JP2006035645A - Image output system, controller, method of outputting image, program for allowing computer to execute the method, and recording medium storing the program in computer-readable manner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image output system capable of effectively performing correction of a color output characteristic corresponding to a kind of recording paper. <P>SOLUTION: This color laser printer 200 comprises a correction information memory section 130 wherein correction coefficient information 131 correlating a gradation characteristic with respect to an intermediate transfer belt 6 of the color laser printer 200 with a gradation characteristic with respect to each recording paper accommodated in the color laser printer 200 is stored beforehand, an image output section 220 for forming a correction image (a color patch image) on the intermediate transfer belt 6, a density sensor 28 for measuring a density value of the correction image, and a correction section 112 for determining a correction value of the gradation characteristic with respect to a designated recording paper P based on the measured result of the density value and the correction coefficient information 131 about the recording paper P. The color laser printer 200 outputs a printing image on the recording paper P according to image data using the correction value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image output system, a control device, an image output method, a program that causes a computer to execute the image output method, and a storage medium that stores the program in a computer-readable manner. The present invention relates to a technique for suitably outputting an image by an outputable image output apparatus. In particular, the present invention relates to control for effectively performing image output processing when an electrophotographic color laser printer is applied as the image output apparatus.

  In recent years, due to the spread of DTP (Desk Top Publishing) and the like, the work process in which an image ordered by a print orderer is scanned on a computer with a scanner and is used for page imposition has become common. Digital editing is becoming uncommon.

  In such a printing plate making process, in order to achieve further efficiency, image setter output for directly outputting the image data with the page imposition to the film, or CTP (Computer to Plate) for directly recording the image on the printing plate. ) Output, and CTC (Computer to Cylinder) output for directly recording an image on a printing plate wound on a cylinder of a printing press.

  At this time, performing film output or printing plate output for calibration has a problem that waste is generated in the film or printing plate and extra work increases. Therefore, there has been a demand for DDCP (Direct Digital Color Proof), that is, a system that directly outputs a color image for calibration from image data.

  According to this DDCP system, for example, before the page imposition image data is recorded on a plate-making film by an image setter or the like, a printing plate is created directly by a plate setter (a machine that outputs a printing plate in a CTP output system). The DCP (Digital Color Proof) that reproduces the target image can be created before starting the printing work or before recording the image directly on the printing plate wound on the cylinder of the printing machine by CTC. The person can calibrate the pattern, color tone, etc. of the image with reference to this DCP.

  Recently, attention has been paid to the movement of applying a multifunctional machine (hereinafter collectively referred to as a color laser printer) having functions such as an electrophotographic color laser printer, a scanner, a copier, and a facsimile to a DDCP system. Conventionally, color laser printers have been used for comps to understand the finished image, but with the recent improvement in image quality of color laser printers, they have also been applied to the output of proof images. It is coming. Reflecting the fact that high-quality color images can be output at low cost and at high speed, they have come to be used for producing final printed matter in small lot printing and the like. Against this backdrop, there is a growing demand for a single color laser printer to cover both small lot printing and DCP output.

  Incidentally, since an electrophotographic color laser printer is easily affected by changes in environmental conditions such as temperature and humidity, and aging such as component life, various corrections are required for its use. In particular, in order to improve the color reproducibility of the output image, correction of intermediate colors (gradation correction) is important. For example, a correction image is formed before the actual image output. There is a method of performing correction based on the image.

  Patent Document 1 discloses an example of such correction processing. The control device (image processing device) described in the document forms dots by forming dots in a predetermined area in a pixel, and expresses a gradation by a halftone dot composed of a plurality of dots. A halftone processing unit that generates image formation information corresponding to the dot area in the pixel according to the gradation data with reference to a conversion table that is supplied and has a correspondence between gradation data and image formation information for each pixel, and a test A conversion table correction unit which is supplied with the print result and changes and sets the conversion table according to the test print result. Accordingly, by changing the conversion table according to the result of the test printing, correction for the change in the gamma value of the electrophotographic color laser printer is performed.

  However, since an image output device such as an electrophotographic color laser printer generally uses a plurality of types of recording paper (output paper), in order to improve color reproducibility. Depending on the type of recording paper, it is necessary to perform correction processing for color output characteristics such as gradation characteristics.

  The configuration described in Patent Document 2 has been devised in such a background. In an image forming apparatus that performs image density control by feedback control using one or more parameters as an operation amount, a reference for density control is provided on an image carrier. Control reference patch creating means for creating a patch, patch density measuring means on the image carrier for measuring the patch density on the image carrier, and calibration reference for creating a calibration reference patch on output paper (recording paper) Patch creation means, patch density measurement means on output paper for measuring patch density on output paper, patch density measurement value of patch on image carrier formed when creating calibration reference patch on output paper, and output paper Based on the measured patch density value, calibrate the target density of the density control reference patch used for feedback control, and set the calibrated target value as the calibration target value. And image density control by executing feedback control using parameters as manipulated variables so that the density of the density control reference patch matches the calibration target value set by the target value calibration means. It has a configuration.

  However, in the configuration of this document, every time the type of recording paper used changes, both image (patch) output to the image carrier (intermediate image forming medium) and image output to the recording paper are performed and the density is measured. Therefore, there is a problem that it takes time and labor to execute the correction process.

JP 2000-333012 A (Claim 1) JP-A-11-148978 (Claim 1)

  The present invention has been made in view of such circumstances, and an image output system, a control device, and an image output method capable of easily and effectively correcting color output characteristics in accordance with the type of recording paper. An object of the present invention is to provide a program for causing a computer to execute the image output method, and a storage medium storing the program in a computer-readable manner.

  In order to achieve the above object, the invention according to claim 1 is directed to an image output device that outputs a print image based on image data onto a designated recording sheet from among a plurality of types of recording sheets, and the image output. An image output system including a control device that transmits the image data to an apparatus, wherein color output characteristics of the image output device for an intermediate image forming medium and colors for each of the plurality of types of recording paper Storage means for storing related information for associating output characteristics, correction image forming means for forming a predetermined correction image on the intermediate image forming medium, and the color output characteristics of the formed correction image. Based on the measurement means for measuring, the stored related information about the specified recording sheet, and the measured color output characteristics, the specified recording Correction means for correcting the color output characteristics with respect to the image, and the image output device uses the corrected color output characteristics to place the print image based on the image data on the designated recording paper. It outputs to.

  The invention according to claim 2 is the image output system according to claim 1, wherein the control device screens the image data to create halftone dot image data for each basic color. The image output device includes a toner image forming unit that forms a toner image on the photoreceptor based on the created halftone dot image data for each basic color, and each of the formed basic units. Primary transfer means for transferring the toner image for each color onto the intermediate transfer member, secondary transfer means for transferring the transferred toner image to the recording paper, and the transferred toner image on the recording paper A fixing means for fixing and forming the image for printing, and an electrophotographic color laser printer that expresses the gradation of the image for printing by the screened halftone dot. Forming medium, said a said intermediate transfer member of the image output apparatus, the correction image forming means, wherein the includes a toner image forming means and said first transfer means, characterized in that.

  The invention described in claim 3 is the image output system according to claim 2, wherein the color output characteristic is a gradation characteristic representing a density value corresponding to a halftone dot percentage of the halftone dot image data. And the related information includes coefficient information indicating a difference between the gradation characteristics for the intermediate image forming medium and the gradation characteristics for each of the plurality of types of recording paper, and the measurement unit includes the correction information. A density sensor that measures a density value of an image, and the correction unit corrects the gradation characteristics for the designated recording paper based on the coefficient information and the density value measured by the density sensor. It is characterized by that.

