JPS62227688A - Material to be recorded - Google Patents

Abstract

PURPOSE:To form a sharp image of high density and good color properties, by a method wherein a paper is made with use of a twin wire type paper machine. CONSTITUTION:In a Fourdrinier paper machine, in paper-making, dehydration is carried out from only one side of a paper layer and a yield of a material for a paper is high. As a result, the component of the paper fails to be fractionated, which makes the voids in the paper small in number and ununiform, therefore an ink absorption and a dot shape become unsatisfactory. On the other hand, with use of a twin wire type paper machine in paper-making, dehydration is carried out from both sides of a paper layer and a yield of a material for a paper is relatively low. As a result, a paper is made of an uniform fiber material, which makes the voids in the paper uniform and large in number, therefore an ink absorption and a dot shape etc. are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording material, and more particularly to a recording material for inkjet recording for recording with aqueous ink.

(Prior Art) Inkjet recording methods include various ink (recording liquid) ejection methods, such as an electrostatic suction method, a method that applies mechanical vibration or displacement to the ink using a piezoelectric element, and a method that heats the ink to foam it. Recording is performed by using a method that uses the pressure to generate and fly ink droplets, and some or all of them adhere to a recording material such as paper, but it generates little noise and It is attracting attention as a recording method that allows high-speed printing and multicolor printing.

Conventionally, the recording materials used in this inkjet recording method include commercially available heavy to medium-quality paper, generally called plain paper, which is made using a Fourdrinier paper machine, and recording materials called inkjet recording paper. It has been used.

Although commercially available medium-quality papers have excellent writing properties and printability, they have the following drawbacks when subjected to inkjet recording.

(1) During or after inkjet recording, if a part of the recording device or your finger touches the recording section, the ink will not be received quickly and the ink that has not been accepted will rub off.
Staining occurs, significantly reducing image quality. Additionally, records may become illegible.

(2) After the ink adheres to the recording material, feathering occurs from the dots, resulting in dots with extremely low roundness. For this reason, the dot shape is poor and a clear image cannot be obtained.

On the other hand, as the performance of inkjet recording devices improves and spreads, various recording materials have been devised as recording materials for inkjet recording in order to obtain high-resolution, high-quality recorded images (for example, JP-A-59 -35977, JP 58-132586, JP 52-74340
(see publication).

However, JP-A-59-35977 and JP-A-58
The recording materials described in Japanese Patent No. 132586 and the like are coated papers for inkjet recording that have high ink absorbency and excellent color development, but these recording materials have the following drawbacks.

(3) When writing on a recording material with a writing instrument such as a pencil or a fountain pen, the ink receiving layer is scratched and the writing cannot be done properly.

(4) When inkjet recording is performed on the recording material.

Mechanical friction between the recording material and the paper feeding part of the recording device causes the coating layer to peel off, which is called powder falling off.
Contaminate recording equipment. In particular, if the fallen ink receiving layer adheres to the head of an inkjet recording device, it may cause clogging of the nozzles of the head.

Furthermore, the inkjet recording paper described in Japanese Patent Application Laid-open No. 52-74340 and the like has the following drawbacks when inkjet recording is performed.

(5) Low dot density.

(6) The dot periphery tends to be blurred, making it impossible to obtain a clear image.

(7) A phenomenon in which ink oozes out to the back side of the recording surface, so-called strike-through, occurs.

Conventional recording materials have one or more of the above-mentioned drawbacks, and at present no recording material that solves all of these drawbacks has been obtained.

Therefore, it is an object of the present invention to provide a high-performance inkjet that solves the above-mentioned drawbacks, has rapid ink absorption, has excellent dot shape, and forms clear images with especially good color properties and high image density. The object of the present invention is to provide a recording material for recording.

(Disclosure of the Invention) That is, one aspect of the present invention is a recording material characterized in that it is made by a twin wire type paper machine.

Next, the present invention will be explained in more detail.1 As a result of intensive research to obtain a recording material for inkjet recording that uses water-based ink, the present inventor has found that pulp It has been found that for recording materials such as paper mainly composed of, the paper-making conditions at the time of paper making are important for various performances of the recording material.

