JP3384235B2 - Ink jet 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 an ink jet recording head that ejects ink droplets to form an ink image on a recording medium such as recording paper.

[0002]

2. Description of the Related Art In recent years, with the increasing demand for low-priced ink jet printers with high speed and high printing quality, it is required that each member constituting the ink jet type recording head has high processing density and processing accuracy.

Materials such as plastics, ceramics, and glass are generally used for the spacer member constituting the pressure generating chamber. (U.S. Pat. No. 4,057,807, U.S. Pat. No. 3,972,474, etc.) However, such a technique cannot meet the high definition and high precision demanded by the ink jet recording head in recent years. As a solution to this problem, there have been disclosed many techniques for etching a silicon wafer and using it as a component of an ink jet recording head. For example, Japanese Patent Publication No. 58-40509 is known as an ink jet recording head in which a flow path is formed of a silicon substrate, and a (100) silicon substrate is used in this example.

An example of an ink jet type recording head using a (110) silicon substrate is "KE Petersen,
`Fabrication of an Integrated, Planar Silicon Ink-
Jet Structure, 'IEEE transactions on electron devic
es, vol.ED-26, No.12, December 1979 "are known.

US Pat. No. 4,311,008 also discloses a technique for forming a pressure generating chamber by etching a silicon wafer.

As is well known, a so-called multi-nozzle type ink jet recording head in which a plurality of nozzle openings are arranged on one substrate is provided with a nozzle plate having a plurality of nozzle openings, a pressure generating chamber and an ink supply flow. spacer for partitioning the road, and the other surface laminated second plate to seal, fixed, by accumulating the pressure in the pressure generating chamber Ri by the piezoelectric vibrator or the heating elements, achieving the effective use of energy While configured to fly ink drops.

In order to improve the recording density of the ink jet type recording head, the pitch of the nozzle opening row tends to be small, and the size of the pressure generating chamber must be reduced accordingly. With the miniaturization of the pressure generating chamber, in an ink jet recording head that relies on a piezoelectric vibrator as a pressure generating source, the amount of displacement of the piezoelectric vibrator can be increased, so that the piezoelectric vibrator expands and contracts in the longitudinal direction. A mode piezoelectric vibrator is convenient.

In the longitudinal vibration mode piezoelectric vibrator, a large displacement amount can be obtained as described above, so that the contact area with the pressure generating chamber can be made extremely small, and therefore the array pitch can be made small. However, on the other hand, there is a problem that it is not possible to ensure the compliance of a size required for ink ejection.

That is, since the compliance of the pressure generating chamber required for ink ejection is determined by the elasticity of the second plate, not only the width of the pressure generating chamber becomes smaller, but also the piezoelectric vibrator in the longitudinal vibration mode has the second characteristic. Since it is fixed to the plate, the amount of elastic deformation in the pressure generation region of the second plate becomes small, and there is a problem that it is not possible to secure compliance of a size required for ink droplet ejection.

[0010]

Therefore, we have formed a slit in the wall between the pressure generating chambers so that a part of the wall can be deformed by pressure to ensure the required compliance. No. 7-276625), but in order to further increase the density of the ink jet recording head, it is necessary to make the wall thinner, so that it is impossible to obtain a thickness enough to make a slit in the wall. come.

In order to increase the speed of ink droplet ejection, it is desirable to shorten the natural vibration cycle of ink in the pressure generating chamber.

In order to further increase the density and speed of the ink jet recording head, the present invention provides a novel ink jet recording head capable of providing a pressure generating chamber with compliance of a size required for ink ejection. To provide.

[0013]

[Means for Solving the Problems ] To solve the above problems
The present invention provides a nozzle plate in which a plurality of nozzle openings are arranged in a row.
And nozzle openings arranged on the nozzle plate
The spacer member that separates each nozzle opening, and the spacer
A pressure generating member for sealing one surface of the member,
Both sides of the spacer member are secured by the generating member and the nozzle plate.
The pressure generating chamber, which is configured by sealing, can be
Ink jet that pressurizes and ejects ink droplets from the nozzle opening
In the jet recording head, the pressure generating chamber is arranged so that the first (111) plane orthogonal to the crystal orientation (110) plane of the silicon surface of the spacer member and the (110) plane of the surface are opposed to each other .
And by the second (111) plane with an inclination of approximately 35 degrees
It is partitioned Te, a nozzle opening formed by the second (111) plane
It is characterized in that a part of the wall in the direction orthogonal to the mouth arrangement direction is set to have a thickness that can be deformed by pressure.

