JP2006026927A - Liquid ejection head, its nozzle plate, and method of manufacturing the nozzle plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head which can prevent flight deflection of liquid droplets such as ink droplets while reducing manufacturing costs by simplifying manufacturing processes, and to provide its nozzle plate and a method of manufacturing the nozzle plate. <P>SOLUTION: A rear face 21 of a nozzle plate substrate 14 is coated with the use of a masking material 22. After the masking material 22 is coated, a liquid repellent coating layer is formed at a front face 20 of the nozzle plate substrate 14. Nozzle openings 11 are formed in the nozzle plate substrate 14 by carrying out punching working of thrusting a punch 23 from the front face 20 with the liquid-repellent coating layer 19 formed thereat. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid ejecting head of a liquid ejecting apparatus represented by an ink jet printer, a nozzle plate thereof, and a method of manufacturing the nozzle plate.

  The liquid ejecting head of the liquid ejecting apparatus includes, for example, an ink jet recording head used in an image recording apparatus such as a printer, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, and an organic EL (Electro Luminescence) display. There are electrode material ejecting heads used for forming electrodes such as FED (surface emitting display), bioorganic matter ejecting heads used for manufacturing biochips (biochemical elements), and the like.

  In this type of liquid ejecting head, a pressure chamber and a nozzle opening are communicated with each other, and a pressure generating element such as a piezoelectric vibrator is driven to cause a pressure fluctuation in the liquid in the pressure chamber, thereby causing an ink droplet or the like from the nozzle opening. The liquid droplets are ejected.

In such a liquid ejecting head, depending on a state around the nozzle opening, that is, a wet state of a liquid such as ink around the nozzle opening, a flying bend may occur in the ejected liquid droplets. In other words, when the periphery of the nozzle opening is wet with a liquid such as ink, the droplet at the time of ejection is pulled by the surface tension of this portion, and as a result, flight bending occurs.
In order to prevent such flight bending, it is common to apply a liquid repellency treatment on the surface of the nozzle plate to eliminate the adhesion of droplets such as ink around the nozzle opening when the nozzle plate is manufactured. .

  However, as shown in FIG. 5A, when the liquid repellent coating layer 31 is formed on the surface 32 of the nozzle plate substrate 30, it is very difficult to perform the liquid repellent treatment only on the surface 32 of the nozzle plate substrate 30. Therefore, a part of the liquid repellent coating layer 31 may wrap around into the nozzle openings 34 non-uniformly. For example, the wraparound of the liquid repellent coating layer 31 may be deep in a part (right side in FIG. 5A) or shallow in another part (left side in FIG. 5A). If the liquid repellent coating layer 31 wraps around the nozzle openings 34 in a non-uniform manner, the wet state of the liquid such as ink on the inner peripheral surface of the nozzle openings 34 becomes non-uniform, and the flight of the ejected droplets is bent. Still occurs.

With respect to such a problem, the invention proposed in Patent Document 1 is such that the photosensitive resin material 35 as a masking material is pressed from the surface 32 of the nozzle plate substrate 30 as shown in FIG. The nozzle opening 34 is covered with the photosensitive resin material 35 from the back surface 33 of the nozzle plate substrate 30, and the nozzle opening 34 is plugged with the photosensitive resin material 35. This is a nozzle plate surface treatment method in which the liquid-repellent coating layer 31 is prevented from wrapping into the opening 34.
Japanese Patent Laid-Open No. 6-246921

  However, in the manufacturing method described above, at least two surfaces of the front surface 32 and the rear surface 33 of the nozzle plate substrate 30 must be coated with the photosensitive resin material 35, respectively. Since the amount also increases, there arises a problem that not only the production efficiency is lowered but also the manufacturing cost is raised. Then, an uncovered portion 36 that is not slightly covered with the liquid-repellent coating layer 31 is generated around the nozzle opening 34 after the stopper of the photosensitive resin material 35 is removed, so that liquid such as ink around the nozzle opening 34 is formed. Therefore, there is a problem that it is not possible to reliably prevent the flight bending of droplets such as ink droplets.

  The present invention has been made in view of such problems, and the object of the present invention is to simplify the manufacturing process and reduce the manufacturing cost, while preventing the flight bending of the droplets such as ink droplets. An object of the present invention is to provide a liquid ejecting head, a nozzle plate thereof, and a method for manufacturing the nozzle plate.

