JP2003011352A - Actuator and recording medium storing driving program thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator in which the yield can be enhanced furthermore. SOLUTION: The driving signal of an ink jet recorder, an example of actuator, includes an ejection element 18 varying from an expansion potential VPS to a contraction potential VLS and contracting a pressure chamber in an expanded state to eject an ink drop, a second hold element 19 for holding the pressure chamber in a contracted state by keeping the contraction potential, and a damping element 20 varying from the contraction potential to an intermediate potential Vm and resetting the pressure chamber held in a contracted state by the second hold element to a normal state wherein the sum of the applying time pwd1 of the ejection element and the applying time pwh2 of the second hold element is equalized to the eigen frequency period Tc of the cavity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator device driven by a drive signal and an ink jet recording device represented by an ink jet printer, and a recording medium storing a program for driving them.

[0002]

2. Description of the Related Art An actuator device driven by using a drive signal is applied to various purposes. For example, in an ink jet recording head used in an ink jet recording apparatus such as an ink jet printer which is one form of an actuator device that is driven by using a drive signal, for example, a cavity (pressure chamber) is expanded / deformed by deformation of a piezoelectric vibrator.
It is known that the ink is ejected from the nozzle opening by contracting and expanding / contracting the cavity.

This type of recording head has a resolution of, for example, 7
Since it is extremely high at 20 dpi or 1440 dpi, very high processing accuracy in the unit of μm is required.

In this recording head, the deviation from the reference length of the free end portion of the piezoelectric vibrator due to mounting error,
Due to the processing accuracy of the piezoelectric vibrator and the cavity, the ejection characteristics of the ink droplets vary among the recording heads. Therefore, the optimum driving voltage is set for each recording head to correct the variation and uniform the ejection characteristics of the ink droplets. As a result, the quality of the recording head is stabilized and the yield is improved.

Further, as a drive signal generating device for driving an ink jet head which is one form of an actuator, a drive signal capable of programmatically generating a drive signal having a different drive signal according to environmental temperature can be used to correct a variation for each print head. The signal generator is Japanese Patent No. 2940.
No. 542.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object thereof is to provide an actuator device capable of driving an actuator using various drive signals with a suitable drive signal. To do.

It is another object of the present invention to provide an actuator device having high flexibility, which allows flexible setting of a drive signal even when the characteristics of the actuator device vary.

Further, the present invention is characterized in that the production yield of the ink jet recording apparatus, which is possessed by the ink jet recording apparatus which requires accurate and precise driving of the actuator, is improved.

[0009]

In order to solve such problems, the ink jet recording head of the present invention is
An actuator device having an actuator operable by a drive signal, wherein specific information of a constituent element of the actuator device is assigned to any one or a plurality of elements of the drive signal, and the specific information is stored. An identification information storage unit is provided, a drive signal generation unit forms the drive signal in a programmable manner, further refers to the identification information stored in the identification information storage unit, and drives including an element defined by the identification information. It is characterized by being driven by a signal.

Further, the actuator device is driven by a drive signal generated by assigning unique information, which is a unique value of the recording head, to any one or a plurality of elements of the drive signal. It is characterized by

Further, the characteristic information is a characteristic vibration period of a component constituting the actuator device.

Further, the characteristic information is a characteristic vibration period of a component forming the actuator.

Further, the characteristic information is a characteristic vibration period of the actuator.

Further, the characteristic information is information including information corresponding to the harmonics or sub-harmonics of the characteristic vibration period according to any one of claims 15 to 17.

Furthermore, a computer-readable recording medium, which is realized by a computer system including at least one computer and records a program for driving the actuator device according to claim 13 in the computer system, also protects the present application. Be the target.

Also included is an instruction for controlling a second program operating on a computer system including at least one computer, which is executed by the computer system to control the second program, A computer-readable recording medium in which a program for driving the actuator according to claim 13 is recorded in the computer system is also a protection target of the present application.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. An embodiment of the present invention will be described by taking an inkjet printer (hereinafter referred to as a printer), which is a typical inkjet recording device, as an example. As shown in FIG. 1A, the printer is roughly composed of a printer controller 1 and a print engine 2.

The printer controller 1 includes an external interface 3 (hereinafter referred to as an external I / F 3), a RAM 4 for temporarily storing various data, a control ROM 5 for storing control programs and the like, a CPU and the like. The control unit 6, the oscillation circuit 7 that generates a clock signal, the drive signal generation circuit 9 that generates a drive signal (COM) to be supplied to the recording head 8, and the development based on the drive signal and print data. And an internal interface 10 (hereinafter, referred to as an internal I / F 10) for supplying the dot pattern data (bitmap data) and the like to the print engine 2.

