JP2008188882A - Inkjet head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an inkjet head which forms a uniform protective film on surfaces of an ink chamber and a common ink chamber, and also to provide an inkjet head which allows ink to be rapidly filled with the ink chamber and the common ink. <P>SOLUTION: An inkjet head 50 is provided with: a base member 1; a plurality of channel walls 5a formed spaced from the upper surface of the base member 1; drive electrodes 6 which are formed on the side surfaces of the channel walls 5a and drive the channel walls 5a: protective films formed on the surfaces of the drive electrodes 6; a cover member 60 bonded on the upper surfaces of the channel walls 5a; a plurality of ink chambers 5 provided between the channel walls 5a, respectively; a common ink chamber 12 which is formed in the cover member 60 and communicates with the plurality of ink chambers 5; and a low repellent part which is provided in the inner surface of the cover member 60 defining the common ink chamber 12, extends over the plurality of ink chambers 5, and has a lower repellency than the protective films. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inkjet head and an inkjet head manufacturing method, and more particularly to an inkjet head used in a printer or the like and an inkjet head manufacturing method.

  In recent years, in printers, non-impact printing apparatuses such as an ink jet system that can easily cope with colorization and multi-gradation are rapidly spreading instead of impact printing apparatuses. As an ink jet head as an ink discharge apparatus used for this, a drop-on-demand type that discharges only ink droplets necessary for printing is particularly noted because of its good discharge efficiency and ease of cost reduction. Yes. As the drop-on-demand type, a Kaiser method or a thermal jet method is mainly used.

  However, the Kaiser method has a drawback that it is difficult to reduce the size and is not suitable for high density. In addition, although the thermal jet method is suitable for increasing the density, the ink is heated with a heater to generate bubbles in the ink and discharged using the energy of the bubbles. Heat resistance of the ink is required, and it is difficult to extend the life of the heater, and there is a problem that power consumption increases due to poor energy efficiency.

  In order to solve such drawbacks of each method, an ink jet method using shear mode deformation of a piezoelectric material has been proposed. This method uses an electrode formed on both sides of an ink channel wall made of piezoelectric material (hereinafter referred to as “channel wall”) to generate an electric field in a direction perpendicular to the polarization direction of the piezoelectric material. The channel wall is deformed in the share mode, and ink droplets are ejected by utilizing the pressure wave fluctuation generated at that time, which is suitable for increasing the density of the nozzles, reducing the power consumption, and increasing the driving frequency.

  Recently, it is widely used for industrial applications such as discharging conductive materials with an inkjet head using this shear mode deformation, drawing wiring, and discharging R, G, B ink to produce color filters. Is beginning to be done.

  When used for such industrial purposes, it is essential to increase the ink jet head size in order to increase the number of ejection channels and improve the throughput.

  Another difference from consumer printers is that it requires a specified amount of droplets to land at a specified address, and it is strictly required to control landing accuracy and droplet volume. When using an inkjet head, it becomes a big problem.

  For example, as shown in FIGS. 18 and 19, an inkjet head 50 using the shear mode deformation described in Japanese Patent Laid-Open No. 2006-82342 includes a base member 1 in which a plurality of ink chambers 5 are formed, ink supply A cover member 23 in which a common ink chamber 12 serving as a path is formed, an anisotropic conductive film (hereinafter referred to as “ACF”) 10, a flexible printed circuit board 11 in which external electrodes are formed, and a nozzle hole 17 are opened. Nozzle plate 16 is provided.

  The ink flow path is formed by bonding the base member 1 and the cover member 23 together.

  On the side surface of the channel wall 5a, a drive electrode 6 for generating an electric field therein is formed over the entire height direction of the channel wall 5a. The base member 1 made of a piezoelectric material is subjected to a polarization process so that the polarization directions are opposite at the approximate center of the channel wall 5a as shown by 1A and 1B in FIG. Hereinafter, the end where the nozzle plate 16 is joined is referred to as a front end 27, and the opposite side is referred to as a rear end 28. In the inkjet head, the side on which the cover member 23 is disposed is defined as the upper side, and the side on which the base member 1 is disposed is defined as the lower side.

  An organic protective film (not shown) is formed on the entire interior of the inkjet head 50 including the drive electrode 6 for the purpose of insulating and protecting the drive electrode 6 from ink. The organic protective film is preferably polyparaxylylene which can obtain a uniform film thickness distribution in the ink chamber 5.

FIG. 19 is a side view seen from the arrow C in FIG. (The nozzle plate is omitted.)
The pressure required for ink ejection is generated mainly in the region A where the upper surface of the channel wall 5a is bonded and fixed to the cover member 23 in the region where the drive electrode 6 is formed on the side surface of the channel wall 5a. As described above, the area A 1 where the channel wall 5a that mainly generates pressure necessary for ink ejection is joined to the cover member 23 is referred to as an “active area”. Although the shear mode deformation also occurs in the region B, the ink channel in the region B communicates with the common ink chamber 12 which is a relatively large space, and the pressure is dispersed toward the common ink chamber 12 even when the pressure is applied. The For this reason, the region B is a portion that does not contribute much to ink ejection. The ink supplied from the outside to the common ink chamber 12 is stored in the common ink chamber 12 and supplied to the ink chamber 5 as needed. The ink that has flowed into the ink chamber 5 is ejected from the nozzle hole 17 by the shear mode deformation. Is done.

