WO2010137152A1

WO2010137152A1 - Image recording device and method for matching color at image recording device

Info

Publication number: WO2010137152A1
Application number: PCT/JP2009/059793
Authority: WO
Inventors: 一希福井; 和也武田; 理清原
Original assignee: 大日本スクリーン製造株式会社
Priority date: 2009-05-28
Filing date: 2009-05-28
Publication date: 2010-12-02

Abstract

Provided is an inkjet device that can suitably carry out color matching in the case of overprinting. An ink jet device synthesizes a first reading-out image obtained by making a reading–out means read out a first recording image formed at a first recording medium with an additional record scheduling image scheduled to be additionally recorded on the first recording medium. The ink jet device makes a first color matching subject area selected from a scope of the first reading-out image out of the synthesized images, selects a second color matching subject area from a scope of the additional record scheduling image, and thereby carries out the additional recording on the first recording medium. The reading-out means reads out a second recording image formed on a second recording medium to be obtained. The inkjet device calculates a color difference for the first and second color matching subject areas in accordance with a result of such reading-out, and thus corrects the reference table to describe a relationship between a color density value and a discharge amount of ink in accordance with a result of the color difference processing.

Description

Image recording apparatus and color matching method in image recording apparatus

The present invention relates to an ink jet type image recording apparatus, and more particularly to an ink jet type image recording apparatus suitable for, for example, printing on a printing paper on which a background or the like has already been printed.

In general, when creating a printed material, color calibration (calibration) is performed so that the intended color expression is realized on the printed material, or color reproducibility is maintained when creating multiple copies of the same content. It is essential that The specific method of the calibration varies depending on the type of printing apparatus used to produce the printed material. In the case of a printing apparatus that performs printing using ink, the ink supply amount is appropriately controlled. Is required.

For example, in an inkjet printing apparatus (inkjet printing apparatus) that performs image recording by ejecting ink from nozzles while reciprocating the recording head, calibration for matching the colors in the forward direction and the backward direction is efficient. Techniques that can be carried out are already known (see, for example, JP-A-2006-159646).

Also, a printing apparatus having an offset printing mechanism (offset printing apparatus) that can appropriately control ink supply without preparing a reference print for calibration in advance is already known (for example, patents). No. 3781941).

As a method of creating a printed material, a fixed portion such as a background common to all printed materials is printed by an offset printing device (pre-printing), and then a variable portion (variable portion) having different contents depending on the individual printed materials is inkjetted. There is a method of printing (post-printing) with a printing apparatus. In addition, an inkjet printing apparatus may be used when a printed material similar to a printed material prepared in large quantities in advance by an offset printing apparatus is to be reprinted in a small amount later.

When creating a printed matter in such a manner, if there is a portion to be printed with the same color expression in the portion printed by the offset printing device and the portion printed by the inkjet printing device In order to ensure the quality of the printed matter, it is desirable that both are expressed in the same color.

However, since the color gamut of the inkjet printing apparatus is narrower than the color gamut of the offset printing apparatus (the upper limit of the total ink amount is lower than that of the offset printing apparatus), the inkjet printing apparatus uses an offset printing apparatus. In comparison, sufficient color reproducibility may not be obtained.

In general, the profile for an inkjet printing apparatus is different from the profile for an offset printing apparatus. Therefore, print data for an inkjet printing apparatus is created using the profile for an offset printing apparatus, and this is used for inkjet printing. Even if printing is performed by the apparatus, an intended output result may not be obtained.

In addition, a method of performing re-RIP for printing in an inkjet printing apparatus based on the printing result of offset printed material is also conceivable, but re-RIP is a time-consuming process and must be performed once with re-RIP. There is a problem that color matching cannot be performed and it takes time.

The present invention has been made in view of the above problems, and provides an ink jet type image recording apparatus that can suitably perform color matching when, for example, image recording is performed on a recording medium on which a background or the like has already been recorded. For the purpose.

In order to solve the above-described problem, according to the first aspect of the present invention, the conveyance timing of a recording medium that includes at least one inkjet head including a plurality of nozzles and is conveyed by a conveyance mechanism along a predetermined conveyance path. The amount of ink corresponding to the value described in the image recording data stored in the storage unit as the color density value of each pixel position of the image to be recorded is stored in the storage unit. By discharging from the nozzles corresponding to the respective pixel positions among the plurality of nozzles according to the description of the reference table that defines the relationship between the color density value and the discharge amount in each of the plurality of nozzles, the recording medium is discharged. An image recording apparatus that performs the image recording includes a display unit that performs various displays related to the image recording apparatus, and a recording medium that passes through the conveyance path. In a state where a reading unit that photoelectrically reads a recording image formed on the recording medium by scanning in opposite directions, a combination processing unit that combines two images, and a selection target image are displayed on the display unit Selection processing means for selecting and designating the first and second color matching target areas from the selection target image, and the first and second color matching target areas based on the read image acquired by the reading means. Color difference calculating means for calculating a color difference, and when the color difference exceeds a predetermined threshold, ink is ejected from the first color matching target area or the second color matching target area among the plurality of nozzles. Table correction means for correcting the reference table for the nozzles performed, and performing additional image recording on the first recording medium on which image recording has been performed in advance. When obtaining the medium, as a preliminary process for color matching between the first and second recording media, the first recording medium is conveyed while the first recording medium is conveyed to the conveying mechanism. A first reading process for causing the reading means to read the first recording image formed on the first reading image, a first reading image obtained by the first reading process, and an additional recording on the first recording medium. The selection processing means in a state in which an image synthesis process for synthesizing the additional recording scheduled image to be performed by the synthesizing means and a synthesized image of the first read image and the additional recording scheduled image are displayed on the display means. The first color matching target area is selected from the range of the first read image in the composite image, and the second color matching target area is selected from the range of the additional recording scheduled image in the composite image. Selection Selection designation processing can be executed in advance, and when the additional image recording is performed after the preliminary processing is executed, the reading unit is configured to perform the additional image recording. The second reading process for reading the second recorded image formed on the second recording medium obtained by the above and the color difference calculating means based on the result of the second reading process, the first and second By performing a color difference calculation process for calculating a color difference for the color matching target area, and a table correction process in which the table correction unit corrects the reference table in accordance with the color difference value calculated by the color difference calculation process. The color matching between the first and second color matching target areas is performed.

