JP2997572B2 - Ink composition for printer ribbon and ink ribbon using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbon ink composition used for a cloth ribbon for an impact printer such as a computer and a word processor, and an ink ribbon using the same.

[0002]

2. Description of the Related Art In recent years, a so-called impact printer which prints a printing wire by driving a printing wire into an ink ribbon has been widely used as a printing device such as a computer or a word processor.

Conventionally, as a ribbon ink for impact printers, coloring materials such as dyes are used for higher fatty acids, animal and vegetable oils,
A ribbon ink which is uniformly dissolved or dispersed in an oil component such as a mineral oil is used, and such a ribbon ink is required to have a high print density and a long life.

On the other hand, in recent years, the rationalization of office work / distribution management has progressed, and the optical character reading device (OCR) or the bar code recognition device has become widespread. It is required that not only the printing density (visual density) of the area but also a sufficient density for the light of a semiconductor laser or the like in the near infrared region near 800 nm used in these readers be used. Is coming.

[0005] In response to such demands, carbon black has been conventionally used as a very useful coloring material.
The ink containing the carbon black has a drawback that the printing wire is significantly worn especially when used in a wire dot printer. Especially in the situation where the speed and quality of impact printers are called for and the dot diameter needs to be very small,
This wear has been taken up as a major problem.

As a countermeasure, dye-type inks in which an oil-soluble dye is dissolved or dispersed in an oil agent are used. However, since these dyes hardly absorb light in the near infrared region, they are used in OCR devices and the like. Is not adaptable. When a dye treated with a fatty acid such as oleic acid is used among these dye-based inks, there is a problem of wire corrosion caused by an acid group of the fatty acid, although there is a difference depending on a material of a printing wire. Was.

For example, JP-A-2-251578 proposes an oil-based ink to which a material absorbing near-infrared rays is added. However, such a material is generally expensive and the visual density is not sufficient. Therefore, its use was limited.

Japanese Patent Application Laid-Open No. 61-246083 discloses an ink ribbon using an organic pigment which causes less wear on a printing wire. However, these organic pigments also have poor absorption intensity in the near infrared. And reading by an OCR device or the like.

Furthermore, Japanese Patent Application Laid-Open No. Sho 63-170481 attempts to reduce the wear of a printing wire by using carbon black having a specific particle size or less. However, carbon black having such a small particle size has a remarkably large surface area, and its dispersion is extremely difficult. Further, even if the ink composition can be dispersed, the viscosity of the ink becomes high, and it is difficult to obtain an ink composition having excellent fluidity.

In addition, the pigment re-aggregates during storage due to instability of the dispersion, and even if carbon black as fine particles is used, the desired printing density cannot be obtained,
The agglomerated carbon black promotes the wear of the printing wire, and cannot achieve the intended effect, which is not practical.

On the other hand, various pigment dispersants have been proposed as techniques for improving the dispersibility of pigments, and some of them have been practically used in the field of ordinary printing inks and the like. For example, Japanese Patent Publication No. 54-34009 discloses a polyester oligomer obtained by dehydrating and condensing a hydroxycarboxylic acid, and British Patent No. 1,373,660 discloses a polyester oligomer obtained by amidating the above polyester oligomer with an amine compound. Have been proposed. Further, US Pat. No. 4,224,212 describes a conjugate of a polyester oligomer and a polyalkyleneimine.

However, when these conventional pigment dispersants are used as a dispersant for the carbon black having a small particle diameter, which is a colorant for an ink for a printer ribbon, the following problems are presented. For example,
In the case of the polyester oligomer or an amidated product thereof, the dispersibility of the fine carbon black is not sufficient, and a salt of the quaternized product is not only abraded,
There is a problem that the printing wire is corroded, and the dispersant described in U.S. Pat. No. 4,224,212 requires the viscosity of the dispersion because the polyalkylenimine used has a very high molecular weight. Or higher, and the desired fluidity cannot be obtained.

