JP2015013396A - Droplet discharge head and inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge head capable of stabilizing a liquid discharge characteristic without inhibiting a vibration property by setting up a groove receiving an adhesive overflowing from the joint part of a second substrate, and to provide an image formation device equipped with such head.SOLUTION: A droplet discharge head 1 is provided with an actuator substrate 100 comprising: a pressure chamber substrate 20 which comprises a silicon single crystal substrate and forms a liquid flow path 8 and a pressure liquid chamber 5; a nozzle plate 300 covering one side of the pressure liquid chamber; a diaphragm 3 covering the other side of the pressure liquid chamber; a piezoelectric element 2 joined to a liquid chamber-facing part 47 in the pressure liquid chamber of the diaphragm; and the upper and lower electrodes 11 and 10 energizably holding the piezoelectric element in between and joined to the liquid chamber-facing part. The joint part 48 of a second substrate 200 is bonded by an adhesive 49 to a partition wall part 4 of the pressure liquid chamber parting from a liquid discharge energy-generating part D comprising the liquid chamber-facing part of the diaphragm and the piezoelectric element, and a groove 46 receiving the adhesive is formed on the partition wall part of the pressure liquid chamber of the diaphragm.

Description

  The present invention relates to a droplet discharge head including an electro-mechanical conversion element and an ink jet printer including the droplet discharge head.

An ink jet printer (ink jet recording apparatus) using a droplet discharge head is adopted as an image recording apparatus or image forming apparatus such as a printer, a facsimile machine, and a copying apparatus. Here, the droplet discharge head includes a nozzle that discharges ink droplets, a pressurized liquid chamber (also referred to as an ink flow path, a pressure chamber, a liquid chamber, a pressure generation chamber, and the like) that communicates with the nozzle. A liquid discharge energy generating unit for pressurizing ink in the pressurized liquid chamber is provided, and ink droplets are discharged from the nozzles by these units.
As such a liquid discharge energy generating unit, an electro-mechanical conversion element such as a discharge energy generation element (for example, see Patent Document 1) is used to deform and displace a diaphragm that forms the wall surface of the pressurized liquid chamber. Piezo-type that ejects ink droplets, and electrothermal conversion elements such as heating resistors placed in a pressurized liquid chamber. Ink film boiling (the liquid near the interface of the object in contact with the liquid is instantaneous There is a thermal type (bubble type) in which bubbles are generated by ejecting ink droplets when the instantaneous pressure inside the bubbles reaches 30 atm or more in the case of water. Further, a piezo-type actuator has been devised which has a liquid chamber and an electromechanical conversion element directly formed on a Si substrate.

A piezoelectric element, which is one of such electro-mechanical conversion elements, has a property that an electric charge is generated when stress is applied to the piezoelectric body, and the piezoelectric body expands when an electric field is applied. Examples of the piezoelectric body include ternary metal oxides such as lead zirconate titanate and PZT.
By the way, in the actuator substrate including the liquid chamber in the thin film PZT head, the height of the liquid chamber is about 100 μm. However, if the actuator substrate is thinned to the height of the liquid chamber, handling in subsequent processes (conveying in the processing apparatus, between processes) The actuator substrate is easily broken during transportation, etc., and stable production is not possible. Therefore, before the actuator substrate is thinned, the sub-frame substrate on which the liquid flow path and the like are formed is joined with an adhesive to reinforce the actuator substrate.
Since the actuator part (vibrating plate + piezoelectric element) facing the pressurized liquid chamber of the actuator substrate is a movable part, the liquid chamber partition walls separating adjacent liquid chambers are joined so as not to directly contact the subframe substrate. The upper surface of the diaphragm on the actuator substrate side has a convex shape from the surface of the piezoelectric element, and the convex surface portion is in contact with the bonding surface of the subframe substrate.

However, an adhesive having a thickness of about 1 to 4 μm is formed on the subframe substrate side using a thin film transfer technique, and then bonded to the actuator substrate by a general bonding technique. At this time, the adhesive bonded to the convex surface portion of the actuator substrate may protrude from the bonding surface, ooze out to the actuator portion, and solidify at the actuator portion.
When the adhesive is solidified in the actuator portion, the displacement of the diaphragm is suppressed, the original characteristics cannot be obtained, and the characteristics vary between the adjacent actuators.
For this reason, a droplet discharge head having a plurality of actuators has a problem that desired droplet discharge characteristics cannot be secured stably and with high accuracy.

  Therefore, for example, in Patent Document 1 and Patent Document 2, when the substrates are bonded to each other with an adhesive, a recess that becomes a region for escaping excess adhesive is formed in a shape corresponding to the crystallinity of the bonded substrate base material. Yes. Moreover, in patent document 3, in order to absorb the adhesive protrusion of a junction part, the level | step difference is provided in the mutual joining edge part of the board | substrate which mutually overlaps.

