HK1098278B - Method for matching printing ink colors - Google Patents

Description

Method for matching printing ink colors

The application is a divisional application of Chinese patent application 2004100431600 with the application date of 2000, 10, month and 9.

Technical Field

The present invention relates generally to methods of manufacturing printing inks, and more particularly to an interactive system that communicates with a remote location for color approval and provides printing inks to the remote location for printing consistent colors.

Background

Many companies invest to have a national or international impact and suppliers that try to enhance the advantages of their customers can provide the same quality of product or service to countries or anywhere in the world in their network. Domestic or international companies have also tried to establish an image providing more services and having excellent research results based on the combination and supplement of efforts among a plurality of teams which are geographically independent but work in cooperation to meet customer needs.

The same appearance of labels and product text is a tool that effectively represents an internationalized and unified market situation. Although companies with domestic or international business desire the same appearance, printing is usually done on a local scale by individual small, independent printers. Color differences between different places and even between different printing batches of labels, product booklets or other printed matter can occur due to introduced errors due to subjective color matching methods, slightly different color standards, different equipment and different printing conditions. The color of the printed material can also be varied by printing using different methods, for example using a lithographic method or using a gravure method. Different types of inks may be used depending on the particular printer, such as heat set inks or drying inks. These differences in printed material detract from the image that a domestic or globalization company would like to stand with great and consistent effort.

For these reasons, there is a need for a method that ensures an optimal match in terms of color and quality regardless of the geographical location at which the material is printed.

Disclosure of Invention

The present invention provides a system that allows print purchasers ("print buyers") to obtain printed material having matching print colors even if the ink is manufactured in different locations, the material is printed by different printing companies at remote locations, and the printing is performed in different ways.

The present invention also provides a computerized system with remote access capability that determines the color and formula of a desired ink that results in a matched ink color from a given universal ink base color family. A method of determining a desired ink color includes using spectral or other data defining the desired color, using an interface for comparing standard colors with a customer approved selected ink color, using an optional program that adjusts the ink color (and the recipe corresponding to the ink color) based on customer input, and optionally using a link to a dispensing system that contains the base colors of the inks in the recipe and mixes these base colors to make the ink.

In a preferred embodiment, the synthetic ink formulation is in accordance with the print purchaser's code or product code, so that additional batches of ink can be prepared using the same or other printers used to print material for the print purchaser.

In another aspect, the invention provides a method of determining a desired print color in a computer operating system having remote access capability, in which the desired print color is input into a color matching program, which is first converted, if necessary, to coordinates to be used by the color matching program. The color matching program uses the desired color data and other optional data associated with the desired ink type information to formulate a color matching ink formulation. The formulation is then electronically transferred to a production facility that produces the ink according to the synthetic ink formulation. The computer operating system preferably confirms that the input color and the composite ink formulation are consistent with what the print buyer expects in order to prepare additional batches of ink of exactly the same color.

Drawings

FIG. 1 is a block diagram of a preferred embodiment of the system of the present invention;

FIG. 2 is an information screen displaying the results of electronic color matching in one embodiment of the present invention;

FIG. 3 is a screen of a graphical user interface in one embodiment of the present invention;

Detailed Description

Using a computerized system with remote access, each color selection, selection of ink formulations to match the selected color, color matching approval, and ink manufacturing equipment can be remotely located but still controlled to produce prints of the same quality and color. Where "remote" means located at a different location. The color approval process is implemented by computer communication. The advantage of the invention is that, as will be apparent from the following description, the location of the desired color to be input, the location of the ink formulation to be matched to that color, and the location of the ink to be produced according to that formulation can be located in different parts of the world, the system of the invention also enables the whole process from the initial input of the desired color to the production of the ink to be completed within a day or even hours.

In one aspect, the method and system of the present invention are illustrated with reference to FIG. 1. In the embodiment shown in fig. 1, the remote location includes a spectrophotometer 2, a first computer (central processing unit) 4, a color monitor 6 electronically connected to the computer, and a viewing chamber 8. Spectral data of a color sample of a desired color is obtained using a spectrophotometer. The desired color data is input to the computer 4 and transmitted to the second computer 10.

