JP3634555B2 - Inkjet recording head - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to an ink jet recording head provided with a flexible piezoelectric vibrator corresponding to a pressure generating chamber communicating with a nozzle opening and compressing the pressure generating chamber with the piezoelectric vibrator to generate ink droplets, and more specifically, an ink container The present invention relates to a structure of a reservoir that supplies the ink in the pressure generating chamber.
[0002]
[Prior art]
Inkjet recording heads that generate ink droplets by providing a piezoelectric diaphragm in a partial area of the elastic plate that constitutes the pressure generating chamber and changing the volume of the pressure generating chamber by the deflection displacement of the piezoelectric diaphragm Since the large area of the chamber can be displaced, the ink droplets can be stably generated.
[0003]
Such a recording head has a piezoelectric vibration plate on its surface and forms an oscillating member, a spacer that forms a pressure generating chamber, and the other surface of the spacer is sealed, and the pressure generating chamber and the ink supply port A lid member having a communication hole for connecting the pressure generation chamber, a communication hole for connecting the pressure generation chamber and the nozzle opening, and one surface is sealed by the lid member, and communicates with each pressure generation chamber via the ink supply port. A reservoir, a reservoir forming plate provided with a communication hole connecting the nozzle opening and the pressure generating chamber, and a nozzle plate provided with a nozzle opening for sealing the other surface of the reservoir forming plate, respectively. Are integrally formed.
[0004]
Such an ink jet recording head quickly replenishes the amount of ink consumed in the pressure generating chamber and suppresses the rise in the pressure of the reservoir after ink droplet ejection, so that the reservoir has a sufficient volume. It is secured.
For this reason, the reservoir C is connected to an external ink container via the ink inlet D as shown in FIG. 3, and in particular, ink is supplied to the pressure generating chambers E, E, E arranged in a plurality of rows. In the case of supplying the ink, there is a problem that the ink tends to stagnate because the flow velocity of the ink at the branch portions F and F is low, and the bubbles are likely to stagnate in this region.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of these problems, and an object of the present invention is to provide an ink jet recording head in which the flow rate of ink in the vicinity of the ink inlet is increased to improve the elimination of bubbles in the entire reservoir. Is to provide.
[0006]
[Means for Solving the Problems]
In order to solve such a problem, in the present invention, a pressure generating chamber having a pressure generating member, an ink supply port for supplying ink to the pressure generating chamber, and the pressure generating chamber communicate with the pressure generating chamber via the ink supply port. In an ink jet recording head comprising a reservoir and an ink introduction port connected to an external ink container to supply ink to the reservoir, the reservoir is substantially U-shaped through a branch portion in the vicinity of the ink introduction port. It is branched into Jo, the depth of the bifurcation, characterized in that shallow than the formation region of the ink supply port.
As a result, the ink flow velocity in the vicinity of the ink introduction port where the bubbles are likely to stagnate is higher than that of the reservoir body , and the bubble elimination is improved.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Therefore, details of the present invention will be described below based on the illustrated embodiment.
1, 2, and 3 are an exploded perspective view showing an embodiment of the present invention and a cross-sectional view showing a structure in the vicinity of a pressure generating chamber connected to one reservoir, where reference numeral 1 denotes In the pressure generating unit, a thickness suitable for forming the pressure generating chamber, for example, 150 μm zirconia (ZrO ₂ ) ceramic plate such as pressure generating chambers _{2, 2, 2} ,. The perforated spacer 3, the first lid 4 that is elastically deformable made of a thin zirconia plate having a thickness of about 10 μm on one surface thereof, the pressure generating chamber 2 as a nozzle opening 5 and an ink supply port 6 A piezoelectric element made of PZT is formed by sealing with a second lid body 9 having communication holes 7 and 8 connected to the first lid body 4 and facing the common electrode 10 and the pressure generating chamber on the surface of the first lid body 4. The vibrating body 11 is formed, and the volume of the pressure generating chamber 2 is expanded and contracted by a driving signal. It is configured to.
[0008]
Reference numeral 12 in the figure is a flow path unit, and a plurality of reservoirs 13 having a substantially “U” shape so that ink can be supplied to two rows of pressure generating chambers, three in this embodiment, are formed at a constant pitch. The reservoir forming substrate 15 provided with the communication hole 14 communicating with the end region on the center side of the pressure generating chamber 2 is communicated with the region 13b where the branching portions 13a and 13a of the reservoir 13 merge on one surface. The ink supply port forming substrate 18 in which the ink introduction port 16, the ink supply port 6, and the nozzle communication hole 17 are formed, and the other surface communicates with the pressure generating chamber 2 through the nozzle communication holes 7, 17, and 14. It is configured to be sealed by a nozzle plate 19 having a nozzle opening 5 to be sealed.
[0009]
By fixing a plurality of pressure generating units 1 on the surface of the flow path forming unit 12, the pressure generating chamber 2 is supplied with ink from the reservoir 13 of the flow path unit 12 and is pressurized in the pressure generating chamber 2. The recording head functions as a recording head that discharges the ink as ink droplets from the nozzle opening 5 through the nozzle communication holes 7, 17, and 14.
[0010]
In the reservoir forming substrate 15, a step 13 c is formed so that the depth d 1 of the branch region near the ink inlet 16 is shallower than the depth d 2 of the region communicating with the ink supply port 6. Further, at least the region of the reservoir main body where the ink supply port 6 is formed has a recess 13d formed on the side facing the nozzle plate 19, and is configured to be elastically deformable. In the figure, reference numeral 13e denotes a through hole communicating with the ink introduction port 16.
[0011]
According to this embodiment, when the ink introduction port 16 is connected to an external ink cartridge or the like by a flow path, the nozzle opening 5 is sealed by the capping means, and negative pressure is applied from the suction pump, the ink in the cartridge is transferred to the ink introduction port. 16, flows into the reservoir 13 from the through-hole 13e, passes through the pressure generating chamber 2 through the ink supply port 6, and is discharged from the nozzle opening 5 to the capping means to fill the recording head with ink. .
[0012]
In the course of ink charging, ink introduction port 16 near the bifurcation region 13a, since 13a has its depth d1 shallow, wherein the ink flows through a large flow rate, bubble, etc. This is reservoir - ink Bas 13 supply port 6 And flow into the area opposite. Then, it flows into the pressure generating chamber 2 from any one of the ink supply ports 6 that are distributed in the longitudinal direction and located above, and is discharged together with the ink to the capping means.
[0013]
In this way, when the ink filling is completed, when the drive signal is applied to the piezoelectric vibrator 11 to reduce the volume of the pressure generating chamber 2, the ink in the pressure generating chamber 2 is pressurized, and a part of the nozzles are nozzles. The ink flows into the nozzle opening 5 through the communication holes 7, 17, and 14 and is ejected as ink droplets. Some ink flows backward from the ink supply port 6 to the reservoir 13. Although the pressure of the reservoir 13 tends to increase due to the reverse flow, the nozzle plate side in the region where the ink supply port 6 is formed is elastically deformed to absorb the pressure increase as much as possible and a drive signal is applied. The pressure fluctuation of the pressure generating chamber 2 that is not in use is prevented. As a result, it is possible to prevent the occurrence of so-called crosstalk in which minute ink droplets are ejected from the nozzle openings 5 to which no drive signal is applied.
[0014]
Such a reservoir forming substrate 14 can be formed by etching both surfaces of a single metal plate 15a, 15b, or by pressing to form a recess or a through hole and laminating. it can.
[0015]
【The invention's effect】
As described above, according to the present invention, it is possible to increase the ink flow velocity in the vicinity of the ink introduction port where the bubbles are likely to stagnate , thereby improving the elimination of bubbles .
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an embodiment of the present invention.
FIGS. 2A and 2B are diagrams showing an embodiment of an ink jet recording head according to the present invention in cross-sectional structures taken along lines AA and BB, respectively.
FIG. 3 is a diagram illustrating a positional relationship between a reservoir of an ink jet recording head and an ink introduction port.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressure generating unit 2 Pressure generating chamber 3 Spacer 4 1st cover body 5 Nozzle opening 6 Ink supply port 7, 8 Communication hole 9 2nd cover body 11 Piezoelectric vibrator 12 Flow path unit 13 Reservoir 13a, 13a Branch Part 13c Step 13d Recess 15 Reservoir forming substrate 16 Ink introduction port 19 Nozzle plate

