JP2010077277A - Aqueous ink for use in inkjet recording, inkjet recording apparatus, corrosion inhibitor, and method for preventing inkjet head from corrosion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide such aqueous ink for use in inkjet recording, even when applied to an inkjet head using an easily corrodible lead titanate zirconate, as is capable of preventing the inkjet head from the corrosion. <P>SOLUTION: This aqueous ink for use in inkjet recording is used in an inkjet recording apparatus, wherein the ink contains a strongly corrosive dye, water and magnesium ion, and a blending quantity of the magnesium ion is of 50 mol% or more relative to the whole molar quantity of the strongly corrosive dye. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an aqueous inkjet recording ink, an inkjet recording apparatus, a corrosion inhibitor, and an inkjet head corrosion prevention method.

In an inkjet head that ejects ink in an inkjet recording apparatus, a pressure chamber is formed in a state corresponding to an ink ejection nozzle, and the pressure chamber is filled with ink. A piezoelectric element is used to form the pressure chamber. The piezoelectric element is an element whose shape is changed by application of a voltage. In the ink jet head, a voltage is applied to the piezoelectric element to change its shape, thereby applying pressure to the ink in the pressure chamber and ejecting the ink from the nozzle. As a material for forming the piezoelectric element, lead zirconate titanate (PZT: PbTiO ₃ .PbZrO ₃ ) may be used (Patent Document 1).
JP 2008-149733 A

  In the pressure chamber of the inkjet head, the piezoelectric element may be in direct contact with the ink. In this case, there is a problem that lead zirconate titanate (hereinafter sometimes referred to as “PZT”), which is a material for forming the piezoelectric element, is corroded by ink. The corrosive strength against PZT varies depending on the type of ink. Some of the PZTs are particularly susceptible to corrosion by ink. The corrosion of the PZT is significant at the interface between the sintered and bonded particles. In the piezoelectric element, when the PZT corrodes, the ink penetrates into the piezoelectric element, and the function of the piezoelectric element is impaired. If the corrosion is significant, ink may not be ejected.

  Accordingly, an object of the present invention is to provide a water-based ink for ink jet recording capable of preventing corrosion of the ink jet head even when applied to an ink jet head using PZT which is easily corroded.

The aqueous inkjet recording ink of the present invention is an aqueous inkjet recording ink used in an inkjet recording apparatus,
The ink includes a dye that satisfies the following condition (I), water, and magnesium ions (hereinafter, sometimes referred to as “Mg ions”),
The Mg ion content is 50 mol% or more based on the total molar amount of the dye satisfying the condition (I).

Condition (I): When a PZT-containing sample satisfying the following condition (II) is immersed in an aqueous dye solution under the following conditions (a) to (d), the amount of lead elution from the sample (hereinafter referred to as “Pb elution amount”) Is 3 ppm to 10 ppm.
(A) Concentration of the aqueous dye solution: 5.6 × 10 ⁻³ mol / L
(B) Amount of dye aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(C) Temperature of the dye aqueous solution: 70 ° C
(D) Immersion time: 5 days

Condition (II): When a PZT-containing sample was immersed in an aqueous solution of ethylenediaminetetraacetic acid / disodium salt (hereinafter sometimes referred to as “EDTA · 2Na”) under the following conditions (e) to (h), Pb from the sample The elution amount is 180 ppm to 300 ppm.
(E) EDTA · 2Na aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) EDTA · 2Na aqueous solution amount (Y): Y = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(G) Temperature of the EDTA · 2Na aqueous solution: 70 ° C
(H) Immersion time: 5 days

  In order to achieve the above object, the present inventor conducted a series of studies, and in the process, found that the causative substance of corrosion was a dye in the dye ink. Based on this knowledge, further research has been conducted. As a result, if Mg ions are mixed in the ink at a ratio of 50 mol% or more with respect to the total number of moles of the dye, an ink using a strong corrosive dye and PZT that easily corrodes. It was found that even when combined with a head, corrosion of the PZT can be prevented, and the present invention has been achieved. According to the present invention, the degree of freedom of the combination of the dye ink and the inkjet head is expanded, in other words, the range of selection between the dye ink and the inkjet head is expanded.

The aqueous ink for inkjet recording of the present invention preferably further satisfies the following condition (III).