In the illustrated embodiment, the second computer is designated as a server or host, but requires that the first computer and the second computer be able to communicate with each other. The present invention is not limited to a client-server relationship and it is readily appreciated that other relationships are possible that allow a first computer to communicate with a second computer. The invention thus relies on a communication system, such as a global communication network. The internet (which is based on transmission control protocol/internet protocol, or TCP/IP) is one such global communications network. Each printer client can see the effect of color matching by applying the communication mode. In a preferred embodiment, the system uses an Internet (i.e., TCP/IP) graphical user interface to interact with individual printer customers, print buyers, package designers, and others who wish to achieve ink color matching. The system preferably includes an Internet second computer or server that functions as a second computer, which interacts with the client through the client's first computer or client interface. The customer (whether the printer, designer, or print purchaser) can enter the ink color and type, and/or verify the color identified by the system and displayed on the customer's monitor 6. These functions may be provided by a server-side program that receives information entered by the client (through a common gateway interface) or by a client-side applet (e.g., Java) downloaded to the client and executed in the client computing environment.

In one aspect of the invention, the server is capable of handling multiple requests occurring simultaneously. The server may communicate the customer information and the selected ink formulation information to the production facility, which is selected by the server according to established guidelines. The guidelines include, for example and without limitation, the conditions that are close to the customer's printing, whether the production facility has the necessary materials for the ink formulation in the list, or will have those materials in time to meet the customer's needs, and the capabilities of the production facility.

A second computer 10 (illustrated as a server) selects an ink formulation and transmits color data associated with the selected formulation to the first computer 4, the colors of the selected ink formulation being displayed on the color monitor 6 and approved by the customer at a remote location. The color of the selected ink formulation can be observed under different lighting conditions in the observation chamber 8, for example daylight D65, cool white (cool white) fluorescence and incandescent lighting.

The server 10 uses three software packages 12, 20, 22 to select an ink formulation that matches the desired color. Software package a12 passes information back and forth between the other devices of the system. The spectrophotometer 14, color monitor 16 and viewing chamber 18 are used in both cases. In the first case, they are used to create a color database that relates the series of primary colors of ink used to make the ink, or by adjusting or updating the database to reflect changes in the series of primary colors of ink or additions of colors to the series of primary colors. In the second case, they are used to monitor the results of the ink color selection so that the producer sees the same results as a person at a remote location.

The software package B20 converts color spectrum data entered by the computer 4 or in the database software 22 into digital information that will produce the same color on the monitors 6 and 16.

Software package C22 includes a color information database for producing color information for a base color family of inks. The software package C22 uses this database information to select an ink formulation that produces a printing ink that best matches the desired color within specified other parameters. Other parameters considered by the software package C22 include selecting a most economical formulation that is not greater than a specified color difference-E from the desired color, selecting a formulation with a given chemical resistance, selecting a formulation for a lightfast ink undertone, and the like. Basically, color matching involves replicating the chromatographic curve in the visible spectrum of 400-700nm, the replication should be as close as possible to the limits of a given formulation. Color matching is described in more detail below.

When the customer at the remote location agrees with the selected color, the customer sends a license from computer 4 to server 10 to produce ink. The server 10 then transmits the recipe data to the automatic dispensing device 24. The automatic dispensing device 24 dispenses and mixes the individual ink base colors specified in the ink formulation to produce ink. The ink is then packaged and shipped to the printer.

In the first step of the method, the printer-customer enters the desired information relating to the desired printing ink and other information relating to the ordering of the printing ink. The information is preferably entered by the customer through a graphical user interface and transferred from the first computer (client) to the second computer (server), although the information could be sent by the customer to the second computer or server in other ways, such as by telephone or telephone fax. Fig. 2 shows an example of an interface for inputting information. The information entered by the customer includes the desired designated color and the identity of the printer and preferably the identity of the purchaser of the printed product for which the printing is to be made. Additional information about the ink order may also be entered, such as ink requirements, shipping methods, customer location, and authorization for customer payment.

It is particularly preferred to include additional information about the printed substrate, the printing equipment and other information affecting the color matching in terms of substrate and ink properties. Examples of such information include, and are not limited to, substrate type, substrate color, printing method (e.g., offset, gravure, sheet, flexographic, etc.), type of printing equipment, printing speed, and/or ink type or desired ink properties (e.g., uv cured, chemical resistant, solvent based or water based, air dried, heat set, etc.).