The external I / F 3 receives print data including, for example, a character code, a graphic function, image data, etc. from a host computer (not shown) or the like. Further, a busy signal (BUSY) and an acknowledge signal (ACK) are output to the host computer or the like through this external I / F 3.

The RAM 4 functions as a reception buffer 4A, an intermediate buffer 4B, an output buffer 4C, and a work memory (not shown). The reception buffer 4A temporarily stores the print data received via the external I / F 3, the intermediate buffer 4B stores the intermediate code data converted by the control unit 6, and the output buffer 4C stores the dot pattern data. Remember. The dot pattern data is composed of print data obtained by decoding (translating) the gradation data.

Further, the control ROM 5 stores font data, graphic functions, etc. in addition to a control program (control routine) for performing various data processing.

In addition to performing various controls, the control unit 6 reads the print data in the reception buffer 4A and stores the intermediate code data obtained by converting the print data in the intermediate buffer 4B. Further, the intermediate code data read from the intermediate buffer 4B is analyzed, and it is developed into dot pattern data with reference to the font data and graphic function stored in the control ROM 5. Then, the control unit 6 stores the dot pattern data in the output buffer 4C after performing necessary decoration processing.

If dot pattern data for one line which can be printed by one main scan of the print head 8 is obtained, this dot pattern data for one line is output from the output buffer 4C to the internal I / F 10. Are sequentially output to the recording head 8. When one line of dot pattern data is output from the output buffer 4C, the expanded intermediate code data is erased from the intermediate buffer 4B, and expansion processing is performed on the next intermediate code data.

As shown in FIG. 1B, the drive signal generation circuit 9 stores a ROM 11 in which waveform pattern information and the like forming a drive signal are stored, and an ID number (described later) set for each recording head 8. EEPROM 12 and EEPROM
Based on the ID number stored in M12, the waveform pattern information stored in the ROM 11 is referred to, and the recording head 8
Signal generator 13 for generating a series of drive signals suitable for
It is configured to include and.

The drive signal (COM) generated by the drive signal generator 13 is, for example, as shown in FIG.
The expansion element 16 that increases the potential from m to the expansion potential VPS with a constant voltage gradient, the first hold element 17 that holds the expansion potential VPS, and the expansion potential VPS to the contraction potential VLS.
A discharge element 18 that lowers the potential with a constant voltage gradient to
A pulse signal 21 (21A, 21B) composed of a second hold element (contraction hold element) 19 that holds the contraction potential VLS and a damping element 20 that raises the potential from the contraction potential VLS to the intermediate potential Vm with a constant voltage gradient. , 21C) are connected in series to form a signal.

The ROM 11 functions as ejection time information storage means, contraction holding time information storage means, damping time information storage means, damping voltage information storage means, drive voltage information storage means, and waveform pattern information. As
Application time pwd1 of ejection element 18 (ejection application time information)
, The application time pwh2 of the second hold element 19 (contraction holding time information), the application time pwc2 of the damping element 20 (vibration damping time information), and the potential difference VcN from the contraction potential VLS to the intermediate potential Vm (damping voltage). Information) and drive voltage VHN
Information of items including (driving voltage information) is stored. Further, the information of each item is composed of a plurality of types of application time and a plurality of types of potential difference information, and each numerical information is held in a state of being associated with an ID number. That is, one piece of information is held with one ID number.

Further, the EEPROM 12 functions as the ejection time identification information storage means, the contraction retention time identification information storage means, the damping time identification information storage means, the damping voltage identification information storage means, and the driving voltage identification information storage means in the present invention. Then
An ID number for the ejection element 18 (ejection time identification information), an ID number for the second hold element 19 (contraction holding time identification information), an ID number for the vibration damping element 20 (vibration time identification information), For the ID number for the potential difference VcN (damping voltage identification information) and the ID number for the drive voltage VHN (drive voltage identification information), set values for each recording head 8 are stored.

The drive signal generating section 13 functions as drive signal generating means in the present invention, and is an EEPROM.
These IDs are referred to by referring to the ID numbers for the ejection element 18 and the second hold element 19 stored in the table 12.
Generate a drive signal defined by a number.

The information stored in the ROM 11 and the EEPROM 12 and the drive signal will be described later in detail.

The print engine 2 has a paper feed mechanism 23.
The carriage mechanism 24 and the recording head 8 are included.

