JPH09290504A - Liquid droplet ejector and printer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance resolving power by eliminating the shift of a liquid droplet emitting position from the focus of an acoustic lens by controlling the emitting direction of the liquid droplets emitted from the vicinity of the focus of the acoustic lens by regulating the vibration phases of at least two vibrators among a plurality of vibrators. SOLUTION: A member 3 arranged so that the focal position of an acoustic lens 7 formed to a first surface becomes the vicinity of the liquid surface 2 of ink, a plurality of vibrators 4a, 4b generating ultrasonic waves same in drive frequency propagated through the member toward the acoustic lens 7 are provided and a plurality of the vibrators 4a, 4b are arranged on the second surface of the member 3 along a predetermined direction and the acoustic lens 7 is arranged so that the focal position of the acoustic lens 7 becomes the vicinity of the liquid surface 2 of ink 1. By regulating the vibration phases of at least two vibrators among a plurality of the vibrators 4a, 4b, the emitting direction of liquid droplets emitted from the vicinity of the focus of the acoustic lens can be regulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus such as an ink jet printer for printing characters and image information on a recording paper by using ultrasonic waves to eject liquid droplets from the liquid surface of ink as needed. In particular, the present invention relates to a droplet ejector for ejecting ink droplets in this printing apparatus.

[0002]

2. Description of the Related Art One of the characteristics of the ink jet system is that it is a non-contact system in which ink is first ejected as droplets directly onto a recording paper so that the ink is attached and fixed on the recording paper. Since it is non-contact, the print head is not worn and the print head is not damaged by dust on the recording paper. Further, since there is no fear of electrostatic damage due to friction with an ink sheet or the like, it is highly reliable and has a long life of the print head. Furthermore, it has a quiet sound and can print on plain paper.

There are several types of ink jet printers, which are roughly classified into two types. One is called a "continuous type", and ink droplets continuously ejected from a nozzle are charged and deflected. The electrodes control the flight direction of the ink, and the other is called an "on-demand system", in which ink droplets are ejected from nozzles one by one as needed.

The system shown in the present invention is one of the on-demand systems and is called the "ultrasonic system". The ultrasonic method is a method of ejecting ink droplets from the liquid surface of the ink by the force of the pressure wave that converges the ultrasonic waves, and the ultrasonic waves generated in the liquid of the ink by a piezoelectric element etc. It is a method of ejecting droplets from the liquid surface by focusing on the surface.

The ultrasonic system ejects ink droplets from the liquid surface only by focusing the ultrasonic waves on the liquid surface, and therefore, unlike other on-demand systems, does not require a nozzle for narrowing the ink droplet diameter. Is.

Regarding the history of the droplet ejector using ultrasonic waves, first in 1927, RW Wood and A. L. Lumis (A.
L. Loomis, Ph.D., "Droplet ejection by ultrasonic waves"
ilos. Mag. Ser. 7, Vol. 4, No. Two
It seems to be the first to report in 2. In addition, 19
In 35, J. Gruetzmacher described “focusing ultrasonic waves by a lens” on focused ultrasonic waves by Z. physi
Introduced in k, 96. However, these two cases have not yet been applied to printers.

FIG. 36 shows US Pat. No. 4,308,547.
It is a figure for demonstrating an example of the conventional droplet ejector described in the publication. In FIG. 36, 130 is a plate, 1
40 is ink, 150 is a crystal oscillator, 160, 170,
180 and 190 are electrodes. The droplet ejector of FIG. 36 is used as a crystal oscillator 150 curved in a concave shape in order to focus ultrasonic waves on the liquid surface. Then, electrodes 160, 170, 180 and 190 are attached to the crystal oscillator 150, and the ejection direction of the droplets is changed by selectively driving these electrodes.

FIG. 37 is a view for explaining another example of the conventional droplet ejector disclosed in Japanese Patent Laid-Open No. 62-66943. In FIG. 37, 210 is a flat substrate, 220 is a pair of ring-shaped electrodes concentrically attached in a comb shape on the upper surface of the substrate 210, and 230 is the ejection position of the droplet 200 ejected from the ink 140. The protrusion electrode 220 is a protrusion electrode for adjustment, and the protrusion electrode 220 has a comb shape. The substrate 210, the electrode 220, and the overhanging electrode 230 form a surface acoustic wave transducer. The droplet ejector of FIG. 37 uses a planar surface acoustic wave transducer instead of a concave acoustic lens to focus ultrasonic waves on the liquid surface.

In the droplet ejector of FIG. 37, a coherent Rayleigh wave propagating in a radial direction is generated on the surface by AC driving a pair of ring-shaped electrodes 220, and is focused on the liquid surface due to the shape of the transducer. As a result, droplets are ejected.

Further, by adding at least one electrically independent comb-shaped projecting electrode to the outside of the electrode 220, an asymmetric Rayleigh wave can be generated, whereby the focus position of the ultrasonic wave is changed to the liquid level. It is possible to shift with. However, this is the control of the ejection position of the droplets and not the ejection direction.

FIG. 38 is a diagram for explaining another example of the droplet ejector described in Japanese Patent Laid-Open No. 62-264962. In FIG. 38, 200a and 200b are droplets ejected from the focal position, 240a and 240b are transducers, 250a and 250b are ring-shaped conductors, and 2a.
Reference numerals 60a and 260b are ring-shaped counter electrodes. The conductor 250a (250b) and the counter electrode 260a (260
b) is attached so as to be concentric with the focus of the pressure wave generated by the transducer 240a (240b). The conductor 250a and the counter electrode 260a constitute a controller 270a that controls the ON / OFF of the transducer 240a and the ejection direction. The conductor 250b and the counter electrode 260b constitute a controller 270b that controls the on / off of the transducer 240b and the ejection direction. The droplet ejector of FIG.
By controlling the pressure waves excited by 0a and 240b by the controllers 270a and 270b provided near the liquid surface, on / off of droplet ejection and ejection direction control are performed.

The controller 270a (270b) includes a ring-shaped conductor 250a (250b) and a counter electrode 260a.
A periodic high voltage pulse is applied between (260b) and a dielectric force acts on the liquid to generate a surface tension wave. This allows the surface tension wave and the transducer 24
0a (240b) is caused to interfere with the pressure wave of the ultrasonic wave to control the ejection of the droplet.

Further, the conductor 250a (250b) and the counter electrode 260a (260b) are divided in the middle of the circumference to be electrically independent, and the controller 270a (270b).
By differentially driving the voltage of the pulse of
The ejection angle of 00a (200b) can be changed.

FIG. 39 is a sectional view showing another example of the droplet ejector disclosed in Japanese Patent Laid-Open No. 63-162253. In FIG. 39, 1 is ink, 2 is ink level, 3
Is a substrate, 4 is a vibrator attached to the bottom surface of the substrate 3, 5
Is a lead of the oscillator 4, 6 is an ultrasonic wave transmitted from the oscillator 4 to the substrate 3, and 7 is an ink surface 2 formed on the upper surface of the substrate 3.
It is an acoustic lens whose curvature (or radius of curvature) is determined so as to focus on. Reference numeral 8 is a focused ultrasonic wave focused toward the focal point by the acoustic lens 7, 9 is a focal point of the focused ultrasonic wave 8, and 10 is a droplet ejected from the ink surface 2.

In operation, a high-frequency drive signal is applied from a signal source (not shown) to the vibrator 4 through the lead 5, the vibrator 4 vibrates in the thickness direction, and the ultrasonic wave 6 is transmitted to the substrate 3. The ultrasonic wave 6 propagates through the substrate 3 and reaches the acoustic lens 7. Next, the ultrasonic wave 6 is refracted by the acoustic lens 7 and becomes a focused ultrasonic wave 8 which travels through the ink 1 and is focused on the ink liquid surface 2. Then, the droplet 10 is ejected from the focusing point 9 whose pressure is increased by the focused ultrasonic wave 8.

The principle of droplet formation using focused ultrasonic waves is described in J. Appl. Phys. 65 (9), 1
May 1989, S. A. "Nozzleless drop form by Elrod and others
ation with focused accout
ic beams ”.

[0017]

In the droplet ejector shown in FIG. 36, it is necessary to form an acoustic lens on a curved surface in order to focus the ultrasonic wave emitted from the crystal oscillator 150. Therefore, there is a problem that the manufacture of the crystal unit 150 becomes complicated. Further, the crystal oscillator 150
Since it depends on the number of electrodes attached to the electrode, the number of directions that can be ejected is limited, and it is a problem that finer control is not possible. Therefore, the droplet ejector shown in FIG.
The device has a complicated structure such as forming 0 in a concentric circle shape and is a device for controlling the discharge position rather than controlling the discharge direction of the liquid droplet, so that the liquid droplet discharge position deviates from the originally intended position. There was a problem. The droplet ejector shown in FIG. 38 includes a conductor 250a (250b) and a counter electrode 2
Not only is the device configuration complicated, such as arranging it so as to be concentric with 60a (260b), but also the controller 270
Since it is necessary to arrange a and 270b in the ink, there is a problem in that the number of parts is large. Further, in the configuration of the droplet ejector shown in FIG. 39, the ejection direction of the droplet cannot be controlled, and in order to control the ejection direction, in addition to the vibrator 4 and the acoustic lens 7, the ejection direction of the droplet 10 is controlled. However, there is a problem that the number of parts is increased due to the need for an additive for controlling the. The droplet ejector of the present invention has been made to solve the above problems, and an object thereof is to obtain a droplet ejector having a simple configuration, high resolution, and short printing time, and a printing apparatus using the same. To do.

[0018]

A droplet ejector according to the present invention is a member which is located in ink and is arranged such that the focal point of an acoustic lens formed on the first surface is near the liquid surface of the ink. A plurality of transducers that generate ultrasonic waves having the same drive frequency that propagates in the member toward the acoustic lens are arranged, and the plurality of transducers are arranged along a predetermined direction on the second surface of the member, By adjusting the phase in which at least two of the vibrators vibrate, the ejection direction of the liquid droplets ejected from near the focus can be adjusted.

