JP2001053976A - Multi-color reproduction color correction device and multi-color proofreading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a proof sheet of faithful color reproduction from the raster image data including process four colors and a specific color by performing a multilcolor separation after reading the chromaticity value of the specific color that is previously set when the input image data include a specific color component and performing the conversion to process colors when the input image data includes no specific color component. SOLUTION: A multi-color proofreading device 1 performs the color correction processing of the raster image data in every component color by using a multi-color reproduction color correction device 10 to produce the gradation data of a raster form in every component color of the device 1 and produces a color printed matter with a print engine 30. The 1st and 2nd process color transformation means 13 and 14 perform the color transformation of process colors about the pixels of the raster image data having zero specific color components of the gradation value. Then a multicolor separation means 15 performs the multicolor separation of the pixels of the raster image data having non-zero specific color components of the gradation value according to the chromaticity value of 100% specific color that is previously set in a specific color chromaticity value memory 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to C (cyan), M
Process 4 for (magenta), Y (yellow), and K (black)
Using a multi-color printer that reproduces a color with one or more auxiliary colors other than the color, a color proof of plate making data created for the purpose of printing using a so-called special color ink other than the process color is obtained. The present invention relates to a color proofing device and a multi-color reproduction color correcting device.

[0002]

2. Description of the Related Art Generally, in the printing industry, a proof print is submitted in order to obtain the confirmation of a print orderer regarding color reproduction and design appearance before printing on a printing press. Nowadays, a method of producing a proof with an output of a digital color printer (DDCP) of an ink jet method or a sublimation transfer method without producing a proof with a proof press is being adopted between a printing company and a print orderer. .

[0003] In digital color printers and proofs or main presses, ie offset printing or gravure printing,
The color reproduction differs depending on the hue of each color of the process colors used, the paper, the coloring mechanism, and the like. Therefore, appropriate color matching processing is performed on the original plate making data to create output data for DDCP. , Is usually used.

[0004]

However, in the field of packaging printing, conventionally, for the purpose of stabilizing reproduced colors,
Or, it is common to use an ink called a special color other than the process color in order to appeal to the consumer of the product. In general, high-brightness and high-saturation colors are often used as spot colors, and there has been a problem that color reproduction cannot be faithfully performed with DDCP that reproduces colors using CMYK process colors. Therefore, recently, in order to expand the color reproduction range, multicolor DDCP using five or more color materials using auxiliary colors such as green and orange in addition to the process color has come to market.
A proofing apparatus for spot colors, which efficiently obtains proof prints with faithful color reproduction by using multicolor DDCP for plate making data containing colors to be reproduced as spot colors, has not yet been established.

The present invention has been made in view of such problems, and has been obtained by processing plate making data including a color to be reproduced as a special color using a multi-color DDCP with a RIP device or the like. It is an object of the present invention to realize a multi-color reproduction color correction apparatus for obtaining a proof print with faithful color reproduction from raster image data including four process colors and special colors.

[0006]

According to the present invention, raster image data including special colors other than the four process colors is input, and C (cyan), M (magenta), and Y (yellow) are input. , K (black) process, and a color correction device for a multi-color proofing device that reproduces one or more auxiliary colors as component colors in a color correcting device for a multicolor proof device, wherein the input image data is printed and reproduced in process colors. In the case of a color, a process color conversion means for performing color correction so as to be reproducible with the four colors of the process of the multicolor proofing apparatus, and a chromaticity value designated by measuring a color sample in advance and receiving a designated chromaticity value, Multicolor separation means for performing multicolor separation into component colors including auxiliary colors of a multicolor proofing device, when the input image data includes a special color component, Read the chromaticity value of the spot color Then, the multi-color separation unit is activated to perform multi-color separation, and if not, the process color conversion unit is activated and converted to a process color, so that the input raster image data The gist of the present invention is to configure a multicolor reproduction color correction device that creates separation data for each component color of the color proofing device. Further, the gist of the present invention is that a multicolor print engine is added to the multicolor reproduction color correction device to constitute a multicolor proofing device.

