JPS59230659A - Atomizing apparatus - Google Patents

Abstract

PURPOSE:To obtain an atomizing apparatus low in heat loss and reduced in the mechanical strain in the connection part of a piezoelectric vibrator, by reducing vibration energy as compared with the vibration energy during actual spraying for a predetermined period from the point of time when vibration energy begins to be applied. CONSTITUTION:Energy smaller than a driving energy level during a steady period is applied for a predetermined time from the point of time when a drive signal begins to be applied, that is, for a period during which the mechanical vibration of a piezoelectric vibrator 9 reaches a predetermined level. Whereby, the heat loss of driving energy is lowered even when an atomizing amount is controlled by duty control and the strain to the connection part of the piezoelectric vibrator is reduced and a sufficient atomizing amount is obtained by smooth vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid atomization device that atomizes liquid fuel such as kerosene or light oil, water, medicinal solution, recording liquid, etc. using an electric vibrator. .

Conventional configurations and their problems Various types of liquid atomization devices have been proposed in the past, and many of them utilize the vibration phenomenon of piezoelectric vibrators.

For example, inkjet recording devices that have been put into practical use in recent years have a configuration in which a piezoelectric vibrator is provided at one end of the liquid chamber and an orifice is provided at the other end. This is an atomization device that transmits ultrasonic waves to an orifice, and as a result, sprays ultrasonic atomized particles with a higher scattering speed than the orifice. FIG. 1 shows the driving state of this atomization device. FIG. 1(a) shows a pulsed rectangular wave drive signal with a predetermined period, and FIG. 1(b) shows how the amplitude of the piezoelectric vibrator changes when the drive signal is applied. There is. In the case of this inkjet device,
Since the amount of ink ejected at one time is small, the applied vibration energy may also be small, and even if a rectangular wave is applied at a predetermined level from the beginning, no failure will occur in the atomizer configuration.

FIG. 2 shows a conventional example of drive energy control means when a large amount of spray is produced by an ultrasonic atomizer using a piezoelectric vibrator as described above. The piezoelectric vibrator is driven to oscillate near the mechanical resonance point to atomize the liquid in the liquid chamber, and the means for controlling the amount of spray is a tutee control that changes the ratio between the application time of the drive signal and the stop time. be. (,)teeth,
This is a time characteristic in which the drive waveform is controlled at a predetermined level, and (b) shows the amplitude change of the piezoelectric vibrator corresponding to the drive energy in (,). In (a), energy is applied at the steady signal level from the start of application of the drive signal, but as in (b), when the signal application starts, the mechanical amplitude does not follow, and after a predetermined time constant. It can be seen that a steady state has been reached. That is, at the beginning of signal application, not all of the applied energy contributes to mechanical vibration, but even if a large amount of energy is applied, it results in heat loss.

In this way, in conventional data control, a large level of driving energy is applied from the beginning at the time of start-up, resulting in heat loss and lowering conversion efficiency. The distortion was large, and problems remained in terms of service life.

OBJECT OF THE INVENTION The present invention solves such conventional problems, and even when adjusting the amount of atomization by duty control, it reduces the heat loss of drive energy, reduces the strain on the joint of the piezoelectric vibrator, and ensures smooth vibration. The aim is to obtain a sufficient amount of atomization.

Structure of the Invention In order to achieve this object, the present invention includes a body including a pressurized chamber filled with a liquid, a supply section for supplying liquid to the pressurized chamber, and a body configured to face the pressurized chamber. an atomizer comprising a nozzle part having a nozzle provided in the nozzle, an electric vibrator that energizes the nozzle part to vibrate the nozzle, and an oscillation drive that drives the electric vibrator at a predetermined frequency. Department and
a duty control unit that controls a ratio of a drive signal application time to a stop time to the electric vibrator; and a duty control unit that applies vibration energy smaller than vibration energy during steady driving for a predetermined time at the start of the drive signal application. It is equipped with a vibration energy control section.

This configuration has the effect of applying energy smaller than the drive energy level during normal operation for a predetermined period of time from the start of application of the drive signal, that is, a period during which the mechanical vibration of the piezoelectric vibrator reaches a predetermined level.

DESCRIPTION OF EMBODIMENTS Referring to FIG. 3, an atomizer which is an embodiment of the present invention will be described. A body 2 provided with a pressurized chamber 1 filled with liquid is fixed to a support plate 4 with screws 3.

The liquid enters the pressurizing chamber 1 through the supply pipe 5, and during the atomization operation, the vibro for gas discharge is filled halfway. Reference numeral 7 denotes a nozzle portion facing one side of the pressurizing chamber 1, and its outer periphery is joined to the body 2. A spherical protrusion 8 having a fine hole for ejecting droplets is formed in the center of the nozzle part 7. Furthermore, the nozzle part 7 is equipped with an annular electric vibrator, here a piezoelectric element 9. This piezoelectric element 9 is a piezoelectric ceramic polarized in the thickness direction.
It has electrodes on the joint surface with the nozzle and on the opposite surface. Reference numeral 10 denotes a lead wire for transmitting a drive signal to the piezoelectric element 9, one of which is soldered to one electrode surface of the piezoelectric element 90, and the other is connected to the body 2 with a helix 11. When the mechanical vibration of the piezoelectric element 9 is excited by the drive signal, the nozzle part 7 is also energized and vibrates, so that the liquid in the pressurizing chamber 1 is discharged as atomized particles 12 as a result.

