The present invention relates to a liquid jetting apparatus and a method of producing the liquid jetting apparatus.
As a liquid jetting apparatus jetting liquid, an ink-jet head jetting ink from nozzles is known. This ink-jet head includes a head main body formed with pressure chambers and nozzles and a piezoelectric actuator applying pressure to the ink in each pressure chamber.
The pressure chambers of the head main body form four pressure chamber arrays arranged in a main scanning direction of the ink jet head. The piezoelectric actuator includes a vibration plate covering the pressure chambers, a common electrode formed on the vibration plate, a piezoelectric body disposed on the common electrode, and individual electrodes disposed on the upper surface of the piezoelectric body while corresponding to the pressure chambers. It can be said that, each individual electrode, the common electrode, and a part of the piezoelectric body sandwiched between the two kinds of electrodes are disposed to face one pressure chamber, thus forming one piezoelectric element. Namely, the piezoelectric actuator includes the piezoelectric elements that are arranged in four arrays while corresponding to the pressure chambers.
The individual electrodes of the piezoelectric elements are connected to traces. Each of the traces is led from the corresponding one of the individual electrodes to the outside in the main scanning direction. In two piezoelectric element arrays at one side, traces connected to the individual electrodes of a piezoelectric element array disposed at the inside in the main scanning direction extend to the outside while running between two piezoelectric elements of a piezoelectric element array disposed at the outside in the main scanning direction. An end of each trace is provided with a pressure input terminal.
Meanwhile, in order to prevent trace corrosion, etc., an insulating film may be provided in an area formed with the trace above a partition wall partitioning two pressure chambers. In that case, if the insulating film is disposed to partially cover, from above, the pressure chambers disposed at both sides of the trace, ends of the insulating film are positioned on the vibration plate covering the pressure chambers.
Inventors of the present application made an experimental actuator having a configuration in which the insulating film partially covers the pressure chambers from above, and then conducted a drive test. As a result, it has been revealed that the vibration plate has cracks starting at end positions of the insulating film.
An object of the present teaching is to prevent a film covering pressure chambers from having a crack which would be otherwise caused by a configuration in which an insulating film formed above a partition wall partially covers the pressure chambers from above.
According to an aspect of the present teaching, there is provided a liquid jetting apparatus including:
a first pressure chamber;
a second pressure chamber located next to the first pressure chamber in a first direction;
a first insulating film covering the first pressure chamber and the second pressure chamber;
a first piezoelectric element arranged above the first pressure chamber, the first insulating film being intervened between the first pressure chamber and the first piezoelectric element;
a second piezoelectric element arranged above the second pressure chamber, the first insulating film being intervened between the second pressure chamber and the second piezoelectric element;
a trace arranged between the first piezoelectric element and the second piezoelectric element in the first direction; and
a second insulating film covering the trace,
wherein the first pressure chamber includes a first end and a second end in the first direction, the second pressure chamber includes a third end and a fourth end in the first direction, and the second end of the first pressure chamber is located next to the third end of the second pressure chamber in the first direction,
wherein the second insulating film includes two ends between the second end of the first pressure chamber and the third end of the second pressure chamber in the first direction.
In the present teaching, the end of the part of the second insulating film coveting the at least one trace between the first piezoelectric element and the second piezoelectric element is positioned inside the end of the partition wall partitioning the first pressure chamber and the second pressure chamber. Thus, between the first piezoelectric element and the second piezoelectric element, the second insulating film does not overlap with the first pressure chamber and the second pressure chamber. In such a configuration, the end of the second insulating film is not positioned on each pressure chamber, and thus stress is less likely to concentrate on the first insulating film covering each pressure chamber. This prevents the first insulating film from having a crack.
Subsequently, an embodiment of the present teaching will be described.
<Schematic Configuration of Printer>
As depicted in
A recording sheet 100 as a recording medium is placed on an upper surface of the platen 2. The carriage 3 is configured to reciprocate in a left-right direction (hereinafter referred to as a scanning direction) in an area facing the platen 2 along two guide rails 10 and 11. An endless belt 14 is connected to the carriage 3, and a carriage drive motor 15 drives the endless belt 14 to move the carriage 3 in the scanning direction.
