracted speed fluctuation profile and the speed fluctuation profiles of each of the driving parts, a setting part to set the difference profiles of the driving parts as new target speeds of the driving parts, and a control part to control the speeds of the driving parts based on the new target speeds.

Abstract: An image forming apparatus includes a detection unit configured to cause a light emitting device to emit light, to cause a light receiving device to receive the light reflected by an object, and to produce a detection signal having a varying signal level responsive to an intensity of the received reflected light, a color misalignment correction unit configured to correct color misalignment resulting from positional misalignment between the developer images of respective colors on a transfer body by controlling an exposure unit in response to detected data indicative of the developer images detected in the detection signal, and an adjustment unit configured to identify a plurality of peak positions in the detection signal detected with respect to a single developer image and to adjust the detected data indicative of the developer images detected in the detection signal in response to difference in the peak positions.

Abstract: A color image forming device comprises a plurality of first image support mediums, a scanning exposure unit, a second image support medium, a second-image-support-medium transport unit, a transfer unit, a correction-pattern-image forming unit, a pattern measurement unit, and a control unit. The correction-pattern-image forming unit is configured to reduce the total time for forming a sequence of correction pattern images of color components.

Abstract: An image forming method includes forming toner images on first and second image bearing members; transferring a first toner image on the first image bearing member and a second toner image on the second image bearing member, in mutually superposed manner, onto a recording material; heating the first and second toner image thereby fixing the same to the recording material; detecting alignment marks on the first and second image bearing members in the course of a continuous job for continuously forming images; controlling relative positions of the first toner image and the second toner image, based on a result of detection of the alignment marks; and increasing a frequency of execution of the relative position control in the continuous job, as the recording material to be subjected to image formation in the continuous job has a smaller width in a direction perpendicular to a transport direction of the recording material.

Abstract: A technique can define a right position for forming a toner image on the transfer surface of an intermediate transfer body regardless of the size and the number of the sheets on which toner images are to be transferred. An image forming apparatus for forming a toner image on the transfer surface of an intermediate transfer body by correcting the position for forming the toner image comprises a data acquisition section that acquires predetermined data relating to the printing data for forming an image on a sheet and a correction section that corrects the predefined value for defining the position for forming the toner image on the transfer surface according to a predetermined correction value corresponding to the predetermined data acquired in the data acquisition section.

Abstract: After detecting a speed fluctuation pattern per rotation of a photosensitive drum, a process that forms an image based on image data while causing the photosensitive drum to rotate at a nonstandard linear speed is executed as an image forming process by driving a process driving motor that drives the photosensitive drum to curb a speed fluctuation of the photosensitive drum by using a driving speed fine tuning pattern. Before executing the image forming process, a fine-tuning-pattern correcting process is executed for correcting the driving speed fine tuning pattern of the process driving motor, based on the nonstandard linear speed.

Abstract: An image forming apparatus includes a first registration mark detection unit, second registration mark detection unit, CPU, and first registration mark time difference storage. If the width (tp) of the first registration mark signal detected by the second registration mark detection unit is equal to or smaller than a set value, the CPU directly uses, as an enable signal for controlling paper conveyance, the first registration mark detection signal detected by the first registration mark detection unit. If the width (tp?) of the first registration mark signal detected by the second registration mark detection unit is equal to or larger than a set value, the CPU controls a paper conveyer by setting, as a correct first registration mark position, a position shifted by tE measured from an error signal, from the first registration mark detection signal detected by the first registration mark detection unit.

Abstract: A feeding unit that feeds a medium, a plurality of image carriers arranged in parallel along a moving direction of the medium, a developer image forming unit that forms a developer image on the plurality of image carriers, and a transfer unit that transfers the developer image formed on the plurality of image carriers onto the medium is described. The developer image forming unit forms a first developer image on a first image carrier of the plurality of image carriers, the first developer image being used for transferring a first pattern at a first interval on the medium along the feeding direction. Also, the developer image forming unit forms a second developer image on a second image carrier of the plurality of image carriers, the second developer image at the first interval and a second interval alternately on the medium along the feeding direction.

Abstract: A method for detecting and correcting misregistration between a plurality of separations printed by a printing apparatus, comprising: producing a calibration print output on a substrate, the calibration print output including at least one calibration pattern, wherein the at least one calibration pattern translates horizontal misregistration into a detectable indicator of misregistration in a process direction; detecting misregistration; and, performing a fine adjustment of the horizontal position of at least one of the separations using the at least one calibration pattern.

