JP2976626B2 - Droplet ejector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid droplet ejecting apparatus.

[0002]

2. Description of the Related Art Conventionally, ink jet printers such as a bubble jet type using an electrothermal conversion element as a pressure generator and a piezoelectric type using an electromechanical conversion element have lower noise than an impact type printer. For some reason, it has attracted attention in recent years. For example, in the case of a piezoelectric type, the volume of the ink flow path is changed by the dimensional displacement of the piezoelectric actuator, so that the ink in the ink flow path is ejected from the orifice when the volume is reduced, and the ink flow is transmitted from the other valve when the volume is increased. The ink is introduced into the device, and is called a drop-on-demand system. Then, by arranging a large number of such ejecting devices close to each other and ejecting ink from the ejecting device at a predetermined position, desired characters and images are formed.

An example of this type of droplet ejecting apparatus will be described with reference to FIGS.

[0004] The lid 58 is joined to the piezoelectric ceramic plate 52 having a plurality of parallel side walls 55 a to 55 f and polarized in the direction of arrow 128 via an adhesive layer (not shown), so that A large number of parallel ink flow paths 54a to 54e having an interval from each other are formed. The ink passages 54a to 54e are long and narrow with a rectangular cross section, and the side walls 55a to 55f extend over the entire length of the passage and can be deformed perpendicularly to the passage axis to change the ink pressure in the passage. Drive electrodes 57a to 57g for applying a drive electric field are formed on the surfaces of the side walls 55a to 55f.

When the ejection device 84c is selected in the array 101 according to predetermined print data as shown in FIG. 9, for example, the driving electrodes 57c and 57e and the driving electrodes 57d
During this time, a driving electric field is applied. At this time, since the direction of the driving electric field (the direction of the arrow in the figure) is orthogonal to the direction of polarization, the side walls 55c and 55d are deformed in a C-shape in the ink flow path 54c due to the piezoelectric thickness-shear effect. Due to this deformation, the ink pressure in the ink flow path 54c increases, and ink droplets are ejected from ejection ports (not shown).

[0006]

However, if an attempt is made to construct a printer head having an array of a plurality of rows in order to improve the printing speed in the above-described conventional droplet ejecting apparatus, an example of an assembling process is shown in FIG. As shown, sidewall 55
After joining a plurality of piezoelectric ceramic plates 52 having an ink flow path 54 composed of a number of grooves sandwiched between them and a lid 58 of the ink flow path 54, the ink flow path 54
The nozzle plate 110 in which the injection ports 112 corresponding to the piezoelectric ceramic plates 5 are formed one by one
2 and the lid 58 must be joined to the end face of the joined body,
The increase in the number of parts and the need for the same number of groove processing steps as the number of the injection ports 112 required problems, such as a low yield and an increase in manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a large number of jetting devices with a small number of groove processing steps and a small number of parts, a low production cost and a high yield, and a high yield type liquid. It is an object to provide a droplet ejection device.

[0008]

According to a first aspect of the present invention, there is provided a droplet ejecting apparatus comprising a plurality of ink flow paths formed of piezoelectric ceramics and sandwiched between first side walls. have a direction of intersecting grooves in said ink flow path
A plate formed by dividing the first side wall into a plurality of parts, a second side wall intersecting the ink flow path and separating each ink flow path into a plurality of ink chambers, and the ink chamber
Cover, an injection port communicating one-to-one to the ink chamber Yes Sulf
And data, by deforming the plate, changing the volume of the ink chamber, and a driving means for ejecting ink from ejection port of the lid.

[0009] A droplet ejecting apparatus according to claim 2 of the present invention.
Defines a plurality of ink flow paths sandwiched between the first side walls.
And a plate having
A second side wall separating the ink flow path into a plurality of ink chambers;
An ejection port that communicates with the ink chamber on a one-to-one basis;
A lid joined to the plate and an ink chamber;
Pressure on the ink to eject ink from the ejection port of the lid
And a driving unit for driving.

[0010]

According to the first aspect of the present invention having the above configuration, the first side for forming a plurality of ink flow paths is provided.
The first wall is formed by a groove in a direction intersecting the ink flow path.
The side wall is divided into a plurality of parts, and the ink flow is
The path is divided into a plurality of ink chambers, and one-to-one
By providing a jet port that passes through the lid, each ink chamber
Due to the deformation of the corresponding piezoelectric ceramic plate,
A droplet ejector that ejects ink from several rows of ejectors
Can be provided.

