JPS58136482A - Ink jet recording method - Google Patents

Abstract

PURPOSE:To obtain a recording sheet capable of recording a high-quality image thereon and resistant to water, by a method wherein an image is recorded by ink jet recording on a recording sheet provided with a porous resin layer as an ink-receiving part, and then the surface of the resin layer is melted to become transparent. CONSTITUTION:The porous resin layer 1 is produced, for example, by a method wherein a resin capable of being formed into a film is kneaded with a pore- generating source substance (a substance capable of foaming by the heat or light, a water-soluble inorganic salt or the like) dispersed uniformly or locally therein, is molded, and then pores are generated in the molded material by heating, irradiating with light or immersing in water. After recording an image by ink jet recording on the recording sheet provided with the porous resin layer 1 as an ink-receiving part, a surface region of the resin layer 1 is melted by an appropriate heating means and an appropriate pressing means so that the resin becomes transparent.

Description

[Detailed description of the invention] The present invention is an inkjet recording method.

This invention relates to a method for improving multicolor inkjet recording.

The inkjet distribution method uses various types of ejection methods (for example, an electrostatic suction method, a method that uses a piezoelectric element to give the ink a suction-like vibration or displacement, and a method that heats the ink to make it foam. Methods using pressure, etc. are known.

)K, forming an ink droplet,
Recording is performed by attaching some or all of them to a recording material such as paper (abbreviated as recording paper).

In this way, when recording using liquid ink, -
It is necessary that the ink does not bleed onto the surface of the recording paper and cause the print to become blurry; 1. It is also necessary that the ink dries as quickly as possible after the ink is written, and that the paper surface is not accidentally contaminated; It is desirable that the pigment in the ink fixed on the recording paper does not discolor.And, especially in multicolor inkjet recording using two or more different colored inks, ■Absorption of ink onto the recording paper is desirable. Even if there are overlapping ink dots of different colors due to rapid printing, make sure that the ink that adheres later does not heat up with the ink that adhered earlier, or that the ink dots are glued), or that the ink dots do not flow out. ■ The shape of the ink dot must be close to a perfect circle and the surrounding area must be smooth; ■ The ink dot must be of high purity and the area around the dot must not be damaged. , ■ The color of the recording paper is white and the contrast with the ink dots is large; ■ The color of the ink does not change depending on the type of recording paper; ■ The dimensional changes of the recording paper (e.g., wrinkles, spread) are not noted.
It is necessary to satisfy various requirements such as IItII and less later.However, in the past, in order to satisfy these requirements, it is often the case that a great deal depends on the characteristics of the recording paper used. However, in reality, no matter what type of paper is used, whether it is paper or coated paper, it is still difficult to meet the demands mentioned above. With plain paper that has been nized, the ink can be prevented from spreading in the direction of the paper surface and causing "bleeding", but on the other hand, the ink absorption becomes worse and the time required for ink electrodeposition becomes longer. When there is overlap between the two inks, inks of different colors may be mixed, resulting in inconveniences such as unnecessary enlargement and disturbance of ink dots.

Also, in view of these inconveniences, coated paper in which a hydrophilic resin paint is applied to the surface of the base paper has been proposed.

However, with such coated paper, the degree of penetration of the dye in the ink becomes too large, causing the dots to deteriorate), and the ink absorbency becomes excessive, causing the ink dots to become large. 9, the dot periphery is blurred, and the shape and dimensions of the paper change greatly due to moisture absorption (P4). Also, with this coated paper, the recording quality deteriorates due to the peeling of the coating material from the base paper. However, there are disadvantages such as the fact that it is technically very difficult to provide a coating layer with uniform physical properties on the surface of the recording paper. Therefore, the main purpose of the present invention is to satisfy all the nine problems that the prior art could not solve in the above technology WIK.In particular, in the present invention, a plurality of The purpose is to satisfy almost all of the requirements stated above in recording 9 (full) colors using color ink.

In particular, in the inkjet recording method of the present invention that achieves the above object, inkjet recording is performed on a recording material having a porous resin layer as an ink receiving part, and at least the surface of the resin layer is melted after death. It is characterized by being more transparent than K.

Hereinafter, the present invention will be explained in detail with reference to illustrated examples and examples.

1 to 3 are schematic cross-sectional views for outlining examples of the structure of recording paper used in the present invention, and in FIG. 1,
1 is a porous resin layer (including a film), 2 is a resin layer (including a film) made of the same material as the porous resin layer 1, and 3 is a substrate, such as paper, cloth, Consists of liquid-absorbing porous materials such as porous resins and wood, and non-liquid-absorbing materials such as resins and metals.Which of these materials is actually selected as the base 3 must be recorded. (depending on purpose and use)

In the present invention, as the resin constituting the porous resin layer 1 and the resin layer 2, any water-soluble or organic solvent-soluble resin that can be formed into a film can be used. For example, as a water-soluble resin Examples of organic solvent-soluble resins include polyvinyl alcohol, starch, casein, gum arabic, gelatin, polyacrylamide, carboxymethylcellulose, sodium polyacrylate, and sodium alginate. Examples of organic solvent-soluble resins include polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, and polyvinyl chloride. Examples include acrylonitrile, polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide resin, phenol resin, polyurethane resin, and alkyd resin.

