Abstract: A tandem color laser printer 1 is provided with a photosensitive drum unit 15, a developing unit 14, and a scanning unit 13 for each color. The developing units 14, each including a main developer unit 25 and a toner hopper 24, and the scanning units 13, which irradiate laser beam, are alternately stacked vertically to overlap with each other in the vertical direction. This arrangement eliminates space required when arranging the developing units 14 and scanning units 13 side by side, thereby reducing the footprint of the color laser printer 1.

Abstract: To provide a digital printing system that can satisfactorily reproduce yellow, magenta, and cyan colors, respectively, and can excellently reproduce specific skin tones and have significantly improved sensory image quality, a digital printing system reproduces a yellow (Y) color having a* and b* values of −15 to 0 and +71 to +85, respectively, in the CIE 1976 (L*a*b*) color space at a blue density of 1.0; a magenta (M) color having a* and b* values of +50 to +65 and −30 to 0, respectively, at a green density of 1.0; and a cyan (C) color having a* and b* values of −45 to −15 and −40 to −5, respectively, at a red density of 1.0 and produces a print having L*, a*, and b* values of +58 to +78, +20 to +30, and +25 to +32, respectively, from digital image data with RGB values of 239, 167, and 127, respectively.

Abstract: A multicolor image forming apparatus comprises a first image forming unit, and a second image forming unit, having respectively an image forming member, an intermediate transfer member, and a secondary transfer section for transferring the toner image from the intermediate transfer member onto a recording material, wherein there are provided a priority mode setting section for setting a multicolor priority mode or a monochrome priority mode, and a controller to control in such a way that in an idling condition and in a waiting condition, when the multicolor priority mode is set, all of the image forming members are in press-contact with the intermediate transfer member, and when the monochrome priority mode is set, only the image forming member of the first image forming unit is in press-contact with the intermediate transfer member.

Abstract: An apparatus and method for applying dot-gain (110) compensation to halftone bitmap files used in printing a digital halftone image. Dot-gain is added by thresholding (250) the output of a convolution of the original bitmap image with a spatial filter (200). Averaging (220) is performed to specify the level of the threshold to be applied. The level of dot-gain applied is a function of the threshold level.

Abstract: An optical system for an image forming apparatus which a first light source for selectably emitting a plurality of image forming light beams based upon control signals and a second light source for emitting image forming light beams of a number of less than that of said first light source. The first light source of the optical system selectably emitting multiple light beams and a single beam, e.g. selectably emits two beams and a single beam.

Abstract: A public presentation system is presented comprising a display system that can be remotely changed, so that multiple different images are successively displayed with minimal interruption. The system utilizes ionography techniques for non-contact printing and imaging for display. Thus by exploiting electrostatic imaging techniques, an advertisement can be displayed promptly by transferring a toner image onto an imaging belt.

Abstract: A color image forming apparatus includes a controlling unit for controlling an exposure unit, developing devices, etc., so that an ordinary image of one color is formed within a period of time in which a carrier rotates once, and density detection pattern images of a plurality of colors are formed within the period of time in which the carrier rotates once.

Abstract: Image carriers are arranged so as to satisfy an expression; −Ts/2<t1+t2−t3−nTp<Ts/2. “Ts” is a time period of scanning performed by each of scanning surfaces of a rotary polygon mirror. “Tp” is a time period of one rotation of the polygon mirror. “t1” is a time period required for a first image formed on a first image carrier among the image carriers is transferred to the transferred object at a first transferring position. “t2” is a time period required for the first image is traveled from the first transferring position to a second transferring position at which a second image formed on a second image carrier adjacent to the first image carrier at a downstream of the transporting path is transferred to the transferred object. “t3” is a time period required for the second image formed on the second image carrier is transferred to the transferred object at the second transferring position.

Abstract: An image forming apparatus is provided with photosensitive drums for forming latent images by irradiation of light reflected by a polygon mirror and a fixing device for fixing toner images corresponding to the latent images on a sheet material. Deterioration of an image to be formed is prevented if reflective surfaces of a reflective polyhedron are thinned out in reducing a process speed of image formation. This apparatus is further provided with a control unit for, if the number of surfaces of the polygon mirror is m (where m is an integer of three or more), performing a control for selecting n such that m/(n+1) is not an integer as a relation between m and n and performing a control for making n surfaces unused as a reflective surface of light among continuous n+1 surfaces of the reflective polyhedron in decelerating the image forming process.

