JPS63104900A - Color matching method of coloring liquid - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a color matching method for colored liquids, and more specifically, for a sample color whose spectral reflectance of a liquid film is known, coloring liquids, such as paints, inks, etc., are matched by the CCM method. This relates to a method of wet color matching without creating a dry paint film.

Conventional technology Visual color matching or computer color matching (CCM) is used to color match paints, inks, etc. However, in conventional color matching methods, when it comes to precise color matching, dry coating plates for color testing are used. The test results are determined by visual comparison with a dry sample coated plate or color difference measurement using a colorimeter. Normally, dry coating plates for color testing are prepared two to four times before the color difference from the sample plate passes the test, which takes time and effort, and variations in the production of dry coating plates affect quality accuracy. , resulting in longer process times.

Such color toning work by CCM is well known, but in the conventional method, paint is applied to a substrate, dried under predetermined conditions, a coated plate is prepared, and the spectral reflectance is measured using, for example, an integrating sphere contact spectrophotometer. Measured using Sanderson's correction formula % formula %) (In the formula, Ro is the measured reflectance, kl is the external interface reflectance, R
2 is internal interface reflectance, Rω is intrinsic reflectance) Kubel force・
Munk's basic formula (where K is the absorption coefficient and S is the scattering coefficient) and Duncan's acid formula (where Ci is the pigment concentration of primary color i, Ki is the absorption coefficient of primary color i, and Si is the scattering coefficient of primary color i) , C, is the pigment concentration of the white pigment, K is the absorption coefficient of the white pigment, S is the scattering coefficient of the white pigment, (Ki5)ffiIX is the (K/ Using the scattering coefficient of white pigment 9·l, the values and S values of white, black, and each primary color are determined based on the relative two constant theory, and the pigment concentration of each primary color is converted into high-speed digital data as primary data. Enter the information into the computer, perform the first toning mix, create a toning plate, measure its spectral reflectance, and measure the color difference to confirm that the actual color difference with the sample plate is within the allowable range. If not, for example, calculate the tristimulus value from the reflectance of the sample of the first toning mixture, find the theoretical color difference with the sample, and set the color difference with the sample/X#0 as the additional concentration C of each pigment; The formula AC; = [TEDΦ]-, dX (where T is C
IE spectral tristimulus value matrix; E is the spectral distribution matrix of the illumination source; D is the differential coefficient (dRs/d(K/
S) s ) matrix; R5 is a vector of sample reflectance values; ΔX '' Xs - XM; Xg is a vector of sample tristimulus values (X, Y, Z'); ) to obtain a corrected formulation, then create a color toning plate, and actually measure the reflectance and color difference. By repeating this process until the color difference from the sample plate falls within the allowable range, the colored liquid is prepared. Therefore, when obtaining primary data for each primary color, it takes a long time to prepare the coated plate, and furthermore, it takes a long time to prepare the coated plate, perform spectral reflectance measurement,
The necessity of repeating calculations and the necessity of strictly controlling the coating plate manufacturing conditions were considered to be the biggest bottlenecks of color toning methods using the CCM method.

The problem to be solved by the invention is therefore a method of color matching a colored liquid to a sample color for which the spectral reflectance of the liquid film is known, which eliminates as much as possible the complicated process of producing a coated plate, and provides an easy method. There is a need for a method that can match colors within a short time, and it is an object of the present invention to meet this problem.

Means for Solving the Problems According to the present invention, the above object is achieved by forming a liquid film under predetermined conditions,
In addition, the spectral reflectance was measured with a non-contact spectrophotometer and CC
M (computer color matching) method is used to match the color of a colored liquid to a sample color for which the spectral reflectance of the liquid film is known.

In the case of paints, the hue of the colored liquid and the dried paint film are often different, and the hue also varies depending on the painting method, conditions for creating the dry paint film, etc., so color matching cannot be determined by the paint color on the paint plate. This has become semi-common sense, and little consideration has been given to performing strict color matching at the coloring liquid stage. Furthermore, most spectrophotometers are of the contact type, such as the integrating sphere type, and a non-contact measuring instrument with high precision has not yet been developed. The current situation is that almost no attempts have been made to measure it.

However, if the hue change between the colored liquid and the dry coated plate is accurately understood, it will be easy to predict the color match between the dried coated plates based on the color match between the colored liquids. Further, the reflectance of the colored liquid can be controlled by controlling the conditions to be constant, and the spectral reflectance can also be measured using a non-contact spectrophotometer.

In view of the above, as a result of research, the present inventors created a liquid film under certain conditions, measured the spectral reflectance with a non-contact spectrophotometer under certain conditions, and based on the existing dry CCM theory. When the colors of the colored liquids are matched by color matching between the colored liquids, it is possible to control the color difference between the dry coated plates within the allowable range, and it is possible to control the color difference between the dry coated plates within an acceptable range.
Made the important discovery that color matching by M was unnecessary.
We were able to complete the present invention.

That is, according to the present invention, the spectral reflectance measurement at the time of preparing the primary data of each primary color, the first mixed toning solution,
Spectral reflectance measurements of corrected blended toning liquids can be carried out in the liquid state without creating a dry coating plate. As already mentioned, the spectral reflectance of the colored liquid changes over time, so the conditions during measurement must be controlled to be constant. Therefore, in the present invention, it is essential that the liquid film be formed under predetermined conditions.