  However, the groove formation in Patent Documents 1 and 2 applies anisotropic wet etching, and because of its etching characteristics, there are restrictions on the width and depth of the groove, so the degree of freedom of the shape and depth of the groove is limited. small. Further, in Patent Document 3, a concave step having a size that can reliably receive the adhesive protruding from the joining edge portion of the substrate that overlaps each other is provided. However, a process for manufacturing the concave step portion is required. Therefore, there is a demerit that the manufacturing cost increases.

  According to the present invention, a groove for receiving an adhesive overflowing from the bonding surface of the second substrate is provided in the pressurized liquid chamber partition wall away from the liquid discharge energy generating unit, and the adhesive flows out to the liquid chamber facing part. An object of the present invention is to provide a liquid droplet ejection head capable of stabilizing the liquid ejection characteristics without hindering the vibration characteristics of the liquid ejection energy generation unit by blocking, and an image forming apparatus equipped with the liquid droplet ejection head.

The present invention has the following configuration in order to achieve the above object.
The droplet discharge head according to the present invention includes a pressure chamber substrate formed of a silicon single crystal substrate and forming a liquid flow path portion and a pressurized liquid chamber, a nozzle plate covering one side of the pressurized liquid chamber, and the pressurizing member A diaphragm that covers the other side of the liquid chamber, a piezoelectric element that is bonded to the liquid chamber facing portion of the pressurized liquid chamber of the vibrating plate, and a piezoelectric element that is sandwiched so as to be energized and bonded to the liquid chamber facing portion An actuator substrate having an upper electrode and a lower electrode, and a second portion of the diaphragm in the pressurized liquid chamber partition portion separated from the liquid chamber facing portion of the diaphragm and the liquid discharge energy generating portion formed of a piezoelectric element. In the droplet discharge head in which the bonding portions of the substrates are overlapped and bonded with an adhesive, a groove for receiving the adhesive is formed in the pressurized liquid chamber partition wall of the diaphragm.

  According to the present invention, a groove that is a reservoir of excess adhesive is formed in the pressurized liquid chamber partition wall that is separated from the liquid chamber facing portion that forms the drive region of the diaphragm. In this way, the excess adhesive that overflows from the joint surface of the second substrate is received by the groove provided in the pressurized liquid chamber partition wall on the outer peripheral side of the liquid discharge energy generating portion that forms the drive region, and the adhesive Can be prevented from flowing out to the opposite part of the liquid chamber that forms the drive area of the vibration plate, preventing the vibration characteristic of the liquid discharge energy generation part of the actuator substrate from being disturbed, and stabilizing the liquid discharge characteristic of the droplet discharge head it can.

FIG. 3 is a cutaway perspective view of a main part of a droplet discharge head according to an embodiment of the present invention. FIG. 2 is a side sectional view in a pressurized liquid chamber of the droplet discharge head of FIG. 1. FIG. 2 is a front cross-sectional view of a pressurized liquid chamber of the droplet discharge head of FIG. 1. (A)-(e) is process drawing explaining a pre-manufacturing process in the cross-sectional schematic diagram of the pressurized liquid chamber long side long direction B of the droplet discharge head of FIG. (F)-(h) is process drawing explaining the middle stage of a manufacturing process by the cross-sectional schematic diagram of the pressurized liquid chamber long side long direction B of the droplet discharge head of FIG. (I)-(j) is process drawing explaining the latter stage of a manufacturing process with the cross-sectional schematic diagram of the pressurized liquid chamber long side long direction B of the droplet discharge head of FIG. (A)-(e) is process drawing explaining the manufacturing process pre-stage in the cross-sectional schematic diagram of the pressurization liquid chamber short side long direction A of the droplet discharge head of FIG. (F)-(i) is process drawing explaining the middle stage of a manufacturing process by the cross-sectional schematic diagram of the pressurized liquid chamber short side long direction A of the droplet discharge head of FIG. FIG. 4J is a schematic cross-sectional view of the liquid drop ejection head of FIG. 1 in the short side length direction A of the pressurized liquid chamber, and FIG. It is a principal part cross section of the droplet discharge head which concerns on the other Example of this invention. It is a principal part cross section of the droplet discharge head which concerns on the other Example of this invention. It is a principal part notch sectional drawing of the actuator board | substrate of the droplet discharge head which concerns on the other Example of this invention. It is a perspective view of a cartridge provided with the droplet discharge head which is other embodiments of the present invention. It is a perspective view of the inkjet recording device provided with the cartridge which is other embodiment of this invention. It is a schematic side view of the inkjet recording device of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the embodiments and modifications, components such as members and components having the same function or shape are denoted by the same reference numerals as much as possible, and once described, the description thereof is omitted.
The present invention has the following characteristics with respect to a droplet discharge head. Grooves are formed in the pressurized liquid chamber partition wall provided in the vicinity of the liquid chamber facing portion of the diaphragm to which the piezoelectric element forming the liquid discharge energy generating portion is bonded, and this functions as a reservoir for excess adhesive It is characterized by. The excess adhesive that overflows from the bonding surface of the second substrate is received by the groove provided in the pressurized liquid chamber partition wall, and the excess adhesive flows out from the pressurized liquid chamber partition wall to the liquid chamber facing portion. Can be prevented. Therefore, it is possible to prevent variation in vibration displacement due to the adhesive protruding to the liquid discharge energy generating portion of the vibration plate that forms the drive region of the actuator substrate, and to provide a highly accurate and reliable liquid droplet discharge head and the same liquid droplet discharge head Can be realized.

