JP2007076062A - Method for manufacturing inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To readily and surely achieve electrical connection between drive electrodes in a channel in the case where two piezoelectric substrates each being so constituted that a plurality of parallel grooves and the drive electrodes respectively formed in the grooves are formed on a substrate having piezoelectric elements, are bonded with each other by aligning the grooves on the substrates to form a head chip. <P>SOLUTION: In this method of manufacturing an inkjet head, two piezoelectric substrates 10 each being so constituted that the plurality of parallel grooves and the drive electrodes respectively formed in the grooves are formed on a substrate having piezoelectric elements, are bonded with each other by aligning the grooves on the substrates to form the head chip 1 on which drive walls 3 and channels 2 are alternately provided, the inkjet head ejecting ink in the channel 2 from a nozzle when a voltage is applied to the drive electrode to generate shearing deformation on the drive wall 3. After the piezoelectric substrates 10 are bonded with each other, a metallic film 4a for electrically connecting both of drive electrodes on each of the piezoelectric substrates provided in each of the channels 2 is independently formed by each channel 2 so as to bridge over a boundary line "a" between at least the two piezoelectric substrates 10 at the end face of the piezoelectric substrate 10 to which an inlet or an outlet of the channel 2 is faced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an ink jet head, and more specifically, two piezoelectric substrates each having a plurality of parallel grooves and a drive electrode formed in each groove on a substrate made of piezoelectric elements so that the grooves face each other. The present invention relates to a method of manufacturing an ink jet head in which a head chip is formed by aligning and adhering so that conduction between drive electrodes inside a channel can be easily and reliably achieved.

  Drive walls made of piezoelectric elements and channels are alternately arranged side by side, and each drive wall is shear-deformed by applying a voltage to the drive electrode formed on the wall of the drive wall facing each channel. A shear mode type inkjet head that ejects ink from nozzles creates each drive wall 100 by laminating piezoelectric elements 100a and 100b having polarization directions opposite to each other as shown by arrows in FIG. When a driving voltage is applied to the driving electrode 101 formed on the wall surface of the driving wall 100, each driving wall 100 can be greatly sheared into a dogleg shape, and a large energy for discharging the ink in the channel 102. Can be granted.

  In order to produce such an ink jet head, for example, as shown in FIG. 16, two piezoelectric elements 200a and 200b are laminated so that the polarization directions are opposite to each other, and the piezoelectric substrate 200 is formed. After driving walls 202 are juxtaposed by grinding a large number of grooves 201 serving as channels from the piezoelectric element 200a side of the 200 to the middle of the piezoelectric element 200b, drive electrodes 203 are provided inside the grooves 201. And forming a head chip by closing the top of each groove 201 with a cover substrate 204, and, as shown in FIG. 17, a large number of grooves 301 are formed in a piezoelectric substrate 300 made of a polarized piezoelectric element. After grinding in parallel, prepare two identical ones with the drive electrode 302 formed in each groove 301, and align and bond them so that the grooves 302 face each other And in, and a method of forming a head chip in which the channel 303 and the drive wall 304 is arranged alternately.

  In the former example shown in FIG. 16, the drive wall and the channel whose polarization directions are opposite to each other can be formed by grinding a piezoelectric substrate on which two piezoelectric elements are laminated using a dicing saw or the like. There is no need to position the piezoelectric elements polarized in order to form the wall, and there is an advantage that the wall surface of the drive wall can be formed as a flat surface.

  On the other hand, in the latter example shown in FIG. 17, the drive electrodes and the channels are formed by bonding the drive electrodes formed on the piezoelectric substrate on which the grooves are formed, so that the drive electrodes are formed inside the grooves of each piezoelectric substrate. In this case, since the depth of the groove is half the depth of the channel, there is an advantage that a uniform metal film can be easily formed over the entire surface of the groove.

