JP2002254680A - Image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording method for offering an excellent image which is approximately equal to printed matter in high density and high image quality, and reduces variation in color. SOLUTION: A color ink jet using ink having at least four colors composed of yellow, magenta, cyan and black is used for the image recording method, which is characterized in that respective hue ranges of red, green and blue, to be formed by using at least two colors of ink, are in fixed hue ranges on a recording medium. In the at least two colors of ink, chromaticity indices a* and b* on the recording medium fall within the fixed hue ranges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording method using a color ink jet having high density, high image quality, and little color fluctuation similar to a printed matter.

[0002]

2. Description of the Related Art In recent years, an ink jet recording method is a method of recording images and characters by causing minute droplets of ink to fly from minute nozzles based on various operating principles and adhere to a recording sheet such as paper. It has features such as high speed, low noise, easy colorization and low cost, and is currently used in various fields as various image recording devices, such as various printers, facsimile machines and computer terminals. .

Further, by using a plurality of ink nozzles, it is easy to perform multicolor recording. An image formed by the full-color ink jet recording method can obtain an image close to multicolor printing or color printing by a plate making method in a short time and at low cost.

In the ink jet recording method, a dye-based ink is often used from the viewpoints of ink ejection properties, maintenance, and the like.
It is difficult to reproduce colors when trying to produce an image similar to a printed matter using pigment ink, and there is a problem in that even if the three primary colors of yellow, magenta, and cyan are combined, the color reproduction accuracy is reduced in a mixed color portion.

In recent years, an ink jet recording system using a pigment ink has been developed, but since the image forming method is different from that of a printed matter, the color reproduction accuracy of a mixed color portion is difficult.

Further, in order to obtain a high-quality image similar to such a printed matter, it is required that the density of print dots is high, the color tone is bright and vivid, and the like. However, in order to obtain a high density, it is necessary to discharge a large amount of ink or to mix several types of colors to reproduce more colors, but in this case, the ink overflows or bleeds, and the image quality is reduced. It is expected that there will be a problem that the color will decrease and that the time required for fixing the ink will be long and the hue change will be large immediately after the ejection.

[0007]

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above circumstances, and provides an image recording method for providing an excellent image having high density, high image quality and little color fluctuation similar to a printed matter. To provide.

[0008]

The above object of the present invention has been attained by the following constitutions.

1. In an image recording method using a color ink jet using at least four color inks of yellow, magenta, cyan and black, the perceived chromaticity indices a ^* and b ^* on the recording medium have a hue range [CIE1976].
^{(L *, a *, b} *) respectively in the space] ^{Yellow: a * = -15~5, b *} = 80~95 ^{Magenta: a * = 65~80, b *} = -15~5 Cyan: a ^* = −50 to −30, b ^* = − 53 to −38 The hue ranges of red, green, and blue formed using two or more colors of ink are as follows on a recording medium. Image recording method.

Red: a ^* = 55 to 70, b ^* = 33 to 48 Green: a ^* = − 80 to −65, b ^* = 15 to 30 Blue: a ^* = 10 to 25, b ^* = − 55 -40 2. In an image recording method by color ink jet using at least four color inks of yellow, magenta, cyan and black, the total ejection amount of ink is 1 to 80% of the maximum amount absorbed per unit area of a recording medium.
, The perceived chromaticity indices a ^* and b ^* on the recording medium
But hue range ^{[CIE1976 (L *, a *} , b *) space], respectively, in ^{yellow: a * = -15~5, b *} = 80~95 ^{Magenta: a * = 65~80, b *} = -15 -5 cyan: a ^* = − 50 to −30, b ^* = − 53 to −38 The hue ranges of red, green and blue formed by using two or more colors of ink are as follows on a recording medium. An image recording method, characterized in that:

Red: a ^* = 55 to 70, b ^* = 33 to 48 Green: a ^* = − 80 to −65, b ^* = 15 to 30 Blue: a ^* = 10 to 25, b ^* = − 55 -40 3. The average solid content of the dyes in the plurality of inks is 3 to 20% by mass.
3. The image recording method according to the above item 1 or 2, wherein

Hereinafter, the present invention will be described with reference to preferred embodiments. The features of the present invention are yellow, cyan,
By using a combination of basic inks of magenta and black, a color image similar to a printed matter is formed on various recording media. When obtaining a high-resolution image, it is more preferable to prepare each color separately in dark and light colors.

