Patent Application
20110267408
This application claims priority from Japanese Patent Application No. 2010-105874 filed on Apr. 30, 2010. The entire subject matter of the Japanese Patent Applications is incorporated herein by reference.
In ink-jet recording, an ink cartridge containing an ink is used. There is a case in which the ink cartridge is provided with a remaining ink detecting portion detecting the amount of remaining ink. The remaining ink detecting portion detects the amount of remaining ink on the basis of whether or not light is transmitted therethrough. On the other hand, there is a case in which a water-based ink of higher penetration (wettability) relative to a recording medium is used for the purpose of improving the quality of a recorded image in ink-jet recording. However, when the water-based ink of higher penetration is contained in an ink cartridge, even in the case where light should be transmitted through the remaining ink detecting portion with the decrease of water-based ink, there is the possibility that the water-based ink remains in the remaining ink detecting portion and inhibits the light transmission. This may cause a detection error. In order to solve the problem, it has been proposed to form a water-repellent membrane (ink-repellent membrane) on the remaining ink detecting portion of the ink cartridge by applying polyorganosiloxane.
However, in the aforementioned method, there is the possibility that the water-repellent membrane comes off over time, for example, and the prevention of the error in the detection of remaining ink is insufficient. Further, in the method, there is also the problem that the water-based ink may be contaminated with the water-repellent membrane that came off.
An ink cartridge for containing a water-based ink for ink-jet recording comprising a pigment, water, and a nonionic surfactant comprises a remaining ink detecting portion detecting an amount of remaining ink on the basis of whether or not light is transmitted therethrough. The remaining ink detecting portion is formed of a hydrophobic resin containing a water-repellent material in the proportion of 0.14 wt % to 10 wt %.
An ink-jet recording apparatus comprises an ink cartridge, an ink ejecting unit, and a remaining ink detecting unit. The ink ejecting unit ejects an ink contained in the ink cartridge. The ink cartridge is the aforementioned ink cartridge. The remaining ink detecting unit comprises a transmissive optical sensor provided with a light emitting portion and a light receiving portion. The remaining ink detecting portion of the ink cartridge is placed between the light emitting portion and the light receiving portion.
The “hydrophobic resin containing a water-repellent material” is a hydrophobic resin in which a water-repellent material is mixed by a polymer blend or a polymer alloy, for example.
The range “0.14 wt % to 10 wt %” is the proportion of the water-repellent material relative to the total amount of the water-repellent material and the hydrophobic resin.
The ink cartridge described below is illustrative only and the present invention is not limited to the embodiment below.
As shown in the external perspective view of
As shown in the external perspective view of
As shown in
Next, referring to
The remaining ink detecting portion 140 is formed of a hydrophobic resin containing a water-repellent material in the proportion of 0.14 wt % to 10 wt %. The material for forming the remaining ink detecting portion 140 may also comprise components other than the water-repellent material and hydrophobic resin. When the proportion of the water-repellent material is 0.14 wt % or more, the loss of water repellency due to coming off of a water-repellent membrane as a conventional water-repellent membrane is prevented and the sufficient water repellency is kept over a long period of time. Therefore, even when the water-based ink of higher penetration using a nonionic surfactant is contained, the error in the detection of remaining ink is sufficiently prevented. Further, when the proportion of the water-repellent material is 10 wt % or less, the elution of the water-repellent material from the remaining ink detecting portion to the water-based ink is prevented and the ejection failure due to the elution does not occur. The proportion of the water-repellent material may be in the range from 0.35 wt % to 6.4 wt %.
As the hydrophobic resin, for example, a resin having surface free energy of 45 J/m2 or less may be used. Examples thereof include polyolefin (for example, polypropylene (PP), surface free energy: 29 J/m2; and polyethylene (PE), surface free energy: 31 J/m2), polyethylene terephthalate (PET, surface free energy: 43 J/m2), polystyrene (PS, surface free energy: 33 J/m2), polymethylmethacrylate (PMM, surface free energy: 39 J/m2), polyvinyl chloride (surface free energy: 39 J/m2), and the like. Among them, in view of a solvent resistance (ink resistance), a light transmissivity (transparency), and a workability, polyolefin is preferred, polypropylene (PP) and polyethylene (PE) are more preferred, and polypropylene (PP) is particularly preferred. For example, commercially available hydrophobic resins may be used. Examples thereof include “PRIME POLYPRO® J227T” (PP) and “PRIME POLYPRO® J-3000GP” (PP) manufactured by Prime Polymer Co., Ltd; and the like. One of the hydrophobic resins may be used alone or two or more of them may be used in combination.
