JP4034053B2 - Inkjet head, electrode connection structure thereof, and method of manufacturing inkjet head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet head, its electrode connection structure, and an inkjet head manufacturing method.
[0002]
[Prior art]
In electrical connection with an external circuit including an IC for driving the inkjet head, an electrode formed in the ink chamber extends outside the ink chamber to form an external extraction electrode (external connection electrode), and the external circuit The electrical connection is made.
[0003]
For example, as shown in FIGS. 14 to 16, a conventional inkjet head has an ink chamber electrode 201 of an actuator 200, an ink chamber electrode (external extraction electrode) 202 extended to a flat portion of the actuator 200, and a bonding wire 205. And a TAB lead (Tape Automated Bonding Reed) 206, a flexible substrate 207, and the like, and electrically connected to the driving IC 40.
[0004]
For example, as shown in FIG. 14, when electrical connection is made with the bonding wire 205, the ink chamber electrode 201 is extended to a flat portion, and an Al wedge wire bonding technique or an Au wedge wire bonding technique is used. A wire is pressed by a bonding capillary in the direction perpendicular to the electrode surface, and solid phase diffusion bonding of metal is performed by applying heated ultrasonic waves.
[0005]
Further, as shown in FIG. 15, in the case of bonding with the outer lead 206 of the TAB lead, the ink chamber electrode 201 is extended to a flat portion, and the outer lead of the TAB device is parallel to the extended flat electrode on the actuator 200. The solder is pre-plated on the surface of the outer lead 206 and soldered by using a lead pressing tool having a heating and pressing mechanism from the direction perpendicular to the flat electrode surface. Further, electrical connection may be performed through ACF (anisotropic conductive film) or ACP (anisotropic conductive paste) instead of solder bonding.
[0006]
Further, as shown in FIG. 16, even when the flexible substrate 207 is connected, solder bonding or bonding by ACF or ACP is performed in the same manner as the bonding of the TAB lead 206.
[0007]
Next, a method for extending these ink chamber electrodes 201 to the flat portion will be described with reference to FIG. First, a dry film resist is laminated on one surface of the piezoelectric element 260 polarized in the thickness direction and cured. Next, the ink chamber 226 is formed by half-dicing the piezoelectric element 260 using a dicing blade of a dicer, the dicing blade is raised to form the rounded portion R at the rear end of the ink chamber, and then the flat portion is dry. Cut only the film resist.
[0008]
In this way, after forming a plurality of ink chambers (ink chamber arrays) 226..., A metal serving as an electrode material such as Al or Cu is obliquely deposited from a direction perpendicular to the longitudinal direction of the ink chamber 226. By performing this operation from the left and right directions (see arrows in FIG. 14) with respect to the longitudinal direction of the ink chamber 226, a metal electrode (ink chamber electrode) 201 is formed on the surface of the ink chamber partition wall, and the dry film resist and Due to the shadowing effect of each ink chamber partition, the metal film forming the metal electrode 210 is formed to about ½ in the thickness direction of the ink chamber.
[0009]
In addition, a metal film is formed by the same shadowing on the rounded portion R at the rear end portion of the ink chamber and the dry film resist opening portion of the flat portion, but two layers are formed after metal deposition is performed on the flat portion from the left and right directions. By setting the dry film resist thickness and the opening width so that the metal films overlap each other, the metal film can be formed on the entire opening part in the flat part, and the metal facing in the ink chamber 226 in the R part R The electrodes 201 and 201 can be connected to each other. Thereafter, the cover 210 having the ink supply holes 209 is adhered to complete the actuator 200.
[0010]
The actuator 200 formed in this way is driven in the share mode by applying a reverse-phase potential to the electrodes 201 and 201 facing each other through the partition, in the electrodes 201 and 201 formed on the partition forming the ink chamber 226. I do. That is, the ink chamber partition wall is deformed into a “<” shape at the boundary between the electrode forming region and the electrode non-forming region, and the ink chamber is utilized by utilizing the ink pressure change in the ink chamber 226 accompanying the volume change in the ink chamber 226. Ink droplets are ejected from the minute nozzles 212 of the nozzle plate 211 arranged at the tip.
[0011]
[Problems to be solved by the invention]
In the conventional inkjet head structure as described above, for example, as shown in FIG. 14, the active area contributing to ink ejection is only at the tip side from the ink supply hole 209, and the rear side including the ink supply hole 209 is the ink side. In addition, the rounded portion R and the flat electrode portion are electrically connected to the driving IC 40 as one external extraction electrode 202 by connecting two electrodes 201, 201 facing each other in the ink chamber 226. It is an area for performing.
[0012]
In such an ink jet head configuration, there is a problem that a portion other than the active area that originally contributes to ink ejection becomes very large, and the material cost is high, so that an inexpensive ink jet head cannot be manufactured.
[0013]
In addition, since it is necessary to extend the electrode in the ink chamber to a flat portion on a piezoelectric element such as PZT having a high dielectric constant, the capacitance increases, and when the actuator is driven, the applied drive waveform becomes dull, resulting in high speed driving. There was a problem that high-speed printing became difficult.
[0014]
The dullness of the applied drive waveform can be improved by increasing the applied voltage. However, by increasing the applied voltage, the amount of heat generated by driving the actuator 200 increases and the temperature of the actuator 200 increases, so that the ink viscosity changes. In addition, there is a problem that stable and highly accurate application cannot be performed, a driving IC 40 that can apply a high voltage is expensive, and it is difficult to reduce power consumption.
[0015]
For this reason, in a portion other than the active area of the ink chamber electrodes 201 and 201 of the actuator 200, a low dielectric film is formed in advance between the piezoelectric element 260 and the electrodes 201 and 201, thereby Measures were taken to reduce the capacitance as much as possible.
[0016]
However, for PZT having a low temperature Curie point of about 200 ° C., a very expensive ECR-CVD apparatus is required to form a low dielectric constant Si—N film by a low temperature process. There was a problem that the cost was increased and an inexpensive inkjet head could not be manufactured.
[0017]
Further, in order to solve the above-described problems, a structure in which the region for extending the ink chamber (ink supply hole) 110 and the ink chamber electrode 111 as shown in FIG. 18 is not required in the longitudinal direction of the piezoelectric element 260 is used. Is disclosed in JP-A-9-94954. That is, in this publication, the ink supply is provided with the ink chamber 110 at the rear end of the active area of the piezoelectric element 260, and the electrode 111 in the ink chamber is extended to the side of the ink supply side or the side of the ink discharge side and is connected to the driving IC 115. Electrical connection with the electrode 112 is performed. In this case, since there is no portion other than the active area of the actuator 200, the material cost of the piezoelectric element 260 can be reduced, but there still remains a problem with excess capacitance.
[0018]
Further, the ink chamber electrode 111 is bent at an angle of 90 ° to the side surface of the actuator, and the electrode is drawn out. For electrode drawing out to the side surface of the actuator, a wafer is formed like a partition wall electrode in the ink chamber 110. In this state, it is impossible to form the film by oblique vapor deposition, and it is necessary to obtain electrical continuity by simultaneously depositing a metal film on the ink chamber electrode 111 and the side surface of the actuator after the actuator is cut into small pieces.
[0019]
In order to reliably extend the two ink chamber electrodes 111 and 111 in a state of having electrical continuity on the side surface of the actuator, oblique vapor deposition from at least two directions is necessary. In order to separate the gaps, if resist patterning or patterning is not performed in advance, an electrode separation process using dicing or a YAG laser is required after drawing to a solid electrode, which makes the process very complicated and yields low yield. There is a problem that the production cost increases.
