JPS6068963A - Inkjet recorder - Google Patents

Abstract

PURPOSE:To jet small ink drops for printing each time an electrical pulse is applied for printing by forming in electro-mechanical conversion means in disk provided in a pressure chamber filled with ink corresponding to each other. CONSTITUTION:A print head 18 is made up of a housing 36 defining a part of a pressure chamber 37. Ink is fed to an inlet path 38 through a communicating tube 17 and an orifice 52 of a precise diameter is provided at the end of an outlet path 39. The upper wall of the pressure chamber 37 is made up of a pressure plate (flexible plate) 41 and two piezoelectric plates 42 and 43 composing the pressure plate 41 are both formed in a sheet-shaped disk to be joined together with a conductive thin film 44.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a non-impact recording device, and more particularly to a so-called ink jet recording device that ejects small droplets of ink from an orifice of a print head. be.

[Prior Art] Conventional non-impact recording devices use various types of devices that create information patterns (letters, numbers, symbols, shapes, etc.), and these devices are electrostatic and electrolytic.

It is often used as a type of recording device such as type, discharge type, and heat-sensitive type. However, all of these methods not only require specially treated recording media, but also require more complicated processes and special printing processing media.

Therefore, ink jet recording devices were developed to improve the drawbacks of these devices. From this 1, small droplets of ink are deposited on an untreated recording medium (hereinafter referred to as recording paper) in a predetermined 11'7 pattern (11).
It means +, commercial printing, low @ sound, plain paper history 7
In recent years, it has attracted attention as a promising recording device due to its low running cost and other features.

However, ink jet recording devices (・, high speed and low @
In order to accurately record a wide range of 1a signal patterns with sound, the ink jetting action itself must be suitable for these purposes. To this end, the flight characteristics of the ink droplets must be constantly stabilized for all ink droplets under all usage environments in order to maintain the accuracy of the information pattern.

■ Since a large number of droplets are ejected at high speed, it is desirable to avoid excessive consumption of ink.

(2) In order to perform the relative movement between the recording paper and the ink jet head at high speed and smoothly, it is desirable to make the fI of the grooves of the ink jet head as small as possible.

■ Furthermore, since it is intended for long-term use,
In addition to maintaining the reliability of the device if6 <, it is particularly desirable that the structure of the ink jet head be as simple and reliable as possible, both in terms of eliminating failures and for maintenance and inspection.

■ Naturally, it is desirable that the product be of low cost.

These conditions are desirable as basic conditions for device design. However, all currently known ink jet recording devices do not necessarily satisfy these basic conditions.

The first method of conventional ink jet recording devices is 1.
1″i Publication No. 42-8350, Special Publication No. 42-438
As described in Publication No. 1 and Japanese Patent Publication No. 44-4517, ◎ A high pressure is applied to the ink in advance to cause the ink to flow out continuously from the tip of the nozzle, and ◎ The nozzle is mechanically vibrated by a vibrator. ◎ Next, using the charging electrode installed in front of the nozzle, each ejected ink droplet is given a charge according to the information pattern, ◎ Even higher A deflection electrode plate generating a voltage electric field is placed in the flight space of the ink droplets to deflect the ink droplets passing through the constant high voltage electric field according to the amount of charge on each droplet, thereby transmitting predetermined information. A method of forming patterns on recording paper! be.

However, this method has the following drawbacks. That is, (,) a special pressure device is required to apply high continuous pressure to the ink.

(b) Since the nozzle is mechanically vibrated at high speed using a magnetostrictive vibrator or a piezoelectric vibrator, the nozzle structure becomes extremely complicated.

(C) When a column of ink ejected at high pressure from a nozzle is turned into small ink droplets by a vibrator, the ink droplets must be formed at regular time intervals and of uniform size.
Actual commercialization requires complex equipment and electrical circuits.

(d) Since a high voltage is required for the charging electrode and flilJ control is required according to the information pattern when charging the ink droplets, precision is required for the controller 11, and the device is +X′G value.

(e) The formation of ink droplets by the vibrator and the charging time of the droplets must be precisely synchronized, making the synchronization means complicated.