In the second aspect, in the image recording apparatus according to the first aspect, the table correction process determines whether the color difference calculated by the color difference calculation process exceeds a predetermined threshold range, and the color difference Is a process of correcting the reference table when the predetermined threshold value is exceeded, and the additional recording process and the first process until the color difference becomes a value within the predetermined threshold range. The color matching between the first and second color matching target areas is performed by repeating the two reading process, the color difference calculation process, and the table correction process.

In the third aspect, the image recording apparatus according to the first or second aspect includes a plurality of storage units that store the recording medium discharged from the conveyance path, and the plurality of storage units can be selectively used. The recording medium discharged from the conveyance path before the color matching is completed and the recording medium on which image recording is performed after the color matching is completed are stored in different storage units. .

According to a fourth aspect, in the image recording apparatus according to any one of the first to third aspects, the additional recording scheduled image synthesized by the image synthesizing process is based on the image recording data for the additional image recording. I got it.

In the fifth aspect, at least one inkjet head having a plurality of nozzles is provided, and each image of the image to be recorded is synchronized with the conveyance timing of the recording medium conveyed by the conveyance mechanism along the predetermined conveyance path. The amount of ink corresponding to the value described in the image recording data stored in the storage means as the color density value of the pixel position is stored in the storage means, and the color density value in each of the plurality of nozzles In an image recording apparatus that records an image on the recording medium by ejecting from a nozzle corresponding to each pixel position among the plurality of nozzles in accordance with a description in a reference table that defines a relationship between the ejection amount and the ejection amount. When the second recording medium is obtained by performing additional image recording on the recorded first recording medium, the first and second recording media In this method, the first recording image formed on the first recording medium on which the image is recorded in advance is read by the reading means provided in the conveyance path of the recording medium in the image recording apparatus. 1 reading step, an image combining step of combining the first read image obtained by the first reading step and an additional recording scheduled image to be additionally recorded on the first recording medium, and the first In a state where a composite image of the read image and the additional recording scheduled image is displayed on a display unit provided in the image recording apparatus, a first color matching target region from the range of the first read image in the composite image And selecting and selecting a second color matching target area from the range of the additional recording scheduled image in the composite image, and the additional recording for the first recording medium. An additional image recording step for performing image recording, a second reading step for reading the second recorded image formed on the second recording medium obtained by the additional image recording step, and a result of the second reading step A color difference calculation step for calculating a color difference for the first and second color matching target regions based on the color difference, and a correction step for correcting the reference table according to the color difference value calculated in the color difference calculation step. I prepared.

According to a sixth aspect, in the color matching method in the image recording apparatus according to the fifth aspect, the table correction step determines whether or not the color difference calculated by the color difference calculation process exceeds a predetermined threshold range. Determining and correcting the reference table when the color difference exceeds the predetermined threshold, and the additional image recording step until the color difference becomes a value within the predetermined threshold range. Then, by repeating the second reading step, the color difference calculating step, and the table correcting step, color matching between the first and second color matching target regions is performed.

According to the first to sixth aspects, when an additional image recording process is to be performed on a recording medium on which an image has already been recorded, the portion to be color-matched in the image obtained after the additional image recording is determined in advance. It can be selected and specified while confirming a composite image of a recorded image and an image to be recorded as an additional image. Then, the image obtained by performing the additional image recording process after the selection is read by the reading unit, the color difference of the color matching target region selected based on the read image is calculated, and the reference table is corrected based on the result. Thus, color matching is realized. In addition, the image is read in the middle of the conveyance path of the recording medium, and the reference table is corrected based on the result. Thereby, efficient and reliable color matching is realized.

1 is a diagram showing a schematic configuration of an image recording apparatus 100 according to an embodiment of the present invention. 1 is a schematic cross-sectional view mainly showing a mechanical configuration of a fixed head type image recording apparatus 100 which is a more specific embodiment of the image recording apparatus 100. FIG. 2 is a perspective view of a main part of the image recording apparatus 100. FIG. It is a figure which illustrates the state which looked at the inkjet head 4H from the discharge surface 4f side. 3 is a block diagram showing a configuration of a controller 8. FIG. It is a figure which shows the virtual component implement | achieved in the main control part 81 with the flow of the data etc. which concern. It is a figure which illustrates the image which shows the process target and process result in the synthetic | combination process means 81a. It is a figure which shows the procedure which concerns on a preliminary process. It is a figure which shows the procedure which concerns on a color matching process.

<Schematic configuration of image recording apparatus>
FIG. 1 is a diagram showing a schematic configuration of an image recording apparatus 100 according to an embodiment of the present invention.

The image recording apparatus 100 performs image recording on a recording medium RM such as printing paper according to the description content of image recording data given in advance (data describing the color density values of pixels constituting the image to be recorded). It is a device that performs recording. More specifically, a plurality of (four in FIG. 1) inkjet heads 4H (41 to 44) apply different colors (for example, four colors of CMYK) for each inkjet head 4H to the recording medium RM. It is an ink jet printer that records an image by discharging. Note that two or more of the plurality of inkjet heads 4H (41 to 44) may eject the same color (for example, white) ink.

In this embodiment, as the recording medium RM, for example, general printing paper (quality paper, etc.) is used. However, the recording medium RM is not limited to this and may be any plastic film or any other material that can accept ink.