[0020]
The lead wiring can also be formed by other plating techniques, but there is a problem that the process becomes complicated because a patterning process or an electrode separation process is required as in the vapor deposition technique. In addition, the drawn electrode is also a curved surface portion drawn out from the ink chamber 110 to the side surface of the actuator, and there is a high possibility that the electrode will be disconnected in a later process or handling, resulting in a problem that the yield of production is lowered or environmental reliability is lowered. There was also.
[0021]
The present invention has been made in view of the above circumstances, and is an inkjet head capable of high-speed printing with a low material cost, easy to manufacture, suitable for mass production, inexpensive to manufacture, and an electrode connection structure thereof and an inkjet head. It aims at providing the manufacturing method of.
[0022]
[Means for Solving the Problems]
In the present invention, means for solving the above-described problems are configured as follows.
[0023]
  (1) External circuit on the opposite side of the droplet discharge surfaceAn inkjet head having an external connection electrode cross-section to which
  A plurality of grooves formed in a channel wafer polarized in the thickness direction;
  Actuator driving electrodes formed on both side surfaces of each of the plurality of grooves;
  In each of the plurality of grooves, a conductive adhesive filled so as to be electrically connected to the actuator driving electrode;
  A lead electrode formed separately from the actuator driving electrode and disposed inside each of the plurality of grooves so as to be covered with the conductive adhesive,
With
  The conductive adhesive and the lead electrode have a cut surface formed by cutting along a cross section of the external connection electrode, and the cut surface of the conductive adhesive and the lead electrode is connected to the external connection. Included in electrode cross sectionIt is characterized by that.
[0024]
In this configuration, the conductive resin filled in the ink chamber plays a role of electrically connecting the drive electrodes disposed facing the side surfaces of the ink chamber to each other and electrically connecting the lead electrode and the drive electrode.
[0025]
The lead electrode is exposed in the cross section of the rear end portion of the ink head, and plays a role of electrically connecting to an electrode that is electrically connected to the driving IC on the rear end surface. Therefore, conventionally, the ink chamber electrode has been drawn out of the ink chamber for mounting. However, it is not necessary, and the lead electrode can be directly contacted with the driving IC.
[0026]
Therefore, it is possible to manufacture a small inkjet head that requires almost no part other than the active area of the actuator. Thereby, a material cost can be reduced and a low-cost ink jet head can be provided.
[0027]
In addition, since the drive frequency can be improved by reducing the capacitance, high-speed printing can be realized, and the drive voltage can be reduced, so that the withstand voltage of the drive IC can be reduced, thereby reducing the drive IC cost and drive power consumption. Can be provided.
[0029]
  (2) Furthermore,The electrode connected to the driving IC can be brought into contact with both the lead electrode cross section and the conductive resin cross section. In the cross section of the external connection electrode where the electrode connected to the driving IC contacts, The resin also serves as a mechanical reinforcing member for the lead electrode.
[0030]
In addition, in a configuration in which only the cross section of the conductive resin is exposed on the rear end surface of the ink head, the metal filler may be mechanically damaged on the surface of the cut surface of the conductive resin, and microcracks may be generated or the metal filler may be detached. For this reason, even if an electrode that is in conduction with the driving IC is brought into contact with the cross section of the conductive resin, there is a risk of causing poor conduction or deterioration with time. In this configuration, a lead electrode having mechanical strength is provided. Therefore, such a problem does not occur.
[0031]
Therefore, compared with the item (1), the conduction between the electrode conducting to the driving IC and the driving electrode can be made more reliable, so that the production yield is improved in addition to the effect described in the item (1). Furthermore, it enables low-cost production. In addition, connection reliability can be ensured even over long-term use, and an inkjet head with a long product life can be realized.
[0032]
(3) The lead electrode is attached to the side surface or bottom surface of the ink chamber.
[0033]
In this configuration, in the cross section of the external connection electrode, the lead electrode is in close contact with the ink chamber constituent member having mechanical strength, so that the mechanical strength is strong and the contact with the electrode that is electrically connected to the driving IC. The risk of breakage is reduced. In addition, since the lead electrode is formed along the shape of the ink chamber, it is easy to fill the conductive resin, it is difficult to cause problems such as insufficient filling, and the external connection electrode can be manufactured stably. It becomes.
[0034]
Therefore, as compared with the items (1) and (2), it is possible to further ensure the conduction between the electrode that is in conduction with the driving IC and the driving electrode, and the damage of the lead electrode during production and the external Production defects of the connection electrode are reduced. Therefore, in addition to the effects described in the items (1) and (2), the production yield is improved, and further low-cost production is possible. In addition, connection reliability can be ensured even over long-term use, and an inkjet head with a long product life can be realized.
[0035]
(4) The lead electrode is a metal film formed by a vacuum deposition method.
[0036]
In this configuration, by using the vacuum vapor deposition method, it is possible to easily form the conductive lead electrode even in the vicinity of the groove bottom surface in the recessed region. Using a metal film prepared by a vacuum deposition method as a lead electrode is a very simple manufacturing method in a mass production process in which a plurality of ink jet heads are manufactured from a large area substrate at once.
[0037]
Further, the drive electrode is generally produced by vacuum deposition, and if the lead electrode is produced by vacuum deposition, a vacuum apparatus can be shared. Therefore, unnecessary capital investment is not required and the burden on the manufacturing cost is small, so that the cost of the inkjet head can be reduced. That is, it is possible to manufacture an inkjet head having the effects described above in the items (1), (2), (3), and (4) by a method suitable for mass production and at low cost.
[0038]
Furthermore, the vacuum deposition method is a method capable of producing the highest film formation speed in the vacuum process, and has a relatively high speed and a simple manufacturing process, so that the film stress is small and the possibility of peeling is low. A lead electrode that is small and can be made thick can be easily obtained. In addition, the said effect is exhibited notably by making a metal film into Cu film | membrane or Al film | membrane.
[0039]
Therefore, with this configuration, it is possible to provide an ink jet head that has a simple manufacturing process, good manufacturing yield, and low manufacturing costs.
[0040]
(5) The lead electrode is composed of a laminated film of at least two layers.
[0041]
Specifically, in this configuration, an auxiliary film having good adhesion to the ink chamber constituent member is formed on the ink chamber constituent member side, and a main film that can be easily thickened is laminated thereon to form an ink. It is possible to obtain a lead electrode that has good adhesion to the chamber constituent members and can be easily thickened. That is, by using a laminated film, it is possible to form a lead electrode that achieves both high-speed film-forming properties, thick film formation, and adhesion.
[0042]
Therefore, the contact area for connecting the electrode for electrical connection with the external connection electrode and the driving IC is wide, the electrical resistance due to the connection is reduced, the driving frequency can be improved, high-speed printing can be realized, and the driving voltage can be reduced. Therefore, the withstand voltage of the driving IC can be reduced, so that the driving IC cost can be reduced and the driving power consumption can be reduced.
[0043]
Furthermore, there is little risk of peeling off of the lead electrode due to film stress which is a concern due to thickening, production yield is improved, production cost can be reduced, and deterioration with time can be prevented.
[0044]
(6) The lead electrode is characterized in that a portion in contact with the conductive resin is made of the same material as the driving electrode constituent material.
[0045]
In this configuration, when the driving electrode and the lead electrode are electrically connected with the conductive resin in the external connection electrode portion, the electrical conduction characteristics of the electrode material and the conductive resin are the curing agent component of the conductive resin. Depending on the material and shape of the metal filler, the curing conditions, etc., the difference between the drive electrode and the conductive resin and between the lead electrode and the conductive resin is the same by using the same material for the drive electrode and the lead electrode. Since the electrical connection conditions are satisfied, the same optimum conditions can be used, and the same electrical connection is ensured between the driving electrode and the conductive resin and between the lead electrode and the conductive resin. Therefore, an inkjet printer with high electrical connection reliability can be provided.
