JP2018034353A - Wiper blade, wiping unit, ink discharge unit and device for discharging ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiper blade for an ink jetting head that can keep ink discharge stability of an ink jetting head for a long term.SOLUTION: A wiper blade wipes over an ink discharge surface of an ink jetting head. The wiper blade for an ink jetting head includes the wiper blade formed of an elastic rubber. The elastic rubber has tan δ of peak temperature of -10°C or more and 10°C or less and a balanced swelling rate of 10% or less based on acetone.SELECTED DRAWING: None

Description

  The present invention relates to a wiper blade, a wiping unit, an ink discharge unit, and an apparatus for discharging ink.

  In recent years, the inkjet recording apparatus has been developed for industrial use, and the user is strongly demanded to achieve both high image quality and high productivity. Therefore, in order to increase the permeability and quick drying after the ink has landed on the medium, the surface energy of the ink is reduced or an organic solvent is added within a range that is not harmful to the human body.

In order to meet recent market demands, printed matter produced by an ink jet recording apparatus has increased demand for ink formulation designs that improve outdoor weather resistance and scratch resistance, that is, UV ink and solvent ink. However, the low molecular weight acrylate / methacrylate and organic solvent contained in these inks impose a heavy load on the wiper blade that is a surface cleaning member of the ink repellent film of the ink jet head.
In order to continue ejecting such ink with high stability, an ink-repellent film is provided on the surface of the ejection surface of the inkjet head, and a maintenance unit including a wiper blade for removing ink adhering to the surface is used in combination. .

  Further, there are various methods for cleaning the ink jet head and the wiper blade depending on the customer who uses the ink jet recording apparatus, and the fixed ink may be wiped off with an organic solvent that greatly swells rubber such as acetone. In the case of a rubber wiper such as EPDM that has been used in the past, it easily swells due to the ink component and the cleaning solvent, so that it is greatly worn by rubbing with the ink-repellent film or the SUS nozzle cover, or the edge is partially missing, etc. Ink wiping performance is degraded. That is, unwiping of ink occurs and discharge stability is lowered. However, if the resin film is used as a wiper simply because it does not swell, the resin film is too hard than the ink repellent film, and thus the ink repellent film is worn out at an early stage, which also lowers the discharge stability.

The maintenance unit that stabilizes the ejection state is equipped with a wiper blade that removes deposits on the ink-repellent film on the ink ejection surface, and has an appropriate rubber hardness to improve its removal function and extend its life. There are known a method of setting the range (Patent Document 1) and a method of performing an ink repellent treatment on the surface with a condensate of the same fluorine-containing hydrolyzable compound as the ink repellent film (Patent Document 2).
Further, there is known a method corresponding to UV ink or solvent ink by using a fluorine-based elastomer as a wiper blade (Patent Document 3).

  As the ink repellent film provided on the ejection surface, for example, a fluororesin having an ether bond in a heterocyclic structure such as Teflon (registered trademark) AF is used. As a method for forming the ink repellent film, a dipping method, a transfer method, a spray method is used. It is known that the coating method, spin coating method, wire bar coating method, thermal vapor deposition method, meniscus coating method, etc., and heating at a temperature above the glass transition point after film formation (Patent Documents 4 to 8).

  The present invention has been made in view of the above circumstances, and an object thereof is to maintain the ink ejection stability of an inkjet head for a long period of time.

In order to solve the above problems, the wiper blade for an ink jet head according to the present invention has the following configuration (1).
(1) A wiper blade for wiping the ink discharge surface of an inkjet head,
The wiper blade for an ink jet head, wherein the wiper blade is made of an elastic rubber, and the elastic rubber has a tan δ peak temperature of −10 ° C. or more and 10 ° C. or less and an equilibrium swelling ratio with acetone of 10% or less.

  By using the wiper blade for an inkjet head of the present invention, the ink ejection stability of the inkjet head can be maintained over a long period of time.

It is a figure which shows the arrangement | positioning relationship between an inkjet head and a wiping unit. It is a schematic diagram which shows the deformation | transformation state of the wiper blade in contact with a nozzle plate. It is a figure explaining the abrasion state of the wiper blade edge after long-term use. It is a schematic diagram explaining the mechanism in which edge missing occurs. It is explanatory drawing of the chipped state of a wiper blade edge. It is a figure which shows an example of the viscoelasticity measurement result of a low bridge | crosslinking density material. It is a figure which shows an example of the viscoelasticity measurement result of a high bridge | crosslinking density material. It is a plane explanatory view of the nozzle plate concerning the embodiment of the present invention. It is an expanded sectional explanatory view of one nozzle part. It is a plane explanatory view of a nozzle hole part used for explanation of the film thickness of an ink repellent film. It is an expanded sectional explanatory view of one nozzle part of a nozzle plate concerning an embodiment of the present invention. It is explanatory drawing with which it uses for description of an example of the manufacturing method of a nozzle plate. It is a figure explaining the apparatus for obtaining an ink repellent film by vacuum evaporation. This is a description of the state of the ink repellent film before baking. (A) is a SEM photograph of the cross section of the ink repellent film, and (b) is a SEM photograph of the surface of the ink repellent film. It is a figure explaining the state of the ink-repellent film after baking. (A) is a SEM photograph of the cross section of the ink repellent film, and (b) is a SEM photograph of the surface of the ink repellent film. It is explanatory drawing with which it uses for description of a wiping tolerance evaluation apparatus. FIG. 4 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of an example of the inkjet head according to the invention. It is sectional explanatory drawing of the nozzle arrangement direction (liquid chamber short direction) of the head. It is principal part plane explanatory drawing of an example of the apparatus which discharges the liquid which concerns on this invention. It is principal part side explanatory drawing of the apparatus. It is principal part plane explanatory drawing of the other example of the liquid discharge unit which concerns on this invention. It is a figure which shows the relationship between the ratio of TFE and PDD in tetrafluoroethylene perfluorodioxole (TFE / PDD), and a glass transition temperature.

