JPS6366272A - semi-solid ink - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semi-solid ink, particularly for use in recording devices to which a filmless thermal transfer recording method is applied, such as image processors, electronic typewriters, facsimile machines, and various bulletin boards. It relates to semi-solid inks.

(Prior art) Currently, thermal transfer recording methods generally use an ink film, and the ink film is usually interposed between a recording medium such as paper and a thermal head, and the ink film is heated by the thermal head. The ink in the heated area is melted and attached to the recording medium to perform recording.However, in the thermal transfer recording method using the above ink film, an ink film feeding mechanism is installed in the recording device applied to the method. Not only does this complicate the device configuration, as the ink film must be disposed of, but the running cost is high because the ink film must be disposable, and furthermore, the processing of the used ink film is complicated.

For example, in JP-A-59-++a493, there is a solution to improve the shortcomings such as ``-!''. i-Gate, 59-225
A filmless thermal transfer recording method that does not use an ink film, as disclosed in Japanese Patent No. 990, has been proposed and is attracting attention. Basically, instead of holding ink in an ink film, semi-solid ink is held in a recording head having passage holes, the ink is heated and melted, and flows out through the passage holes, and is used for recording on paper, etc. It is attached to a medium and performs translocation ζ' writing.

FIG. 1 shows an example of a recording head used in such a filmless thermal transfer recording method.

As shown, the recording head 6 holds semi-solid ink 2. Here, 3 is an ink container, and 1 is a heating element for heating and melting the semi-solid ink. The heating element 1 has a passage hole 7 through which the heated and melted ink 2a flows out. 4 is a recording paper as a recording medium, and 5 is a platen roller for conveying the recording paper 4. Note that a pressure 8 is applied to the semi-solid ink 2 as desired for the purpose of facilitating outflow and replenishment of the ink 2. Further, as the heating element 1, a carbon sheet, ruthenium oxide, or the like is usually used.

In the above configuration, when heat is generated in the heating element 1, the semi-solid ink 2 near the heating element melts and softens, reducing its viscosity, and this molten ink 2a flows out from the passage hole 7.

The passage holes 7 are provided in the heating elements 1 of the recording head 6 formed in an array, and by selectively applying a heating signal to each heating element 1, characters, images, etc. can be printed on the recording paper 4. A desired recorded image is formed. During this recording, depending on the physical properties of the semi-solid ink, the supply of semi-solid ink may not be carried out smoothly immediately after melting and transferring the ink, resulting in a temporary ink shortage near the heating element, but generally speaking For example, as illustrated in FIG. 1, immediate replenishment of ink is facilitated by applying a pressure 8 to the ink. Therefore, it is common to use a semi-solid ink that not only melts when heated, but also does not flow out from the passage hole before heating, and has sufficient fluidity to facilitate ink replenishment. It is. The heating temperature during recording is usually 40 to 12
It is said to be around 0℃.

Filmless thermal transfer recording methods that use such semi-solid inks have the advantage of not consuming ink film compared to normal thermal transfer recording methods, and are more energy efficient because the ink is heated directly without using a film. has.

However, in order to perform stable recording in such a filmless thermal transfer recording method, the semi-solid ink must be melted immediately after heating and transferred onto the recording medium, and the transferred ink must immediately solidify to form a recorded image. In addition to forming a recording image, it is desirable that a recorded image formed by being firmly adhered to a recording medium during transfer does not easily peel off. however,
Conventional semi-solid inks do not necessarily adhere well to recording media, and the recorded image after transfer may peel off due to scratches, etc., resulting in chips in the formed image or making the image unclear. .

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to solve the drawbacks and problems of the above-mentioned conventional examples, and in particular to provide a method for firmly adhering onto recording media. An object of the present invention is to provide a semi-solid ink for use in a filmless thermal transfer recording method capable of performing clear and high-quality recording with high sensitivity without causing defects in formed images.

[Means for solving problems]

The above objects of the present invention are achieved by the present invention as follows.

A semi-solid ink used in a filmless thermal transfer recording method in which semi-solid ink is melted by heating and flows out from a passage hole, and the flowed out semi-solid ink is transferred and recorded on a recording medium,
A semi-solid ink, characterized in that the semi-solid ink contains an edylene-vinyl acetate copolymer resin.

[Effect]

In the present invention, the ethylene-vinyl acetate copolymer resin is preferably contained in the semi-solid ink in an amount of 10 to 80% by weight, more preferably 30 to 60% by weight.

The semi-solid ink of the present invention containing the above-mentioned ethylene-vinyl acetate copolymer resin has improved adhesion to the recording medium, and it firmly adheres to the recording medium not only during transfer but also after transfer, resulting in defects in the formed image. It is possible to perform clear and high-quality recording with high sensitivity without causing any problems.

The ethylene-vinyl acetate copolymer resin used in the semi-solid ink of the present invention can be obtained by copolymerizing polyethylene and vinyl acetate under pressure using a peroxide or an azo compound as a catalyst as shown in the following formula. The ratio of vinyl acetate to ethylene is 20% by weight.
45% by weight is preferably used.