  With the increase in the head size of such an ink jet head, the following problems occur.

  When the channel wall 5a of the ink jet head is driven, a pressure wave is generated in the active area A. The pressure wave plays a role of ejecting ink from the nozzle hole 17 and at the same time follows the ink chamber 5 from the active area A. It also propagates in the direction of the end portion 28. Most of the propagated pressure wave is reflected by the water hammer effect at the interface between the space sandwiched between the channel walls 5a and the common ink chamber 12, and returns to the active region A again without being attenuated. For this reason, it may interfere with the pressure wave for the subsequent ink discharge and may adversely affect the ink discharge. In particular, when the drive frequency is increased, the subsequent ink is discharged before the remaining pressure wave is attenuated, so that the discharge speed of the subsequent ink may fluctuate greatly, or in some cases the ink discharge stops. There was a case. Therefore, it is necessary to wait for the next ejection until the residual vibration is settled, and it is necessary to reduce the driving frequency to suppress the printing speed.

  Therefore, regarding the problem that residual vibration adversely affects ink ejection, Japanese Patent Application Laid-Open No. 2004-136634 proposes the following method as a method for suppressing residual vibration.

The structure of the inkjet head 50 proposed in Japanese Patent Application Laid-Open No. 2004-136634 will be described with reference to FIGS. FIG. 20 is a side view of an ink jet head 50 based on the conventional technology. The head structure shown in FIG. 18 includes the base member 1, the cover member 23, the drive electrode 6, the organic protective film (not shown), the nozzle plate, and the structure of the inkjet head described in Japanese Patent Laid-Open No. 2006-82342. 16 is included. A gap 80 is provided at a certain depth between adjacent ink chambers at the rear end of the active region. This region is called region C with respect to active region A. When the pressure wave passes through this region and travels toward the common ink chamber, it passes through the gap 80, and proceeds to the common ink chamber while being absorbed and attenuated by the large viscous resistance of the ink. Therefore, the residual vibration of the pressure wave can be suppressed by the gap.
JP 2006-82342 A JP 2004-136634 A

  The ink jet head described in Japanese Patent Application Laid-Open No. 2004-136634 has a common ink chamber formed so as to penetrate the ink chamber in a direction substantially orthogonal to the ink chamber, and a gap for suppressing residual vibration of the pressure wave. Has a part. In such an ink jet head, in order to form the electrode protective film in order to insulate the drive electrode from the ink, a gas for forming the organic protective film is supplied from the ink supply port and the ink discharge port.

  In this case, an organic protective film having a desired film thickness can be formed in the ink chamber portion close to the ink supply port and the ink discharge port. On the other hand, the desired ink chamber portion in the central portion of the inkjet head can be formed. This causes a problem that the film thickness is not reached.

  Such a problem becomes more conspicuous as the inkjet head width, that is, the number of channels increases. In some cases, the drive electrode cannot be insulated from the ink in the ink chamber portion at the center of the inkjet head.

  On the other hand, if an organic protective film is formed so that the ink chamber portion in the central portion of the inkjet head has a desired film thickness, the ink chamber portion close to the ink supply port and the ink discharge port has a desired film thickness or more. As a result, a problem arises in that the flow path resistance of the ink chamber increases or the ink chamber opening narrows, making it difficult to bond the nozzle.

  Furthermore, since an organic protective film with high liquid repellency is formed on substantially the entire surface of the ink chamber and the inner surface of the common ink chamber, the ink can be supplied to the ink chamber or the common ink chamber. However, it is difficult to spread in the ink chamber and the common sink chamber, and there is a problem that it takes time to fill the ink.

  The present invention has been made in view of the above problems, and a first object thereof is to provide an ink jet head manufacturing method in which a protective film is uniformly formed on the surfaces of an ink chamber and a common ink chamber. is there. A second object is to provide an ink jet head that can fill ink chambers and common ink chambers within a short time.

  The inkjet head according to the present invention includes a base member, a plurality of channel walls formed on the upper surface of the base member with a space therebetween, and a drive electrode formed on a side surface of the channel wall and capable of driving the channel wall. The inkjet head includes a protective film formed on the surface of the drive electrode, a cover member bonded to the upper surface of the channel wall, a plurality of ink chambers provided between the channel walls, And a common ink chamber that communicates with the plurality of ink chambers. Further, the inkjet head includes a low liquid repellency portion that is provided on the inner surface of the cover member that defines the common ink chamber, extends over the plurality of ink chambers, and has lower liquid repellency than the protective film.

  Preferably, the cover member includes an ink supply unit capable of supplying ink into the common ink chamber and an ink discharge unit capable of discharging ink in the common ink chamber.

  Preferably, the cover member includes a gap portion formed on a surface facing the upper surface of the channel wall, and spaced apart from the upper surface of the channel wall to form a gap between the upper surface of the channel wall and the cover member.

  Preferably, the low liquid repellency portion is made of glass, and the protective film is made of poly-para-xylylene and derivatives thereof. Preferably, the thickness of the protective film is 3 to 15 μm.