  In the case of the inkjet head having the latter head chip shown in FIG. 17, when the piezoelectric substrates are bonded to each other, the drive electrode of one piezoelectric substrate and the drive electrode of the other piezoelectric substrate need to be connected and conductive. There is. In general, since the piezoelectric substrates are bonded to each other using an adhesive, an adhesive layer 305 exists between the piezoelectric elements 304a and 304b constituting the drive wall 304 as shown in FIG. , 302 are interfering with each other.

For this reason, conventionally, after the piezoelectric substrates are bonded to each other, a metal film 306 is further stacked on the wall surface of each drive wall 304 by evaporating a metal such as Al on the drive electrode 302. The drive electrode 302 is connected to achieve conduction (Patent Document 1).
JP-A-8-276583

  In the case where the piezoelectric substrates having the grooves are bonded to each other, the positional deviation between the upper and lower piezoelectric elements 304a and 304b is caused by a dimensional error at the time of groove processing, an alignment error at the time of bonding, and the like, as shown in FIG. And a step A may occur. In addition, since the amount of adhesive applied is too large, as shown in FIG. 19B, the adhesive layer 305 overflows and hardens inside the channel during bonding, and a protruding portion B protruding inside is generated. Sometimes.

  When such a step A or a protruding portion B occurs, even if a metal is deposited to form the metal film 306 that connects the upper and lower drive electrodes 302, the deposited metal is formed by the step A or the protruding portion B. There is a possibility that a shadow portion that does not spread is generated and the upper and lower drive electrodes 302 are not connected well.

  Further, in the case where the metal film 306 is formed by plating, there is a problem that bubbles are not easily removed due to the step A or the protruding portion B, and pinholes are easily formed in the metal film 306. If pinholes occur in the metal film 306, bubbles are likely to remain in the channel when ink is ejected, which may hinder ink ejection.

  A particular problem is that the presence or absence of such a step A and the protruding portion B and the degree thereof are not necessarily uniform in each channel. However, it is difficult to observe the inside of the channel in order to confirm the formation of the metal film 306, and even if it can be observed, the metal film 306 is formed for each channel depending on the presence or absence of the step A and the protruding portion B and the degree thereof. It is practically impossible to change the formation conditions. Further, when the metal film 306 is formed on all channels under the same formation conditions, a channel where the upper and lower drive electrodes 302 are not connected is generated due to the presence or absence of the step A or the protruding portion B and the degree thereof. There was a problem that it became a defective product and the yield deteriorated.

  In view of this, the present invention provides a piezoelectric substrate having a plurality of parallel grooves and two piezoelectric substrates each having a drive electrode formed in each groove, aligned and bonded so that the grooves face each other. When producing a head chip, it is an object to be able to easily and reliably achieve conduction between drive electrodes inside a channel.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

  According to the first aspect of the present invention, two piezoelectric substrates each having a plurality of parallel grooves and drive electrodes formed in each groove are aligned and bonded to a substrate made of piezoelectric elements so that the grooves face each other. Thus, a head chip in which drive walls and channels are alternately arranged is formed, and a voltage is applied to the drive electrodes to cause shear deformation of the drive walls so that ink in the channels is discharged from the channels. In the method of manufacturing an ink jet head that discharges from a nozzle disposed on the side, after bonding the piezoelectric substrates, a metal film for connecting a drive electrode that conducts to both of the drive electrodes of each piezoelectric substrate disposed inside each channel is formed. And forming each channel independently so as to straddle the boundary line between at least two piezoelectric substrates on the end face of the piezoelectric substrate facing the inlet and / or outlet of the channel. A method of manufacturing an ink jet head according to symptoms.

  A second aspect of the present invention is the method of manufacturing an ink jet head according to the first aspect, wherein the metal film is formed so as to surround the inlet and / or outlet of each channel.

  According to a third aspect of the present invention, in the head chip, the groove is formed from one end to the other end of each piezoelectric substrate, so that the outlet and inlet of each channel are provided on the front and rear surfaces of the head chip. At the same time as the formation of the metal film on the end face of the piezoelectric substrate facing the inlet or the outlet of the channel, the drive voltage from the drive circuit is applied to the drive electrode inside each channel by the metal film. 3. A method of manufacturing an ink jet head according to claim 1, wherein a lead electrode for applying the pressure is formed.