  According to a fourth aspect of the present invention, there is provided an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and the image output device with respect to the image output device. An image output system including a control device for transmitting data, wherein the color output characteristics for a predetermined type of recording paper among the plurality of types of recording paper and the colors for each of the other types of recording paper Storage means for storing related information for associating output characteristics, correction image forming means for forming a predetermined correction image on the predetermined type of recording paper, and the color output of the formed correction image Based on the measurement means for measuring the characteristics, the stored related information about the designated recording sheet, and the measured color output characteristics, the designated recording Correction means for correcting the color output characteristics with respect to the image, and the image output device uses the corrected color output characteristics to place the print image based on the image data on the designated recording paper. It outputs to.

  The invention according to claim 5 is the image output system according to claim 4, wherein the control device screens the image data and creates halftone dot image data for each basic color. The image output device includes a toner image forming unit that forms a toner image on the photoreceptor based on the created halftone dot image data for each basic color, and each of the formed basic units. Primary transfer means for transferring the toner image for each color onto the intermediate transfer member, secondary transfer means for transferring the transferred toner image to the recording paper, and the transferred toner image on the recording paper A fixing means for fixing and forming the image for printing, and an electrophotographic color laser printer that expresses the gradation of the image for printing by the screened halftone dot. Image forming means, the toner image forming means, wherein the includes a primary transfer means and the second transfer means, characterized in that.

  The invention according to claim 6 is the image output system according to claim 5, wherein the color output characteristic is a gradation characteristic representing a density value corresponding to a halftone dot percentage of the halftone dot image data. And the related information includes coefficient information representing a difference between the gradation characteristic for the predetermined type of recording paper and the gradation characteristic for the other type of recording paper, and the measuring unit includes the correction A density sensor that measures a density value of the image for use, and the correction unit corrects the gradation characteristics for the designated recording paper based on the coefficient information and the density value measured by the density sensor. It is characterized by.

  The invention according to claim 7 is the image output system according to any one of claims 1 to 6, wherein the designated recording paper is the control device together with the image data. The recording sheet is indicated by the sheet designation information received from the upstream terminal.

  The invention according to claim 8 is the image output system according to any one of claims 1 to 6, wherein the recording paper for outputting the print image based on the image data is designated. It is characterized by having a paper designating means.

  According to a ninth aspect of the present invention, there is provided a control device for transmitting the image data to an image output device for outputting a print image based on the image data on a recording paper designated from a plurality of types of recording paper. A storage means for storing in advance information relating the color output characteristics for the intermediate image forming medium of the image output apparatus and the color output characteristics for each of the plurality of types of recording paper; and the intermediate image Instruction means for instructing the image output apparatus to form a predetermined correction image on a forming medium, the color output characteristics measured for the correction image formed in response to the instruction, and the stored Correction means for correcting the color output characteristics for the designated recording paper based on the related information about the designated recording paper; Sending the color output characteristic to the image output apparatus, and a, and transmitting means for outputting the print image based on the image data on the designated recording sheet, characterized in that.

  According to a tenth aspect of the present invention, there is provided a control device that transmits the image data to an image output device that outputs a print image based on the image data onto a designated recording paper from among a plurality of types of recording paper. In this case, the related information for associating the color output characteristics for the predetermined type of the recording sheet and the color output characteristics for each of the other types of recording sheets among the plurality of types of recording sheets is stored in advance. Measured for storage means, instruction means for instructing the image output apparatus to form a predetermined correction image on the predetermined type of recording paper, and the correction image formed in response to the instruction Based on the color output characteristics and the stored information related to the designated recording paper, the color output characteristics for the designated recording paper are corrected. Correction means; and transmission means for transmitting the corrected color output characteristic to the image output apparatus and outputting the printing image based on the image data on the designated recording paper. It is characterized by that.

  According to an eleventh aspect of the present invention, there is provided an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and the image output device to which the image is output. An image output method by an image output system including a control device for transmitting data, wherein the color output characteristics of the image output device for an intermediate image forming medium and the color for each of the plurality of types of recording paper Storing related information associating with output characteristics; forming a predetermined correction image on the intermediate image forming medium; measuring the color output characteristics of the formed correction image; Based on the stored related information about the designated recording paper stored and the measured color output characteristics, the designated recording paper And correcting the color output characteristics for the output, and outputting the print image based on the image data on the designated recording paper using the corrected color output characteristics. It is characterized by that.

  According to a twelfth aspect of the present invention, there is provided an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and the image output device to which the image An image output method by an image output system including a control device for transmitting data, wherein the color output characteristics for a predetermined type of the recording paper among the plurality of types of recording paper, and other types Storing related information associating the color output characteristics with respect to each of the recording sheets; forming a predetermined correction image on the predetermined type of recording paper; and Based on the step of measuring the color output characteristics, the stored related information about the specified recording paper, and the measured color output characteristics. And correcting the color output characteristics for the designated recording paper, and outputting the printing image based on the image data on the designated recording paper using the corrected color output characteristics. And a step of performing.

  The invention described in claim 13 is a program for causing a computer to execute the image output method according to claim 11 or claim 12.

  The invention according to claim 14 is a storage medium storing the program according to claim 13 in a computer-readable manner.

  According to the image output system, the control device, the image output method, the program, and the storage medium according to claims 1 to 3, claim 9, claim 11, and claim 13 and 14 (limited to the part related to claim 11). In addition, related information that associates the color output characteristics of the image output apparatus with respect to the intermediate image forming medium and the color output characteristics of each type of recording paper is stored in advance, and a predetermined correction image is formed on the intermediate image forming medium. The color output characteristic of the image for correction is measured, the color output characteristic for the designated recording paper is corrected based on the measurement result and related information, and the image for printing is used by using the corrected color output characteristic. Is output. Therefore, the color output characteristics can be easily corrected and compared with the conventional configuration in which an image is formed and measured on both the intermediate image forming medium and the recording paper every time the type of the recording paper changes. This can be done effectively depending on the type of

  In addition, since the correction image is formed on the intermediate image forming medium, the color output characteristic correction process can be executed without consuming recording paper. Is effective. There is also an advantage that the correction process is automated.

  According to the image output system, the control device, the image output method, the program, and the storage medium according to claims 4 to 6, claim 10, claim 12, and claim 13 and 14 (limited to the part related to claim 12), Relevant information that associates the color output characteristics for a predetermined type of recording paper with the color output characteristics for other types of recording paper is stored in advance, and a predetermined correction image is formed on the predetermined type of recording paper. The color output characteristic of the image for correction is measured, the color output characteristic for the designated recording paper is corrected based on the measurement result and related information, and the image for printing is used by using the corrected color output characteristic. Is output. Therefore, it is possible to easily correct the color output characteristics and effectively perform the correction according to the type of recording paper.

  Further, according to the present invention described in claims 1 to 14, when it is desired to output a print image based on image data to another recording paper, by using related information corresponding to the other recording paper, Color output characteristics can be easily corrected without forming a new correction image.

  BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration for suitably implementing an image output system, a control apparatus, an image output method, a computer program for executing the method, and a storage medium storing the program in a computer-readable manner according to the present invention. This will be described in detail with appropriate reference.

<First Embodiment>
Hereinafter, a schematic configuration of the first embodiment of the image output system according to the present invention, an internal configuration of a color laser printer as an image output device of the system, a configuration of a control system of the system, an operation mode of the system, and an operation thereof The effects will be described in order.

[Schematic configuration of image output system]
FIG. 1 shows an example of the configuration and workflow of an image output system 1 according to the present invention. The image output system 1 of this embodiment includes a control device 100 and a color laser printer 200 (image output device). The image output system 1 has a configuration for outputting an image for printing based on image data transmitted from a client terminal 300, which is an upstream terminal, via a network to a recording sheet.

  The client terminal 300 includes at least one computer terminal for the client to perform image editing of image data, for example, imposition work. The image data transmitted from the client terminal 300 to the control device 100 includes comp image data (single page image data before page imposition) formed in a description language such as PostScript, or a print image. Data (image data with multiple impositions). The image data is separated into color plate data of yellow (Y), magenta (M), cyan (C), and black (BK or K) and transmitted from the client terminal 300 to the control device 100.

