JP2003200572A - Liquid ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder, more widely a liquid injector, in which a more stable ejection control of ink drop can be realized by preventing occurrence of resonance phenomenon in a high frequency region while taking account of the eigen frequency of a recording head. <P>SOLUTION: The liquid injector comprises a head member 10 having a nozzle opening 13, means 15 for varying the ink pressure at the nozzle opening part, means for generating a driving pulse based on ejection data, and a control body section for driving the pressure varying means based on the driving pulse. Driving frequency of the pressure varying means based on the driving pulse is regulated to be different from the eigen frequency of the head member or integer times thereof. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejecting apparatus for ejecting a liquid droplet from a nozzle opening, and more particularly to a liquid ejecting apparatus capable of ejecting a liquid droplet more stably.

[0002]

2. Description of the Related Art In an inkjet recording apparatus (a kind of liquid ejecting apparatus) such as an inkjet printer or an inkjet plotter, a recording head (head member) is moved along a main scanning direction and recording paper (print recording medium). Image (character) is recorded on the recording paper by moving the first type) in the sub-scanning direction and ejecting ink droplets from the nozzle openings of the recording head in conjunction with this movement. The ejection of the ink droplets is performed, for example, by expanding and contracting the pressure generating chamber that communicates with the nozzle openings.

The expansion / contraction of the pressure generating chamber is performed, for example, by utilizing the deformation of the piezoelectric vibrator. In such a recording head, the piezoelectric vibrator is deformed in response to the supplied drive pulse, which changes the volume of the pressure chamber, and this volume change causes a pressure fluctuation in the ink in the pressure chamber, causing a change in the nozzle opening. Ink droplets are ejected.

In such a recording apparatus, a drive signal formed by connecting a plurality of drive pulses in series is generated. on the other hand,
Print data including gradation information is transmitted to the recording head.
Then, based on the transmitted print data, only necessary drive pulses are selected from the drive signals and supplied to the piezoelectric vibrator. As a result, the amount of ink droplets ejected from the nozzle opening is changed according to the gradation information.

More specifically, for example, unrecorded print data (gradation information 00), small dot print data (gradation information 01), medium dot print data (gradation information 10), and large data. 4 consisting of dot print data (gradation information 11)
In a printer in which gradations are set, ink droplets having different ink amounts are ejected according to each gradation.

[0006]

By the way, recently, in order to realize higher speed recording, it is required to eject ink droplets at an extremely high frequency.

On the other hand, the recording head for ejecting ink drops is
It is a mechanical structural member and has a so-called natural frequency. When a vibration of the natural frequency is applied to the recording head, a resonance phenomenon occurs, and there is a frequency band in which ink droplet ejection control from the recording head becomes unstable.

Particularly, in the resonance phenomenon occurring in the high frequency region, since the resonance energy is large, the ink droplet ejection control may become extremely unstable.

The present invention has been made in consideration of such a point, and in consideration of the natural frequency of the recording head, the occurrence of a resonance phenomenon is prevented particularly in a high frequency region, so that the ink is more stable. An object of the present invention is to provide an ink jet recording apparatus, which is capable of realizing droplet ejection control, and a liquid ejecting apparatus in general.

[0010]

According to the present invention, there is provided a head member having a nozzle opening, a pressure changing means for changing the pressure of the liquid in the nozzle opening portion, and a drive pulse generating means for generating a drive pulse based on ejection data. And a control body for driving the pressure fluctuation means based on the drive pulse, wherein the driving frequency of the pressure fluctuation means by the driving pulse is a natural frequency of the head member and an integer multiple of the natural frequency. The liquid ejecting apparatus is characterized in that it is adjusted so as to be different from the value.

According to the present invention, the driving frequency of the pressure varying means is adjusted so that the natural frequency of the head member and the integral multiple of the natural frequency are adjusted differently. The head member is prevented from resonating, and the liquid droplets can be ejected more stably.

[0012] Preferably, the driving frequency of the pressure fluctuation means by the driving pulse is 7.2 kHz or more. In such a high frequency region, the energy of the resonance phenomenon can be large, and thus the prevention of the resonance phenomenon according to the present invention brings a more remarkable effect.

Preferably, the liquid ejecting apparatus further comprises gradation data setting means for setting one selected gradation data from a plurality of gradation data based on the ejection data, and drive signal generating means for generating an ejection drive signal. And the ejection drive signal is a periodic signal having a plurality of pulse waveforms, and the drive pulse generation means generates an ejection drive signal from each gradation data based on the selected gradation data and the ejection drive signal. A rectangular pulse train corresponding to one cycle is generated, and a drive pulse is generated by ANDing the rectangular pulse train and the ejection drive signal.

Specifically, for example, a plurality of gradation data have small dot data and large dot data, and the ejection drive signal is n or more at least 2 in one cycle. Which is a periodic signal having a pulse waveform for droplets, which separates and ejects a small liquid droplet from a nozzle opening,
The drive pulse generation means, based on the ejection drive signal,
When the selected gradation data is data for small dots, only one or more p pulse waveforms for small droplets are used as drive pulses, and when the selected gradation data is data for large dots, it is larger than p and n.
The following q droplet pulse waveforms are used as drive pulses, and the frequency corresponding to the appearance interval of any two adjacent droplet pulse waveforms is the natural frequency of the head member or its integer. It is adjusted to be different from the double value.

Alternatively, the plurality of gradation data have small dot data and large dot data, and the ejection drive signal is a small dot for ejecting a small liquid droplet from the nozzle opening in one cycle. Is a periodic signal having a pulse waveform for a large dot for ejecting a large liquid droplet from a nozzle opening, and the drive pulse generation means is for selecting a small dot for which the selected gradation data is based on the ejection drive signal. When it is data, the pulse waveform for small dots is used as a drive pulse, and when the selected gradation data is data for large dots, the pulse waveform for large dots is used as a drive pulse. The frequency corresponding to the appearance interval of the pulse waveform is adjusted so as to be different from the natural frequency of the head member or a value that is an integral multiple thereof.

Alternatively, the plurality of gradation data have dot ejection data and microvibration data, and the ejection drive signal is a dot pulse for ejecting a liquid drop from a nozzle opening in one cycle. A periodic signal having a waveform and a pulse waveform for micro-vibration that slightly vibrates the liquid in the nozzle opening portion without ejecting liquid droplets from the nozzle opening,
The drive pulse generation means, based on the ejection drive signal,
When the selected gradation data is dot ejection data, the dot pulse waveform is used as a drive pulse, and when the selected gradation data is microvibration data, the microvibration pulse waveform is used as a drive pulse. The frequency corresponding to the appearance interval of any two adjacent pulse waveforms is adjusted to be different from the natural frequency of the head member or an integral multiple thereof.

