JPH07179028A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE:To provide an ink jet recording sheet having high glossiness and smoothness, imparting high image density and excellent in ink absorbability. CONSTITUTION:In an ink jet recording sheet wherein an ink receiving layer is provided on a support, a coating soln. based on a mixture of gelatin and a water-soluble cellulose derivative and having viscosity of 5-100 cps at 35 deg.C is applied to a liquid non-absorbable support and dried to form the ink receiving layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording sheet on which an image is formed by an inkjet printer. More specifically, it relates to an inkjet recording sheet having high gloss, smoothness and image density and excellent in ink absorbability.

[0002]

2. Description of the Related Art Ink jet recording is a system in which minute droplets of ink are ejected by various operating principles and adhered to a recording sheet such as paper to record images, characters and the like. Inkjet printers have features such as high-speed printing, low noise, high flexibility in recording patterns, and no need for development or fixing, so that complex images can be formed accurately and quickly. In recent years, it has been rapidly popularized for various purposes, especially as a hard copy creating apparatus for image information such as characters and various figures created by a computer.

Further, in the ink jet recording method, it is easy to perform multicolor recording by using a plurality of ink nozzles. In the multicolor inkjet recording system,
Compared to multicolor printed matter and color photographs, it is possible to obtain an image that is comparable to that of multicolored printed matters and color photographs. Further, in applications where the number of copies is small, it is cheaper than printing technology and photographic technology, and is therefore being widely used.

In recent years, the fields of use of ink jet printers, which have received a great deal of attention, include the production of color proofs and the output of design images in the design field in the printing field where high image quality close to that of photographs is required. Furthermore, it is also common practice to output characters and image information created by a computer to a transparent recording sheet using an inkjet printer and use this as an original for an overhead projector for presentations at conferences.

The characteristics required for the recording sheet used in such an ink jet recording system are that the surface of the ink receiving layer has a high gloss, the image density is high, the color reproducibility is good, and the ink absorbability is high. And high dot reproducibility.

As a conventionally known technique, for example, Japanese Patent Publication Sho
61-60793, JP 3-215081 JP, etc., silica,
An inkjet recording sheet having an ink receiving layer composed of an inorganic pigment such as colloidal silica, alumina sol and calcium carbonate and a water-soluble binder such as oxidized starch, polyvinyl alcohol, carboxymethyl cellulose and polyacrylic acid is disclosed. However, the above-mentioned inkjet recording sheet was not always at a level where the gloss and smoothness of the surface of the ink receiving layer, the image density, and the ink absorbency were satisfactory.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording sheet having high gloss, smoothness and image density which could not be realized by the prior art and which is excellent in ink absorption. .

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a coating liquid having a specific viscosity mainly composed of a mixture of gelatin and a water-soluble cellulose derivative. After coating on a non-liquid-absorbent support and drying, a very smooth ink-receiving layer is formed and high gloss is obtained, and the transparency of the ink-receiving layer is high, resulting in high print density. It was found that an inkjet recording sheet having good ink absorbency can be obtained, and the present invention has been completed.

That is, the ink jet recording sheet of the present invention is an ink jet recording sheet in which an ink receiving layer is provided on a support, the support is non-liquid absorbing, and the ink receiving layer coating liquid is gelatin and water-soluble. Mainly composed of a mixture of water-soluble cellulose derivatives and having a viscosity at 35 ° C. of 5 to 10
It is characterized by being 0 cps.

In the present invention, the support is provided in order to prevent deterioration of surface quality due to swelling of the support during coating of the ink receiving layer.
It is preferably non-liquid absorbent. As such a support, a film, a metal foil, a resin-coated paper or a composite thereof can be used. However, since the surface quality and handleability are good and the photograph-like texture is provided, the use of a resin-coated paper is preferred. Is particularly preferable. The thickness of the support is not particularly limited, but it is preferably about 50 to 300 μm from the viewpoint of handleability and suitability for passing paper through the printer.

Before the ink receiving layer is applied to the support, an undercoat layer may be provided to improve the coating property of the ink receiving layer coating liquid. To such an undercoat layer, pigments, various water-soluble polymers, latexes, hardeners, surfactants and the like can be appropriately combined and added.

In the present invention, the ink receiving layer is preferably composed mainly of a mixture of gelatin and a water-soluble cellulose derivative in order to obtain high transparency and ink absorbability.

