JPH1110826A - Method for preparing block copy and recording sheet for block copy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make absorption of ink excellent and to enable attainment of printed matter having high color density and a clear image, by a method wherein print information is recorded on a recording sheet having a porous layer containing a pigment and a binder on a base by an ink jet type printing device, and a block copy is prepared from recorded matter thus obtained. SOLUTION: A recording sheet for a block copy is prepared by forming a porous layer containing a pigment and a binder on a base. Print information is recorded on this recording sheet for the block copy by using an ink jet type printing device, and the block copy is prepared by using recorded matter thus obtained. Then, an image thereof is picked up by using a camera for plate making, thereby preparing a film for plate making. Since higher transparency of an ink receptor layer is more desirable for increasing the color density of printed matter, a haze value serving as an index of the transparency of the porous layer is made 20% or below. Besides, the color density of the printed matter recorded on the recording sheet for the block copy by an ink jet recording method is made 1.3 or above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method for a printing plate and a recording sheet for preparing the printing plate.

[0002]

2. Description of the Related Art Conventionally, in the printing field such as offset printing, in the prepress process, a galley and an illustration of an original are pasted on a backing sheet to produce a copy. At this time, illustrations and other illustrations are drawn by various methods, so to ensure sufficient color density, the illustrations are first photographed with a plate making camera, printed on photographic printing paper, pasted on a mount, And had Then, a plate making film was prepared from under the plate, and a printing plate was further prepared.

In recent years, with the development and spread of computers,
Both manuscripts and illustrations have been produced by digital processing, and in response to this, major printing shops have also digitized the plate making process, and systems for directly making plate making films using an imagesetter have become widespread. Along with this, since the demand for the conventional photographic paper for plate making has decreased, the production of the photographic paper has been partially stopped, making it difficult to obtain the photographic paper.

[0004]

However, due to the problem of initial investment in introducing a digital system, many small and medium-sized printing shops still continue to use the conventional plate making system.
Due to the problem of supply of stencil printing paper at such establishments, there is an increasing demand for an inexpensive, high-quality stencil printing system that can use a conventional stencil printing system instead of stencil printing paper.

Accordingly, the present invention provides an underlay production method using a photographic paper for plate making as an alternative to a conventional system, and a printed matter having a good absorbency of ink used, a high color density and a clear image is obtained. The purpose is to provide a recording sheet for a composition.

[0006]

According to the present invention, there is provided a recorded material obtained by recording printing information on a recording sheet having a porous layer containing a pigment and a binder on a base material using an ink jet printing apparatus. The present invention provides a composition printing method characterized in that a composition is prepared by using the above, and the composition recording sheet.

In order to increase the color density of a print, the higher the transparency of the ink receiving layer, the better. The haze value, which is an index of the transparency of the porous layer, is preferably 20% or less.
More preferably, it is 0% or less. Here, the haze value of the porous layer refers to the haze value of the transparent film itself of the substrate based on a value obtained by forming a porous layer having a thickness of 20 μm on a transparent polyethylene terephthalate (hereinafter referred to as PET) film and measuring with a haze meter. The value obtained by subtracting the haze value.

[0008] The color density of a printed matter recorded on the underlay recording sheet of the present invention by the ink jet recording method is as follows.
It is preferably three or more. If the ratio is less than 1.3, a clear printed matter cannot be obtained when a printing plate is prepared from a plate, which is not preferable.

The underlay recording sheet of the present invention is prepared, for example, as it is or as it is by cutting out and attaching it to a backing sheet to prepare a underlaying sheet. Therefore, if the glossiness of the recording sheet is high and the image of the printed matter recorded on the recording sheet is good, the light source for photographing is easily reflected and the image of the film for plate making may be unclear, which is not preferable. . For example, the 60-degree specular glossiness specified in JISZ8741 is preferably 10% or less, more preferably 5% or less.

As the pigment in the present invention, an organic pigment,
Any inorganic pigment can be used. As the inorganic pigment, various inorganic compounds such as silica and alumina can be used, but alumina hydrate, particularly alumina hydrate crystal having a boehmite structure (composition formula: AlOOH)
XH ₂ O: 0 <x ≦ 2), that is, pseudo-boehmite is preferable, and its colloidal aggregate is particularly preferable. In the recording sheet, it is more preferable that the boehmite crystal is oriented with the b-axis perpendicular to the sheet surface, because high absorbency and transparency are imparted.