  A method of manufacturing an inkjet head unit according to the present invention includes a step of forming a plurality of channel walls at an interval on the upper surface of the base member, a step of forming a metal film on the surface of the base member so as to cover the channel walls, Removing a metal film located on an upper surface of the channel wall, and forming a drive electrode capable of driving the channel wall on a side surface of the channel wall. Further, the method for manufacturing the ink jet head portion includes a cover member having an opening extending in the arrangement direction of the channel walls so as to communicate with the plurality of ink chambers provided between the channel walls. Forming a protective film on the surface of the drive electrode by supplying a film material from the opening.

  Preferably, the method further includes a step of defining the common ink chamber by closing the opening with a closing member having a lower liquid repellency than the protective film.

  Preferably, the step of forming the cover member includes a step of attaching a plate-like member extending in the arrangement direction of the channel walls to the upper surface of the channel wall, and a step of forming an opening in the plate-like member.

  Preferably, the step of forming the opening includes a step of forming the opening so as to extend from the ink chamber located at one end in the arrangement direction of the channel walls to the ink chamber located at the other end in the arrangement direction.

  According to the inkjet head of the present invention, ink can be filled in the ink chamber and the common ink chamber in a short time. According to the method for manufacturing an ink jet head according to the present invention, a protective film having a substantially uniform desired film thickness can be formed on the inner wall surface of each ink chamber and the common ink chamber.

  The inkjet head and the manufacturing method thereof according to the present embodiment will be described with reference to FIGS. In addition, the same code | symbol may be attached | subjected to the structure which is the same or it corresponds, and the description may be abbreviate | omitted.

  FIG. 1 is a perspective view of an inkjet head 50 according to the present embodiment, and is an exploded perspective view of each component. FIG. 2 is a side sectional view of the inkjet head 50. In the example shown in FIG. 1, the inkjet head 50 includes a base member 1 and a cover member 60 provided on the upper surface of the base member 1.

  The base member 1 is made of a piezoelectric material, and is formed by bonding PZT (lead zirconate titanate) substrates 1A and 1B. The base member 1 is polarized in the thickness direction, and has a thickness of about 0.9 mm, for example.

  On the upper surface of the base member 1, there are formed a plurality of channel walls 5a arranged at intervals, and a plurality of ink chambers 5 positioned between the channel walls 5a.

  On one end side of the ink chamber 5, an ejection port 5 b through which ink is ejected outward from the ink chamber 5 is located. A nozzle plate 16 in which nozzle holes 17 corresponding to the respective discharge ports 5b are formed is provided in front of the discharge ports 5b.

  As shown in FIG. 2, the inner surface of the base member 1 that defines the bottom surface of the ink chamber 5 is located upward so as to approach the upper surface of the channel wall 5a as it extends from the ejection port 5b in the extending direction of the ink chamber 5. Displace. And the electrode extraction part 9 is formed in the edge part side located on the opposite side to the discharge outlet 5b. The electrode lead portion 9 extends from the end portion of the base member 1 located on the opposite side to the discharge port 5b, for example, over a range of 2 mm. The upper surface of the electrode lead portion 9 is, for example, about 10 μm lower than the upper surface of the adjacent channel wall 5a.

  A flexible printed board 11 is electrically connected to the electrode lead-out portion 9 with the ACF 10 interposed therebetween.

  The cover member 60 is formed so as to cover a portion of the base member 1 that is located slightly on the discharge port 5b side from the electrode outlet 9b from the discharge port 5b of the base member 1. A common ink chamber 12 communicating with each ink chamber 5 is defined on the inner surface of the cover member 60. Ink is supplied to the common ink chamber 12 and can be supplied to each ink chamber 5.

  The cover member 60 includes a discharge port side wall portion 2 bonded (adhered) to the upper surface of the discharge port 5b and the channel wall 5a located in the vicinity thereof, and the extending direction of the ink chamber 5 with respect to the discharge port side wall portion 2. And a lid member 4 provided across the upper surface of the drawer side wall portion 3 and the upper surface of the discharge port side wall portion 2.

  The cover member 60 has an ink supply port (ink supply unit) 13 for supplying ink into the common ink chamber 12 and an ink discharge port (ink) for discharging the ink filled in the common ink chamber 12 to the outside. The discharge part) 14 is formed.

  FIG. 3 is a cross-sectional view of the inkjet head 50 in the vicinity of the ejection portion 5b. As shown in FIG. 3, the channel wall 5a is deformed (driven) on both side surfaces of the channel wall 5a defining each ink chamber 5 and the inner surface of the base member 1 defining the bottom surface of the ink chamber 5. ) Is formed. The drive electrode 6 is not formed on the upper surface of each channel wall 5 a and is not short-circuited between the ink chambers 5.

  The drive electrode 6 is formed across two opposing side surfaces of the two channel walls 5 a that define one ink chamber 5 and the inner surface of the base member 1 that defines the bottom surface of the ink chamber 5.

  Here, the polarization process is performed so that the polarization directions are opposite to each other at the approximate center in the height direction of the channel wall 5a. When a voltage is applied to the drive electrode 6, the channel wall 5a is sandwiched between the drive electrodes 6. Area can be voluntarily deformed in share mode.