The image recording apparatus 100 includes a supply unit 2 that supplies a recording medium RM from a pre-recording storage unit 10 in which a recording medium RM used for image recording is stored, and a recording medium RM through a predetermined transport path (transport path) PA. And an image recording unit 4 that ejects ink from a large number of inkjet nozzles NZ provided at the lower ends of the plurality of inkjet heads 4H (41 to 44) with respect to the recording medium RM passing through the conveyance path. A recording unit RM for discharging the recording medium RM on which image recording has been performed from the conveyance path PA, a post-recording storage unit 6 for storing the recording medium RM discharged by the discharge unit 5, and a recording medium by the image recording unit 4 A scanner 7 that photoelectrically reads an image formed on the RM on the conveyance path PA; a controller 8 that controls the operation of the entire image recording apparatus 100; And a display operation unit 9 consisting of the input operation unit 92 that can execute the input operation in accordance like on the display unit 91 and the manipulation menu to display the operating status and various operation menu at 100, mainly.

FIG. 2 is a schematic cross-sectional view mainly showing a mechanical configuration of the fixed head type image recording apparatus 100 which is a more specific embodiment of the image recording apparatus 100. FIG. 3 is a perspective view of a main part of the image recording apparatus 100. In FIG. 2, an XYZ coordinate system is provided in which the conveyance direction of the recording medium RM is the X-axis positive direction, and the vertically upward direction is the Z-axis positive direction.

In the image recording apparatus 100, all the inkjet heads 4H (the black head 41, the cyan head 42, the magenta head 43, and the yellow head 44) are fixed at predetermined positions, and the recording medium RM is set to each inkjet. Image recording is realized by ejecting ink from a plurality of ink jet nozzles NZ (not shown in FIG. 2) provided in each ink jet head 4H in synchronization with the movement immediately below the head 4H. In the inkjet head 4H, the width direction of the recording medium RM (the Y-axis direction in FIG. 2) with respect to the recording medium RM conveyed immediately below the recording medium RM so that image recording on the entire surface of the recording medium RM is realized. A plurality of inkjet nozzles NZ are arranged so that ink is ejected at regular intervals within the image recording range. As long as the requirements are satisfied, the arrangement of the plurality of inkjet nozzles NZ may be appropriately determined.

In the image recording apparatus 100, the transport mechanism 3 includes a plurality of tables 20 each capable of sucking and holding one recording medium RM through the suction holes 21. The individual recording media RM are sequentially supplied from the pre-recording storage unit 10 to the table 20 by the conveyor 11 provided in the supply unit 2 and are conveyed on the conveyance path PA while being adsorbed and held in the adsorption holes 21. It has become. That is, an adsorption fan 22 is disposed below the transport path of the table 20, and the recording medium RM is adsorbed and held on the table 20 in the adsorption hole 21 by exhausting from the adsorption fan 22.

More specifically, each of the plurality of tables 20 is connected to a chain 23 wound around a pair of sprockets 26 disposed on the side plate 33 with a predetermined distance therebetween. ing. A sprocket 27 is attached to the side of one sprocket 26, and the sprocket 27 is connected to a drive sprocket 28 and a driven sprocket 29 by a chain 30. Since the drive sprocket 28 is provided so as to rotate by driving a motor (not shown), when the motor is driven, the chain 23 wound around the pair of sprockets 26 rotates in response to this, and the guide 25 The table 20 moves while being guided by.

However, the height of the chain 23 is changed in the middle by combining a pair of sprockets 31 and a pair of sprockets 32, and a pair of one sprocket 31 and the sprocket 32 is arranged. The movement of the table 20 is performed by the linear motor mechanism 24 from the location to the location where the other pair of

sprockets

31 and 32 is disposed.

This is to increase the movement accuracy of the table 20 while passing directly under the image recording unit 4 and the scanner 7. Thereby, reduction of an image recording error (discharge position deviation) in the image recording unit 4 and a reading error by the scanner 7 is realized.

In the linear motor mechanism 24, a not-shown mover is provided below the table 20 so as to be detachable from the table 20, and a not-shown stator arranged in the moving direction of the table 20 is used as the mover. The table 20 can be moved by changing the magnetic pole in a state where it is connected to the table 20. At this time, the table 20 moves along the guide 25.

Further, in the image recording apparatus 100, for the purpose of improving the fixability of the ink ejected from each inkjet head 4H, the pre-processing with low visibility (for example, transparent) prior to the execution of ink ejection by each inkjet head 4H. A pretreatment agent discharge head 40 for applying the agent is provided on the upstream side of each inkjet head 4H in the transport path PA. In particular, when image recording is performed on a recording medium RM made of a material with poor ink fixability, it is preferable to apply the pretreatment agent.

Furthermore,

heaters

45, 46, 47, 48, 49 for blowing hot air against the recording medium RM are provided on the downstream sides of the pretreatment agent discharge head 40 and the inkjet heads 4H, respectively. The heater 45 is for preheating, the

heaters

46, 47 and 48 are for intermediate heating, and the heater 49 is for main heating.

Note that the pretreatment agent discharge head 40, each inkjet head 4H, the heaters 45 to 49, and the scanner 7 are driven in a direction (perpendicular to the paper surface in FIG. ) Can be moved. As a result, the pretreatment agent discharge head 40, each ink jet head 4H, the heaters 45 to 49, and the scanner 7 are moved to the image recording position facing the conveyance path PA of the recording medium RM, and the conveyance path PA of the recording medium RM. It is possible to reciprocate between maintenance positions that do not face each other. During the maintenance work, the pretreatment agent discharge head 40, each inkjet head 4H, the heaters 45 to 49, and the scanner 7 are moved to the maintenance position, so that an obstacle is formed on the conveyance path PA of the recording medium RM. Therefore, it is possible to secure a work space when performing maintenance work on the table 20 or the like.

The discharge unit 5 includes a discharge drum 50. The discharge cylinder 50 is separated from the table 20 by winding the recording medium RM around the outer periphery thereof.