Further, according to the present invention, a head member having a nozzle opening, a pressure changing means for changing the pressure of the liquid in the nozzle opening portion, a drive pulse generating means for generating a drive pulse based on ejection data, and the drive. A method for manufacturing a liquid ejecting apparatus comprising: a control main body that drives a pressure varying means based on a pulse; a calculating step of calculating a natural frequency of a head member; And a step of adjusting the driving frequency so that the driving frequency is different from the calculated natural frequency of the head member and an integral multiple thereof.

According to the present invention, since the driving frequency of the pressure varying means is adjusted so that the natural frequency of the head member and the integral multiple of the natural frequency are different from each other, the head is driven by driving the pressure varying means. The member is prevented from resonating,
It is possible to manufacture a liquid ejecting apparatus that ejects liquid drops more stably.

Preferably, in the adjusting step, the driving frequency of the pressure fluctuation means by the driving pulse is 7.2 kHz.
The above is set.

Further, the head member has a plurality of nozzle openings forming two parallel nozzle rows, a plurality of pressure chambers communicating with each nozzle opening to form two pressure chamber rows, and the two pressures. And a center rib portion that is interposed between the chamber rows and extends on the side opposite to the nozzle opening, the calculation step includes a step of calculating the natural frequency of the center rib portion. It is preferable that

When the head member has the above-mentioned structure, the natural frequency of the central rib portion is dominant in determining the natural frequency of the head member. It is useful to calculate For example, it is possible to allow the natural frequency of the central rib portion to be simply treated as the natural frequency of the head member.

Further, according to the present invention, a head member having a nozzle opening, a pressure changing means for changing the pressure of the liquid in the nozzle opening portion, a drive pulse generating means for generating a drive pulse based on ejection data, and the drive A method for manufacturing a liquid ejecting apparatus, comprising: a control main body that drives a pressure changing means based on a pulse; a measuring step of measuring a natural frequency of a head member; And a step of adjusting the driving frequency so as to be different from the measured natural frequency of the head member and a value that is an integral multiple thereof.

According to the present invention, the driving frequency of the pressure varying means is adjusted so that the natural frequency of the head member and the integral multiple of the natural frequency are different from each other. The member is prevented from resonating,
It is possible to manufacture a liquid ejecting apparatus that ejects liquid drops more stably.

Preferably, in the adjusting step, the driving frequency of the pressure fluctuation means by the driving pulse is 7.2 kHz.
The above is set.

Further, the head member has a plurality of nozzle openings forming two parallel nozzle rows, a plurality of pressure chambers communicating with each nozzle opening to form two pressure chamber rows, and the two pressures. And a central rib portion which is interposed between the chamber rows and extends on the side opposite to the nozzle opening, the measuring step includes a step of measuring a natural frequency of the central rib portion. It is preferable that

When the head member has the above-described structure, the natural frequency of the central rib portion is dominant in determining the natural frequency of the head member. It is useful to measure For example, it is possible to allow the natural frequency of the central rib portion to be simply treated as the natural frequency of the head member.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view of an ink jet printer 1 which is a liquid ejecting apparatus of this embodiment. In the inkjet printer 1, the carriage 2 is movably attached to the guide member 3. The carriage 2 is connected to a timing belt 6 that is stretched between a drive pulley 4 and an idle pulley 5. The drive pulley 4 is joined to the rotary shaft of the pulse motor 7. With the above configuration, the carriage 2 is moved in the width direction of the recording paper 8 (main scanning) by driving the pulse motor 7.
It is supposed to be done.

A recording head 10 (head member) is attached to the surface (lower surface) of the carriage 2 facing the recording paper 8.

Next, the recording head 10 will be described.
As shown in FIG. 2, the recording head 10 includes a comb-teeth-shaped piezoelectric vibrator 15 inserted from one opening into a storage chamber 72 of a box-shaped case 71 made of, for example, plastic, and a comb-teeth-shaped tip portion. 15a faces the other opening. The flow path unit 7 is provided on the surface (lower surface) of the case 71 on the other opening side.
4 are joined, and the comb-teeth-shaped tip portions 15a are abutted and fixed to predetermined portions of the flow path unit 74, respectively.

In the piezoelectric vibrator 15, a plate-shaped vibrator plate in which the common internal electrodes 15c and the individual internal electrodes 15d are alternately laminated with the piezoelectric body 15b interposed therebetween is cut into a comb shape corresponding to the dot formation density. Is configured. Then, by applying a potential difference between the common internal electrode 15c and the individual internal electrode 15d, each piezoelectric vibrator 15 expands and contracts in the vibrator longitudinal direction orthogonal to the stacking direction.

The flow channel unit 74 is constructed by laminating the nozzle plate 14 and the elastic plate 77 on both sides with the flow channel forming plate 75 interposed therebetween.

The flow path forming plate 75 communicates with a plurality of nozzle openings 13 formed in the nozzle plate 14, and a plurality of pressure generating chambers 16 are arranged in a row with a pressure generating chamber partition wall therebetween.
It is a plate material in which a plurality of ink supply portions 82 that communicate with at least one end of each pressure generation chamber 16 and an elongated common ink chamber 83 that communicates with all the ink supply portions 82 are formed. For example, an elongated common ink chamber 83 is formed by etching a silicon wafer, and the pressure generating chamber 16 is formed along the longitudinal direction of the common ink chamber 83 so that the nozzle opening 1 is formed.
The groove-shaped ink supply portion 82 may be formed between the pressure generation chambers 16 and the common ink chamber 83 in accordance with the pitch of 3. In this case, the ink supply unit 82 is connected to one end of the pressure generating chamber 16, and the nozzle opening 13 is arranged near the end opposite to the ink supply unit 82. Further, the common ink chamber 83 is a chamber for supplying the ink stored in the ink cartridge to the pressure generating chamber 16, and the ink supply pipe 84 communicates with substantially the center in the longitudinal direction thereof.

The elastic plate 77 is laminated on the surface of the flow path forming plate 75 on the side opposite to the nozzle plate 14, and the stainless plate 8
A polymer film such as PPS is provided on the lower surface side of the elastic film 8
8 is a laminated double structure. And
The island portion 89 for abutting and fixing the piezoelectric vibrator 15 is formed by etching the stainless plate 87 in the portion corresponding to the pressure generating chamber 16.

In the recording head 10 having the above structure,
By extending the piezoelectric vibrator 15 in the vibrator longitudinal direction, the island portion 89 is pressed toward the nozzle plate 14, the elastic film 88 around the island portion 89 is deformed, and the pressure generating chamber 16 contracts. When the piezoelectric vibrator 15 is contracted in the longitudinal direction from the contracted state of the pressure generation chamber 16, the elasticity of the elastic film 88 causes the pressure generation chamber 16 to expand. By temporarily expanding and then contracting the pressure generating chamber 16, the ink pressure in the pressure generating chamber 16 increases and ink droplets are ejected from the nozzle openings 13.