[0046]
(7) The lead electrode is composed of a laminated film formed of a refractory metal as a first layer and Cu, Ag, and Al as a first layer from an inner surface of a channel groove in which the ink chamber is formed. Is 0.05 μm or more, and the thickness of the second layer is 1 μm or more and 50 μm or less.
[0047]
In this configuration, a titanium film having good adhesion to both the piezoelectric material and the metal film serving as the second layer is provided between the channel groove surface and the metal film so that the second layer film can be made free from the piezoelectric material due to the film stress. It plays a role of suppressing the peeling. It is sufficient that the thickness of the titanium film is 0.05 μm or more, and the thickness of the second layer film does not have a risk of peeling in the range of up to 50 μm.
[0048]
(8) The lead electrode is made of a refractory metal material embedded in the conductive resin.
[0049]
In this configuration, the lead electrode in the items (1) and (2) is embedded in the conductive resin by inserting a refractory metal material having a size equal to or smaller than the groove width and filling the ink chamber with the conductive resin. The refractory metal material thus formed is used as a lead electrode. Therefore, it is not necessary to produce a lead electrode by a vacuum process such as vacuum evaporation, and the manufacturing process can be reduced in cost.
[0050]
Further, since a refractory metal, which is difficult by vacuum vapor deposition, can be used as a lead electrode, a lead electrode having high mechanical strength and less risk of breakage can be easily obtained. Further, by using a refractory metal for the lead electrode, a connection method using metal diffusion bonding such as wire bonding can be used for electrical connection between the lead electrode and the electrode that is in conduction with the driving IC. Therefore, it is possible to provide an ink jet printer with high reliability of electrical connection by ensuring more reliable electrical connection between the lead electrode and the driving IC.
[0051]
(9) The electrode (drive electrode) that is electrically connected to the actuator drive IC is electrically connected to the lead electrode exposed in the cross section of the external connection electrode of the inkjet head.
[0052]
In this configuration, as in the items (1) and (2), the ink chamber electrode has conventionally been drawn out of the ink chamber for mounting. This is unnecessary and material costs can be reduced.
[0053]
In addition, since the drive frequency can be improved by reducing the capacitance, high-speed printing can be realized, and the drive voltage can be reduced, so that the withstand voltage of the drive IC can be reduced, thereby reducing the drive IC cost and drive power consumption. Can be reduced.
[0054]
(10) The electrode (actuator driving electrode) connected to the actuator driving IC is electrically connected to the lead electrode and the conductive resin electrode exposed on the cross section of the external connection electrode of the inkjet head. To do.
[0055]
In this configuration, as in the items (1) and (2), the conventional ink chamber electrode has been drawn out of the ink chamber for mounting, but this is no longer necessary and almost no part other than the active area of the actuator is required. Therefore, the material cost can be reduced.
[0056]
In addition, since the drive frequency can be improved by reducing the capacitance, high-speed printing can be realized, and the drive voltage can be reduced, so that the withstand voltage of the drive IC can be reduced, thereby reducing the drive IC cost and drive power consumption. Can be reduced.
[0057]
Furthermore, by connecting the conductive electrode to the actuator drive IC not only on the lead electrode cross section but also on the conductive resin cross section, an ink jet head that is durable for a long period of time compared to the item (9) can be obtained. It becomes possible to provide.
[0058]
(11) forming a plurality of independent actuator driving electrodes in each ink chamber for a channel wafer that has been polarized in the thickness direction and grooved at a predetermined pitch; A step of forming a lead electrode on the groove bottom surface or side surface of at least a portion where the external connection electrode is formed, a step of filling a conductive adhesive into the ink chamber of the portion serving as the external connection electrode, Curing the conductive adhesive, bonding the channel wafer and the cover wafer, and slicing the channel wafer so as to cut the conductive adhesive filling portion and the lead electrode portion; , Including.
[0059]
(12) The step of forming the lead electrode on the groove bottom surface and the side surface of the portion serving as the external connection electrode includes a first step of closing a groove upper opening portion other than the portion serving as the external connection electrode, and a vacuum process. And a second step of forming a lead electrode using the method.
[0060]
In this configuration, in addition to the effect described in the item (11), it is possible to manufacture an ink jet head with less unnecessary capacitance by a method suitable for mass production and capable of reducing the cost.
[0061]
(13) A step of forming a plurality of independent drive electrodes in each ink chamber on a channel wafer that has been polarized in the thickness direction and grooved at a predetermined pitch, and a portion that becomes an external connection electrode The step of depositing and forming the refractory metal member, the step of filling the ink chamber of the portion serving as the external connection electrode with a conductive adhesive, the step of curing the filled conductive adhesive, A step of bonding the channel wafer and the cover wafer; and a step of cutting the channel wafer into pieces so as to cut the conductive adhesive filling portion and the conductive lead electrode portion.
[0062]
In this configuration, the production of the lead electrode does not require a vacuum process, the production cost is reduced, and furthermore, it is possible to produce an inkjet head using a refractory metal as the lead electrode, which is impossible with vacuum deposition. Become.
[0063]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an inkjet head, an electrode connection structure, and an inkjet head manufacturing method according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0064]
(Embodiment 1)
Hereinafter, an inkjet head, an electrode connection structure, and an inkjet head manufacturing method according to Embodiment 1 of the present invention will be described with reference to the drawings.
[0065]
(Constitution)
FIG. 1 is a cross-sectional view showing an inkjet head. In this embodiment, an external connection electrode 30 is provided in a groove at the rear end of the actuator 20 made of a PZT piezoelectric element, and the external connection electrode 30 is electrically conductively bonded to a lead electrode 31 made of a metal film. The conductive resin member 32 is formed by filling a groove with an agent and curing it.
[0066]
The lead electrode 31 is an electrode provided on the bottom surface of the groove at the rear end of the ink jet head, and the conductive resin member 32 contains an Ag conductive filler based on an epoxy resin and has a property of exhibiting conductivity immediately after curing. At the rear end portion of the actuator 20, the lead electrode 31 and the conductive resin member 32 are exposed at the end surface where the lead electrode 31 and the conductive resin member 32 are cut.
[0067]
In the ink chamber 21, two actuator driving electrodes 22 </ b> A and 22 </ b> B are formed facing each other in the ink chamber 21, and the two driving electrodes 22 </ b> A and 22 </ b> B are interposed via the filled conductive resin 32. Is conducting. Further, a nozzle plate 25 having minute nozzles 24 is formed on the ink discharge surface 23 of the actuator 20, and the cover member 40 is disposed above the external connection electrode portion 30 at the rear end portion of the actuator 20. A pre-formed ink supply port 41 is arranged.
[0068]
With such a configuration, the ink chambers 21 arranged in an array are partitioned by the ink chamber partition walls 26 made of piezoelectric elements, and the drive electrodes 22A and 22B arranged in the upper half of each partition wall 26 are at the rear end of the inkjet head. In the external connection electrode portion 30, they are electrically connected via the conductive resin member 32 and are aggregated to have the same potential. The drive electrodes 22 </ b> A and 22 </ b> B are electrically connected to the lead electrode 31 through the conductive resin member 32.
[0069]
In this embodiment, the groove width of the ink chamber 21 is 77 μm and the groove depth is 300 μm. The drive electrodes 22A and 22B are Cu films having a thickness of 0.5 μm and a width in the groove depth direction of 150 μm. Further, the conductive resin member 32 is filled in the groove to the same height as the top of the ink chamber partition wall 26, and has a thickness of 0.7 mm in the longitudinal direction of the ink chamber 21.
[0070]
The lead electrode 31 is a Cu film, like the drive electrodes 22A and 22B, and has a thickness in the groove depth direction of 50 μm and a length in the groove longitudinal direction of 0.5 mm. The total length of the inkjet head is 3.3 mm, and the length of the active portion (the portion where the upper surface of the groove is blocked by the cover member 40), which is the portion that drives to discharge ink, is 1.15 mm.
