JPH07224238A - Recording fluid for near-infrared reading, recording method using the same, and method for reading information with near-infrared ray - Google Patents

Abstract

PURPOSE:To obtain a recording fluid for near-infrared reading which absorbs near-infrared rays well, dissolves well in a solvent, and is excellent in print density and resistances to light and water. CONSTITUTION:The fluid contains an aq. medium and at least one coloring matter of which the free acid form is represented by the formula (wherein A and C are each an optionally substd. phenyl or naphthyl group; B is an optionally substd. phenylene or naphthylene group; and n is 0 or 1).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a recording liquid. Specifically, it relates to a recording liquid for reading with near infrared light.

[0002]

2. Description of the Related Art Recently, the rationalization of production and sales by strengthening physical distribution management has been increasing. Optical character recognition (OCR) devices or bar code recognition devices have become widespread as one of the technologies to support this. These recognition devices, combined with the recent development of semiconductor lasers,
Light in the near infrared region around 80 to 830 nm is used.

Conventional carbon black, nigrosine dye,
Chromium- or cobalt-containing dyes absorb near-infrared light, so they have been used to record characters and barcodes read by these recognition devices, but they have insufficient solubility or are mutagenic. Was not always satisfactory.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to provide a recording liquid which absorbs light in the near infrared region, has high solubility in a solvent, and is excellent in fastness.

[0005]

Means for Solving the Problems The present inventors have proposed the following general formula [I]

[0006]

[Chemical 2]

(In the formula, A and C represent a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group,
B represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group, and n represents a number of 0 or 1. By using an azo dye represented by
It has been found that it is possible to provide a recording liquid that is suitable for reading near infrared light and that solves the above problems. Hereinafter, the present invention will be described in detail.

The dye used in the present invention has a free acid form represented by the above general formula [I]. For more information in the general formula (I), A, a phenyl group represented by B and C, a naphthyl group, the substituent of the phenylene group or naphthylene group, -SO ₃ H group, -COOH group, an amino group, a hydroxyl group, Halogen atoms such as chlorine, bromine, and fluorine,
Acylamino group including alkylcarbonylamino group such as acetylamino group and arylcarbonylamino group such as benzoylamino group, alkyl group which may have a substituent (for example, methyl group, ethyl group, i-propyl group, n- Butyl group, sec-butyl group, t-butyl group,
A linear or branched alkyl group such as 2-ethylhexyl group; an alkyl group substituted with a phenyl group such as a benzyl group; a halo-substituted alkyl group such as a trifluoromethyl group; an alkylamino group such as a dimethylaminomethyl group A substituted alkyl group or the like), or an alkoxy group which may have a substituent (for example, a methoxy group, an ethoxy group,
Linear or branched alkoxy group such as i-propoxy group, n-butoxy group, sec-butoxy group, t-butoxy group, 2-ethylhexyloxy group; hydroxyalkoxy group such as hydroxyethoxy group; benzyloxy group, methoxy Examples thereof include a phenyl group such as an ethoxy group and a benzyloxyethoxy group, an alkoxy group substituted with an alkoxy group or a substituted alkoxy group; an alkoxy group substituted with a hydroxycarbonyl group such as a hydroxycarbonylmethoxy group). The acylamino group, alkyl group and alkoxy group each have 9 or less carbon atoms. Further, when the alkyl group or the alkoxy group has a substituent, the total number of carbon atoms including the substituent is preferably 9 or less.

Specific examples of these dyes include, for example, the following No. Examples thereof include azo dyes having structures shown in 1-27. These dyes may be used alone or in combination depending on the desired color tone, but may be used in combination with other dyes if desired.