That is, in the recording head 10, the capacity of the corresponding pressure chamber 16 changes as the piezoelectric vibrator 15 is charged and discharged. By utilizing such pressure fluctuation of the pressure chamber 16, ink droplets are ejected from the nozzle opening 13,
The meniscus (the free surface of the ink exposed at the nozzle opening 13) can be slightly vibrated.

It is also possible to use a so-called flexural vibration mode piezoelectric vibrator in place of the longitudinal vibration vibration mode piezoelectric vibrator 15 described above. The flexural vibration mode piezoelectric vibrator is a piezoelectric vibrator that contracts the pressure chamber by deformation due to charging and expands the pressure chamber by deformation due to discharging.

The recording head 10 is preferably a multicolor recording head capable of recording a plurality of different colors. The multi-color recording head includes a plurality of head units, and the type of ink used is set for each head unit.

For example, in a recording head having four head units, a black head unit capable of ejecting black ink, a cyan head unit capable of ejecting cyan ink, and a magenta head unit capable of ejecting magenta ink. , And a yellow head unit capable of ejecting yellow ink.

Each head unit has, for example, as shown in FIG. 3, two parallel rows of nozzle openings 13A and 13B, and a plurality of pressure chambers 16 are provided in each nozzle opening 1.
Two pressure chamber rows 16A and 16B are formed so as to communicate with No. 3, and a central rib portion 18 is interposed between the two pressure chamber rows 16A and 16B and extends to the opposite side of the nozzle opening 13. .

The printer 1 constructed as described above synchronizes with the main scanning of the carriage 2 during the recording operation.
Ink is ejected from the recording head 10 as an ink droplet. On the other hand, the platen is rotated in association with the reciprocating movement of the carriage 2 to move the recording paper 8 in the paper feeding direction (that is, sub-scanning). As a result, images, characters, etc. based on the recording data are recorded on the recording paper 8.

Next, the electrical construction of the ink jet printer will be described. As shown in FIG. 4, the printer 1 includes a printer controller 23 and a print engine 2.
4 and.

The printer controller 23 includes an external interface (external I / F) 25, a RAM 26 for temporarily storing various data, a ROM 27 for storing control programs and the like, and a control section 28 including a CPU and the like.
And an oscillator circuit 29 for generating a clock signal (CK),
A drive signal generation circuit 30 that generates a drive signal (COM) to be supplied to the recording head 10, a drive signal, and dot pattern data (bitmap data) developed based on print data (print data) are printed. Internal interface (internal I / F) 3 to send to engine 24
1 and.

The external I / F 25 receives print data composed of, for example, a character code, a graphic function, image data, etc. from a host computer (not shown) or the like. In addition, the busy signal (BUSY) and acknowledge signal (ACK) are transmitted through the external I / F 25.
It is output to the host computer or the like.

Further, the external I / F 3 of this embodiment is
It is connected to an interface device 100 such as a keyboard that functions as an image quality mode setting unit that sets an image quality mode (ejection mode) relating to recording accuracy on the recording paper 8 (recording medium) according to the present embodiment.

The RAM 26 has a reception buffer, an intermediate buffer, an output buffer and a work memory (not shown). The receiving buffer temporarily stores the print data received via the external I / F 25, the intermediate buffer stores the intermediate code data converted by the control unit 28, and the output buffer stores the dot pattern data. Memorize Here, the dot pattern data is print data obtained by decoding (translating) intermediate code data (for example, gradation data).

The ROM 27 stores font data, graphic functions, etc. in addition to a control program (control routine) for performing various data processing.

The control unit 28 performs various controls according to the control program stored in the ROM 27. For example, the print data in the reception buffer is read, the print data is converted into intermediate code data, and the intermediate code data is stored in the intermediate buffer. In addition, the control unit 28
Analyzes the intermediate code data read from the intermediate buffer and refers to the font data and the graphic function stored in the ROM 27 to develop (decode) the dot pattern data. Then, the control unit 28 stores the dot pattern data in the output buffer after performing the necessary decoration processing. Each dot pattern data consists of 2-bit data in this case as gradation information. That is, the control unit 28 functions as a gradation data setting unit.

When the recordable dot pattern data for one line is obtained by one main scan of the recording head 10, the dot pattern data for one line is sequentially recorded from the output buffer through the internal I / F 31. It is output to the head 10. When one line of dot pattern data is output from the output buffer, the expanded intermediate code data is erased from the intermediate buffer, and expansion processing is performed on the next intermediate code data.

Further, the control section 28 constitutes a part of the timing signal generating means, and the latch signal (LAT) and the channel signal (C) are sent to the recording head 10 through the internal I / F 31.
H) is supplied. These latch signals and channel signals define the supply start timing of the pulse signals forming the drive signal (COM).

On the other hand, the print engine 2 includes a paper feed motor 35 as a paper feed mechanism, a pulse motor 7 as a carriage feed mechanism, and an electric drive system 3 for the recording head 10.
3 is included. The paper feed motor 35 rotates the platen 34 (see FIG. 1) to move the recording paper 8, and the pulse motor 7 causes the carriage 2 to travel via the timing belt 6.

The electric drive system 33 of the recording head 10 is shown in FIG.
As shown in, a shift register circuit including a first shift register 36 and a second shift register 37, a latch circuit including a first latch circuit 39 and a second latch circuit 40, a decoder 42, a control logic 43, and a level shifter. 44, a switch circuit 45, and the piezoelectric vibrator 15.

As shown in FIG. 5, the shift registers, the latch circuits, the decoders, the switch circuits, and the piezoelectric vibrators are respectively provided with the first shift registers 36A to 36A provided for each nozzle opening 13 of the recording head 10. 36N, second shift registers 37A to 37N, first latch circuit 39
A to 39N, second latch circuits 40A to 40N, recorders 42A to 42N, switch circuits 45A to 45N, and piezoelectric vibrators 15A to 15N.

The recording head 10 discharges ink droplets based on the print data (gradation information) from the printer controller 23 by such an electric drive system 33. The print data (SI) from the print controller 23 is serially transmitted from the internal I / F 31 to the first shift register 36 and the second shift register 37 in synchronization with the clock signal (CK) from the oscillation circuit 29.

The print data from the printer controller 23 is 2-bit data as described above. Specifically, for four gradations of non-printing, small dot, medium dot, and large dot, non-printing is (00), small dot is (01), and medium dot is (10), The large dots are represented by (11).

Such print data is set for each dot, that is, for each nozzle opening 13. Then, the lower bit data for all the nozzle openings 13 is input to the first shift register 36 (36A to 36N), and the upper bit data for all the nozzle openings 13 is input to the second shift register 37 (37A to 37N). To be done.