The dye ink and pigment ink used in the present invention are not particularly limited as long as they satisfy the above a ^* value and b ^* value.

In the present invention, as a medium for dissolving or dispersing a dye or a pigment, a medium used in a conventional ink jet system can be used, and water or an organic solvent or a mixture of water and an organic solvent is appropriately selected depending on the dye and the pigment. it can. The solid content of the dye and the pigment in the ink is preferably in the range of 1 to 30% by mass relative to the total amount of the ink, and more preferably 3 to 20% by mass from the viewpoint of color fluctuation and drying property described later.

In the ink, various dispersants, surfactants, viscosity modifiers, surface tension regulators, pH regulators, conductivity regulators, drying inhibitors, dyeing improvers, jetting improvers, etc. Is added as needed.

As for the chromaticity of each color of the above-mentioned ink, the perceived chromaticity indices a ^* and b ^* of the recorded matter when the recording medium is ejected at about ² to 40 ml / m ² have a hue range [CIE 19
76 (L ^* , a ^* , b ^* ) space] respectively.

If the upper and lower limits of the color reproduction range of yellow, magenta and cyan are within this range, when red, green and blue are reproduced by mixing two or more colors of yellow, magenta and cyan, they are close to the printed matter. Preferred color reproducibility is obtained.

The recording medium used in the present invention is not particularly limited as long as the recording medium can accept the above-mentioned ink. Good results are obtained.

The ink-jet recording method and apparatus used in the present invention may be any of conventionally known ones. For example, a method in which a recording signal is applied to ink in a chamber of a recording head by applying thermal energy corresponding to the recording signal and droplets are generated by the thermal energy. And a method and an apparatus for ejecting liquid droplets using vibration of an apparatus or a piezo element.

In another preferred embodiment of the present invention, each chromaticity is reproduced when the total amount of ink applied is 1 to 80% of the maximum amount absorbed per unit area of the recording medium. It is. If the ink ejection amount is more than 80%, depending on the recording medium, drying may not be sufficient and the handleability may deteriorate, or the fluctuation from the initial chromaticity may increase. Become a target.

The amount of absorption of a recording medium is described in, for example, TAPP
I pulp test method No. It can be measured using a Bristow tester based on the liquid absorption test method (Bristow method) of paper and paperboard of Nos. 51 to 87.

In the present invention, the contact time measured by this method is 5
The amount of transfer per second was taken as the maximum absorption of the recording medium.

When the ejection amount is limited, the color reproduction range may be narrowed. In this case, the ejection amount is limited by setting the solid concentration of each ink to 3% by mass or more on average. However, a desired color reproduction range is secured.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 The titanium dioxide-containing side of an 80 g / m ² paper support coated with polyethylene on both sides (thickness 130 μm, containing 7% titanium dioxide in the polyethylene layer on the ink receiving layer side) Was coated with a gelatin subbing layer having a thickness of 0.1 g / m ² , and the following coating solution for an ink receiving layer was applied thereon. The recording medium was coated with a coating solution on a support using a wire bar, and then cooled and set at about 5 ° C. for about 20 seconds.
It dried with the warm air of ° C, and produced the recording medium for inkjet.

The used amount of each material indicates the amount per 1 m ² of the recording medium, “%” indicates “% by mass”, and “part” indicates “part by mass”.

<Ink receiving layer coating liquid> 100 g of silica powder having an average particle diameter of 2 μm, 5 g of alkali-treated gelatin, and 0.2 g of a surfactant were made up to 10,000 ml with pure water, and then 2,000 rpm using a sand grinder. It was added as a silica dispersion obtained by dispersing for 1 hour. Phthalized gelatin (phthalation degree: 88%) 6.8 g Polyvinyl alcohol (PVA105: manufactured by Kuraray Co., Ltd.) 9.2 g Silica 2.0 g Surfactant 0.004 g At this time, the absorption amount of the recording medium determined by the Bristow method is as follows: It was 38 ml / m ² .

<Ink Composition> Each ink composition was prepared with the following composition.