The present invention has been proposed in order to achieve the above object, and the masking material is used to coat the back surface of the nozzle plate substrate,
After coating the masking material, a liquid-repellent film layer is formed on the surface of the nozzle plate substrate,
According to another aspect of the invention, there is provided a method for manufacturing a nozzle plate of a liquid jet head, wherein a nozzle opening is formed in the nozzle plate substrate by performing punching in which a punch is pushed from the surface on which the liquid repellent coating layer is formed.
In addition, the back surface of the nozzle plate substrate means a surface on the side bonded to the flow path unit in which the pressure chamber or the like is formed.

  According to the above manufacturing method, by forming the nozzle opening after forming the liquid repellent coating layer on the surface, the liquid repellent coating layer wraps around the nozzle opening and the liquid repellent coating is not coated around the nozzle opening. Since it is possible to prevent the occurrence of non-covered parts, wetting of liquid such as ink on the inner peripheral surface of the nozzle opening becomes uniform, and ink around the nozzle opening that affects the ejection of droplets such as ink droplets, etc. The liquid is no longer wetted. In addition, since it is sufficient to cover the back surface of the nozzle plate substrate before forming the nozzle openings, it is not necessary to mask the nozzle openings. Therefore, it is possible to easily manufacture a nozzle plate of a liquid ejecting head that is unlikely to cause flying bending of droplets such as ink droplets at low cost.

  In the above manufacturing method, after the punching, the back surface of the nozzle plate substrate is polished to remove the bulge portion pushed by the punch on the back surface, and the nozzle opening penetrating the thickness direction of the nozzle plate substrate It is desirable to form.

  Thus, if the said bulging part is removed after punching, the penetrating nozzle opening can be formed in a highly accurate and stable shape. Moreover, the load to the punch at the time of punching can also be suppressed. Therefore, problems such as buckling of the punch can be prevented, and the life of the punch can be improved.

  In the manufacturing method of the above configuration, after the punching, the nozzle plate substrate is polished on the back surface, and the masking material coated on the back surface and the bulging portion pushed out by the punch are removed together, thereby the nozzle You may form the nozzle opening which penetrated the thickness direction of the plate substrate.

  If both the masking material and the bulging part are removed by polishing the back surface of the nozzle plate substrate, there is no need to remove the masking material separately, so the work process can be reduced and the manufacturing cost can be further reduced. Become.

  In these configurations, when the thickness of the nozzle plate substrate is T and the diameter of the nozzle opening formed in the nozzle plate substrate is φN, the punching process is performed under the condition of T ≦ φN × 3. It is desirable to form nozzle openings.

  When punching is performed under the above conditions, the shape of the nozzle opening can be further stabilized, and the punch life can be further improved by preventing the punch from being bent or buckled as much as possible. .

  The nozzle plate of the liquid jet head according to the present invention is manufactured with any one of the above-described configurations, and the liquid jet head includes the nozzle plate. Therefore, the flying bending of droplets such as ink droplets does not occur, manufacturing is easy, and it can contribute to cost reduction.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In the following description, an ink jet recording head (hereinafter referred to as a recording head), which is one form of a liquid ejecting head, will be described as an example.
1A is a cross-sectional view of a recording head, FIG. 1B is a plan view of a nozzle plate with a portion omitted, and FIGS. 2A to 2C are nozzle plate manufacturing steps according to the first embodiment. FIG. 3A is a sectional view of the nozzle pilot hole after punching of the first embodiment, FIG. 3B is a sectional view of the completed nozzle opening, and FIG. FIG. 4B is a cross-sectional view of a nozzle pilot hole after punching according to the second embodiment.

  The recording head 1 shown in FIG. 1 is joined to a synthetic resin head case 2, a vibrator unit 3 stored in a storage space 8 in the head case 2, and a tip (bottom surface) of the head case 2. The flow path unit 4 is generally configured.