  The image output system 1 may be further connected to other devices via a network. As such an apparatus, for example, a CTP RIP (CTP raster image processor), a CTP, a DCP control apparatus, a DCP creation apparatus, and the like are generally used. The CTP RIP performs RIP processing on the print image data transmitted from the client terminal 300, and transmits it to the control device 100, CTP, or the DCP control device when high-precision DCP is required. It is. CTP is an apparatus that directly outputs an image based on printing image data transmitted from a CTP RIP to a PS plate. The DCP creation apparatus is an apparatus that outputs, as a DCP, an image based on printing image data transmitted from the CTP RIP via the DCP control apparatus. Here, the DCP control device converts the printing image data transmitted from the CTP RIP into a halftone dot and transmits it to the DCP creation device. The DCP creation device outputs a halftone image based on the image data for printing sent from the DCP control device by forming a halftone dot of each color by exposing a photosensitive material with laser beams having different wavelengths from a plurality of light sources. To create a DCP.

  The “RIP process” described above refers to a process of developing image data described in PostScript or the like into bitmap data that matches the output resolution of the color laser printer 200, CTP, DCP creation apparatus, or the like.

  The control device 100, the client terminal 300, the RIP for CTP, and the DCP control device each operate as a computer terminal, and includes a computer main body, an operation unit such as a mouse and a keyboard, and a display unit such as a monitor. Built-in operation program. Further, the client terminal 300 includes an editing program for performing image editing, and an image input device such as an image scanner.

  The control device 100 of the image output system 1 performs RIP processing on comp image data and print image data transmitted from the client terminal 300 via the network, and also performs dot processing by screening, and outputs instructions. And an output instruction signal including various setting information such as the type, size, and position of the recording paper, and the like are transmitted to the color laser printer 200.

  Note that “screening” refers to a process of forming halftone image data by setting a screen angle and the number of screen lines expressing the gradation of a target image.

  The color laser printer 200 is a multi-function printer including a scanning unit such as an electrophotographic copying unit or an image scanner, for example, according to an output instruction signal transmitted from the control device 100, A halftone image based on the image data for printing is output to the corresponding position on the recording paper.

[Internal configuration of color laser printer]
FIG. 2 is a cross-sectional side view showing an example of the internal configuration of the multicolor multi-beam color laser printer 200. The color laser printer 200 forms a toner image of each basic color by scanning an image forming body with an exposure beam of each basic color controlled based on the image data transmitted from the control device 100, and the like. This is an apparatus that outputs images by sequentially transferring (primary transfer) to an intermediate transfer body and further transferring (secondary transfer) a plurality of toner images transferred to the intermediate transfer body onto a recording sheet. In the color laser printer 200, four colors of yellow (Y), magenta (M), cyan (C), and black (BK or K) are used as the “basic colors” described above.

  The color laser printer 200 includes an apparatus main body 201 that executes an image output process, and an image reading apparatus 202 that is formed on the upper part of the apparatus main body 201 and scans a document to be copied.

  First, the scan function and copy function of the color laser printer 200 will be briefly described. The image reading device 202 includes an automatic document feeder 203 and a document image scanning exposure device 204. The automatic document feeder 203 conveys a document (not shown) placed on the document table d to the document image scanning exposure device 204. The document image scanning exposure device 204 scans one or both sides of the document conveyed by the automatic document feeder 203 by irradiating light, and detects the light reflecting the document image by the line image sensor CCD. To do. The line image sensor CCD photoelectrically converts the detection light into an analog image signal. The analog image signal is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in an image processing unit (not shown) to obtain digital image data.

  The apparatus main body 201 outputs a copy image of the document on a recording sheet based on the digital image data. The copy image output process is the same as the image output process performed by the apparatus main body 201 described below.

  Note that the image output apparatus according to the present invention does not need to have a scan function or a copy function like the color laser printer 200, and only needs to have a printer function for outputting an image based on image data. is there.

  Next, a detailed configuration of the apparatus main body 201 and an image output process executed by the apparatus main body 201 will be described.

  The apparatus main body 201 conveys image forming units 10Y, 10M, 10C, and 10K that form toner images for the respective basic colors, an annular intermediate transfer belt 6 to which the toner images of the respective basic colors are transferred, and recording paper. A sheet transport mechanism (described later) for transferring the toner image on the intermediate transfer belt 6 and a fixing device 17 for fixing the toner image transferred to the recording sheet.

  The intermediate transfer belt 6 constitutes the above-described intermediate transfer member, and is supported in a state of being wound around a plurality of rollers. The intermediate transfer belt 6 is rotated with the rotation of the plurality of rollers.

  An image forming unit 10Y for forming a yellow (Y) image includes a photosensitive drum 1Y as an image forming body on which a Y toner image is formed, and a charging unit 2Y disposed around the photosensitive drum 1Y. And an exposing unit 3Y, a developing unit 4Y, and a cleaning unit 8Y for cleaning the toner adhering to the photosensitive drum 1Y.

  Although not shown, the exposure unit 3Y performs exposure processing by simultaneously irradiating, for example, four laser beams onto the photosensitive drum 1Y based on the image data, thereby performing a Y-color electrostatic latent image for four lines. At the same time. The developing process by the developing unit 4Y is performed by applying a developing bias in which an AC voltage is superimposed on a DC voltage having the same polarity (for example, negative polarity) as that of the toner to be used.

  A primary transfer roller 7Y is provided so as to sandwich the intermediate transfer belt 6 together with the photosensitive drum 1Y. A primary transfer bias having a polarity (for example, positive polarity) opposite to that of the toner is applied to the primary transfer roller 7Y, whereby a Y color toner image formed on the photosensitive drum 1Y by the image forming unit 10Y is transferred to the intermediate transfer belt. 6 is transferred.

  The image forming unit 10M for forming a magenta (M) color image includes a photosensitive drum 1M as an image forming body on which an M color toner image is formed, and a charging unit 2M disposed around the photosensitive drum 1M. And an exposure unit 3M, a developing unit 4M, and a cleaning unit 8M for cleaning the toner adhering to the photosensitive drum 1M.

  Similarly to the configuration relating to the Y color, the exposure unit 3M performs exposure processing by simultaneously irradiating, for example, four laser beams to the photosensitive drum 1M based on the image data, thereby performing electrostatic charging for M colors for four lines. A latent image is formed simultaneously. The developing process by the developing unit 4M is performed by applying a developing bias in which an AC voltage is superimposed on a DC voltage having the same polarity (for example, negative polarity) as that of the toner to be used.

  A primary transfer roller 7M is provided so as to sandwich the intermediate transfer belt 6 together with the photosensitive drum 1M. A primary transfer bias having a polarity (for example, positive polarity) opposite to that of the toner is applied to the primary transfer roller 7M, whereby an M color toner image formed on the photosensitive drum 1M by the image forming unit 10M is transferred to the intermediate transfer belt 6. Is transcribed.

  An image forming unit 10C that forms a cyan (C) color image includes a photosensitive drum 1C as an image forming body on which a C toner image is formed, and a charging unit 2C disposed around the photosensitive drum 1C. And an exposing unit 3C, a developing unit 4C, and a cleaning unit 8C for cleaning the toner adhering to the photosensitive drum 1C.

  Similarly to the configuration relating to the Y color, the exposure unit 3C performs exposure processing by simultaneously irradiating, for example, four laser beams to the photosensitive drum 1C based on the image data, thereby performing C line electrostatic for four lines. A latent image is formed simultaneously. The developing process by the developing unit 4C is performed by applying a developing bias in which an AC voltage is superimposed on a DC voltage having the same polarity (for example, negative polarity) as that of the toner to be used.

  A primary transfer roller 7Y is provided so as to sandwich the intermediate transfer belt 6 together with the photosensitive drums 1C. The primary transfer roller 7Y is applied with a primary transfer bias having a polarity (for example, positive polarity) opposite to that of the toner, whereby a C-color toner image formed on the photosensitive drum 1C by the image forming unit 10C is applied to the intermediate transfer belt 6. Transcribed.