[0010]

[Chemical 3]

[0011]

[Chemical 4]

[0012]

[Chemical 5]

[0013]

[Chemical 6]

[0014]

[Chemical 7]

[0015]

[Chemical 8]

[0016]

[Chemical 9]

Among them, in the general formula [I], A having an electron donating (donor) substituent is preferable because it absorbs near infrared light largely. As the electron-donating group, an amino group, an acylamino group, an alkyl group,
An alkoxy group and a hydroxyl group are preferred. Further, B is preferably a P-phenylene group or a 1,4-naphthylene group. These phenylene groups and naphthylene groups also preferably further have 1 to 2 substituents. Particularly preferably B
Is a 1,4-naphthylene group, it is preferable to have a —SO ₃ H group at the 6- or 7-position. In the case of 1,4-phenylene group

[0018]

[Chemical 10]

A group represented by the formula (wherein X represents a hydrogen atom, an alkyl group or an alkoxy group, and Y represents a hydrogen atom, an alkyl group, an alkoxy group or an acylamino group) is particularly preferable. Preferred as C is a phenyl group having an amino group at the P-position or a naphthyl group having an amino group at the 4-position. These phenyl groups and naphthyl groups also preferably have 1 to 2 substituents. Examples of these substituents include an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, an amino group, an acylamino group having 9 or less carbon atoms,
COOH, such as -SO ₃ H, and the like. In addition, the alkyl group and the alkoxy group further include an alkoxy group, a phenyl group,
It may be substituted with a hydroxyl group, a benzyloxy group or the like, but in this case as well, the carbon number of the alkyl group or the alkoxy group is preferably 9 or less, including the carbon number of the substituent substituting it.

The dye used in the present invention may be used as it is in the free acid form represented by the general formula [I], but when it is obtained in the salt form at the time of production, it may be used as it is. Good. Furthermore, this salt form may be converted into a desired salt form for use. In addition, some acid groups in one molecule of the dye may be in the salt form, or the salt form dye and the free acid form dye may be used in combination. Examples of such a salt form include a salt form of an alkali metal such as sodium, lithium and potassium, an ammonium salt form which may be substituted with an alkyl group or a hydroxyalkyl group, and a salt form of an organic amine. Examples of the organic amine include lower alkylamine, hydroxy-substituted lower alkylamine, carboxy-substituted lower alkylamine, and polyamine having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. In the case of the above salt form, the type of salt is not limited to one type, and a plurality of types may be mixed.

The azo dye represented by the general formula [I] has absorption in the wavelength band of 600 to 1000 nm, and particularly has a large absorption of near infrared light in the vicinity of 780 to 830 nm,
Moreover, the molecular absorption coefficient is 10 ⁴ to 10 ⁵ cm ^-1 . The compounds of the present invention are described, for example, in "New Dye Chemistry" by Yutaka Hosoda (Showa 4).
It can be produced by stacking ordinary diazotized couplings according to the description of Gihodo, page 403, bottom, line 2 to page 404, line 18. The content of the dye of the general formula [I] in the recording liquid is 0.5 to 5% by weight, particularly 2 to 4% by weight based on the total amount of the recording liquid.
About wt% is preferable.

As the solvent used in the recording liquid of the present invention, water and water-soluble organic solvents such as ethylene glycol, propylene glycol, butylene glycol,
Diethylene glycol, triethylene glycol, polyethylene glycol (molecular weight 200), polyethylene glycol (molecular weight 400), glycerin, N-methyl-
Pyrrolidone, N-ethyl-pyrrolidone, 1,3-dimethyl-imidazolidinone, thiodiethanol, dimethylsulfoxide, ethylene glycol monoallyl ether,
It preferably contains ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, sulfolane, ethyl alcohol, isopropanol, diethanolamine, triethanolamine and the like. These water-soluble organic solvents are usually used in the range of 10 to 50% by weight based on the total amount of the recording liquid. On the other hand, water is used in the range of 45 to 95% by weight with respect to the total amount of the recording liquid.

The recording liquid of the present invention contains 0.
1-10 wt% urea, preferably 0.5-5 wt% urea,
By adding a compound selected from thiourea, biuret, and semicarbazide, or by adding 0.001 to 5.0% by weight of a surfactant, the quick-drying property after printing and the printing quality can be further improved. it can. The recording liquid of the present invention can be used for writing instruments such as felt pens and water-based ballpoint pens, or for inkjet recording.
In particular, the recording liquid for inkjet recording is required to have strict performance in storage stability, ejection stability, water resistance, light resistance, etc., but the recording liquid of the present invention is also preferable in these properties, and is added as necessary. Purification such as addition of agents, pH adjustment, and filtration may be performed.

[0024]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Example 1 10 parts by weight of diethylene glycol, 3 parts by weight of isopropyl alcohol, Water was added to 3 parts by weight of the dye of No. 1 to adjust the pH to 10 with a 5% aqueous lithium hydroxide solution so that the total amount was 100 parts by weight. The composition was thoroughly mixed and dissolved, pressure-filtered with a Teflon filter having a pore size of 1 μm, and then deaerated with a vacuum pump and an ultrasonic cleaner to prepare a recording liquid.

Using the recording liquid thus obtained, ink jet recording was carried out on an electrophotographic paper (manufactured by Fuji Xerox Co., Ltd.) using an ink jet printer (trade name: HG-3000, manufactured by Epson Corp.) to obtain a high density black printed matter. Got Further, various evaluations were carried out by the following methods (a), (b) and (c).

(A) Light resistance of recorded image: A xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) was used to measure 100 on recording paper.
After irradiating for a period of time, the color difference (ΔE) of the recorded matter before and after the test was measured with a spectrocolorimeter SZ-Σ80 (manufactured by Nippon Denshoku Industries Co., Ltd.) and judged according to the following criteria. ◯: Discoloration and discoloration ΔE of 10 or less Δ: Discoloration and discoloration ΔE of 10 to 20 ×: Discoloration and discoloration ΔE of 20 or more

(B) Water Resistance of Recorded Image: Water Resistance Test Test Method After the recorded image was immersed in tap water for 5 minutes, the bleeding of the image was visually evaluated according to the following criteria. ◯: No image bleeding Δ: Image bleeding is small X: Image bleeding is large did. OD residual rate (%) = (OD value after immersion / OD value before immersion) ×
100

(C) Storage stability of recording liquid: The recording liquid was sealed in a Teflon container and stored at 5 ° C. and 60 ° C. for one month. ◯: No change X: Change These evaluation results are shown in Table 1. In addition, No. used in the first embodiment. The dye No. 1 can be produced by the following steps (A) to (E).

(A) From P-aminoacetanilide-3-sulfonic acid and 1,7-clave acid, a conventional method [for example, Yutaka Hosoda "New Dye Chemistry" (published by Gihodo on December 21, 1973) 396 ~ Page 409], the diazotization,
A monoazo compound is manufactured through a coupling process.

(B) The obtained monoazo compound and 7-amino-1-hydroxy-naphthalene-3-sulfonic acid (γ
Acid) and a disazo compound through a coupling step according to a conventional method to produce a disazo compound. (C) A triazo compound is produced from the obtained disazo compound and 2,5-diethoxyaniline by a conventional method through a diazotization and a coupling step.

(D) The obtained trisazo compound was dispersed in water and neutralized with an aqueous solution of caustic soda.
Caustic soda is added and the hydrolysis reaction is carried out at 60 ° C.
After several hours, the reaction is complete. (E) After cooling, it was neutralized to pH 9 with hydrochloric acid and salted out with sodium chloride to give the desired dye No. 1 is obtained.

Example 2 5 parts by weight of glycerin, 10 parts by weight of ethylene glycol,
The No. Water was added to 2.5 parts by weight of the dye of No. 8 and the pH was adjusted to 9 with ammonia water so that the total amount was 100 parts by weight. The composition was treated by the method described in Example 1 to prepare a recording liquid. . Printing was carried out in the same manner as in Example 1 using this recording liquid, and as a result, a high-concentration bluish black recording material was obtained. Further, various evaluations according to (a) to (c) of Example 1 were performed on the recorded matter. The results are shown in Table 1.

Example 3 10 parts by weight of diethylene glycol, 5 parts by weight of N-methylpyrrolidone, 3 parts by weight of isopropyl alcohol, the above N
o. Add water to 3 parts by weight of 16 dyes and pour with ammonia water
H was adjusted to 9 so that the total amount was 100 parts by weight, and this composition was treated by the method described in Example 1 to prepare a recording liquid. Using this recording liquid, printing was carried out in the same manner as in Example 1 to obtain a bluish black recording material. Further, various evaluations according to (a) to (c) of Example 1 were performed on the recorded matter. The results are shown in Table 1.

[0035]

[Table 1]

The absorbances at 780 nm and 830 nm of the recorded products of the recording liquids of Examples 1 to 3 are shown in Table 2, respectively, and were sufficiently detectable by the infrared absorption device.

[0037]

[Table 2]

Comparative Example 1 A recording liquid was prepared in the same manner as in Example 1 except that the dye of the following (a) was changed. Using this recording liquid, Example 1
As a result of printing in the same manner as described above, a blue recorded matter was obtained. or,
Various evaluations according to (a) to (c) of Example 1 were performed on this recorded matter. The results are shown in Table 3.

[0039]

[Chemical 11]

Comparative Example 2 A recording liquid was prepared in the same manner as in Example 2 except that the dye (b) below was used instead of the dye. Printing was carried out in the same manner as in Example 1 using this recording liquid, and as a result, a blue recorded matter was obtained. Further, various evaluations according to (a) to (c) of Example 1 were performed on this recorded matter. The results are shown in Table 3.

[0041]

[Chemical 12] Comparative Example 3 A recording liquid was prepared in the same manner as in Example 3 except that the dye (c) below was used instead of the dye. As a result of printing using this recording liquid in the same manner as in Example 1, a reddish blue recorded product was obtained.
Further, various evaluations according to (a) to (c) of Example 1 were performed on this recorded material. The results are shown in Table 3.

[0042]

[Chemical 13]

[0043]

[Table 3]

The absorbances at 780 nm and 830 nm of the recorded products of the recording liquids of Comparative Examples 1 to 3 are as shown in Table 4, and could not be detected by the infrared absorption device.

[0045]

[Table 4]

[0046]

INDUSTRIAL APPLICABILITY The recording liquid of the present invention is used for ink jet recording, writing instruments and the like. In particular, it absorbs near-infrared light well and has excellent solubility in a solvent, and its printing density and light fastness, It has excellent water resistance as well as good storage stability as a recording liquid, so it is very useful as an OCR system or bar code recognition system for reading using near infrared light. Is.

Claims (5)

[Claims] 1. An aqueous medium and a free acid form are represented by the following general formula [I].
A recording liquid for near-infrared light reading, which contains at least one of the dyes represented by [Chemical 1] (In the formula, A and C represent a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group, B represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group, and n is 0 or Represents the number 1) 2. A recording material recorded with the recording liquid according to claim 1 on a recording material is irradiated with light including near-infrared light,
A method of reading information by near-infrared light, which comprises recognizing information of the recorded product by allowing the recorded product to absorb the near-infrared light and detecting light that has not been absorbed. 3. A method for recognizing information of a recorded matter by irradiating a recorded matter with light including near-infrared light, causing the recorded matter to absorb the near-infrared light, and detecting light not absorbed. A recorded matter obtained by depositing the recording liquid according to claim 1 on a recording material so as to display information. 4. The recording liquid according to claim 1, which is for inkjet recording. 5. The recording liquid according to claim 1, wherein the near-infrared light is light having a wavelength of 780 to 830 nm.