JPH04239066A - Ink jet recording fluid - Google Patents

Abstract

PURPOSE:To obtain the title liquid having good drying properties not only on a recording paper exclusively used for ink jet recording but also on a general-purpose recording paper and to enable a high-quality ink jet recording without blurring by compounding a specified amt. of glycerin, ethanol, a water-base dye, and water for adjusting. CONSTITUTION:The title liquid at least contains 0.5-5.0wt.% glycerin, ethanol, a water-base dye, and water for adjusting. When it contains 1-10wt.% pref. 3-8wt.% ethanol and 14wt.% or lower, pref. 12wt.% or lower, the sum of glycerin and ethanol, an improved recording is obtd. A water content in the liquid of 85wt.% or higher further improves the recording. A content of glycerin lower than 0.5wt.% does not retard permeation of the fluid while a content of it higher than 5.0wt.% remarkably degrades the drying properties.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention can perform good printing not only on special recording paper prepared for inkjet recording used in inkjet recording devices, but also on other unprepared papers. Regarding possible inkjet recording liquid.

0002

[Prior Art] The inkjet recording method performs printing by ejecting liquid ink, so when recording on so-called ordinary paper such as copy paper or bond paper, 1) the ink adhering to the recording paper is quickly removed; The following properties are required: 2) it dries quickly, the characters do not rub or become smeared even when the printed surface is touched by hand or paper, and 2) there is no large smearing and the outlines and edges of the dots are vivid.

[0003] Therefore, Japanese Patent Application Laid-Open No. 55-29546 discloses a method of using a large amount of surfactant in ink, but in this case, drying properties are high, but when paper with a low sizing degree is used, There was a problem that very large bleeding occurred and high quality printing could not be obtained.

[0004] Furthermore, in the case of JP-A-56-57862, a method is proposed in which the ink is made strongly alkaline, which is said to improve drying properties and provide high-quality printing without bleeding. Although it is an effective means for acidic paper, it is not an effective means for improving drying properties for neutral paper. In addition to the above, various improvements have been made to inks to date, but to date no ink has been known that provides satisfactory recording in terms of both bleeding and drying properties. In addition, a method for preparing special recording paper for inkjet recording has been devised, but what is most desirable is to be able to print well, regardless of whether it is prepared or unprepared. Inkjet recording devices and ink are in great demand.

[0005]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide not only special recording paper prepared for inkjet recording, but also copy paper, letter paper, envelopes, notebooks, etc.
To provide an inkjet recording liquid that has good drying properties and enables high-quality inkjet recording without bleeding on general plain paper such as report paper and recycled paper.

[0006]

[Means for Solving the Problems] The inkjet recording liquid provided by the present invention has a glycerin concentration of 0.5 to 5.0.
% by weight, more preferably 0.5 to 4.5% by weight, and is characterized by comprising at least ethanol, an aqueous dye, and prepared water.

In the inkjet recording liquid of the present invention, the amount of ethanol added is 1 to 10% by weight, preferably 3 to 8% by weight, and the sum of the amounts of glycerin and ethanol added is 14% by weight or less, and more preferably 3 to 8% by weight. Better recording can be obtained by preferably setting the content to 12% by weight or less.

[0008] Further, in the inkjet recording liquid of the present invention, if the amount of prepared water added is 85% by weight or more, it becomes possible to obtain even better recording.

When printing on general plain paper using an inkjet recording liquid, the properties required of the ejected ink droplets include how thinly they spread on the paper surface when they land on the paper, and how thinly they spread on the paper surface when they land on the paper. The problem is to fix it on the paper without smearing it. In order to obtain good drying properties, good color development, and excellent print quality, the above conditions must be satisfied.

0010

[Operation] In other words, the inkjet recording liquid of the present invention spreads and adheres landed ink droplets uniformly to the paper surface using ethanol, and allows the ink droplets to penetrate into the paper without causing bleeding due to the slow penetration power of glycerin. This provides drying properties and high quality printing.

[0011] In the inkjet recording liquid of the present invention,
The amount of ethanol contained is preferably 1 to 10% by weight, more preferably 3 to 8% by weight. If it is less than 1% by weight, the ethanol in the ink droplets that land on the paper will quickly evaporate, making it impossible to spread the ink droplets thinly on the paper surface.
On the other hand, if the amount is more than 10% by weight, the ink droplets will spread too much, resulting in poor dot coloring and large bleeding on the paper, making it impossible to obtain high-quality printing.