Abstract: A lateral position of a photoreceptor belt is detected by at least a first sensor and a second sensor, respectively located near a first imager and a second imager. The detected lateral positions of the photoreceptor belt by the first sensor is compared to the detected lateral position of the photoreceptor belt by the second sensor. Based on this compared difference, a correction is applied to the position of the second imager relative to the photoreceptor belt. To apply the correction, the location of the start of scan (SOS) of the respective imagers is moved.

Abstract: A color image forming apparatus including a plurality of image forming devices, a transfer device including a transfer belt, a test pattern forming device configured to form, on the transfer belt, a test pattern including a plurality of marks formed by the image forming devices, an optical sensor configured to read the plurality of marks, and a checking device configured to determine whether reading by the optical sensor is performed correctly or not.

Abstract: An apparatus to control color registration and image density and a method of calculating a color registration error. The apparatus includes registration marks formed on a transfer belt such that each of the registration marks includes a scan direction component and a slanting direction component at an angle with respect to both the scan direction and the cross-scan direction. The apparatus further includes image density marks formed on the transfer belt, having predetermined image densities, and a registration and image density sensor provided above the registration marks and the image density marks to radiate beams onto the registration marks and the image density marks. The sensor receives beams reflected from the registration marks and the image density marks to produce detection signals, and obtains registration information and image density information from the detection signals.

Abstract: Exemplary embodiments provide an apparatus, method, system, computer program and product, each capable of controlling a timing for starting image formation such that when forming a preceding image and a following image, a timing for starting formation of the following image is adjusted based on a timing for starting the preceding image.

Abstract: In an image recording apparatus, reference patterns are provided on a surface of a transport belt that transports a recording medium such as paper attracted thereto to image recording sections defined by recording heads. It is arranged such that the reference patterns are detected while being transported as the transport belt is driven, and a speed change of the transport belt and a position shift in a direction perpendicular to the transporting direction of the transport belt are calculated based on information resulting from the detection, thereby controlling ejection timing and ejection position of ink droplets ejected from the recording heads.

Abstract: Image data are inputted from a data processing means (23) into storage means (24) so that light emitting elements on one line (28a) of a light emitting element (yellow) line head (28) are actuated according to signal outputted from a shift resistor (24a) so as to expose pixels on an image carrier. At a point of time when the pixels reach a position corresponding to the light emitting elements in a next line (28b) by moving the image carrier in a direction of arrow X, the image data are transmitted to a shift resistor (24b) and then outputted to the line (28b) so as to expose the pixels again. The image data are transmitted among the shift resistors sequentially by moving the image carrier, thereby achieving the multiple exposure of the same pixels.

Abstract: A system and method for determining a color separation registration error in a multi-color printing system are provided. The system and method provide for instructing first and second color separations to mark a substrate with first and second fine-periodic-patch images to determine color separation registration error(s). The system and method further provide for determining whether at least an about half-period color separation registration error exists between the first and second color separations.

Abstract: Light quantity is adjusted in an image forming apparatus including an image carrier by forming a pattern on the image carrier, detecting a light quantity of a reflecting light from the pattern and outputting a voltage, reading the light quantity of the reflecting light from the pattern detected once based on a present light quantity set, calculating from the light quantity read, a set light quantity corresponding to a target output voltage for printing, and setting the set light quantity calculated.

Abstract: An image forming apparatus in which a plurality of color component images of different colors, which include a reference color (e.g. black) serving as a reference and adjustment colors (e.g. cyan, magenta and yellow) to be adjusted, are formed on respective photosensitive drums and then transferred to a transfer belt. Respective positions of the color component images transferred to the transfer belt are detected by a CCD. Timing adjustment can be performed so that the difference between the detected position of each of the color component images and a prescribed position is not more than a predetermined value, based on the reference color image as the reference. In this case, the color component images are formed on the corresponding photosensitive drums with the same timing by utilizing a single polygon mirror.

Abstract: A printer includes a first transporting belt that transports a print medium and a second transporting belt that receives the print medium from the first transporting belt and further transports the print medium. A liquid ejection head ejects liquid according to a liquid-ejection timing signal to the print medium transported by the first transporting belt and the second transporting belt. A signal generator outputs the liquid-ejection timing signal according to a first signal and a second signal that correspond to the travel of the first and second transporting belts, respectively. When the phase difference between the first and second signals has a predetermined threshold value or less, the signal generator switches from outputting the liquid-ejection timing signal according to the first signal to outputting the liquid-ejection timing signal according to the second signal.

