JPH07195685A - Recording head for inkjet printer - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent bubbles mixed in the ink from staying in the ink flow path. [Structure] The through holes 6, 10, 14 formed in the plates 4, 8, 12 so as to connect the pressure chamber 17 and the nozzle 2 are
By locating the tip of the pressure chamber 17 in a staggered manner from the tip to the outside, the flow path of the ink from the pressure chamber 17 to the nozzle 2 is gently curved so that the ink flow is smooth and mixed in the ink. This prevents bubbles from staying in the flow path.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, a recording head for an ink jet printer using a piezoelectric element is commonly used for each thin plate material in order to reduce the size thereof, as disclosed in, for example, Japanese Patent Laid-Open No. 4-366643. A so-called laminated type has been adopted in which an ink supply section, a pressure chamber, an ink flow path to a nozzle, and the like are formed, and these are sequentially laminated on the back surface of a nozzle plate.

In this type of recording head, not only the head itself can be made extremely small, but also the pressure chamber takes a large space, but the length of the ink flow path to the nozzle is short and uniform. Although it is possible to increase the recording speed, the fine air bubbles mixed in the ink may enter the corners of the flow path formed in each thin plate material and stay there, which may adversely affect the ink ejection performance. Have it.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to:
It is an object of the present invention to provide a new laminated recording head capable of suppressing the retention of air bubbles in the ink flow path as much as possible.

[0005]

That is, according to the present invention, as a recording head for a laminated type ink jet printer for achieving such a problem, a through hole formed in each thin plate material so as to connect a pressure chamber and a nozzle. Are sequentially shifted outward from the nozzle side tip of the pressure chamber, and the flow path of the ink from the pressure chamber to the nozzle is made into a smooth curved shape,
This is to prevent bubbles in the ink from staying in the corners.

[0006]

Embodiments Now, the embodiments shown in the drawings will be described. FIG. 1 is a sectional view of a recording head according to an embodiment of the present invention, FIG. 2 is a rear view of the recording head with a diaphragm removed, and FIG. 3 is a series of ink flow paths. It is the figure shown about.

First, the laminated structure of the laminated recording head will be described. The nozzle plate 1 having a large number of nozzles 2 formed therein is made of stainless steel having corrosion resistance, and the back surface of the nozzle plate 1 is also made of a thin plate of stainless steel. The formed spacer 4, that is, the first thin plate material is the adhesive 3
Are integrally laminated with.

A reservoir chamber 5 communicating with an ink supply tank (not shown) is bored in the spacer 4 along the arrangement direction of the nozzles 2, and the position of the nozzles 2 is larger than the hole diameter of the nozzles 2. A first through hole 6 having a diameter is formed.

On the back surface of the spacer 4, an ink supply plate 8 made of stainless steel, that is, a second
Is attached with an adhesive 7, and an orifice 9 communicating with the reservoir chamber 5 and a second through hole 10 communicating with the first through hole 6 are formed therein.

On the other hand, the reinforcing plate 12, which is attached to the back surface of the ink supply plate 8 with the adhesive 11, that is, the third thin plate member, together with the pressure chamber plate 16 laminated on the back surface, that is, the fourth thin plate member. The pressure chamber plate 1 is integrally formed of a sintered material such as zirconia.
The partition walls 18 for partitioning the pressure chambers 17 of 6 are provided with a function of suppressing outward deformation due to flexural deformation of the piezoelectric vibrator 20 in the width direction.

The reinforcing plate 12 is provided with an orifice 9
And an ink supply hole 13 that connects the pressure chamber 17 with the pressure chamber 17.
And a third through hole 14 that connects the second through hole 10 with
Further, the pressure chamber plate 16 is formed with a pressure chamber 17 having a size capable of ejecting an ink droplet having a required particle diameter from the displacement amount of the piezoelectric vibrator 20, one end of which is the above-mentioned ink supply. The other end of the hole 13 communicates with a third through hole 14 reaching the nozzle 2.

Further, on the back surface of the pressure chamber plate 16, a thin vibration plate 19 made of zirconia or the like having a high elastic modulus is integrally laminated so as to cover the pressure chamber 17, and piezoelectric vibration is further provided on the back surface thereof. The child 20 is integrally attached.

Next, the ink flow path configuration, which is the main part of the present invention, will be described. The ink flow path from the pressure chamber 17 to the nozzle 2 is the first through hole 6 on the spacer 4.
As can be seen in FIG. 3, the second through hole 10 on the ink supply plate 8, the third through hole 14 on the reinforcing plate 12, and the nozzle tip 17a of the pressure chamber 17,
It is configured to form a large arc so that the ink smoothly flows from the horizontal direction to the vertical direction from the pressure chamber 17 located on the back side of the recording head main body toward the nozzle 2 on the front side.

That is, the through holes 6, 10 and 14 of the spacer 4, the ink supply plate 8 and the reinforcing plate 12 are formed as holes having substantially the same diameter, and the first through hole 6 serves as the axis of the nozzle 2. The second through hole 10 and the nozzle side tip portion 17a of the pressure chamber 17 are positioned so as to coincide with each other, the axis of the second through hole 10 is closer to the reservoir chamber 5 side than the axis of the third through hole 14, and The through holes 14, 10 and 6 continuing to the pressure chamber 17 side are positioned on the reservoir chamber 5 side with respect to the axial center of the nozzle 14 so that the nozzle side tip portion 17 of the pressure chamber 17 is formed.
It is configured to be located in order from a to the outside.

