JPS6063191A - Recording material - Google Patents

Abstract

PURPOSE:To provide a recording material having a high ink-absorbing property and an appropriate degree of blurring and capable of providing a favorable ink dot shape and a high picture element density, wherein a surface layer in the thickness direction of a recording material consists of a mixture of a filler and a fibrous material. CONSTITUTION:A part of fibres 5 of a base 4 consisting of a fibrous material and a filler (e.g., silica having a particle diameter 0.05-50mum) 6 are mixedly provided at a surface layer part 3 in the thickness direction of the recording material, and a binder (e.g., starch) is mixed therein, if required, to obtain the objective recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording material (recording paper) used in an inkjet recording method, which has high ink (recording liquid) absorption, has an appropriate degree of bleeding, and has a good ink dot shape. The present invention relates to a recording material for inkjet recording, which provides a high pixel density.

The inkjet recording method uses an ink ejection method, such as an electrostatic attraction method using a high voltage application or a method that applies mechanical vibration or displacement to the ink using a piezoelectric element, to generate small droplets of ink, which are then flown onto paper, etc. This recording method generates little noise and allows high-speed printing and multicolor printing.

Inks for inkjet recording are mainly water-based in terms of safety and printability, and generally include a recording agent and a liquid medium.

As the recording material used in this inkjet recording method, conventional paper has generally been used. but,
2. Description of the Related Art 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.

This kind of recording material for inkjet recording has the following characteristics: 1) Ink absorption is as quick as possible, and 2) When ink dots overlap, ink that adheres later does not flow onto the previous dot. 3) The diameter of the ink dot should be the desired size and uniform; 4) The shape of the ink dot should be close to a perfect circle and the periphery should be smooth; 6) The whiteness should be high; 7) The ink It is necessary that the coloring component has excellent coloring properties and satisfies the following performance requirements.

On the other hand, when recording on a recording material using the inkjet recording method, generally the image to be recorded (original image) is evenly divided into fine parts, and each unit (pixel) of the finely divided image is The original image is reproduced on the recording material by a method of expressing it with one ink dot or a plurality of ink dots during recording. In such a recording method, in order to provide a sufficient recording density to a recorded image, it is necessary to obtain a sufficient pixel density (recording density for one pixel as a whole). To do this, for example, to explain the case where one pixel is expressed as one ink dot using the same amount of ink with the same recording agent concentration, the ink dots recorded in one pixel spread as uniformly as possible over the entire pixel. It is preferable to record it as follows. Because, in general, 1
When an ink dot with a small diameter is recorded in a pixel, the recording density of the ink dot itself becomes high, but the pixel density becomes low. On the other hand, as the diameter of the ink dot increases, the recording density of the ink dot itself decreases, but conversely, the pixel density increases. Then, the ink dots are uniformly distributed over the entire pixel.
This is because the pixel density reaches its maximum when it spreads to . This is because pixel density is mainly defined by the relative relationship between a recorded portion and a non-recorded portion within one pixel.

Further, if recording is performed using a recording material with a higher degree of bleeding, a larger pixel area can be used for recording, and the recording speed can be increased.

Therefore, in addition to meeting the above-mentioned required performance, it is also important that the recording material for inkjet recording has an appropriate degree of bleeding so that the ink dots recorded in a pixel of a predetermined size spread uniformly over the entire pixel. is required.

For example, when ordinary high-quality paper is used as a recording material, it has poor ink absorption properties, making it impossible to obtain a sufficiently large ink dot diameter, the shape of the ink dots being extremely poor, and the desired pixel density being unable to be obtained uniformly. Commercially available non-coated paper
Although the ink absorption is sufficient, the ink runs along the m fibers of the paper.

The degree of bleeding is non-uniform within the paper surface, it is difficult to control the shape and size of the ink dots, and local variations in ink dot density occur, making it impossible to obtain sufficient pixel density.

It is an object of the present invention to satisfy the above requirements, to have high ink absorbency, and to have an appropriate degree of bleeding so that ink dots recorded in a pixel of a predetermined size spread uniformly over the entire pixel. However, it is an object of the present invention to provide an inkjet recording material that provides a good ink dot shape and has excellent color development.

The above object is achieved by the present invention as follows.

That is, the present invention is a recording material for inkjet recording, characterized in that the surface layer in the thickness direction of the recording material is made of a mixture of a filler and a fibrous material.

The recording material of the present invention is characterized by the unique structure of the surface layer portion of the recording material that receives ink.

That is, the recording material of the present invention basically mainly contains #li
It has a base material made of fibrous material and filler particles attached to the surface of the base material in a very thin manner, and the surface layer of the recording material receives the ink of the recording material. The portion is formed by a mixture of at least the filler particles and a portion of the fibers constituting the base material.

FIG. 1 is a schematic partial cross-sectional view of a typical example of the recording material of the present invention, taken perpendicular to the thickness direction of the surface layer portion of the recording material.

As shown in FIG. 1, the recording material of the present invention basically has 1
It has a surface layer portion 3, a middle layer portion 2, and a lower layer portion l.

The surface layer portion 3 is made up of a mixture of at least filler particles 6 and a portion of the fibers RA5 of the base material 4 mainly made of a fibrous material, and is a portion that mainly receives ink during recording.

The middle layer part 2 is located below the surface layer part 3 and is made of a base material 4, without filler particles 6, and mainly made of fibers 5, and this part hardly absorbs ink.

The lower layer portion 1 is a portion located below the middle layer portion 2,
The middle layer portion 2 and the middle layer portion 2 may be composed of one type of base material 4, or may be composed of a different base material from the base material 4 constituting the middle layer portion 2, or a suitable support.

The filler particles 6 are attached to the base material 4 mainly by a binder (not shown).
It adheres and sticks to the surface as if it were sprinkled very thinly on the surface. In the surface layer portion 3, some portions of the fibers 5 are lightly covered with filler particles 6, while other portions are in direct contact with the outside world. The filler particles 6 not only lightly cover the fibers 5 but also penetrate into the gaps between the fibers 5. In this way, the surface layer portion 3 of the recording material of the present invention is formed, in which at least part of the fibers 85 of the fibrous material that mainly constitutes the base material 4 and the filler particles 6 are mixed.

FIG. 2 is a scanning electron micrograph of the surface layer of an example of the recording material of the present invention, taken at a magnification of 1500 times, of a cross section taken perpendicular to the thickness direction of the recording material, in which filler particles are mainly formed. The adhesive (not shown) adheres and fixes to the surface of the base material in a very thin manner as if it is scattered, and the fibers that mainly constitute the filler particles and the base material are attached to the surface layer of the recording material in the thickness direction. The condition of the surface layer portion of the recording material of the present invention, in which a portion of .

On the other hand, Figure 3 shows the same magnification of the cut surface of the surface layer of a conventional recording material (product name: inkjet paper, manufactured by Mitsubishi Paper Mills Co., Ltd.) cut perpendicular to the thickness direction of the recording material. This is an electron micrograph. Figure 3 clearly shows the structure of the surface layer of this recording material, where countless pulp fibers overlap.
It is clearly distinguished from the recording material of the present invention.

When recording with ink is performed on the surface layer portion of the recording material of the present invention, the ink adhering to the surface of the recording material mainly forms the surface layer portion 3 in which $145 and filler particles 6 are mixed. absorbed into. Then, it is hardly absorbed into the middle layer portion 2 inside the recording material, that is, hardly absorbed in the thickness direction of the recording material, and spreads in the surface layer portion 3 in the horizontal direction.

This is because the filler particles are smaller than the fibers, so the specific surface area (surface area per unit weight) of the filler particles is naturally larger than the fibers.On the other hand, ink (recording liquid) has a surface area of the filler or fibers. The energy is absorbed into the recording material. The ink is then absorbed faster in the areas formed by a large number of filler particles that have more surface energy, ie, a larger surface area, than in the areas made of fibers. Therefore, in the recording material of the present invention, the filler particles are adhered to the surface layer in a very thinly dispersed manner, so that the surface area of the surface layer 2 is larger than the inside of the recording material. Because of the difference in absorption speed, the ink can travel faster in the lateral direction than in the thickness direction of the recording material. Therefore, the recording material of the present invention has a large ink smear, a fast ink absorption, and can record sufficiently large ink dots within the above-mentioned predetermined size pixels.

As the base material 4 mainly made of fibrous material of the recording material of the present invention, it is appropriate to use paper, but cloth, synthetic paper, etc. can also be used. In order to suppress the ink absorption in the thickness direction of the recording material as described above, it is recommended to use a base material 4 made of a fibrous material whose liquid absorption is suppressed by a method such as sizing. preferable.

For the lower layer portion 1 of the present invention, in addition to the paper, cloth, or synthetic paper used for the base material 4, materials that can be used as a suitable support such as a resin film can be used.

On the other hand, one of the other components that basically constitutes the surface layer portion 3 of the recording material of the present invention is the filler 6 fixed to the surface of the base material 4 mainly by a binder.

Examples of the filler include silica, clay, talc, carrion, diatomaceous earth, calcium carbonate, calcium sulfate,
Examples include satin white, aluminum silicate, alumina, zeolite, etc., and one or more of these is used.

Particles of the filler are fixed onto the base material so that some of the fibers 5 mainly constituting the base material 4 and the filler 6 are mixed on the surface layer 3 of the recording material. In order to provide good ink absorbency and degree of bleeding to the surface portion of the recording material, the particle size of the filler used is preferably about 0.14 m to 20 μs, rather than 0.05 μm to 50 −1. This is desirable. If the particle size of the filler is too large, the degree of ink bleeding in the horizontal direction of the recording material becomes uneven, making it difficult to control the size and shape of the dots, which is not preferable.

Furthermore, if a porous filler is used as the filler 6, the ink adhering to the surface of the recording material will penetrate into the porous filler, and the recording agent components of the ink (for example, dyes and pigments) will penetrate into the porous filler.
Good coloring properties can be obtained by being adsorbed by the porous filler.

On the other hand, the binder for fixing the filler to the surface of the base material 4 includes starch, gelatin, casein, gum arabic,
Water-soluble polymers such as sodium alginate, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, and polyacrylamide; synthetic resin latex such as synthetic rubber latex, polyvinyl butyral, polyvinyl chloride, polyvinyl acetate,
Examples include organic solvent-soluble resins such as polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide, phenol resin, polyurethane, and alkyd resin. In addition, the surface layer portion 3 of the recording material of the present invention may contain other pigments such as plastic pigments, dispersants, fluorescent dyes, P)l adjustment together with the above-mentioned filler, to the extent that the effects of the present invention are not impaired. Various additives such as antifoaming agents, antifoaming agents, lubricants, preservatives, and surfactants can also be mixed.

The recording material of the present invention can be obtained by applying a coating liquid prepared by dispersing ingredients mainly consisting of these fillers and a binder in a medium such as water using a roll coating method, a rod bar coating method,
It can be manufactured by coating on a substrate by a spray coach ink method, an air knife coating method, etc., and then drying it as quickly as possible.

As for the mixing ratio of the filler and the binder in the coating liquid, it is generally appropriate that the binder is 100 to 150 parts by weight per 100 parts by weight of the filler, and when the average particle size of the filler is large,
Good results are obtained by using as little binder as possible. The coating amount of components including fillers, binders, etc. that are fixed on the substrate is determined by the desired dot diameter and the amount of ink that forms one ink dot and the size of the pixel in which the ink dot is recorded. Selected by. That is, by reducing the coating amount of these components, larger ink dots can be obtained. The amount of coating is usually selected from the range of about 1 to 30 g/rn' (dry coating amount), and the thickness of the surface layer portion 3 is (1.5 scales to l
It becomes about Oμ.

As described above, the recording material of the present invention, which has a unique structure in the surface layer portion of its cut surface, has high ink absorbency.
In addition, ink dots recorded in a pixel of a predetermined size have an appropriate degree of smearing so that they spread uniformly over the entire pixel, and a good ink dot shape is obtained, so that sufficient pixel density can be obtained and coloration can be achieved. This is an inkjet recording material with excellent properties.

Furthermore, by using the recording material of the present invention, when the same amount of ink is used, by changing the amount of coating components, it is possible to adjust the ink dot diameter to a desired size that adapts to the width of the pixel. It became possible to control the size. Furthermore, compared to conventional recording materials, larger ink dots can be obtained, recording can be performed using a larger pixel area, and the recording speed can be increased.

Hereinafter, the present invention will be explained in more detail according to Examples. Example 1 As a filler, 'fRflll calcium (average particle size: l
Using u), a coating composition was prepared based on the following composition using starch and SBR latex as a binder.

Calcium carbonate too Part by weight Starch 3Q tt SBR latex 1o〃 Water 300 tt On the other hand, general high-quality paper with a sizing degree of 35 seconds based on JIS P 5t22 (basis weight 85 g/rn
'), the above-mentioned coating composition was coated onto this support by a blade coater method at a dry coating amount of 3 g/rrf, and dried by a conventional method to obtain a recording material. 1 of the cut section cut perpendicularly to the thickness direction of the obtained recording material
A scanning electron micrograph at 500x magnification is shown in Figure 2.

For this recording material, the following four colors of ink were used, the drop left diameter was 110Q, and the pixel size was 300 x 300.
Color inkjet recording was performed under the following recording conditions, and the recording characteristics of the recording material were evaluated.

