JPS61179781A - Ink jet recording method - Google Patents

Abstract

PURPOSE:To ensure rapid absorption of a recording liquid and prevent an ink adhered subsequently from distorting or flowing out dots previously adhered in the case where ink dots are overlapped on each other, by a construction wherein an ink-receiving coated film incorporating a surfactant or an inorganic pigment and comprising cracks is provided on a liquid-absorbing base for a recording material. CONSTITUTION:The liquid-absorbing base 1 consists of a porous material such as a paper and a cloth. The coated layer 2 is formed of a resin coating material capable of receiving an ink and forming a film. A white inorganic pigment which is porous and has ionic property at the surfaces of particles is used as a component for enhancing the adsorption and trapping ratio of a dye in the coated layer 2. A coating material is applied to the base 1, and is dried as rapidly as possible. In the coated layer 2 thus obtained, coatings 3 are closely arranged in two dimensions, with irregularly shaped cracks 4 therebetween. When an ink is adhered to the coated layer 2, the dye in the ink is trapped into the region of the coatings 3, and a major portion of a solvent in the ink penetrates through the cracks 4 and is rapidly absorbed into the base 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording method, which is one of the non-impact recording methods.

[Conventional technology]

BACKGROUND ART Conventionally, recording using a recording liquid or ink has been widely performed using a writing instrument such as a pen, a fountain pen, or a felt pen. Also, recently, so-called inkjet recording methods have appeared, and recording liquids are being used even in busy times.

Incidentally, this inkjet recording method uses various ink ejection methods (for example, an electrostatic suction method, a method that applies mechanical vibration or displacement to the ink using a piezoelectric element, a method that uses a piezoelectric element to apply mechanical vibration or displacement to the ink, and a method that heats and foams the ink and uses the pressure A method using ink droplets is known.
A part or all of it is attached to a recording material such as paper to perform recording.

In this way, when recording using liquid ink, it is generally necessary to prevent the ink from bleeding on the surface of the recording paper and burying the printed characters, and it is also necessary to prevent the ink from bleeding on the surface of the recording paper, and also to prevent the ink from bleeding as quickly as possible after recording. to prevent the paper from drying out and accidentally contaminating the paper surface, and
It is desirable that the pigment in the ink fixed on the paper does not fade.

In particular, in the inkjet recording method, (1) the absorption of the recording liquid (ink) into the recording paper is fast; and (2) in particular, when performing multicolor or full color recording, the ink dots are Even if there is overlap, the ink droplets deposited later will not disturb or spill out the dots deposited earlier, and the ink droplets will spread on the recording paper surface and the diameter of the ink dots will be smaller than the required diameter on the recording paper. ■ The shape of the ink dot must be close to a perfect circle, and the area around it must be smooth; ■ The density of the ink dot must be high and the area around the dot must not be blurred. ■ The color of the recording paper must be white, and the ink dot must be smooth. ■ The color of the ink does not change depending on the type of recording paper; ■ There is little scattering of ink drops around the ink dots; ■ There are no dimensional changes in the recording paper (e.g. wrinkles, spread) before and after recording. It is necessary to satisfy various requirements, such as: However, in the past, it has been understood that satisfying these demands largely depends on the characteristics of the recording paper used, but in reality, plain paper and processed paper Recording paper that meets various demands is still not available. For example, the processed paper for inkjet recording described in JP-A-52-74340 absorbs ink quickly, but the diameter of the ink dots is large, making it easy to blur, and the periphery of the dots tends to blur. This method has a practical disadvantage in that the dimensional change of the paper after recording is large.

[Problem that the invention seeks to solve]

The main object of the present invention is to satisfy the problems that the prior art could not solve in the technical field mentioned above. and)
In particular, the present invention aims to satisfy almost all of the above-mentioned requirements in recording using liquid ink using an inkjet recording method.

[Means for solving problems]

The present invention, which achieves the above object, is an inkjet recording method for recording on a recording material using ink droplets, wherein the recording material contains at least a surfactant or an inorganic pigment in a liquid-absorbing base and is free from cracks. It is characterized by having an internal ink-receptive coating.

[For production]

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

First, the structure of the recording material used in the present invention will be outlined using the schematic diagram of FIG.

