JP3362732B2 - Inkjet head driving method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording by flying ink droplets.
Ink-jet method for forming ink images on media such as paper
More specifically, on-demand
The present invention relates to a jet head and a driving method thereof. 2. Description of the Related Art A conventional ink jet head has one
It has one ink pressurizing chamber for the nozzle,
The ink is ejected by pressurizing the pressure chamber. I
In today's demand for higher recording speed, the head configuration
In this case, there is a limit to the ink ejection repetition frequency. So
Here, two pressure chambers and pressure means are provided for one nozzle.
JP-A-2-162048, which enables high-speed response,
JP-A-3-43253, JP-A-2-303845
It has been disclosed. Specifically, (Conventional Example 1) Japanese Patent Application Laid-Open No.
First pressure chamber 2 which communicates pressure chambers 200
01 and a second pressure chamber 202. These two
Delay the piezoelectric elements 203 and 204 in the pressure chambers 201 and 202
Drive by giving time to increase the ink supply capacity
Higher meniscus receding and higher frequency
It enables the ejection of droplets. (Conventional example 2) JP-A-3-43253 discloses that
As shown in FIG.
Two pressure chambers 206, 207 that can be pressurized individually
Having. Pressurize these two pressure chambers with a time difference
By doing so, driving at low voltage is possible and
This is to increase the limit repetition frequency of ink droplet ejection. (Conventional example 3) JP-A-2-303845
Is the first for pressurizing the pressure chamber 208 as shown in FIG.
Without passing through the first energy generating means 209 and the pressure chamber 208
A sub flow path 211 communicating with the nozzle 210;
Energy generating means 21 for pressurizing the inside of
Two. Therefore, the meniscus after ink droplet ejection
Quickly returns to its initial position, with high frequency characteristics and high speed
It enables recording. [0005] The above prior art inks
Each jet head is connected to one nozzle.
And having two pressure generating means,
Discloses a configuration that focuses only on ejecting ink droplets
Have been. On the other hand, such an ink jet head
Changes the ink pressurized in the pressure chamber from the nozzle
Nozzle on the recording paper.
Increase in ink viscosity due to evaporation of solvent from
Solidification, adhesion of dust, and air bubbles
Discharge frequency drop, nozzle opening clogging,
Ink droplets may bend and fly, resulting in poor printing.
There was a problem. That is, the ink described in the above prior art
Realizes high-frequency ink droplet ejection like a jet head
In order to perform printing, the menis
It is necessary to take measures to prevent thickening of ink that forms scum.
You. The present invention has been made in view of such circumstances.
The purpose of which is to use two pressure chambers
Eject ink droplets at high frequency
Ink jet that can maintain the characteristics
To provide heads. [0009] The ink jet of the present invention.
In the head driving method, the ink in the ink tank is supplied.
A first pressure chamber and a second pressure chamber communicating with the first pressure chamber
And a nozzle communicating with the second pressure chamber.
A plurality of second pressure chambers are commonly connected to the power chamber,
The first pressure chamber has first pressure generating means, and the second pressure chamber has
Denotes an ink jet head having a second pressure generating means
Driving method for ejecting ink droplets from the nozzles.
In the imaging, the first and second pressure generating means are used simultaneously.
To eject ink droplets from the nozzles
Outside, the nozzle is driven by driving only the first pressure generating means.
Vibrating enough not to discharge the meniscus in the
Features. FIG. 1 shows an ink jet head according to the present invention.
It is a perspective view of one Example. This inkjet head
Has a plurality of nozzles 2 (five in FIG. 1). Figure
The head 1 has an etching technique and a stack of multiple thin plates.
And the ink flow path by plastic injection molding.
The base 1 provided with the uneven surface and the pressure plate 3 are laminated and joined.
Thus, an ink flow path is formed. Of pressure plate 3
Common electrode 4 is plated or sputtered on one side
Is formed. On the upper surface of the common electrode 4, one
A pair of a first piezoelectric element (hereinafter referred to as PZT) 6 and each nozzle
The corresponding plurality of second PZTs 5 have electrical conductivity.
