JPS5872495A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To obtain clear-cut recorded pictures by providing the binder coat layer of a water-soluble high-molecular compound containing a silica pigment on a base paper. CONSTITUTION:A binder coat layer (15g/m<2> or more) of a water-soluble high- molecular compound containing a silica pigment of an average grain size of 0.05mu or less is provided on one side of a base paper. The silica pigment used is a synthetic precipitated silica pigment based on silicone dioxide, having an average grain size of 0.05mu or less, e.g., synthetic amorphous silica and synthetic sodium aluminosilicate, and the synthetic amorphous silica, however, is excellent particularly. The water-soluble high-molecular binder used includes oxidized starch, modified starch, polyvinyl alcohol, sodium alginate and carboxymethyl cellulose. The preferred amount of the pigment in a paint is 75-95:25-5 in silica pigment (0.05mu in average grain size):binder proportion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording paper suitable for an inkjet recording method, in which ink droplets adhering to the paper surface are quickly absorbed into paper waste, and the ink dots spread out on the paper surface. The present invention relates to an inkjet recording paper that can provide clear records by making the size as small as possible.

The inkjet recording method has attracted attention in recent years because of its low noise, ease of colorization, and high-speed recording, and its application to facsimile machines, various printers, etc. is expanding.

Generally, plain paper can be used in the inkjet recording method, but in order to obtain good recording, the paper itself must meet the following conditions. That is, all has good ink absorbency, and ink droplets that adhere between the paper surfaces are quickly absorbed into the inside of the paper layer, resulting in an apparent rolling state.Secondly, the ink droplets attached to the paper surface are The goal is to suppress the spread.

The first condition is the most basic condition for inkjet recording paper.If the ink droplets that reach the 6 paper WK are not quickly absorbed into the paper layer and remain on the surface of the paper, it may cause stains.
In the case of multi-color recording on IF#, the ink of several colors will adhere to the same or close location on the paper surface in a very short time. increases compared to monochrome recording. Good absorbency is therefore particularly important in shortening drying time and preventing staining.

The second condition is an essential condition for obtaining clear recorded images. The spreading of ink dots in the plane direction also occurs in the form of penetration into paper waste. Therefore, by suppressing the blurring of ink dots, not only the resolution of the recorded image can be improved, but also the recording density can be increased by increasing the amount of ink per unit area of the paper surface. A/Among the current jet recording methods, the on-demand method and the electric field control method are particularly effective. The diameter of the ink dots is required to be as small as possible, and the shape of the ink dots is required to be close to a perfect circle.

In general, the above-mentioned first and second conditions are contradictory because the ink dot spreading speed is generally high in paper having high ink absorbency. Therefore, it is desired to develop an inkjet recording paper that satisfies these two conditions at the same time.

JP-A-55-51585K>In et, particle size α1~1
In-jet recording paper has been proposed which is provided with a coating layer containing 0μ non-colloidal silica powder and a polymeric binder. However, the nine inkjet recording paper using this non-colloidal silica powder with a particle size of 11 to 10μ can produce recorded matter with a smaller dot diameter than other general pigments such as calcium carbonate, clay, and Merck. However, at a coating amount of 7F//11 degrees, the size of the dot diameter deviates from the equilibrium value, and even if the coating amount is increased beyond that, the dot diameter will not become smaller.

In the present invention, a paint containing a silica pigment with an average particle size of α05μ or less and a water-soluble polymer binder is coated on a base paper in an amount of 1 coated on one side.
It is characterized by applying 5 f/- or more.

The dot diameter of this paint is relatively large when the coating amount is about 4 to 71/l, but the dot diameter decreases significantly as the coating amount increases, and the dot diameter is 20 f/lt? The feature is that the size of the dot F diameter does not reach an equilibrium value until the amount of cloth reaches about m.

The present invention will be explained in detail below.

In general, bleached chemical pulp such as NBKP%NBSP, LBKP, LB8P, etc., which has been beaten to a desired 7-ness, is added with GP, 'rMP, etc. as necessary to adjust the Steckigt size degree of Hogashi paper. Mechanical pulp such as, cow mechanical pulp such as CCP, starch, polyacrylic acid resin and derivatives thereof.