Furthermore, the pressure generating chamber is the second (111) plane.
The has two surfaces, a portion of each of the walls formed by the second (111) plane of each, it is characterized in that it is set to the deformable thickness by pressure.

Further, by anisotropic etching of the surface of the spacer member on the nozzle plate side of the silicon surface, the second recesses (111) are formed in the direction orthogonal to the nozzle opening arrangement.
It is characterized in that it is formed so as to face the wall formed by the surface.

[0016]

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

1 and 2 (a) and 2 (b) show an embodiment of an ink jet recording head according to the present invention, in which reference numeral 1 designates nozzle openings 2 and 2. 2.
.., the nozzle plate 3 in which is bored, 3 is the pressure generating chamber 4,
Spacers 4, 7 that partition the ink supply ports 5, 5, 5 ... and the reservoir 6 are second plates, and both surfaces of the spacer 3 are the nozzle plates 1. It is sealed by the second plate 7 and integrated into an ink jet recording head.

The pressure generating chambers 4, 4, 4, ... Are partitioned by walls 8 and 10, respectively, and the nozzle openings 2, 2, 2, ...
-A space 9 is arranged adjacent to the nearby wall 8. Wall 8
Is selected to have a thickness that allows elastic deformation when pressure is applied to the ink for ejecting ink droplets, about 5 μm in this embodiment, and is orthogonal to the arrangement direction of the nozzle openings 2, 2, 2. Are arranged in the direction. An adhesive is used to fix the spacer member 3 and the plates 1 and 7 to each other.
An alloy-like method without using an adhesive, such as eutectic bonding, can be applied.

The other end of the longitudinal vibration mode piezoelectric vibrator 11 whose one end is fixed to a base (not shown) in the pressure generating chamber 4 of the ink jet recording head constructed as described above is connected to the island portion 12 of the second plate 7. When it is attached and a drive signal based on print data is applied to it, the piezoelectric vibrator 11 expands and the second plate 7 bends toward the pressure generating chamber 4 side,
Pressure is generated in the pressure generating chamber 4.

As shown in FIG. 3, this pressure causes the wall 8 defining the pressure generating chamber 4 to be deformed toward the space 9 side and the second plate 7 to be expanded and displaced outward, and at the same time, the nozzle opening. Ink droplets are ejected from 2. At this time, the wall 8
By deforming, the pressure other than that used for ejecting ink droplets in the pressure generating chamber 4 is absorbed, and the wall 10 is hardly deformed. Since the wall 8 does not physically have a portion where the pressure propagates adjacently, the pressure does not propagate to the adjacent pressure generating chambers 4, and an interaction occurs when the adjacent walls are driven by print data. do not do. Also, the wall 8
Is formed in the vicinity of the nozzle opening 2 and the portion having the compliance is arranged in the vicinity of the nozzle opening 2. Therefore, the nozzle meniscus moving by driving is stabilized early, and unstable ejection or variation in ejection is caused. You can hold it down.

FIGS. 4A and 4B show another embodiment of the ink jet recording head of the present invention. The pressure generating chambers 41, 41, 41 ...
Is partitioned by. The wall 13 has a first (111) plane 101 orthogonal to the crystal orientation (110) plane 100 of the silicon surface of the spacer member 31, and separates the adjacent pressure generating chamber 41. The wall 14 is the (110) plane 1 of the surface.
Second (111) plane 102 having an inclination of 00 and about 35 degrees
When the pressure is applied to the ink for ejecting the ink droplet, the thickness is selected to be elastically deformable, which is about 5 μm in this embodiment, and the space is formed by the recess formed by etching from one side. 15 are arranged. In addition, the space 15 may be arranged on both of the two walls 14 as required so that both of the two walls 14 are elastically deformable.