Adhered to. Of the first PZT6 and the second PZT5
Electrodes are provided on both sides, and signal lines (not shown)
And a drive circuit (not shown). First pressure generation
The means is constituted by the first PZT 6 and the pressure plate 3.
The second pressure generating means is composed of the second PZT 5 and the pressure plate 3.
It is composed of Ink not shown is ink
The ink tank is supplied from the tank via the tube 7
And the inside of the ink flow path from the nozzle 2 to the nozzle 2. FIG. 2 is a plan view of the ink jet head of FIG.
FIG. 3 is a sectional view taken along the line AA ′ of FIG. Figure 2 below
The ink flow path structure will be described with reference to FIG. 9 is a first pressure common to all nozzles.
A first PZ at a position corresponding to the first pressure chamber 9.
T6 is provided. The first pressure chamber 9 has a partition 10
A plurality of second pressure chambers 8 separated by
You. The second PZT 5 is located at a position corresponding to the second pressure chamber 8.
Each is arranged. The nozzle 2 has a second pressure chamber 8
The taper is formed so that the cross-sectional shape becomes narrower.
You. Reference numeral 14 denotes a supply port, which is a first pressure chamber 9 and a second pressure chamber.
In the direction of the ink tank generated by the volume change of the force chamber 8.
It plays a role in controlling the flow of ink. 11 is a pipe
And is joined to the tube 7. Inside the pipe 11
Has an introduction passage 12 formed therein, and the
Played a role in guiding ink inside the inkjet head
You. Here, the ink from the ink tank to the introduction path 12
Acoustic impedance of the flow path, that is, flow path resistance and inertia
Make sure that the closet does not affect the ink drop ejection characteristics.
It is set as small as possible. Further, the pressure plate 3 and the first P
ZT6 and the second PZT5 have large deformation amplitude and
Combinations that increase synthetic compliance
Selected and adopted. In this embodiment, the pressure generating means
Although PZT was used, a voice coil was used as another embodiment.
It is also possible to use the expansion movement of bubbles or bubbles. FIG. 4 shows an ink jet head of the present invention.
FIG. 5 is a driving waveform diagram for explaining the driving method according to the first embodiment.
FIGS. 6A to 6C are views for explaining an ejection operation, and FIGS.
(C) is a diagram for explaining a non-ejection operation. In FIG. 4, V1 marks the first PZT6.
V2 is applied to the second PZT5.
FIG. Furthermore, from time t1
The interval t4 is a drive waveform when an ink droplet is ejected,
From time t5 to time t8, the drive used in the case of non-ejection
It is a waveform. Hereinafter, the ejection and non-ejection operations of the first embodiment will be described.
I will tell. (Ejection Operation in First Embodiment) Before t1
In the initial state of the first PZT6 and the second PZT5,
Pressures 15 and 16 are applied, respectively. At this time, the first
PZT6 and second PZT5 are deformed to a reduced state.
You. For this reason, the pressure plate 3 causes the first
Radius in the direction to reduce the volume of the pressure chamber 9 and the second pressure chamber 8
Deformed and stationary. However, from time t1 shown in FIG.
In the process of the interval t2, the first and second PZTs are gradually marked.
Because the applied voltage decreases, the first PZT 6
Direction, and the second PZT 5 deforms in the direction of arrow 21.
You. That is, the first pressure chamber 9 and the second pressure chamber 8 are enlarged.
Deform. Due to this deformation, the first pressure chamber 9 and the second pressure chamber
A flow occurs in the ink inside the power chamber 8. Supply port 14
In the first pressure chamber 9 in the directions of arrows 26 and 25.
Flows in the nozzle 2 and the second pressure chamber 8 by the arrow 2
Ink flows in the 3, 24 directions are generated. Especially nozzle 2
In the above, the meniscus 36 which is greatly drawn in is formed
Is done. From time t2 to time t3 shown in FIG.
