JP3487089B2 - Multilayer inkjet recording head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated ink jet recording head formed by joining an actuator unit made of ceramics and a flow path substrate made of metal.

[0002]

2. Description of the Related Art For example, as disclosed in Japanese Patent Laid-Open No. 6-40035, a piezoelectric vibrating plate is attached to a partial area of an elastic plate that constitutes a pressure generating chamber, and the piezoelectric vibrating plate is flexibly displaced. The ink jet recording head that generates ink droplets by changing the volume of the pressure chamber is capable of displacing a large area of the pressure generating chamber, and thus has the characteristic that ink droplets can be generated stably. There is.

Such a recording head is usually composed of a plurality of actuator units A, B and C, which are produced by sintering a pressure generating chamber, a vibration plate and a piezoelectric vibration plate as shown in FIG. A plurality of actuator units A, which are roughly divided into a single flow path forming unit D made of a metal plate formed corresponding to the nozzle opening row,
B and C are fixed to the flow path unit D with an adhesive.

[0004]

As described above, in fixing a plurality of actuator units, the heat-welding film is interposed between the actuator unit and the flow-passage unit, and the heat-welding film is melted by heating while applying pressure. The technique is adopted.

However, since the joint area is large, the air trapped between the heat-welding film, the actuator unit and the flow path unit expands, causing joint failure or requiring long-term heating. There are problems such as warpage due to the difference in thermal expansion due to the difference.

Further, as miniaturization progresses, vibration of the piezoelectric vibrator propagates to a common ink chamber, and so-called crosstalk occurs which vibrates the meniscus of another pressure generating chamber via the ink here. There are problems such as deterioration of print quality.

The present invention has been made in view of the above problems, and its purpose is to quickly solve problems such as inconvenience caused by thermal bonding between the flow path unit and the actuator unit, and crosstalk. It is an object of the present invention to provide a stackable inkjet recording head that can be solved.

[0008]

In order to solve such a problem, in the laminated ink jet recording head of the present invention, a pressure generating chamber and a pressure generating element for pressurizing the pressure generating chamber are provided. An actuator unit provided with the actuator unit, an ink supply port forming substrate having an ink supply port and a communication hole to which the actuator unit is fixed and which communicates at both ends of the pressure generation chamber, and the pressure generation via the ink supply port. A common ink chamber forming substrate having a common ink chamber communicating with the chamber and a communication hole communicating with the pressure generating chamber, and the other communication port while sealing the other surface of the common ink chamber forming substrate And a flow path unit formed by joining a nozzle plate having a nozzle opening connected to the pressure generating chamber via the ink supply port forming substrate. In a region facing the serial common ink chamber and the pressure generating chamber, by forming a concave portion facing the actuator unit.

[0009]

Since the recess of the ink supply port forming substrate forms a space between the ink supply port forming substrate and the actuator unit, the thermally expanded air is allowed to escape there to reduce the pressure, and the adhesive area is limited to the necessary minimum. The difference in thermal expansion is absorbed by the adhesive layer, and the air layer formed by the recess blocks the vibration from the piezoelectric vibrator from propagating to the common ink chamber.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments.

FIG. 1 is an assembled perspective view showing the entire recording head of the present invention with a heat-welding film omitted, and FIG. 2 is a sectional view showing the structure in the vicinity of a pressure generating chamber of one actuator unit. In the figure, reference numeral 2 is a first cover plate, which is composed of a thin plate of zirconia with a thickness of about 10 μm, and a drive electrode 5 is formed on the surface thereof so as to face a pressure generating chamber 4 described later, A piezoelectric vibrating plate 3 made of PZT or the like is fixed thereon.

The pressure generating chamber 4 contracts and expands in response to the flexural vibration of the piezoelectric vibrating plate 3 to eject ink droplets from the nozzle openings 28, and also eject ink from the common ink chamber 23 via the ink supply port 20. Suction.

A spacer 7 is a zirconia (Z) having a thickness suitable for forming the pressure generating chamber 4, for example, 150 μm.
rO ₂ ), etc., is formed by forming through holes in a ceramics plate, and both sides are sealed by a second lid body 8 and a first lid body 2 described later to form the pressure generating chamber 4 described above. There is.

