JP3484467B2 - Inkjet recording method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can secure long-term ejection reliability of a recording apparatus by using an ink jet recording method, particularly by using an ink containing a nozzle cap having a specific moisture permeability and a specific wetting agent. The present invention relates to an inkjet recording method.

[0002]

2. Description of the Related Art In recent years, ink jet printers have been rapidly spread due to advantages such as low noise and low running cost. One of the problems in ink jet printers is occurrence of non-ejection nozzles due to clogging of ink. To be It is considered that this is mainly due to the fact that the water content of the ink in the nozzle portion evaporates, and the viscosity of the ink increases or the dye or the like in the ink is deposited, and various measures have been proposed so far.

As a measure against the apparatus, not only is a cap provided on the nozzle, but according to Japanese Utility Model Laid-Open No. 58-53635, ink is filled in a part of the space formed between the cap and the head. It is suggested to do so. However, in this case, although there is no problem that the physical properties of the ink inside the nozzles and inside the ink chambers change, when the water filled in the space evaporates, the viscosity increases and the ink around the head and inside the cap increases. There was a problem that it became difficult to clean.

Further, Japanese Patent Application Laid-Open No. 64-5852 discloses that
Proposals have been made to fill a wetting liquid instead of a relatively expensive ink, but in this case, a wetting liquid is separately required in addition to the conventional ink, and liquid exchange at the time of filling and thickening is required. Therefore, a circulating system device is required, which causes a cost problem and makes it difficult to downsize the device.

Further, it has been proposed to prevent water evaporation from the nozzle by providing an ink absorber in the cap. However, if the absorber itself is contaminated, it is possible that the nozzle surface is rubbed with dirt. , It's not a sufficient measure. The proposal from the ink side for these devices is to use a wetting agent with high water retention and low viscosity and high dye solubility in regard to thickening of ink and evaporation of dye due to water evaporation. Although proposals and improvements have been made, they are not sufficiently satisfactory, and the entire apparatus currently relies on a reliability maintaining mechanism such as suction and wiping.

[0006]

SUMMARY OF THE INVENTION The present invention provides an ink jet recording method which solves the above-mentioned problems of the prior art, in particular, which can prevent clogging of the nozzle portion of an ink jet recording apparatus and ensure long-term ejection reliability. The purpose is to

[0007]

According to the present invention, firstly, an ink containing an ink jet recording apparatus in which a nozzle portion is covered with a cap contains a colorant, a wetting agent and a surfactant which are dispersed or dissolved in water. In the method for loading and recording, a cap of 20 ° C. and 60% R. It is formed from a member having a moisture permeability in H of 5 × 10 ⁻⁷ g / mm ² / hour or less, and the ink has a moisture content of 30% when evaporated by 40%.
C. viscosity at 5 mPa.s. An ink jet recording method using an ink of s or less.

Secondly, in the ink jet recording method described in the first aspect, the ink cartridge is provided in the ink jet recording apparatus, and the atmosphere release port of the ink cartridge and the connecting portion between the ink cartridge and the print head are within a guaranteed period of use of the cartridge. An ink jet recording method is provided, wherein the total amount of evaporated water is less than 10% of the initial ink capacity filled in the cartridge.

Thirdly, in the ink jet recording method described in the first or second aspect, the amount of the wetting agent contained in the ink is 10% by weight or more and 30% by weight or less, and the dye concentration is 6% by weight. An inkjet recording method is provided, which is characterized by:

Fourth, there is provided the ink jet recording method according to the third aspect, wherein the vapor pressure of the wetting agent at room temperature is 0.1 mmHg or less.

Fifth, there is provided an ink jet recording method according to the third or fourth ink jet recording method, wherein the wetting agent is a mixture of glycerol and diethylene glycol.

The present invention will be described in detail below. As described above, according to the present invention, the cap (reference numeral 3 in the drawing) provided on the front surface of the nozzle is 20 in order to prevent the nozzle portion from being clogged in the inkjet recording apparatus that records by ejecting the recording liquid from the nozzle. 60% R.C. The recording liquid (ink) is formed of a member having a moisture permeability in H of 5 × 10 ⁻⁷ g / mm ² / hour or less, and the recording liquid (ink) used is dispersed or dissolved in water. Viscosity of 6% at 30 ° C with 40% water content
mPa. It was found that long-term ejection reliability can be obtained when recording is performed using an ink of s or less.