As shown in FIG. 4, the first shift register 3
A first latch circuit 39 is electrically connected to 6. Similarly, a second latch circuit 40 is electrically connected to the second shift register 37. When the latch signal (LAT) from the print controller 23 is input to each of the latch circuits 39 and 40, the first latch circuit 39
Latches the lower bit data of the print data, and the second latch circuit 40 latches the upper bit of the print data.

As described above, the circuit unit including the first shift register 36 and the first latch circuit 39 and the circuit unit including the second shift register 37 and the second latch circuit 40 each function as a memory circuit. That is, these circuit units temporarily store the print data (gradation information) before being input to the decoder 42.

The print data latched by the latch circuits 39 and 40 are input to the decoders 42A to 42N. The decoder 42 translates the 2-bit print data (gradation data) to generate pulse selection data (pulse selection information). The pulse selection data is usually composed of a plurality of bits, which is larger than the gradation data, and each bit is a drive signal (COM).
It corresponds to each pulse waveform which constitutes. The supply / non-supply of the drive pulse waveform to the piezoelectric vibrator 15 is selected according to the content of each bit (for example, (0), (1)). In addition, drive signal (COM)
The details of supplying the drive pulse waveform will be described later.

On the other hand, the decoder 42 has a control logic 4
The timing signal from 3 is also input. Control logic 4
3 functions as a timing signal generating means together with the control unit 28, and a latch signal (LAT) and a channel signal (C
H) to generate a timing signal.

The pulse selection data translated by the decoder 42 is sequentially input from the upper bit side to the level shifter 44 each time the timing defined by the timing signal arrives. For example, the data of the most significant bit of the pulse selection data is input to the level shifter 44 at the first timing in the recording cycle, and the data of the second bit of the pulse selection data is input to the level shifter 44 at the second timing.

The level shifter 44 functions as a voltage amplifier, and when the pulse selection data is "1", it outputs an electric signal boosted to a voltage capable of driving the switch circuit 45, for example, a voltage of about several tens of volts.

The pulse selection data of "1" boosted by the level shifter 44 is supplied to the switch circuit 45 which functions as a drive pulse generating means and a control body. The switch circuit 45 selects a drive pulse waveform included in the drive signal (COM) to generate a drive pulse based on the pulse selection data generated by translating the print data, and at the same time, outputs the drive pulse to the piezoelectric vibrator 15 Is to be supplied to. Therefore, the drive signal (COM) from the drive signal generation circuit 30 is supplied to the input side of the switch circuit 45, and the piezoelectric vibrator 15 is connected to the output side thereof.

The pulse selection data controls the operation of the switch circuit 45. For example, while the pulse selection data applied to the switch circuit 45 is “1”, the switch circuit 45 is in the connected state and the drive pulse of the drive signal is supplied to the piezoelectric vibrator 15. As a result, the potential level of the piezoelectric vibrator 15 changes.

On the other hand, while the pulse selection data applied to the switch circuit 45 is "0", the level shifter 44 does not output an electric signal for operating the switch circuit 45.
Therefore, the switch circuit 45 is turned off, and the drive pulse of the drive signal is not supplied to the piezoelectric vibrator 15. While the pulse selection data is “0”, the piezoelectric vibrator 1
5 maintains the potential level immediately before the pulse selection data is switched to "0".

Next, the drive signal (COM) generated by the drive signal generation circuit 30 and ink droplet ejection control by this drive signal will be described in detail.

FIG. 6 is a diagram showing an example of the drive signal, FIG. 7 is a diagram explaining drive pulses in the drive signal of FIG. 6, and FIG.
Is a diagram showing another example of the drive signal, and FIG. 9 is a diagram for explaining drive pulses in the drive signal of FIG.

The drive signal A shown in FIG. 6 includes a first pulse signal PS11 arranged in the period T11, a second pulse signal PS12 arranged in the period T12, and a third pulse signal PS13 arranged in the period T13. Are connected in series,
It is a pulse train waveform signal repeatedly generated in the recording cycle TA. In this case, the frequency of the recording cycle TA is 12 × 3 kHz
z. In the drive signal A, the first pulse signal PS1
1 is the first drive pulse DP1 and the second pulse signal P1
S12 is the second drive pulse DP2, and the third pulse signal PS13 is the third drive pulse DP3.

The first drive pulse DP1, the second drive pulse DP2, and the third drive pulse DP3 have the same waveform shape, and are signals capable of ejecting ink droplets independently.

That is, each drive pulse DP1, DP2
The DP3 includes a first charging element P11 that raises the potential from the intermediate potential VM to the highest potential VH along the gradient θ11, and a first hold element P1 that maintains the highest potential VH for a short time.
2 and the first discharge element P that drops the potential from the highest potential VH to the lowest potential VL along the steep gradient θ12 in a very short time.
13 and a second hold element P14 that maintains the lowest potential
And the intermediate potential VM from the lowest potential VL along the gradient θ13.
And a second charging element P15 that raises the potential up to.

When each of these drive pulses is supplied to the piezoelectric vibrator 15, ink droplets of a quantity capable of forming a small dot are ejected from the nozzle opening 13.

More specifically, when the first charging element P11 is supplied and the piezoelectric vibrator 15 is charged from the intermediate potential VM, the volume of the pressure generating chamber 16 expands from the reference volume to the maximum volume. Then, the first discharge element P13 causes the pressure generating chamber 16 to rapidly contract to the minimum volume. The contracted state of the pressure generating chamber 16 is the second hold element P14.
Is maintained over the period that it is being supplied. By rapidly contracting the pressure generating chamber 16 and maintaining the contracted state, the ink pressure in the pressure generating chamber 16 is rapidly increased and the nozzle opening 1
Ink droplets are ejected from 3. The amount of ink droplets ejected at this time is, for example, about 13 pL. Then, the second charging element P15 expands and restores the pressure generating chamber 16 so as to converge the vibration of the meniscus in a short time.

At this time, as shown in FIG. 7, the piezoelectric vibrator 1
By increasing or decreasing the number of drive pulses supplied to 5,
Gradation control can be performed. For example, drive pulse 1
Small dots can be recorded by supplying two driving pulses, medium dots can be recorded by supplying two driving pulses, and large dots can be recorded by supplying three driving pulses.

When the piezoelectric vibrator 15 is deformed, the recording head 10 is deformed by receiving the reaction force f of the deformation force. Here, the main feature of the present embodiment is that the driving frequency of the piezoelectric vibrator 15 (pressure generating means) by the driving pulse is
The natural frequency F related to the deformation of the recording head 10 due to the reaction force f and the value nF which is an integral multiple of the natural frequency F are adjusted to be different (n is an integer).

Specifically, as shown in FIG. 6, the frequency 1 / g corresponding to the appearance intervals g11, g12, g13 of two adjacent arbitrary waveforms of the pulse waveforms DP1, DP2, DP3.
11, 1 / g12 and 1 / g13 are adjusted so as to be different from the natural frequency F of the recording head 10 and the value nF which is an integral multiple thereof.

