JP2002121435A - Refilling ink for ink-jet recording and method for refilling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a refilling ink not negatively affecting printed image qualities, discharge properties of ink and a head and to provide a method for refilling the same. SOLUTION: In this refilling ink which contains water, a water-soluble organic solvent and a colorant and is refilled into a used ink cartridge, at least one of water, a water-soluble organic solvent and a colorant is different from those of an initially filled ink and a surface tension γ(Refill), pH(Refill) and viscosity η(Refill) satisfy the relations (1) γ(Refill)/γ(Original)=0.8-1.1 (γ(Original) is the surface tension of the initially filled ink), (2) when pH(Original)>8, pH(Refill)>8 and pH(Original)-pH(Refill)=-2 to 2, when pH(Original)<=8, pH(Refill)<=8 and pH(Original)-pH(Refill)=-2 to 2 (pH(Original) is pH of the initially filled ink) and (3) η(Refill)/η(Original)=0.7-1.1 (η(Original) is viscosity of the initially filled ink).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refill ink for ink jet recording which is refilled in a used ink cartridge of an ink jet recording apparatus such as an ink jet printer represented by, for example, a thermal type or a piezo type, and a refill thereof. About the method.

[0002]

2. Description of the Related Art An ink jet recording apparatus such as an ink jet printer mainly discharges a liquid or a molten solid ink from a nozzle, a slit, a porous film or the like, and performs recording on paper, cloth, film or the like. . Ink jet recording devices are generally small and low cost,
Since high quality images can be obtained with little noise during printing, inkjet recording devices are mainly used in inkjet printers.
It is rapidly spreading from office to home use.

[0003] In recent years, however, the number of ink cartridges used per unit has increased along with the colorization and high image quality of ink jet printers, and most of them are disposable. The more waste the used ink cartridges are, the greater the amount. This is a flow that increases environmental destruction, which has become a serious problem, and also leads to an increase in printing cost for the user.

For this reason, it has been considered to refill a used ink cartridge with ink and reuse the ink cartridge. Refill inks that have been considered so far, as represented by JP-A-9-248919 or JP-A-11-228889, consider the affinity with the remaining initial filling ink, and This was a refilled ink having the same composition and the composition ratio was adjusted.

[0005] There are various other possible ways of reusing the ink cartridge. First, a method of refilling the ink directly with the used ink cartridge by the user himself or after cleaning with a cleaning liquid such as pure water is considered. When the manufacturer collects the ink cartridge, in addition to the above-described refilling method, it is possible to provide the user with a new-like ink cartridge by replacing, cleaning, and refilling some parts. Furthermore, when new technological advances were made in ink,
It is also conceivable to refill and resupply a high quality and low price ink of a new composition to a conventional cartridge. this is,
It is a very effective recycling method that can reduce the cost while maximizing the recycling of resources and provide the user with the latest and latest ink at that time.

[0006]

However, in any of the recycling methods described above, when the ink cartridge is refilled with the refilled ink, the reaction between the initially filled ink and the refilled ink causes deterioration and discoloration of the ink, thereby causing printing. This may adversely affect the image quality, adversely affect the dischargeability of the refill ink and the head.

The present invention has been made in view of the above circumstances. Even when refilling is performed using an ink having at least one kind of constituent material different from that of the initial filling ink, printing quality, ink dischargeability, and the like can be improved. An object of the present invention is to provide a refill ink for inkjet recording that does not adversely affect the head and a method for refilling the ink.

[0008]

Means for Solving the Problems As a result of diligent studies, the present inventors have found that the refilling ink for ink jet recording containing water, a water-soluble organic solvent and a coloring material has a surface tension, pH,
The inventors have found that the above object can be achieved by adjusting physical properties such as viscosity and the like with respect to the initially charged ink so as to satisfy a specific relationship, and have completed the present invention.