In the process, the voltage applied to the first PZT 6 and the second PZT 5
The pressure is zero and the movement of the PZT stops. But supply
The inside of the port 14, the first pressure chamber 9, and the second pressure chamber 8
Flow occurs in the direction of arrows 27 to 30 due to inertia.
You. By this flow, the meniscus in the nozzle 2 becomes 37
To shrink like Flow in the direction of arrows 27-30 occurs
The reason is that the meniscus from time t1 to time t2
As a result, the arrow 23 at time t2
The kinetic energy of the ink in 24 directions is indicated by arrows 25 and 26
Is smaller than the kinetic energy of the ink
is there. The process from time t3 to t4 shown in FIG.
Then, the voltage is again applied to the first PZT6 and the second PZT5.
Addition is started. Accordingly, the first PZT6 and the second PZT6
ZT5 starts radial deformation in the directions of arrows 32 and 31
You. That is, the first pressure chamber 9 and the second pressure chamber 8 are reduced.
Deform. As a result, the first pressure chamber 9 and the second pressure chamber 8
Inside, the flow in the directions of arrows 27 to 30 due to the inertia
Flows in the directions of the added arrows 33, 34 and 35 occur
I do. In particular, the flow of arrow 33 is high speed, so the ink is nozzle
Is pushed out into an ink pillar 38 from the
Fly as drops. Also, an arrow 35 toward the supply port 14
Is sufficiently smaller than the flow of arrow 33.
You. (Non-ejection operation in the first embodiment) t5 or later
In the previous state, as in the initial state of the discharge operation, the first pressure chamber
9 and the second pressure chamber 8 are provided with the first PZT 6 and the second PZT.
It is deformed radially in the direction to reduce the volume by T5 and it is stationary
You. From time t5 to time t6 shown in FIG.
In the process, the voltage applied to the first PZT6 gradually decreases
The first PZT 6 is deformed in the direction of arrow 39,
The volume of the first pressure chamber 9 is increased. However, the second PZ
At T5, there is no change in applied voltage, so a volume change occurs.
Absent. Only the volume of the first pressure chamber 9 expands and deforms.
The ink inside the first pressure chamber 9 and the second pressure chamber 8 is
Are smaller arrows than the flow of arrows 23 to 26 in FIG.
A flow in the directions of the marks 40 and 41 occurs. In addition, nozzle 2
The meniscus is pulled in as at 46. From time t6 to time t7 shown in FIG.
In the process, the voltage applied to the first PZT 6 becomes zero,
The movement of the first PZT 6 stops. However, supply port 14
Ink inside the first pressure chamber 9 and the second pressure chamber 8
A flow occurs in the direction of arrow 42 due to the nature. This arrow 42
The flow in the direction is also the flow in the directions of arrows 27 to 30 in FIG.
It is a small flow. Nozzle due to flow in the direction of arrow 42
The meniscus of the rule 2 returns to the original position 47. The time t8 to the time t8 shown in FIG.
In the process, the application of the voltage to the first PZT 6 is started again.
You. Accordingly, the first PZT 6 is bent in the direction of arrow 43.
Deformation starts, and the volume of the first pressure chamber is reduced and deformed. So
As a result, the flow in the direction of the arrow 44 flows inside the second pressure chamber 8.
Occurs. Also, the inside of the first pressure chamber 9 and the supply path 14
Generates a flow of ink in the direction of arrow 45. But,
Since the ink flow speed in the direction of arrow 44 is low,
The ink protrudes from the nozzle 2 to the extent indicated by 48, but the ink surface
Do not fly as ink droplets overcoming surface tension
In addition, the meniscus surface is slightly vibrated. As described above, the first PZT 6
Regardless of whether or not ink is ejected, drive
A periodic drive waveform such as the dynamic waveform V1 is applied to the inside of the nozzle.
