JPH11300953A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform high speed printing by arranging one array of nozzles while shifting by half pitch from the other array and conducting the nozzles individually, and providing an ink chamber, an ink reservoir and an ink ejection drive element depending on the pitch thereby suppressing vibration being transmitted to a liquid in the ink liquid section of an adjacent nozzle. SOLUTION: The ink jet head comprises a plate 1 integrating a nozzle plate and an ink chamber plate, an oscillatory member 2, and a housing 6. Piezoelectric elements 4 are bonded to a substrate 10 in one and one correspondence to nozzles and an electrode 5 is bonded to the element 4. It is then spin coated with phenol resin fused into a solvent, applied with adhesive by silk printing, or the like, and hot pressed. The piezoelectric element 4 is applied with adhesive and jointed integrally with the oscillatory member 2 through fusion. Since phenol resin is employed entirely except the element 4, coefficient at thermal expansion of an ink jet head structure is made constant and sealing performance is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ink jet head.

[0002]

2. Description of the Related Art An ink-jet head discharges a small amount of ink droplets of 10 pl to 100 pl and is suitable for high-density printing.

The prior art is disclosed in Japanese Patent Application Laid-Open No. 55-867.
As disclosed in Japanese Patent Publication No. 67, the ink supply portion is formed as a common pool, and the ink chamber directly connected to each nozzle is directly connected to the pool to take in ink. .

For this reason, when one nozzle discharges an ink droplet, the vibration accompanying the discharge of the ink droplet is transmitted to the adjacent nozzle, which has an adverse effect on the discharge stability. Therefore, until the behavior of the previously driven ink nozzle becomes stable, the next nozzle cannot be driven, and the overall driving frequency is reduced. I was

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejecting apparatus in which the ink jet head performs a discharging operation and the ink drops of an adjacent nozzle are generated when an ink droplet pops out. The goal is to minimize vibration.

Further, even if the structure of the ink chamber is thin, a structure having as many joints as possible is used to increase the natural frequency of the structure of the ink chamber to provide a stable head.

By solving these problems, it is possible to discharge ink at a high frequency.

[0008]

According to the present invention for solving the above problems, a plurality of nozzles arranged in such a manner that the nozzle pitch of one row is shifted by half with respect to the nozzle pitch of the other row, and A plurality of ink chambers which are individually communicated and arranged so as to correspond to the nozzle pitch, a plurality of ink reservoirs which are communicated corresponding to each ink chamber, and an ink supply flow which is communicated with the ink reservoirs An ink-jet head is constituted by a path and a driving element for discharging ink which is mounted for each ink chamber.

Preferably, the ink chamber and the ink reservoir are arranged horizontally, and the ink supply channel is arranged vertically to the ink reservoir.

[0010] Further, by arranging the ink reservoirs in a line, the size can be reduced.

[0011]

FIG. 1 is an exploded perspective view of an ink jet head.

The ink jet head includes a plate 1 in which a nozzle plate and an ink chamber plate are integrally formed, a vibration member 2, and a housing 6.

The piezoelectric element 4 is bonded and fixed to a substrate 10. Moreover, the piezoelectric elements 4 are arranged so as to correspond one-to-one to the number of nozzles. The electrode 5 is joined to the piezoelectric element 4 and applies a voltage to the piezoelectric element 4.

FIG. 2 is a side sectional view of the ink jet head.

As shown in FIG. 2, the piezoelectric element 4 and the substrate 1
0, the housing 6, and the vibration member 2 are adhesively fixed.

Conventionally, this bonding method uses an epoxy resin for the piezoelectric element 4 and an adhesive having a better sealing effect than the epoxy resin for bonding other parts, and changes the adhesive in a narrow place for each purpose. Was. For this reason, the time required for joining and the complexity of the work also caused a work failure.

However, in the present invention, the vibration member 2, the housing 6, and the substrate 10 are made of phenol resin,
The bonding including the piezoelectric element 4 is performed.

Specifically, the adhesive 12 is applied to a thickness of about 3 to 30 microns by spin-coating a solution obtained by melting a phenol resin in a solvent or by applying an adhesive such as silk printing. Next, the objects to be bonded are joined by a method of pressing and heating and bonding.

As shown in FIG. 3, the bonding portion of the piezoelectric element is strongly bonded by bonding so that the adhesive 12 is bonded to the piezoelectric element 4 and is melted and integrated with the vibration member 2. Becomes

As described above, by unifying the parts other than the piezoelectric element with the same material with the phenol resin, the thermal expansion coefficient of the structure of the ink jet head can be made the same, so that the sealing performance with no peeling of the adhesive portion is good. Joining can be realized.

FIG. 4 is a perspective view showing a state in which the ink chambers 9 are separately mounted on the left and right sides (the vibration member 2 is removed).

9A, 9B, 9C are on the right side, 9a, 9b, 9
c is the left nozzle, 3A, 3B, 3C and 3 respectively
a, 3b, and 3c ink chambers.

The right head and the left head are shifted by half the pitch P, that is, P / 2. The ink reservoirs 8A, 8B, 8C, 8a, 8b, 8c supply ink to the respective ink chambers 3. The ink is supplied to the ink reservoir 8 from the ink flow path 7 individually.

