JPH1120192A - Ink-holding body and ink cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink-holding body which can prevent tinting of ink by adding a composition essentially consisting of polyether polyol and polyisocyanate and a specific organic metallic compound as a catalyst, and further mixing and foaming a foaming agent. SOLUTION: A composition essentially consisting of polyether polyol and polyisocyanate and one selected as a catalyst from a group of organic metallic compounds expressed by a formula I and/or a formula II are used, and moreover a foaming agent is mixed and foamed, thereby obtaining an ink-holding body of polyurethane foam. In the formula I, (n) is a natural number 1-4, R1 is an alkyl group, and Me represents K, Na, Ca, Fe, Mg, Hg, Ni, Pb, Co, Zn, Cr, Al, Sn, V, Ti. In the formula II, R2 , R3 are independent or the same alkyl groups, Me is Zn, Si, Sn, Pb, Sb. in the formula I or II, preferably, Me is Sn(II).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink holding member for holding an ink composition, and an ink cartridge serving as an ink supply member in an ink jet recording apparatus filled with the ink holding member.

[0002]

2. Description of the Related Art In general, an ink cartridge serving as an ink supply unit in an ink jet recording apparatus compresses and stores a foam in order to uniformly hold a liquid ink and to stably supply the ink. As a holding member, a holding member which is used by impregnating the ink is often used.

Conventionally, a foam serving as an ink holding member used in an ink cartridge is disclosed in Japanese Patent Application Laid-Open No. Sho 64-26.
No. 452, and the like, those using reticulated and felted typical polyether-type polyurethane foams, and JP-A-7-32613.
In general, urethane foams are often used, for example, in Japanese Patent Application Laid-Open Publication No. H08-157, the use of a specific heat-fusible polyurethane foam is described.

However, in these urethane foams, many non-volatile impurities such as catalysts and unreacted substances used in the production of the urethane foam remain,
Dissolution or dispersion in the ink when used in an ink cartridge may contaminate the ink or affect the fluid properties of the ink. In particular, when used in an ink jet recording apparatus, the ink in which the non-volatile impurities are dissolved may invade the head member when left for a long time with the print head filled, or the non-volatile impurities once dissolved in the ink may be damaged. Re-precipitation at the nozzle or the like may affect the ink ejection characteristics. Thus, Japanese Patent Application Laid-Open No. 64-26452 describes a method for determining the cleanliness of urethane foam, and Japanese Patent Application Laid-Open No. 64-26453 describes an apparatus for cleaning urethane foam.

In the former, the amount of non-volatile impurities contained in the urethane foam after washing is reduced to 0.2 parts by weight or less with respect to the urethane foam, and the surface tension of the ink immersed in the urethane foam is 40 mN / m. It must be greater or the surface tension drop must be less than 7 mN / m, the latter describing a recirculating, closed-loop automatic contaminant removal system using Freon 113 as the cleaning solvent. . In this case, a Freon-based solvent called Freon 113 is used as a cleaning solvent, which is extremely volatile and is harmful to the natural environment. There is a problem that the ink has poor compatibility with the ink used as a solvent, and if the ink remains on the urethane foam, it may affect printing characteristics.

[0006] Regarding the former, the description of the fluctuation of the surface tension value can be used as a guideline as an evaluation method for determining whether or not the prepared urethane foam can be used for an ink cartridge. This is not a means for obtaining a foam which is essentially not affected by nonvolatile impurities.

[0007] In addition, Japanese Patent Application Laid-Open No. 7-32605 discloses that when an ink containing acetylene glycol is used, the appropriate use range of the ink is widened by previously washing with an aqueous acetylene glycol solution. Is for the purpose of preventing the print quality from deteriorating, and has no effect on nonvolatile impurities contained in the foam.

On the other hand, as a urethane foam for preventing ink contamination, Japanese Patent Application Laid-Open No. 5-38816 discloses that a polymer polyol grafted with styrene and / or acrylonitrile is used in an amount of 20 parts by weight or more of the total polyol and the number of cells is reduced. By using a urethane foam of 20 pieces / inch or more as an ink holder, deterioration of the urethane foam itself due to ink is suppressed, and stabilization of ink holding and supply is provided. However, in this case, although the ink contamination due to the dissolution or decomposition of the urethane foam itself can be reduced, there is almost no effect on the ink contamination due to the non-volatile impurities remaining inside.