[0012] The amount of glycerin added is 0.5% by weight to 5% by weight.
．． It is desirable that the content is 0% by weight, more preferably 0.5% to 4.5% by weight. If it is less than 0.5% by weight,
The state of fixation of ink droplets on paper becomes bead-like, similar to that of aqueous inkjet recording liquids that do not contain glycerin, and no slow penetration effect is observed. The amount of glycerin contained in the paper exceeds the limit for permeation into the paper, and even after the alcohol and prepared water have evaporated, the glycerin that has not completely permeated remains on the paper surface, causing a rapid decline in drying properties. This phenomenon occurs.

Furthermore, as a result of our intensive research, it is desirable that the sum of the amounts of glycerin and ethanol added is 14% by weight or less, more preferably 12% by weight or less. When the sum of the amounts added exceeds 14% by weight, the contact angle of the ink droplets with the paper and the surface tension will abnormally decrease, and as a result, bleeding will occur on the paper, making it impossible to maintain high print quality.

[0014]

[Example] As the dye added to the inkjet recording liquid of the present invention, any dye that can be commonly used in the field of inkjet recording technology is selected from the group consisting of food dyes, acid dyes, direct dyes, and basic dyes. Water-based dyes can be used. For example, C. I. Food Black 2, C. I. Food Blue 2, C. I. Food Violet 2, C. I.
Food Red 14, C. I. Food Yellow 4, C. I
．． acid black 2, 7, 24, 31, 52, 63,
112, 118, 119, 121, 122, 155, 1
56, C. I. acid brown 13, 46, 231,
232, 294, 295, 296, 297, C. I. Acid green 3, 5, 7, 9, 12, 16, 19, 4
4, 61, 73, 75, 76, C. I. Acid blue 102, 104, 113, 117, 120, 229, 2
34, C. I. Acid Violet 43, 78, C
．． I. Acid Red 6, 35, 52, 80, 85, 8
7, 92, 94, 111, 155, 180, 256, 3
17, 318, C. I. acid orange 1, 7, 19
, 20, 28, 74, 122, C. I. Acid Yellow 11, 135, 161, C. I. Direct Black 17, 154, C. I. Direct Brown 2, 44,
59, 106, C. I. Direct Green 1, C. I
．． Direct Blue 86, 93, C. I. Direct Violet 98, C. I. Direct Red 4, 28
,C. I. Direct Orange 6, 8, 26, C. I.
Direct Yellow 26, 86, 98, C. I. Basic brown 1, C. I. Basic green 1, 4,
C. I. Basic blue 1, 3, 5, 7, 9, 24,
25, 26, 28, 29, C. I. Basic Violet 1, 3, 10, 14, C. I. Basic Orange 2, 14, 15, 21, C. I. basic red 1
, 2, 9, 12, 37, C. I. Basic yellow 1
, 2, 11, 14, 36, etc.

The amount of these dyes added is determined by the type of medium, the solubility of the dye associated therewith, and the characteristics required of the ink by the inkjet recording method used, but it is usually about 0.1% of the total ink. -5% by weight, preferably 0.5-5% by weight. If it is too small, color development will be poor, and if it is too large, it will cause clogging of nozzles due to dye precipitation and curvature of the flight trajectory when ejecting ink droplets.

[0016] Examples and comparative examples based on the present invention will be shown and explained in detail below.

Examples 1 to 7 The components shown below, excluding ethanol, were mixed, and after stirring for 3 hours, a membrane filter with a pore size of 0.8 microns (trade name: MF-Millipore Filter, manufactured by Nippon Millipore Co., Ltd.) Pressure filtration was carried out using a commercially available product. Next, ethanol was added to the filtrate and stirred for 30 minutes to obtain recording liquids 1 to 7 of the present invention.

Example 1 (Recording liquid 1) C. I. Direct Black 154 2% glycerin by weight
3% by weight ethanol
5% by weight ion exchange water
90% by weight Example 2 (Recording liquid 2) C. I. Basic Yellow 14 2% by weight glycerin 0.
5% by weight ethanol
1% by weight ion exchange water
96.5% by weight Example 3 (Recording liquid 3
) C. I. Acid Red 35 2% by weight
glycerin
5% by weight ethanol
1% by weight ion exchange water
92% by weight Example 4 (Recording liquid 4) C. I. Acid Blue 102 2% by weight glycerin 0
．． 5% by weight ethanol
5% by weight ion exchange water
92.5% by weight Example 5 (Recording liquid 5) C. I. Food Black 2 1.5% by weight glycerin
5% by weight ethanol
5% by weight ion exchange water
88.5% by weight Example 6 (Recording liquid 6) C. I. Acid Orange 1 3% by weight
glycerin
0.5% by weight ethanol
9% by weight ion exchange water
87.5% by weight Example 7 (Recording liquid 7) C. I. Basic Blue 3 1% by weight
glycerin
5% by weight ethanol
9% by weight ion exchange water
85% by weight Comparative Examples 1 to 14 Using the same method as in Examples 1 to 7, recording liquids 8 to 21 shown below were obtained.