  According to a fourth aspect of the present invention, in the head chip, the groove is formed from one end to the other end of each piezoelectric substrate so that the outlet and inlet of each channel are provided on the front and rear surfaces of the head chip. The metal films are alternately arranged on every other channel on the front end face of the piezoelectric substrate facing the outlet of the channel and the rear end face of the piezoelectric substrate facing the inlet of the channel. 4. The method of manufacturing an ink jet head according to claim 1, wherein the ink jet head is formed.

  A fifth aspect of the present invention is the method of manufacturing an ink jet head according to any one of the first to fourth aspects, wherein the metal film is formed by a vapor deposition method or a sputtering method.

  According to a sixth aspect of the present invention, the vapor deposition method or the sputtering method is perpendicular to the end face of the piezoelectric substrate facing the inlet and / or outlet of the channel so that the metal film covers the surface of the drive electrode inside each channel. 6. The method of manufacturing an ink-jet head according to claim 5, wherein the method is performed from an oblique direction with respect to a straight line.

  According to a seventh aspect of the present invention, the vapor deposition method or the sputtering method is performed twice or more substantially symmetrically from an oblique direction with respect to a line perpendicular to the end face of the piezoelectric substrate facing the inlet and / or outlet of the channel. The method of manufacturing an ink jet head according to claim 6.

  According to the first aspect of the present invention, the conduction between the drive electrodes inside the channel can be ensured by the metal film on the end face of the piezoelectric substrate. This metal film can be formed under the same conditions for all channels on the end face of the piezoelectric substrate regardless of the level difference inside each channel and the amount of adhesive protruding, so that the drive electrodes can be connected easily. Thus, reliable conduction can be achieved.

  According to the second aspect of the present invention, since the metal film is formed so as to surround the inlet and / or outlet of each channel, the metal film and each of the drive electrodes of each piezoelectric substrate are separated by three sides. The connection state between the metal film and the drive electrode can be most ensured.

  According to the third aspect of the present invention, the formation of the lead electrode for applying the drive voltage from the drive circuit to each drive electrode in the channel and the conduction between the drive electrodes in the channel without increasing the number of steps. Can be performed simultaneously.

  According to the fourth aspect of the present invention, even when the channels have a very fine pitch, it is possible to reduce the risk that the metal films are in contact with each other between adjacent channels.

  According to the fifth aspect of the present invention, the metal film can be easily formed on the end face of the piezoelectric substrate by vapor deposition or sputtering.

  According to the sixth aspect of the present invention, it is possible to achieve reliable connection between the metal film and the drive electrode inside the channel by vapor deposition or sputtering.

  According to the seventh aspect of the present invention, a more reliable connection between the metal film and the drive electrode inside the channel can be achieved by a vapor deposition method or a sputtering method.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of one piezoelectric substrate. In the figure, reference numeral 10 denotes a piezoelectric substrate, which is composed of a relatively large piezoelectric element such as PZT that is polarized in the direction indicated by the arrow.

  A plurality of parallel grooves 11 are formed on one surface of the piezoelectric substrate 10 from one end to the other end of the piezoelectric substrate 10 by a dicing saw or the like. The number of grooves 11 is not limited to that illustrated. By the formation of the grooves 11, wall portions 12 to be drive walls later are formed between the grooves 11.

  Next, as shown in FIG. 2, drive electrodes 13 are formed in the grooves 11 of the piezoelectric substrate 10. The formation method of the drive electrode 13 may be any of vapor deposition, sputtering, plating, and the like. The drive electrode 13 is formed on the entire inner surface of each groove 11 so as not to be formed on the upper surface of the wall portion 12 between the grooves 11 in order to avoid contact between the drive electrodes 13 in the adjacent grooves 11.

  In order to selectively form the drive electrode 13 on the entire inner surface of each groove 11, for example, after a dry film or the like is pasted and masked on one surface of the piezoelectric substrate 10, the groove 11 is processed from above the mask, After the drive electrode 13 is formed, a method of removing the mask between the grooves 11 can be employed.