  Then, between the drive electrode 6 formed on the inner surface of the two ink chambers 5 adjacent to the selected ink chamber 5 and the drive electrode 6 formed on the inner surface of the selected ink chamber 5. By applying different voltages, the channel wall 5a is deformed so that the volume of the selected ink chamber 5 is reduced. As a result, the ink filled in the selected ink chamber 5 is ejected to the outside from the ejection port 5 b and the nozzle hole 17. The direction of deformation depends on the direction of the electric field inside the channel wall 5a and the direction of polarization of the piezoelectric material.

  When the ink chamber 5 is filled with ink, the channel walls 5a defining the selected ink chamber 5 are deformed so as to be separated from each other so that the volume of the ink chamber 5 is increased.

  The drive electrode 6 is formed on the inner wall surface of the ink chamber 5 by vapor deposition, sputtering, plating, or the like, and aluminum, copper, or the like is applicable.

  An organic protective film (protective film) 7 is formed on the upper surface of the drive electrode 6. As a result, even if the ink chamber 5 is filled with ink, direct contact between the ink and the drive electrode 6 can be suppressed, and corrosion of the drive electrode can be suppressed. Furthermore, insulation between the ink and the drive electrode 6 can be ensured. As the organic protective film 7, for example, polyparaxylylene and its derivatives are preferable from the viewpoint of good coverage around the ink jet head 50.

  The organic protective film 7 is also formed on the inner surface of the discharge port side wall 2 and the inner surface of the drawer side wall 3 that define the common ink chamber 12 shown in FIG. On the other hand, the organic protective film 7 is not formed on the surface of the cover member 4 of the cover member 60.

  The lid member 4 is made of a material having a lower liquid repellency than the organic protective film 7, for example, glass, and the surface thereof is exposed in the common ink chamber 12.

  That is, the wettability of the surface of the lid member 4 located in the common ink chamber 12 is better than the wettability of the surface of the organic protective film 7, and the lid member is more than the contact angle of the organic protective film 7 with water relative to the ink. The contact angle of the surface of 4 is small. For example, the contact angle of the organic protective film 7 is about 60 degrees, and the contact angle of the surface of the lid member 4 with water is about 10 degrees. For this reason, the ink tends to spread on the surface of the lid member 4 rather than the surface of the organic protective film 7.

  Furthermore, by using the lid member 4 as a glass substrate, the thermal expansion coefficients of the lid member 4 and the discharge outlet side wall 2 and the extraction side wall 3 can be matched or approximated. The thickness of the lid member 4 is, for example, about 0.5 mm.

  In the present embodiment, the lid member 4 is separate from the discharge outlet side wall 2 and the drawer side wall 3 but is not limited thereto. For example, as the cover member 60 in which the lid member 4, the discharge outlet side wall portion 2 and the extraction portion side wall portion 3 are integrated, the inner surface of the cover member 60 defining the common ink chamber 12 is wettable by the organic protective film 7. Alternatively, a low liquid repellency portion having a liquid repellency lower than that of the organic protective film 7 may be formed intermittently or continuously in the arrangement direction of the ink chambers 5.

  FIG. 4 is a schematic diagram schematically showing the state of ink when ink supply is started from the ink supply port 13.

  As shown in FIG. 4, the ink supplied from the ink supply port 13 first starts to flow on the surface of the lid member 4. This is because ink tends to spread on the surface of the lid member 4 than on the surface of the organic protective film 7.

  As shown in FIGS. 5 and 6, when the supplied ink reaches the ink discharge port 14 side, the ink chamber 5 located on the ink supply port 13 side is filled with ink. Further, when ink is supplied, as shown in FIG. 7, each ink chamber 5 is filled with ink, and the common ink chamber 12 is filled with ink, thereby completing the ink supply.

  In this way, by extending the region in which the ink easily spreads in the common ink chamber 12 in the arrangement direction of the ink chambers 5, the ink can easily enter the common ink chamber 12, and the ink can be supplied for a short time. Can be completed with.

  Here, if the ink supply speed is slow in the process of filling each ink chamber 5 with ink, the ink chamber 5 on the side close to the ink supply port 13 is filled with ink, and then the ink chamber 5 is adjacent to the ink chamber 5. Ink moves. On the other hand, if the ink supply speed is high, the ink is supplied to the adjacent ink chamber 5 over the channel wall 2a before the ink chamber 5 on the side near the ink supply port 13 is filled with ink. There is a case. For this reason, the ink chamber 5 may not be completely filled with ink. Air enters the ink chamber 5 that is not filled with ink. At this time, in the process of supplying ink, the inside of the ink chamber 5 is in a state where a positive pressure is applied, and the air does not float on the common ink chamber 12 but stays in the ink chamber 5.

  Thus, the air that has entered the ink chamber 5 floats in the common ink chamber 12 after the completion of ink filling. Then, by discharging a certain amount of ink from the ink discharge port 14, it is possible to discharge the bubbles mixed in the common ink chamber 12 together with the ink and perform a recovery operation from the non-discharge state to the discharge state.

  Since such a recovery motion can be performed, it is possible to suppress frequent occurrence of undischarge channels immediately after ink filling.

  In FIG. 1 and FIG. 2, the channel wall 5a defining the ink chamber 5 selected as described above is deformed in a state where the ink is supplied into each ink chamber 5 as described above, so that the ink is ejected from the nozzles. The ink is discharged from the hole 17 toward the object, and printing is performed.