(f) It is necessary to apply a high voltage of several thousand volts to the deflection electrodes as well.

(g) Since charging electrodes and biasing electrodes are easily contaminated by dust and ink, the performance of the device is likely to be hindered by these substances. Therefore, countermeasures are required.

(11) Furthermore, by applying a high voltage between the nozzle and the electrode, the electrical component 11τ of the ink is generated, which produces corrosive by-products on the nozzle and the electrode, which can damage the nozzle and the electrode. Since this causes deterioration, preventive measures are required.

(i) Since the continuous ejection of ink droplets from the nozzle ejects a large number of droplets that may or may not contribute to the formation of the information pattern, these unnecessary ink can be collected and reused or disposed of. requires additional equipment.

etc. In order to overcome these shortcomings and create a highly reliable ink jet recording device based on the basic conditions mentioned above, there are still many technical problems to be solved, including the need for precise and complex equipment and electrical equipment. This requires circuitry and makes the product expensive.

The second method, as shown in Japanese Patent Publication No. 36-13768, uses deflection electrodes to deflect continuously flying ink droplets into a lory trajectory ('I'rajec lory').
) to form an information pattern is the same as the first method, except that the formation of ink droplets and the strength of the deflection electric field are changed to create an ink droplet. This method differs from the first method only in that the flying direction of the droplets is deflected.

That is, ◎ First, an acceleration electrode and a deflection electrode are respectively installed in the space of the nozzle. ◎ Next, pressure is applied to the ink so that the ink becomes a convex meniscus state at the tip of the nozzle, and ◎ By applying a constant high voltage between the acceleration electrode and the ink in the nozzle, the ink is sucked out from the nozzle by the action of this strong electrostatic field, and the flow of the sucked ink is , broken into successive ink droplets of essentially constant volume and charge.

◎ In addition, a deflection electrode provided outside the accelerating electrode is controlled in response to a human power signal to deflect the ink droplet passing through the electric field, thereby forming a predetermined information pattern on the paper. However, this method also has drawbacks comparable to the method of t51. That is, ■
Synchronization between the time when ink droplets are formed and the time when high-voltage pulses are applied;
(b) Regarding the deterioration of nozzles and electrodes due to high voltage, and the generation of unnecessary ink droplets when creating 18-report patterns using ink droplets, both
The disadvantages are the same as those of the above method, but in addition, (a) since the electrostatic suction effect of the ink is utilized, there is a limit to the droplet formation speed, making high-speed printing impossible.

(b) The device becomes expensive because it is necessary to apply a high voltage of several thousand volts between the accelerating electrode and the nozzle.

(c) Furthermore, it is necessary to provide the bias electrode with a tooth pattern of several thousand volts, and this must be changed for each ink droplet according to the information pattern, so its control is difficult. accompanied by difficulty.

etc. In order to overcome these shortcomings and complete a highly reliable ink jet recording device based on the above basic conditions, there are still many technical problems to be solved, and it is necessary to use a precise and complicated device and a highly reliable ink jet recording device. Requires electrical circuit. Furthermore, compared to the first method, there is a fundamental drawback in that high-speed printing cannot be performed.

Although this is a very special example, another method is also known. It is shown in US Pat. No. 2,512,743. According to this disclosure, an ultrasonic shock wave is continuously generated at a mechanical resonance frequency in a horn-shaped nozzle filled with ink, and the shock wave moves from a large diameter part to a small diameter part along the internal slope of the nozzle. During this process, the strength of the shock wave increases, and the bubble action of cavitation generated in the ink by this ultrasonic shock wave causes a spray of ink to be ejected from the end of the nozzle. However, this method has the following drawbacks.

(+1) The device operates at a constant speed determined by mechanical resonance.

(1) The ejection system cannot form - ink droplets in response to - electrical signals because the ejection system does not return to an equilibrium state after ejecting a -drop. The combined resonant effects of multiple signals are required for ink jetting.

(c) Since the ink is ejected in the form of a spray, it is difficult to control it to obtain a highly accurate information pattern.