[0071]
Note that the thickness of the drive electrodes 22A and 22B in the active portion is desirably 1 μm or less. This is because the greater the thickness of the drive electrodes 22A and 22B, the greater the mechanical restraint against the vibration of the ink gap 29 and the lower the ink droplet ejection performance.
[0072]
In this embodiment, the constituent material of the drive electrodes 22A and 22B and the lead electrode 31 is Cu, which is the same substance. This is because there is an optimum curing condition for each electrode material and conductive resin material when the liquid conductive resin embedded in the groove is cured and electrically connected with the electrode in close contact with each other. However, by using the same material as the constituent material of the drive electrodes 22A and 22B and the lead electrode 31, in the electrical connection at the interface between the conductive resin and the drive electrodes 22A and 22B and the conductive resin and the lead electrode 31, This is because the optimum curing conditions can be selected. For the lead electrode 31, the outermost layer material in contact with the conductive resin may be the same material as the drive electrode.
[0073]
Next, FIG. 2 is a diagram showing the connection between the inkjet head chip and the driving IC. From the same figure, the outer lead 52 formed on the TAB tape 51 conducted to the driving IC 50 is a cut exposed surface of the lead electrode 31 of the external connection electrode 30 and the conductive resin member 32 at the rear end of the actuator 20. In addition, they are electrically and mechanically connected via an ACF (Anisotropic Conductive Film) 53.
[0074]
In this embodiment, the lead electrode 31 cut surface and the conductive resin 32 cut surface are connected in the vicinity of the groove bottom surface, but connected to the cut surface of the lead electrode 31 and the entire cross section of the conductive resin. May be. Further, the connection is possible even if the connection is made only by the cut surface of the lead electrode 31.
[0075]
The cross-sectional area of the cut surface of the lead electrode 31 is 1 × 10.^-Five(Mm²In this case, the electrical connection of the driving IC 50 is more reliable.
[0076]
With such a configuration, the driving IC 50 and the driving electrodes 22A and 22B in the ink chamber 21 can be made conductive, and voltage application in an opposite phase is applied to the opposing driving electrodes 22A and 22B on the front and back of the ink chamber partition wall 26. As a result, the partition wall 29 serves as the actuator 20 that is driven in the shear mode to control the ink pressure in the ink chamber 21, thereby ejecting ink fine droplets from the nozzle 24.
[0077]
(Production method)
Next, a method for manufacturing the inkjet head will be described with reference to FIG. First, the first step is a step of forming the ink chamber 21 by half-dicating the piezoelectric element wafer 60 on one surface of the piezoelectric element 60 polarized in the thickness direction using a dicer dicing blade. Thus, a piezoelectric element wafer 60 having an ink chamber array as shown in FIG.
[0078]
The second step is a step of forming the lead electrode 31 on the bottom surface of the groove to be the external connection electrode by vacuum deposition. As shown in FIG. 3B, in this embodiment, a metal mask 55 having an opening width of 1 mm and an opening pitch of 4 mm is brought into intimate contact with the piezoelectric element wafer 60 of the ink chamber array, and the Cu from the groove bottom normal direction, that is, the arrow direction. The lead electrode 31 is formed by forming a Cu film having a width in the longitudinal direction of the groove of about 1 mm and a thickness of 50 μm on the bottom surface of the groove to be the external connection electrode. In this way, a piezoelectric element wafer as shown in FIG.
[0079]
The third step is a step of forming the drive electrodes 22A and 22B on the upper half of the ink chamber partition wall 26 by vacuum vapor deposition. In this embodiment, Cu metal is obliquely deposited from a direction perpendicular to the longitudinal direction of the ink chamber 21.
[0080]
By performing this operation from the left and right directions with respect to the longitudinal direction of the ink chamber 21, metal electrodes (driving electrodes 22A and 22B) are formed on the surface of the ink chamber partition wall 26, and the shadow effect of each ink chamber partition wall is formed. The metal film is formed up to about ½ in the depth direction of the ink chamber 21. Thus, a Cu film having a thickness of 0.5 μm is formed on the upper half of all the ink chamber partition walls of the ink chamber array, and a piezoelectric element wafer as shown in FIG. 3D can be formed.
[0081]
The fourth step is a step of forming the conductive resin member 32 by pouring a conductive adhesive into the premises of the portion to be the external electrode and further curing it. Here, a liquid conductive adhesive in a direction orthogonal to the array of the ink chambers 21 of the piezoelectric element wafer 60 is applied and supplied in a single character on the ink chamber 21 and the ink chamber partition wall 26 with a width of 1 mm using a dispenser or the like. To do. Next, the piezoelectric element wafer 60 is heated to cure the conductive adhesive and form the conductive resin member 32. In this way, a piezoelectric element wafer 60 as shown in FIG.
[0082]
The fifth step is a step of removing unnecessary electrodes on the ink chamber partition wall 26. Here, the conductive resin member, the lead electrode, and the drive electrode on the ink chamber partition wall 26 are polished and removed by using a grinder so that the conductive resin member in each ink chamber 21 is not electrically connected. In this way, a piezoelectric element wafer 60 as shown in FIG.
[0083]
The sixth step is a step of bonding a cover wafer 65 made of a piezoelectric element in which a counterbore for the ink supply port is previously formed by sandblasting to the piezoelectric element wafer 60 manufactured in the fifth step. As shown in FIG. 4, after the cover wafer 65 is coated with a dry resist on the entire surface, the portion where the counterbore 66 for the ink supply port 41 is formed is removed by selectively chemically etching the resist, Sand blasting is performed to form a counterbore 66 having a desired pattern.
[0084]
Then, the piezoelectric element wafer 60 on which the ink chamber array is formed and the cover wafer 65 are bonded with a commercially available adhesive. At this time, alignment is performed so that the portion filled with the conductive resin comes to the center portion of the counterbore portion 66 for the ink supply port 41 of the cover wafer 65, and the two are bonded as shown in the sectional view of FIG. .
[0085]
The seventh step is a step of dividing the piezoelectric element wafer 60 bonded in the sixth step into individual actuators 20. Here, in the dicing line indicated by the broken line XX in FIG. 4, the dicing blade of the dicer is used in the counterbore 66 portion for the ink supply port of the cover wafer 65, the conductive resin filling portion and the lead electrode portion of the ink chamber wafer 60. , Into individual actuators.
[0086]
At this time, a cut surface of the conductive resin is exposed on the side surface of the actuator on the cut surface, and becomes an electrode for electrical connection with an external circuit conducted to a driving IC connected later, and the actuator 20 is completed. In addition, an ink discharge surface is formed by a dicing line indicated by a broken line YY in FIG.
[0087]
(Modification)
In the above-described embodiment, the example in which the lead electrode 31 is selectively disposed only on the bottom surface of the groove corresponding to the external connection electrode portion has been described. However, the lead electrode 31 is not necessarily disposed selectively, and as illustrated in FIG. The lead electrode 31 may be formed over the entire groove bottom surface. In this case, as compared with the ink jet head of the first embodiment, unnecessary capacitance increases, which is disadvantageous in performing high-speed driving. However, since the masking process can be omitted, the manufacturing cost is low. An inexpensive inkjet head can be obtained.
[0088]
Further, although the Cu film is formed by depositing the lead electrode 31 by vacuum deposition, it is not always necessary to have this configuration, and it is formed by a plating method, a vacuum process method, or a vacuum process method and a plating method. Any conductive film may be used.
[0089]
The conductive film manufactured by the above method can be selectively formed only on the external connection electrode portion. By selectively forming a conductive film, generation of unnecessary capacitance can be reduced, and driving frequency can be improved, so that high-speed printing can be realized. In addition, since the driving voltage can be reduced, the withstand voltage of the driving IC can be reduced, so that the driving IC cost can be reduced and the driving power consumption can be reduced.