First, with reference to FIGS. 1-2, the droplet discharge head as Embodiment 1 of this invention is demonstrated.
1 is a perspective view of a droplet discharge head having a piezoelectric actuator according to the present invention, FIG. 2 is a cross-sectional view of the liquid chamber long side direction of FIG. 1, and FIG. 3 is a cross-sectional view of the liquid chamber short side length direction of FIG. . As shown in FIG. 1, the droplet discharge head 1 is of a side shooter type that discharges droplets from nozzle holes provided in a substrate surface portion.
The droplet discharge head 1 includes an actuator substrate 100, a sub-frame substrate 200 which is a second substrate bonded to one side of the actuator substrate 100, and a nozzle substrate 300 which is a third substrate bonded to the other side. It is formed by.

The actuator substrate 100 includes a pressure chamber substrate 20 that forms a common liquid chamber (liquid flow path portion) 8 and a pressurized liquid chamber 5, and overlaps the pressure chamber substrate 20 to cover one side of the pressurized liquid chamber 5 and a nozzle hole 6. And the vibration plate 3 that overlaps the pressure chamber substrate 20 and covers the other side of the pressurized liquid chamber 5 are joined to each other.
A plurality of pressurized liquid chambers 5 are arranged on the pressure chamber substrate 20 in a straight line in the longitudinal direction (vertical direction in FIG. 2) A in sequence. Further, inside the pressure chamber substrate 20, a pressurized liquid chamber partition 4 that partitions the adjacent pressurized liquid chambers, a common liquid chamber 8 that sequentially faces each pressurized liquid chamber 5, and each pressurized liquid A fluid resistance portion 7 is provided in the chamber 5 to guide the liquid in the common liquid chamber 8 by using a throttling function.

On the outside of the liquid chamber facing portion 47, which is the portion of the diaphragm 3 facing the pressurized liquid chamber 5, the piezoelectric element 2 sandwiched between the lead-out wiring layers (the layered molded body of the piezoelectric body 12 formed here) (Referred to as piezoelectric element 2). The lead-out wiring layer is composed of individual electrodes (upper electrodes) 11 and common electrodes (lower electrodes) 10 that sandwich the piezoelectric body 12 so as to be energized. The liquid chamber facing portion 47 of the vibration plate 3, the piezoelectric element 2, the individual electrode 11, and the common electrode 10 constitute a liquid discharge energy generating portion D that forms a driving means.
The subframe substrate 200 that is overlapped and bonded to one side of the actuator substrate 100 forms a second substrate. In the subframe substrate 200, the diaphragm 3 bends when the droplet supply port 66 for supplying droplets from the outside to the common liquid chamber 8 through the common droplet flow path 9 and the liquid discharge energy generating unit D are driven. Counterbore 67 is formed so that

In addition, nozzle holes 6 are formed in the nozzle substrate 300 at positions corresponding to the individual pressurized liquid chambers 5. Further, a passivation as an interference member is provided for the purpose of protecting the lead wiring layer composed of the individual electrode (upper electrode) 11 and the common electrode (lower electrode) 10 sandwiched between the sub-frame substrate 200 which is overlapped and bonded to the actuator substrate 100. A film 50 is formed.
Here, the actuator substrate 100 and the sub-frame substrate 200 are mutually in contact with the pressurized liquid chamber 5, the counterbore 67, and the liquid chamber facing portion 47 of the diaphragm 3 between them, and the portions serving as the outer peripheral region surrounding them are mutually Overlap and join.

Here, in the pressurized liquid chamber partition wall portion 4 provided in the vicinity of the outer peripheral region surrounding each liquid chamber facing portion 47 of the vibration plate 3, a passivation film 50 (interference member) is polymerized, and the passivation film 50 is sandwiched between The frame substrate 200 (second substrate) is bonded to the bonding portion 48.
Here, in the vicinity of a portion where the joint portion 48 of the actuator substrate 100 and the sub-frame substrate 200, which is a feature of the present invention, is overlapped, a groove 46 is formed for storing an excess portion of the adhesive 49 used when joining the two. The adhesive 49 does not protrude from the liquid chamber facing portion 47 that is the vibration plate region.

Here, in particular, the groove 46 is formed in a portion adjacent to the bonding portion 48 of the passivation film 50 that overlaps the pressurized liquid chamber partition wall portion 4. Grooves 46 are respectively formed in the passivation films 50 of the adjacent partition walls of the pressurized liquid chambers apart from the joints 48, and the respective grooves can function to receive the adhesive overflowing from the joints 48.
In this case, the groove 46 can be formed in the passivation film 50 (interference member), the excess adhesive can be prevented from flowing into the liquid chamber facing portion 47 that forms the drive region, and the groove is not formed in the diaphragm. The process is improved and the processing is facilitated.

