JP3253259B2 - Postcard paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing apparatus, a home printing machine, a thermal transfer word processor, and the like, which improves the ink absorption and the drying property in order to impart a suitable property to the ink. An object of the present invention is to provide a postcard that reduces the number of rings, tailings, and the like, and also provides flexibility to the postcard and facilitates paper feeding of the printer.

[0002]

2. Description of the Related Art Conventionally, pens and brushes have mainly been used to draw letters, designs, etc. on postcards shown in FIG. Had been given suitability. However recently,
Ink jet printing devices, home simple printing machines (printing pretend), and word processors have become widespread as means for printing postcards, and when these devices are applied, the conventional postcard 1 shown in FIG. Problems such as trouble in automatic paper feeding due to the hardness of the paper have come to occur.
Further, poor ink absorbency (3 indicates absorbed ink) causes tailing 4 due to rubbing as shown in FIG.

[0003] As shown in the figure, since the conventional postcard is composed of a single layer structure, it is difficult to satisfy such ink absorption and paper feeding (flexibility). Dedicated postcards are commercially available for each method, but the general user may not be fully aware of the printing method, and there is a problem of causing puzzles at stores and trouble after purchase.

[0004]

SUMMARY OF THE INVENTION The present invention is to provide a multi-type postcard which simultaneously solves the ink absorption and paper feedability (flexibility) of postcards which are required at present.
In other words, the ink absorption is improved to improve the drying property, and the print quality (bleeding, tailing prevention effect, etc.) is obtained while providing flexibility, thereby providing suitability for prints, ink jet printing devices, and home simple printing machines. , Word processor (printer)
Paper feed suitability, and at the same time, keep the offset print suitability.

[0005]

Generally, the speed of ink absorption depends on the size of the pores of the paper and the contact angle between the pulp and the ink forming the pores. In order to improve the absorption of the ink, the size of the paper may be reduced by making the surface of the paper porous, but on the other hand, the absorption in the surface direction of the ink, so-called bleeding, occurs, and the print quality deteriorates.

Conversely, if the size of the paper is increased by making the surface of the paper denser, the absorbability of the ink is reduced, and the ink is trailed to lower the print quality. In addition, since the phenomenon of bleeding is the absorption and spreading of the ink in the surface direction, the tailing and the bleeding phenomenon can be prevented by adopting a structure that strongly absorbs the ink absorption in the thickness direction. .

[0007] The present invention, from such a viewpoint, FIG.
As shown in the figure, the postcard 11 has a multi-layer structure, and an ink absorbing layer is provided as a back lower layer 11b of the printing / painting layer (back layer 11a) to enhance the ink absorption in the thickness direction and to reduce the ink absorption in the surface direction. The structure minimizes absorption and diffusion.

That is, as shown in FIGS. 1 and 2, the back lower layer 11b of the back layer 11a is used as an ink absorbing layer,
a. High-viscosity, oil-based inks, such as pretend prints, and low-viscosity, water-based inks, such as ink-jets, by rapidly absorbing the ink 12 that has slipped through
2 to improve absorption.

Further, in order to improve the bleeding-preventing action of a low-viscosity, water-based ink such as an ink jet, the back surface layer 11a has a large specific surface area as compared with kaolin or talc used as a filler while giving size to the back layer 11a itself. White carbon (hereinafter abbreviated as WC) is blended to enhance the absorption effect.

It is desirable that the WC be blended in an amount of 5 to 10% by weight. In other words, below this range, the absorption of the aqueous ink is poor, and above this range, the sizing property is reduced, bleeding is generated, and inter-fiber bonding is inhibited, so that the surface strength is reduced.

Further, a sizing agent is added to the back surface layer 11a in order to suppress the absorption and diffusion of the ink in the surface direction, so that the contact angle of water with respect to the surface of the back surface layer 11a is 85 ° to 110 °. The size and type of the sizing agent are adjusted so as to fall within this range. If the contact angle is smaller than this range, the absorption is good, but bleeding occurs and the print quality deteriorates. If the contact angle is larger than this range, the ink absorption decreases and drying becomes poor. The contact angle is used as a parameter indicating the size of the surface of the back layer 11a, because the size of the surface has a very high correlation with the print quality and ink absorption.

The basis weight of the back layer 11a is 20 to 40 g /
m ² is desirable, and when it is less than this, the bleeding of the lower back layer 11b is seen through and the print quality is inferior.
1b arrives late and absorption is poor.

The back lower layer 11b is a layer for rapidly absorbing the ink 12 that has escaped from the back layer 11a. Wood fiber pulp is originally provided with an excellent absorbing power, so that no or little sizing agent is added. Alone can be an absorbing layer. As shown in FIG. 3, the ink 12 adhered to the surface of the backside layer 11a
Is rapidly absorbed by the lower back layer 11b, and as shown in FIG. In FIG. 3, reference numeral 13 denotes the absorbed ink.