[0090]
In addition, the conductive film produced by the above method is a thick film having uniform characteristics with little variation in electric resistance, film thickness, and capacitance due to the film formation area. Can get to. Therefore, it is possible to provide a device with reduced manufacturing cost and less variation in electrical resistance and capacitance between channels.
[0091]
In the present embodiment, the lead electrode 31 is a single layer film, but it is not necessarily a single layer film, and may be a laminated film as shown in FIG. In particular, as the first layer film 33 in contact with the ink chamber constituting member, a refractory metal such as Ti, Ta, W, and Mo is formed with a thickness of 0.05 μm or more, and then the second layer film 34 is inexpensive, By using a laminate of Al and Cu having good vapor deposition rate and good electrical conductivity as the lead electrode 31, it is possible to obtain a good lead electrode 31 with no fear of peeling even if it becomes a thick film.
[0092]
Similarly, a second layer can be formed by electroless plating on a Ni film formed by a vacuum process as a first layer film in contact with the ink chamber 21 to form a lead electrode. In this case, the lead electrode which is a thick film can be formed by an inexpensive and quick method.
[0093]
In the present embodiment, a configuration is shown in which the lead electrode 31 is formed only on the bottom surface of the groove. This is because the film formation time of the lead electrode 31 can be shortened as much as possible by performing vacuum deposition from a direction perpendicular to the groove bottom surface. However, the lead electrode 31 formed in a U shape along the groove bottom surface and the groove side surface may be used without being limited to this configuration. As an example thereof, as shown in FIG. 7, a lead electrode 31 is provided on one side surface of the groove side surface of the head rear end.
[0094]
(Embodiment 2)
Embodiment 2 of the present invention will be described below with reference to the drawings.
(Constitution)
FIG. 8 is a cross-sectional view showing a cross section of the inkjet head. In the present embodiment, the external connection electrode 30 includes a conductive resin member 32 filled in the ink chamber 21 near the rear end portion of the actuator 20 made of a PZT piezoelectric element and a lead attached to the bottom surface of the ink chamber 21. The lead electrode 31 is composed of an electrode 31 and is extended to the rear end face of the head. The cross section of the lead electrode 31 is exposed on the head rear end surface opposite to the ink ejection surface, but the conductive resin member 32 is not exposed.
[0095]
The external connection electrode 30 includes a lead electrode 31 made of a metal film and a conductive resin member 32 formed by filling a groove with a conductive adhesive and curing it. The lead electrode 31 is an electrode provided on the bottom surface of the groove at the rear end of the inkjet head, and the conductive resin member 32 contains an Ag conductive filler based on an epoxy resin and has a property of exhibiting conductivity immediately after curing. .
[0096]
At the rear end portion of the actuator 20, the cut surface of the lead electrode 31 is exposed at the end surface where the lead electrode 31 is cut.
[0097]
Two actuator drive electrodes 22A and 22B are formed in the ink chamber 21 in a state of facing each other in the ink chamber 21, and the two drive electrodes 22A and 22B are interposed via the filled conductive resin member 32. Conducted. Further, a nozzle plate 25 having minute nozzles 24 is formed on the ink discharge surface 23 of the actuator 20, and the cover member 40 is disposed above the external connection electrode portion 30 at the rear end portion of the actuator 20. A pre-formed ink supply port 41 is arranged.
[0098]
With such a configuration, the ink chambers 21 arranged in an array are partitioned by ink chamber partition walls 26 made of piezoelectric elements, and the drive electrodes 22A and 22B arranged in the upper half of each partition wall 26 are arranged at the rear end of the inkjet head. In a certain external connection electrode part 30, they are electrically connected via the conductive resin member 32 and are aggregated to have the same potential. The drive electrodes 22A and 22B are electrically connected to the lead electrode 31 through the conductive resin member 32.
[0099]
In this embodiment, the groove width of the ink chamber 21 is 77 μm and the groove depth is 300 μm. The drive electrodes 22A and 22B are Cu films having a thickness of 0.5 μm and a width in the groove depth direction of 150 μm. The lead electrode 31 is a Cu film, like the drive electrodes 22A and 22B, and has a thickness in the groove depth direction of 50 μm and a length in the groove longitudinal direction of 0.7 mm. The total length of the inkjet head is 3.3 mm, and the length of the active portion (the portion where the upper surface of the groove is closed by the cover member), which is the portion that performs the drive for discharging ink, is 1.15 mm.
[0100]
(Production method)
The manufacturing method of the inkjet head in this embodiment is the same as that of the previous embodiment.
The first to third steps in the description of the manufacturing method are the same and will not be described.
[0101]
The fourth step of the ink jet head manufacturing method of the present embodiment is a step of filling the groove with a conductive adhesive. Here, a liquid conductive adhesive is dispensed from both ends of the lead electrode formed on the groove bottom surface (arrows in FIG. 9) in a direction orthogonal to the array of the ink chambers 21 of the piezoelectric element wafer 60 using a dispenser or the like. Then, it is applied and supplied to the character on the ink chamber 21 and the ink chamber partition with a width of 1 mm. Next, the piezoelectric element wafer is heated to cure the conductive adhesive, thereby forming the conductive resin member 32.
[0102]
The fifth step is a step of removing unnecessary electrodes on the ink chamber partition wall 26. Here, the conductive resin member, the lead electrode, and the drive electrode on the ink partition wall 26 are polished and removed by using a grinding machine so that the conductive resin member 32 in each ink chamber 21 is not electrically connected.
[0103]
The sixth step is a step of adhering a cover wafer 65 made of a piezoelectric element in which a counterbore 66 for the ink supply port 41 is formed in advance by sandblasting to the piezoelectric element wafer 60 manufactured in the fifth step. . After the dry resist is applied to the entire surface of the cover wafer 65, the portion where the counterbore 66 for the ink supply port 41 is formed is removed by selective chemical etching of the resist, and sandblasting is performed to obtain a desired portion. A counterbore of the pattern is formed.
[0104]
Then, the piezoelectric element wafer 60 on which the ink chamber 21 array is formed and the cover wafer 65 are bonded with a commercially available adhesive. At this time, alignment is performed so that the portion filled with the conductive resin comes directly above the counterbore portion 66 for the ink supply port 41 of the cover wafer 61, and the two are bonded together as shown in FIG. 9B. .
[0105]
The seventh step is a step of dividing the wafer bonded in the sixth step into individual actuators. Here, in the dicing line indicated by the broken line XX in FIG. 4, the individual feed actuator portions 66 of the cover wafer 65 and the lead electrode portions 31 of the ink chamber wafer 60 are individually connected to the individual actuators by the dicing blade of the dicer. Small pieces.
[0106]
At this time, the cut surface of the lead electrode 31 is exposed on the side surface of the actuator on the cut surface and becomes an electrode for electrical connection with an external circuit conducted to a driving IC connected later, and the actuator 20 is completed. In addition, an ink discharge surface is formed by a dicing line indicated by a broken line YY in FIG.
[0107]
(Embodiment 3)
Embodiment 3 of the present invention will be described below with reference to the drawings.
(Constitution)
FIG. 10 is a cross-sectional view of the ink jet head. An external connection electrode 30 is provided in the groove at the rear end of the actuator 20 made of a PZT piezoelectric element. The external connection electrode 30 fills the groove with a lead electrode 31 made of a metal wire and a conductive adhesive. The conductive resin member 32 is formed by curing.
[0108]
The lead electrode 31 is a wire made of a refractory metal embedded in a conductive resin, and the wire diameter is about 30 μm. The conductive resin member 32 contains Ag conductive filler based on an epoxy resin, and has a property of exhibiting conductivity immediately after curing.