When ceramics, especially water-soluble resins, are used, problems such as deformation due to moisture absorption and excessive ink removal may occur, so the resin layer 1.2 is further treated to make it waterproof. may also be applied.

In the present invention, the method for creating the porous resin layer 1 is as follows: (1) A substance that foams when exposed to heat and light is added to the resin and kneaded to form a round object (film formation), which is then heated or exposed to light. A method in which fine pores are formed by air bubbles in a resin layer by irradiation. ■ After molding (film formation) a resin in which fine particles of water-soluble inorganic salts (e.g., sodium chloride) are dispersed, it is immersed in water. A method in which the inorganic salts are eluted in water to form moldy pores in the tree matrix. (2) Fine particles of zeolites, silica, diatomaceous earth, etc. are dispersed in the resin to form nine methods. There is a method of 1M (film formation) and then immersing it in an acidic aqueous solution to elute the fine particles and form moldy pores in the resin matrix. As the resin of
Any substance that cannot be dissolved in at least an aqueous solution or an acidic aqueous solution will be destroyed.

For reference, examples of resins suitable for these methods are listed below.

Examples include polyvinyl chloride, polystyrene, polyacrylonitrile, polyvinyl acetate, cellulose acetate, polyvinyl butyral, acrylic resin, polyamide resin, styrene-butadiene latex, alkyd resin, polyvinyl alcohol, polyester resin, and copolymers thereof. .

Furthermore, opaque agents for these resins can also be added; examples thereof include diptyl phthalate, dioctyl adipate, polyester, ethylene glycol, chlorinated paraffin, and the like.

By the way, when the recording paper is composed of only the porous resin layer 1 as shown in Fig. 1, it is better to make the thickness as thick as possible (approximately several millimeters K) in order to increase the amount of ink absorbed. .

In addition, when the recording paper is configured as shown in Figure 2, the above
In method (2), one side K, pores (
Additionally, to construct the recording paper shown in Figure 3, it is necessary to separately form and remove porosity (generally with a thickness of 5 to 50 degrees). The resin layer l is attached to at least one side (or both sides are acceptable) of any substrate 3.The nine-porous resin layer IKti formed as described above has a large number of holes (not shown). They are randomly arranged three-dimensionally in close proximity to each other, and in many cases, multiple holes communicate with each other to form a through hole.The size of these holes is large enough that capillary force acts on them. It is preferable to set the temperature in the range of several hundred to several microns.

Further, the shape of the hole is not limited to III/lK. In the present invention, the size and shape of these pores can be adjusted as desired within the above range by adjusting or controlling the manufacturing and processing conditions after film formation of the resin matrix before making it porous. It can be changed to ◎KJ! When the resin layer IK ink described above adheres, the pigment (for example, dye) in the ink is selectively adsorbed to and captured by the resin part of the resin layer 1, while the solvent in the ink is It is absorbed into the pores by capillary action, etc. In this way, in the present invention, when the dye in the ink is captured on the outermost surface area of the recording paper, the coloring properties are extremely good. Since the pressure is quickly transferred to the lower layer side, for example, the substrate side, through the ink dots, an apparent dry state can be quickly obtained on the surface of the recording paper. In order to ensure that the ink dots do not become larger than necessary on the recording paper, and that the density of the ink dots is high and the periphery of the dots is not blurred, the occupancy (volume) ratio of the pores in the resin layer 1 is important. has a huge impact. Like this 1.
For these reasons, in the present invention, it is undesirable that the pore occupancy rate is extremely reduced or, conversely, that the pore occupancy rate is extremely increased.

In other words, in the former case, the absorbency of the ink crystallizes,
There is a drawback that the time required for fixing the ink increases. Moreover, in the latter case, the amount of ink transferred to the substrate side increases, resulting in the phenomenon of so-called ink bleed-out and deterioration of the dot shape. Therefore, it is desirable to avoid these aspects in the present invention.Next, in the present invention, at least the surface layer region of the resin layer 1 is formed by performing IK inkjet recording on the above-mentioned porous resin layer. The lji image density can be further improved by making it transparent by hot melting it (that is, melting it). Also, at this time, since the openings on the surface of the resin layer 1 are closed, moisture absorption (
The water resistance decreases and the water resistance of the recording paper also improves. When melting the porous resin layer 1, various heating means and pressure means are used. For example, various dryers, hot plates, heat rollers, irons, etc. are used. Also, as pressure means, for example, various calender roller pairs, press machines, etc. are used.Of course, these heating means and It may be used in combination with a pressure means.Here, more detailed examples will be explained and the effects of the present invention will be illustrated.