The present invention relates to the wiper blade for an ink jet head described in the following (1). Since the following (2) to (10) are included as embodiments of the invention, these embodiments will be described together.
(1) A wiper blade for wiping the ink discharge surface of an inkjet head,
The wiper blade for an ink jet head, wherein the wiper blade is made of an elastic rubber, and the elastic rubber has a tan δ peak temperature of −10 ° C. or more and 10 ° C. or less and an equilibrium swelling ratio with acetone of 10% or less.
(2) The wiper blade for an inkjet head according to (1), wherein the equilibrium swelling ratio with acetone is 5% or less.
(3) The wiper blade for an inkjet head according to the above (1) or (2), wherein the coefficient of static friction of the wiper blade is 0.15 or less.
(4) A wiping unit including the wiper blade according to any one of (1) to (3) and a wiper blade support member that supports the wiper blade.
(5) An ink discharge unit including an ink jet head and a wiper blade for wiping the ink discharge surface of the ink jet head, wherein the wiper blade is the ink jet head according to any one of (1) to (3). Ink ejection unit, which is a wiper blade for use.
(6) The ink jet head has an ink repellent film formed on the ink ejection surface;
The ink ejection unit according to (5), wherein a static friction coefficient of the wiper blade is smaller than a static friction coefficient of the ink repellent film.
(7) The ink discharge unit according to (6), wherein the ink repellent film is a film containing a fluororesin having a fluorine-containing heterocyclic structure having an ether bond in a PTFE skeleton.
(8) The inkjet head includes a nozzle base material in which nozzle holes are formed, and the ink repellent film is formed on a surface of the nozzle base material,
The ink discharge unit according to (7), wherein the ink-repellent film is inclined in a direction in which a film thickness becomes thinner toward an edge side of the nozzle hole at an outer peripheral portion of the nozzle hole.
(9) An ink discharge apparatus comprising the ink discharge unit according to any one of (5) to (8) above.
(10) The apparatus for ejecting ink according to (9), wherein the ejected ink is an ink containing an acrylic / methacrylic monomer or is a solvent ink.

  In the above-described embodiment, the point that the elastic rubber having a single-layer structure is the wiper blade is the same as in the prior art, but the peak temperature of tan δ in the viscoelasticity measurement is in the range of −10 ° C. to 10 ° C. By selecting a rubber having an equilibrium swelling ratio of 10% or less, it becomes suitable as a wiper blade that removes ink containing a large amount of components that swell rubber greatly, such as UV ink and solvent ink, from the surface of the ink repellent film. The equilibrium swelling rate of acetone is preferably 5% or less.

At a temperature lower than the peak temperature of tan δ of the elastic rubber, the rubber is in a glass state, and at a temperature higher than the peak temperature, it is in a rubber state. As the crosslink density of the elastic rubber increases, the peak temperature shifts in a higher direction.
The use environment temperature of the wiper blade (for example, the temperature inside the ink discharge device) is 10 to 35 ° C. If the peak temperature is 10 ° C. or less, the rubber can be used in a rubber state at the use environment temperature. Followability can be obtained for surface irregularities.
The peak temperature of tan δ of ordinary rubber is −30 ° C., the lower limit value is defined as −10 ° C. as a condition in which crosslinking proceeds and swelling does not occur, and the upper limit value is 10 ° C. in order to obtain rubber elasticity at the use environment temperature. It was.

  Another market requirement for ink-jet prints is quick-drying, and the surface tension of the ink is decreasing in order to increase media permeability. When the dynamic surface tension becomes 25 mN / m or less, it cannot be easily repelled by a general silicone ink repellent film, and the ejection stability of the ink jet head cannot be obtained. To solve this problem, a dynamic surface tension of 20 mN / m or less is obtained by using a film containing a fluororesin having a PTFE skeleton having a fluorine-containing heterocyclic structure having an ether bond such as Teflon (registered trademark) AF. Ink repellency can be obtained even with this ink.

  Accordingly, a wiper blade made of rubber having an tan δ peak temperature in the range of −10 ° C. to 10 ° C. and an equilibrium swelling ratio of acetone of 10% or less, and an ether such as Teflon (registered trademark) AF By combining an ink repellent film containing a fluororesin having a PTFE skeleton with a fluorine-containing heterocyclic structure having a bond into an ink discharge device, a general water-based dye ink, water-based pigment ink, solvent ink, UV ink, The system can have a wide range of ink compatibility.

Next, the wiper blade will be described in detail with reference to FIGS.
FIG. 1 shows the inkjet head 404 and the wiping unit 50. The ink jet head 404 includes a nozzle plate 10 and an ink repellent film 40 formed on the surface of the nozzle plate 10. The wiping unit 50 includes a wiper blade 1 and a wiper blade support member 2 that supports the wiper blade 1.
FIG. 1 shows a state in which the wiper blade 1 is arranged so that ink can be properly removed from the surface of the nozzle plate 10 having an ink repellent film.

In general, elastic rubber is often used as the material of the wiper blade 1, and the elasticity moves the surface of the nozzle plate 10 while largely deforming as shown in FIG. 2 to remove ink. Another reason why the elastic rubber is suitable is that fine irregularities exist on the surface of the nozzle plate 10 and it is necessary to deform following the irregularities during rubbing.
However, rubber that is easily deformed generally has low cross-linking density, so it has low wear resistance in the first place and easily swells greatly with organic solvents, etc., so it has even lower wear resistance when used as a wiper blade for solvent ink or UV ink. The state continues, and the wiper blade edge is greatly worn at an early stage as shown in FIGS. 5 is a view of the wiper blade as viewed from the direction of the arrow shown in FIG. The contact pressure at which the wiper blade comes into contact with the ink repellent film becomes uneven, and ink streaks occur on the surface of the ink repellent film where there is no contact with the wiper blade. cause.

  In order to solve this, it is sufficient to increase the crosslinking density of the rubber. Generally, when the crosslinking density of the rubber is increased, the tan δ peak temperature also increases. However, if the crosslink density is increased to such an extent that the rubber elasticity is lost in an operating temperature range of the wiper, that is, an environment of 10 ° C. to 35 ° C., the fine unevenness on the surface of the nozzle plate cannot be followed as described above. In addition to not being able to remove the ink, the local high crosslink density portion may become harder than the ink repellent film and may be worn out such that the ink repellent film is scratched with a sharp needle.