Reference numeral 8 denotes a second lid, which is also a communication hole 9 for connecting an ink supply port 20 and a pressure generating chamber 4, which will be described later, to a ceramic plate such as zirconia, a nozzle opening 28, and the pressure generating chamber 4. A communication hole 10 for connecting the end is formed, and is fixed to the other surface of the spacer 7.

These members 2, 7 and 8 are assembled in the actuator unit 1 without using an adhesive by molding a clay-like ceramic material into a predetermined shape and stacking and firing it. .

Reference numeral 21 denotes an ink supply port forming substrate which doubles as a fixed substrate of the actuator unit 1 and can also be provided with a connecting member to the ink tank, so that it has the highest rigidity among the members in the recording head. It is a required member. For this reason, metals such as non-rust steel and ceramics having ink resistance are selected as the materials.

As shown in FIGS. 2 and 3, the surface of the ink supply port forming substrate 21 facing the common ink chamber 23 is at a position facing the pressure generating chamber 23 and outside, that is, the actuator unit 1. A recess 21a that opens to the side is formed.

When a metal is used as the ink supply port forming substrate 21, such a recess 21a is formed on the surface of the ink supply port forming substrate 21 facing the ink chamber 23 for common ink, as shown in FIG. The concave portion 40 is formed by a press or the like (FIG. 4A), and the convex portion 41 on the other surface is polished (FIG. 4A).
(B)) The surface is finished (FIG. 4 (c)).

As another method, an etching protection film 43 having a window 42 is formed on the surface of the ink supply port forming substrate 21 facing the common ink chamber (FIG. 5A), and only one surface is formed. After the recesses 44 are formed by etching (FIG.
(B)), the etching protection film 43 is removed (FIG. 5).
Methods such as (c)) can be applied.

As yet another method, as shown in FIG. 6, two metal thin plates 50 and 51 made of non-rust steel or the like are laminated and bonded via an adhesive film 52 to prepare a plate material, and the adhesive film 52 is etched. As a stopper, one metal thin plate 50
Of the recess 21a of the substrate is selectively removed by etching, or the recess 21a is formed on the surface of the substrate.
There is a processing method for forming a thick portion by masking a portion corresponding to the above and electroforming.

Further, as shown in FIG. 7, PPS and PI
The film 54 is laminated and joined between the two metal thin plates 50 and 51 via the adhesive films 55 and 56, and the portion corresponding to the recess 21a of one metal thin plate 50 is selectively used as the etching stopper with the film 54. There is also a processing method of removing it by etching.

Referring back to FIGS. 1 and 2, the ink supply port forming substrate 21 is provided with a common ink chamber 23 (to be described later) and an ink supply port 20 for connecting the pressure generation chamber 4 to one end of the pressure generation chamber 4 side. A communication hole 24 that is provided and is connected to the nozzle opening 28 is provided on the other end side of the pressure generating chamber 4.

Further, ink introduction ports 22, 22, 22 into which ink flows from an ink tank (not shown) are formed at positions outside the fixing area of the actuator unit 1.

A common ink chamber forming substrate 25 has a thickness suitable for forming the common ink chamber 23, for example, 150.
A plate material having corrosion resistance such as stainless steel having a thickness of μm is provided with a through hole 26 that connects the through hole corresponding to the common shape of the ink chamber 23 and the nozzle opening 28 of the nozzle plate 27. There is.

The ink supply port forming substrate 21, the common ink chamber forming substrate 25, and the nozzle plate 27 are disposed between them by a heat-welding film or adhesive bonding layers 32, 3 of an adhesive.
It is fixed by 3 and put together in the flow path unit 30.

On the surface of the ink supply port forming substrate 21 of the flow path unit 30, as shown in FIG. 8, the heat-welding film 31 and the actuator unit 1 are laminated in order and heated while pressing them. Then, the temperature of the bonding region is rapidly increased, and the heat-welding film 31 is rapidly softened and melted.

By this heating, the air confined between the hot melt film 31 and the actuator unit 1 and the flow path unit 30 is thermally expanded, but the recess 21a of the ink supply port forming substrate 21 and the heat weld film 31 are formed. Window 3
The pressure rise is alleviated in the space formed by 1a and the joint surface is reliably bonded.

