JP2012131177A - Liquid injection head, and liquid injection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection head that can improve print quality by enhancing landing accuracy of droplets, and to provide a liquid injection apparatus.SOLUTION: The liquid injection head includes: a pressure generation unit that generates a pressure change to a pressure generation chamber and liquid within the pressure generation chamber; a nozzle plate 35 where nozzle openings 34a, 34b connected to the pressure generation chamber are formed; and water repellent film 50 that is provided at the side of a liquid injection surface S of the nozzle plate 35. The plurality of nozzle openings 34a, 34b are provided for one pressure generation chambers. The water repellent film 50 is provided to different depths from the liquid injection surface S in the plurality of nozzle openings 34a, 34b for the one pressure generation chambers.

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject liquid from nozzle openings, and more particularly to an ink jet recording head and an ink jet recording apparatus that eject ink as liquid.

  An ink jet recording head which is an example of a liquid ejecting head has been proposed in which two or more nozzle openings are provided for one pressure generating chamber (see, for example, Patent Document 1).

  Here, the relationship between the ink weight of the ink droplets landed on the recording medium and the dot diameter (diameter) is half the dot diameter even if the ink weight is half that of the predetermined ink weight. The dot diameter is larger than half. Further, if the ink weight is small, the amount of ink penetrating the recording medium is small and drying is quick.

  From this, it is possible to increase the optical density (OD value; Optical Density) of the printed matter by providing a plurality of nozzle openings for one pressure generating chamber and ejecting ink droplets with a reduced ink weight from the nozzle openings. it can. Further, compared to the case where only one nozzle opening is provided for the pressure generating chamber, the ink consumption can be reduced even with the same optical density.

JP 2002-331658 A

  However, if ink droplets are ejected simultaneously from a plurality of (for example, two) nozzle openings, the plurality of ink droplets fly away in the direction away from each other due to the influence of airflow or electrostatic force (Coulomb force) during flight, and the landing position is There is a problem that the printing quality is deteriorated due to the deviation.

  Such a problem exists not only in an ink jet recording head but also in a liquid ejecting head that ejects liquid other than ink.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head and a liquid ejecting apparatus that can improve the landing accuracy of droplets ejected from a nozzle opening and improve printing quality.

An aspect of the present invention that solves the above problems includes a pressure generating chamber, pressure generating means for causing a pressure change in the liquid in the pressure generating chamber, a nozzle plate having a nozzle opening communicating with the pressure generating chamber, A liquid ejecting head including a water repellent film provided on the liquid ejecting surface side of the nozzle plate, wherein a plurality of nozzle openings are provided for one pressure generating chamber, In the liquid ejecting head, the water repellent film is provided from the liquid ejecting surface to different depths on the inner surfaces of the plurality of nozzle openings with respect to the generation chamber.
In this aspect, the depth of the liquid meniscus from the liquid ejection surface formed in each nozzle opening can be made different in the plurality of nozzle openings communicating with one individual flow path. As a result, since the liquid ejection start positions (positions relative to the liquid ejection surface) of the plurality of nozzle openings communicating with one individual flow path can be set to different positions, when the ejected liquid flies, Fly without lining up. For this reason, it is possible to suppress the liquid from being bent and flying due to the influence of the air current and the influence of the Coulomb force, improve the accuracy of the landing position on the recording medium, and improve the printing quality.

  Here, it is preferable that the water-repellent film is formed by eutectoid plating. According to this, the water repellent film can be formed easily and at low cost.

  The water repellent film may have a metal alkoxide molecular film. According to this, it is possible to form a relatively thin water-repellent film and improve the abrasion resistance and liquid repellency.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
In this aspect, a liquid ejecting apparatus with improved print quality can be realized.

FIG. 3 is an exploded perspective view of the recording head according to the first embodiment. FIG. 3 is a plan view of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of the recording head according to the first embodiment. It is sectional drawing to which the principal part which shows a comparative example was expanded. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 6 is an enlarged cross-sectional view of a main part of a recording head according to a second embodiment. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head that is an example of a liquid jet head according to Embodiment 1 of the present invention, FIG. 2 is a plan view of the ink jet recording head, and FIG. It is AA 'sectional view taken on the line.