[0013]

SUMMARY OF THE INVENTION The present invention provides an ink for a printer ribbon, which has less wear of a printing wire of a dot printer, has sufficient visual density, and has adaptability to an OCR apparatus. What you want to do.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that carbon black of fine particles having a particle diameter smaller than the specified particle diameter is extremely effective in reducing abrasion of a printing wire. Certain facts, furthermore, the fact that a specific pigment dispersant can stably disperse the above-mentioned fine carbon black in the oil agent of the ribbon ink and prevent corrosion of the printing wire based on the acidity of the carbon black. And completed the present invention.

That is, the present invention relates to an ink composition for impact printer ribbons containing carbon black, wherein the carbon black has an average primary particle diameter of 20 mμ or less, more preferably 15 mμ or less, and is further specified below. An object of the present invention is to provide an ink composition for a printer ribbon, which comprises a reaction product obtained by reacting an amine compound with a polyester having a free carboxyl group. General formula

[0016]

General formula

[0018]

(In the general formula [I] or [II], R
₁ , R ₂ , R ₄ and R ₅ each represent an alkylene group having 2 to 4 carbon atoms, and R ₃ represents an alkyl group having 1 to 4 carbon atoms. N represents an integer of 1 to 4. The general formula [II]
In the above, when n is an integer of 2 or more, R ₄ may be an alkylene group having a different number of carbon atoms. )

Further, the present invention is to provide an ink ribbon obtained by applying the above ink composition for a printer ribbon to a ribbon cloth. Hereinafter, the ink composition for a ribbon according to the present invention will be described in more detail.
First, the carbon black used in the present invention is produced based on a furnace method and a channel method generally used conventionally. The average particle diameter of the carbon black should be 20 mμ or less, and more preferably 15 mμ or less. Have

The amount of carbon black added to the ribbon ink is 5 to 20% by weight, and if it is less than 5% by weight, sufficient OCR readability cannot be obtained. Even when black is used, the problem of wear of the printing wire becomes apparent. In order to maintain proper printing density and OCR reading density, it is preferable to use an organic pigment in combination, and various organic pigments, for example, phthalocyanine pigment, azo pigment and various lake pigments can be used. As a more preferable usage, the addition amount of the above-mentioned organic pigment which is used in combination with the improvement of the printing density while controlling the wear amount of the printing wire to a minimum while suppressing the addition amount of the carbon black within a range where the necessary OCR readability can be maintained. It is a good idea to respond. The amount of the organic pigment to be added is 5 to 35% by weight in the ribbon ink. When a dye is used in place of the organic pigment, light resistance and the like are inferior.

The reaction product specified in the present invention is obtained by reacting an amine compound represented by the following general formula [I] or [II] with a polyester having a free carboxyl group. . General formula

[0023]

General formula

[0025]

(In the general formula [I] or [II], R
₁ , R ₂ , R ₄ and R ₅ each represent an alkylene group having 2 to 4 carbon atoms, and R ₃ represents an alkyl group having 1 to 4 carbon atoms. N represents an integer of 1 to 4. The general formula [II]
In the above, when n is an integer of 2 or more, R ₄ may be an alkylene group having a different number of carbon atoms. ) ◎ Here, n needs to be an integer of 1 to 4, and when it is 5 or more, the ink viscosity becomes high, and the coating property to the ribbon cloth becomes a problem.

Specific examples of the amine compound represented by the general formula [I] include methyliminobisethylamine, ethyliminobispropylamine, ethyliminobispropylamine and the like.
Specific examples of the amino compound represented by, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine, pentapropylenehexamine, and further, dibutylenetriamine and the like Is mentioned.

As the polyester having a free carboxyl group, those having an acid value obtained by dehydration condensation of a polybasic acid and a polyhydric alcohol and having a range of 20 to 60 mgKOH / g can be used. Among them, polyester obtained by dehydration condensation of a fatty acid having a hydroxyl group is particularly preferred.

The acid value of these polyesters is 20 mg
If it is less than KOH / g, the adsorbing power to the carbon black surface becomes weak, and the desired dispersion effect cannot be obtained.
Conversely, if it exceeds 60 mgKOH / g, the length of the polyester chain becomes insufficient, and the dispersion stability becomes insufficient.