On the other hand, it is known that postcards made from pulp having a low density have a large thickness and thus low flexibility. The flexibility of this postcard is closely tied to modern word processing and printer paper feeds. In other words, the rolls used for paper feed in word processors and printers are small in size, and they are small in diameter and can be bent at sharp angles during paper feed. Make it difficult and cause misprints.

As a parameter for measuring the flexibility, there is a "stiffness test", which is known to be proportional to the cube of the thickness. It is effective to increase the density of postcards.

According to the present invention, as a result of intensive studies, it was found that the density of a sheet prepared according to JIS P8209 was 0.6 g / layer when the "freeness" measured according to JIS P8121 was 500 ml. By using wood pulp (LBKP as a suitable example) which is more than cm ³ ,
I found it to be a flexible postcard. Therefore, in the case of a four-layer structure, the lower back layer 11 other than the back layer 11a of the postcard is used.
b, LBKP produced from a high-density aspen material is suitable for the lower surface layer 11c and the surface layer 11d.

The lower surface layer 11c is a base layer, and characteristics required for a postcard other than ink absorption and flexibility can be freely adjusted by this layer. For example, in order to improve the paper strength of the postcard, it is possible to strengthen the beating and fine-tune the basis weight and thickness. This layer can be arbitrarily blended, especially when it is desired to blend waste paper in connection with recent forest protection.

The surface layer 11d is a layer mainly for forming a surface for writing a name and the like. The surface of this layer may be used for printing charges, stamp designs, postal code frames, etc. on a high-speed offset printing machine. In many cases, it is important that the suitability is sufficiently satisfied. For example, the reproducibility of a stamp pattern, the register of a stamp pattern, the transferability of ink, the drying property of ink, the discoloration of paper, the hue, and the like are given. Since the conventional postcard has been sufficiently studied in that respect, the surface layer (offset printing layer) 11d of the postcard of the present invention is used.
Was also designed to maintain the suitability as before.

Usually, starch or polyvinyl alcohol (hereinafter abbreviated as PVA) is often applied to paper by a size press or the like in order to improve surface strength from printability, and PVA is also applied to postcards. This PVA is an excellent coating agent for improving the surface strength.
Although a high value of 0 or more is used, the absorption of the ink is deteriorated due to the film property.

In the present invention, in order to improve the surface strength without impairing the ink absorption, the problem was solved by applying PVA having an average degree of polymerization of 700 to 1500 to both the surface of the back surface layer 11a and the surface of the surface layer 11d. In addition, PVA having a degree of polymerization lower than this range has insufficient surface strength, and PVA having a degree of polymerization higher than this range has a problem that the pores on the surface of the paper are blocked and the absorption of ink is rapidly reduced because the film has a strong film property. .

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Tables 2, 4, 6, 8 and
Table 10 shows Examples 1 to 7 and Comparative Examples 1 to 19 of the present invention, and Tables 3, 5, 5, and 11 show the postcard suitability test results, respectively, and Tables 2 and 4 The pulp A to F used in Examples and Comparative Examples in Tables 6, 8 and 10 are prepared as follows.

1. Pulp Preparation In order to investigate the ink absorbency and flexibility of the pulp, the following types of pulp were selected and prepared.

Pulp A: LBKP produced from eucalyptus wood produced in Australia, using PFI, JIS P81
It was beaten and prepared until the freeness measured according to No. 21 reached 500 ml.

Pulp B: LBKP produced from Australian eucalyptus timber using PFI and JIS P81
It was beaten and prepared until the freeness measured according to No. 21 reached 450 ml.

Pulp C: LBKP prepared from Japanese oak, beech, hippopotamus and the like produced in Honshu was prepared in the same manner as Pulp A.

Pulp D: LBKP produced from Japanese domestic oak, beech, birch and the like was prepared in the same manner as pulp A.

Pulp E: LBKP prepared from North American aspen was prepared in the same manner as Pulp A.

Pulp F: LBKP prepared from eucalyptus wood from Australia and NBKP prepared from spruce wood from North America were blended at a ratio of 1: 1 and prepared similarly to pulp A.

The pulp prepared above was subjected to JIS P820
Table 1 shows the density of the sheet prepared according to No. 9 with a basis weight of 60 g / m ² .

[0030]

[Table 1]

2. Method for Producing a Postcard Sheet The method for producing a postcard in each of the above Examples and Comparative Examples is as follows.