It is also possible to input information from two or more separate locations. For example, color spectrum data is obtained and entered at one location, and other information is entered from a second location, so long as it is recognized that the information from both locations belongs to a single order file.

Various methods of inputting a desired color can be envisaged. In one embodiment, the desired color is input in the form of appropriate color space coordinates. Color coordinates can be obtained using, for example, a reflectance spectrophotometer, and using, for example, color coordinates X, Y, Z, or L^＊，a^＊，b^＊Or cylindrical coordinates r, theta, L or L^＊，C^＊，H^＊Is shown. The color coordinates can be entered directly from the spectrophotometer, by a keyboard, mouse or trackball, or otherwise. Although color can be measured by other instruments, such as colorimeters, these methods have more limitations and more accurate color matching can be obtained with spectrophotometers.

In a second embodiment, the color can be selected from a library of colors displayed on the client computer monitor. The customer can select the possible colors using the electronic input device. Any electronic input device can be combined with appropriate software including, but not limited to, a keyboard, mouse, trackball, light pen, electronic tablet, touch screen, voice recognition device, and the like. The colors are displayed in a manner such as an array of color patches or boxes, in a color sequential manner such as a color space, or in other suitable manners. For example, the color may be selected from a plurality of colors that the monitor can display, and for color matching, the numerical designation of the selected color is communicated to the component of the present invention that determines the ink formulation of the closest color. In a preferred embodiment, the selected color occupies a greater portion of the new screen viewing area, allowing the customer to compare the selected color to the standard color and verify the color selection.

In the third embodiment, a desired color is input by scanning with a color standard using a scanner having an accurate color reproduction capability, photographing the color by a digital camera, or the like. The inputted color may be displayed on the terminal screen.

In another embodiment, the desired color is specified by reference to a color in a color guide or a sample book of a different color, such as the color guide published by Pantone, incColor Formula Guide ". A database containing color data defining each color can be accessed, and then the color data specifying the color is used as beforeThe formula that achieves the closest color match from a given ink base color family is determined.

In various methods, the customer can enter a code assignment for the color that has been matched. Thus, once a print purchaser selects a color, the color is matched and assigned a unique code for the first use in the method, and the same color can be selected later (by the first printer or any subsequent printer) by entering the unique code without further color matching steps.

In making the color matching, the server accesses a color matching program to produce an ink formula of the specified color. The color matching program compares color information input by a customer with color information in a database and selects an appropriate proportion of the primary colors of the ink to complete the closest color matching, wherein the database contains primary color data of the primary colors of the ink used for preparing the ink. The database consists of measuring the color information of printed samples prepared from a series of base colors of the ink and/or from mixtures thereof having different concentrations or intensities. The database includes a sufficient number of color information points to enable the computer to infer color information resulting from different combinations of the series of primary colors of ink, if desired. In other words, the computer is able to calculate a composite spectral curve or other color information for an ink formulation based on the color information obtained for each of the primary ink colors containing different concentrations.

The color information used to construct the color matching database is typically obtained by a proofing program for the ink, for example using an IGT proofer, preferably measuring the color information with a reflectance spectrophotometer.

Color matching can generally be achieved in a number of ways, some of which can provide more accurate results. First, the second computer compares the spectral profile in the visible region of the desired color with the possible spectral profiles of the individual ink formulations and selects the ink formulation or formulations whose spectral profile is closest to the desired color profile. The comparison can be performed using standard curve fitting techniques such as least squares fitting. In the second colorIn the art, the desired color can be expressed in terms of color space coordinates, such as CIE coordinates L^＊a^＊b^＊，L^＊C^＊H^＊Or L is^＊u^＊v^＊. When color matching uses color coordinates, existing color tolerance methods can be used to calculate the color difference between two points. CIELAB is a common method of calculating the color difference-E, as follows:

-E＝Sqrt[(a1^＊-a2^＊)²+(b1^＊-b2^＊)²+(L1^＊-L2^＊)²]

in the CMC color tolerance method, the color difference-E surrounds the standard color and corresponds to the hue (hue) (S)_H) Chroma (S)_C) Brightness (S)_L) The ellipse of the half-axis:

-E＝Sqrt[(-L^＊/lS_L)²+(-Cab^＊/cS_C)²+(-Hab^＊/S_H)²]

where the luminance coefficient l is 2 and the chrominance coefficient c is 1.