Vibrates the meniscus slightly. This minute vibration
The effect of stirring the ink on the surface of the meniscus formed inside
Have fruit. The second PZT 5 ejects ink droplets.
Only when it is desired to output
It is configured to perform driving. FIG. 4 shows the driving waveforms V1 and V2
Changes start at the same time during the periods t1, t2, t3, and t4.
, But does not have to match exactly
There is no. Furthermore, a trapezoidal wave is adopted as the drive waveform
Are square waves, sine waves, exponential waves, and combinations of these waveforms.
It is also possible to use a combined waveform. FIG. 7 shows an ink-jet method according to the first driving method.
Meniscus displacement (volume) when the head is driven
6 is a graph showing a time change of the data. Here, W1 is ejection
During operation, W2 represents the time change of the meniscus during non-ejection operation.
Represents. The times t1, t2, t3, and t4 in FIG.
4, time t1, t2, t3, t4 or t5, t
6, t7, and t8, respectively. The above-mentioned theory of operation
Although it overlaps with the description, W1 will be described first. From the time t1 to the time t2, the meniscus
Is drawn. The maximum pull-in amount 50 of the meniscus is
The maximum volume of the meniscus 36 is shown. From time t2
The meniscus 37 continues to shrink over time t3. Reduction
The speed is gradually decreasing because of the flow resistance
Is attenuated. From time t3 to time t4
Thus, an ink column is formed. At time t4, the menis
There is a discontinuous point of the scum displacement amount. This is because the ink pillar
Flying away from nozzle 2 as an ink drop
Is represented. 49 indicates the volume of the ink droplet. Time
After the time t4, the meniscus returns to its original position while slightly vibrating.
Settle. The ink jet head of the present embodiment has a time t
Short time from 4 to stabilization, good frequency response
You. Next, W2 will be described. From time t1
At time t2, the meniscus is retracted. Time t2
From time t3, the movement of the first pressure plate 6 stops.
But the direction of meniscus contraction due to the inertia of the ink
Causes a flow of ink. However, the contraction of this meniscus
The small speed is smaller than the meniscus reduction speed shown in W1.
No. The reason is that the meniscus 46 is pulled at the time t2.
The drawing amount is smaller than the drawing amount of the meniscus 36.
Therefore, the reduction amount of the inertance in the nozzle 2 is W2
Is small. That is, the flow in the direction of arrow 41
Kinetic energy and flow kinetic energy in the direction of arrow 40
Because the difference in energy is small, the flow of the arrow 42 becomes small.
Because it was. Therefore, at time t3, the meniscus is completely
I can't return to From time t3 to time t4, the menu
Although the scass is pushed out of the nozzle 2, the ink surface
When the ink is not ejected as ink droplets due to the surface tension
After the time t4, the vibration gradually attenuates and stabilizes. FIG. 8 shows an ink jet head of the present invention.
FIG. 9 is a driving waveform diagram for explaining the driving method according to the second embodiment.
FIGS. 10A to 10C are diagrams for explaining an ejection operation, and FIG.
FIGS. 11A to 11C illustrate one of the non-ejection operations.
(A)-(c) is a figure explaining another non-ejection operation | movement. In FIG. 8, V3 corresponds to the first PZT6.
It is a drive waveform applied. Waveform V4 indicates that during ejection operation
It is a drive waveform applied to the second PZT5. Waveform V5
Is the drive wave applied to the second PZT 5 during the non-ejection operation
And the waveform V6 indicates the second PZ during another non-ejection operation.
It is a drive waveform applied to T5. Hereinafter, the discharge of the second embodiment
The ejection and non-ejection operations will be described. (Ejection Operation in Second Embodiment) Before t1
In the initial state, the voltage 52 is applied to the first PZT 6.
ing. At this time, the first PZT 6 is transformed into a reduced state.
I have. Therefore, the pressure plate 3 is moved by the action of the bending stress.