In the figure, the substrate is 1 digit liquid-absorbing, such as paper,
Consists of porous materials such as porous plastic films and cloth. 2 is a covering layer which receives ink. This coating layer 2 is basically composed of a film-forming resin paint, but various surfactants and porous inorganic particles may be further mixed into the paint. Such surfactants and porous inorganic particles are components that can enhance adsorption and capture of pigments (for example, dyes) in the ink in the coating layer 2, and in the present invention, It is desirable to use it actively. In the present invention, a white inorganic pigment that is porous and has ionicity on the particle surface can be particularly effectively used as the component.

Specifically, natural zeolite, synthetic zeolite (for example, Molecular Sheep [manufactured by Union Carbide]),
Calcium carbonate, diatomaceous earth, fine powder silica (average particle size, 1 μ or less), silica (average particle size, 20 μ or less), synthetic mica [general formula: M-Mg2.5 (S14.01o).
F: However, in the formula, M is a hydrogen atom or a metal atom. ]
, etc. can be used.

In the present invention, a coating paint is prepared by mixing and dispersing these particles (generally particles from several hundred millimeters to several microns) alone or in combination in a resin paint. Incidentally, as the resin in this paint, either water-soluble or organic solvent-soluble resin can be used. For example, water-soluble resins include polyvinyl alcohol, starch, casein, gum arabic, 8BB, gelatin, polyacrylamide, polyvinylpyrrolidone, carboxymethylcellulose, sodium polyacrylate, sodium alginate,
Examples of organic solvent-soluble resins include polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide resin, phenol resin, polyurethane resin, alumina resin, etc. . The mixing ratio of the inorganic pigment particles and the resin component in such a paint is generally 5 to 20 parts by weight of the resin component to 100 parts by weight of the inorganic pigment.

To form the coating layer 2, generally about 1 g/- to 10 g/- is coated on the substrate 1 by a known method (e.g., roll coating method, Rotbur coat ink method, spray coating method). Apply the amount of paint.

Practically speaking, it is preferable to apply the coating at a rate of about 2 g/i to 5 g/n/.

After the various coating layers have been applied, the coating layers are dried as soon as possible. The coating layer 2 thus obtained has sI/c1 amorphous cracks 4 (...this crack Most of the coatings 3 reach the surface of the base 1), and the coatings 3 are two-dimensionally arranged in close contact with each other. The size of one film 3 is 4
Although not limited to 9, approximately 10μm×10μ
m to several hundred μm x several hundred μm is common, and
The width of the crack 40 is also not particularly limited, but usually
It is said to be about several pm.

Incidentally, the individual size and shape of the coating 3, the width of the cracks 4, etc. can be controlled by adjusting or controlling the composition or film forming conditions of the coating material, especially the drying conditions after coating. It can be changed arbitrarily within the range.

When the ink adheres to the coating layer 2 explained above,
Pigments (for example, dyes) in the ink are selectively adsorbed and captured in areas of the coating 3, while most of the solvent in the ink passes through the cracks 4 and quickly enters the substrate 1. It is absorbed by crabs. In this way, in the present invention, the coloring matter in the ink is captured in the outermost surface area (edge, coating layer) of the recording paper, resulting in extremely good color development.

Furthermore, since the solvent in the ink quickly migrates to the underlying substrate through the cracks, an apparent dry state can be quickly achieved on the surface of the recording paper.

Furthermore, the coating 3 is particularly effective in preventing ink dots from becoming unnecessarily large, ensuring high dot density, and preventing the periphery of the dots from becoming blurred.
This is because the pigment in the ink is concentratedly adsorbed in the area. The adsorption ability is determined mainly by the surface physical properties and chemical properties (for example, ionicity) of the coating 3 itself, surfactant, and pigment particles. Therefore, if the area occupied by the coating film 3 in the coating layer 2 is extremely small, there is a drawback that the dye trapping capacity is reduced and the color development and density of the dots are reduced. If it is large, the amount of ink transferred to the substrate increases, resulting in so-called ink bleed-through, and there are disadvantages such as deterioration of dot shape. Therefore, these aspects are preferably avoided.

〔Example〕

Here, more detailed examples will be explained to illustrate the effects of the present invention.

Example 1 Silica (100 parts by weight) and polyvinyl alcohol (20 parts by weight)
Parts by weight) were dispersed and dissolved in water, and then ground and mixed in a ball mill for 12 hours to obtain a slurry.

The slurry was applied to one side of five sheets of base paper (basis weight, 60 g/m') so that the dry solid content was about 4 g/m'.

Next, these were dried under the following conditions and recorded paper sample I
～■ was created.