The moisture permeability referred to here means JIS (Z020
8) or measured according to the method specified in ASM test method (D895-94),
20 ° C. 60% R. Moisture permeability in H is 5 × 10 ^-7 g / m
When the cap portion is formed of a member having a larger size than m ² / hour, the evaporation of water from the nozzle portion is increased and the nozzle portion is apt to be clogged.

The material and shape of the cap are not particularly limited as long as they are excellent in adhesiveness to the nozzle surface, do not cause deterioration by ink, and satisfy the conditions related to the above-mentioned moisture permeability. Is a fluororubber or butyl rubber and is not particularly limited as long as it satisfies the above conditions regarding the thickness of the member, etc., but considering the workability and durability, the thickness is preferably 1 to 5 mm. And preferably 1.5 to 3 mm. Further, the ink used at the same time also contains a colorant, a wetting agent and a surfactant which disperse or dissolve in water, and has a viscosity of 6 mPa.s at 30 ° C. when 40% of water in the ink is evaporated. The raw materials used are not particularly limited as long as they are s or less.

In an ordinary printer, there are four possible locations where water in the ink evaporates: the atmosphere opening port provided in the cartridge, the cartridge body, the connecting portion between the cartridge and the head, and the nozzle portion (see FIG. 3). ).
The largest amount of evaporation is evaporation from the atmosphere opening port (in FIG. 3, reference numeral 9 indicates the position where the atmosphere opening port of the cartridge is provided, and a groove is cut on the upper surface). ), This is considered to lead to an increase in the viscosity of the entire ink. However, if the total water evaporation amount during the cartridge use guarantee period is 10% or less of the initial ink amount, there is no particular problem. In order to make the cartridge with 10% or less of the initial ink amount, it is desirable to make the diameter of the atmosphere opening port provided on the upper part of the cartridge small and make it long. On the other hand, evaporation from the nozzle causes a local increase in viscosity, which is a direct cause of clogging.

In general, many proposals have been made from the ink side with respect to clogging caused by precipitation of water due to evaporation of water in the nozzle portion or thickening of the ink. In particular, addition of a wetting agent, a dye dissolving agent, etc. The formulation is devised so that stable ejection can be performed even when a certain amount of water has evaporated. Commonly used wetting agents include glycols, glycol ethers, nitrogen-containing cyclic compounds, and the like, each of which has advantages and disadvantages. Glycols have a low vapor pressure and high dye solubility, but have the drawback of high viscosity. Glycol ethers have lower viscosities than glycols, but are inferior in dye solubility, and easily deteriorate when a polymer member is used for the head. Nitrogen-containing cyclic compounds have low viscosity and high dye solubility, but they have the drawback that they are more likely to evaporate than glycols.

Taking these into consideration, the wetting agent amount is most reliable when used in the range of 10% or more and 30% or less, and more preferably 15% or more and 25% or less. When the amount of the wetting agent is less than 10%, the dissolution stability of the dye is insufficient, and the dye is likely to be deposited in the nozzle portion. When the amount of the wetting agent exceeds 30%, thickening of the ink becomes a problem.

In addition, there is often a trade-off relationship between the dissolution stability of the dye contained in the ink and the water resistance, and in general, the dye having high water resistance has low solubility. Therefore, when using a highly water-resistant dye, the dye concentration should be 6
% Or less, which is also related to the image density, but more preferably in the range of 3% to 5%. If the dye concentration exceeds 6%, the viscosity becomes too high, and non-ejection nozzles are likely to occur, and the dye is likely to precipitate when water is evaporated.