  As shown in the drawing, the ink jet recording head 10 of this embodiment includes an actuator unit 20 and a flow path unit 30 to which the actuator unit 20 is fixed.

  The actuator unit 20 includes a piezoelectric actuator 40, a flow path forming substrate 22 in which the pressure generation chamber 21 is formed, a vibration plate 23 provided on one side of the flow path forming substrate 22, and the flow path forming substrate 22. And a pressure generation chamber bottom plate 24 provided on the direction side.

The flow path forming substrate 22 is made of, for example, a ceramic plate such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ) having a thickness of about 150 μm, or a metal plate such as stainless steel.

  In the present embodiment, the flow path forming substrate 22 is formed with two rows in which a plurality of pressure generating chambers 21 are arranged in parallel along the width direction. A vibration plate 23 made of a thin plate such as zirconia having a thickness of 10 μm is fixed to one surface of the flow path forming substrate 22, and one surface of the pressure generating chamber 21 is sealed by the vibration plate 23. .

  The pressure generation chamber bottom plate 24 is a plate-like member that is fixed to the other surface side of the flow path forming substrate 22 and seals the other surface of the pressure generation chamber 21. Further, the pressure generation chamber bottom plate 24 is provided in the vicinity of one end portion in the longitudinal direction of the pressure generation chamber 21, a supply communication hole 25 that communicates the pressure generation chamber 21 and a manifold described later, and the longitudinal direction of the pressure generation chamber 21. A nozzle communication hole provided in the vicinity of the other end and communicating with a nozzle opening described later.

  The piezoelectric actuator 40 is provided in each of the regions facing the pressure generation chambers 21 on the vibration plate 23. For example, in this embodiment, two rows of the pressure generation chambers 21 are provided. There are also two rows.

  Here, as shown in FIG. 3, each piezoelectric actuator 40 includes a lower electrode film 43 provided on the diaphragm 23, a piezoelectric layer 44 provided independently for each pressure generation chamber 21, The upper electrode film 45 is provided on the piezoelectric layer 44. The piezoelectric layer 44 is formed by attaching or printing a green sheet made of a piezoelectric material. Further, the lower electrode film 43 is provided over the piezoelectric layers 44 arranged side by side and serves as a common electrode for each piezoelectric actuator 40 and functions as a part of the diaphragm. Of course, the lower electrode film 43 may be provided for each piezoelectric layer 44.

  In addition, a terminal portion 46 that conducts to the piezoelectric actuator 40 is provided in a region opposite to the peripheral wall of the pressure generating chamber 21 at one longitudinal end of each piezoelectric actuator 40. The terminal portion 46 is provided for each of the piezoelectric actuators 40 and is electrically connected to the terminal electrode 46 that is electrically connected to the upper electrode film 45 of the piezoelectric actuator 40 and the lower electrode film 43 that is drawn out to both ends of the piezoelectric actuator 40 in the parallel arrangement direction. Terminal portions (not shown) are juxtaposed in the direction in which the piezoelectric actuators 40 are juxtaposed. In the present embodiment, two rows of the terminal portions 46 arranged in parallel between the rows of the piezoelectric actuators 40 arranged in parallel are provided. An external wiring 60 such as a flexible printing circuit (FPC) or a tape carrier package (TCP) is connected to the terminal portion 46, and an external print signal is supplied to the piezoelectric actuator 40 via the external wiring 60. The

  The flow path forming substrate 22, the vibration plate 23, and the pressure generation chamber bottom plate 24, which are each layer of the actuator unit 20, are formed of a clay-like ceramic material, a so-called green sheet, to a predetermined thickness, for example, a pressure generation chamber. After drilling 21 and the like, they are laminated and fired to integrate them without requiring an adhesive. Thereafter, the piezoelectric actuator 40 is formed on the vibration plate 23.

  On the other hand, the flow path unit 30 is a manifold forming substrate on which an ink supply port forming substrate 31 joined to the pressure generating chamber bottom plate 24 of the actuator unit 20 and a manifold 32 serving as a common ink chamber of the plurality of pressure generating chambers 21 are formed. 33 and a nozzle plate 35 in which nozzle openings 34 are formed.