That is, in the case of conventional inkjet paper 5, such as high-quality paper or medium-quality paper, paper is mainly made using a fourdrinier paper machine, and paper made by this method has poor ink absorption properties and also has poor ink absorption properties that are formed on the surface. - The shape of the dots was unstable, and the color, sharpness, and resolution of the formed images were poor. For this reason, various efforts have been made to improve the inkjet recording suitability of these papers, and as a result, the cost of inkjet paper has increased, and the inkjet system has not been sufficiently compatible with plain paper.

In view of these points, the inventor of the present invention made paper by changing various paper-making conditions during paper-making, and as a result of detailed research on the inkjet recording suitability of the resulting paper, he developed a paper machine using a Tsujin wire type paper machine. When paper was made using this method, the suitability for inkjet recording was significantly improved, and as a recording material for the inkjet method, it had excellent ink absorption, did not cause ink bleeding or feathering, gave an excellent dot shape, and in particular had excellent color performance. It was found that recorded images with good density and high resolution were obtained.

The effects of the present invention as described above are that when paper is made using a twin wire type paper machine, water is removed from both sides of the paper waste during paper making, and the paper stock yield is relatively low, resulting in paper being made from a uniform fiber material. As a result, the number of voids in the paper formed is uniform and large, which is thought to result in good ink absorbency, dot shape, etc. On the other hand, in the case of paper making using a conventional Fourdrinier paper machine, dewatering is performed only from one side of the paper layer, and the paper stock yield is high, resulting in the paper's constituent materials not being separated. It is thought that the ink absorbency and dot shape are poor because the voids in the paper are small and non-uniform.

1. The twin wire type paper machine referred to in the present invention is a type of paper machine that forms paper waste between two wires, and corresponds to this type of paper machine, such as a Verpeformer, Birchformer, Pubrifformer, and Twin Performer. .

The recording material of the present invention has the above characteristics.

Everything other than the paper machine used is obtained in accordance with conventionally known papermaking methods. For example, the main ingredients are hardwood bleached kraft pulp and softwood bleached kraft pulp, which are widely used in conventional paper manufacturing. The main raw material is pulp, and depending on the purpose, synthetic pulp, synthetic fibers, etc.
Glass fibers, etc. are used in combination, and then fillers as fillers, sizing agents, various binders, dispersants, waterproofing agents,
It can be obtained by blending necessary additives such as retention improvers and fluorescent dyes and making paper.

Furthermore, the recording material of the present invention may have a coating layer containing a pigment or the like formed on its surface.

Pigments used to form such a coating layer include, for example, finely divided silica, clay, talc, kaolin, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, and silicic acid. Particularly preferred pigments include aluminum and lithopone.

The silica has an average particle diameter of 1#Lm to 20ILm.

Formation of a coating layer consisting of the above-mentioned pigment involves dispersing the pigment in a medium such as water at a concentration of, for example, 5 to 50% by weight, adding a suitable binder, and preparing a coating solution. The coating solution is applied to the above substrate by a known method such as the roll-to-coat method, /<-coater method, blade coater method, air knife coater method, size press method, gate roll method, etc. . The thickness of the coating layer is usually 1 to 15
4 m (dry coating amount), preferably about 2 to 12 pm.

The binders used in the above are 1, for example, water-soluble polymers such as starch, gelatin, casein, gum arabic, sodium alginate, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, and sodium polyacrylate, and 5 synthetic rubber latex. Any conventionally known binder such as synthetic resin latex, water-insoluble polymers such as polyvinyl butyral and polyvinyl chloride can be used. These polymers are pigment 10
Preferably, it is used in a proportion of about 10 to 200 parts by weight per 0 parts by weight.

The recording material of the present invention as described above can be used for fountain pens, felt-tip pens,
It is suitable not only for general writing instruments such as ballpoint pens that use water-based ink, but also as a recording material for inkjet recording that uses water-based ink, and has the following effects.