The droplet ejector according to the present invention has a plurality of members, and the plurality of members are arranged in a predetermined direction.

In the liquid drop ejector of the present invention, the member is a rectangular parallelepiped member, and a plurality of vibrators are arranged in a grid pattern on the second surface facing the first surface.

In the droplet ejector of the present invention, the member is a plate-shaped member, and a plurality of vibrators are provided on the second surface, which is the end surface facing the first surface, which is the end surface of the plate-shaped member. It is arranged along a predetermined direction.

The droplet ejector of the present invention comprises the first member
Is a rectangle, and the diameter of the acoustic lens formed on the first surface is larger than the length of the short side of the rectangle.

In the droplet ejector of the present invention, a member whose center of the diameter of the acoustic lens is located at the midpoint of the short side of the first surface and which is on a straight line perpendicular to the first surface has the center of the diameter. It is arranged in two rows alternately so as to be located on a predetermined straight line.

In the droplet ejector according to the present invention, the center of the diameter of the acoustic lens is located at the midpoint of the long side of the first surface, and the member on the straight line perpendicular to the first surface is the center of the diameter. It is arranged in two rows alternately so as to be located on a predetermined straight line.

The droplet ejector of the present invention synchronizes the phase change of the drive signal for driving the plurality of vibrators arranged in each member, and synchronizes the phase of the drive signal for driving the plurality of vibrators arranged in each member. The liquid droplets are selectively ejected by periodically changing and controlling the drive of each transducer according to the image signal.

The droplet ejector of the present invention has slits formed in the member so as to separate the individual ultrasonic waves generated by the vibration of the individual vibrators arranged on the second surface.

The droplet ejector of the present invention is configured to increase the amplitude of the drive signal for driving these vibrators as the phase difference between at least two vibrators increases.

The droplet ejector of the present invention has a member provided with a hole having a diameter smaller than the diameter of the droplet, and the member is made of ink so that the hole is located at a position corresponding to the focal point of the acoustic lens. It is placed on the liquid surface.

The droplet ejector of the present invention has a member provided with a slit having a width smaller than the diameter of the droplet,
Further, the member is arranged on the liquid surface of the ink so that the slit is located at the position corresponding to the focus of the acoustic lens.

The printing apparatus of the present invention is a printing apparatus which ejects droplets from ink and makes the droplets adhere to the recording paper for printing, which is located in the ink and formed on the first surface. A plurality of vibrators provided with a member arranged so that the focus position of the acoustic lens is near the liquid surface of the ink and a plurality of vibrators that generate ultrasonic waves with the same drive frequency propagating in the member toward the acoustic lens. Are arranged along a predetermined direction on the second surface of the member, and the phase in which at least two vibrators of the plurality of vibrators vibrate is adjusted to discharge the droplets discharged from near the focal point. It is provided with a droplet ejector configured so that its direction can be adjusted.

The printing apparatus of the present invention comprises a plurality of members, and the plurality of members are arranged in a predetermined direction.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 is a sectional view showing a droplet ejector of the first embodiment. In FIG. 1, 1 is ink contained in a desired container (not shown), 2 is an ink liquid surface which is the liquid surface of the ink 1, and 3 is ultrasonic waves generated by vibration of a vibrator described later. The member 3 is a member for propagation, and the member 3 is, for example, a rectangular parallelepiped member. In particular, here, a case where a plate-shaped substrate is used for the member 3 will be described as an example. Reference numerals 4a and 4b denote vibrators attached to the lower surface (or lower end surface) of the second surface of the substrate 3, and reference numerals 5a and 5b denote leads of the vibrators 4a and 4b, respectively. 6a and 6b are ultrasonic waves transmitted from the transducers 4a and 4b into the substrate 3, and 7 is an acoustic lens. The acoustic lens 7 is arranged in the ink 1 so that its focal point is near the ink liquid surface 2. Further, the acoustic lens 7 has a concave shape whose curvature (or radius of curvature) is determined. The acoustic lens 7 is formed on the upper surface (or upper end surface) that is the first surface of the substrate 3, and the upper surface that is the first surface and the lower surface that is the second surface are in a positional relationship of facing each other. Here, it is assumed that the focus position of the acoustic lens 7 is located on the ink liquid surface 2. Reference numeral 8 denotes a focused ultrasonic wave which is focused toward the focal point of the acoustic lens 7. The focused ultrasonic wave 8 is a focused ultrasonic wave 8a in which the ultrasonic wave 6a is refracted by the acoustic lens 7 and a focused ultrasonic wave 6b in which the ultrasonic wave 6b is refracted by the acoustic lens 7. It has a sound wave 8b. 9 is focused ultrasound 8
Focusing points 10 where a and 8 b are focused are droplets ejected from the focusing point 9. Since the focus of the acoustic lens 7 is located on the ink liquid surface 2, the focusing point 9 is also located on the ink liquid surface 2.

Channel 1 (ch.1) to lead 5a
Signal input to the oscillator 4a through the channel 2
(Ch.2) When there is a phase difference with the signal input to the vibrator 4b through the lead 5b, the ultrasonic waves 6a and 6b transmitted in the substrate 3 have a phase difference. When the ultrasonic waves 6a and 6b have a phase difference, the focused ultrasonic waves 8a and 8b have a phase difference, and the ejection direction of the droplet 10 ejected from the ink liquid surface 2 changes by an angle corresponding to this phase difference. Focused ultrasound 8
When the phase difference between a and 8b is 0, the droplet 10 is ejected in the direction perpendicular to the ink liquid surface 2. Therefore, by controlling the phase difference between the signal input to the vibrator 4a and the signal input to the vibrator 4b, the ejection direction of the droplet 10 ejected from the ink surface 2 can be controlled. Is possible.

FIG. 2 is a diagram showing an example of signals input to the vibrators 4a and 4b of the droplet ejector of the first embodiment shown in FIG. In the first embodiment, channel 1 (ch.
1), transducers 4a, 4b from channel 2 (ch.2)
A case where a burst signal is input as the signal will be described as an example. In FIG. 2, 11a and 11b are channel 1 (ch.1) and channel 2 (ch.2), respectively.
Burst signals input to the vibrators 4a and 4b from the oscillators 4a and 4b, both having a period T1 and an amplitude V. 12a and 12b are drive signals having a gate width T2 included in the burst signals 11a and 11b. The drive signals 12a and 12b have the same drive frequency, and ch. 1, ch. Send at the same timing between the two.

FIG. 3 is a diagram showing a specific example of the drive signals 12a and 12b. Here, a rectangular wave having the same drive frequency as the drive signal will be described as an example. Also,
The phase difference between these two rectangular waves is represented by φ. Drive signal 12
a and 12b respectively transmit at the same timing, but when these signals (that is, two rectangular waves) have a phase difference,
The ejection direction of the droplets changes according to this phase difference. Also,
The drive frequencies of the drive signals 12a and 12b are the vibrators 4a and 4
The resonance frequency is usually b, and an example using a rectangular wave is described here, but a sine wave or a triangular wave may be used instead of the rectangular wave.

Next, the operation will be described. First, the drive signals 12a and 12b included in the burst signals 11a and 11b shown in FIG. 2 are applied to the transducers 4a and 4b in FIG. 1, whereby the transducers 4a and 4b vibrate and the ultrasonic waves 6a and 6b. Is generated and transmitted to the substrate 3. Ultrasonic waves 6a, 6
b is transmitted through the substrate 3 and reaches the acoustic lens 7.

The acoustic lens 7 refracts the ultrasonic waves 6a and 6b transmitted through the substrate 3 and focuses the ultrasonic waves 8 into the ink 1.
Fire a and 8b. The focused ultrasonic waves 8a and 8b travel toward the ink surface 2 while being focused, and are focused at a focusing point 9. At this time, the focused ultrasonic waves 8a and 8b are combined to form a synthetic wavefront (not shown), and the traveling direction of the synthetic wavefront is determined by the phase difference between the two focused ultrasonic waves 8a and 8b.

At the focal point 9, focused ultrasonic waves 8a and 8b are generated.
The pressure in the vicinity of the ink surface 2 is increased by this to form a liquid column (not shown), the diameter of which is approximately equal to the diameter of the droplet 10. Also, the F number of the acoustic lens 7 (or F number
When the value) is 1, the focused ultrasonic waves 8a, 8 in the ink 1 are
It is almost equal to the wavelength λ of b. That is, when the wavelength λ is shortened, the diameter of the liquid column (not shown) is also reduced, and thus the diameter of the discharged droplet is also reduced.

Since the force of ejecting the droplet 10 by the pressure waves focused by the focused ultrasonic waves 8a and 8b is higher than the surface tension, the droplet 1 is moved from the ink surface 2 in the traveling direction of the composite wave surface.
0 is discharged. The ejection cycle of the droplet 10 is equal to the cycle T1 of the burst signals 11a and 11b shown in FIG. 2, and the energy applied to one droplet 10 is the burst signal 11a.
Rectangular wave 12a, 1a constituting the drive signal with the amplitude V of 11b
It depends on the length T2 of 2b.

Next, the relationship between the phase difference between the drive signals 12a and 12b and the ejection direction of the droplet 10 will be described. FIG. 4 is a diagram showing an example of the operation of the droplet ejector, and is a diagram showing how ultrasonic waves propagate when the ejection direction of the droplet 10 is perpendicular to the ink surface 2. FIG. 5 is a diagram showing an example of the drive signal, and ch1 of the droplet ejector of FIG.
The rectangular waves forming the drive signals 12a12b input to ch2 are represented, and the phase difference between these rectangular waves is zero.