  The ink supply port forming substrate 31 is made of a zirconia thin plate having a thickness of 150 μm, and is provided with a nozzle communication hole 36 for connecting the nozzle opening 34 and the pressure generating chamber 21. The ink supply port forming substrate 31 is provided with an ink supply port 37 for connecting the manifold 32 and the pressure generating chamber 21 together with the supply communication hole 25 described above. Further, the ink supply port forming substrate 31 is provided with an ink introduction port 38 that communicates with each manifold 32 and supplies ink from an external ink tank.

  The manifold forming substrate 33 is formed of a plate material having corrosion resistance, such as 150 μm stainless steel, which is suitable for configuring the ink flow path. Further, the manifold forming substrate 33 receives a supply of ink from an external ink tank (not shown) and supplies the ink to the pressure generating chamber 21 and a nozzle communication that connects the pressure generating chamber 21 and the nozzle opening 34. And a hole 39. That is, the ink from the manifold 32 is supplied to the pressure generation chamber 21 through the supply communication hole 25, and the ink in the pressure generation chamber 21 is changed into the nozzle communication hole 26 and the nozzle communication hole 36 by the pressure fluctuation in the pressure generation chamber 21. Ink droplets are ejected from the nozzle openings 34 through the nozzle communication holes 39.

  The nozzle plate 35 is provided with a nozzle opening 34 penetrating through a plate member made of, for example, a metal such as stainless steel or a ceramic such as silicon. Two or more nozzle openings 34 are provided for one pressure generating chamber 21, and in this embodiment, two nozzle openings 34a and 34b are provided for one pressure generating chamber 21 (see FIG. 4). ).

  A water repellent film 50 is provided on the liquid ejection surface S (the side facing the direction in which the ink droplets are ejected) where the nozzle openings 34 of the nozzle plate 35 are opened. In the present embodiment, the liquid ejecting surface S is the surface of the nozzle plate 35, but since the water repellent film 50 is provided on the surface of the nozzle plate 35, the actual liquid ejecting surface is the water repellent film 50. The surface.

  The water repellent film 50 is not particularly limited as long as it has water repellency with respect to the liquid (ink) to be ejected. For example, a metal film containing a fluorine-based polymer or a molecular film of metal alkoxide having liquid repellency. Etc. can be used.

  Here, the water repellent film 50 made of a metal film containing a fluorine-based polymer can be formed, for example, by performing eutectoid plating directly on the liquid ejection surface S of the nozzle plate 35.

  When a metal alkoxide molecular film is used as the water repellent film 50, for example, by providing a base film made of a plasma polymerized film on the nozzle plate 35 side, the water repellent film 50 made of the molecular film and the nozzle plate 35 Can be improved. The base film made of a plasma polymerized film can be formed, for example, by polymerizing silicone with argon plasma gas. The water-repellent film 50 made of a metal alkoxide molecular film is formed, for example, by mixing a silane coupling agent such as alkoxysilane with a solvent such as thinner to form a metal alkoxide solution. By soaking, a molecular film in which metal alkoxide is polymerized can be formed. Incidentally, when a metal alkoxide molecular film is used as the water repellent film 50, even if a base layer is provided, it is thinner than a liquid repellent film made of a metal film containing a fluoropolymer formed by eutectoid plating. In addition to being able to be formed, there is an advantage that the liquid repellency is not deteriorated even when the liquid ejection surface S is wiped by wiping when cleaning the head surface, and the liquid repellency can be improved. Of course, “rubbing resistance” and “liquid repellency” are inferior, but a liquid repellent film made of a metal film containing a fluorine-based polymer can also be used.

  Here, the nozzle openings 34a and 34b and the water repellent film 50 will be described in more detail with reference to FIG. 4 is an enlarged cross-sectional view of a main part taken along line BB ′ of FIG.

  As shown in FIGS. 2 and 4, two nozzle openings 34 a and 34 b communicating with one pressure generation chamber 21 are arranged in the nozzle plate 35 in parallel with the pressure generation chamber 21. Further, the two nozzle openings 34 a and 34 b communicate with one pressure generation chamber 21 through the nozzle communication hole 26 and the nozzle communication hole 39. Such a distance between the nozzle openings 34 a and the nozzle openings 34 b is arranged at a desired density of the nozzle openings 34. In the present embodiment, the distance between the two nozzle openings 34a and 34b is set at an interval of 600 dpi, that is, 42.4 μm.