As shown in FIG. 2, the paper feeding mechanism 23 is composed of a paper feeding motor 25, a paper feeding roller 26, etc., and a recording paper (a kind of recording medium) 27 is interlocked with the recording operation by the recording head 8. And send them out sequentially. That is, the paper feeding mechanism 23 moves the recording paper 27 in the recording paper feeding direction which is the sub-scanning direction.

The carriage mechanism 24 is mounted on the carriage 31 on which the recording head 8 and the ink cartridge 29 can be mounted and is movably attached to the guide member 30, and the drive pulley 32 and the driven pulley 33, and the carriage mechanism 24. A pulse motor 3 for rotating the drive pulley 32 and the timing belt 34 connected to the carriage 31.
5 and.

In the carriage mechanism 24, the operation of the pulse motor 35 causes the carriage 31 to reciprocate along the width direction of the recording paper 27. That is, the recording head 8 mounted on the carriage 31 is moved along the main scanning direction.

Next, the recording head 8 will be described. In the recording head 8 illustrated in FIG. 3, a comb-shaped piezoelectric vibrator 40 is inserted from one opening into a storage chamber 39 of a box-shaped case 38 made of plastic, for example, and a comb-shaped tip 40a is formed.
To the other opening, and the flow path unit 41 is joined to the surface (lower surface) of the case 38 on the opening side, and the comb tooth-shaped tips 40a are abutted and fixed to predetermined portions of the flow path unit 41, respectively. It is roughly configured.

In the piezoelectric vibrator 40, a plate-shaped vibrator plate in which the common internal electrodes 43 and the individual internal electrodes 44 are alternately laminated with the piezoelectric body 42 sandwiched therebetween is cut into a comb tooth shape corresponding to the dot formation density. The base end side portion is joined to the fixing member 45 so as to be in a cantilevered state.
Is joined to the wall of the storage chamber 39. Then, by applying a potential difference between the common internal electrode 43 and the individual internal electrode 44, the free end portion of each piezoelectric vibrator 40, that is, the portion protruding outward from the overlapping end with the fixing member 45, is formed in the stacking direction. Expands and contracts in the longitudinal direction of the oscillator, which is orthogonal to

The flow path unit 41 is constructed by laminating a nozzle plate 48 and an elastic plate 49 on both sides with a flow path forming plate 47 interposed therebetween.

The flow path forming plate 47 communicates with a plurality of nozzle openings 50 formed in the nozzle plate 48, and a plurality of cavities (pressure chambers) arranged in a row with pressure chamber partitions.
51 is a plate member in which an elongated common ink chamber 53 is formed in which a plurality of ink supply portions 52 that communicate with 51 and at least one end of each cavity 51 communicate with each other. In this embodiment, a long and narrow common ink chamber 53 is formed by etching a silicon wafer, and cavities 51 are formed along the longitudinal direction of the common ink chamber 53 in accordance with the pitch of the nozzle openings 50. A groove-shaped ink supply unit 52 is formed between the common ink chamber 53 and the common ink chamber 53. The ink supply unit 52 is connected to one end of the cavity 51, and the nozzle opening 50 is located near the end on the opposite side of the ink supply unit 52. Further, the common ink chamber 53 is a chamber for supplying the ink stored in the ink cartridge 29 to the cavity 51, and the ink supply pipe 54 is provided at substantially the center in the longitudinal direction.

The elastic plate 49 is laminated on the other surface of the flow path forming plate 47 opposite to the nozzle plate 48, and a polymer film such as PPS is laminated on the stainless plate 55 as the elastic film 56. It has a double structure. Then, the stainless plate 55 of the portion corresponding to the cavity 51
Is etched to form an island portion 57 for abutting and fixing the piezoelectric vibrator 40.

In the recording head 8 having the above structure, the island portion 57 is pressed toward the nozzle plate 48 by extending the piezoelectric oscillator 40 in the oscillator longitudinal direction, and the elastic film 56 around the island portion 57 is formed. It deforms and the cavity 51 contracts. When the piezoelectric oscillator 40 is contracted in the oscillator longitudinal direction, the elasticity of the elastic film 56 expands the cavity 51. Then, by controlling the expansion / contraction of the cavity 51, an ink droplet is ejected from the nozzle opening 50.