Since the phase difference between the rectangular waves forming the drive signals 12a and 12b is 0, signals having exactly the same phase and the same amplitude are applied to the vibrators 4a and 4b.
As shown in FIG. 4, the ultrasonic waves 6 a and 6 b having the same phase are refracted by the acoustic lens 7 to be focused ultrasonic waves 8 a and 8 b, which are focused on the focusing point 9. At this time, droplets 10 are ejected from a liquid column (not shown) formed on the ink liquid surface 2 in a direction perpendicular to the ink liquid surface 2.

FIG. 6 is a diagram showing an example of the operation of the droplet ejector, in which the phase of the rectangular wave 12a forming the drive signal is advanced by φ from the phase of the rectangular wave 12b forming the drive signal. 10 shows the discharge directions of 10. FIG. 7 is a diagram showing an example of the drive signal, and shows rectangular waves forming the drive signals 12a and 12b input to the droplet ejector of FIG. In FIG. 7, the drive signal 12
a, 12b phase difference of the rectangular waves (ch. 1-c
h. 2) is indicated by φ, and ch. 1 is ch. It shows a state in which φ is advanced from 2.

In FIG. 6, ch. 1, ch. Drive signals 12a, 12b from 2
When the rectangular wave that constitutes the
Is transmitted by φ more than the ultrasonic wave 6b, and the focused ultrasonic wave 8
The composite wavefront formed by a and 8b is tilted to the right as compared to when the phase difference is zero, and as a result, the ejection direction of the droplet 10 is tilted to the right by θ with respect to the vertical direction.

Further, ch. 1, ch. If the phase difference φ of the rectangular wave constituting the drive signal given to 2 is increased, the ejection direction angle θ of the droplet 10 also increases, but as the phase difference increases, the amplitude of the composite wavefront decreases and the phase difference 180 degrees. The amplitude of the composite wavefront becomes zero. Further, when the phase of the rectangular wave forming the drive signal 12a is delayed by φ from that of the rectangular wave forming the drive signal 12b, the droplet 1 is reversed, contrary to FIG.
The discharge direction of 0 is inclined to the left by θ with respect to the vertical direction.

Next, a method for controlling the ejection direction of the droplet 10 will be described. FIG. 8 is a diagram for explaining a method of controlling the ejection direction of the droplet 10. FIG. 9 shows that when controlling the ejection direction of the liquid droplets 10, ch. 1, ch. 2 shows an example of the signal applied to the signal No. 2. In FIG. 9, ch. 1
Drive signal 12 constituting the burst signal 11a applied to the
The phases of the rectangular waves forming a are the same as each other. On the other hand, ch. C corresponding to one individual drive signal 12a
h. Drive signal 12 constituting the burst signal 11b of 2
The phases of the rectangular waves forming c, 12d, 12e, 12f, and 12g are different from each other.

In the first embodiment, the drive signal 12a and the drive signals 12c, 12d, 12e, 12f and 12g are designed to have the following phase differences. The drive signal 12a and the drive signal 12c have a phase difference of −90 degrees.
The drive signal 12a and the drive signal 12d have a phase difference of −45 degrees. The phase difference between the drive signal 12a and the drive signal 12e is 0. The drive signal 12a and the drive signal 12f have a phase difference of 45 degrees. The drive signal 12a and the drive signal 12g have a phase difference of 90 degrees. ch. 1 and the rectangular wave forming the drive signal 12a of ch. 2 drive signals 12c, 12d, 1
The phase difference of the rectangular waves forming 2e, 12f, and 12g changes from -90 degrees to 90 degrees by 45 degrees.

This signal is transmitted to the vibrators 4a and 4b in FIG.
, The ejection direction of the droplet 10 changes from left to right (scan). In this way, ch. Applied to the vibrators 4a and 4b. 1, ch. It is possible to control the ejection direction of the liquid droplets 10 by changing the phase difference of the drive signal input to the optical disc 2, and one droplet ejector can be used to control a plurality of lines on a predetermined straight line on the recording paper (not shown). Droplets 10 can be deposited at the points.

Here, ch. 1 and the rectangular wave forming the drive signal of ch. The example in which the phase difference of the rectangular wave forming the drive signal of No. 2 is changed by 45 degrees from −90 degrees to 90 degrees has been described. However, if the changing angle is further reduced, the ejection direction of the droplet 10 is controlled more finely. By changing the droplet 10 by a predetermined angle (that is, by scanning) with one droplet ejector, the distance between the droplets 10 attached on a predetermined straight line of the recording paper (not shown) can be increased. Is smaller, the resolution is increased. In addition, it is not necessary to form the vibrator in a complicated structure in order to change the discharge position of the droplet 10 as in the conventional case, and the configuration is simple. Also, the droplet 10
Since the ultrasonic waves 6a and 6b are focused by the acoustic lens 7 and ejected from the focal point 9, the ejection position of the droplet 10 (that is, the focal point 9 of the acoustic lens 7) does not shift. When the droplet ejector according to the first embodiment is used in a printing device such as an inkjet printer, the printing resolution is increased, so that the printing quality or the image quality is improved.

Embodiment 2 In the droplet ejector according to the first embodiment, ultrasonic waves having different phases interfere with each other in the substrate 3, so that the ejection direction of droplets may be deviated from the designed direction. The droplet ejector according to the second embodiment is made to solve the above-mentioned problem, and is characterized by having slits so that ultrasonic waves propagating in the substrate 3 do not interfere with each other. is there.

FIG. 10 is a sectional view of the droplet ejector of the second embodiment. In FIG. 10, 2 is an ink liquid surface, 3 is a substrate, 4c, 4d, 4e, 4f, 4g, and 4h are vibrators arranged in a line on the bottom surface of the substrate 3, respectively. 6
c, 6d, 6e, 6f, 6g and 6h are ultrasonic waves generated by the transducers 4c to 4h, respectively. Reference numeral 7 is an acoustic lens, and 8c, 8d, 8e, 8f, 8g and 8h are focused ultrasonic waves refracted by the acoustic lens 7, respectively.
Reference numeral 9 is a focal point of focused ultrasonic waves 8c to 8h. 10 is a droplet ejected from the ink surface 2 by the focused ultrasonic waves 8c to 8h, and 13a, 13b, 13c, 13d and 13e are respectively cut between the transducers 4c to 4h from the bottom surface of the substrate 3 toward the acoustic lens 7. It is an embedded slit. The slits 13a to 13e are provided at positions where the ultrasonic waves 6c to 6f do not interfere with each other.

Next, the operation of the droplet ejector of the second embodiment will be described. FIG. 10 shows a state in which burst signals having the same drive frequency and a phase difference of 0 are input from the signal source (not shown) to the transducers 4c to 4h. When the burst signal is input to the vibrators 4c to 4h, the vibrators 4c to 4h vibrate and the ultrasonic waves 6 are generated in the substrate 3.
c-6h are fired. These ultrasonic waves 6c to 6h propagate in the substrate 3 toward the acoustic lens 7.

At this time, the ultrasonic wave 6c propagating through the substrate 3
Since ~ 6h are acoustically separated from each other by the slits 13a to 13e, they reach the acoustic lens 7 without interfering with each other. Ultrasonic waves 6c reaching the acoustic lens 7
.About.6h are refracted by the acoustic lenses to form focused ultrasonic waves 8c to 8h, which are focused toward the focusing point 9. Since there is no phase difference between the ultrasonic waves 6c to 6h, the droplet 10 is ejected in the direction perpendicular to the ink surface 2.

As described above, the adjacent ultrasonic waves 6c in the substrate 3 are
Since ~ 6h do not interfere with each other, the ejection direction of the droplet 10 is more stable, and the focusing of ultrasonic waves is not sufficient, and the droplet diameter does not increase.

Further, FIG. 10 shows an example in which burst signals having no phase difference are input to the transducers 4c to 4h, but as shown in the first embodiment, the burst signals having different phases are provided to the transducers 4c to 4h. It is possible to control the ejection direction of the droplet 10 by changing the inclination of the composite wavefront formed at the focal point 9 by inputting. In that case, the droplet 10 is linearly scanned along a direction depending on the arrangement direction of the transducers 4c to 4h.

FIG. 11 is a diagram for explaining another example of the droplet ejector of the second embodiment. In FIG.
Reference numerals 13f, 13g, 13h, 13i, and 13j denote slits formed on the substrate 3 along the direction from the acoustic lens 7 to the lower surface of the substrate 3. In FIG. 10, the slits 13 a to 1 are formed in the direction from the lower surface of the substrate 3 toward the acoustic lens 7.
Although 3e is provided, as shown in FIG. 11, slits 13f to 13f are formed in the direction from the acoustic lens 7 side to the lower surface of the substrate 3.
Even if j is provided, the same effect as that of the droplet ejector shown in FIG. 10 can be obtained.

FIG. 12 is a diagram for explaining another example of the droplet ejector of the second embodiment. In FIG.
13k, 13l, 13m, 13n and 13o are vibrators 4c
It is a slit formed in the substrate 3 along a direction from the position of 4 h to the acoustic lens 7. As shown in FIG. 12, even if slits 13k to 13o are provided inside the substrate 3 in the direction from the positions of the transducers 4c to 4h to the position of the acoustic lens 7, the same effect as that of the droplet ejector shown in FIG. 10 can be obtained. can get.

Embodiment 3 The droplet ejector of the third embodiment is characterized by having a plurality of substrates and arranging the plurality of substrates along a predetermined direction. FIG.
FIG. 3 is a diagram showing the configuration of the droplet ejector of the third embodiment. In FIG. 13, 3a, 3b and 3c are substrates.
7a is an acoustic lens formed on the upper surface which is the first surface of the substrate 3a, 7b is an acoustic lens formed on the upper surface which is the first surface of the substrate 3b, and 7c is formed on the upper surface which is the first surface of the substrate 3c. It is an acoustic lens. 14a and 15a are the substrate 3
It is a vibrator arranged on the lower surface which is the second surface facing the first surface of a. Reference numerals 14b and 15b denote vibrators arranged on the lower surface which is the second surface facing the first surface of the substrate 3b. Reference numerals 14c and 15c denote vibrators arranged on the lower surface that is the second surface of the substrate 3c that faces the first surface.