The ink-jet head 4, which is installed to the carriage 3, moves in the scanning direction together with the carriage 3. The ink-jet head 4 includes four head units 16 arranged in the scanning direction. The four head units 16 are connected, via unillustrated tubes, to a cartridge holder 7 to which ink cartridges 17 of four colors (black, yellow, cyan, and magenta) are installed. Each of the head units 16 includes nozzles 24 (see
The conveyance mechanism 5 includes two conveyance rollers 18 and 19 disposed to sandwich the platen 2 in a front-rear direction. The conveyance mechanism 5 conveys the recording sheet 100 placed on the platen 2 frontward (hereinafter also referred to as a conveyance direction) by use of the two conveyance rollers 18 and 19.
The controller 6 includes a Read Only Memory (ROM), a Random Access Memory (RAM), an Application Specific Integrated Circuit (ASIC) including various control circuits, and the like. The controller 6 controls the ASIC to execute a variety of processing, such as printing for the recording sheet 100, in accordance with programs stored in the RUM. For example, in the print processing, the controller 6 controls the ink-jet head 4, the carriage drive motor 15, and the like to perform printing of an image or the like on the recording sheet 100 based on a printing command input from an external apparatus, such as a PC. In particular, the controller 6 alternately performs an ink jetting operation in which the ink-jet head 4 jets ink while moving in the scanning direction together with the carriage 3 and a conveyance operation in which conveyance rollers 18 and 19 convey the recording sheet 100 in the conveyance direction by a predefined amount.
<Details of Ink-Jet Head>
Subsequently, a configuration of the ink-jet head 4 will be explained in detail. Since the four head units 16 of the ink-jet head 4 have the same configuration, one of the head units 16 will be explained and the remaining head units 16 are omitted from the explanation.
As depicted in
<Nozzle Plate>
The nozzle plate 20 is made from a metal material, such as stainless steel, or a synthetic resin material, such as silicon or polyimide. The nozzle plate 20 includes nozzles 24. As depicted in
<Channel Substrate>
The channel substrate 21 is made from silicon. The nozzle plate 20 is joined to a lower surface of the channel substrate 21. The channel substrate 21 includes pressure chambers 26 communicating with the nozzles 24, respectively. Each of the pressure chambers 26 has a rectangular planar shape elongated in the scanning direction. The pressure chambers 26 are arrayed in the conveyance direction while corresponding to the array of the nozzles 24 described above, thus forming two pressure chamber arrays 27 (27a and 27b) arranged in the left-right direction.
<Piezoelectric Actuator>
The piezoelectric actuator 22 applies, to the ink in each pressure chamber 26, jetting energy for jetting the ink from each nozzle 24. The piezoelectric actuator 22 is disposed on an upper surface of the channel substrate 21.
As depicted in
As depicted in
The vibration film 30 is disposed on an entire area of the upper surface of the channel substrate 21 to cover the pressure chambers 26. The vibration film 30 is made from silicon dioxide (SiO2), silicon nitride (SiNx), or the like. The thickness of the vibration film 30 is, for example, approximately 1 μm.
The piezoelectric elements 40 are disposed to face the pressure chambers 26 with the vibration film 30 being intervened therebetween. Namely, the piezoelectric elements 40, which are arrayed in the conveyance direction while corresponding to the array of the pressure chambers 26, form two piezoelectric element arrays 41 arranged in the scanning direction. Each of the piezoelectric elements 40 includes a lower electrode 31, the piezoelectric film 32, and an upper electrode 33,
The lower electrode 31 is formed on an upper surface of the vibration film 30 to face the pressure chamber 26. As depicted in
Each piezoelectric film 32 is formed on the upper surface of the vibration film 30 via the lower electrode 31 in an area facing the pressure chamber 26. As depicted in
Each upper electrode 33 has a rectangular planar shape that is slightly smaller than the piezoelectric film 32. The upper electrode 33 is formed on a central portion of an upper surface of the piezoelectric film 32. The upper electrode 33 is made from, for example, iridium (Ir). The thickness of the upper electrode 33 is, for example, approximately 80 nm.