  Each of the nozzle openings 34a and 34b is provided on the first nozzle portion 341 provided on the liquid ejecting surface S facing the ink droplet ejection side and on the pressure generating chamber 21 (nozzle communication hole 39) side. Second nozzle part 342 formed.

  In the present embodiment, the first nozzle portion 341 is provided with substantially the same diameter in the thickness direction of the nozzle plate, which is the ink droplet ejection direction.

  The second nozzle part 342 has a shape in which the opening area gradually decreases from the pressure generation chamber 21 (nozzle communication hole 39) side toward the liquid ejection surface S side. In the present embodiment, the opening area of the second nozzle portion 342 gradually decreases toward the liquid ejection surface S by inclining the inner wall surface of the second nozzle portion 342 with respect to the inner wall surface of the first nozzle portion 341. I did it.

  Needless to say, the opening area of the first nozzle portion 341 may be gradually reduced toward the liquid ejection surface S, similarly to the second nozzle portion 342.

  In the nozzle plate 35 provided with such nozzle openings 34a and 34b, the water-repellent film 50 is provided on the liquid ejection surface S side where the first nozzle portion 341 opens as described above.

  The water repellent film 50 is provided continuously over one surface (liquid ejection surface S) from which the liquid of the nozzle plate 35 is discharged. Although not particularly shown, when the cover plate or the like is bonded to the liquid ejection surface S of the nozzle plate 35, if the water repellent film 50 is not provided in the region to be bonded by the adhesive, the bonding strength can be increased. Can be raised.

The water repellent film 50 includes a water repellent part 51 a extending continuously from the liquid ejection surface S of the nozzle plate 35 to the inner surface of the nozzle opening 34 a and a water repellent part 51 b extending to the inner surface of the nozzle opening 34 b. And. In the present embodiment, the water repellent parts 51a and 51b are provided halfway through the depth of the first nozzle part 341 of the nozzle openings 34a and 34b. And the water repellent parts 51a and 51b provided in the nozzle openings 34a and 34b communicating with one pressure generation chamber 21 (individual flow path) are formed at different depths. The “depth” referred to in the present embodiment is a direction from the liquid ejection surface S of the nozzle opening 34 (34a, 34b) toward the pressure generating chamber 21. More specifically, the nozzle opening 34a, water-repellent portion 51a is formed at a depth d ₁ from the liquid ejecting surface S. On the other hand, in the nozzle opening 34b, the water repellent part 51b is formed with d ₂ shallower than d ₁ from the liquid ejection surface S (d ₁ > d ₂ ).

In this way, by changing the depths d ₁ and d ₂ from the liquid ejection surface S where the water repellent portions 51 a and 51 b of the nozzle openings 34 a and 34 b are provided, as shown in FIG. An ink meniscus is formed at the boundary between the region where 51a and 51b are provided and the region where the water repellent film 50 is not provided.

In the ink jet recording head 10, by driving the piezoelectric actuator 40, pressure fluctuation is applied to the ink in the pressure generation chamber 21 to vibrate the meniscus, whereby the ink is separated from the meniscus and ejected as ink droplets. That is, ink droplets are ejected from the two nozzle openings 34a and 34b due to pressure fluctuations in one pressure generating chamber 21 that communicates in common. At this time, the positions of the meniscuses (positions in the liquid ejecting direction) are different in the nozzle openings 34a and 34b, so that the ejection start positions of the ink droplets X ₁ and X ₂ ejected from the two nozzle openings 34a and 34b. The two ink droplets X ₁ and X ₂ ejected from the two nozzle openings 34a and 34b fly without being arranged side by side. Note that the term “lateral” here refers to a direction orthogonal to the flight direction.

