JP2010284908A - Inkjet head and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the excess or deficiency of an amount of an adhesive from occurring irrespective of the processing accuracy of a member or an individual difference in warpage caused by heating for curing the adhesive, and to provide an inkjet head having ink chambers each of which hardly causes clogging. <P>SOLUTION: On a piezoelectric material substrate 1, there are formed a plurality of partition walls arranged roughly in parallel at intervals in one direction, a plurality of ink grooves 2 formed between the adjacent partition walls and having opened both ends, and an adhesive absorption groove 5 which is placed outside the plurality of ink grooves 2 and has one opened end. Furthermore, there are formed a nozzle plate which is placed so as to cover the plurality of ink grooves 2 and has a plurality of nozzle holes communicating with the plurality of ink grooves 2, a first common ink chamber communicating with openings of one-side ends of the plurality of ink grooves 2 and communicating with the opening of the one end of the adhesive absorption groove 5, and a second common ink chamber communicating with openings of other ends of the plurality of ink grooves 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inkjet head, for example, an inkjet head suitable for use in a printer or the like. The present invention also relates to a method for manufacturing an inkjet head.

  In recent years, in printers, non-impact printing apparatuses such as an ink jet system that can easily cope with colorization and multi-gradation are rapidly spreading instead of impact printing apparatuses. As an ink jet head as an ink ejecting apparatus used for this, a drop-on-demand type in which only ink droplets necessary for printing are ejected is attracting attention because of its excellent ejection efficiency and ease of cost reduction. Yes.

  Here, as the drop-on-demand type, a Kaiser method or a thermal jet method is mainly used.

  However, the Kaiser method has a drawback that it is difficult to reduce the size and is not suitable for high density. Although the thermal jet method is suitable for increasing the density, the ink is heated with a heater to generate bubbles in the ink and ejected using the energy of the bubbles. The heat resistance of the ink is required, and it is difficult to extend the life of the heater. Moreover, since energy efficiency is bad, power consumption also becomes large.

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

  In recent years, inkjet heads using this shear mode deformation have been actively used for industrial purposes. For example, wiring is drawn by ejecting a conductive member as ink, a color filter is produced by ejecting inks of R, G, and B colors, or thermosetting or ultraviolet (UV) curable ink. The three-dimensional structure such as a microlens or a spacer is manufactured or discharged.

  There are a wide variety of inks used in this way. For example, highly volatile inks containing organic solvents, strongly acidic / strongly alkaline inks, inks containing pigments and resin components, and fine particles such as beads. There are inks to be contained, and inks in which these are combined.

  Here, in ink containing fine particles such as beads, the fine particles may settle or float due to the specific gravity difference between the ink solvent and the contained fine particles, and uneven distribution of the fine particle concentration in the ink may occur. Here, when the distribution is biased, the number of fine particles contained in the droplets at the time of ejection varies, resulting in deterioration of product performance and occurrence of defects. Furthermore, the nozzle hole may be clogged.

  In order to avoid such a situation, it is necessary to prevent the precipitation of fine particles by circulating and stirring the ink in the inkjet head. More precisely, in order to stably discharge the number of fine particles contained in the droplets at the time of discharge, the above-described ink circulation and stirring may be performed at a time when the ink is in the immediate vicinity of the nozzle hole. is important.

  As a technique for circulating and stirring the ink up to the vicinity of the nozzle hole, there is one described in International Publication WO95 / 31335 (Patent Document 1). In the ink jet head shown in FIGS. 2 and 3 of Patent Document 1, the pressure generation chamber is defined by a nozzle plate having nozzle holes on the front side and a diaphragm on the rear side. Two common ink chambers are arranged on both sides of the pressure generation chamber so as to sandwich the pressure generation chamber, and the two common ink chambers communicate with the pressure generation chamber. This apparatus supplies ink from one common ink chamber to the other common ink chamber via a pressure generating chamber. In this ink jet head, the pressure generation chamber itself with the nozzle holes serves as a path for the ink, so that the ink can be circulated to the immediate vicinity of the nozzle holes. FIG. 4 of Patent Document 1 shows the entire recording apparatus including the ink jet head. In this recording apparatus, ink can be replenished from the ink cartridge to the sub tank via the ink jet head, and ink can be returned from the sub tank to the ink cartridge via the ink jet head using the water head difference. Yes. In the recording apparatus of Patent Document 1, the ink is circulated in this way.

  Japanese Unexamined Patent Application Publication No. 2009-34884 (Patent Document 2) discloses an ink jet head having an ink chamber communicating with a plurality of common ink chambers and utilizing shear mode deformation of a piezoelectric material.