  The vibrator unit 3 includes a plurality of piezoelectric vibrators 5 formed in a comb shape, a fixed plate 6 to which a fixed end of each piezoelectric vibrator 5 is joined, and each piezoelectric vibrator 5 and a drive circuit (see FIG. (Not shown) and the like. The distal end surface of the free end portion of the piezoelectric vibrator 5 faces the opening on the flow channel unit 4 side in the housing empty portion 8 and is joined to the island portion 10 formed in the upper portion of the pressure chamber 9 of the flow channel unit 4. The

  The flow path unit 4 includes a nozzle plate 13 provided with a plurality of nozzle openings 11, a flow path substrate 15 in which a plurality of pressure chambers 9 communicating with the nozzle openings 11 are arranged, and one pressure chamber 9. And a diaphragm 16 that divides the portion. The flow path unit 4 has a configuration in which the nozzle plate 13 is bonded to one surface of the flow path substrate 15 and the diaphragm 16 is bonded to the other surface.

  The flow path substrate 15 is made of, for example, a silicon wafer, and is etched so as to store a plurality of pressure chambers 9, a reservoir 17 that stores ink introduced into each pressure chamber 9, and each pressure chamber 9 and reservoir 17. And an ink supply port 18 communicating with each other.

  The nozzle plate 13 is made of a thin stainless plate, for example. For example, as shown in FIG. 1B, a plurality of nozzle openings 11 are arranged in the nozzle plate 13 at a pitch corresponding to the dot density. A method for manufacturing the nozzle plate 13 will be described later.

  The diaphragm 16 has a double structure in which an elastic film such as a PPS film is laminated on a stainless steel support plate, and the support plate corresponding to each pressure chamber 9 is etched into an annular shape. An island portion 10 is formed, and this portion functions as a diaphragm portion. In addition, the portion corresponding to the reservoir 17 is a compliance portion made only of an elastic film by removing the support plate by etching.

  Therefore, in the recording head 1 configured as described above, when a drive signal is input from the drive circuit (not shown) to the piezoelectric vibrator 5 via the conduction line 7, the free end of the piezoelectric vibrator 5 becomes the element longitudinal length. Stretch in the direction. Due to the expansion and contraction of the free end, the island 10 is pushed toward the pressure chamber 9 or pulled in the opposite direction, and the volume of the pressure chamber 9 varies. Since the pressure of the ink stored in the pressure chamber 9 fluctuates due to the volume fluctuation, the ink droplet can be ejected from the nozzle opening 11 by controlling the pressure of the ink.

  Next, a first embodiment of the method for manufacturing the nozzle plate 13 will be described. In this embodiment, after forming the liquid repellent coating layer 19 on the surface 20 of the nozzle plate substrate 14, punching is performed in the thickness direction of the nozzle plate substrate 14 from the liquid repellent coating layer 19 side, that is, the surface 20 side. Thus, the nozzle opening 11 is formed.

  First, as shown in FIG. 2A, a masking material 22 is coated on the back surface 21 of the nozzle plate substrate 14 other than the front surface 20, that is, the liquid repellent film is not applied (masking process). As the masking material 22, for example, a photosensitive resin film that is cured by irradiation with light is used. And this photosensitive resin film is stuck to the part (back surface 21) to mask, and the attached photosensitive resin film is hardened as a masking film by irradiating this part with an ultraviolet-ray.

  Next, as shown in FIG. 2B, a liquid repellent coating layer 19 is uniformly formed on the surface 20 of the nozzle plate substrate 14 (liquid repellent coating forming step). For example, eutectoid plating is used for the liquid repellent coating. In this eutectoid plating coating method, an electrolyte solution containing metal ions such as nickel ions and particles of a liquid repellent polymer resin such as polytetrafluoroethylene is electrolyzed, and this electrolyte solution is stirred into this solution. The nozzle plate substrate 14 connected to the electrodes is immersed, and the plating is uniformly attached to the surface 20. Next, a heat treatment is performed at a temperature not lower than the melting point of polytetrafluoroethylene, for example, 350 ° C. or higher, while applying a load to the nozzle plate substrate 14 to suppress warping, thereby forming a eutectoid plating layer.

  Then, after the liquid repellent coating layer 19 is formed on the front surface 20, the masking material 22 coated on the back surface 21 is dissolved and removed using a solvent (masking material removing step).

