JP3172300B2 - Plain paper transfer type pressure-sensitive copying paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plain paper transfer type pressure-sensitive copying paper for transferring color characters onto plain paper. Further, the present invention relates to a plain paper transfer type pressure-sensitive copying paper for optical reading which can optically read a color image such as a character, a numeral, a bar code and the like.

[0002]

2. Description of the Related Art An electron-donating, almost colorless dye precursor (hereinafter referred to as a color former) and an electron-accepting acidic substance (hereinafter, referred to as a color former).
It has been known for a long time that a colored image can be obtained by a contact reaction with a developer. As a specific use of this phenomenon, for example, pressure-sensitive copying paper (US Pat.
505470 and 2505489) and heat-sensitive recording paper (JP-B-45-14039).

In general, as a developer for pressure-sensitive copying paper, activated clay, acid clay, attapulgite, zeolite, bentonite, silica, inorganic solid acids such as aluminum silicate and the like, novolak type phenol resins and salicylic acid derivatives, Uses a polyvalent metal salt of a salicylic acid derivative. In particular, a polyvalent metal salt of a salicylic acid derivative has good coloring properties and is widely used in the market. In recent years, many salicylic acid resins or polyvalent resins thereof have been developed for the purpose of improving the color development speed of conventional phenolic resin-based developers and the poor water resistance of colored characters of salicylic acid-based developers. Metal salts have been proposed as developers. These developers include salicylic acid and α, α'-dialkoxy-p
-Polyvalent metal salts of co-condensation resins such as xylene
No. 176875, No. 62-178387, No. 62-1
No. 78388, No. 63-53092, No. 63-159
Nos. 082 and 63-160877), a polyvalent metal salt of a resin obtained by reacting a styrene derivative with a salicylic acid derivative having an aromatic substituent (JP-A-63-1867).
No. 29), a polyvalent metal salt of a resin obtained by reacting a salicylic acid derivative having an aromatic substituent with a benzyl halide (JP-A-63-254124), and others.
Organic developers such as resin polyvalent metal salts described in JP-A-63-289017 are known. Also, salicylic acids,
Rosins and polyvalent metal salt compounds composed of polyvalent metal compounds have also been disclosed as organic color developers (JP-A-2-56).
No. 3).

In general, as a pressure-sensitive copying paper, an upper sheet having a color former layer containing microcapsules containing a color former on a support, and a developer layer containing a color developer on the support. The lower paper, if necessary, a separate type in which a developer and a color former are used in combination with a middle paper provided on the front and back of the support, or the developer and the color former in the form of a single layer or a multilayer The self-type provided on the same surface is used. As a special case, there is also known a plain paper transfer type pressure-sensitive copying paper in which a developer and a color former are contained in the same coating layer, and the resulting color is transferred to plain paper to be colored. Such examples are disclosed in JP-B-63-7160 and JP-B-63-33476.
And JP-A-63-33478 and JP-B-3-13994.

In recent years, the use of pressure-sensitive copying paper by passing it through a machine and causing the machine to read a colored character or mark has been increasing, and examples of such a usage of pressure-sensitive copying paper have been increasing. Are disclosed in JP-A-2-188291 and JP-A-2-231.
No. 190, No. 4-173288, No. 4-212882
Nos. 4,224,991; 4,251,785; 4,272,889; and the like. Typical reading devices include optical reading devices such as OCR, OMR, and label bar codes.

As described above, when a color image of a pressure-sensitive copying paper is read by a machine, if the frictional resistance of the surface of the pressure-sensitive copying paper is large, double feeding occurs at the time of paper feeding by the machine, and a reading error occurs. Or paper jams in the machine, which could cause trouble. In particular, under high humidity conditions, double feeding tends to occur. This is mainly because a pressure-sensitive copying paper provided with a developer layer containing a color developer and a self-coating layer containing a color developer and a color developer is passed through a machine.
It has been desired to develop a pressure-sensitive copying paper for optical reading which can obtain a copied image without providing these coating layers.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an optical reading pressure-sensitive copying paper for reading a color image such as a character, a numeral, a bar code, etc., in which a trouble such as a double feed or a paper jam occurs even when the paper passes through a reading machine. It is an object of the present invention to provide a pressure-sensitive copying paper having good optical readability and good paper passing property.

[0008]

Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventors have found that a microcapsule (A) containing an electron-accepting organic color developer and the electron-accepting organic microscopic agent. Plain paper transfer type provided on a support with a coating layer containing a colorless or light-colored microcapsule (B) containing an electron-donating colorant which reacts with a colorant and produces a color image having absorption at 600 to 1000 nm. It has been found that the above object is achieved by using pressure-sensitive copying paper.

To obtain a plain paper transfer type pressure-sensitive coloring paper for optical reading, an electron-donating coloring agent is used so that the color image transferred to the plain paper has a large absorption intensity with respect to the wavelength of the light source of the reader. It is necessary. The light source wavelength of the optical reading device is generally in a wavelength range of 600 to 1000 nm. The optical reading density is represented by the value (PCS value) / (reflectance of non-colored portion on the surface coated with the color developer-reflectance of color-developed portion) / reflectance of non-colored portion in the light source wavelength range.
The S value is preferably 0.55 or more, and particularly preferably 0.7 or more.

