Inkjet printing proofing method

Abstract

To make it possible for quick jet printing that supports a small lot order and is excellent in on-demand performance to avoid interference of human labor as much as possible.SOLUTION: In color matching that matches a color presented by a client's color sample and a color of a printing result with respect to calibration of jet printing, not only is the color presented by the client according to the color sample measured by a color meter, but also each color outputted to a color chart printed with a printer performing printing is measured by the color meter; a color similar to the color presented by comparing numerical value is searched for, and the client is made to choose, whereas the color chart and the printed matter are presented by photographing them with the color meter and transmitting / receiving images on a network.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a calibration method in inkjet printing.

Background Art

[0002] In printing based on a manuscript presented by a customer, a process called prepress, which performs preprocessing necessary for starting printing in a printing apparatus, is required. In prepress, the printing design manuscript provided by the customer is subjected to image processing on the order-receiving side to create a printing manuscript for a printing machine. In this process, it is essential to perform a proof print and perform calibration of the printing result with the customer involved. In particular, color matching in the solid areas of printed matter was important. This work is performed by comparing the color samples passed from the customer as part of the printing design manuscript with the colors in the proof print.

[0003] In gravure printing, for the solid areas of printed matter, a special ink (a mixture of a plurality of color inks to approximate the color sample - Patent Document 1 -) is used, and the operator visually determines the color including delicate color adjustment for color matching. The printed matter is finally numerically managed by the color difference △E of a color difference meter.

[0004] FIG. 2 shows the color separation procedure in the above case, Procedure for receiving a color sample from the customer, Procedure in which the operator visually observes the color sample and creates a special ink by mixing a plurality of color inks, Procedure in which the operator determines the color of the special ink, Procedure for setting the special ink in the printing machine that executes printing and performing color separation, Procedure in which the operator determines the printed color, Ending the color separation, ~ consists of the procedures.

[0005] FIG. 3 shows the color calibration procedure after color separation in the above case, Procedure for performing color separation multiple times, Procedure in which the customer performs color calibration and determines the color, The procedure involves remaking the ink that passed the color proofing, setting it in the printing press, and then performing the final color matching. The customer performs color proofing again and determines the color. After completing color proofing, the finished products are measured using a colorimeter and managed under △E control. ~It consisted of steps.

[0006] On the other hand, while color proofing is possible for the color tones of the color samples (designs in image data) provided by the customer, both gravure printing and inkjet printing can perform color proofing using optimal color-managed profiles. However, for solid areas, inkjet printing, which reproduces colors using halftones of process colors KCMY, could not use special inks like those used for color matching due to the machine's structure.

[0007] As a result, in inkjet printing, several color schemes close to the sample were selected from a color chart created from pre-prepared process color KCMY color schemes and submitted to the customer as color proof samples.

[0008] Figure 4 shows the procedure for producing the color in the above case. Procedure for receiving color samples from the customer regarding solid areas, A procedure in which an operator visually inspects a color chart printed on a printing press and selects multiple colors that match the color sample. Procedure for setting image data with multiple color schemes. Procedure for producing multiple colors, Procedure for workers to determine the ink color, Procedure for setting the image data to a re-selected color scheme. Procedure for producing the colors of the re-selected multiple colors, The worker determines the ink color. ~It consisted of steps.

[0009] Figure 5 shows the procedure for color proofing after color rendering in the above case. Procedure for performing multiple color extractions, The procedure for printing a specified design (multiple colors on one side) on a printing press. A procedure for customers to perform color proofing and determine the color of solid areas. The procedure for setting the color scheme that passed color proofing to the entire image data. The procedure for developing the final color, The customer performs color proofing again and determines the color. After completing color proofing, the finished products are measured using a colorimeter and managed under △E control. ~It consisted of steps. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 11-296664 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0011] In the aforementioned case, the contractor's workers would visually inspect a color chart printed on the contractor's printing press and select colors that matched the customer's color sample. However, this process was extremely complicated and time-consuming. Furthermore, differences in color perception among workers, as well as factors such as their physical condition, could lead to variations in color selection. As a result, it was impossible to present a printed design that nearly perfectly matched the color sample, leading to the presentation of printed designs displaying multiple approximate colors, which was extremely inefficient.

[0012] Incidentally, in the printing industry, it is customary for customers to visit the printing factory and make a final decision on the printed materials when placing an order. When printing with inkjet printers, it is necessary to print multiple color schemes in advance and have the customer present for final approval. However, due to the recent COVID-19 pandemic, customers are unable to visit printing factories in person, so it has become necessary to send printed materials to customers by mail for their approval. In particular, with inkjet printing, which has the aforementioned problems with solid color areas, the number of color proofs required increases, and the number of mailings also increases, resulting in a considerable delay and making it difficult to meet customers' demands for short delivery times.