  Here, on the lower surface of the discharge port side wall portion 2, there are a close contact portion 2 a in close contact with the discharge port 5 b and the upper surface of the channel wall 5 a extending from the discharge port 5 b in the extending direction of the ink chamber 5, and the close contact portion 2 a. On the other hand, a gap 8 is formed which is recessed away from the upper surface of the channel wall 5a to form a gap with the upper surface of the channel wall 5a.

  Here, the volume of the ink chamber 5 in the ink chamber 5 located below the close contact portion 2a of the ejection port side wall portion 2 is changed, so that the volume in the ink chamber 5 fluctuates and the ink filled in the ink chamber 5 is discharged. It discharges outside from the discharge outlet 5b.

  Here, when the two channel walls 2a defining the selected ink chamber 5 are deformed so as to reduce the volume in the ink chamber 5, the pressure in the ink chamber 5 rises. The pressure fluctuation is transmitted as a pressure wave from the ejection port 5b side toward the common ink chamber 12 side.

  Then, in the process in which this pressure wave travels from the ejection port 5b side to the common ink chamber 12 side, the pressure wave reaches the gap formed between the gap 8 and the upper surface of the channel wall 5a. At this time, the pressure wave advances to the common ink chamber 12 while being absorbed and attenuated by the large viscous resistance of the ink when passing through the gap formed between the gap portion 8 and the upper surface of the channel wall 5a. . As a result, it is possible to suppress the pressure wave from being reflected on the inner surface of the common ink chamber 12 and entering the ink chamber 5 again, and the reflected pressure wave has entered the ink chamber 5 again. However, it can be in a greatly attenuated state.

  For this reason, when the reflected pressure wave enters the ink chamber 5 again, the channel wall 5a is newly driven and is reflected on the inner surface of the common ink chamber 12 even if ink is discharged outside. It can be prevented that ink is not ejected or the ejection amount becomes insufficient due to interference with the pressure wave.

  By suppressing the residual vibration in this way, the pressure wave reflected by the inner wall surface of the cover member 60 defining the common ink chamber 12 and the pressure wave newly generated by driving the channel wall 5a interfere with each other. This can be suppressed, and the ejection characteristics at high frequency of each channel can be stabilized. As a result, high-speed and high-quality printing faithful to the print data is possible.

  A method of manufacturing the ink jet head configured as described above will be described. FIG. 8 is a perspective view showing a first step of the manufacturing process of the base member 1. In the example shown in FIG. 8, first, a base member 1w is formed from a plate-like member 1C made of a piezoelectric member and a plate-like member 1D arranged on the upper surface of the plate-like member 1C.

  Then, the dicing blade 30 is advanced in one direction with the upper surface of the base member 1w being moved in the vertical direction at a predetermined position, so that the channel wall 5a and the electrode lead-out portion 9 are formed on the upper surface of the base member 1w. And a plurality of each.

  Specifically, a plurality of channel walls 5a are formed at equal intervals, and the ink chambers 5 are defined between the channel walls 5a. Further, a plurality of electrode lead portions 9 are formed at intervals between the channel walls 5a.

  Thereafter, a metal film such as aluminum or copper is formed on the upper surface of the base member 1w on which the channel wall 5a and the electrode lead portion 9 are formed by vapor deposition, sputtering, plating, or the like.

  As a result, a metal film is formed on the surface of the base member 1 w that covers the surface of the channel wall 5 a and defines the bottom surface of the ink chamber 5, and a metal film is also formed on the surface of the electrode lead-out portion 9.

  FIG. 9 is a perspective view showing a second step of the manufacturing process of the base member. In the example shown in FIG. 9, the metal film located on the upper surface of the channel wall 5a and the metal film formed on the upper surface of the base member 1w adjacent to the channel wall 5a and the ink chamber 5 are removed.

  As a result, the metal film remains on the surface of the base member 1w that defines both side surfaces of the channel wall 5a and the bottom surface of the ink chamber 5, and the drive electrode 6 is formed. Further, the metal film remains on the upper surface of the electrode lead portion 9.

  Here, the metal film formed on the upper surface of the electrode lead-out portion 9 and the drive electrode 6 are integrated, and a voltage is applied to the electrode lead-out portion 9 so that a predetermined voltage is applied to the drive electrode 6. It is possible.

  FIG. 10 is a perspective view schematically showing a process of manufacturing the cover member 60. In the example shown in FIG. 10, a groove 12A extending from one end to the other end is formed on the surface of the plate-like member 60A, and the groove 12A is adjacent to the groove 12A. A gap portion 8 having a shallower depth is formed.

  Since the plate-like member 60A is bonded to the base member 1, the thermal expansion coefficient of the plate-like member 60A, the cover member 60, and the thermal expansion coefficient preferably match. For this reason, the plate-like member 60 </ b> A is composed of a piezoelectric member similar to the base member 1.

  In the step of forming the groove portion 12A, a groove forming a part of the common ink chamber 12 is performed on the plate-like member with a dimming blade having a width of 1 mm. The depth of the groove processing was about half the thickness of the plate member, and the groove width was 2 mm.