1 deforms radially in the direction to reduce the volume of the pressure chamber 9 and stops.
ing. However, from time t1 shown in FIG.
In the process of the interval t2, the voltage applied to the first PZT 6 gradually increases.
Decreases, the first PZT 6 moves in the direction of arrow 55
Deform. That is, the first pressure chamber 9 expands and deforms. I
However, the second PZT5 has no change in applied voltage.
No deformation occurs. Due to the volume change of the first pressure chamber 9,
The ink inside the first pressure chamber 9 and the second pressure chamber 8 includes:
A flow in the direction of arrows 56 to 59 occurs. At the same time
The meniscus 69 is drawn inside the chisel 2. From time t2 to time t3 shown in FIG.
In the process, the voltage applied to the first PZT 6 becomes zero,
The movement of the first PZT 6 stops. However, supply port 14
Ink inside the first pressure chamber 9 and the second pressure chamber 8
The flow in the direction of arrows 60-63 occurs due to the nature. This style
As a result, the meniscus in the nozzle 2 is reduced as shown by 70.
Make it small. From time t3 to time t4 shown in FIG.
In the process, a voltage is applied to the first PZT6 and the second PZT5.
Addition is started. Accordingly, the first PZT6 and the second PZT6
ZT5 starts radial deformation in the directions of arrows 65 and 64,
The volumes of the first pressure chamber 9 and the second pressure chamber 8 are reduced and deformed.
As a result, inside the first pressure chamber 9 and the second pressure chamber 8,
Add to the flow in the directions of arrows 60 to 63 due to the inertia
Flows in the directions of the arrows 66, 67, and 68 are generated.
In particular, since the flow of arrow 66 is high speed, ink flows from the nozzle.
It is pushed out as an ink column 71, and eventually becomes an ink drop.
I will fly. Also, the flow of the arrow 68 toward the supply port 14
This is sufficiently smaller than the flow of the arrow 66. (Non-ejection operation in the second embodiment)
Using the waveforms V3 and V5, the non-ejection operation process of the second embodiment will be described.
explain. The drive waveform from time t1 to time t3 is a discharge
The flow of the ink is the same as that at the time of the operation, and the flow of the ink is as shown in FIGS.
It is the same as that shown in FIG. Again, FIG. 10 (a),
This is shown in (b). From time t3 to time t4 shown in FIG.
In the process, the application of the voltage to the first PZT 6 is started.
You. Accordingly, the first PZT 6 moves in the direction of arrow 74
Only the deformation is started, and the volume of the first pressure chamber is reduced and deformed.
However, since no voltage is applied to the second PZT5,
The volume of the pressure chamber 2 does not change. As a result, the first pressure
Arrows generated by inertia in the chamber 9 and the second pressure chamber 8
The direction of the arrow 72 added to the flow in the direction of 60 to 63
Flow occurs. The ink is as shown in nozzles 2 to 73
Protrudes but overcomes the surface tension of the ink and
Does not fly, and the meniscus surface is slightly vibrated.
Let This minute vibration is caused by the meniscus formed in the nozzle.
It has the effect of stirring the ink on the surface. As described above, the first PZT 6
Regardless of whether or not ink is ejected, drive
A periodic drive waveform such as the dynamic waveform V1 is applied to the inside of the nozzle.
Is made to vibrate the meniscus minutely. (Another Non-ejection Operation in Second Embodiment) FIG.
8 describes another non-ejection operation process using waveforms V3 and V6.
I do. In the initial state before t1, the first PZT6
Is applied with the voltage 52, and the voltage is applied to the second PZT5.
The volume of the first pressure chamber is reduced,
The volume of the pressure chamber 2 is deformed to an expanded state and is stationary. From time t1 to time t2 shown in FIG.
In the process, the electric power gradually applied to the first PZT 6 is gradually increased.
Pressure decreases, and conversely, voltage is applied to the second PZT5
Is done. Therefore, the first pressure chamber 9 is expanded from the contracted state.