  In this way, two similar piezoelectric substrates 10 on which the grooves 11, the walls 12 and the drive electrodes 13 are formed are prepared. As shown in FIG. 3, the grooves 11 and 11 of the piezoelectric substrates 10 and 10 face each other. Align and bond using an adhesive. A channel 2 is formed by aligning the grooves 11 and 11 of the upper and lower piezoelectric substrates 10 and 10, and a drive wall made of a piezoelectric element whose polarization direction is opposite by aligning the walls 12 and 12. 3 is formed.

  Next, the piezoelectric substrates 10 and 10 are stacked by cutting along the parallel cut lines C, C... Extending in a direction orthogonal to the length direction of the channel 2 over the piezoelectric substrates 10 and 10. A large number of head chips 1, 1,... Are created from the body.

  The obtained head chip 1 has an outlet and an inlet of a channel 2 facing each other on the front end face (end face on the ink discharge side) and the rear end face (end face opposite to the ink discharge side). Thus, a so-called harmonica type head chip having a straight shape in which the cross-sectional shape is not substantially changed is obtained.

  The head chip 1 thus formed is electrically connected to both the drive electrodes 13 and 13 of the piezoelectric substrates 10 and 10 disposed inside each channel 2 on the end face where the entrance and / or exit of the channel 2 faces. The metal film to be formed is formed independently for each channel 2 so as to straddle the boundary line a between at least two piezoelectric substrates 10 and 10 on the end faces of the piezoelectric substrates 10 and 10 facing the inlet and / or outlet of the channel 2. .

  FIG. 4 shows an example of a method for forming this metal film. In this example, a method of selectively forming a metal film using a mask member on the rear end face facing the entrance of the channel 2 is shown.

  In the figure, F is a photosensitive dry film as a mask member attached to the end face of the head chip 1. In the photosensitive dry film F, an opening f1 independent for each channel 2 is formed at a position corresponding to each channel 2 of the head chip 1. The opening f1 is formed in a rectangular shape having an opening area slightly larger than the opening area of the entrance of the channel 2. Therefore, as shown in FIG. 4, with the photosensitive dry film F attached to the rear end face of the head chip 1 facing the inlet of the channel 2, the entire opening of the channel 2 and its surroundings are opened from the opening f1. A part of the rear end face of each of the piezoelectric substrates 10 and 10 faces so as to surround.

  Further, the harmonica type head chip 1 needs to draw out wiring for applying a driving voltage from a driving circuit (not shown) to the driving electrodes 13 and 13 in the channel 2 to the outer surface. For this reason, the photosensitive dry film F has an opening f2 for forming a lead electrode formed independently for each channel 2 in succession to each opening f1. The opening f2 extends from one side of each opening f1 in a direction orthogonal to the direction in which the channels 2 are arranged.

  With this photosensitive dry film F adhered to the rear end face of the head chip 1 facing the channel 2 inlet, a metal such as Al is deposited on the rear surface of the head chip 1 by vapor deposition or sputtering through the openings f1 and f2. Adhere to the end face. Since the metal film can be easily formed on the end face of the head chip 1, the vapor deposition method or the sputtering method can be preferably employed as the method for forming the metal film in the present invention.

  At this time, since the metal film is formed so as to cover the surfaces of the drive electrodes 13 and 13 inside each channel 2 by the attached metal particles, as shown by the arrows in FIG. It is preferable to perform vapor deposition or sputtering from an oblique direction of about 30 to 60 ° with respect to a line X perpendicular to the rear end face where the two inlets face. The metal particles irradiated from a direction oblique to the perpendicular line X adhere to the rear end face of the head chip 1 through the openings f1 and f2 of the photosensitive dry film F and enter the inside from the entrance of the channel 2. To the surface of the drive electrodes 13 and 13 inside the channel 2. Accordingly, it is possible to form a continuous metal film from the rear end surface of the head chip 1 via the inlet of each channel 2 and to reliably connect the metal film to the drive electrodes 13 and 13 in the channel 2. Can do.