Melan formaldehyde resin, urea formaldehyde resin, paper strength enhancer such as date resin, reinforced loaf 1 petroleum resin system 1
Synthetic polymers or luketene dimer in alcohol, and other fixing agents; talc, clay, heavy or light calcium carbonate;

Inorganic fillers such as aluminum hydroxide, natural monochloride, titanium oxide, or organic fillers such as powdered urea formaldehyde resin, dyes, and retention aids.

In addition, products that have been added with chemicals commonly used in papermaking to make IC gauze, or products that have been externally added with oxidized starch, other paper strength enhancers, and sizing agents as necessary. %, but is not limited to the composition of the base paper itself.

The silica-based pigment used in the present invention refers to a synthetic precipitated silica-based pigment containing silicon dioxide as a main component and having an average particle diameter of 1 L05J11 or less, and can be exemplified by synthetic amorphous silica and synthetic sodium arunnosilicate. However, synthetic amorphous silica is particularly excellent. In addition, pigments other than silica pigments with an average particle diameter of α05μ or less include clay, talc, calcium carbonate, and carbonic acid! Gnesium, palladium sulfate, titanium white, etc. may be used in combination.

On the other hand, water-soluble polymer binders include: oxidized starch, modified starch, polyvinyl alcohol, guar gum, gums such as 4-cast bean gum, sodium ruginate, carboxymethyl cellulose, diethyl cellulose in hydrochloride, and other water-soluble The isomorphic common ratio of the binder and the cellulose derivative, casein, gelatin, and polyvinyl aliphatic pigment is 75 to 9.
A paint containing a 5:2 polymer as a binder is applied onto the base paper using a conventional coating machine such as a blade, air knife, or seal coater, or by a machine such as a Nize press. That is, the solid content is applied to the base paper at a rate of 15 f/- or more, preferably 20 f/- or more on one side.

It is possible to obtain inkjet recording paper with a small dot diameter, a nearly perfect circle shape, and high resolution.

The base paper used in the present invention is one with a low sizing degree, such as a Steckigt sizing degree of 0 to 1.5 seconds 760.
1/- paper is desirable; that is, a paint containing ultrafine silica-based pigments and a water-soluble polymer as a binder is applied to the round wire, because the binder is more easily absorbed into the paper layer with low-size paper. , an abundant amount of minute voids are formed in the coating layer due to the high raw material composition ratio.

As a result, it is presumed that the dye in the ink is more effectively adsorbed to the coating layer on low-size paper.

The present invention will be explained below according to examples. In addition, at the ninth stage of the quality test of the recording paper according to the present invention, a test pattern was recorded using a Kotori Roku inkjet printer R-180 (letter near x 9 dot hetrix).
This printed matter was evaluated for the following three IK items.

The diameter of the dot on the paper: Multiply the particle analyzer (Ruzetx 450.8 pieces, made by Gulator) by K, and write 10 letters from A to J over 5 lines for a total of 5
92 Dot shape: Magnify and observe the dots on each brass object with a magnifying glass to determine the degree of 1 yen, and measure the dot diameter from the area of 1 dot. A is the best.

The evaluation was conducted on the 3R floors of B and C. In addition, when distinguishing between 0 and 0, those with large feathering were evaluated as C.

5 Drying time 2 Ink manufactured by Nippon Toyo Co., Ltd. (BX-204)
) α o o s cc was dropped onto the paper from a height of 1 cIR using a microphone a tarringe in an atmosphere of 20 C and 65 cm relative humidity, and the time until it was completely absorbed was measured.

[-Preparation of paper]

It was prepared by the following method. ~7 Leeness 550d.

LBKP80 Weight S-ness 450-NB
30 parts by weight of clay was added to a raw material pulp consisting of 20 parts by weight of KP, and after paper was made using a Fourdrinier machine in a conventional manner, oxidized starch (Tamago Ace B, manufactured by Oji Cornstarch) and styrene were added.
Size pressing was performed using a mixed solution of 5 parts by weight of 9a and 5 parts by weight of t with an acrylic copolymer (Pearl Gum C8, manufactured by Kokuko Kagaku). This paper has a weight of 60 f/d (of which the size component is about 597 d), and a Steckicht sizing degree of 6.
Indicates seconds.