  The image forming unit 10K that forms a black (K) image includes a photosensitive drum 1K as an image forming body on which a K-color toner image is formed, and a charging unit 2K disposed around the photosensitive drum 1K. And an exposure unit 3K, a developing unit 4K, and a cleaning unit 8K for cleaning the toner adhering to the photosensitive drum 1K.

  Similarly to the configuration relating to the Y color, the exposure unit 3K performs exposure processing by simultaneously irradiating, for example, four laser beams to the photosensitive drum 1K based on the image data, thereby performing K-line electrostatic for four lines. A latent image is formed simultaneously. The developing process by the developing unit 4K is performed by applying a developing bias in which an AC voltage is superimposed on a DC voltage having the same polarity (for example, negative polarity) as the polarity of the toner to be used.

  A primary transfer roller 7K is provided so as to sandwich the intermediate transfer belt 6 with each photosensitive drum 1K. The primary transfer roller 7K is applied with a primary transfer bias having a polarity (for example, positive polarity) opposite to that of the toner, whereby a K-color toner image formed on the photosensitive drum 1K by the image forming unit 10K is applied to the intermediate transfer belt 6. Transcribed.

  In this way, the primary transfer bias (transfer current) can be applied to the Y toner image, the M toner image, the C toner image, and the K toner image by the primary transfer rollers 7Y, 7M, 7C, and 7K. As a result, the images are transferred onto the rotating intermediate transfer belt 6 so as to overlap each other. As a result, a combined toner image obtained by combining the toner images of the respective colors is formed on the intermediate transfer belt 6.

  The toner remaining on the peripheral surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K after the primary transfer is cleaned by the drum cleaning units 8Y, 8M, 8C, and 8K, respectively, and the image forming units 10Y, 10M, 10C, At 10K, the process proceeds to the next image forming process.

  Each of the paper feed cassettes 20A, 20B, and 20C stores recording paper P of different types and sizes. The recording paper P is taken out one by one by a feed roller 21 provided in each of the paper feed cassettes 20A, 20B, and 20C, and a secondary transfer roller is fed by a paper feed roller 22A, transport rollers 22B, 22C, and 22D, a registration roller 23, and the like. It is conveyed to 7A.

  The secondary transfer roller 7 </ b> A transfers the composite toner image formed on the intermediate transfer belt 6 to one surface (front surface) of the recording paper P by applying a transfer current for secondary transfer. The recording paper P onto which the composite toner image has been transferred is sent to the fixing device 17 for fixing processing, and is sandwiched between the paper discharge rollers 24 and placed on the paper discharge tray 25 outside the apparatus.

  Here, the toner remaining on the intermediate transfer belt 6 after the secondary transfer is removed by the belt cleaning unit 8A.

  Further, the recording paper stored in each of the paper feed cassettes 20A, 20B, and 20C is selectively transported to the secondary transfer roller 7A, the feed roller 21, the paper feed roller 22A, the transport rollers 22B, 22C, and 22D, the registration roller 23, and the like. Further, the paper discharge roller 24 for transporting the recording paper subjected to the secondary transfer process and the fixing process to the paper discharge tray 25 constitutes the paper transport mechanism described above.

  When images are output on both sides of the recording paper P, the recording paper P discharged from the fixing device 17 is branched from the paper discharge path by the branching unit 26, and a refeed mechanism (ADU mechanism) by the circulation paper passage path 27A. ) Is sent to the reverse conveyance path 27B. The recording paper P is turned upside down by the reversal conveyance path 27B, and is sent again to the conveyance roller 22D via the refeed conveyance unit 27C. Then, the recording paper P whose front and back sides are reversed is sent to the secondary transfer roller 7A through the registration roller 23, and the composite toner image is transferred to the other side (back side), and after fixing processing, is transferred to the paper discharge tray 25. Discharged.

  The color laser printer 200 according to the present embodiment is provided with a density sensor 28 that measures the density of the synthesized toner image formed on the intermediate transfer belt 6. The density sensor 28 is provided in the vicinity of the intermediate transfer belt 6 in the apparatus main body 201, for example, below the K-color image forming unit 10K. For example, the density sensor 28 emits light toward the composite toner image on the intermediate transfer belt 6. The reflected light is analyzed to obtain a density value (for example, Y density, M density, C density).

  The image output process of the color laser printer 200 is executed under the control of the control unit 15 disposed in the apparatus main body 201. The control unit 15 is configured by an arithmetic control device such as a CPU. Details of various control modes by the control unit 15 will be described later.

[Control system configuration of image output system]
The block diagram shown in FIG. 3 represents a schematic configuration of an example of a control system of the image output system 1 of the present embodiment. Hereinafter, control systems of the control device 100 and the color laser printer 200 will be described.

[Control system of control device]
The control device 100 includes a control unit 110 that controls each part of the system in a processing mode according to the present invention, an image storage unit 120 that stores image data transmitted from the client terminal 300, and a correction process (described later). ) Are recorded between the correction information storage unit 130, the operation unit 140 for performing various input operations related to the system 1, the display monitor 150 for displaying various images, and the client terminal 300 and the color laser printer 200. A transmission / reception unit 160 that controls transmission / reception of data is included.

(Control part)
The control unit 110 is configured by an arithmetic control device such as a CPU, and controls each part of the device by executing a computer program stored in a program storage unit (not shown) such as a ROM or a hard disk drive. The control unit 110 operates as a halftone processing unit 111 and a correction unit 112 according to the computer program. The correction unit 112 includes a correction image formation instruction unit 113 and a gradation correction unit 114.

  The halftone processing unit 111 constitutes the halftone processing means of the present invention, and executes processing for screening image data and creating halftone image data for each of the basic colors Y, M, C, and K. . More specifically, the halftone processing unit 111 prints (original) image data having a gradation such as a photograph or an illustration with a collection of fine dots (halftone dots, halftone dots, etc.). A process of converting to image data (halftone dot image data) is performed. The density (gradation) of the output image is represented by a change in the halftone dot value of the halftone dot image data.

  The correction unit 112 constitutes a correction unit of the present invention, and performs processing for correcting the gradation of the output color of the color laser printer 200. The correction unit 112 performs the correction process using the following correction image formation instruction unit 113 and gradation correction unit 114.

  The correction image formation instructing unit 113 of the correction unit 112 constitutes an instructing unit according to the present invention, and a signal for instructing to form a predetermined correction image is sent via the transmission / reception unit 160 to the color laser printer 200. Execute the process to send to. As the correction image, a color patch image in which a large number of patches composed of combinations of Y, M, and C are output over the entire color space can be used.

  The gradation correction unit 114 of the correction unit 112 outputs the output color based on the density value obtained by measuring the correction image, information stored in the correction information storage unit 130, etc., as will be described in detail later. To correct the tone. Note that the density value of the correction image is measured by the density sensor 28 of the color laser printer 200 described above.

(Image storage unit)
The image storage unit 120 includes a storage device such as a hard disk drive or an image memory, and is used to store image data G transmitted from the client terminal 300. Recording processing and reading processing of various data such as image data with respect to the image storage unit 120 are executed by the control unit 110. A hot folder in which image data of a proof image is stored may be provided in a predetermined area (directory) of the image storage unit 120. In that case, the control unit 110 monitors the hot folder and recognizes the image data stored in the hot folder as a proof use.

(Correction information storage unit)
The correction information storage unit 130 constitutes a storage unit according to the present invention, and includes a storage device such as a hard disk drive. The correction information storage unit 130 stores correction coefficient information 131 and paper designation information 132 that are used for correction processing by the correction unit 112 of the control unit 110.

  The correction coefficient information 131 is coefficient information that associates the gradation characteristics when a toner image is formed on the intermediate transfer belt 6 of the color laser printer 200 with the gradation characteristics when an image is output on the recording paper P. The coefficient information is provided for each type of recording paper P.