For this reason, this method cannot be used as is for general-purpose ink jet recording, and improvements are desired.

Therefore, at this stage, this method cannot be considered as a method used for special purposes, and in addition, it can be said that it does not meet most of the basic conditions mentioned above.

[Object of the Invention] The object of the present invention is to provide improved printing in these ink jet recording devices so that ink droplets necessary for printing are ejected every time an electric pulse for printing is applied. An object of the present invention is to provide an ink jet recording device having a head.

[Configuration 1 of the Invention] That is, the present invention is a print head of an ink jet recording device that ejects ink droplets by deforming the internal volume of the pressure chamber by an electromechanical conversion means provided corresponding to a pressure chamber filled with ink. The electromechanical conversion means is characterized in that it has a circular plate shape.

The object of the present invention can also be effectively achieved, for example, in an ink jet recording apparatus as described below. (a) A pressure chamber in continuous communication with the oriice and the ink reservoir is swirled with ink from the ink reservoir, and the pressure chamber is configured such that at least a portion of its wall can be deformed by electromechanical conversion means. (1,) When not recording, the ink is maintained in an equilibrium state by the static pressure of the ink in the ink reservoir and the surface tension of the ink at the orifice, and (c) When the electric pulse is applied and removed, the electromechanical transducer (d) ejecting a portion of the ink in the pressure chamber from the orifice toward the recording medium by displacing the wall of the pressure chamber inward as a result of the operation; A typical example is an ink jet recording apparatus characterized in that the volume of the pressure chamber is later restored to restore the initial ink equilibrium state.

[Example] Hereinafter, the ink jet 1ift device equipped with a print head according to the present invention will be described based on the illustrated example.

Figures 1.2.3 are schematic diagrams of embodiments for explaining the principle of an ink jet recording apparatus to which the present invention is applied.

FIG. 1 is a schematic diagram illustrating a device for recording information pattern patterns on recording paper 12. As shown in FIG. The recording paper 12 is
ffll, from the supply roller 13 to the take-up roller 1
It is shown to move up to 4. However, the relative movement between the device 11 and the recording paper 12 is
It is clear that either or both of these can be done in any suitable manner that makes them practical.

The device 11 includes a suitable reservoir 16 for storing the particular ink to be used. This ink reservoir 16 passes through a communication pipe 17 to a device J111 for ejecting ink droplets;
It communicates with a print head (ink jet head) 18 . Electronic pulse generator 19 sends pulse voltages to the printhead through suitable transmission means 21, such as a wire.

At this time, when the print head 18 receives one pulse voltage from the +itr generator 19, it ejects one discrete droplet 22 of ink through the orifice 24. That is, each pulse voltage produces a single ink droplet, the volume of which is controlled by the energy of the applied pulse voltage.

In the embodiment shown in FIG. vS1, groups of ink droplets ejected as the recording paper 12 passes the print head 18 form #X23 on the recording paper.

In order to form a record of an accurate pattern of information on the recording paper, the ink droplets must travel in a substantially straight trajectory from the orifice 24 of the printhead 18 to the recording paper 12.

Also, by precisely positioning the device 11 and the recording paper 12 relative to each other, the ink droplets can be impinged to form a predetermined information pattern based on pulse signals from the electronic pulse generator 19. . Additionally, the ink droplets must be of precise shape and volume for optimal recording of the information pattern. That is, this means that the ink droplets are uniform in size from droplet to droplet and are ejected at the intervals of the electrons 45 from the pulse generator 19.

FIGS. 2 and 3 are top and cross-sectional views of a preferred droplet ejector, a detailed addendum to the print head 18. FIG.

However, in the cross-sectional view of FIG. 3, for convenience of structural explanation, the printed head 18 is shown in a state in which the power is not turned on (a state in which no electricity is applied to the pressure plate 41, which will be described later). . Print head 18 consists of a housing 36 forming part of a pressure chamber 37. The communication pipe 17 conveys ink from the ink reservoir 16 to the entry passage 38 of the pressure chamber.