Claims (3)

A pressure generating chamber having a pressure generating member; an ink supply port for supplying ink to the pressure generating chamber; a reservoir communicating with the pressure generating chamber via the ink supply port; an ink connected to an external ink container; In an ink jet recording head comprising an ink inlet for supplying
The reservoir - server may be branched in a substantially U-shaped through a bifurcation in the vicinity of the ink introduction port, an ink jet in which the depth of the branch portions is equal to or shallower than the formation region of the ink supply port Recording head. An elastic plate having a piezoelectric vibration plate on its surface to form a vibration member;
A spacer whose one surface is sealed by the elastic plate to form a pressure generating chamber;
A lid member that seals the other of the spacers and includes a communication hole communicating at both ends of the pressure generating chamber;
An ink supply port forming substrate comprising: an ink supply port that imparts flow resistance to the ink supply path to the pressure generation chamber; a communication hole that communicates with the pressure generation chamber; and an ink introduction port that communicates with an external ink container ,
A reservoir forming plate comprising: a reservoir communicating with each of the pressure generating chambers via the ink supply port; and a communicating hole communicating with the pressure generating chamber;
A nozzle plate having a nozzle opening that seals the other surface of the reservoir forming plate and is connected to the pressure generation chamber through one of the communication holes of the reservoir forming plate and the lid member;
In an ink jet recording head formed by integrally laminating each in order,
The ink jet type wherein the reservoir is branched in a substantially U shape through a branching portion in the vicinity of the ink introduction port, and the depth of the branching portion is shallower than the formation region of the ink supply port. Recording head. The nozzle plate side of the region where the ink supply port of the reservoir forming substrate is formed is configured to be elastically deformable by the pressure of ink flowing backward from the pressure generating chamber during ink droplet ejection. 2. An ink jet recording head according to 2.

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