JPH0236278A - Ink and method for recording - Google Patents

Abstract

PURPOSE:To obtain an ink, containing C.I. Acid Black 187 as a dye and specific components as a liquid medium and excellent in drying properties of printings on ordinary paper, shape of dots, etc., and discoloration resistance without clogging and suitable for an ink jet method. CONSTITUTION:The objective ink containing a dye which is C.I. Acid Black 187 and a liquid medium containing (A) glycerol and/or polyethylene oxide having 3-6 polymerization degree, (B) a nitrogen-containing cyclic compound (e.g., N-methyl-2-pyrrolidone) and/or ether compound of a polyalkylene oxide (e.g. ethylene glycol monomethyl ether), (C) a surfactant (e.g., alkylsulfuric ester salt) and/or a <=5C lower alcohol and (D) water.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to ink and a recording method using the ink, and more particularly to ink and recording methods using the ink, and more particularly to copy paper, report paper, and notebook paper, which is called plain paper and is generally used in offices. The present invention relates to an aqueous ink that can be printed satisfactorily on stationery, etc. and provides a black image with improved indoor discoloration, and a recording method using the ink, particularly an ink sheet recording method.

(Prior Art) Conventionally, water-based inks in which water-soluble dyes are dissolved in an aqueous medium have been used as inks for fountain pens, feltbens, etc., and inks for inkjet recording. A water-soluble organic solvent is generally added to prevent ink from clogging in ink discharge nozzles.

These conventional inks must provide an image with sufficient density, be able to print well on plain paper, not cause clogging in the pen tip or nozzle, and be able to print well on the recording material. Inkjet systems that use thermal energy require good drying properties, little bleeding, excellent storage stability, and especially excellent heat resistance, and the images formed must have sufficient light and water resistance. They are required to have the same gender, etc.

Also, inks of various hues are prepared from dyes of various hues, among which black ink is the most important ink used for both monochrome and full color images. Conventionally, C, I, and Food Black 2 have been mainly used as dyes for these black inks in consideration of various performances (Japanese Patent Laid-Open Nos. 59-93766 and 59-9).
(See Publication No. 3768).

(Problems to be Solved by the Invention) Among the various required performances mentioned above, it is particularly important to achieve both good recording on plain paper and light resistance of images formed on coated paper.

First, the problem with good recording on plain paper is that paper commonly used in offices, such as notebook paper, report paper, copy paper, and letter paper, cannot be used.

In other words, when printing on the various types of paper mentioned above using conventional inkjet printer ink, the printed ink spreads along the paper fibers, resulting in irregular dot shapes and so-called smearing. Ruled lines, small letters, and complex kanji such as those specified as JIS Level 2 were often unclear and difficult to read.

In addition, the paper used for writing on the surface is made with a "
Because a process called "size" is done in the paper manufacturing process,
When printing with an inkjet printer, it is difficult for the ink to penetrate inside the paper, and the drying of the printed area is poor, so it is difficult to print with an inkjet printer.
There were problems such as the prints getting rubbed on the printer cover and getting dirty, and ink getting on your hands when you touched the prints.

Next, regarding the lightfastness of images, in the past, fading due to direct sunlight and various types of illumination light was the main problem, and these fading problems were solved by selecting dyes with excellent lightfastness. There is progress.

However, recently, in addition to these fading problems, the problem of image discoloration has also been brought into focus. In other words, images made with conventional ink suffer from not only fading but also discoloration, and discoloration does not change much in density, but changes in hue.Especially in black ink, which is used in the largest amount, The problem of brown discoloration, in which black color changes to brown, is an important problem, and especially in the case of full-color images, image quality rapidly deteriorates due to this brown discoloration.

This brown discoloration problem progresses even indoors where there is no direct sunlight, and the discoloration is also accelerated depending on the type of recording material used to form the image. This brown color problem was unavoidable in Footblack 2.

In particular, in the case of so-called coated paper, in which an ink-receiving layer containing a pigment and a binder is formed on a base material such as paper, in order to improve image quality such as ink color development, clarity, and resolution, In the case of paper, even inks that cause little discoloration problems cause significant brown discoloration, and this problem cannot be solved simply by selecting dyes with good light resistance.