Abstract: This invention enables an image forming apparatus to perform highly precise misregistration detection without causing increased downtime or increased cost. For this, the image forming apparatus according to the invention comprises a detection unit for detecting a misregistration detection pattern formed on an endless belt. The employed misregistration detection pattern includes a first pattern array formed with a misregistration detection color or a reference position color, and a second pattern array formed with a misregistration detection color or a reference position color. The misregistration detection pattern is configured in a way that the first pattern and the second pattern have different shapes, and that the color order of the first patterns in the first pattern array and the color order of the second patterns in the second pattern array are different.

Abstract: A color image forming apparatus includes a coordinate conversion part, which converts a ordinate value, for executing a misregistration correction in the unit of a pixel; a gradation conversion part, which converts a gradation level, for executing a misregistration correction in a unit less than a pixel; and a judgment part, which detects a feature of the image and judges whether or not to execute the misregistration correction in a unit less than a pixel by the gradation conversion part. The judgment part compares the gradation level in an object pixel and a pixel adjacent in a sub-scanning direction, thereby judging whether or not to execute the misregistration correction in a unit less than a pixel. Thus, the invention enables to distinguish an image to be subjected to the registration correction in a unit less than a pixel and an image not to be subjected to such correction in a simple manner and also in consideration of the image color.

Abstract: An image forming apparatus includes a light source that emits a light beam in a main scanning direction according to image data to be used for image formation, a control unit that controls the light source, and detectors that detect the light beam. The main scanning direction is divided into areas and a cycle of a pixel clock is corrected in each area independently based on detection results of the detectors so as to correct an image position and image magnification.

Abstract: Image forming apparatus includes image forming units, an intermediate transfer member, a mark detecting mechanism, a counter, and a controller. The intermediate transfer member have marks. A distance between nth and (n+1)th marks is substantially equal to or smaller than a difference between a distance from a write position of the nth image forming unit to a primary transfer position of the (n+1)th image forming unit and a distance from a write position of the (n+1)th image forming unit to the primary transfer position of the (n+1)th image forming unit. The controller controls the nth image forming unit to start writing when the mark detecting mechanism detects the nth mark and the counter reaches a predetermined count value, and controls the (n+1)th image forming unit to start writing when the mark detecting mechanism detects the (n+1)th mark and the counter reaches another predetermined count value.

Abstract: An image forming apparatus capable of decreasing the image unevenness of a superimposed image at the time of forming starting (head) lines of the images in respective colors with different beams in order to decrease a shift of a superimposed image. Let a position, where an image in a first color is formed with a beam A as a leading beam, be (a). Let a starting position of formation of an image in a second color be (b), and one dot (line) of shift arises in the superimposed image. In order to decrease the shift of the superimposed image, image formation is performed with selecting a beam B as a beam which writes a head of the image (c). When image formation is performed for color shift reduction with changing a leading beam for each color image, tonality correction is performed to each beam for subsequent images so as to decrease image unevenness due to the difference between shapes and exposure power of respective beams.

Abstract: Reflex writing is a group of algorithms developed to maintain color registration in xerographic systems using multiple imagers, in which sequential color separations are written based on events in the spatial domain. The imaging system includes a raster output scanner imager for the black station and a light emitting diode bar for the color station. A simulated machine clock signal is generated based on a running average of a plurality of actual machine clock periods determined from pulses received from a photoreceptor module drive roll encoder. For each black scanline written the distance the belt travels is tracked using the simulated machine clock signal, and when the black latent image scanline has traveled the known distance between the two imagers, the light emitting diode scanline is written registered with respect to the raster output scanner scanline.

Abstract: If a velocity calculated by a velocity calculating unit deviates from a normal range, a target velocity is used as a feedback amount, an actuation amount corresponding to a deviation Ve=0 between the feedback amount Vf=Vt and the target velocity Vt is calculated, and a driving power corresponding to this actuation amount is supplied to a motor. A conveyor belt can be driven stably without causing irregularity in a speed of the conveyor belt.

Abstract: The positioning of image data written along a laser beam scan path in the scan direction, e.g., the margin and/or line length is adjusted in a manner that compensates for changes in the laser beam scan path as a result of one or more operating conditions, such as changes in temperature. Further, the positioning of image data in the process direction may be adjusted in a manner that compensates for changes in the laser beam scan path as a result of the one or more operating conditions.

