JPS60198288A - Color image forming method - Google Patents

Abstract

PURPOSE:To enhance color forming property and ink-absorbing property and form clear images with high resolution, by using a recording material provided with a specified ink-receiving layer on a base, when forming color images by an ink jet recording method using a plurality of primary color recording liquids. CONSTITUTION:Color images are formed by the ink jet recording method while using a recording material provided with an ink-receiving layer (e.g., a layer comprising a particulate filler such as silica and a binder such as starch) having a Bekk smoothness of 20-120sec on a base (preferably, a paper).

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for forming a color image, more specifically, a method for forming a color image with excellent ink coloring properties by an inkjet recording method using a plurality of primary color recording liquids. Regarding the method.

[Prior art]

Writing with a pen has been common for a long time, but recently, so-called inkjet recording methods have also appeared, and recording liquids are also used here.

The inkjet recording method generates small ink droplets using various operating principles, and performs recording by flying them and adhering them to a recording material such as paper. It is attracting attention as a recording method that allows multicolor printing. Water-based recording liquids are mainly used for inkjet recording in terms of safety and printability.

As the recording material used in this inkjet recording method, conventional paper has generally been used. but,
As the performance of inkjet recording machines improves, such as faster recording and multicolor recording, recording materials for inkjet recording are also required to have more advanced properties.

In other words, the recording material for inkjet recording in order to obtain high resolution and high quality recording images must: 1) absorb ink as quickly as possible, and 3) ink should not flow into previous dots. Requirements include that the diameter of the ink dot should not be larger than necessary, 4) The shape of the ink dot should be close to a perfect circle and the surrounding area should be smooth, 5) The density of the ink dot should be high and the area around the dot should not be blurred. It is required that the performance is met.

Formation of a color image by the inkjet recording method is carried out by a so-called subtractive color mixing method in which recording is performed using a plurality of primary color inks. In this case, the primary color inks are generally cyan (C), magenta CM) and yellow (Y
) are used. The colors that can be expressed by mixing and recording these color inks on the same pixel are basically the following.

C+M-B (Blue) C+Y-G (Green) M+Y-R (Red) C+M+Y-+K (Black) Therefore, the colors represented by the three primary colors C, M, and Y are basically C, M, Y, and R. , G, B, and K, and a multicolor image made up of these seven colors is called a false color image.

In order to obtain a recorded image quality comparable to that of a color photograph using such a multicolor inkjet recording method, in addition to the above five required performances, the recording material must also have 6) high whiteness, and 7) coloring of the ink. 8) The ink absorbency is particularly excellent because the same number of small ink droplets as the number of ink colors may adhere to the same spot, etc. performance is weighted and required.

However, the reality is that a recording material that satisfies all of these required performances has not yet been found. For example, JP-A-52
The inkjet recording paper described in No. 74,304 absorbs ink quickly, but has the drawbacks that the dot diameter tends to become large, the periphery of the dots tends to blur, and the size of the paper changes significantly after recording. are doing.

[Purpose of the invention]

An object of the present invention is to provide a method for forming a color image using an inkjet recording method, which has particularly high ink absorption and excellent color development.

The above and other objects are achieved by the invention as follows.

[Disclosure of the invention]

That is, the method for forming a color image of the present invention is a method in which small droplets are formed using a plurality of types of color recording liquids having different colors, and the small droplets are attached to a recording material to form a color image. As the recording material, an ink receiving layer is provided on a support, and the Bekk smoothness of the ink receiving layer is
It is characterized by using a period within a range of 20 seconds or more and 120 seconds or less.

The recording material used in the method of forming a color image of the present invention has a unique surface state of the ink-receiving layer with a Bekk smoothness in the range of 20 seconds to 120 seconds, and this is more specifically 1, for example, has a structure in which relatively large amorphous filler particles, which are the main component of the ink-receiving layer, are randomly placed and appear on the surface of the coating layer,
This means that the filler particles have a structure in which a large number of large voids functioning as ink absorption holes are scattered among them, and the surface state is typically shown in FIG. 1. Of course, these filler particles appearing on the surface are also fixed within the ink-receiving layer by the binder and do not easily separate from the ink-receiving layer. Figure 1 is a scanning electron micrograph of the surface of the ink-receiving layer of the recording material used in the method of the present invention, magnified approximately 1,500 times, and shows a certain level of smoothness that can be expressed as having debris of various sizes scattered. The surface condition of the ink-receiving layer is clearly shown.