Since the plurality of substrates 3a, 3b and 3c are arranged along a predetermined direction (on the straight line in the third embodiment), the focal points of the acoustic lenses 7a, 7b and 7c are also along the predetermined direction. To position. In the third embodiment, the substrate 3a,
Although 3 pieces of 3b and 3c are arranged, the number is not limited to 3, and any number of pieces may be arranged as necessary.

Reference numeral 20 is a drive signal generated from a signal generator (not shown). Reference numeral 18 is a phase variable circuit for changing the phase of the rectangular wave forming the drive signal. Reference numeral 19 is an image signal. 17a, 17b and 17c are amplifiers. The amplifier 17a amplifies the drive signal 20 and controls the transmission of the drive signal 20 to the vibrators 14a and 15a according to the image signal 19. The amplifier 17b amplifies the drive signal 20 and controls the transmission of the drive signal 20 to the vibrators 14b and 15b according to the image signal 19. The amplifier 17c amplifies the drive signal 20, and according to the image signal 19, the vibrators 14c, 1
It controls the sending of the drive signal 20 to 5c. Further, the amplitude of the drive signal 20 amplified by the amplifiers 17a to 17c is large enough to eject the droplet 10.

In the droplet ejector of the third embodiment, the amplifiers 17a to 17c are configured to control the on / off operation of the corresponding vibrators 14a to 14c and the vibrators 15a to 15c by the image signal 19. It is characterized by. That is, when one of the amplifiers 17a to 17c receives the image signal 19 for ejecting the droplet 10, the corresponding vibrators 14a to 14c and the vibrators 15a to 15c are received.
The amplified drive signal 20 is sent to c (this state is turned on). When any of the amplifiers 17a to 17c receives the image signal 19 for not ejecting the droplet 10 (or when the image signal 19 is not input when the drive signal 20 is received), the vibration corresponding thereto is generated. Child 14a
˜14c, the drive signal 20 is not sent to the vibrators 15a to 15c (this state is turned off).

When the operation is on, the amplifier 17a outputs the amplified drive signal 20 to the corresponding vibrators 14a, 1a.
5a, and a droplet 10 is ejected from the ink surface 2.
When the operation is on, the amplifier 17b sends the amplified drive signal 20 to the corresponding transducers 14b and 15b,
Droplets 10 are ejected from the ink surface 2. When the operation is on, the amplifier 17c sends the amplified drive signal 20 to the corresponding vibrators 14c and 15c, and ejects the droplet 10 from the ink surface 2. When the operation of the amplifier 17a is off, the drive signal 20 is transmitted to the vibrators 14a and 15a.
The droplet 10 is not ejected from the ink surface 2 because it is not sent to a. When the operation of the amplifier 17b is off, the drive signal 20 is not sent to the vibrators 14b and 15b, so that the droplet 10 is not ejected from the ink surface 2. When the operation of the amplifier 17c is off, the drive signal 20 is not sent to the vibrators 14c and 15c, so that the droplet 10 is not ejected from the ink surface 2.

Next, the operation of the droplet ejector of the third embodiment will be described. FIG. 13 is a diagram for explaining the operation of the droplet ejector of the third embodiment, and the vibrators 14a to 14c.
FIG. 13 is a diagram showing a state in which drive signals are input to all of the vibrators 15a to 15c and droplets are ejected. 13, burst signals 20 generated by a signal generator (not shown) are channel 1 (ch.1), channel 2
It is divided into (ch.2) and input to the amplifiers 17a to 17c. ch. Since the burst signal of 1 passes through the phase variable circuit 18, ch. It is possible to generate a phase difference with the burst signal of No. 2, but since the phase difference φ is set to φ = 0 in FIG. 13, ch. 1 and ch. The burst signal 20 of No. 2 is input to the amplifiers 17a to 17c with the same phase.

Next, the oscillators 14a to 14c and the oscillators 15a to 1c are turned on and off by turning on and off the amplifiers 17a to 17c.
The output of the amplified drive signal 20 to 5c is controlled,
The on / off of the outputs from the amplifiers 17a to 17c is controlled by the image signal 19. That is, the individual amplifiers 17a to 17c are ch. 1, ch. Every time the drive signal 20 is input from the No. 2, it is selected whether to send the amplified drive signal 20 to the vibrators 14a to 14c and the vibrators 15a to 15c according to the corresponding image signal 19.

The drive signal 20 amplified by the amplifiers 17a to 17c is applied to the corresponding vibrators 14a to 14c and 15.
a to 15c. Then, the vibrators 14a to 14
The ultrasonic waves (not shown) generated by the vibration of c, 15a to 15c propagate through the substrates 3a to 3c, are refracted by the acoustic lenses 7a to 7c, and are focused ultrasonic waves 16a to 16c.
c, which is focused on the ink surface 2 and drops 10a to 10c.
Are ejected from the ink surface 2 in a predetermined direction.

Further, in FIG. 13, ch. 1 and ch. 2 has a zero phase difference with the signal, the liquid droplet 10 is
Is ejected in a direction perpendicular to. Further, in FIG. 13, the signals of the amplifiers 17a to 17c are ON, and the acoustic lenses 7a to
Focused ultrasonic waves are emitted from 7c, and the droplet 10a-
10c discharges.

FIG. 14 is a diagram for explaining an example of the operation of the droplet ejector of the third embodiment, and a state in which droplets are selectively ejected by focused ultrasonic waves emitted from a predetermined acoustic lens will be described. FIG. Here, the oscillator 14
The case where the drive signal is not input to a, 14c, 15a and 15c but the drive signal is input to the vibrators 14b and 15b will be described. Further, FIG. 14 shows droplets 10a to 10c.
Of the burst signal 20 input to ch1 is advanced by φ by the phase variable circuit 18. As a result, the oscillator 14 in the substrates 3a to 3c is
The phase of the ultrasonic waves from a, 14b, and 14c is the oscillator 1
Since the phases of the ultrasonic waves from 5a, 15b, and 15c are advanced, the direction of the synthetic wavefront at the focal point is tilted to the right, and accordingly, the ejection directions of the liquid droplets 10a to 10c are also aligned and tilted to the right by θ.

FIG. 14 shows a state in which only the output of the amplifier 17b is on and only the liquid droplet 10b is ejected. Further, by the phase variable circuit 18, ch. Two
To ch. By periodically changing the phase of 1, it is possible to perform scanning while synchronizing the ejection directions of the droplets 10a to 10c.

As described above, the droplet ejector according to the third embodiment aligns the directions of the droplets ejected from the individual acoustic lenses 7, and simultaneously controls the ejection of the droplets in accordance with the ejection direction of the droplets 10. Therefore, the substrate 3 and the recording paper (not shown)
The droplets can be attached to a predetermined position on a predetermined straight line on the recording paper without changing the relative position to. In addition, there are advantages that the wiring of the entire circuit forming the droplet ejector is simple and the printing time is shortened. In the third embodiment, the amplifier controls the input to the vibrator, but this is not always necessary, and any configuration can be used as long as the droplet ejection can be controlled according to the droplet ejection direction. It can be anything. Further, the printing time is shorter than that in the case where there is only one substrate 3 as in the first embodiment. Therefore, when the droplet ejector according to the third embodiment is used in a printing device such as a printer, printing time is shortened.

Fourth Embodiment 15, 16 and 1
7 shows the relationship between the droplet ejection direction of the droplet ejector of the fourth embodiment and the amplitude of the drive signal. FIG. 15 shows the case where the ejection direction of the droplet 10 is perpendicular to the ink surface 2. , Figure 1
6 shows a state in which it is inclined rightward by θ1 from the direction perpendicular to the ink surface 2, and FIG. 17 shows a state in which it is further inclined rightward by θ2.

As shown in FIG. 15, when the ejection direction of the liquid droplet 10 is perpendicular to the ink liquid surface 2, the drive signals 12a, 1
The phase difference of 2b is 0 degree, and the drive signal 12 at that time is
The amplitude of a and 12b is Va, and the ejection speed of the droplet 10 is v
However, normally, when the ejection direction is tilted from the vertical direction, the ejection speed of the droplet 10 becomes slower than v, and the ejection momentum becomes weaker as the ejection direction is inclined. The droplet ejector according to the fourth embodiment is made to solve the above-mentioned problem, and an amplifier (not shown) is provided as the ejection angle of the droplet 10 with respect to the direction perpendicular to the ink surface 2 increases. The amplifier is characterized in that the amplitude of the drive signals 12a and 12b is increased.

In the fourth embodiment, as shown in FIGS. 16 and 17, the amplitude when the phase difference between the drive signals 12a and 12b is 45 degrees is Vb (> Va), and the phase difference is 90 degrees. By setting the amplitude at this time to Vc (> Vb) and increasing the amplitudes of the drive signals 12a and 12b to Vb and Vc as the inclination of the droplet 10 in the ejection direction increases to θ1 and θ2, the ejection direction is increased. As the inclination of the droplets increases, the vibration amplitude of the oscillators 4 and 5 increases, so that the droplet 10
The discharge speed v is constant regardless of the inclination of the discharge direction. As a result, even if the ejection direction is tilted, the ejection speed of the liquid droplets does not decrease, and the effect of reliably adhering to the recording paper (not shown) can be obtained.

Embodiment 5 Usually, when the diameter of the droplet is reduced, it is common to increase the drive frequency of the drive signal. The droplet ejector of the fifth embodiment is intended to obtain a droplet ejector capable of reducing the diameter of a droplet without increasing the driving frequency of ultrasonic waves.
Specifically, a member having a hole smaller than the diameter of the droplet is provided above the ink surface in order to reduce the diameter of the droplet without increasing the driving frequency of the driving signal.

FIG. 18 is a diagram showing a droplet ejector of the fifth embodiment, and is a sectional view of the droplet ejector of the fifth embodiment. In FIG. 18, 2 is an ink liquid surface, 3 is a substrate, 4a and 4b are oscillators, 7 is an acoustic lens, 8 is a focused ultrasonic wave, and 9 is a focused point of the focused ultrasonic wave 8.