In the multicolor reproduction color correcting device or the multicolor proofing device, the color of each pixel of the input raster image data is converted into the process color of the proofing machine by the first process color conversion means, The image is separated into color components including auxiliary colors by the separation. CMYK of process ink and C'M'K 'of proofing device
Since Y 'has the same color but different hue and saturation, a first process color conversion means for converting a CMYK process color into a C'M'K'Y' process color is required. In the present invention, it is assumed that the input raster image data does not have a portion printed in a special color multiplied by another color. Therefore, it is extremely rational to separately reproduce a portion with a special color component by multi-color separation using an auxiliary color component, separately into a case with a special color component and a case without a special color component.

Further, according to the present invention, in the multi-color reproduction color correcting device, before or after the process of the process color conversion means, it is determined that the color cannot be reproduced by the process color, and the color that cannot be reproduced by the process color is determined. If it is determined that the second process color conversion means for estimating the chromaticity value of the color and activating the multicolor separation means is provided.

[0009] Even in a color reproduced only by the process color of the printing ink, if the color saturation is high, it may not be possible to reproduce the color only by the process color of the proofing device. With respect to such colors, faithful color reproduction can be obtained by performing reproduction including auxiliary colors by the second process color conversion means.

[0010] A second aspect of the present invention is a multi-color reproduction color correcting apparatus in which a process color used in a multi-color reproduction apparatus or a printing apparatus matches a process color of original input raster image data. Input raster image including multicolor separation means for receiving a designated chromaticity value by measuring a color sample in advance and performing multicolor separation between a process color to be used and an auxiliary color, and including a special color other than the four process colors If the data contains the component of the special color, the chromaticity value of the special color set in advance is read, and the multicolor separation unit is activated to perform multicolor separation between the process color and the auxiliary color. Otherwise, by using the raster image data of the four process colors as it is, the separated raster data for each component color used in the multi-color reproducing apparatus or the printing method can be obtained from the input raster image data. And summarized in that constitute the multi-color reproduction for color correction device to create a data.

When the process color used in the multicolor reproducing device or the printing device matches the process color of the original plate making data, the color correcting device for multicolor reproduction can be constituted by omitting the process color converting means.

[0012]

FIG. 1 is an overall view of a multicolor proofing apparatus 1 according to one embodiment of the present invention. Reference numeral 10 denotes a multi-color reproduction color correction device, which includes a special color chromaticity value separation value memory 12, a first process color conversion unit 13, and a second process color conversion unit 1.
4, a multi-color separation unit 15, a control unit 16, a process color conversion LUT group 17, and a multi-color separation LUT group 18. Multi-color reproduction color correction device 10 RIP
The data converted into raster image data for each component color by a device or the like is input, color correction processing is internally performed, and tone data in a raster format for each component color of the multicolor proofing device is created, and the print engine 30 is executed. Pass to. The print engine 30 performs necessary screening processing and drives the print head to create a multi-color print. Reference numeral 40 denotes an external storage device attached to the multi-color reproduction color correction device, and temporarily stores image data after the RIP processing. An input device 50 sets a chromaticity value of a special color sample obtained by a colorimeter or the like. The control unit 16 controls the entire apparatus 10, appropriately operates the various conversion units 13, 14, and 15, and performs necessary control so as to correctly synthesize multicolor separation data that can be finally output to the print engine 30.

Hereinafter, in the description of the embodiment, the print engine 30 uses process colors C ', M', Y ', K' and G
(Green) and six colors of O (orange) are reproduced.

The input raster image data to be supplied to the multi-color reproduction color correction device 10 is obtained by developing the plate making data such as the EPS file format into the raster image data by the RIP device. Since the underlay plate making data is data created for reproduction by printing, the color information is naturally described in the colors used for printing. Therefore, when the printing colors are the process colors Y, M, C, and K and the special colors 1 and 2, the description of the color of the plate making data is described in only these 6 colors. The image data has the color information of these six colors. still,
Normally, the RIP device outputs monochromatic raster format gradation data for each color plate for the number of colors, but the input raster image data to be supplied to the multicolor reproduction color correction device 10 has a format in which each color gradation value is arranged for each pixel. Data may be used. In any of the formats, the color value of a certain pixel of the input raster image data is set as a vector value, and a gradation value = (C, M, Y,
K, special 1 and special 2). Each vector component is set to a numerical value (halftone dot%) of 0 to 100 where solid is 100 and white is 0.