Abstract: An improved electrocoagulation printing method is disclosed. A plurality of dots of colored, coagulated colloid representative of a desired image are formed on a moving, olefin-coated surface of a positive electrode, by electrocoagulation of a colloid present in an electrocoagulation printing ink filling an electrode gap defined between a positive electrode and a plurality of negative electrodes. The improvement comprises applying to selected negative electrodes a trigger signal of a voltage sufficient to energize same and cause point-by-point selective coagulation and adherence of the colloid onto the positive electrode surface opposite the surfaces of the energized electrodes.

Abstract: An image forming method wherein a surface of a photoconductor having a photoconductive layer provided on a conductive support is scanned at least along a main scanning direction of the photoconductor with a writing light beam having a wavelength of &lgr; &mgr;m and a spot diameter &phgr; &mgr;m to form an electrostatic latent image thereon. The surface of the photoconductor has such a roughness that the sectional curve thereof along the main scanning direction is represented by a function y=f(x) when the main scanning direction and the direction of the vertical height are assumed to be the X-axis and the Y-axis, respectively. The maximum height of the sectional curve in a region from an arbitral position x on the X-axis to a position (x+&phgr;) on the X-axis is at least &lgr;/2n &mgr;m where n is a refractive index of the photoconductive layer at the wavelength of the light beam.

Abstract: A method and an apparatus for adjusting devices (1, 1′) for generating color separations (2, 2′) in a multicolor printing machine (3), changes in the dimensions (4, 4′, 5, 5′) of printing substrates (6) being taken into account by controlling the image generation. Changes in the dimensions (4, 4′, 5, 5′) of printing substrates (6) during or after printing are to be taken into account as early as during the image generation. The fiber orientation (7) of printing substrates (6) is registered and, on the basis of the fiber orientation (7) and values from experience (8, 8′, 10, 10′, 10″) of the behavior of printing substrates (6) depending on the fiber orientation (7), control being carried out before the start of printing.

Abstract: An image forming apparatus comprises: a plurality of image forming means 7 arranged along a line, which include image carriers and developing means for developing latent images formed on the image carriers, respectively; and an exposure means 6 which emits laser beams for exposure to form latent images on the respective image carriers, wherein the exposure means 6 comprises a plurality of laser beam sources to be modulated according to image data corresponding to the image carriers 17, a common polygon mirror 21 which is arranged horizontally or vertically and in which laser beams from the laser beam sources are reflected at a common reflection facet of the polygon mirror 21 and are thus deflected, and optical paths for deflecting the laser beams in non-parallel with each other toward the respective image carriers 17.

Abstract: An intermediate belt made of an endless belt is provided by 45 degrees inclined horizontally and looped over two rollers at both its ends, and four photosensitive drums are provided in contact with the top surface of this intermediate belt. A reflection mirror is provided over each photosensitive drum, and a single polygon mirror is provided on almost the same level as these reflection mirrors. The polygon mirror is provided on the side of the reflection mirror of which optical path to the corresponding photosensitive drum is the longest so that the optical path lengths from the polygon mirror to the respective photosensitive drums are equal to each other.

Abstract: A color image forming apparatus for forming a color image on a storage medium using a laser beam generated from a laser generating means includes a plurality of image data interfaces provided between the color image forming apparatus and a peripheral device, image data interface conversion means for converting each of the image data interfaces into an image data interface for the laser generating means, and a single control means for controlling a drive timing of the laser generating means, the control means controlling the drive timing of the laser generating means for each one of a plurality of colors based on image data input from the image interface conversion means.

Abstract: A system and method are provided for generating a color plane in an image. For example, a noise generation device is coupled to at least one component within a laser imaging assembly to cause a random deviation in the placement of the spots within respective color planes. This random deviation advantageously alleviates the problem of misregistration, white gapping, and moiré patterns, etc. In one embodiment, a system is provided that includes a laser imaging assembly having a laser generating a laser beam that is optically coupled to a photoconductor, typically an organic photoconductive (OPC) drum. The laser beam is optically coupled to a number of predetermined positions on the OPC drum to generate an image on the OPC drum. A noise generator is operatively coupled, for example, to a component in the laser imaging assembly.