For example, on the ink supply port forming substrate 21, the length L = 8.73 mm, the width W = 1.74 mm, and the thickness 15 of the thin portion.
If the recess 21a having a thickness of 25 μm is formed, 1 × 10
Since it exhibits elasticity of about minus fifteen cubic meters / pascal, it is possible to sufficiently absorb the pressure rise due to the thermal expansion at the time of joining.

Further, the thickness T '(FIG. 2) of the air layer formed by the concave portion 21a and the adhesive layer sufficiently functions as a vibration shielding material against the vibration propagated from the actuator unit 1. This prevents vibration generated in the pressure generating chamber 4 when ejecting ink droplets from propagating to the common ink chamber 23 and inducing vibration in the ink there, which adversely affects ink supply to the pressure generating chamber 4. can do.

In the figure, reference numeral 14 denotes a common electrode formed on the surface of the piezoelectric vibrating plate 3, and 15 denotes a flexible cable for connecting to an external device.

In this embodiment, when a drive signal is applied to the piezoelectric vibrator 3, the piezoelectric vibrator 3 flexurally vibrates and contracts the pressure generating chamber 4. As a result, the ink in the pressure generating chamber 4 is pressurized and ejected as an ink droplet from the nozzle opening 28.

At this time, the vibration of the piezoelectric vibrator 3 propagated through the actuator unit 1 is attenuated by reflection and absorption due to the extreme impedance difference due to the air layer in the recess 21a of the ink supply port forming substrate 21. To reach the common ink chamber 23.

Therefore, it is possible to greatly reduce the propagation of vibrations that induce pressure fluctuations in the other pressure generating chambers 4 via the common ink chamber 23, which has been a problem in the past.

Further, since the joint area between the ink supply port forming substrate 21 and the actuator unit 1 can be easily limited, the difference in thermal expansion due to the difference in the materials of the two is absorbed and the durability of the adhesive strength against heat cycle is improved. Can be improved.

By the way, as shown in FIG. 6, two metal thin plates 50, 51 are laminated and bonded via an adhesive film 52 to prepare a plate material, and the adhesive film 52 is used as an etching stopper, and one metal thin plate 50 is When the portion corresponding to the recess 21a is selectively removed by etching, there is a possibility that the boundary 51a of the recess 21a is exposed and the adhesive strength is slightly lowered due to the action of the etching liquid in this region. is there.

In this state, when the heat-welding film 31 is placed on the surface of the thin metal plate 50 and the actuator unit 1 is heated and adhered while being pressed, stress concentrates on this boundary and causes peeling, which causes the heat-melt film 31 to be separated. There is a possibility that the air trapped between the actuator unit 1 and the flow path unit 30 may thermally expand and penetrate into the interior from the boundary 51a to cause a large separation.

FIG. 9 shows two such thin metal plates 50,
An embodiment suitable for forming the recess 21a by bonding 51 with the adhesive film 52 and etching one surface thereof is shown. The position of the recess 21a is formed on the common ink chamber forming substrate 25. The common ink chamber 23 side is offset by a predetermined amount Δd so that it is easily bent in this region.

According to this embodiment, even when a part of stress is applied by being pressed during the above-mentioned heat welding, as shown in FIG. 10, a layer composed of the metal thin plates 50 and 51 and the heat welding film 52. Are elastically deformed as a unit, the boundary portion 51a
It is possible to prevent the stress from being intensively concentrated on the sheet, and to suppress the progress of peeling of the thin plate 50 due to the expansion of air.

FIG. 11 also shows the two thin metal plates 50 and 5.
1 shows another embodiment for avoiding the problem that occurs when 1 is bonded via the adhesive film 52. In this embodiment, a predetermined thin metal plate 50 to be etched is arranged in the nozzle opening arrangement direction. Ribs 5 extending in the width direction at intervals
A plurality of recesses 21b, 21c and 21d are formed by etching so as to leave 0b and 50c. The rib 5 is preferably located at a position away from the ink inlet 22.
The distances L1, L2, and L3 are increased as the distance increases from 0a and 50b (L1 <L2 <L3).