Further, in this embodiment, the axis of the ink supply hole 13 provided in the reinforcing plate 12 is positioned so as to coincide with the axis of the Ophilith 9, and the pressure chamber 17 communicating with the ink supply hole 13 is formed. The orifice-side rear end portion 17b is shifted toward the nozzle side from the axis of the ink supply hole 13, in other words, the ink supply hole 13 is moved to the pressure chamber 17.
The ink is configured to flow from the orifice 9 into the pressure chamber 17 in a gentle curve by being slid outward from the orifice-side tip portion 17b.

With the above-mentioned structure, the pressure chamber 1
The flow of ink from 7 to the nozzle 2 and the flow of ink from the orifice 9 to the pressure chamber 17 have a gentle curved shape as shown by the arrow in FIG. By removing the stagnation part as much as possible, the bubbles mixed in the ink are discharged without staying in the flow path.

FIG. 4 shows another embodiment of the present invention relating to a recording head laid out based on the above-mentioned ink flow path structure.

Nozzle channel unit 3 in this embodiment
No. 0 is positioned such that the axial centers of the through holes 6, 10, 14 communicating with the nozzle 2 are shifted outward from the nozzle-side tip of the pressure chamber 17, and the nozzle 2 and the nozzle of each adjacent nozzle channel unit 30 are 2 and the other nozzle channel unit 3
The nozzles 0 are arranged so as to face each other in a staggered manner so that the nozzles 2 of 0 enter, and by arranging in this way, all the nozzles 2 ... Are arranged on the same line LL.

In this embodiment, by arranging the through holes 6, 10, and 14 outside the tip of the pressure chamber 17, the arrangement pitch P of the nozzles 2 ... Determined by the width W of the pressure chamber 17. The other nozzles 2, ... Can be positioned in between to double the array density.

Further, in FIG. 5, the pressure plate 16, that is, the pressure chambers formed in the fourth thin plate member is not changed in arrangement and the like. 3 shows an embodiment of the present invention in which the nozzles 2 can be made to communicate with each other.

That is, as shown in FIGS. 5 (a) and 5 (b), this device changes the positions of the through holes 6, 10, 14 formed in each thin plate material of the spacer 4, the supply plate 8 and the reinforcing plate 12. In this way, the pressure chambers 17 formed on the common pressure chamber plate 16 can be communicated with the nozzles on the color image forming nozzle plate and the monochrome image forming nozzle plate which are arranged at different positions. To configure
The manufacturing cost is reduced.

This is a line connecting the centers of the through holes 6, 10, 14 formed in the thin plate members 4, 8, 12 with the center of the ink supply side tip portion 17a of the pressure chamber 17 and the center of the nozzle 2. By locating it on AA, it is possible to eject ink droplets under certain conditions without causing stagnation of ink, even if the nozzle is not located on the longitudinal axis of the pressure chamber. .

Further, in each of the above-mentioned embodiments, the thin plate member 4,
Although the through holes 6, 10 and 14 on the holes 8 and 12 have substantially the same diameter, as shown in FIG.
It is also possible to form the diameters of 0 and 14 so that they become smaller toward the nozzle 2, and by forming in this way, stagnation of ink and retention of bubbles can be further reduced.

[0024]

As described above, according to the present invention, the through holes formed in each thin plate material so as to connect the pressure chamber and the nozzle to each other are positioned so as to be shifted in order from the tip of the pressure chamber to the outside. Therefore, the ink flow path from the pressure chamber to the nozzle can be formed as a gentle curve that does not cause stagnation of the ink, which makes the flow of ink smooth and allows the retention of bubbles mixed in the ink. By suppressing as much as possible, it is possible to maintain good ink droplet ejection performance for a long time.

Moreover, by alternately arranging the nozzle flow path units thus configured so as to face each other, it becomes possible to eliminate the restriction of the width of the pressure chambers and to double the nozzle arrangement density, thus improving the print quality. Higher images can be realized by a simpler control mechanism.

[Brief description of drawings]

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

FIG. 2 is a plan view of the same recording head as that shown without the diaphragm.

FIG. 3 is a perspective view showing an ink through hole portion of the same recording head.

FIG. 4 is a plan view showing another embodiment of the present invention.

5 (a) and 5 (b) are diagrams showing still another embodiment of the ink through hole portion.

[Explanation of symbols]

 1 Nozzle Plate 2 Nozzle 5 Reservoir Chamber 6, 10, 14 Through Hole 9 Orifice 13 Ink Supply Hole 17 Pressure Chamber 19 Vibration Plate 20 Piezoelectric Vibrator

Claims (4)

[Claims] 1. A recording head for an ink jet printer, comprising a plurality of thin plate members, each of which is formed with a series of ink flow paths partially extending from an ink supply section to a nozzle and then to a nozzle. A recording head for an ink jet printer, characterized in that respective through holes formed in each of the thin plate members so as to connect the nozzle and the nozzle are sequentially shifted outward from the tip of the pressure chamber on the nozzle side. 2. The through holes formed in each of the thin plate members so as to connect the pressure chambers and the nozzles are located on the line connecting the center of the nozzle-side tip of the pressure chambers and the nozzles. The recording head for an ink jet printer according to claim 1, wherein the pressure chamber is positioned so as to be shifted outward from the nozzle-side tip of the pressure chamber. 3. The opening area of a through hole formed in each of the thin plate members so as to connect the pressure chamber and the nozzle is reduced in order from the pressure chamber to the nozzle. Recording head for inkjet printers. 4. A recording head for an ink jet printer, which is formed by stacking a plurality of thin plate members partially forming a series of ink flow paths from an ink supply unit to a nozzle to a nozzle, Each through hole connecting the nozzles, each ink flow path unit that is positioned to be shifted outward from the nozzle side tip of the pressure chamber in order,
A recording head for an inkjet printer, characterized in that nozzles of one of the units are arranged so as to alternately face each other so as to be located between nozzles of the other unit.