Abstract: The present invention provides an image processor for outputting image data to an image forming device forming an image with use of a recording material having a plurality of color components. The processor comprises a component determining a region having higher brightness than predetermined brightness and a region having lower brightness than the predetermined brightness in the image data based on the image data and a component adjusting saturation so as to reduce density values of color components other than a color component having a maximum density value among the plurality of color components of the recording material to increase saturation in a region having brightness determined to be high and reduce density values of color components other than a color component having a minimum density value among the plurality of color components of the recording material to decrease saturation in a region having brightness determined to be low.

Abstract: An apparatus having an operative mode and a non-operative mode with a method for counting events with a volatile counter and a non-volatile electronic memory having a number N of memory areas, includes counting events with the volatile counter, when the count value has been incremented by a predetermined number M or when the apparatus passes into the non-operative mode, saving the count value to one of the memory areas, with cycling switching of the memory area into which the count value is written; and when the apparatus passes into the operative mode, initializing the counter with the maximum of the count values stored in the N memory areas.

Abstract: An image forming apparatus has a job-content recognition device for judging whether a number inputted as the number of print copies to be made is larger or smaller than a predetermined reference value; a print-data recognition device for judging whether or not inputted print data include image data and/or graphic data; and a control device for controlling executions of image stabilization control in a printing section. The control device sets a predetermined period as intervals among executions of the image stabilization control, and sets a period shorter than the predetermined period as the intervals among executions of the image stabilization control when the number inputted as the number of print copies to be made is larger than the predetermined reference value and also the inputted print data include image data and/or graphic data.

Abstract: A control device for generating a second trigger with a delay of a predetermined time from generation of a first trigger, said control device having; a counter for counting numbers from 0 to n?1 at a frequency with cycles of a first period; a control section, which operates at a frequency with cycles of a second period that is longer than the first period, for calculating a remainder of a division by adding a number of counts of the counter corresponding to the predetermined time to a count value of the counter at the time of generation of the first trigger and by dividing a result of the addition by n; and an output section for outputting the second trigger at a time when the count value of the counter becomes equal to the remainder.

Abstract: A direct printing method and an image forming device for performing the direct printing method are provided. The image forming device includes an image forming body and a controller. The image forming body includes a plurality of electrodes, and the controller controls to operate at least some of the plurality of electrodes at different times and print a single line image.

Abstract: An image forming apparatus includes a moving unit including a conveyer belt which moves a printing medium, an attraction unit to attract the printing medium to the conveyer belt, a transferring unit to transfer developer onto the printing medium, a power supply which supplies transfer power and attraction power to the transferring unit and the attraction unit, and a controller which controls the power supply to supply only one of the transfer power and the attraction power in accordance with a location of the printing medium.

Abstract: When an input image is to be formed on a sheet conveyed to a transfer roller, the exposure section is controlled and deviation correction is performed to offset the image forming position across the width of the sheet in response to the result of detection by a deviation sensor. By contrast, when pattern images are to be formed on a sheet in response to the instruction of the main control section, the image forming control section does not perform deviation correction in the process of forming a pattern image.

Abstract: According to one embodiment, a cleaner-less mechanism is provided only in a black image forming unit, and a cleaning apparatus is provided in a color image forming unit. Otherwise, when an image adjustment function is executed, the number of operations of forming an image adjustment pattern corresponding only to a black developing agent is reduced.

Abstract: An image forming device includes an image forming section; a storage section that stores a target darkness of a standard image; a measurement section that measures the darkness of the image formed by the image forming section; a user calibration section that causes the image forming section to form a standard image causes the measurement section to measure the darkness of that standard image, and if there is a discrepancy between the darkness of the standard image specified by the measurement of the physical quantity and the target darkness stored in the storage section, adjusts the image formation conditions to eliminate the discrepancy; a manual darkness adjustment section that changes the image formation conditions to content that is specified by the user; a control section that causes the image forming section to follow image formation conditions that do not reflect the content changed by the manual darkness adjustment section.

Abstract: An image forming system which is capable of causing a clear coating apparatus to discharge processed sheets in proper page order, and improving usability and operability of the system by users. An mage forming apparatus is set to perform single-sided image formation or double-sided image formation. A clear coating apparatus is set to perform single-sided clearing coating or double-sided clear coating. Whether to perform inverted discharge of sheets is controlled according to the settings of the image forming apparatus and the clear coating apparatus.