According to a second aspect of the present invention, there is provided a liquid droplet ejecting apparatus.
A plurality of ink flow paths on the plate intersect with the ink flow paths.
The second side wall is formed on the lid, and the lid is
To separate each ink channel into multiple ink chambers.
And eject the ink jets communicating with the ink chambers one-to-one.
By providing, a droplet ejection device having a plurality of rows of ejection ports
Can be provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, a part of the array 1 is cut away, and a plurality of parallel
A piezoelectric ceramic plate 2 having an ink flow path 4 interposed between the side walls 5 of the ink supply path and an ink supply path 3 composed of two grooves orthogonal to the ink flow path 4; The second side wall 9 which engages with the groove 3 and the lid 8 having the injection port 12 are joined to each other.

FIG. 2 is a cross-sectional view of the array 1, wherein each of the ink flow paths 4 is divided into three ink chambers 6 by a second side wall 9, and the ejection ports 12 are provided one-to-one with the ink chambers 6. Is supported. A gap is provided at the bottom of the ink supply path 3 at an engagement portion between the ink supply path 3 and the second side wall, and this gap communicates with an ink supply section (not shown).

FIG. 3 is a longitudinal sectional view of the array 1. The array 1 is subjected to polarization processing in the direction of arrow 28, and has ink chambers 6a, 6b, 6c, 6d formed of four parallel grooves, and five first side walls 5a, 5b sandwiching the ink chamber 6. 5c, 5
and a lid 8 having ejection ports 12a to 12d corresponding to the ink chambers 6a, 6b, 6c and 6d on a one-to-one basis. Further, the ejection device including the ink chamber 6a and the ejection port 12a is
4a, and the other injection devices are similarly injection devices 34b and 34.
c and 34d.

The piezoelectric ceramic plate 2 is prepared by subjecting a lead zirconate titanate (PZT) -based ceramic material having ferroelectricity to a polarization treatment in the direction of arrow 28, as shown in FIG. The grooves forming the parallel ink flow paths 4 having the formed shapes are cut by a required number by rotation of a diamond cutting disk or laser or the like, and an electrode 7 is formed on the surface of the groove side portion, as shown in FIG. It is obtained by cutting a groove forming the ink supply path 3 in a direction orthogonal to the ink flow path 4 by rotating a diamond cutting disk or by using a laser or the like.

As shown in FIG. 7, for the lid 8, a plate made of the same kind of material as the piezoelectric ceramics plate 2 not subjected to polarization processing or another material is prepared, and a plurality of parallel grooves are formed by the above-described method. A second side wall 9 is formed to divide each of the ink flow paths 4 into three ink chambers 6, and a lead electrode 11 for applying a driving electric field is formed on the surface of the second side wall 9. Injection ports 12 corresponding one-to-one with chamber 6
Can be obtained by processing the hole with laser or etching. Then, the array 1 is obtained by joining the piezoelectric ceramic plate 2 and the lid 8 such that the groove forming the ink supply path 3 and the second side wall 9 are engaged with each other.

The array 1 is provided with electric circuits as shown in FIG. In this electric circuit, the electrodes 7 a to 7 f are separately connected to the LSI chip 16 via the lead electrodes 11, respectively.
Data line 20, voltage line 22, and ground line 2
4 is also connected to the LSI chip 16.

The first ink chambers 6a to 6d are not adjacent to each other.
The clock line 18 is divided into a second group.
Successive clock pulses supplied from the first and second groups continuously drive the first and second groups. The data in the form of multi-bit words appearing on the data line 20 determines which of the ink chambers 6a to 6d of each group should be activated, and the electrodes of the ink chambers 6 of the group selected by the circuit of the LSI chip 16. The voltage V of the voltage line 22 is applied to 7a to 7f. The first side walls 5a to 5e on both sides of the ink chambers 6a to 6d selected by this voltage are deformed by the piezoelectric effect, and therefore all the ink chambers 6 in each group are deformed.
a to 6d become operable. At this time, the electrodes 7a to 7f of the inactive ink chambers 6a to 6d of the same group and the electrodes 7a to 7f of all the ink chambers 6a to 6d belonging to the other groups are grounded.

