JPH0616983A - Ink composition - Google Patents

Abstract

PURPOSE:To provide an ink composition for ink jet recording system, good in transfer from a transferring medium to a medium to be transferred on causing no portions left untransferred, comprising a specified amount of a pigment, resin and aliphatic hydrocarbon solvent. CONSTITUTION:The composition comprising (A) 10-500wt.%, based on the component B, of a pigment, (B) a resin (e.g. polyacrylic ester, linseed oil-modified alkyd resin), and (C) an aliphatic hydrocarbon solvent. This composition is used for such a recording system as to further transfer, onto a medium to be transferred on, the ink delivered on a transferring medium through an ink jet recording head. The viscosity of the composition is pref. <=20mPa.s at points close to the nozzle in ink delivery when the temperature in the actuation of a typewriter is set at 0-50 deg.C. This composition can be obtained, for example, by dissolving the resin in the solvent followed by incorporation of the pigment and then its dispersion using a ball mill, and by filtration of the resultant homogeneous dispersion system.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ink composition used in an ink jet recording system. More specifically, it relates to an ink composition used in an inkjet recording system in which ink is ejected from an inkjet recording head onto a transfer medium, and then the ink is transferred from the transfer medium to a transfer medium.

[0002]

2. Description of the Related Art Ink jet recording is capable of high-resolution recording because it ejects minute ink droplets, and is excellent in quietness and high-speed printing during recording. Until now, as the ink composition used in the ink jet recording system, various water-soluble dyes are dissolved in water or a solvent consisting of water and a water-soluble organic solvent, and various additives are added as necessary, which predominates. (Hereinafter referred to as an aqueous dye ink). However, when recording directly with an aqueous dye ink, the print quality tends to vary depending on the paper type, the water resistance of the formed recorded image is poor, and the drying on the transferred medium is slow There are drawbacks such as

Attempts have been made to solve the above problems, for example, Japanese Patent Publication No. 55-29546 discloses.
It has been proposed to add a specific surfactant to lower the surface tension to enhance the absorbability of the ink to the transfer medium,
In Japanese Examined Patent Publication No. 56-57862, a strongly basic substance is added to raise the pH, and a sizing agent and a pulp agent, which are water resistant treatment agents for plain paper, are chemically dissolved to control the spread and absorption of dots. It has been reported that the method to
Japanese Patent No. 3675 proposes a method of adding polyvinylpyrrolidone having a molecular weight of 40,000 or more to the ink to control the spread of dots and the absorbability to plain paper, but these attempts are part of the above problems. However, it is not a measure to solve all the problems.

To solve the problem that the print quality easily varies depending on the paper type, US Pat. No. 4,538,156,
JP-A-57-70668 and JP-A-57-1230.
No. 65, JP-A-59-225958, JP-A-62-92849, etc., the above-mentioned aqueous dye ink is used to form an intermediate carrier (transfer medium) which is not absorbable from the recording head. There has been proposed a method (hereinafter, referred to as an inkjet transfer method) of ejecting and, if necessary, evaporating an ink component there, and then transferring to a target transfer medium.

[0005]

When an aqueous dye ink is used in such an ink jet transfer system,
Although there is a tendency for good print quality to be obtained regardless of the quality of the transfer medium as compared with the case of printing directly on the transfer medium, the transfer of ink from the transfer medium to the transfer medium is completely completed. However, there are problems such as residual transfer of ink on the transfer medium, and poor water resistance of the recorded image.

Therefore, an object of the present invention is that the transfer from the transfer medium to the transferred medium is good and there is no transfer residue,
An object of the present invention is to provide an ink composition that is used in an inkjet transfer system and has excellent water resistance on a transfer medium.

[0007]

The ink composition of the present invention is used in a recording system in which ink is ejected from an inkjet recording head onto a transfer medium, and the ink is further transferred from the transfer medium to a transfer medium. And at least a pigment, a resin, and an aliphatic hydrocarbon solvent, and the weight ratio of the pigment to the resin is 10 wt% to 5%.
It is characterized in that it is 00 wt%.

The weight ratio of pigment to resin weight is 500 wt.
When it exceeds%, the pigment in the ink ejected onto the transfer medium is not completely covered with the resin, so that the adhesive force to the transfer medium cannot be sufficiently secured, and the transfer medium is transferred from the transfer medium onto the transfer medium. Ink transfer is not completed completely, and ink transfer residue occurs on the transfer medium. When the weight ratio of the pigment to the resin weight is less than 10 wt% (however, the amount of the pigment added has reached an appropriate amount for the desired print density), the viscosity of the ink composition increases and the ink jet is increased. Ejection of recording ink tends to be unstable or impossible.