Abstract: A driving means 6 is placed below a photoconductor drum 2. The driving means 6 includes first to fourth developing rollers 13A-13D and toner storage chambers 11A-11D. The developing means 6 can be shifted by a developing-device moving motor 9 to bring one of the developing rollers 13A-13D which corresponds to one of liquid toners 12A-12D to be developed in close to the photoconductor drum 2, followed by developing a latent image formed by an exposure. At this time, the distance between one of the developing rollers 13A-13D and the photoconductor drum 2 can be appropriately adjusted. In addition, before the development, meniscus of the liquid toner is quickly formed between the developing rollers 13A-13D and the photoconductor drum 2 by rotating the development rollers 13A-13 at the rotation speed higher than the rotation speed thereof at the development.

Abstract: In an electrophotographic apparatus, regions having at least three different potential levels Vc, Vw, and Vr are formed on a photosensitive member by using an exposing device, and developing processes respectively using colored particles of different kinds are performed by normal development and reversal development on two potential levels Vc and Vr excluding the intermediate potential level Vw. The apparatus has an auxiliary exposing unit for forming a fringe development preventing potential in an edge of an image forming region in order to prevent fringe development from occurring. The auxiliary exposing unit sets an auxiliary exposure amount by performing pulse-width modulation on a laser driver.

Abstract: In a process and apparatus for decorating an article, printing ink or electrostatic charges is or are applied in dependence on a digital program in dot form to the article carried by a holder, with individual dots going together to at least form a partial pattern or image. In the case of the latent pattern formed by electrostatic charges, it is then brought into contact with ink particles to form the decoration. In both cases the article is transported along a transportation path through at least one print station provided with an inkjet print head or an ionographic print head, the print head being controllable in dependence on the digital program. The individual nozzles or the electrodes of the respective print head are actuated in accordance with the digital program which is called up for example in dependence on the transportation movement of the article.

Abstract: An optical system for an image forming apparatus which a first light source for selectably emitting a plurality of image forming light beams based upon control signals and a second light source for emitting image forming light beams of a number of less than that of said first light source. The first light source of the optical system selectably emitting multiple light beams and a single beam, e.g. selectably emits two beams and a single beam.

Abstract: A color electrophotographic apparatus having a photosensitive member, an exposing device for forming an electrostatic latent image on the photosensitive member, four developing devices which attach toner on the photosensitive member and form a toner image and a transfer member for transferring the toner image onto a printing medium. The four developing devices include respectively a developing device for a yellow image, a magenta image, cyan image, and a black image. Each developing device includes a toner storing chamber for storing toner of a nonmagnetic one-component developer, a toner carrying member for forming a toner layer of the toner, a regulating member for regulating an amount of toner attached to the toner carrying member, a toner recovery chamber having an agitating member for agitating recovered toner, and a separating member for separating a toner supply chamber for the toner carrying member from the toner recovery chamber.

Abstract: An image forming system having multiple photoconductors arranged in a line and forming one body as one unit, multiple development devices and multiple exposure devices arranged on one side of the line of the multiple photoconductors, an intermediate transfer device arranged on the other side of the line of the multiple photoconductors and a form cassette arranged below the line of the multiple photoconductors. The image forming system further includes a transfer device and a fusing device arranged at an opposite side of the intermediate transfer device with respect to the line of the multiple photoconductors.

Abstract: A system and method for making a personalized wallpaper border product, includes means for providing at least one personal digital image; a work station for receiving the at least one personal digital image and arranging the at least one personal digital image in a pattern suitable for printing on a wallpaper border strip; and an inkjet printer for printing the pattern on the strip.

Abstract: An image forming apparatus maintains a constant beam scanning state so that, light beams scan each drum always in the same state once a desired color overlapping accuracy is obtained by controlling color registration in color image formation. This mechanism achieves constantly fine color overlapping without forming a test pattern several times or consuming toner unnecessarily. A beam passage switch is provided in a laser scanning system. Sensors provided near each photosensitive drum determine whether each light beam has scanned a certain portion with no inclination or a certain scanning area, or whether each image magnification provides a desired size.

Abstract: An image processing apparatus capable of color image formation with a plurality of color components, which solves a problem of increment of processing time in monochrome image formation due to correction on image formation conditions with predetermined patch formation. For this purpose, in case of monochrome image formation, even if a tonality control request flag is set, an image formation sequence is started without performing tonality control. Thus processing time can be reduced in monochrome image formation.