Therefore, an object of the present invention is to provide an ink that can be used in various recording methods, is particularly suitable for inkjet printers, and can solve the problems that conventional inks have, namely, not only coated paper but also fibers on the recording surface. An object of the present invention is to provide an ink that solves problems such as ink bleeding and slow drying of printed matter when printed on exposed recording materials, and a recording method using the ink.

Also, another objective of the present invention is that during browning on coated paper,
It is an object of the present invention to provide an ink and a recording method that can provide an image that does not produce an image.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention consists of two inventions, and the first invention is an ink containing a dye and a liquid medium.
Acid Black 187, and the liquid medium is (a) glycerin and/or polyethylene oxide with a degree of polymerization of 3 to 6, (b) an ether compound of a nitrogen-containing cyclic compound and/or polyalkylene oxide, (c) a surfactant. and/or a lower alcohol having 5 or less carbon atoms and (d) water, the second invention is an ink characterized by containing:
In a recording method performed by applying ink to a recording material, the ink contains a dye and a liquid medium, the dye is C, I, or acid black 187, and the liquid medium is (a) glycerin and/or polymerization degree 3. This is a recording method characterized by comprising: (C) a surfactant and/or a lower alcohol having 5 or less carbon atoms; and (d) water.

(Function) By selecting a specific dye as the ink dye and selecting the composition of the liquid medium, it is possible to improve the ink's storage stability, clogging prevention, ejection stability, frequency response, heat resistance, etc. Provided is a black ink which has excellent physical properties and provides images with problems such as blurring, density and indoor discoloration, ie, brown discoloration, of images even when used on coated paper as well as regular paper.

In addition, in the second aspect of the present invention, it is possible to provide a high-density black image without bleeding or browning even on coated paper using the above ink.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The black dyes used in the ink of the present invention include C, I,
Acid Black 187, and this black dye is generally a soda salt of a water-soluble group such as a sulfonic acid group, but the present invention is not limited to these soda salts, and their counter ions are potassium, lithium, ammonia, etc. , organic amines, etc. have the same effect, and the present invention also includes dyes containing these other counter ions.

Since the above c, r, acid black 187 is a greenish black color, other toning dyes may be blended with this dye to eliminate the greenishness and enhance jet blackness.

The amount of the dye used in the ink of the present invention is not particularly limited, but - numerically, it is 0.1 to 15% by weight, preferably 0.3 to 10% by weight, more preferably 0.3 to 10% by weight, based on the total weight of the ink. The amount accounts for 0.5 to 5% by weight.

The aqueous medium used in the ink of the present invention has a specific composition, and by having this composition, various physical properties required of the ink are achieved, such as prevention of image bleeding, prevention of dye migration, and storage stability. It has been found that properties such as performance, ejection stability, frequency response, and heat resistance are improved.

The liquid medium of the ink of the present invention contains (a) glycerin and/or polyethylene oxide with a polymerization degree of 3 to 6 as a component that improves the preservability and clogging prevention properties of the ink, and these components account for approximately It is within the range of 1 to 30% by weight, preferably 2 to 25% by weight, and more preferably 3 to 20% by weight. Outside this range, the storage stability and clogging prevention properties may become unsatisfactory, or the paper may become unsatisfactory. It becomes impossible to keep good records.

In addition, in the present invention, (b) a nitrogen-containing cyclic compound and/or a nitrogen-containing cyclic compound and/or a nitrogen-containing cyclic compound are used as components for improving color development, density improvement, and ejection stability of the dye.
or an ether compound of polyalkylene oxide, and these components account for about 0.1 to 50% by weight, preferably 0.5 to 35% by weight, and more preferably 1 to 20% by weight in the total amount of the ink. If the value is outside this range, the performance shown in F becomes unsatisfactory.

Examples of the nitrogen-containing cyclic compound in - include N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc., and examples of the ether compound of polyalkylene oxide include: ethylene glycol mono- or dimethyl (or ethyl) ether, diethylene glycol mono- or dimethyl (or ethyl) ether,
Examples include triethylene glycol mono- or dimethyl (or ethyl) ether, tetraethylene glycol mono- or dimethyl (or ethyl) ether, and the like.