As depicted in
In order not to make the protective film 34 obstruct deformation of the piezoelectric films 32, the protective film 34 includes rectangular openings 34a at parts overlapping with the central portions of the upper surfaces of the piezoelectric films 32 as viewed in a thickness direction of the protective film 34. Thus, a large part of each upper electrode 33 is exposed from the protective film 34. In an inside area of each opening 34a, the piezoelectric film 32 is not covered with the protective film 34, but covered with the upper electrode 33. Thus, moisture is prevented from coming into each piezoelectric film 32 from the outside.
As depicted in
Each of the traces 35, which will be described next, is disposed on the insulating film 36. The insulating film 36 is provided primarily for improving the insulation quality between the conductive film 38 of the common electrode 39 and each trace 35. Without being limited to any particular material, the insulating film 36 is made from, for example, silicon dioxide (SiO2). Further, from the point of view of securing the insulation quality between the common electrode 39 and each trace 35, the insulating film 36 preferably has a certain film thickness, such as from 300 to 500 nm.
Each of the traces, which is disposed on the insulating film 36, applies voltage to the corresponding one of the piezoelectric elements 40. The trace 35 is arranged with its one end hanging over an upper surface of a right end of the piezoelectric film 32 across the protective film 34 and insulating film 36. Further, a conducting portion 55 is provided at parts, of the protective film 34 and the insulating film 36, covering a right end of the upper electrode 33 to penetrate through those films. The conducting portion 55 enables electrical conduction between the trace 35 and the right end of the upper electrode 33. The traces 35 corresponding to the piezoelectric elements 40 extend rightward respectively from the corresponding upper electrodes 33. The traces 35 are made from, for example, aluminum (Al).
The traces 35, which are led from the left-side piezoelectric element array 41a of the two piezoelectric element arrays 41 arranged in the left-right direction, are disposed on the insulating film 36 to run between piezoelectric elements 40 forming the right-side piezoelectric element array 41b. Namely, the traces 35 connected to the left-side piezoelectric elements 40 extend rightward at a position above the partition wall 28 to run between two piezoelectric elements 40 forming the right-side piezoelectric element array. In order to prevent trace breaking and the like as much as possible, each of the traces 35 preferably has a certain thickness or more, such as approximately 1 μm.
The insulating film 36, which is disposed under each trace 35, extends up to a right end of the channel substrate 21. As depicted in
The trace protective film 37 is formed on the insulating film 36 to cover each trace 35. The trace protective film 37 is provided for main purposes of protecting the trace 35 and securing the insulation between the traces 35. The trace protective film 37 is made from, for example, silicon nitride (SiN). The thickness of the trace protective film 37 is, for example, from 100 nm to 1 μm.
As depicted in
As depicted in
An explanation will be made about a formation range of the insulating film 36 and the trace protective film 37 around each piezoelectric element 40 in detail.
At first, a formation range of the films 36, 37 in the conveyance direction, i.e., a lateral direction of the pressure chamber 26 will be described. As depicted in
Between the two piezoelectric elements 40, both ends of the trace protective film 37 and the insulating film 36 in the conveyance direction are positioned inside ends of the partition wall 28. Namely, the trace protective film 37 and the insulating film 36 disposed above the partition wall 28 do not extend to areas facing the pressure chambers 26 partitioned by the partition wall 28. In that configuration, the ends of the insulating film 36 and the trace protective film 37 in the conveyance direction are not positioned above the pressure chambers 26. Thus, in a case of driving each piezoelectric element 40, the vibration film 30 covering each pressure chamber 26 is prevented from having cracks starting at the ends of the trace protective film 37 and the insulating film 36. As depicted in
Although the details will be described later, etching for the trace protective film 37 and etching for the insulating film 36 are performed through the same step. Thus, the positions of the openings 37a of the wiring protective film 37 are coincident with the positions of the openings 36a of the insulating film 36. This allows the ends of the trace protective film 37 and the ends of the insulting film 36 to be positioned at the same positions above the partition wall 28 in the conveyance direction. Actually, although end positions of the trace protective film 37 slightly deviate from those of the insulating film 36 depending on taper shapes of film ends that are formed at the time of etching, the above-described configuration in which the ends of the trace protective film 37 and the ends of the insulting film 36 are positioned at the same positions includes a case in which such a slight deviation is present.