  Ink jet heads are of a stacked type. This is to assemble the structure of the ink jet head by overlapping each member while aligning them, and an example thereof is described in JP-A-6-183029 (Patent Document 3).

International Publication WO95 / 31335 JP 2009-34884 A JP-A-6-183029

  In the recording apparatus described in Patent Document 1, when ink is exchanged between the ink cartridge and the sub tank, the pressure generation chamber is moved from one common ink chamber to the other common ink chamber in the course of the circulation. However, there is a drawback that the ink-jet head is a multilayer ink-jet head.

  As described in Patent Document 3, the multilayer inkjet head includes a vibrator unit in which a vibrator is attached to a base, a flow path component member, a diaphragm forming member, a pressure generation chamber, It is composed of five members, a spacer for forming a gap to be formed, and a nozzle plate having nozzle holes, and each is assembled by aligning and overlapping. In an inkjet head, in order to achieve landing accuracy and ejection performance with little variation, the relative positional accuracy of the nozzle hole and the drive unit is extremely important, and the center of the nozzle hole and the center of the ink path in the drive unit are Must match. Therefore, the above five members are required to be aligned with high accuracy. In addition, in order to produce one ink jet head, it is necessary to repeat such highly accurate alignment four times. This is a very complicated and labor-intensive operation. In addition, the inkjet head of Patent Document 3 is not suitable for miniaturization because it uses a laminated piezoelectric element to secure the amount of displacement, and the number of components constituting the inkjet head itself is large. Furthermore, due to the complexity of the assembly work and the large number of parts, it is difficult to reduce the cost of the inkjet head.

  On the other hand, as an example of the non-stacked inkjet head, there is a share mode inkjet head described in Patent Document 2. This ink jet head includes a piezoelectric substrate, a manifold member, and a nozzle plate. A plurality of channel grooves are formed in parallel on the piezoelectric substrate. By covering this with a nozzle plate in which a plurality of nozzle holes are formed, a plurality of ink chambers are formed. The manifold member has a recess. By combining the piezoelectric substrate and the nozzle plate, a common ink chamber is formed at both ends of each of the plurality of ink chambers. This ink-jet head has a small number of constituent members and requires highly accurate positioning during assembly. The piezoelectric substrate formed in the channel groove and the nozzle plate in which the nozzle holes are formed are bonded together. There is an advantage that it is only a process. In addition, there is an advantage that the assembly process is easy and suitable for miniaturization.

  In the ink jet head described in Patent Document 2, each ink chamber and common ink chamber serving as an ink flow path are formed by bonding a piezoelectric substrate, a manifold member, and a nozzle plate using an adhesive. Here, if the amount of the adhesive is small, the possibility of leakage increases, and if the amount is large, excess adhesive protrudes into each ink chamber or common ink chamber. In particular, since each ink chamber is very long and narrow, it is easily filled with an adhesive so that ink cannot be ejected. The ink chambers are not necessarily filled with the adhesive when the piezoelectric substrate and the nozzle plate are bonded. In bonding the piezoelectric substrate and the manifold member, or bonding between the manifold members, the excessive adhesive may have a corner formed by the piezoelectric substrate and the nozzle plate, or a corner formed by the piezoelectric substrate and the manifold. It also occurs when it travels. For this reason, it is desirable that the amount of the adhesive is not excessive or insufficient in bonding any member.

  However, because there are individual differences in the processing accuracy of each member and the degree of warping due to heating for curing the adhesive, the volume of the gap filled with the adhesive is not constant, and the same amount of adhesive is applied. However, excess and deficiency may occur. Further, in the adhesion between the nozzle plate and another member, since the nozzle plate is a thin resin film and can be easily deformed, it is easy to follow the shape of the mating member, and the amount of the adhesive is less likely to occur. On the other hand, in bonding the piezoelectric substrate and the manifold member, or bonding between the manifold members, any member does not follow the shape of the mating member, so that the amount of the adhesive tends to be excessive or insufficient. As described above, since the amount of the adhesive tends to be excessive or insufficient, it is difficult to produce an inkjet head with a high yield.

  Accordingly, an object of the present invention is to provide an inkjet that is less likely to cause excess or deficiency in the amount of adhesive and clogging of each ink chamber, regardless of the processing accuracy of the members and individual differences in warpage due to heating for curing the adhesive. To provide a head.

  Moreover, the subject of this invention is providing the manufacturing method of such an inkjet head.