[0109]
In the rear end portion of the actuator 20, the lead electrode 31 and the conductive resin member 32 are exposed at the end surface where the lead electrode 31 and the conductive resin member 32 are cut.
[0110]
In the ink chamber 21, two actuator drive electrodes 22 </ b> A and 22 </ b> B are formed facing each other in the ink chamber 21, and the two drive electrodes 22 </ b> A and 22 </ b> B are interposed via the filled conductive resin 32. Conductivity is obtained. Further, a nozzle plate 25 having minute nozzles 24 is formed on the ink discharge surface 23 of the actuator 20, and the cover member 40 is disposed above the external connection electrode portion 30 at the rear end portion of the actuator 20. A pre-formed ink supply port 41 is arranged.
[0111]
With such a configuration, the ink chambers 21 arranged in an array are partitioned by the ink chamber partition walls 26 made of piezoelectric elements, and the drive electrodes 22A and 22B arranged in the upper half of each partition wall 26 are at the rear end of the inkjet head. In the external connection electrode portion 30, they are electrically connected via the conductive resin member 32 and are aggregated to have the same potential. The drive electrodes 22 </ b> A and 22 </ b> B are electrically connected to the lead electrode 31 through the conductive resin member 32.
[0112]
In this embodiment, the groove width of the ink chamber 21 is 77 μm and the groove depth is 300 μm. The drive electrodes 22A and 22B are Cu films having a thickness of 0.5 μm and a width in the groove depth direction of 150 μm. Further, the conductive resin member 32 is filled in the groove to the same height as the top of the ink chamber partition wall, and has a thickness of 0.5 mm in the longitudinal direction of the ink chamber. The lead electrode 31 uses a Ta metal wire, and the diameter of the wire is about 30 μm. The total length of the ink jet head is 3.3 mm, and the length of the active portion (the portion where the upper surface of the groove is blocked by the cover member), which is a portion that performs the drive for discharging ink, is 1.15 mm.
[0113]
Further, the diameter of the metal wire to be the lead electrode 31 is desirably 15 to 60 mm. If the diameter is 15 mm or less, the contact area between the driving electrodes 22A and 22B that are in conduction with the driving IC is insufficient, and there is a risk of causing a conduction failure. There is a risk of lowering. On the other hand, when the diameter is 60 μm or more, the filling of the conductive adhesive into the groove becomes insufficient, voids are generated in the conductive resin, and the mechanical strength may be reduced, which may cause deterioration with time. is there. Note that the electrical connection with the driving IC is the same as that in the previous embodiment, and a description thereof will be omitted.
[0114]
(Production method)
Next, a method for manufacturing the inkjet head will be described with reference to FIG. The first step is a step of forming the ink chamber 21 by half-dicing the piezoelectric element wafer 60 on one surface of the piezoelectric element wafer 60 polarized in the thickness direction using a dicer dicing blade. Thus, the piezoelectric element wafer 60 having the ink chamber array shown in FIG.
[0115]
The second step is a step of forming the drive electrodes 22A and 22B on the upper half of the ink chamber partition wall 26 by vacuum vapor deposition. In this embodiment, Cu metal is obliquely deposited from a direction perpendicular to the longitudinal direction of the ink chamber 21.
[0116]
By performing this operation from the left and right directions with respect to the longitudinal direction of the ink chamber 21, metal electrodes (driving electrodes 22A and 22B) are formed on the surface of the ink chamber partition walls 26, and shadowing of each ink chamber partition wall 26 is performed. Due to the effect, the metal film is formed up to about ½ in the depth direction of the ink chamber 21. In this manner, a Cu film having a thickness of 0.5 μm is formed on the upper half of all the ink chamber partition walls 29 in the ink chamber array. As a result, a piezoelectric element wafer 60 as shown in FIG.
[0117]
The third step is a step of immersing a metal wire that becomes the lead electrode 31 in the ink chamber 21. In this step, as shown in FIG. 11 (c), a plurality of tungsten wires arranged at a pitch equal to the groove pitch are placed in parallel with the groove traveling direction, and then placed in the groove. Align and immerse toward the bottom of the groove. As a result, a piezoelectric element wafer 60 as shown in FIG.
[0118]
The fourth step is a step of forming a conductive resin member 32 by pouring a conductive adhesive into a groove of a portion to be an external electrode and further curing it. Here, a liquid conductive adhesive in a direction orthogonal to the array of the ink chambers 21 of the piezoelectric element wafer 60 is applied and supplied in a single character on the ink chamber 21 and the ink chamber partition wall 26 with a width of 1 mm using a dispenser or the like. To do.
[0119]
Next, the piezoelectric element wafer 60 is heated to cure the conductive adhesive and form the conductive resin member 32. In this way, a piezoelectric element wafer 60 as shown in FIG.
[0120]
The following fifth to seventh steps are the same as the manufacturing method described in the first embodiment, and thus the description thereof is omitted.
[0121]
By the way, in the present invention, the conductive resin member 32 is filled in the ink chamber 21 in order to make both the drive electrodes 22A and 22B in the ink chamber 21 conductive. Accordingly, in each of the above embodiments, for example, as shown in FIGS. 12A and 12B, the conductive resin member 32 in the ink chamber 21 in the portion facing the ink supply port 41 of the cover member 40 is formed in a concave cross section. Then, a gap C that faces the ink supply port 41 can be formed in that portion to improve air leakage.
[0122]
For example, the gap C can be formed on the inclined surface S in which the conductive resin member 32 is formed in a slope shape toward the bottom of the ink chamber 21 and the cross section thereof is formed in a concave shape. In other words, the concave inclined surface S is formed so as to rise obliquely upward from the bottom of the ink chamber 21 and to face the ink supply port 41.
[0123]
By forming such a gap C, air entering the ink chamber 21 from the nozzle 24 of the nozzle plate 25 is guided upward by the concave inclined surface S and smoothly discharged to the ink supply port 41. be able to. That is, the inclined surface S formed in a concave shape functions as a guide wall that guides air to the ink supply port 41. Accordingly, it is possible to effectively prevent the discharge performance from being deteriorated due to the stagnation of air in the ink chamber 21 and the variation in discharge between the nozzle where the air is generated and other nozzles, thereby stabilizing the discharge operation. And high print quality can be maintained.
[0124]
The effect of preventing the retention of air by forming such a gap C is apparent when compared with the configuration shown in FIGS. 13A and 13B, for example. That is, in this comparative example, the conductive resin 110 is filled in the rear end portion of the ink chamber 126 as a sealing member for preventing the ink from coming off.
[0125]
Of course, since both the electrodes 127 and 128 can be made conductive also by the conductive resin 110 filled for sealing in this way, the present invention can also adopt such a configuration. However, in this case, only the rear end portion of the ink chamber 126 is filled with the conductive resin 110, and no void portion that faces the ink supply port 131 of the cover member 130 is formed.
[0126]
Accordingly, the air that has entered the ink chamber 126 from the nozzle 124 of the nozzle plate 125 stays in the front part of the conductive resin 110, and the air pool H is likely to be generated. Dispersion of discharge is likely to occur, and printing quality is liable to deteriorate. Such difficulties in the comparative example can be solved by the configuration shown in FIG.
[0127]
It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that improvements and changes can be made as appropriate according to the use environment, use conditions, etc., without departing from the spirit of the present invention.
[0128]
【The invention's effect】
As apparent from the above description, the present invention has the following effects.
[0129]
According to the first aspect of the present invention, the conductive resin filled in the ink chamber causes the driving electrodes disposed opposite to the side surfaces of the ink chamber to conduct with each other and also causes the lead electrode and the driving electrode to conduct. The lead electrode is exposed in the cross section of the rear end portion of the ink head, and is electrically connected to an electrode that is electrically connected to the driving IC on the rear end surface.