[0009]

SUMMARY OF THE INVENTION The present invention relates to ink contamination caused by non-volatile impurities in the conventional ink holder made of urethane foam, and the ink generated when used in an ink cartridge for an ink jet recording apparatus. An object of the present invention is to provide an ink cartridge capable of obtaining a good printed image by eliminating a problem such as an influence on a discharge characteristic of the ink, and to provide an ink holding body for preventing ink contamination due to a nonvolatile impurity required for the purpose. It is to do.

[0010]

Accordingly, the ink carrier of the present invention is an ink carrier for receiving an ink comprising at least a dye, glycols, glycol ethers and water, and comprises at least a polyether polyol and a polyether polyol. 0.01% of at least one selected from the group consisting of organometallic compounds represented by the following (I) and / or (II) as a catalyst:
It is characterized by comprising a urethane foam obtained by mixing and foaming a foaming agent with about 0.1 part by weight.

[0011]

Embedded image

More preferably, in the above (I) and / or (II), Me is Sn (II), particularly preferably, in (I), Sn (II) octylate. It is characterized by.

Further, the ink cartridge of the present invention is characterized in that it is filled with an ink holder made of the urethane foam.

The main non-volatile impurities generated in the production of urethane foam are unreacted polyether polyols and polyisocyanates, and catalysts. In other words, reducing these leads to solving the problem, but these are mutually contradictory.If the catalyst is small, the reaction does not proceed easily, and if the catalyst is increased, the catalyst residue remaining in the urethane foam increases. Become. Therefore,
The issue is how to enhance the reaction with a small amount of catalyst.

In the present invention, the catalyst used includes:
It is preferable to use at least one selected from the group consisting of the organometallic compounds represented by the above (I) and / or (II). These are general and useful catalysts in the production of polyurethane foam, and are widely and generally used in the range of about 0.2 to 1 part by weight in consideration of the reaction rate and the like. However, when used in an ink cartridge of an ink jet recording apparatus as an ink carrier, particularly an ink carrier for holding an ink using a dye as a coloring material and water as a solvent, the recording apparatus may be used for a long time. When left unused, the insoluble organometallic compound adhered as foreign matter to the inner wall of the nozzle of the print head, and the ink ejection characteristics were greatly impaired. Although the clear cause is unknown, it is presumed that the metal is contained as an ion in the dye, and it is generated by interaction or reaction with these.

Therefore, in the present invention, the above (I) and / or
Alternatively, the amount of the catalyst comprising at least one selected from the group consisting of the organometallic compounds represented by (II) is preferably in the range of 0.01 to 0.1 part by weight.
If the amount exceeds 0.1 parts by weight, insoluble foreign matters adhere to the inside of the nozzles of the print head as described above, which causes a deterioration in the ink ejection characteristics. If the amount is less than 0.01 part by weight, the reaction for producing the urethane foam does not proceed, and a large amount of unreacted polyether polyol and polyisocyanate remain, and conversely, these dissolve in the ink and cause ink contamination, which is not preferable. .

In the present invention, among the metal elements in the ink finally contained in the ink cartridge, the content of the metal element corresponding to Me shown in the above (I) and / or (II) is 2.5 × 10 5 ^-6 mol / g or less is preferable. Within this range, even when the inkjet recording is left unused for a long period of time, the above-described foreign matter does not occur on the inner wall of the nozzle, and stable ejection characteristics can be maintained.

In the present invention, the organometallic compound used as the catalyst includes ink safety and storage stability,
In consideration of matching with a material constituting a print head, Me is more preferably Sn (II), and particularly preferably Sn (II) octylate.

In the present invention, the catalyst may be used alone, but may be used together with a tertiary amine such as triethylamine, triethylenediamine, N-methylmorpholine or the like, if necessary.