CH7=CH,, + Cl-12=CH (however, n represents an integer of 6 or more and 10,000 or less, m is 10 or more -
represents an integer less than or equal to 30,000. ) Specifically, such ethylene-vinyl acetate copolymer resins are commercially available, such as EVAFLEX 21O (manufactured by Mitsui Polychemical Co., Ltd.), Sumitate H-20 (manufactured by Sumitomo Chemical Co., Ltd.), and TOREAX DI. -1 (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.).

These ethylene-vinyl acetate copolymer resins can be used alone or in combination of two or more.

The semi-solid ink of the present invention is prepared by appropriately combining the above-mentioned ethylene-vinyl acetate copolymer resin with a heat-melting binder, a softener, a coloring agent, or other additives.

The thermofusible binder used in the semi-solid ink of the present invention is
The melting point or softening point is preferably 130°C or lower, more preferably 40 to 120°C, and the melt viscosity at 130°C is preferably 4 to 200 cps.

If the melting point or softening point of the heat-melting binder is less than 40°C, it will be difficult to maintain a semi-solid state in a high-temperature environment, and the ink will melt and flow out from the passage hole before being heated by the heating element. Sometimes it happens. On the other hand, if the melting point or softening point exceeds 130° C., the amount of heat supplied to melt the semi-solid ink becomes excessive, which may cause damage to the heating element.

Further, if the melt viscosity at 130° C. is less than 4 cps, the viscosity of the semi-solid ink in a heated and molten state is too low, and the amount of ink flowing out from the passage hole becomes excessive, which may make recording difficult. On the other hand, if the melt viscosity at 130°C exceeds 200 cps, the viscosity in the heated and molten state will be too high, and the ink will not be able to pass through the passage hole of the heating element, making it difficult to transfer it to the recording medium smoothly. There is.

Specific examples of such heat-melting binders include natural waxes such as wood wax, spermaceti wax, beeswax, lanolin, carnauba wax, candelilla wax, montan wax, and ceresin wax, paraffin wax, and microcrystalline wax. petroleum wax,
oxidized petrolatum, oxidized wax, ester wax,
Low molecular weight polyethylene, synthetic waxes such as Fischer-Tropsch wax, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, higher alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of sucrose, and fatty acid esters of sorbitan. esters such as oleylamide, amides such as oleylamide, polyamide resins, polyester resins, epoxy resins, polyurethane resins, cellulose resins, polyvinyl alcohol resins, petroleum resins, phenolic resins, polystyrene resins, natural Examples include rubber, elastomers such as styrene-butadiene rubber, isoprene rubber, and chloroprene rubber, rice wax, osikelite, and hydrogenated castor oil. These can be used alone or in combination of two or more.

Among the above heat-melting binders, particularly preferable ones include the following.

In other words, natural waxes such as beeswax, wood wax, and lanolin, and paraffin wax with a molecular weight of about 300 to 500 (
Commercially available products include Nippon Seirosha Co., Ltd.) INP-] (melting point 64.
8℃), HNP-3 (melting point 64.2℃), paraffin wax manufactured by Noda Wax Co., Ltd.), molecular weight 400-700
Microcrystalline wax (commercially available products include Nippon Seirosha's former MIC1oao (melting point 84°C)
ICl070 (melting point: 80°C), oxidized wax (commercially available products include NPS 6010 (melting point: 75°C) manufactured by Hiki Seiro Co., Ltd.
), etc.), ester wax (commercially available products include NPS 6] 15 (melting point 77°C) manufactured by Hiki Sabaro Co., Ltd.), oxidized vetrolatum wax (commercially available products include HAD manufactured by Hiki Seiro Co., Ltd.)
5080 (softening point 76℃), IAD 5090
(softening point: 77° C.), fatty acid amides (commercially available products include Aramide O manufactured by Lion Akzo (melting point: 68° C.), etc.).

Examples of softeners for these binders include paraffinic hydrocarbons, naphthenic hydrocarbons, halogenated hydrocarbons, ethers, acetals, ketones, and derivatives thereof, which are liquid at room temperature. In addition to these softeners, various nitrogen compounds, solvents such as phenol, D
OP (dioctyl phthalate), DBP (dibutyl phthalate), DIDP (diisodecyl phthalate)
, DTDP (ditridecyl phthalate), Dll
P (cyheptyl phthalate), DNP (dinonylphthalate), sialfol 610 phthalate, BBP
(butyl benzyl phthalate), BPBG (butylphthalyl butyl glycolate), DOA (dioctyl adipate), DOZ (dioctyl azelate),
Semi-solid ink can be created by appropriately selecting plasticizers such as 0OS (dioctyl sebacate), epoxidized fatty acid esters, chlorinated fatty acid esters, TCP (tricresyl phosphate), or oil agents such as mineral oil, vegetable oil, or animal oil. The melting point or soft F point, melt viscosity, viscosity at room temperature, etc. may be adjusted as appropriate.