On the other hand, FIG. 2 is an electron micrograph at the same magnification of the surface of a recording material having a conventional ink receiving layer. The surface of this recording material has a surface structure with many fine pores that serve as ink absorption holes and a palm-shaped ink hole layer, and the Bekk smoothness value is large, and the method of the present invention It is clearly distinguished from the recording material used for.

As described above, on the surface of the ink-receiving layer of the recording material used in the method of the present invention, there are large and numerous voids between filler particles that serve as ink-absorbing pores. The ink is quickly absorbed into the gaps between the filler particles, and the absorption capacity for color ink is also large.

If the Beck smoothness value of the ink receiving layer of the recording material is less than 20 seconds, the ink absorbency is insufficient, while if the Beck smoothness value exceeds 120 seconds, the ink absorbency is good. However, the resolution of the recorded image decreases.

As the support for the recording material used in the method of the present invention, it is appropriate to use paper, but cloth, resin film, synthetic paper, etc. can also be used.

On the other hand, the ink receiving layer of the recording material used in the method of the present invention is basically composed of filler particles and a binder. Examples of the filler particles include silica, clay, talc,
White amorphous inorganic pigments such as diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, aluminum silicate, lithopone, alumina, and zeolite; organic powders such as ion exchange resin powder and plastic pigments are mentioned, and these 1
More than one species is used. The irregular shape of the filler particles appears on the surface of the ink-receiving layer like scattered rubble, and in order for the ink-receiving layer to have a certain Bekk smoothness, the particle size of the filler particles used must be 1 to 1. It is desirable that the thickness be about 30μ, more preferably about 3 to 20μ. If the particle size of the filler particles is too large, the roundness of the ink dots will be impaired and the resolution of the recorded image will be reduced, which is not preferable. The higher the dye adsorption ability of the filler particles, the more preferable they are, and it is more preferable that they have a porous structure. This is because the color development is better when the pigment in the ink absorbed into the gaps between the filler particles is captured in the outermost layer of the ink-receiving layer.

On the other hand, the binder includes water-soluble polymers such as starch, gelatin, casein, gum arabic, sodium alginate, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, and polyacrylamide; synthesis of synthetic rubber latex, etc. Examples include organic solvent-soluble resins such as resin latex, polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide resin, phenol resin, polyurethane resin, and alkyd resin. Further, various additives such as a dispersant, a fluorescent dye, a PH adjuster, an antifoaming agent, a lubricant, a preservative, and a surfactant can be mixed in the ink-receiving layer.

The recording material used in the method of the present invention can be prepared by dispersing these ink-receiving layer components in a medium such as water and preparing a coating liquid using a roll coating method, a rod bar coating method, a spray coating method, or an air kino 71-1 method. − / ・ノ)
i"If 纺1-hiL1古+k !* L-1-= It is produced by removing the coating and then drying it as soon as possible. The mixing ratio of filler particles and binder in the coating liquid is Generally, the amount of binder is 10 to 10 parts by weight per 100 parts by weight of filler particles.
0 parts by weight is appropriate, and when the average particle size of the filler particles is large, good results are obtained by using as little amount of binder as possible. The amount of the ink receiving layer on the support is usually about 1 to 50 g/lri' (dry coating amount). Further, it is preferable to apply the coating at about 2 to 30 g/m' (dry coating amount).

On the other hand, the color ink used in the method of the present invention consists of a recording agent such as a dye and a liquid medium component, and the liquid medium component is
It is desirable to use not only water alone but also a mixture of water and various water-soluble organic solvents.

Examples of the water-soluble organic solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, '5e
c-butyl alcohol, tert-butyl alcohol,
Alkyl alcohols having 1 to 4 carbon atoms such as isobutyl alcohol Amides such as dimethylformamide and dimethylacetamide; Ketones or ketone alcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; polyethylene glycol, Polyalkylene glycols such as polypropylene glycol; alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, 1,2,6-hexandriol, thiosyglycol, hexylene glycol, diethylene glycol, etc. Glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether.

Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether are preferred. Polyhydric alcohols are particularly preferred because they are highly effective as wetting agents to prevent nozzle clogging caused by evaporation of water in color ink and precipitation of recording material.