In the present invention, as the ink holding member,
Polyurethane foam obtained by reacting a polyether polyol and a polyisocyanate at least in the presence of the catalyst and a foaming agent, as the polyether polyol, widely known publicly known polyether polyols Can be used. As the polyether polyol, a molecular weight of about 1,000 to 1,000
At 0, it can be obtained by reacting a polyhydroxy compound such as propylene glycol, ethylene glycol, glycerin, triethanolamine, ethylenediamine and the like with ethylene oxide, propylene oxide and the like, and specific examples include glycerin-based polypropylene glycol and the like. I can do things. In general, polyester polyols and the like may be used as the polyol used for producing urethane foam.However, in the present invention, since the urethane foam is in direct contact with the ink, the ink deteriorates even when the ink is alkaline or acidic. The polyether polyol having a small amount is more preferable.

As the polyisocyanate, there can be used an aromatic polyisocyanate having two or more isocyanate groups in the same molecule, an aliphatic polyisocyanate, or a modified product thereof. , Diphenylmethane diisocyanate, xylylene diisocyanate and the like.

The foaming agents used in the present invention include water, air, nitrogen,
Pentane, methylene chloride, nitroalkane and the like can be used. In addition, in the production of urethane foam, a foam stabilizer such as silicone oil or a cell open agent such as polyether siloxane may be used as necessary.

In the present invention, the produced urethane foam may be used as it is, but for the purpose of enhancing the ink holding power, a film formed between cells using a mixed gas of oxygen and hydrogen or the like is used. The substance may be used after being subjected to a solution treatment.

In the ink holding member of the present invention, the number of cells is preferably in the range of 20 to 60 cells / inch from the viewpoint of ink holding. If the number of cells is too large, the amount of ink that can be held decreases, and the capillary effect of the cells works strongly, so that the effective ink amount decreases, which is not preferable. Conversely, if the number of cells is too small, capillary action does not work as it is, and even if the ink holder is compressed and used, the size of the cells in the ink holder is difficult to be uniform, and the ink is uniformly distributed in the foam. Is difficult to maintain, and neither is preferable.

The ink cartridge of the present invention is filled with the ink holder manufactured according to the above-mentioned contents. At this time, if necessary, the foam is optionally compressed to control the density. Can be used. In particular, the compression ratio of the ink retainer roughly correlates with the number of cells of the urethane foam. When the number of cells is small, the compression ratio is high, and when the number is large, the compression ratio is low. The shape and the characteristics of the ink, the flow path structure of the print head, the position of the nozzle portion and the joining position of the ink cartridge, and the like are appropriately determined by various parameters. It is preferably used in a volume ratio of 1/1 to 1/10 with respect to the volume of the ink cartridge, and more preferably about 1/2 to 1/5.

The ink held in the ink holder or filled in the ink cartridge used in the present invention includes at least a dye as a coloring material, glycols as a wetting agent, glycol ethers as a penetrating agent,
And at least consisting of water as the main solvent,
A water-based ink can be used.

As the dye, generally known direct dyes, acid dyes, basic dyes and the like which are easily soluble in water can be widely used. Although it is possible to use a dispersion type dye or pigment as a coloring material, since these are only dispersed in the ink, urethane foam having a large number of cells is used by approaching the ink holder. It is not preferable to use the ink holding member as a main coloring material because of the possibility of adsorption.

As the glycols, those which can be widely used in an ink jet recording apparatus, specifically, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and the like can be used. Glycol ethers can also be widely used in inkjet recording devices,
Specifically, ethylene glycol monoethyl ether,
Diethylene glycol monobutyl ether, diethylene glycol methyl ethyl ether, triethylene glycol monobutyl ether, and the like can be used. In addition, an ink to which a surfactant such as acetylene glycol, a preservative, a rust inhibitor, a pH adjuster, or the like is added as necessary may be used.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples.

(1) Manufacture of Ink Holder In Examples 1 to 3 and Comparative Examples 1 and 2, all components except for isocyanate were mixed and stirred at the components shown in Table 1, and then the isocyanate was added thereto. In addition, the mixture was further stirred, placed in an arbitrary container, and heated at 140 ° C. for 10 minutes to foam, thereby obtaining a predetermined urethane foam.

