KR200168788Y1 - Ink jetting apparatus - Google Patents

Abstract

Applied to an inkjet print head, an ink injection device using an electrostatic force is disclosed. The disclosed ink jetting device includes a vibrating plate 32 which vibrates to press ink in the ink chamber to eject ink from the ink chamber 38 through the nozzle 37, a movable electrode 33 attached to the vibrating plate, and A fixed electrode 34 is fixedly spaced apart from the movable electrode. When a voltage having a predetermined potential difference is applied to the two electrodes, ink is ejected by vibrating the diaphragm together with the movable electrode due to the electrostatic force acting due to the potential difference between the two electrodes. It is possible to control the amount and speed of ink, which is suitable for high resolution and high speed printing.

Description

Ink jet device

The present invention relates to an ink ejection apparatus applied to an inkjet print head, and more particularly, to an ink ejection apparatus for ejecting ink using an electrostatic force.

Ink jetting devices applied to conventional drop-on-demand (DOD) inkjet printheads are roughly classified into heating ink jetting devices using surface heating elements and piezoelectric ink jetting devices using piezoelectric elements.

In these ink ejection apparatuses, the ink ejection value of the heating method using the surface heating element is, as shown in Fig. 1, the lower insulating layer 2, the heating element 3, and the electrodes 4, 5 on the substrate 1; ), The upper insulating layer 6 and the protective layer 7 are formed in this order, and an ink chamber 10 is formed by providing a flow path wall 8 between the nozzle plate 9 and the protective layer 7. Is done.

Here, the ink chamber 10 is connected to an ink tank (not shown), and the positive electrodes 4 and 5 are connected to the driving signal generator 12, and the electrodes 4 and 5 from the driving signal generator 12. When a driving signal is applied to the heating element 3 through the heating element 3, the heating element 3 is heated and the ink 13 in the ink chamber 10 is boiled.

At this time, bubbles 14 are generated in the ink chamber 11, and the generated bubbles 14 push the ink 13 in the ink chamber 10 out of the nozzle 11 of the nozzle plate 9 to discharge ink 15. ) The discharge ink 15 is ejected in accordance with a drive signal, that is, a print signal.

On the other hand, the piezoelectric ink jetting device using the piezoelectric body, as shown in Fig. 2, the substrate 16, the diaphragm 17, the piezoelectric element 18, the spacer 19 and the nozzle plate 20 It consists of.

When the driving signal is applied to the piezoelectric element 18 from the drive signal generator 23 of the piezoelectric ink jetting apparatus configured as described above, the piezoelectric element 18 is stretched mechanically, and the piezoelectric element 18 is stretched. The ink 24 in the ink chamber 21 is pushed out of the nozzle 22 to produce the discharge ink 25.

However, in the above-described conventional ink spraying device, the heating ink spraying device takes some time to generate sufficient bubbles, and thus there is a limit in improving the ejection speed of ink, that is, the printing speed, and the characteristic of the heating element is the ambient temperature. There was a problem that it is difficult to expect stable performance changed well under the influence of.

On the other hand, in the conventional ink jetting apparatuses as described above, the piezoelectric ink jetting apparatus can obtain better performance than the heating ink jetting apparatus, but it is expensive because it uses expensive piezoelectric elements. There was an expensive issue.

In addition, since both the heating element and the piezoelectric element must be well coordinated with the electrode, the insulating layer, the protective layer, etc., the manufacturing process is difficult, and thus there is a problem that the yield is low.

On the other hand, as a technique related to the present invention, US Patent Nos. 4,057,807 and 4,210,920 disclose an ink spraying device for ejecting ink by vibrating a magnetic copper plate with an electromagnet.

According to this, the conventional ink spraying device attaches a magnet driver to the outside of the nozzle of the head, seals the ink chamber with a magnetic copper plate that is distorted by the magnetic field generated by the magnetic driver, and the magnetic functional copper plate is formed by the magnetic field. The ink is discharged at a pressure that acts upon deformation into the outer grains.

However, according to the conventional ink ejection apparatus, when a magnet driver coil is excited, a secondary current is induced to another driver coil adjacent thereto, and thus, the magnetic function copper plate on the other driver side is operated, so that at other unwanted nozzles. There was a problem that ink tends to be ejected.