A specific example of such an electron-donating color former suitable for optical reading is disclosed in JP-B-49-17489.
No. 58-5940, No. 58-27825, No. 6
3-51113, JP-B-4-4316, 4-50
No. 64, No. 4-5065, No. 4-5066, No. 4-
No. 5068, JP-A-51-90608 and 55-11
No. 5448, No. 62-85886, No. 62-2436
No. 52, No. 63-9572, No. 63-37158,
63-62777, 63-102975, 6
No. 3-120760, No. 63-130667, No. 63
154389, 63-159384, 63-
No. 189281, No. 63-270672, No. 63-2
No. 95672, No. 64-29371, No. 64-422
No. 76, JP-A-1-210378 and JP-A-1-236627
9, No. 1-138280, 2-138368,
2-251484, 3-71883, and 3-1
No. 14878 can be used, but the present invention is not limited thereto.

In addition, these can be used in combination with a conventionally known general pressure-sensitive dye (electron-donating color-forming agent) for pressure-sensitive copying paper. A color former suitable for optical reading and a commonly used pressure-sensitive dye are microencapsulated by a generally known method. Also, microencapsulation of the developer can be performed by a generally known method.

Examples of the ordinary microencapsulation method include a coacervation method, a monomer polymerization method, an interfacial polymerization method, an in situ polymerization method, and the like. Preferred examples are shown in US Pat. No. 4,001,140. Urea-formaldehyde resin capsules or melamine-formaldehyde resin capsules disclosed in JP-A-53-84881 and JP-A-54-49984.

As the color developer used in the present invention, among the color developers described above, an organic color developer which is dissolved in the solvent of the internal phase of the capsule and can be microencapsulated relatively easily is used. Examples of the organic developer include substituted phenol / formaldehyde resins described in JP-B-42-20114, salicylic acid derivative polyvalent metal salts described in JP-B-51-25174, and 2,2 described in JP-A-55-113591. 2
Zinc salt of '-bisphenolsulfone compound, Tokuho 4
The compound polyvalent metal salt of a carboxylated terpene phenol resin and an aromatic monocarboxylic acid described in JP-A-28235 is exemplified, and a novolak-type phenol resin is particularly preferred.

As the non-volatile solvent used for the internal phase of the microcapsules, those used in general pressure-sensitive copying paper can be used. For example, alkylated diphenylmethane,
Alkylated diphenylethane, alkylated diphenylpropane, diarylalkane such as alkylated diphenylbutane, alkylnaphthalene, alkylated naphthalene such as dialkylnaphthalene, alkylated biphenyl, aromatic ester type, fatty acid ester type, chlorinated paraffin,
Examples thereof include paraffin oils such as n-paraffin and isoparaffin, and these can be used alone or as a mixture of two or more.

The dissolution concentration of the color former in the internal phase of the microcapsules is preferably 2 to 20% by weight, particularly preferably 3 to 12%. Further, the dissolution concentration of the color developer is preferably from 10 to 60% by weight, particularly preferably from 30 to 50% by weight. UV absorber as an additive in the internal phase of the microcapsule,
Antioxidants, light stabilizers, waxes, odor neutralizers and the like can be added.

The volume average particle diameter of the microcapsules is 3
-15 microns is preferred, and 5-10 microns is particularly preferred. The usage ratio of the microcapsules containing the color former and the microcapsules containing the developer can be used in the range of 10-90: 90-10, but is preferably in the range of 15-50: 85-50.

The microcapsules include a stilt agent such as wheat starch, corn starch, and fine cellulose powder, an adhesive such as a water-soluble adhesive and a latex, and, if necessary, a surfactant, a wax, a desensitizer, and a desensitizer. A foaming agent, an ultraviolet absorber, a white pigment, and the like are added, and the whole or partial coating is applied to a support such as acidic paper, neutral paper, synthetic paper, or film. In the case of partial application, the microcapsules containing the color former and the microcapsules containing the developer are used in the form of an ink corresponding to a printing method such as flexo, gravure, screen, letterpress, planographic printing and the like.

Examples of the waxes include animal waxes such as beeswax, whale wax and lanolin; vegetable waxes such as candelilla wax, carnauba wax and rice wax; mineral waxes such as montan wax and ozokerite; paraffin wax; Petroleum waxes such as microcrystalline wax, synthetic waxes such as low molecular weight polyethylene and its derivatives, saturated fatty acid amide-based waxes, unsaturated fatty acid-based amide waxes and the like can be used alone or in combination. It is preferably about 30% by weight or less based on the total amount of the microcapsules containing the developer.

As the surfactant, any of anionic, cationic, nonionic and amphoteric surfactants can be used, and it is preferable to use about 15% by weight or less based on the total solid content of the coating solution.

[0020]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.
In addition, the part in an example shows a weight part and shall show a dry weight part unless there is a notice.