15-Water soluble T 10 parts by weight (solid content) and 20 parts by weight (solid content) K, average particle size (LO 3μ) synthetic amorphous silica of Electrification Handmade) with Tubseal 1150J.

Two types of paints were prepared by mixing 90 parts by weight (solid content) and 80 parts by weight (solid content) of slurries manufactured by Nippon Silikani Gyogyo Co., Ltd., respectively. In the same way, ultrafine silica was added with an average particle size of 5 μm.
Two types of paints were prepared with different amounts of silica and fine powder silica (Tart 7DR-1, Mizusawa Kagakuten). The coating amounts of these four types of paint on the base paper were approximately 5.10.15. and 20 f/wl
Recording sheets (1) to (16) were obtained by applying the coating so as to give the following properties.

The results of the sickle test for these recording papers are shown in Table 1 and FIG. 1, as shown in Table 1 and FIG. 1, in the case of recording papers containing ultrafine silica particles with an average particle diameter of a03μ as a pigment, the dot diameter of the recorded material becomes smaller as the coating amount increases. 4I, recording papers (3), (4), (7), and (8) with a coating amount of ~15 f/- or more have extremely small dot diameters, good dot shapes, and short drying times and good recording. It shows the characteristics. On the other hand, in the comparative example of recording paper using fine powder silica as a pigment, the relationship between the coating amount and the dot diameter of the recorded material showed a tendency to vary depending on the blending ratio of pigment and binder. As is clear from FIG. 81, which is a graph of the relationship between the dot diameter and the dot diameter, the slope of the curve in the comparative example is small, and the dot diameter reaches equilibrium at a coating amount of about 10 to 15 f/d.

[Example 2] Hydroxyethylcellulose 5% water 1111! 10 parts by weight (solid content) and 20 parts by weight (solid content).

Synthetic sodium arunnosilicate (Zeolex 17S.

A coating material was prepared by mixing 90 parts by weight (solid content) and 80 parts by weight (solid content) of slurry of J. 24)
I got it.

The recording test results for these recording papers are shown in Table 2, and as the coating amount increases, the dot diameter of the recorded material becomes smaller.
5) and (24) are particularly good. The shape of the dots was also close to a perfect circle, and the drying time was short, and it was observed that the dot diameter tended to become smaller as the blending ratio of pigment was increased.

[Example 3] To 15 parts (solid content) of a 15-part aqueous solution of partially saponified polyvinyl alcohol (PC-100, manufactured by Denka Handicraft), synthetic sodium aluminosilicate (Zeolex 178% J, M) with an average particle size of CLO 25μ was added. , manufactured by Hieper) Nossurry 8
A paint was prepared by mixing 5 parts by weight (solid content). Similarly, synthetic sodium aluminosilicate was added to finely powdered silica (JILTON DR).
-1, Mizusawa Chemical), heavy calcium carbonate (FC-30
, manufactured by Kyuubi Calcium), light calcium carbonate (Akadama, Shiraishi Calcium 11), kaolin (UW-90, manufactured by Engelhard), talc (manufactured by Nippon Merck), and calcium silicate (Solex CM, Maruo Calcium 11). Then, paints were prepared.These seven types of paints were applied onto a base paper at a coating amount of about 20 t/d to obtain recording sheets (25) to (31).

The recording test results for these recording sheets are shown in Table 3.
It is clear that the recording paper (25) according to the present invention has a significantly smaller dot diameter, better dot shape, and shorter drying time than recording paper using other pigments.

[Brief explanation of drawings]

FIG. 1 is a graph '97 showing the relationship between coating amount and dot diameter for the test results of Example 1. Patent applicant Jujo Paper Co., Ltd.

Claims (2)

[Claims] (1) Contains a silica pigment with an average particle diameter of 05μ or less and uses a water-soluble polymer as a binder, and the coating amount on one side is 15f/-
An inkjet recording paper characterized by being provided with the above coating layer. (2) The ink jet recording paper according to claim 1, wherein the solid content ratio of the silica pigment to the water-soluble polymer binder is 75 to 95 to 25 to 5.