The spacer member 31 includes an ink supply port 5,
The spacer member 31 is formed by the nozzle plate 1 and the second plate 7 which have a shape for partitioning 5, 5, ... And the reservoir 6 and have the nozzle openings 2, 2, 2 ,. Both sides are sealed and integrated in an ink jet recording head.

According to this embodiment, the other end of the piezoelectric vibrator 11 is attached to the island portion 12 of the second plate 7 as shown in FIG. 5, and a drive signal based on the print data is applied to the island portion 12 as described above. The piezoelectric vibrator 11 expands, the second plate 7 bends toward the pressure generating chamber 41, pressure is generated in the pressure generating chamber 41, and an ink droplet is ejected from the nozzle opening 2. At the same time, the wall 14 is deformed and the pressure generating chamber 41 is deformed. Pressures other than those used for ejecting ink droplets in 41 are absorbed. Wall 13
Has a stronger shape as a structural body than the wall 10 of the above-described embodiment and does not deform, so that pressure propagation does not occur in the adjacent pressure generating chambers 41.

Since the surface of the spacer member 31 to be fixed to the nozzle plate 1 of the wall 14 has an inclination of 35 degrees with respect to the thickness of the wall, it can be wider than the width of the thickness, so that there is a degree of freedom in fixing. Therefore, it is easy to optimize the compliance amount of the wall 14. Further, the wall 14 has a structure arranged near the nozzle opening 2 and acts to soften the impact of the movement of the nozzle meniscus as described above, stably suppressing the discharge variation in a short time and improving the print quality. Can be planned.

An embodiment of the method for manufacturing the space member 31 of the present invention will be described below with reference to FIGS. 6 and 7.

First, as shown in FIG. 6A, a silicon wafer 200 whose surface has a crystal plane orientation of (110) plane.
Is heated to 900 to 1100 ° C. and placed in a high-temperature gas containing an oxidizing agent such as oxygen and water vapor to diffuse oxygen atoms on the surface thereof. In this embodiment, the silicon oxide film 201 having a thickness of 1.7 μm is formed by this thermal oxidation treatment.
Was formed. The silicon oxide film 201 plays a role of a mask in an anisotropic etching process described later, and its forming means is not limited to the above-described thermal oxidation process, but may be a CVD (chemical vapor deposition) method, an ion implantation method, an anode. The oxidation method may be used. In addition to the silicon oxide film, a silicon nitride film, a so-called p-type silicon film containing boron or gallium atoms, or a so-called n film containing arsenic or antimony atoms.
A type silicon film may be formed.

Next, as shown in FIG. 6B, a pattern is formed on the silicon wafer 200 with a resin resist 202 so that the pressure generating chamber 41 can be constituted by the (111) plane, as shown in FIG. As shown in FIG. 6C, when the resin resist is removed after selectively removing the silicon oxide film 201 with an acid etching solution such as an aqueous solution of hydrofluoric acid, the mask of the patterned silicon oxide film 201 is removed. The pattern appears.

Next, when the silicon wafer is anisotropically etched with an etching solution such as an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide, the etching rate of which changes depending on the crystal orientation, the process shown in FIG. After that, the process ends in the state shown in FIG. As a result, the through hole 103 is formed and the recess 104 is formed. In this example, the silicon wafer was anisotropically etched with a 20% by weight sodium hydroxide aqueous solution heated to 80 ° C. to obtain a shape as shown in FIG. 7B.

Next, a protective film 203 is formed as shown in FIG. 7C in order to obtain resistance to ink and affinity with ink. The type of film to be formed and the forming means are the same as those of the mask pattern process described above, but it is most preferable to form the protective film of silicon oxide by thermal oxidation.

The pressure generating chamber 41 formed in this way
Shows a second (111) plane 102 in which the through-hole 103 has a diamond shape as shown in FIGS.

The second (111) plane 102 is a silicon wafer plane, that is, the (110) plane 100 to the through hole 10.
Structure shown in FIG. 4 appear in the three directions with about 35 ° taper is Ru obtained. Since the second (111) surface 102 is used as one surface of the wall 14, the wall 14 having the compliance function can be arranged in the direction perpendicular to the nozzle opening arrangement direction. Further, although not shown, in the state of FIG. 6E, a pattern is formed from the side of the (110) plane 100 so that the supply port 5 can be formed again by using a resin resist, and the supply port 5 is etched by the same method as described above. Formed in.