Reference numeral 22 is a nozzle plate which is a member arranged on the ink surface 2. 23 is the nozzle plate 22
Hole of diameter D1 opened in the nozzle, 24 is the nozzle plate 22
It is a droplet whose diameter is narrowed by. The diameter D1 of the hole 23 is smaller than the diameter of the droplet 10 ejected from the ink surface 2 when the nozzle plate 22 is not provided.

First, the ultrasonic waves (not shown) generated by the vibrators 4a and 4b propagate in the substrate 3 and the acoustic lens 7
It is refracted by and becomes focused ultrasound 8 and is focused on a focus point 9. The hole 23 of the nozzle plate 22 has a focal point 9
The diameter D1 of the hole 23 is
Is smaller than the diameter of the droplet to be ejected, the droplet 24 with a small diameter is ejected. Thus, by using the nozzle plate 22, the vibrators 4a, 4a,
It is possible to reduce the droplet diameter without increasing the drive frequency of b. Further, by arranging the nozzle plate 22 on the ink liquid surface 2, it is possible to suppress the shaking of the ink liquid surface 2 due to the focusing of the focused ultrasonic waves.

Further, the nozzle plate 22 shown in FIG.
Although the hole 23 has a straight shape, it may be configured as shown in FIG. FIG. 19 is a view showing an example of a member having holes, and shows a cross-sectional view of the nozzle plate 22.
In FIG. 19, 25a, 25b, and 25c are holes formed in the nozzle plate 23. FIG. 19 (a),
The holes 25a, 25b, 25c shown in (b) and (c) are all holes on the outlet side (that is, the holes 25a, 25b, 25c formed on the side where the droplets pass through the nozzle plate 22 and exit) and have a diameter D1. The diameter is smaller than the diameter of a droplet discharged when the nozzle plate 22 is not provided. Further, the diameter D2 of the hole on the inlet side (that is, the holes 25a, 25b, 25c formed on the side where the droplets ejected from the ink surface 2 enter the nozzle plate 22) is D.
Greater than 1.

The hole 25a shown in FIG. 19A has a tapered shape, the hole 25b in FIG. 19B has a step shape, and the hole 25c in FIG. 19C has a horn shape. Also, the inlet side is wide and the focused ultrasonic waves 8 are easily focused. Even with the configuration shown in FIG. 19, since the diameter of the hole on the outlet side is smaller than the diameter of the droplet discharged without the nozzle plate 22, it is possible to reduce the diameter of the droplet without increasing the driving frequency. It will be possible. In addition to the shape shown in FIG. 19, any shape may be used as long as the diameter of the hole is reduced from the inlet side toward the outlet side.

Embodiment 6 FIG. The droplet ejector according to the sixth embodiment can reduce the diameter of the droplet without increasing the driving frequency of the ultrasonic wave, and due to the error in the processing accuracy of the acoustic lens and the positioning accuracy of the nozzle plate, the droplet ejector The purpose of the present invention is to obtain a droplet ejector that can squeeze the droplet to a small size even if the position where the droplets are ejected is shifted. It is characterized by being opened. FIG. 20 is a diagram for explaining the droplet ejector of the sixth embodiment, and is a perspective view of the droplet ejector. In FIG. 20, 24 is a droplet discharged from the ink surface 2.
Reference numeral 26 is a nozzle plate which is a member arranged above the ink surface 2. 27 is a nozzle slit which is a slit opened in the nozzle plate 22. The nozzle slit 27 is rectangular, and its length in the lateral direction is
The diameter is smaller than the diameter of a droplet discharged from the ink surface 2 when the nozzle slit 27 is not provided.

When positioning the nozzle plate 26, a margin is secured in the longitudinal direction of the nozzle slit 27, and positioning can be performed easily. Therefore, as in the fifth embodiment, the diameter of the droplet can be reduced, and in addition, the ejection position of the droplet is displaced due to an error in the processing accuracy of the acoustic lens 7 and the positioning accuracy of the nozzle plate 26. However, the diameter of the droplet can be narrowed. It is also possible to change the ejection direction of the droplet 24.

FIG. 21 is a diagram showing another example of the droplet ejector of the sixth embodiment, in which a member having nozzle slits is arranged above the droplet ejector in which the substrates are arranged in a predetermined direction. FIG. In FIG. 21, 3a, 3b, 3c, 3d, 3e, and 3f are substrates and 24
Reference numerals a, 24b, 24c, 24d, 24e, and 24f denote droplets discharged from the ink liquid surface 2, and 28 denotes a nozzle plate which is a member provided on the ink liquid surface 2. Reference numeral 29 is a nozzle slit formed in the nozzle plate 28. The nozzle slit 29 has a rectangular shape, and its length in the lateral direction is
The diameter is smaller than the diameter of a droplet discharged from the ink surface 2 when the nozzle slit 29 is not provided. In addition, the nozzle slit 2
The longitudinal direction of 9 and the direction in which the substrates 3a to 3f are arranged are the same.

A plurality of substrates 3a to 3f are arranged in a line to form an array, and nozzle slits 29 are formed on the nozzle plate 28 so as to cover all the ejection positions of the liquid droplets 24a to 24f according to the arrangement direction. By providing the, the nozzle plate can be easily processed and positioned when the substrates are arranged in a predetermined direction.

Seventh Embodiment If the aperture of the acoustic lens is smaller than the thickness of the substrate, the aperture of the acoustic lens becomes smaller as the substrate becomes thinner. The aperture ratio (the ratio of the area of the acoustic lens to the area of the first surface) of the acoustic lens also becomes small. When the aperture ratio of the acoustic lens formed on the substrate also decreases, the ratio of focused ultrasonic waves refracted by the acoustic lens to ultrasonic waves propagating in the substrate also decreases. Therefore, the energy given to the liquid droplets ejected from the ink liquid surface becomes small, and in the worst case, the liquid droplets are not ejected from the ink liquid surface. The droplet ejector according to the seventh embodiment has been made to solve the above-described problem, and when the thickness of the substrate is reduced, the aperture ratio of the acoustic lens formed on the surface of the substrate is increased. With this configuration, the energy loss when converting the energy applied to the vibrator to the energy of the liquid droplets ejected from the ink surface is reduced (hereinafter referred to as driving efficiency enhancement). It is characterized by.

FIG. 22 is a diagram for explaining the droplet ejector of the seventh embodiment, and is a perspective view of the substrate and the acoustic lens of the droplet ejector. 23 is a diagram for explaining the droplet ejector of the seventh embodiment, and is a top view and a front view of the substrate and the acoustic lens shown in FIG. FIG.
In FIG. 2 and FIG. 23, 30 is a substrate of the droplet ejector. The substrate 30 is a plate-shaped member that is a rectangular parallelepiped and has a thin thickness. Reference numeral 31 is an acoustic lens formed on the upper surface which is the first surface of the substrate 30. The upper surface, which is the first surface, and the lower surface, which is the second surface, are in a parallel positional relationship. Substrate 30
The shape of the cross section parallel to the upper surface that is the first surface is a rectangle having long sides a and short sides b. The acoustic lens 31 has a shape formed by a part of a spherical surface, and its radius of curvature is R1. The diameter D3 of the acoustic lens 31 is larger than b and is a.
It is configured to be smaller.

Since the droplet ejector according to the seventh embodiment has the above-mentioned structure, the aperture of the acoustic lens is increased with respect to the cross section of the substrate 30.
Driving efficiency is improved. When the F number of the acoustic lens is F, there is a relationship of F = f / D (f: focal length, D: aperture of acoustic lens). The smaller the value of F, the smaller the diameter of the droplet. The focal length f depends on the radius of curvature R of the acoustic lens. Therefore, when the curvature radius R is the same (that is, f is the same), the value of F is the aperture diameter D of the acoustic lens.
Depends on. Therefore, since the droplet ejector of the seventh embodiment has a larger aperture of the acoustic lens, the aperture of the acoustic lens is smaller than the short side b of the rectangle, and the radius of curvature R thereof is the same as that of the present embodiment. Is smaller, the diameter of the droplet can be smaller. Further, when the substrate of the droplet ejector of the seventh embodiment is used and a plurality of the substrates are arranged in a predetermined direction, the size becomes smaller. Further, configuring the printing apparatus using the droplet ejector of the seventh embodiment contributes to power saving.

24 and 25 are views for explaining another example of the seventh embodiment, and are perspective views of the substrate of the droplet ejector and the acoustic lens, and FIG. 25 is a three-view drawing thereof. In FIGS. 24 and 25, 30 is a substrate of the droplet ejector. The substrate 30 is, for example, a plate-shaped member that is a rectangular parallelepiped and has a thin thickness. 32 is the first of the substrate 30
It is an acoustic lens formed on the upper surface which is the surface. The upper surface, which is the first surface, and the lower surface, which is the second surface, are in a parallel positional relationship. The shape of the cross section parallel to the upper surface which is the first surface of the substrate 30 is a rectangle having long sides a and short sides b. The shape of the acoustic lens 32 is formed by a part of a spherical surface, and the radius of curvature thereof is R2. Further, the acoustic lens 32 is configured such that the diameter D4 thereof is larger than a (here, the length of a rectangular diagonal line). As described above, since the diameter of the acoustic lens 32 is large with respect to the cross section of the substrate 30,
The aperture ratio is higher than that shown in FIG. 23 and the driving efficiency is better. When the printing apparatus is configured using the droplet ejector shown in FIGS. 23 to 25, it is possible to obtain a small-sized and power-saving printing apparatus.