  Further, this vapor deposition or sputtering is preferably performed twice or more symmetrically from the oblique direction with respect to the line X perpendicular to the rear end face where the entrance of the channel 2 faces. By performing it twice or more symmetrically from the oblique direction, the metal film can be more reliably connected to each of the drive electrodes 13 and 13 of each piezoelectric substrate 10 and 10.

  As shown in FIG. 6B, the direction to be made almost symmetrical from the oblique direction with respect to the line X perpendicular to the rear end face where the entrance of the channel 2 faces is oblique to the boundary line a between the piezoelectric substrates 10 and 10. Since the metal film formed on the rear end face of the head chip 1 so as to surround the entrance of the channel 2 can be connected to the drive electrodes 13 and 13 inside the channel 2. More preferable.

  When the photosensitive dry film F is removed after depositing metal particles having a desired thickness in the openings f1 and f2 of the photosensitive dry film F, the entrance of the channel 2 of the head chip 1 becomes as shown in FIG. A metal film 4 is selectively formed on the facing rear end face. The metal film 4 includes a drive electrode connecting metal film 4a formed so as to surround the entrance of each channel 2 by the opening f1 of the photosensitive dry film F, and a metal film integral with the metal film 4a by the opening f2. The lead electrode 4b is formed.

  The metal film 4a for connecting the drive electrodes is integrally continuous over the respective rear end surfaces of the two piezoelectric substrates 10 and 10 constituting the head chip 1, and each drive inside the channel 2 as shown in FIG. The electrodes 13 and 13 are connected to each other. Accordingly, the drive electrodes 13 in the channel 2 are made conductive by the drive electrode connecting metal film 4a.

  Therefore, there is no need to connect the drive electrodes 13 and 13 of the piezoelectric substrates 10 and 10 inside the channel 2 as in the conventional case, regardless of the step between the drive electrodes 13 and 13 and the presence or absence of the protruding portion of the adhesive. The drive electrodes 13 and 13 are surely connected only by forming the metal film 4a for connecting the drive electrodes to the rear end face (or front end face) where the inlet (or outlet) of the channel 2 of the head chip 1 faces. Can do. Further, since the metal film 4a is formed on the rear end surface (or front end surface) of the head chip 1, it is easy to check the connection state between the metal film 4a and the drive electrodes 13 and 13.

  Moreover, even if the steps generated between the drive electrodes 13 and 13 and the extent of the protruding portion of the adhesive are different in each channel 2, the drive electrodes are formed under a single formation condition for all the channels 2. Since it is only necessary to form the metal film 4a for connection, the drive electrodes 13 and 13 can be reliably connected with each other very easily, and the yield can be greatly improved. In particular, as shown in the present embodiment, if the head chip 1 is cut out from the laminate of the piezoelectric substrates 10 and 10, the end surface on which the metal film 4a is formed becomes a smooth surface. Can be formed.

  Further, since the metal film 4a can be integrally formed when the extraction electrode 4b necessary for the harmonica type head chip 1 is formed, the formation of the extraction electrode 4b and the drive electrode inside the channel 2 can be performed without increasing the number of steps. 13 and 13 can be secured simultaneously.

  Further, here, the metal film 4a for connecting the drive electrode is formed so as to surround the entrance of the channel 2, so that the metal film 4a and each of the drive electrodes 13, 13 of the piezoelectric substrates 10, 10 are As shown in FIG. 7, the sides 12 a and 12 b of both walls 12 and 12 of each piezoelectric substrate 10 and 10 that form the entrance of the channel 2 and the sides 12 c of the bottom of the groove 11 are connected by three sides. it can. For this reason, even if a connection failure between the drive electrode 13 and the metal film 4a occurs on either one or two sides, the connection can be maintained on the remaining two sides or one side. The connection state between the metal film 4a for connection and the drive electrodes 13 and 13 can be most ensured.