Pressure chamber 37 includes an outlet passage 39 . The upper wall of the pressure chamber 37 is formed by a pressure plate (flexible plate) 41. Pressure plate 41 is preferably made of piezoelectric material. In the illustrated embodiment, pressure plate 41
is two piezoelectric plates 42°4 that expand laterally.
3, each of which forms a Tg plate-like disk, and these are mutually fixed by a conductive thin film 44.

conductive waves [46, 47
is attached (l), which is electrically connected to the faces of both plates and is led to the outside by wires 48, 49. Therefore, by applying a voltage to the two surfaces, it is possible to apply a voltage to the (play) 42,4]. In this case, when a suitable positive voltage is applied to 42.43, one plate 42 contracts and the other plate 43 expands, causing the pressure plate 41 as shown in FIGS. When an appropriate negative voltage is applied to 42 and 43, the former plate 42 expands and the latter plate 43 contracts, causing the second plate to As shown in FIGS. 5 and 8, the pressure plate 41 is bent outward from the pressure chamber 37.

In this way, the pressure plate 41 is composed of two piezoelectric plates)
42.43 are joined to form an integral structure (
Compared to a pressure plate with only one electric plate (hereinafter referred to as unimorph), it deforms about twice as much in response to a given pulse, so the volume change efficiency of the pressure chamber 37 is is high.

Bimorphs can be achieved with a smaller pulse voltage peak value than unimorphs. The above bimorph,
In either case, if the unimorph is formed into a disk shape, the deformation efficiency with respect to the applied voltage is good, so it is also effective in deforming the volume of the pressure chamber 37.

However, when the pressure plate 41 is deflected inward into the pressure chamber 37 due to the application of a positive voltage, the volume of the pressure chamber is reduced, pressure is applied to the ink within the pressure chamber, and a portion of the ink is pushed out toward the outlet passage 39. Jetting toward the recording paper 12, while communicating the remaining ink against the hydrostatic pressure of the ink reservoir? ! '17 to return to the ink reservoir 16.

The end of the outlet passageway 39 has a 1fi tight diameter orifice 52.
, thereby precisely controlling the diameter of the ink droplet ejected from the print head 18.

The size of the ink droplet is a function of the voltage across plates 42 and 43 and its pulse width as well as the diameter of orifice 52.

Pressure plate 41 is seated within printhead housing 36, as shown in FIG. 3, by suitable access means such as epoxy adhesive. A suitable piezoelectric transducer for the pressure plate 41 is manufactured by Flevite, Ohio, USA.
It is commercially available under the trade name "Bimorph" by Tuboration I).

Now, electricity 1 (not shown) is applied to the print head 18,
When the pressure pulse is not sent yet, as shown in FIG. 4(^), a negative voltage is applied to the pressure plate 41 by the pulse generator 619, so that the pressure plate 41 is activated as shown in FIG. 5 prior to the printing operation. It is held in an outwardly bent position as shown in the figure. In this case, the ink will create a slight meniscus extending from the orifice 52. This meniscus is caused by static pressure from the ink reservoir 16 being applied to the ink in the pressure chamber 37. The surface tension of the ink prevents the ink from dripping out of the orifice.

However, during printing, when the pressure plate 41 is in this state, a positive pulse voltage from the pulse generator 19 is applied to eject ink droplets. That is, when an electrical pulse signal having a selected amplitude and pulse width from the pulse generator 19 is applied to the pressure plate 41 via the conductor +1!48.49, the pressure plate 41
5 suddenly changes from the state shown in FIG. 5 to the state shown in FIG.
Apply a sudden pressure pulse to the ink inside. The pressure pulse causes the ink within the pressure chamber to travel through the outlet passageway 39 to the orifice 52 and exit the orifice 52 as discrete droplets in response to the pulse, as shown in the schematic diagram of FIG.
is sprayed from. This small 1F 122 collides with the recording paper 12, and the relative movement of the print head and the opening of the recording paper will constitute a line or other shape depending on the direction and magnitude of the relative movement.