That is, the present invention relates to a refill ink for ink jet recording which contains water, a water-soluble organic solvent and a coloring material and is refilled into a used ink cartridge. At least one of the water, the water-soluble organic solvent and the colorant is different, and the surface tension γ _(Refill) , pH _(Refill) and viscosity η _(Refill)
Is a refill ink for inkjet recording characterized by satisfying the following relations (1) to (3). (1) Surface tension: γ _(Refill) / γ _(Original) = 0.8 to 1.1 (where γ _(Original) represents the surface tension of the initially filled ink) (2) pH: pH _(Original) > 8 , PH _(Refill) > 8 and pH _(Original) −pH _(Refill) =
−2 to 2, when pH _(Original) ≦ 8, pH _(Refill) ≦ 8 and pH _(Original) −pH _(Refill) =
2-2 (where pH _(Original) represents the pH of the initially filled ink) (3) Regarding viscosity, η _(Refill) / η _(Original) = 0.7-1.1 (where η _{(where Original)} indicates the viscosity of the initial filling ink)
Further, the present invention provides a used ink cartridge including a porous member as an ink holding member for holding ink,
A method for refilling the refill ink for inkjet recording, characterized by refilling the refill ink for inkjet recording.

According to the invention, even when the used ink cartridge is refilled with the refill ink for ink jet recording, the reaction between the initial refill ink and the refill ink remaining in the ink cartridge is sufficiently prevented. Thus, deterioration and discoloration of the ink in the used ink cartridge are sufficiently prevented. Further, when the used ink cartridge is refilled with the refill ink in this manner, even if at least one of the constituent materials is different from the initial fill ink, deterioration of the ink ejection property is sufficiently prevented, and the print head is prevented from being deteriorated. Negative effects (for example, corrosion or deterioration of the print head material) are sufficiently prevented.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

The refill ink for ink-jet recording of the present invention contains water, a water-soluble organic solvent and a coloring material, and further contains other components as required. Further, the initially charged ink initially charged is an ink in which at least one of the constituent materials has a different composition.

The refill ink for ink jet recording of the present invention has a surface tension γ _(Refill) , pH _(Refill) and viscosity η _(Refill) satisfying all of the following relationships (1) to (3). is there.

[0014] That is, the ink jet recording filling ink of the present invention, (1) a surface tension gamma for _{(Refill), γ (Refill)} / γ (Original) = 0.8~1.1 ( wherein, gamma _{(Original )} Represents the surface tension of the initially filled ink).

An ink cartridge often contains an ink holding member such as a urethane sponge for holding the ink, and is used for a sponge or the like which has a history of getting wet with the initially filled ink or pure water for washing. On the other hand, the refill ink needs to have better wettability. Therefore, the surface tension of the refilled ink needs to be substantially equal to or lower than that of the initially filled ink.
However, if the ratio of the surface tension of the refilled ink to the surface tension of the initial refilled ink is lower than 0.8, the affinity between the initial refilled ink and the refilled ink is deteriorated, and the deterioration or discoloration of the ink due to mixing may occur. Not suitable because it happens. In addition, the print image quality is likely to lower the image density and blur the image due to excessive penetration of the ink, which is different from the original print image quality using the initially filled ink. On the other hand, if the ratio of the surface tension of the refilled ink to the surface tension of the initial refilled ink is larger than 1.1, the penetration of the ink into the sponge becomes poor, or the ejection immediately after the refilled ink is filled into the ink cartridge. Therefore, it is necessary to frequently perform a forced suction operation of ink in a printer or the like.

In the present invention, the surface tension γ is 20
A value measured by a surface tensiometer (CBVP-A3 manufactured by Kyowa Interface Science Co., Ltd.) under an environment of 50 ° C. and 50% RH.

The ink jet recording recharger of the present invention
The filling ink is (2) pH, (i) pH_(Original)When> 8, pH_(Refill)> 8 and pH
_(Original)−pH_{(R efill)}Is -2 to 2, (ii) pH_(Original)≤8, pH_(Refill)≦ 8 and p
H_(Original)−pH _(Refill)Is -2 to 2, where pH_(Original)Represents the pH of the initially filled ink)
It satisfies the relationship of

In (i), pH _(Original) -pH
_{(Refill) In} the case of <−2, since the refill ink is strongly alkaline, corrosion and deterioration of the contact portion with the refill ink in the ink jet recording apparatus including the print head material may progress, and the pH _{( In} the case of _{(Origin )} −pH _(Refill) > 2, a sudden change in pH easily causes a reaction (particularly a colorant deposition reaction) between the initially filled ink and the refilled ink, which is not suitable. In (ii), the pH
_{When (Original)} −pH _(Refill) <−2, the dissolution stability of the coloring material in the ink deteriorates, and pH _(Original) −pH _(Refill)
In the case of> 2, the refill ink becomes strongly acidic, and it is difficult to handle at the time of refill such as damaging the skin, which is not suitable. The preferred range of the difference between the pH of the initially filled ink and the pH of the refilled ink is within ± 1.