Yellow ink (composition) C, 1, acid yellow 23 2 parts by weight diethylene glycol 30 tt water 70 tt magenta ink (composition) c, r, 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 30 // Water 70 l / Black ink (composition) C, 1, Ti Left Black 19 2 Parts by weight Diethylene glycol 3011 Water 70 // The evaluation results of the recording characteristics of the recording material are shown in Table 1. show.

When evaluating the recording characteristics in Table 1, 1) Pixel density was measured by measuring the reflective optical density when all pixels were recorded using a photographic densitometer NLM-9TD-Tr (manufactured by Narumi Shokai).

2) To determine the dot shape, observe the printed dots with a stereomicroscope. If the dot is slightly round, mark it as 0. If the circle is slightly distorted, mark it as Δ.
Irregular shapes were marked as ×.

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 clarity was determined by visually comparing the color clarity of the inkjet recorded images, and ranking the best one as ■, the worst as ×, and ranked O, O1Δ, and X.

5) Ink absorbency is measured when two colors of ink are overlaid and recorded.
lOthers were marked as ×.

Example 2 Using silica (trade name: Nibsil E220A, manufactured by Nippon Silikani Industry Co., Ltd., average particle size 1.0) as a filler and polyvinyl alcohol and SBR latex as a binder, 8 coatings were applied based on the following composition. An industrial composition was prepared.

Silica 100 parts by weight Polyvinyl alcohol 25 SBR latex 5 Water 500 tt On the other hand, as the ta fibrous base material, the same general high-quality paper as in Example 1 was used, and the above coating composition was dried on this support. A recording material was obtained by coating with a coating amount of 2 g/rn' using a blade coater method and drying by a conventional method.

A scanning electron micrograph of a section cut perpendicularly to the thickness direction of this recording material at a magnification of 1500 times was almost the same as that obtained in Example 1 shown in FIG.

The recording characteristics of this recording material were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 A coating composition was prepared based on the following composition using talc (average particle size 1 u) as filler particles and casein as a binder.

Talc 100 parts by weight Casein 20 Water 500 /1 On the other hand, as the fibrous base material, the same high-quality paper as in Example 1 was used, and the above coating composition was applied on this support in a dry coating amount of 2 g. /rrf by a blade coater method and dried by a conventional method to obtain a recording material.

A scanning electron micrograph of a section cut perpendicularly to the thickness direction of this recording material at a magnification of 1500 times was almost the same as that obtained in Example 1 shown in FIG.

The recording characteristics of this recording material were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 Inkjet recording characteristics were evaluated in the same manner as in Example 1 using commercially available inkjet paper (trade name: Inkjet Paper, manufactured by Mitsubishi Paper Mills Co., Ltd.) as a recording material. The results are shown in Table 1. In addition, 15 mm of the cut surface section cut perpendicularly to the thickness direction of this inkjet paper
A scanning electron micrograph at 00x magnification is shown in Figure 3.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a cross section of an example of the recording material of the present invention taken along a νJ cut perpendicular to the thickness direction of the recording material. The 21st Δ is a 1500x scanning electron micrograph of a Gino cross section cut perpendicularly to the thickness direction of an example of the recording material of the present invention;
FIG. 3 is a 1500x scanning electron micrograph of a cross section of a conventional inkjet paper cut perpendicularly to the thickness direction. In the figure, l is the lower layer of the material to be recorded, 2 is the middle layer of the material to be recorded, 3 is the surface layer of the material to be recorded, 4 is the base material mainly made of fibrous material, 5 is the fiber, 6 is a filler. Figure 1 Procedures Amendment (Method) February 28, 1980 Director General of the Patent Office Sir 1, Indication of Case 1981 Patent Application No. 171378
No. 2, Name of the invention Recorded material 3, Person making the amendment Relationship to the case Patent applicant (100) Canon Co., Ltd. 4, Agent address: 1-9-20-5 Akasaka, Minato-ku, Tokyo, Roy of the amendment order 1 Dispatched on January 31, 1980 7, Contents of amendment (1) On page 21 of the specification, lines 4 to 6, “-Example thickness direction... Scanning electron micrograph ,” should be changed to “−
The example has been corrected to read ``Photograph substituted for a drawing taken with a scanning electron microscope at a magnification of 1500 times to show the particle shape of filler particles in a cross section cut perpendicularly to the thickness direction of a recording material.'' (2) “Cut surface portion/
・・・・・・・・・This is a photo. '' should be corrected to ``This is a similar drawing-substituting photograph taken by a scanning electron microscope at the same magnification as the drawing-substituting photograph in Figure 2 of the cut section.''

Claims (1)

[Claims] 1. A recording material for inkjet recording, characterized in that the surface layer in the thickness direction of the recording material is made of a mixture of a filler and a fibrous material.