JPH077164Y2 - Nozzle head of ink jet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement in the structure of a continuous jet nozzle head used in an inkjet printer.

[Prior Art] FIG. 8 shows the structure of a conventional general ink jet printer head, which has an excitation unit 3 including a back plate 1 and ultrasonic vibrations 2, and an ink chamber 4. It is composed of an acoustic focusing body 5 and a nozzle plate 7 having a nozzle 6. The nozzle plate 7 is formed separately from the body 5 by an electroforming process, an electric discharge process, or the like, and then joined by an adhesive material. The excitation unit 3 and the acoustic focusing body 5 are joined by screws 10 via a Teflon cover 8 and a Teflon backing 9.

[Problems to be Solved by the Invention] In this conventional device, as described above, the acoustic focusing body 5 and the nozzle plate 7 are separately processed, and they are later bonded with an adhesive. However, there is a problem that this bonding process is very difficult and costly. Because this bonding is not to mix the adhesive to the internal nozzle to withstand the vibration for shocking pressure and particle formation during ink ejection to withstand the Pressure 2-4 kg / cm ² with ink corrosion resistance This is because it is necessary to satisfy all difficult conditions such as not deforming or damaging the nozzle plate.

Further, the acoustic focusing body 5 has to be joined to the excitation part 3 with a large number of screws 10 through the packing 9 after forming the ink chamber 4 having a triangular cross section, and therefore, for manufacturing and assembling the head. There is also a problem that it takes time.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a nozzle head of an inkjet printer having a novel structure capable of manufacturing a nozzle head without performing a joining process of nozzle plates.

[Means for Solving the Problems] In the present invention, notches are formed intermittently or continuously in a part of the outer peripheral wall of the circular tube-shaped substrate along the axial direction thereof, and ink is provided in the notches. A plurality of nozzle holes for ejecting are formed, an ink is filled in the circular tube-shaped base material, and a vibrator for vibrating the ink is attached to the outer peripheral wall of the circular tube-shaped base material other than the cutout portion. I decided to do it.

[Operation] The ink filled in the cylindrical substrate is vibrated by the vibrator and ejected through the nozzle hole to be granulated.

According to this structure, since the nozzle holes are directly processed in the cylindrical base material, the joining process of the nozzle plates is omitted, and their mechanical strength is also increased.

[Embodiment] FIG. 1 shows an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA '.

In this embodiment, a circular pipe base material 20 made of stainless steel is used as an ink supply body, and a plurality of nozzle holes 21 are directly processed in the pipe base material 20 to form a multi-nozzle head. Since it is necessary to make the plate thickness of the nozzle portion 21 as thin as several μm, in this case, the concave portions 22 are separately provided in the plurality of nozzle portions.

In such a configuration, the inner diameter d ₁ of the pipe is vi: Ink sound velocity f; Particle frequency c; Correction coefficient n = 1, 2, 3, ... Close to 1, and the pipe 20 is used in a resonance state. In this example, vi = 1590 m / S, f = 240
KHz, c = 0.95, n = 1, pipe inner diameter d ₁ = 3.15m
m, nozzle diameter φ ₁ = 15 μm, plate thickness of nozzle part d ₂ = 5 μm,
The pipe thickness d ₃ = 0.1 mm, and the diameter of the recess 22 was d ₄ = 500 μm.

The configuration of the circular pipe base material 20 and the concave portion 22 is an important feature of the apparatus of this embodiment. That is, it is desirable that the nozzle portion plate thickness d ₂ is thin in terms of particle formation into ink droplets and nozzle processing conditions, but the portions other than the nozzle portion must be thick enough to withstand ink pressure, vibration, etc. Two contradictory conditions are achieved by providing the circular pipe 20 with the recess 22. Further, in this embodiment, since the bottom portion of the circular pipe 20 is formed to form a linear recess 22, the plate thickness of the nozzle portion 21 in this recess 22 is the thinnest as compared to the other portions, Therefore, even if the diameter of the recess is larger than about 100 μm used in the conventional apparatus (500 μm in this case), the strength of this portion can be sufficiently maintained. In addition, if the diameter of the recess 22 is large, ink may be ejected.
There is also an advantage that the recess 22 is not filled with ink at the time of stop and the cleaning is easy.

The multi-nozzle head having such a configuration can be manufactured by using, for example, an electric discharge machining technique.

Before performing electrical discharge machining, first, both ends of the stainless steel pipe are bent 90 degrees in opposite directions as shown in FIG. The pipe is positioned with respect to the electric discharge machine by using the 90 ° bent portion. For example, the pipe surface B shown in FIG. 1 is positioned vertically, and the pipe surface C is positioned horizontally. The pipe 20 is fixed to the electric discharge machine using these positioning surfaces, and thereafter, a plurality of recesses 22 having a minimum plate thickness of 5 μm are machined in this pipe. Then, it is replaced with one for an electrode nozzle of an electric discharge machine, and a nozzle 21 having a diameter of 15 μm is formed at each center of the recess 22.