[0013] Inkjet printing is optimal for quickly performing small-lot on-demand printing, but due to the above problems, it is impaired, and there is a problem that the advantage is not utilized.

[0014] Inkjet printing is optimal for quickly performing small-lot on-demand printing, but due to the above problems, it is impaired, and there is a problem that the advantage is not utilized. In particular, in the case of gravure printing, since the same pattern is printed on multiple surfaces, the prepress work is one pattern per order, while in the case of digital printing, there are many cases where several different patterns are printed on multiple surfaces. Therefore, it must be noted that if digital printing prepress work is ordered based on the feeling of conventional gravure printing, there is a high possibility that the profit and loss cannot be achieved.

[0015] In the above case, since the customer is creating a color proof with a digital printer, it seems that the problem of color matching can be solved if the orderer uses the print data. However, since the printer used by the customer and the printer used by the orderer are different, even if they are based on the same data, the colors of the printed results output do not exactly match.

Means for Solving the Problem

[0016] The present invention was created for the purpose of providing a calibration method for inkjet printing that solves the above problems.

[0017] That is, the calibration method for inkjet printing of the present invention is A procedure for receiving a print original from a customer, A procedure for receiving color designation from a customer by a color proof for solid parts, A procedure for measuring the color presented by the color proof with a colorimeter, A procedure for printing a color chart with the orderer's printer, A procedure for measuring each color developed on the color chart with a colorimeter and saving the measurement data in a color chart measurement data file, A procedure for searching for similar colors from a color chart color measurement data file using color measurement data of colors presented by the customer. The procedure for printing multiple similar colors found through a search onto a single surface. The procedure for obtaining an image by photographing the above printed material with a colorimeter, The procedure involves sending the above image to the customer via the network and having the customer select a color. The procedure for obtaining a proof print by printing the entire document using the customer's selected color for the solid areas, and then printing the entire document. The procedure for obtaining an image by photographing the above proof printout with a colorimeter, The procedure involves sending the above image to the customer via the network and having the customer proofread it. It is characterized by having the following features.

[0018] Furthermore, the invention described in claim 2 is a calibration method comprising the steps of measuring the color of a color chart created by a printing press used by a customer to print color samples using a colorimeter and converting it into color measurement data. The procedure involves comparing the above color measurement data with the color measurement data of the colors presented by the customer's color swatch, and determining which colors from the customer's color chart were used to determine the color scheme. It is characterized by having the following features.

[0019] Furthermore, the invention described in claim 3 is characterized in that, in the calibration method described above, the customer saves the color measurement data of the color chart created by the printing press that prints the color sample as profiles for the customer and for each printing press used by the customer.

[0020] Furthermore, the invention described in claim 4 is characterized in that, in the calibration method described above, the colorimeter is a camera-type two-dimensional colorimeter having optical filters with three spectral sensitivities (S1(λ), ​​S2(λ), S3(λ)) that are linearly transformed to be equivalent to color functions such as the XYZ color matching functions of the CIE.

[0021] Furthermore, the inventions described in claims 5 and 6 are characterized in that, in the calibration method described above, the color measurement data of the color presented by the color sample and the color measurement data of the color selected by the customer from a plurality of similar colors that have been produced are recorded in a customer database in association with the customer, the customer's preference trends regarding color differences are analyzed, and when presenting the plurality of similar colors that have been produced to the customer, the customer's preference trends regarding color differences recorded in the database are referred to and the color that matches the customer's preference trends are given priority in presenting the color. [Effects of the Invention]

[0022] The primary feature of the inkjet printing proofing method of the present invention is that, instead of the contractor reusing the print data from the customer's digital printing press to generate the colors to be printed, the contractor identifies a hard copy output by the customer on the customer's printing press as the color sample provided by the customer, measures its color using a colorimeter, and converts it into color measurement data.

[0023] Next, a second characteristic is that the contractor identified a hard copy output from a printing press used for printing as a color chart, and then measured its color using a colorimeter to create color measurement data.

[0024] Furthermore, the contractor uses the color measurement data of the color presented by the customer's color sample to search for a similar color in the contractor's color chart color measurement data file and prints the color on the contractor's printing press. This eliminates the problem of color differences between the contractor and the customer due to differences in their printing presses.

[0025] On the other hand, since the above procedure can be mechanized using IT without human intervention, not only is the work speed dramatically improved by eliminating human intervention, but it also becomes possible to eliminate uncertain factors such as the individual worker's sense of color and perform accurate color matching.