Comparative Example 1 (Recording Liquid 8) C. I. Acid Black 31 2% by weight ion exchange water
98% by weight Comparative Example 2 (Recording Liquid 9) C. I. Acid Brown 295 3% by weight ethanol
5% by weight ion exchange water
92% by weight Comparative Example 3 (Recording liquid 10) C. I. Direct Black 154 2% glycerin by weight
3% by weight ion exchange water
95% by weight Comparative Example 4 (Recording Liquid 11) C. I. Basic Yellow 14 2% by weight glycerin 0.
3% by weight ethanol
1% by weight ion exchange water
96.7% by weight Comparative Example 5 (Recording liquid 1
2) C. I. Acid Blue 93 2% by weight
glycerin
0.3% by weight ethanol
5% by weight ion exchange water
92.7% by weight Comparative Example 6 (Recording Liquid 13) C. I. Acid Orange 1 3% by weight
glycerin
0.3% by weight ethanol
10% by weight ion exchange water
86.7% by weight Comparative Example 7 (Recording Liquid 14) C. I. Acid Red 35 2% by weight
glycerin
5.5% by weight ethanol
1% by weight ion exchange water
91.5% by weight Comparative Example 8 (Recording Liquid 15) C. I. Food black 2 1.5% by weight glycerin 5
．． 5% by weight ethanol
5% by weight ion exchange water
88% by weight Comparative Example 9 (Recording Liquid 16) C. I. Basic Blue 3 0.5% by weight glycerin 5.
5% by weight ethanol
10% by weight ion exchange water
84% by weight Comparative Example 10 (Recording Liquid 17) C. I. Direct Green 1 3wt% Glycerin 0
．． 5% by weight ethanol
0.5% by weight ion exchange water
96% by weight Comparative Example 11 (Recording Liquid 18) C. I. Food Red 14 1.5% by weight glycerin 0
．． 5% by weight ethanol
11% by weight ion exchange water
87% by weight Comparative Example 12 (Recording Liquid 19) C. I. Direct Brown 44 2% by weight glycerin 5.
5% by weight ethanol
11% by weight ion exchange water
81.5% by weight Comparative Example 13 (Recording liquid 2
0) C. I. Acid Orange 7 3% by weight
Diethylene glycol monobutyl ether 2% by weight Ethanol
3% by weight ion exchange water
92% by weight Comparative Example 14 (Recording liquid 21
) C. I. Acid Green 73 2% glycerin by weight
4% by weight potassium hydroxide
1wt% EDTA
0.02% by weight ion-exchanged water 92.98% by weight An inkjet printer HG using the recording liquids 1 to 21 obtained above as an inkjet recording device and using a pressure printing method using PZT as an ink ejection method.
-4800 (product name/manufactured by Seiko Epson Corporation), commercially available PPC paper (manufactured by Fuji -Cler
kCorporation), product name: Neenah
Records obtained by recording on "Bond": acidic paper), report paper (manufactured by KOKUYO Co., Ltd.: acidic paper), and recycled PPC paper (manufactured by Japan Business Supply Co., Ltd., product name "My Recycle Paper": acidic paper) The printing quality and drying properties of the product were evaluated using the following methods.

(Printing quality) Printing was performed on each test paper, and after being left indoors for 24 hours, the dot level was evaluated for bleeding, color development, and edge clearness.

Bleeding ○ - There is no bleeding at all, or there is some slight bleeding, but the quality is sufficiently high △ - Bleeding is observed around the dots × - Color development with large bleeding throughout the dots ○ - The vividness of the colors is good △ - The whiteness of the paper is a little mixed, but it is not a visual problem at all × - The ink has penetrated the paper and the color is washed out ○ - The edges are clear △ - The edges around the dots are crumbling and the quality is not good. PPC paper was placed on the printed surface, a weight of 288 g/cm 2 was placed on top of it for 2 seconds to check for transfer, and the time when transfer stopped was noted.

Of the above evaluation results, Table 1 shows the results for PPC paper and bond paper, and Table 2 shows the results for report paper and recycled PPC paper.