  As shown in FIGS. 8 and 9, the head chip 1 thus produced is bonded to the front end face with a nozzle plate 5 in which nozzles 5a are opened at positions corresponding to the respective channels 2 and the rear end face. For example, the wiring substrate 6 on which wirings 6a, 6a,... Are formed at the same positions as the extraction electrodes 4b at the same pitch as the extraction electrodes 4b is connected to the end surfaces. Thus, it can be set as the inkjet head H by adhere | attaching using an anisotropic conductive film.

  The wiring substrate 6 has the same width as the width direction of the head chip 1, extends in a direction orthogonal to the channel arrangement direction of the head chip 1, and protrudes greatly above and below the head chip 1. Each wiring 7a of the FPC 7 is aligned and bonded to the extended wiring 6a using an anisotropic conductive film or the like. In the substantially central portion of the wiring board 6, a single recess 6 b extending in the width direction is sized so as to cover the inlet side of all the channels 2 along the channel row direction of the head chip 1. Grooving. The recess 6 b can function as an ink common chamber for supplying ink to each channel 2.

  In the above embodiment, a preferable example in which the metal film 4a for connecting the drive electrode is formed integrally with the lead electrode 4b on the rear end surface of the head chip 1, but the present invention is not necessarily limited thereto. The drive electrode connecting metal film 4a may be formed on the front end face of the head chip 1 where the outlet of the channel 2 faces.

  Further, as shown in FIG. 10, the drive electrode connecting metal film 4a is formed on the front end face of the head chip 1 facing the outlet of the channel 2 and the rear end face of the head chip 1, ie, the front end face and the rear end face of the head chip 1. Alternately, every other channel 2 can be formed alternately. FIG. 10A shows the front end face of the head chip 1, and FIG. 10B shows the rear end face of the head chip 1. In this case, even if the channels 2 have an extremely fine pitch, it is possible to reduce the risk that the drive electrode connecting metal films 4a are in contact with each other between the adjacent channels 2. Note that the lead electrodes 4b are formed to have substantially the same width as the widths of the respective channels 2, so that contact between adjacent lead electrodes 4b can be prevented.

  In addition, the head chip is not limited to the type in which all channels function for ink ejection, and the head chip channel is an independent channel type in which every other channel is arranged with an ink ejection channel and an empty channel that does not eject ink. The head chip may be used.

  FIG. 11 shows an example in which a metal film 4a for driving electrode connection, an extraction electrode (individual electrode) 4b, and a common electrode 4c for an empty channel are patterned on the rear end face of the independent channel type head chip 1. In the figure, 2a is an ink ejection channel, and 2b is an empty channel.

  The common electrode 4c is formed integrally with each metal film 4a formed so as to surround the entrance of each empty channel 2b, and conducts the metal films 4a of all the empty channels 2b. As shown in the figure, it is preferable to form the common electrode 4c on the side opposite to the side on which the extraction electrode 4b is formed across the boundary line a of the piezoelectric substrates 10 and 10, because it is easy to prevent mutual contact. For example, the common electrode 4c is drawn to another end face of the head chip 1 at the end of the head chip 1 and connected to an FPC or the like.

  Also in the case of such an independent channel type head chip, as shown in FIG. 12, the metal film 4a for connecting the drive electrodes is formed by the ink discharge channel 2a and the empty channel 2b. You may form and distribute to an end surface. FIG. 12A shows the front end face of the head chip 1, and FIG. 12B shows the rear end face of the head chip 1. The metal film 4a of the all empty channel 2b and the common electrode 4c for conducting the metal films 4a are formed on the front end surface of the head chip 1, and the metal film 4a of the all ink discharge channel 2a and the metal film 4a are integrated with each other. The electrode 4 b is formed on the rear end surface of the head chip 1.

  The head chip 1 shown in FIGS. 11 and 12 is driven by vapor deposition or sputtering after a patterned mask member is attached to each end face of the head chip 1 in the same manner as shown in FIG. A metal film 4a for electrode connection, a lead electrode 4b, and a common electrode 4c can be formed.