Further, in the discharge unit 5, the first discharge path 52 and the second discharge path 53 are switched and used by the discharge path switching mechanism 51 in accordance with a switching instruction from the controller 8. The first discharge path 52 discharges the recording medium RM to the first storage portion 61 (not shown in FIG. 2) of the post-recording storage portion 6. The second discharge path 53 discharges the recording medium RM to the second storage portion 62 (not shown in FIG. 2) of the post-recording storage portion 6. Specifically, the first discharge path 52 and the second discharge path 53 are each configured by a conveyor. Preferably, in the discharge path switching mechanism 51, the first storage unit 61 stores a recording medium RM that has undergone normal (or normal) image recording processing, and the second storage unit 62 stores the others. The recording medium RM is accommodated.

The scanner 7 includes a line-shaped CCD camera, and in response to a reading instruction from the controller 8, the whole or a part (such as a patch) of the image recorded on the recording medium RM is photoelectrically read. Note that reading by the scanner 7 is normally performed on an image recorded in the image recording unit 4, but in the present embodiment, as described later, the scanner does not perform image recording in the image recording unit 4. 7 may be read.

The display operation unit 9 is a so-called touch panel display. That is, an input operation can be performed by an operator touching a predetermined position on the screen in a state where various menus are displayed on the screen. The display operation unit 9 can be said to be a unit in which a display unit 91 and an input operation unit 92 as conceptual components are provided integrally. This aspect is not essential, and for example, a display unit 91 such as a liquid crystal display and an input operation unit 92 including a plurality of key buttons may be provided separately.

<Inkjet head>
Next, the relationship between the arrangement of the inkjet nozzles NZ in the inkjet head 4H and the recording position on the recording medium RM will be described. FIG. 4 is a diagram illustrating a state in which the inkjet head 4H is viewed from the side of the ejection surface 4f (the surface on the lower end side in FIG. 2).

FIG. 4 illustrates an inkjet head 4H having 60 inkjet nozzles NZ1 to NZ60 arranged so that the pitches in the Y-axis direction are equal (indicated by Δ in FIG. 4).

When the recording medium RM passes below the inkjet head (upward in FIG. 4) in the positive direction of the X-axis, more strictly, the recording medium RM is below the inkjet nozzles NZ1 to NZ60 (upward in FIG. 4). When the corresponding regions RE1, RE2, RE3,..., RE60 of the RM pass in the positive direction of the X axis, the ink ejection from each of the inkjet nozzles NZ1 to NZ60 is performed according to the description content of the image recording data. By turning it on / off, image recording on the recording medium RM is realized.

In the ink jet head 4H shown in FIG. 4, these 60 ink jet nozzles NZ are divided into three nozzle units U1 to U3, each having 20 nozzles. The nozzle units U1 to U3 are arranged in a so-called staggered pattern. In addition, in each of the nozzle units U1 to U3, four inkjet nozzles NZ are arranged in the X-axis direction and five in the Y-axis direction while satisfying the above-described relationship regarding the pitch in the Y-axis direction. It becomes. In FIG. 4, an equal pitch state is realized also in the X-axis direction. These are arrangements adopted for the purpose of increasing the recording density in the Y-axis direction, and are not essential in the present embodiment.

<Detailed configuration of controller>
Next, the controller 8 provided in the image recording apparatus 100 will be described in detail. FIG. 5 is a block diagram showing the configuration of the controller 8.

The controller 8 includes a CPU 811, a ROM 812, a RAM 813, and the like, and includes a main control unit 81 that comprehensively controls the entire operation of the image recording apparatus 100 including image recording processing, and a supply control unit 82 that controls the operation of the supply unit 2. And a transport control unit 83 that controls the operation of the transport mechanism 3 and an ink ejection operation in the inkjet head 4H (in the case of the image recording apparatus 100, the ejection operation of the pretreatment agent ejection head 40 is also controlled). ) Discharge control unit 84, discharge control unit 85 for controlling the operation of the discharge unit 5, scanner control unit 87 for controlling the operation of the scanner 7, display operation control unit 89 for controlling the operation of the display operation unit 9, Is provided.

The supply control unit 82, the conveyance control unit 83, the discharge control unit 84, the discharge control unit 85, the scanner control unit 87, and the display operation control unit 89 are provided as dedicated control circuits. As with the main control unit 81, it may be constituted by a CPU, a ROM, a RAM, and the like. Moreover, the aspect which the main control part 81 has the function of these each control part may be sufficient.

In addition, the controller 8 also includes a storage unit 86 composed of, for example, a hard disk. The storage unit 86 stores a program PG that is executed by the CPU 811 to realize various functions in the main control unit 81 and various data related to the operation of the image recording apparatus 100. For example, the image recording data D0 describing the recording content (color density value for each pixel position (XY address) described based on the CMYK color system) about the image to be recorded, or individual inkjet A reference table TB describing the relationship (tone curve) between the color density value of the nozzle NZ and the ink discharge amount, and how to discharge ink when forming pixels of a certain color density value are defined. Data such as SPM (screen pattern memory) data DS is stored in the storage unit 86. The image recording data D0 may be stored in the RAM 813.

<Image recording operation>
A basic image recording operation in the image recording apparatus 100 including the above-described components will be outlined. In the image recording apparatus 100, when the image recording data D0 is given from the outside and stored in the storage unit 86 or the RAM 813, the operator gives an execution instruction according to an execution menu (not shown) displayed on the display operation unit 9. In response to this, the main control unit 81 causes the supply control unit 82, the conveyance control unit 83, the discharge control unit 84, and the discharge control unit 85 to perform the operation of each unit corresponding to a predetermined timing. By controlling it, image recording is realized.