Subsequently, a formation range of the films 36, 37 in the scanning direction, i.e., a longitudinal direction of the pressure chamber 26 will be described with reference to
When the trace protective film 37 and the insulating film 36 partially overlap with each pressure chamber 26 in the longitudinal direction and they do not extend over or cover each piezoelectric film 32, the vibration film 30 is more likely to have cracks starting at the ends of the films 36 and 37, like the case in which the films 36 and 37 extend beyond each pressure chamber 26 in the lateral direction of the pressure chamber 26. In the present teaching, the ends of the trace protective film 37 and the insulating film 36 extend over or cover the upper surface of each piezoelectric film 32, thus preventing cracks starting at the ends of the films 36, 37.
When the insulating film 36 and the trace protective film 37 partially overlap with each pressure chamber 26 and each piezoelectric film 32, the vibration film 30 may be prevented from being displaced in a case of driving the piezoelectric element 40. This problem, however, is more likely to be caused in film parts in the lateral direction of the pressure chamber 26 that has great influence on the displacement, and the problem is less likely to be caused in the film ends in the longitudinal direction that has small influence on the displacement. Thus, although the degree of displacement is slightly reduced, the present embodiment adopts a configuration in which the trace protective film 37 and the insulating film 36 partially overlap with each piezoelectric chamber 26 and each piezoelectric film 32 in the longitudinal direction of the pressure chamber 26 to reliably prevent the vibration film 30 from having a crack.
As depicted in
Based on a control signal sent in from the controller 6, the driver IC 51 generates and outputs a drive signal for driving the piezoelectric actuator 22. The drive signal output from the driver IC 51 is input to the drive contact portions 42 via the traces 55a of the COF 50 and supplied to the respective upper electrodes 33 via the traces 35 of the piezoelectric actuator 22. The upper electrodes 33 supplied with the drive signal change in potential between a predefined drive potential and a ground potential. Further, the COF 50 is formed with a ground trace (not depicted), and the ground trace is electrically connected to the ground contact portions 43 of the piezoelectric actuator 22. This allows the common electrode 31 connected to the ground contact portions 43 to be constantly kept at the ground potential.
The following explanation will be made on an operation of the piezoelectric actuator 22 when supplied with the drive signal from the driver IC 51. Without being supplied with the drive signal, the upper electrodes 33 stay at the ground potential and thus have the same potential as the common electrode 39. From this state, if the drive signal is supplied to any of the upper electrodes 33 to apply the drive potential to that upper electrode 33, then due to the potential difference between that upper electrode 33 and the common electrode 39, the piezoelectric film 32 is acted on by an electric field parallel to its thickness direction. On that occasion, piezoelectric reverse effect makes the piezoelectric film 32 to extend in its thickness direction and to contract in its planar direction. Further, along with the contraction deformation of the piezoelectric film 32, the vibration film 30 bows to project toward the pressure chamber 26. By virtue of this, the pressure chamber 26 decreases in volume to produce a pressure wave inside the pressure chamber 26, thereby jetting liquid drops of the ink from the nozzle 24 in communication with the pressure chamber 26.
