JPS63175084A - Semisolid ink - Google Patents

Abstract

PURPOSE:To obtain a hot-melt semisolid ink, capable of forming a clear image even on an impermeable surface of bad wettability, readily erasable after recording and useful for recording devices, e.g. various notice boards, etc., by containing a resin containing coumarone, indene or a copolymer thereof. CONSTITUTION:A semisolid ink, obtained by containing a resin containing coumarone, indene or a copolymer thereof, e.g. expressed by the formula (l is 0-20; m is 0-25; n is 0-28; l and m are not 0 at the same time) and having 300-2,500 average molecular weight, as an essential component, capable of well recording even on white boards or electronic blackboard sheets and readily erasable after recording since films are excellent, have strong cohesive force and exhibit effective releasability. The above-mentioned semisolid ink 3 is used in, e.g. a recording head 1 consisting of a housing 2, heating element 4 having an ink passage hole 5, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a semi-solid ink suitable for application to recording devices such as image processors, electronic typewriters, facsimiles, and various bulletin boards, and a recording method using the same. It is something.

[Conventional technology]

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 thermal head heats the ink film to Recording is performed by melting ink and attaching it to a recording medium. However, in the thermal transfer recording method using the above-mentioned ink film, not only is the device configuration complicated, such as the need to install an ink film feeding mechanism in the recording device to which the method is applied, but also the ink film must be disposable. Therefore, running costs are high, and furthermore, processing of the ink film used is complicated.

In order to improve the above-mentioned drawbacks, a filmless thermal transfer recording method that does not use an ink film has been proposed, for example, as disclosed in Japanese Patent Laid-Open Nos. 59-118493 and 59-225990, and has attracted attention. are collecting. In this method, basically, instead of holding ink on an ink film, semi-solid ink is held in a recording head that has ink passage holes, the ink is melted by heating and flows out through the passage holes, and it is transferred to paper, etc. Transfer recording is performed by adhering it to a recording medium.

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

As shown in the figure, a recording head 1 holds semi-solid ink 3. Here, 2 is a housing, and 4 is a heating element for heating and melting the semi-solid ink. The heating element 4 has an ink passage hole 5 through which the heated and melted ink 3a flows out. 9 is a recording paper as a recording medium, and IO
is a platen roller for conveying the recording paper 9. Note that a pressure 11 is applied to the semi-solid ink 3 as desired for the purpose of facilitating outflow and replenishment of the ink 3.

In the above configuration, when heat is generated in the heating element 4, the semi-solid ink 3 in the vicinity of the heating element melts and softens to reduce its viscosity, and this molten ink 3a flows out from the ink passage hole 5. The ink passage holes 5 are provided in each of the heating elements 4 of the recording head 1 formed in an array.
By selectively applying a heat generation signal to the recording paper 9, a desired recorded image such as a character or an image is formed on the recording paper 9. During this recording, depending on the physical properties of the semi-solid ink, the semi-solid ink may not be supplied smoothly immediately after the ink is melted and transferred, resulting in a temporary ink shortage near the heating element. For example, by applying pressure 11 to the ink as illustrated in FIG.
This makes it easy to immediately replenish 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.

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. have.

Another example of a recording head applied to such a filmless thermal transfer recording method is
There is one proposed as -74293.

That is, a housing capable of accommodating ink, a heating element provided in the housing and selectively generating heat according to an image signal, a plurality of ink passing holes passing through the heating element, and a plurality of ink passage holes provided on the heating element. This is a recording head having an ink reservoir divided into a plurality of parts.

If this recording head is in direct contact with the ink passage hole and the recording paper as shown in Figure 11 above, it will slide in that state, which may cause trailing or fogging in the recorded image. This is an attempt to improve image quality by solving these problems.

FIG. 2 is a schematic cross-sectional view of an example of a recording device including the recording head, and FIG. 3 is an external view of a multi-type recording head in which the recording portions of the head are arrayed in a line.

In the figure, reference numeral 1 denotes a recording head, which houses heat-melting semi-solid ink 3 which becomes semi-solid at room temperature and maintains high viscosity at room temperature, but whose viscosity decreases at high temperatures. It has become.

A heating element is provided in a part of the housing 2,
A plurality of these heating elements are arranged in an array as shown in FIG. 3, and each heating element 4 is provided with a desired number of ink passage holes 5 (four in this example).

Further, electrodes 6 that can be energized according to image signals are connected to each of the heating elements 4, and by selectively applying a voltage to the electrodes 6, the heating elements 4 individually generate heat. It is composed of

Furthermore, a frame-shaped window 7 is provided on the heating element 4, as shown in FIG.

In printing using the recording head 1, as shown in FIG. 2, the window 7 is brought into contact with a recording paper 9, which is a recording medium, and the recording paper 9 is conveyed by a platen roller lO rotating in the direction of arrow a. Do it while doing it.