First, the supply control unit 82 operates the supply unit 2 and takes out the recording medium RM from the pre-recording storage unit 10. The supply unit 2 delivers the recording medium RM at a predetermined timing to the table 20 provided in the conveyance mechanism 3 that is driven by the conveyance control unit 83 operating a motor (not shown). The recording medium RM is held by suction on the table 20. The recording medium RM sucked and held on the table is transported on the transport path PA. As described above, the table 20 that holds the recording medium RM is conveyed by the linear motor mechanism 24 immediately below the image recording unit 4 and the scanner 7, and is conveyed by the chain mechanism at other locations.

The ejection control unit 84 ejects ink from the inkjet nozzles NZ according to the description content of the image recording data D0 in accordance with the timing at which the recording medium RM sequentially passes through the plurality of inkjet heads 4H of the image recording unit 4. Let it run. In the image recording data D0, the color density value for each pixel position is described, and the ejection control unit 84 has an amount corresponding to the value described in the image recording data D0 as the color density value at each pixel position. Ink is ejected from the inkjet nozzle NZ corresponding to each pixel position according to the description in the reference table TB for the inkjet nozzle NZ.

More specifically, the ink ejection amount when forming each pixel is determined according to the SPM data DS. Specifically, in the SPM data DS, when performing ejection for forming a pixel having a certain color density value, it is possible to determine all the ejection positions and the number of ejections that should be performed. The color density value is specified. For example, when forming a pixel having a low color density value in the SPM data DS, a small drop is performed to drop only once at the same pixel position in accordance with the discharge position pattern for the low color density value. When forming a pixel, a medium drop is performed twice in accordance with a discharge position pattern for a medium color density value. When forming a pixel with a high color density value, the discharge position pattern for a high color density value is used. It is stipulated to perform a large drop that drops three times. The discharge controller 84 controls the inkjet head 4H according to the SPM data DS.

When the recording medium RM is transported in this manner and the ink discharge for all the pixels proceeds in sequence, the leading end of the recording medium RM reaches the scanner 7. If necessary, the scanner control unit 87 controls the scanner 7 to sequentially read the recording medium RM from the tip portion. The read image data obtained by such reading is given to the main control unit 81, held in the RAM 813 or the storage unit 86, and subjected to predetermined processing.

When all the image recording in the image recording unit 4 and the reading operation by the scanner 7 are completed and the recording medium RM reaches the discharge cylinder 50, the discharge control unit 85 operates each part of the discharge cylinder 50 and the other discharge units 5, The recording medium RM is separated from the table 20, and the recording medium RM is discharged to the storage unit 6 after recording.

The above is the standard image recording operation flow for the recording medium RM. When image recording is performed on a large number of recording media RM, the recording media RM are continuously supplied from the supply unit 2, and the table 20 holding the recording media RM reaches the corresponding position in the subsequent processing. It is executed every time.

<Components related to color matching processing>
Furthermore, in the image recording apparatus 100 according to the present embodiment, an additional image recording process (additional recording process) is performed on a prerecorded recording medium (first recording medium) RM1 on which an image has been recorded in advance. In this case, a color matching process for matching the color of the additionally recorded image with the color of the predetermined image formed on the prerecorded recording medium RM1 can be performed. For example, a suitable example is a case where post-printing is performed by the image recording apparatus 100 on printing paper that has been partially pre-printed by an offset printing machine or the like.

In the image recording apparatus 100, the CPU 811 executes the program PG, so that the main control unit 81 has a composition processing unit 81a and a selection processing unit as virtual components that function when the color matching is realized. 81b, a color difference calculation unit 81c, and a table correction unit 81d are realized. FIG. 6 is a diagram showing these components together with the flow of related data and the like.

The synthesizing processing unit 81a performs processing for synthesizing two pieces of image data and causing the display operation unit 9 to display them as one synthesized image. Here, the image data representing the composite image is referred to as composite image data DC. Note that the composite image data DC does not necessarily have to be described as one image data, and is described so that the method of superimposing the two image data and the two image data when displayed on the display operation unit 9 can be specified. May be.

When color matching is performed in the additional recording process, as a preliminary process prior to this, first read image data D1 obtained by reading an image recorded on the prerecorded recording medium RM1 with the scanner 7, A composite image is generated based on the additional recording data DA, which is image recording data describing the image recording contents in the additional recording process. Note that the data flow indicated by the alternate long and short dash line in FIG. 6 relates to the preliminary processing, and the data flow indicated by the solid line is directly related to the color matching processing.

FIG. 7 is a diagram exemplifying an image showing a processing target and a processing result in the synthesis processing unit 81a. FIG. 7A is an example of the first read image IM1 expressed by the first read image data D1. FIG. 7B is an example of the additional image IM2 expressed by the additional recording data DA. That is, the additional image IM2 is an image that is actually formed in the image recording apparatus 100 during the additional recording process. FIG. 7C is an example of the composite image IM3 expressed by the composite image data DC.

The selection processing means 81b allows the operator to select and specify two color matching target areas from the target image in a state where the target image is displayed on the display operation unit 9, and the target area data DP describing the specification result. Is responsible for processing to generate (selection and designation processing). Here, the two color matching target areas are determined by the operator pointing each of the two areas to be color-matched one by one from the target image. For example, in the state where the composite image IM3 as shown in FIG. 7C is displayed on the display operation unit 9, the operator operates an instruction index such as a cursor or a pointer displayed on the display operation unit 9 at the same time, for example. Selected by. More specifically, a range of pixels having substantially the same color density value as the pixel designated by the instruction index (belonging to a predetermined color density value range with reference to the color density value at the designated point) is the color matching target area. It is determined. When the color matching target area is determined, the result is held in the RAM 813 or the storage unit 86 as target area data DP.