In order to solve the above problems, the inkjet head of the present invention is
A plurality of partition walls arranged substantially parallel to each other in one direction, a plurality of ink grooves formed between adjacent partition walls, and open at both ends, and positioned outside the plurality of ink grooves. And a piezoelectric substrate having an adhesive absorbing groove that opens only at one end;
A nozzle plate arranged to cover the plurality of ink grooves and having a plurality of nozzle holes communicating with the ink grooves;
A first common ink chamber communicating with the opening on one end side of the plurality of ink grooves and communicating with the opening on the one end side of the adhesive absorbing groove;
And a second common ink chamber communicating with the opening on the other end side of the plurality of ink grooves.

  According to the ink jet head of the present invention, since the adhesive absorbing groove is provided outside the plurality of ink grooves of the piezoelectric substrate, the piezoelectric substrate and the manifold member are bonded to form the common ink chamber. In addition, even when the manifold members are bonded to each other, even if the excess adhesive travels along the corner formed by the piezoelectric substrate and the nozzle plate, the excess adhesive can be absorbed into the adhesive absorption groove. The excess adhesive does not reach each ink chamber. Therefore, even if the amount of the adhesive is set to be large, the clogging of the adhesive in each ink chamber can be prevented, so that the range of the amount of the adhesive without excess or deficiency can be widened.

  In addition, since the adhesive absorption groove is open only at one end and communicates only with the first common ink chamber, the adhesive absorption groove is formed in both the first common ink chamber and the second common ink chamber. Compared to the case of communication, the adhesive absorbed from the second common ink side is not affected at all, and a fixed amount of adhesive can always be absorbed from the first common ink side. It is also possible to prevent the adhesive absorbed from one side from flowing out from the other opening side.

In one embodiment,
In the adhesive absorbing groove, the depth of the adhesive absorbing groove becomes shallower from the opening side of the adhesive absorbing groove toward the back side.

  If bubbles remain in the adhesive absorption groove, the remaining air expands when heated to use an adhesive that requires heat curing, and the adhesive discharged from the adhesive absorption groove The agent may flow into the ink groove.

  According to the above embodiment, the adhesive absorption groove has a cross-sectional area that decreases from the opening toward the back, so that the adhesive that has flowed into the adhesive absorption chamber can be sequentially filled from the back by capillary action. It is possible to suppress the generation of bubbles in the adhesive absorption chamber. Therefore, it is possible to stably absorb excess adhesive.

In one embodiment,
The adhesive absorption groove has a narrower width as it goes from the opening side to the back side of the adhesive absorption groove.

  Even if the width is narrowed from the opening to the back instead of changing the depth of the groove, the same effect as that obtained by changing the depth of the groove can be obtained.

  According to the above embodiment, the adhesive absorption groove has a cross-sectional area that decreases from the opening toward the back, so that the adhesive that has flowed into the adhesive absorption chamber can be sequentially filled from the back by capillary action. It is possible to suppress the generation of bubbles in the adhesive absorption chamber. Therefore, it is possible to stably absorb excess adhesive.

In one embodiment,
The opening depth of the adhesive absorbing groove is deeper than the opening depth of the ink groove.

  According to the embodiment, since the depth of the opening of the adhesive absorbing groove is deeper than the depth of the opening of the ink groove, excess adhesive is formed at the corners formed by the piezoelectric substrate and the manifold, etc. Even if it travels deeper than the opening depth of the ink groove, the excess adhesive can be absorbed by the adhesive absorption groove, and the excess adhesive does not reach the ink groove. Therefore, ink groove clogging due to the adhesive can be more effectively prevented.

In addition, the method for manufacturing the inkjet head of the present invention includes:
An inkjet head manufacturing method for manufacturing the inkjet head of the present invention, comprising:
The step of forming the ink groove having both ends opened on the piezoelectric substrate and the step of forming the adhesive absorbing groove having only one end opened on the piezoelectric substrate are performed in succession.

  According to the present invention, since the ink groove that opens at both ends of the piezoelectric substrate and the groove that opens at one end of the piezoelectric substrate are continuously formed, it is possible to save the trouble of resetting the piezoelectric substrate on the processing stage, The time required for manufacturing the inkjet head can be reduced. Further, since each ink groove and the adhesive absorption groove are formed without re-installing the piezoelectric substrate on the processing stage, the positional accuracy of each ink groove and the adhesive absorption groove can be made excellent.

  According to the ink jet head of the present invention, it is possible to greatly suppress the occurrence of excess or deficiency in the amount of the adhesive without depending on the processing accuracy of the members and individual differences in warping due to heating for curing the adhesive, and each ink It is also possible to greatly suppress the clogging of the chamber.