<Reservoir Formation Member>
As depicted in
The reservoir formation member 23 has an upper half portion formed with a reservoir 52 extending in the conveyance direction. Through non-depicted tubes, the reservoir 52 is connected to the cartridge holder 7 (see
As depicted in
Next, referring to
First, as depicted in
Further, the upper electrodes 33 are formed on the upper surface of the piezoelectric material film 59. First, as depicted in
As depicted in
Next, as depicted in
After forming the protective film 34 and the insulating film 36, as depicted in
Subsequently, the traces 35 are formed on the insulating film 36 upon the protective film 34. First, as depicted in
Next, as depicted in
Next, as depicted in
Specifically, removal of the trace protective film 37 and the insulating film 36 is performed as follows. At first, a mask covering areas other than the formation areas of the openings 36a, 37a is formed on a surface of the trace protective film 37 through photoresist. After forming the mask, etching is performed from the surface of the trace protective film 37 to remove the trace protective film 37 and the insulating film 36 at a time. Then, the openings 36a, 37a are formed in areas, of the two kinds of films 36 and 37, which are not covered with the mask. After the etching, the mask is released and removed.
As depicted in
In particular, the removal step is performed by setting a target formation position P0 for an end of the insulating film 36 and the trace protective film 37 in the conveyance direction at the inside of a target formation position P1 for an end of the partition wall 28. Here, “the target formation position of an end of the films 36, 37” means a target position of an end of the films 36, 37 in a case of etching them, and thus a mask position, an etching amount, and the like are adjusted to position the end of the films 36, 37 in the target position. Similarly, “the target formation position of an end of the partition wall 28” means a target position of an end of the partition wall 28 when the channel substrate 21 is etched to form the pressure chamber 26 in a step of forming the pressure chamber 26 as described later (
Here, various kinds of deviations caused during etching for the films 36,37 may cause deviations of the ends of the films 36, 37 from the target formation positions P0 as depicted by two-dot chain lines in
The inventors of the present application manufactured a head unit in such a setting in which the ends of the films 36, 37 are coincident with the ends of the partition wall 28, and they conducted a drive test. The vibration film 30 cracked during the test. The investigation revealed that, due to deviations during etching, the ends of the films 36, 37 extend beyond the ends of the partition wall 28 and the films 36, 37 partially overlapped with the pressure chambers 26. The thickness of the vibration film 30 of this trial product is from 1.0 to 1.4 μm.
In view of the above, the target formation position P0 for the end of the films 36, 37 is preferably positioned inside the target formation position P1 for the end of the partition wall 28 by not less than 3 μm. The reason thereof is as follows.
In the step of removing the insulating film 36 and the trace protective film 37, a mask deviation causes a position (a) of the films disposed above the partition wall 28 to vary, and a processing deviation during etching causes a film width (b) to vary. Those variations may cause positions of ends of the films 36, 37 to deviate. In the step of forming the pressure chamber 26 (
Although degrees of various deviations described above depend on the precision of an apparatus to be used for etching the films 36, 37 and forming the pressure chamber 26, they may have values indicated in Table 1. The values in Table 1 indicate values for 30σ, and the probability that deviations are within that range is 99.7%. in Table 1, “mask deviation” means the degree of a position deviation caused when an etching mask deviates in parallel with respect to a planer direction; “processing deviation” means the degree of a width deviation caused by etching processing. For example, “mask deviation in pressure chamber formation is +3 μm” means that the etching mask deviates from a target setting position by a maximum of 3 μm when the channel substrate 21 is etched to form the pressure chamber 26.
As described above, removing the insulating film 36 and the trace protective film 37 at a time reduces the number of removal steps. This means that opportunities causing the mask deviation and processing deviation are reduced. On the other hand, when removal of the two kinds of films 36, 37 are performed individually, two removal steps are required. Thus, the mask deviation and processing deviation may be caused in respective two removal steps, increasing the total deviation amount.
On the basis of the degrees of deviations indicated in Table 1, investigation will be made about a proper manner of setting for the target formation position P0.
(1) In a certain manner, we focus attention on a mask deviation (a maximum of 3 μm) in pressure chamber formation having the maximum deviation amount among kinds of deviations indicated in Table 1. Namely, the target formation position P0 is set so that the end position of the films 36, 37 is prevented from being positioned outside the partition wall 28 even in occurrence of the mask deviation having the maximum deviation amount. According to this manner, it is only required that the target formation position P0 for the end of the film 36, 37 be set at the inside of the target formation position P1 for the end of the partition wall 28 by not less than 3 μm.