Examples of colorants include carbon black, iron oxide powder,
Nigrosine dye, lamp black, Sudan black SM, alkali blue, first yellow G, benzine yellow, pigment yellow, India first orange, irgazine red, balanitroaniline red, toluidine red, carmine FB, permanent Bordeaux FRR, Pigment Orange R, Lysol Red 20, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Prilliant Green B, Phthalocyanine Green, Oil Yellow GG, Zapon. First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Zapon First Orange RR, Oreil ° Scarlet, Sumiplast Orange G, Orazole Brown B, Pomelo First Scarlet CG, Eisenspiron Red BEH, Oil Pink OP , Victoria Blue F4R, First Gen Blue 5007, Sudan Blue, Oil Peacock Blue, and other conventionally known dyes and pigments can be used without particular limitation.

These colorants can be used alone or in combination of two or more, and are preferably contained in the ink in an amount of 1 to 40% by weight.

The method for producing the semi-solid ink of the present invention is not particularly limited. For example, the method for producing the semi-solid ink of the present invention is
After heating and melting at ~250°C, preferably 100~200°C, and adding the above-mentioned ethylene-vinyl acetate copolymer resin and softeners, colorants, additives, etc. as appropriate, thoroughly mixed and dispersed, and left standing or It is preferable to cool the mixture to room temperature while stirring.

Although not specifically explained in Section 1-1, the present invention relates to a semi-solid ink for a rotary recording head used in a filmless transfer recording method previously proposed by the applicant in Japanese Patent Application No. 16747. It is also suitable as

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained using Examples, but these are not intended to limit the present invention in any way.

Example 1 Beeswax (manufactured by Noda Wax Co., Ltd., bleached beeswax, melting point 60°C
) 30 parts by weight was heated and melted at 140°C, and liquid paraffin (Matsuzai Oil Co., Ltd., Moresco White P-7) was added to this.
0) 60 parts by weight, 5 parts by weight of Irgazin Ret, and 15 parts by weight of Edylene-vinyl acetate copolymer resin (manufactured by Mitsui Polychemical Co., Ltd., Evaflex 210),
The mixture was added to a monotube sand mill kept at 140° C. together with glass beads of 5 mm diameter, and dispersed and mixed at 2000 revolutions per minute for 30 minutes. The beads were then separated and cooled to prepare a semi-solid ink.

The recording characteristics of this ink were evaluated by performing transfer recording on recording paper using the recording head illustrated in FIG. Recording was performed by using a carbon sheet as the heating element of the recording head, and applying a potential pulse of 5 to 30 V to an electrode connected to the carbon sheet to generate Joule heat in the heating element to heat and melt the ink in the vicinity. When recording,
0.1 to 2.0 kg/crn' in the direction of the ink passage hole
The pressure was applied constantly or in synchronization with the potential pulse. When recording was performed in this manner, recording dots were recorded in response to potential pulses with high sensitivity. The recorded image thus formed was firmly adhered to the recording paper, and was clear and of high quality without chipping or density unevenness.

Example 2 Ester wax (manufactured by Nippon Tanuro Co., Ltd., NPS 6115,
melting point 77°C) 30 parts by weight, isoparaffin (manufactured by Nippon Petrochemical Co., Ltd., Isosol 300) 60 parts by weight, Irgasin Ret 5 parts by weight, and ethylene-vinyl acetate copolymer resin (manufactured by Sumitomo Chemical Co., Ltd., Sumitate HA-20) 1
A semi-solid ink was obtained in the same manner as in Example 1 except that 0 parts by weight was used.

The recording properties of this ink were evaluated in the same manner as in Example 1, and as in Example 1, it was clear and of high quality without chipping or density unevenness.

Example 3 30 parts by weight of polyamide resin (manufactured by Sanso Kagaku Co., Ltd., HT-W-60, melting point 70°C), polybutene (manufactured by Nippon Petrochemical Co., Ltd.,
LV-50) 60 parts by weight, Phthalocyanine Blue 5
A semi-solid ink was obtained in the same manner as in Example 1, except that 7 parts by weight of ethylene-vinyl acetate copolymer resin (Soleax DH, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.) were used.

The recording properties of this ink were evaluated in the same manner as in Example 1, and as in Example 1, it was clear and of high quality without chipping or density unevenness.

Comparative Example A semi-solid ink was obtained in the same manner as in Examples 1 to 3 except that the ethylene-vinyl acetate copolymer resin was not contained.

When the recording properties of these inks were evaluated in the same manner as in Example 1, the adhesion to the recording paper was weak in all cases.
It was not possible to obtain a clear recorded image due to chipping and density unevenness in the formed image.

As is clear from the above Examples and Comparative Examples, the semisolid ink of the present invention had excellent recording properties.

〔Effect of the invention〕

As explained above, according to the semi-solid ink of the present invention,
It is transferred with high sensitivity by heat and firmly adheres to the recording medium, so that clear and high-quality recording can be performed with high sensitivity without causing chipping or density unevenness.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of a recording head used in a filmless thermal transfer recording method.

Claims (1)

[Claims] (1) A semi-solid ink used in a filmless thermal transfer recording method in which semi-solid ink is melted by heating and flows out from a passage hole, and the semi-solid ink that flows out is transferred and recorded on a recording medium, the semi-solid ink is made of ethylene. - A semi-solid ink characterized by containing a vinyl acetate copolymer resin.