The pH value referred to in the present invention refers to a value measured by a pH meter (EA940, manufactured by Orion) under the environment of 20 ° C. and 50% RH for the prepared ink.

Further, the refill ink for ink-jet recording of the present invention has the following properties. (3) Regarding viscosity, η _(Refill) / η _(Original) = 0.7 to 1.1 (where η _(Original) is the initial value ₎ (Representing the viscosity of the filled ink).

It is considered that the interior of the used ink cartridge at the time of refilling is in a state where a small amount of initially charged ink or pure water used at the time of cleaning remains. If the viscosity ratio exceeds 1.1, mixing with the remaining liquid in the ink cartridge causes excessive thickening, which deteriorates the ejection properties, slows the penetration into the medium, and slows down the drying of the ink. Further, the permeability of the ink to the sponge included in the ink cartridge is deteriorated.
On the other hand, when the viscosity ratio is less than 0.7, ink is likely to leak from the nozzles, making it impossible to perform normal ejection, or excessively penetrating compared to the initially filled ink, resulting in deterioration of image quality.

The viscosity η referred to in the present invention is 20 ° C., 50 ° C.
In an environment of% RH, a viscometer (METOT manufactured by Reomat Co., Ltd.)
LER RM260).

Further, in the refill ink for ink-jet recording of the present invention, the conductivity σ is also an important physical property indicating the concentration of the electrolyte substance in the ink, and σ _(Refill) / σ
_(Original) = 0.6 to 3.0 is preferred. When the ratio of the conductivity exceeds 3.0, the concentration of the electrolyte substance in the ink increases, and the dissolution stability of the ink component tends to deteriorate. In addition, particularly when the ink jet recording apparatus is a thermal ink jet system, a phenomenon called kogation in which thermally decomposed or aggregated ink components adhere to the heater is likely to occur, and the print drop amount, drop speed, image density, etc. Adverse effects tend to occur. On the other hand, when the above-mentioned conductivity ratio is less than 0.6, the difference in electrolyte concentration from the initial filling ink tends to be too large to affect print image quality.

The difference between the SP values of the refilled ink and the initially filled ink of the present invention is preferably within ± 3. Within this range, the compatibility when both inks are mixed is good. The difference between the SP values is more preferably within ± 2.

Surface tension γ of the refilled ink of the present invention
_(Refill) is preferably 25 to 50 mN / m.
When the surface tension γ _(Refill) is less than 25 mN / m, the image quality tends to be blurred or the ejection becomes unstable.
If it exceeds N / m, the drying of the print quality tends to be poor and the dot shape tends to be unstable.

The refill ink of the present invention has a pH _(Refill) of 6
-9 is preferable. If the pH _{( Refill)} exceeds this range, the head member tends to corrode.

Furthermore, the viscosity γ of the refilled ink of the present invention
_(Refill) is preferably 1.5 to 4.0 mPas. γ in the _(Refill) is less than 1.5mPas, the discharge becomes unstable dot tends not be stable, γ _(Refill)
Exceeds 4.0 mPas, nozzle clogging tends to occur.

The refilled ink of the present invention is different from at least one of the constituent materials of the initially filled ink. Maximum absorption wavelength λ _{max (Original)} of visible absorption spectrum of ink and maximum absorption wavelength λ _{max (Refill )} of visible absorption spectrum of refilled refilled ink
Λ _{max (Original)} −λ _{max (Refill)} is ± 1
Preferably it is within 5 nm. In this range, the color tone of the printed image does not change even by refilling, and an image with high color reproducibility can be obtained. Further, when there are a plurality of peaks in each of the visible absorption spectra of the initially filled ink and the refilled ink, the maximum absorption wavelength λ _(Original) (λ _{)
max (Original)} ) and the maximum absorption wavelength λ _(Refill) (λ _{max (Refill)}
Λ _(Original) −λ _(Refill) (λ
_{max (Original )} -λ _{max (} not including _Refill) ) is also ± 15
It is preferably within nm. In this case, even when a plurality of peaks are present in the visible absorption spectrum, the color tone of the printed image does not change by refilling, and an image with high color reproducibility can be obtained.