[0009]

EXAMPLES Examples of the present invention will be described in detail below.

The method for producing the ink composition of the present invention is described below. After adding resin to the solvent and, if necessary, adding a dispersant and dissolving it, the weight ratio of pigment to resin weight is 10 wt
To 500 wt%, add a ball mill,
Disperse with a disperser such as an attritor or sand mill to make a uniform dispersion system. Then, it can be obtained after filtering through a filter or the like to remove huge particles, dust and the like. The method for producing the ink of the present invention is not limited to this.

The ink viscosity required for an ink jet recording ink is 0 to 50 when the temperature of the printing apparatus is in operation.
When the temperature is set to ℃, from the viewpoint of ink droplet formation stability and flight stability under high speed response of the ink ejection head, 50 mPa.
It is necessary to be s or less, and more preferably 20 mPa · s or less in order to realize high-speed response.

The components of the ink composition of the present invention will be specifically illustrated below.

The pigment used in the present invention is not particularly limited. For example, for black and white, carbon blacks such as furnace black, lamp black, acetylene black and channel black, or organic pigments such as ortho-nitroaniline black. Is mentioned. For color, toluidine red, permanent carmine FB, first yellow AAA, disazo orange P
MP, lake red C, brilliant carmine 6B, phthalocyanine blue, quinacridone red, dioxane violet, pictoria pure blue, alkali blue toner, first yellow 10G, disazo yellow AAMX, disazo yellow AAOT, disazo yellow A
AOA, yellow iron oxide, disazo yellow HR, orthonitroaniline orange, dinitroaniline orange, vulcan orange, toluidine red, chlorinated para red,
Brilliant Fast Scarlet, Naphthol Red 23, Pyrazolone Red, Barium Red 2B, Calcium Red 2B, Strontium Red 2B, Manganese Red 2B, Barium Lisome Red, Pigment Scar Red 3B Lake, Lake Bordeaux 10B, Anthocin 3B Lake, Anthocin 5B Rake, Rhodamine 6
G Lake, Eosin Lake, Bengara, Fafthor Red FGR, Rhodamine B Lake, Methyl Bio Red Lake, Dioxazine Bio Red, Basic Blue 5B Lake, Basic Blue 6G Lake, Fast Sky Blue, Alkali Blue R Toner, Peacock Blue Lake, Navy blue, ultramarine blue, reflex blue 2G, reflex blue R, brilliant green lake, diamond green thioflavin lake, phthalocyanine green G, green gold, phthalocyanine green Y, iron oxide powder, rust, zinc white, titanium oxide, calcium carbonate , Clay, barium sulfate, alumina white, aluminum powder, bronze powder, daylight fluorescent pigment, pearl pigment, naphthol carmine FB, naphthol red M, permanent mosquito Min FB, Fast erotic G, disazo yellow AAA, Disazo Orange PMP, Lake red C, dioxane violet, alkali blue G toner, etc., and other pigment surface processed pigments such as graft carbon treated with resins. These may be used as a mixture of two or more kinds depending on the case.

Specific examples of the aliphatic hydrocarbon solvent that can be used in the present invention include Isopar of Exxon Co., Soltor of Phillips Petroleum Co., IP Solvent of Idemitsu Petrochemical Co., Ltd. and Shell S of Shell Petrochemical Co. of Petroleum Naphtha. ．
B. R. , Shelsol, Pegasol of Mobil Oil Co., and the like. The required properties are low toxicity, low flammability, and low odor.

Examples of the resin include polar resins such as polyacrylic ester, linseed oil-modified alkyd resin, polystyrene, rosin resin, terpene phenol resin, and alkylphenol-modified xylene resin. Further, those which are soluble in a solvent are preferable from the viewpoint of ink storability, and from the viewpoint of scratch resistance of the recorded matter after printing, the melting point or softening point of the resin is preferably 50 ° C. or higher. Moreover, these can also be used in combination of 2 or more types depending on the case.

Dispersants that can be added to the present invention as required include nonionic activators, cationic activators, anionic activators and the like. For example, sorbitan fatty acid ester (sorbitan monooleate, sorbitan monolaurate, sorbitan sesquioleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid ester (polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan) as nonionic activator Monooleate, etc., polyethylene glycol fatty acid ester (polyoxyethylene monostearate,
Polyethylene glycol diisostearate, etc.), polyoxyethylene alkyl phenyl ether (polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, etc.) and the like. Examples of the cationic activator include octadodecylamine acetate, alkyl (hardened tallow) trimethylammonium chloride, polyoxyethylene octadodecylamine, and the like. Examples of the anion activator include sodium dodecylbenzene sulfonate, sodium alkyl (beef tallow) methyl taurate, sodium oleyl methyl taurate, sodium dioctyl sulfosuccinate, and polymeric anion (polycarboxylic acid type). The characteristics required of the dispersant are those which are compatible with the solvent and can be stably dispersed in fine particles.