  Further, when the elastic rubber having a greatly increased crosslink density is exposed to a solvent ink or UV ink for a long time, the low crosslink density portion (4 in FIG. 4) swells and wear resistance decreases, but the high crosslink density portion ( Since 5) in FIG. 4 is difficult to swell, when the intermolecular bond between the two is broken by wiping, a so-called “edge chipping” occurs in which the high crosslink density portion is largely dropped. Ink removal is impossible at the portion where the edge defect occurs, and the ink sticks to the surface of the nozzle plate in a streak-like manner, thus causing ejection bending.

  Therefore, it is not necessary to simply increase the crosslinking density, and it is also necessary that the peak temperature of tan δ in the viscoelasticity measurement is 10 ° C. or less. However, even if the crosslink density is increased until the tan δ peak temperature reaches 10 ° C. with general EPDM or the like, sufficient swelling resistance cannot be obtained for the organic solvent in the solvent ink.

  Therefore, the use of the wiper blade described above is possible by adjusting the cross-linking density so that the main material is fluorine rubber having high chemical resistance as the rubber and the tan δ peak temperature is in the range of −10 ° C. to 10 ° C. The wiper blade deforms following the fine irregularities on the surface of the nozzle plate 10 while maintaining rubber elasticity at the environmental temperature.

  It is preferable to use Viton or Kalrez from DuPont or Daiel from Daikin as the fluororubber, and to crosslink by peroxide vulcanization in order to further improve chemical resistance. By adjusting the amount of peroxide added, the glass transition temperature can be set in the range of −10 ° C. to 10 ° C.

Here, for the measurement of the glass transition temperature, dynamic viscoelasticity measurement is performed in a tensile mode using DMS7100 manufactured by SII NanoTechnologies in accordance with JIS K6394, whereby tan δ which is the ratio of storage elastic modulus to loss elastic modulus. The peak temperature can be obtained. 6 and 7 are diagrams showing examples of viscoelasticity measurement results. The measurement sample is obtained by cutting the elastic member of the wiper blade into a 40 × 10 × 2 mm strip or cutting the sheet after press molding. The measurement frequency was 1 Hz, the temperature increase rate was 3 ° C./min, and the measurement was performed from −30 ° C. to 50 ° C. As shown by the following formula, tan δ is a tangent loss that is a ratio between the storage elastic modulus and the loss elastic modulus.
tan δ = loss elastic modulus E ″ / storage elastic modulus E ′

Next, the equilibrium swelling rate with acetone was calculated according to JIS K6258 by completely immersing a rubber piece cut into 10 × 5 × 2 mm in acetone for 72 hours and changing the mass before and after.
Equilibrium swelling rate = (w2-w1) / w1 × 100 [%]
w1: Initial rubber piece mass [g]
w2: Rubber piece mass after immersion for 72 hours [g]

  The reason for choosing acetone from among organic solvents is that it is suitable for relative comparison of differences in cross-linking density because rubber easily swells, and an inkjet recording device that discharges solvent ink and UV ink is used. This is because the surface of the nozzle plate of the inkjet head and the wiper blade edge are wiped with a non-woven cloth soaked with acetone as a normal operation of the user. Therefore, it is preferable to evaluate using acetone as the condition with the largest load.

The static friction coefficient of the wiper blade is preferably smaller than the static friction coefficient of the ink repellent film formed on the ink ejection surface of the inkjet head. As a result, the sliding stress between the ink repellent film and the wiper blade is reduced, so that wear of both is suppressed, and the meniscus position of the nozzle hole does not change over a long period of time, thereby maintaining ejection stability. The static friction coefficient of the wiper blade is preferably 0.15 or less.
In general, as the crosslink density of an elastic rubber is higher, the stick-slip motion becomes smaller and the tackiness is lost, so that the friction coefficient of the surface becomes smaller.
Therefore, by using an elastic rubber having a high crosslinking density as the wiper blade, the frictional force when rubbing against the surface of the nozzle plate is reduced, and the effect of suppressing the progress of wear of both the wiper blade and the nozzle plate can be obtained.

Next, the ink repellent film of the nozzle plate 10 will be described with reference to FIGS.
The nozzle plate 10 includes a nozzle base material 20 in which holes (hereinafter referred to as “nozzle holes”) 21 to be nozzles 11 for discharging liquid are formed, an intermediate layer 30 formed on the surface of the nozzle base material 20, And an ink repellent film 40 formed on the surface of the liquid ejection surface.

  The nozzle substrate 20 is, for example, a metal flat plate member. As the nozzle substrate 20, a flat plate member made of stainless steel is used, but is not limited thereto. In the present embodiment, the nozzle hole 21 of the nozzle base material 20 includes a cylindrical portion 21a on the liquid discharge surface side and a truncated cone-shaped portion 21b on the opposite side to the liquid discharge surface side.

The intermediate layer 30 is configured by one or a plurality of layers such as a layer serving as a base of the ink repellent film 40, for example, a SiO ₂ layer or a silane coupling agent layer.

  The ink repellent film 40 is a film containing a fluororesin having a fluorine-containing heterocyclic structure having an ether bond in the PTFE skeleton (hereinafter also referred to as “fluororesin layer”). The ink repellent film 40 has a slope region 41 in which a slope 41 a that slopes in a direction in which the film thickness decreases toward the edge 11 a side of the nozzle 11 in the outer peripheral portion of the nozzle 11. Note that the slope 41a of the slope region 41 may have a cross-sectional shape that is slanted linearly or may be slanted in a curved shape.

  The region 42 other than the slope region except the slope region 41 of the ink repellent film 40 has a substantially constant film thickness and is flat. As described above, since the inclined region 41 is provided in the ink repellent film 40 in the outer peripheral portion of the nozzle 11, when the wiper blade is wiped by the wiper blade, the ink repellent film 40 is caught by the edge of the ink repellent film 40. Can be reduced or prevented. Thereby, the durability of the ink repellent film 40 can be improved.

  Further, the intermediate layer 30 is preferably a silane coupling agent layer in which the layer serving as the base of the ink repellent film 40 has an amino group. Thereby, high adhesion is obtained by the interaction between the amino group and the ink repellent film material.