In addition, in the present invention, (C) a surfactant and/or a lower alcohol having carbon number of 5 or less is included as a component for improving the frequency response and fixing properties of the ink, and among the stiff components, the surfactant is included in the total amount of the ink. about 0.001 to 2% by weight, preferably 0.005 to 1% by weight, more preferably 0.0%
The content is in the range of 1 to 0.5% by weight, and outside this range, the above performance becomes unsatisfactory. In addition, the lower alcohol is about 0.1 to 15% by weight, preferably 0.
．． The content is in the range of 3 to 10% by weight, more preferably 0.5 to 5% by weight, and outside this range the above performance becomes unsatisfactory.

Examples of the surfactants include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl Sulfate ester salt, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene oxypropylene block polymer Examples of the lower alcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
Examples include ec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and pentyl alcohol.

Further, the water used (d) is preferably deionized water, and accounts for 40% by weight or more, preferably 60% by weight, and more preferably 80% by weight or more of the entire ink. This is not preferable because a large amount of low-volatile organic solvent remains in the resulting image, causing problems such as dye migration and image blurring.

In addition to the above-mentioned components, the ink of the present invention may optionally contain:
PHA adjusters, viscosity modifiers, surface tension modifiers, and the like may be included. Examples of the pH A9 agent used in the above ink include various organic amines such as jetanolamine and triethanolamine, and inorganic agents such as alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide. Examples include alkaline agents, organic acid salts such as lithium acetate, organic acids, and mineral acids.

The ink of the present invention as described above has a viscosity of 1 at 25°C.
It preferably has physical properties of 20 to 20 cP, preferably 1 to 10 cP, more preferably 1 to 3 cP, a surface tension of 30 dyne/cm or more, preferably 40 dyne/cm or more, and a pH of about 4 to 10.

The recording method of the present invention is a recording method characterized by using the above-mentioned ink, and the recording method and recording material are not particularly limited, but in particular, the recording method is an inkjet method, and the recording material is plain paper. Of course, from the viewpoint of light resistance, the method of using coated paper is particularly effective.

The inkjet method may be any conventionally known method and is not particularly limited, but in the present invention, for example, the method described in Japanese Patent Application Laid-Open No. 54-59936 is used, in which the ink is rapidly heated by the action of thermal energy. A method is useful in which a volume change is caused and ink is ejected from a nozzle by the acting force caused by this state change.

In other words, with this method, in the case of conventional ink, there was a risk that foreign matter would settle on the heat-generating head in the device, causing problems such as ink non-ejection, but the ink of the present invention is free from such foreign matter. Stable recording is possible because no deposits occur.

The recording material used in the present invention can be any recording material such as general plain paper, high-quality paper, coated paper, plastic film for OHP, etc., but especially when coated paper is used, light resistance A remarkable effect is produced in terms of sex.

These coated papers are made of paper such as plain paper or high-quality paper, and have an ink-receiving layer that serves as a pigment and binder on the surface to improve color development, clarity, dot shape, etc. with ink. That is.

In the case of these coated papers, fine pigments such as synthetic silica with a BET specific surface area of 35 to 650 rn'/g are used as pigments to provide images with excellent color development and clarity, but conventional inks cannot be used. When used, although the theoretical reason for this is unknown, images using black ink in particular have a noticeable problem of brown discoloration over time, and this is a major problem not only for black monochrome images but also for full color images.

In addition, similar to these coated papers, recording materials that have a thin layer of pigment and binder on a paper base material, and in which fibers of the base paper are mixed, also cause similar problems. There is.

It has been found that even when a black monochrome image or a full color image is formed using the ink of the present invention on the coated paper as described above, the problem of brown discoloration as described above does not occur. Therefore, according to the method of the present invention, the BET specific surface area is 35 to 16
Not only coated paper using a pigment of 50 m'/g, coated paper using a pigment with a BET specific surface area of less than that, but also Juntsu paper and other recording materials can be used to prevent long-term indoor discoloration. It is possible to provide recorded images that do not occur.

Incidentally, although the inkjet recording method and the various recording materials described above are publicly known and have been proposed by the applicant, these recording methods and recording materials are not used in the present invention as they are. Can be used.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight.