[0026] Furthermore, as in the invention described in claim 2, the color chart created by the customer using a printing press for printing color samples is measured by the contractor using a colorimeter and converted into color measurement data. The contractor then compares this color measurement data with the color measurement data of the colors presented by the customer's color sample. When determining which colors on the customer's color chart were used to determine the color scheme, the contractor can also understand the surrounding colors, making it possible to perform more accurate color matching.

[0027] Furthermore, if the customer saves the color measurement data of the color chart created by the printing press used to print the color sample as a profile for each customer and printing press used by the customer, as described in claim 3, the above work can be performed more quickly.

[0028] Furthermore, as in the invention described in claim 4, when measuring color using a camera-type two-dimensional colorimeter with an optical filter having three spectral sensitivities (S1(λ), ​​S2(λ), S3(λ)) that are linearly transformed equivalently to color functions such as the CIE XYZ color matching functions, it is possible to quantify the sensitivity of the human eye and present colors that meet the customer's requirements.

[0029] On the other hand, since the customer who ultimately makes the color judgment is a human being, they have preferences and habits regarding color selection. This is a different issue from the difference between the printing press of the contractor and the customer. In this regard, as in the invention described in claims 5 and 6, the color measurement data of the color presented by the color sample and the color measurement data of the color selected by the customer from multiple similar colors produced are recorded in a customer database in association with the customer, and the customer's preference trends regarding color difference are analyzed. When presenting multiple similar colors produced to the customer, the customer's preference trends regarding color difference recorded in the database can be referenced to find a color that matches the customer's preference trends, and by prioritizing the presentation of that color, it becomes possible to quickly perform color matching with fewer rework.

[0030] As described above, by quantifying the process, the need for human intervention can be reduced. This means that tasks such as receiving print manuscripts and having customers select colors can be done via image exchange over the network instead of face-to-face interaction. As a result, customers can complete printing orders and proofs online without having to visit a printing company or use postal services. This allows for small-lot orders, maximizes the advantages of on-demand and rapid inkjet printing. [Brief explanation of the drawing]

[0031] [Figure 1] A flowchart illustrating the procedure for the inkjet printing proofing method of the present invention. [Figure 2] A flowchart illustrating the color reproduction process in gravure printing. [Figure 3] A flowchart illustrating the color proofing procedure in gravure printing. [Figure 4] A flowchart illustrating a conventional procedure for color reproduction in inkjet printing. [Figure 5] A flowchart illustrating a conventional procedure for color proofing in inkjet printing. [Best Mode for Carrying Out the Invention]

[0032] Hereinafter, specific embodiments of the present invention will be described using the invention described in claim 6 as an example, following the flowchart in Figure 1.

[0033] Procedure S1 In inkjet printing, where the print source is received from the customer, the customer specifies the color for the solid areas based on a printed color sample.

[0034] Step S2 The colors presented by the color samples are measured using a colorimeter. In this embodiment, a two-dimensional colorimeter manufactured by Papalabo Co., Ltd., known from Japanese Patent Application Publication No. 2018-004423 and other sources, is used as the colorimeter. This colorimeter is a camera-type device with optical filters having three spectral sensitivities (S1(λ), ​​S2(λ), S3(λ)) that are linearly transformed to be equivalent to color functions such as the CIE XYZ color matching functions, and can quantify the sensitivity of the human eye.

[0035] Step S3 Next, the contractor prints a standard color chart using a printing press. Here, we assume the printing press is a DDCP inkjet printer.

[0036] Steps S4-S5 Each color displayed on the standard color chart is measured using a colorimeter, quantified, and the measured color data is saved to a color chart color measurement data file.

[0037] Procedure S1-1 We receive a color chart created by the client. This color chart was printed using the same printing press that the client used to print the color samples.

[0038] Procedure S2-2 Each color displayed on the color chart created by the client is measured and quantified as colorimetric data. In this case, the data is scanned using the DDCP scanner used by the contractor and then quantified as colorimetric data.

[0039] Procedure S2-3 The aforementioned color measurement data is saved in a profile data file as a profile linked to the client and the printing press used by the client.

[0040] Steps S6~S7 For colors presented using digitized color samples, the color difference is specified from each color displayed on the digitized color chart in the color chart measurement data file to search for the closest color, and the color is then reproduced on the customer's printing press. At this time, the customer and the profile data files of the printing press used by the customer are referenced, and the above color measurement data is compared with the color measurement data of the colors presented by the customer's color sample. This helps to identify which colors in the customer's color chart were used to determine the color scheme of the customer's color sample, and this is used as a reference for color reproduction.