FIG. 26 is a top view and a front view when a plurality of the substrates shown in FIG. 22 are arranged side by side along a predetermined direction to form a droplet ejector. In FIG. 26, 30a, 30b, 30c, 30d, 30e, 30
f, 30g, 30h are substrates, 31a, 31b, 31c,
31d, 31e, 31f, 31g and 31h are substrates 30a
Acoustic lenses 34a, 34b, 34c, 34d, 34e formed on the upper surface, which is the first surface of each of
34f, 34g, and 34h are the focal points corresponding to each of the acoustic lenses 31a to 31h. By arranging the substrates 30a to 30h along a predetermined direction (here, along the straight line PP), the focusing points 34a to 34h are located on the straight line PP.

Since the droplet ejector shown in FIG. 26 is arranged in a line with the substrate of the droplet ejector shown in FIG. 22 lying side by side, the focal points 34a to 3h of the acoustic lenses 31a to 31h are arranged on the straight line PP.
4h are lined up to form a line head. Therefore, the substrate 30a ...
The droplet ejector in which 30h is arranged in the ink has a wider printing range without changing the relative position of the recording paper and the droplet ejector, and shortens the printing time. Further, since the substrates 30a to 30h are arranged side by side, a thin and smart line head can be constructed.

Further, the resolution can be further increased by controlling the discharge direction of the liquid droplets. The line heads are stacked in three stages, and yellow, magenta, and cyan inks are supplied to the respective columns to supply color lines. It can also be a head.

FIG. 27 is a top view and a side view when a plurality of the substrates shown in FIG. 22 are arranged vertically in a predetermined direction to form a droplet ejector. In FIG. 27, 30i, 30j, 30k, 30l, 30m and 30n are substrates, 31i, 31j, 31k, 31l, 31m and 31n.
Is an acoustic lens formed on the upper surface which is the first surface of each of 30i to 30n, 34i, 34j, 34k, 34l,
34m and 34n are the focal points corresponding to each of the acoustic lenses 31i to 31n. The droplet ejector of FIG. 27 is shown in FIG.
The substrate of the droplet ejector shown in FIG. 2 is vertically arranged and arranged in a predetermined direction. By arranging the substrates 30a to 30n along a predetermined direction (here, along the straight line QQ), the focal points 34a to 3 of the acoustic lenses 31a to 31n.
A line head is constructed such that 4n is located on the straight line QQ.

Further, since the line head is constructed by vertically arranging the substrates 30a to 30n, the intervals between the focal points are narrowed, so that the resolution is increased. Further, since the substrates 30a to 30n are arranged vertically, it is possible to eject droplets on a plurality of lines at once. Further, as shown in FIGS. 26 and 27, when a droplet ejector in which a plurality of substrates are arranged in a predetermined direction is configured, the space efficiency is improved, and the droplet ejector array can be made smaller. it can. Although the substrate shown in FIG. 22 is used in the droplet ejector of FIGS. 26 and 27, the same effect can be obtained by using the substrate shown in FIG. It can be further reduced.

FIG. 28 is a diagram for explaining another example in which a plurality of the substrates shown in FIG. 22 are arranged along a predetermined direction. The droplet ejector of FIG. 28 is obtained by vertically aligning the substrates 30a to 30c of the droplet ejector of FIG. 22 and arranging three vertically along a predetermined direction. Thereby, the focal points 36a, 36b, 36 of the acoustic lenses 35a, 35b, 35c are
c comes to be located on a straight line. Acoustic lens 35a
Is yellow (Y) ink (not shown), and the acoustic lens 35b is magenta (M) ink (not shown).
By supplying cyan (C) ink (not shown) to the acoustic lens 35c, a color serial type head can be formed.

Then, by moving this in the direction of the arrow shown in FIG. 28 and scanning the droplets ejected from each droplet ejector perpendicularly to the traveling direction, a plurality of lines can be printed at a time. Printing time is reduced. Therefore, when the printing apparatus is configured by using the droplet ejector shown in FIG. 28, a printing apparatus capable of color printing and having a short printing time can be obtained. Although the substrate shown in FIG. 22 is used in FIG. 28, the same effect can be obtained by using the substrate shown in FIG.

Embodiment 8 FIG. In the droplet ejector in which the plurality of substrates are arranged along the predetermined direction in the above-described embodiments, when the substrates are arranged sideways, the distance between the focal points of the acoustic lenses is a substrate having a rectangular cross section. Could not be shorter than the length in the longitudinal direction. Also,
When the substrates were arranged vertically, the distance between the focal points of the acoustic lenses could not be made shorter than the length in the lateral direction of the substrate having a rectangular cross section. In the droplet ejector according to the eighth embodiment, the distance between the focal points of each acoustic lens is longer than the length in the longitudinal direction or the lateral direction of the substrate depending on the arrangement direction of the substrates having a rectangular cross section. It is characterized in that it is configured to be short.

FIG. 29 is a diagram showing a droplet ejector of the eighth embodiment, and is a top view and a side view of a substrate of the droplet ejector of the eighth embodiment. In FIG. 29, 37 is a substrate, and the substrate 37 is, for example, a rectangular parallelepiped and is a thin plate member. Reference numeral 38 is an acoustic lens formed on the upper surface which is the first surface of the substrate 37. Reference numeral 39 is the focus of the acoustic lens 38. The upper surface, which is the first surface, and the lower surface, which is the second surface, are in a parallel positional relationship. The shape of the cross section parallel to the upper surface that is the first surface of the substrate 37 is a rectangle having a long side length a and a short side length b. The shape of the acoustic lens 38 is formed by a part of a spherical surface, and the radius of curvature thereof is R3. Further, the diameter D5 of the acoustic lens 38 is configured to be larger than b and smaller than a. The center of the diameter of the acoustic lens 38 is located at the midpoint of the long side of the above rectangle. Therefore, the focal point 39 of the acoustic lens 38 is located on the straight line which passes through the midpoint of the long side of the above rectangle and is perpendicular to the upper surface.

Since the droplet ejector in FIG. 29 is configured as described above, the aperture of the acoustic lens 38 is larger than the cross section of the substrate 37 as in the droplet ejector shown in FIGS. 22 and 23 of the seventh embodiment. When taken, the aperture ratio increases and the driving efficiency increases. Further, when a plurality of substrates of the droplet ejector of the eighth embodiment are arranged along a predetermined direction, the volume of the substrate becomes small, so that the droplet ejector can be made smaller.

FIG. 30 is a diagram when a plurality of the substrates shown in FIG. 29 are arranged along a predetermined direction to form a droplet ejector. The plurality of substrates shown in FIG. 29 are arranged in a predetermined direction. FIG. 3 is a top view and a front view of the droplet ejectors arranged along the line. In FIG. 30, 37a, 37b, 37c, 37
d, 37e, 37f, 37g, 37h, 37i, 37j
And 37k are the substrates shown in FIG. 29, 38a, 38b,
38c, 38d, 38e, 38f, 38g, 38h, 3
Reference numerals 8i, 38j, and 38k denote acoustic lenses formed on the upper surface which is the first surface of each of the substrates 37a to 37j. In FIG. 30, 39a, 39b, 39c, 39
d, 39e, 39f, 39g, 39h, 39i, 39j
And 39k are the focal points of each of the acoustic lenses 38a to 38k. The droplet ejector of FIG. 30 is obtained by using the substrate of the droplet ejector shown in FIG. 29 as the focal point 3 of the acoustic lenses 38a to 38k.
9a to 39k are arranged side by side in two rows so as to be arranged on the straight line SS. As a result, FIG.
The droplet ejector of (1) constitutes a line head in which the focal points 39a to 39k are arranged on the straight line SS.

With the above arrangement, the distance between adjacent focal points can be halved as compared with the case where the substrates are arranged side by side in a line. Therefore, the substrates are arranged side by side in a line. It is possible to obtain double the resolution as compared with the case of using the same method. Further, the resolution can be further increased by controlling the droplet discharge direction.

FIG. 31 shows another example of the droplet ejector of the eighth embodiment, and is a top view and a side view of the substrate of the droplet ejector. FIG. 31 is a top view and a side view of the substrate of the droplet ejector and the acoustic lens. In FIG. 31, reference numeral 40 denotes a substrate, and the substrate 40 is, for example, a rectangular parallelepiped and is a thin plate-shaped member. Reference numeral 41 is an acoustic lens formed on the upper surface which is the first surface of the substrate 37. 42 is the focus of the acoustic lens 41. The upper surface, which is the first surface, and the lower surface, which is the second surface, are in a parallel positional relationship. The shape of the cross section parallel to the upper surface which is the first surface of the substrate 40 is a rectangle having a long side length a and a short side length b. The acoustic lens 41 has a shape formed by a part of a spherical surface, and has a radius of curvature of R4.

Further, the diameter D6 of the acoustic lens 41 is configured to be larger than a. The center of the diameter of the acoustic lens 41 is located at the midpoint of the short side of the above rectangle. Therefore,
The focal point 42 of the acoustic lens 41 is located on a straight line which passes through the midpoint of the short side of the above rectangle and is perpendicular to the upper surface.

Since the droplet ejector shown in FIG. 31 is constructed as described above, the acoustic lens 4 is attached to the cross section of the substrate 40.
Since the diameter of No. 2 is made larger than that shown in FIG. 29, the aperture ratio is increased and the driving efficiency is increased. Further, when a plurality of substrates 40 of the droplet ejector of the eighth embodiment are arranged along a predetermined direction, the volume of the substrate becomes small, so that the droplet ejector can be made smaller.

FIG. 32 is a view showing an example in which a plurality of substrates of the droplet ejector of FIG. 31 are arranged along a predetermined direction to form a droplet ejector. In FIG. 32, 40
a, 40b, 40c, 40d, 40e and 40f are substrates, 41a, 41b, 41c, 41d, 41e and 4
Reference numeral 1f is an acoustic lens formed on the upper surface which is the first surface of each of the substrates 40a to 40f. 42a, 42b, 4
2c, 42d, 42e and 42f are acoustic lenses 41a
Each is the focus of ~ 41p. The droplet ejector shown in FIG. 31 is replaced with acoustic lenses 41a to 41f in the same manner as in FIG.
Of the substrate 4 so that the focal points 42a to 42f thereof are aligned on the straight line TT.
0a to 40f are arranged side by side in two rows alternately up and down, and focusing points 42a to 42f are arranged on a straight line TT to form a line head.