  The thickness of the plate member 60A is preferably determined by the width of the inkjet head 50, that is, the number of channels and the groove width of the common ink chamber 12. In the present invention, the number of channels is 300 ch, the groove width is 2 mm, and the cover member is The thickness was 2 mm.

  Next, shallow groove processing of the gap 8 is performed with the same dicing blade. The gap portion 8 is formed so as to communicate with a groove constituting a part of the common ink chamber 12, and the machining is a chopper process for moving the dicing blade 30 up and down, and the gap portion 8 is opened at the end of the plate-like member 60 </ b> A. Process so as not to.

  In the example shown in FIG. 10, one gap portion 8 and one groove portion 12A are formed, but a plurality of these gap portions 8 and groove portions 12A are formed at intervals.

  FIG. 11 is a perspective view schematically showing a step of bonding the plate-like member 60A and the base member 1w.

  In FIG. 11, the plate-like member 60 </ b> A is formed with a plurality of grooves 12 </ b> A at intervals, and a plurality of gaps 8 (not shown) are also formed.

  A plurality of channel walls 5a, ink chambers 5, electrode lead-out portions 9 and drive electrodes 6 are also formed on the surface of the base member 1w.

  Then, an adhesive is applied to a portion of the upper surface of the plate-like member 60A shown in FIG. 10 adjacent to the gap portion 8 and the groove portion 12A, and an epoxy-based adhesive is also applied to the upper surface of the base member 1w shown in FIG. The agent is applied to bond the plate-like member 60A and the base member 1w.

  Thus, the base member 1w which the inkjet head chip | tip which is a some inkjet head unit connected can be obtained by adhere | attaching the base member 1w and the plate-shaped member 60A. Then, the base member 1w and the plate member 60A are divided for each inkjet head chip.

  FIG. 12 is a perspective view showing a process after the plate-like member 60A and the base member 1w are bonded and divided for each inkjet head chip. In the process shown in FIG. 12, a groove portion 12A is formed on the inner surface on the upper surface of the base member 1 on which the plurality of channel walls 5a, the ink chamber 5, the electrode lead portion 9, and the drive electrode 6 are formed. A cover member 60B is provided.

  The cover member 60B includes a top surface portion 4A, a wall portion 2A continuously provided on one side of the top surface portion 4A, and a wall portion 3A facing the wall portion 2A in the extending direction of the ink chamber 5. Yes. The wall portion 2A is connected to the side portion of the top surface portion 4A located on the discharge port 5b side, and the wall portion 3A is connected to the side portion on the electrode lead-out portion 9 side. Then, the dicing blade 30 is used to form an opening in the top surface portion 4A.

  FIG. 13 is a cross-sectional view when the opening 150A is formed in the top surface portion 4A of the cover member 60B. As shown in FIG. 13, by forming the opening 150 </ b> A, the discharge port side wall portion 2 and the extraction portion side wall portion 3 are formed, and between the discharge port side wall portion 2 and the extraction portion side wall portion 3. The upper surface of the positioned base member 1 is exposed outward.

  In the example shown in FIG. 13, the opening 150A extends from one end of the top surface 4A shown in FIG. 12 toward the arrangement direction of the ink chambers 5 and reaches the other end. ing. The opening 150 </ b> A extends in the arrangement direction of the ink chambers 5. The top surface portion 4A is formed so as to extend from one end portion in the arrangement direction of the ink chambers 5 and reach the other end portion.

  In the example shown in FIGS. 12 and 13, the top surface portion 4 </ b> A is formed so as to reach the other end portion from one end portion, but is not limited thereto.

  For example, as shown in FIG. 12, the opening 150A includes a region 150A1 located above the ink chamber 5 located in the central portion of the top surface portion 4A in the arrangement direction of the ink chambers 5, and the top surface portion 4A. It may be an opening that does not reach both ends. Furthermore, it is not limited to forming the opening 150A in the top surface portion 4A, and the opening 150 may be formed in the wall 3A shown in FIG.

  In the present embodiment, the cover member is divided to form the discharge port side wall portion 2, the extraction portion side wall portion 3, and the opening 150A. However, the discharge port side wall portion 2 and the extraction portion side wall portion are formed. 3 may be arranged separately from each other on the upper surface of the channel wall 5a.

  FIG. 14 is a cross-sectional view showing a process of connecting the flexible printed circuit board 11 to the electrode lead-out portion 9 after forming the individualized inkjet head 50A. As shown in FIG. 14, an electrode lead-out portion 9 is formed in a range of about 2 mm from the rear end portion 28 of the base member 1, and the upper surface of the electrode lead-out portion 9 is the upper surface of the channel wall 5a. To a certain depth of about 10 μm. And the flexible printed circuit board 11 is connected with respect to the electrode extraction part 9 which has a depth of about 10 micrometers.

  The flexible printed circuit board 11 is formed by forming a metal wiring on a flexible film such as polyimide, and the electrode part 11 a of the flexible printed circuit board 11 connected to the electrode lead-out part 9 is thinner than the width of the ink chamber 5. It has a thickness of 10 μm or more.