As described above, before injection, a negative voltage is applied to the pressure plate 41, which forms an upwardly convex shape, and when a positive voltage is applied during injection, the pressure plate 41 deforms into a concave shape upwardly. Therefore, the amount of volume change is approximately twice that of the case where a positive or negative voltage is applied from the no-load voltage, and the volume change efficiency of the pressure chamber (7) is large. It is possible to make the voltage value smaller and change the same value L by 4. After injection, a negative voltage is applied to the pressure plate 41 again to restore the upwardly convex shape, and the next signal wait.

The size of the inlet and outlet passages 38, 39 is limited by the viscosity of the ink used. Larger tubes may be necessary for more viscous inks. When the pressure pulse by the pressure plate 41 ejects the ink droplet 22 from the orifice 52, that pressure also acts to force the ink to flow back through the inlet passageway 38 and into the ink sump against the hydrostatic pressure of the ink applied from the ink sump 16. . In this case, the amount of backflow is limited by adjusting the length and diameter of the inlet passageway 38, and the anti-friction forces of the ink limit the amount of backflow that occurs during ejection of ink droplets.

It has been found that when a layered liquid flows through a tube of length L at a speed of ■, the external friction inhibiting force F is expressed by the following equation.

F=8πηLV However, η is the viscosity coefficient of the liquid.

The hydrostatic pressure exerted on the ink reservoir 16 thus acts to cause the droplets to exit the orifice 52 rather than forcing the ink within the pressure chamber back into the inlet passageway 38. Two inches of hydrostatic pressure is sufficient for most purposes.

If backflow through the inlet L1 passageway 38 is not restricted, the pressure pulse from the pressure plate 41 will cause a large amount of ink to flow through the inlet passageway 38.
Most of the energy is expended in pushing the ink droplet 22 in the opposite direction through the orifice 8 and is not able to build up the pressure in the pressure chamber sufficiently to eject the ink droplet 22 from the orifice 52.

Additionally, the length and diameter of the passageway 39 must be selected to result in lower frictional losses compared to those caused by the hydrostatic pressure and the inlet passageway 38 and the communicating tube 17.

The allowable hydrostatic pressure applied through the ink reservoir 16 is Represented by

where D is the diameter of the orifice S is the constant of the surface tension of the ink. However, in order to stabilize the 7 varnish at the orifice 52, the ink must not wet the curved surface of the housing 36 of the printhead 18. That is, the natural contact angle between the ink and the front surface of the housing 36 needs to be 90' or more. This condition can be satisfied by using water-based ink and coating the front surface 57 of the housing 36 with Tear-On (trade name of DuPont, USA). Although it is preferred to coat surface 57 with Teflon, there are many other ink and solid combinations with contact angles greater than 90'' that are suitable for the purposes of this invention.

Figure 4 (^) and (B) show the pressure plate 41 as a function of time opening.
FIG. 3 is a diagram schematically showing the correlation between the input voltage to the pressure chamber 37 and the pressure at which the liquid in the pressure chamber 37 leaks.

The injection system remains in the state of FIG. 5 until just before a positive input voltage pulse 62 is applied to pressure plate 41 at time t1, but the positive voltage applied at tl
is deflected to the condition shown in FIG. 6, thereby increasing the pressure on the ink to about 10 times the value in the condition shown in FIG. The maximum value of the pressure applied to the ink (point 64) is
1 = 20 psi (bonds per square inch). Particularly preferred is around 5 psi.

In this case, because of the reaction time of the pressure plate 4 and the inertia of the ink, the pressure of the ink does not rise immediately even if the voltage pulse is applied rapidly at time t1.

That is, as shown in FIG. 4, the ink pressure, which was maintained at a predetermined static value at time tl*, rises to the maximum value at time t2, at 64th place 16 of l'. The increasing high pressure at this point 64 acts as a driving force on the ink at the orifice 52, so that the column of ink in the outlet 1'' passageway 39 flows out of the orifice 52 and reaches a high velocity. This high velocity overcomes the surface tension of the ink in the orifice 52 and causes the column of ink to protrude from the orifice 52.