Examples of the polybasic acid which is a material for obtaining the polyester include succinic acid, adipic acid, azelaic acid, sebacic acid, 1,12-dodecanedicarboxylic acid,
1,2- or 1,4-cyclohexanedicarboxylic acid,
Terephthalic acid and the like are exemplified. As polyhydric alcohols, ethylene glycol, diethylene glycol,
Examples include propylene glycol.

Examples of the fatty acid having a hydroxyl group include ricinoleic acid, 12-hydroxystearic acid or castor oil fatty acid, and hydrogenated products thereof. And when obtaining the reaction product specified in the present invention,
It is obtained by bonding the above-mentioned amine compound and a polyester having a free carboxyl group by a conventional amidation reaction. General formula

[0032]

General formula

[0034]

[0035]

Here, the general formula [III] is a product obtained by bonding a polyester chain to the general formula [I] of an amine compound, and the general formula [IV] is a reaction product obtained by bonding a polyester chain to the general formula [II] of an amine compound. This is a simulation formula. In the above simulated formula, a polyester chain is bonded to all nitrogen atoms, but this is an ideal model, and actually varies depending on the reactivity of the amine compound or polyester, and there are also compounds having some amine value. . Here, the reaction ratio of the reactant is 0.8 to 1.0 with respect to the carboxyl group of the polyester.
It is obtained by subjecting it to a reaction at an equivalent ratio. The molecular weight of the reactant is preferably in the range of 2,000 to 17,000. The amount of the reaction product obtained by the above-mentioned reaction may be,
With respect to 0 parts by weight, a range of 5 to 50 parts by weight is preferable,
It is appropriately determined according to the particle size, surface area or surface properties of the carbon black used.

Other essential oils used in the ink for ribbons include esters of fatty acids such as sebacic acid, oleic acid and linoleic acid, castor oil, safflower oil, rapeseed oil and soybean oil. Mineral oils such as vegetable oils, spindle oils and motor oils, and nonionic surfactants can be used alone or in combination.

In the ink for a printer ribbon of the present invention, in addition to the above-mentioned essential components, it is preferable to use the above-mentioned organic pigments as needed, and any other conventionally used components can be used. Such components include coloring agents such as oil-soluble dyes, surfactants, plasticizers,
There are various binder resins.

In the method for producing the ink according to the present invention, carbon black, the reaction product, an organic pigment and other additives are added to the oil agent, and various additives conventionally used are used. And can be obtained by mixing and kneading. When an ink ribbon is prepared using the obtained ink composition, the ink ribbon can be obtained by coating a conventionally used nylon or the like with a conventionally known coating machine. .

[0040]

EXAMPLES The inks according to the present invention will be specifically described with reference to the following examples, but the present invention is not limited by these examples unless departing from the spirit and scope of the present invention.

Synthesis Example of Dispersant 12-hydroxystearic acid was dehydrated and condensed by a conventional esterification reaction to prepare a polyester having an acid value of 35 mgKOH / g. An amidation reaction was carried out on 100 parts of the polyester using 4.3 parts of methyliminobispropylamine, a compound corresponding to the compound of the formula [I] of the present invention, to obtain a reaction product A.

Similarly, 100 parts of the polyester and 2.5 parts of triethylenetetramine corresponding to the compound of the formula [II] of the present invention were similarly reacted to obtain a reaction product B.

Examples 1 to 6 and Comparative Examples 1 to 4 Ribbon inks are produced by using each material according to the recipe shown in Table 1 and using a three-roll mill. In addition, as the organic pigment, a mixture of an azo-based orange pigment, a phthalocyanine blue pigment, and a methyl violet-based lake pigment is used. As the dispersant C, a dispersant manufactured by ICI, Solsperse S-17000, and as an oil agent, , Oleic acid 2
-A mixture of ethylhexyl ester and sorbitan surfactant was used.