 The metal film 4a for connecting the drive electrodes is not limited to be formed so as to surround the inlet or outlet of each channel 2, but on the end face of the piezoelectric substrate 10 where the inlet or outlet of the channel 2 faces. If each channel 2 is formed independently so as to straddle the boundary line a between at least two piezoelectric substrates 10 and 10, the drive electrodes 13 and 13 of the piezoelectric substrates 10 and 10 are connected and made conductive. be able to.

  Therefore, for example, as shown in FIG. 13, the drive electrode connecting metal film 4a may be formed only on the end face of the drive wall 3 in the head chip 1 (the rear end face is shown in FIG. 13). FIG. 13A shows an example in which a metal film 4a for connecting a drive electrode is formed on the rear end face of each drive wall 3 located on both sides of each channel 2, and FIG. An example is shown in which a drive electrode connecting metal film 4a is formed on the rear end face of the drive wall 3 located on one side.

  In the case of FIG. 13 (a), the conduction of the drive electrodes 13 and 13 of the piezoelectric substrates 10 and 10 can be ensured by the metal films 4a and 4a on both sides of each channel 2. Therefore, compared to the case of FIG. 13 (b). Reliable conduction can be performed. Moreover, in the case of FIG.13 (b), the effect which prevents the metal film 4a contact between the adjacent channels 2 is high compared with the case of Fig.13 (a).

  Also in the embodiment shown in FIG. 13, similarly to the embodiment shown in FIG. 10, when the channel 2 has an extremely fine pitch or an independent channel type head chip, the metal film 4a for connecting the drive electrodes is used. Are formed alternately with the front end face and the rear end face of the head chip every other channel 2 to prevent contact between adjacent metal films 4a more securely or to ensure complete contact between the lead electrode 4b and the common electrode 4c. It is also possible to make a proper distribution.

  The method of drawing the wiring from the drive electrode 13 of each channel 2 of the harmonica type head chip 1 is that if the lead electrode 4b is formed on the end face of the head chip 1, the metal film 4a for connecting the drive electrode and the lead electrode 4b are formed. Although there is an advantage that formation can be performed simultaneously, the present invention is not limited to this. For example, as shown in FIG. 14, a through hole 14 that penetrates from the bottom of each groove 12 of one piezoelectric substrate 10 to the outer surface of the piezoelectric substrate 10 is opened, and the through hole 14 is penetrated using a conductive paste or the like. By forming the electrode 15, the drive electrode 13 in each channel 2 can be drawn out to the outer surface of the head chip 1. In this case, the drive voltage from the drive circuit can be applied to each channel 2 by connecting the FPC to each through electrode 15.

  In the above embodiment, an example of an ink jet head having a harmonica type head chip 1 has been described. However, in the present invention, a plurality of parallel grooves and drive electrodes are formed in each groove on a substrate made of a piezoelectric element. The two piezoelectric substrates are aligned and bonded so that the grooves face each other, thereby having a head chip in which drive walls and channels are alternately arranged in parallel, and applying a voltage to the drive electrodes. As long as the drive wall is shear-deformed to discharge the ink in the channel from the nozzle disposed on the outlet side of the channel, it is not limited to one having a harmonica type head chip. For example, by grinding a groove from one end of the piezoelectric substrate to the front of the other end, the channel has a channel whose depth gradually decreases as it goes to the other end, and the direction of ink supply to each channel And an ink jet head having a so-called chopper traverse type head chip in which the ink ejection direction is substantially orthogonal to the ink ejection direction.