Therefore, C-Predetermined time opening-1, that is, from t2 to L in FIG.
3, when the voltage across the pulse generator 19 is switched back to the negative initial voltage, the pressure within the pressure chamber 37 rapidly increases to the value indicated by α66 at time [, and finally returns to the nailed state 67 at time L5.

At this time, the especially protruding ink column becomes a droplet 22 and separates from the orifice 52 due to the above-mentioned relationship between the ejection speed and this pressure reduction effect, and takes a substantially natural linear trajectory to the recording paper. It flies, reaches the recording paper, and creates a small dot within the line 28. This process is described in detail in the series of Figures 5-8.

FIG. 5 shows the previous state at time t, that is, when the power is turned on,
A negative voltage is applied to the pressure plate 41 from the pulse generator 19 .

FIG. 3 is a cross-sectional view of the print head in a state where pressure is applied.

In this state, when a positive voltage pulse for printing is applied from the pulse generator 19, the pressure plate 41, which had been bent upward, passes through a flat state and bends inward, shifting to the state shown in FIG.

FIG. 6 shows the state of the pressure chamber when only the inward deflection of the pressure plate 41 is at its maximum, that is, at time t3. In this case, applying a positive voltage to the pressure plate 41 causes one plate 42 to contract and the other plate 43 to expand, thereby deflecting the pressure plate 41 inward and reducing the volume of the pressure chamber 37. It acts to move a certain amount of ink.

At this time, depending on the city water pressure in the ink reservoir 16 applied to the inlet passage 38, the viscosity of the ink, the length of the inlet passage 38, the diameter of the inlet passage, and the matters mentioned above! 1. A portion of the displaced ink flows back into the communication tube through the inlet passage 38.

However, the movement of ink within the pressure chamber 37 caused by the pressure plate 41 mainly serves to push the ink column 101 out of the orifice 52.

FIG. 7 shows the situation after the voltage supply has been reduced at 14, indicated by point 66 in FIG. 5, although the pressure plate 41 is still maximally deflected.

In other words, this shows a state in which the voltage application to the pressure plate 41, which had been deflected inward to the maximum extent, is reversed and the pressure plate 41 begins to return to the state shown in FIG. 5. In this case, pressure chamber 3
The ink pressure in column 7 decreases to the maximum at point J shown in FIG. 4 (11), while the acceleration of ink column 101 changes to deceleration.

However, since a portion (the leading end) of the ink column 101 has already reached the ejecting speed, it decelerates and separates from the other ink column to form an ink droplet 102. The remainder of the ink column is then still in communication with the ink in the pressure chamber 37.

The fjSa diagram shows the state of the injection system at time t5 in the fPS4 diagram. That is, the pressure plate 41 is as shown in FIG.
), the position shown at point 67 has returned to its preparatory position at point 67 (before the positive voltage pulse was applied);

In this case, the decrease in ink pressure from point 66 to point 67 shown in FIG. 4(B) acts to suck the remainder of ink column 101 into outlet passage 39.

During this time, the surface tension of the ink droplet 102 ejected from the oriice acts to make the droplet spherical in shape. After each pulse creates a droplet, the ejection system returns to equilibrium as shown in FIG.

Note that the amount of ink to be ejected depends on the width and voltage value of the output pulse from time L1 to t3, that is, the applied energy. Ink droplets can be created that have a diameter. The next pulse 68 thus applied will eject another droplet. Therefore, the frequency of droplets is controlled by the frequency of the voltage pulses outside when the pulses are applied.

Examples of specific parameters when using the apparatus described in Figures 1-3 for rapid ejection of high quality ink droplets are:
It is as follows.

Table 1 FIG. 9 is a schematic diagram of the same apparatus as shown in FIG. 1, except that patterns such as letters and numbers are printed by a dot arrangement of ink.

It has a series of printing rads 111-120 which can be individually controlled by an electronic pulse generator 19.