The urethane foam is 30 mm × 30
After being cut to a size of 20 mm × 20 mm, it is placed in a closed container, and the inside of the container is made to have an oxygen: hydrogen ratio of about 1: 2 and a pressure of 9.8 × 10 ⁴ Pa.
And the mixture was ignited to perform a solution film treatment.

[0032]

[Table 1]

(2) Production of Ink Composition After mixing and stirring the components shown in Table 2, these were filtered through a 1.0 μm membrane filter to obtain the ink compositions shown in the table.

[0034]

[Table 2]

(3) Manufacture of Ink Cartridge The ink holder manufactured in the above (1) is used for the magenta chamber 4 and the cyan chamber 5 of the lower case 2 (material: polypropylene) shown in FIGS. , Yellow chamber 6 by compression filling, and then upper case 3 (material: polypropylene)
Was heat-welded to the lower case 2 to obtain the form of the ink cartridge 1. Thereafter, the ink prepared in (2) is gently injected into each of the ink holders through the ventilation holes 7 to 9 with a syringe by 15 g for each ink holder according to the description in the lower part of Table 1, and the ink is injected into the holder. The mixture was allowed to stand at room temperature for one day to obtain a desired ink cartridge.

(4) Test The ink cartridge manufactured in the above (3) was attached to a recording apparatus, and the following tests were performed. The ink jet recording apparatus used was MJ-510C and MJ-510C (both trade names of an ink jet printer manufactured by Seiko Epson Corporation), and a color head was used as a recording head. The print pattern used in the print test was a self-test that was standardly installed in the inkjet recording apparatus.

Print test immediately after installation 40 ° C.1 with the print head in the normal rest position
Print test after leaving for 4 months Print test after leaving for 2 months at 40 ° C Print test after leaving the print head from the printer body and leaving it for 1 week at 40 ° C naked without using the head storage case Printing after leaving for 2 weeks at 40 ° C Test The results of the printing test after leaving at 40 ° C for one month are shown in Table 3 below.

[0038]

[Table 3]

From the results of the above examples, it was found that a composition containing at least polyether polyol and polyisocyanate as main components was used as an ink carrier for receiving an ink composed of at least a dye, glycols, glycol ethers and water. , As a catalyst of formula (I) and / or (I
By using urethane foam obtained by mixing and foaming at least one selected from the group consisting of organometallic compounds represented by I) with a foaming agent and 0.01 to 0.1 part by weight, non-volatile impurities It is possible to prevent the influence of ink contamination, and use the ink holder in an ink cartridge, and use M in the group consisting of the organometallic compounds represented by the formulas (I) and / or (II) in the ink.
The content of the metal element corresponding to e is 2.5 × 10 ⁻⁶ mo
By setting the ratio to 1 / g or less, it is possible to provide a normal printed image without affecting the ink ejection characteristics of the print head even after the ink jet recording apparatus has not been used for a long time.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an ink cartridge obtained by the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink cartridge 2 Lower case 3 Upper case 4 Magenta room 5 Cyan room 6 Yellow room 7-9 Vent hole

Claims (5)

[Claims] 1. An ink carrier for receiving an ink composition comprising at least a dye, a glycol, a glycol ether, and water, wherein the composition mainly comprises at least a polyether polyol and a polyisocyanate, and a catalyst. Urethane foam obtained by mixing and foaming 0.01 to 0.1 parts by weight of at least one selected from the group consisting of organometallic compounds represented by the following (I) and / or (II): An ink carrier comprising: Embedded image 2. The ink carrier according to claim 1, wherein in the catalyst (I) and / or (II), Me is Sn (II). 3. The catalyst (I) is an octylic acid Sn (I
3. The ink carrier according to claim 2, which is I). 4. An ink cartridge for use in an ink jet recording apparatus, wherein the ink carrier and the ink composition according to claim 1 are filled therein. 5. A metal element represented by the catalyst (I) and / or (II) among metal elements contained in the ink composition.
e of 2.5 × 10 ⁻⁶ mol /
The ink cartridge according to claim 4, wherein the value is equal to or less than g.