(2) In another manner, the target formation position P0 may be set so that the end position of the films 36, 37 do not extend beyond the end of the partition wall 28 even in occurrence of all kinds of deviations indicated in Table 1. In that configuration, the target formation position P0 may be set on the basis of a sum of maximum values of all kinds of deviations, that is, a value obtained by summing the respective worst values. However, the probability that all kinds of deviations have respective maximum deviation amounts is almost zero, and thus setting for satisfying such a condition is unrealistic.
Thus, the target formation position P0 is preferably determined based on “square sum of common difference (square sum of tolerance)”. As a precondition, four kinds of sizes (a to d) indicated in Table 1 do not interfere with each other. Namely, a to d are independent subjects. In that case, on the assumption that the variation of the distance T follows a normal distribution, a distribution T2 of the distance T is represented by the following formula in accordance with distribution additivity.
The processing deviations (b), (d) indicated in Table 1 mean width deviation values including the film width and partition wall width. Thus, when a deviation amount of an end position is determined, a half value of the width deviation value is used for the width deviation, as indicated in Formula 1. The following formula is obtained by modifying Formula 1 in a form of a standard deviation.
When respective deviation values indicated in Table 1 are substituted for a to d, T is 3.17. Since the a to d values are values for 3σ is not more than 3.17 μm with 99.7% probability. In a practical way, when the target formation position P0 of the end of the films 36, 37 is set inside the target formation position P1 of the end of the partition wall 28 by not less than 3 μm, the films 36, 37 do not extend beyond the ends of the partition wall 28.
The target formation position P0 of the end of the films 36, 37 disposed above the partition wall 28 may be expressed by a relation with the dimension of the partition wall 28. When the nozzles 24 and the pressure chambers 26 are arrayed at 300 dpi, the array pitch of the pressure chambers 26 is 84.7 μm (size A in
The relation between the width of the films 36, 37 and the width of the partition wall 28 after performing the removal step of the films 36, 37 is as follows. When the target formation position P0 of the end of the films 36, 37 is set at the position having 3 μm distance from the end of the partition wall 28, the width W of the films 36, 37 depicted in
W≤W1−(3 μm×2)+(0.2 μm)+(2 μm)=W1−3.8 μm
The step of removing the trace protective film 37 and the insulating film 36 is completed in the step of 10A. Next, as depicted in
As depicted in
After the polish step, as depicted in
In the above embodiment, the conveyance direction and the lateral direction of the pressure chamber 26 correspond to “first direction” of the present teaching, and the scanning direction and the longitudinal direction of the pressure chamber 26 correspond to “second direction” of the present teaching. Two pressure chambers 26 of the right-side pressure chamber array 27b correspond to “first pressure chamber” and “second pressure chamber” of the present teaching. The vibration film 30 corresponds to “first insulating film” of the present teaching. Two piezoelectric elements 40 of the right-side piezoelectric element array 41b correspond to “first piezoelectric element” and “second piezoelectric element” of the present teaching. The trace protective film 37 corresponds to “second insulating film” of the present teaching. The insulating film between layers 36 corresponds to “third protective film” of the present teaching.
The step of forming the trace protective film 37 depicted in
Subsequently, an explanation will be made about modified embodiments in which various modifications are added to the above embodiment. The components or parts, which are the same as or equivalent to those of the embodiment described above, are designated by the same reference numerals, any explanation therefor will be omitted as appropriate.
In the embodiment, the common electrode 39 including the lower electrodes 31 and the conductive films 38 is formed on the almost entire area of the upper surface of the vibration film 30. Each of the conductive films 38 is disposed on the corresponding one of the partition walls 28 (see
At positions of the common electrode 39 formed with the openings 39a, however, no metallic film having ductility and malleability is present on the surface of the vibration film 30, thus those positions are vulnerable to a crack. In order to solve that problem, the ends of the insulating film 36 and the trace protective film 37 are preferably positioned inside the ends of the partition wall 28 for the purpose of preventing the vibration film 30 from having a crack.