Abstract: An image forming apparatus for forming color images may include at least two or more colors, having a function of magnification correction of image size by one page unit, the image forming apparatus including: an image carrier; a polygonal mirror rotator independently provided for each color; and a controller which simultaneously conducts first control for changing rotation speed of the polygonal mirror rotator in order for changing image size in a sub-scanning direction perpendicular to a main scanning direction, and second control for correcting a correction amount for color registration error depending on magnification correction of image size, and for adjusting a rotating phase of the polygonal mirror rotator depending on the corrected correction amount for color registration error.

Abstract: Systems and methods are provided for detecting process direction registration errors in a printer. The errors are detected by analyzing a metric of a dash minimum response obtained from a test pattern. The test pattern contains dashes. At least one dash is shifted in the process direction in relation to another dash.

Abstract: The recording medium conveyance amount measurement method includes the steps of: recording a first test pattern having two straight lines including at least one straight line which is not parallel with respect to a conveyance direction of a recording medium and a direction perpendicular to the conveyance direction, onto the recording medium; conveying the recording medium in the conveyance direction; recording a second test pattern having two straight lines including at least one straight line which is not parallel with respect to the conveyance direction of the recording medium and the direction perpendicular to the conveyance direction, onto the recording medium; and reading in the first and second test patterns and calculating a conveyance amount of the recording medium.

Abstract: A printer processor prints out two sheets of test prints by printing a test pattern on two recording sheets of different lengths. The test pattern consists of eight straight-linear lines that are parallel to a main scan direction or a sub scan direction of an exposure section. Dimensions of designated portions of the test pattern are measured on each of the test prints, to detect skew characteristics of the recording sheets, deviations of print starting positions in the main and sub scan directions and fluctuations in transport speed of the recording sheets. Based on the detected values, a skew correcting section, the exposure section and a conveyer device for the recording sheets are controlled to correct skew of the recording sheets, the print starting positions in the main and sub scan directions and the transport speed.

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is representing by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted

Abstract: An image forming apparatus including a memory device configured to prestore control information and registration pattern data, a traveling member, a toner pattern forming device forming a toner pattern, which includes a plurality of marks of a plurality of color components, on the traveling member according to the registration pattern data. A position detecting device detects each of the plurality of marks in the toner pattern. A control information correcting device corrects the control information according to a difference among positions of the plurality of marks, and a main-scan registration correcting device adjusts, based on the corrected control information, a start-of-write timing in the main scanning direction in a unit of a pixel clock cycle and adjusts a writing timing in the main scanning direction in a unit smaller than the pixel clock cycle by controlling a phase of the pixel clock cycle.

Abstract: An image forming apparatus forming a color image with color toners includes a plurality of image forming members, an image transfer member, a plurality of sensors, a calculator, an edge extractor, a counter, and a misregistration corrector. The plurality of image forming members forms a plurality of test patches. The image transfer member receives the test patches. The plurality of sensors detects the test patches. The calculator performs a logical operation, e.g., an exclusive-OR operation, upon detection signals output by the sensors. The edge extractor detects edges and generates edge signals based upon an output signal of the calculator. The counter counts clock pulses with respect to the edge signals to determine a length of each of the test patches. The misregistration corrector calculates time lags among the detection signals based on count values counted by the counter for the test patches and correct misregistration of the color image based on the calculated time lags.

Abstract: An image forming apparatus includes an input unit that inputs an image forming job, a raster image generating unit, a transport path, a plurality of image forming engines, a calculating unit that calculates the displacement amount between the formation position of the pattern formed by each image forming engine and an ideal formation position thereof, and a controller that supplies each of the plurality of image forming engines with a driving signal instructing formation of a blank image during the time period when the calculated displacement amount is larger than a second threshold value, supplies each of the plurality of image forming engines with a driving signal instructing formation of the image corresponding to each raster image generated by the raster image generating unit and a preset mark when the displacement amount is smaller than the second threshold value.

Abstract: A color image forming apparatus including a plurality of image forming devices attachable to and detachable from a housing, a transfer device including a transfer belt, an exchange detecting device configured to detect exchange of the image forming devices, a test pattern forming device configured to form, on the transfer belt, a test pattern including a plurality of marks formed by the image forming devices, when the exchange detecting device detects an exchange of the image forming device, an optical sensor configured to read the plurality of marks, and a checking device configured to determine whether reading by the optical sensor is performed correctly or not.