Perspective view of a piezoelectric substrate having a plurality of grooves formed Front view of a piezoelectric substrate with drive electrodes formed inside the groove A perspective view of a laminate in which two piezoelectric substrates are bonded together Front view showing an example of a metal film forming method Partial enlarged view of the end face of the head chip formed with a metal film (A) (b) is explanatory drawing of the formation method of a metal film Partial enlarged perspective view of the end face of the head chip on which the metal film is formed Exploded perspective view of inkjet head Cross section of inkjet head 4 shows another embodiment of a metal film for connecting drive electrodes, where (a) is a partial front view of the front end face of the head chip, and (b) is a partial front view of the rear end face of the head chip. Partial front view showing rear end face of independent channel type head chip (A) is a partial front view showing the front end face of the independent channel type head chip, (b) is a partial front view showing the rear end face of the independent channel type head chip. The other aspect of the metal film for a drive electrode connection is shown, (a) is a partial front view which shows the example which formed the metal film on both sides of each channel, (b) is the example which formed the metal film on the one side of each channel Partial front view showing Sectional drawing which shows the other aspect of a head chip Partial front view showing structure of inkjet head in shear deformation mode Explanatory drawing of an example of the manufacturing method of the inkjet head of a shear deformation mode Explanatory drawing of an example of the manufacturing method of the inkjet head of a shear deformation mode Explanatory drawing of conventional drive electrode connection method (A) is explanatory drawing of the state in which the level | step difference has generate | occur | produced in the drive wall, (b) is explanatory drawing of the state in which the protrusion part of the adhesive agent has generate | occur | produced in the driving wall.

Explanation of symbols

1: Head chip 2: Channel 2a: Ink ejection channel 2b: Empty channel 3: Drive wall 4: Metal film 4a: Metal film for connecting drive electrode 4b: Lead electrode 4c: Common electrode 5: Nozzle plate 5a: Nozzle 6 : Wiring board 6a: Wiring 6b: Recess 7: FPC
7a: Wiring 10: Piezoelectric substrate 11: Groove 12: Wall 13: Drive electrode 14: Through hole 15: Through electrode F: Photosensitive dry film f1, f2: Opening H: Inkjet head

Claims (7)

By aligning and bonding two piezoelectric substrates each having a plurality of parallel grooves and drive electrodes formed inside the grooves to a substrate made of piezoelectric elements so that the grooves face each other, the drive wall and the channel Are alternately arranged in parallel, and a voltage is applied to the drive electrode to shear the drive wall to eject ink in the channel from a nozzle disposed on the outlet side of the channel. In the method of manufacturing an inkjet head,
After bonding the piezoelectric substrates, a metal film for connecting the drive electrode that is electrically connected to both of the drive electrodes of each piezoelectric substrate disposed inside each channel is connected to the end surface of the piezoelectric substrate facing the channel inlet and / or outlet. A method for manufacturing an ink-jet head, comprising: independently forming each channel so as to straddle a boundary line between at least two piezoelectric substrates.   2. The method of manufacturing an ink jet head according to claim 1, wherein the metal film is formed so as to surround the inlet and / or outlet of each channel. The head chip is arranged so that the outlet and the inlet of each channel face the front and rear surfaces of the head chip by forming the groove from one end of the piezoelectric substrate to the other end. And
Simultaneously with the formation of the metal film, an extraction electrode for applying a drive voltage from a drive circuit to a drive electrode in each channel is formed on the end face of the piezoelectric substrate facing the channel entrance or exit. The method of manufacturing an ink jet head according to claim 1 or 2. The head chip is arranged so that the outlet and the inlet of each channel face the front and rear surfaces of the head chip by forming the groove from one end of the piezoelectric substrate to the other end. And
The metal film is alternately formed on every other channel on a front end surface of a piezoelectric substrate facing an outlet of the channel and a rear end surface of a piezoelectric substrate facing an inlet of the channel. 2. A method for producing an ink jet head according to 2 or 3.   The method of manufacturing an ink jet head according to claim 1, wherein the metal film is formed by vapor deposition or sputtering.   In the vapor deposition method or the sputtering method, a direction oblique to a line perpendicular to the end face of the piezoelectric substrate facing the entrance and / or exit of the channel so that the metal film covers the surface of the drive electrode inside each channel. The method for producing an ink jet head according to claim 5, wherein 7. The vapor deposition method or the sputtering method is performed twice or more substantially symmetrically from an oblique direction with respect to a line perpendicular to the end face of the piezoelectric substrate facing the inlet and / or outlet of the channel. Manufacturing method of the inkjet head.

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