Here, as shown in FIG. 5, when the water-repellent portions 51a and 51b are formed at the same depth in the two nozzle openings 134a and 134b, the positions of the ink meniscuses formed in the two nozzle openings 134a and 134b. Are the same. For this reason, the two ink droplets X ₃ and X ₄ ejected from the two nozzle openings 134 a and 134 b bend and fly in directions away from each other. As a cause of the two ink droplets X ₃ and X ₄ being bent and flying in this way, the influence of the airflow is considered. That is, since the flow resistances of the nozzle communication holes 39 immediately before the two nozzle openings 134a and 134b are the same, the flying speeds of the two ink droplets X ₃ and X ₄ are the same, and the two ink droplets X ₃ , X ₄ is flying while adjacent to each other. At this time, since the space between the two ink droplets X ₃ and X ₄ is narrow and the gas does not easily enter, the gas flows easily outside the two ink droplets X ₃ and X ₄ , so that the two ink droplets X ₃ and X ₄ The eddy current is generated only on the outer side of the ink, and the two ink droplets X ₃ and X ₄ are pulled in the direction away from each other by the eddy current, so that the two ink droplets X ₃ and X ₄ are bent and fly away. it is conceivable that. Moreover, the cause of the flight bending of ink droplets X _3, X _4, in addition to the influence of the air flow, for example, the influence of the electrostatic force of the two ink droplets X _3, X ₄ (Coulomb force) and the like are also contemplated. That is, when the two ink droplets X ₃ and X ₄ are charged to the same polarity, they move in directions away from each other. As described above, when the two ink droplets X ₃ and X ₄ ejected from the two nozzle openings 134a and 134b fly away from each other, the landing positions on the recording medium such as paper are shifted. The print quality will deteriorate.

Therefore, in the present embodiment, as shown in FIG. 4, the two nozzle openings 34 a and 34 b have different water repellent portions 51 a and 51 b by different depths (formation regions) from the liquid ejection surface S, thereby reducing the two nozzles. The positions of the meniscuses of ink formed in the openings 34a and 34b (positions in the liquid ejection direction) are made different to determine the flight start positions of the _two ink droplets X ₁ and X ₂ ejected from the two nozzle openings 34a and 34b. change, without two ink droplets X _1, X ₂ are adjacent when flying, on both sides of each of the ink droplets X _1, X ₂ to generate an eddy flow due to the air flow, the bending of ink droplets X _1, X ₂ You can fly straight. Thereby, the landing position of the ink droplet on the recording medium can be made highly accurate, and the printing quality can be improved. In addition, since the two ink droplets X ₁ and X ₂ do not adjoin when flying, the influence of the Coulomb force acting between the _two ink droplets X ₁ and X ₂ can be reduced.

Further, as in the present embodiment, by providing two nozzle openings 34a and 34b for one pressure generating chamber 21, the resolution can be increased and the optical density (OD value; Optical Density) of the printed matter can be increased. Can be high. The optical density (OD value: Optical Density) is the degree of opacity of the translucent medium expressed by log (I ₀ / I) (I ₀ is the intensity of incident light and I is the intensity of reflected light). That is. In this way, the optical density of the dots formed by ejecting ink droplets from the plurality of nozzle openings 34a and 34b is higher. This is considered to be the relationship between the ink weight and the dot diameter. Specifically, the dot diameter of the ink droplet ejected with half the ink weight is larger than half the dot diameter when the ink droplet ejected with the predetermined ink weight adheres to the recording medium. This is because the ink droplets that land on the recording medium have a dome shape (spherical crown shape), but if the ink weight decreases at this time, the height of the dot from the recording medium decreases, so the diameter The (dot diameter) is not halved but larger than half. Therefore, when ink droplets are ejected from two nozzle openings with the same ink weight as when one nozzle opening is provided for the pressure generating chamber, the area (the dot diameter defines the area where the ink droplet covers the recording medium). It is considered that the optical density of the printed material is increased.

  Further, since printing is performed with a smaller ink weight (an ink droplet having a smaller dot diameter) than the ink weight when one nozzle opening is provided for the pressure generating chamber, the penetration of the ink into the recording medium is reduced. . Further, it is considered that by reducing the permeation of the ink into the recording medium, the drying property is improved and the optical density of the printed matter is increased. Therefore, useless consumption of ink can be suppressed.