In order to adjust the surface tension of color ink containing such liquid medium components within an appropriate range, various cationic, anionic or nonionic surfactants, jetanolamine,
Surface tension modifiers such as triethanolamine can be added.

A solubilizer can also be added to the color ink. Typical solubilizers are nitrogen-containing heterocyclic ketones, and their intended action is to dramatically improve the solubility of the recording liquid in the liquid medium.

For example, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferably used.

Color inks prepared from these components have their own recording properties (signal response, stability of droplet formation, ejection stability, long-term continuous recording performance, ejection stability after a long period of recording cessation). ), it has excellent storage stability and fixability to recording materials, but in order to further improve these properties, various additives may be added to it. Examples include viscosity modifiers such as polyvinyl alcohol, celluloses, water-soluble resins, etc., and PH modifiers using buffer solutions.

Further, in order to prepare color inks used in inkjet recording methods of the type in which the ink is charged, resistivity adjusters such as inorganic salts such as lithium chloride, ammonium chloride, and sodium chloride are added. Note that when applied to an inkjet method in which ink is ejected by the action of thermal energy, thermal physical property values (eg, specific heat, coefficient of thermal expansion, thermal conductivity, etc.) may be adjusted.

The color ink used when forming a color image according to the method of the present invention consists of the above-mentioned components, and includes the above-mentioned cyan (C), magenta CM) and yellow (CM).
In addition to these, black or other intermediate color inks may be appropriately used depending on the hue of the color image which is the three primary colors of Y).

C Effects of the present invention] When a color image is formed by an inkjet recording method using a plurality of primary color recording liquids, a recording material having an ink receiving layer having a specific Bekk smoothness provided on such a support can be used. By using this material, even if recording liquids of different colors overlap in the same area within a short period of time, there is no phenomenon of recording liquid flowing out or seeping out, resulting in high resolution, clarity, and excellent color development properties. This has made it possible to form images with recording quality comparable to that of color photographs.

〔Example〕

Hereinafter, the present invention will be explained in more detail according to Examples.

Production Example 1 Silica (Thyroid 620, quotient 1”+
l' is lost: H: +'J'1% l++) W, /↓-1) Senshi 171 1 umbrella ~ 14X: 2Q) tm) and calcium carbonate (average particle size: 2u), An ink-receiving layer coating composition was prepared based on the following composition using polyvinyl alcohol and SBR latex as a binder.

Silica 100 parts by weight Calcium carbonate 15 tt Polyvinyl alcohol 301/SBR latex 3 Water 500/1 On the other hand, as a support, general high-quality paper (basis weight 65 g/rn') with a sizing degree of 35 seconds based on JIS P8122 was used. The above-mentioned coating composition was coated onto this support by a blade coater method at a dry coating weight of 10 g/m', and dried by a conventional method to obtain a recording material.

FIG. 1 shows a scanning electron micrograph of the surface of the ink-receiving layer of the obtained recording material at a magnification of about 1500 times. The Bekk smoothness value of this recording material was 108 seconds. The Bekk smoothness was measured using an Oken air permeability smoothness tester (Asahi Seiko ■Ml).

Production Example 2 Using diatomaceous earth (Cerai 281° trade name, Johnmanviric acid, average particle diameter = 8 scales) as filler particles and starch and SBR latex as binders, an ink was produced based on the following composition. A composition for coating a receptor layer was prepared.

Diatom ± 100 Parts by weight Starch 3Q tt SBl'l Latex IQ tt Wood 800 tt On the other hand, as a support, the same general high-quality paper as in Production Example 1 was used, and the above coating composition was dried and coated on this support. Effort 1
It was coated by a bar coater method at a ratio of 0 g/m' and dried by a conventional method to obtain a recording material. The Bekk smoothness value of this recording material was 28 seconds.

Production Example 3 Using zeolite (average particle diameter = 10 scales) and talc (average particle diameter: 7 scales) as filler particles and casein as a binder, a coating composition was produced based on the following composition. .

Zeolite 100 parts by weight Talc 1O7/Casein 20 tt Water 500 tt On the other hand, as a support, the same general high-quality paper as in Production Example 1 was used, and the above coating composition was applied onto this support in a dry coating amount of 1
It was coated at a rate of 5 g/m' by a bar coater method and dried by a conventional method to obtain a recording material. The Bekk smoothness value of this recording material was 60 seconds.