The second pressure chamber 8 undergoes large deformation and contracts from the expanded state.
You. Therefore, the flow of the generated ink is the first pressure chamber.
9 only flows in the directions of arrows 77 and 78.
You. However, in all of the plurality of nozzles 2, ink droplets
Arrow is not required to discharge
No flow in the direction of 77,78 occurs. From time t2 to time t3 shown in FIG.
In the process, the first PZT6 is in a state where the applied voltage is zero.
And the second PZT 5 stops at the applied voltage of 54.
ing. At this time, the flow in the directions of arrows 79 and 80 becomes inertial.
More likely to occur. Therefore, the meniscus 87 is
Project outside. However, the ink flow speed is low.
Therefore, the meniscus 87 should not fly as ink droplets.
Agitates ink near the meniscus by micro-vibration
Let it. From time t3 to time t4 shown in FIG.
In the process, the voltage applied to the first PZT6 gradually increases
On the contrary, the applied voltage of the second PZT 5 decreases.
You. Therefore, the first PZT 6 changes in the direction of arrow 82.
The first pressure chamber 9 is reduced and deformed. Also, the second P
ZT 5 is displaced in the direction of arrow 81 to expand second pressure chamber 8.
Large deformation. As a result, the directions of the arrows 83, 84, 85
Flow of ink occurs, each flow and the first pressure
The meniscus 8 is formed by the volume change of the chamber 9 and the second pressure chamber 8.
8 hardly vibrates. As described above, the first PZT 6
Regardless of whether or not ink is ejected, drive
A periodic voltage like the moving waveform V3 is applied. Ink drop
When driving is performed, the driving waveform V3 is applied to the second PZT5.
Drive with drive waveform V4 according to timing
It has become. If ink drops are not ejected
In this case, the driving waveform V5 or V6 is used for driving the second PZT5.
Use It should be noted that a trapezoidal wave is employed as the driving waveform.
However, square waves, sine waves, exponential waves,
It is also possible to use a combination of waveforms. FIG. 12 shows an ink according to an embodiment of the present invention.
Meniscus when using the jet head drive method
5 is a graph showing a change over time of a displacement amount (volume) of the first embodiment. This
Here, W3 is an ejection operation when the drive waveforms V3 and V4 are used.
Is the case. W4 is the value when drive waveforms V3 and V5 are used.
In the case of the non-ejection operation, W5 represents the drive waveforms V3 and V6.
This is a case of a non-ejection operation when used. Time t in FIG.
1, t2, t3, t4, t9, t10 in FIG.
Times t1, t2, t3, t4, t9, and t10, respectively
Yes, it is. Although the description is the same as that of the above-described operation, first, W3
Will be described. From time t1 to time t2,
The varnish 69 is drawn in. Maximum pull of meniscus 69
The injection amount 90 indicates the maximum volume of the meniscus 69.
You. The meniscus 70 contracts from time t2 to time t3.
Keep small. The reduction speed is gradually decreasing in the channel
This is because the resistance is acting. From time t3 to time t4
, An ink column is formed. At time t4
Ink drops leave nozzle 2 and start flying as ink drops
I do. Reference numeral 89 denotes the volume of the ink droplet in this case.
You. After time t4, the meniscus slightly vibrates and returns to the original
Settle in position. The ink jet head of this embodiment is
Short time from time t4 to stabilization, good frequency response
It is. Next, W4 will be described. From time t1
At time t2, the meniscus 69 is retracted. time
From time t2 to time t3, the movement of the first pressure plate 6 stops.
Stops, but the meniscus 70 shrinks due to the inertia of the ink.
Ink flow is generated in the direction in which the ink flows. This meniscus 7
The reduction speed of 0 is the reduction speed of the meniscus 70 shown in W3.
Is equivalent to From time t3 to time t4, the meniscus
Although the scum 73 is pushed out of the nozzle 2,
Do not eject as ink droplets due to the effect of surface tension.