It is a figure in the middle of manufacture of the inkjet head of a 1st embodiment of the present invention, and is a perspective view showing the state where a plurality of ink grooves were formed in a piezoelectric substrate. It is a figure in the middle of manufacture of the inkjet head of 1st Embodiment of this invention, Comprising: It is a perspective view which shows the state which formed the adhesive agent absorption groove | channel in the piezoelectric substrate. It is a figure in the middle of manufacture of the inkjet head of 1st Embodiment of this invention, Comprising: It is a perspective view which shows the state which formed the electrically conductive film in the piezoelectric substrate. It is a figure in the middle of manufacture of the inkjet head of a 1st embodiment of the present invention, and is a perspective view showing the state where an unnecessary conductive film of a piezoelectric substrate was removed. It is a figure in the middle of manufacture of the ink jet head of a 1st embodiment of the present invention, and is a perspective view showing the state where a separation slot was formed in a piezoelectric substrate. It is a figure in the middle of manufacture of the inkjet head of 1st Embodiment of this invention, Comprising: It is a perspective view which shows the state which connected the flexible cable to the piezoelectric substrate. It is a figure in the middle of manufacture of the inkjet head of 1st Embodiment of this invention, Comprising: It is a perspective view which shows the state which adhered the nozzle plate to the piezoelectric substrate. It is a perspective view of the manifold member with which the inkjet head of a 1st embodiment of the present invention is provided. It is a figure in the middle of manufacture of the ink jet head of a 1st embodiment of the present invention, and is a perspective view showing the state where a manifold member was pasted up to a piezoelectric substrate. It is a figure in the middle of manufacture of the inkjet head of 1st Embodiment of this invention, Comprising: It is a fragmentary perspective view which shows the state which adhered the manifold member to the piezoelectric substrate. It is sectional drawing which shows the adhesive agent absorption chamber formed in the piezoelectric substrate of the inkjet head of 2nd Embodiment of this invention. It is sectional drawing which shows the adhesive agent absorption chamber formed in the piezoelectric substrate of the inkjet head of the modification of 2nd Embodiment of this invention. It is a top view which shows the adhesive agent absorption groove | channel formed in the piezoelectric substrate of the inkjet head of the further modification of 2nd Embodiment of this invention. It is a fragmentary perspective view which shows the state which adhered the manifold member to the piezoelectric substrate of the inkjet head of 3rd Embodiment of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

(First embodiment)
Hereinafter, the manufacturing method of the ink jet head according to the first embodiment of the present invention will be described.

(Groove formation process)
First, a dicing blade is scanned in a fixed direction a plurality of times on the piezoelectric substrate 1 that is an actuator member to perform a groove forming process for forming a plurality of ink grooves 2. Zirconate titanate (PZT) was used for the piezoelectric member. A piezoelectric substrate 1 on which a plurality of ink grooves 2 are formed is shown in FIG. In FIG. 1, the hatched portion is the opening 3. Each of the ink grooves 2 is covered with the nozzle plate 4 later, thereby serving as an ink chamber for transmitting pressure to the ink and discharging the ink. In the present embodiment, the size of the piezoelectric substrate 1 is 5 mm × 50 mm, and the thickness is 2 mm. Each ink groove 2 has a depth of 300 μm and a width of 100 μm. The pitch of each ink groove 2 is 200 μm, and the number of grooves is 200. In all the drawings, the number, depth, etc. of each ink groove 2 are not shown accurately for the sake of simplification. The width of each ink groove 2 can be changed by the thickness of the dicing blade used, and the depth of each ink groove can be changed by changing the cutting amount of the dicing blade. In addition, two piezoelectric materials having opposite polarization directions are bonded to the piezoelectric substrate 1 in advance at an approximate center in the depth direction of each ink groove 2 with an adhesive. In this embodiment, a 2 mm piezoelectric substrate 1 is formed by laminating a 0.15 mm thin plate 1a and a 1.85 mm thick plate 1b. When a voltage is applied from the outside, the thin plate portion and the thick plate portion of each ink groove 2 are deformed in opposite directions, so that each ink that is a region surrounded by each ink groove 2 and the nozzle plate 4 is used. Ink is ejected by changing the volume of the chamber.

  Subsequently, an adhesive absorbing groove 5 is formed on the outside of each of the plurality of ink grooves 2 of the piezoelectric substrate 1 by a dicing blade. The piezoelectric substrate 1 on which the adhesive absorbing groove 5 is formed is shown in FIG. The adhesive absorption groove 5 is later covered with the nozzle plate 4 to form an adhesive absorption chamber for absorbing excess adhesive. Unlike the ink grooves 2, the adhesive absorbing grooves 5 are opened only on one side of the piezoelectric substrate 1. In this embodiment, the adhesive absorption groove 5 has a width of 1 mm, a depth of 200 μm, a depth of 2 mm, and the adhesive absorption grooves 5 are formed at four locations as shown in FIG.