The program for comparing the expected colors to determine the most suitable matching color is for example the color matching software marketed by COLORITE, Datacolor corporation of lawrenceville, NJ (geographical name). CIELAB color coordinates can be calculated from the total reflectance spectrum using the formula published by CIE (Commission International de I' Eclairage). There are also tools such as an X-Rite 938 (model) spectrodensitometer available from X-Rite corporation of Grandville, MI (place name) which can provide CIELAB coordinates directly.

Since the printed color appears differently when viewed under different light sources, color information of the printed color appearing under different light sources, such as sunlight, D65 daylight, cold white fluorescence, and incandescent light, is preferably included in the database. The color information for the desired ink color for each different light source is then input and color matching is performed by determining the minimum color difference-E while taking into account the ink colors for all different light sources.

Color matching may also be determined by comparing reflectance values in the visible spectrum of both the expected color and the color identified by the color matching program. A least squares calculation may be performed to determine the ink formulation whose spectral curve most closely approximates the spectral curve of the expected color standard, wherein the spectral curve of the ink formulation may be inferred from information on the measured spectral curves in the database.

The color of the selected formula is displayed on the customer monitor for approval by the customer. In this context, a "customer" may be a printer and/or a purchaser of printed matter and/or a designer of packaging or other printed media. For example, the color of the selected formula is displayed on a half area adjacent to the half area displaying the color input by the customer, or the color of the selected formula is displayed in a color window shown on the monitor screen together with other data. An example of such a screen is shown in fig. 3. Upon approval of the color, the customer compares the intended color with the selected color for each of the different light sources. Alternatively, the second computer transmits a display showing how the intended color and the selected ink color are compared under different lighting conditions.

In order for the display to successfully display the results of the color matching calculations for the ink base color series, the display must be able to faithfully reproduce the primary colors. It is known how to calibrate the color of a monitor so that the monitor accurately displays a selected color. Calibration can be performed using commercial calibration systems, such as those available from X-Rite, Inc. of Grandville, MI (place name) and Datacolor, Inc. of Lawrence ville, NJ (place name). Typically, such calibration involves the use of standard tiles (tiles) of known reflectance values.

In the same way, the results of the color matching method can be sent to the customer in different forms to obtain color approval. First, the color of the selected ink formulation and the desired color may be displayed side-by-side on a monitor. The monitor 6 must be properly calibrated to accurately display the color of the selected ink formulation and the desired color to be matched. With the observation room 8 having variable illumination conditions, the display of colors on the color monitor 6 can be observed at different illuminations. Alternatively, the second computer 10 can electronically calculate how each color is displayed under the selected different lighting conditions and send the results to the first computer, including the color that is expected to be displayed under each selected lighting condition, as well as the color of the selected ink formulation.

The user may agree to the displayed color or request a color modification. For example, the user may send a request back to the color matching program asking the color to light up and then observe the results of the request. Rather than manually preparing a new ink color, printing the color proof, and sending the proof to the customer, taking several days, the results will be returned to the customer for viewing and approval in a matter of minutes.

Optional criteria for selecting ink formulations may be established to meet the needs of the printer or print purchaser. For example, the system may no longer select the closest color match possible, but instead decide the formula with the appropriate color match and at the same time the lowest cost, specified by the determined Δ E. The base color containing the specific attribute can also be used to determine the closest color match. For example, a set or subset of ground colors can be used to prepare inks having particular properties, which can be selected from: chemical resistance, light resistance, radiation curable, heat resistance, foilastampability, uv coatability, laser imprintable, and combinations thereof. The information entered along with the desired color may include whether such a particular attribute is desired in the ink. When specified to have certain specific properties, such as chemical resistance, the system of the present invention uses only those ink undertones specified for that property in determining the ink formulation.

The ink formulas corresponding to the input colors may be stored in a database that is linked to the print buyer information provided by the customer, the customer identification and order information, data approved by the printer, the print buyer, or designer, or other information.

A formula is determined for a first type of ink, such as offset ink, and when a second type of ink, such as gravure ink, is desired to have the same color, the color data of the first type of ink becomes the desired color data, and the formula for the second type of ink is determined in the same manner using the base color of the ink.