Abstract: In an image forming apparatus, a computing unit computes phase shift amounts A(i) for every correction relative phase angle ?(j) based on an amplitude B of a reference compressional wave ?a, an amplitude C(i) of a detection compressional wave ?(i), and a relative phase angle ?(i). A setting unit specifies the phase shift amounts A(i), and sets a correction relative phase angle ?(j) corresponding to the specified phase shift amounts A(i). A correction unit corrects, based on the correction relative phase angle ?(j) set by the setting unit, a relative phase shift between a periodic variation in the circumferential speed of a first image bearing member and a periodic variation in the circumferential speed of a second group image bearing member by operationally controlling at least one of first and second drive units.

Abstract: An image forming apparatus outputting a color image and a monochrome image obtains data for output image by RIP-convert of accepted image data, and extracts feature of the data for output image. When the data for output image is determined to correspond to a color image, the image forming apparatus outputs a color image corresponding to the data for output image, on condition that the feature satisfies a determination reference.

Abstract: An image forming apparatus includes a rotating member, a driving force transmission unit configured to transmit drive force to the rotating member, a drive unit configured to rotationally drive the rotating member via the driving force transmission unit, a detecting unit configured to detect a velocity of the rotating member and generate velocity data based in the detected velocity, and a control unit configured to control the drive unit based on the velocity data. The control unit calculates a correction value to be added to a drive velocity instruction value so as to cancel velocity variation of velocity data during one rotation of the rotating member, and a correction value is controlled so as to eliminate a difference between a correction drive instruction value obtained by adding a correction value to a drive velocity instruction value and the drive velocity instruction value.

Abstract: A high voltage power controlling apparatus of an image forming apparatus including a DC (direct current) power controller to convert and output a first PWM (pulse width modulation) signal provided from an engine controller into a switching waveform signal, a first voltage transformer to transform the switching waveform signal output from the DC power controller, a rectifier to rectify output power transformed by the first voltage transformer into DC power, first through N(where N is a positive integer greater than one) DC supplies to adjust and output the DC power rectified by the rectifier such that the DC power is adjusted to a predetermined level, first through N AC (alternating current) power controllers to convert and output a second PWM signal provided from the engine controller into switching waveform signals, and second through N+1 voltage transformer to transform the switching waveform signals output from the first through N AC power controllers, to overlap the transformed powers with the DC powers h

Abstract: Generally, an imaging device is capable of applying respective EP engine settings to different zones within a page of media. In an example embodiment, a method includes printing in first and second zones on a page of media using first and second EP engine settings that are respectively associated with the first and second zones. The imaging device prints in the first zone on the page of media based on a first EP engine setting that is associated with the first zone. The imaging device switches from the first zone on the page of media to the second zone on the page of media responsive to a size indicator. The imaging device prints in the second zone on the page of media based on a second EP engine setting that is associated with the second zone.

Abstract: A bypass transporting path apparatus is disposed on a color image recording apparatus and a transporting path connecting apparatus is disposed between a front portion of a monochrome image recording apparatus and a rear portion of the color image recording apparatus. This system includes an operational state monitoring portion that monitors the operational states of the color image recording apparatus and the monochrome image recording apparatus, and a power supply controlling portion that performs control based on the operational states of the color image recording apparatus and the monochrome image recording apparatus to shift any one image recording apparatus to a power saving state and to make the other image recording apparatus wait in a recordable state.

Abstract: An image forming apparatus forms high precision full color image by correcting the adhesion quantity of an image visualizing agent and a position shift of a visible image while performing printing process. The image forming apparatus includes an intermediate transfer unit; plural photoconductors; plural charging units; plural exposure units; plural developing units; plural first transferring units; and plural second transferring units. The intermediate transfer unit has a correction pattern image formed in a region outside a predetermined maximum document region in a direction perpendicular to the moving direction. A detector in the intermediate transfer unit detects the correction pattern image. A correction controller performs correcting, based on detection results of the detector, setting values of one or more of the charging units, the exposure units, and the developing units when a region corresponding to an interval between the visible images passes a position beneath one of the units.

Abstract: A test target is written in a non image zone at set time intervals. The test target is sensed. At least one of frequency, amplitude and phase of banding, which is inherent in a printing device, is determined based on the sensed test target. At least one banding compensation parameter based at least on one of the determined frequency, amplitude and phase of banding is determined. Characteristics of producing an image based on the determined banding compensation parameter are adjusted to compensate the banding inherent in the printing device.