As the water-repellent material, a material having lower surface free energy than the hydrophobic resin that is used together may be used. Examples thereof include silicon-containing compounds, fluorine-containing compounds, and the like. For example, in the case where polyolefin is used as the hydrophobic resin, polyorganosiloxane may be used as the water-repellent material because polyorganosiloxane has superior mixability with polyolefin. For example, commercially available water-repellent materials may be used. Examples thereof include “POLYFINE® MF18R” (containing 7 wt % of polyorganosiloxane) manufactured by Prime Polymer Co., Ltd., “DOW CORNING TORAY BY27-001” (containing 50 wt % of polyorganosiloxane) manufactured by Dow Corning Toray Co., Ltd, and the like. One of the water-repellent materials may be used alone or two or more of them may be used in combination. In Examples that will be described below, the commercially available water-repellent materials containing polyorganosiloxane are mixed with the hydrophobic resin. However, a water-repellent material containing no other components may be mixed with the hydrophobic resin.
Next, referring to
The state of the ink reservoir 100 shown in
As shown in
The frame portion 180 has faces that are parallel to the width direction of the ink tank 110. The frame portion 180 is provided with an outer peripheral welded portion 400, inner welded portions 411 to 417, and connecting portions 420, 430, and 440. The outer peripheral welded portion 400 is a vertical wall that demarcates the inner space of the main body portion 170. The inner welded portions 411 to 417 have faces that are parallel to the width direction of the ink tank 110 and are placed at the inside of the outer peripheral welded portion 400. The connecting portions 420, 430, and 440 have faces that are orthogonal to the width direction of the ink tank 110 and connect the outer peripheral welded portion 400 and the inner welded portions 411 to 417. The connecting portion 420 connects the outer peripheral welded portion 400 and the inner welded portion 411 at the lower left of
As shown in
As shown in
The air intake portion 130 comprises a cylindrical air communication passage 131 and an air intake mechanism 132 having a rodlike valve opening portion 132a. The air communication passage 131 is in communication with the ink tank 110 and is extended in the longitudinal direction. A part of the valve opening portion 132a is inserted into the air communication passage 131 and the valve opening portion 132a is protruded toward the outside of the air communication passage 131. The air intake mechanism 132 closes a passage of air in the condition where the ink cartridge 1 is not installed in the ink-jet recording apparatus 1000 and opens the passage of air in the condition where the ink cartridge 1 is installed in the ink-jet recording apparatus 1000 and the valve opening portion 132a is brought into contact with an installation surface 1013 (see
In the ink tank 110, provided is a sensor arm 470 that is capable of pivoting about a pivot provided in the vicinity of the lower left of
The sensor arm 470 is a pivoting member, which is pivotally supported in the ink tank 110 and pivots in response to the amount of remaining ink. The sensor arm 470 comprises an attachment portion 472, a float portion 471, and an arm portion 473. The attachment portion 472 is provided with an attachment shaft 472a that is attached to the substantially C-shaped arm holding portion 425 (see
The sensor arm 470 comprises the detection target portion 473a at one end (the left end in
In the arm portion 473, a rib 473b that is protruded in the width direction (the left-right direction in
As described above, the sensor arm 470 is composed of a resin material with a specific gravity lower than the specific gravity of the ink. Further, the volume of the float portion 471 is made sufficiently larger than that of the arm portion 473. In the sensor arm 470, it is set that when the float portion 471 is positioned inside the ink liquid, the moment in the counterclockwise direction in
Next, referring to
As shown in
As described above, the remaining ink detecting portion 140 has a light transmissivity, and placed between the light emitting portion 1014a and the light receiving portion 1014b (see
As shown in
Next, referring to
The first case member 210 and the second case member 220 are formed into substantially the same shape. The first case member 210 has case cutout portions 211, 212, and 213. The second case member 220 has cutout portions 221, 222, and 223. In the condition where the first case member 210 and the second case member 220 sandwich the ink reservoir 100, the case cutout portions 211 and 221 form a substantially circular through hole from which a part of the ink supply portion 120 is exposed to the outside, the case cutout portions 212 and 222 form a substantially circular through hole from which a part of the air intake portion 130 is exposed to the outside, and the case cutout portions 213 and 223 form through holes, at the both sides (the sides in the up-and-down direction in
Next, the outer shape of the case 200 will be described. At the both ends in the short-side direction of the first case member 210 and the second case member 220, formed are stepped portions recessed relative to the surfaces of the first case member 210 and the second case member 220 and extended in the longitudinal direction. At the stepped portions, the first case member 210 and the second case member 220 are welded and the ink reservoir 100 is secured to the case 200. The stepped portions on the ink supply portion 120 side (the right front side in
The ink cartridge 1 may be produced, for example, as follows.