As the dye used in the present invention, a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye, and an edible dye in the color index and having excellent water resistance and light resistance is used. . Specific examples of the dye will be presented below, but the present invention is not limited thereto.
Acid dyes and food dyes include C.I. I. Acid Yellow 17,23,42,44,
79, 142 C.I. I. Acid Red 1,8,13,14,18,
26, 27, 35, 37, 42, 52, 82, 87, 8
9, 92, 97, 106, 111, 114, 115, 1
34, 186, 249, 254, 289 C.I. I. Acid Blue 9,29,45,92,24
9 C. I. Acid Black 1, 2, 7, 24, 26,
94 C.I. I Food Yellow 3,4 C.I. I. Hood Red 7, 9, 14 C.I. I. Food Black 1,2 Direct dyes include C.I. I. Direct Yellow 1, 12, 24, 26,
33, 44, 50, 86, 120, 132, 142,
144 C.I. I. Direct Red 1, 4, 9, 13, 17,
20, 28, 31, 39, 80, 81, 83, 89,
225, 227 C.I. I. Direct Orange 26, 29, 62, 10
2 C. I. Direct Blue 1, 2, 6, 15, 22,
25,71,76,79,86,87,90,98,1
63, 165, 199, 202 C.I. I. Direct Black 19,22,32,3
8, 51, 56, 71, 74, 75, 77, 154,
168,171 basic dyes include C.I. I1. Basic Yellow 1, 2, 11, 13,
14, 15, 19, 21, 23, 24, 25, 28,
29, 32, 36, 40, 41, 45, 49, 51, 5
3, 63, 64, 65, 67, 70, 73, 77, 8
7,91 C.I. I. Basic Red 2,12,13,14,1
5,18,22,23,24,27,29,35,3
6,38,39,46,49,51,52,54,5
9, 68, 69, 70, 73, 78, 82, 102,
104, 109, 112 C.I. I. Basic Blue 1,3,5,7,9,2
1, 22, 26, 35, 41, 45, 47, 54, 6
2,65,66,67,69,75,77,78,8
9, 92, 93, 105, 117, 120, 122,
124, 129, 137, 141, 147, 155 C.I. I. Basic Black 2,8 reactive dyes include C.I. I. Reactive Black 3,4,7,11,1
2,17 C.I. I. Reactive Yellow 1, 5, 11, 13,
14, 20, 21, 22, 25, 40, 47, 51,
55, 65, 67 C.I. I. Reactive Red 1,14,17,25,
26, 32, 37, 44, 46, 55, 60, 66,
74, 79, 96, 97 C.I. I. Reactive blue 1,2,7,14,1
5,23,32,35,38,41,63,80,95 and the like are preferable, and acid dyes and direct dyes are particularly preferable.

The wetting agent used in the present invention preferably has a low vapor pressure, and particularly has a vapor pressure of 0. High reliability can be obtained when it is 1 mmHg or less. Specific examples of such a wetting agent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, glycerol, 1,5-pentanediol,
1,6-hexanediol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-
Polyhydric alcohols such as butanetriol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether,
Polyhydric alcohol alkyl ethers such as tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2 Examples thereof include nitrogen-containing heterocyclic compounds such as -pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidinazolidinone, and ε-caprolactam, but the present invention is not limited thereto.

Of these, particularly preferred are diethylene glycol and glycerol. Diethylene glycol has a high boiling point, and the solubility of the dye is remarkably good, but the viscosity is also low, which makes it ideal for preventing ink from drying.
Glycerol has a high viscosity and therefore has a limited amount used, but it has a high solubility for inorganic salts and can be stably dissolved even when the degree of purification of the dye is low. Therefore, when a mixture of these two types is contained as a wetting agent, higher reliability recording can be obtained even when a highly water-resistant dye is used.

In the present invention, depending on other purposes,
Surfactant, penetrant, antiseptic and antifungal agent, metal corrosion inhibitor,
A water-soluble ultraviolet absorber, a water-soluble infrared absorber, etc. can also be added.

[0023]

[Example 1]

<< Ink Composition >> Fast Cyan 2 (manufactured by Zeneca Dye Company) 3% by weight Diethylene glycol 8% by weight Glycerin 2% by weight Surfactant BT-7 (manufactured by Nikko Chemicals) 1% by weight Ion-exchanged water 86% by weight The above ink composition Was dissolved with stirring at room temperature, the pH was adjusted to 10.5 with lithium hydroxide, and then 0.22
The ink of Example 1 was prepared by filtering through a Teflon filter of μm and deaeration for about 30 minutes.