Abstract: A method of changing a color developer in a developer housing of xerographic marking system are disclosed, and may include supplying a chart divided into a plurality of color family sections or quadrants, selecting a new color to be installed in a developer housing corresponding to the color family section, purging old toner from the developer housing until a concentration of old toner is reduced to about 0.1% to 6.0% from its nominal concentration, installing a container of a new color developer in the developer housing, and running the marking system until the required concentration of the new color developer is attained.

Abstract: A dynamic positional shifting, in the process direction, of the images on the second print engine of a tandem machine printing system in order to increase the time (and number of prints) between skipped pitches. Although the photoreceptor belts of each print engine may be out-of-phase, the relative positions of their individual seam zones may be derived during cycle-up. A control procedure then optimizes the position and spacing of each image within each belt revolution of the second engine, while still maintaining the minimum inter-document zone (IDZ) length required for paper path feeding and registration, xerographic process controls, and finishing. Removing the constraints of fixed-dimension IDZ's, as well as being able to adjust spacing and length of individual images on the belt, allows for optimization of system productivity by either delaying or eliminating the need for a skipped pitch.

Abstract: A printing device includes a printing unit which prints an image on a sheet according to a print command, a judgment unit which judges whether a total adhesion amount of a print agent adhering to the sheet for the image printing exceeds a prescribed threshold value based on inputted print data, and a control unit which executes a process for reducing the total adhesion amount of the print agent when the total adhesion amount is judged to exceed the threshold value by the judgment unit.

Abstract: A light emitting device that forms a latent image by irradiating light onto a charged surface of an image carrier. The light emitting device includes an electro-optical substrate that forms an optical image, a focusing lens array that focuses light from the electro-optical substrate to form an erect image of the corresponding optical image on the charged surface, and a frame in which the focusing lens array is fixed. A position determining member, which is formed of resin, is disposed on the frame, comes in contact with a supporting body that supports the image carrier, and determines a distance between the focusing lens array and the image carrier by its own height.

Abstract: A multifunctional machine includes a first component section that starts up taking a first time period, and a second component section that starts up taking a second time period shorter than the first time period. An operation start prediction information obtaining section is provided to obtain operation start prediction information predicting a time when a user starts the multifunctional machine. A start up control section is provided to start up the first component section in advance of the second component section. A power supply control section is provided to supply power from at least one external power source and drive the start up control section in accordance with the operation start prediction information.

Abstract: A method for forming a color image that allows a color image forming device to detect print chromaticity by an actually used print medium and automatically perform an optimal color balance adjustment in consideration of the chromaticity of the print medium. At a first step of the method, it is determined whether a feeder is selected for a subsequent printing operation. If selected, the process proceeds to a second step. If not selected, it is determined that the printing operation is not performed for some time and the process is completed without color balance adjustment. At the second step, a print medium for printing a test pattern is fed from the feeder selected for a subsequent printing operation, which is determined at the first step. A color sensor detects the chromaticity of the test pattern transferred and fused on the print medium, and the color balance is then adjusted.

Abstract: The present invention relates to an image receiver element comprising a single low density layer, wherein the single low density layer comprises non-crosslinked aliphatic polyester containing non-interconnected void space, and wherein the single low density layer does not absorb more than 3 weight % moisture at 80% RH and 21.3° C. as compared to the weight % moisture of said single low density layer at 20% RH and 21.3° C. The invention relates to a method of forming such an image receiver element, a printing system comprising an imaging material and the image receiver element, and a method of printing comprising obtaining an imaging material comprising a colorant layer; obtaining the image receiver element; superposing the colorant layer with the receiver element; and transferring colorant from the imaging material to the image receiver element.

Abstract: A printer configured to adjust gloss appearance of images includes a marking engine configured to render an image on a substrate from input image data; and a controller configured to: (i) correlate a minimum luminance value to be used by the printer based on a gloss selection; (ii) determine a black point compensation function based on the correlated minimum luminance value; and (iii) adjust luminance values for input image data using the determined black point compensation function. A method to adjust gloss appearance of images is also provided.