Next, the ink repellent film in each of the above embodiments will be described.
The ink repellent film 40 is a film containing a fluororesin (hereinafter, also simply referred to as “fluororesin”) having a fluorine-containing heterocyclic structure having an ether bond in the PTFE skeleton. The fluororesin preferably has a glass transition point Tg of room temperature or higher.

The PTFE (polytetrafluoroethylene) skeleton is a main chain that repeats a structural unit of TFE (tetrafluoroethylene) represented by the following structural formula (1).

  The fluorine-containing heterocyclic structure having an ether bond is a structure of a 5- to 8-membered organic compound containing 1 to 2 oxygen atoms as a hetero atom in a chemical structural formula.

  As the fluororesin, it is preferable to use a fluororesin having a fluorine content of 50% by mass or more from the viewpoint of liquid repellency (contact angle). Further, the ratio of the ring structure in the main chain is preferably 20% by mass or more, more preferably 30% by mass from the viewpoint of the strength of the target film, solubility in a solvent, adhesion to a nozzle substrate, and the like. % Or more is preferable.

  Of the fluororesins, it is particularly preferable to use an amorphous fluororesin. Since the amorphous fluororesin is excellent in film strength, adhesion to a substrate, film uniformity, etc., the effects of the present invention can be further exhibited.

  Examples of the structural unit having a fluorine-containing heterocyclic structure having an ether bond include those represented by the following structural formulas (2) to (6).

  A fluororesin having a fluorine-containing heterocyclic structure having an ether bond of the structural unit represented by the structural formula (5) on the PTFE skeleton is issued by DuPont under the trade name Teflon (registered trademark) AF. Teflon (registered trademark) AF is a copolymer having a tetrafluoroethylene structure and a dioxole structure having a perfluoroalkyl group [TFE / PDD: tetrafluoroethylene-perfluorodioxole copolymer]. Excellent in terms of properties.

  The tetrafluoroethylene-perfluorodioxole copolymer is an amorphous fluororesin and a transparent resin. As the tetrafluoroethylene-perfluorodioxole copolymer, a suitably synthesized copolymer or a commercially available product may be used.

  The tetrafluoroethylene-perfluorodioxole copolymer has a glass transition point as shown in FIG. 22 as the ratio of the perfluoroidioxole copolymer (PDD) component to the tetrafluoroethylene (TFE) component increases. To rise. Commercially available are Teflon (registered trademark) AF1600 having a glass transition point of 160 ° C. and Teflon (registered trademark) AF2400 having a glass transition temperature of 240 ° C.

  In addition, a fluororesin having a fluorine-containing heterocyclic structure having an ether bond of the structural unit represented by the above structural formula (2) on the PTFE skeleton is issued by Solvay under the trade name Hyflon.

  A fluororesin having a fluorine-containing heterocyclic structure having an ether bond of the structural unit represented by the above structural formula (6) in the PTFE skeleton is a product name of Cytop CTX-105 or Cytop CTX-805. It is issued by the company.

  The average thickness of the ink repellent film 40 (fluorine resin layer) is preferably 1 μm to 3 μm.

  In order to obtain a smooth surface without unevenness on the surface of the nozzle substrate 20 affecting the surface of the fluororesin layer constituting the ink repellent film 40, the ink repellent film 40 should have a thickness of 1 μm or more. preferable. The ink repellent film 40 is preferably thin from the viewpoint of maintaining the shape of the nozzle 11 and the nozzle diameter. When the average thickness of the ink repellent film 40 is in the range of 1 μm to 3 μm, it is preferable from the viewpoint of wiping durability and the shape of the nozzle 11. The average thickness can be measured, for example, by a cross-sectional SEM.

  The arithmetic average roughness Ra of the ink repellent film 40 (fluororesin layer) is preferably 1.0 nm or less. When the average roughness Ra is 1.0 nm or less, the nozzle surface becomes extremely smooth, wiping residue due to wiping is reduced, and wear resistance is also excellent.

  The arithmetic average roughness Ra is defined as follows. In the section of length l, only the reference length is extracted from the roughness curve in the direction of the average line, the X axis is taken in the direction of the average line of the extracted portion, and the Y axis is taken in the direction of the vertical magnification. When the roughness curve is represented by y = f (x), the value obtained by the following equation (1) is expressed in micrometers (μm).

Next, an example of a method for manufacturing a wiper blade according to the present invention will be described.
As the elastic rubber material, it is preferable to use fluororubber.
By adding peroxide to fluororubber and performing press molding at a temperature of 150 to 300 ° C., the rubber is crosslinked and a rubber sheet having a predetermined thickness is molded.
The wiper blade is obtained by cutting or punching this into the shape of the wiper blade.

Next, an example of the nozzle plate manufacturing method according to the present invention will be described with reference to FIG.
In the base material preparation step of FIG. 12A, the mirror plate polishing step and the pre-step of the cleaning step are performed on the metal flat plate member that becomes the nozzle base material 20.
In addition, the nozzle base material 20 opens the nozzle hole 21 by press work to the metal flat plate member of length 30mm, width 15mm, and thickness 0.05mm, for example.

  As the metal flat plate member, stainless steel as a typical example of an iron-based alloy can be used. “Stainless steel” is a steel having a Cr content of 10.5% or more as described in JIS G0203: 2000 number 4201, and various steel types can be used.

  For austenite, Cr: 10.5 to 35% by mass, preferably 11 to 30% by mass, Ni: about 5 to 30% by mass, and for ferrite, Cr: about 10.5 to 35% by mass Preferably, a steel grade of about 15 to 30% by mass can be employed. For example, the steel grade prescribed | regulated to JISG4305: 2005 and JISG4312-1991 can be illustrated. Alternatively, stainless steel in which other alloy elements are added based on these standard steel types and various properties are improved can be used.

As the nickel-based alloy, a highly corrosion resistant Ni—Cr—Fe alloy containing Cr: 12 to 27 mass% and Fe: 5 to 18 mass% can be used. This type of alloy is known as an “Inconel alloy”.

  Then, the metal flat plate member is punched from the side opposite to the discharge surface, and burrs generated by the punching are removed by polishing or chemical etching.