Next, the operation will be described.

FIG. 4 shows a case where the ejection device 34b is selected in accordance with predetermined print data.
The voltage V of the voltage line 22 is applied to the inner electrode 7c, and the other electrodes 7a, 7b, 7d, 7e, 7f are grounded. Since an electric field (in the direction of the arrow in the figure) perpendicular to the polarization direction is applied to the first side walls 5b and 5c, the first side walls 5b and 5c are formed in a C-shape by the deformation of the piezoelectric thickness-shear effect. Deforms inward. Therefore, the ink chamber 6
b, the ink in the ink chamber 6b is
Injected through 2b. Further, when the application of the voltage is cut off and the first side walls 5b, 5c are returned to the original positions, the ink supply unit 3 (see FIG. 2) moves from the ink supply unit (not shown) with the increase in the volume of the ink chamber 6b at that time. Is replenished via the ink. For example, when another ejection device 34c is selected, the first side walls 5c and 5d are deformed, and the ink in the ink chamber 6c is ejected.

As is clear from the above description,
The droplet ejecting apparatus of the present embodiment has the same number of ink passages as the number of ejecting apparatuses and the number of parts and the groove machining process as compared with the conventional droplet ejecting apparatus that required joining a plurality of piezoelectric ceramic plates. , The yield during manufacturing is good, and the manufacturing cost can be reduced.

The present invention is not limited to the embodiment described in detail above, and can be modified without departing from the scope of the invention.

[0024]

As is apparent from the above description, according to the present invention, a plurality of rows can be formed with a small number of grooves and a small number of parts.
It is possible to provide a high-speed printing type droplet ejecting apparatus having an ejection port , low manufacturing cost, and high yield.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an array with a part cut away.

FIG. 2 is a cross-sectional view of the array.

FIG. 3 is a longitudinal sectional view of an array.

FIG. 4 is an explanatory diagram showing a state in which an electric circuit is provided in the array and is driven.

FIG. 5 is a perspective view in which grooves and electrodes are formed on a piezoelectric ceramic plate.

FIG. 6 is a perspective view of the piezoelectric ceramic plate further processed in a direction perpendicular to the groove.

FIG. 7 is a perspective view of the lid as viewed from below.

FIG. 8 is a cross-sectional view of a conventional array.

FIG. 9 is an explanatory diagram showing a state in which an electric circuit is provided in a conventional array and is driven.

FIG. 10 is a perspective view showing an assembled state of a conventional liquid droplet ejecting apparatus having a plurality of rows of arrays.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Array 2 Piezoelectric ceramic plate 4 Ink channel 5 1st side wall 6 Ink chamber 8 Lid 9 2nd side wall

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-290257 (JP, A) JP-A-3-243357 (JP, A) JP-A-2-8059 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B41J 2/045 B41J 2/055

Claims (2)

(57) [Claims] 1. A droplet ejection apparatus having a large number of injectors for injecting Lee ink of the ink flow path with a pressure generator, a piezoelectric ceramics, a plurality of ink flow comprising sandwiched by the first side wall It has a road, crossing the ink flow path
A plate formed by dividing the first side wall into a plurality of grooves by a direction groove; and a second side wall intersecting the ink flow path and separating each of the ink flow paths into a plurality of ink chambers. When, covering the ink chamber, a lid which have a jetting port communicating one-to-one to the ink chamber, the plate is deformed to vary the volume of the ink chamber, the ink from the ejection port of the lid ejection And a driving unit for driving the droplet. 2. The method of claim 1, wherein the pressure generating member is used to form an ink in an ink flow path.
Droplet ejection device equipped with a large number of ejection devices that eject liquid
hand, Has a plurality of ink flow paths sandwiched by the first side wall
Plate Intersects the ink flow path, and connects each of the ink flow paths to a plurality of
A second side wall separating the ink chamber, and a one-to-one connection with the ink chamber;
Having an injection port communicating with the plate, and joining on the plate
And the lid Pressure is applied to the ink in the ink chamber, and the ink is ejected from the lid.
Drive means for ejecting ink from the mouth.
Droplet ejection device.