Abstract: An image forming apparatus capable of preventing toner fusion between recording sheets to thereby offer high usability, with a construction that does not cause increase in cost and size of the apparatus and an undue reduction in productivity. In the image forming apparatus, a toner use amount in a partial region of an toner image transferred from an intermediate transfer belt to a recording sheet is detected. When it is determined that the toner use amount detected for the partial region is equal to or greater than a predetermined amount, a recording sheet conveyance interval is widened.

Abstract: There is provided an image forming apparatus which adopts a distributed control system and suppresses generation of radiation noise without increasing the cost. To accomplish this, the image forming apparatus includes a master control unit that controls the overall image forming apparatus, a plurality of sub-master control units that control a plurality of functions for performing image formation, and a plurality of salve control units that control loads for implementing a plurality of functions. The image forming apparatus performs distributed control. The image forming apparatus determines the operating frequencies of the salve control units in accordance with loads controlled by the salve control units. The image forming apparatus compares the operating frequencies of the slave control units. Based on the comparison result, the image forming apparatus changes the operating frequency of a slave control unit that is equal to the operating frequency of another slave control unit.

Abstract: An image rendering system includes a digital front end to electronically analyze image data to generate geometry dependent image content information. A print engine, operatively connected to the digital front end, renders the image data. A print engine controller, operatively connected to the digital front end and the print engine, controls various parameters of the print engine. The digital front end transmits the image content information to the print engine controller. The print engine controller adjusts a parameter of the print engine based on the transmitted image content information. The transmitted image content information may be coverage information, reload information, and/or toner pile height information. The parameter of the print engine adjusted based upon the transmitted image content information may be fuser temperature and/or process speed of a developer housing and/or flow rate of toner into a developer housing.

Abstract: The present invention provides an image forming apparatus which, when switching operation from color image forming operation to monochromatic image forming operation, forms a monochromatic image on each of a prescribed number of sheets by stopping a part of the functions of yellow, magenta and cyan image forming sections of the color image forming operation, and thereafter, forms a monochromatic image only with a black-only image forming section, thereby permitting extension of service life of the image forming sections, while improving the productivity.

Abstract: An image forming apparatus includes a controller which sets fixing conditions in a fixing unit in accordance with the type of printing medium sensed by a sensor. An intermediate transfer member and sensor are configured as an intermediate transfer member unit. The intermediate transfer member unit is removably installed in the main body of the image forming apparatus. The intermediate transfer member unit has a storage unit which stores information used to determine the type printing medium by the sensor.

Abstract: A printing system includes a plurality of printers, at least a first and a second of the plurality of printers printing in a first print modality. A scheduling system schedules printing of a set of pages by the plurality of printers. The set of pages, when assembled, may include pages where a high level of consistency is desired, such as facing pages or pages which are otherwise to be placed in close relationship. The scheduling system includes at least two scheduling modes, a first mode in which a consistency constraint is applied to the set of pages, and a second mode, different from the first mode, in which the consistency constraint is not applied. The printing system is configured for printing the set of pages in accordance with the first mode and in accordance with the second mode.

Abstract: An image forming apparatus for forming an image with developing toner on an exposed portion has a mode in which a toner image is automatically output onto a recording material without using exposure by an exposure device. When an inclination adjustment of a corona charging device is performed using an output image on the recoding material, the image forming apparatus can output an image for adjusting the inclination of the charging device that is not affected by variation of an exposing light amount of the exposure device.

Abstract: A signal processing apparatus comprising: an optical sensor for outputting a detection signal by detecting a surface of a recording medium on which a correction image is to be formed; and a control section configured to obtain a detection signal of the surface of the recording medium with the correction image from which a dominant frequency component has been deleted by making reverse frequency analysis of an analysis signal that has been obtained by making a frequency analysis of a detection signal outputted by the optical sensor detecting the surface of the recording medium on which the correction image it formed.

Abstract: An image forming apparatus including a receiving part for receiving an image forming request, a conveyor belt for rotating and conveying a recording paper, a charging part for applying charges to the conveyor belt, and an image forming part for forming an image on the recording paper is disclosed. The image forming apparatus includes a cleaning part configured to clean a surface of the conveyor belt by rotating the conveyor belt and setting a contacting member in contact with the surface of the conveyor belt when a bias voltage of the charges is reduced. The cleaning part is configured to clean the surface of conveyor belt when a printing process and a post-printing process are completed by the image forming part and no subsequent image forming request is received by the receiving part.