First, the water-repellent material and the hydrophobic resin are mixed, for example, by a polymer blend or a polymer alloy to obtain a hydrophobic resin containing the water-repellent material in the aforementioned proportion. Then, the remaining ink detecting portion 140 is formed by subjecting the hydrophobic resin containing the water-repellent material to injection molding.
Next, the part of the ink reservoir 100 excluding the remaining ink detecting portion 140 and the film 160 (hereinafter, referred to as the “ink reservoir part”) is formed by subjecting the resin material to injection molding. Then, a bonded product is obtained by bonding the remaining ink detecting portion 140 with the ink reservoir part.
Next, the sensor arm 470 is formed by subjecting the resin material to injection molding. Subsequently, the sensor arm 470 is installed in the bonded product, and the film 160 is welded by ultrasonic welding. Thereby the ink reservoir 100 in which the sensor arm 470 is installed is formed.
The first case member 210 and the second case member 220 are each formed by subjecting the resin material to injection molding. Subsequently, the ink reservoir 100 in which the sensor arm 470 is installed is sandwiched between the first case member 210 and the second case member 220, and then the first case member 210 and the second case member 220 are welded. Thereby the ink cartridge 1 is obtained.
In the present embodiment, the remaining ink detecting portion 140 and the ink reservoir part are formed separately and then bonded. In the production of the ink cartridge, the remaining ink detecting portion 140 and the ink reservoir part may be integrally molded by injection molding. In this case, the ink reservoir part is formed using the hydrophobic resin containing the same water-repellent material in the aforementioned proportion as that of the remaining ink detecting portion 140. In the integral molding, one of the remaining ink detecting portion 140 and the ink reservoir part may be formed beforehand and then the other may subsequently be formed in the same molding die by performing injection twice, namely, by separately injecting the hydrophobic resin containing the water-repellent material in the aforementioned proportion to the molding die at the part where the remaining ink detecting portion 140 is formed and injecting the resin material to the molding die at the part where the ink reservoir part is formed.
The ink cartridge contains a water-based ink for ink-jet recording comprising a pigment, water, and a nonionic surfactant (hereinafter this may also be referred to simply as the “water-based ink” or “ink”). Even when the ink cartridge contains a water-based ink comprising a pigment that does not have a light transmissivity, the ink cartridge sufficiently prevents the error in the detection of remaining ink that is caused by the water-based ink that remains in the remaining ink detecting portion 140.
Examples of the pigment include carbon blacks, inorganic pigments, organic pigments, and the like. Examples of the carbon blacks include furnace black, lamp black, acetylene black, channel black, and the like. Examples of the inorganic pigments include titanium oxide pigments, iron oxide pigments, carbon black pigments, and the like. Examples of the organic pigments include azo pigments such as azo lake pigments, insoluble azo pigments, condensed azo pigments, chelate azo pigments, and the like; polycyclic pigments such as phthalocyanine pigments, perylene and perynone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, and the like; dye lake pigments such as basic dye lake pigments, acid dye lake pigments, and the like; nitro pigments; nitroso pigments; aniline black daylight fluorescent pigments; and the like. Further, other pigments may be used as long as they are dispersible to an aqueous phase. Examples of the pigments include C. I. Pigment Black 1, 6, and 7; C. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 78, 150, 151, 154, 180, 185, and 194; C. I. Pigment Orange 31 and 43; C. I. Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1, 112, 122, 123, 139, 144, 146, 149, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 221, 222, 224, and 238; C. I. Pigment Violet 196; C. I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22, and 60; C. I. Pigment Green 7 and 36; and the like.
The pigment may be a self-dispersible pigment. The self-dispersible pigment is a pigment in which at least one of hydrophilic functional groups such as a carbonyl group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group and their salts is introduced into a pigment particle directly or through other groups by a chemical bond, and therefore is dispersible to water without using a dispersant. As for the self-dispersible pigment, for example, self-dispersible pigments treated according to the methods described in JP8 (1996)-3498A, JP2000-513396A, JP2009-515007A, and the like may be used. For example, commercially available self-dispersible pigments may be used. Examples thereof include “CAB-O-JET® 200”, “CAB-O-JET® 250C”, “CAB-O-JET® 260M”, “CAB-O-JET® 270Y”, “CAB-O-JET® 300”, “CAB-O-JET® 400”, “CAB-O-JET® 450C”, “CAB-O-JET® 465M”, and “CAB-O-JET® 470Y” manufactured by Cabot Specialty Chemicals, Inc.; “BONJET® BLACK CW-2” and “BONJET® BLACK CW-3” manufactured by Orient Chemical Industries, Ltd.; “LIOJET® WD BLACK 002C” manufactured by TOYO INK MFG. CO., LTD.; and the like.
As a pigment used as a material of the self-dispersible pigment, either an inorganic pigment or an organic pigment may be used. Further, examples of the pigment suitable to perform the aforementioned treatment include carbon blacks such as “MA8” and “MA100” manufactured by Mitsubishi Chemical Corporation; “COLOR BLACK FW 200” manufactured by Evonik Degussa; and the like.
The amount of the pigment (solid content) to be added relative to the total amount of the water-based ink is not particularly limited and decided suitably according to, for example, a desired optical density, a desired color, or the like. The solid content of pigment is, for example, in the range from 0.1 wt % to 20 wt % and in the range from 0.5 wt % to 10 wt %.
The water-based ink may further comprise, for example, a dye(s) as a coloring agent in addition to the pigment.
The water may be ion-exchange water or pure water. The amount of the water to be added relative to the total amount of the water-based ink (the proportion of the water in the water-based ink) is, for example, in the range from 10 wt % to 90 wt % and in the range from 40 wt % to 80 wt %. The proportion of the water in the water-based ink may be, for example, the balance of the water-based ink, excluding other components.
The nonionic surfactant has a capacity for increasing the penetration of the water-based ink relative to a recording medium, for example. Examples of the nonionic surfactant include polyoxyalkylene alkyl ether surfactants, acetylene glycol surfactants, silicone surfactants, and the like. Examples of the polyoxyalkylene alkyl ether surfactants include polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, and the like. Examples of the acetylene glycol surfactants include ethylene oxide adducts of acetylenediol, and the like. Examples of the silicone surfactants include polyether silicone surfactants, and the like. For example, commercially available nonionic surfactants may be used. Examples thereof include “EMULGEN® 109P” (polyoxyethylene alkyl ether) and “EMULGEN® MS-110” (polyoxypropylene alkyl ether) manufactured by Kao Corporation; “OLFIN® E1010” (ethylene oxide (10 mol) adduct of acetylenediol) manufactured by Nissin Chemical Industry Co., Ltd.; “KF6011” (polyether-modified silicone) manufactured by Shin-Etsu Chemical Co., Ltd.; and the like. One of the nonionic surfactants may be used alone or two or more of them may be used in combination.
The amount of the nonionic surfactant to be added relative to the total amount of the water-based ink (the proportion of the nonionic surfactant in the water-based ink) may be in the range from 0.17 wt % to 1.0 wt % and in the range from 0.2 wt % to 0.8 wt %.
The water-based ink may further comprise an anionic surfactant and a cationic surfactant in addition to the nonionic surfactant.
The water-based ink may further comprise a water-soluble organic solvent. Examples of the water-soluble organic solvent include a humectant and a penetrant. The humectant prevents a water-based ink from drying at a nozzle tip portion of an ink-jet head, for example. The penetrant adjusts a drying rate of a water-based ink on a recording medium, for example.
Examples of the humectant include, but not limited to, lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and the like; amides such as dimethylformamide, dimethylacetamide, and the like; ketones such as acetone and the like; ketoalcohols such as diacetone alcohol and the like; ethers such as tetrahydrofuran, dioxane, and the like; polyalcohols such as polyalkylene glycols, alkylene glycols, glycerin, and the like; 2-pyrrolidone; N-methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone; and the like. Examples of the polyalkylene glycols include polyethylene glycol, polypropylene glycol, and the like. Examples of the alkylene glycols include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, hexylene glycol, and the like. One of the humectants may be used alone or two or more of them may be used in combination. Among them, for example, the humectant may be polyalcohols such as alkylene glycols, glycerin, and the like.
The amount of the humectant to be added relative to the total amount of the water-based ink is, for example, in the range from 0 wt % to 95 wt %, in the range from 5 wt % to 80 wt %, and in the range from 5 wt % to 50 wt %.