When color matching is performed, the selection specifying process is performed on the composite image IM3 as a preliminary process prior to the color matching process. In this case, as shown in FIG. 7C, the first color matching target area P1 is selected from a range derived from the first read image IM1, and the second color matching target area P2 is derived from the additional image IM2. Selected from a range. In FIG. 7, the location of the logo mark “ABC” in the range derived from the first read image IM1 is selected as the first color matching target region P1, and the logo mark “ABC” in the range derived from the additional image IM2 This example illustrates a case where the part is selected as the second color matching target region P2. This is a state in which pixels constituting each logo mark having substantially the same color density value as the corresponding location are specified as the color matching target region as a result of selection instruction of any location of each logo mark Pointing. In addition, the color matching target area is selected with the same color reproducibility as the logo “ABC” already formed on the prerecorded recording medium RM1, and the image recording of the logo “ABC” is performed in the additional recording process. This corresponds to the case where it is desired to realize

That is, in the present embodiment, prior to performing the additional image recording, the image to be created by the additional recording is virtually displayed on the display operation unit 9 in the form of a composite image of the pre-recorded image and the image to be additionally recorded. In addition, it is possible to designate a portion where the color is to be matched in the image obtained after the additional recording while confirming the composite image. As a result, the operator can easily and reliably specify the location where color matching is desired. In addition, since the information on the color matching target area is held as the target area data DP, it is not necessary to sequentially specify the color matching target area when the color matching process is repeated, and the color matching process becomes efficient. Is done.

The color difference calculation means 81c is responsible for processing to obtain color density values for two color matching target areas selected by the selection / designation process from the image data representing the target image, and to calculate these color differences ΔE. Here, the color difference ΔE is expressed by the following formula 1 when the color density values of the two color matching target areas are (L1, a1, b1) and (L2, a2, b2) in the Lab color system, respectively. Is a value calculated by. When a plurality of pixels having different color density values exist in the color matching target area, an average value of these color density values is used for calculation.

ΔE = {(L2-L1) ² + (a2-a1) ² + (b2-b1) ² } ^1/2 (Formula 1)
The calculated value of the color difference ΔE is held in the RAM 813 or the storage unit 86 as the color difference data DD.

When color matching is performed in the additional recording process, the scanner 7 immediately reads the second recording medium (recording medium after additional recording) RM2 obtained by the additional recording process on the transport path PA, so that the second read image is obtained. Data D2 is acquired. The color difference calculating unit 81c acquires color density values for pixels corresponding to the first color matching target area P1 and the second color matching target area P2 in the second read image data D2, and calculates the color difference ΔE. . In such a case, the image data described in the RGB color system obtained by the scanner 7 is converted into image data in the Lab color system in accordance with the ICC profile in the scanner 7 and then used for processing by the color difference calculation means 81c. Is done.

The table correcting unit 81d compares the value of the color difference ΔE described in the color difference data DD with a predetermined threshold value, and if the value of the color difference ΔE exceeds the threshold value, the plurality of inkjet nozzles provided in the inkjet head 4H. Of the NZ, it is responsible for correcting the reference table TB for the inkjet nozzle NZ that has ejected ink for the second color matching target area during the additional recording process.

As long as the correction of the reference table TB is performed so that the value of the color difference ΔE becomes smaller when the next printing based on the same additional recording data is performed, the specific mode is not limited. For example, the ejection amount corresponding to each color density value is corrected in accordance with the magnitude relationship of the L, a, and b parameters and the degree of difference between (L1, a1, b1) and (L2, a2, b2). A mode in which the degree is appropriately determined may be used, or a mode in which the discharge amount is uniformly adjusted regardless of the degree of difference between the parameters.

When the first color matching target area P1 and the second color matching target area P2 are set with the intention of color matching, the second color matching target area P2 is set in the image recording process performed immediately before. With respect to the inkjet nozzle NZ that has ejected the ink, the ejection amount described in the reference table TB is corrected.

<Color matching procedure>
Next, a procedure of color matching processing when performing additional recording processing on the prerecorded recording medium RM1 will be described. The color matching process is roughly divided into a preliminary process for specifying a portion (color matching target area) to be color matching and a color matching process (additional recording process and correction process based on the result).

FIG. 8 is a diagram showing a procedure related to the preliminary processing. First, the prerecorded recording medium RM1 to be subjected to the additional recording process is accommodated in advance in the pre-recording storage unit 10 (step S1). Thereafter, when the operator gives an execution instruction for preliminary processing according to an execution menu (not shown) displayed on the display operation unit 9 (step S2), the main control unit 81 responds to the normal recording operation described above. Similarly to the case of executing, the supply control unit 82 and the conveyance control unit 83 cause the supply and conveyance of the pre-recorded recording medium RM1 to be executed (step S3).

That is, the supply control unit 82 operates the supply unit 2 and takes out the pre-recorded recording medium RM1 from the pre-recording storage unit 10. The supply unit 2 delivers the pre-recorded recording medium RM1 to the table 20 provided in the transport mechanism 3 that is driven by the transport control unit 83 operating a motor (not shown) at a predetermined timing. The prerecorded recording medium RM1 is held by suction on the table 20. The prerecorded recording medium RM1 sucked and held on the table 20 is transported on the transport path PA. Also in this case, the table 20 holding the pre-recorded recording medium RM1 is transported by the linear motor mechanism 24 immediately below the image recording unit 4 and the scanner 7, and is transported by the chain mechanism at other locations.

However, in the preliminary processing, the image recording unit 4 does not record an image, and the prerecorded recording medium RM1 is conveyed to the scanner 7. The scanner control unit 87 controls the scanner 7, and when the leading end of the prerecorded recording medium RM1 reaches the scanner 7, the prerecorded recording medium RM1 is sequentially read from the leading end (step S4). . The first read image data D1 obtained by such reading is given to the main control unit 81 and held in the RAM 813 or the storage unit 86.

The pre-recorded recording medium RM1 that has been read by the scanner 7 is separated from the table 20 by the discharge control unit 85 operating each part of the discharge cylinder 50 and the discharge unit 5, and is discharged to the storage unit 6 after recording. (Step S5). The prerecorded recording medium RM1 is preferably accommodated in the second accommodating portion 62 by causing the ejection path switching mechanism 51 to use the second ejection path 53. This is because only the post-addition recording medium RM2 that has been normally recorded by the subsequent color matching process is accommodated in the first accommodating portion 61.