Examples of gelatin include lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, phthalated gelatin, maleated gelatin, and fumarized gelatin.

Examples of the water-soluble cellulose derivative include carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose and viscose.

The weight ratio of gelatin to the water-soluble cellulose derivative in the ink receiving layer is preferably in the range of 10:90 to 90:10. When the weight ratio of gelatin to the water-soluble cellulose derivative is less than 10:90, the image density is lowered, which is not preferable. On the other hand, when it is larger than 90:10, the ink absorbency is lowered, which is not preferable.

In the ink receiving layer, in addition to gelatin and a water-soluble cellulose derivative, silica, colloidal silica, alumina sol, silicon resin particles, polystyrene resin particles, transparent pigments such as starch particles, polyvinyl alcohol, starch, polyvinylpyrrolidone. , Polyvinylpyridinium halide, sodium polyacrylate, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether-maleic acid copolymer, styrene-maleic acid copolymer, polyacrylamide, polyethyleneimine, melamine resin, urea resin, polyamide resin Water-soluble resins such as, anionic, cationic, nonionic, amphoteric surfactants, active halogen compounds, vinyl sulfone compounds, aziridine compounds, epoxy compounds, acrylics Yl compounds, hardeners such as isocyanate compounds, preservatives, dyes, fluorescent agents, ultraviolet absorbers, antioxidants, antiblocking agents, pH adjusting agents, may be added in appropriate combination defoaming agent.

In the present invention, the ink receiving layer coating liquid is 3
The viscosity at 5 ° C is preferably 5 to 100 cps. When the viscosity at 35 ° C. is lower than 5 cps, the flow of air during drying causes unevenness on the surface of the ink receiving layer, resulting in poor smoothness. On the other hand, when it is higher than 100 cps, the unevenness generated at the time of coating is not easily made uniform, so that the smoothness of the surface of the ink receiving layer after drying is deteriorated.

The dry coating amount of the ink receiving layer is 1
It is preferably ˜50 g / m ² . When the coating amount of the ink receiving layer is less than 1 g / m ² , the ink absorbability is poor, and thus the ink after printing overflows from the ink receiving layer, and the image is liable to be mixed with color or rubbed. Again 5
If it exceeds 0 g / m ² , problems such as coloring of the ink receiving layer and curling of the recording sheet occur.

In the present invention, the ink receiving layer is coated on the support by a general coating device such as a rod, wire bar, slide hopper, curtain, extrusion die, air knife, roll or blade.
The use of a slide hopper is particularly preferred because it gives a very smooth coated surface like a mirror.

The ink receiving layer may be either a single layer or a multilayer of two or more layers. In the case of multiple layers, each layer may have a different composition or the same composition. When forming multiple layers, two or more layers may be coated at once or one layer at a time.

Further, the ink receiving layer is provided on at least one side of the support, but it may be provided on both sides of the support for the purpose of performing double-sided printing or preventing curling.

In the present invention, a backing layer may be provided on the side of the support opposite to the ink receiving layer in order to impart antistatic properties, transport properties, curl prevention properties and the like. An inorganic or organic antistatic agent, a water-soluble binder, a synthetic resin latex, a film-hardening agent, a pigment, a surfactant and the like can be appropriately combined and added to such a backing layer.

Such a back coating layer is coated on the support by a general coating device such as a rod, a wire bar, a slide hopper, a curtain, an extrusion die, an air knife, a roll and a blade.

[0024]

According to the present invention, a non-liquid absorbent support is coated with a coating liquid having a specific viscosity, which is mainly composed of a mixture of gelatin and a water-soluble cellulose derivative, and then dried to obtain a very smooth surface. The ink receiving layer is formed to obtain high gloss, and the ink receiving layer has high transparency, so that an ink jet recording sheet having high print density and good ink absorbability can be obtained.

[0025]

The present invention will be described in detail below with reference to examples, but the contents of the present invention are not limited to these examples.

Example 1 A resin composition comprising 85 parts by weight of low-density polyethylene and 15 parts by weight of titanium dioxide by melt extrusion method after corona discharge treatment was applied to the surface of a high-quality paper made of LBKP having a basis weight of 100 g / m ² . Of 16 g / m ² and corona discharge treatment on the back side, and then a resin composition consisting of 60 parts by weight of high-density polyethylene and 40 parts by weight of low-density polyethylene is applied.
g / m ^{2 was} applied to prepare a resin-coated paper support.