  The gradation characteristic (gamma characteristic) is an example of the color output characteristic of the present invention, and is data expressed as a density value for each halftone dot value of the halftone image data. Further, the correction coefficient information 131 constitutes related information and coefficient information referred to in the present invention. Further, the related information does not need to be correction coefficients (coefficient information) as will be described later, and if it is data that associates the color output characteristics with respect to the intermediate transfer belt 6 and the color output characteristics with respect to the storage paper P, the form thereof Does not matter.

  FIG. 4 shows an outline of the correction coefficient information 131. The figure shows gradation characteristic data for the intermediate transfer belt 6 (left middle graph) and gradation characteristic data for the different types of first recording paper and second recording paper (upper left and lower graphs). ) Is shown.

  The gradation characteristic data for the intermediate transfer belt 6 is information used as a reference when correcting the gradation characteristics corresponding to the first and second recording sheets, and is referred to as reference gradation characteristic data. This reference gradation characteristic data is assumed to have linear gradation response characteristics as shown in FIG.

  On the other hand, the gradation characteristic data (referred to as the first gradation characteristic data) for the first recording paper has a linear response characteristic like the reference gradation characteristic data, but has the same dot percentage. Assume that the corresponding density value is lower than the reference gradation characteristic data. That is, in the case of outputting with the same halftone dot percentage, the density of the output color on the first recording sheet is lower than the output color on the intermediate transfer belt 6. Also, the gradation characteristic data (referred to as second gradation characteristic data) for the second recording paper is assumed to have a curved response characteristic unlike the reference gradation characteristic data. Such a difference in gradation characteristics is caused by the material of the recording paper, the condition of the paper surface (roughness, presence / absence of coat, etc.), and the like.

  The correction coefficient information 131 includes “coefficient 1” 131a and “coefficient 2” 131b as correction coefficients for gradation correction. Here, the case where two types of recording paper are used will be described. However, when more types of recording paper are used, the number of correction coefficients corresponding to the type is included in the correction coefficient information 131. It will be.

  “Coefficient 1” 131a is a coefficient representing a difference of the first gradation characteristic data with respect to the reference gradation characteristic data, in other words, a conversion coefficient for converting the reference gradation characteristic data into the first gradation characteristic data. It acts as. In this case, since both response characteristics are linear, the “coefficient 1” 131a is a certain positive real value.

  The “coefficient 2” 131b is a coefficient representing the difference between the second gradation characteristic data and the reference gradation characteristic data, in other words, for converting the reference gradation characteristic data into the second gradation characteristic data. Since it functions as a conversion coefficient and the second gradation characteristic data is curvilinear, it is expressed as a function having halftone dot percentage as a variable.

  Such “coefficients” included in the correction coefficient information 131 are acquired in advance for various recording sheets P used by the color laser printer 200. The “coefficient” can be acquired, for example, by outputting the above-described color patch image on various recording papers P and measuring the density value.

  The paper designation information 132 is information for designating the recording paper P for outputting an image based on the image data. When the recording paper P is designated at the client terminal 300, the paper designation information 132 is transmitted along with the image data and is stored in the correction information storage unit 130. When the recording paper P is designated by the control device 100 or the color laser printer 200, the designated content is stored as the paper designation information 132.

  Note that information storage processing, reading processing, and the like with respect to the correction information storage unit 130 are executed by the control unit 110.

(Operation section)
The operation unit 140 constitutes the paper designation unit of the present invention, and is composed of an arbitrary device for an operator to perform a desired input operation, such as an input device such as a keyboard and a pointing device such as a mouse and a trackball. The For example, the operator designates the use of the print image based on the image data while referring to a predetermined operation screen (not shown) displayed on the display monitor 150.

  For specifying the recording paper P, for example, an operation screen including a paper designating check box and pull-down menu is displayed on the display monitor 150, and the operation unit 140 is operated to select a desired recording paper P with a check box, pull-down menu, and the like. It is made by selecting and specifying from.

(Display monitor and transmitter / receiver)
The display monitor 150 is configured by a normal monitor device connected to a computer such as an LCD or a CRT. The display monitor 150 displays various screens (such as the operation screen described above) in accordance with instructions from the control unit 110. The transmission / reception unit 160 is a transmission unit according to the present invention including a transmission / reception interface circuit. The transmission / reception unit 160 executes processing for transmitting various data to the color laser printer 200 and the client terminal 300 according to instructions from the control unit 110, and performs color processing. A process of receiving various data transmitted from the laser printer 200 and the client terminal 300 and sending it to the control unit 110 is executed.

[Color laser printer control system]
Next, the configuration of the control system of the color laser printer 200 will be described. The control system of the color laser printer 200 includes the control unit 15 and the density sensor 28 described above, an image output unit 220 that outputs an image for printing based on (halftone dot) image data transmitted from the control device 100, and the image output. A sheet supply unit 30 that supplies the recording sheet P to the unit 220 and a transmission / reception unit 230 including a transmission / reception interface circuit that transmits and receives various data to and from the control device 100 are provided. Here, the density sensor 28 constitutes the measuring means of the present invention.

(Control part)
The control unit 15 includes an arithmetic control device such as a CPU, and controls each unit of the color laser printer 200 according to a computer program. Note that the computer program executed by the control unit 15 may be stored in the color laser printer 200 itself, or may be the above-described computer program stored in the control unit 110 of the control device 100.

  The control unit 15 includes an output setting changing unit 211 that changes various output setting values when the color laser printer 200 outputs a printing image in accordance with instructions from the control device 100. Examples of the output set value include gradation characteristics (gamma characteristics), toner concentrations of the image forming units 10Y, 10M, 10C, and 10K, charging potentials of the charging units 2Y, 2M, 2C, and 2K, exposure units 3Y, 3M, There are exposure amounts of 3C and 3K, a current value of a transfer current applied by the primary transfer rollers 7Y, 7M, 7C and 7K, a current value of a transfer current applied by the secondary transfer roller 7A, and the like.

(Image output part)
The image output unit 220 includes a toner image forming unit 221 that forms toner images of the basic colors Y, M, C, and K based on the halftone image data received from the control device 100, and the toner image is transferred to the intermediate transfer belt 6. And a secondary transfer unit 223 that transfers the toner image transferred to the intermediate transfer belt 6 to the recording paper P. As described above, the toner image transferred to the recording paper P is subjected to a fixing process by the fixing device shown in FIG. The image output unit 220 constitutes a correction image forming unit of the present invention.

  The toner image forming unit 221 constitutes the toner image forming unit of the present invention, and is configured by the image forming units 10Y, 10M, 10C, and 10K of the basic colors shown in FIG. The primary transfer unit 222 constitutes a primary transfer unit of the present invention, and intermediately transfers Y, M, C, and K toner images formed by the image forming units 10Y, 10M, 10C, and 10K, respectively. Consists of primary transfer rollers 7Y, 7M, 7C, and 7K that transfer to the belt 6. Further, the secondary transfer unit 223 constitutes a secondary transfer unit of the present invention, and is constituted by a secondary transfer roller 7A. Further, in the present invention, the photosensitive drums 1Y, 1M, 1C, and 1K constitute photosensitive members, the intermediate transfer belt 6 constitutes an intermediate transfer member and an intermediate image forming medium, and the fixing device 17 constitutes a fixing unit.

(Paper supply unit)
The paper supply unit 30 stores the recording paper P stored in the paper feeding cassettes 20A, 20B, and 20C, and the image output unit 220. And a paper transport mechanism 31 that selectively transports the secondary transfer roller 7A. Although not shown in FIG. 3, the paper supply unit 30 is connected to the control unit 15 and conveys the recording paper P to the image output unit 220 according to the control of the control unit 15.