  In this embodiment, the adhesive absorbing grooves 5 are formed after the ink grooves 2 are formed. However, the order of formation may be reversed. In any case, it is desirable to continuously form the ink grooves 2 and the adhesive absorption grooves 5. In the piezoelectric substrate 1, each ink groove 2 and the adhesive absorbing groove 5 are formed on the same surface by scanning a dicing blade in the same direction. Therefore, by performing these two steps in succession, the piezoelectric substrate 1 This is because it is possible to save the trouble of re-installing the ink jet head on the processing stage and to shorten the time required for manufacturing the ink jet head. In addition, since the ink grooves 2 and the adhesive absorption grooves 5 are formed without resetting the piezoelectric substrate 1 on the processing stage, the positional accuracy between the ink grooves 2 and the adhesive absorption grooves 5 can be improved. It is.

(Conductive film formation process)
Subsequently, a conductive film forming step for forming a conductive film to be an electrode on the inner wall of each ink groove 2 of the piezoelectric substrate 1 and forming a conductive film to be an electrode lead portion on the side surface of the piezoelectric substrate 1 is performed. . In this embodiment, copper is formed by sputtering. At this time, the film thickness on the inner wall of each ink groove 2 of copper formed was set to 0.5 μm at the thinnest portion. The piezoelectric substrate 1 after the conductive film forming step is shown in FIG. The shaded part is the part where the conductive film is formed. In the conductive film forming step by sputtering in the present embodiment, the conductive film is formed on the entire surface except the surface on the back side of the surface on which the respective ink grooves 2 of the piezoelectric substrate 1 are formed, and the conductive film is also formed on portions other than the intended purpose. . At this time, the thickness of the copper film formed on the side surface where each ink groove 2 of the piezoelectric substrate 1 was opened was 1 μm. The film thickness of the copper film formed on the inner wall of each ink groove 2 and the film thickness of the copper film formed on the side surface of the piezoelectric substrate 1 in which each ink groove 2 is opened are different from each other in the area around the copper depending on the shape. This is due to the difference.

(Conductive film removal process)
Subsequently, a removal process for removing unnecessary conductive film portions formed in the conductive film formation process on the surface of the piezoelectric substrate 1 where the ink grooves 2 are formed is performed. This removal step can be performed, for example, by scanning the upper surface of the piezoelectric substrate 1 a plurality of times with a dicing blade. At this time, it is preferable to slightly grind the surface of the piezoelectric substrate 1 with a dicing blade so that the adjacent ink grooves 2 are reliably insulated from each other on the surface of the piezoelectric substrate 1 where the ink grooves 2 are formed. The piezoelectric substrate 1 after this removal step is shown in FIG. In the piezoelectric substrate 1 after the removal step, a conductive film is formed on the inner walls of the ink grooves 2 and the adhesive absorbing grooves 5 and the side surfaces of the piezoelectric substrate 1.

(Electrode separation process)
Next, a separation process is performed in which the separation groove 7 is formed by scanning the conductive film formed on the side surface of the piezoelectric substrate 1 with a dicing blade a plurality of times in a certain direction. FIG. 5 shows the piezoelectric substrate 1 on which the electrode lead portions 8 corresponding to the respective ink grooves 2 are formed by this separation step. The electrode 6 formed on the inner wall of each ink groove 2 and the electrode lead-out portion 8 are electrically connected on the side surface of the piezoelectric substrate 1 where each ink groove 2 opens. In this embodiment, the depth of the separation groove 7 is 10 μm and the width is 50 μm, and the separation process is performed on the side surface of the piezoelectric substrate 1 where each ink groove 2 is opened. Further, the portion where the separation groove 7 is formed is between the ink grooves 2 and is located at a position where there is no electrical conduction between the adjacent ink grooves 2. Such a separation step was performed on both sides of the side surface of the piezoelectric substrate 1 in which each ink groove 2 was opened. By performing the separation process on both sides, the piezoelectric substrate 1 becomes symmetrical, so that the direction is not mistaken in the subsequent process. Further, when the electrode lead portion on one side is damaged, the yield can be improved because the electrode lead portion on the opposite side can be used.