Next, in the intermediate layer forming step of FIG. 12B, as the intermediate layer 30, an SIO ₂ film 31 is formed on the surface of the nozzle substrate 20 by sputtering or the like, and a tape is formed on the surface opposite to the liquid discharge surface side. After pasting 60, a silane coupling agent layer 32 is formed on the surface of the SIO ₂ film 31.

  Here, as the silane coupling agent, an aminosilane-based coupling agent is preferable, and 3-aminopropyltriethoxysilane is particularly preferable. Specifically, KBE-903 (Shin-Etsu Chemical), A1100 (momentive performance material), etc. are mentioned. The silane coupling agent layer 32 may be formed by any method such as a dipping method, a spin coating method, or a spray method.

  Since the aminosilane coupling agent has a good affinity between the heterocyclic ether moiety in the molecule of the fluororesin and the amino group, the fluororesin can be obtained by providing one amino group-containing silane coupling agent on the silica layer. The fixability of is greatly improved.

Thereafter, a vapor deposition film 44 to be the ink repellent film 40 shown in FIG. 12C is performed, and a vapor deposited film 44 in which an ink repellent material (denoted as AF) is vapor-deposited on the nozzle substrate 20 by a vapor deposition method. Is deposited. At this time, the vapor deposition film 44 to be the ink repellent film 40 is formed on the surface of the silane coupling agent layer 32 (the surface of the intermediate layer 30) on the nozzle substrate 20, as described above, as the ink repellent film 40. The fluororesin layer includes a fluororesin having ink repellency. As the fluororesin, a fluororesin having a fluorine-containing heterocyclic structure having an ether bond in the PTFE skeleton is used.

  As such a fluororesin, as described above, tetrafluoroethylene perfluorodioxole copolymer (Teflon (registered trademark) AF: manufactured by DuPont), Cytop CTX-105 (trade name, manufactured by Asahi Glass Co., Ltd.), Or Cytop CTX-805 (trade name, manufactured by Asahi Glass Co., Ltd.) is particularly preferable.

The fluororesin is heated to 350 to 420 ° C. under a high vacuum of 1.5 to 8.0 × 10 ⁻³ Pa, and the thickness of the vapor deposition film on the nozzle substrate 20 facing the vapor deposition source is Vacuum deposition is performed until the thickness becomes about 1 to 3 μm. For example, as shown in FIG. 13, the vacuum deposition is performed by disposing the deposition source 501 and the nozzle substrate 20 in the vacuum chamber 500.

Thereafter, as shown in FIG. 12D, a planarization process by annealing is performed.
The nozzle substrate 20 is not particularly heated, and a heat treatment is performed to bake (anneal) a film obtained by vapor deposition at a desired temperature at a temperature equal to or higher than the glass transition temperature of the fluororesin.

  The baking may be any method such as a convection drying furnace, a circulating air drying furnace, a flash annealing apparatus, a halogen lamp heater, or a vacuum dryer, but is preferably performed in a nitrogen atmosphere.

  By baking (annealing) at a temperature equal to or higher than the glass transition temperature of the fluororesin, the ink-repellent film (fluororesin layer) 40 is dense, has a smooth surface, and has a slope region 41 whose thickness decreases as the nozzle 11 is approached. It becomes.

FIG. 14A shows a cross-sectional SEM photograph and FIG. 14B shows a SEM photograph of the surface of the ink repellent film before baking.
Further, FIG. 15A shows a cross-sectional SEM photograph and FIG. 15B shows a SEM photograph of the surface of the ink repellent film after baking.

  In addition, as shown in FIG. 14A, the surface of the fluororesin film has pores 600 inside the film, and the film surface has a contact angle with respect to pure water of 129 ° and Ra = 8 nm. On the other hand, after baking, as shown in FIG. 15A, it became a tapered shape (slope shape) within the range of 40 nm from the edge 11a of the nozzle 11, and became a flat surface outside the periphery of 40 nm. .

  In addition, when performing the vapor deposition process which vapor-deposits a fluororesin on the nozzle base material 20, it is the same as when baking after the said vapor deposition also by vapor-depositing while heating the nozzle base material 20 at the temperature below glass transition temperature. The effect of this can be obtained.

  In addition, since the obtained film does not flow even at a temperature of 150 ° C. or higher, which is generally necessary for curing the adhesive, the liquid repellent regions other than the film forming region can be exposed to a high temperature environment after the deposition. As a result, a nozzle plate with high ejection reliability can be obtained without being contaminated with the material.

  Here, the film thickness of the ink repellent film 40 will be described with reference to FIG. FIG. 10 is an explanatory plan view of a nozzle hole portion used for the description.

  As shown in FIG. 10, the film thickness is measured at 20 points on a circumference CC that is 5 μm away from the edge 11a of the nozzle 11 in the direction opposite to the nozzle center 11o on the normal line from the edge 11a to the following equation (2). Let the arithmetic average of the population of film thicknesses obtained in step 1 be the average film thickness m.

  Then, the amount obtained by the following equation (3) is defined as dispersion, and the positive square root σ of this dispersion is taken as the standard deviation of the population (film thickness).

Here, the smaller the variation coefficient “thickness standard deviation σ / average film thickness m” means that the film thickness variation with respect to the film thickness is small and flat.
The average film thickness a on the circumference CC was measured with an ellipsometer at a spot diameter of φ10 μm at regular intervals around the circumference CC.

When the presence or absence of liquid wiping residue on the surface after wiping when this σ / m was changed was evaluated, σ / m = 0.03: none, σ / m = 0.06: none, σ / m = 0. 09: None, σ / m = 0.12: Existence, σ / m = 0.15: Existence In the case where there is no wiping residue of the liquid, the ejection bending of the discharged liquid does not occur.
Therefore, by setting σ / m <0.1, the injection bending can be reduced.

Next, another embodiment of the nozzle plate will be described based on an enlarged sectional view of the nozzle portion shown in FIG.
In the nozzle plate 10, the intermediate layer 30 is formed also on the inner wall surface of the nozzle hole 21 of the nozzle substrate 20, and the ink repellent film 40 is also formed on the inner wall surface of the nozzle 11.

  Here, the film thickness t2 of the ink repellent film 40b on the inner wall surface of the nozzle 11 (corresponding to the wall surface of the nozzle hole 21 of the nozzle substrate 20) is the film thickness t1 of the region 42 other than the slope region of the ink repellent film 40a. 1/10 or less (t2 / t1 <0.1).

The film thickness t2 of the ink repellent film 40a on the inner wall surface of the nozzle 11 increases the variation in nozzle diameter as the film thickness increases. Therefore, it is preferable that the ink repellent film 40a be thin in order to realize stable ejection. On the other hand, as the thickness t1 of the ink repellent film 40a on the liquid ejection surface side is generally thicker, the durability is improved.
The ink repellent film 40 having these opposite film thicknesses can be obtained by forming the film using, for example, a vapor phase method.
The film thickness can be measured by taking out a nozzle cross section by ion polishing and observing with SEM.

  The relationship between the film thickness t2 of the ink repellent film 40b on the inner wall surface of the nozzle 11 and the film thickness t1 of the region 42 other than the slope region of the ink repellent film 40a was evaluated. In the case where the ratio of t2 / t1 exceeds 0.1, the ink-repellent film is formed by the dip method, and then the dip liquid flowing into the nozzle is blown and opened by blowing air into the nozzle. A sample was obtained by drying.

  As a result, the presence / absence of the injection curve was t2 / t1 <0.05: none, t2 / t1 <0.10: none, and t2 / t1 ≧ 0.3: existence. From this, if t2 / t1 <0.10, the injection bending can be reduced or prevented.

  Next, an example of an ink jet head according to the present invention will be described with reference to FIGS. FIG. 17 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head, and FIG. 18 is a cross-sectional explanatory diagram in the nozzle arrangement direction (liquid chamber short direction) of the head.

  In this inkjet head, a nozzle plate 101 according to the present invention, a flow path plate 102, and a diaphragm member 103 made of a thin film member as a wall surface member are laminated and joined. And the piezoelectric actuator 111 which displaces the diaphragm member 103 and the frame member 120 as a common liquid chamber member are provided.

  The nozzle plate 101, the flow path plate 102, and the vibration plate member 103 communicate with the individual liquid chamber 106 through which the plurality of nozzles 104 that discharge the liquid communicate, the fluid resistance unit 107 that supplies the liquid to the individual liquid chamber 106, and the fluid resistance unit 107. And a liquid introduction part 108 leading to.

  Then, the liquid is supplied from the common liquid chamber 110 serving as the common flow path of the frame member 120 to the individual liquid chamber 106 through the supply port 109 formed in the diaphragm member 103 via the liquid introduction unit 108 and the fluid resistance unit 107. The supply port 109 may be provided with a filter.

The vibration plate member 103 is a wall surface member that forms the wall surface of the individual liquid chamber 106 of the flow path plate 102. The vibration plate member 103 has a three-layer structure, and a deformable vibration region (vibration plate) 130 is formed in a portion corresponding to the individual liquid chamber 106 in one layer on the flow path plate 102 side.
On the opposite side of the diaphragm member 103 from the individual liquid chamber 106, an actuator means for deforming the vibration region 130 of the diaphragm member 103 and a piezoelectric actuator 111 including an electromechanical transducer as a pressure generating means are arranged. Yes.

  This piezoelectric actuator 111 has a plurality of stacked piezoelectric members 112 bonded to a base member 113 with an adhesive, and the piezoelectric member 112 is grooved by half-cut dicing so that a required number of piezoelectric members 112 is provided. Columnar piezoelectric elements (piezoelectric columns) 112A and 112B are formed in a comb shape at predetermined intervals.

The piezoelectric elements 112A and 112B of the piezoelectric member 112 are the same, but are a piezoelectric element 112A that is driven by giving a drive waveform and a piezoelectric element 112B that is used as a mere support without giving a drive waveform.
The piezoelectric element 112 </ b> A is bonded to a convex portion 130 a that is an island-shaped thick portion formed in the vibration region 130 of the diaphragm member 103. Further, the piezoelectric element 112 </ b> B is joined to the convex portion 130 b which is a thick portion of the vibration plate member 103.
The piezoelectric member 112 is formed by alternately laminating piezoelectric layers and internal electrodes. The internal electrodes are each drawn out to the end face and provided with external electrodes, and are flexible for supplying a drive signal to the external electrodes of the piezoelectric element 112A. An FPC 115 as a wiring member is connected.

  The frame member 120 is formed by injection molding using, for example, epoxy resin or thermoplastic resin such as polyphenylene sulfite, and a common liquid chamber 110 to which liquid is supplied from a head tank or a liquid cartridge is formed.

  In this ink jet head, for example, the piezoelectric element 112A contracts by lowering the voltage applied to the piezoelectric element 112A from the reference potential, the vibration region 130 of the diaphragm member 103 is drawn, and the volume of the individual liquid chamber 106 expands. Thus, the liquid flows into the individual liquid chamber 106.

  Thereafter, the voltage applied to the piezoelectric element 112A is increased to extend the piezoelectric element 112A in the stacking direction, and the vibration region 130 of the vibration plate member 103 is deformed toward the nozzle 104 to contract the volume of the individual liquid chamber 106. Thereby, the liquid in the individual liquid chamber 106 is pressurized, and the liquid is ejected (jetted) from the nozzle 104.

Then, by returning the voltage applied to the piezoelectric element 112A to the reference potential, the vibration region 130 of the diaphragm member 103 is restored to the initial position, and the individual liquid chamber 106 expands to generate a negative pressure. The liquid is filled into the individual liquid chamber 106 from the liquid chamber 110. Therefore, after the vibration of the meniscus surface of the nozzle 104 is attenuated and stabilized, the operation proceeds to the next droplet discharge.
Note that the driving method of the head is not limited to the above example (pulling-pushing), and it is also possible to perform striking or pushing depending on the direction to which the driving waveform is given.

  Next, an example of an apparatus for ejecting ink according to the present invention will be described with reference to FIGS. FIG. 19 is an explanatory plan view of an essential part of the apparatus, and FIG. 20 is an explanatory side view of an essential part of the apparatus.

  This apparatus is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction by the main scanning moving mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 spans the left and right side plates 491A and 491B and holds the carriage 403 so as to be movable. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 spanned between the driving pulley 406 and the driven pulley 407.