  A method of manufacturing such water repellent parts 51a and 51b having different depths will be described in detail with reference to FIG. FIG. 6 is a cross-sectional view illustrating a method for manufacturing a recording head according to the first embodiment of the invention.

  First, as shown in FIG. 6A, the other surface (the second nozzle portion 342 side) opposite to the one surface that becomes the liquid ejection surface S of the nozzle plate 35 in which the nozzle openings 34 (34a, 34b) are formed. The photosensitive resin film 200 is press-contacted to the surface. At this time, a part of the photosensitive resin film 200 enters the second nozzle part 342 side of the nozzle openings 34a and 34b while controlling the viscosity by temperature. Further, the amount of the photosensitive resin film 200 that enters the nozzle openings 34a and 34b is different between the nozzle opening 34a and the nozzle opening 34b. Specifically, the pressure for pressing the photosensitive resin film 200 on the nozzle opening 34b side is increased with respect to the pressure for pressing the photosensitive resin film 200 on the nozzle opening 34a side. Thereby, the amount of the photosensitive resin film 200 that enters the nozzle opening 34a decreases, and the amount that enters the nozzle opening 34b increases. That is, the photosensitive resin film 200 enters only to the second nozzle part 342 side of the first nozzle part 341 through the nozzle opening 34a, and enters the liquid ejection surface S side of the first nozzle part 341 through the nozzle opening 34b.

  Next, as shown in FIG. 6B, the photosensitive resin film 200 is irradiated with ultraviolet rays and cured.

  Next, as shown in FIG. 6C, a water repellent film 50 is formed on the surface of the nozzle plate 35. At this time, since the surface opposite to the liquid ejection surface S of the nozzle plate 35 is covered with the photosensitive resin film 200, the water repellent film 50 is not formed on the surface opposite to the liquid ejection surface S of the nozzle plate 35. Further, the water repellent film 50 is also formed on the inner surface of the first nozzle portion 341 of the nozzle opening 34 (34 a, 34 b), but the amount of penetration is regulated by the photosensitive resin film 200. For this reason, the water-repellent portions 51a and 51b of the water-repellent film 50 can be formed at different depths (intrusion amounts) between the nozzle opening 34a and the nozzle opening 34b. The water-repellent film 50 formed here may be formed by eutectoid plating or a molecular film of metal alkoxide.

  Next, as shown in FIG. 6D, by removing the photosensitive resin film 200 from the nozzle plate 35, the nozzle plate 35 in which the water-repellent film 50 is selectively provided only in a desired region is formed. The

  In the present embodiment, since the flow path unit 30 is provided with two rows of the pressure generating chambers 21, the nozzle plate 35 is also formed with two rows of nozzle openings 34 (actually four rows). ing. The nozzle plate 35 is bonded to the opposite surface of the flow path forming substrate 22 of the manifold forming substrate 33 to seal one surface of the manifold 32.

  Such a flow path unit 30 is formed by fixing the ink supply port forming substrate 31, the manifold forming substrate 33, and the nozzle plate 35 with an adhesive, a heat welding film, or the like. In the present embodiment, the manifold forming substrate 33 and the nozzle plate 35 are formed of stainless steel. However, for example, the manifold forming substrate 33 and the nozzle plate 35 are formed of ceramics, and the flow path unit 30 is integrally formed in the same manner as the actuator unit 20. You can also

  And such a flow-path unit 30 and the actuator unit 20 are joined and fixed through the adhesive agent and the heat welding film.

  In the ink jet recording head 10 having such a configuration, ink is taken into the manifold 32 from the ink cartridge (storage unit) via the ink introduction port 38, and the ink is passed through the liquid flow path from the manifold 32 to the nozzle opening 34. Then, a recording signal from a drive circuit (not shown) is supplied to the piezoelectric actuator 40, whereby a voltage is applied to each piezoelectric actuator 40 corresponding to each pressure generating chamber 21 to bend the diaphragm 23 together with the piezoelectric actuator 40. By deforming, the pressure in each pressure generating chamber 21 is increased, and ink droplets are ejected from each nozzle opening 34 (two nozzle openings 34a and 34b).