(Flexible cable connection process)
A conductive member is connected to the electrode lead portion 8 of the piezoelectric substrate 1 thus processed. FIG. 6 shows the piezoelectric substrate 1 to which a conductive member is connected. In the present embodiment, a flexible cable 9 is used as the conductive member, and an ACF connection is used for connection with the electrode lead-out portion 8. The other end of the flexible cable 9 is connected to an external voltage application mechanism directly or via another member in order to eject ink. In this embodiment, the flexible cable is used as the conductive member because the flexible cable can be easily deformed, and thus can be easily used in the process in the subsequent process and can suppress a decrease in yield. However, the flexible cable is not necessarily a flexible cable. There is no need.

(Electrode protective film formation process)
Next, in order to protect the electrode formed on the wall surface of the piezoelectric substrate 1, an electrode protective film (not shown) is formed with a thickness of about 10 μm. This electrode protective film adheres to all exposed surfaces of the piezoelectric substrate 1 and the flexible cable 9 in the formation process. Therefore, the flexible cable 9 that does not need to be attached is previously masked with a masking tape or the like so that the electrode protective film is not attached.

  Further, the connecting portion between the flexible cable 9 and the piezoelectric substrate 1 is reinforced in advance with an adhesive. In the cleaning process, film forming process, etc. that accompanies the electrode protective film formation, there is a problem of dust adhesion or contamination if the film formation surface is held. There is a need to do. Therefore, the work is performed while holding the flexible cable 9, but the connection width is narrow and the adhesion strength is weak, so that the connection part is peeled off and electrical continuity cannot be obtained, or the connection resistance varies. Sometimes. By performing reinforcement with an adhesive, it is possible to obtain adhesion strength that can withstand a cleaning process, a film forming process, and the like associated with the formation of the electrode protective film.

(Adhesion between piezoelectric substrate and nozzle plate)
Next, the nozzle plate 4 is bonded to the piezoelectric substrate 1. The nozzle plate 4 is formed of a polyimide sheet having a thickness of 50 μm. The surface of the nozzle plate 4 is previously coated with a liquid-repellent thin film against ink. In this state, the nozzle holes 10 are processed by an excimer laser so as to be the same as the formation pitch of each ink groove 2 of the piezoelectric substrate 1. The outer size of the nozzle plate 4 has a length equivalent to that of the piezoelectric substrate 1 and has a width that is the sum of the piezoelectric substrate 1 and the manifold members 11a and 11b to be connected later. The adhesive drops the adhesive onto the glass substrate, obtains a uniform adhesive layer by spin coating, and then stamps the piezoelectric substrate 1 on the adhesive layer, thereby transferring the adhesive onto the surface. It is possible to adjust the desired adhesive thickness depending on the number of revolutions and time of spin coating. Further, about half the thickness of the adhesive layer on the glass substrate is transferred to the piezoelectric substrate 1. For bonding, a bonder machine that mounts IC chips on the substrate is used, and the relative positions of the ink grooves 2 formed on the piezoelectric substrate 1 and the nozzle holes 10 formed on the nozzle plate 4 are aligned to bond. Do. FIG. 7 shows a state after bonding the piezoelectric substrate 1 and the nozzle plate.

(Adhesion of piezoelectric substrate and manifold member)
Subsequently, a manifold member is bonded to the piezoelectric substrate 1. FIG. 8 is a perspective view of the manifold member. In the present embodiment, the manifold member includes two members 11a and 11b. The manifold members 11a and 11b are both formed by injection molding of PEEK material. The manifold member 11a is covered with the nozzle plate 4 so that the step portion 12a to be the first common ink chamber 17a, the flow passage portion 13a communicating with the step portion 12a, and the step portion 14a for avoiding interference with the flexible cable. Is formed. The manifold member 11b is formed with a step portion 12b to be the second common ink chamber 17b, a flow passage portion 13b communicating with the step portion 12b, and a step portion 14b for avoiding interference with the flexible cable.

  The flow path portions 13a and 13b preferably have a shape having few broken line portions, stepped portions, flat portions, etc. as much as possible so that the ink flows efficiently without stagnation. In the present embodiment, the next communicating member such as a filter is linear.

  The stepped portions 14 a and 14 b are formed for the flexible cable 9 to pass through in bonding with the piezoelectric substrate 1. With this structure, the flexible cable 9 does not come into contact with the ink flow path, and the flexible cable 9 is prevented from being dissolved or swollen by ink. Of the stepped portions 14a and 14b, the stepped portion 14b does not allow the flexible cable 9 to pass through. However, by making the manifold members 11a and 11b symmetric, members having the same shape can be used.