Therefore, not only is it difficult to obtain good print quality, but the magnet driver is attached to the outside of the nozzle, making it difficult to miniaturize the structure.

Therefore, the technical problem to be achieved by the present invention, that is, the object of the present invention is to solve the above problems of the conventional ink spraying device, it is easy to manufacture as a simple structure and has a stable operation characteristics as well as the It is to provide an ink spraying device that can improve the printing quality and printing speed by enabling the discharge pressure and speed control.

1 is a cross-sectional view of a conventional heating ink spraying device.

2 is a cross-sectional view of a conventional piezoelectric ink spraying device.

Figure 3 is a cross-sectional view of the ink injection device according to the present invention.

Figures 4a to 4e is a process diagram showing a process of manufacturing to have a curved portion by the residual stress in the diaphragm member constituting the ink injection value according to the present invention.

Figures 5a and 5b is a cross-sectional view showing the operating state of the ink jetting apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

30: silicon wafer substrate 31: groove

32: diaphragm 32: curved portion

33, 34: electrode 37: nozzle

38: ink chamber

An object of the present invention as described above is to constitute an ink ejection device having an ink chamber containing ink and a nozzle for ejecting ink from the ink chamber, wherein the diaphragm member vibrates to pressurize the ink in the ink chamber. As a means for driving the diaphragm member, two electrodes are used to attach the one electrode to the diaphragm member, and the other electrode is fixedly disposed at a slight distance from the one electrode, so as to have a potential difference between the two electrodes. It is achieved by providing an ink ejection device according to the present invention configured to vibrate the diaphragm member with its one electrode with an acting electrostatic force.

That is, the ink ejection device according to the present invention applies a voltage so as to have a potential difference between the two electrodes, and vibrates the diaphragm using an electrostatic force acting as the potential difference, thereby injecting ink at a pressure applied by the vibration of the diaphragm. To make it possible.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 shows an ink ejection apparatus according to the present invention. In Fig. 3, reference numeral 30 denotes a silicon wafer substrate. A groove 31 is formed on the upper surface of the silicon wafer substrate 30, and a diaphragm 32, which is a thin elastic body, is attached to the groove 31 by an adhesive.

In the formation of the diaphragm 32, a polymer or a ceramic thin film, which is a processing structure, is used as a non-conductor. Preferably, the curved portion of the diaphragm 32 is formed by a prestress in a portion where the groove 31 of the silicon wafer substrate 30 is located. It is produced so that 32a is formed.

The curved portion 32a is preferable for the momentary displacement and restoration during the vibration operation, and the manufacturing process of the diaphragm 32 will be described later. In the groove 31 formed in the silicon wafer substrate 30, the movable electrode 33 attached to the curved portion 32a of the diaphragm 32 and the fixed electrode 34 attached to the bottom surface of the groove 31 are located. It is.

These electrodes 33 and 34 are thin film coated using lithography and thin film coating techniques, which are then formed using sputtering, CVD, or the like.

On the other hand, the electrodes 33, 34 are spaced apart from each other, this interval affects the driving by the electrostatic force, and the required dimensions by wet or dry etching the groove 31 of the silicon wafer substrate 30 described above Acquire. The surface of the fixed electrode 34 is coated with an insulator 34a to avoid electrical shorts with the movable electrode 33.

On the diaphragm 32, a wall 35 for ink flow paths is attached and a nozzle plate 36 having a nozzle 37 is installed thereon and surrounded by the diaphragm 32, the wall 35, and the nozzle plate 36. This forms an ink chamber 38. This ink chamber 38 is filled with ink 39 connected to and supplied from ink supply means, not shown.

4A to 4E illustrate a preferred manufacturing process for forming the curved portion 32a by applying prestress to the aforementioned diaphragm 32.

That is, the SiO ₂ film 32 'as a raw material of the diaphragm 32 as the raw material for the above-mentioned ink flow path wall 35 on the front surface of the silicon wafer 35' is laminated to a thickness of 2 to 10 탆. oxidation) (see FIG. 4A), and lithography is used to wet etch the back surface of the silicon wafer 35 ′ (see FIG. 4A).

Then, as shown in FIG. 4C, in the exposed portion where the silicon wafer 35 'is removed, stress remains in a portion of the SiO ₂ film 32' that was in equilibrium with the silicon wafer 35 'in the previous step. In this way, the curved portion 32a is formed by prestressing.