Abstract: In the case where a sheet on which a transparent toner image is to be formed has low glossiness, when the transparent toner image is formed in a area in which a user wishes to partly lower the glossiness, the glossiness in the area in which the user wishes to lower the glossiness is increased. For that reason, a print as desired by the user cannot be obtained by fixing the transparent toner image in an area corresponding to the area in which the user wishes to lower the glossiness. In the case where the sheet to be subjected to printing is judged as low glossy paper, the transparent toner image is placed in an image formable area except for the area in which the user wishes to lower the glossiness.

Abstract: A print terminal unit includes a storage unit to store a lookup table on which information regarding an image forming apparatus corresponding to at least one type of a document is recorded, a user interface through which at least one type of at least one document to be printed is selected, and a controller to control an image forming apparatus that corresponds to the selected type of the document among the plurality of image forming apparatuses according to the lookup table to print the document. Accordingly, the user easily performs printing operation using an image forming apparatus separately depending on the type of the document.

Abstract: A velocity correction device of an image forming apparatus capable of obtaining a high-quality image. The image forming apparatus includes a rotor, a motor, a motor control unit, and a velocity command memory. The velocity correction device includes a velocity measuring unit, an arithmetic unit, and an interface unit. The velocity correction device is attached to the image forming apparatus. The velocity measuring unit measures the rotational velocity of the rotor when the motor is rotating at a reference rotational velocity which is a fixed velocity. The arithmetic unit compares the measured velocity with a no-velocity-fluctuation velocity of the rotor calculated by the reference rotational velocity of the motor, extracts a velocity fluctuation component of the rotor, and generates the velocity command data to cancel the extracted velocity fluctuation component. The generated velocity command data are transmitted to the velocity command memory through the interface unit, and stored therein.

Abstract: This invention provides an image forming apparatus capable of shortening the user's print waiting time as much as possible when it is determined that image adjustment is necessary during the image forming operation, and a control method therefor. To accomplish this, in a color image forming apparatus including a plurality of image forming stations which form toner images with a plurality of toners on the basis of a job, it is discriminated whether adjustment processing is necessary during a continuous image forming operation based on the job. If it is discriminated that adjustment processing is necessary, it is determined whether each of the image forming stations has a non-operating time enough to execute the discriminated adjustment processing during the image forming operation. The image forming station determined to have a non-operating time enough to execute adjustment processing executes the discriminated adjustment processing during the non-operating time.

Abstract: An image reading apparatus which is capable of preventing images read from a double-sided original from suffering an in-surface color irregularity on each of images read from the respective opposite sides of a double-sided original and a color difference between the front and reverse. A CCD line sensor reads a front-side original image. An image processing ASIC calculates shading correction data for performing shading correction on original image data read from the original image by the CCD line sensor, based on read luminance values obtained by the CCD line sensor by reading a plurality of halftone gradation patches thereon on a correction chart. The shading correction data calculated by the image processing ASIC is corrected based on read luminance values associated, respectively, with at least two of the gradation patches.

Abstract: An image forming device has an imaging unit including: a rotating body; an exposure unit forming an electrostatic latent image on the rotating body; a developing unit developing the latent image using developer to form an image; and a transfer unit transferring the image to a recording medium, a memory storing data on correspondence between first image data, second image data and a first correction amount, the first image data representing a first latent image formed by a first turn of the rotating body, the second image data representing a second latent image formed by a second turn of the rotating body, and the first correction amount used for correcting the second image data so that density of the image on the recording medium closer to density of the second latent image; a correction amount determining unit determining the first correction amount corresponding to the first and second image data based on the data stored in the memory; and a correcting unit correcting the second image data based on the firs

Abstract: An image forming apparatus includes: a cartridge attachment portion; an image forming unit; a reading unit; and a control unit. A toner cartridge configured to accommodate toner is removably attached to the cartridge attachment portion. The toner cartridge includes a cartridge mechanism unit mechanically driven and a storage medium for storing torque information including information indicating torque used for a mechanical drive of the cartridge mechanism unit. The image forming unit is configured to print an image on a surface of a printing medium using toner accommodated in the toner cartridge. The reading unit is configured to read the torque information from the toner cartridge attached to the cartridge attachment portion. The control unit is configured to determine a number of printing media to be printed by the image forming unit per unit time, according to the torque information read by the reading unit.