Reference Example 1 Commercially available art coated paper (product name: SK
A scanning electron micrograph of the surface of the ink-receiving layer of Coat (manufactured by Yamaba Kokusaku Pulp ■) at a magnification of about 1,500 times was as shown in FIG. The Bekk smoothness value of this recording material is 1200.
It was seconds.

Comparative Production Example 1 Calcium carbonate (average particle size: 50J) as filler particles
L11) was used to prepare polyvinyl aluminum as a binder.

Calcium charcoal 100 Parts by weight Polyvinyl alcohol 20 // Water 500 On the other hand, as a support, the same general high-quality paper as in Production Example 1 was used, and the above coating composition was applied on this support in a dry coating amount of 1
It was coated by a bar coater method at a rate of 5 g/rn' and dried by a conventional method to obtain a recording material. The benchmark smoothness value of this recording material was 10 seconds.

Examples 1 to 3 and Comparative Example 1.2 The same color image was produced by inkjet recording using the following four color inks on the breeding recording materials prepared in the above production examples, reference examples, and comparative production examples. The characteristics of the recorded images were evaluated.

Yellow ink (composition) C, 1, acid yellow 23 2 parts by weight diethylene glycol 3o// Magenta ink (composition) [:, 1. Acid Red 92 2 Parts by weight diethylene glycol 3Q tt Water 7Q tt Cyan ink (composition) C, 1, Direct Blue 86 2 Parts by weight diethylene glycol 301/ Water 701/ Black ink (composition) C, 1, Direct Black 192 Parts by weight diethylene glycol 3011 Water 7Q tt Table 1 shows the evaluation results for the obtained color images.

Note that the characteristics of the recorded images were evaluated based on the following criteria.

1) The dot density was measured using a Sakura microdensitometer PDM-5 (manufactured by Konishiroku Photo Industry ■) using a printed dot.

2) The dot shape is determined by observing the printed dots with a stereoscopic microscope.
The amorphous one was designated as X.

3) The degree of bleeding was determined by measuring the diameter of a printed dot using a stereomicroscope, and expressed by how many times larger the diameter of the printed dot was than that of an ink droplet.

4) Color vividness was determined by visually comparing the color vividness of the inkjet recorded images, and the best one was ranked as ■, the worst as ×, and ranked as ■, O1△, and ×.

5) Ink absorption was evaluated as O for areas where four colors of ink were overlaid and the image was clear without any ink running out, and as Bad for other areas.

Note that in Table 1, the colors shown within the brackets in the evaluation column for each image characteristic are the colors of the primary color inks that were evaluated.

[Brief explanation of drawings]

FIG. 1 is a scanning electron micrograph of the surface of the ink-receiving layer of the recording material used in the method of the present invention, magnified approximately 1500 times;
FIG. 2 is an electron micrograph at the same magnification of the surface of commercially available art coated paper. Patent Applicant Canon Co., Ltd. Procedural Amendment (Method) April 23, 1985 Commissioner of the Patent Office 1, Indication of Case 1988 Patent Application No. 157893
No. 2, Name of the invention Method for forming a color image 3, Relationship with the person making the amendment Applicant: Canon Co., Ltd. 4: Agent address: 1-9-20-5 Akasaka, Minato-ku, Tokyo, Nikkan Showa of the amendment order March 26, 1960: Shipping date 7, page 22, lines 2 to 5 of the statement of contents of the amendment was changed to ``Figure 1 shows the surface of the ink-receiving layer of the recording material used in the method of the present invention. This is a photograph substituted for a drawing taken with a scanning electron microscope at approximately 1500x magnification showing the shape and arrangement of filler particles, and Figure 2 is a photograph taken at the same magnification showing the shape and arrangement of filler particles on the surface of commercially available art coated paper. This is a photograph taken in place of a drawing taken using an electron microscope.''

Claims (1)

[Claims] 1. A method for forming a color image by forming small droplets using multiple types of color recording liquids of different colors and adhering the small droplets to a recording material, the method comprising: . A method for forming a color image, characterized in that a support is provided with an ink-receiving layer, and the Bekk smoothness of the ink-receiving layer is within a range of 20 seconds or more and 120 seconds or less.