Condition (III): When a sample satisfying the condition (II) is immersed in the ink under the following conditions (i) to (k), the Pb elution amount from the sample is 4 ppm or less.
(I) The ink amount (Z): Z = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(J) Ink temperature: 70 ° C.
(K) Immersion time: 5 days

  The measurement of the Pb elution amount under the conditions (I), (II) and (III) is performed using, for example, an ICP emission spectroscopic analyzer (for example, ICPE-9000 manufactured by Shimadzu Corporation). be able to.

  In the water-based ink for inkjet recording of the present invention, the dye satisfying the condition (I) is C.I. I. Direct Yellow 86 and C.I. I. The aspect containing at least one of the direct yellow 132 may be sufficient. Both the dyes are dyes having a strong corrosive power against PZT.

The ink jet recording apparatus of the present invention is an ink jet recording apparatus that includes an ink storage portion and an ink discharge means, and discharges the ink stored in the ink storage portion by the ink discharge means,
The water-based ink for inkjet recording of the present invention is stored in the ink storage portion.

The corrosion inhibitor of the present invention is a corrosion inhibitor for preventing corrosion by dye ink of an inkjet head,
The dye ink contains a dye that satisfies the following condition (I):
The corrosion inhibitor includes Mg ions,
The content of the Mg ions is an amount that is 50 mol% or more based on the total molar amount of the dye that satisfies the following condition (I).

Condition (I): When a PZT-containing sample satisfying the following condition (II) is immersed in the dye aqueous solution under the following conditions (a) to (d), the Pb elution amount from the sample is 3 ppm to 10 ppm.
(A) Concentration of the aqueous dye solution: 5.6 × 10 ⁻³ mol / L
(B) Amount of dye aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(C) Temperature of the dye aqueous solution: 70 ° C
(D) Immersion time: 5 days

Condition (II): When a PZT-containing sample is immersed in an EDTA · 2Na aqueous solution under the following conditions (e) to (h), the Pb elution amount from the sample is 180 ppm to 300 ppm.
(E) EDTA · 2Na aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) EDTA · 2Na aqueous solution amount (Y): Y = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(G) Temperature of the EDTA · 2Na aqueous solution: 70 ° C
(H) Immersion time: 5 days

The corrosion prevention method of the present invention is an inkjet head corrosion prevention method for preventing corrosion of an inkjet head by dye ink,
The dye ink contains a dye satisfying the following condition (I) and the corrosion inhibitor of the present invention.

Condition (I): When a PZT-containing sample satisfying the following condition (II) is immersed in the dye aqueous solution under the following conditions (a) to (d), the Pb elution amount from the sample is 3 ppm to 10 ppm.
(A) Concentration of the aqueous dye solution: 5.6 × 10 ⁻³ mol / L
(B) Amount of dye aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(C) Temperature of the dye aqueous solution: 70 ° C
(D) Immersion time: 5 days

Condition (II): When a PZT-containing sample is immersed in an EDTA · 2Na aqueous solution under the following conditions (e) to (h), the Pb elution amount from the sample is 180 ppm to 300 ppm.
(E) EDTA · 2Na aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) EDTA · 2Na aqueous solution amount (Y): Y = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(G) Temperature of the EDTA · 2Na aqueous solution: 70 ° C
(H) Immersion time: 5 days

  Next, the water-based ink for inkjet recording of the present invention will be described in detail. The water-based ink for inkjet recording of the present invention (hereinafter sometimes simply referred to as “ink”) contains a dye, water, and Mg ions. Even when the ink is used in an inkjet head using PZT that easily corrodes that satisfies the condition (II), corrosion of the inkjet head can be prevented. In the ink, the dye contains a highly corrosive dye that satisfies the condition (I).

  Examples of the dye satisfying the condition (I) include C.I. I. Direct Yellow 86 (DY86), C.I. I. Direct yellow 132 (DY132) and the like can be mentioned.

  C. above. I. Direct yellow 86 (DY86) is a dye represented by the following structural formula (1), for example.

  C. above. I. Direct yellow 132 (DY132) is, for example, a dye represented by the following structural formula (2).

  The blending amount of the dye that satisfies the condition (I) with respect to the entire ink is not limited, and is, for example, 0.1 wt% to 10 wt%, preferably 0.2 wt% to 8 wt%. More preferably, it is 0.3 wt% to 5 wt%. As the dye satisfying the condition (I), one type may be used alone, or two or more types may be used in combination.

  The dye may be composed of only a dye that satisfies the condition (I), or may include a dye other than the dye that satisfies the condition (I). Examples of the dye other than the dye satisfying the condition (I) include C.I. I. Direct black, C.I. I. Direct Blue, C.I. I. Direct Red, C.I. I. C. other than direct yellow 86 and 132 I. Direct yellow, C.I. I. Direct orange, C.I. I. Direct violet, C.I. I. Direct Brown, C.I. I. Direct Green, C.I. I. Acid Black, C.I. I. Acid Blue, C.I. I. Acid Red, C.I. I. Acid Yellow, C.I. I. Acid Orange, C.I. I. Acid Violet, C.I. I. Basic Black, C.I. I. Basic blue, C.I. I. Basic Red, C.I. I. Basic violet and C.I. I. For example, food black. C. above. I. Examples of direct black include C.I. I. Direct black 17, 19, 32, 51, 71, 108, 146, 154, 168 and the like can be mentioned. C. above. I. Examples of direct blue include C.I. I. Direct blue 6, 22, 25, 71, 86, 90, 106, and 199. C. above. I. Examples of direct red include C.I. I. Direct red 1, 4, 17, 28, 83, and 227. C. above. I. Examples of direct yellow include C.I. I. Direct yellow 12, 24, 26, 98, 142 and the like. C. above. I. Examples of direct orange include C.I. I. Direct orange 34, 39, 44, 46 and 60 are listed. C. above. I. Examples of direct violet include C.I. And I direct violet 47 and 48. C. above. I. Examples of direct brown include C.I. I. Direct brown 109 etc. are mention | raise | lifted. C. above. I. Examples of direct green include C.I. I. Direct green 59 etc. are mention | raise | lifted. C. above. I. Examples of acid black include C.I. I. Acid Black 2, 7, 24, 26, 31, 52, 63, 112, 118 and the like. C. above. I. Examples of acid blue include C.I. I. Acid Blue 9, 22, 40, 59, 93, 102, 104, 117, 120, 167, 229, and 234. C. above. I. As acid red, for example, C.I. I. Acid Red 1, 6, 32, 37, 51, 52, 80, 85, 87, 92, 94, 115, 180, 256, 289, 315 and 317. C. above. I. Examples of acid yellow include C.I. I. Acid Yellow 11, 17, 23, 25, 29, 42, 61, 71 and the like. C. above. I. Examples of acid orange include C.I. I. Acid orange 7 and 19 etc. are mentioned. C. above. I. Examples of acid violet include C.I. I. Acid Violet 49 and the like. C. above. I. Examples of basic black include C.I. I. Basic black 2 etc. are raised. C. above. I. Examples of basic blue include C.I. I. Basic Blue 1, 3, 5, 7, 9, 24, 25, 26, 28, 29, and the like are listed. C. above. I. Examples of basic red include C.I. I. Basic Red 1, 2, 9, 12, 13, 14, and 37 are listed. C. above. I. Examples of basic violet include C.I. I. And basic violet 7, 14, and 27. C. above. I. Examples of food black include C.I. I. Food black 1 and 2 etc. are mentioned. These dyes are excellent in properties such as sharpness, water solubility and stability. Only one type of dye other than the dye satisfying the condition (I) may be used, or two or more types may be used.

  The ink may contain a colorant other than a dye. Examples of colorants other than the dye include pigments.

  The water is preferably ion exchange water or pure water. The blending amount (water ratio) of the water with respect to the entire ink is appropriately determined according to desired ink characteristics and the like. The said water ratio is good also as the remainder of another component, for example.

As described above, the compounding amount of the Mg ions with respect to the entire ink is 50 mol% or more, preferably 50 mol% to 200 mol%, more preferably, based on the total molar amount of the dye satisfying the condition (I). Is 60 mol% to 110 mol%. Examples of the counter ion of Mg ion include chloride ion (Cl ⁻ ), bromide ion (Br ⁻ ), and sulfate ion (SO ₄ ²⁻ ). The Mg ions may be added to the ink in the form of a salt such as MgCl ₂ , MgBr _2, or MgSO ₄ .

  The ink may further include a wetting agent that prevents drying of the ink in the nozzle portion of the inkjet head and a penetrating agent that adjusts the drying speed on the recording medium.

  The wetting agent is not limited, and examples thereof include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; dimethylformamide, dimethylacetamide, and the like. Amides; ketones such as acetone; keto alcohols such as diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyhydric alcohols such as polyalkylene glycol, alkylene glycol, and glycerin; 2-pyrrolidone; N-methyl-2-pyrrolidone; , 3-dimethyl-2-imidazolidinone and the like. The polyalkylene glycol is not limited, and examples thereof include polyethylene glycol and polypropylene glycol. The alkylene glycol is not limited, and examples thereof include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, and hexylene glycol. Among these, polyhydric alcohols such as alkylene glycol and glycerin are preferable. The wetting agent may be used alone or in combination of two or more.

  The blending amount (humectant ratio) of the humectant with respect to the entire ink is, for example, 0% by weight to 95% by weight, preferably 10% by weight to 80% by weight, and more preferably 10% by weight to 50% by weight.

  The penetrant is not limited, and examples thereof include glycol ethers. The glycol ether is not limited, for example, 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 And ether, tripropylene glycol-n-butyl ether and the like. One kind of the penetrant may be used alone, or two or more kinds may be mixed and used.

  The blending amount of the penetrant (the penetrant ratio) with respect to the entire ink is not particularly limited, and is, for example, 0 wt% to 20 wt%. By setting the penetrant ratio within the above range, the penetrability of the ink into a recording medium such as a recording paper can be further improved. The penetrant ratio is preferably 0.1% by weight to 15% by weight, and more preferably 0.5% by weight to 10% by weight.

  The ink may further contain a conventionally known additive as required. Examples of the additive include a surfactant, a viscosity modifier, a surface tension modifier, and an antifungal agent. Examples of the viscosity modifier include polyvinyl alcohol, cellulose, and a water-soluble resin.

  The ink can be prepared, for example, by uniformly mixing the dye, water, and Mg ions with other additive components as required, by a conventionally known method, and removing insoluble matters with a filter or the like.

  Examples of the PZT-containing sample that satisfies the condition (II) include a piezoelectric ceramic material “Piezotite (registered trademark) TX-06-0049 (P-7B)” manufactured by Murata Manufacturing Co., Ltd. The water-based ink for ink jet recording of the present invention exerts the effects of the present invention sufficiently when applied to an ink head using PZT that easily corrodes that satisfies the condition (II), but the present invention is not limited to this. The present invention may be applied to an ink head using PZT that does not satisfy the condition (II).

  Next, an example of the configuration of an inkjet head using PZT will be described. In the following, a piezoelectric element and a piezoelectric actuator are synonymous. FIG. 1 shows a cross-sectional view of an example of an inkjet head using PZT, and FIG. 2 shows a plan view of a cavity unit of the inkjet head. In FIG. 1 and FIG. 2, the same code | symbol is attached | subjected to the same location.

  In the inkjet head 100 shown in FIG. 1, a plate-type piezoelectric actuator 20 is joined to a cavity unit 30 having a plurality of metal plates, and a flexible flat cable for connection to an external device is provided on the upper surface of the piezoelectric actuator 20. 24 is lap-joined. Then, the ink is ejected downward from the nozzle 50 opened on the lower surface side of the cavity unit 30.

  As shown in FIG. 1, the cavity unit 30 is composed of a total of six thin plates including a nozzle plate 31, a spacer plate 32, two manifold plates 33a and 33b, a base plate 34, and a cavity plate 35, respectively. It has a lap joint structure.

  Each of the plates 31 to 35 has a thickness of about 50 to 150 μm and is made of 42 alloy (nickel content: about 42%, iron content: about 58%) steel plate. In the nozzle plate 31, a large number of ink ejection nozzles 50 having a minute diameter (about 25 μm) are formed at minute intervals. The nozzles 50 are arranged in two rows in a staggered arrangement along the long side direction (the direction perpendicular to the paper surface of FIG. 1, the X direction of FIG. 2) of the nozzle plate 31.

  In the cavity plate 35, a plurality of pressure chambers 45 are arranged in two rows in a staggered arrangement along the long side direction of the cavity plate 35. In this example, each of the pressure chambers 45 is formed in an elongated shape in plan view, and the longitudinal direction thereof is formed along the short side direction of the cavity plate 35, and one end portion 45 a in the longitudinal direction communicates with the nozzle 50. The other end 45b communicates with a common ink chamber 49 described later.

  One end 45a of each pressure chamber 45 is connected to the nozzle plate via the base plate 34, the two manifold plates 33b and 33a, and the spacer plate 32 through the small-diameter communication holes 46 that are also formed in a staggered arrangement. 31 communicates with the nozzles 50.

  The base plate 34 adjacent to the lower surface of the cavity plate 35 is provided with a throttle portion 48 connected to the other end portion 45 b of each pressure chamber 45.

  The throttle portion 48 is formed with a small cross-sectional area so that ink is supplied from a common ink chamber 49 (to be described later) to the pressure chambers 45 and has a flow path resistance.

  The two manifold plates 33a and 33b are formed with two common ink chambers 49 extending through the plate thickness so as to extend along each row of the nozzles 50 along the long side direction. That is, as shown in FIG. 1, two manifold plates 33a and 33b are stacked, the upper surface thereof is covered with the base plate 34, and the lower surface is covered with the spacer plate 32, so that a total of two common ink chambers (manifold chambers) are formed. 49) is formed in a sealed state. Each common ink chamber 49 overlaps with a part of the pressure chamber 45 as shown in FIG. 2 along the row direction of the pressure chambers 45 (row direction of the nozzles 50) when viewed in plan from the stacking direction of the plates. It is long.

  One end of each common ink chamber 49 communicates with an ink supply source via an ink supply port (not shown).

  In the ink flow path from the ink supply port to the nozzle 50, the ink is supplied from the ink supply port to the common ink chamber 49 as an ink supply channel, and then passes through the throttle portion 48 of the base plate 34 to each pressure chamber 45. Distributed supply. Then, by driving the piezoelectric actuator 20, the ink passes from the inside of each pressure chamber 45 through the communication hole 46 and reaches the nozzle 50 corresponding to the pressure chamber 45.

  On the other hand, the piezoelectric actuator 20 has a structure in which a plurality of piezoelectric sheets 21 are laminated in the same manner as the known one disclosed in Japanese Patent Application Laid-Open No. 4-341833 etc., and each piezoelectric sheet having a thickness of about 30 μm. In the upper surface (wide surface) of the even-numbered piezoelectric sheet 21b from the bottom, narrow individual electrodes 23 are arranged in rows along the long side direction at locations corresponding to the pressure chambers 45 in the cavity unit 30. Is formed. A common electrode 22 common to the plurality of pressure chambers 45 is formed on the upper surface (wide surface) of the odd-numbered piezoelectric sheet 21a from the bottom.

  The plate-type piezoelectric actuator 20 having such a configuration is bonded and fixed to the cavity unit 30 with each individual electrode 23 corresponding to each pressure chamber 45 in the cavity unit 30. The flexible flat cable 24 having a wiring pattern connected to each electrode is fixed to the upper surface of the piezoelectric actuator 20.

  In the ink jet head shown in FIGS. 1 and 2, the piezoelectric sheet 21 a is in direct contact with the upper opening 51 of the pressure chamber 45. Therefore, when the ink is stored in the common ink chamber 49, the ink and the piezoelectric sheet 21a are in direct contact with each other in the pressure chamber 45, but the piezoelectric sheet 21a is not corroded by the ink.

  Next, the ink jet recording apparatus of the present invention will be described. The configuration of the ink jet recording apparatus of the present invention may be the same as that of a conventionally known ink jet recording apparatus, for example.

  FIG. 3 shows a configuration of an example of the ink jet recording apparatus of the present invention. As shown in the figure, the ink jet recording apparatus 1 includes four ink cartridges 2, an ink jet head 3, a head unit 4, a carriage 5, a drive unit 6, a platen roller 7, and a purge device 8. Including as a member. The inkjet head 3 is, for example, an inkjet head shown in FIGS.

  The four ink cartridges 2 contain one color each of four colors of yellow, magenta, cyan, and black. For example, each of the four color inks is the ink. The ink jet head 3 performs printing on a recording medium P such as recording paper. The head unit 4 includes the inkjet head 3. The four ink cartridges 2 and the head unit 4 are mounted on the carriage 5. The drive unit 6 reciprocates the carriage 5 in a linear direction. The platen roller 7 extends in the reciprocating direction of the carriage 5 and is disposed to face the ink jet head 3.

  The drive unit 6 includes a carriage shaft 9, a guide plate 10, two pulleys 11 and 12, and an endless belt 13. The carriage shaft 9 is disposed at the lower end of the carriage 5 and extends in parallel with the platen roller 7. The guide plate 10 is disposed at the upper end of the carriage 5 and extends in parallel with the carriage shaft 9. The two pulleys 11 and 12 are disposed between the carriage shaft 9 and the guide plate 10 at both ends of the carriage shaft 9. The endless belt 13 is stretched between the two pulleys 11 and 12.

  In the ink jet recording apparatus 1, when the pulley 11 is rotated forward and backward by driving the carriage motor 101, the carriage 5 joined to the endless belt 13 is moved along with the forward and reverse rotation of the pulley 11. Along the carriage shaft 9 and the guide plate 10, it reciprocates in a linear direction.

  The recording medium P is fed from a paper feed cassette (not shown) provided on the side of or below the ink jet recording apparatus 1. The recording medium P is introduced between the inkjet head 3 and the platen roller 7. Then, predetermined printing is performed on the recording medium P by the ink ejected from the inkjet head 3. Thereafter, the recording medium P is discharged from the inkjet recording apparatus 1. In FIG. 3, the paper feed mechanism and paper discharge mechanism of the recording medium P are not shown.

  The purge device 8 is provided on the side of the platen roller 7 so as to face the inkjet head 3 when the head unit 4 is at a reset position (in this example, the upper portion of the purge device 8). Has been placed. The purge device 8 includes a purge cap 14, a pump 15 and a cam 16, and an ink storage unit 17. The purge cap 14 covers a plurality of nozzles (not shown) of the inkjet head 3 when the head unit 4 is in the reset position. The pump 15 sucks out defective ink containing bubbles and the like accumulated in the ink jet head 3 by driving the cam 16. Thereby, recovery of the inkjet head 3 is achieved. The sucked defective ink is stored in the ink storage unit 17.

  A wiper member 19 is disposed adjacent to the purge device 8 at a position on the platen roller 7 side of the purge device 8. The wiper member 19 is formed in a spatula shape, and wipes the nozzle forming surface of the inkjet head 3 as the carriage 5 moves. In FIG. 3, a cap 18 covers a plurality of nozzles of the inkjet head 3 that are returned to the reset position when printing is completed in order to prevent ink from drying.

  In the ink jet recording apparatus 1 of this example, the four ink cartridges 2 are mounted on one carriage 5. However, the present invention is not limited to this. In the ink jet recording apparatus of the present invention, the four ink cartridges may be mounted on a plurality of carriages. Further, the ink cartridge may not be mounted on the carriage but may be arranged and fixed in the ink jet recording apparatus. In this aspect, for example, the ink cartridge and the head unit mounted on the carriage are connected by a tube or the like, and the ink is supplied from the ink cartridge to the head unit.

  The ink jet recording apparatus of the present invention may be the serial type ink jet recording apparatus shown in FIG. 3 or a line type ink jet recording apparatus.

  Next, in the corrosion inhibitor of the present invention and the inkjet head corrosion prevention method of the present invention, the types, blending amounts and forms of various components such as PZT and dyes to be prevented from corrosion are the water-based inks for inkjet recording of the present invention. Can be similar.

  Next, examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples.

[Examples 1 to 11 and Comparative Examples 1 to 15]
The ink composition components (Tables 1 and 2) were mixed uniformly. Then, the aqueous mixture for inkjet recording of Examples 1-11 and Comparative Examples 1-15 was filtered by filtering the obtained mixture with a cellulose acetate type membrane filter (pore diameter 1.00 μm) manufactured by Toyo Roshi Kaisha, Ltd. Obtained.

About the ink of an Example and a comparative example, flat-shaped test piece (The piezoelectric ceramic material "Piezotite (trademark) TX-06-0049 (P-7B)" by Murata Manufacturing Co., Ltd.); Size: 32.8mmx22 3 mm × 0.3 mm; surface area: 1495.94 mm ² ) was immersed in the inks of Examples and Comparative Examples under the following conditions (i) to (k), and the Pb elution amount from the test piece into each of the inks (PZT immersion test Pb elution amount) was measured using an ICP emission spectroscopic analyzer (ICPE-9000, manufactured by Shimadzu Corporation).

(I) Ink amount (Z) in Examples and Comparative Examples:
Z = surface area of the test piece (mm ² ) × 0.017 (g / mm ² ) (= 25.4 g)
(J) Ink temperature: 70 ° C.
(K) Immersion time: 5 days

When the sample piece was immersed in an EDTA · 2Na aqueous solution under the following conditions (e) to (h), the amount of Pb eluted from the test piece into the EDTA · 2Na aqueous solution was 200 to 290 ppm. It was.

(E) EDTA · 2Na aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) Amount of the EDTA · 2Na aqueous solution (Y):
Y = surface area of the test piece (mm ² ) × 0.017 (g / mm ² ) (= 25.4 g)
(G) Temperature of the EDTA · 2Na aqueous solution: 70 ° C
(H) Immersion time: 5 days

  Table 1 shows the ink compositions and measurement results of the examples. Table 2 shows the ink composition and measurement results of the comparative example. Further, FIG. 4 shows the relationship between the molar amount of Mg ions relative to the total molar amount of the dye and the Pb elution amount from the test piece based on the measurement results of Examples and Comparative Examples.

  As shown in Tables 1 and 2 and FIG. 4, the inks of Examples 1 to 11 in which the molar amount of Mg ions with respect to the total molar amount of the dye is 50 mol% or more have a small amount of Pb elution of 3.9 ppm or less. It was. On the other hand, the inks of Comparative Examples 1, 5, and 6 that did not contain Mg ions had a large amount of Pb elution. Further, the inks of Comparative Examples 2 to 4 containing sodium ions or potassium ions instead of Mg ions had a large amount of Pb elution. The inks of Comparative Examples 7 and 8 in which the molar amount of Mg ions relative to the total molar amount of the dye was less than 50 mol% had a large amount of Pb elution. Furthermore, instead of Mg ions, the inks of Comparative Examples 9 to 13 containing iron ions, aluminum ions, copper ions, or zinc ions produced precipitates in the ink immediately after the ink was prepared, thus improving the stability of the ink. It was inferior. Further, the inks of Comparative Examples 14 and 15 containing nickel ions or cobalt ions instead of Mg ions produced deposits on the ink the day after the ink was prepared, and the ink was inferior in stability.

FIG. 1 is a cross-sectional view showing an example of the configuration of an inkjet head using PZT. FIG. 2 is a plan view showing a cavity unit of the inkjet head in FIG. FIG. 3 is a diagram showing an example of the configuration of the ink jet recording apparatus of the present invention. FIG. 4 is a diagram showing the relationship between the molar amount of Mg ions relative to the total molar amount of dye and the amount of Pb eluted from the test piece in the examples of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Ink cartridge 3 Inkjet head 4 Head unit 5 Carriage 6 Drive unit 7 Platen roller 8 Purge device 9 Carriage shaft 10 Guide plate 20 Piezoelectric actuator 21 Piezoelectric sheet 22 Common electrode 23 Individual electrode 30 Cavity unit 31 Nozzle plate 32 Spacer Plates 33a, 33b Manifold plate 34 Base plate 35 Cavity plate 45 Pressure chamber 46 Communication hole 48 Restriction section 49 Common ink chamber 50 Nozzle 100 Inkjet head

Claims (6)

An aqueous ink for inkjet recording used in an inkjet recording apparatus,
The ink contains a dye that satisfies the following condition (I), water, and magnesium ions,
A water-based ink for inkjet recording, wherein the compounding amount of the magnesium ion is 50 mol% or more based on the total molar amount of the dye satisfying the condition (I).

Condition (I): When a lead zirconate titanate-containing sample satisfying the following condition (II) is immersed in an aqueous dye solution under the following conditions (a) to (d), the lead elution amount from the sample is 3 ppm to 10 ppm. is there.
(A) Concentration of the aqueous dye solution: 5.6 × 10 ⁻³ mol / L
(B) Amount of dye aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(C) Temperature of the dye aqueous solution: 70 ° C
(D) Immersion time: 5 days

Condition (II): When a lead zirconate titanate-containing sample is immersed in an ethylenediaminetetraacetic acid / disodium salt aqueous solution under the following conditions (e) to (h), the lead elution amount from the sample is 180 ppm to 300 ppm. .
(E) Ethylenediaminetetraacetic acid / disodium salt aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) Amount of ethylenediaminetetraacetic acid / disodium salt aqueous solution (Y): Y = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(G) Ethylenediaminetetraacetic acid / disodium salt aqueous solution temperature: 70 ° C.
(H) Immersion time: 5 days
Furthermore, the water-based ink for inkjet recording of Claim 1 which satisfy | fills the following conditions (III).

Condition (III): When a sample satisfying the condition (II) is immersed in the ink under the following conditions (i) to (k), the lead elution amount from the sample is 4 ppm or less.
(I) The ink amount (Z): Z = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(J) Ink temperature: 70 ° C.
(K) Immersion time: 5 days
The dye satisfying the condition (I) is C.I. I. Direct Yellow 86 and C.I. I. The water-based ink for ink jet recording according to claim 1, comprising at least one of direct yellow 132. An ink jet recording apparatus that includes an ink storage portion and an ink discharge means, and discharges ink stored in the ink storage portion by the ink discharge means,
An ink jet recording apparatus, wherein the ink containing portion contains the water-based ink for ink jet recording according to any one of claims 1 to 3. An anti-corrosion agent for preventing corrosion caused by dye ink of an inkjet head,
The dye ink contains a dye that satisfies the following condition (I):
The corrosion inhibitor includes magnesium ions,
The magnesium ion content is an amount that is 50 mol% or more based on the total molar amount of the dye that satisfies the following condition (I).

Condition (I): When a lead zirconate titanate-containing sample satisfying the following condition (II) is immersed in an aqueous dye solution under the following conditions (a) to (d), the lead elution amount from the sample is 3 ppm to 10 ppm. is there.
(A) Concentration of the aqueous dye solution: 5.6 × 10 ⁻³ mol / L
(B) Amount of dye aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(C) Temperature of the dye aqueous solution: 70 ° C
(D) Immersion time: 5 days

Condition (II): When a lead zirconate titanate-containing sample is immersed in an ethylenediaminetetraacetic acid / disodium salt aqueous solution under the following conditions (e) to (h), the lead elution amount from the sample is 180 ppm to 300 ppm. .
(E) Ethylenediaminetetraacetic acid / disodium salt aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) Amount of ethylenediaminetetraacetic acid / disodium salt aqueous solution (Y): Y = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(G) Ethylenediaminetetraacetic acid / disodium salt aqueous solution temperature: 70 ° C.
(H) Immersion time: 5 days
An inkjet head corrosion prevention method for preventing corrosion by dye ink of an inkjet head,
An ink jet head corrosion prevention method, wherein the dye ink contains a dye satisfying the following condition (I) and the corrosion inhibitor according to claim 5.

Condition (I): When a lead zirconate titanate-containing sample satisfying the following condition (II) is immersed in an aqueous dye solution under the following conditions (a) to (d), the lead elution amount from the sample is 3 ppm to 10 ppm. is there.
(A) Concentration of the aqueous dye solution: 5.6 × 10 ⁻³ mol / L
(B) Amount of dye aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(C) Temperature of the dye aqueous solution: 70 ° C
(D) Immersion time: 5 days

Condition (II): When a lead zirconate titanate-containing sample is immersed in an ethylenediaminetetraacetic acid / disodium salt aqueous solution under the following conditions (e) to (h), the lead elution amount from the sample is 180 ppm to 300 ppm. .
(E) Ethylenediaminetetraacetic acid / disodium salt aqueous solution concentration: 5.6 × 10 ⁻³ mol / L
(F) Amount of the ethylenediaminetetraacetic acid / disodium salt aqueous solution (X): X = surface area of the sample (mm ² ) × 0.017 (g / mm ² )
(G) Ethylenediaminetetraacetic acid / disodium salt aqueous solution temperature: 70 ° C.
(H) Immersion time: 5 days

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