Next, the following tests were conducted on the ink prepared. The results are shown in Table 1. (1) Viscosity Measurement at 40% Moisture Evaporation The ink of the above Example 1 was placed in a beaker, the water content was evaporated in a constant temperature bath at 50 ° C. until the weight reached the initial 60%, and then the viscosity at 30 ° C. was measured. It was measured. (2) Reliability during printing pause In an inkjet printer, a cap during operation,
Regarding how long the printing can be resumed without cleaning or the like, the reliability was evaluated by the time (seconds) until the ejection direction shifts or the weight of the ejected droplets changes. As an evaluation standard, the one in which the injection reliability of 500 seconds or more was obtained is ◯, and 500 seconds or more was 500
Less than seconds was evaluated as Δ and less than 200 seconds was evaluated as x. (3) The printer used in the long-term ejection reliability test (2) was filled with the prepared ink, and the material (butyl rubber) having a moisture permeability A (= 3 × 10 ⁻⁷ g / mm ² / hour) and moisture permeability Rate B (= 1 × 10 ⁻⁶ g / mm ² /
Time) with a cap made of material (styrene-butadiene rubber) attached, left at room temperature for 3 months and 6 months, and then printed without cleaning. Pixel diameter and dot position before and after leaving The accuracy was measured. Regarding the pixel diameter, when the change in the pixel diameter before and after leaving is less than 15% of the pixel diameter before leaving, it is marked as 15 to 30.
Less than% was evaluated as Δ, and more was evaluated as x. Regarding the dot position accuracy, when the dot line of one nozzle row is approximated to a straight line, the standard deviation of the deviation from the straight line is compared before and after being left unattended. If the risk rate is within 1%, the risk rate is within 5%. △, other than that was marked x.

Example 2 << Ink Composition >> C.I. I. Direct Black 168 4% by weight Diethylene glycol 15% by weight Glycerin 5% by weight Surfactant ECTD-3NEX (manufactured by Nikko Chemicals Co., Ltd.) 1% by weight Ion-exchanged water 75% by weight The above ink composition was treated at room temperature in the same manner as in Example 1. After dissolving with stirring and adjusting the pH to 10.5 with lithium hydroxide, this was filtered through a 0.22 μm Teflon filter, and deaeration was performed for about 30 minutes to prepare the ink of Example 2. did. The tests (1) to (3) were performed on this ink in the same manner as in Example 1. The results are shown in Table 1.

Example 3 << Ink Composition >> C.I. I. Direct Red 227 (manufactured by Daiwa Kasei Dye Co., Ltd.) 3% by weight Diethylene glycol 18% by weight Glycerin 2% by weight Surfactant ECTD-3NEX (Nikko Chemicals) 1% by weight Ion-exchanged water 76% by weight Similarly, it was dissolved at room temperature and dissolved, and the pH was adjusted to 0.
It is filtered with a 22μm Teflon filter, and further 30
The ink of Example 3 was prepared by degassing for about a minute. With respect to this ink, in the same manner as in Example 1, the above (1) to
The test of (3) was performed. The results are shown in Table 1.

Comparative Example 1 << Ink Composition >> Fast Cyan 2 (manufactured by Zeneca Dye Company) 3% by weight Diethylene glycol 25% by weight Glycerin 8% by weight Surfactant BT-7 (manufactured by Nikko Chemicals) 1% by weight Ion exchange Water 63% by weight The above ink composition was treated in the same manner as in Example 1 to prepare an ink, and then the above test was conducted. In the tests (2) and (3), non-ejection nozzles occurred. The results are shown in Table 1.

Comparative Example 2 << Ink Composition >> C.I. I. Direct Black 168 6.5% by weight Diethylene glycol 15% by weight Glycerin 5% by weight Surfactant ECTD-3NEX (manufactured by Nikko Chemicals) 1% by weight Ion-exchanged water 72.5% by weight The above ink composition was the same as in Example 1. When the above-mentioned test was performed after the ink was prepared by performing the above process, non-ejection nozzles were generated in the tests (2) and (3). The results are shown in Table 1.

Comparative Example 3 << Ink Composition >> C.I. I. Direct Red 227 4% by weight Diethylene glycol 5% by weight N-methylpyrrolidone 10% by weight Surfactant ECTD-3NEX (manufactured by Nikko Chemicals) 1% by weight Ion-exchanged water 80% by weight The above ink composition was prepared in the same manner as in Example 1. When the above test was performed after the ink was prepared by processing, non-ejection nozzles were generated in tests (2) and (3). The results are shown in Table 1.

Comparative Example 4 << Ink Composition >> C.I. I. Direct Black 168 4% by weight Diethylene glycol monomethyl ether 10% by weight Ethylene glycol 5% by weight Surfactant ECTD-3NEX (Nikko Chemicals) 1% by weight Ion-exchanged water 80% by weight The above ink composition was treated in the same manner as in Example 1. After the ink was prepared by using the above-mentioned method, the above-mentioned test was conducted. As a result, non-ejection nozzles were generated in the tests (2) and (3). The results are shown in Table 1.

[0031]

[Table 1]

[0032]

As described above, the cap covering the nozzle portion has a moisture permeability of 5 × 10 ⁻⁷ g at 20 ° C. and 60% RH.
/ Mm ² / hour or less, and contains a coloring agent, a wetting agent, and a surfactant that are dispersed or dissolved in water in the recording liquid, and has a viscosity of 5 mPa. By recording with ink of s or less, it is possible to prevent water evaporation of ink in the nozzle portion, and to suppress viscosity increase of ink even when water evaporates, thereby preventing ink clogging and long-term Good printing can be performed even when left unattended.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a front surface of a general print head.

FIG. 2 is a schematic diagram showing a relationship between a print head and a cap.

FIG. 3 is a vertical cross-sectional view showing an example of a print head and an ink cartridge in an inkjet recording device.

[Explanation of symbols]

1 print head 2 nozzles 3 caps Atmosphere opening of 4 caps 5 Cap suction port 6 Cartridge and head connection 7 cartridges 8 foam 9 Position where the cartridge's atmosphere opening port is provided 10 shaft

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Igarashi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Hirotaka Mochizuki 1-3-6 Nakamagome, Ota-ku, Tokyo In stock company Ricoh (72) Inventor Masayuki Oyano 1-3-6 Nakamagome, Ota-ku, Tokyo In-house company Ricoh (72) Takanori Tsuruki 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Inside the formula company Ricoh (72) Inventor Ikuko Tanaka 1-3-6 Nakamagome, Ota-ku, Tokyo Inside the formula company Ricoh (56) Reference JP-A-7-204182 (JP, A) JP-A-6-191052 (JP, A) JP 63-62739 (JP, A) JP 9-295404 (JP, A) JP 5-117561 (JP, A) JP 8-120204 (JP, A) Kaihei 7-62284 (JP, A) Special Japanese Patent Laid-Open No. 7-34018 (JP, A) Japanese Patent Laid-Open No. 2-173168 (JP, A) Japanese Patent Laid-Open No. 8-3499 (JP, A) Japanese Patent Laid-Open No. 9-291246 (JP, A) Japanese Patent Laid-Open No. 6-16984 (JP , A) JP-A-7-331141 (JP, A) JP-A-11-35861 (JP, A) JP-A-10-316911 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) B41J 2/165 B41J 2/01 B41M 5/00 C09D 11/02

Claims (5)

(57) [Claims] 1. A method for recording by recording an ink containing a colorant, a wetting agent and a surfactant dispersible or soluble in water in an ink jet recording apparatus having a nozzle portion covered with a cap, and recording the cap at 20 ° C. 60% R.I. H
The ink has a moisture permeability of 5 × 10 ⁻⁷ g / mm ² / hour or less, and the ink has a viscosity of 5 mPa. An ink jet recording method using an ink of s or less. 2. The ink jet recording method according to claim 1, wherein the total water content from the atmosphere opening port of the ink cartridge provided in the ink jet recording apparatus and the connection portion between the ink cartridge and the print head within the guaranteed period of use of the cartridge. An inkjet recording method, wherein an evaporation amount is 10% or less of an initial ink capacity filled in the cartridge. 3. The ink jet recording method according to claim 1, wherein the amount of the wetting agent contained in the ink is 10% by weight or more and 30% by weight or less, and the dye concentration is 6% by weight or less. And an inkjet recording method. 4. The ink jet recording method according to claim 3, wherein the wetting agent has a vapor pressure of 0.1 m at room temperature.
An ink jet recording method, wherein the ink jet recording method is mHg or less. 5. The ink jet recording method according to claim 3 or 4, wherein the wetting agent is a mixture of glycerol and diethylene glycol.