Note that λ _{max (Original)} −
Both λ _{max (Refill)} and λ _(Original) -λ _(Refill) are more preferably within ± 10 nm. In this range, the color tone of the printed image does not change by refilling,
An image with higher color reproducibility can be obtained.

The water used in the present invention is preferably distilled water, ion-exchanged water, pure water, or ultrapure water. Of these, there is no contamination with polyvalent cations or microorganisms, and the storage stability and eye resistance are high. From the viewpoint of clogging, ultrapure water is particularly preferably used.

The coloring material used in the refill ink of the present invention is preferably a dye, and more preferably an anionic water-soluble dye from the viewpoint of color reproducibility, safety and solubility stability. As the anionic water-soluble dye, direct dyes, food dyes, acid dyes, reactive dyes and the like can be used. Direct dyes such as CI Direct Black
-2, -4, -9, -11, -17, -19, -22, -32, -80, -151, -1
54, -168, -171, -194, -195; CI Direct Blue-
1, -2, -6, -8, -22, -34, -70, -71, -76, -78, -86,
-112, -142, -165, -199, -200, -201, -202, -203, -2
07, -218, -236, -287, -307; CI Direct Red-
1, -2, -4, -8, -9, -11, -13, -15, -20, -28, -31,-
33, -37, -39, -51, -59, -62, -63, -73, -75, -80,-
81, -83, -87, -90, -94, -95, -99, -101, -110, -18
9, -227; CI Direct Violet-1, -7, -9, -1
2, -35, -47, -51, -66, -93, -95, -98, -99, -100,-
106, -107; CI Direct Yellow-1, -2, -4, -8,-
11, -12, -26, -27, -28, -33, -34, -41, -44, -48,-
58, -86, -87, -88, -132, -142, -144, -173 are used, and as food dyes, for example, CI Food Black-1,
-2 is used.As the acid dye, for example, CI Acid Black-1, -2, -7, -16, -24, -26, -28, -31, -48, -5
2, -63, -107, -112, -118, -119, -121, -156, -172,
-194, -208; CI Acid Blue-1, -7, -9, -15, -2
2, -23, -27, -29, -40, -43, -55, -59, -62, -78, -8
0, -81, -83, -90, -102, -104, -111, -185, -249, -2
54; CI Acid Red-1, -4, -8, -13, -14, -15,-
18, -21, -26, -35, -37, -52, -110, -144, -180, -24
9, -257, -289; CI Acid Yellow-1, -3, -4,-
7, -11, -12, -13, -14, -18, -19, -23, -25, -34, -3
8, -41, -42, -44, -53, -55, -61, -71, -76, -78, -7
9, -122 are used, and as the reactive dye, for example, CI
Reactive Black-1, -4, -5, -8, -13, -14, -2
7, -30, -31, -34, -39, -43, -45, -46; CI Reactive Blue-3, -4, -5, -13, -14, -15, -18, -19 , -2
1, -25, -26, -27, -28, -38, -41, -49, -59, -71, -7
7, -104, -109, -113, -114, -120, -140, -160, -16
3, -171, -172, -194, -198, -203, -221, -222, -23
1; CI reactive red-1, -2, -3, -11, -12, -2
1, -22, -23, -24, -29, -31, -33, -35, -40, -43, -4
5, -49, -58, -74, -76, -101, -106, -120, -141, -14
7, -152, -159, -180, -194, -195, -198, -222, -22
7, -250; CI Reactive Yellow-1, -2, -3, -4,-
7, -15, -17, -18, -22, -23, -24, -25, -27, -37, -4
2, -44, -46, -77, -81, -84, -85, -86, -105, -116,
-125, -135, -145, -154, -160, -167 and the like are used, but direct dyes, food dyes, acid dyes, and reactive dyes are not limited thereto. These dyes are
Although it can be used alone, two or more kinds may be mixed so that the visible light absorption spectrum wavelength of the refill ink satisfies the above-mentioned wavelength range with respect to the visible light absorption spectrum wavelength of the initially filled ink.

The content of the above-mentioned dye is preferably in the range of 0.1 to 10.0% by weight in the refilled ink, though it depends on the coloring property of the dye. When the content of the dye is less than 0.1% by weight, the image density tends to decrease, and when the content of the dye exceeds 10.0% by weight, the dye tends to precipitate. The content of the dye is more preferably from 0.3 to 8% by weight from the viewpoint of the solubility stability of the dye.