With the above structure, the distance between adjacent focal points can be reduced by half compared to the case where the substrates are arranged vertically in one line. Therefore, the substrates are arranged vertically in one line and arrayed. It is possible to obtain double the resolution as compared with the case of using the same method. Further, the resolution can be further increased by controlling the droplet discharge direction.

Embodiment 9 FIG. FIG. 33 is a perspective view of the droplet ejector of the ninth embodiment. In FIG. 33, 4
Reference numerals a, 4b, 4c, 4d, 4e, 4f, 4g, 4h and 4i are vibrators. 300 is located in the ink (that is, located below the liquid surface 2 of the ink), and the vibrators 4a to 4i are provided.
Is a member for propagating ultrasonic waves generated by the vibration toward the acoustic lens 7, and the member 300 is, for example, a rectangular parallelepiped member. Here, the case where the member 300 is a rectangular parallelepiped (or a cube) will be described as an example. The acoustic lens 7 is formed on the upper surface that is the first surface of the member 300.
Further, the vibrators 4a to 4i are arranged in a lattice pattern on the lower surface which is the second surface facing the upper surface which is the first surface.

Next, the operation of the droplet ejector of the ninth embodiment will be described. The plurality of ultrasonic waves having the same drive frequency emitted by the vibrators 4a to 4i are focused by the acoustic lens 7 at the focal point 9 on the ink surface 2. At this time, if the phase difference between the ultrasonic waves is zero, the droplet 10 is ejected in a direction perpendicular to the ink surface 2. By providing an appropriate phase difference for each drive signal applied to the vibrators 4a to 4i, the ejection direction of the droplet 10 at the focusing point 9 can be freely controlled.

As a result, the droplet 10 can be attached to a predetermined plane of the recording paper (not shown) with one droplet ejector. Therefore, it is possible to print a range on a specific plane with one droplet ejector without changing the relative positions of the droplet ejector and the recording paper. Further, by arranging the members 300 along the predetermined direction, the printable range can be widened and the printing time can be shortened without changing the relative positions of the droplet ejector and the recording paper.

Embodiment 10 FIG. The present embodiment is characterized in that the printing apparatus is configured using the droplet ejector shown in the first to ninth embodiments. FIG. 34 is a block diagram for explaining the printing apparatus according to the tenth embodiment. In FIG. 34, 700 is a printing apparatus. 701
Is a part of the components of the printing apparatus 700, and is a paper feeding means for feeding a recording paper (not shown). 702
Is a part of the components of the printing apparatus 700, and is a conveyance unit that conveys the recording paper supplied by the paper supply unit 701 to a predetermined position. Reference numeral 703 denotes a part of the components of the printing apparatus 700, which is a printing unit that attaches droplets to a predetermined position on the recording paper that has been conveyed to a predetermined position by the conveyance unit 702 and prints the droplet. Reference numeral 704 denotes a part of the components of the printing apparatus 700, which is a paper ejection unit for ejecting the printed recording paper after the printing by the printing unit 703 is completed.

Reference numeral 7031 denotes a part of the components of the printing unit 703, which is shown in any one of the first to ninth embodiments.
Alternatively, a droplet ejector is formed by appropriately combining these. Reference numeral 7032 is a part of the components of the printing unit 703, and is a receiving unit that receives a signal notifying the printing unit 703 that the recording medium has been conveyed to a predetermined position by the conveying unit 702. The receiving unit 7032 is the conveying unit. Receives a signal notifying that the recording paper has been conveyed to a predetermined position, it sends a signal for operating the droplet ejector 7031 to the droplet ejector 7031.

The operation of the printing apparatus shown in FIG. 34 will be described. First, when the printing apparatus 700 receives a signal for printing from a device such as a computer (not shown), the sheet feeding unit 701 sends the recording sheet to the conveying unit 702. The transport unit 702 transports the received recording paper to a predetermined position. In the printing unit 703, the receiving unit 70 receives a signal notifying that the conveying unit 702 has conveyed the recording paper to a predetermined position.
When 32 receives the droplet ejector 7031,
A droplet is attached to a predetermined position on a predetermined straight line or a predetermined plane. The printing unit 703 is a droplet ejector 7031.
When the droplets have adhered to the predetermined straight line or the predetermined flat surface of the recording paper, the position of the conveying means 702 or the droplet ejector 7031 is moved, so that the recording paper and the droplet ejector 7031 are relatively moved. After changing the position, the droplet ejector is operated again to attach the droplets to the recording paper. The above-described operation is continued until the droplets are attached to all predetermined positions on the recording paper, and when the attachment of the droplets is completed, a print end signal is sent to the paper discharge unit 704. The paper discharge unit 704 discharges the recording paper after receiving the print end signal.

FIG. 35 is an example of a block diagram for realizing the block diagram of the printing apparatus of FIG. In FIG. 35,
Reference numeral 10 is a droplet ejected from the droplet ejector 7031, and 80
Reference numeral 0 is a recording paper to which the droplet 10 is attached. Reference numeral 701 denotes a roller that is a paper feeding unit, and 7021 is a part of the constituent elements of the conveyance unit 702, which is a recording paper 800 and a droplet ejector 703.
It is a roller for changing the position relative to 1. 7
Reference numeral 022 denotes a position detection unit that is a part of the constituent elements of the conveyance unit 702 and that detects the position of the recording paper. A roller 704 is a sheet discharging unit.

The operation of the printing apparatus shown in FIG. 35 will be described. First, when a printing device receives a signal for printing from a device such as a computer (not shown), the roller 7
01 sends the recording paper 800 to the conveying means 702. The transport unit 702 transfers the received recording paper 800 to a roller 7021.
Is conveyed to a predetermined position. Position detecting means 7022
When the recording paper 800 is conveyed to a predetermined position, sends a signal notifying that the recording paper 800 has been conveyed to the predetermined position to the receiving means 7032. In the printing unit 703, when the receiving unit 7032 receives the signal sent from the position detecting unit 7022 to the receiving unit 7032, the droplet ejector 7031 is operated to attach the droplet 10 to a predetermined position on a predetermined straight line or a predetermined plane. Let When the droplet ejector 7031 finishes depositing the droplet 10 on a predetermined straight line or a predetermined plane of the recording paper 800, the printing unit 703 causes the roller 702.
1, or by moving the position of the droplet ejector 7031, the relative positions of the recording paper 800 and the droplet ejector 7031 are changed, and then the droplet ejector 7031 is operated again to attach the droplet 10 to the recording paper 800. . The above operation is continued until the droplets are attached to all the predetermined positions of the recording paper 800, and when the attachment of the droplets 10 is completed, the roller 7
A print end signal is sent to 04. The roller 704 ejects the recording paper 800 after receiving the print end signal.

The printing apparatus shown in FIGS. 34 and 35 is the first embodiment.
Since any one of the droplet ejectors shown in Nos. 9 to 9 is included, the resolution and reliability are high. In addition, printing time is shortened by using a droplet ejector in which a plurality of substrates 3 are arranged along a predetermined direction. Further, by using the droplet ejector in which the vibrators are arranged in a grid pattern on the second surface, it becomes possible to print on a predetermined plane without changing the relative positions of the recording paper and the droplet ejector. , The printable range becomes large.

[0112]

Since the present invention is configured as described above, it has the following effects.

The droplet ejector of the present invention can adjust the ejection direction of the droplet ejected from the vicinity of the focal point of the acoustic lens by adjusting the phase in which at least two of the plurality of vibrators vibrate. Therefore, the ejection direction of the droplet can be controlled, and since the acoustic lens is provided, the ejection position of the droplet does not deviate from the focus of the acoustic lens, so that the resolution becomes high. Moreover, the number of parts is small and the configuration is simple.

Since the droplet ejector of the present invention has a plurality of members and the plurality of members are arranged in a predetermined direction, printing can be performed without changing the relative positions of the recording paper and the droplet ejector. The range that can be widened,
Printing time is shortened.

In the droplet ejector of the present invention, since a plurality of vibrators are arranged in a grid, one droplet ejector does not change the relative position between the droplet ejector and the recording paper, and a range on a specific plane is obtained. Can be printed.

In the droplet ejector of the present invention, since a plurality of vibrators are arranged in a predetermined direction, it becomes possible to attach the liquid drops to the recording paper along the direction in which the vibrators are arranged.

The droplet ejector of the present invention comprises the first member
The surface is rectangular and the aperture of the acoustic lens formed on the first surface is larger than the length of the short side of the rectangle. Therefore, the aperture ratio of the acoustic lens is high, and the driving efficiency is high.

In the droplet ejector of the present invention, the members whose acoustic lens center is located at the midpoint of the short side of the rectangle are arranged alternately in two rows so that the center of the aperture is located on a predetermined straight line. Since the distance between the focal points of the adjacent acoustic lenses becomes short, the resolution becomes high.

In the droplet ejector of the present invention, the members in which the center of the diameter of the acoustic lens is located at the midpoint of the long side of the rectangle are alternately arranged in two rows so that the center of the diameter is located on a predetermined straight line. Since the distance between the focal points of the adjacent acoustic lenses becomes short, the resolution becomes high.

The droplet ejector of the present invention synchronizes the phase change of the drive signal for driving the plurality of vibrators arranged in each member, and synchronizes the phase of the drive signal for driving the plurality of vibrators arranged in each member. By periodically changing and controlling the drive of each transducer according to the image signal, the droplets are selectively ejected, which shortens the printing time.

In the droplet ejector of the present invention, since the slits are formed so as to separate the individual ultrasonic waves generated by the vibration of the individual vibrators, the ultrasonic waves propagating in the substrate do not interfere with each other, and There is no risk that the direction in which the droplets are ejected deviates from the designed direction.