Print heads 111-120 are grouped vertically in stack 110 so that they can fire 1-10 ink petals at the same time. With this invention, the character “′
Suppose you want to print the character "]. Figure 11 shows the character "]
6 shows a method for constructing rows and columns of ink dots having 9 positions on the X-axis and 10 positions on the Y-axis. The letter “T” first stacks 1 at position 1 of the X glaze.
By determining the position of 10, the following is formed by the apparatus shown in FIG. That is, the topmost print head 111 is driven so that an ink dot is written at position 10 on the Y axis.

The stack 110 is then moved to position 2 on the X-axis and the print head 111 is again driven to mark another ink dot at position 10 on the Y-axis. This process continues until the stack 110 is located at position 5 on the X-axis, at which point 10
All of the printing rads are driven so that ink droplets are ejected from each of the printing rads 111-120. This marks droplets at positions 1 to 10 on the Y axis to create the vertical element of the letter "T". Thereafter, as the stand tank 110 moves from position 6 to position 9 on the X-axis, the printing pad 111 is driven to print a dot at position 10 on the Y-axis, respectively.

Although FIG. 9 shows ten printing rads from 111 to 120, it is known that legible characters can be created by at least five vertical positions. However, it is preferred that the print head have 7-10 vertical positions to produce characters with a legible configuration.

Stack 110 is attached to a threaded support 121 that cooperates with a lead screw 122. The main screw is its end j23
, 124, and is driven by a step motor 126. The number of threads per inch on the lead screw 122 is selected to move the print head horizontally between two adjacent rows on the X-axis of FIG. ing. By this method, step motor 126
Each unit rotation advances the print head from the previous position (6 to the next position) along the X-axis in FIG. 1.1.

FIG. 10 shows an apparatus 6 having a plurality of print heads 131-140 in side-by-side, not stacked, relationship as shown in FIG. Recording paper 12 moves perpendicularly to the head to print characters and other shapes. It will be appreciated that the series of printheads may be oriented either vertically or horizontally as desired.

Each nozzle in the stack may thus be supplied with ink, for example from a vertically arranged piezoelectric plate. Similarly, the relative movement between the paper and the head can be either vertical or horizontal.

As described above, the present invention 1:2J: produces an excellent effect that satisfies all the basic conditions r1 required for the above-mentioned ink jet recording system.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a recording device incorporating a droplet jet recording device equipped with a print head according to the present invention; FIG. 2 is a plan view of an embodiment of the droplet jet recording device shown in FIG. 1; FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 2, FIG. 4A is a diagram showing voltage pulses applied to the droplet ejector, and FIG. Figure 5 is a cross-sectional view of the liquid injection device showing the state just before a voltage pulse is applied to the piezoelectric plate; Figure 6 is a diagram showing the variation of the liquid pressure in the pressure chamber as a function; 7 is a sectional view of the device 6 in a state where the piezoelectric plate is about to return to its original position; FIG. 8 is a sectional view of the device 6 with the piezoelectric plate in its original position 10 is a cross-sectional view of the device in the state when it is restored to the state shown in FIG. FIG. 11 shows characters formed by the recording device shown diagrammatically in FIGS. 9 and 10. 11...Recording device 12...Recording medium (recording paper) 16...Ink fJli 18...
... Print head 19 ... Electronic pulse generator 22 ... Ink small 2i 24 ... Orifice 37 ... Pressure chamber 38 ... Population Passage 39... Outlet passage 41... Pressure plate (flexible plate) 42.43... Piezoelectric plate 52... Orifice 56...・Meniscus agent Patent attorney No 1) Parent-in-law Figure 4 Figure 5

Claims (3)

[Claims] (1) A print head of an ink jet recording device that ejects ink droplets by deforming the internal volume of a pressure chamber by an electromechanical conversion means provided corresponding to a pressure chamber filled with ink, and wherein the electric machine An ink jet recording device characterized in that the converting means has a circular plate shape. (2) The ink jet recording apparatus according to item fjSi of the claims, characterized in that the electromechanical conversion means comprises a piezoelectric conversion element. (3) The ink ejection according to claim 1 or 2, wherein the electromechanical conversion means has an integral structure by joining two piezoelectric conversion elements. Recording device.