According to this embodiment, in the boundaries of the recesses 21b, 21c and 21d which are subjected to stress or the like, the longitudinal directions which are relatively easy to turn are attracted to each other by the ribs 50a and 50b. Is prevented from rising. As the ink inlet 22 is farther away, the rib 50
Since the intervals L1, L2, L3 of a and 50b are increased and the area of the recess 21d farthest from the ink guide port 22 is increased, peeling is performed without unnecessarily suppressing the compliance on the back side of the common ink chamber. Can be prevented.

FIG. 12 shows another embodiment for preventing the above-mentioned peeling. In this embodiment, the boundary of the thin metal plate 50 forming the recess 21a in the longitudinal direction facing the recess 21a. At predetermined intervals on the convex portions 50d, 50d
... is provided.

According to this embodiment, the convex portions 50d, 50d
It is possible to increase the joint area at the boundary due to ..., and also to prevent curling.

When it is difficult to process the deep recess 21a in the ink supply port forming substrate 21 with high accuracy,
As shown in FIG. 13, shallow recesses 21e and 21f can be formed so as to face each other from both surfaces of the ink supply port forming substrate 21.

Also in this embodiment, one of the recesses 2 is also formed.
1e can absorb a pressure increase due to thermal expansion at the time of heat welding, and further prevent the vibration from the actuator unit 1 from propagating to the common ink chamber in combination with the concave portion 21f on the other surface. The joint area can be reduced as much as possible to absorb the difference in thermal expansion.

Such an ink supply port forming substrate is shown in FIG.
As shown in FIG. 4, windows 42, 4 are provided at positions corresponding to the concave portions 21e, 21f of the ink supply port forming substrate 21 on both sides.
The etching protection films 43 and 46 having 5 are provided (see FIG.
(A)), etching is performed from both sides to form recesses 21e,
After forming 21f (FIG. 14B), it can be formed by removing the etching protection films 43 and 46 (FIG. 14C).

Providing the recesses 21e and 21f on both surfaces in this manner is useful for shortening the processing time and ensuring accuracy because the etching depth is shallow.

In the above-described embodiment, as described with reference to FIG. 2, the pressure generating element composed of the first cover plate 2, the drive electrode 5, the piezoelectric vibrating plate 3 and the common electrode 14 is provided on the spacer 7. Although the description has been given by taking as an example the one using the laminated structure, the pressure generating element may have various modes.

That is, as shown in FIG. 15, the common electrode 100 is provided on the lower surface of the first lid member for sealing the pressure generating chamber 4.
Area of the piezoelectric vibrating layer 101 facing the pressure generating chamber 4 by forming the individual electrode 102 in the area facing the pressure generating chamber 4 on the upper surface thereof. Alternatively, it is also possible to configure the structure in which only one is flexibly displaced.

Further, as shown in FIG. 16, the first lid member is formed by the common electrode 100, and the piezoelectric vibrator 103 and the individual electrode 104 are provided on the pressure generating chamber 4 side of the common electrode 100. Or, if necessary, the common electrode 10
Alternatively, a layer suitable for elastic deformation, for example, a thin film of zirconia may be laminated on the surface of No. 0.

Further, as shown in FIG. 17, Joule heat is generated on the surface of the lid member that seals the spacer 7 on the pressure generating chamber 4 side or on the pressure generating chamber side of another member that partitions the pressure generating chamber 4. The element 106 may be provided so that the Joule heat generating element 106 is heated by a drive signal to vaporize and pressurize the ink in the pressure generating chamber.
Reference numeral 107 in the figure indicates a protective layer.

Although only the pressure generating means and the spacer 7 have been described in the above embodiment, the construction of the recording head other than that is the same as the second lid 8 and the flow path unit 30 shown in FIG.
The configuration of the above-described embodiment, such as a laminated structure of

[0052]

As described above, according to the present invention, the concave portion allows the air that has been thermally expanded at the time of bonding to escape on the surface facing the actuator unit of the ink supply port forming substrate to reduce the pressure, and the bonding area is required. The difference in thermal expansion between the two can be absorbed by the adhesive layer while limiting to the minimum. Further, since the concave portion is formed in the region facing the pressure generating chamber, the air layer formed by the concave portion functions as a vibration isolation member, and prevents the vibration from the piezoelectric vibrator from propagating to the common ink chamber.