After the corona discharge treatment was applied to the surface of the resin-coated paper, a dry coating amount of an ink receiving layer coating liquid having a solid content concentration of 15% of the following composition was 7 g / m using a slide hopper.
^An ink jet recording sheet was prepared by coating and drying so as to be ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was measured using a B-type viscometer (60 rpm), and it was 97 cps. <Ink Receiving Layer Coating Composition 1> Gelatin 5 parts by weight Carboxymethyl cellulose 95 parts by weight Sulfosuccinic acid octyl ester 0.1 parts by weight

Example 2 In the same manner as in Example 1 on the support of Example 1, a dry coating amount of the ink receiving layer coating solution having the following composition and a solid content of 10% was applied.
An inkjet recording sheet was prepared by coating and drying so as to have g / m ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was measured using a B-type viscometer (60 rpm), and it was 51 cps. <Ink-Receptive Layer Coating Composition 2> Gelatin 15 parts by weight Carboxymethyl cellulose 85 parts by weight Sulfosuccinic acid octyl ester 0.1 parts by weight

Example 3 In the same manner as in Example 1, an ink receiving layer coating liquid having a solid content concentration of 10% having the following composition was applied onto the support of Example 1 in a dry coating amount of 7:
An inkjet recording sheet was prepared by coating and drying so as to have g / m ² . The viscosity of the coating liquid for this ink receiving layer at 35 ° C. was 42 cps when measured with a B-type viscometer (60 rpm). <Ink Receptor Layer Coating Composition 3> Gelatin 50 parts by weight Carboxymethyl cellulose 50 parts by weight Octyl sulfosuccinate ester 0.1 parts by weight

Example 4 In the same manner as in Example 1, an ink receiving layer coating liquid having a solid content concentration of 10% and having the following composition was applied onto the support of Example 1 in a dry coating amount of 7:
An inkjet recording sheet was prepared by coating and drying so as to have g / m ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was 33 cps when measured with a B-type viscometer (60 rpm). <Ink receiving layer coating liquid formulation 4> Gelatin 85 parts by weight Carboxymethyl cellulose 15 parts by weight Sulfosuccinic acid octyl ester 0.1 parts by weight

Example 5 In the same manner as in Example 1, an ink receiving layer coating solution having a solid content of 5% and having the following composition was dried on the support of Example 1 to give a dry coating amount of 7 g.
The ink-jet recording sheet was prepared by coating and drying so as to be / m ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was measured with a B-type viscometer (60 rpm), and it was 7 cps. <Ink Receiving Layer Coating Liquid Formulation 5> Gelatin 95 parts by weight Carboxymethyl cellulose 5 parts by weight Sulfosuccinic acid octyl ester 0.1 parts by weight

Example 6 In the same manner as in Example 1, an ink receiving layer coating liquid having a solid content concentration of 10% having the following composition was applied onto the support of Example 1 in a dry coating amount of 7%.
An inkjet recording sheet was prepared by coating and drying so as to have g / m ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was 38 cps when measured with a B-type viscometer (60 rpm). <Ink receiving layer coating liquid formulation 6> Gelatin 50 parts by weight Hydroxyethyl cellulose 50 parts by weight Octyl sulfosuccinate ester 0.1 parts by weight

Example 7 After subjecting the surface of the support of Example 1 to corona discharge treatment,
An ink jet recording sheet was prepared by applying the ink receiving layer coating liquid of Example 3 using a reverse roll coater so that the dry coating amount was 7 g / m ² and drying.

Example 8 After the surface of a 100 μm thick white polyethylene terephthalate film was subjected to corona discharge treatment, the coating liquid for the ink receiving layer of Example 3 was dried to a coating amount of 7 g / m ² using a slide hopper. And then dried. Next, the ink-receiving layer coating liquid of Example 3 was applied to the back surface in the same manner so that the dry coating amount was 7 g / m ² , and dried to prepare an inkjet recording sheet.

Comparative Example 1 The coating liquid of the ink receiving layer of Example 3 was applied to the surface of a high-quality paper made of LBKP having a basis weight of 100 g / m ^{2 so} that the dry coating amount was 7 g / m ^2. Then, it was dried to prepare an inkjet recording sheet.