  As shown in FIGS. 1 and 2, the actuator substrate 100 includes the diaphragm 3 that forms a wall surface on one side of the pressurized liquid chamber 5, and the piezoelectric element 2 provided outside the liquid chamber facing portion 47 of the diaphragm 3. The liquid discharge energy generating part D is formed. Further, the surface of the diaphragm 3 facing the common liquid chamber 8 is formed with a common ink supply path 9 from which ink as droplets can be supplied from the outside.

  In the droplet discharge head 1 formed in this way, the recording liquid is supplied from the control unit (not shown) based on the image data in a state where each pressurized liquid chamber 5 is filled with a liquid, for example, a recording liquid (ink). A pulse voltage of 20 V, for example, is applied to the individual electrode 11 corresponding to the nozzle hole 6 to be discharged by an oscillation circuit through the connection hole 30 formed in the lead-out wiring 40 and the interlayer insulating film 45. By applying this voltage pulse, the piezoelectric element 2 contracts in the longitudinal direction B of the pressurizing fluid chamber 5 when the piezoelectric element 2 itself contracts in the direction parallel to the diaphragm 3 due to the electrostrictive effect. Bend. As a result, the pressure in the pressurized liquid chamber 5 rises rapidly, and the recording liquid is discharged from the nozzle holes 6 communicating with the pressurized liquid chamber 5. Next, after the pulse voltage is applied, the contracted piezoelectric element 2 returns to its original position, and the deflected diaphragm 3 returns to its original position, so that the inside of the pressurized liquid chamber 5 is compared with the inside of the common liquid chamber 8. Ink supplied from the outside via the droplet supply port 66 is supplied to the pressurized liquid chamber 5 from the common droplet supply path 9 and the common liquid chamber 8 via the fluid resistance portion 7. By repeating this, droplets can be ejected continuously, and an image is formed on a recording medium (paper) disposed facing the droplet ejection head.

Next, each example of the droplet discharge head according to the embodiment of the present invention will be sequentially described in detail.
Example 1
Next, a manufacturing process of a droplet discharge head similar to the droplet discharge head shown in FIGS. 1 to 3 described above is shown in (a) to (e) of FIG. f) to (h), (i) to (j) in FIG. 4C, (a) to (e) in FIG. 5A, (f) to (i) in FIG. With reference to (j) of 5 (C), the manufacturing steps: [A] to [J] will be sequentially described.
Here, (a) in FIG. 4 (A) to (j) in FIG. 4 (C) are cross-sectional schematic views in the long side length direction B of the pressurized liquid chamber of the droplet discharge head as viewed in the same direction as described in FIG. The figure is shown. (A) in FIG. 5 (A) to (j) in FIG. 5 (C) are schematic cross-sectional views in the direction A in the short side length direction of the pressurized liquid chamber of the droplet discharge head as viewed in the same direction as described in FIG. Show.
[A]: Process A will be described along (a) of FIG. 4 (A) and (a) of FIG. 5 (A).
Here, as the pressure chamber substrate 20 constituting the main part of the actuator substrate 100 of the droplet discharge head 1 described with reference to FIGS. 2 and 3, the diaphragm 3 is placed on a silicon single crystal substrate (for example, 400 μm thick) having a plane orientation (110). A film is formed. The diaphragm 3 may be either a single layer or a laminated film as long as the function as the diaphragm and subsequent process consistency are ensured.

For example, as a material of the diaphragm 3, a silicon oxide film, a polysilicon film, an amorphous silicon film, or a silicon nitride film is formed by lamination using LP-CVD so as to have a desired diaphragm rigidity. In view of process consistency, diaphragm rigidity, and overall stress of diaphragm 3, the number of stacked layers is preferably about 3 to 7 layers. In order to ensure adhesion with the later common electrode 10, the uppermost layer of the diaphragm 3 is a silicon oxide film formed by LPCVD. Thereafter, for example, a common electrode 10 layer made of TiO ₂ and Pt is formed by sputtering to a thickness of 50 nm and 100 nm, respectively.

[B]: Process B will be described along (b) of FIG. 4 (A) and (b) of FIG. 5 (A).
PZT is formed as a piezoelectric body 12 on the common electrode 10 in a plurality of times by, for example, spin coating, and finally formed into a piezoelectric element 2 having a thickness of 2 μm. Next, the upper electrode 11 of Pt is sputtered (a method in which argon gas particles are collided with a target (substance desired to be a thin film), and a target component repelled by the impact is deposited on the substrate to generate a thin film), for example, 100 nm. Form a film. Here, the film formation method of the piezoelectric body 12 is not limited to the spin coating method (an apparatus that forms a thin film by centrifugal force by rotating a smooth glass substrate or the like at high speed), and other film formation methods can be used. For example, a sputtering method or an ion plating method (a combined technique of vacuum deposition and plasma, which in principle uses gas plasma to make part of the evaporated particles ion or excited particles and activate and deposit them) may be used. . Furthermore, air sol method, sol-gel method (Glass (Jelly-like solid) is produced through hydrolysis, condensation polymerization, etc. of glassy and ceramic solution-like substances, and the solvent is removed by heat treatment to obtain glass or ceramics) Alternatively, the film may be formed by an inkjet method or the like. Then, a litho-etching method (a technique in which an etch mask having a fine pattern is formed on the surface of a substrate such as a semiconductor by light (electron beam) lithography and the like and a surface process is performed using a corrosive action such as a chemical). Thus, the individual electrode 11 and the piezoelectric body 12 are patterned in order to form the piezoelectric element 2 at a position corresponding to the pressurized liquid chamber 5 to be formed later.
Thereafter, the common electrode 10 is patterned by a lithoetch method. At this time, the common electrode 10 layer at the location that will later become the common liquid chamber flow path 9 is also patterned.