The ink reservoirs 8 are arranged substantially in parallel with the ink chambers 9, and are arranged in a vertical line so that when ink enters from the ink flow path 7, each ink reservoir enters at a uniform head pressure.
It is possible to minimize the width.

When the interference due to mutual vibration when the ink droplet is ejected is large, as shown in FIG.
The nozzles are arranged in two rows on the left and right so that the ink reservoirs 8 are spaced apart from each other to prevent interference. Thereby, a margin can be provided so that the ink ejection can be performed faster.

FIG. 6 shows the ink chamber 3 and the ink reservoir 8 of the ink jet head viewed from the vibration member 2 side. When the ink is supplied from the ink reservoir 8, the opening of the restrictor portion 11 on the ink reservoir 8 side is formed at a predetermined angle θ so that the ink easily flows. Thereby, the ink chamber 3
In this state, the state where ink can rapidly flow and the next ink can be ejected can be quickly adjusted, so that high-speed printing can be performed. The predetermined angle θ which satisfies such a condition is set at 50 ° so as to reduce the head loss when ink enters.
It is preferable to set ° ≦ θ ≦ 120 °.

Note that the predetermined angle θ is 120 ° ≦ θ ≦ 18
In the case of 0 °, the ink can be quickly filled into the ink chamber 3 by adding R to the root of the connecting portion between the restrictor 11 and the ink reservoir 8 to reduce the head loss.

Further, as shown in FIG. 7, the restrictor unit 1 is so arranged as to reduce the head loss when the ink enters.
It is preferable that the cross-sectional area of the ink reservoir 8 in the vicinity of the connecting portion with the nozzle 1 gradually expands in the vertical direction.

Further, as shown in FIG. 7, the shape of the ink reservoir 8 near the opening of the restrictor portion 11 is such that when γ ≦ 60 °, the base of the ink reservoir 9 is rounded.

Alternatively, the restrictor unit 1 of the ink reservoir 8
As shown in FIG. 8, the shape near one opening is 60 ° ≦ γ.
When ≦ 120 ° (especially when the angle exceeds 90 °), it is preferable to provide the straight portion S so that the entrance is not narrowed.

[0031]

According to the above configuration, when ink is ejected, the influence of vibration on the adjacent ink chamber can be reduced. In addition, an ink reservoir is provided for each ink chamber so that ink is supplied, and since the relationship between the ink chamber and the flow path is at a right angle, the number of junctions between the ink chamber and the vibration film increases, resulting in a solid structure. Further, since the residual vibration after driving the piezoelectric element is rapidly attenuated and the driving system is stabilized, there is also an effect that high-speed driving becomes possible and high-speed printing becomes possible.

In addition, since the ink chambers have individual ink reservoirs, the rigidity of the ink chamber components increases, and the vibration after the head is driven is rapidly attenuated, so that the head can be driven immediately.

[Brief description of the drawings]

FIG. 1 Assembly drawing of an ink jet head

FIG. 2 is a cross-sectional view of an inkjet head.

FIG. 3 is a joining diagram of a piezo element part.

FIG. 4 is a perspective view of an ink chamber of the inkjet head.

FIG. 5 is a perspective view in which ink chambers and ink reservoirs are arranged in two rows.

FIG. 6 is a plan view as viewed from a vibration member of the inkjet head.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is a sectional view taken along line AA of another example of FIG. 6;

[Explanation of symbols]

1 is an ink chamber and nozzle integrated plate, 2 is a vibration member, 3 is an ink chamber, 4 is a piezoelectric element, 5 is an electrode, 6 is a housing, 7 is an ink flow path, 8 is an ink reservoir, 9 is a nozzle,
Reference numeral 10 denotes a substrate, and 11 denotes a restrictor.

Claims (6)

[Claims] 1. A plurality of nozzles arranged in such a manner that the nozzle pitch of one row is shifted by half from the nozzle pitch of the other row, and each of the nozzles is individually communicated and arranged so as to correspond to the nozzle pitch. A plurality of ink chambers, and a plurality of ink reservoirs communicated corresponding to each ink chamber,
An ink jet head comprising: an ink supply flow path connected to the ink reservoir; and an ink discharge drive element mounted for each ink chamber. 2. The ink jet head according to claim 1, wherein said ink chamber and said ink reservoir are arranged horizontally, and said ink supply flow path is arranged vertically to said ink reservoir. 3. The ink-jet head according to claim 1, wherein said ink reservoirs are arranged in one line. 4. The ink jet head according to claim 1, wherein a cross-sectional area of the ink reservoir near a connecting portion between the ink reservoir and the ink chamber gradually decreases toward the connecting portion. Inkjet head. 5. The ink jet head according to claim 4, wherein the angle θ of the opening of the ink reservoir at a portion connected to the ink chamber.
Is 50 ° to 120 °. 6. An ink jet head according to claim 4, wherein the angle θ of the opening of the ink reservoir at a portion connected to the ink chamber.
Is 120 ° to 180 °, and R is provided at the base between the ink reservoir and the restrictor.