Details of such recording will be explained using FIG. 4.

First, when a voltage is applied to the heating element 4 through the electrode 6, the heating element 4 generates heat, and the semi-solid ink 3 near the heating element 4 is heated. Since this ink has a high viscosity at room temperature, it does not pass through the ink passage hole 5, but when heated as described above, the viscosity decreases and it passes through the ink passage hole 5.

As described above, the ink 3 that has passed through the ink passage hole 5 spreads into the ink reservoir 8, and returns to a semi-solid state or a state close to it due to heat dissipation at that time. At this time, housing 2
It is preferable to apply a static pressure higher than the external pressure inside the tube because it promotes passage of the ink 3.

Next, when a voltage is applied to the heating element 4 according to the image signal, the heating element 4 selectively generates heat (the state shown in FIG. The recording paper 9 is separated from the ink reservoir 8 and is transported in the direction of the arrow.
(state shown in FIG. 4(B)). Further, when the ink reservoir 8 is emptied by the transfer, the ink 3 in the housing 2 whose viscosity has been reduced by the heat generated by the heating element 4 passes through the ink passage hole 5 and is replenished into the ink reservoir 8 (see FIG. 4).
C), and becomes semi-solid due to heat dissipation during spreading into the ink reservoir 8 as described above (FIG. 4 CD).

By repeating the above steps in accordance with the image signal, recording dots corresponding to the size within the ink reservoir 8 are continuously formed on the recording paper 9, and an ink image is transferred.

[Problem that the invention seeks to solve]

By the way, in such a filmless thermal transfer recording method, when the recording medium is, for example, a whiteboard or electronic blackboard sheet having a surface made of a material with relatively poor wettability, such as a fluororesin or a silicone resin, image formation is necessary. It is desirable that the formed image not only be able to be erased easily, but also be easily erased by lightly rubbing it with a dry cloth, paper, blackboard eraser, or the like.

However, conventionally known thermal transfer inks, printing inks, or inks for ballpoint pens and fountain pens do not satisfy these requirements, and do not have good erasability because they cause trailing when erasing after recording. was not obtained.

Furthermore, the viscosity of marker ink for whiteboards is so low that it passes through the passage holes even at room temperature, causing fogging and staining.

The present invention has been made in view of the above points, and its main object is to provide a heat-melting semi-solid ink that can satisfy both recordability and erasability.

[Means for solving problems]

To achieve the above object, the present invention provides a recording medium comprising a housing capable of containing ink, a heating element provided in the housing and generating heat in accordance with an image signal, and an ink passage hole penetrating the heating element. This is a heat-melting semi-solid ink that is applied to devices and is characterized by containing as an essential component a resin containing coumaron, indesi, or a copolymer thereof.

[For production]

The semi-solid ink of the present invention records well not only on plain paper, but also on whiteboards, electronic blackboard sheets, etc., which have surfaces with relatively poor wettability made of fluororesin, silicone resin, etc., and after recording. is the known blackboard eraser paper,
It can be easily erased by rubbing with a cloth or the like. This is because the resin containing coumaron, indesi, or their copolymers used in the present invention has superior film properties compared to other resins or waxes, and has strong cohesive force, so it exhibits effective mold release properties. It is.

The semi-solid ink of the present invention contains a resin containing coumaron, indesi, or a copolymer thereof as an essential component, and is prepared by appropriately combining a solvent for softening the resin, a coloring agent, a dispersing agent, etc. as necessary. Ru. Preferably, the viscosity and melt viscosity at room temperature may be adjusted by appropriately adjusting the blending ratio.

Preferred resins containing coumaron, indesi, or their copolymers used in the present invention are made from solvent naphtha contained in light oil in coke oven gas, and are mixed with BF3, H2SO4, A1[1;1
It is a thermoplastic resin obtained by copolymerizing heavy apricot or copolymer using a catalyst such as No. 3 or the like.

Specifically, the following formula (where l is an integer of 0 to 20, m is an integer of 0 to 25, n
is an integer from 0 to 28, and ! and m do not become 0 at the same time. ) with an average molecular i of 300 to 2,500. Commercially available products include Nippon Steel Kumaron G-90 and T-120 manufactured by Nippon Steel Chemical Co., Ltd.

Solvents used with the above resins include kerosene, liquid paraffin, benzene, toluene, xylene, solvent naphtha, mineral spirit, butyl alcohol,
Polyhydric alcohols such as benzyl alcohol, glycerin, ethyl acetate, diethyl ether, dioxane, furfural, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, carbon tetrachloride, chloroform, methyl cellosolve, ethyl cellosolve, phenyl cellosolve, diethylene glycol, monomethyl ether, etc. Examples include organic solvents such as derivatives thereof, and oils such as mineral oils and animal and vegetable oils.