When the masking material 22 is removed, as shown in FIG. 2 (c), for example, a punch that pushes in a cylindrical round punch 23 from the front surface 20 side on which the liquid repellent coating layer 19 is formed toward the back surface 21 side. Processing is performed (punch process). At this time, when the tip of the punch 23 is pushed to a depth exceeding the thickness of the nozzle plate substrate 14, a nozzle pilot hole 24 shaped like the punch 23 is formed in the nozzle plate substrate 14 as shown in FIG. It is formed. A portion of the back surface 21 corresponding to the nozzle lower hole 24 becomes a bulging portion 25 pushed out by the punch 23.
In the punching process in the present embodiment, the nozzle pilot hole 24 that does not completely penetrate the nozzle plate substrate 14 is formed. However, the present invention is not limited to this, and the nozzle opening 11 may be penetrated by this punching process. .

Then, the bulging portion 25 on the back surface 21 of the nozzle plate substrate 14 is removed by polishing (bulging portion removing step). When this bulging portion removing step is performed, the bulging portion 25 is removed and the nozzle openings 11 penetrating in the thickness direction of the nozzle plate substrate 14 are formed as shown in FIG.
As described above, when the nozzle opening 11 is formed by removing the bulging portion 25 after the nozzle lower hole 24 is formed by punching, the nozzle opening 11 can be made into a highly accurate and stable shape. Moreover, the load to the punch 23 at the time of punching can be suppressed. Therefore, problems such as buckling of the punch 23 can be prevented and the life of the punch 23 can be improved.

Thus, in this embodiment, the masking material 22 is coated on the back surface 21 of the nozzle plate substrate 14 before the nozzle openings 11 are formed, and the liquid repellent coating layer 19 is formed on the surface 20 of the nozzle plate substrate 14. Since the nozzle opening 11 is formed by punching from the front surface 20 side to the back surface 21 where the liquid repellent coating layer 19 is formed, the liquid repellent coating layer 19 does not wrap around the nozzle opening 11. In addition, the non-covered portion of the liquid repellent coating layer 19 is not generated around the nozzle opening 11. Accordingly, wetting of the ink on the inner peripheral surface of the nozzle opening 11 becomes uniform, and the wetting of the ink around the nozzle opening 11 which affects the ejection of ink droplets is also eliminated. Therefore, it is possible to make it difficult for the ink droplets to be bent.
Further, in order to prevent the liquid repellent coating layer 19 from entering the nozzle opening 11, it is not necessary to cover the nozzle opening 11 with the masking material 22. That is, the masking material 22 only needs to be covered on the flat back surface 21 of the nozzle plate substrate 14 before the nozzle openings 11 are formed, so that the process and cost of masking the nozzle openings 11 can be reduced.
Therefore, according to the manufacturing method of the nozzle plate 13 of the present embodiment, there is an effect that it is possible to easily manufacture the nozzle plate 13 which can suppress the flight bending of the ink droplets and suppress the manufacturing cost. .

  Next, a second embodiment of the method for manufacturing the nozzle plate 13 will be described. The present embodiment is characterized in that the masking material removal step in the first embodiment is not performed, and the masking material 22 covered on the back surface 21 of the nozzle plate substrate 14 is removed together with the bulging portion 25 in the bulging portion removing step. To do.

In this embodiment, after forming the liquid repellent coating layer 19 on the surface 20 of the nozzle plate substrate 14, the masking material removing step is not performed, and the process proceeds to punching as shown in FIG. At this time, when the tip of the punch 23 is pushed to a depth exceeding the thickness of the nozzle plate substrate 14, as shown in FIG. 4B, the nozzle plate hole 14 having a shape following the punch 23 is formed in the nozzle plate substrate 14. A bulging portion 25 is formed on the back surface 21 side and is pushed out by the punch 23.
Also in this embodiment, the nozzle pilot hole 24 may be penetrated by this punching process.

  Then, the bulging portion 25 on the back surface 21 and the masking material 22 are removed by polishing together (bulging portion removing step). As a result, the nozzle openings 11 penetrating in the thickness direction of the nozzle plate substrate 14 are formed.

  According to the present embodiment, since the liquid repellent coating layer 19 is formed on the surface 20 of the nozzle plate substrate 14, punching is performed, and the bulging portion 25 formed by this punching is removed together with the masking material 22. In addition to the same effects as those of the first embodiment, it is not necessary to separately perform a masking material removal step, and the manufacturing cost can be further reduced.