[0023]

[Table 1]

[0024]

[Table 2]

Records obtained by printing require a faster drying time, but considering the time from when the last record is made to the paper until it is ejected, it is practical if it takes less than 25 seconds. It can be used without any problems. But 25
If the time exceeds 2 seconds, a phenomenon occurs in which the printed surface becomes smeared when the printed surface is touched even after the paper is ejected from the recording device, which poses a problem in practical use. Recording liquids 1 to 7, which are inkjet recording liquids of the present invention, have good print quality and drying properties, but in recording liquids 8 and 9 to which glycerin is not added, ink droplets penetrate the paper. The drying time is slow, and the fixation of the dye is uneven, resulting in poor color development. Furthermore, in the case of recording liquids 8 and 10 to which ethanol is not added, ink droplets do not spread thinly when they land on paper, so it takes a long time to fix them.

Regarding the amount of glycerin added, recording liquid 1
As shown in Nos. 1, 12, and 13, when the amount of glycerin added is 0.5% by weight or less, ink droplets remain on the paper surface forever, resulting in slow drying time and poor color development of the resulting records.

Furthermore, as shown in recording liquids 14, 15, and 16, if the amount of glycerin added exceeds 5% by weight, the glycerin will not completely penetrate into the paper, leading to a rapid decrease in drying time of 25 seconds or less. It becomes impossible to maintain the drying time, and furthermore,
Print quality is also not good.

When the amount of ethanol added is less than 1% by weight, the quality of the dot itself is good as shown in recording liquid 17, but the ink droplets do not spread sufficiently, making it difficult to obtain a good value for the drying time. I can't.

Furthermore, as shown in recording liquids 18 and 19, when the glycerin content exceeds 10% by weight, the drying time is
Although it is good even in a range exceeding the weight percent, abnormal bleeding occurs in printing quality and high printing quality cannot be maintained.

[0030] Figure 1 summarizes the above regarding drying properties.
is obtained. From FIG. 1, good drying properties can be obtained when the amount of glycerin is in the range of 0.5 to 5% by weight and the amount of ethanol is in the range of 1% by weight or more. Furthermore, when the amount of ethanol added exceeds 10% by weight, the drying performance becomes good regardless of the amount of glycerin added, but in that case, as can be seen from the print quality results in Table 1, the print quality is low and it is difficult to use in actual use. cause a hindrance. Figure 1 summarizes PPC paper, but the same relationship exists for bond paper, report paper, and recycled PPC paper.
Results can also be obtained on paper.

The recording liquid 20 uses diethylene glycol monobutyl ether as a penetrating solvent, which has a good drying time, but does not maintain print quality at all, making it impossible to obtain high-quality prints.

Furthermore, in the recording liquid 21, potassium hydroxide is used instead of ethanol to make the recording liquid strongly alkaline; however, in this case, acidic bond paper, recycled PPC
It has an effect on the printing quality and drying properties of paper, but it has an effect on the drying properties of PPC paper, which is acid-free paper, and report paper.
No effect is seen at all. To summarize the above results, Table 3
is obtained.

[0033]

[Table 3]

*1: Diethylene glycol monobutyl ether *2: Potassium hydroxide The criteria for printing quality are: ○ - Good in all items △ - At least 1 in the printing evaluation (Tables 1 and 2)
If there are 3 or more △ × - At least 1 in the printing evaluation (Tables 1 and 2)
If there are 3 or more x's, the criteria for determining dryness are as follows: - Drying time is 25 seconds or less x - Drying time is 25 seconds or more.

From Table 3, it can be easily determined that the underlined recording liquids of the present invention are the only recording liquids that satisfy both printing quality and drying properties.

[0036]

As described above, by controlling the amount of glycerin and ethanol contained in the recording liquid of the present invention, it can be used not only for special recording paper prepared for inkjet recording, but also for other purposes. It is possible to perform inkjet recording with high print quality even on ordinary paper such as copy paper, letter paper, envelopes, notebooks, report paper, recycled paper, etc., and also to obtain print records with good drying time. It is.

[Brief explanation of the drawing]

[Figure 1] Regarding PPC paper, glycerin in the recording liquid,
It is a graph showing the relationship between the amount of ethanol and the drying time.

Claims (6)

[Claims] 1. An inkjet recording liquid comprising at least 0.5 to 5.0% by weight of glycerin, ethanol, an aqueous dye, and prepared water. [Claim 2] The amount of glyceren added is 0.5 to 4.
．． The inkjet recording liquid according to claim 1, characterized in that the content thereof is 5% by weight. 3. The inkjet recording liquid according to claim 1, wherein the amount of ethanol added is 1 to 10% by weight. 4. The inkjet recording liquid according to claim 3, wherein the amount of ethanol added is 3 to 8% by weight. 5. The inkjet recording liquid according to claim 1, wherein the sum of the amount of glycerin added and the amount of ethanol added is 14% by weight or less, more preferably 12% by weight or less. 6. The inkjet recording liquid according to claim 5, wherein the sum of the amount of glycerin added and the amount of ethanol added is 12% by weight or less.