On the other hand, in the image recording apparatus 100, additional recording data DA, which is image recording data D0 used for additional recording, is given from the outside and stored in advance in the storage unit 86 or the RAM 813. When the first read image data D1 is obtained as described above, the composition processing unit 81a generates the composite image data DC from the first read image data D1 and the additional recording data DA, and the composite image data DC is displayed on the display operation unit 9. The image IM3 is displayed (step S6).

When the composite image IM3 is displayed on the display operation unit 9, the color matching target area can be selected. The operator selects, as a first color matching target area P1, a region to be used as a color matching reference from the range derived from the first read image IM1 in the composite image IM3, and from the range derived from the additional image IM2, A region desired to be matched is selected as the second color matching target region P2 (step S7). Based on these selection results, target area data DP is generated. This completes the preliminary processing.

FIG. 9 is a diagram showing a procedure related to the color matching process. When the operator gives an instruction to execute the color matching process according to an execution menu (not shown) displayed on the display operation unit 9 after the above preliminary process is completed (step S11), the main control unit 81 responds to the instruction. As in the case of executing the normal recording operation described above, the supply control unit 82 and the conveyance control unit 83 cause the supply and conveyance of the prerecorded recording medium RM1 to be executed (step S12), and the ejection control unit 84. In response to this, an additional recording process corresponding to the description content of the additional recording data DA is executed (step S13).

That is, the ejection control unit 84 starts from the inkjet nozzle NZ corresponding to the description content of the additional recording data DA in accordance with the timing at which the prerecorded recording medium RM1 sequentially passes through the plurality of inkjet heads 4H of the image recording unit 4. The ink is discharged. In the additional recording data DA, the color density value for each pixel position is described, and the ejection control unit 84 has an amount corresponding to the value described in the additional recording data DA as the color density value at each pixel position. Ink is ejected from the inkjet nozzle NZ corresponding to each pixel position according to the description in the reference table TB for the inkjet nozzle NZ.

In this way, after the pre-recorded recording medium RM1 is being transported, the ink ejection for all the pixels proceeds in sequence, thereby generating the post-addition recording medium RM2. Eventually, the leading end of the recording medium RM2 after the additional recording reaches the scanner 7. The scanner control unit 87 controls the scanner 7 to read the recording medium RM2 after additional recording sequentially from the leading end when the leading end of the recording medium RM2 after additional recording reaches the scanner 7 (step S14). . The second read image data D2 obtained by such reading is given to the main control unit 81 and held in the RAM 813 or the storage unit 86.

The additional post-recording recording medium RM2 that has been read by the scanner 7 is separated from the table 20 by the ejection control unit 85 operating each part of the ejection cylinder 50 and the other ejection unit 5, and is ejected to the post-recording storage unit 6. (Step S15). Preferably, the post-addition recording medium RM2 is accommodated in the second accommodating portion 62 by causing the ejection path switching mechanism 51 to use the second ejection path 53.

On the other hand, when the second read image data D2 is obtained, the color difference calculation means 81c causes the color density for the first color matching target area P1 and the second color matching target area P2 described in the target area data DP. A value is acquired from the second read image data D2, and a color difference ΔE is calculated according to Equation 1 (step S16). When pixels having different color density values exist in each region, the average value thereof is used for calculation. The calculation result is given to the main control unit 81 as color difference data DD, and held in the RAM 813 or the storage unit 86.

When the color difference data DD is obtained, the table correction unit 81d determines whether or not the value of the color difference ΔE described in the color difference data DD is within a predetermined threshold range (step S17). When the value of the color difference ΔE exceeds the predetermined threshold range (NO in step S17), the table correction unit 81d ejects ink to the area designated as the second color matching target area P2. The reference table TB for NZ is corrected (step S18). Subsequently, based on the corrected reference table TB, the processes after step S12 are repeated to perform additional recording processing again.

As a result of repeating these processes, when the value of the color difference ΔE described in the color difference data DD falls within the threshold range (YES in step S17), the first color matching target area P1 and the second color matching are set. Color matching with the target area P2 can be realized. Thereafter, by using the reference table TB used at this time as it is, image recording in a state of good color matching is realized, so that image recording is repeatedly executed as many times as necessary (step). S19).

When the post-addition recording medium RM2 generated until ΔE falls within the threshold range is stored in the second storage section 62 from the second discharge path 53, the table correction unit 81d. In response to the value of the color difference ΔE falling within the threshold value range, the discharge path switching mechanism 51 causes the first discharge path 52 to be used, so that the post-recording recording medium RM2 has the first recording medium RM2. It is accommodated in the accommodating part 61.

As described above, in the ink jet image recording apparatus according to the present embodiment, when an additional recording process is to be performed on a recording medium on which an image has already been recorded, prior to this, additional recording is performed. The image to be created is virtually realized in the display operation unit in the form of a composite image of the pre-recorded image and the image to be additionally recorded, and the portion where the color is to be matched in the image obtained after the additional recording is combined. It can be specified while checking the image. When the image obtained by performing the additional recording process after the selection is read by a scanner and the color difference of the selected color matching target area is calculated, and the color difference exceeds a predetermined threshold, the image is recorded. The color matching is realized by repeating the process of correcting the reference table describing the relationship between the color density value used for the ink discharge amount and the ink discharge amount until the color difference becomes equal to or less than the threshold value. In addition, the image is read in the middle of the recording medium conveyance path, the reference table is corrected based on the result, and the next image is recorded. That is, according to the ink jet type image recording apparatus according to the present embodiment, when image recording is additionally performed on a recording medium on which an image has already been formed, such as when post-printing is performed on preprinted printing paper. In addition, efficient and reliable color matching between the image formed earlier and the image formed later is realized.