[0041] Step S8 The system determines whether the customer is new or not. If they are new, the process proceeds to step S10; if they have previously placed an order, the process proceeds to step S10 via step S9. In this case, even if it is the same company, the system determines whether the customer is new or not based on the person who placed the order.

[0042] Procedure S10 In step S7, print multiple similar colors onto one surface. Specifically, for multi-sided designs, print each surface with multiple color schemes.

[0043] Step S9 Referencing a customer database that records customer preferences regarding color differences, when presenting step S10, prioritize presenting colors that match the customer's preferences. Prioritization here includes not only ranking the colors to be presented, but also presenting only one color.

[0044] Procedure S11~S12 In step S10, the printed material is photographed with a colorimeter to obtain an image. The obtained image is sent to the customer via the network, and the customer selects the color. In this case, if the customer's terminal monitor is specified as one that applies a highly reproducible technology known from, for example, Japanese Patent Application Publication No. 2012-217052, accurate color judgment can be made, enabling rapid proofreading. On the other hand, even if the specified monitor is not used, customers in remote locations can check the color and make requests via a PC or smartphone, which also contributes to speeding up the process.

[0045] Procedure S13 The customer's chosen color is used for the solid areas, and the entire document is printed to obtain a proof copy.

[0046] Steps S14-S15 The printed material obtained in step S13 is photographed with a colorimeter to obtain an image. The obtained image is sent to the customer via the network for the customer to proofread the colors.

[0047] Steps S16-S17 The color measurement data of colors presented using color samples, and the color measurement data of colors selected by the customer from multiple approximate colors, are analyzed based on the customer's preference trends regarding color differences and recorded in a customer database in relation to the customer. [Explanation of Symbols]

[0048] Steps in the flowchart S1-S17

Claims

1. In proofreading inkjet prints, Procedure for receiving print manuscripts from customers, Procedure for receiving color specifications from the customer using color samples for solid areas. The procedure for measuring the color of a color sample using a colorimeter. Procedure for printing the color chart using the contractor's printer. The procedure involves measuring each color displayed on a color chart using a colorimeter and saving the measurement data to a color chart color measurement data file. A procedure for searching for similar colors from a color chart color measurement data file using color measurement data of colors presented by the customer. The procedure for printing multiple similar colors found through a search onto a single surface. A procedure to obtain an image by printing multiple similar colors found through a search onto a single surface, and then photographing the resulting printout for displaying similar colors with a colorimeter. The procedure involves sending the above image to the customer via the network and having the customer select a color. The procedure for obtaining a proof print by printing the entire document using the customer's selected color for the solid areas, and then printing the entire document. The procedure for obtaining an image by photographing the above proof printout with a colorimeter, The procedure involves sending the above image to the customer via the network and having the customer proofread it. A method for proofing inkjet printing, characterized by having [a certain feature].

2. The procedure for taking a color chart created by a customer using a printing press to print color samples, measuring the colors with a colorimeter, and converting that data into color measurement data. The procedure involves comparing the above color measurement data with the color measurement data of the colors presented by the customer's color swatch, and determining which colors from the customer's color chart were used to determine the color scheme. A proofing method for inkjet printing according to claim 1, comprising:

3. The inkjet printing proofing method according to claim 2, wherein the customer saves the color measurement data of a color chart created by a printing press that prints color samples as profiles for the customer and the printing press used by the customer.

4. The method for calibrating inkjet printing according to any one of claims 1 to 3, wherein the colorimeter is a camera-type two-dimensional colorimeter having optical filters with three spectral sensitivities (S1(λ), ​​S2(λ), S3(λ)) that are linearly transformed to be equivalent to color functions such as the CIE XYZ color matching functions.

5. A proofing method for inkjet printing according to any one of claims 1 to 3, wherein the color measurement data of a color presented by a color sample and the color measurement data of a color selected by the customer from multiple similar colors produced are recorded in a customer database in association with the customer, the customer's preference trends regarding color differences are analyzed, and when presenting multiple similar colors produced to the customer, the customer's preference trends regarding color differences recorded in the customer database are referenced to prioritize the presentation of a color that matches the customer's preference trends.

6. The inkjet printing proofing method according to claim 4, which records the color measurement data of the color presented by the color sample and the color measurement data of the color selected by the customer from multiple similar colors produced in association with the customer in a customer database, analyzes the customer's preference trends regarding color differences, and when presenting multiple similar colors produced to the customer, refers to the customer's preference trends regarding color differences recorded in the customer database and prioritizes presenting the color that matches the customer's preference trends.

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