For example, in the case of the head unit as shown in FIG. 3, the central rib portion 18 extending between the two nozzle rows 13A and 13B approximately reacts from the nozzle plate 14 side as shown in FIG. Receive force f.

In this case, as shown exaggeratedly in FIG. 10B, the central rib portion 18 is flexibly deformed. Regarding this flexural deformation, the length (span) of the central rib portion 18 is L, the Young's modulus (longitudinal elastic modulus) is E, the second moment of area is I, the width is b, the height is h, the distributed load is W, In such a case, it is known that the following equation approximately holds for the amount of deflection (deformation) X.

[0078] ^{X = L 3 × W / (} 48 × E × I) I = b × h 3/12 natural frequency f of the central rib portion 18 to be deformed in this way deflection
Is represented by f = λ / (2 × π × L) × (E / ρ) ^1/2 . Here, ρ is the specific gravity and λ is the frequency coefficient, and λ = π in the first-order deformation mode.

The natural frequency f of the central rib portion 18 thus obtained may be used approximately as the natural frequency of the recording head 10.

The method of obtaining the natural frequency of the central rib portion 18 is not limited to the above approximate calculation formula, and other methods using the finite element method or the like can be adopted.

Alternatively, the natural frequency of the entire recording head 10 may be obtained by using an approximate calculation formula or a finite element method.

Alternatively, the natural frequency of the central rib portion 18 or the natural frequency of the entire recording head 10 may be measured by various experiments after manufacturing the actual machine.

Next, the drive signal B shown in FIG.
1 and the first pulse signal PS21 and the period T21
Second pulse signal PS22 placed in the subsequent period T22
And the in-print micro-vibration pulse signal PS23 arranged in the period T23 after the period T22 are connected in series and are pulse train waveform signals repeatedly generated in the printing cycle TB. In the drive signal B, the first pulse signal PS21 is a small dot drive pulse DP4 (relatively a small dot pulse waveform) for ejecting a small ink droplet from the nozzle opening 13, and the second pulse signal PS22 is a medium pulse from the nozzle opening 13. It is a medium dot drive pulse DP5 (relatively large dot pulse waveform) for ejecting an ink droplet.

The first pulse signal PS21 has an intermediate potential VM.
From the first discharge element P21 that lowers the potential along a potential gradient θ21 that is set relatively gently from
For a predetermined time, a first holding element P22 for maintaining the maximum potential VH for a short period of time, a first charging element P23 for increasing the potential from the minimum potential VH to the maximum potential VH with a predetermined potential gradient θ22, and a second hold element P24 for maintaining the maximum potential VH for a short time. And a second discharge element P25 that lowers the potential from the highest potential VH to the lowest potential VL in a very short time along a steeply set potential gradient θ23, and a third hold that keeps the lowest potential VL for a very short time. Gradient θ from the lowest potential up to the element P26 and the second intermediate potential VM2 set between the intermediate potential VM and the highest potential VH.
24, a second charging element P27 that raises the potential in a very short time, a fourth hold element P28 that maintains the second intermediate potential VM2 for a predetermined time, and a potential that drops along the potential gradient θ25 to the intermediate potential. Third discharge element P for returning to VM
And 29.

In the first pulse signal PS21, the potential gradients θ21, θ22, and θ25 are set to gradients such that ink drops are not ejected.

The second pulse signal PS22 (large dot drive pulse) is generated from the intermediate potential VM to the maximum potential VH by the third charging element P31 which raises the potential at a constant gradient θ26 at which ink droplets are not ejected and the maximum potential VH. A fifth hold element P32 that holds a predetermined time, a fourth discharge element P33 that drops the potential from the highest potential VH to the lowest potential VL with a steep gradient θ27, a sixth hold element P34 that holds the lowest potential VL for a given time, and a lowest Fourth charging element P35 for increasing the potential from the potential VL to the intermediate potential VM with the gradient θ28
It consists of and.

The intra-printing micro-vibration pulse signal PS23 includes a fifth discharge element P37 for decreasing the potential from the intermediate potential VM along the potential gradient θ29, and a seventh hold element P38 for maintaining the second lowest potential VL2 for a predetermined time. Second lowest potential VL
And a fifth charging element P39 that raises the potential from 2 to the intermediate potential VM with a predetermined potential gradient θ30.

Of the ejection drive signals B as described above, the first
When the pulse signal PS21 portion is supplied to the piezoelectric vibrator 15, small ink droplets capable of forming small dots are generated in the nozzle opening 13.
Is discharged from.

More specifically, when the first discharge element P21 is supplied and the piezoelectric vibrator 15 is discharged from the intermediate potential VM, the volume of the pressure generating chamber 16 is equal to the reference volume (corresponding to the intermediate potential VM). Volume) gradually decreases. Then, by the first hold element P22, the pressure generating chamber 16 maintains the minimum volume corresponding to the minimum potential VL for a predetermined time.
Then, by the first charging element P23, the pressure generating chamber 16
Expands to a maximum volume corresponding to the highest potential VH.

Subsequently, the pressure generating chamber 16 is rapidly contracted from the maximum volume to the minimum volume by the second discharge element P25. Due to this contraction, the ink pressure in the pressure generating chamber 16 increases, and ink droplets are ejected from the nozzle openings 13. Since the supply time of the second discharging element P25 is set to be extremely short, the pressure generating chamber 16 is set by the second charging element P27.
Quickly expands. As a result, the amount of ink droplets ejected from the nozzle opening 13 is limited to a small amount, for example, 3 to 9 pL.

Then, the volume of the pressure generating chamber 16 corresponding to the second intermediate potential VM2 is maintained for a predetermined time by the fourth hold element P28, and the pressure generating chamber 16 is converged by the third discharging element P29 in a short time to converge the vibration of the meniscus. Shrink 16

On the other hand, when the portion of the second pulse signal PS22 is supplied to the piezoelectric vibrator 15, the medium ink droplet corresponding to the medium dot is ejected from the nozzle opening 13.

More specifically, when the third charging element P31 is supplied and the piezoelectric vibrator 15 is charged from the intermediate potential VM, the volume of the pressure generating chamber 16 gradually expands from the reference volume. Then, by the fifth hold element P32,
The pressure generating chamber 16 maintains the maximum volume corresponding to the highest potential VH for a short time. After that, by the fourth discharge element P33,
The pressure generating chamber 16 rapidly contracts to the minimum volume corresponding to the lowest potential VL. Due to this contraction, the ink pressure in the pressure generating chamber 16 increases, and ink droplets are ejected from the nozzle openings 13. Here, the state of the minimum volume is maintained for a predetermined time by the sixth hold element P34. As a result, the amount of ink droplets ejected from the nozzle opening 13 becomes, for example, 9 to 15 pL. Subsequently, the fourth charging element P35 causes the pressure generating chamber 16 to expand and return to the reference volume in order to converge the vibration of the meniscus in a short time.