Bamboo drying conditions Sample processing: Natural drying sample L: Sample I for 2 hours in an oven (60°C)
... Sample V for 30 minutes with hot air at 90°C - 1 minute with hot air at 110°C Sample V ... 2 seconds with hot air at 180°C, and then take an electron micrograph (X200) of the surface condition of each sample. , and the like are faithfully reproduced and shown in FIGS. 2 to 6.

The results of a comparative study of the characteristics in inkjet recording of each of the samples thus obtained are summarized in Table 1 below. In Table 1 below, the dot density was measured using a Sakura microdensitometer PDM-5 (manufactured by Konishiroku Photo Industries Co., Ltd.) with a slit width of 30μ in width and 30μ in height, and a slit width in the X-axis direction. Electric speed 10μ/sec.

Chart feeding speed 1 m/Sec The sample feeding speed ratio to the chart is the result of measurement at 17100 times. The dot diameter was determined by measuring the diameter of the printed dot using a stereomicroscope.

The fixing time can also be determined by placing a rubber roller a certain distance away from the inkjet head used, and changing the paper feed speed so that the time it takes for the ink dots to contact the rubber roller can be changed using an optical device. The time taken from the time an ink dot was generated until the ink stopped adhering to the roller was measured.

The ink jet recording apparatus used here had an ink ejection opening diameter (orifice diameter) of 50 μm, and the ink used had the following composition.

Ink physical properties: Viscosity: 3.8 cps (measured with an Efi rotational viscometer manufactured by Tokyo Keiki) Surface tension: 52.4 d'/ne/cm (measured with a suspended plate surface tension meter manufactured by Kyowa Kagaku) Table 1 (Note 1) ): @I - WB in the tube place - Nail-like front torrent L°
Example 2 Diatomycin ± (too parts by weight) and sodium alginate (15 parts by weight)
Parts by weight) were dispersed and dissolved in water, and ground and mixed in a ball mill for 15 hours to prepare a slurry. This slurry was applied to the surface of a base paper with a basis weight of 65 g/- so that the dry solid content was 4 g/-, and dried with hot air at 180° C. for several seconds to prepare a recording paper. When an electron micrograph was taken of the surface of this coating layer, a photograph equivalent to that shown in FIG. 6 was obtained.

Further, when inkjet recording was performed on this recording paper in the same manner as in Example 1, the results were similar to those of Sample V in Example 1.

Example 3.4 Inkjet recording was performed on the same sample as Sample V obtained in Example 1 using the inks shown in Table 2 below in the same manner as in Example 1, and the results were as shown in Table 2 below. That's right.

Table 2 Note that the numbers in parentheses in the ink composition column indicate parts by weight, and all other numbers are based on Example 1.

Example S Full-color recording was performed using the same sample as Sample V of Example 1 using each ink of white, cyan, magenta, yellow, and black, and the fixing time, dot density, and dot diameter were all the same as in Example 1. It was possible to obtain full-color photographs with extremely clear colors and good color reproducibility.

As mentioned above, in the present invention, the recording liquid (ink) adhering to the recording material is quickly absorbed into the inside of the recording material, and even if recording liquids of different colors adhere to the same spot repeatedly within a short time, However, it is possible to suppress the spread of ink dots, which may cause the phenomenon of recording liquid flowing out or seeping, to a degree that does not impair the sharpness of the image quality. Further, according to the present invention, since the color development of the ink droplets is good, it is possible to provide a recording method suitable for multicolor ink recording.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the structure of the recording material used in the present invention, and FIGS. 2 to 6 are all copies of electron micrographs of the surface of the recording paper according to the present invention. In the figure, l is the base, 2 is the coating layer, 3 is the coating, and 4 is the crack. Procedural amendment blind motion) February 17, 1985 Mr. Michibu Uga, Commissioner of the Patent Office' 1, ゎ1. . Okay, 1985 Patent Application No. 176082 2, Name of the invention Inkjet recording method 3, Relationship with the case of the person making the amendment Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (100)
) Canon Co., Ltd. Representative Nozo Kaku
Part 4, Agent residence: 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, Date of amendment order (shipment date) January 28, 1986 6, Drawings subject to amendment 7, Contents of amendment, Figures 2 to 2 The drawing that clearly depicts Figure 6 shall be corrected as shown in the attached sheet.

Claims (1)

[Claims] In an inkjet recording method in which recording is performed on a recording material using ink droplets, the recording material is provided with an ink-receptive coating film containing at least a surfactant or an inorganic pigment and containing cracks on a liquid-absorbing substrate. An inkjet recording method characterized by: