JPH05278321A - Production of material to be recorded for ink jet recording - Google Patents

Abstract

PURPOSE:To impart a good ink dot shape and to improve color developability by providing a surface layer containing a filler and a binder in specific amounts on a fibrous base material and exposing a part of a fibrous material to the surface of the surface layer. CONSTITUTION:A coating solution is prepared by dispersing at least a filler and a binder in a medium such as water in a wt. ratio of 10/1-10/15 and applied to a fibrous base material 4 and dried to produce a material to be recorded for ink jet recording having a surface layer 3 wherein the filler 6 and the fibrous material 5 of the base material are mixed and a part of the fibrous material 5 is exposed to the surface thereof. Concretely, in this material to be recorded, filler particles 6 are thinly bonded and fixed to the surface of the base material 4 by the binder and the surface layer 3 has parts where the fibrous material 5 is lightly covered with the filler particles 6 or directly in contact with the outside. The surface layer 3 has function mainly receiving ink at the time of recording. The coating amount of the coating solution to the base material 4 is set to 1-5g/m<2> as a dry coating amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a recording material (recording paper) used in an ink jet recording method,
The present invention relates to a method for producing a recording material for inkjet recording, which has a high ink (recording liquid) absorbency, an appropriate degree of bleeding, a good ink dot shape, and a high pixel density.

[0002]

2. Description of the Related Art Ink jet recording methods generate small ink droplets by an ink ejection method such as an electrostatic suction method by applying a high voltage or a method of applying mechanical vibration or displacement to ink by using a piezoelectric element. Recording is performed by flying and adhering it to a recording material such as paper, and is a recording method capable of high-speed printing and multicolor printing with less noise generation.

As ink for ink jet recording,
From the viewpoint of safety and printability, mainly water-based products are used.
Generally, it contains a recording agent and a liquid medium.

As a recording material used in this ink jet recording method, ordinary paper has been generally used. However, with the improvement of the performance of the inkjet recording machine such as the speeding up of recording or the multicolor recording, more advanced characteristics are required for a recording material for inkjet recording.

As such a recording material for inkjet recording, 1) the absorption of ink is as quick as possible, 2) when the ink dots overlap, the ink that adheres later flows to the previous dot. 3) The diameter of the ink dot is uniform and has a desired size, 4) The shape of the ink dot is close to a perfect circle and its periphery is smooth, 5) The whiteness is high, 6) It is required that the colorability of the coloring component of the ink is excellent and that the required performance such as

On the other hand, when recording on a recording material by the ink jet recording method, generally, an image to be recorded (original image) is equally subdivided, and one unit (pixel) of the subdivided image. ) Is represented by one ink dot or a plurality of ink dots during recording, the original image is reproduced on the recording material. In such a recording system, it is necessary to obtain a sufficient pixel density (recording density of one pixel as a whole) in order to give a sufficient recording density to a recorded image. For this purpose, for example, a case where one pixel is represented by one ink dot with the same amount of ink having the same recording agent concentration will be described. Ink dots recorded in one pixel are uniformly distributed over the entire one pixel as much as possible. It is preferably recorded so as to spread. because,
Generally, when an ink dot having a small diameter is printed in one pixel, the printing density of the ink dot itself is high, but the pixel density is low. On the other hand, when the diameter of the ink dot increases, the recording density of the ink dot itself decreases, but the pixel density increases. Then, the pixel density becomes maximum when the ink dots are uniformly spread over the entire pixel. This is because the pixel density is mainly defined by the relative relationship between the recorded portion and the non-recorded portion in one pixel.

Further, if recording is performed using a recording material having a greater degree of bleeding, recording can be performed using a larger pixel area and the recording speed can be increased.

Therefore, in addition to the above-mentioned required performance, the ink jet recording is performed in such a manner that the ink dot recorded in the pixel of a predetermined size has an appropriate degree of blurring so as to spread uniformly over the entire pixel. Required for recording material.

For example, when ordinary high-quality paper is used as the recording material, the ink absorbency is poor and a sufficiently large ink dot diameter cannot be obtained, the shape of the ink dot is extremely poor, and the desired pixel density is obtained uniformly. I can't. In addition, commercially available uncoated paper has sufficient ink absorbency, but the ink runs along the fibers of the paper and the degree of bleeding is uneven within the paper surface, and the shape and size of the ink dots are controlled. It is difficult to do so, and there is a partial variation in the ink dot density, and a sufficient pixel density cannot be obtained.

Further, as an ink jet recording paper, one having a constitution in which a coating layer containing a pigment such as silica is provided on a base paper is disclosed, for example, in JP-A-55-51583 and JP-A-5-51853.
As disclosed in JP-A-8-72495, these recording papers have been devised to suppress the spread of dots by providing a covering layer on the base paper, and it is not possible to obtain sufficient pixel density. Absent.

The object of the present invention is to satisfy the above-mentioned requirements, to have a high ink absorbency, and to appropriately spread the ink dots recorded in a pixel of a predetermined size uniformly over the entire pixel. An object of the present invention is to provide a method for producing a recording material for inkjet recording, which has a degree of bleeding, can obtain a good ink dot shape, and is excellent in coloration.

The above object can be achieved by the present invention described below.

That is, the method for producing a recording material for ink jet recording according to the present invention comprises a coating liquid containing at least a filler and a binder and having a weight ratio in the range of 10/1 to 10/15. A dry coating amount of 1 g / m ² or more and less than 5 g / m ² is applied on the base material, the filler and the fibrous material of the base material are mixed on the base material, and It is characterized by forming a surface layer in which a part of the fibrous material appears on the surface.

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

That is, this recording material basically has a base material mainly made of a fibrous material and filler particles adhered to the surface of the base material so as to be dispersed very thinly. The surface layer portion of the recording material that receives the ink of the recording material is a mixture of at least the filler particles and a part of the fibers constituting the base material.

Incidentally, the above-mentioned JP-A-55-51583.
The inkjet recording paper described in Japanese Patent Publication No. JP-A-2004-12069 is one in which silica powder and a coating layer containing a polymer binder are provided on a base paper, that is, the base paper is completely covered with the coating layer. This is to be clearly distinguished from the recording material obtained in the present invention having a surface layer in which a part of the fibrous material of the substrate appears on the surface, and the effect of the present invention can be obtained from the constitution of the recording paper of the publication. It is not possible.

The ink jet recording paper disclosed in JP-A-58-72495 also has a constitution in which the base paper is completely covered with a coating layer, and a part of the fibrous material of the base paper is used. It does not have a surface layer that also appears on the surface mixedly in the coating layer. Therefore, this recording sheet is clearly distinguished from the recording material obtained in the present invention, and the effect of the present invention cannot be obtained even if the recording sheet disclosed in the publication is used.

In Table 1 in the lower right column of page 3 of JP-A-58-72495, the coating amount of the coating liquid containing silica on the base paper is set to 5 g / m ² as a dry coating amount. Recording sheets are disclosed.

However, even with such a small coating amount, it is not possible to obtain the constitution of the recording material obtained in the present invention from the method described in the publication.

On the other hand, as described above, the recording material obtained in the present invention has a dry coating amount of 1 g / m on a fibrous base material and a coating liquid containing at least a filler and a binder. ^It is applied in a range of ² or more and less than 5 g / m ² and has a constitution including a surface layer having a characteristic structure. With such a constitution, the intended purpose of the present invention is achieved.

FIG. 1 shows a schematic partial sectional view of a surface layer portion of a typical example of the recording material obtained by the present invention, which is cut perpendicularly to the thickness direction of the recording material.

As shown in FIG. 1, the recording material obtained by the present invention basically has a surface layer portion 3, an intermediate layer portion 2 and a lower layer portion 1.

The surface layer portion 3 has at least the filler particles 6.
And a part of the fibers 5 of the base material 4 mainly made of a fibrous material are mixed, and is a part that mainly receives ink at the time of recording.

The middle layer portion 2 is located below the surface layer portion 3,
It is a portion composed of the base material 4, no filler particles 6 are present, and it is mainly composed of fibers 5, and this portion hardly absorbs ink.

The lower layer portion 1 is a portion located below the middle layer portion 2 and may be constituted by one kind of base material 4 together with the middle layer portion 2, or the base material 4 constituting the middle layer portion 2.
It may be constituted by a substrate different from or a suitable support.

The filler particles 6 are adhered and fixed to the surface of the base material 4 by a binder (not shown) as if they were scattered very thinly. Then, in the surface layer portion 3, the fiber 5
There are some portions that are lightly covered with the filler particles 6 and some portions that are in direct contact with the outside world. The filler particles 6 not only lightly cover the fibers 5, but also enter the gaps between the fibers 5. In this way, the surface layer portion 3 of the recording material in which at least a part of the fibers 5 of the fibrous material mainly constituting the base material 4 and the filler particles 6 are mixed is formed.

FIG. 2 is an enlarged partial cross-sectional view of the surface layer portion of the recording material obtained by the present invention when observed with a scanning electron microscope in a cutting direction perpendicular to the thickness direction of the recording material. (1500 times), and the filler particles are mainly adhered and fixed by a binder (not shown) to the surface of the base material as if they were dispersed in a very thin manner, and in the thickness direction on the surface layer of the recording material. The state of the surface layer portion of the recording material in which the filler particles and a part of the fibers constituting the substrate are mainly mixed is well shown.

On the other hand, FIG. 3 shows a conventional recording material (trade name;
Inkjet paper L, manufactured by Mitsubishi Paper Mills, Ltd.) is a magnified partial sectional view of the same magnification as above when observed with a scanning electron microscope of a cut surface cut perpendicularly to the thickness direction of the recording material in the surface layer portion. is there. FIG. 3 shows the structure of the surface layer of this recording material in which numerous pulp fibers are overlapped,
It is clearly distinguished from the recording material that can be obtained by the present invention.

When recording with ink is performed on the surface layer of the recording material obtained by the present invention, the ink adhered to the surface of the recording material is mainly composed of fibers 5 and filler particles 6. It is absorbed by the mixed surface layer portion 3. And
Almost no absorption in the middle layer portion 2 inside the recording material, that is, almost no absorption in the thickness direction of the recording material, spreads the surface layer portion 3 in the horizontal direction.

Since the filler particles are smaller than the fibers, the specific surface area (surface area per unit weight) of the filler particles is naturally larger than that of the fibers. On the other hand, the ink (recording liquid) is absorbed in the recording material by the surface energy of the filler or fibers. The ink then has a higher surface energy, i.e. is absorbed faster in the part formed by the larger number of filler particles with a larger surface area than in the part made of fibres. Therefore, in the recording material obtained by the present invention, since the filler particles adhere and adhere to the surface layer portion as if they were scattered very thinly, the surface area of the surface layer portion is larger than that inside the recording material. Due to the difference in the absorption speed, the ink can travel faster in the lateral direction than in the thickness direction of the recording material. Therefore, the recording material obtained in the present invention has a large ink bleeding and a rapid ink absorption, and it is possible to record a sufficiently large ink dot in the pixel of a predetermined size described above.

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

The lower layer portion 1 of the recording material in the present invention is
In addition to the paper, cloth, synthetic paper or the like used for the base material 4, a material 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 is the filler 6 which is fixed to the surface of the base material 4 mainly by a binder.

Examples of the filler include silica, clay, talc, kaolin, diatomaceous earth, calcium carbonate,
Calcium sulfate, satin white, aluminum silicate, alumina, zeolite and the like can be mentioned, and one or more of them can be used.

Particles of the filler 5 are fixed on the surface layer portion 3 so that a part of the fibers 5 mainly constituting the substrate 4 and the filler 6 are mixed and the recording material is recorded. In order to give good ink absorbability and bleeding degree to the surface portion of the material, the particle size of the filler used is 0.05 μm to 50 μm.
m, more preferably about 0.1 μm to 20 μm. If the particle size of the filling material is too large, the degree of ink bleeding in the horizontal direction of the recording material becomes uneven, and it becomes difficult to control the size and shape of the dots, which is not preferable.

Further, if a porous filler is used as the filler 6, the ink adhering to the surface portion of the recording material will penetrate into the porous filler, and the recording agent component of the ink (for example, dye or pigment). ) Is adsorbed on the porous filler to obtain good colorability.

On the other hand, as the binder for fixing the above-mentioned filler to the surface of the substrate 4, starch, gelatin, casein, gum arabic, sodium alginate, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, poly Water-soluble polymers such as acrylamide; synthetic resin latex such as synthetic rubber latex, polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide, phenol resin, polyurethane, alkyd resin, etc. The organic solvent-soluble resin of In the surface layer portion 3, other pigments such as a plastic pigment, a dispersant, a fluorescent dye, a pH adjuster, an antifoaming agent, a lubricant, and the like, together with the above-mentioned filler, are used as long as the effects of the present invention are not impaired.
Various additives such as preservatives and surfactants can be mixed.

The method of the present invention is, for example, a roll coating method, a rod bar coating method, or a spray method, in which a coating solution prepared by dispersing components mainly composed of these fillers and a binder in a medium such as water is used. The method has a step of coating the base material by a coating method, an air knife coating method or the like, and then drying it as quickly as possible.

The mixing ratio of the filler and the binder in the coating liquid is generally 10 to 150 parts by weight of the binder with respect to 100 parts by weight of the filler, and the average particle diameter of the filler is When large, it is advantageous to use as little binder as possible. The coating amount of the components including the filler and the binder fixed on the base material is a desired dot according to the amount of ink forming one ink dot and the size of the pixel on which the ink dot is recorded. It is selected according to the diameter. That is, it is possible to obtain larger ink dots by reducing the coating amounts of these components. The coating amount is usually selected from the range of about 1 to 30 g / m ² (dry coating amount), but as shown in Examples described later, the coating amount is 1 g / m ² or more and 5 g / m ² or more. less than m ² ,
For example, if it is about 3 g / m ^2, it is possible to reliably obtain the recording material having the surface layer having the above-mentioned characteristic structure. Further, the thickness of the surface layer portion 3 is about 0.5 μm to 10 μm.

As described above, the recording material obtained by the present invention has a unique structure in the surface layer portion at the cut surface, has a high ink absorbency, and is recorded in a pixel of a predetermined width. Since the formed ink dots have an appropriate bleeding degree that spreads uniformly over the entire pixel and a good ink dot shape can be obtained, a sufficient pixel density can be obtained and the recording property for inkjet recording is excellent. It is a material.

Further, by using the recording material obtained in the present invention, when the same amount of ink is used, the amount of the coating component is changed to adapt the ink dot diameter to the pixel size. It has become possible to control the desired size. Further, it is possible to obtain a larger ink dot than that of the conventional recording material, it is possible to perform recording using a larger pixel area, and it is possible to increase the recording speed.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[0043]

【Example】

Example 1 A coating composition was prepared based on the following composition using calcium carbonate (average particle diameter: 1 μm) as a filler and starch and SBR latex as a binder.

Calcium carbonate 100 parts by weight Starch 30 〃 SBR latex 10 〃 Water 300 〃 On the other hand, as a fibrous base material, general fine-quality paper with a size degree of 35 seconds based on JIS P 8122 (basis weight 65 g / m ² ).
The above coating composition was coated on this support by a blade coater method at a dry coating amount of 3 g / m ² and dried by a conventional method to obtain a recording material. FIG. 2 shows an enlarged partial sectional view (1500 times) of a cut surface portion obtained by cutting the obtained recording material perpendicularly to the thickness direction.

For the recording material, the following four color inks were used, the droplet diameter was 90 μm, and the pixel size was 300.
Color inkjet recording was performed under the recording condition of × 300, and the recording characteristics of the recording material were evaluated.

Yellow ink (composition) C.I. I. Acid Yellow 23 2 parts by weight Diethylene glycol 30 〃 Water 70 〃 Magenta ink (composition) C.I. I. Acid Red 92 2 parts by weight Diethylene glycol 30 〃 Water 70 〃 Cyan ink (composition) C.I. I. Direct Blue 86 2 parts by weight Diethylene glycol 30 〃 Water 70 〃 Black ink (composition) C.I. I. Direct Black 19 2 parts by weight Diethylene glycol 30 〃 Water 70 〃 Table 1 shows the evaluation results of the recording characteristics of the recording material. In the evaluation of the recording characteristics in Table 1, 1) Pixel density was measured by using a photographic densitometer NLM-STD-Tr (manufactured by Narumi Shokai) to measure the reflection optical density when recorded on all pixels. 2) Regarding the dot shape, when the printed dots were observed with a stereoscopic microscope, the circle was almost circular, the circle was slightly distorted, and the irregular shape was X. 3) The degree of bleeding was measured by measuring the diameter of the printed dot with a stereoscopic microscope and indicated by the multiple of the ink droplet. 4) With regard to color vividness, the color vividness of ink jet recorded images was visually compared, and the best one was marked with ⊚, the worst one was marked with x, and the rank was classified into ◎, ○, Δ, and x. 5) Regarding the ink absorbency, when the inks were overlaid and recorded, the ink did not flow out and the image having a clear image was evaluated as ◯, and the other cases were evaluated as x. Example 2 Silica (trade name: Nipsil E220A, manufactured by Nippon Silica Industry Co., Ltd., average particle size 1.0 μm) was used as a filler, and polyvinyl alcohol and SBR latex were used as a binder, and coating was performed based on the following composition. A composition was made.

Silica 100 parts by weight Polyvinyl alcohol 25 〃 SBR latex 5 〃 Water 500 〃 On the other hand, the same general fine paper as in Example 1 was used as the fibrous base material, and the above coating composition was applied on this support. Was coated by a blade coater method at a dry coating amount of 2 g / m ² and dried by a conventional method to obtain a recording material.

Scanning electron micrographs of the cross section of the recording material cut perpendicularly to the thickness direction at a magnification of 1500 were almost the same as those 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 Talc (average particle size 1 μm) was used as the filler particles,
Using casein as a binder, a coating composition was prepared based on the following composition.

Talc 100 parts by weight Casein 20 〃 Water 500 〃 On the other hand, as the fibrous base material, the same general fine paper as in Example 1 was used, and the coating composition was dried and coated on the support. A recording material was obtained by applying the composition at a rate of ² g / m ^{2 by} the blade coater method and drying it by a conventional method.

The scanning electron microscope photograph of the cut surface portion of the recording material cut perpendicularly to the thickness direction 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 by using a commercially available inkjet paper (trade name: inkjet paper L, manufactured by Mitsubishi Paper Mills, Ltd.) as a recording material. The results are shown in Table 1. Note that an enlarged partial cross-sectional view (1500 times) of a cut surface portion of the inkjet paper cut perpendicularly to the thickness direction is shown in FIG.

[0053]

[Table 1]

[0054]

According to the present invention, it has a unique surface structure,
It has a high degree of ink absorption, and has an appropriate degree of bleeding so that the ink dots recorded in a pixel of a predetermined size will spread evenly over the entire pixel, and a good ink dot shape can be obtained. It is possible to provide a recording material for inkjet recording which has a high density and is excellent in coloration.

Further, by using the recording material obtained by the present invention, when the same amount of ink is used, the amount of the coating component is changed to adapt the ink dot diameter to the pixel size. It has become possible to control the desired size. Further, it is possible to obtain a larger ink dot than that of the conventional recording material, it is possible to perform recording using a larger pixel area, and it is possible to increase the recording speed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an example of a recording material obtained according to the present invention in a direction perpendicular to a thickness direction.

FIG. 2 is an enlarged partial sectional view (1500 times) in a direction perpendicular to a thickness direction of an example of a recording material obtained by the present invention.

FIG. 3 is an enlarged partial cross-sectional view (1500 times) in a direction perpendicular to the thickness direction of a conventional inkjet paper.

[Explanation of symbols]

 1 Lower layer part of recording material 2 Middle layer part of recording material 3 Surface layer part of recording material 4 Base material 5 mainly made of fibrous material 5 Fiber 6 Filling material

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[Procedure amendment]

[Submission date] August 6, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

Calcium carbonate 100 parts by weight Starch 30 〃 SBR latex 10 〃 Water 300 〃 On the other hand, as a fibrous base material, general fine-quality paper with a size degree of 35 seconds based on JIS P 8122 (basis weight 65 g / m ² ).
The above coating composition was coated on this support by a blade coater method at a dry coating amount of 3 g / m ² and dried by a conventional method to obtain a recording material. FIG. 2 shows a partial cross section of a cross section of the obtained recording material which is perpendicular to the thickness direction and observed by enlarging (1500 times) with a scanning electron microscope.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

A cross section perpendicular to the thickness direction of this recording material is 1
When observed with a scanning electron microscope at a magnification of 500, it was almost the same as that obtained in Example 1 shown in FIG.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction content]

The cross section perpendicular to the thickness direction of this recording material is 1
When observed with a scanning electron microscope at a magnification of 500, it was almost the same as that obtained in Example 1 shown in FIG.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction content]

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 by using a commercially available inkjet paper (trade name: inkjet paper L, manufactured by Mitsubishi Paper Mills, Ltd.) as a recording material. The results are shown in Table 1. Note that FIG. 3 shows a partial cross section of a cross section of the ink jet paper perpendicular to the thickness direction when it is magnified (1500 times) with a scanning electron microscope and observed.

Claims (1)

[Claims] 1. A coating solution containing at least a filler and a binder and having a weight ratio in the range of 10/1 to 10/15 as a dry coating amount of 1 g / m ² on a fibrous base material. 5g or more
/ M ² is applied to form a surface layer in which the filler and the fibrous material of the base material are mixed on the base material and a part of the fibrous material appears on the surface. A method of manufacturing a recording material for inkjet recording, comprising: