JP2019025911A - Liquid discharge head, liquid discharge head manufacturing method and recording method - Google Patents

Abstract

To provide a liquid discharge head that is configured to suppress a fixation of liquid to a liquid repellent layer provided on a surface of a discharge-port forming member over a long period of time.SOLUTION: The liquid discharge head has a discharge-port forming member 4 having a discharge port 5 for discharging liquid formed therein, in which a hardened layer 7 of a composition containing (a) a condensed product of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having cationic polymerizable group and (b) a compound having a cationic polymerizable group and an ethylene oxide chain (b) is provided on a surface of the discharge-port forming member 4.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liquid discharge head that discharges liquid, and more particularly, to an ink jet recording head that performs recording by discharging ink onto a recording medium.

  A liquid discharge head typified by an ink jet recording head generally includes a substrate provided with an energy generating element that generates energy used for discharging a liquid, and a discharge port forming member that forms a discharge port for discharging a liquid. It has.

  In this liquid discharge head, the surface state of the discharge port forming member greatly affects the liquid discharge performance. Therefore, by forming a liquid repellent layer on the surface of the discharge port forming member, adhesion of liquid is suppressed and the surface state is kept uniform. As such a liquid repellent layer, there is a layer containing a condensate of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group, as described in Patent Document 1. Can be mentioned.

  By the way, in recent years, various materials have been added to the ejected liquid to further improve the recording quality. As a result, the liquid adheres to the liquid repellent layer by a mechanism that has not been assumed in the past. There is a tendency. For example, an ink in which a high concentration pigment is dispersed may be used for the purpose of improving the recording quality. When the liquid discharge head is operated for a long time using such ink, the pigment in the ink is likely to aggregate and adhere due to the local distribution of the electrostatic charge on the surface of the liquid repellent layer.

  Therefore, Patent Document 1 describes that by adding a conductive compound such as carbon black to the liquid repellent layer, the liquid repellent layer is made non-charged and ink sticking is suppressed.

JP-T-2007-518587 JP 2011-206628 A

  However, the inventors have found that it is difficult to suppress the sticking of ink over a long period of time in a liquid repellent layer to which a conductive compound is added. The surface of the liquid repellent layer is regularly cleaned with a liquid and wiped with a rubber blade to remove ink. However, these operations may cause the conductive compound to fall off and reduce the antistatic properties. It is done.

  The object of the present invention is to solve the above problems. That is, by maintaining the antistatic property of the liquid repellent layer provided on the surface of the discharge port forming member of the liquid discharge head, the liquid discharge head in which the sticking of the liquid to the liquid repellent layer is suppressed over a long period of time and the production thereof Is to provide a method.

  Another object of the present invention is to provide a recording method in which sticking of a liquid to a liquid repellent layer of a liquid discharge head is suppressed and a high recording quality can be maintained over a long period of time.

  According to the present invention, there is provided a liquid discharge head having a discharge port forming member in which a discharge port for discharging a liquid is formed, and (a) a hydrolyzable silane having a fluorine-containing group on the surface of the discharge port forming member. A liquid discharge comprising a cured layer of a composition comprising a condensate of a compound and a hydrolyzable silane compound having a cationic polymerizable group, and (b) a compound having a cationic polymerizable group and an ethylene oxide chain A head is provided.

  Further, according to the present invention, a liquid containing a pigment dispersed with a charge dispersing agent or a resin, or a liquid containing a self-dispersing pigment in which a group having a charge is bonded to the surface directly or via an atomic group. A recording method for recording an image on a recording medium by discharging from the liquid discharge head is provided.

  Furthermore, according to the present invention, there is provided a method of manufacturing a liquid discharge head having a discharge port forming member in which a discharge port for discharging a liquid is formed, the step of forming a layer serving as the discharge port forming member; (A) a condensate of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group, and (b) a cationic polymerizable group and an ethylene oxide chain. And a step of forming a composition layer containing the compound, a layer that becomes the discharge port forming member, and a step of forming the discharge port in the layer of the composition. A method for manufacturing a head is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid discharge head in which the adhesion of the liquid to a liquid repellent layer is suppressed over a long period of time, and its manufacturing method are provided.

  Further, according to the present invention, there is provided a recording method in which the sticking of the liquid to the liquid repellent layer of the liquid ejection head is suppressed and a high recording quality can be maintained for a long period.

It is a typical perspective view showing an example of a liquid discharge head concerning one embodiment of the present invention. It is a typical sectional view showing an example of a liquid discharge head concerning one embodiment of the present invention. It is typical sectional drawing which shows the example of the manufacturing method of the liquid discharge head concerning one Embodiment of this invention.

  A liquid discharge head according to an embodiment of the present invention is a liquid discharge head having a discharge port forming member in which a discharge port for discharging a liquid is formed, and (a) a fluorine-containing group is formed on the surface of the discharge port forming member. Having a cured layer of a composition comprising a condensate of a hydrolyzable silane compound having a cationically polymerizable group and a hydrolyzable silane compound having a cationically polymerizable group, and (b) a compound having a cationically polymerizable group and an ethylene oxide chain. Features. The component (a) is a liquid repellent component, and the component (b) is a compound that imparts high antistatic properties to the liquid repellent layer by having an ethylene oxide chain. Since both the component (a) and the component (b) have a cationic polymerizable group, a compound having antistatic properties as the component (b) is condensed as a component (a) by the curing reaction of both. Incorporated into things. As a result, the antistatic compound does not easily fall off from the liquid repellent layer even by a liquid cleaning operation or a wiping operation on the surface of the liquid discharge head, and the antistatic property is highly durable.

  On the other hand, as described in Patent Document 2, in a liquid repellent layer containing a conductive compound as an antistatic compound, the conductive compound is detached by a liquid cleaning operation or a wiping operation on the surface of the liquid discharge head. Cheap. For this reason, the antistatic property gradually decreases with long-term use.

  In addition to these, compounds having antistatic properties include general surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants. The surfactant exhibits antistatic properties by adsorbing moisture in the air due to its high hydrophilicity. However, since the antistatic property is lost as soon as the water is removed by the liquid washing operation or the wiping operation on the surface of the liquid discharge head, the antistatic property is poor in sustainability. In order to maintain antistatic properties, it may be possible to add a large amount of a surfactant in advance. However, if a large amount of surfactant is added to the liquid repellent layer, the liquid repellency may be impaired.

  On the other hand, the liquid repellent layer of the liquid ejection head according to the embodiment of the present invention has a high antistatic property and is firmly incorporated into the liquid repellent layer as described above. It is possible to suppress sticking.

  Hereinafter, exemplary embodiments of the present invention will be specifically described with reference to the drawings.

  In the following, an embodiment of the present invention will be described by taking an inkjet recording head (hereinafter also referred to as a recording head) as an application example of the “liquid ejection head”, but the embodiment of the present invention is not limited to this. For example, the “liquid ejection head” can be mounted on an apparatus such as a printer, a copying machine, a facsimile having a communication system, a word processor having a printer unit, or an industrial recording apparatus combined with various processing apparatuses.

  In the present specification, “recording medium” refers to various media capable of recording such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, and the like. In addition, “recording” used in this specification means not only that an image having a meaning such as a character or a figure is given to a recording medium but also an image having no meaning such as a pattern. I mean. Further, “ink” or “liquid” used in the present specification should be broadly interpreted, and when applied on a recording medium, formation of images, patterns, patterns, etc. The liquid used for processing or processing of a recording medium shall be said. Here, the processing of the recording medium includes, for example, improvement in fixing property due to solidification or insolubilization of the coloring material in the ink applied to the recording medium, improvement in recording quality or color development, and improvement in image durability. Say.

<Recording head>
FIG. 1 is a schematic diagram illustrating an example of a recording head according to an embodiment of the present invention.

  The recording head has a substrate 1 on which energy generating elements 2 that generate energy used to eject liquid are formed in two rows at a predetermined pitch. In the substrate 1, a liquid supply port 3 is opened between two rows of energy generating elements 2. On the substrate 1, a discharge port 5 provided at a position facing each energy generating element 2 is formed by a discharge port forming member 4. The position of the discharge port 5 is not limited to the position facing the energy generating element 2 described above. The discharge port forming member 4 also functions as a flow channel forming member that forms individual flow channels 6 that communicate with the discharge ports 5 from the supply port 3. The substrate 1 is not particularly limited to its shape, material, etc., as long as it functions as a part of the members constituting the flow path 6 and can function as a support for the discharge port forming member 4. Can be used. In this embodiment, since the supply port 3 is formed by anisotropic etching as will be described later, a silicon substrate is used.

  This recording head is arranged so that the surface on which the discharge port 5 opens faces the recording surface of the recording medium. Then, the energy generated by the energy generating element 2 is applied to the ink filled in the flow path 6 through the supply port 3, and ink droplets are ejected from the ejection port 5 to adhere to the recording medium. To record. As the energy generating element 2, a piezoelectric element or the like can be used as an element that dynamically generates energy, such as an electrothermal conversion element (so-called heater) or the like that generates energy by heat.

  2A is a cross-sectional view of the recording head as viewed in a cross section passing through A-A ′ in FIG. 1 and perpendicular to the substrate 1. The recording head may be provided with a flow path forming member 8 that forms a wall of the flow path 6 between the substrate 1 and the discharge port forming member 4 as shown in FIG. Further, the shape of the discharge port 5 may be a so-called tapered shape in which the area of the cross section parallel to the substrate 1 becomes smaller from the substrate 1 side toward the discharge port 5.

  As shown in FIGS. 2A and 2B, a liquid repellent layer 7 is provided on the surface of the discharge port forming member 4. The liquid repellent layer 7 suppresses the ink ejected from the ejection port 5 from adhering to the surface of the recording head. The liquid repellent layer 7 is, as described above, (a) a condensate of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group (hereinafter also simply referred to as “condensate”). ) And (b) a compound having a cationically polymerizable group and an ethylene oxide chain. Below, each component which comprises the composition used as the liquid repellent layer 7 is described in detail.

(A) Condensation product of hydrolyzable silane compound having fluorine-containing group and hydrolyzable silane compound having cationic polymerizable group (a) The component is a liquid repellent component. The liquid repellent layer 7 obtained by curing the composition containing the component (a) has a siloxane skeleton (inorganic skeleton) generated from a hydrolyzable silane compound and a skeleton (organic skeleton) by curing a cationically polymerizable group. And an ether skeleton when an epoxy group is used. As a result, a so-called organic-inorganic bone hybrid cured material is obtained, and has high durability against the wiping operation on the surface of the recording head. Further, since the component (a) has a cationic polymerizable group, it has photosensitive characteristics corresponding to pattern formation by photolithography, and it is possible to form the discharge port 5 with high accuracy by patterning. .

  The fluorine-containing group in the hydrolyzable silane compound having a fluorine-containing group is preferably a group containing a perfluoroalkyl group or a perfluoropolyether group.

  As the hydrolyzable silane compound having a perfluoroalkyl group, a compound represented by the following formula (9) is preferably used.

_{CF 3 (CF 2) n -A} -SiX a Y 3-a (9)
(In the formula (9), A is a divalent organic group, X is a hydrolyzable substituent, Y is a non-hydrolyzable substituent, n is an integer of 0 or more and 20 or less, and a is 1 or more and 3 or less. (It is an integer.)
In formula (9), X is preferably a methoxy group or an ethoxy group. n is preferably an integer of 3 to 15, more preferably an integer of 5 to 10. A is preferably an organic group having 10 or less carbon atoms, more preferably a carbon such as a methylene group, an ethylene group, a propylene group, a butylene group, a methyleneoxy group, an ethyleneoxy group, a propyleneoxy group, and a butyleneoxy group. A divalent alkylene group or alkyleneoxy group having a number of 6 or less. Y is preferably an ethylene group.

Examples of the compound represented by the formula (9) include the following compounds:
_{CF 3 -C 2 H 4 -SiX 3} ;
_{C 2 F 5 -C 2 H 4} -SiX 3;
_{C 4 F 9 -C 2 H 4} -SiX 3;
_{C 6 F 13 -C 2 H 4} -SiX 3;
_{C 8 F 17 -C 2 H 4} -SiX 3;
_{C 10 F 21 -C 2 H 4} -SiX 3;
Is included. X is a methoxy group or an ethoxy group.

Among them, perfluoro decyl ethyl triethoxysilane _{(C 8 F 17 -C 2 H} 4 -Si (OC 2 H 5) 3) or tridecafluoro-1,1,2,2-tetrahydrooctyl triethoxysilane ( _{C 6 F 13 -C 2 H 4} -Si (OC 2 H 5) 3) is preferable.

  As the hydrolyzable silane compound having a perfluoropolyether group, any of compounds represented by the following formulas (10) to (13) is preferably used.

F-Rp-A-SiX _a Y _3-a (10)
(In the formula (10), Rp is a perfluoropolyether group, A is a divalent organic group, X is a hydrolyzable substituent, and Y is a non-hydrolyzable substituent. A is an integer of 1 to 3. .)
_{R 3-a X a Si-} A-Rp-A-SiX a Y 3-a (11)
(In Formula (11), R is a non-hydrolyzable substituent and may be the same as or different from Y. Rp, A, X, Y, and a are as defined in Formula (10). )

(In the formula (12), Z is a hydrogen atom or an alkyl group, Q ¹ is a divalent linking group, m is an integer of 1 or more and 4 or less. Rp, A, X, Y and a are represented by the formula (10 Is synonymous with

(In formula (13), n is 1 or 2. Q ² is a divalent linking group when n = 1, and a trivalent linking group when n = 2. Rp, A, X, Y and a is synonymous with Formula (10).)

  In the formulas (10) to (13), Rp is preferably a group represented by the following formula (14).

(In the formula (14), o, p, q and r are each an integer of 0 or more and 30 or less, and at least one of o, p, q and r is an integer of 2 or more.)

  In formula (14), o, p, q and r are each preferably an integer of 1 or more and 30 or less. Further, the total of o, p, q and r is preferably an integer of 3 or more and 10 or less from the viewpoint of liquid repellency and solubility in a solvent.

In formulas (10) to (13), the number of repeating units in Rp (the number of repeating units of each repeating unit) is preferably an integer of 1 to 30. Although it depends on the structure of the perfluoropolyether group, the number of repeating units is more preferably an integer of 3 or more and 20 or less. The average molecular weight (weight average molecular weight) of Rp is preferably 500 or more and 5000 or less, and more preferably 500 or more and 2000 or less. By average molecular weight of R _p of 500 or more, sufficient liquid repellency is obtained. Further, the average molecular weight of R _p of 5,000 or less, solubility in sufficient solvent is obtained. In many cases, the compound having a perfluoropolyether group is a mixture of compounds having different numbers of repeating units. Moreover, the average molecular weight of a perfluoropolyether group shows the average of the molecular weight of the sum total of the part shown by the repeating unit in said Formula (14). The average molecular weight is a value measured by GPC (gel permeation chromatography).

Examples of X include a halogen atom, an alkoxy group, an amino group, and a hydrogen atom. Among these, an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, and a propoxy group from the viewpoint that the group eliminated by the hydrolysis reaction does not inhibit the cationic polymerization reaction and the reactivity can be easily controlled. Is preferred. Examples of Y and R include an alkyl group having 1 to 20 carbon atoms and a phenyl group. Examples of the alkyl group for Z include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, and a propyl group. Examples of Q ¹ and Q ² include a carbon atom and a nitrogen atom. Examples of A include an alkylene group having 1 to 12 carbon atoms such as a methylene group, an ethylene group, a propylene group, a butylene group, a methyleneoxy group, an ethyleneoxy group, and a propyleneoxy group, or an alkyleneoxy group. These groups may have a substituent.

  Preferable specific examples of the hydrolyzable silane compound having a perfluoropolyether group include compounds represented by the following formulas (15) to (19).

(In the formula (15), s is an integer of 1 to 30, and m is an integer of 1 to 4.)

_{F- (CF 2 CF 2 CF 2} O) t -CF 2 CF 2 -CH 2 O (CH 2) 3 -Si (OCH 3) 3 (16)
(In formula (16), t is an integer of 1-30.)

_{(H 3 CO) 3 Si-} CH 2 CH 2 CH 2 -OCH 2 CF 2 - (OCF 2 CF 2) e - (OCF 2) f -OCF 2 CH 2 OCH 2 CH 2 CH 2 -Si (OCH ₃ ) ₃ (17)
(In formula (17), e and f are each an integer of 1-30.)

(In formula (18), g is an integer of 1-30.)

(In the formula (19), R _m is a methyl group or a hydrogen atom, and h is an integer of 1-30.)

  In formulas (15) to (19), the number of repeating units s, t, e, f, g, and h are each preferably 3 or more and 30 or less, and more preferably 5 or more and 20 or less. When it is 3 or more, liquid repellency is improved, and when it is 30 or less, solubility in a solvent is improved. In particular, when the condensation reaction is performed in a non-fluorinated solvent such as alcohol, s, t, e, f, g, and h are preferably 3 or more and 10 or less.

  Examples of commercially available hydrolyzable silane compounds having a perfluoropolyether group include “OPTOOL DSX” and “OPTOOL AES” manufactured by Daikin Industries, Ltd. “KY-108” and “KY-164” manufactured by Shin-Etsu Chemical Co., Ltd. "Novec1720" manufactured by Sumitomo 3M, "Fluorolink S10" manufactured by Solvay Solexis (both are trade names).

  Among these, the hydrolyzable silane compound having a perfluoropolyether group is preferably a compound represented by the above formula (19).

  As the hydrolyzable silane compound having a fluorine-containing group, one kind of the above-mentioned hydrolyzable silane compound may be used, or two or more kinds may be used in combination.

  The hydrolyzable silane compound having a cationic polymerizable group is preferably a hydrolyzable silane compound having an epoxy group or an oxetane group as the cationic polymerizable group. The cationically polymerizable group is more preferably an epoxy group from the viewpoint of availability and reaction control.

  As the hydrolyzable silane compound having a cationic polymerizable group, a compound represented by the following formula (20) is preferably used.

_{R c -SiX b Y 3-b} (20)
(In the formula (20), R _c is a non-hydrolyzable substituent having a cationic polymerizable group, X is a hydrolyzable substituent, Y is a non-hydrolyzable substituent, and b is an integer of 1 to 3. .)

  Furthermore, in addition to the hydrolyzable silane compound having a fluorine-containing group and the hydrolyzable silane compound having a cationic polymerizable group, in order to control the physical properties of the liquid repellent layer 7, alkyl-substituted, aryl-substituted or unsubstituted hydrolyzed Decomposable silane compounds are also preferably condensed.

Among these, as the alkyl-substituted or aryl-substituted hydrolyzable silane compound, a compound represented by the following formula (21) is preferably used.
R _a -SiX _(4-c) (21)
(In formula (21), R _a is a non-hydrolyzable substituent selected from the group consisting of substituted or unsubstituted alkyl and substituted and unsubstituted aryl, X is a hydrolyzable substituent, and c is 0 or more and 3 or less. (It is an integer.)

  As the compound represented by the formula (21), tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyl Tripropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxy Examples include silane.

  The composition of the condensation product, that is, the combination ratio of hydrolyzable silane compound having a fluorine-containing group, hydrolyzable silane compound having a cationic polymerizable group, and alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound is As appropriate. The addition amount of the hydrolyzable silane compound having a fluorine-containing group to the total hydrolyzable silane compound is preferably 0.5 mol% or more and 20 mol% or less, and particularly preferably 1 mol% or more and 10 mol% or less. When the addition amount is 0.5 mol% or more, high liquid repellency can be obtained, and when the addition amount is 20 mol% or less, the layer 12 that becomes a uniform liquid repellent layer can be obtained. If the surface of the layer 12 serving as the liquid repellent layer is sufficiently uniform, light when patterning the discharge ports 5 is not scattered on the surface of the layer 12, and the patterning accuracy is good.

  Furthermore, the combination ratio of the hydrolyzable silane compound having a cationically polymerizable group and the alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound is preferably 10: 1 to 1:10.

  The condensate is a hydrolyzable silane compound having a fluorine-containing group, a hydrolyzable silane compound having a cationic polymerizable group, and optionally hydrolyzing an alkyl-substituted, aryl-substituted or unsubstituted hydrolyzable silane compound. Prepared by running the reaction in the presence of water.

  The degree of condensation of the product can be appropriately controlled by the temperature, pH, etc. of the condensation reaction. Furthermore, it is possible to control the degree of condensation as a result of the hydrolysis reaction using a metal alkoxide as a catalyst for the hydrolysis reaction. As the metal alkoxide, aluminum alkoxide, titanium alkoxide, zirconium alkoxide and complexes thereof (acetylacetone complex and the like) are preferable.

(B) Compound having cationically polymerizable group and ethylene oxide chain The component (b) is a compound that imparts antistatic properties to the liquid repellent layer 7. Since the component (b) has an ethylene oxide chain, it has high conductivity, and can exhibit antistatic properties when added in a small amount. In addition, since the component (b) has a cationic polymerizable group, it reacts with the cationic polymerizable group in the condensate as the component (a) and is incorporated into the condensate. As a result, it is difficult for the compound having antistatic property to fall off from the liquid repellent layer 7 by the liquid washing operation or wiping operation on the surface of the liquid ejection head, and the antistatic property has high durability. Furthermore, the component (b) has a high affinity with a condensate of (a) a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group as a liquid repellent component. It is uniformly distributed on the surface of the head. As a result, unlike the case of the conductive compound, it is difficult to form a portion where the liquid repellent component does not exist locally, and it is difficult to inhibit the liquid repellent expression by the component (a).

  (B) The compound having a cationically polymerizable group and an ethylene oxide chain preferably has a cationically polymerizable group at the end, and preferably has at one end because the antistatic property is well expressed.

  Moreover, it is preferable that the length of the ethylene oxide chain in (b) component, ie, the number of the ethylene oxide units to comprise, is 2-10. When the number of ethylene oxide units is 2 or more, the antistatic property is particularly good. Further, when the number of ethylene oxide units is 10 or less, the liquid repellency of the obtained liquid repellent layer 7 is good because the liquid repellency of the component (a) is difficult to be inhibited.

  The cationic polymerizable group is preferably an epoxy group or an oxetane group, and is preferably the same as the cationic polymerizable group in the hydrolyzable silane compound having a cationic polymerizable group from the viewpoint of reactivity.

  As the compound having a cationically polymerizable group and an ethylene oxide chain, compounds represented by the following formulas (1) to (8) are suitably used.

(In the formulas (1) to (8), m is an integer of 0 or more, n is an integer of 2 or more, 10 or less, l and p are integers of 1 or more, R and R ₁ are hydrogen atoms or alkyl groups, R ₂ is An alkylene group.)

In formulas (1) to (8), examples of R and R ₁ include a hydrogen atom or an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, and a propyl group. R ₁ is preferably a hydrogen atom. Examples of R ₂ include alkylene groups having 1 to 4 carbon atoms such as methylene group and ethylene group. R ₂ is preferably a methylene group. m is preferably an integer of 0 or more and 2 or less, n is an integer of 2 or more and 6 or less, l is an integer of 1 or more and 3 or less, and p is preferably an integer of 1 or more and 3 or less.

  About the mixing ratio of (a) component in a composition, and (b) component, it can select suitably according to the kind of compound to be used. The content of the component (b) in the composition is 0.05% by mass or more, particularly 0.5% by mass or more, preferably 5% by mass or less, particularly 3% by mass with respect to the component (a). % Or less is preferable. When the content of the component (b) in the composition is 0.05% by mass or more with respect to the component (a), the antistatic property is good. Moreover, liquid repellency is favorable in content of (b) component in a composition being 5 mass% or less with respect to (a) component. Further, the number of moles of the component (b) in the composition is equal to or less than the mole number of the hydrolyzable silane compound having a fluorine-containing group, particularly preferably 50% or less, and preferably 10% or more. Is preferred. When the number of moles of the component (b) is equal to or less than the number of moles of the hydrolyzable silane compound having a fluorine-containing group, it is difficult to inhibit the liquid repellency due to the fluorine component. Good liquid repellency. Further, when the number of moles of the component (b) is 10% or more of the number of moles of the hydrolyzable silane compound having a fluorine-containing group, the antistatic property is good.

<Method for manufacturing recording head>
Next, an example of a method for manufacturing a recording head according to an embodiment of the present invention will be described with reference to FIG.

  FIG. 3 is a schematic cross-sectional view showing an example of the manufacturing method of the recording head according to the present embodiment according to the process, and the position of the cross-section is the same as FIG.

  First, as shown in FIG. 3A, a substrate 1 having an energy generating element 2 provided on the surface is prepared. The energy generating element 2 is connected to a control signal input electrode (not shown) for operating the element. Further, a protective layer (not shown) for the purpose of improving the durability of the energy generating element 2 and an adhesion improvement for the purpose of improving the adhesion between the discharge port forming member 4 (flow path forming member 8) and the substrate 1. Various functional layers such as layers (not shown) may be provided.

  Next, as shown in FIG. 3B, a photosensitive resin layer 9 is formed on the substrate 1 including the energy generating element 2. The photosensitive resin layer 9 is a so-called positive photosensitive resin layer. For the formation of the photosensitive resin layer 9, a general-purpose solvent coating method such as spin coating or slit coating can be applied.

  Next, as shown in FIG. 3C, the photosensitive resin layer 9 is patterned by a photolithography process to form a pattern 10 serving as a mold for the ink flow path 6. The pattern 10 is not only composed of one layer of positive photosensitive resin, but may be formed of a multilayer structure or a laminated structure of two or more layers of different types.

  As shown in FIG. 3D, a photosensitive resin layer 11 to be the discharge port forming member 4 is formed on the substrate 1 on which the flow path pattern 10 is formed in this way. The photosensitive resin layer 11 is a so-called negative photosensitive resin layer. The photosensitive resin layer 11 is formed by applying a composition containing a photosensitive resin by a method such as spin coating, roll coating, or slit coating. The composition preferably contains a cationic photopolymerization initiator and a photosensitive resin having a cationically polymerizable group. The photosensitive resin having a cationic polymerizable group is a component (a) in the layer 12 that becomes the liquid repellent layer by curing the photosensitive resin layer 11 and the layer 12 (described later) that becomes the liquid repellent layer together. It reacts with and binds to the cationically polymerizable group in the condensate. For example, when the cationically polymerizable group is an epoxy group, an ether bond is formed. As a result, the photosensitive resin layer 11 and the liquid repellent layer 12 are firmly bonded, and the resulting liquid repellent layer 7 is difficult to peel off from the discharge port forming member 4, and the liquid repellent layer 7 has high durability. It becomes like this. At this time, the cationically polymerizable group in the compound having an ethylene oxide chain as the component (b) also reacts with and binds to the cationically polymerizable group in the photosensitive resin layer 11. Therefore, the compound having an ethylene oxide chain is firmly bonded to the lower layer, and the antistatic property can be maintained for a long time.

  As the photosensitive resin, epoxy resin is used because it satisfies various performances such as high mechanical strength, adhesion to the base, ink resistance, and resolution for patterning the fine pattern of the discharge port 5. Can be suitably used.

  As the epoxy resin, for example, a reaction product of bisphenol A and epichlorohydrin having a molecular weight of about 900 or more, or a reaction product of bromobisphenol A and epichlorohydrin can be used. A reaction product of phenol novolak or o-cresol novolak and epichlorohydrin can be used. Also, polyfunctional epoxy having an oxycyclohexane skeleton described in JP-A-60-161973, JP-A-63-221121, JP-A-64-9216, and JP-A-2-140219. Examples thereof include resins. However, it is not limited to these compounds. The epoxy resin is preferably a compound having an epoxy equivalent of 2000 or less, more preferably an epoxy equivalent of 1000 or less. This is because if the epoxy equivalent exceeds 2000, the crosslinking density is lowered during the curing reaction, which may cause problems in adhesion and ink resistance.

  As the photocationic polymerization initiator for curing the epoxy resin, a compound that generates an acid by light irradiation can be used. Such a compound is not particularly limited, and for example, an aromatic sulfonium salt or an aromatic iodonium salt can be used. Examples of aromatic sulfonium salts include “TPS-102, 103, 105”, “MDS-103, 105, 205, 305”, “DTS-102, 103” (any of which are commercially available from Midori Chemical Co., Ltd.) Can also be illustrated as an example. Moreover, “SP-170, 172” (trade name) commercially available from Adeka Co., Ltd. can be mentioned. As aromatic iodonium salts, “DPI-105”, “MPI-103, 105”, “BBI-101, 102, 103, 105” (all trade names) commercially available from Midori Chemical Co., Ltd. are used. Can be preferably used. Moreover, the addition amount of a photocationic polymerization initiator can be made into arbitrary addition amounts so that it may become the target sensitivity. The addition amount of the photocationic polymerization initiator is preferably in the range of 0.5 to 5 wt% with respect to the epoxy resin. Moreover, you may add a wavelength sensitizer as needed, As this wavelength sensitizer, "SP-100" (brand name) marketed from Adeka Co., Ltd. is mentioned, for example.

  Furthermore, additives can be appropriately added to the above composition as necessary. For example, a flexibility imparting agent may be added for the purpose of lowering the elastic modulus of the epoxy resin, or a silane coupling agent may be added to obtain further adhesion to the base.

  Next, a composition containing the component (a) and the component (b) is applied onto the photosensitive resin layer 11 by a method such as a spin coat method, a roll coat method, or a slit coat method, A layer 12 is formed.

  Next, pattern exposure is performed through a mask (not shown), and development processing is performed to form the discharge ports 5 in the photosensitive resin layer 11 and the layer 12 that becomes the liquid repellent layer as shown in FIG. By exposing and developing the photosensitive resin layer 11 and the layer 12 serving as the liquid repellent layer at once, the cation polymerizable groups in both layers react to form the liquid repellent layer 7 having high durability and high antistatic properties. Can be obtained. At this time, the flow path pattern 10 can be simultaneously dissolved and removed. For this exposure, i-line is preferably used. An i-line having a center wavelength of 365 nm and a half width of about 5 nm is widely used. A commercially available i-line stepper can be used as the irradiation device.

  Next, as shown in FIG. 3F, an ink supply port 3 penetrating the substrate 1 is formed. The ink supply port 3 can be formed by anisotropic etching using a resin composition having etching solution resistance as an etching mask.

  Next, as shown in FIG. 3G, the ink flow path 6 is formed by removing the pattern 10. Further, heat treatment is performed as necessary, joining of a member (not shown) for supplying ink and electrical joining (not shown) for driving the energy generating element 2 are performed to complete the recording head.

<Recording method>
A recording method according to an embodiment of the present invention uses the recording head described above, and a liquid containing a pigment dispersed in a dispersing agent or resin having a charge, or a group having a charge on the surface is bonded directly or via an atomic group. The liquid containing the self-dispersing pigment is discharged from the recording head to record an image on a recording medium.

  The recording head can be used when various liquids are ejected, but can be suitably used particularly when an image is formed on a recording medium using an ink (liquid) containing a pigment. Inks containing pigments often use electrostatic repulsion in order to make the pigments stably present in the liquid. For example, an ink in which a pigment is dispersed with a dispersing agent or a resin having a charge, or an ink containing a self-dispersing pigment in which a charged group is bonded to the surface directly or through an atomic group. Since these pigment inks are charged, they are easily fixed to the liquid repellent layer 7 due to the local distribution of positive charges on the ejection surface on which the liquid repellent layer 7 is formed. If the recording head according to the embodiment of the present invention is used, the liquid repellent layer 7 has high antistatic properties for a long period of time even when a pigment ink having these charges is used. Ink sticking to the ink can be suppressed.

  The following examples further illustrate the present invention.

<Preparation of recording head>
Example 1
An ink jet head was produced according to the process shown in FIG.

First, as shown in FIG. 3A, an electrothermal conversion element (heater made of material HfB ₂ ) as the energy generating element 2 and a laminated film of SiN and Ta (non-heated film) at the site where the ink flow path 6 is formed. A silicon substrate 1 having the structure shown in FIG.

  Next, as shown in FIG. 3 (b), a positive photosensitive resin (ODUR manufactured by Tokyo Ohka Kogyo Co., Ltd.) is spin coated on the substrate 1, and baked at 120 ° C. for 3 minutes. Layer 9 was formed. The film thickness of the photosensitive resin layer 9 formed on the substrate 1 was 14 μm.

Subsequently, patterning of the photosensitive resin layer 9 was performed. As an exposure apparatus, Deep-UV exposure apparatus UX-3000 manufactured by Ushio Electric was used, and pattern exposure was performed at an exposure amount of 30000 mJ / cm ² . Thereafter, development was performed using methyl isobutyl ketone, and rinsing treatment was performed with isopropyl alcohol to form a pattern 10 having a film thickness (a in the figure) of 14 μm (FIG. 3 (c)).

  Next, as shown in FIG. 3 (d), a negative photosensitive resin composition for forming the discharge port forming member 4 was spin coated to form a photosensitive resin layer 11. As a negative photosensitive resin composition, the thing of the composition of following Table 1 was used. The unit of the blending amount in Table 1 is part by mass. The film thickness of the photosensitive resin layer 11 was 20 μm on the substrate 1 (b in the figure) and 10 μm on the pattern 10 (c in the figure).

  Next, a layer 12 serving as a liquid repellent layer was formed on the photosensitive resin layer 11 by slit coating. The condensate which will be described later is used as the condensate which is the component (a) in the layer 12, and the compound having a cationic polymerizable group and an ethylene oxide chain which is the component (b) in the composition is represented by the following formula (22). 0.24 g (0.0024 mol) of the compound obtained was used.

The condensate was synthesized as follows. γ-glycidoxypropyltriethoxysilane 27.84 g (0.1000 mol), methyltriethoxysilane 17.83 g (0.1000 mol), perfluorodecylethyltriethoxysilane 3.35 g (0.0047 mol), water 16. 58 g and 30.05 g of ethanol were stirred at room temperature for 5 minutes and then refluxed for 48 hours to obtain a condensate of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group. It was. Here, the theoretical solid content concentration calculated by hydrolyzing and condensing all the hydrolyzable groups of the hydrolyzable silane compound was 28%. ²⁹ Si-NMR was measured and the condensation degree of the condensate was calculated and found to be 80%.

Next, as shown in FIG. 3E, the photosensitive resin layer 11 and the layer 12 were patterned in order to form the discharge ports 5. Using an i-line stepper FPA-3000i5 + manufactured by Canon Inc. as an exposure apparatus, pattern exposure was performed at an exposure amount of 5000 J / m ² . Thereafter, development with methyl isobutyl ketone and rinsing with isopropyl alcohol were performed, followed by heat treatment at 100 ° C. for 60 minutes. The discharge port 5 was formed as described above. In the present embodiment, a discharge port pattern mask having a circular shape corresponding to the discharge port pattern was used as the discharge port pattern mask during exposure. Further, even after the exposure and development for forming the discharge port 5, the pattern 10 was not developed and remained in a state in which the shape was maintained.

  Next, an etching mask (not shown) was formed on the back surface of the substrate 1, and an ink supply port 3 was formed by anisotropic etching as shown in FIG. At this time, a protective film (OBC manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied in advance on the photosensitive resin layer 11 for the purpose of protecting the discharge port forming surface from the etching solution.

Next, after dissolving and removing the protective film with xylene, the entire surface was exposed at an exposure amount of 250,000 mJ / cm ² through a negative resist using a Deep-UV exposure apparatus UX-3000 manufactured by USHIO INC. Was solubilized. Subsequently, the pattern 10 was dissolved and removed by immersion in methyl lactate while applying ultrasonic waves (FIG. 3 (g)).

  A recording head was produced as described above.

(Example 2)
A recording head was prepared in the same manner as in Example 1 except that 0.27 g (0.0024 mol) of the compound represented by the following formula (23) was used as the component (b).

(Example 3)
A recording head was prepared in the same manner as in Example 1 except that 0.48 g (0.0024 mol) of the compound represented by the following formula (24) was used as the component (b).

Example 4
A recording head was prepared in the same manner as in Example 1 except that 0.55 g (0.0024 mol) of the compound represented by the following formula (25) was used as the component (b).

(Example 5)
A recording head was prepared in the same manner as in Example 1 except that 0.64 g (0.0024 mol) of the compound represented by the following formula (26) was used as the component (b).

(Example 6)
A recording head was prepared in the same manner as in Example 1 except that the amount of the compound represented by formula (22) as the component (b) was changed to 0.54 g (0.0048 mol).

(Example 7)
A recording head was prepared in the same manner as in Example 1 except that the amount of the compound represented by formula (22) as the component (b) was changed to 0.027 g (0.00024 mol).

(Comparative Example 1)
An ink jet recording head was prepared in the same manner as in Example 1 except that carbon black 5 wt% (based on component (a)) was used instead of component (b).

(Comparative Example 2)
A recording head was prepared in the same manner as in Example 1 except that 0.25 g (0.0024 mol) of the compound represented by the following formula (27) was used instead of the component (b).

<Evaluation>
The following characteristics were evaluated for the recording head produced as described above. Each characteristic and its evaluation method are shown below, and the results are shown in Table 2 below.

(Pure water contact angle)
Using a micro contact angle meter (product name: DropMeasure, manufactured by Microjet Co., Ltd.), the dynamic receding contact angle θr with respect to pure water was measured. The measurement was carried out after wiping the pigment ink once on the surface of the discharge port forming member 4 and washing with water, and after performing wiping operation 5000 times using a blade of hydrogenated nitrile rubber while spraying the pigment ink on the surface. And conducted. In Table 2, each measurement result is shown as “initial” and “after endurance”. Judgment criteria are as follows.
Criteria for pure water contact angle A: 95 ° or more B: 80 ° or more and less than 95 ° C: 70 ° or more and less than 80 ° D: 70 ° or less

(Fixation)
The surface of the discharge port forming member 4 was observed using an optical microscope to confirm the presence or absence of ink sticking. The evaluation of the fixation was carried out in the same way as the measurement of the pure water contact angle as described above, and after the endurance. Judgment criteria are as follows.
Adherence determination criteria A: No ink adhering B: Ink adhering around the ejection ports is seen in less than 10% of the number of ejection ports.
C: Ink sticking around the ejection port is observed at 10% or more of the number of ejection ports.

  As shown in Comparative Example 1, when carbon black was used as the compound having antistatic properties, the ink adhered to the liquid repellent layer on the nozzle surface after durability. This is presumably because the carbon black dropped off from the liquid repellent layer. Further, the surface of the discharge port forming member was not sufficiently liquid repellent from the beginning. This is presumably because the addition of a large amount of carbon black inhibits the expression of liquid repellency due to the component (a). In Comparative Example 1, the reason why the pure water contact angle is higher after the endurance than in the initial stage is considered to be that the original performance of the liquid repellent layer was obtained by the carbon black falling off from the liquid repellent layer. .

  In Comparative Example 2, the initial pure water contact angle and the adhesion evaluation were good, but the ink adhesion was observed after the endurance. This is presumably because the polyethylene oxide compound did not have a cationic polymerizable group, and the polyethylene oxide compound was dropped from the liquid repellent layer. Unlike Comparative Example 1, the pure water contact angle at the initial stage of the liquid repellent layer is high because the polyethylene oxide compound has a high antistatic property in the first place, so the amount added to the liquid repellent layer is small. This is because it is difficult to inhibit the expression of liquid repellency.

  In contrast to these comparative examples, in Examples 1 to 5, the pure water contact angle of the liquid repellent layer was high both in the initial stage and after the durability, and no ink was fixed to the liquid repellent layer.

  In addition, in Example 6, it turns out that the pure water contact angle falls a little by increasing the addition amount of a polyethylene oxide type compound compared with Example 1. FIG. Furthermore, in Example 7, compared with Example 1, it turns out that antistatic property is somewhat inferior by reducing the addition amount of a polyethylene oxide type compound. However, in both cases, the contact angle of pure water and the antistatic property are at a relatively high level, and there are no practical problems.

  As described above, according to the present embodiment, the liquid repellent layer can be fixed to the liquid repellent layer for a long period of time by maintaining the antistatic property of the liquid repellent layer provided on the surface of the discharge port forming member of the liquid discharge head. Be suppressed over.

4 Discharge port forming member 5 Discharge port 7 Liquid repellent layer

Claims (15)

A liquid discharge head having a discharge port forming member in which a discharge port for discharging liquid is formed,
(A) a condensate of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group; and (b) a cationic polymerizable group and an ethylene oxide chain on the surface of the discharge port forming member. A liquid ejection head comprising a cured layer of a composition comprising:   The liquid discharge head according to claim 1, wherein the compound (b) having a cationic polymerizable group and an ethylene oxide chain has a cationic polymerizable group at one end. 2. The liquid discharge head according to claim 1, wherein (b) the compound having a cationic polymerizable group and an ethylene oxide chain is any one of compounds represented by the following formulas (1) to (8).








(In the formulas (1) to (8), m is an integer of 0 or more, n is an integer of 2 or more, 10 or less, l and p are integers of 1 or more, R and R ₁ are hydrogen atoms or alkyl groups, R ₂ is An alkylene group.)   4. The liquid discharge head according to claim 1, wherein the discharge port forming member is a cured product of a composition including a photocationic polymerization initiator and a photosensitive resin having a cationic polymerizable group. 5.   5. The liquid ejection head according to claim 1, wherein the fluorine-containing group of the hydrolyzable silane compound having a fluorine-containing group is a perfluoroalkyl group or a perfluoropolyether group.   The number of moles of the compound (b) having a cationically polymerizable group and an ethylene oxide chain in the composition is equal to or less than the number of moles of the hydrolyzable silane compound having the fluorine-containing group. The liquid discharge head according to any one of the above.   The content of the compound (b) having a cationically polymerizable group and an ethylene oxide chain in the composition is as follows: (a) a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane having a cationically polymerizable group. 7. The liquid discharge head according to claim 1, wherein the content is 0.05% by mass or more and 3% by mass or less based on the condensate with the compound.   A liquid containing a pigment dispersed in a dispersing agent or a resin having a charge, or a group having a charge on the surface, directly or via an atomic group, using the liquid discharge head according to any one of claims 1 to 7. A recording method for recording an image on a recording medium by discharging a liquid containing a self-dispersing pigment bonded together from the liquid discharge head. A method of manufacturing a liquid discharge head having a discharge port forming member in which a discharge port for discharging a liquid is formed,
Forming a layer to be the discharge port forming member;
On the layer serving as the discharge port forming member, (a) a condensate of a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane compound having a cationic polymerizable group, and (b) a cationic polymerizable group Forming a layer of the composition comprising a compound having an ethylene oxide chain;
Forming the discharge port in the layer to be the discharge port forming member and the layer of the composition;
A method of manufacturing a liquid discharge head, comprising:   The method for manufacturing a liquid discharge head according to claim 9, wherein the compound (b) having a cationic polymerizable group and an ethylene oxide chain has a cationic polymerizable group at one end. The method for manufacturing a liquid discharge head according to claim 9, wherein (b) the compound having a cationic polymerizable group and an ethylene oxide chain is any one of compounds represented by the following formulas (1) to (8).








(In the formulas (1) to (8), m is an integer of 0 or more, n is an integer of 2 or more, 10 or less, l and p are integers of 1 or more, R and R ₁ are hydrogen atoms or alkyl groups, R ₂ is An alkylene group.)   The method for manufacturing a liquid discharge head according to claim 9, wherein the fluorine-containing group of the hydrolyzable silane compound having a fluorine-containing group is a perfluoroalkyl group or a perfluoropolyether group.   The number of moles of the compound (b) having a cationically polymerizable group and an ethylene oxide chain in the composition is equal to or less than the mole number of the hydrolyzable silane compound having the fluorine-containing group. The method for producing a liquid discharge head according to any one of the above.   The content of the compound (b) having a cationically polymerizable group and an ethylene oxide chain in the composition is as follows: (a) a hydrolyzable silane compound having a fluorine-containing group and a hydrolyzable silane having a cationically polymerizable group. The method for manufacturing a liquid ejection head according to claim 9, wherein the content is 0.05% by mass or more and 3% by mass or less based on a condensate with the compound. The layer to be the discharge port forming member contains a photocationic polymerization initiator and a photosensitive resin having a cationic polymerizable group, and in the step of forming the discharge port, the layer to be the discharge port forming member and the composition The method of manufacturing a liquid discharge head according to claim 9, wherein the discharge port is formed by collectively exposing and developing the layer.