[C]: Process C will be described with reference to (c) of FIG. 4 (A) and (c) of FIG. 5 (A).
Next, an interlayer insulating film 45 is formed in order to insulate the common electrode 10 and the piezoelectric element 2 from the lead wiring 40 to be formed later. As the interlayer insulating film 45, for example, a SiO2 film is formed by plasma CVD. The interlayer insulating film 45 may be a film other than the SiO2 of the plasma CVD method as long as it does not affect the piezoelectric element 12 and the electrode material and has an insulating property. Next, a connection hole 30 for connecting the individual electrode 11 and the lead wiring 40 is formed by a lithoetch method. Although not shown here, when the common electrode 10 is also connected to the lead-out wiring 40, a connection hole is similarly formed.

[D]: Process D will be described with reference to (d) of FIG. 4 (A) and (d) of FIG. 5 (A).
Next, as the lead-out wiring 40, for example, TiN / Al is formed to a thickness of 30 nm / 1 um by sputtering. TiN is alloyed with the heat history of the subsequent process by the contact of Pt, which is the material of the individual electrode 11 or the common electrode 10, and Al, which is the material of the lead-out wiring 40, at the bottom of the connection hole 30, and the volume change It is applied as a barrier layer to prevent alloying in order to prevent film peeling and the like due to stress caused by the above.
In addition, the wiring pattern 42 is also formed at a location that becomes the joint portion 48 with the subsequent subframe substrate 200.
[E]: Process E will be described along (e) of FIG. 4 (A) and (e) of FIG. 5 (A).
Next, as the passivation film 50, a silicon nitride film having a thickness of 1000 nm is formed by plasma CVD, for example.

[F]: Process F will be described along (f) in FIG. 4B and (f) in FIG.
Thereafter, the litho-etching method is also used to open the liquid discharge energy generating portion D that forms the actuator portion with the lead wire pad portion 41 of the lead wire 40 and the common droplet flow path 9 portion. In addition, a groove 46 is formed in which surplus adhesive is accumulated when the pressurized liquid chamber partition wall 4 on the actuator substrate 100 side, which is a feature of the present invention, and the joint portion 48 of the subframe substrate 200 are joined.
[G]: Process G will be described along (g) in FIG. 4 (B) and (g) in FIG. 5 (B).
Next, the diaphragm 3 is removed by the litho-etching method at the location that becomes the common liquid chamber flow path 9 and the later common liquid chamber 8.

[H]: Step H will be described along (h) in FIG. 4B and (h) in FIG.
Next, the sub-frame substrate 200 in which the counterbore 67 is formed at a position corresponding to the actuator portion 48 and the actuator substrate 100 are bonded with the adhesive 49 through the bonding portion 48. At this time, the adhesive 49 is applied to the subframe substrate 200 side by a thickness of about 1 to 4 μm by a general thin film transfer device. At this time, the excess adhesive 49 protruding from the joint portion 48 stays in the groove 46 and does not protrude to the subsequent drive region. Then, the pressure chamber substrate 20 which forms the main part of the actuator substrate 100 in order to form the subsequent pressurized liquid chamber 5, common liquid chamber 8, and fluid resistance portion 7 is formed to a desired thickness t (for example, thickness 80 μm: FIG. 5). (B) (see (i)) is polished by a known technique. Etching may be used in addition to the polishing method.

[I]: Step I will be described along (i) of FIG. 4 (C) and (i) of FIG. 5 (B).
Next, by a litho method (a resist is coated on a silicon substrate and irradiated with ultraviolet rays, and the irradiated portion is passed through a “developer” to create a pattern), a pressurized liquid chamber 5, a common liquid chamber 8, The partition 4 other than the fluid resistance 7 is covered with a resist. Thereafter, anisotropic wet etching is performed with an alkali solution (KOH solution or TMHA solution) to form the pressurized liquid chamber 5, the common liquid chamber 8, and the fluid resistance portion 7.
The pressurized liquid chamber 5, the common liquid chamber 8, and the fluid resistance portion 7 may be formed by dry etching using an ICP etcher other than anisotropic etching with an alkaline solution.