When the porous layer contains pseudo-boehmite, its pore structure is preferably composed of pores having a radius of substantially 1 to 30 nm. Furthermore, the pore volume is 0.3-2.0c
The case of c / g is preferable because it has sufficient absorbency and the transparency of the porous layer is high. More preferably 0.4 to
1.5 cc / g. In order to obtain a porous layer having such a pore structure, for example, it is preferable that a mixed solution of pseudo-boehmite sol and a binder is applied as a coating liquid on a substrate and dried. The measurement of the pore size distribution in the present specification is based on the nitrogen adsorption / desorption method.

Means for providing a porous layer on a substrate is, for example, a method in which a binder is added to pseudo boehmite sol to form a slurry, and the substrate is formed using a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater, or the like. A method of coating on top and drying can be adopted.

As the binder in the present invention, an organic binder is preferably used. Examples thereof include starch and denatured products thereof, polyvinyl alcohol (hereinafter referred to as PVA).
And modified products thereof, styrene-butadiene copolymer rubber (SBR) latex, acrylonitrile-butadiene copolymer rubber (NBR) latex, carboxymethylcellulose, hydroxymethylcellulose, polyvinylpyrrolidone, and the like.

The amount of the binder used is preferably about 3 to 50% by weight of the pigment contained in the coating solution.
When the amount of the binder used is less than 3% by weight, the strength of the porous layer may be insufficient, and when the amount is more than 50% by weight, the ink absorbability may be impaired. Absent.

A plurality of pigments can be used in the porous layer for the purpose of improving ink absorbency and controlling surface gloss. For example, when pseudo-boehmite is used, silica gel, alumina gel and the like are preferably used in combination.
In addition, various additives such as a cationic resin, an antioxidant, and a fluorescent whitening agent can be added to improve the fixing property and light resistance of the dye and control the color of the recording sheet.

In the present invention, the substrate is not particularly limited, and various substrates can be used. Specifically, various plastic sheets such as pulp-based paper, synthetic paper, and polyester-based resins such as PET and polyester diacetate, polycarbonate-based resins, and fluorine-based resins such as ethylene-tetrafluoroethylene copolymer. Any of these can be preferably used. It is preferable to use paper in consideration of the ease of handling when attaching to a mount or the like in order to produce a composition. Further, for the purpose of improving the adhesive strength between the base material and the porous layer, the base material may be subjected to a corona discharge treatment, an undercoat or the like before forming the porous layer.

In the present invention, when the porous layer is formed from a layer containing pseudo-boehmite and a binder, it is preferable to provide a silica gel layer on the porous layer because the scratch resistance of the surface is improved. The silica gel layer is preferably a coating layer obtained by adding a binder to silica sol and applying the same. As silica sol, the average particle diameter is 10 to 90 nm
And a solid content of 1 to 20% by weight is preferred because the effect of improving scratch resistance is high.

As the binder to be added to the silica sol, the same binder as that used for forming the porous layer can be used, but it is particularly preferable to use a silicon-containing polymer. The amount of the binder used is determined by the solid content (SiO 2
₂ conversion) is preferably 1 to 30% by weight. When the amount of the binder used is less than 1% by weight, the mechanical strength of the silica gel layer is insufficient, and the protective effect of the pseudo-boehmite layer may be insufficient. If the amount of the binder used exceeds 30% by weight, the ink absorbency is insufficient, and beading or the like may occur.

The silica gel layer can be formed by applying the above coating solution on the porous layer of pseudo-boehmite and drying. The thickness of this silica gel layer is 0.1-30μ
m is preferable. When the thickness of the silica gel layer is less than 0.1 μm, the protective effect of the pseudo-boehmite porous layer is not sufficiently exhibited, and the scratch resistance may be insufficient. If the thickness of the silica gel layer exceeds 30 μm, the transparency of the coating layer is impaired, which is not preferable.
More preferably, it is 0.2 to 2 μm.

In the present invention, the printing of a plate on the recording sheet obtained as described above uses an ink jet printing apparatus in order to obtain a clear image having a high color density. It is preferable to use an ink containing a dye as the coloring material. As a solvent for the ink, both a solvent containing water as a main solvent and an oily solvent can be suitably used. Then, the recorded matter printed on the recording sheet is used as a manuscript, for example, an operation such as pasting it on a mount is performed to obtain a copy.