Examples of the penetrant include glycol ethers. Examples of the glycol ethers include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, propylene glycol-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether, tripropylene glycol-n-butyl ether, and the like. One of the penetrants may be used alone or two or more of them may be used in combination.
The amount of the penetrant to be added relative to the total amount of the water-based ink is, for example, in the range from 0 wt % to 20 wt %, in the range from 0.1 wt % to 15 wt %, and in the range from 0.5 wt % to 10 wt %.
The water-based ink may further comprise a conventionally known additive(s), if necessary. Examples of the additive include a pH adjuster, a viscosity modifier, a surface tension modifier, a mildewproofing agent, and the like. Examples of the viscosity modifier include polyvinyl alcohols, celluloses, water-soluble resins, and the like.
The water-based ink may be prepared, for example, by uniformly mixing the pigment, water, the nonionic surfactant, and optionally other added components by a conventionally known method, and then removing sediments with a filter or the like.
The ink cartridge may be used, for example, for the ink-jet recording apparatus.
The light emitted from the light emitting portion 1014a may be infrared light in view of the transmissivity relative to the ink stored in the ink cartridge and the prevention of deterioration of the ink, although visible light is applicable.
Next, referring to
As shown in
The transmissive optical sensor 1014 is arranged on the installation surface 1013 of the installation portion 1010. The transmissive optical sensor 1014 is formed into a substantially inverted C shape, with the open end of the inverted C shape being the light emitting portion 1014a, which emits light, and the other end being the light receiving portion 1014b, which receives light. The light emitting portion 1014a and the light receiving portion 1014b are attached projecting from the installation surface 1013 so as to be inserted into the through holes formed by the case cutout portions 213 and 223 and the remaining ink detecting portion 140 respectively. The transmissive optical sensor 1014 is configured not to send (or to send) a signal to a control board (not shown) provided on the ink-jet recording apparatus 1000 when the light emitted from the light emitting portion 1014a is received by the light receiving portion 1014b, and to send (or not to send) a signal to the control board when the light emitted from the light emitting portion 1014a is blocked and is not received by the light receiving portion 1014b.
Further, on the side of the installation surface 1013 corresponding to the ink supply portion 120 (the lower side in
Moreover, the installation portion 1010 is provided with an engagement member 1017, which engages and rotates with the engagement potions 216a and 226a of the case 200, on the tip (the right side in
Installation of the ink cartridge 1 is carried out by inserting such that the first case welded portions 216 and 226 of the case 200 contact with the support portion 1012 and pushing so that the first case welded portions 216 and 226 slide over the support portion 1012. In other words, as shown in
As shown in
As shown in
Further, when the ink cartridge 1 is installed in the installation portion 1010, the ink extraction tube 1015 is inserted into the ink supply portion 120, enabling ink supply, and the transmissive optical sensor 1014 is inserted into the through holes formed by the case cutout portions 213 and 223 and the remaining ink detecting portion 140, enabling the detection of remaining ink.
With the ink cartridge 1 of the present embodiment, when the ink cartridge 1 is installed in the ink-jet recording apparatus 1000, the remaining ink detecting portion 140 is placed between the light emitting portion 1014a and the light receiving portion 1014b of the transmissive optical sensor 1014 provided in the ink-jet recording apparatus 1000. Therefore, the detection target portion 473a is reliably detected with a simple mechanism.
Next, referring to
As shown in
Subsequently, when the ink in the ink tank 110 is decreased and the arm portion 473 is exposed from the ink, the buoyancy acting on the arm portion 473 decreases. As a result, the counterclockwise moment acting on the sensor arm 470 becomes smaller, but there is no change of the fact that the counterclockwise moment is greater than the clockwise moment, so the sensor arm 470 stays at the position shown in
In the ink cartridge 1 of the present embodiment, the amount of remaining ink is detected with the sensor arm 470. However, the ink cartridge may be the one in which ink itself obstructs detection light and that detects the amount of remaining ink by the light transmitted as ink decreases.
Next, Examples are described together with Comparative Examples. However, the present invention is not limited to the following Examples.
The water-repellent materials and the hydrophobic resins (table 1) were mixed by a polymer blend, the resultant polymer-blended products were subjected to injection molding and the parts of the ink reservoir 100 shown in
An ink solvent was obtained by uniformly mixing the water-based ink composition components (Table 2) excluding self-dispersible pigment dispersion. Next, the ink solvent was added to each of the self-dispersible pigment dispersion, and mixed uniformly. Thereafter, the resultant mixtures were filtered through a cellulose acetate type membrane filter (pore diameter: 3.00 nm) manufactured by Toyo Roshi Kaisha, Ltd. Thereby water-based inks 1 to 7 for ink-jet recording were obtained.