  In bonding, first, an adhesive is applied to the surfaces of the manifold members 11a and 11b that are in contact with the piezoelectric substrate 1. Then, the manifold members 11a and 11b are pressed against the piezoelectric substrate 1 and fixed, and the adhesive is cured in this state. In this embodiment, an epoxy-based adhesive is used and cured by heating at 80 ° C. The state after curing is shown in FIG.

  At this time, since there are individual differences in the dimensional accuracy of the piezoelectric substrate 1 and the manifold members 11a and 11b, a gap is formed on the contact surface between the piezoelectric substrate 1 and the manifold members 11a and 11b, and the volume of the gap is not constant. In addition, when an adhesive that requires heat curing is used as in this embodiment, the piezoelectric substrate 1 and the manifold members 11a and 11b are warped by heating, but there are individual differences in the degree of warping. The volume of the clearance between the contact surfaces due to warping is not constant. As described above, since the volume of the gap between the contact surfaces is not constant, even if a certain amount of adhesive is applied to the manifold member, the amount of the adhesive is excessive or insufficient. If it is insufficient, a leak occurs, but it is difficult to repair by applying an adhesive later depending on the leaked portion. Therefore, it is necessary to apply a sufficient amount of adhesive in advance so that the adhesive is not insufficient. On the other hand, when the adhesive becomes excessive, excess adhesive overflows from the contact surface. In particular, if excess adhesive flows into each ink chamber, each ink chamber cannot eject ink, resulting in a defective product.

  In the ink jet head of this embodiment, since the adhesive absorbing groove 5 is formed in the piezoelectric substrate 1, it is possible to prevent excess adhesive from flowing into each ink chamber. This will be described with reference to FIG.

  FIG. 10 is a partial perspective view showing a state in which an adhesive is applied to the manifold members 11a and 11b and pressed against the piezoelectric substrate 1 and fixed. For illustration, the nozzle plate 4 is not shown. Each of the ink chambers 15 and the adhesive absorbing chambers 16a and 16b are formed by the piezoelectric substrate 1 and the nozzle plate 4. Excess adhesive overflows from all directions around the contact surface between the piezoelectric substrate 1 and the manifold members 11a and 11b. In particular, as shown by an arrow 18a, the overflowed adhesive flows between the piezoelectric substrate 1 and the nozzle plate 4. The corners work like capillaries and have a high possibility of reaching each ink chamber 15. However, in the ink jet head according to the present embodiment, the adhesive is absorbed by the adhesive absorbing chamber 16 formed in the middle of the path 18a through which the adhesive flows, so that excess adhesive reaches each ink chamber 15. Can be prevented. The same thing occurs in the adhesive absorption chamber 16b. If two adhesive absorption chambers 16a and 16b are in communication with each other and are open on both sides of the piezoelectric substrate 1 as one adhesive absorption chamber, excess adhesive absorbed from one of the openings is present. It may happen that the other opening is reached by capillary action and the adhesive cannot be absorbed from the other opening. However, by adopting a structure in which the adhesive absorbing chamber is opened only on one side of the piezoelectric substrate 1 as in the ink jet head of the present embodiment, it is constant without being affected by the adhesive absorbed from the other openings. The amount of adhesive can be absorbed.

(Adhesion of nozzle plate and manifold member)
Supplying a necessary amount of adhesive between the nozzle plate 4 and the manifold members 11a and 11b by filling the gap between the manifold members 11a and 11b and the nozzle plate 4 and infiltrating with a capillary force. Can do. Thereby, the first common ink chamber 17a and the second common ink chamber 17b are formed. By making the nozzle plate 4 from polyimide, the adhesive penetrating by capillary force can be confirmed through the nozzle plate, and the supply state of the adhesive can be confirmed. In FIG. 10, the first common ink chamber 17a functions as a first common ink chamber for the adhesive absorbing groove 5a, while the second common ink for the adhesive absorbing groove 5b. It functions as a room. The second common ink chamber 17b functions as a first common ink chamber for the adhesive absorption groove 5b, and functions as a second common ink chamber for the adhesive absorption groove 5a. ing.

  Through the above steps, the inkjet head 25 can positively circulate the ink in the immediate vicinity of the nozzle, and the inkjet head can be mass-produced by avoiding excessive adhesive flowing into each ink chamber and becoming a defective product. Can be produced. When the ink is circulated, the ink may be supplied from the flow path portion 13a, and the ink may be discharged from the flow path portion 13b, or vice versa. Moreover, you may make it switch the direction which flows alternately.