[0130]
Therefore, the conventional ink chamber electrode has been drawn out of the ink chamber for mounting, but it is not necessary, and the lead electrode can be brought into direct contact with the driving IC.
[0131]
Therefore, it is possible to produce a small ink jet head that requires almost no part other than the active area of the actuator. Thereby, a material cost can be reduced and a low-cost inkjet head can be provided.
[0132]
Moreover, since the drive frequency can be improved by reducing the capacitance, high-speed printing can be realized. Further, since the drive voltage can be reduced, the withstand voltage of the drive IC can be reduced, so that the drive IC cost can be reduced, and an ink jet head with reduced drive power consumption can be provided.
[0133]
  further,The lead electrode cross section and the conductive resin cross section are exposed in the cross section of the external connection electrode that becomes the rear end surface of the ink jet head, so that the electrode that is electrically connected to the driving IC contacts the cross section of the lead electrode and the conductive resin. It becomes possible to make it.
[0134]
The conductive resin also serves as a mechanical reinforcing member for the lead electrode in the cross section of the external connection electrode that is in contact with the electrode that is electrically connected to the driving IC. In the configuration where only the cross section of the conductive resin is exposed on the rear end surface of the ink head, the metal filler may be mechanically damaged on the surface of the cut surface of the conductive resin, and microcracks may be generated or the metal filler may be detached. For this reason, there is a risk of causing poor conduction or deterioration over time even if an electrode that is in conduction with the driving IC is brought into contact with the cross section of the conductive resin. However, in this configuration, a lead electrode with mechanical strength is used. Since it is provided, such a problem does not occur.
[0135]
Therefore, in comparison with the first aspect of the invention, since the conduction between the driving electrode and the driving electrode can be made more reliable, in addition to the effect described in the first aspect, the production yield can be increased. Improved and enables low-cost production. In addition, connection reliability can be ensured even over long-term use, and an ink jet head with a long product life can be realized.
[0136]
  Also,The lead electrode is attached to the side or bottom of the ink chamber, and the lead electrode is provided at the interface between the conductive resin and the ink chamber constituent member. The mechanical strength of the ink chamber constituting member is high, and the contact between the driving IC and the conductive electrode is less likely to be damaged.
[0137]
In addition, since the lead electrode is formed along the shape of the ink chamber, it is easy to fill the conductive resin, it is difficult to cause problems such as insufficient filling, and the external connection electrode can be manufactured stably. It becomes.
[0138]
Therefore, in comparison with the first and second aspects of the invention, it is possible to ensure the conduction between the electrode connected to the driving IC and the driving electrode, and damage of the lead electrode during production and the external connection electrode. Production defects are reduced. Therefore, in addition to the effects described in the inventions of claims 1 and 2, the production yield is improved, and further low-cost production is possible. In addition, connection reliability can be ensured even over long-term use, and an inkjet head with a long product life can be realized.
[0139]
  If you use vacuum deposition,It is possible to easily form the conductive lead electrode even in the vicinity of the groove bottom surface in the recessed area. Using a metal film prepared by a vacuum deposition method as a lead electrode is a very simple manufacturing method in a mass production process in which a plurality of inkjet heads are manufactured collectively from a large area substrate.
[0140]
Further, the drive electrode is generally manufactured by vacuum deposition, and if the lead electrode is manufactured by a vacuum process, the vacuum apparatus can be shared. Therefore, unnecessary capital investment is not required and the burden on the manufacturing cost is small, so that the cost of the ink jet head can be reduced. In other words, the ink jet head having the above-described effects can be manufactured at a low cost by a method suitable for mass production.
[0141]
Furthermore, the vacuum deposition method is the method that can produce the fastest film formation speed in the vacuum process, and the film thickness is reduced by the relatively high-speed and simple manufacturing process. Can be obtained.
[0142]
The vacuum deposition method is the method that can produce the fastest film formation speed in the vacuum process, and the metal film produced by the vacuum deposition method has a small film stress, so there is little possibility of peeling, so a thick film Can be easily obtained.
[0143]
In addition, the said effect can be exhibited more notably by making a metal film into Cu film | membrane or Al film | membrane. Therefore, with such a configuration, it is possible to provide an ink jet head that is easy to manufacture, has a good manufacturing yield, and has a low manufacturing cost.
[0144]
  Claim2According to the present invention, the lead electrode constituting the external electrode at the rear end portion of the ink chamber has a laminated structure of two or more layers, and specifically, the ink chamber constituent member has an adhesive property with the ink chamber constituent member. By forming a good auxiliary film and laminating a main film that can be easily thickened on top of it, it is possible to obtain a lead electrode that has good adhesion to the ink chamber components and that can be easily thickened. Become. That is, by using a laminated film, it is possible to form a lead electrode that achieves both high-speed film-forming properties, thick film formation, and adhesion.
[0145]
Therefore, the contact area for connecting the electrode for electrical connection with the external connection electrode and the driving IC is widened, the electrical resistance due to the connection is reduced, and the driving frequency can be improved, so that high-speed printing can be realized.
[0146]
Since the driving voltage can be reduced and the withstand voltage of the driving IC can be reduced, the driving IC cost can be reduced and the driving power consumption can be reduced.
[0147]
Furthermore, there is little possibility of peeling of the lead electrode due to film stress which is a concern due to thickening, production yield is improved, production cost can be reduced, and deterioration with time can be effectively prevented.
[0148]
  Claim3According to the above, the portion of the lead electrode that contacts the conductive resin is made of the same material as the driving electrode constituent material.RuTherefore, in the case where the driving electrode and the lead electrode are electrically communicated with the conductive resin in the electrode portion for external connection, the electrical conduction characteristics of the electrode material and the conductive resin are the curing agent component of the conductive resin, the metal filler material However, by using the same material for the drive electrode and the lead electrode, the electrical connection conditions between the drive electrode and the conductive resin and between the lead electrode and the conductive resin are the same. Therefore, the same optimum conditions can be used, and the same electrical connection is ensured between the driving electrode and the conductive resin and between the lead electrode and the conductive resin. Therefore, an inkjet printer with high electrical connection reliability can be provided.
  Claim4According to the above, the lead electrode is a laminated film, and is composed of a laminated film in which the first layer is made of a refractory metal and the second layer is made of Cu, Ag, Al from the inner surface of the channel groove, and the thickness of the first layer is 0.05 μm or more. Since the thickness of the second layer is not less than 1 μm and not more than 50 μm, a titanium film having good adhesion to both the piezoelectric material and the metal film to be the second layer is provided between the channel groove surface and the metal film. It plays the role of suppressing peeling from the piezoelectric material due to the film stress of copper. It is sufficient that the thickness of the first layer film is 0.1 μm or more, and there is no possibility of peeling when the thickness of the second layer film is in the range of 50 μm.
[0149]
  Claim5According to the above, since the refractory metal material is used as the lead electrode, it is not necessary to manufacture the lead electrode by a vacuum process such as vacuum deposition, and the cost of the manufacturing process can be reduced.
[0150]
In addition, since a refractory metal that is difficult in vacuum deposition can be used as the lead electrode, a lead electrode having high mechanical strength and less risk of breakage can be easily obtained. Further, by using a refractory metal for the lead electrode, a connection method using metal diffusion bonding such as wire bonding can be used for electrical connection between the lead electrode and the electrode that is in conduction with the driving IC.
[0151]
Therefore, it is possible to provide an ink jet printer with high reliability of electrical connection by ensuring more reliable electrical connection between the lead electrode and the driving IC.
[0152]
  Claim6Since the drive electrode (conductive to the actuator drive IC) is electrically connected to the cross section of the lead electrode exposed at the rear end surface of the ink chamber, the conventional ink chamber electrode is mounted as in the first aspect. For this reason, it has been drawn out of the ink chamber, but this is no longer necessary, and the parts other than the active area of the actuator are almost unnecessary, and material costs can be reduced.