The first process color conversion means 13 converts the color to be reproduced by the process color CMYK of the printing into the process color C ', M', Y ', K' of the multicolor printer faithfully. A process for making a correction is performed. Even though the printing process color CMYK and the multicolor printer process color C'M'Y'K 'are the same, the hues and color densities are somewhat different, so the CMYK values of the input raster image data are directly used as the printer's C'M' Assuming a Y'K 'value,
It does not result in faithful color reproduction. Therefore, for a pixel having a special color component of a gradation value of zero in the image data after RIP, color conversion for process color is performed.

In the process color conversion, CMYK → C'M'Y'K 'conversion is performed.
(Reference 1). Document 1 has a three-dimensional LUT which is a correspondence table of a combination (lattice point) of a specific value of CMY (lattice point) and a C'M'Y 'value corresponding to the combination. CMY → C'M'Y' A three-dimensional converter for conversion, a one-dimensional table for K → K ′, and K ′
Three one-dimensional tables for outputting each correction amount of C'M'Y ',
And a color correction device for converting CMYK → C′M′Y′K ′. A group of these three types of five LUTs is a process color conversion LUT group 17. still,
Reference 1 describes that the contents of these tables are obtained by trial and error by repeating experiments.

If there is a color component of C'M'Y'K 'obtained as a result of the process color conversion, which has a negative value or a value exceeding 100, C'M'Y'K' Because it is a color that can not be reproduced,
By the operation of the second process color conversion means 14, multicolor separation in which the auxiliary colors O and G are added is performed. In order to perform multi-color separation, a target chromaticity value must be given to the multi-color separation means, so it is necessary to estimate the chromaticity value of the original CMY value.

Pixels in the input image data where the special color component of the gradation value is not zero are portions to be printed using the special color. For such a portion (pixel), the chromaticity value of the special color 100% is set in advance in the special color chromaticity value memory 12 before the processing. Color separation is performed. In the present embodiment, it is assumed that a portion to be printed in a special color does not have a crossover with another color.

In this embodiment, CIE is used as a display space for chromaticity.
(International Commission on Illumination) CIELAB (CIE1976L * a)
* b * display) space is used. Therefore, the measured value of the colorimeter is (L *,
a *, b *). The color difference ΔE representing the closeness of the two colors C1 and C2 is C1 = (L1, a1, b1), C2
ΔE = √ ((L1-L2) ** 2+ (a1-a2) ** 2+ when = (L2, a2, b2)
(B1-b2) ** 2). Where A ** 2 is the square of A and √B is B
Means the square root of

FIG. 2 is a flowchart showing a procedure for preparing the apparatus according to the present embodiment. Multi-color reproduction color correction device 10
In order to use the LUT group, a process color conversion LUT group 17 and a multi-color separation LUT group 18 must be prepared.

First, in step S10, a process color conversion LUT group 17 is created. It is reasonable to construct the most important three-dimensional LUT as follows. CM of printing ink
The gradation value of each color of Y is set to a predetermined number of steps, for example, 10 steps, and all combinations of the gradation values of three colors (CMY
Lattice point) A table in which a color chart in which 1000 kinds of color pieces are arranged is printed and measured by a colorimeter to determine a chromaticity value (Lab) corresponding to each CMY lattice point, and a CMY lattice point is associated with the chromaticity value. (LUT1) is created. Next, a similar color chart is output by the multicolor print engine 30 and similarly measured by a colorimeter, and the chromaticity value (La) corresponding to each C'M'Y 'lattice point is measured.
b) is obtained, and a table (LUT2) for associating them is created. If C'M'Y 'corresponding to each CMY grid point is obtained,
Although the three-dimensional LUT in Literature 1 has been obtained, since the chromaticity values linking LUT1 and LUT2 generally do not match, a three-dimensional LUT cannot be obtained directly. However, this can be calculated, for example, as follows.
FIG. 5 shows the relationship among the LUT1 and LUT2, the CMY space, the L * a * b * space, and the C'M'Y 'space. Figure 5 below
The explanation is made with the above relationship in mind.