  Various types of recording paper P such as art paper, coated paper, high quality paper, and medium quality paper are stored in the paper feed cassettes 20A, 20B, and 20C. Information on the type and size of the recording paper P stored in each of the paper feeding cassettes 20A, 20B, and 20C is recorded in the control unit 15 and the control unit 110 of the control device 100.

  The paper transport mechanism 31 includes a feed roller 21, a paper feed roller 22A, transport rollers 22B, 22C, 22D, a registration roller 23, and the like. The paper transport mechanism 31 selects the type of recording paper P indicated by the paper specification information 132 from the paper feed cassettes 20A, 20B, and 20C and transports it to the image output unit 220.

[Operation mode of image output system]
An example of the operation mode of the image output system 1 of the present embodiment will be described with reference to the flowchart shown in FIG.

  The correction coefficient information 131 as described in FIG. 4 is stored in the correction information storage unit 130 of the control device 100 (S1). This procedure is performed before the system 1 actually outputs an image. Hereinafter, the procedure proceeds to a processing procedure related to actual image output.

  First, the control unit 110 of the control device 100 stores the image data G transmitted from the client terminal 300 in the image storage unit 120 (S2). Next, the sheet designation information 132 for designating the recording sheet P on which the printing image based on the image data G is output is stored in the correction information storage unit 130 (S3). When paper designation information is attached to the image data G, the paper designation information is stored. Further, when the operator operates and designates the operation unit 140, the designated content is stored.

  Subsequently, the control unit 110 converts the image data G into halftone image data by the halftone processing unit 111 (S4). Further, the correction image formation instructing unit 113 transmits an instruction signal for forming a correction image (for example, the above-described color patch image) to the color laser printer 200 via the transmission / reception unit 160 (S5).

  Upon receiving the instruction signal from the control device 100, the control unit 15 of the color laser printer 200 controls the image output unit 220 to form a correction image on the intermediate transfer belt 6 (S6). At this time, for example, the image output unit 220 forms a toner image of each basic color based on the halftone dot image data of the color patch image by the toner image forming unit 221 and also uses the primary transfer unit 222 for each basic color. By transferring the toner images to the intermediate transfer belt 6, a color patch image (a synthesized toner image) as a correction image is formed on the intermediate transfer belt 6.

  The control unit 15 controls the density sensor 28 to measure the correction image on the intermediate transfer belt 6 and acquire the density value (S7). The measurement result is transmitted by the control unit 15 to the control device 100 via the transmission / reception unit 230.

  The gradation correction unit 114 of the control unit 110 of the control device 100 corrects gradation characteristics for the recording sheet P indicated by the sheet designation information 132 based on the correction coefficient information 131 and the density value measured for the correction image. A value is obtained (S8).

  More specifically, the gradation correction unit 114 selects and calls the correction coefficient for the recording paper P indicated in the paper designation information 132 from the correction coefficient information 131, and applies the correction coefficient acquired in step S7 to the density value of the correction image. By multiplying the correction coefficient, the gradation characteristic correction value for the designated recording paper P is calculated. Here, since a color patch image is used as a correction image, measured values of density values (that is, gradation characteristics) with respect to various dot percentages are obtained, and correction values thereof are obtained. Thereby, the correction value of the gradation characteristic for the recording paper P in consideration of the displacement of the gradation characteristic for the correction image is acquired.

  For example, in the case of FIG. 4, when the designated recording paper P is the first recording paper, the gradation correction unit 114 calls “coefficient 1” 131a from the correction coefficient information 131 and is measured in step S7. The correction value is obtained by multiplying the density value (gradation characteristic) by the “coefficient 1” 131a. When the second recording sheet is designated, the “coefficient 2” 131b is called, and the correction value is obtained by multiplying the measured gradation characteristic by the “coefficient 2” 131b for each halftone dot value. Ask for.

  Following the correction process in step S8, the control unit 110 transmits the correction value of the gradation characteristic to the color laser printer 200 together with the halftone image data created in step S4 (S9). At this time, information regarding various output conditions such as the sheet designation information 132 and the number of output sheets is also transmitted to the color laser printer 200.

  The output setting change unit 211 of the control unit 15 of the color laser printer 200 changes the output setting of the image output unit 220 in accordance with the correction value of the gradation characteristic (S10), and the image output unit 220 reads the paper designation information 132. A printing image based on the halftone dot image data is output on the recording paper P corresponding to (S11). Thus, the image output process based on the image data is finished, and the process proceeds to the process for the next image data.

[Operation and effect of image output system]
The operation and effect of the image output system 1 as described above will be described. The image output system 1 is provided with a correction coefficient corresponding to the type of recording paper in advance, forms a correction image on the intermediate transfer belt 6 at the time of image output, and displays density values (scale levels) corresponding to various dot percentages. Tone characteristics), and the gradation characteristics are corrected using a correction coefficient corresponding to the recording paper on which the printing image is output. Accordingly, it is possible to easily perform gradation correction as compared with the conventional configuration in which an image is formed on both the intermediate transfer belt 6 and the recording paper every time the type of the recording paper is changed and density measurement is performed. is there. In addition, since correction coefficients are prepared for each type of recording paper, gradation correction can be effectively performed regardless of the recording paper stored in the color laser printer 200. it can.

  In addition, since the gradation is corrected using the measured value of the density of the correction image formed on the intermediate transfer belt 6, the correction process can be executed without consuming recording paper. This is effective in terms of cost and resource saving. There is also an advantage that the correction process is automated.

  In addition, when outputting a print image based on the image data to another recording paper, a gradation can be easily adjusted without forming a new correction image by using a correction coefficient corresponding to the other recording paper. Can be corrected.

<Second Embodiment>
A second embodiment of the image output system according to the present invention will be described. Components similar to those in the first embodiment will be described with the same reference numerals.

  The image output system of the present embodiment has a system configuration similar to that of the image output system 1 of the first embodiment shown in FIG. 1, and includes a control device that performs various processes on image data transmitted from a client terminal, And a color laser printer that outputs a printing image based on the image data processed by the control device. The density sensor 28 (see the first embodiment) that measures the density of the image on the intermediate transfer belt 6 is not particularly required for the color laser printer of this embodiment.

[Control system configuration of image output system]
FIG. 6 shows the configuration of the control system of the image output system 1 ′ of the present embodiment. The control device 100 ′ and the color laser printer 200 ′ of the image output system 1 ′ are provided with almost the same control system as that of the image output system 1 of the first embodiment.

[Control system of control device]
The control device 100 ′ includes a control unit 110, an image storage unit 120, a correction information storage unit 130, an operation unit 140, a display monitor 150, and a transmission / reception unit 160. The control device 100 ′ is connected to a densitometer 400 for measuring the density value of an image (for example, a color patch image) output on the recording paper P, and the measurement result is input to the control device 100 ′. It has come to be. The densitometer 400 constitutes the measuring means of the present invention.

  In the correction information storage unit 130, correction coefficient information 131 and paper designation information 132 are stored. The correction coefficient information 131 according to the present embodiment is coefficient information that associates gradation characteristics when an image is output on a certain recording sheet (reference recording sheet) with gradation characteristics when an image is output on another recording sheet. It is. The coefficient information is provided for each type of recording paper (except for the reference recording paper itself). Note that the reference recording sheet corresponds to a predetermined type of recording sheet in the present invention.

  FIG. 7 shows an outline of the correction coefficient information 131 of the present embodiment. In the figure, reference gradation characteristic data (left upper graph) of the first recording sheet as the reference recording sheet and gradation characteristic data (leftward) of the second recording sheet as the other recording sheet are shown. An example of the lower graph) is shown. The gradation characteristic data for the first recording paper has a linear response characteristic. Further, the gradation characteristic data for the second recording sheet has a curved response characteristic unlike the reference gradation characteristic data.

  The correction coefficient information 131 includes a “coefficient” 131c as a correction coefficient for gradation correction. Here, the case where two types of recording paper are used will be described. However, when more types of recording paper are used, the number of correction coefficients corresponding to the type is included in the correction coefficient information 131. It will be.