  An ink jet head 404 is mounted on the carriage 403. For example, the inkjet head 404 ejects ink of each color of yellow (Y), cyan (C), magenta (M), and black (K). In addition, the inkjet head 404 is mounted with a nozzle row composed of a plurality of nozzles arranged in the sub-scanning direction orthogonal to the main scanning direction and the ejection direction facing downward.

  The ink stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the inkjet head 404 to the inkjet head 404.

  The supply mechanism 494 includes a cartridge holder 451 that is a filling unit for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Ink is fed from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

  This apparatus includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412 serving as transport means, and a sub-scanning motor 416 for driving the transport belt 412.

The conveyance belt 412 attracts the sheet 410 and conveys it at a position facing the inkjet head 404. The transport belt 412 is an endless belt and is stretched between the transport roller 413 and the tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction.
The transport belt 412 rotates in the sub-scanning direction when the transport roller 413 is rotationally driven by the sub-scanning motor 416 via the timing belt 417 and the timing pulley 418.
Furthermore, a maintenance / recovery unit 420 that performs maintenance / recovery of the ink-jet head 404 is disposed on the side of the conveyance belt 412 on one side of the carriage 403 in the main scanning direction.

  The maintenance / recovery unit 420 includes a wiping unit (see FIG. 1) having the wiper blade 422 according to the present invention, and a cap member 421 for capping the nozzle surface (surface on which the nozzle is formed) of the inkjet head 404, for example. Yes.

  The main scanning movement mechanism 493, the supply mechanism 494, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

In this apparatus configured as described above, the paper 410 is fed and sucked onto the transport belt 412, and the paper 410 is transported in the sub-scanning direction by the circular movement of the transport belt 412.
Therefore, by driving the inkjet head 404 according to the image signal while moving the carriage 403 in the main scanning direction, liquid is ejected onto the stopped paper 410 to form an image.
Thus, since this apparatus includes the wiper blade according to the present invention, a high-quality image can be stably formed.

Next, an example of the ink discharge unit according to the present invention will be described with reference to FIG. FIG. 21 is an explanatory plan view of a main part of the ink discharge unit.
The ink discharge unit includes at least an inkjet head and a wiper blade (wiping unit) according to the present invention. In the liquid discharge unit shown in FIG. 21, the side plate among the members constituting the ink discharge device. It is composed of a casing portion composed of 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, a maintenance / recovery unit 420, and an inkjet head 404. A supply mechanism 494 can be further attached to the ink discharge unit shown in FIG.

  In the present application, the “apparatus for ejecting ink” is an apparatus that includes an ink jet head or an ink ejection unit and that drives the ink jet head to eject ink. For example, an inkjet recording apparatus that forms an image on a recording material such as paper with ink is included.

The “device for ejecting ink” can include means for feeding, transporting, and ejecting an ink to which ink can be attached, a pre-processing device, a post-processing device, and the like.
In addition, the “device for ejecting ink” is not limited to an apparatus in which significant images such as characters and figures are visualized by the ejected ink. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  The above-mentioned “thing to which ink can adhere” means that ink can be attached at least temporarily and adheres and adheres, or adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic parts such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, unless specifically limited, includes everything to which ink adheres.

  Further, the “device for ejecting ink” includes both a serial type device that moves the ink jet head and a line type device that does not move the ink jet head, unless otherwise specified.

  The “inkjet head” is not limited to the pressure generating means used. For example, in addition to the piezoelectric actuator as described in the above embodiment (a multilayer piezoelectric element may be used), a thermal actuator using an electrothermal conversion element such as a heating resistor, a diaphragm and a counter electrode are included. An electrostatic actuator or the like may be used.

  In addition, the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling” and the like in the terms of the present application are all synonymous.

  The present invention will be described below in more detail based on examples, but the technical scope of the present invention is not limited to the following examples.

[Wiper blade]
Viton GBL-200 is used as the fluoro rubber, 5 parts of peroxide is added to 100 parts of rubber, and secondary vulcanization is performed by press molding at 180 ° C. for 1 hour and further at 250 ° C. for 5 hours. A 1 mm rubber sheet was obtained. This was cut to obtain a wiper blade.

[Nozzle substrate]
A metal flat plate member made of SUS316L having a length of 30 mm, a width of 15 mm, and a thickness of 0.05 mm was punched with a punch from the side opposite to the liquid discharge surface. The punch used for drilling has a cylindrical tip portion with a length of 10 μm and a diameter of 20 μm. The burrs generated on the liquid ejection surface side were removed by polishing.

  Thereby, the diameter of the cylindrical portion 21a on the ink discharge surface side is 20 μm, the diameter of the opening of the truncated cone-shaped portion 21b on the surface opposite to the ink discharge surface is 40 μm, and the height of the cylindrical portion 21a is 10 μm. The nozzle base material 20 in which 384 21s were formed was obtained.

[Ink repellent film]
Tetrafluoroethylene perfluorodioxole copolymer (Teflon (registered trademark) AF2400: manufactured by DuPont) is applied to the nozzle discharge surface side of the nozzle substrate 20 at a high vacuum of 1.5 to 8.0 × 10 ⁻³ Pa. Below, it heated at 350-420 degreeC and vacuum-deposited until the thickness of the vapor deposition film became about 1-3 micrometers in the part facing the vapor deposition source.
The obtained vapor-deposited film was baked at a temperature equal to or higher than the glass transition temperature of the fluororesin to form a fluororesin film that became a dense and smooth ink repellent film.

[Evaluation of wiping durability]
Wiping durability using the evaluation apparatus shown in FIG. 16 was evaluated. Specifically, the nozzle plate 1 is fixed with a fixing jig 602 and the wiper 611 is fixed to the fixing jig 612 in the container 601 containing the ink 610, and the wiping of the nozzle plate 1 to the surface of the ink repellent film 40 is performed. (Wiping) operation was performed.

  As the ink 610, SPC-0371 (UV ink) and SS-21 (solvent ink), which are ink-jet inks manufactured by Mimaki Engineering Co., Ltd., were used.