[J]: Process J will be described along (j) in FIG. 4C and (j) in FIG. 5C.
Next, a nozzle substrate 300, which is a third substrate having a nozzle hole 6 opened, is bonded to a position corresponding to each separately formed pressurized liquid chamber 5 to generate liquid discharge energy that forms a droplet supply port 66 and an actuator unit. The sub-frame substrate 200 which is the second substrate provided with the counterbore 67 corresponding to the position of the part D is bonded to the first substrate 100, whereby the droplet discharge head 1 is completed.
In Example 1, the depth of the groove 46 for storing the adhesive 49 was equivalent to the thickness of the passivation film 50. However, the depth of the groove 46 was increased to the interlayer insulating film 45 of the lead wiring 40 as shown in FIG. By securing or further deepening the diaphragm 3 as shown in FIG. 7, the tolerance of the amount of excess adhesive 49 accumulated increases, and liquid ejection energy generation, which is a more stable drive region of the excess adhesive 49, is generated. The flow into the part D can be prevented. The depth of the groove 46 can be changed by etching only the interlayer insulating film 45 by changing only the etching time in FIG. Further, when etching up to the diaphragm 3 as shown in FIG. 7, the material of the common electrode 10 corresponding to the groove 46 may be etched in advance when the common electrode 10 is etched.

Further, the groove 46 is formed continuously in the direction of the pressurized liquid chamber partition wall 4 that divides the pattern between the adjacent pressurized liquid chambers 5. As a result, it is possible to achieve the actuator substrate 100 that is highly reliable and stable, because the effect of suppressing the flow of the excess adhesive into the liquid discharge energy generating portion D that is the drive region can be ensured to the maximum extent.
Further, the groove 46 may be formed continuously along the drive region longitudinal direction A or intermittently as long as it can prevent the surplus adhesive 49 from flowing into the liquid discharge energy generating portion D that is the drive region. It may be formed automatically.
For example, when the groove 46 is formed intermittently, it is possible to optimize the effects of the strength of the diaphragm 3 and the pressurized liquid chamber partition 4, the bonding strength, and the flow of the adhesive, A stable and reliable actuator substrate 100 can be obtained.

In the first embodiment, since the bonding portion 48 between the actuator substrate 100 and the subframe substrate 200 is pressure bonded using an adhesive, the adhesive 49 always protrudes from the bonding portion 48. In consideration of this point, the groove 46 is formed in the pressurized liquid chamber partition wall portion 4 so that the protruding adhesive 49 does not flow into the liquid discharge energy generating portion D that is an actuator portion. The flow of the adhesive 49 can be reliably prevented. Therefore, the liquid chamber facing portion between the bits of each droplet discharge head 1 (the interval between the nozzle holes of the adjacent droplet discharge heads 1) due to the flow of the adhesive 49 into the liquid discharge energy generating portion D which is the drive region. Relative driving variations are eliminated, stable driving is possible, and a highly reliable and stable droplet discharge head can be realized with high yield.
Further, the present invention can be provided in a cartridge in which the droplet discharge head 1 is integrated or a droplet recording apparatus in which the droplet discharge head 1 is mounted.

(Example 2)
In the first embodiment, a groove 46 is formed in the pressurized liquid chamber partition wall portion 4 in the vicinity of the joint portion 48 in order to prevent the flow into the liquid discharge energy generating portion D that is a drive region of the adhesive 49 at the time of joining. Excess adhesive 49 was accumulated in the groove 46.
In the second embodiment, as shown in FIG. 8, the groove 46 is formed in the pressurized liquid chamber partition wall portion 4 in the vicinity of the bonding portion 48, and further, the bonded portion of the subframe substrate 200 in the pressurized liquid chamber partition wall portion 4. A groove 46 a is formed also on the joint surface f 1 overlapping with 48, that is, both.
Here, the groove 46a is also formed in the bonding surface f1 of the passivation film 50 on the pressurized liquid chamber partition wall 4 side, so that accumulation of excess adhesive 49 can be allowed to accumulate, and the liquid discharge which is a driving region than in the first embodiment can be achieved. It is possible to more reliably prevent the adhesive 49 from flowing into the energy generating part D.
Further, by providing the groove 46 on the bonding surface f1 of the passivation film 50 on the pressurized liquid chamber partition wall 4 side, it is possible to expect an improvement in bonding strength due to the anchor effect. Accordingly, a more reliable and stable actuator substrate can be realized.

Here, the structure such as the depth of grooves other than the groove 46a of the pressurized liquid chamber partition wall 4 on the actuator substrate 100 side in FIG. 8 may be the structure shown in FIGS.
The manufacturing method is the same as that of the first embodiment, and only the point where the groove 46a is formed in the joint 48 is an additional configuration.
Therefore, compared to the first embodiment, the liquid droplet ejection head 1 that is more reliable and stable can be realized with a high yield.
Further, the present invention can also be applied to a cartridge in which the droplet discharge head 1 is integrated and a droplet recording apparatus on which the droplet discharge head 1 is mounted.
Furthermore, the amount of excess adhesive flowing out of the joint can be suppressed by forming a groove for collecting the surplus adhesive in the joint. For this reason, the effect of preventing the adhesive from flowing into the drive region is further improved than the structure of the second aspect.