The meniscus vibrates minutely. This minute vibration
The effect of stirring the ink on the surface of the meniscus formed inside
Have fruit. The meniscus 73 gradually decreases after time t4.
The vibrations attenuate and settle. Next, W5 will be described. From time t1
At time t2, the meniscus 86 does not vibrate. This reason
The reason is that at the same time when the first pressure chamber 9 expands and deforms,
This is because the pressure chamber 8 is reduced and deformed. Time from time t2
The meniscus 87 is pushed out of the nozzle 2 over t3.
Is done. However, overcoming the surface tension of the ink
Do not have kinetic energy large enough to fly as a droplet
No. From time t3 to time t4, the meniscus 88 almost disappears.
It becomes a state of calm. FIG. 13 shows an ink jet head of the present invention.
It is a perspective view showing another Example. 101 is a nozzle
The nozzles are linearly arranged on the nozzle plate 100.
The ink jet head is provided with the nozzle plate 100 and the first
Frame 103, film 104, and second frame 10
5 are laminated and joined. 10
Reference numeral 2 denotes an ink supply pipe, which is an ink tank not shown.
Is supplied to the inkjet head.
Reference numeral 106 denotes an FPC from a circuit board (not shown).
It serves to transmit a drive signal for driving T108.
Add FIG. 14 shows the ink jet printer described with reference to FIG.
It is sectional drawing of a head. In the nozzle plate 100,
A horn-shaped nozzle 101 is formed. 11
Reference numeral 5 denotes a vibrator and pressure generating means. Vibrator 115
Is formed by laminating PZT 108 and elastic plate 109
ing. The vibrator 115 has one end fixed and the other end self-
It has a cantilevered structure. Fixed end is spacer 1
07 and the nozzle plate 100 via the FPC 106
It is sandwiched by one frame 103. The free end is a nose
Nozzle 10 with a small gap 114
1. PZT108
When pressure is applied, the vibrator 115 performs radial vibration. This
Radius vibration of the vibrator 115
This is a vibration that deforms in the direction. Also, for the nozzle 101
The vibrators 115 are configured to correspond one-to-one.
You. The laminated PZT110 is also a pressure generating means, and has one end
2 and the other end of the film 104
Is joined to. A not-shown rotation is applied to the electrodes 111 and 112.
When a voltage from the road base is applied, the laminated PZT 110
It expands and deforms. This deformation is applied via the film 104
This causes a change in the volume of the force chamber 113. Inkjet head
Forming a plurality of stacked PZTs 110 per one node
In the present embodiment, one stacked PZT 11
Only 0 is used. In addition, the minute gap 114 and the nozzle
101 is filled with ink. The ink jet head of this embodiment has a laminated structure.
Due to the use of PZT110, the generated pressure of 5 atm or more
The characteristic is that it can be obtained. Also, the second pressure generating means and
To use the vibrator 115 that vibrates in the radius.
The absolute displacement amount on the nozzle 101 is increased (for example, 10 μm).
m). Therefore, due to the amplitude of the vibrator 115,
Since the acoustic impedance of the chirp 2 can be controlled greatly,
Even if the pressure of the laminated PZT110 is large,
The feature is that ink drops can be ejected. This embodiment is compared with the embodiment shown in FIG.
, The pressure chamber 113 corresponds to the first pressure chamber 9,
Reference numeral 114 corresponds to the second pressure chamber 8. Also, the laminate P
ZT110 is in the first PZT6, and vibrator 115 is in the second PZT6.
Each corresponds to PZT5. Therefore, the driving method
The method can be performed by the method shown in FIGS. The ink jet head driving method of the present invention
Is a first pressure chamber to which the ink in the ink tank is supplied.
A second pressure chamber communicating with the first pressure chamber; and a second pressure chamber.