Thereafter, the photoresist 42 is applied to the curved portion 32a (see FIG. 4D), and the silicon wafer 35 ′ is wet-etched secondly in consideration of the volume of the ink chamber 38 described above, and then the photoresist is formed. The resist 42 is removed to complete as shown in FIG. 4E.

The operation of the ink ejection apparatus according to the present invention configured as described above will be described with reference to FIGS. 5A and 5B.

When a fixed voltage is applied to the fixed electrode 34, and a signal modulated according to desired image information as a print signal is applied to the movable electrode 33 (at this time, the voltage applied to the fixed electrode 34 becomes the movable electrode 33). Must be greater than the signal voltage), and in this state, the curved portion 32a of the diaphragm 32 is attracted to the fixed electrode 34 together with the movable electrode 33 by the electrostatic force acting on the electrodes 33 and 34. It is deformed to be convex in the opposite direction, ie downward, as shown in FIG. 5A. At this time, the volume of the ink chamber 38 is expanded so that the ink 39 is not discharged but is further filled with the ink supplied from the ink tank described above.

In this state, when signals on both sides and the movable side of the electrodes 33 and 34 are turned off, the electrostatic force between the electrodes 33 and 34 is canceled, and the curved portion 32a of the diaphragm 32, which has been deformed inversely, is self-resilient to FIG. 5B. It is instantaneously restored to an initial state such as this, which results in a reduction in the volume of the expanded ink chamber 38 in the previous state. Therefore, ink 39 in the ink chamber 38 is discharged through the nozzle 37 at a pressure acting at the time of restoration.

By repeating this operation, the ejecting ink 40 is ejected from the nozzle 37 in accordance with the print signal to print a desired image.

Although not illustrated in the drawings, the curved portion of the aforementioned diaphragm is formed to be convex downward as an initial state, and both electrodes are driven by a signal that causes mutual repulsive force to be applied when voltage is applied, and the curved portion of the diaphragm is upward when the signal is applied. It will also be possible to drive the ink to be ejected in the convex primary deformation state.

Therefore, according to the ink ejection apparatus according to the present invention as described above, since the electrodes of the adjacent ink chambers do not malfunction when the electrodes of the ink chambers are driven, there is no undesired ink ejection phenomenon from the other nozzles, Therefore, there is an effect that printing of good quality is possible.

In addition, according to the ink ejection apparatus according to the present invention as described above, since the degree of deformation of the diaphragm can be adjusted by adjusting the magnitude and period of the voltage applied to the electrode, it is easy to control the amount and speed of ink ejected. It has the effect of being advantageous for high resolution and high speed printing.

In addition, according to the ink ejection apparatus according to the present invention as described above, since the electrode for operating the diaphragm is formed inside the nozzle, the structure can be made thin and compact, as well as simply thin film coating technology. Not only can it be manufactured, but the manufacturing process is simplified, so that the production cost can be lowered and distributed.

The present invention is not limited to the above described and illustrated by the drawings, and of course, more modifications and variations thereof are possible within the scope of the utility model registration claims described below.

Claims (6)

An ink chamber containing ink, a nozzle for discharging ink from the ink chamber, a diaphragm member capable of vibrating to press ink in the ink chamber, a movable electrode integrally attached to the diaphragm, and the movable member And a fixed electrode spaced apart from the electrode so that the diaphragm member vibrates together with the movable electrode by an electrostatic force acting on each other when a voltage having a potential difference is applied to both electrodes. Ink spraying device. The ink spraying device according to claim 1, wherein at least part of the diaphragm member is formed with a prestressed curved portion, and the movable electrode is attached to an image curved portion. According to claim 1 or 2, wherein the diaphragm member is attached to the substrate member, the substrate member is formed with a groove to allow at least a portion of the central portion of the diaphragm member to vibrate, the groove of the substrate member The ink injection device, characterized in that the both electrodes are located in. The ink spraying device according to claim 1, wherein at least one of the two electrodes is coated with an insulator. The ink ejection apparatus according to claim 1, wherein a constant voltage is applied to the fixed electrode, and a print signal modulated according to image information is applied to the movable electrode. The ink spraying device according to claim 5, wherein the voltage applied to the fixed electrode is set to be greater than a signal voltage of the movable electrode.