Next, a cartridge in which the droplet discharge head 1 according to Embodiment 2 of the present invention is integrated will be described with reference to FIG.
An ink cartridge 80 shown in FIG. 9 is obtained by integrating a droplet discharge head 1b having nozzles 81 and the like, and an ink tank 82 for supplying ink to the droplet discharge head 1b. As described above, when the ink tank 82 is the integrated droplet discharge head 1b, the liquid discharge energy generation unit D (see FIGS. 2 and 3) that constitutes the actuator unit is made highly accurate, highly densified, and highly reliable. Thus, the yield and reliability of the ink cartridge 80 can be improved, and the cost of the ink cartridge 80 can be reduced.

Next, an ink jet recording apparatus (image forming apparatus) according to Embodiment 3 of the present invention will be described in detail.
Here, an example of an ink jet recording apparatus (image forming apparatus) on which the droplet discharge head 1 is mounted will be described with reference to a perspective view of FIG. 10 and a schematic side view illustrating a configuration of a mechanism unit of FIG.
The ink jet recording apparatus 90 is provided with a printing mechanism 91 inside the apparatus main body, and a paper feed cassette (or a paper feed tray) 93 capable of stacking a large number of sheets 92 from the front side in the lower part of the apparatus main body. Removably attach the. Further, it has a manual feed tray 94 (shown in a closed state in FIG. 11) that is opened to manually feed the paper 92. The ink jet recording apparatus 90 takes in the paper 92 fed from the paper feed cassette 93 or the manual feed tray 94, records a required image by the printing mechanism 91, and then discharges it to the paper discharge tray 95 mounted on the rear side. Make paper.

The printing mechanism 91 holds a main guide rod 96, a secondary guide rod 97, and a carriage 98, which are guide members horizontally mounted on left and right side plates (not shown), so as to be slidable in the main scanning direction.
Here, the carriage 98 is slidably fitted to the main guide rod 96 on the rear side (sheet conveyance downstream side), and the front side (sheet conveyance upstream side) is slidably mounted on the sub guide rod 97. Yes. In order to move and scan the carriage 98 in the main scanning direction X, a timing belt 104 is stretched between a driving pulley 102 and a driven pulley 103 that are rotationally driven by the main scanning motor 101. Further, the timing belt 104 is fixed to the carriage 98, and the carriage 98 is reciprocated by forward and reverse rotation of the main scanning motor 101.

In the carriage 98, a droplet discharge head 1 for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) is provided with a plurality of ink discharge ports (nozzles) in the main scanning direction. They are arranged in a direction crossing X, and are mounted with the ink droplet ejection direction facing downward.
Also, each ink cartridge 80 (see FIG. 9) for supplying ink of each color to the droplet discharge head 1 is replaceably mounted on the carriage 98 of the ink jet recording apparatus, and a color image is stably printed. .
The ink cartridge 80 is provided with an air inlet communicating with the atmosphere at the upper side, and a supply port for supplying ink to the liquid droplet ejecting head 1 (having the same configuration as the liquid droplet ejecting head 1b in FIG. 9) at the lower side. Has a porous body filled with ink, and the ink supplied to the droplet discharge head 1 is maintained at a slight negative pressure by the capillary force of the porous body. Further, although the droplet discharge head 1 of each color is used as the droplet discharge head 1, a single droplet discharge head having nozzles for discharging ink droplets of each color may be used.

  On the other hand, in order to convey the paper 92 set in the paper feed cassette 93 downward to the droplet discharge head 1, the paper feed roller 105 and the friction pad 106 for separating and feeding the paper 92 from the paper feed cassette 93, and the paper 92 A guide member 107 that guides the sheet 92, a conveyance roller 108 that reverses and conveys the fed paper 92, a conveyance roller 109 that is pressed against the circumferential surface of the conveyance roller 108, and a feeding angle of the sheet 92 from the conveyance roller 108. And a tip roller 110 for defining. The transport roller 108 is rotationally driven through a gear train by a sub-scanning motor.

In addition, a printing receiving member 111 that is a paper guide member is provided to guide the paper 92 sent out from the transport roller 108 corresponding to the movement range of the carriage 98 in the main scanning direction on the lower side of the droplet discharge head 1. Yes. A conveyance roller 112 and a spur 113 that are rotationally driven to send the paper 92 in the paper discharge direction are provided on the downstream side of the printing receiving member 111 in the paper conveyance direction, and the paper 92 is further discharged to the paper discharge tray 95. A roller 114, a spur 115, and guide members 116 and 117 that form a paper discharge path are disposed.
During recording by the ink jet recording apparatus 90, the droplet discharge head 1 is driven in accordance with the image signal while moving the carriage 98, thereby discharging ink onto the stopped sheet 92 to record one line. Thereafter, after the sheet 92 is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 92 reaches the recording area, the recording operation is terminated and the paper 92 is discharged.