A certain C'M'Y 'lattice point K'0 and its neighbor,
By taking the difference of the corresponding chromaticity value of the grid point K'C in which only the C 'value has been increased for each of the same components and dividing the difference by the increase in the C' value, the partial differential coefficient (格子 L / ∂C ', ∂a / ∂C', ∂b /
∂C ′) is obtained. Similarly, the adjacent grid point K′M, which has only the M ′ value increased, and the corresponding chromaticity values of the adjacent grid points K′Y, which have only the Y ′ value increased, and K′0 are compared for each component M ′, The partial derivatives (∂L / ∂M ', ∂a / ∂M', ∂b / ∂
M '), (∂L / ∂Y', ∂a / ∂Y ', ∂b / ∂Y').
As a result, the transformation matrix (） Lab) / (∂C'M'Y ') of the mapping from the C'M'Y' space near K'0 to the L * a * b * space becomes
Is required.

(Equation 1) By calculating the inverse matrix of this matrix, the transformation matrix (∂C′M′Y) of the mapping from the Lab space near the chromaticity value P ′ corresponding to the lattice point K′0 to the C′M′Y ′ space is obtained. ') / (∂Lab) is obtained as Equation 2 below.

(Equation 2) From this transformation matrix, the C'M'Y 'value Kn' for the chromaticity P near P '
Is P−P ′ = (ΔL Δa Δb) and an inverse transformation matrix (∂C′M′Y ′)
It is obtained from / (/ Lab) by the following formula. ΔC '= (∂C' / ∂L) ΔL + (∂C '/ ∂a) Δa + (∂C' / ∂b) Δb ΔM '= (∂M' / ∂L) ΔL + (∂M '/ ∂a) aa + (∂M '/ ∂b) bb YY' = (∂Y '/ ∂L) ΔL + (∂Y' / ∂a) Δa + (∂Y '/ ∂b) Δb Kn' = K '0+ (ΔC', ΔM ', ΔY')

Therefore, if the chromaticity corresponding to the CMY lattice point Kn is P and P ′ is located sufficiently close to P,
A point Kn 'on the C'M'Y' space is obtained. FIG. 5 shows this state.

When the above calculation is performed for all the CMY grid points Kn to find the closest chromaticity value P ′ on the LUT 2 with respect to the corresponding chromaticity value P, the C values corresponding to all the CMY grid points are obtained. 'M'Y' is determined, and the three-dimensional LUT of Document 1 is determined. If the color chart is output again by the multi-color print engine using the C'M'Y 'values and fine adjustment is performed, the accuracy is further improved. In this way, once the three-dimensional LUT is determined, the LUT 2 becomes unnecessary. On the other hand, LUT1
Is used for the process color conversion means 14 of FIG.

After the three-dimensional LUT is determined, a one-dimensional table for the correspondence of K → K ′ and three one-dimensional tables for outputting the respective correction amounts of C′M′Y ′ for K ′ are K The difference is determined by trial and error in consideration of the difference in density between K and K ', the color balance of K', and the like.

The above LUT 1 is set in the second process color conversion means 14. The second process color conversion means 14 is C
LUT1 is referred to in order to obtain a chromaticity value from which MY values are to be subjected to multi-color separation.

Next, in step S20, an LU for multicolor separation is set.
Prepare T. Among the six component colors of the multicolor printer, K '
For one of the five colors excluding, one LUT for separation is created from three colors having adjacent hues. Therefore, C'M'O, M'OY ', O
It is necessary to create five types of decomposition LUTs, Y'G, Y'GC ', and GC'M'. Furthermore, C'Y'K 'corresponding to dark green conversion
Also, a separation LUT of three colors is created.