  The “coefficient” 131c is a coefficient representing a difference in the gradation characteristic data of the second recording paper with respect to the reference gradation characteristic data, in other words, converting the reference gradation characteristic data into the gradation characteristic data of the second recording paper. The former is linear and the latter is curvilinear, so it is expressed as a function with halftone dot percentage as a variable.

  The “coefficient” 131c is acquired in advance for various recording sheets P used by the color laser printer 200 ′. The “coefficient” can be acquired, for example, by outputting the above-described color patch image on various recording papers P and measuring the density value.

[Operation mode of image output system]
The operation mode of the image output system 1 ′ having the above configuration will be described with reference to the flowchart shown in FIG.

  The correction coefficient information 131 as described in FIG. 7 is stored in the correction information storage unit 130 of the control device 100 ′ (S21). This procedure is performed before the system 1 actually outputs an image. Hereinafter, the procedure proceeds to a processing procedure related to actual image output.

  First, the control unit 110 of the control device 100 ′ stores the image data G transmitted from the client terminal 300 in the image storage unit 120 (S22). Next, the sheet designation information 132 for designating the recording sheet P on which the printing image based on the image data G is output is stored in the correction information storage unit 130 (S23).

  Subsequently, the control unit 110 converts the image data G into halftone image data by the halftone processing unit 111 (S24). In addition, the control unit 110 causes the correction image formation instruction unit 113 to transmit an instruction signal for forming a correction image (color patch image) to the color laser printer 200 ′ (S25).

  For example, the control unit 15 of the color laser printer 200 'controls the paper supply unit 30 so as to convey the reference recording paper to the image output unit 220 (S26), and in response to the instruction signal, the reference recording paper. The image output unit 220 is controlled to output the correction image (color patch image) on the top (S27). At this time, the image output unit 220 forms a toner image of each basic color based on the dot image data of the color patch image by the toner image forming unit 221, and the toner image of each basic color by the primary transfer unit 222. Each color is transferred to the intermediate transfer belt 6, the toner image on the intermediate transfer belt 6 is transferred to the reference recording paper by the secondary transfer unit 223, and the fixing device 17 performs fixing processing, whereby a color patch as a correction image is obtained. An image is formed on a reference recording sheet. The reference recording paper on which the color patch image is formed is placed on the paper discharge tray 25.

  When the operator operates the densitometer 400 to measure the density value (tone characteristics) of the correction image on the reference recording paper, the measurement result is input to the control device 100 '(S28).

  The gradation correction unit 114 of the control unit 110 obtains a correction value of gradation characteristics for the recording paper P indicated by the paper designation information 132 based on the correction coefficient information 131 and the measured density value of the correction image ( S29).

  More specifically, the gradation correction unit 114 selects and calls the correction coefficient for the recording paper P indicated in the paper designation information 132 from the correction coefficient information 131, and obtains the density value of the correction image (step S28). The correction value is calculated by multiplying the gradation characteristic) by the correction coefficient.

  For example, in the case of FIG. 7, when the second recording sheet is designated, the correction value is obtained by multiplying the measured gradation characteristic by the “coefficient” 131c. If the designated recording paper P is the first recording paper (that is, the reference recording paper), the density value (gradation characteristics) measured in step S28 is used as it is.

  Following the correction processing in step S29, the control unit 110 transmits the correction value of the gradation characteristic to the color laser printer 200 together with the halftone image data created in step S24 (S30). At this time, information regarding various output conditions such as the sheet designation information 132 and the number of output sheets is also transmitted to the color laser printer 200.

  The output setting changing unit 211 of the control unit 15 of the color laser printer 200 changes the output setting of the image output unit 220 according to the correction value of the gradation characteristic (S31), and the image output unit 220 uses the paper designation information 132. A printing image based on the halftone dot image data is output on the recording paper P corresponding to (S32). Thus, the image output process based on the image data is finished, and the process proceeds to the process for the next image data.

[Operation and effect of image output system]
The image output system 1 ′ of the present embodiment is provided with a correction coefficient corresponding to the type of recording paper in advance, and forms a correction image on a certain recording paper (for example, a reference recording paper) at the time of image output. The density value (gradation characteristic) corresponding to the halftone dot percentage is measured, and the gradation characteristic is corrected by using a correction coefficient corresponding to the recording paper on which the printing image is output. . Therefore, it is possible to easily perform gradation correction. In addition, since correction coefficients are prepared for each type of recording paper, tone correction can be effectively performed regardless of the recording paper stored in the color laser printer 200 '. Can do.

  In addition, when outputting a print image based on the image data to another recording paper, a gradation can be easily adjusted without forming a new correction image by using a correction coefficient corresponding to the other recording paper. Can be corrected.

  Further, if an inexpensive recording sheet for forming the correction image is selected, the cost for the correction process can be reduced.

<Program and storage medium>
The processing performed in the image output systems 1, 1 ′ described in the above embodiment is executed by the computer main body of the control devices 100, 100 ′ and the computer (control unit 15) built in the color laser printer 200, 200 ′. The program for this is installed in these apparatuses, or is stored in a storage medium connected to these apparatuses. In the latter case, a separate storage medium may be connected to each device, or both devices may be connected to a common storage medium. When each device is configured to execute an individual program, each device operates in conjunction with each program. Each device implements the above-described processing (see FIGS. 5 and 8) by the control units 110 and 15 reading and executing the program.

  Specific examples of the storage medium for storing the program include, for example, a semiconductor memory such as a ROM, a RAM, and a flash memory, a memory device such as an integrated circuit, an optical disk, a magneto-optical disk (CD-ROM / CD / ROM), and the like. DVD-RAM / DVD-ROM / MO, etc.) and magnetic storage media (magnetic disk: hard disk / floppy (registered trademark) disk / ZIP, etc.).

<Other variations>
The configuration detailed in the above embodiment is merely an example for carrying out the present invention, and various modifications can be made within the scope of the gist of the present invention.

  For example, by providing correction coefficient information 131 that includes both of the correction coefficients shown in FIGS. 4 and 7, the correction processes of the first and second embodiments may be selectively executed. The selection of the correction process to be performed is performed, for example, when the operator operates the operation unit 140.

  In the above-described embodiment, a correction coefficient is provided for each recording sheet used in the color laser printers 200 and 200 '. However, a plurality of recording sheets having similar properties are grouped and each group is recorded. A correction coefficient may be provided for.

  In the second embodiment, the density value of the correction image formed on the recording paper may be automatically measured. For this purpose, for example, the densitometer 400 is disposed at a position facing the recording paper placed on the paper discharge tray 25 of the color laser printer 200 ′, and the recording paper on which the correction image is formed is discharged. Corresponding to the above, concentration measurement may be performed. Control of such automatic measurement processing is performed by the control unit 110 of the control device 100 ′ and the control unit 15 of the color laser printer 200 ′.

  In the above embodiment, the gradation characteristic (gamma characteristic) is applied as the color output characteristic related to the correction process, but the color output characteristic of the present invention is not limited to this. For example, the toner density of the image forming units 10Y, 10M, 10C, and 10K of the color laser printers 200 and 200 ′, the charging potential of the charging means 2Y, 2M, 2C, and 2K, the exposure amount of the exposure means 3Y, 3M, 3C, and 3K, Various characteristics such as a current value of a transfer current applied by the primary transfer rollers 7Y, 7M, 7C, and 7K and a current value of a transfer current applied by the secondary transfer roller 7A can be corrected.