Comparative Example 2 An ink receiving layer coating solution having a solid content concentration of 18% and having the same composition as in Example 3 was dried on the support of Example 1 to a coating amount of 7 g / m ² . Thus, an inkjet recording sheet was prepared by coating and drying. The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was measured with a B-type viscometer (60 rpm), and it was 112 cps.

Comparative Example 3 On the support of Example 1, the same coating composition as in Example 3 and an ink receiving layer coating solution with a solid content concentration of 3% was applied on the support of Example 1 to give a dry coating amount of 7 g / m ² . Thus, an inkjet recording sheet was prepared by coating and drying. The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was measured using a B-type viscometer (60 rpm), and it was 3 cps.

Comparative Example 4 On the support of Example 1, a dry coating amount of an ink receiving layer coating liquid having a solid content concentration of 10% and having the following composition was applied in the same manner as in Example 1.
An inkjet recording sheet was prepared by coating and drying so as to have g / m ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was measured using a B-type viscometer (60 rpm), and it was 60 cps. <Ink Receptive Layer Coating Composition 7> Carboxymethylcellulose 100 parts by weight Sulfosuccinic acid octyl ester 0.1 parts by weight

Comparative Example 5 In the same manner as in Example 1, an ink receiving layer coating liquid having a solid content concentration of 10% having the following composition was applied onto the support of Example 1 in a dry coating amount of 7:
An inkjet recording sheet was prepared by coating and drying so as to have g / m ² . The viscosity of the coating liquid for the ink receiving layer at 35 ° C. was 25 cps when measured with a B-type viscometer (60 rpm). <Ink Receptive Layer Coating Composition 8> Gelatin 100 parts by weight Sulfosuccinic acid octyl ester 0.1 parts by weight

These inkjet recording sheets were evaluated for the following items, and the results are summarized in Table 1.

[Glossiness] The glossiness of the ink jet recording sheet surface was measured according to the method defined in JIS-P8142.

[Smoothness] Oblique light was applied to the ink jet recording sheet to visually observe the surface smoothness. ◯: Very smooth, Δ: Slightly poor smoothness, but practically no problem, ×: The smoothness was poor, and it was not practically usable.

[Image Density] HEWLETT PACKA
An image was printed using a Desk Writer 550C printer manufactured by RD and the optical density of a 100% printed portion of magenta was measured by a Macbeth RD-914 reflection densitometer.

[Ink Absorption] HEWLETT PAC
Printing is performed using a KARD Desk Writer 550C printer, and the ink overflow state of the 100% printed portion of magenta is visually observed. ○: Ink overflow is not observed, Δ: Ink overflow is slightly observed, but practical The limit is ×: Ink overflow is so severe that it cannot be put to practical use.
It was evaluated in three stages.

[0045]

[Table 1]

As is clear from the results shown in Table 1, all the ink jet recording sheets of Examples 1 to 8 according to the present invention had high gloss, smoothness and image density, and showed excellent ink absorbability. However, in the inkjet recording sheet of Comparative Example 1, since the liquid-absorbent high-quality paper was used as the support, the surface was roughened due to the swelling of the support when the ink receiving layer was applied, and the glossiness was lowered. In the inkjet recording sheet of Comparative Example 2, since the viscosity of the ink receiving layer coating liquid was too high, the unevenness generated during coating was not uniformed, and the smoothness of the ink receiving layer surface was lowered. In the inkjet recording sheet of Comparative Example 3, since the viscosity of the ink receiving layer coating liquid was too low, unevenness due to the flow of air during drying occurred, and the smoothness of the ink receiving layer surface decreased. In the inkjet recording sheet of Comparative Example 4, the image density was lowered because the composition of the ink receiving layer was carboxymethyl cellulose alone. In the ink jet recording sheet of Comparative Example 5, since the composition of the ink receiving layer was gelatin alone, the ink absorbability was lowered.

[0047]

According to the present invention, an ink jet recording sheet having high gloss, smoothness and image density and excellent ink absorbency can be obtained.

Claims (2)

[Claims] 1. An inkjet recording sheet having an ink-receiving layer provided on a support, wherein the support is non-liquid-absorbent, and the coating liquid for the ink-receiving layer is mainly composed of a mixture of gelatin and a water-soluble cellulose derivative. An inkjet recording sheet having a viscosity at 35 ° C. of 5 to 100 cps. 2. The ink jet recording sheet according to claim 1, wherein the ink receiving layer is applied onto the support by a slide hopper and dried.