  By pressing and heating the electrode lead-out part 9 of the inkjet head and the electrode part of the flexible printed circuit board 11 through the ACF 10, only the pressurized part of the ACF 10 can be conducted. Thereby, the metal film formed on the surface of the electrode extraction part 9 and the electrode part 11a of the flexible printed circuit board 11 can be electrically connected. Then, electrical connection is performed so that each drive electrode 6 located on the inner surface of each ink chamber 5 has the same potential. Accordingly, it is possible to drive the ink jet head by applying a voltage to the drive electrode 6 from the outside. In this example, CP9742KS (manufactured by Sony Chemical Co., Ltd.) was used as the ACF, and pressure bonding was performed under the conditions of 120 N, 150 ° C., and 70 sec.

  FIG. 15 is a cross-sectional view showing a step of forming an organic protective film after connecting the flexible printed board 11 to the electrode lead-out portion 9. Before the organic protective film is formed, the wiring portion of the flexible printed board 11 is masked with a masking tape or the like to prevent adhesion. The width of the upper surface of each channel wall 5a (the width in the arrangement direction of the channel walls 5a) is about 30 mm to 150 mm.

  As the organic protective film 7 to be formed, polyparaxylylene and its derivatives are preferable from the viewpoint of chemical resistance and good fit around the ink jet head 50. In this example, polymonochloroparaxylylene (Chemical Formula 4) was formed using dichlorodiparaxylylene as a dimer as a material. The organic material (coating material) is not limited to this, and the effects of the present invention can be obtained by using various derivatives of dimer. For example, polyparaxylylene (Chemical Formula 3) using diparaxylylene (Chemical Formula 1), which is a dimer, and a polyparaxylylene film using another derivative (Chemical Formula 5) as a type of polyparaxylylene film. Examples include xylylene and others shown in (Chemical 6 and 7).

  A method for forming the organic protective film will be described with reference to FIG. The film forming apparatus will be described with reference to FIG. A vaporization chamber 40 having a vaporization heater 39, a pyrolysis furnace 42 having a pyrolysis heater 41, a film forming chamber 43 having a sample holder (not shown), and liquid nitrogen 44 for trapping unreacted monomer gas. A film forming apparatus including a cold trap 45 cooled in step 1 and a rotary pump 46 for evacuation is used. First, a dimer is installed in the vaporization chamber 40, and then the rotary pump 46 is operated to exhaust the vacuum to 20 mTorr or less, and at the same time, the pyrolysis heater 41 of the pyrolysis furnace 42 is energized to raise the temperature to about 700 ° C. Prepare for film formation. Next, liquid nitrogen 44 is introduced into the cold trap 45 in order to trap the monomer gas that has not contributed to the film formation without exhausting it during the film formation and to improve the background vacuum. Next, the vaporization heater is energized to change the temperature of the vaporization chamber 40 in a stepwise manner from 110 ° C. to 160 ° C. to vaporize the vaporization chamber 40. At this time, the dimer gas diffused and flowed to the pyrolysis furnace 42 is pyrolyzed and thermally excited to generate a monomer gas (Chemical Formula 2), and further diffused to the film forming chamber 43 to adhere the inkjet head main body. The organic protective film 7 is formed by colliding with the body surface and causing adsorption and polymerization reactions. In this example, polymonochloroparaxylylene was formed to a thickness of 7 μm with respect to the surface of the front end portion 27. As shown in FIG. 15, the structure of the inkjet head 50 when forming the organic protective film 7 includes an opening 150 </ b> A formed between the outlet side wall 2 and the extraction side wall 3. The organic protective film is formed with the upper surface of the base member 1 positioned between the outlet side wall 2 and the lead-out side wall 3 exposed to the outside. By uniformly supplying the gas for forming the organic protective film 7 to each ink chamber 5 through the opening 150A, the uniform organic protective film 7 having no film thickness distribution can be formed. Here, the opening 150 </ b> A is opened so as to include a region located above the ink chamber 5 located at the center portion in the arrangement direction of the ink chambers 5. For this reason, variation in the distance between the opening 150A and each ink chamber 5 is suppressed, and it is formed on the inner surface of the channel wall 5a that defines each ink chamber 5 and on the surface of the drive electrode 6. Variations in the thickness of the organic protective film 7 can be suppressed.

  Further, the film thickness of the organic protective film 7 formed on the surface of the gap 8 can also be suppressed from varying depending on the position, and the pressure wave attenuation characteristics can be suppressed from varying depending on the position. .

  Furthermore, the opening 150A extends in the arrangement direction of the ink chambers 5 and extends from the ink chamber 5 located at the end of the ink chamber 5 in the arrangement direction to the ink chamber 5 located at the other end. For example, as shown in FIG. 17, the distance between all the ink chambers 5 and the openings 150 </ b> A does not vary, and the organic protection formed on the surfaces of the ink chambers 5 and the gaps 8. The film thickness of the film 7 can be made uniform.

  Specifically, the thickness range of the organic protective film 7 can be 3 to 15 μm. By forming the organic protective film 7 in such a range, waste in material cost and film formation time can be achieved while satisfying the minimum organic protective film thickness required for chemical resistance and insulation on the central side of the inkjet head. With the configuration of the organic protective film thus prevented, it is possible to obtain an ink jet head in which a difference in the ejection characteristics at high frequencies of each channel is prevented.