With this structure, it is possible to manufacture an ink jet type recording head which secures sufficient compliance for ejection even if the nozzle opening arrangement pitch is narrow. Moreover, since the wall 14 can be formed by patterning at the same time, proper compliance can be obtained without problems such as positional accuracy.

[0033]

As described above, according to the present invention, the multiple
A nozzle plate with a number of nozzle openings
Each nozzle corresponds to the nozzle opening arranged on the plate.
The spacer member that partitions the opening and one of the spacer members.
A pressure generating member for sealing the surface, and
Constructed by sealing both sides of spacer members with a slip plate
The pressure generating chamber is pressurized by the pressure generating member,
Inkjet recording that ejects ink droplets from the opening
In the head, the pressure generating chamber is
The first perpendicular to the crystal orientation (110) plane of the silicon surface
Approximately 35 degrees to the (111) plane and the (110) plane of the surface
And a second (111) plane having an inclination of
Nozzle opening arrangement direction formed by the second (111) plane and
Since a part of the wall in the orthogonal direction is set to a thickness that can be deformed by pressure, the required compliance can be obtained regardless of the miniaturization of the pressure generating chamber accompanying the further increase in dot density. It is possible to obtain an inkjet recording head with stable ejection.

[Brief description of drawings]

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

2A and 2B are respectively a top view and a cross-sectional view showing an embodiment of a spacer member of the same apparatus.

FIG. 3 is a cross-sectional view that schematically shows the deformation that occurs in the wall when pressure is applied to the pressure generating chamber.

4A and 4B are a top view and a cross-sectional view of a spacer member showing another embodiment of the ink jet recording head of the present invention.

[Fig. 5] When pressure is applied to the pressure generating chamber of the above device,
It is sectional drawing which shows the deformation | transformation which a wall produces typically.

FIG. 6 is a cross-sectional view illustrating an etching process of a silicon base material of the ink jet recording head of the present invention.

FIG. 7 is a plan view for explaining the etching process of the silicon base material of the ink jet recording head of the present invention.

FIG. 8 is a diagram showing the direction on the surface of the silicon wafer of the (110) surface used in the inkjet print head of the present invention.

[Explanation of symbols]

1 nozzle plate 2 nozzle openings 3 Spacer members 4 Pressure generation chamber 5 supply ports 7 Second plate 8 walls 9 space 10 walls 13 walls 14 walls 31 Spacer member 41 Pressure generation chamber 101 First (111) plane 102 second (111) plane 104 recess

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (3)

(57) [Claims] And 1. A plurality of the nozzle plate in which the nozzle openings are column set, the nozzle openings arranged in nozzle plate
Correspondingly, a spacer member for partitioning each nozzle opening and the spacer
A pressure generating member for sealing one surface of the pacer member
The pressure generating member and the nozzle plate
A pressure generating chamber configured by sealing both sides of the pacer member,
Pressure is applied by the pressure generating member, and ink is ejected from the nozzle opening.
In the ink jet recording head for ejecting droplets, the pressure generating chamber is made of silicon in the spacer member.
The crystal orientation of the surface is the first (11) orthogonal to the (110) plane.
1) plane and about 35 degrees with respect to the (110) plane of the surface.
Nozzle opening arrangement direction defined by the second (111) plane having an inclination and formed by the second (111) plane
An ink jet recording head characterized in that a part of a wall in a direction orthogonal to is set to a thickness that can be deformed by pressure. 2. The pressure generating chamber is provided with the second (11
1) having two faces, each of which has a second (111) face
Each part of the formed wall has a thickness that can be deformed by the pressure.
2. The ink jet recording head according to claim 1, wherein the ink jet recording head is set only for the purpose. 3. The silicon surface of the spacer member
By anisotropic etching from the surface of the nozzle plate,
The second recess is formed in the direction orthogonal to the nozzle opening arrangement direction.
The ink jet recording head according to claim 1, wherein the ink jet recording head is formed so as to face a wall formed by the (111) plane .