Examples 1 to 6 The following components were mixed, sufficiently stirred to dissolve, and filtered under pressure using a Fluorobor filter (manufactured by Sumitomo Electric Industries, Ltd.) with a pore size of 0.45 μm to prepare six types of inks of the present invention.

-1 Ink C, I, Acid Black 187 3 parts Glycerin 15 parts Triethylene glycol monomethyl ether 2 parts Pluronic L-44 (trade name, nonionic surfactant, manufactured by Jiryuka) 0.01 part Water
80 copies
2 parts C, I, acid black 187 2 parts glycerin 12 parts N-methyl-2-
Pyrrolidone 3-part Emulgen PP150 (trade name, nonionic, 1-side active agent, manufactured by Kao)
0.02 part water
83 parts-3 Nc C, l Acid Black 187 3 parts triethylene glycol 10 parts tetraethylene glycol dimethyl ether 4 parts Emulgen 985 (trade name, nonionic surfactant, manufactured by Kao) 0.1 part water
83 parts Real 5 parts A compound 23 υ 1 parts c, r, acid black 187 4 parts Tetraethylene glycol 2 parts Glycerin
6 parts 1,3-dimethyl-2-imidazolidinone 5 parts ethanol
3 parts water
80 parts-5 ink [:, 1. Acid Black 187 3 parts Pentaethylene glycol 10 parts Tetraethylene glycol dimethyl ether 4 parts Emulgen PP150 (trade name, nonionic surfactant, manufactured by Kao) 0.1 part Water
83 parts-6 ink ゛C, I, acid black 187 3 parts triethylene glycol 10 parts isopropanol 4 parts Emulgen PP150
(Product name, nonionic surfactant, manufactured by Kao)
0.1 part water
Six types of comparative inks were prepared in the same manner as in the examples.

Ink 1 C, I, Food Black 2 2.5 parts diethylene glycol 30 parts N-methyl-
2-pyrrolidone 15 parts water
Amount to make the total 100 parts -2 Ink C, I, Footblack 2 3 parts Glycerin 15 parts Triethylene glycol monomethyl ether 2 parts Pluronic L-44 (trade name, nonionic surfactant, manufactured by Asahi Denka) 0. 01 part water
80 parts-3 Nc C, R, Acid Black 187 3 parts diethylene glycol 15 parts triethylene glycol monomethyl ether 2 parts Pluronic L-44 (trade name, nonionic surfactant, manufactured by Asahi Denka) 0.01 part water
80 parts Ink 4 C, R, Acid Black 187 3 parts Polyethylene oxide (degree of polymerization 7) 15 parts Triethylene glycol monomethyl ether 2 parts Pluronic L-44 (trade name, nonionic surfactant, manufactured by Asahi Denka) 0.01 part water
80 parts - 5 parts C, R, acid black 187 3 parts glycerin 15 parts triethylene glycol monomethyl ether 2 parts water 8
0 parts" 6 ink C, I, acid black 187 3 parts glycerin 15 parts ethylene glycol 2 parts Bluronic L-44 (
Product name, nonionic surfactant, manufactured by Asahi Denka)
0.01 part water
80 copies Usage example Inkjet printer that uses a heating element as an ink ejection energy source (nozzle size 22 x 33 μm,
The following recording material A was prepared by mounting the inks of Examples 1 to 6 and Comparative Examples 1 to 6 on a 256-nozzle, 1KHz drive).
The dryness of printing when printing on C to C, the rate of occurrence of bleeding,
Printing - We evaluated clogging when reprinting after stopping printing, recovery from clogging when reprinting after long printing stops, frequency response, and color fastness, and the obtained results are shown in Tables 1 and 2. Shown below.

Recording material A: Coco-8 paper M for inkjet (product name,
(manufactured by Mitsubishi Paper Industries) Recording material B: Coco-8 paper C-3 for inkjet (product name, manufactured by Jujo Paper Industries) Recording material C: Copy paper (:anon PAPERDR
Y (Product name, manufactured by Canon Sales ■) (Evaluation method and evaluation criteria) (1) Printing dryness Regarding the printing dryness, after printing alphanumeric characters on a commercially available recording material C using a printer, 10. 20.30.40.5
After 0 and 60 seconds, it was rubbed with a filter paper [Toyo Roshi Co., Ltd. No. 2 (trade name)] and judged based on the number of seconds until the printed area was no longer dirty (at 20°C ± 5°C, 50 ± 10% RH). measurement).