<Modification>
In the above-described embodiment, when the reference table TB is corrected for a certain inkjet nozzle NZ, the corrected reference table TB is also displayed at the ejection position other than the color matching target area for the inkjet nozzle NZ. Ink ejection based on this will be executed. Instead, the reference table TB before and after correction is held in the RAM 813 or the like, and only the ink discharge to the color matching target area is performed using the corrected reference table TB, and the part not included in the color matching target area For this, the reference table TB before correction may be used.

In the above-described embodiment, the description has been made mainly for an ink jet type image recording apparatus having a fixed head, but the same color matching processing is also realized in an image recording apparatus of a type in which an inkjet head is movable. Is possible.

Claims

A color density value at each pixel position of an image to be recorded, having at least one ink jet head having a plurality of nozzles and synchronized with the transport timing of the recording medium transported along a predetermined transport path by the transport mechanism The relationship between the color density value and the discharge amount of each of the plurality of nozzles stored in the storage unit is an amount of ink corresponding to the value described in the image recording data stored in the storage unit as An image recording apparatus for recording an image on the recording medium by ejecting from a nozzle corresponding to each pixel position among the plurality of nozzles according to a description of a reference table defining:
Display means for performing various displays relating to the image recording apparatus;
Reading means for photoelectrically reading a recorded image formed on the recording medium by relatively scanning the recording medium passing through the conveyance path;
A composition processing means for compositing two images;
Selection processing means for selecting and designating the first and second color matching target areas from the selection target image in a state where the selection target image is displayed on the display means;
Color difference calculating means for calculating a color difference between the first and second color matching target areas based on a read image acquired by the reading means;
When the color difference exceeds a predetermined threshold value, the reference table for nozzles that have ejected ink to the first color matching target region or the second color matching target region among the plurality of nozzles. Table correction means for correcting;
Further comprising
When obtaining a second recording medium by performing additional image recording on the first recording medium on which image recording has been performed in advance, a preliminary for color matching between the first and second recording media As a process
A first reading process for causing the reading unit to read a first recorded image formed on the first recording medium while conveying the first recording medium to the conveying mechanism;
An image synthesis process for synthesizing the first read image obtained by the first reading process and an additional recording scheduled image to be additionally recorded on the first recording medium by the synthesis unit;
In a state where a composite image of the first read image and the additional recording scheduled image is displayed on the display means, the selection processing means causes the first read image from the range of the first read image in the composite image. And a selection specifying process for selecting the second color matching target area from the range of the additional recording scheduled image among the combined images, and
Can be executed in advance,
After the preliminary processing is performed and the additional image recording is performed,
A second reading process in which the reading unit reads a second recorded image formed on the second recording medium obtained by the additional image recording;
A color difference calculation process in which the color difference calculation means calculates a color difference for the first and second color matching target areas based on a result of the second reading process;
A table correction process in which the table correction unit corrects the reference table in accordance with a color difference value calculated by the color difference calculation process;
To perform color matching between the first and second color matching target areas,
An image recording apparatus.
The image recording apparatus according to claim 1,
The table correction process determines whether or not the color difference calculated by the color difference calculation process exceeds a predetermined threshold range, and when the color difference exceeds the predetermined threshold value, the reference table Is a process for correcting
By repeating the additional image recording process, the second reading process, the color difference calculation process, and the table correction process until the color difference reaches a value within the predetermined threshold range, Color matching between the first and second color matching target areas is performed.
An image recording apparatus.
The image recording apparatus according to claim 1 or 2, wherein
A plurality of storage units for storing the recording medium discharged from the transport path are provided, the plurality of storage units are selectively usable, and are discharged from the transport path before the color matching is completed. A recording medium and a recording medium on which image recording has been performed after the color matching is completed are accommodated in different accommodating portions.
An image recording apparatus.
The image recording apparatus according to claim 1, wherein:
The image recording apparatus, wherein the additional recording scheduled image synthesized by the image synthesis process is acquired from the image recording data for the additional image recording.
A color density value at each pixel position of an image to be recorded, having at least one ink jet head having a plurality of nozzles and synchronized with the transport timing of the recording medium transported along a predetermined transport path by the transport mechanism The relationship between the color density value and the discharge amount of each of the plurality of nozzles stored in the storage unit is an amount of ink corresponding to the value described in the image recording data stored in the storage unit as In the image recording apparatus that records an image on the recording medium by ejecting from the nozzle corresponding to each pixel position among the plurality of nozzles according to the description of the reference table that defines When a second recording medium is obtained by performing additional image recording on the recording medium, the color between the first and second recording media A way to do so,
A first reading step of reading a first recorded image formed on a first recording medium on which image recording has been performed in advance by reading means provided in a conveyance path of the recording medium in the image recording apparatus;
An image synthesis step of synthesizing the first read image obtained by the first reading step and an additional recording scheduled image to be additionally recorded on the first recording medium;
In a state where a composite image of the first read image and the additional recording scheduled image is displayed on a display unit provided in the image recording apparatus, a first color is selected from the range of the first read image in the composite image. A selection specifying step of selecting a matching target area and selecting a second color matching target area from the range of the additional recording scheduled image in the composite image;
An additional image recording step for performing the additional image recording on the first recording medium;
A second reading step of reading the second recorded image formed on the second recording medium obtained by the additional image recording step;
A color difference calculating step of calculating a color difference for the first and second color matching target areas based on a result of the second reading step;
A correction step of correcting the reference table in accordance with the color difference value calculated in the color difference calculation step;
A color matching method in an image recording apparatus.
A color matching method in the image recording apparatus according to claim 5,
The table correction step determines whether or not the color difference calculated by the color difference calculation process exceeds a predetermined threshold range, and when the color difference exceeds the predetermined threshold value, the reference table Is a process of correcting
The additional image recording step, the second reading step, the color difference calculating step, and the table correcting step are repeated until the color difference reaches a value within the predetermined threshold range. And color matching between the second color matching target area and
A color matching method in an image recording apparatus.