Abstract: An optical scanning device for scanning plural surfaces including a plurality of laser light units each configured to emit a laser beam, a deflecting device configured to deflect the laser beams from the plurality laser light units to sweep a plurality of predetermined planes, respectively, and a scanning image forming optical unit configured to project the laser beams deflected by the deflecting device on the plural surfaces, respectively, to scan the plural surfaces with the laser beams. The scanning image forming optical unit includes a plurality of optical detecting devices configured to detect the laser beams and a first plurality of reflecting devices positioned to reflect at least two laser beams of the laser beams toward one of the plurality of optical detecting devices.

Abstract: A driving means 6 is placed below a photoconductor drum 2. The driving means 6 includes first to fourth developing rollers 13A-13D and toner storage chambers 11A-11D. The developing means 6 can be shifted by a developing-device moving motor 9 to bring one of the developing rollers 13A-13D which corresponds to one of liquid toners 12A-12D to be developed in close to the photoconductor drum 2, followed by developing a latent image formed by an exposure. At this time, the distance between one of the developing rollers 13A-13D and the photoconductor drum 2 can be appropriately adjusted. In addition, before the development, meniscus of the liquid toner is quickly formed between the developing rollers 13A-13D and the photoconductor drum 2 by rotating the development rollers 13A-13 at the rotation speed higher than the rotation speed thereof at the development.

Abstract: An image forming apparatus maintains a constant beam scanning state so that light beams scan each drum always in the same state once a desired color overlapping accuracy is obtained by controlling color registration in color image formation. This mechanism achieves constantly fine color overlapping without forming a test pattern several times or consuming toner unnecessarily. A beam passage switch is provided in a laser scanning system. Sensors provided near each photosensitive drum determine whether each light beam has scanned a certain portion with no inclination or a certain scanning area, or whether each image magnification provides a desired size.

Abstract: A transparent image producing display or receiver which uses a suspension fluid for producing pixels of an image includes at least one image-forming layer having a structure which defines a plurality of pixels, with the structure receiving a suspension fluid having field-driven particles, which move in response to an externally applied field, where, in a first condition, the field-driven particles produce a first level of transmitted incident light and, in an second condition, produce a second level of transmitted incident light.

Abstract: An image forming apparatus maintains a constant beam scanning state so that light beams scan each drum always in the same state once a desired color overlapping accuracy is obtained by controlling color registration in color image formation. This mechanism achieves constantly fine color overlapping without forming a test pattern several times or consuming toner unnecessarily. A beam passage switch is provided in a laser scanning system. Sensors provided near each photosensitive drum determine whether each light beam has scanned a certain portion with no inclination or a certain scanning area, or whether each image magnification provides a desired size.

Abstract: An intermediate belt made of an endless belt is provided by 45 degrees inclined horizontally and looped over two rollers at both its ends, and four photosensitive drums are provided in contact with the top surface of this intermediate belt. A reflection mirror is provided over each photosensitive drum, and a single polygon mirror is provided on almost the same level as these reflection mirrors. The polygon mirror is provided on the side of the reflection mirror of which optical path to the corresponding photosensitive drum is the longest so that the optical path lengths from the polygon mirror to the respective photosensitive drums are equal to each other.

Abstract: A multicolor image forming apparatus comprises a first image forming unit, and a second image forming unit, having respectively an image forming member, an intermediate transfer member, and a secondary transfer section for transferring the toner image from the intermediate transfer member onto a recording material, wherein there are provided a priority mode setting section for setting a multicolor priority mode or a monochrome priority mode, and a controller to control in such a way that in an idling condition and in a waiting condition, when the multicolor priority mode is set, all of the image forming members are in press-contact with the intermediate transfer member, and when the monochrome priority mode is set, only the image forming member of the first image forming unit is in press-contact with the intermediate transfer member.

Abstract: In order to provide an image forming system characterized by compact configuration, high speed printing, high picture quality recording and excellent maintainability without image misregistration, an image forming system is provided, wherein multiple photoconductors are arranged along one of the surfaces of the intermediate transfer belt which is elongated in the longitudinal direction, and a fusing device is located on the other surface, with the photoconductors being integrated in one unit.

Abstract: A method for suppressing phantom images in a digital copying or printing process wherein toner material in the form of pixels of image information (D (x,y), in which D is the image density for point x,y, is transferred through a sequence of process steps from a photoconductive surface to an image-recording medium, where at least one process step is influenced in a predetermined manner by at least one preceding process step for the same surface point x,y, which comprises connecting the image information for each pixel of image information to be printed on the basis of image information D(x,y-&Dgr;y1) for at least the pixel associated with the same surface point x,y, and said preceding process step, thereby compensating for the influence of said preceding process step.