Abstract: A printer is operable for image formation onto a sheet of a sheet width Lp, with a sheet spacing Lg and a printing transfer speed Vg, a constant speed transferrer makes sheet transfer at the printing transfer speed Vg from a register via the printer to a speed change position, a variable speed transferrer makes sheet transfer from the speed change position to the register, and a transfer controller controls sheet transfer speeds, the variable speed transferrer having sections for sheet transfer, including deceleration and acceleration sections for sheet reversal at the sheet reversing path, and a constant speed section for transfer at a constant transfer speed Vr, the transfer controller determining a circulating sheet number N, executing a calculation of transfer speed Vr employing sheet width Lp, sheet spacing Lg, printing transfer speed Vg, and accelerations, to enable sheet transfer for circulation within a time interval of N×(Lp+Lg)/Vg.

Abstract: An image forming apparatus is capable of reducing the vast amounts of image forming apparatus input lines by placing detection data from a plurality of detectors on a single signal line. An image forming apparatus may include an image forming controller configured to control a movement of the image forming apparatus, plural drivers configured to drive plural actuators, an identification controller configured to be coupled to a data signal line, an identification signal line and a term signal line, wherein the identification controller is configured to identify one of the plural drivers based on a term signal and an identification signal that are output from the image forming controller, and to output a driving signal from the image forming controller to the identified driver.

Abstract: It is an object of the present invention to provide a paper discharge device that can sort sheets on a tray. The paper discharge device has paper discharge rollers, a tray and a driving mechanism. The paper discharge rollers are configured to discharge a sheet having an image formed thereon. The tray is configured to be stacked with the sheet discharged from the paper discharge rollers. The driving mechanism is configured to move the tray in a direction approaching the paper discharge rollers and a direction away from the paper discharge rollers and vary a stacking position of the sheet on the tray.

Abstract: A digital image processing method. The method includes printing a first set of reference marks on one side of a substrate with a first print engine; printing a second set of reference marks on the same side of the substrate as the first set of reference marks with a second print engine; sensing both sets of reference marks on the substrate with an image sensing unit and generating a digital image of the reference marks; performing image analysis on the digital image to obtain an image-to-image distortion map where the image-to-image distortion map is a local measure of difference between the first set of reference marks and the second set of reference marks; and generating a compensated customer image by using the image-to-image distortion map to reduce registration errors when using the first and second print engines.

Abstract: An image forming apparatus is provided which is capable of forming higher-quality images by detecting a toner concentration with higher accuracy to attain appropriate toner supply and image density. A value obtained by adding a correction value based on a temperature, humidity, a print coverage, or the like to a developer concentration adjustment value is set as a control voltage value Vc which is to be inputted to a toner concentration sensor, and an output value of the toner concentration sensor is detected for each of process speeds. A difference between the output value detected and a value at reference process speed is calculated and based on the difference, a correction value is further calculated. Such another calculation of the correction value with use of the output value detected allows for highly accurate correction.

Abstract: An image forming apparatus includes a processing unit which performs an image recording process for recording an image on a recording medium based on image data; a movement mechanism which moves the processing unit; a first control section which controls the image recording process performed by the processing unit; and a second control section which acquires a state of progress of the image recording process and controls the movement mechanism so as to move the processing unit to a position according to the progress state.

Abstract: A double-side recording apparatus which inverts a recording medium after the end of the recording of a first face, and then performs the recording of a second face, includes: a recording unit which performs recording on the recording medium; a transportation unit which transports the recording medium to a position where the recording unit can perform the recording; a movement unit which moves a movable member capable of engaging with the recording unit to an engagement position and a non-engagement position; an inversion unit which inverts the recording medium sent from the transportation unit and returns the inverted recording medium to the transportation unit; a power source which is common to the transportation unit, the movement unit, and the inversion unit;

Abstract: A belt driving control device includes an endless belt looped over a plurality of supporting rollers, a driving source supplying rotational driving force the supporting rollers, a detecting section detecting a periodical thickness deviation of the endless belt in a circumferential direction of the endless belt and carrying out data sampling for detection of the thickness deviation simultaneously with rotation of the endless belt, a memory storing data on the thickness deviation obtained based on the data sampling, and a control section controlling drive of the driving source such that the detected thickness deviation of the endless belt is canceled out based on the data on the thickness deviation stored in the memory, and such that the endless belt is driven to travel one rotation upon detecting a predetermined condition to carry out the data sampling for one rotation and update the stored data with new data.