Example 1 [Preparation of microcapsules enclosing a color former] 3,3-bis (4'-diethylamino-2-ethoxyphenyl) -4
12 parts of azaphthalide was heated and dissolved in 88 parts of a diarylethane-based solvent (Hisol SAS N-296: Nippon Petrochemical) to obtain 100 parts of an internal phase oil. This is styrene-
It was added to 100 parts of a 5% aqueous solution of maleic anhydride copolymer under vigorous stirring to obtain an emulsion having a volume average particle size of 5 microns.
Separately, 7 parts of melamine, 37% formaldehyde aqueous solution 18
And an aqueous solution of a melamine-formaldehyde initial condensate obtained by heating and dissolving the mixture on an alkaline side, and adding the resulting mixture to the emulsion and stirring at a temperature of 75 ° C. for 3 hours. Microcapsules were obtained.

[Preparation of Microcapsules Enclosing Developer] P
40 parts of PP resin (para-phenylphenol-formaldehyde resin, manufactured by Sumitomo Duy Reds) was heated and dissolved in 60 parts of a diarylethane-based solvent (Hisol SAS N-296) to obtain 100 parts of an internal phase oil. This was microencapsulated in the same manner as in Example 1 to obtain a developer-containing microcapsule having an average particle size of 7 μm.

[Preparation of plain paper transfer type pressure-sensitive copying paper] 30 parts of microcapsules containing color developing agent 70 parts of microcapsules containing developing agent 40 parts of wheat starch 20 parts of paraffin wax emulsion 35 parts of styrene-butadiene latex 35 parts or more are mixed. Thus, a plain paper transfer type pressure-sensitive copying paper coating liquid having a solid content of 30% was obtained. This coating solution was applied to high-quality paper of 40 g / m ² by an air knife coating method so that the dry coating amount was 7 g / m ² , to obtain a plain paper transfer type pressure-sensitive copying paper of a full-surface coating type. .

Example 2 [Preparation of plain paper transfer type pressure-sensitive copying paper] 20 parts of microcapsules containing color former of Example 1 80 parts of microcapsules containing developer of Example 1 40 parts of wheat starch 40 parts of dioctyl phosphate monoatanol Amine salt 50 parts Modified vinyl acetate derivative (Corponyl: manufactured by Nippon Gohsei) 50 parts Methyl alcohol 150 parts The above materials were mixed to obtain a flexographic ink. This ink was applied to a high quality paper with a basis weight of 50 g / m ² using a form printer.
Printing was performed so that the ink volume was 5 g / m ² , to obtain a partially coated plain paper transfer type pressure-sensitive copying paper.

Comparative Example 1 15 parts of the color former used in Example 1 was replaced with 3,3-bis (P-
Except for using 15 parts of (dimethylaminophenyl) -6-dimethylaminophthalide, a microcapsule enclosing a color former was prepared in the same manner as in Example 1, and then transferred to plain paper of the full-surface coating type in the same manner as in Example 1. A pressure-sensitive copy paper was obtained.

Comparative Example 2 A partial application type plain paper transfer type pressure-sensitive copying paper was obtained in the same manner as in Example 2 except that the microcapsules containing the color former of Comparative Example 1 were used.

The microcapsule coating layer side of the plain paper transfer type pressure-sensitive copying paper obtained in Examples 1 and 2 and Comparative Examples 1 and ² was superimposed on a high-quality paper having a basis weight of 60 g / m ^{2, and} a bar was printed with a dot printer. The code was printed. As Comparative Example 3, a commercially available carbonless pressure-sensitive copying paper (N-
40 blue) and commercially available carbonless pressure-sensitive copying paper (N-
60) and a barcode was printed by a dot printer. Each barcode copied paper 100
Under high humidity conditions of room temperature 30 ° C and relative humidity 85%,
Bar code reader with light source wavelength of 660 nm (NB-1
00: manufactured by Japan ADM Co., Ltd.) to measure the double feed rate. Further, the bar code readability is evaluated as ○ (×:
The results are shown in Table 1 in two-stage display of good readability and x: poor readability.

[0028]

[Table 1]

[0029]

As is evident from the results in Table 1, the plain paper transfer type pressure-sensitive copying paper according to the present invention has excellent optical readability, has no double feed when passing through a machine, and has an optical readability. It can be seen that the paper is excellent as pressure copying paper.

Continuation of the front page (56) References JP-A-60-168690 (JP, A) JP-A-57-203588 (JP, A) JP-A-57-191085 (JP, A) JP-A-2-188291 (JP) JP-A-4-187483 (JP, A) JP-A-2-286389 (JP, A) JP-A-58-191771 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) B41M 5/124

Claims (2)

(57) [Claims] 1. A microcapsule (A) containing an electron-accepting organic developer and a colorless or pale-colored electron which reacts with the electron-accepting organic developer to produce a color image having an absorption at 600 to 1000 nm. Plain paper transfer type pressure-sensitive copying paper, characterized in that a coating layer containing a microcapsule (B) containing a donor color former is provided on a support and can be transferred to plain paper. 2. The plain paper transfer impression according to claim 1, wherein the coating layer containing the microcapsules (A) and (B) is partially applied on a support. Press paper.