Next, referring to FIG. 3, the ink supply tube 30 is connected to the pipe 20.
A configuration example in which the oscillator 40 and the oscillator 40 are provided will be shown. In this case, a flexible polymer oscillator is used as the oscillator 40, and the polymer oscillator 40 covers the outer peripheral surface of the pipe other than the nozzle 21. Although not shown in FIG. 3, the polymer vibrator 40 is covered with an insulating cover sheet.

According to this configuration, the vibrator 40 can be attached to all parts except the nozzle recess 22, so that the area of the vibrator can be increased and the vibration strength (vibration power) can be increased. You can Further, if the two vibrators 40 are stacked, the vibration power can be further increased.
Further, the configuration of FIG. 3 has another advantage that the vibration intensity in each nozzle portion 21 provided along the axial direction of the cylindrical pipe 20 can be made uniform. Because pipe 20
Since the cylindrical shape has a simple shape, the dimensional accuracy of the diameter is good, and therefore the pipe 20 vibrates simply in the radial direction. In other words, the resonance mode of the wave traveling in the axial direction of the pipe is extremely smaller in intensity than the resonance mode of the wave traveling in the radial direction of the pipe, so that the difference in the vibration intensity between the nozzles is so small that it can be ignored. . Further, in this case, since the oscillator 40 almost covers the peripheral surface of the pipe 20,
Radial vibration is more likely to occur, and since the vibrator is provided outside the ink chamber, there is no need for a short circuit due to ink.

FIG. 4 shows another embodiment of the present invention, in which a plurality of chip-shaped ceramic vibrators 50 are arranged side by side on a back plate 51 as a vibrator. As the ceramic vibrator 50, for example, zircon / lead titanate porcelain is used, and the back plate 51 is made of an elastic body so as to absorb vibrations of the vibrator 50 other than in the thickness direction.
The vibrator 50 and the pipe 20 are not adhered to each other, and only the back plate 51 presses them. This is because the pipe is vibrated only in the radial direction without transmitting vibration in the axial direction of the pipe.

FIG. 5 shows still another embodiment. In this case, a cylindrical ceramic vibrator 61 is provided on the cylindrical pipe 20 via a polymer tube 60, and the vibrator 61 is arranged in the axial direction of the pipe 20. Try to generate a forward wave. However, in this case, only the ink in the pipe 20 is vibrated, and the pipe 20 itself is not vibrated directly. Therefore, the pipe 20 is connected to the piezoelectric element 61 by the polymer tube 60. When this tube 60 is inserted, it is possible to prevent the pipe itself from causing a complicated resonance, and it is also possible to transmit vibration of equal strength to each nozzle. Further, in this case, since only one vibrator is required, the cost is further reduced.

By the way, in the above-described embodiment, the concave portion 22 formed around the nozzle hole 21 is provided for each nozzle separately. As shown in FIG. 6, a notch is formed along the axial direction of the pipe 20. The multi-nozzle head may be configured by forming the portion 70 continuously and forming the plurality of nozzle holes 21 in the cutout portion 70. The cutout 70 is a pipe
If 20 is processed at the time of extrusion molding, the recess processing time can be shortened. The cutout portion 70 can also be processed by electric discharge machining, electrolytic polishing, or the like.

The cutout portion 70 shown in FIG. 6 may be formed as a continuous recess 80 as shown in FIG. 7, and the nozzle hole 21 may be formed in this recess.

The manufacturing method has been described above based on the molded stainless steel pipe, but a cylindrical pipe or a recess formed in the pipe may be formed by electroforming, and a nozzle may be formed in the recess by electrical discharge machining.

[Effects of the Invention] As described above, according to the present invention, ink is filled in a cylindrical base material having a nozzle, and a vibrator is directly attached to the outer peripheral wall of the cylindrical base material other than the cutout portion. Since the ink is vibrated by being applied, the risk of electrical short circuit is reduced, and a simple and low cost nozzle head with a small number of parts can be realized.

[Brief description of drawings]

1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA 'of the same embodiment, FIG. 3 is a perspective view showing a vibrator and the like provided in the same embodiment, and FIG. FIG. 5 is a perspective view showing another embodiment of the present invention, FIG. 5 is a perspective view showing another embodiment of the present invention, and FIG. 6 is a perspective view showing a modified example of a recess formed around the nozzle. FIG. 7 is a perspective view showing still another modification of the recess, and FIG. 8 is a sectional view showing an example of a conventional device. 20 …… Pipe base material, 21 …… Nozzle, 22,80 …… Concave, 30
…… Ink supply tube, 40, 50, 61 …… Transducer, 60 ……
Polymer tube, 70 ... Notch.

Claims (1)

[Scope of utility model registration request] 1. A cutout portion is formed intermittently or continuously along the axial direction on a part of the outer peripheral wall of a circular tubular base material, and a plurality of nozzle holes for ejecting ink are formed in the cutout portion. At the same time, the circular tube-shaped base material is filled with ink, and a vibrator for vibrating the ink is attached to an outer peripheral wall of the circular tube-shaped base material other than the cutout portion. Nozzle head of inkjet printer.