With respect to this ink, the fluidity, storage stability and corrosiveness to the printing wire of the ink are evaluated. On the other hand, using the obtained ink, a ribbon coated on a nylon cloth having a width of 16 mm so as to have a coating amount of 12 g / m ² was formed into a 60 m Mobius ring, which was loaded into a ribbon cassette. Using this ribbon cassette, 100 million dots are printed by an impact dot printer, and the wear of the printing wire, the printing density, and the readability by the OCR device are evaluated.

[0045]

[0046]

<Test Method> Print density: After printing ribbon ink on ordinary white continuous paper using a dot impact printer, A filter and B filter were installed using Macbeth densitometer PCM-II. Then, the print density was measured.

OCR suitability: Densitometer PCM- manufactured by Macbeth
OCR suitability was determined from the concentration measured using a B filter in II.

◎: good ○: somewhat good
×: defective

Abrasion: Abrasion of the printing wire after printing 100 million dots was measured.

Storage stability: Storage stability was judged from the fluidity of the ink after storage for 6 months at room temperature.

◎: good △: slightly unstable
×: defective

Corrosion: printing wire 8 in ink
The surface state when immersed at 5 ° C. for 72 hours was observed with an electron microscope, and the corrosion property was evaluated.

◎: Almost no corrosive Δ: Slightly corrosive X: Remarkably corrosive

Fluidity: It was determined whether the prepared ink had fluidity suitable for coating on a ribbon.

◎: Suitable for coating, good flowability ×: Not suitable for coating, poor flowability

[0057]

The ink composition for a printer ribbon obtained from the present invention is excellent in storage stability and fluidity. By using this ink composition, an ink which does not corrode a printing wire and reduces its abrasion. When a ribbon is obtained and further printed on a printing medium such as paper, high print density and excellent OCR suitability can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-70458 (JP, A) JP 2901352 (JP, B2) JP 8-19351 (JP, B2) JP-B 54-34009 (JP, A) B1) Japanese Patent Publication No. 57-25251 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 B41J 31/00

Claims (8)

(57) [Claims] 1. An ink composition for a printer ribbon comprising carbon black and an oil as essential components, wherein the carbon black is carbon black having an average primary particle diameter of 20 mμ or less, and further has the following general formula [I] or [I]
An ink composition for a printer ribbon, comprising a reaction product obtained by reacting the amine compound represented by I) with a polyester having a free carboxyl group. General formula General formula (In the general formula [I] or [II], R ₁ , R ₂ , R
_4, R ₅ is an alkylene group having 2 to 4 carbon atoms, R ₃
Represents an alkyl group having 1 to 4 carbon atoms. N is 1
Shows an integer of ~ 4. In the general formula [II], n
Is an integer of 2 or more, R ₄ may be an alkylene group having a different number of carbon atoms. ) 2. The ink composition for a printer ribbon according to claim 1, wherein the average primary particle diameter of the carbon black is 15 mμ or less. 3. The ink composition for a printer ribbon according to claim 1, wherein said polyester is a polyester having an acid value of 20 to 60. 4. The ink composition for a printer ribbon according to claim 3, wherein the polyester is a polyester obtained by dehydrating and condensing 12-hydroxystearic acid. 5. A carbon black having an average primary particle diameter of 20 μm or less, an oil agent, and the following general formula [I] or [II]
An ink ribbon obtained by coating a ribbon fabric with an ink composition for a printer ribbon containing, as an essential component, a reaction product obtained by reacting an amine compound represented by the formula (1) with a polyester having a free carboxyl group. General formula General formula (In the general formula [I] or [II], R ₁ , R ₂ , R
_4, R ₅ is an alkylene group having 2 to 4 carbon atoms, R ₃
Represents an alkyl group having 1 to 4 carbon atoms. N is 1
Shows an integer of ~ 4. In the general formula [II], n
Is an integer of 2 or more, R ₄ may be an alkylene group having a different number of carbon atoms. ) 6. The ink ribbon according to claim 5, wherein the average primary particle diameter of the carbon black is 15 mμ or less. 7. The ink ribbon according to claim 5, wherein the polyester is a polyester having an acid value of 20 to 60. 8. The ink ribbon according to claim 7, wherein the polyester is a polyester obtained by dehydrating and condensing 12-hydroxystearic acid.