Each decomposing LUT has its three colors (LUT).
For the three colors, the halftone% value of each color (100% solid,
A value that expresses a halftone as a percentage with white as 0%) is set, for example, in 10 steps, and a multi-color target of LUT three-color grid points (1000 kinds), which is a combination of all three colors, is used. The color chart is output by a printer, the chromaticity of the obtained color chart is measured by a colorimeter, and a table in which the measured values are associated with the LUT three-color grid points is created.

The necessary preparation has been completed. Next, the operation of the multicolor proofing apparatus 1 will be described with reference to FIG. In the following description, it is assumed that the plate making data is created with the special color 1 and the special color 2 of the process color and the special color.

First, in step S 30, a special color sample used in the plate making data to be processed is measured by a colorimeter, and the measured value is set in the memory of the special color chromaticity value memory 12. Special colors may be used in more than one color.
Make settings. Thus, the chromaticity value S1 of the special color sample 1
The chromaticity value S2 of the special color sample 2 is set.

Next, at step S40, the special color conversion means 1
By the operation of 5, a multi-color separation value that uses the chromaticities S1 and S2 of the special color sample as designated chromaticity values is obtained. Multicolor separation is shown in the flowchart of FIG. In step S44, a multicolor separation LUT including a three-color lattice point having a chromaticity value with the smallest chromaticity value in the designated chromaticity value S is selected and set as an optimal LUT. Next, step S
At 46, the LUT 3 color separation value for the designated chromaticity value S is determined using the optimal LUT. If there is a three-color grid point having a chromaticity value whose color difference from S is smaller than a predetermined color difference ε in the optimal LUT, it is set as the LUT three-color separation value. If not, some three-color grid points having chromaticity values close to the chromaticity value S of the color sample are selected from the optimal LUT, and the LUT three-color separation value that gives the chromaticity value S is obtained by appropriate interpolation calculation. Ask.

In this interpolation calculation, for example, when a three-dimensional LUT is created, the chromaticity Q ′ of the lattice point of the optimal LUT closest to S is calculated in the same manner as when the C′M′Y ′ decomposition value for P is obtained. Difference S from S−Q ′ = (ΔL Δa Δb) and transformation matrix of mapping from Lab space to optimal three-color space (∂ (optimum three colors)) / (∂Lab)
Can be obtained from This is shown in FIG.
(∂ (optimum three colors)) / (∂Lab) is a transformation matrix (Q) near Q ′ from the chromaticity values of the lattice points Q ′ and some lattice points adjacent to Q ′.
Lab) / (∂ (optimum three colors)) is obtained and the inverse matrix is obtained. In step S48, the color separation values of the designated chromaticity value S can be obtained by setting the separation values of the proofer component colors other than the three optimum colors to zero.

The multicolor separation values of the special color sample obtained in step S42 are stored in the special color separation value memory 12.

Next, at step S50, (C, M, Y,
The raster format gradation data of each of K, special 1 and special 2) is read.

In step S52, the pointer P is set to point to the first pixel of the input image data. Pointer P
(Hereinafter simply referred to as pixel P) is a special color pixel (S54). If so, the multicolor separation value of the corresponding special color set in the special color separation value memory in S42 is used as the separation value of the pixel P. (S90).

If the pixel P is a pixel that reproduces a color with a process color, a process color conversion is performed in step S60. Of the decomposition values of C'M'Y'K 'obtained as a result, 0 to 1
It is checked whether there is any value outside the range of 00 (S62). In such a case, the chromaticity value S of the pixel P is estimated from the CMY of the pixel P in step S68, and multicolor separation is performed. (S70).

In step S80, the obtained separation values of the respective color components of the pixel P are stored in the separation buffer of the proofreading machine.
Thereafter, it is determined whether or not the processing has been performed for all the pixels (S82). If the processing has not been completed, the pointer P is set to the next pixel (S84), and the process returns to S54 to repeat the processing for each pixel.

When the above processing is completed for all the pixels, the separation data of the component colors of the proofing machine can be obtained from the separation buffer, and transferred to the print engine. can get.