Since the droplet ejector of the present invention is constructed so that the amplitude of the drive signal for driving the vibrators is increased as the phase difference between the plurality of vibrators is increased, the speed at which the droplets are ejected becomes constant. Therefore, even if the ejection angle of the droplet is increased, the droplet is surely attached to the recording paper.

In the droplet ejector of the present invention, since a member having a hole having a diameter smaller than the diameter of the droplet is arranged on the liquid surface of the ink at the position where the focus of the acoustic lens is formed, the ejection is performed. It is possible to reduce the diameter of the droplet to be formed.
Further, since the member is arranged on the ink liquid surface, the fluctuation of the liquid surface is suppressed.

In the droplet ejector of the present invention, since the member having the slit having the width smaller than the diameter of the droplet is arranged on the liquid surface of the ink at the position where the focus of the acoustic lens is provided, the liquid ejector The diameter of the droplet can be reduced, and the ejection direction of the droplet 24 can be changed. Also, positioning during assembly becomes easy. Further, since the member is arranged on the ink liquid surface, the fluctuation of the liquid surface is suppressed.

In the printer of the present invention, the angle of the droplet ejected from the vicinity of the focal point of the acoustic lens is adjusted by adjusting the phase in which at least two of the plurality of transducers vibrate in the droplet ejector. Since a droplet ejector capable of adjusting the liquid droplet ejector is used, the ejection direction of the droplet can be controlled, and the ejection position of the droplet does not deviate from the focus of the acoustic lens, resulting in high resolution.

Since the printing apparatus of the present invention uses the droplet ejector having a plurality of members and the plurality of members arranged in a predetermined direction, the recording paper and the droplet ejector are relatively disposed. The printing range becomes wider and the printing time becomes shorter without changing the position.

[Brief description of drawings]

FIG. 1 is a diagram showing a droplet ejector according to a first embodiment.

FIG. 2 is a diagram showing an example of an input signal of the droplet ejector according to the first embodiment.

FIG. 3 is a diagram showing an example of a drive signal in the droplet ejector according to the first embodiment.

FIG. 4 is a diagram showing the operation of the droplet ejector according to the first embodiment.

5 is a diagram showing an example of a drive signal input to the droplet ejector shown in FIG. 4 in the droplet ejector of the first embodiment.

FIG. 6 is a diagram showing an example of the operation of the droplet ejector according to the first embodiment.

7 is a diagram showing an example of a drive signal input to the droplet ejector shown in FIG. 6 in the droplet ejector according to the first embodiment.

FIG. 8 is a diagram for explaining a method of controlling the ejection direction of droplets in the droplet ejector according to the first embodiment.

9 shows an input signal of the droplet ejector shown in FIG.

FIG. 10 is a diagram showing a droplet ejector according to a second embodiment.

FIG. 11 is a diagram showing another example of the droplet ejector shown in the second embodiment.

FIG. 12 is a diagram showing another example of the droplet ejector shown in the second embodiment.

FIG. 13 is a diagram showing a droplet ejector according to a third embodiment.

FIG. 14 is a diagram showing an operation of the droplet ejector according to the third embodiment.

FIG. 15 is a diagram showing the relationship between the droplet ejection direction and the drive voltage of the droplet ejector according to the fourth embodiment.

FIG. 16 is a diagram showing a relationship between a droplet ejection direction and a drive voltage of the droplet ejector according to the fourth embodiment.

FIG. 17 is a diagram showing the relationship between the droplet ejection direction and the drive voltage of the droplet ejector according to the fourth embodiment.

FIG. 18 is a diagram showing a droplet ejector according to a fifth embodiment.

FIG. 19 shows a droplet ejector according to a fifth embodiment,
It is a figure which shows an example of the member which has a hole.

FIG. 20 is a perspective view of a droplet ejector according to a sixth embodiment.

FIG. 21 is a perspective view of a droplet ejector according to a sixth embodiment.

FIG. 22 is a perspective view showing a droplet ejector according to a seventh embodiment.

FIG. 23 is a top view and a front view showing a droplet ejector according to a seventh embodiment.

FIG. 24 is a perspective view showing a modified example of the droplet ejector of the seventh embodiment.

FIG. 25 is a trihedral view showing a modified example of the droplet ejector of the seventh embodiment.

FIG. 26 is a diagram when a plurality of substrates are arranged in a predetermined direction in the droplet ejector of the seventh embodiment.

FIG. 27 is a diagram when a plurality of substrates are arranged in a predetermined direction in the droplet ejector of the seventh embodiment.

FIG. 28 is a diagram showing a plurality of substrates arranged in a predetermined direction in the droplet ejector according to the seventh embodiment.

FIG. 29 is a diagram showing a droplet ejector according to an eighth embodiment.

FIG. 30 is a droplet ejector of the eighth embodiment,
It is a figure when a plurality of substrates are arranged along a predetermined direction.

FIG. 31 is a diagram showing another example of the droplet ejector of the eighth embodiment.

FIG. 32 is a droplet ejector of the eighth embodiment,
It is a figure when a plurality of substrates are arranged along a predetermined direction.

FIG. 33 is a perspective view showing a droplet ejector of the ninth embodiment.

FIG. 34 is a block diagram illustrating a printing apparatus according to the tenth embodiment.

FIG. 35 is a configuration diagram illustrating a printing apparatus according to a tenth embodiment.

FIG. 36 is a cross-sectional view showing a conventional droplet ejector.

FIG. 37 is a cross-sectional view showing a conventional droplet ejector.

FIG. 38 is a cross-sectional view showing a conventional droplet ejector.

FIG. 39 is a cross-sectional view showing a conventional droplet ejector.

[Explanation of symbols]

1 Ink 2 Ink Liquid Level 3 Substrate 4a, 4b Transducer 5a, 5b Lead 6a, 6b Ultrasonic 7 Acoustic Lens 8a, 8b Focused Ultrasonic 9 Focusing Point 10 Droplet 11a, 11b Burst Signal 12a, 12b Drive Signal 12c, 12d , 12e, 12f, 12g Drive signal 13a, 13b, 13c, 13d, 13e Slit 19 Image signal 22, 28 Nozzle plate 23 Hole 27, 29 Nozzle slit 30, 37, 40 Substrate 31, 32, 38, 41
Acoustic lens

Claims (14)

[Claims] 1. A member which is located in the ink and is arranged such that the focal point of the acoustic lens formed on the first surface is near the liquid surface of the ink and propagates through the member toward the acoustic lens. A plurality of vibrators that generate ultrasonic waves having the same driving frequency, and the plurality of vibrators are arranged along a predetermined direction on the second surface of the member, and at least one of the plurality of vibrators is arranged. A droplet ejector characterized in that the ejection direction of droplets ejected from the vicinity of the focal point can be adjusted by adjusting the phase in which the two oscillators vibrate. 2. The droplet ejector according to claim 1, wherein a plurality of members are provided, and the plurality of members are arranged along a predetermined direction. 3. The member is a rectangular parallelepiped member, and a plurality of vibrators are arranged in a grid pattern on a second surface opposite to the first surface, according to claim 1 or 2. The droplet ejector described in 1 .. 4. The member is a plate-shaped member, and a plurality of vibrators are arranged in a predetermined direction on a second surface, which is an end surface opposite to a first surface, which is an end surface of the plate-shaped member. The droplet ejector according to claim 1 or 2, wherein the droplet ejectors are arranged. 5. The first surface of the member is rectangular and the first surface
The droplet ejector according to any one of claims 1 to 4, wherein the acoustic lens formed on the surface has a diameter larger than the length of the short side of the rectangle. 6. A member in which the center of the diameter of the acoustic lens is located at the midpoint of the short side of the first surface is arranged in two rows alternately so that the center of the diameter is located on a predetermined straight line. The droplet ejector according to claim 5, which is characterized in that: 7. A member in which the center of the diameter of the acoustic lens is located at the midpoint of the long side of the first surface is arranged in two rows alternately so that the center of the diameter is located on a predetermined straight line. The droplet ejector according to claim 5, which is characterized in that: 8. A phase change of a drive signal for driving a plurality of vibrators arranged on each member is synchronized, and a phase of a drive signal for driving a plurality of vibrators arranged on each member is periodically changed. At the same time, the liquid droplet ejector according to any one of claims 1 to 7, wherein the liquid droplets are selectively ejected by controlling the drive of each of the vibrators according to an image signal. 9. A slit is formed in the member so as to separate individual ultrasonic waves generated by vibrating the individual oscillators arranged on the second surface.
9. The droplet ejector according to any one of 1 to 8. 10. The structure according to claim 1, wherein the amplitude of a drive signal for driving these vibrators is increased as the phase difference between at least two vibrators is increased. The droplet ejector described in 1 .. 11. A member having a hole having a diameter smaller than the diameter of the droplet is provided, and the member is placed on the liquid surface of the ink so that the hole is located at a position corresponding to the focal point of the acoustic lens. The droplet ejector according to any one of claims 1 to 10, wherein the droplet ejector is arranged at 12. A member provided with a slit having a width smaller than the diameter of the liquid droplet, and the member is placed on the liquid surface of the ink so that the slit is located at a position corresponding to the focal point of the acoustic lens. It has been arranged in the.
11. The droplet ejector according to any one of 1 to 10. 13. A printing device for ejecting droplets from ink and adhering the droplets to a recording paper for printing, wherein the focal point of an acoustic lens located in the ink and formed on the first surface. A plurality of vibrators that generate ultrasonic waves with the same drive frequency propagating in the member toward the acoustic lens and a member arranged so that the position is near the liquid surface of the ink. Are arranged along a predetermined direction on the second surface of the member, and the phase at which at least two vibrators of the plurality of vibrators vibrate are adjusted, so that the liquid discharged from the vicinity of the focal point. A printing apparatus comprising a droplet ejector configured to adjust a droplet ejection direction. 14. The printing apparatus according to claim 13, wherein a plurality of members are provided, and the plurality of members are arranged in a predetermined direction.