At this time, as shown in FIG. 9, a large dot can be printed by supplying the first pulse signal PS21 and the second pulse signal PS22 in combination.

On the other hand, when the in-print micro-vibration pulse signal PS23 portion is supplied to the piezoelectric vibrator 15, ink droplets are not ejected from the nozzle openings 13 and the ink in the nozzle openings 13 is vibrated slightly.

Also in the drive signal B, as in the case of the drive signal A, the drive frequency of the piezoelectric vibrator 15 (pressure generating means) by the drive pulse is the reaction force f of the recording head 10.
The natural frequency F and the value nF that is an integral multiple of the natural frequency related to the deformation due to (see FIG. 10) are adjusted to be different.

Specifically, as shown in FIG. 8, the frequency 1 / g corresponding to the appearance intervals g21, g22, g23 of two adjacent arbitrary waveforms of the pulse waveforms DP4, DP5, DP6.
21, 1 / g22 and 1 / g23 are adjusted to be different from the natural frequency F of the recording head 10 and the value nF which is an integral multiple thereof.

In the drive signal B as described above, the pulse signal forming the drive signal for ejecting ink droplets is the first pulse signal P.
Since there are only two types, S21 and the second pulse signal PS22, the printing cycle TB can be set relatively short.
As a result, the time required to print one dot can be shortened, and high-quality printing can be performed while maintaining high image quality.

Here, in the present embodiment, dot pattern data for small dots (gradation information 01), dot pattern data for medium dots (gradation information 10) and dot pattern data for large dots (gradation information 11). The pulse selection data generated according to the above will be specifically described.

First, when the drive signal A shown in FIGS. 6 and 7 is used, gradation control is performed by increasing or decreasing the number of drive pulses supplied to the piezoelectric vibrator 15. For example,
Small dots are recorded by supplying one driving pulse, medium dots are recorded by supplying two driving pulses, and large dots are recorded by supplying three driving pulses.

In this case, the decoder 42 responds to the dot pattern data for small dots (gradation information 01), the dot pattern data for medium dots (gradation information 10) and the dot pattern data for large dots (gradation information 11). To generate 3-bit pulse selection data.

Each bit of the 3-bit pulse selection data corresponds to each pulse signal. That is, the most significant bit of the pulse selection data is the first pulse signal PS11.
Corresponding to (first drive pulse DP1), the second bit is the second pulse signal PS12 (second drive pulse DP2).
And the least significant bit corresponds to the third pulse signal PS13.
This corresponds to (third drive pulse DP3).

In this case, pulse selection data (010) is generated from dot pattern data (gradation information 01) of small dots. Similarly, pulse selection data (101) is generated from the dot pattern data (gradation information 10) for medium dots, and the dot pattern data (gradation information 1) for large dots is generated.
Pulse selection data (111) is generated from 1).

When the most significant bit of the pulse selection data is "1", the first timing signal (latch signal) generated at the beginning of the period T11 to the second timing signal (CH) generated at the beginning of the period T12. Until the signal), the switch circuit 45 (driving pulse supply means) is in the connected state. Further, when the second bit is "1", 3 is generated at the beginning of the period T13 from the second timing signal.
The switch circuit 45 remains connected until the second timing signal (CH signal). Similarly, when the least significant bit is "1", the switch circuit 45 is connected between the third timing signal and the timing signal (latch signal) generated at the beginning of the period T11 in the next printing cycle TA. Become.

As a result, only the second drive pulse DP2 is supplied to the corresponding piezoelectric vibrator 15 based on the dot pattern data of the small dots. Similarly, based on the dot pattern data for medium dots, the first drive pulse DP
1 and the third drive pulse DP3 are supplied, and based on the dot pattern data of the large dot, the first drive pulse DP
The first, second drive pulse DP2, and the third drive pulse DP3 are continuously supplied.

As a result, a 13 pL ink droplet is ejected once from the nozzle opening 13 in accordance with the dot pattern data for a small dot, and a small dot is formed on the recording paper 8.
In addition, 13 pL of ink droplets are ejected from the nozzle opening 13 twice in succession corresponding to the dot pattern data of medium dots, and a total of 26 pL of ink droplets are formed on the recording paper 8. Similarly, 13 pL of ink droplets are continuously ejected from the nozzle opening 13 three times corresponding to the dot pattern data of large dots, and a total of 39 pL on the recording paper 8
Large dots are formed by L ink droplets.

Next, the case where the drive signal B having the form shown in FIGS. 8 and 9 is used will be described.

In this case, the decoder 42, in this case, dot ejection data (gradation information 00), dot pattern data for small dots (gradation information 01), dot pattern data for medium dots (gradation information 10) and large dots. 3-bit pulse selection data is generated according to the dot pattern data (gradation information 11).

Each bit of the 3-bit pulse selection data corresponds to each pulse signal. That is, the upper bits of the pulse selection data correspond to the first pulse signal PS21, the middle bits correspond to the second pulse signal PS22,
The lower bit corresponds to the in-print micro-vibration pulse signal PS23.

In this case, the pulse selection data (001) is generated from the data (gradation information 00) without dot recording. Further, pulse selection data (100) is generated from dot pattern data (gradation information 01) of small dots. Then, pulse selection data (010) is generated from the dot pattern data (gradation information 10) of the medium dot,
Pulse selection data (110) is generated from dot pattern data (gradation information 11) of large dots.

When the upper bit of the pulse selection data is "1", the first timing signal (latch signal) generated at the beginning of the period T21 to the second timing signal (CH signal) generated in the period T22. Until then, the switch circuit 45 (driving pulse supply means) is connected. On the other hand, when the middle bit is "1", the switch circuit 45 (driving pulse supply means) is connected from the second timing signal to the third timing signal (CH signal) generated in the period T23. And the lower bit is "1"
In the case of, the switch circuit 45 is connected from the third timing signal to the timing signal (latch signal) generated at the beginning of the period T21 in the next printing cycle.

As a result, only the in-print micro-vibration pulse signal PS23 is supplied to the corresponding piezoelectric vibrator 15 based on the data for which dot recording is not performed. Further, based on the dot pattern data of small dots, the corresponding piezoelectric vibrator 1
Only the first pulse signal PS21 is supplied to 5. Similarly, only the second pulse signal PS22 is supplied based on the dot pattern data for medium dots, and the first pulse signal PS21 and the second pulse signal PS22 are continuously supplied based on the dot pattern data for large dots.