[0153]
In addition, since the drive frequency can be improved by reducing the capacitance, high-speed printing can be realized, and the drive voltage can be reduced, so that the withstand voltage of the drive IC can be reduced. Reduction of power consumption can be realized.
[0154]
  Claim7According to the first aspect of the present invention, the drive electrode (conductive to the actuator drive IC) is electrically connected to both the cross section of the lead electrode and the cross section of the conductive resin exposed on the rear end surface of the ink chamber of the ink jet head. Similarly to the above, the conventional ink chamber electrode has been drawn out of the ink chamber for mounting, but it is not necessary, and parts other than the active area of the actuator are almost unnecessary, and the material cost can be reduced. In addition, since the drive frequency can be improved by reducing the capacitance, high-speed printing can be realized, and the drive voltage can be reduced, so that the withstand voltage of the drive IC can be reduced. Reduction of power consumption can be realized.
[0155]
In addition, the drive electrode (conductive to the actuator drive IC) is electrically connected not only to the cross section of the lead electrode but also to the cross section of the conductive resin. A head can be provided.
[0156]
  Claim8According to claim 1, through a series of steps,5The ink jet head having the effect described in the above can be manufactured by a method suitable for mass production and cost reduction.
[0157]
  Claim9According to the first step, the step of forming the lead electrode includes a first step of closing the groove upper opening portion other than the portion to be the external connection electrode, and a second step of forming the lead electrode using a vacuum process. Including claims8In addition to the effects of the present invention, an ink jet head with less unnecessary capacitance can be manufactured by a method suitable for mass production and capable of reducing the cost.
[0158]
  Claim10According to the above, a series of processes does not require a vacuum process in the production of the lead electrode, reduces the manufacturing cost, and further produces an inkjet head using a refractory metal as the lead electrode, which is impossible by vacuum deposition. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an ink jet head according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of an ink jet head connected to the driving IC.
FIG. 3 is a cross-sectional view for explaining the method for manufacturing the ink jet head.
FIG. 4 is another sectional view of the same.
FIG. 5 is a sectional view showing a modification of the inkjet head.
FIG. 6 is a cross-sectional view showing another modification.
FIG. 7 is a cross-sectional view showing still another modification example.
FIG. 8 is a cross-sectional view of an ink jet head according to a second embodiment of the present invention.
FIG. 9 is a cross-sectional view for explaining the method for manufacturing the ink jet head.
FIG. 10 is a cross-sectional view showing an ink jet according to Embodiment 3 of the present invention.
FIG. 11 is a cross-sectional view for illustrating the same manufacturing method.
FIG. 12 is an explanatory diagram in the case where a gap facing the ink supply port is formed in a conductive resin in the ink jet head according to the present invention.
FIG. 13 is an explanatory diagram of a comparative example when no void is formed.
FIG. 14 is a cross-sectional view showing a structure of a conventional ink jet head and an electrode connecting method.
FIG. 15 is a cross-sectional view showing another example.
FIG. 16 is a cross-sectional view showing a different example.
FIG. 17 is a perspective view for explaining the method for manufacturing the inkjet head.
FIG. 18 is a cross-sectional view showing another ink jet head structure and electrode connection method.
[Explanation of symbols]
20-actuator
21-Ink chamber
22A, 22B-electrodes (actuator drive electrodes)
30-Electrode for external connection
31-lead electrode
32-conductive resin member

Claims (10)

An inkjet head having an external connection electrode cross section in which an external circuit is connected to the opposite side of the liquid droplet ejection surface,
A plurality of grooves formed in a channel wafer polarized in the thickness direction;
Actuator driving electrodes formed on both side surfaces of each of the plurality of grooves;
In each of the plurality of grooves, a conductive adhesive filled so as to be electrically connected to the actuator driving electrode;
A lead electrode formed separately from the actuator driving electrode and disposed inside each of the plurality of grooves so as to be covered with the conductive adhesive,
With
The conductive adhesive and the lead electrode have a cut surface formed by cutting along a cross section of the external connection electrode, and the cut surface of the conductive adhesive and the lead electrode is connected to the external connection. Included in the electrode cross section , and
The ink jet head according to claim 1, wherein the lead electrode is a metal film formed to be attached to a side surface or a bottom surface of an ink chamber and thicker than the actuator driving electrode . The inkjet head according to claim 1, wherein the lead electrode is formed of a laminated film of at least two layers. The inkjet head according to claim 1, wherein the lead electrode is made of the same material as the driving electrode constituent material at a portion in contact with the conductive resin. The lead electrode is composed of a laminated film formed of a refractory metal as a first layer and Cu, Ag, and Al as a second layer from an inner surface of a channel groove in which the ink chamber is formed. The inkjet head according to any one of claims 1 to 3, wherein the second layer has a thickness of 05 µm or more and a thickness of the second layer of 1 µm or more and 50 µm or less. An inkjet head having an external connection electrode cross section in which an external circuit is connected to the opposite side of the liquid droplet ejection surface,
A plurality of grooves formed in a channel wafer polarized in the thickness direction;
Actuator driving electrodes formed on both side surfaces of each of the plurality of grooves;
In each of the plurality of grooves, a conductive adhesive filled so as to be electrically connected to the actuator driving electrode;
A lead electrode formed separately from the actuator driving electrode and disposed inside each of the plurality of grooves so as to be covered with the conductive adhesive,
With
The conductive adhesive and the lead electrode have a cut surface formed by cutting along a cross section of the external connection electrode, and the cut surface of the conductive adhesive and the lead electrode is connected to the external connection. Included in the electrode cross section, and
The inkjet head according to claim 1, wherein the lead electrode is made of a refractory metal material embedded in the conductive resin. An electrode connection structure for an inkjet head according to any one of claims 1 to 5,
An electrode connection structure for an ink jet head, wherein an electrode (drive electrode) connected to an actuator driving IC is electrically connected to a lead electrode exposed on a cross section of the electrode for external connection of the ink jet head. An electrode connection structure for an inkjet head according to any one of claims 1 to 5,
An ink jet head characterized in that an electrode (actuator driving electrode) connected to an actuator driving IC is electrically connected to a lead electrode and a conductive resin electrode exposed on a cross section of an external connection electrode of the ink jet head. Electrode connection structure. The manufacturing method of the inkjet head of any one of Claims 1-4. Because
Forming a plurality of independent actuator driving electrodes in each ink chamber on a channel wafer that has been polarized in the thickness direction and grooved at a predetermined pitch; and
Forming a lead electrode made of a metal film having a thickness larger than that of the actuator driving electrode on a groove bottom surface or a groove side surface of at least a portion of the channel wafer groove where the external connection electrode is formed;
Filling a conductive adhesive into an ink chamber of a portion to be the external connection electrode;
Curing the filled conductive adhesive;
Bonding the channel wafer and the cover wafer;
And a step of cutting the channel wafer into pieces so as to cut the conductive adhesive filling portion and the lead electrode portion. Forming a lead electrode on the groove bottom surface and the groove side surface of the portion to be the external connection electrode;
A first step of closing the groove upper opening portion other than the portion serving as the external connection electrode;
The method according to claim 8, further comprising: a second step of forming the lead electrode using a vacuum process. It is a manufacturing method of the ink-jet head according to claim 5,
Forming a plurality of independent drive electrodes in each ink chamber on a channel wafer that has been polarized in the thickness direction and grooved at a predetermined pitch; and
A step of depositing and forming a wire made of the refractory metal member on a portion to be an external connection electrode;
Filling the ink chamber of the portion to be the external connection electrode with a conductive adhesive;
Curing the filled conductive adhesive;
Bonding the channel wafer and the cover wafer;
And a step of cutting the channel wafer into small pieces so as to cut the conductive adhesive filling portion and the conductive lead electrode portion.

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