(Second Embodiment)
The present embodiment has substantially the same configuration as the first embodiment, but the shape of the adhesive absorption chamber is different. FIG. 11 is a view showing a cross section of the adhesive absorbing chamber 16 cut in a direction parallel to the groove. The groove is formed so that the depth of the groove gradually decreases from the opening of the adhesive absorbing chamber 16 toward the back. With such a structure, the adhesive that has flowed into the adhesive absorption chamber is gradually buried from the back by capillary action, and bubbles are not left in the adhesive absorption chamber. If air bubbles remain in the adhesive absorption chamber, the remaining air expands and is discharged from the adhesive absorption chamber when heated to use an adhesive that requires heat curing. May flow into each ink chamber. Since the adhesive absorption chamber in the inkjet of this embodiment does not leave bubbles in the chamber, it can stably absorb excess adhesive.

  In order to form the adhesive absorbing chamber as shown in FIG. 11, when forming the adhesive absorbing groove 5 in the groove forming step, the method of using the curvature of the dicing blade, or the cutting amount of the dicing blade is continuously set. There are methods such as changing and processing.

In addition, as shown in FIG. 12, the same effect can be obtained by changing the depth of the groove stepwise by intermittently changing the cutting amount of the dicing blade.
Further, the same effect can be obtained even if the width is narrowed from the opening to the back instead of changing the depth of the groove.

  FIG. 13 is a partial view of the piezoelectric substrate 1 as seen from the direction in which the nozzle plate is attached. By using a plurality of dicing blades having different widths, a groove whose width changes stepwise as shown in FIG. 13 can be formed. Further, the same effect can be obtained by changing the depth and width of the groove at the same time so that the sectional area gradually decreases from the opening toward the back.

(Third embodiment)
The present embodiment has substantially the same configuration as the first embodiment, but the position of the bottom of the opening of the adhesive absorption chamber is different. FIG. 14 is a partial perspective view in a state where an adhesive is applied to the manifold members 11 a and 11 b and pressed against the piezoelectric substrate 1 and fixed. For illustration, the nozzle plate 4 is not shown. The bottom of the opening of the adhesive absorbing chamber 16 is formed to be lower than the bottom of the opening of each ink chamber 15. By doing so, the adhesive absorbing chamber adheres to the excess adhesive flowing through the corners of the piezoelectric substrate and the manifold member as indicated by the arrow 18b before the adhesive reaches each ink chamber. Since the agent can be absorbed, it is possible to more effectively prevent the ink from being buried in each ink chamber.

DESCRIPTION OF SYMBOLS 1 Piezoelectric substrate 1a Piezoelectric substrate thin plate 1b Piezoelectric substrate thick plate 2 Each ink groove 3 Opening part 4 Nozzle plate 5,5a, 5b Adhesive absorption groove 6 Electrode 7 Separation groove 8 Electrode extraction part 9 Flexible cable 10 Nozzle hole 11a, 11b Manifold Member 12a, 12b Stepped portion 13a, 13b Channel portion 14a, 14b Stepped portion 15 Each ink chamber 16 Adhesive absorbing chamber 16a, 16b Adhesive absorbing chamber 17a First common ink chamber 17b Second common ink chamber 18a, 18b Excess bonding Agent flow

Claims (5)

A plurality of partition walls arranged substantially parallel to each other in one direction, a plurality of ink grooves formed between adjacent partition walls, and open at both ends, and positioned outside the plurality of ink grooves. And a piezoelectric substrate having an adhesive absorbing groove that opens only at one end;
A nozzle plate arranged to cover the plurality of ink grooves and having a plurality of nozzle holes communicating with the ink grooves;
A first common ink chamber communicating with the opening on one end side of the plurality of ink grooves and communicating with the opening on the one end side of the adhesive absorbing groove;
An ink jet comprising: a second common ink chamber communicating with an opening on the other end side of the plurality of ink grooves. The inkjet head according to claim 1,
The inkjet head according to claim 1, wherein the adhesive absorption groove has a depth that decreases from the opening side to the back side of the adhesive absorption groove. The inkjet head according to claim 1 or 2,
The ink-jet head is characterized in that the adhesive-absorbing groove has a width that becomes narrower from the opening side of the adhesive-absorbing groove toward the back side. In the ink jet head according to any one of claims 1 to 3,
The depth of the opening of the adhesive absorbing groove is deeper than the depth of the opening of the ink groove. An inkjet head manufacturing method for manufacturing the inkjet head according to claim 1, comprising:
A process for forming an ink groove having both ends opened on the piezoelectric substrate and a step for forming the adhesive absorbing groove having only one end opened on the piezoelectric substrate are continuously produced. Method.

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