  Here, in each of the above embodiments, when the thickness of the nozzle plate substrate 14 is T and the diameter of the nozzle opening 11 formed in the nozzle plate substrate 14 is φN, the punching conditions of the manufacturing method are as follows: It is desirable to set T ≦ φN × 3. The reason is that it has been obtained from the results of production experiments, and it has been found that if punching is performed under these conditions, there is no risk of failure due to bending or buckling of the punch 23. . For example, the thickness T of a general nozzle plate substrate 14 is 80 μm and the diameter N of the nozzle opening 11 is 40 μm. If these are applied to the above conditional expression, 80 μm ≦ 120 μm, and the above conditional expression is established. Further, punching can be performed without causing the punch 23 to be bent or buckled.

  In the recording head 1 including the nozzle plate 13 manufactured as described above, it is difficult to cause flying bending of droplets such as ink droplets, and as a result, an image such as a rough feeling or white stripes (banding) in the recorded image. Deterioration can be reduced.

  By the way, the present invention can be applied to liquid ejecting heads other than the ink jet recording head as long as the liquid ejecting head includes a nozzle plate. For example, the present invention can be applied to a color material ejecting head used for manufacturing liquid crystal displays, an organic EL display, an electrode material ejecting head used for forming electrodes such as FED, and a bioorganic matter ejecting head used for manufacturing biochips. it can.

(A) is sectional drawing of a recording head, (b) is a front view of the nozzle plate which abbreviate | omitted one part. (A) to (c) is a cross-sectional view showing the manufacturing process of the nozzle plate in the first embodiment. (A) is sectional drawing of the nozzle pilot hole after punching in 1st Embodiment, (b) is sectional drawing of the completed nozzle opening. (A) is the figure which showed the punch process in 2nd Embodiment, (b) is sectional drawing of the nozzle pilot hole after the punch process of 2nd Embodiment. (A) is sectional drawing of the nozzle opening at the time of the conventional nozzle plate manufacture, (b) is sectional drawing of the nozzle opening after formation of the liquid-repellent coating layer in patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head, 2 Head case, 3 Vibrator unit, 4 Flow path unit, 5 Piezoelectric vibrator, 6 Fixed plate, 7 Conduction line, 8 Storage empty part, 9 Pressure chamber, 10 Island part, 11 Nozzle opening, 12 Nozzle Communication port, 13 nozzle plate, 14 nozzle plate substrate, 15 flow path substrate, 16 diaphragm, 17 reservoir, 18 ink supply port, 19 liquid repellent coating layer, 20 surface of nozzle plate substrate, 21 back surface of nozzle plate substrate, 22 Masking material, 23 punches, 24 nozzle hole, 25 bulge

Claims (6)

Cover the back of the nozzle plate substrate with a masking material,
After coating the masking material, a liquid-repellent film layer is formed on the surface of the nozzle plate substrate,
A method of manufacturing a nozzle plate for a liquid jet head, comprising: forming a nozzle opening in the nozzle plate substrate by punching a punch from a surface on which the liquid repellent coating layer is formed.   After the punching process, the back surface of the nozzle plate substrate is polished to remove the bulging portion pushed out by the punch on the back surface, thereby forming a nozzle opening penetrating the thickness direction of the nozzle plate substrate. The method of manufacturing a nozzle plate for a liquid jet head according to claim 1, After the punching, the back surface of the nozzle plate substrate is polished,
The nozzle opening penetrating the thickness direction of the nozzle plate substrate is formed by removing both the masking material coated on the back surface and the bulging portion pushed out by the punch. A nozzle plate manufacturing method for a liquid jet head according to claim 1.   When the thickness of the nozzle plate substrate is T and the diameter of the nozzle opening formed in the nozzle plate substrate is φN, the nozzle opening is formed by punching under the condition of T ≦ φN × 3. The method for manufacturing a nozzle plate for a liquid jet head according to any one of claims 1 to 3.   A nozzle plate of a liquid jet head manufactured by the manufacturing method according to claim 1. A liquid ejecting head comprising the nozzle plate according to claim 5.

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