The print engine 30 converts the received decomposed image data into data for directly driving the print head. The process performed here is a process of modulating the tone value of a pixel into a combination of tone values of a plurality of dots for each print head. Generally, the printhead is smaller than one pixel of image data. For example, in the case of the ink jet system, the resolution of pixel data is 360 dpi, and the print head is 720 dpi. The dot gradation value is a binary value of on or off, or a multi-value including some intermediate stages. Therefore, in such a case,
Combine several print heads into one unit,
The image data is printed by appropriately allocating (modulating) the gradation value of one pixel of the image data according to a predetermined rule.

Next, a multicolor reproducing apparatus 2 according to another embodiment is described.
Will be described. FIG. 7 is an overall configuration diagram thereof. This apparatus inputs raster image data including a spot color and outputs a printing plate for printing with process ink and one or more auxiliary color inks. Reference numeral 60 denotes a color correcting device for multicolor reproduction.
The difference from the multi-color reproduction color correction device 10 of FIG. 1 is that the first process color conversion unit 13, the second process color conversion unit 14,
And that the process color conversion LUT group 17 is omitted. Also, a printing plate output device 70 is connected to the color correction device 60 instead of the print engine 30.

The chromaticity value of the used special color is set in the special color chromaticity value memory 12 before the input image data is read into the multicolor reproduction color correction device 60. LU for multicolor separation
T is prepared as a combination of a process color and an auxiliary color used for printing. The operation of the multi-color reproduction color correction device 60 is the same as the multi-color reproduction color correction except that process color conversion is unnecessary because the process color of plate making data as input and the process color of plate data as output match. The same as the device 10. That is, S60, S62, S6 in the flowchart of FIG.
8. Each step of S70 operates according to the flow from which the steps are deleted.

The obtained image data for each printing ink color is sent to the plate output device 70. The printing plate output device 70 modulates the image data of each color into a signal for appropriately operating a driving system (laser beam or engraving head for mechanically engraving) for printing plate output, and outputs a desired printing plate. obtain.
In the case of printing a packaging material, a light color (for example, Y for M) is dark (for example, Y in the vicinity of a boundary where two or more colors come in contact with each other when image data of a color plate used for printing is obtained). :
A process (so-called niggling process) for expanding the area of M) with respect to Y by about 0.2 mm is performed. This is the printing plate output device 70
Or the multi-color reproduction color correction device 60.

According to the multi-color reproducing apparatus 2, since it is sufficient to prepare some auxiliary color inks in advance, it is not necessary to prepare various special color inks for each print item. Since the order quantity per ink color also increases, it leads to a reduction in ink cost. In addition, since the number of printing plates is constant, management in the printing process is also facilitated. There are many advantages.

As described above, two embodiments according to the present invention have been described. However, various other embodiments can be implemented without departing from the gist of the present invention. For example, the first process color conversion means may have a configuration not according to Document 1.
Further, a method of configuring a three-dimensional LUT has been described in order to specifically show the embodiment, but this is not limited to the described method. Before performing the first process color conversion (S60), for example, when C> 97, the second process color conversion unit determines that a specific combination of CMY values such as cannot be reproduced with the process colors of the multi-color proofing device May be configured to perform a condition determination on. Also, in the second process color conversion, a method of estimating a chromaticity value from CMY values, a configuration of the multicolor separation means 15, a procedure of first selecting an optimum LUT, and a calculation method of obtaining an optimum three-color separation value from the optimum LUT Is not limited to those described here.

[0045]

As described above, according to the present invention,
By using a multicolor DDCP that uses five or more color materials, a digital proofreading faithful to color reproduction by DDCP of printing plate making data including a special color can be obtained rationally. Conventionally, DDC is used for printing plate making data including spot colors.
Although P could not be used effectively, according to the present invention,
In particular, in the field of packaging printing, effective use of DDCP can be expected to be promoted. Especially in the case of gravure printing, DD
By making effective use of the CP output, the number of times and time required for the machine to be present at the printing site can be reduced, and reduction in printing cost and delivery time can be expected.