The water-soluble organic solvent used in the present invention is at least one selected from polyhydric alcohols, polyalkylene glycols, glycol ethers and polar solvents. Two
When the number is more than the seed, the moisturizing property of the ink and the solubility of the coloring material are improved, and the penetration into a porous member such as a urethane sponge at the time of refilling is further improved. In addition, clogging resistance and ejection stability of the ink jet recording ink can be maintained, and aggregation and precipitation of the coloring material can be prevented even during long-term storage. Among them, glycerin, diethylene glycol, 2,2′-thiodiethanol, and sulfolane are particularly preferable from the viewpoint of dissolution stability of the coloring material. Further, from the viewpoint of the permeability of the ink for ink jet recording into paper and the solubility of the coloring material, glycol ether is preferable, and diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether are particularly preferable.

The polyhydric alcohols and polyalkylene glycols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, 1,5-pentanediol, glycerin, 2,2'-thiodiethanol, triethanol Amines and the like can be suitably used.

As the glycol ether, for example, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether and the like can be preferably used.

The polar solvent refers to a solvent having a large dipole moment or a large dielectric constant of the solvent. Examples of the polar solvent include N, N-dimethylformamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, and cyclohexyl. Pyrrolidone, dimethyl sulfoxide, sulfolane and the like can be suitably used. Among the polar solvents, cyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, and sulfolane are particularly preferable from the viewpoint of the solubility stability of the coloring material.

In addition to these solvents, alcohols such as ethanol, isopropanol, butanol and benzyl alcohol, and alkanolamines such as monoethanolamine, diethanolamine and triethanolamine may be added.

In the present invention, the content of the water-soluble organic solvent in the refill ink for ink jet recording is preferably 3 to 40% by weight. When the content of the water-soluble organic solvent is less than 3% by weight, the refill ink for ink-jet recording tends to dry and precipitate, and tends to cause ejection failure such as nozzle clogging, while exceeding 40% by weight. In this case, the fixability of the ink to the paper is poor, and the viscosity of the ink is increased, so that a discharge failure is likely to occur. The content of the water-soluble organic solvent is more preferably 10.0 to 35.0% by weight in view of the balance between nozzle clogging prevention and ejection stability.

The refill ink of the present invention may contain components other than the above-mentioned water, water-soluble organic solvent and coloring material, and these components may be appropriately selected according to the purpose without any particular limitation. it can.

For example, a surfactant may be used as another component. When a surfactant is contained in the ink, the surfactant not only promotes the permeability of the ink for ink jet recording to paper, but also causes the interaction between the surfactant and the colorant molecules, thereby increasing the color. The wettability of the material to the paper fiber is improved, so that deterioration of image quality and color tone due to color unevenness and the like are prevented.

The surfactant used in the present invention is at least one selected from a nonionic surfactant, an anionic surfactant and an amphoteric surfactant.

Examples of the nonionic surfactant include, for example,
Polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, etc., polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene Polyoxypropylene block copolymers, ethylene oxide adducts of acetylene glycol, ethylene oxide adducts of glycerin, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylolamides and the like can be used.

Examples of the anionic surfactant include, for example,
Alkyl benzene sulfonate, alkyl naphthalene sulfonate, formalin condensate of alkyl naphthalene sulfonate, higher fatty acid salt, higher fatty acid ester sulfate, higher fatty acid ester sulfonate, higher alcohol ether sulfate, and Sulfonates, alkylcarboxylates of higher alkylsulfonamides, sulfosuccinates, ester salts thereof and the like can be used.

As the amphoteric surfactant, for example, betaine, sulfobetaine, sulfate betaine, imidazolidone betaine and the like can be used.

In the present invention, among these surfactants, a nonionic surfactant which does not easily interact with ions of a coloring material or ions of other components is preferable, and in terms of thermal stability and purity. Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene-polyoxypropylene block copolymer are more preferred.

In the present invention, the content of the surfactant in the refill ink for inkjet recording is 0.00
It is preferably from 5 to 5% by weight, more preferably from 0.01 to 2% by weight. If the ratio is outside the above range, filling tends to be difficult, for example, bubbles are generated during refilling.

Next, the method for refilling the refill ink according to the present invention will be described.

The used ink cartridge used in the present invention is an ink cartridge in which a printed image is blurred when printed. The used ink cartridge used in the present invention usually contains a porous member such as a urethane sponge as an ink holding member.
In addition, the used ink cartridge usually has a state in which a small amount of the initially filled ink or pure water used at the time of cleaning remains.