In one preferred embodiment of the invention, the liquid film is applied onto a suitable substrate such as art paper or tin plate using a doctor blade, bar coater, etc., manually or preferably using an automatic applicator, at a constant speed. It is produced by a method that creates a completely concealing coating film with a constant thickness. In another example, a rotating drum or a substrate may be immersed in a coating solution and then rotated or pulled up to form a liquid film on the drum or substrate. Furthermore, it is also possible to form a liquid film on the liquid surface in the paint tank.

In the present invention, the spectral reflectance of the liquid film thus obtained is measured using a non-contact spectrophotometer within a certain period of time after its preparation, for example within 20 seconds, 30 seconds or 1 minute. do. It is also possible to measure the spectral reflectance of the colored liquid through a sight glass provided on the tank wall.

As the non-contact spectrophotometer used in the present invention, a conventionally known fine sphere type spectrophotometer can be used without contact, but since the influence of ambient light is large, the light source must be made more powerful. It is necessary to devise measures such as Therefore, it is more preferable to use a light guide type non-contact spectrophotometer shown in FIG. 1 of the accompanying drawings. However, in a spectrophotometer that receives light without including the specularly reflected light from the sample, such as the light guide type spectrophotometer, CCM
The Sanderson correction formula in the basic theoretical formula is corrected by Ro = f (R) (in the formula, R is the measured reflectance by the same spectrophotometer, R8 is the measured reflectance to be applied to the Sanderson correction formula), It has been found by the inventors that this method should be applied. In the spectrophotometer shown in the attached figure, for example, a correction of Ro: 0.95R+0.05 is required. Furthermore, the light emitting and receiving conditions were changed to 45°.
, a 6-branch non-contact spectrophotometer with 6-direction illumination and 0° light reception can also be used.

The present inventors created a liquid film under predetermined conditions as described above.
We also discovered that wet color matching is possible by applying the normal dry CCM theory as is using spectral reflectance obtained using a non-contact spectrophotometer. In addition, an important finding has been obtained that by color matching the sample liquid and the blended liquid using the CCM method, the color difference between the sample color and the blended color on the dry coated plate can be controlled within an acceptable range.

Therefore, in the present invention, there is no need for a dry coating plate at all, neither when creating primary data for each primary color nor when measuring the spectral reflectance of compounded paints and modified compounded paints using Mana CCM. It can be operated in an extremely short time until measurement, and color matching of colored liquids can be performed extremely quickly and reliably in a short period of time.
This invention constitutes a useful invention in the field of producing colored liquids such as inks.

The present invention will be explained below with reference to Examples.

Example 1 An automatic applicator with a doctor blade with a nominal thickness of 20 mils was run at a constant speed to create a liquid film by applying the paint liquid onto art paper, and 20 seconds ± 1 second after painting, the first applicator was applied.
The spectral reflectance was determined using the non-contact spectrophotometer shown in the figure, and 8! Create membrane primary data.

Using the above primary colors, set a sample color in a total of 4 primary colors (white and 3 other primary colors), measure the liquid film of the set sample color, and CC
The primary formulation was determined using the M method.

The primary colors were prepared using the primary formulation obtained by the CCM method, and the liquid film of this sample was measured to determine the corrected formulation using the CCM method. Additional primary colors were blended using the resulting revised formulation.

The color difference between the sample color and the sample in the liquid film is FMCII color difference ΔE
CCM by additional mixing of primary colors and liquid film measurement was repeated until the result was within ≦0.5. When the FMCn color difference is within ΔE≦0.5, color matching is completed and the sample and sample colors are
Paint on art paper with a 0 mil doctor blade and heat at 90℃
After baking for 20 minutes, the color difference of the dried film was measured using a colorimeter.

The results are shown in Table 1.

Examples 2 to 6 A sample color was prepared from the primary color paint of Example 1 using the composition shown in Table 1, and color matching was performed in the same manner as in Example 1 to obtain a modified composition paint. We compared the color difference between dried paint plates.

The results are shown in Table 1.

[Brief explanation of the drawing]

1 is a side sectional view of a portion of a toroidal sensor of a preferred type of non-contact spectrophotometer used in carrying out the method of the present invention, and FIG. 2 is a bottom view thereof. In the figure, 1 is a light receiving part, 2 is an irradiation part, 3 is a cap, and a mirror inner wall part. patent application agent

Claims (4)

[Claims] (1) Create a liquid film under predetermined conditions, measure the spectral reflectance with a non-contact spectrophotometer, and use the CCM (computer color matching) method to compare the spectral reflectance of the liquid film to a known sample color. How to color match colored liquids. (2) The method according to claim 1, wherein the colored liquid is a paint liquid. (3) The method according to claim 1, wherein a liquid film is formed with a constant thickness on the substrate, and the spectral reflectance is measured within a certain period of time after the liquid film is formed. (4) The non-contact spectrophotometer is a type of spectrophotometer that can receive light without including specularly reflected light from the sample, and in the basic formula of CCM theory, Sanderson's correction formula is R_0=f(R) The method according to claim 1, wherein R is the measured reflectance and R_0 is the reflectance to be applied to the Sanderson correction formula.