Abstract: The color image forming apparatus comprises a transfer belt device which feeds a transfer member such as a paper and a plurality of image forming units. The image forming units are disposed facing towards the transfer belt device. The transfer belt device, at least in a portion in which the image forming units have been disposed, is arranged such that it is inclined with respect to the ground. Each of the image forming unit forms a desired image and sequentially transfers the formed image on the transfer member fed by the transfer belt device.

Abstract: The invention provides an optical scanning device for color image formation in which color aberration depending on the variation in the image formation position on the scanned surface caused by the angle change of the optical system.

Abstract: A sharp image having excellent color balance is formed by preventing differences in the amount of light among recording heads. When forming an image using at least two recording heads, each having transfer thyristors and light-emitting thyristors arranged in the form of an array, by causing the transfer thyristors of M, C and Y recording heads having light-emitting thyristors not to be lit to perform transfer operations as the transfer thyristors of a K recording head having light-emitting thrystors to be lit, the difference in the amount of light among the recording heads is corrected.

Abstract: An image processing apparatus capable of color image formation with a plurality of color components, which solves a problem of increment of processing time in monochrome image formation due to correction on image formation conditions with predetermined patch formation. For this purpose, in case of monochrome image formation, even if a tonality control request flag is set, an image formation sequence is started without performing tonality control. Thus processing time can be reduced in monochrome image formation.

Abstract: A printer has monochrome and color printing heads for printing color and monochrome images, respectively, and a media feed path for moving sheets of media by the printing heads. The media feed path has a color position in which the color printing heads print color images and the monochrome printing head prints monochrome images, and a monochrome position in which the monochrome printing head prints monochrome images but the color printing heads cannot print color images. A memory stores data on prior print jobs, and a control circuit switches the media feed path from the color position to the monochrome position in response to the data stored in the memory.

Abstract: Toner/ink is saved while still being able to print any given color value within the full color gamut of a given printer. Combinations of varying percentages of a printer's toners/inks (cyan, magenta, yellow and black) are determined for maximum black substitution with varying percentages of under color addition (UCA) (e.g., 0%, 50%, 80%, and 100%). Patches of varying combinations of CMYK using maximum black substitution and a given percentage of UCA are printed out, and the color value (L*a*b*) of each patch is measured. Tables are generated having the percentage amounts of C,M,Y, and K and the corresponding measured color value. A first table represents maximum black substitution with 0% UCA. If a desired color value falls within this table, the corresponding CMYK combination represents the most toner/ink that can be saved. If a desired color value does not fall within the first table, subsequent tables representing increasing percentage amounts of UCA are examined.

Abstract: In an electrophotographic apparatus, regions having at least three different potential levels Vc, Vw, and Vr are formed on a photosensitive member by using an exposing device, and developing processes respectively using colored particles of different kinds are performed by normal development and reversal development on two potential levels Vc and Vr excluding the intermediate potential level Vw. The apparatus has an auxiliary exposing unit for forming a fringe development preventing potential in an edge of an image forming region in order to prevent fringe development from occurring. The auxiliary exposing unit sets an auxiliary exposure amount by performing pulse-width modulation on a laser driver.

Abstract: A vacuum fluorescent printer including a print head (60) having luminous blocks (32, 33, 34) each having a plurality of luminous elements arranged in a main scanning direction for irradiating a photosensitive material with light released from phosphorous objects to which electrons are applied based on a drive signal, thereby forming dots on the photosensitive material. A further luminous block (32b) is provided which is spaced from the luminous blocks (32a, 33, 34) in the sub-scanning direction and used for printing a particular color among the three colors (R, G, B). Each dot of the particular color is formed by light from a plurality of luminous blocks (32a, 32b). A printer controller (7c) is provided for generating a pulsed drive signal as the drive signal. The number of pulses in the drive signal is determined based on a density value of the image data, and the slower a moving speed is in the sub-scanning direction, to the larger pulse width the drive signal is set.

Abstract: When a multiple-color image is printed by electrophotography unwanted spaces are produces between different colors. These spaces are attributed to non-development of toner caused by the influence of an electric field at the boundary of an electrostatic latent image formed on a photosensitive drum. Accordingly, when data conversion is converted from two-bit data of a bitmap to eight-bit data that are used for modulating a light signal, a pixel of interest and the neighboring 9×9 pixels are stored and the state thereof is determined. If the pixel of interest is a white pixel and the neighboring pixels are all non-white pixels, then the pixel of interest is not left at a value corresponding to white, but is converted to a value corresponding to a potential that will not develop toner. The photosensitive drum is irradiated with a laser based upon the data resulting from the conversion.