(Embodiment 2)
FIG. 7 is an enlarged cross-sectional view of a main part of an ink jet recording head showing an example of a liquid jet head according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As illustrated in FIG. 7, the nozzle plate 35 </ b> A is provided with two nozzle openings 34 c and 34 d corresponding to one pressure generation chamber 21.

  One nozzle opening 34c includes a first nozzle portion 341 provided on the liquid ejection surface S side and a second nozzle portion 342A provided on the pressure generation chamber 21 side.

  The other nozzle opening 34d includes a first nozzle portion 341 provided on the liquid ejection surface S side and a second nozzle portion 342B provided on the pressure generation chamber 21 side.

  In the present embodiment, the first nozzle portion 341 is provided with substantially the same diameter in the thickness direction of the nozzle plate, which is the ink droplet ejection direction.

  The second nozzle portions 342A and 342B have a shape in which the opening area gradually decreases from the pressure generation chamber 21 (nozzle communication hole 39) side toward the liquid ejection surface S side. In the present embodiment, the opening area of the second nozzle portion 342 gradually increases toward the liquid ejection surface S by inclining the inner wall surfaces of the second nozzle portions 342A and 342B with respect to the inner wall surface of the first nozzle portion 341. I tried to make it small.

And these two 2nd nozzle part 342A, 342B is formed so that the angle (theta) ₁ and angle (theta) ₂ with respect to the 1st nozzle part 341 may become a different angle.

Specifically, in the nozzle opening 34c in which the water repellent part 51a is provided deep from the liquid ejection surface S, the taper angle θ ₁ (angle with respect to the first nozzle part 341) of the second nozzle part 342A is the angle θ of the nozzle opening 34d. It is provided at a larger angle than ₂ . That is, in the nozzle opening 34d in which the water repellent part 51a is provided shallow from the liquid ejection surface S, the taper angle θ ₂ (angle with respect to the first nozzle part 341) of the second nozzle part 342B is compared with the angle θ ₁ of the nozzle opening 34c. Provided at a small angle (θ ₁ > θ ₂ ).

For example, as shown in FIG. 7B, when the photosensitive resin film 200 is pressed against the surface opposite to the liquid ejection surface S of the nozzle plate 35, as in the first embodiment described above. Even if the photosensitive resin film 200 is pressed into contact with the nozzle openings 34c and 34d with the same pressure, the volume of the photosensitive resin film 200 enters because the volumes of the second nozzle portions 342A and 342B of the nozzle openings 34c and 34d are different. Can be different. That is, the second nozzle portion 342A of the nozzle opening 34c is an angle theta ₁ is greater with respect to the first nozzle portion 341, since the volume of the second nozzle portion 342A is large, the photosensitive resin film 200 enters the first nozzle portion 341 The amount is reduced. In contrast, the second nozzle portion 342B of the nozzle openings 34d, the angle theta ₂ is small with respect to the first nozzle portion 341, it volume of the second nozzle portion 342B is smaller than that of the second nozzle portion 342A of the nozzle openings 34a Therefore, the amount of the photosensitive resin film 200 entering the first nozzle portion 341 increases.

  For this reason, even if the pressure which presses the photosensitive resin film 200 in the nozzle openings 34c and 34d is the same, the area | region of the 1st nozzle part 341 of the nozzle openings 34c and 34d covered with the photosensitive resin film 200 can be changed. . Thereafter, by irradiating the photosensitive resin film 200 with ultraviolet rays and forming the water-repellent film 50 on the surface of the nozzle plate 35A, the water-repellent portions 51a and 51b having different depths can be easily formed.

  In the present embodiment, since the inner diameter D of the first nozzle portion 341 of the nozzle openings 34c and 34d is the same, the size (weight) of the ink droplets ejected from the two nozzle openings 34c and 34d is substantially the same. Become. Therefore, it is possible to form the water repellent portions 51a and 51b having different depths while suppressing the deterioration of the print quality. The effect of the water repellent parts 51a and 51b having different depths is the same as that of the first embodiment.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above.