  In addition, a recovery device 117 for recovering the ejection failure of the droplet ejection head 100 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 98. The recovery device 117 includes a capping unit, a suction unit, and a cleaning unit. During printing standby, the carriage 98 is moved to the recovery device 117 side, and the droplet discharge head 1 is capped by the capping unit to keep the discharge port portion in a wet state, thereby preventing discharge failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and a stable ejection state is maintained.

Further, when a discharge failure occurs, the discharge outlet (nozzle) of the liquid droplet discharge head 1 is sealed with a capping unit, and bubbles with ink are sucked out from the discharge port by a suction unit through the tube. Ink, dust, etc. adhering to the ink are removed by the cleaning means, and the ejection failure is recovered.
In such an ink jet recording apparatus 90, a high-quality liquid cartridge to which a piezoelectric element forming a liquid discharge energy generating portion excellent in durability and reliability can be used. Further, a cartridge to which the present invention is applied is equipped with a droplet discharge head 1 to which the present invention is applied. Since the liquid droplet ejection head 1 employs a piezoelectric element that forms a liquid ejection energy generating portion having excellent durability and reliability, stable ink ejection characteristics can be obtained. The printed matter produced by the ink jet recording apparatus 90 using the cartridge 80 to which the droplet discharge head 1 is applied has improved image quality.

In the above description, the case where the droplet discharge head 1 as described in the first embodiment is used in the ink jet recording apparatus 90 has been described. However, the present invention is applied to an apparatus that discharges droplets other than ink, for example, a liquid resist for patterning. You may apply the droplet discharge head 1 of invention.
Although the ink jet recording apparatus to which the droplet discharge head 1 is attached is a color image forming apparatus, the present invention can also be applied to a monochrome image forming apparatus. The present invention can also be applied to image forming apparatuses such as copying machines and facsimile machines.

DESCRIPTION OF SYMBOLS 1 Droplet discharge head 2 Piezoelectric element 3 Diaphragm 4 Pressurized liquid chamber partition part 5 Pressurized liquid chamber 6 Nozzle hole 7 Fluid resistance part 8 Common liquid chamber (liquid flow path part)
10 Common electrode (lower electrode)
11 Individual electrode (upper electrode)
12 Piezoelectric material 20 Pressure chamber substrate 40 Lead-out wiring 46 Groove 47 Liquid chamber facing portion 48 Joint portion (subframe substrate)
49 Adhesive 80 Ink cartridge 90 Inkjet recording apparatus (image forming apparatus)
100 Actuator substrate 200 Subframe substrate (second substrate)
300 Nozzle plate D Liquid discharge energy generator (drive means)

Japanese Patent No. 4572371 JP 2007-111902 A JP 2009-143014 A

Claims (8)

A pressure chamber substrate formed of a silicon single crystal substrate and forming a liquid flow path section and a pressurized liquid chamber; a nozzle plate covering one side of the pressurized liquid chamber; and a vibration plate covering the other side of the pressurized liquid chamber; A piezoelectric element that is bonded to the liquid chamber facing portion of the pressurized liquid chamber of the diaphragm, and an upper electrode and a lower electrode that are sandwiched so as to be energized and bonded to the liquid chamber facing portion. An adhesive substrate, and a bonding portion of the second substrate is overlapped with an adhesive agent in a partition portion of the pressurized liquid chamber separated from the liquid discharge energy generating portion composed of the piezoelectric chamber and the liquid chamber facing portion of the diaphragm. In the adhered droplet discharge head,
A droplet discharge head, wherein a groove for receiving the adhesive is formed in the partition wall of the pressurized liquid chamber of the diaphragm. The droplet discharge head according to claim 1,
The droplet discharge head, wherein the groove is formed in a portion of the pressurized liquid chamber partition wall adjacent to the joint portion of the second substrate. The droplet discharge head according to claim 1,
The liquid droplet ejection head, wherein the groove is formed in both the pressurized liquid chamber partition wall and the joint outside the joint. The droplet discharge head according to any one of claims 1 to 3,
The droplet discharge head, wherein the second substrate and the vibration plate are joined to each other with an interference member disposed so as to overlap the partition wall of the pressurized liquid chamber, and the groove is formed in the interference member. . The droplet discharge head according to any one of claims 1 to 4,
The liquid droplet ejection head, wherein the groove pattern is formed continuously in the direction of a pressurized liquid chamber partition wall partitioning the adjacent pressurized liquid chambers. The droplet discharge head according to any one of claims 1 to 4,
The droplet discharge head according to claim 1, wherein the groove pattern is intermittently formed in a direction of a partition wall of a pressurized liquid chamber that partitions the adjacent pressurized liquid chambers. In a liquid cartridge in which a droplet discharge head that discharges droplets and an ink tank that supplies recording liquid to the droplet discharge head are integrated,
A liquid cartridge, wherein the droplet discharge head is the droplet discharge head according to claim 1. In an image forming apparatus equipped with a droplet discharge head for discharging droplets,
An image forming apparatus, wherein the droplet discharge head is a droplet discharge head according to claim 1 or a droplet discharge head of a liquid cartridge according to claim 7.

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