Additional information may be entered into the program that determines the matching formula so that color matching and ink performance are guaranteed for a particular print job. For example, it is known that the ink colors vary depending on the substrate being printed. For example, the inks may appear differently in the case of a colored substrate as compared to a white substrate, or in the case of printing on different grades of paper, in the case of a coated material as compared to an uncoated material, in the desired thickness of the printed layer, or in the case of printing on a plastic or metallic material as compared to printing on paper. The calculation formula preferably takes into account the possible color changes that may be introduced by the printed substrate if such color changes occur. The types of parameters that may be considered in calculating the recipe include, for example and without limitation, the type of substrate, the color of the substrate (which may also be input as spectral data or selected in any manner already discussed in connection with inputting the desired ink color), the absorbency of the material, its weight when the material is paper, whether the paper or cardboard material is coated or not, and the like.

The determined ink formulation is then transferred to the production facility. The production facility may include, for example, an automatic dispensing system that accurately dispenses the amount of each base color in the formulation to produce the ink. And the automatic dispensing system may be electronically connected to a program that receives customer data and determines the correct ink formulation. The dispensing system may also be controlled by manually entering information, such as via a keyboard. The produced ink is then shipped to the customer.

The system may also include production related components such as labeling software, inventory software, and accounting software. These components are well known in the art and need not be described further.

With the system of the present invention, the overall process of the current method greatly reduces the time required to match the customer's color, produce the correct color of ink, and deliver the ink to the customer. In this method, a customer sends a color sample to an ink manufacturer, who develops an ink formulation that matches the color of the sample, and finally produces the formulation and sends the ink to the customer.

In a preferred embodiment, the system provides ink to offset printing equipment, including sheet printing equipment and web printing equipment, although the invention is applicable to other types of printing inks, such as gravure printing, flexography, and screen printing. The inks may be radiation curable (including ultraviolet curing and electron beam curing), air curable, cold curable (absorbing inks such as newink), thermosetting, water based, or solvent based.

For example and without limitation, the set of base colors used to produce lithographic printing inks may comprise a set of different ink colors that contain the same varnish or carrier system and that are capable of producing a wide range of colors upon mixing. The primary color series typically includes at least 12 primary colors and may include 40 or more primary colors. While increasing the number of primaries increases the complexity of the dispensing and mixing system, it also increases the ability of the system to closely match customer colors and meet customer requirements for specified ink properties such as solarization resistance, high temperature resistance, and chemical resistance.

In a preferred embodiment, in order to obtain excellent printing characteristics in a variety of printers, it is preferable to select a varnish based on the base color series.

In another embodiment of the invention, the viscosity or other properties of the already color-matched ink can be adjusted to suit the particular printer, for example by adjusting additives in the ink or by adjusting different proportions of varnish in the ink. These adjustments are made depending on the printing design and configuration, the type of ink-holding solution (fountain solution) or the type of printing plate of the lithographic process, etc.

Various printed materials including brochures for introduction and sale, inserts, magazines, catalogs, corporate financial statements and annual reports, packaging materials including cardboard, other containers, and labels, etc. may be made using the method of the present invention.

The invention has been described in detail with reference to preferred embodiments thereof. It will be understood that various changes and modifications may be made within the spirit and scope of the invention and the following claims.

Claims (5)

1. A method of dispensing ink comprising the steps of:

inputting data of a desired printing color and at least one parameter selected from the group consisting of: ink properties, ink type, cost, printer identification, printing method parameters, printing equipment, printing method, printing equipment type, printing speed, substrate type, substrate color, and various combinations of the foregoing parameters;

using the selected ink base color based on the at least one parameter, obtaining, with a first computer, predicted print color information for the ink formulation,

for the at least one parameter, an ink formulation having a desired match to a desired color is selected using a color matching software program.

2. A method of providing two ink formulations comprising the steps of:

selecting a first ink formulation according to the method of claim 1, and

selecting a second ink formulation according to the method of claim 1,

wherein the first ink formulation is the same as the expected print color of the second ink formulation, and further wherein at least one of the ink type and the substrate type in the first ink formulation is different from the second ink formulation.

3. The method according to claim 2, wherein the predicted printed color of the first ink formulation has only one specified color difference compared to the predicted printed color of the second ink formulation.

4. The method of claim 2, wherein the first computer transmits display data to the second computer to display the print color of the first ink formulation and the print color of the second ink formulation on the monitor.

5. The method of claim 4, wherein the first computer further transmits display data to the second computer to display the desired color on the monitor.