Using the pulp shown in Table 1, a sheet made of paper having the layer constitution shown in Table 2 was superposed on a TAPPI standard square sheet machine in a wet paper state before being coated. Then press dewatering and 105
Dry at 5 ° C for 5 minutes. The basis weight of each layer is 30 g / m ^{2 for} the back layer and the lower back layer, 90 g / m ^{2 for the} lower surface layer, and 40 g / m ^{2 for} the upper layer.
m ² to give a total basis weight of 190 g / m ² . Thereafter, PVA was applied by a test size press and processed by a calender to obtain a sample.

3. Postcard aptitude test The postcard aptitude test of the postcard in each of the above Examples and Comparative Examples is performed by the following method.

1. Aqueous ink suitability A; pen writing size, bleeding test 1, 2, 3, 4 and 5 from Nizym 1 to 5 which is not completely bleeding according to TAPPI paper pulp test method NO12
Was visually evaluated in five steps. 3 or more is regarded as good.

B: Inkjet printer, bleeding and drying test Printer model: canon BJ-10V (ink:
BC01), and Nijimi is an image analysis device LUZEX.
-F binarizes the "B" character and measures the area to 3.0
mm ² or less was not completely bleeding. Immediately after printing, the paper was rubbed with a load of 40 g / cm ^{2 with} a silk-bon paper, and the time without tailing was indicated in seconds.

C: Measurement of contact angle Measurement device: FIBRO 1100 DAT (Dynamic
Absorption Tester The liquid used is distilled water, and the measurement is made immediately after dropping (1 second).

2. Home printing, drying test Print model: Print Pretend PG-10 (manufactured by Riso Kagaku Co., Ltd.) After printing solid with HM ink black, 5 minutes and 30 minutes later, PPC paper is transferred onto the print surface and transferred to PPC. The density of the ink transferred to the paper was measured by Macbeth density RD-918 to determine the colorimetric density (relative density with respect to the blank portion of the sample). 5
A concentration of 0.15 after 30 minutes and a concentration of 0.04 or less after 30 minutes were regarded as good drying properties.

3. Flexibility (stiffness) test The test was performed according to JIS P 8125 test method.

4. Word processor Paper feed test Word processor model: Bungo Color JX5700Ac (N
20 (made by EC Co.), color printing was performed after setting 20 sheets in a postcard cassette, and the state of automatic paper feeding was observed. This model has an automatic paper feed correction function to retry when a postcard is not smoothly sent.

○ → 20 sheets could be printed smoothly without any trouble. △ → Clogging sometimes, it took time, but 20 sheets could be automatically printed. × → Paper jam frequently occurred, and 20 sheets could not be automatically printed.

5. Suitability for offset printing The surface strength was measured according to JIS P 8129, and 8 or more was regarded as good.

Examples 1 to 7 of the present invention and Comparative Examples 1 to 1
9 is as shown in Tables 2, 4, 6, 8, and 10, and the results of the suitability tests are as shown in Tables 3, 5, 7, and 11.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

[0048]

[Table 7]

[0049]

[Table 8]

[0050]

[Table 9]

[0051]

[Table 10]

[0052]

[Table 11]

Table 2 shows a postcard manufacturing method for investigating the influence of the pulp density of the back layer (printing / painting layer) 11a.
Pulp types A, B, C, D, E, and F used the pulp prepared in Table 1.

Table 3 shows the results of a postcard suitability test conducted on the postcard prepared by the method shown in Table 2. The density and type of the pulp on the back layer affect the ink drying property of home-use simple printing.

Table 4 shows a postcard manufacturing method for investigating the influence of the size of the back lower layer (ink absorbing layer) 11b on the back layer 11a. The sizing agent is expressed by EM-505 (Harima Chemical Co., Ltd.) in terms of pulp addition ratio. did.

Table 5 shows the results of the postcard suitability test conducted on the postcards prepared by the method shown in Table 4. The contact angle changes depending on the size of the back surface layer 11a, which affects the pen writing size and the drying property of the ink for ink jet. Is given. The size of the back lower layer 11b strongly affects the drying property of the inkjet ink.

Table 6 shows the lower back layer 11b and the lower front layer (base layer) 11
c) A postcard manufacturing method for investigating the influence of the density of the pulp on the surface layer (offset printing layer) 11d. Pulp types A, B, C, D, E and F used the pulp prepared in Table 1.

Table 7 shows the results of performing a postcard suitability test on the postcards prepared by the method of Table 6. The pulp densities of the lower back layer 11b, the front lower layer 11c, and the surface layer 11d are closely related to the paper stiffness. That has influenced the word processing paper feed test.

Table 8 shows a postcard manufacturing method for investigating the effect of filler type and filler addition rate (WC) on the backside layer 11a. Kaolin and talc commonly used in papermaking are used as filler types. The WC used had an average particle diameter of 7 microns. The rate of addition was expressed as pulp addition rate.