Using the test pieces 1 to 11 in combination with each of the water-based inks 1 to 7, (a) water repellency, (b) quality of recorded image, and (c) elution of water-repellent material were measured and evaluated according to the following methods.
The test pieces were immersed in the water-based inks for 1 minute and taken out. The time (water-repelling time) between the time when the test piece was taken out from the water-based ink and the time when the adhered water-based ink on the test piece was run down (was gone) was measured, and the evaluation was made according to the following evaluation criteria.
AA: water-repelling time was shorter than 30 seconds
A: water-repelling time was 30 seconds or longer and shorter than 120 seconds
C: water-repelling time was unmeasurable (adhered water-based ink on test piece has never gone)
Using a digital multi-function center DCP-385C which on an ink-jet printer mounted, manufactured by Brother Industries, Ltd., evaluation samples were prepared by recording monochrome patches at 600 dpi×600 dpi resolution and 100% coverage on recording paper (“My Paper” manufactured by Ricoh Co., Ltd.) with the water-based inks of Examples and Comparative Examples.
AA: White streaks were not observed and quality of recorded image was excellent
A: White streaks were hardly observed and quality of recorded image was good
C: White streaks were clearly observed and quality of recorded image was poor
10 mL of each of the water-based inks was put in an airtight container. Then, the test pieces were immersed in the water-based inks in the containers and were allowed to stand in a thermostat bath at 60° C. for two weeks. After being allowed to stand, the test pieces were taken out from the water-based inks. The water-based inks that remain in the containers were each filtered through a cellulose acetate type membrane filter (pore diameter: 0.8 μm) manufactured by ADVANTEC, and the time (X) required for filtration was measured. Further, as a control, each of the water-based inks alone was allowed to stand under the same conditions (60° C. for two weeks). After being allowed to stand, the water-based inks that remain in the containers were each filtered through the filter, and the time required for filtration was measured. The time required for filtering the control was defined as the criterion time (Y). The ratio of the time required for filtering the water-based ink, in which the test piece was immersed, relative to the criterion time [Z=X/Y (ratio)] was obtained. The evaluation was made based on the ratio Z according to the following evaluation criteria.
AA: Ratio Z is less than 1.1
A: Ratio Z is 1.1 or more and less than 1.2
C: Ratio Z is 1.2 or more
The evaluation results of Examples 1 to 8 and Comparative Examples 1 to 5 are summarized in Table 3.
As summarized in Table 3, Examples 1 to 8 in which the test pieces 1 to 8, in which the proportion of the water-repellent material was in the range from 0.14 wt % to 10 wt %, were used showed favorable results in the water repellency evaluation, the recorded image quality evaluation, and the water-repellent material elution evaluation. Especially, Examples 1 to 4 and 7 in which the test pieces 1 to 4 and 7, in which the proportion of the water-repellent material is in the range from 0.35 wt % to 6.4 wt %, were used showed very favorable results in the water repellency evaluation and the water-repellent material elution evaluation. With respect to Examples 1 to 8, particularly favorable results were obtained in the cases in which the water-based inks 1, 2, and 4, in which the proportion of the nonionic surfactant is in the range from 0.17 wt % to 1.0 wt %, were used. In contrast, Comparative Example 1 in which the test piece 9, in which the proportion of the water-repellent material is 0.07 wt %, was used showed an unfavorable result in the water repellency evaluation. Comparative Example 2 in which the test piece 10, in which the proportion of the water-repellent material is 12.0 wt %, was used showed an unfavorable result in the water-repellent material elution evaluation. Comparative Example 3 in which the test piece 11 that does not contain the water-repellent material was used showed an unfavorable in the water repellency evaluation in the cases where the water-based inks 1 and 3 were used, and showed an unfavorable result in the recorded image quality evaluation in the case where the water-based ink 5 that contains only the anionic surfactant as a surfactant was used. Comparative Example 4 in which the test piece 3 and the water-based ink 6 that contains only anionic surfactant as a surfactant were used showed an unfavorable result in the recorded image quality evaluation. Comparative Example 5 in which the test piece 3 and the water-based ink 7 that does not contain a surfactant were used showed an unfavorable result in the recorded image quality evaluation.
It will be obvious to those having skill in the art that many changes may be made in the above-described details of the particular aspects described herein without departing from the spirit or scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-105874 | Apr 2010 | JP | national |