(1) Because the water-based ink is highly absorbent, the ink will be in the same state as when it dries immediately after being applied, and even if parts of the recording device or fingers are attached, they may be contaminated or the recorded image may be smeared. There is no.

(2) When used for inkjet recording, the above (
In addition to the effect of 1), the ink dots are nearly perfect circles and have high density, and the dots do not bleed excessively or feather from the dots, making it possible to form clear and high-resolution images.

(3) From the above points, the recording material of the present invention has very good monochromaticity and is suitable for forming color images.

Therefore, the recording material of the present invention is excellent not only as a general recording paper but also particularly as a recording material for inkjet recording. The recording material of the present invention is also useful for thermal transfer paper, wire dot printer paper, electrostatic recording paper, etc., and has excellent versatility.

Next, the present invention will be explained in more detail with reference to Examples, Comparative Examples, and Usage Examples. In addition, parts and percentages in the text are based on weight unless otherwise specified.

Example 1 A raw material pulp was prepared by mixing 90 parts of bleached hardwood kraft pulp (LBKP) and 10 parts of bleached softwood kraft pulp (NBKP). After adding 15 parts of clay, 0.02 part of rosin sizing agent, and 0.1 part of sulfate to this raw material pulp.

A high-quality paper having a basis weight of 73 g/rd was made using a Velpeformer, and then surface size treatment was performed using oxidized starch to obtain a recording material of the present invention.

Example 2 A raw material pulp was prepared by mixing 50 parts of LBKP and 50 parts of NBKP. Calcium carbonate 2
0 part, wet paper strength agent (polyamide/polyamine-epichlorohydrin resin) 0.01 part and cationic starch 0
．． After adding 5 parts, the basis weight is 64g/
A recording material of the present invention was obtained by making a high quality paper and then subjecting it to surface size treatment with a mixture of polyvinyl alcohol and carboxymethyl alcohol.

Example 3 A mixture of silica and polyvinyl alcohol (weight ratio 3:1) was coated on the surface of the recording material obtained in Example 2 at a solid content of 4 g/g, and the recording material of the present invention was prepared. I got it.

Comparative Examples 1 to 3 Recording materials of Comparative Examples 1 to 3 were obtained in the same manner as in Examples 1 to 3, except that the paper was made using a Fourdrinier paper machine in each of Examples 1 to 3.

Example of Use For each of the recording materials of Examples 1 to 3 and Comparative Examples 1 to 3, an on-demand inkjet recording head (discharge Inkjet 2 printing was carried out using a recording device having an orifice diameter of 60 gm, a piezo vibrator drive voltage of 7°V1 frequency a2, 6 KHz).

Wave pressure zl (composition) C0! , Direct Yellow 86 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
68 parts Llzlc composition) C, 1, Acid Red 35 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
68 parts 1 engineering zl (composition) C0! , Direct Blue 86 2 parts diethylene glycol 20 parts polyethylene glycol #200'I 0 parts water
68 parts 1 EL (composition) C, 1, acid black 26 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
Evaluation results of the recording materials of the 68-part Example and Comparative Example are shown in Table 1.

Each evaluation item in Table 1 was measured according to the following method.

(1) Ink fixation time was measured by measuring the time required for the ink to dry and stop adhering to the finger when touching the recorded image after recording.

(2) The dot density was calculated using Sakura Microdensidometer PD by applying JISK7505 to the printed microdots.
The black dots were measured using M-5 (manufactured by Konishiroku Photo Industry Co., Ltd.).

(3) The dot shape coefficient is: - Measure the dot area using an image analysis device, assume a circle with the same area as the dot, calculate its circumference L1, and calculate the length of the dot's circumference. It was measured and calculated using the following formula.

Dot shape factor = L+ /Lx x 100 (%) (
4) For the panel test, a sample of 1010 x 20 was created and 40 people (24 men, 16 women) were asked, "Which one has the best sharpness and contrast?" One point was given to the worst answer, and the total score was shown for a comprehensive evaluation.

Claims (2)

[Claims] (1) A recording material characterized by being made using a twin wire type paper machine. (2) Claim No. (2) for inkjet system
The recording material described in item 1).