Table 9 shows the results of performing a postcard suitability test on the postcards prepared by the method shown in Table 8. The type of filler has a strong influence mainly on the drying properties of the ink-jet ink.
The addition rate of C affects pen writing size, ink bleeding and drying property, and offset printing suitability.

Table 10 shows a postcard manufacturing method for investigating the influence of the degree of polymerization of PVA applied to both surfaces of the back surface layer 11a and the surface layer 11d. The application method is a size press machine for testing (manufactured by Kumagaya Riki). It was used. The coating amount was adjusted to the target amount by the PVA concentration, and the total amount (g / m ² ) of both surfaces was indicated.

Table 11 shows the results of a postcard suitability test conducted on postcards prepared by the method shown in Table 10. The degree of polymerization of PVA was determined in terms of pen writing size, ink jet drying property, drying property of home-use simple printing, and offset printing suitability. Have an effect.

[0063]

[Effects of the Invention] Recently, when drawing letters and designs on postcards, the method of drawing is not only pen and brush, but also prints, thermal transfer method of word processor, ink jet method, electrophotography method, simple home print (pretend play), offset. Diversification, such as printing. As a result, in the past, it was necessary to select a postcard suitable for the method of drawing, and to purchase a special postcard if the quality was desired. In this case, the seller or the purchaser may not be fully aware of the difference between the methods, and a problem may occur during use.

According to the present invention, the ink that has slipped out of the back layer is rapidly absorbed by the lower back layer, and high-viscosity and oil-based inks such as prints and low-viscosity and water-based inks such as ink jets can be favorably absorbed.

The postcard has a multi-layer structure, and the offset printing layer (surface layer), base layer (top and bottom layers), and ink absorbing layer (back bottom layer) are measured for freeness as measured in accordance with JIS P8121.
Is 500 ml, the density of a sheet produced according to JIS P8209 is 0.6 g / cm ³ or more. By using wood fiber pulp, good flexibility is given to the postcard, and the paper is fed to a word processor or a printer. Improved.

Thus, a postcard that can be obtained with only one type of postcard can be provided, which has been achieved only with the special postcard of each printing method, and the purchase and transaction of the postcard becomes smoother. Problems at the store and during use have been reduced, and the standardization of standards has made it possible to reduce the cost of manufacturing postcards.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a layer structure of a postcard showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the postcard.

FIG. 3 is an enlarged cross-sectional view illustrating an ink absorbing effect of the postcard.

FIG. 4 is a plan view illustrating an ink absorption state in FIG. 3;

FIG. 5 is an enlarged cross-sectional view illustrating the ink absorbing function of a conventional postcard.

FIG. 6 is a plan view illustrating an ink trailing state in FIG. 5;

[Explanation of symbols]

 11 Postcard 11a Back layer (printing / painting layer) 11b Lower back layer (ink absorbing layer) 11c Lower surface layer (base layer) 11d Surface layer (offset printing layer) 12 Ink 13 Absorbed ink

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keisuke Ota 798 Hina, Fuji-shi, Shizuoka Prefecture Daishowa Paper Co., Ltd. (72) Inventor Park Pina 798 Hina, Fuji-shi, Shizuoka Prefecture Daishowa Paper Co., Ltd. (56) References JP-A-2-229070 (JP, A) JP-A-63-27251 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B42D 5/00-15/10 551

Claims (4)

(57) [Claims] 1. A postcard having an offset printing layer as a surface layer, a printing / painting layer as a backside layer, and an ink absorbing layer as a backing lower layer, wherein the printing / painting layer (backside layer) is white. Postcard paper containing carbon and a sizing agent. 2. A postcard having an offset printing layer as a surface layer, a printing / painting layer as a backside layer, and an ink absorbing layer as a backing lower layer, wherein the printing / painting layer (backside layer) is offset from the printing / painting layer (backside layer). Postcard paper, wherein polyvinyl alcohol having an average degree of polymerization of 700 to 1500 is applied to the surface of the printing layer (surface layer). 3. A postcard having an offset printing layer as a surface layer, a printing / painting layer as a back layer, and an ink absorbing layer as a lower back layer, wherein the ink absorbing layer (lower back layer) has no size. Postcard paper characterized by the following. 4. A postcard having an offset printing layer as a surface layer, a printing / painting layer as a back layer, and an ink absorbing layer as a lower back layer, wherein the offset printing layer (surface layer) and the ink absorbing layer are provided. Layer (lower back layer) is JIS P
Postcard paper characterized by using a wood fiber pulp in which the density of a sheet produced according to JIS P8209 becomes 0.6 g / cm ³ or more when the "freeness" measured according to 8121 is 500 ml. .