1 is a diagram illustrating an example of an overall configuration and a workflow of an image output system according to a first embodiment of the present invention. 1 is a cross-sectional side view illustrating an example of an internal configuration of a color laser printer included in a first embodiment of an image output system according to the present invention. It is a block diagram showing an example of the composition of the control system of a 1st embodiment of the image output system concerning the present invention. It is a figure for demonstrating the outline | summary of the correction coefficient information of 1st Embodiment of the image output system which concerns on this invention. It is a flowchart showing an example of the operation | movement aspect of 1st Embodiment of the image output system which concerns on this invention. It is a block diagram showing an example of a structure of the control system of 2nd Embodiment of the image output system which concerns on this invention. It is a figure for demonstrating the outline | summary of the correction coefficient information of 2nd Embodiment of the image output system which concerns on this invention. It is a flowchart showing an example of the operation | movement aspect of 2nd Embodiment of the image output system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image output system 100 Control apparatus 110 Control part 111 Halftone processing part 112 Correction | amendment part 113 Image formation instruction | indication part for correction | amendment 114 Tone correction | amendment part 120 Image memory | storage part 130 Correction | amendment information memory | storage part 131 Correction coefficient information 131a Coefficient 1
131b coefficient 2
132 Paper designation information 140 Operation unit 150 Display monitor 160 Transmission / reception unit 200 Color laser printer 15 Control unit 211 Output setting change unit 220 Image output unit 221 Toner image formation unit 222 Primary transfer unit 6 Intermediate transfer belt 223 Secondary transfer unit 230 Transmission / reception unit 28 Density sensor 30 Paper supply unit 20A to 20C Paper feed cassette 31 Paper transport mechanism G Image data P Recording paper 300 Client terminal

Claims (14)

An image including an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and a control device that transmits the image data to the image output device An output system,
Storage means for storing in advance related information that associates color output characteristics of the image output apparatus with respect to the intermediate image forming medium and color output characteristics with respect to each of the plurality of types of recording paper;
Correction image forming means for forming a predetermined correction image on the intermediate image forming medium;
Measuring means for measuring the color output characteristics of the formed correction image;
Correction means for correcting the color output characteristics for the designated recording paper based on the stored related information about the designated recording paper and the measured color output characteristics;
With
The image output device outputs the printing image based on the image data on the designated recording paper using the corrected color output characteristic.
An image output system characterized by that. The control device comprises halftone dot processing means for screening the image data and creating halftone dot image data for each basic color,
The image output device includes a toner image forming unit that forms a toner image based on the created halftone dot image data for each basic color on a photosensitive member, and a toner image for each basic color that is formed. Primary transfer means for transferring onto the intermediate transfer member, secondary transfer means for transferring the transferred toner image to the recording paper, and fixing the transferred toner image on the recording paper for the printing An electrophotographic color laser printer that includes a fixing unit that forms an image, and expresses the gradation of the image for printing by the screened halftone dots.
The intermediate image forming medium is the intermediate transfer member of the image output device;
The correction image forming unit includes the toner image forming unit and the primary transfer unit.
The image output system according to claim 1. The color output characteristic is a gradation characteristic representing a density value corresponding to a halftone dot percentage of the halftone dot image data,
The related information includes coefficient information representing a difference between the gradation characteristics for the intermediate image forming medium and the gradation characteristics for each of the plurality of types of recording paper,
The measurement means includes a density sensor that measures a density value of the correction image,
The correction unit corrects the gradation characteristics for the designated recording paper based on the coefficient information and the density value measured by the density sensor.
The image output system according to claim 2. An image including an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and a control device that transmits the image data to the image output device An output system,
Storage means for storing, in advance, related information associating color output characteristics for a predetermined type of recording paper among the plurality of types of recording paper and color output characteristics for each of other types of recording paper;
Correction image forming means for forming a predetermined correction image on the predetermined type of recording paper;
Measuring means for measuring the color output characteristics of the formed correction image;
Correction means for correcting the color output characteristics for the designated recording paper based on the stored related information about the designated recording paper and the measured color output characteristics;
With
The image output device outputs the printing image based on the image data on the designated recording paper using the corrected color output characteristic.
An image output system characterized by that. The control device comprises halftone dot processing means for screening the image data and creating halftone dot image data for each basic color,
The image output device includes a toner image forming unit that forms a toner image based on the created halftone dot image data for each basic color on a photosensitive member, and a toner image for each basic color that is formed. Primary transfer means for transferring onto the intermediate transfer member, secondary transfer means for transferring the transferred toner image to the recording paper, and fixing the transferred toner image on the recording paper for the printing An electrophotographic color laser printer that includes a fixing unit that forms an image, and expresses the gradation of the image for printing by the screened halftone dots.
The correction image forming unit includes the toner image forming unit, the primary transfer unit, and the secondary transfer unit.
The image output system according to claim 4. The color output characteristic is a gradation characteristic representing a density value corresponding to a halftone dot percentage of the halftone dot image data,
The related information includes coefficient information representing a difference between the gradation characteristic for the predetermined type of recording paper and the gradation characteristic for the other type of recording paper,
The measurement means includes a density sensor that measures a density value of the correction image,
The correction unit corrects the gradation characteristics for the designated recording paper based on the coefficient information and the density value measured by the density sensor.
The image output system according to claim 5.   7. The designated recording sheet is a recording sheet indicated by sheet designation information received from an upstream terminal together with the image data by the control device. Image output system.   The image output system according to any one of claims 1 to 6, further comprising a sheet designating unit for designating the recording sheet on which the printing image based on the image data is output. A control device that transmits the image data to an image output device that outputs a print image based on image data onto a designated recording paper among a plurality of types of recording paper,
Storage means for storing, in advance, related information for associating the color output characteristics for the intermediate image forming medium of the image output apparatus with the color output characteristics for each of the plurality of types of recording paper;
Instruction means for instructing the image output apparatus to form a predetermined correction image on the intermediate image forming medium;
Based on the color output characteristics measured for the correction image formed in response to the instruction and the related information about the stored recording sheet specified, the specified recording paper for the specified recording paper Correction means for correcting the color output characteristics;
Transmitting means for transmitting the corrected color output characteristics to the image output device and outputting the printing image based on the image data on the designated recording paper;
The control apparatus characterized by the above-mentioned. A control device that transmits the image data to an image output device that outputs a print image based on image data onto a designated recording paper among a plurality of types of recording paper,
Storage means for storing, in advance, related information associating the color output characteristics for a predetermined type of the recording paper and the color output characteristics for each of the other types of recording paper among the plurality of types of recording paper;
Instruction means for instructing the image output apparatus to form a predetermined correction image on the predetermined type of recording paper;
Based on the color output characteristics measured for the correction image formed in response to the instruction and the related information on the stored recording sheet specified, the specified recording sheet Correction means for correcting the color output characteristics;
Transmitting means for transmitting the corrected color output characteristics to the image output device and outputting the printing image based on the image data on the designated recording paper;
The control apparatus characterized by the above-mentioned. An image including an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and a control device that transmits the image data to the image output device An image output method by an output system,
Preliminarily storing associated information associating the color output characteristics for the intermediate image forming medium of the image output apparatus with the color output characteristics for each of the plurality of types of recording paper;
Forming a predetermined correction image on the intermediate image forming medium;
Measuring the color output characteristics of the formed correction image;
Correcting the color output characteristics for the designated recording paper based on the stored related information about the designated recording paper and the measured color output characteristics;
Outputting the print image based on the image data on the designated recording paper using the corrected color output characteristics;
An image output method comprising: An image including an image output device that outputs a print image based on image data onto a designated recording paper from among a plurality of types of recording paper, and a control device that transmits the image data to the image output device An image output method by an output system,
Storing, in advance, related information associating the color output characteristics for a predetermined type of the recording paper among the plurality of types of recording paper and the color output characteristics for each of the other types of recording paper;
Forming a predetermined correction image on the predetermined type of recording paper;
Measuring the color output characteristics of the formed correction image;
Correcting the color output characteristics for the designated recording paper based on the stored related information about the designated recording paper and the measured color output characteristics;
Outputting the print image based on the image data on the designated recording paper using the corrected color output characteristics;
An image output method comprising:   A program for causing a computer to execute the image output method according to claim 11 or 12. A storage medium storing the program according to claim 13 in a computer-readable manner.

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