Abstract: A method and apparatus for an electrophotographic color printer. The method of developing a color image onto a photoconductor includes providing a single base charge to the photoconductor and then using a cascade of developer potentials for the toners in the process such that earlier applied toners are at higher electrical potentials than are later applied toners. Consequently, the latter applied toners will not tend to migrate to the previously developed sections. Additionally, the method includes applying color toners in the sequential order of black, cyan, magenta (or magenta, cyan), and yellow. In this manner, any contamination of previously applied toner by later applied toner will be less evident. An apparatus for performing this cascading color printing method is also disclosed. The invention further includes an apparatus for performing four-beam laser scanning of a photoconductor using a single rotatable, polygonal-sided mirror and as few as one laser.

Abstract: An electrophotographic imaging apparatus includes a plurality of photoconductive drums and a plurality of printhead assemblies. Each drum has an axis of rotation and a photoconductive peripheral surface. A plurality of the axes of rotation of the drums lie in a generally common plane. The peripheral surface of each drum rotates in a common direction defining an advance direction of the print medium. Adjacent drums are disposed at a first distance away from each other between the axes of rotation. Each printhead assembly is associated with a respective drum and is configured for generating a laser beam which impinges upon the respective drum along a line of incidence. The printhead assemblies are disposed at a second distance from one to another which is greater than the first distance.

Abstract: Developing devices are provided adjacent to a light sensitive element. An intermediate transfer drum is provided adjacent to the light sensitive elements. After exposure of the light sensitive element, a first color or third color image is formed on the light sensitive element. On the other hand, after exposure of the light sensitive element, a second color or fourth color image can be formed on the light sensitive element. The first color image is transferred from the transfer unit to the intermediate transfer drum at the first transfer portion, and the second color image is transferred from the transfer unit at the second transfer portion so as to be superimposed on the first color image. Similarly, the third color image is transferred so as to be superimposed on the second image and the fourth color image is transferred so as to be superimposed on the third color image to the intermediate transfer drum. Accordingly, the first to fourth color images are superimposed.

Abstract: An image forming apparatus has a processing part which forms a color image from an input image by overlapping areas of different colors with each other such that the different colors have different sizes based on a conspicuous color order caused by color displacement.

Abstract: A vacuum fluorescent printer including a print head (60) having luminous blocks (32, 33, 34) each having a plurality of luminous elements arranged in a main scanning direction for irradiating a photosensitive material with light released from phosphorous objects to which electrons are applied based on a drive signal, thereby forming dots on the photosensitive material. A further luminous block (32b) is provided which is spaced from the luminous blocks (32a, 33, 34) in the sub-scanning direction and used for printing a particular color among the three colors (R, G, B) Each dot of the particular color is formed by light from a plurality of luminous blocks (32a, 32b). A printer controller (7c) is provided for generating a pulsed drive signal as the drive signal. The number of pulses in the drive signal is determined based on a density value of the image data, and the slower a moving speed is in the sub-scanning direction, to the larger pulse width the drive signal is set.

Abstract: A printer head capable of increasing intensity of dot-like light irradiated onto a record medium without requiring to increase a drive voltage or the number of printer heads arranged. The optical printer head includes a luminous element including two luminous dot arrays arranged in parallel to each other at a predetermined interval in a sub-scanning direction. The luminous dot arrays each are constituted of a plurality of luminous dots which have a dimension in the sub-scanning direction increased by a predetermined magnification as compared with that in a main scanning direction and are spaced from each other at identical intervals in the main scanning direction. The luminous dots of the two luminous dot arrays are arranged in an offset manner while being deviated from each other in the main scanning direction by a distance equal to the dimension thereof in the main scanning direction.

Abstract: An apparatus and method for calibrating a multi-color imaging system are provided. The multi-color imaging system is capable of applying different colorants to a substrate based on a plurality of input color values. The input color values control amounts of the colorants to be applied to the substrate by the imaging system. A subset of the input color values is selected and used to control the imaging system to apply one or more of the different colorants to the substrate, thereby forming a plurality of different color patches on the substrate. The subset of input color values is selected such that one of more of the different color patches is formed by application of a combination of at least two of the different colorants to the substrate. Color values are measured for each of the different color patches, and compared to reference color values, representing a calibrated condition of the imaging system. An error value is calculated.