In the above embodiment, the pressure chambers 26 form two pressure chamber arrays 27, and the piezoelectric elements 40 are also arranged in two arrays corresponding to the arrangement of the pressure chambers 26. The number of arrays of the pressure chambers 26 and the piezoelectric elements 40, however, is not limited to two arrays.
For example, as depicted in
As depicted in
When the number of traces 35 arranged between the piezoelectric elements 40 is different between the four piezoelectric element arrays 41, the width of the insulating film 36 and the trace protective film 37 may depend on the number of traces 35. However, when the width of the insulating film 36 and the trace protective film 37 disposed above the partition wall 28 is different between the four piezoelectric element arrays 41, the distance between the end of the films 36, 37 and the end of the partition wall 28, namely, the distance to the end of the pressure chamber 26 is different between the four piezoelectric element arrays 41 This causes displacement of the vibration film 30 to vary between the piezoelectric elements 40, thus leading to unevenness of jetting characteristics between the nozzles 24.
Thus, regardless of the number of traces 35 arranged between the piezoelectric elements 40, the four piezoelectric element arrays 41 are preferably configured such that parts of the films 36 and 37 covering the traces 35 are identical in width. Namely, in the removal step for the films 36 and 37, the target formation position P0 of the end of the films 36, 37 is set to be common between the four piezoelectric element arrays 41. This allows the four piezoelectric element arrays 41 to have almost the same distance from the end of the partition wall 28 to the end of the films 36 and 37, thus uniformizing jetting characteristics.
In the embodiment depicted in
In the above embodiment, the insulating film 36 and the trace protective film 37 are removed through etching at a time, the insulating film 36 and the trace protective film 37, however, may be removed through different steps. In that case, the step of removing the trace protective film 37 corresponds to “first removal step” of the present teaching, and the step of removing the insulating film 36 corresponds to “second removal step” of the present teaching.
In the above embodiment, each trace 35 covered with the trace protective film 37 is a trace for applying driving potential to the piezoelectric element 40. The trace 35, however, is not limited to such a trace. For example, each trace 35 may be a ground trace connected to the common electrode.
In the above embodiment, the lower electrodes that are conducted to each other between the piezoelectric elements form the common electrode, and the upper electrodes are individual electrodes provided separately for each of the piezoelectric elements. The present teaching, however, is not limited thereto. The lower electrodes may be individual electrodes, and the upper electrodes may form the common electrode.
The piezoelectric actuator 22 of the above embodiment includes two kinds of film s: the insulating film 36 and the trace protective film 37. The present teaching, however, is not limited thereto. The piezoelectric actuator 22 may include any one of the insulating film 36 and the trace protective film 37.
For example, like the above embodiment depicted in
When the traces 35 are made from aluminum, the trace protective film 37 covering the traces 35 is preferably provided to prevent corrosion and the like. When the traces 35 are made from any stable material such as gold, the trace protective film 37 may not be formed.
In the above embodiment and modified embodiments, the present teaching is applied to the ink-jet head that discharges ink on the recording sheet to print an image or the like thereon. The present teaching, however, may be applied to a liquid discharge apparatus that is used in various ways of use other than the print of the image or the like. The present teaching can be also applied, for example, to a liquid discharge apparatus that discharges a conductive liquid onto a substrate to form a conductive pattern on a surface of the substrate.
Number | Date | Country | Kind |
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2016-015191 | Jan 2016 | JP | national |
This application is a continuation of U.S. patent application Ser. No. 16/180,551 filed on Nov. 5, 2018, which is a divisional application of U.S. patent application Ser. No. 15/41.6,668 filed on Jan. 26, 2017, now U.S. Pat. No. 10,155,380, and claims priority from Japanese Patent Application No. 2016-015191 filed on Jan. 29, 2016, the disclosures of each of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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Parent | 15416668 | Jan 2017 | US |
Child | 16180551 | US |
Number | Date | Country | |
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Parent | 16180551 | Nov 2018 | US |
Child | 16528745 | US |