[Brief description of drawings]

FIG. 1 is an assembled perspective view showing an embodiment of an ink jet recording head of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the ink jet recording head of the present invention with a structure in the vicinity of a pressure generating chamber of one actuator unit.

FIG. 3 is a diagram showing a positional relationship between a recess formed in a substrate for forming an ink supply port and a common ink chamber.

FIG. 4A to FIG. 4C are diagrams showing a process for forming a recess in an ink supply port forming substrate, respectively.

5A to 5C are views showing another embodiment for forming a concave portion on a substrate for forming an ink supply port, respectively.

FIG. 6 is a sectional view showing another embodiment of the ink supply port forming substrate.

FIG. 7 is a cross-sectional view showing another embodiment of the ink supply port forming substrate.

FIG. 8 is a diagram showing a step of bonding an actuator unit and a flow path unit.

FIG. 9 is a cross-sectional view showing an example in which an ink supply port forming substrate formed by laminating two thin plates is used.

FIG. 10 is an enlarged view showing the vicinity of a recess.

FIG. 11 is a cross-sectional view showing another example in which an ink supply port forming substrate configured by laminating two thin plates is used.

FIG. 12 is a cross-sectional view showing another embodiment in the case where an ink supply port forming substrate constituted by laminating two thin plates is used.

FIG. 13 is a cross-sectional view showing another embodiment of the ink jet recording head of the present invention with the structure near the pressure generating chamber of one actuator unit.

14A to 14C are views showing another embodiment of the method for manufacturing the ink supply port forming substrate of the recording head, respectively.

FIG. 15 is a diagram showing an example in which the pressure generating element of the recording head of the present invention is made of a piezoelectric material having a one-piece structure that also serves as a first lid member.

FIG. 16 is a diagram showing an embodiment in which the pressure generating element of the recording head of the present invention is provided inside the pressure generating chamber.

FIG. 17 is a diagram showing an example in which the pressure generating element of the recording head of the present invention is configured by a Joule heat generating element.

FIG. 18 is a perspective view showing an example of an ink jet recording head in which a plurality of actuator units are provided in a flow path unit.

[Explanation of symbols]

1 Actuator unit 2 First lid 3 Piezoelectric diaphragm 4 Pressure generation chamber 7 Spacer 8 Second lid 9, 10 communication holes 20 ink supply port 21 Ink supply port forming substrate 21a recess 22 Ink inlet 23 common ink chamber 27 nozzle plate 28 nozzle openings 30 flow path unit 31 Thermal welding film

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiki Okumura 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Fujio Akabane 3-3-5 Yamato, Suwa-shi, Nagano Prefecture Sei Co-Epson Co., Ltd. (72) Inventor Tomoaki Abe 3-5 Yamato, Suwa-shi, Nagano Seiko Epson Co., Ltd. (56) Reference JP-A-6-234218 (JP, A) JP-A-6- 99578 (JP, A) JP-A-4-179549 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (11)