As the colorant, dyes and pigments commonly used in technical fields such as printing can be used.

Specifically, for example, carbon black, iron oxide powder, nigrosine dye, lamp black, Sudan black SM, alkali blue, fast yellow G, benzine yellow, pigment yellow, India first orange, irgazine red, varanitroaniline.・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, and Pigment Blue, Prilliant. Green B, Phthalocyanine Green, Oil Yellow G, Zapon Fast Yellow CGG, Kaya Set Y
963, Kayaset YG, Sumiblast Yellow GG
, Zapon First Orange RR, Oreil Scarlet, Sumiplast Orange G, Orazole Brown B, Pomelo First Scarlet CG, Eisenspiron Red BEH.

Conventionally known dyes and pigments such as Oil Pink OP, Victoria Blue F4R, First Gen Blue 5007, Sudan Blue, and Oil Peacock Blue 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 401 Ji%.

Here, semi-solid refers to a state that maintains solidity to the extent that it does not flow out from the ink passage holes at room temperature, and as long as it maintains such solidity, even semi-solid
Paste-like or highly viscous inks can be used as semi-solid inks.

In the method for producing the semi-solid ink of the present invention, a resin containing coumaron or indesi or a copolymer thereof as described above is heated at 70 to 350°C, preferably at 100 to 200°C.
It is preferable to heat and melt it at a temperature of about 50° C., and then mix the above-mentioned solvent, coloring agent, etc. thereto as appropriate. At this time, kneading is performed using a dispersing machine such as a roll mill, sand grinder, ball mill, or attritor to check the compatibility and dispersibility of the solvent, colorant, etc. in the resin containing the coumaron or indesi or their copolymers. It would be good to try to improve.

Recording using the semi-solid ink of the present invention can be performed using a recording apparatus having an ink passage hole as described above. In addition, the recorded images recorded in this way are not only made of paper but also other materials such as fluororesin (Teflon), silicone resin, polyethylene terephthalate, polyethylene, polypropylene, etc., which have an impermeable and relatively poorly wettable surface. Even when recording is made on a whiteboard, electronic blackboard sheet, etc., it can be easily erased by rubbing it with a known blackboard eraser, cloth, etc.

Of course, recording using the semi-solid ink of the present invention is not limited to using a fixed type recording head as described above, but for example, a rotating type recording head as shown in Fig. 5 below can be used. It goes without saying that the number of ink passage holes is not particularly limited to four as shown in the third figure, but may be any desired number.

The recording head 1 shown in FIG. A window 7 is provided on the body 4 and the ink 'aI8
By configuring this, it is possible to rotate in the circumferential direction (Fig. 5 (8)). The heating element 4 also has a signal electrode 6a and a ground electrode 6b as shown in FIG. 5(B).
are connected to each other, and a brush 6c is connected to each electrode 6a, 6b.
, 6d are configured to be in contact with each other.

Therefore, when a voltage pulse corresponding to the image signal is applied to each of the brushes 6c and 6d, the heating element 4 on the line in contact with the ground brush 6d selectively generates heat, thereby transferring the semi-solid ink. .

The recording head 1 is in contact with the recording paper and is rotatable as the recording paper is conveyed, so that ink trailing, fogging, etc. can be efficiently prevented.

〔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 Image recording was performed using the recording head shown in FIGS. 2 and 3 under the conditions and method shown below.

First, a carbon resistor was used as the heating element 4 provided in the housing 2. This heating element 4 is 1 as shown in FIG.
They were arranged in an array with one pitch, and each heating element 4 was provided with four ink passage holes 5 each having a diameter of 0.2 mrn.

Furthermore, an electrode 6 made of aluminum was connected to each of the heating elements 4, and a frame-shaped window 7 made of a glass material was further provided on the heating element 4. This window 7 has a thickness of 0.05 mm and is placed on the heating element 4 by 0.8 mm.
The ink reservoir 8 was constructed in a frame shape in which ink reservoirs 8 of 8 mm in diameter were formed in an array. 24 V x to this electrode 6
Recording was performed while applying a voltage impulse of 20+ ns and a static pressure of 0.1 atm gauge pressure inside the housing 2 to promote passage of the semi-solid ink 3 through the holes.

Semi-solid ink 3 was prepared as follows using Coumaron resin shown in Formulation 1 below.

12 Monme 1 Yu 1) Kumaron resin (manufactured by Nippon Steel Chemical Co., Ltd., Nippon Steel Kumaron G-
90, softening point 93°C) 68% by weight 2) Xylene -29.5% by weight 3) Dye (Oil Blue IIN, manufactured by Orient Kagaku Kogyo Co., Ltd.)
-2.5% by weight, that is, the coumaron resin of the above formulation 1 was heated and melted at about 150°C, dye and xylene were added in this order, and each was sufficiently stirred and mixed to prepare a semi-solid ink.