By the way, the liquid supplied to the pressurizing chamber 1 may be filled halfway with the vibro for gas discharge in the atomizer installation configuration, but as an alternative, in the atomizer installation configuration, the liquid supplied to the pressurizing chamber 1 and The exhaust vibro is empty, and before entering the droplet ejection sequence, for example, negative pressure may be applied through the exhaust vibro to fill the pressurizing chamber 1 with liquid and draw the exhaust vibro halfway up.

According to the latter method, impurities in the liquid solidify in the nozzle hole and the problem that droplets cannot be ejected does not occur.

FIG. 4 shows a block diagram of the atomization device of the present invention,
A piezoelectric vibrator 9 is excited to mechanically vibrate by a signal from the oscillation drive section 13. The configuration of the oscillation drive unit may be a separately excited type having an oscillator therein [It may be a self-excited type using the electrical characteristics of the piezoelectric vibrator described in 7 and 9. The data control section 14 controls the ratio between the application time of the drive signal from the oscillation drive section 13 and the stop time, and as a result, adjusts the amount of liquid discharged from the atomizer. Reference numeral 15 denotes a vibration energy control section, which adjusts the amount of vibration energy from the oscillation drive section, and controls vibration energy smaller than the vibration energy during steady drive during the initial predetermined time of the drive signal application time by the data control. Control the application to the piezoelectric vibrator.

In the above configuration, since a smaller amount of vibration energy is applied at the start of application of the drive signal than the vibration energy in the steady state, heat loss until the mechanical vibration follows up is significantly reduced, and
The atomizer configuration has the advantage that mechanical strain on the piezoelectric vibrator joints is reduced.

FIG. 5 shows another embodiment of the present invention, and shows how the amount of energy is adjusted when vibration energy is applied during data control. The figure shows only the envelope, and there is an ultrasonic vibration waveform inside. The horizontal axis represents elapsed time, and the application of vibrational energy is started from t=to, and the vibrational energy increases stepwise until t'=t+. A steady state is entered at t=tl, and a predetermined amount of vibrational energy is applied at 1=t21.

Said 1 = 16 to 1 = 1. Until now, mechanical vibrations were excited smoothly with a value smaller than the vibration energy during steady state.

FIG. 6 shows another embodiment of the invention in which the vibrational energy increases exponentially and reaches a steady state. This figure also shows only the envelope. Since there is no part that increases in a stepwise manner as shown in Fig. 5, it is possible to produce even smoother vibration. Fig. 7 shows another embodiment of the present invention, in which the vibration increases in a nearly straight line. The vibrational energy is increased to reach a steady state. In this increasing method, since the increase value of the vibration energy is the same change, the mechanical vibration also gradually generates a predetermined amplitude at a predetermined energy value.

Effects of the Invention As described above, the atomization device of the present invention provides the following effects.

For a predetermined period from the start of vibration energy application, a value smaller than the vibration energy used when actually spraying is applied, so mechanical vibrations are gradually excited, resulting in less heat loss than when applying large vibration energy from the beginning. Furthermore, since there is little mechanical strain at the joints of the piezoelectric vibrators, the service life of the piezoelectric vibrators is extended.

[Brief explanation of the drawing]

Figures 1a and b are drive waveform diagrams and amplitude change diagrams of piezoelectric vibrators used in inkjet recording devices, and Figure 2a is
, b is a diagram showing drive waveform diagrams and amplitude changes of date control for a conventional piezoelectric vibrator, FIG. 3 is a sectional view of an atomizer showing an embodiment of the present invention, and FIG. 4 is a diagram showing the same atomizer. The block diagram of the apparatus, FIG. 5, FIG. 6, and FIG. 7 are waveform diagrams showing other embodiments of applying the same vibrational energy. 1... Pressure chamber, 2... Body, 5...
Supply unit, 7... Nozzle unit, 9... Electric vibrator, 13... Oscillation drive unit, 14... Data control unit, 15... Vibration energy control unit Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2: Driving liquid amplitude change Figure 2, Horse a motion waveform amplitude change Figure 3

Claims (1)

[Claims] (1) A body including a pressurizing chamber filled with liquid, a supply section for supplying liquid to the pressurizing chamber, a nozzle section having a nozzle facing the pressurizing chamber, and the nozzle. an atomizer comprising an electric vibrator that vibrates the nozzle by energizing the nozzle; an oscillation drive unit that drives the electric vibrator at a predetermined frequency; and a drive signal to the electric vibrator. It is composed of a duty control section that controls the ratio between the application time and the stop time, and a vibration energy control section that applies vibration energy smaller than the vibration energy during steady driving for an initial predetermined time of the drive signal application time. Device? ) A vibration energy control unit that gradually increases the vibration energy from a predetermined value at the start of application of the drive signal and controls the application of vibration energy during steady driving. .