(Yellow ink) C.I. I. 29025 0.88 parts C.I. I. 22910 4.55 parts Zeneca Proxel GXL (D) 0.1% Ethylene glycol 50 parts Deionized water balance (magenta ink) C.I. I. 18134 2.55 parts Proxel GXL (D) 0.1% Ethylene glycol 50 parts Deionized water balance (cyan ink) I. 74220 3.69 parts Proxel GXL (D) 0.1% Ethylene glycol 50 parts Deionized water balance (black ink) I. 29025 0.07 parts C.I. I. 22910 0.36 parts C.I. I. 18134 0.94 parts K ink 4.85 parts Zeneca Proxel GXL (D) 0.1% ethylene glycol 50 parts Deionized water Remainder The number of discharge nozzles = 64, nozzle diameter = 24 μm, discharge frequency = 30 kHz An image was formed on the inkjet recording medium with a printer using the ink composition.

UCR is used to reproduce the color of the original image using a color chart included in high-definition color digital standard image data (published by the Japan Standards Association).
A color conversion process was performed to add a color conversion filter. At this time, the total ink ejection amount was 30 ml /
The color chart was output through a color conversion filter as m ^{2 and} dried at a temperature of 65 ° C. for 10 minutes.

The solid images L ^* , a ^* , b of yellow, magenta, cyan, red, green, and blue of the obtained image
^{* The} value is Gretag Macbeth's Spect
It was measured with a D50 light source and a viewing angle of 2 ° using rolino, and compared with JapanColor97 standard printed matter, an image similar to the printed matter could be obtained with color reproducibility close to the print level. The results are shown in Table 1.

Example 2 An image was produced in the same manner using the above ink composition using IJPM-H (manufactured by Kimoto) as a recording medium, and the same evaluation as in Example 1 was performed. Images were obtained. The results are shown in Table 1.

Comparative Example Using an ink jet printer PM9000C manufactured by Epson, an image was similarly formed on an IJPM-H (manufactured by Kimoto), and yellow, magenta, cyan, red, green,
The L ^* , a ^* , and b ^* of the solid blue portion were measured, evaluated in the same manner as in Example 1, and compared in the same manner. However, the L ^* , a ^* , and b ^* values departed from the print level. Only a sample having a color distinctly different from that of the printed matter was visually obtained. Table 1 shows the L ^* , a ^* , and b ^* values of the obtained image and JapanColor97 standard printed matter.

[0034]

[Table 1]

[0035]

According to the present invention, it is possible to provide an image recording method which provides an excellent image having high density, high image quality and little color fluctuation similar to a printed matter.

Claims (3)

[Claims] 1. at least yellow, magenta, cyan
Ink using four colors of black and black ink
In an image recording method using a computer, information on a recording medium
Chromaticity index a^*And b^*Is the hue range [CIE1976
(L^*, A^*, B ^*) Space] yellow: a^*= -15 to 5, b^*= 80-95 Magenta: a^*= 65-80, b^*= -15 to 5 cyan: a^*= -50 to -30, b^*= -53 to -38, two or more inks are used.
And blue hue ranges on the recording medium
An image recording method characterized by being below. Red: a^*= 55-70, b^*= 33-48 Green: a^*= -80 to -65, b^*= 15-30 Blue: a^*= 10 to 25, b^*= -55 to -40 2. An image recording method by color ink jet using at least four color inks of yellow, magenta, cyan and black, wherein the total amount of ink applied is one of the maximum amount absorbed per unit area of a recording medium. When it is ８０80%, the perceived chromaticity indices a ^* and b ^* on the recording medium are in the hue range [CIE1976 (L ^* , a ^* ,
b ^*) respectively in the space] ^{Yellow: a * = -15~5, b *} = 80~95 ^{Magenta: a * = 65~80, b *} = -15~5 Cyan: a ^* = -50~-30, An image recording method, wherein the hue ranges of red, green, and blue formed by using two or more inks in which b ^* = − 53 to −38 are respectively below on a recording medium. Red: a ^* = 55-70, b ^* = 33-48 Green: a ^* =-80--65, b ^* = 15-30 Blue: a ^* = 10-25, b ^* =-55-40 3. The ink according to claim 1, wherein the average solid content of the dyes is 3 to 3.
3. The image recording method according to claim 1, wherein the content is 20% by mass.