[0021]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples (Examples 1, 2, and 3) and Comparative Examples (Example 4), but the present invention is not limited thereto.

Example 1 Pseudo-boehmite sol and PV obtained by hydrolyzing and peptizing aluminum isopropoxide
A (degree of saponification 99.8%, degree of polymerization 2000) was mixed at a solid content weight ratio of 100: 12 to prepare a coating liquid having a solid content concentration of 15% by weight. This coating liquid was applied to a high-quality paper having a basis weight of 100 g / m ² using a bar coater so that the coating thickness after drying became 20 μm, and dried to form a pseudo-boehmite layer. The pore structure of the pseudo-boehmite layer had a radius of substantially 1 to 30 nm, and the pore volume was 0.8 cc / g.

Further, on this pseudo-boehmite layer, a silica sol having a primary particle diameter of 20 to 30 nm and a silicon-containing polymer (trade name: R-Polymer, R-113, manufactured by Kuraray Co., Ltd.)
0) (R-1130 / SiO)
₂ = 0.1) Silica sol coating liquid after drying has a thickness of 1μ
m and dried, and then heat-treated at 140 ° C to obtain a recording sheet. The 60 ° specular gloss of this recording sheet was 11%.

The above coating solution is coated with 100 μm thick transparent PE
T was applied using a bar coater such that the coating thickness after drying became 20 μm, and the haze value was measured with a haze meter to be 5%.

Example 2 Same as Example 1 except that spherical silica gel (manufactured by Asahi Glass Co., Ltd., trade name: Sunsphere H31) was added to a coating solution comprising pseudo-boehmite and PVA in an amount of 5% by weight based on pseudo-boehmite. To produce a recording sheet. The 60-degree specular gloss of this recording sheet was 4%. The haze value of the porous layer measured in the same manner as in Example 1 was 1
9%.

Example 3 A recording sheet was obtained in the same manner as in Example 2 except that the amount of spherical silica gel added was 30% by weight based on pseudo-boehmite. The 60-degree specular gloss of this recording sheet was 3%. The haze value of the porous layer measured in the same manner as in Example 1 was 40%.

Example 4 A high-quality paper having a basis weight of 100 g / m ² used as a base material of a recording sheet in Example 1 was used as a recording sheet without any coating. The 60 degree specular gloss was 4%.

[Evaluation] A black solid pattern was printed on the recording sheets of Examples 1 to 4 using a commercially available inkjet printer (trade name: PM-700C, manufactured by Seiko Epson Corporation), and a commercially available color densitometer (Macbeth Corporation) was used. ) Was measured. In addition, the text was printed with a character having a size of 5 points, and the sharpness was evaluated in four stages (◎, △, Δ, ×, ◎ was the sharpest, and × was the most unclear). Table 1 shows the results.

[0029]

[Table 1]

[0030]

According to the present invention, by using a recording sheet in which a specific material is used for an ink receiving layer and printing a plate by an ink jet recording method, a high color formed by a collection of minute perfect circle dots is obtained. A clear image with high density can be formed. The image thus obtained is of high quality comparable to an image printed on photographic paper, and has the advantage of being inexpensive to produce.

Claims (8)

[Claims] 1. Printing information is recorded on a recording sheet having a porous layer containing a pigment and a binder on a base material by using an ink-jet printing apparatus, and an underprint is produced by using the obtained recorded matter. A method for producing a composition, comprising: 2. The method according to claim 1, wherein the haze value of the porous layer is 20% or less. 3. The method according to claim 1, wherein the pigment contains pseudo-boehmite and the thickness of the porous layer is 5 to 100 μm. 4. The pore structure of a porous layer containing pseudo-boehmite and a binder is substantially composed of pores having a radius of 1 to 30 nm, and has a pore volume of 0.3 to 2.0 cc / g. The method according to claim 3. 5. The porous layer is obtained by applying and drying a coating liquid containing a pseudo-boehmite sol and a binder.
The underlaying method described. 6. The method according to claim 3, wherein a silica gel layer is provided on a porous layer containing pseudo-boehmite and a binder. 7. The method according to claim 1, wherein the color density of the recorded matter printed on the recording sheet is 1.3 or more. 8. An underprinting recording sheet having a porous layer containing a pigment and a binder on a substrate for carrying out the underprinting method according to any one of claims 1 to 7.