As a result, small ink droplets of 3 to 9 pL are ejected from the nozzle openings 13 corresponding to the dot pattern data of small dots, and small dots are formed on the recording paper 8. Further, medium dots of 9 to 15 pL are ejected from the nozzle openings 13 corresponding to the dot pattern data of medium dots, and medium dots are formed on the recording paper 8. Further, ink droplets of 17 to 30 pL are ejected from the nozzle openings 13 corresponding to the dot pattern data of large dots, and large dots are formed on the recording paper 8. On the other hand, the ink in the nozzle openings 13 is slightly vibrated corresponding to the data not recorded with dots.

Next, the operation of the printer 1 will be described.

The drive signal generation circuit 30 sets the state in which the drive signal A (FIG. 6) can be generated or the state in which the drive signal B (FIG. 8) can be generated according to the setting of the image quality mode or the like. Set.

The decoder 42 also sets a combination of print data (gradation information) and pulse selection data. For example, the decoder 42 sets the image quality mode (driving mode) set based on table information that defines a combination of print data and pulse selection data for each image quality mode (for each drive signal), control information from the control unit 28, and the like. Select the table information corresponding to (Signal).

Subsequently, the printer 1 performs a recording operation based on the set image quality mode (drive signal).

For example, the drive signal generation circuit 30 (drive signal generation means) is configured so that the first drive pulse DP having the same waveform shape is used.
When generating the drive signal A in which the first drive pulse DP2, the third drive pulse DP2, and the third drive pulse DP3 are connected in series, the decoder 42 uses the small dot print data (gradation information 01).
To generate pulse selection data (010),
The pulse selection data (101) is generated by translating the print data (gradation information 10) for medium dots, and the pulse selection data (111) is generated by translating the print data (gradation information 11) for large dots.

The switch circuit 45 (driving pulse supply means) receives the timing signal output from the control logic 43, that is, the latch signal (LA).
T) or the timing of the channel signal (CH), the content of the pulse selection data is referred to, and when the pulse selection data is (1), the drive pulse is applied to the piezoelectric vibrator 15 over the corresponding period. Supply.

As a result, based on the print data of the small dots, only the second drive pulse DP2 is supplied to the piezoelectric vibrator 15, and the small ink droplet having the ink amount of 13 pL is ejected from the nozzle opening 13. Further, based on the print data of the medium dots, the first drive pulse DP1 and the third drive pulse DP1
3 are continuously supplied to the piezoelectric vibrator 15, and a small ink droplet having an ink amount of 13 pL is ejected from the two-droplet nozzle opening 13. Similarly, the first drive pulse DP1, the second drive pulse DP2, and the third drive pulse DP3 are continuously supplied to the piezoelectric vibrator 15 based on the print data of the large dot, and the ink amount of 13 pL is small. 3 drops of ink drops Nozzle opening 1
3 is discharged.

Alternatively, the drive signal generation circuit 30 (drive signal generation means) vibrates the small dot drive pulse DP4 for ejecting a small ink droplet, the medium dot drive pulse DP5 for ejecting a medium ink droplet, and a slight vibration without ejecting ink. When generating the drive signal B in which the drive pulse DP6 for micro-vibration is connected in series, the decoder 42 translates the print data (gradation information 01) for the small dots to obtain the pulse selection data (1
00) and print data for the medium dots (gradation information 1
0) is used to generate pulse selection data (010), translation of large dot print data (gradation information 11) is used to generate pulse selection data (110), and print data without ejection (gradation information 00) To generate pulse selection data (001).

Then, the switch circuit 45 (driving pulse supply means) refers to the content of the pulse selection data every time the timing signal output from the control logic 43 is input, and when the pulse selection data is (1). , Drive pulses are supplied to the piezoelectric vibrator 15 over a corresponding period.

As a result, the small dot drive pulse DP4 is supplied to the piezoelectric vibrator 15 based on the small dot print data, and a small ink droplet having an ink amount of 3 to 9 pL is ejected from the nozzle opening 13. Further, the medium dot drive pulse DP5 is supplied to the piezoelectric vibrator 15 based on the print data of the medium dot, and the medium ink droplet having the ink amount of 9 to 15 pL is ejected from the nozzle opening 13. Similarly, the small dot drive pulse DP4 and the medium dot drive pulse DP5 are continuously supplied to the piezoelectric vibrator 15 based on the print data of the large dot, and the small ink droplet and the medium ink droplet having a total of 17 to 30 pL are generated. It is discharged from the nozzle opening 13. On the other hand, based on the print data without ejection, the micro-vibration drive pulse DP6 is supplied to the piezoelectric vibrator 15, and the ink in the nozzle openings is vibrated slightly.

Regardless of whether the drive signal A or the drive signal B is used, the drive frequency of the piezoelectric vibrator 15 by the drive pulse is the natural frequency F of the flexural deformation of the recording head 10 and the value nF which is an integral multiple thereof. Since they are adjusted differently, even if the driving frequency of the piezoelectric vibrator 15 by the driving pulse is set to a high frequency region of, for example, 10.8 kHz or more,
Ink droplet ejection does not become unstable due to the occurrence of the resonance phenomenon of the recording head 10, that is, more stable ink droplet ejection is realized.

The pressure generating element that changes the volume of the pressure chamber 16 is not limited to the piezoelectric vibrator 15. For example, a magnetostrictive element may be used as a pressure generating element, and the pressure chamber 16 may be expanded and contracted by this magnetostrictive element to generate pressure fluctuations. Alternatively, a heating element may be used as a pressure generating element and The pressure may be changed in the pressure chamber 16 by the bubbles that expand and contract due to heat.

Although the above description has been made with respect to the ink jet recording apparatus, the present invention is broadly applied to all liquid ejecting apparatuses. Examples of liquids include
Besides ink, glue, nail polish, etc. may be used.

[0127]

As described above, according to the present invention,
Since the drive frequency of the pressure fluctuation means is adjusted so that the natural frequency of the head member and the integral multiple of the natural frequency are different, it is possible to prevent the head member from resonating due to the driving of the pressure fluctuation means. The liquid droplets can be ejected more stably.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a sectional view illustrating an internal structure of a recording head.

3A and 3B are diagrams illustrating an internal structure of a head unit, FIG. 3A is a schematic perspective exploded view, and FIG. 3B is a schematic sectional view perpendicular to a central rib portion.

FIG. 4 is a block diagram illustrating an electrical configuration of a printer.

FIG. 5 is a block diagram illustrating an electric drive system of a recording head.

FIG. 6 is a diagram showing an example of a drive signal.

FIG. 7 is a diagram illustrating a drive pulse generated based on the drive signal of FIG.

FIG. 8 is a diagram showing an example of a drive signal.

FIG. 9 is a diagram illustrating drive pulses generated based on the ejection drive signal of FIG.

10A and 10B are diagrams illustrating bending deformation of a central rib portion of the head unit in FIG. 3, FIG. 10A is a schematic cross-sectional view, and FIG. 10B is a schematic front view in which deformation is emphasized.