″・, Example 1 ◆Recording paper preparation example Sample A 5ON amount of acrylic resin 10 parts by weight of titluene solution (SKY-1 manufactured by Toagosei Kagaku Co., Ltd.), 60 parts by weight of methyl ethyl ketone, 13Xm synthetic zeolite (U, C, C
Mix 30 parts by weight of 1 μ particles of Molecule 1 Lar Sheep 13x) manufactured by Company 0, pulverize and mix in a ball mill for 3 days. The dried O2 film was peeled off from the stainless steel plate, and the film was immersed in a citric acid aqueous solution adjusted to pH 3 for 2 minutes, washed with water, and dried to obtain an opaque porous film sheet. - 10 parts by weight of luene solution (SKY-1 manufactured by Toagosei Kagaku Co., Ltd.) and 6011 til of methyl ethyl ketone. , 13X11 synthetic zeolite)
(U, C, C, manufactured by Molecular Sheep 13X) 1μ
30 weight tS particles were mixed and pulverized and mixed in a ball mill for 3 days.The resulting mixture was applied to a mirror-finished stainless steel plate with a thickness of KSGμ using a coating rod bar and dried. Dip in a citric acid aqueous solution adjusted to pH 3K for 2 minutes, then wash with water and dry to create an opaque porous film sheet on a stainless steel plate. 90 Peel this film sheet from the stainless steel plate 3All
1. 50 parts by weight of synthetic zeolite (U, C, C, manufactured by Moleckier Coup 3A), 10 parts by weight of diacetylacetate, 130 parts by weight of acetone, and 20 parts by weight of ethyl acetate were mixed and crushed in a ball mill for 3 days. The resulting mixture was cast into a film with a thickness of about 30# by a casting method. This film was immersed in an aqueous acetic acid solution of pH 4 for 5 minutes, washed with water, and dried to produce an opaque film sheet.

This film notebook was pressed and laminated on one side of base paper (basis weight, 60 g/vt) coated with an aqueous solution of polyvinyl alcohol to obtain recording paper.

Sample D casei/10 parts by weight of an aqueous solution.

13X type zeolite) (U, C, C', Molekki 2lar Sheep 13X) powder was mixed with 1 part by weight of colloidal silica (20 weight - aqueous solution) as a water resistance agent, and heated in a ball mill for 3 days. The mixture was crushed and warmed. The obtained mixture was applied to a thickness of 40μ on a 100μ thick acrylic resin film using a coating rod bar and dried. After this film was immersed in a citric acid aqueous solution whose pH was adjusted for 2 minutes. , washed with water and dried to obtain an opaque porous film sheet.

Sample E 15 weight aqueous solution of gum arabic 1 [100 parts by weight and 1
Mix 30 parts by weight of 3X type zeolite (U, C, C', manufactured by Moleckier Sheep 13X) powder and 2 parts by weight of colloidal crystallization (20 weight - aqueous solution) as a water resistant agent, and mix it into a ball tube. The resulting mixed solution was coated with a coating rod parser to a thickness of 30 Jl on a stainless steel plate with an fIIA surface and dried. After dipping in an acid aqueous solution for 2 minutes, it was washed with water and dried to create an opaque porous film sheet on a stainless steel plate.

This film sheet was peeled from the stainless steel plate, laminated on one side of base paper (basis weight, 60#/11I), and then pasted (by heat press) to obtain recording paper. On the other hand, we performed intjet recording using the following four colors of ink, and examined the recording paper characteristics for the items listed in the table below. As stated in IK) and 9.

Yellow ink (composition) Ceramic, table below - IK indicates 9 dots) Measuring machine is Sakura Microdensitometer PM-S (manufactured by Konishiroku Photo Industry Co., Ltd.)
using a slit width of 30js*height 30μ, motorized speed in the X-axis direction of 10μ/Kan C, and chart feed speed I.
The sample feed rate ratio to M/sec chart is 1
These are the results obtained by measuring at 00x magnification. The dot diameter was determined by measuring the diameter of the printed dot using a cylindrical probe.

Also, during fixing, a rubber roller is placed a certain distance away from the VH & inkjet head, and the paper feeding mode is varied so that the time taken for the ink dot to contact the rubber roller can be changed. (2), the time from the time an ink dot is generated until the ink is no longer attached to the roller is measured.

In addition, the ink ejection port II (orifice length) of the inkjet distribution device used here is 50 degrees. After melting (melting) the resin layer of each sample while pressing with a commercially available iron having a surface ii* of 150°C, the resin layer was made transparent and each dot was measured in the same manner as before. The results and image quality evaluation are shown in Table 2 below.

In addition, each of the samples after the above heat treatment was immersed in water, but none of the ink came out at all and the water resistance was good.Table 2 Example 2 Samples C, D of Example 1, For I, respectively, fruit 1111
1tExample I Full-color inkjet recording was carried out using the four colors of ink shown in K, cyan, agenta, yellow, and puhook. It is also possible to reproduce full-color photographs with clear colors and good single-color reproducibility.

[Brief explanation of drawings]

Figures 1 to 3 are schematic diagrams of the configuration of recording paper used in the present invention. In the figure, 1 is a porous resin layer, 2 is a resin layer, and 3 is a substrate.

Claims (1)

[Claims] An inkjet recording method characterized in that after performing inkjet recording on a recording material having a porous resin layer as an ink receiving part, at least the surface of the resin layer becomes transparent when melted. .