In the refilling method of the present invention, the used ink cartridge is refilled with the refilled ink. As the refill ink, the refill ink described above, i.e., water, a refill ink containing a water-soluble organic solvent and a coloring material, the water, the water-soluble organic solvent and the A refill ink is used in which at least one of the color materials is different and the surface tension γ _(Refill) , pH _(Refill) and viscosity η _(Refill) satisfy the following relationships (1) to (3). (1) surface tension (in the formula, gamma _(Original) represents the surface tension of the initial filling _{ink) γ (Refill) / γ (} Original) = 0.8~1.1 (2) for pH, pH _{( Original)} > 8, pH _(Refill) > 8 and pH _(Original) −pH _(Refill) =
−2 to 2, when pH _(Original) ≦ 8, pH _(Refill) ≦ 8 and pH _(Original) −pH _(Refill) =
−2 to 2 (where pH _(Original) represents the pH of the initially filled ink) (3) Regarding viscosity, η _(Refill) / η _(Original) = 0.7 to 1.1 (where η _(Original) is the initial value ₎ When the used ink cartridge is refilled with such a refilled ink, the reaction between the initially filled ink and the refilled ink remaining in the ink cartridge in a small amount is sufficiently prevented, and the used ink cartridge is used. Deterioration and discoloration of the ink in the ink cartridge are sufficiently prevented, and adverse effects on print image quality are sufficiently prevented. Further, when the used ink cartridge is refilled with the refilled ink in this manner, deterioration of the dischargeability of the refilled ink is sufficiently prevented, and adverse effects on the print head (for example, corrosion and deterioration of the print head material) are sufficiently reduced. Is prevented.

[0050]

EXAMPLES Hereinafter, the content of the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.

Examples 1 to 4 and Comparative Examples 1 to 4 (Preparation of Ink) A water-soluble dye, a water-soluble organic solvent, a surfactant and water were sufficiently mixed and dissolved in the proportions shown in Table 1 below, and the following Table 1 was obtained. After performing pH adjustment using the pH adjuster shown in (1), pressure filtration was performed using a 0.45 μm filter to produce refilled inks and initial filled inks 1 to 4 of Examples 1 to 4 and Comparative Examples 1 to 4. did. The unit of the numerical values shown in Table 1 is% by weight.

[0052]

[Table 1]

(Measurement of Physical Properties of Ink) Refilled inks and initial filled inks 1 to 4 of Examples 1 to 4 and Comparative Examples 1 to 4
Were measured for physical properties such as pH, surface tension, viscosity, and maximum and maximum absorption wavelength values. Table 2 shows the results.

[0054]

[Table 2]

The physical properties of pH, surface tension, viscosity and maximum and maximum absorption wavelengths were measured as follows. <PH> The pH was measured using a pH meter (EA940 manufactured by Orion) in an environment of 20 ° C. and 50% RH. <Surface Tension> The surface tension was measured using a surface tension meter (CBVP-A manufactured by Kyowa Interface Science Co., Ltd.) in an environment of 20 ° C. and 50% RH.
It measured using 3). <Viscosity> The viscosity was measured under an environment of 20 ° C. and 50% RH using a viscometer (METLER RM26 manufactured by Reomat).
0). <Maximum and maximum absorption wavelength values> Examples 1 to 4 and Comparative Example 1
To 4 and the initial filling inks 1 to 4 are each diluted 1000 times with pure water, put into a quartz cell having a thickness of 10 mm, and put the quartz cell into a self-recording spectrophotometer (UV).
-2500PC: manufactured by Shimadzu Corporation) and the absorbance was measured. Visible absorption spectrum (wavelength range; 300 nm
８００800 nm), the wavelength value at which the absorption was maximum was defined as the maximum absorption wavelength. When there are a plurality of maximum values, the wavelength value at which the absorbance shows the highest value is defined as the maximum absorption wavelength. In Table 2, the maximum absorption wavelength value is indicated by “*”.
Is attached.

(Refilling of Ink) An ink cartridge already filled with the initial filling ink of each color shown in Table 1 is set in a prototype thermal ink jet printer, and printed until a solid image is blurred. The ink was exhausted. The ink cartridge in this state was refilled with the same color ink of the example or comparative example in Table 1. The used ink cartridge contained a urethane sponge as an ink holding member, and the refilling of the refilling ink was performed by using a communication hole of the ink cartridge and injecting with a syringe.