[Explanation of symbols]

1 Inkjet printer 2 carriage 3 Guide member 4 drive pulley 5 Idling pulley 6 Timing belt 7 pulse motor 8 recording paper 10 recording head 11 ink cartridges 12 ink chamber 13 nozzle opening 14 nozzle plate 15 Piezoelectric vibrator 15a Comb-shaped tip 15b Piezoelectric body 15c common internal electrode 15d Individual internal electrode 16 Pressure chamber 18 Central rib part 23 Printer Controller 24 print engine 25 External interface 26 RAM 27 ROM 28 Control unit 29 Oscillation circuit 30 Drive signal generation circuit 31 Internal interface 33 Electric drive system for recording head 34 Platen 35 Paper feed motor 36 First Shift Register 37 Second Shift Register 39 First Latch Circuit 40 Second latch circuit 42 decoder 43 Control logic 44 level shifter 45 switch circuit 71 cases 72 storage room 74 Channel unit 75 Flow path forming plate 77 Elastic plate 80 nozzle openings 82 Ink supply section 83 Common ink chamber 84 ink supply pipe 87 stainless steel plate 88 Elastic membrane 89 Island section 100 interface equipment

Claims (12)

[Claims] 1. A head member having a nozzle opening, a pressure changing means for changing the liquid pressure at the nozzle opening portion, a drive pulse generating means for generating a drive pulse based on ejection data, and a drive pulse based on the drive pulse. And a control body for driving the pressure fluctuation means, wherein the driving frequency of the pressure fluctuation means by the driving pulse is adjusted so as to be different from the natural frequency of the head member and a value of an integer multiple of the natural frequency. And a liquid ejecting apparatus. 2. The liquid ejecting apparatus according to claim 1, wherein the drive frequency of the pressure varying means based on the drive pulse is 7.2 kHz or more. 3. A gradation data setting means for setting one selected gradation data from a plurality of gradation data based on the discharge data, and a drive signal generating means for generating a discharge drive signal, further comprising: The drive signal is a periodic signal having a plurality of pulse waveforms, and the drive pulse generation means, based on the selected gradation data and the ejection drive signal, forms a rectangle corresponding to one cycle of the ejection drive signal from each gradation data. The liquid ejecting apparatus according to claim 1 or 2, wherein a pulse train is generated, and a drive pulse is generated by ANDing the rectangular pulse train and the ejection drive signal. 4. A plurality of gradation data has small dot data and large dot data, and the ejection drive signal is at least 2 in one cycle.
The driving pulse generating means is a periodic signal having a droplet waveform for ejecting small liquid droplets from the above-mentioned n separated nozzle openings, wherein the drive pulse generation means is based on the ejection drive signal When the selected gradation data is data for large dots, q is a pulse for q droplets larger than p and n or less when the selected gradation data is data for large dots. The waveform is used as the drive pulse, and the frequency corresponding to the interval between the appearance of any two adjacent pulse waveforms for droplets is adjusted so that it is different from the natural frequency of the head member or a value that is an integral multiple thereof. The liquid ejecting apparatus according to claim 3, wherein the liquid ejecting apparatus is provided. 5. A plurality of gradation data has small dot data and large dot data, and the ejection drive signal causes a small liquid droplet to be ejected from a nozzle opening in one cycle. The drive pulse generation means is a periodic signal having a pulse waveform for small dots and a pulse waveform for large dots for ejecting a large liquid droplet from a nozzle opening. When the data is for dots, the pulse waveform for small dots is used as a drive pulse, and when the selected gradation data is for large dots, the pulse waveform for large dots is used as a drive pulse. The liquid ejection according to claim 3, wherein the frequency corresponding to the appearance interval of the two pulse waveforms is adjusted so as to be different from the natural frequency of the head member or a value of an integral multiple thereof. Shooting device. 6. A plurality of gradation data has dot ejection data and micro-vibration data, and the ejection drive signal is a dot for ejecting a liquid droplet from a nozzle opening in one cycle. Is a periodic signal having a pulse pulse waveform for microvibration and a pulse waveform for microvibration that slightly vibrates the liquid in the nozzle opening portion without ejecting liquid droplets from the nozzle opening, and the drive pulse generation means is based on the ejection drive signal , When the selected gradation data is the dot ejection data, the dot pulse waveform is used as the drive pulse, and when the selected gradation data is the minute vibration data, the minute vibration pulse waveform is used as the drive pulse. The frequency corresponding to the appearance interval of any two adjacent pulse waveforms is adjusted to be different from the natural frequency of the head member or an integral multiple thereof. The liquid ejecting apparatus according to claim 3. 7. A head member having a nozzle opening, a pressure changing means for changing the pressure of the liquid at the nozzle opening portion, a drive pulse generating means for generating a drive pulse based on ejection data, and a drive pulse based on the drive pulse. A method of manufacturing a liquid ejecting apparatus comprising: a control main body that drives a pressure fluctuation means, comprising a step of calculating a natural frequency of a head member, and a driving frequency of the pressure fluctuation means by the driving pulse. And an adjusting step of adjusting the calculated natural frequency of the head member so as to be different from an integer multiple of the calculated natural frequency. 8. The method according to claim 7, wherein in the adjusting step, the driving frequency of the pressure fluctuation means by the driving pulse is set to 10.8 kHz or more. 9. The head member includes a plurality of nozzle openings forming two parallel nozzle rows, a plurality of pressure chambers communicating with each nozzle opening to form two pressure chamber rows, and the two pressures. A central rib portion that is interposed between the chamber rows and extends on the side opposite to the nozzle opening, and the calculating step includes a step of calculating a natural frequency of the central rib portion. 9. The method according to claim 7 or 8, wherein
The method described in. 10. A head member having a nozzle opening, a pressure changing means for changing the pressure of the liquid in the nozzle opening portion, a drive pulse generating means for generating a drive pulse based on ejection data, and a drive pulse based on the drive pulse. A method of manufacturing a liquid ejecting apparatus comprising: a control main body that drives a pressure fluctuation means, comprising: a measuring step of measuring a natural frequency of a head member; And an adjusting step of adjusting the measured natural frequency of the head member to be different from an integer multiple of the measured natural frequency. 11. The driving frequency of the pressure fluctuation means by the driving pulse is set to 10.8 kHz or more in the adjusting step.
The method described in 0. 12. The head member includes a plurality of nozzle openings forming two parallel nozzle rows, a plurality of pressure chambers communicating with each nozzle opening to form two pressure chamber rows, and the two pressures. And a central rib portion that is interposed between the chamber rows and extends on the side opposite to the nozzle opening, and the measuring step has a step of measuring a natural frequency of the central rib portion. 9. The method according to claim 9 or 1, wherein
The method described in 0.