Further, according to the second aspect of the present invention, there is provided a multi-color reproducing color correcting apparatus in which a process color used in a multi-color reproducing apparatus or a printing apparatus matches a process color of original input image data. It can be realized with the minimum necessary configuration. When a multi-color reproducing apparatus is configured by using this color correcting apparatus, the special color ink to be prepared for each printing can be replaced with a fixed number of auxiliary color inks, leading to a reduction in printing cost.

[Brief description of the drawings]

FIG. 1 is an overall view of a multicolor proofing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for preparing a multi-color reproduction color correction device 10;

FIG. 3 is a flowchart showing the flow of the overall processing operation of the multi-color reproduction color correcting apparatus 10.

FIG. 4 is a flowchart illustrating a flow of a processing operation of the multicolor separation unit 15;

FIG. 5 is a diagram illustrating an example of a method of configuring a three-dimensional LUT, which is one of the process color conversion LUTs referred to by the first process color conversion unit 13.

FIG. 6 is a diagram illustrating an example of a method of calculating a three-color separation value from a designated chromaticity value S of the multi-color separation unit 15.

FIG. 7 is an overall view of a multi-color reproduction device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multicolor proofing device 2 Multicolor reproduction device 10 Multicolor reproduction color correction device 12 Special color chromaticity value separation value memory 13 First process color conversion unit 14 Second process color conversion unit 15 Multicolor separation unit 16 Control unit 17 LUTs for process color separation 18 LUTs for multicolor separation 30 Print engine 40 External storage device 50 Input device 60 Color correction device for multicolor reproduction 70 Printing plate output device

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Riki Nakagawa 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo Dai-Nippon Printing Co., Ltd. F-term (reference) 2C262 AA24 AA29 AB11 BA01 BA14 EA10 FA13 5C077 LL12 LL19 MM27 PP31 PP33 PP37 PP38 PQ08 PQ22 PQ23 RR19 TT08 5C079 HA19 HB03 HB11 LA02 LA28 LA31 LB01 MA02 MA05 MA10 NA03 PA07

Claims (4)

[Claims] 1. Raster image data including special colors other than the four process colors is input, and C (cyan), M (magenta),
In a multicolor reproduction color correction apparatus for a multicolor proofreading apparatus that reproduces four process colors of Y (yellow) and K (black) and one or more auxiliary colors as component colors, the input image data is If the color is reproduced in the process color,
A process color conversion means for performing color correction so as to be able to reproduce with the four colors of the process of the multicolor proofing device; Multicolor separation means for performing multicolor separation into component colors including auxiliary colors of the color proofing device, and when the input image data includes a special color component, a preset chromaticity value of the special color is used. After reading, the multi-color separation unit is activated to perform multi-color separation, and if not, the process color conversion unit is activated and converted to process color, thereby obtaining multi-color data from the input raster image data. Multi-color reproduction color correction device that creates separation data for each component color of the color proofing device 2. Before or after the process of the process color conversion means, it is determined whether or not the image data can be reproduced with the process color of the multicolor proofing device, and it is determined that the image data cannot be reproduced with the process color. 2. The multi-color reproduction color correction device according to claim 1, further comprising a second process color conversion unit that estimates a chromaticity value of the color and activates the multi-color separation unit. 3. A multi-color reproduction engine according to claim 1 or 2, further comprising a multi-color print engine for receiving separation data of each color, performing a screening process, and driving and outputting a print head. And a multicolor proofing apparatus characterized by comprising: 4. Raster image data including special colors other than the four process colors is input, and C (cyan), M (magenta), and Y
(Yellow), K (Sumi) 4 process colors and 1 other color
In a multi-color reproduction device or a multi-color reproduction color correction device for a printing device that reproduces colors as component colors of auxiliary colors or more, color samples are measured in advance, and the designated chromaticity value is received and used. When the input raster image data includes the component of the spot color, a chromaticity value of the spot color set in advance is read out, and Activate color separation means to perform multi-color separation with the process color and the auxiliary color, otherwise, use the raster image data of the four process colors as they are, and use them in the multi-color reproduction device or printing device A multi-color reproduction color correction device that creates separation data for each component color.