<Evaluation of ink adhesion / jet bending>
An ink jet head including the nozzle plates of Examples 1 to 10 and Comparative Examples 1 to 4 was configured and mounted on an IPSiO G515 manufactured by Ricoh Co., Ltd., and ink adhesion remaining after wiping and ejection bending were evaluated. Evaluation is performed by observing whether or not ink has adhered to the surface of the nozzle plate after 10,000 times of wiping durability test (after durability test), and by visually observing the printed nozzle check pattern. Evaluation was based on the presence or absence of bending.

  The evaluation results are shown in Tables 1 and 2. In Tables 1 and 2, “Δ” means that there is no problem in actual use, and “X” means that ink adhesion and bending that cannot withstand actual use has occurred. “◯” means less ink adhesion and ejection bending than “Δ”, and “更 に” means less ink adhesion and ejection bending than “◯”.

In any of Examples 1 to 10, after the wiping durability test, ink adhesion on the nozzle plate and bending of the nozzle check pattern have no problem in actual use.
On the other hand, in each of Comparative Examples 1 to 4, the ink-repellent film was greatly worn after wiping endurance, and the ink wiping function of the wiper blade was deteriorated. It is bent at a level that cannot withstand actual use.
In Comparative Example 1, since the wiper blade is a conventionally used EPDM rubber, it is swollen and greatly worn by the ink, and the ink wiping function deteriorates early.
In Comparative Example 2, a urethane rubber blade conventionally used as a cleaning blade in the field of electrophotography was used as a wiper blade. However, as in Example 1, since it was swollen by the ink component, it was greatly worn out, and the ink wiping function deteriorated early.
In Comparative Example 3, since the ink repellent film near the nozzle hole has a right-angled shape, the nozzle check pattern is bent at a level that does not endure actual use due to significant wear after the wiping durability test.
In Comparative Example 4, a wiper blade having a tan δ peak temperature exceeding 10 ° C. by increasing the degree of crosslinking of EPDM used in the past was used as a wiper blade. .

DESCRIPTION OF SYMBOLS 1 Wiper blade 2 Wiper blade support member 3 Wear part of wiper blade edge 4 Low bridge density part of elastic rubber 5 High bridge density part of elastic rubber 6 Chip part of wiper blade edge 7 Tan δ peak temperature 10 Nozzle plate 11 Nozzle 11a Edge 11o Nozzle Center 20 Nozzle base material 21 Nozzle hole 21a Cylindrical portion 21b of the nozzle hole on the liquid discharge surface side 21b Frustum-shaped portion on the opposite side to the liquid discharge surface side of the nozzle hole 30 Intermediate layer 31 SIO ₂ film 32 Silane coupling agent layer 40 Ink repellent film 40a Ink repellent film 40b on the liquid discharge surface side Ink repellent film on inner wall surface of nozzle 41 Inclined area of ink repellent film 41a Inclined surface of ink repellent film 42 Area other than inclined area of ink repellent film 44 Deposition film 50 Wiping unit 60 Tape 101 Nozzle plate 102 Channel plate DESCRIPTION OF SYMBOLS 103 Diaphragm member 104 Nozzle 106 Individual liquid chamber 107 Fluid resistance part 108 Liquid introduction part 109 Supply port 110 Common liquid chamber 111 Piezoelectric actuator 112 Piezoelectric member 112A, 112B Piezoelectric element 113 Base member 115 FPC
120 Frame member 130 Vibration region 130a, 130b Protruding portion 401 Guide member 403 Carriage 404 Inkjet head 405 Main scanning motor 406 Drive pulley 407 Driven pulley 408 Timing belt 410 Paper 412 Conveying belt 413 Conveying roller 414 Tension roller 416 Sub scanning motor 417 Timing belt 418 Timing pulley 420 Maintenance / recovery unit 421 Cap member 422 Wiper blade 440 Liquid discharge unit 441 Head tank 450 Liquid cartridge 451 Cartridge holder 452 Liquid supply unit 456 Tube 491A, 491B Side plate 491C Back plate 493 Main scanning movement mechanism 495 Supply mechanism 495 500 Vacuum chamber 501 Deposition source 600 Pore 601 Container 60 2 Fixing jig 610 Ink 611 Wiper blade 612 Fixing jig

Japanese Patent Application Laid-Open No. 09-0756517 JP 2006-159730 A Japanese Patent No. 5138475 JP-A-4-21959 JP 2008-188911 A JP 2010-5994 A JP 2010-260281 A JP-A-7-68765

Claims (10)

A wiper blade for wiping the ink discharge surface of an inkjet head,
The wiper blade for an inkjet head, wherein the wiper blade is made of an elastic rubber, and the elastic rubber has a peak temperature of tan δ of −10 ° C. or more and 10 ° C. or less and an equilibrium swelling ratio with acetone of 10% or less.   The wiper blade for an inkjet head according to claim 1, wherein the equilibrium swelling ratio with acetone is 5% or less.   The wiper blade for an ink jet head according to claim 1 or 2, wherein a coefficient of static friction of the wiper blade is 0.15 or less.   A wiping unit comprising the wiper blade according to any one of claims 1 to 3 and a wiper blade support member that supports the wiper blade.   An ink ejection unit comprising an inkjet head and a wiper blade that wipes an ink ejection surface of the inkjet head, wherein the wiper blade is an inkjet head wiper blade according to any one of claims 1 to 3. Discharge unit. The inkjet head has an ink repellent film formed on the ink ejection surface,
The ink discharge unit according to claim 5, wherein a static friction coefficient of the wiper blade is smaller than a static friction coefficient of the ink repellent film.   The ink ejection unit according to claim 6, wherein the ink repellent film is a film containing a fluororesin having a fluorine-containing heterocyclic structure having an ether bond in a PTFE skeleton. The inkjet head includes a nozzle base material in which nozzle holes are formed, and the ink repellent film is formed on a surface of the nozzle base material,
The ink discharge unit according to claim 7, wherein the ink repellent film is inclined in a direction in which a film thickness becomes thinner toward an edge side of the nozzle hole at an outer peripheral portion of the nozzle hole.   An apparatus for ejecting ink, comprising the ink ejection unit according to claim 5.   The apparatus for ejecting ink according to claim 9, wherein the ejected ink is an ink containing an acrylic / methacrylic monomer or is a solvent ink.