  As shown in FIG. 2, after forming the organic protective film 7, a cover member 150 </ b> A is provided to straddle the upper surface of the discharge port side wall portion 2 and the upper surface of the extraction portion side wall portion 3. Is specified. This also defines an ink supply port 13 that can supply ink to the common ink chamber 12 and an ink discharge port 14 that can discharge ink in the common ink chamber 12.

  Although the embodiment of the present invention has been described above, it should be considered that the embodiment disclosed this time is illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. Furthermore, the above numerical values are examples, and are not limited to the above numerical values and ranges.

  The present invention can be used in an inkjet head and an inkjet head manufacturing method, and is particularly suitable for an inkjet head used in a printer or the like and an inkjet head manufacturing method.

It is a perspective view of the ink jet head concerning this embodiment. It is a sectional side view of an inkjet head. It is sectional drawing of the inkjet head in the discharge part vicinity. FIG. 4 is a schematic diagram schematically showing the state of ink when ink supply is started from an ink supply port. FIG. 5 is a schematic diagram illustrating an ink state when a little time has elapsed from the state illustrated in FIG. 4. FIG. FIG. 6 is a schematic diagram illustrating an ink state when a little time has elapsed from the state illustrated in FIG. 5. It is a model which shows the state of the ink when time passes slightly from the state shown by FIG. It is a perspective view which shows the 1st process of the manufacturing process of a base member. It is a perspective view which shows the 2nd process of the manufacturing process of a base member. It is a perspective view which shows typically the process of manufacturing a cover member. It is a perspective view which shows typically the process of bonding a plate-shaped member and a base member. It is a perspective view which shows the process after making a plate-shaped member and a base member adhere | attach and dividing | segmenting for every inkjet head chip. It is sectional drawing when an opening part is formed in the top | upper surface part of a cover member. It is sectional drawing which shows the process of connecting a flexible printed circuit board to an electrode extraction part, after forming the individualized inkjet head. It is sectional drawing which shows the process of forming an organic protective film, after connecting a flexible printed circuit board to an electrode extraction part. It is a schematic diagram explaining the film-forming method of an organic protective film. It is sectional drawing of the inkjet head in a gap | interval part. It is a perspective view explaining 1st prior art. It is a side view explaining 1st prior art. It is a side view explaining the 2nd prior art. It is a perspective view explaining the 2nd prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base member, 2a Channel wall, 2 Side wall part of discharge port, 3 Side wall part of drawer | drawing-out part, 4 Cover member, 5 Ink chamber, 5a Channel wall, 5b Outlet, 6 Drive electrode, 7 Organic protective film, 8 Gap part, 9 Electrode extraction part, 11 Flexible printed circuit board, 11a Electrode part, 12 Common ink chamber, 13 Ink supply port, 14 Ink discharge port, 16 Nozzle plate,
17 nozzle hole, 23 cover member, 60 cover member.

Claims (9)

A base member;
A plurality of channel walls formed at intervals on the upper surface of the base member;
A drive electrode formed on a side surface of the channel wall and capable of driving the channel wall;
A protective film formed on the surface of the drive electrode;
A cover member joined to the upper surface of the channel wall;
A plurality of ink chambers respectively provided between the channel walls;
A common ink chamber formed in the cover member and communicating with the plurality of ink chambers;
A low liquid repellency portion provided on an inner surface of the cover member defining the common ink chamber, extending over the plurality of ink chambers and having a lower liquid repellency than the protective film;
An ink jet head comprising:   The inkjet head according to claim 1, wherein the cover member includes an ink supply unit capable of supplying ink into the common ink chamber and an ink discharge unit capable of discharging ink in the common ink chamber.   The said cover member is formed in the surface facing the upper surface of the said channel wall, and is spaced apart from the upper surface of the said channel wall, The gap | interval part which forms a clearance gap between the upper surface of the said channel wall and the said cover member is included. The inkjet head according to claim 1 or 2.   The inkjet according to any one of claims 1 to 3, wherein the low liquid repellency portion is made of glass, and the protective film is made of poly-para-xylylene and a derivative thereof. head.   The inkjet head according to claim 1, wherein the protective film has a thickness of 3 to 15 μm. Forming a plurality of channel walls on the upper surface of the base member at intervals;
Forming a metal film on the surface of the base member so as to cover the channel wall;
Removing the metal film located on the upper surface of the channel wall, and forming a drive electrode capable of driving the channel wall on a side surface of the channel wall;
Forming a cover member having an opening extending in the arrangement direction of the channel walls on the upper surface of the channel walls so as to communicate with a plurality of ink chambers respectively provided between the channel walls;
Supplying a coating material from the opening to form a protective film on the surface of the drive electrode;
A method for manufacturing an inkjet head, comprising:   The inkjet head manufacturing method according to claim 6, further comprising a step of closing the opening with a closing member having a lower liquid repellency than the protective film to define the common ink chamber. The step of forming the cover member includes attaching a plate-like member extending in the arrangement direction of the channel walls to the upper surface of the channel wall;
The method for manufacturing an ink jet head according to claim 6, further comprising a step of forming the opening in the plate-like member.   The step of forming the opening includes a step of forming the opening so as to extend from an ink chamber located at one end in the arrangement direction of the channel walls to an ink chamber located at the other end in the arrangement direction. Item 9. A method for manufacturing an inkjet head according to Item 8.

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