○: Within 20 seconds △: Within 20 to 40 seconds After leaving for more than 1 hour, the number of bleeding dots was counted using a microscope and expressed as a percentage (20±5℃, 50±1O%RH).
(Printed in ).

○: Less than 10% △: 11 to 30% After filling with ink and printing alphanumeric characters on the recording material C for 3 minutes continuously, stop printing, leave it for 3 minutes with no cap etc., then print alphanumeric characters again and check if the characters are faded. Judgment was made based on the presence or absence of defective parts such as , defects, etc. (left at 20±5° C., 50±10% RH).

○No defects starting from the knee letter.

△A part of the knee letters is faded or missing.

×The knee character cannot be printed at all.

(4) Recovery from clogging when reprinting after a long printing stop After filling the printer with the specified ink and printing alphanumeric characters on the recording material C continuously for 10 minutes, stop printing and replace the cap, etc. After leaving it unused for 7 days, perform an operation to recover from clogged nozzles.
It was determined whether normal printing without defects etc. was possible (60℃, I
Leave it at 0±5%R1 (→.

○: Normal printing is possible after 1 to 5 recovery operations.

△: Normal printing is possible after 6 to 10 recovery operations.

X: Normal printing is possible after 11 or more recovery operations.

(5) Frequency Responsiveness The driving frequency was set at 2 KHz, and the printing condition of the obtained printed matter, that is, the condition of fading and white spots, and the condition of landing point defects such as splash and wobbling, were observed and evaluated with the naked eye.

The followability of the ink to the 02 frequency is good, and no blurring, white spots, or poor landing points are observed in both solid printing and character printing.

△: No fading or white spots are observed in character printing, but poor impact points are observed in some areas. In addition, in the dark printing, fading and white spots are observed in about 1/3 of the entire solid area.

×: There are many scratches and white spots in the back printing, and there are also many scratches and poor landing points in the character print.

(6) Colorfastness After printing a solid black pattern of 10 mm x 30 mm on recording materials A, B, and C at a driving frequency of 1 Hz, the ozone concentration was constantly set to 0.1 ± 0.05 volume as a method of accelerating discoloration. The printed matter was left for 30 minutes in a light-shielded tank maintained within the range of
(according to S z8730).

○: ΔE”ab<5 △: 5≦ΔE”ab≦10 ×: ΔE”ab>10 (Left below margin) Salmon - "2" Y-Sexual impact response and drunkenness ":" -Sex (A) (B) (C) Coll≦ζj〈 (Evaluation result) Aim 31 !Sl 迭△ 周j”lighting △ ○ ○ △ × △resistant-jL
”1-Sex (A)xx ○ ○ ○ ○(B)xx
○ OO0 (C) to △ OOO○ (Effects) According to the present invention as described above, - not only is it excellent in the numerically required performance of printing on plain paper such as dryness and dot shape, but also It has become possible to form images with excellent color fastness even on coated paper without clogging.

Patent applicant: Canon Co., Ltd.

Claims (4)

[Claims] (1) In an ink containing a dye and a liquid medium, the dye is C
, I, Acid Black 187, and the liquid medium is (a) glycerin and/or polyethylene oxide with a degree of polymerization of 3 to 6, (b) a nitrogen-containing cyclic compound and/or an ether compound of polyalkylene oxide, (c) An ink characterized by containing a surfactant, a lower alcohol having 5 or less carbon atoms, and (d) water. (2) In a recording method performed by applying ink to a recording material, the ink contains a dye and a liquid medium, the dye is C, I, or Acid Black 187, and the liquid medium is (a) glycerin and/or Contains polyethylene oxide with a polymerization degree of 3 to 6, (b) a nitrogen-containing cyclic compound and/or an ether compound of polyalkylene oxide, (c) a surfactant and/or a lower alcohol having 5 or less carbon atoms, and (d) water. A recording method characterized by. (3) The recording method according to claim 2, wherein recording is performed using an inkjet method. (4) The recording method according to claim 2, wherein the recording material has an ink-receiving layer made of a pigment and a binder on its surface.