(57) [Claims] 1. An actuator unit having a pressure generating chamber and a pressure generating element for pressurizing the pressure generating chamber, a communication hole to which the actuator unit is fixed and which communicates at both ends of the pressure generating chamber. A common ink having an ink supply port forming substrate having an ink supply port, a common ink chamber communicating with the pressure generating chamber via the ink supply port, and a communication hole communicating with the pressure generating chamber A flow path unit formed by joining a chamber forming substrate and a nozzle plate that seals the other surface of the common ink chamber forming substrate and has a nozzle opening that is connected to the pressure generating chamber via each of the communication holes. And a concave portion facing the actuator unit in a region facing the common ink chamber and the pressure generating chamber of the ink supply port forming substrate. Laminated ink jet recording head and formed by. 2. A first lid member made of ceramic which has a piezoelectric vibrating plate on its surface to form a vibrating member, and a ceramic whose one surface is sealed by the lid member to form a pressure generating chamber. An actuator unit in which a spacer is integrally joined by firing, and an ink supply port forming substrate made of metal having a communication hole to which the actuator unit is fixed and which communicates at both ends of the pressure generating chamber and an ink supply port And a common ink chamber forming substrate having a common ink chamber communicating with the pressure generating chamber via the ink supply port and a communication hole communicating with the pressure generating chamber, and the common ink chamber forming substrate The other surface is sealed, and a flow path unit formed by joining a nozzle plate having a nozzle opening connected to the pressure generating chamber through each of the communication holes is connected. As well as, in a region facing the common ink chamber and the pressure generating chamber of the ink supply port forming substrate, the multilayer ink jet recording head obtained by forming a recessed portion that faces the actuator unit. 3. The ink supply port forming substrate is configured by joining two metal thin plates through an adhesive layer, and the recess partially uses one of the metal thin plates as an etching stopper. The laminated ink jet recording head according to claim 1, wherein the laminated ink jet recording head is formed by removing. 4. The ink jet recording head according to claim 1, wherein a peripheral edge of the recess is provided so as to be offset to a common ink chamber side formed on the common ink chamber forming substrate. 5. The recess is formed by being divided into a plurality of regions in the arrangement direction of the nozzle openings.
The ink jet recording head according to 1. 6. The ink jet recording head according to claim 5, wherein the area of the divided area is set so as to increase as the distance from the port through which ink flows from the outside increases. 7. The laminated ink jet recording head according to claim 1, wherein a plurality of convex portions that project toward the concave portion of the metal thin plate that forms the concave portion are formed. 8. The laminated ink jet recording head according to claim 1, wherein recesses are formed on both surfaces of the ink supply port forming substrate facing the common ink chamber. 9. An actuator unit having a pressure generating chamber and a pressure generating element for pressurizing the pressure generating chamber, a communication hole to which the actuator unit is fixed and which communicates at both ends of the pressure generating chamber. A common ink having an ink supply port forming substrate having an ink supply port, a common ink chamber communicating with the pressure generating chamber via the ink supply port, and a communication hole communicating with the pressure generating chamber A flow path unit formed by joining a chamber forming substrate and a nozzle plate that seals the other surface of the common ink chamber forming substrate and has a nozzle opening that is connected to the pressure generating chamber via each of the communication holes. While bonding and, in the area facing the common ink chamber of the ink supply port forming substrate,
Forming a recess facing the actuator unit,
The ink supply port forming substrate is configured by joining two metal thin plates through an adhesive layer, and the recess is formed by partially removing one metal thin plate using the adhesive layer as an etching stopper. The formed multilayer ink jet recording head. 10. An actuator unit including a pressure generating chamber and a pressure generating element for pressurizing the pressure generating chamber, a communication hole to which the actuator unit is fixed and which communicates at both ends of the pressure generating chamber. A common ink having an ink supply port forming substrate having an ink supply port, a common ink chamber communicating with the pressure generating chamber via the ink supply port, and a communication hole communicating with the pressure generating chamber A flow path unit formed by joining a chamber forming substrate and a nozzle plate that seals the other surface of the common ink chamber forming substrate and has a nozzle opening that is connected to the pressure generating chamber via each of the communication holes. And a concave portion facing the actuator unit is formed in a region of the ink supply port forming substrate facing the common ink chamber. It is configured by being divided into a plurality of regions in the arrangement direction of the nozzle openings, and the area of the divided regions is
A multi-layer ink jet recording head that is set to become larger as the ink inlet from the outside becomes farther. 11. An actuator unit having a pressure generating chamber and a pressure generating element for pressurizing the pressure generating chamber, a communication hole to which the actuator unit is fixed and which communicates at both ends of the pressure generating chamber. A common ink having an ink supply port forming substrate having an ink supply port, a common ink chamber communicating with the pressure generating chamber via the ink supply port, and a communication hole communicating with the pressure generating chamber A flow path unit formed by joining a chamber forming substrate and a nozzle plate that seals the other surface of the common ink chamber forming substrate and has a nozzle opening that is connected to the pressure generating chamber via each of the communication holes. While bonding and, in the area facing the common ink chamber of the ink supply port forming substrate,
Forming a recess facing the actuator unit,
A multi-layer ink jet recording head having a plurality of convex portions protruding toward the concave portion of a thin metal plate forming the concave portion.