(Observation of Penetration of Ink into Ink Holding Member During Refilling) When the ink cartridge contains an ink holding member such as a urethane sponge, the refilled ink is likely to penetrate into the ink holding member. is important. Then, the permeability of each of the refilled inks of Examples 1 to 4 and Comparative Examples 1 to 4 into the ink holding member was examined. The permeability of the ink into the ink holding member was determined by dropping the refilled inks of Examples 1 to 4 and Comparative Examples 1 to 4 of Table 1 onto a urethane sponge of the same material as that contained in the ink cartridge with a dropper. The test was conducted by measuring the permeation time of the ink at that time. Table 2 shows the results. In Table 2, when the ink penetrates into the urethane sponge in less than 1 second, the permeability is evaluated as good and is indicated by “「 ”, and when it takes more than 1 second, the permeability is poor. And evaluated as “×”.

(Evaluation of Ink Dischargeability and Print Quality) In order to evaluate the ink dischargeability and the print quality of the refilled ink, one of Examples 1-4 and Comparative Examples 1-4 was refilled. Each of the ink cartridges was tested for dischargeability after refilling, clogging resistance, and change in hue (color difference) between the initially filled ink and the refilled ink. In this test, a prototype inkjet recording head (constituting material is made of silicon, polyimide, and epoxy)
And a thermal inkjet printer equipped with the same. The driving condition of the recording head is a driving voltage of 3
The test was performed at 5 V, a resistance value of the heating resistor of 180Ω, and a frequency of 7 kHz. Among the driving conditions of the recording head, the driving pulse for printing discharge and the driving pulse for preliminary discharge with respect to the recording signal were performed under the following conditions. That is, the preliminary ejection is performed when the printing ejection is 1 ×
When the number of pulses exceeded 10 ^{7, the} measurement was performed with 1 × 10 ⁵ pulses.

(Ejection properties immediately after refilling) In order to evaluate the ejection properties of the refilled ink, Examples 1-4 and Comparative Examples 1-4
20 ° C, 50% RH using a prototype 800 dpi thermal inkjet printer using each refill ink
The discharge test was performed under the following environment. The ink drop amount at this time was 8 to 10 ng in each case. Table 2 shows the results. In Table 2, when the number of forcible ink suction (head cleaning) operations by the printer machine is 1 or less, the ink ejection property is good and it is determined that there is no practical problem. "O" is displayed, and if the forced ink suction (head cleaning) operation by the printer machine is 2 or more and less than 5 times, it is judged that there is a practical problem in the ink dischargeability and "△" is displayed. And forcible ink suction by the printer machine (head cleaning)
When the operation was performed 5 times or more, it was judged that there was a practical problem in the ink dischargeability, and "x" was displayed.

(Evaluation of clogging resistance) In order to evaluate the dischargeability of the refilled ink refilled into the ink cartridge,
The difficulty of clogging of the refill ink, that is, the clogging resistance was evaluated as follows. That is, Examples 1 to 4 and Comparative Example 1
Using each of the refilled inks Nos. 1 to 4, a prototype thermal ink jet printer with a resolution of 800 dpi was used.
In an environment of% RH, the ink cartridge was left for a predetermined time in a state where the discharge port of the ink cartridge was opened (that is, a state where the cap was opened), and then a discharge test was performed. Table 2 shows the results. In addition,
The ink drop amount at this time was 8 to 10 ng in each case. In Table 2, the ink cartridge is
If discharge is possible even after standing for 300 seconds or more, it is judged that dischargeability is not practically problematic, and "O" is displayed.
If it is possible to discharge even if left for 80 seconds or more, but if it is impossible to discharge after 300 seconds or more, it is judged that the dischargeability is not sufficient and there is a practical problem, and "△" is displayed.
If the time is shorter than seconds, the ink can be discharged even if left for a while, but if the liquid cannot be discharged if the liquid is left for 180 seconds or more, the dischargeability is poor and it is judged that there is a considerable problem in practical use.

(Color Difference between Initially Filled Ink and Refilled Ink)
In order to check whether the print image quality when using the refilled inks of Examples 1 to 4 and Comparative Examples 1 to 4 is different from the case where the initially filled ink is used, the initial filling ink is set as follows. And the color difference between the refilled inks.