A first pressure chamber having a plurality of nozzles communicating with the power chamber;
Are commonly connected to each other, and the first pressure chamber
Is the first pressure generating means, and the second pressure chamber is the second pressure generating means.
In a method of driving an ink jet head having a generating means,
At the timing of ejecting ink droplets from the nozzles.
That is, the first and second pressure generating means are simultaneously driven,
Outside the timing of ejecting ink droplets from the nozzle
Drives only the first pressure generating means to operate the inside of the nozzle.
Vibration to the extent that scass is not discharged
All nozzles, regardless of whether ink droplets are ejected or not
And a first pressure generating means commonly communicating with the second pressure chamber.
By driving, discharge is performed using one pressure generating means.
Efficient meniscus of all nozzles that do not perform ejection operation
It is possible to constantly vibrate constantly. Therefore, complex
Increase the amount of ink near all nozzle openings without using a drive circuit
A configuration that suppresses viscosity and can eject ink droplets at high frequencies
It has the effect that it can be maintained for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an inkjet head according to a first embodiment of the present invention. FIG. 2 is a plan view for explaining a shape of an ink flow path on a substrate of the inkjet head according to the first embodiment of the present invention. FIG. 3 is a sectional view of the ink jet head according to the first embodiment of the present invention. FIG. 4 is a diagram showing driving waveforms for explaining a first embodiment of the inkjet head driving method of the present invention. FIGS. 5A to 5C are diagrams showing the flow of ink inside the inkjet head which occurs during the ejection operation in the first embodiment of the inkjet head driving method of the present invention. FIGS. 6A to 6C are diagrams showing the flow of ink inside the inkjet head which occurs during a non-ejection operation in the first embodiment of the inkjet head driving method of the present invention. FIG. 7 shows a first example of the inkjet head driving method of the present invention.
6 is a graph showing a time displacement of a nozzle meniscus in the example. FIG. 8 is a diagram showing driving waveforms for explaining a second embodiment of the inkjet head driving method of the present invention. FIGS. 9A to 9C are diagrams showing the flow of ink inside the ink jet head during a non-ejection operation in the second embodiment of the ink jet head driving method of the present invention. FIGS. 10A to 10C are diagrams showing the flow of ink inside the inkjet head which occurs during a non-ejection operation in the second embodiment of the inkjet head driving method of the present invention. FIGS. 11A to 11C are diagrams showing the flow of ink inside the inkjet head which occurs during another non-ejection operation in the second embodiment of the inkjet head driving method of the present invention. FIG. 12 is a graph showing a time displacement of a nozzle meniscus in a second embodiment of the inkjet head driving method of the present invention. FIG. 13 is a perspective view of an inkjet head according to a second embodiment of the present invention. FIG. 14 is a sectional view of an inkjet head according to a second embodiment of the present invention. FIG. 15 is a cross-sectional view of an inkjet head of Conventional Example 1. FIG. 16 is a plan view illustrating an ink flow path of an ink jet head of Conventional Example 2. FIG. 17 is a cross-sectional view of an inkjet head of Conventional Example 3. [Description of Signs] 1 Base 2 Nozzle 3 Pressure plate 5 Second PZT 6 First PZT 8 Second pressure chamber 9 First pressure chamber

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055

Claims (1)

(57) [Claim 1] The first ink tank is supplied with ink.
It has a pressure chamber, a second pressure chamber of the first pressure chamber and communicating, and said second nozzles communicating with the pressure chamber, wherein
A plurality of the second pressure chambers are commonly connected to the first pressure chamber.
A method for driving an ink jet head comprising: a first pressure generating means in the first pressure chamber; and a second pressure generating means in the second pressure chamber. At the timing of discharging the ink, the first and second pressure generating means are simultaneously driven. Outside the timing of discharging the ink droplets from the nozzle, only the first pressure generating means is driven and the meniscus in the nozzle is discharged. A method for driving an ink-jet head, characterized in that the ink-jet head is vibrated to such an extent that ink is not ejected.