Although the pigment, the solvent, the resin and the dispersant which can be added as required have been described above, the present invention is not limited thereto.

Next, examples of the ink composition of the present invention will be shown.

Example 1

[0020]

[Table 1]

After the ink composition having the above composition was prepared, the following evaluation items A1 to A3 were provided to evaluate the ink composition of the present invention. The evaluation was carried out with an inkjet transfer type printer as shown in FIG.

The inkjet transfer printer shown in FIG. 1 comprises a transfer medium 1, a recording head 2, a pressure roller 3, a cleaner 4, and a heating means 7. Recording head 2
The ink ejected from the ink is transferred onto the transfer medium 1 as an ink image 50.
And a pressure roller 3 which is rotated in the direction of the arrow A in FIG.
It is transferred to the recording medium 6 by the pressure from. Then, the transfer medium 1 is cleaned by the cleaner 4 to remove the untransferred ink image.

-Evaluation items for ink composition-A1. Transfer residue on transfer medium: The weight of ink on the transfer medium before and after transferring the ink image to the transfer medium is measured,
The transfer residual rate is calculated by the following formula and evaluated according to the following classification.

Transfer residual rate = residual ink weight on transfer medium after transfer / ink weight on transfer medium before transfer × 100 ・ transfer residual rate = 0% ... suitable (⊚) ・ 0% <transfer residual rate ≦ 2% ・ ・ ・ Appropriate (○) ・ 2% <Transfer residual rate ・ ・ ・ Unsuitable (×) A2. Water resistance: After transfer recording to a transfer medium as Xerox 4042, the sample was left at room temperature for 24 hours after transfer recording, each sample was dipped in a beaker containing pure water for 1 hour, and then taken out of the recording paper. The presence or absence of is evaluated according to the following classification.

[0025]

[Table 2]

A3. Ejectability: The viscosity (η) [mPa · s] near the nozzle at the time of ejection of an ink composition prepared in a predetermined composition is measured and evaluated according to the following classification.

Η ≦ 20.0 ・ ・ ・ suitable (◎) ・ 20.0 <η ≦ 50.0 ・ ・ ・ suitable (○) ・ 50.0 <η ・ ・ ・ unsuitable (×) for each evaluation item According to the evaluation results, the ink composition of Example 1 was preferable as the ink composition used in the inkjet transfer system.

Examples 2 to 6 Table 3 shows the compositions of the ink compositions of Examples 2 to 6 of the present invention.

[0029]

[Table 3]

In Examples 2 to 6 as well, when A1 to A3 were evaluated in the same manner as in Example 1, as shown in Table 4, all were preferable as ink compositions used in the ink jet transfer system.

[0031]

[Table 4]

Comparative Examples 1 to 4 Table 1 shows the compositions of the ink compositions of Comparative Examples 1 to 4. The ink composition of Comparative Example 4 has a composition similar to that of a commercially available water-based dye ink.

Also in Comparative Examples 1 to 4, A1 to A3 were evaluated in the same manner as in Example 1, and any of the evaluation items was not preferable as the ink composition used in the ink jet transfer system. Further, as shown in Table 2, Comparative Examples 1 and 3 were not ejected because the viscosity was too large.

[0034]

As described above, the ink composition of the present invention is used in a recording system in which ink is ejected from an ink jet recording head onto a transfer medium, and then the ink is transferred from the transfer medium to a transfer medium. The resulting ink composition has good effects of excellent transfer from the transfer medium to the transfer medium and no transfer residue, and excellent water resistance on the transfer medium.

[Brief description of drawings]

FIG. 1 is a schematic view of an inkjet transfer type printer used for evaluation of the present invention.

[Explanation of symbols]

 1 Transfer Medium 2 Recording Head 3 Pressure Roller 4 Cleaner 6 Transferred Medium 7 Heating Means 50 Ink Image

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumie Uehara 3-3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation

Claims (1)

[Claims] 1. An ink composition used in a recording system, wherein ink is ejected from an inkjet recording head onto a transfer medium, and further, the ink is transferred from the transfer medium to a transfer medium, which is at least a pigment, a resin and an aliphatic hydrocarbon. Consists of a system solvent, and the weight ratio of pigment to resin is 10 wt.
% To 500 wt%, an ink composition.