Using this semi-solid ink, the recording medium 9 is of two types: plain paper and tetrafluoroethylene sheet (manufactured by Asahi Glass Co., Ltd., Afflex), and images are formed using the above-mentioned recording head for each of the two types of recording medium. The recording characteristics were evaluated. Furthermore, among the images formed on the recording medium, the erasability of the images on the tetrafluoroethylene sheet was evaluated using a whiteboard eraser.

The results are shown in Table 1.

As is clear from Table 1, the semi-solid ink of the present invention was excellent in both recording and erasing properties.

Example 2 The recording properties and erasability of this ink were evaluated in the same manner as in Example 1, except that a semisolid ink having the following formulation 2 was used. The results are shown in Table 1.

-／＞66E Butt Sl) Kumaron resin (manufactured by Nippon Steel Chemical Co., Ltd., Nippon Steel Kumaron T-
120, softening point 119°C)...55% by weight2
) Benzyl alcohol...20% by weight Ethyl acetate -22% by weight 3) Dye (manufactured by Orient Chemical Industry Co., Ltd., Oil Black HBB)
...3% by weight Example 3 The recording properties and erasability of this ink were evaluated in the same manner as in Example 1 except that a semi-solid ink having the following formulation 3 was used. The results are shown in Table 1.

1) Kumaron resin (manufactured by Nippon Steel Chemical Co., Ltd., Nippon Steel Kumaron G-
75, softening point 78℃)...75% by weight2)
Dimethyl ether -22% by weight3) Dye (
Orient Chemical Industry Co., Ltd., Oil Blue II N)
-3% by weight Comparative Example 1 The recording properties and erasability of this ink were evaluated in the same manner as in Example 1 except that a semisolid ink having the following formulation 4 was used. The results are shown in Table 1.

L) Ethylene vinyl acetate (manufactured by Hirodyne Industries, Ltd.)
Hyrodyne 4500, softening point 70°C)...50% by weight -2) Methyl isobutyl ketone -20% by weight Methyl ethyl ketone...25% by weight3) Dye (
Nigrosine BASE EX manufactured by Orient Chemical Industry Co., Ltd.
) -5 weight ff 1% comparative example 2 Using the wax, paraffin and dye shown in the following formulation 5, after weighing and mixing the predetermined amounts of these, 1.5
The mixture was added to a monotube sand mill kept at 140° C. together with mmφ glass beads, and dispersed and mixed for 30 minutes at 2,000 revolutions to separate the beads, and then cooled to prepare a semi-solid ink.

LZL 亙方1 1) Oxidized wax (manufactured by Nippon Seirosha, NSP 6115,
Melting point 77°C)...30% by weight2) Isoparaffin (manufactured by Nippon Petrochemical Co., Ltd., Mekata Isosol 300)...46% by weight
3) Dye (manufactured by West German Bayer AG, Ceres Orange (CER)
ES Orange) R) -4% by weight Same as Example 1 except using this semi-solid ink,
The recording characteristics and erasability of this ink were evaluated. The results are shown in Table 1.

Table 1 [Evaluation Criteria] Image quality: O: Good △: Fairly good ×: Poor erasability; O: Completely erased by scratching △: Slightly poor but erasable ×: Unerasable As is clear from the above examples and comparative examples Furthermore, the semi-solid ink of the present invention not only exhibits good recording properties even on recording media having surfaces that are impermeable and have relatively poor stain resistance, but also has excellent erasability.

〔Effect of the invention〕

As explained above, according to the semi-solid ink of the present invention, even if the recording medium has an impermeable surface with relatively poor wettability, such as those used for whiteboards, electronic blackboards, etc. Not only can a clear image be easily formed, but also it can be easily erased by rubbing with a blackboard eraser or the like after writing.

Furthermore, in the present invention, since the semi-solid ink inside the housing flows out from the ink passage hole to perform recording on the recording medium, it is possible to form clear images economically without using an ink film as in the past. It is something.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an example of a recording head used in a filmless transfer recording method, FIG. 2 is a schematic sectional view of another example of a recording head used in a filmless transfer recording method, and FIG. Fig. 4 is an explanatory diagram of the printing process using the printing head of Fig. 2; Fig. 5 (8) and (B) FIG. 2 is an explanatory diagram of a rotary recording head.

Claims (1)

[Claims] (1) A housing that can accommodate ink, and a heating element that is provided in the housing and generates heat in response to an image signal;
A heat-melting property which is applied to a recording device having an ink passage hole penetrating the heating element and is characterized by containing a resin containing coumaron, indesi, or a copolymer thereof as an essential component. semi-solid ink.