That is, first, Examples 1 to 4 and Comparative Examples 1 to 4
Glossy paper A for inkjet printers (75-degree specular gloss: 82%) and glossy paper B for ink-jet printers (75-degree specular gloss), which were produced using the refilled inks of : 64%). The same printing was performed for the initial filling inks 1 to 4, and the initial filling ink and Examples 1 to 4 and the initial filling ink and Comparative Examples 1 to 4 were used.
4 and the color difference ΔE ^* was calculated. Table 2 shows the results. The calculation of ΔE ^{* is} as follows: ΔE ^* = ｛(L ₁ ^* −L ₂ ^* ) ² + (a ₁ ^* −a ₂ ^* ) ² + (b ₁ ^*
−b ₂ ^* ) ² ｝ ^1/2 (where the subscript 1 represents the initial filling ink and the subscript 2 represents the refilling ink), and the values of L, a, and b are determined by the Macbeth densitometer (“X− Rite 938 ”(X-Rite, Inc. (X
-Rite, Inc. The values measured in the above) were used.
The color difference was evaluated as follows according to the value of ΔE ^* . That is, when the value of ΔE ^* is 0 ≦ ΔE ^* <10, a change in hue can hardly be recognized by the naked eye,
Since no change was observed in comparison with the print image quality when the initial filling ink was used, "O" was displayed. Also, ΔE ^*
Is 10 ≦ ΔE ^* <20, the change in hue can be recognized by the naked eye, and the print quality has changed as compared with the case where the initial filling ink is used. Further, when the value of Delta] E ^* is 20 ≦ Delta] E ^* is, since the hue change could be clearly identified with the naked eye, and display a "×".

(Continuous Ejection Test (Occurrence of Heater Failure)) In the prototype ink jet printer used for evaluating the ink ejection properties and print image quality, the recording head drive conditions were the same as those described above (drive voltage 35 V). A continuous ejection test was performed up to 1 × 10 ⁸ printing pulses at a heating resistor resistance of 180Ω and a frequency of 7 kHz, and the occurrence of heater failure was observed and evaluated according to the following criteria.

…: No occurrence ×: Occurrence From the above results, the refilled ink of the present invention has excellent permeability to the ink holding member, good dischargeability, and print quality that is lower than that of the initially filled ink. It turned out that it hardly changed. It was also found that the refilled ink of the present invention did not adversely affect the print head.

[0065]

As described above, according to the refill ink for ink jet recording and the method for refilling the same according to the present invention,
Even when refilling is performed using an ink having at least one kind of constituent material different from the initial filling ink, there is no adverse effect on print image quality, ink dischargeability, and head.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiromi Nagai 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Takeshi Hashimoto 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Reference) 2C056 FC01 FC02 KC01 KC11 2H086 BA60 BA61 4J039 BC07 BC09 BC13 BC35 BC36 BC50 BC54 BC55 BE03 BE04 BE06 BE12 CA03 EA15 EA16 EA17 EA19 EA21 EA41 EA42 EA44 GA24

Claims (2)

[Claims] 1. It contains water, a water-soluble organic solvent and a coloring material,
In a refill ink for ink jet recording to be refilled into a used ink cartridge, at least one of the water, the water-soluble organic solvent, and the coloring material is different from the initially charged ink initially filled, and Tension γ _(Refill) , pH _(Refill) and viscosity η
_A refill ink for inkjet recording, wherein _(Refill) satisfies the following relations (1) to (3). (1) Surface tension: γ _(Refill) / γ _(Original) = 0.8 to 1.1 (where γ _(Original) represents the surface tension of the initially filled ink) (2) pH: pH _(Original) > 8 , PH _(Refill) > 8 and pH _(Original) −pH _(Refill) =
−2 to 2, when pH _(Original) ≦ 8, pH _(Refill) ≦ 8 and pH _(Original) −pH _(Refill) =
−2 to 2 (where pH _(Original) represents the pH of the initially filled ink) (3) Regarding viscosity, η _(Refill) / η _(Original) = 0.7 to 1.1 (where η _(Original) is the initial value ₎ Represents the viscosity of the filled ink) 2. A refill ink for ink jet recording according to claim 1, wherein a used ink cartridge containing a porous member as an ink holding member for holding ink is refilled with the refill ink for ink jet recording according to claim 1. How to refill the filling ink.