  For example, in the first and second embodiments described above, the two nozzle openings 34 a, 34 b and 34 c, 34 d communicating with the one pressure generation chamber 21 are provided. Three or more nozzle openings may be provided. Even in this case, if the depth of the water repellent portion of each nozzle opening from the liquid ejection surface S is different, the height at which ink droplets are started to be ejected from each nozzle opening (height until landing) is different. And the flight trajectory can be straightened.

  Further, in the above-described first and second embodiments, the pressure generating means using the thick film type piezoelectric actuator 40 is exemplified, but the present invention is not particularly limited thereto. For example, the lower electrode, the piezoelectric layer, and the upper electrode are formed. Further, a thin film type piezoelectric actuator that is sequentially laminated by a lithography method, a longitudinal vibration type piezoelectric actuator that alternately laminates piezoelectric materials and electrode forming materials and expands and contracts in the axial direction, and the like can be used. In addition, as a pressure generating means, a heating element is arranged in the pressure generating chamber, and bubbles are generated from the nozzle opening by bubbles generated by the heat generated by the heating element, or static electricity is generated between the diaphragm and the electrode. Thus, a so-called electrostatic actuator that discharges liquid droplets from the nozzle openings by deforming the diaphragm by electrostatic force can be used.

  Further, the ink jet recording head 10 of each of these embodiments constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 8 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus I shown in FIG. 8, ink jet recording head units 1A and 1B (hereinafter also referred to as head units 1A and 1B) each having a plurality of ink jet recording heads 10 include a cartridge 2A and an ink supply unit. 2B is detachably provided, and the carriage 3 on which the head unit 1A is mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be freely movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the head units 1A and 1B are mounted is moved along the carriage shaft 5. . On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet P, which is a recording medium such as paper fed by a not-shown paper feed roller, is wound around the platen 8. It is designed to be transported.

  In the ink jet recording apparatus I described above, the ink jet recording head 10 (head units 1A, 1B) is mounted on the carriage 3 and moves in the main scanning direction. However, the present invention is not particularly limited thereto. The present invention can also be applied to a so-called line recording apparatus in which the ink jet recording head 10 is fixed and printing is performed simply by moving a recording sheet P such as paper in the sub-scanning direction.

  Furthermore, the present invention is intended for a wide range of liquid jet heads in general, for example, for manufacturing recording heads such as various ink jet recording heads used in image recording apparatuses such as printers, and color filters such as liquid crystal displays. The present invention can also be applied to a coloring material ejecting head, an organic EL display, an electrode material ejecting head used for forming electrodes such as an FED (field emission display), a bioorganic matter ejecting head used for biochip manufacturing, and the like. Further, although the ink jet recording apparatus I has been described as an example of the liquid ejecting apparatus, the liquid ejecting apparatus using the other liquid ejecting heads described above can also be used.

  I ink jet recording apparatus (liquid ejecting apparatus), S liquid ejecting surface, 10 ink jet recording head (liquid ejecting head), 20 actuator unit, 21 pressure generating chamber, 22 flow path forming substrate, 23 diaphragm, 24 pressure generating chamber Bottom plate, 30 flow path unit, 31 ink supply port forming substrate, 32 manifold, 33 manifold forming substrate, 34, 34a to 34d nozzle opening, 35, 35A nozzle plate, 26, 39 nozzle communication hole, 40 piezoelectric actuator (pressure generating means) ), 43 lower electrode film, 44 piezoelectric layer, 45 upper electrode film, 46 terminal part, 50 water repellent film, 51a, 51b water repellent part, 200 photosensitive resin film

Claims (4)

A pressure generating chamber;
Pressure generating means for causing a pressure change in the liquid in the pressure generating chamber;
A nozzle plate formed with a nozzle opening communicating with the pressure generating chamber;
A liquid ejecting head comprising a water-repellent film provided on the liquid ejecting surface side of the nozzle plate,
A plurality of nozzle openings are provided for one pressure generation chamber,
The liquid ejecting head according to claim 1, wherein the water repellent film is provided to different depths from the liquid ejecting surface on the inner surfaces of the plurality of nozzle openings with respect to one pressure generating chamber.   The liquid ejecting head according to claim 1, wherein the water repellent film is formed by eutectoid plating.   The liquid ejecting head according to claim 1, wherein the water-repellent film includes a metal alkoxide molecular film.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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