Abstract: A color image forming apparatus includes a pattern forming mechanism configured to form a pattern for fine adjustment and a pattern for rough adjustment on a transfer medium, a detection mechanism configured to detect the pattern formed thereon, a displacement calculation mechanism configured to obtain a predetermined value and preset reference values, to calculate the amount of displacement based on the detected pattern and the preset reference values, and to determine whether or not the amount of the displacement is equal to or less than the predetermined value, and a displacement correction mechanism configured to correct the displacement based on the calculation.

Abstract: An image forming apparatus includes an intermediate transfer member, a sensor, and two image forming units. Each of the image forming units includes an image carrier, an image writer, two development rollers, and a switcher. The image writer writes an electrostatic latent image on the image carrier. Each of the development rollers selectively driven by the switcher visualizes the electrostatic latent image to form toner images in four colors. The toner images are transferred and superimposed onto the intermediate transfer member to form a color toner image. The color toner image is transferred onto a transfer sheet. One or more marks are formed on the intermediate transfer member. The sensor detects one of the marks. The image writer starts writing in synchronism with a sync clock signal of the image writer output immediately after the sensor detects the mark or output after a predetermined time period elapses after the sensor detects the mark.

Abstract: An image forming apparatus including a light scanning device configured: to store in advance a predetermined base correction time; initiate optical image writing for a first round of rotation of an endless intermediate transfer member onto a latent image bearing member included in a first visible image forming unit based on a standard angle detection signal detected after a time Te determined as a time elapsed by a base correction time t1 from a time Ta; to correct a phase, during a period between a time Tc and a time including a time Tc and the base correction time t1, based on a time lag dt2 and a time lag dt1; and to initiate optical image writing for a second round of rotation of the endless intermediate transfer member onto the latent image bearing member included in the first visible image forming unit.

Abstract: There is described an apparatus, which includes an image-forming section to form a multicolor image on a recording medium by recording the unicolor images in such a manner that the unicolor images overlap each other, based on printing image data sets of them, and a controlling section that determines at least a sub-scanning velocity in a sub-scanning direction relative to the recording medium, corresponding to a printing magnification factor, so as to adjust an output-start timing in the sub-scanning direction for every printing image data set, in response to the sub-scanning velocity determined in advance. Further, the controlling section also determines a main-scanning velocity in a main-scanning direction, corresponding to the printing magnification factor, so as to adjust output-start timings in both the main-scanning direction and the sub-scanning direction for every printing image data set, in response to the main-scanning velocity and the sub-scanning velocity, both determined in advance.

Abstract: An image forming apparatus which is capable of forming an excellent image while suppressing reduction in productivity to a minimum even when an abnormality occurs in detection of an HP mark on an intermediate transfer member. When there occurs abnormality in detection of any of HP marks, an alternate signal is generated in place of a signal associated with a mark the detection of which is determined to be abnormal, and image formation is carried out with reference to the time of normal HP mark detection and the alternate signal.

Abstract: In an image forming device, a correction unit corrects image formation operation based on a plurality of correction patterns. A pattern creation unit forms an electrostatic latent image of the correction patterns on a photoconductor and transferring the image to an intermediate transfer body to form the correction patterns thereon. A pattern detecting unit detects the correction patterns formed on the intermediate transfer body. A speed detecting unit detects a movement speed of the correction patterns on the intermediate transfer body are moved. A timing holding unit computes a set value of detection start timing for starting detection of each correction pattern to hold the set value. The correction unit is provided to determine, in advance of correcting image formation operation, a detection start timing based on the movement speed and the set value.

Abstract: A printing apparatus in which it is possible to set proper correction data by eliminating an erroneous operation of an operator is constructed. A code indicating the type of used printing paper P is formed on a test chart TC. When the correction data is generated, a printing paper type specifying section 25B of correction data generating means 25 judges whether the printing paper is proper or not based on the code, by setting the test chart TC on a flatbed scanner 5 and performing pre-scan on it. If it is the test chart TC using proper printing paper, then the density data in a plurality of pixel lines constituting the chart is acquired and the correction data is generated by performing the main scan, and the correction data is stored in a correction table 35 in association with the type of the printing paper.

Abstract: An image forming apparatus includes a counter that counts the accumulated number of predetermined printed recording sheets and an image correction controller that performs an image correction operation when the accumulated number of recording sheets reaches a predetermined number. The image forming apparatus is configured to advance an execution timing of the image correction operation, depending on its predetermined operating status.