The vibration system of the recording head 8 can be represented by the equivalent circuit shown in FIG. In FIG. 4, the symbol M is the inertance [Kg / m ⁴ ] which is the mass of the medium per unit length, Ma is the inertance in the piezoelectric vibrator 40, Mn is the inertance in the nozzle opening 50, and Ms is the ink supply unit. The inertance at 52. The symbol R is the resistance [N · s / m ⁵ ] which is the internal loss of the medium, Rn is the resistance at the nozzle opening 50, and Rs is the ink supply part 52.
Resistance in. The symbol C is the compliance [m ⁵ / N] which is the volume change per unit pressure, Cc is the compliance in the cavity (pressure chamber) 51, Ca is the compliance in the piezoelectric vibrator 40, Cn is the compliance in the nozzle opening 50. is there. The symbol P is the pressure generated by the piezoelectric vibrator 40 over time, in other words, the voltage pulse applied to the piezoelectric vibrator 40 is converted into an equivalent pressure.

The equivalent circuit of the piezoelectric vibrator system is shown in FIG.
The piezoelectric vibrator 4 can be represented as shown in FIG.
It is known that the natural vibration period Ta of 0 can be calculated by the following equation (1). The natural vibration period Ta calculated based on the equation (1), that is, the theoretical value was 4 μs in the recording head 8 of the present embodiment.

Ta = 2π√ (Ma · Ca) (1) Similarly, an equivalent circuit relating to the ink in the cavity 51 can be expressed as shown in FIG. It is known that the natural vibration period Tc can be calculated by the following equation (2). The natural vibration period Tc calculated based on the equation (2), that is, the theoretical value, was 8.5 μs in the recording head 8 of this embodiment.

Tc = 2π√ [[(Mn × Ms) / (Mn + Ms)] × Cc] (2) Furthermore, an equivalent circuit related to the meniscus of the nozzle opening 50 is shown in FIG. 5C. It is known from the figure that the natural vibration period Tm of the meniscus can be calculated by the following equation (3). Here, the meniscus is
The free surface of the ink exposed at the nozzle opening 50.

Tm = 2π√ [(Mn + Ms) Cn] (3) Then, in the recording head 8 of the present embodiment, Ta <Tc <
The relationship of Tm is established, and the natural vibration period Tm of the meniscus is about 10 times the natural vibration period Tc of the cavity 51.

Next, the electrical structure of the recording head 8 and the control for ejecting ink droplets will be described.

This recording head 8 is, as shown in FIG.
Shift register 60, latch circuit 61, level shifter 6
2, the switch 63, the piezoelectric vibrator 40, and the like.
Further, as shown in FIG. 5, these shift registers 6
0, latch circuit 61, level shifter 62, switch 63
And the piezoelectric vibrator 40 respectively include shift register elements 60A to 60A provided for each nozzle opening 50 of the recording head 8.
60N, latch elements 61A to 61N, level shifter elements 62A to 62N, switch elements 63A to 63N, and piezoelectric vibrators 40A to 40N.

In order to eject ink droplets from the recording head 8, the control section 6 synchronizes with the clock signal (CK) from the oscillation circuit 7 as shown in FIG.
I) is serially transmitted from the output buffer 4C and sequentially set in the shift register elements 60A to 60N. The print data for all nozzle openings 50 is the shift register element 6
If it is set to 0A to 60N, the control unit 6 causes the latch circuit 61, that is, the latch element 61, at a predetermined timing.
A latch signal (LAT) is output to A to 61N. By this latch signal, the latch elements 61A to 61N latch the print data set in the shift register elements 60A to 60N. The latched print data is supplied to the level shifter 62 which is a voltage amplifier, that is, the level shifter elements 62A to 62N.

When the print data is, for example, "1", each of the level shifter elements 62A to 62N boosts the print data up to a voltage value that can drive the switch 63, for example, several tens of volts. Then, the boosted print data is applied to the switch 63, that is, the switch elements 63A to 63N, and the switch elements 63A to 63N are brought into a connected state by the print data. The print data is, for example, "0".
In the case of, the corresponding level shifter elements 62A to 62A
N does not boost. Then, each switch element 63A to
63N has a drive signal (CO
When M) is applied and the switch elements 63A to 63N are brought into a connected state, a drive signal is supplied to the piezoelectric vibrators 40A to 40N connected to the switch elements 63A to 63N.

As described above, the drive signal is supplied to the piezoelectric vibrator 40 corresponding to the nozzle opening 50 in which the print data "1" is set. Then, the piezoelectric vibrator 40 expands and contracts in the vibrator longitudinal direction in response to the drive signal, and expands and contracts the cavity 51. Ink drops are ejected from the nozzle openings 50 as the cavities 51 expand and contract.

On the other hand, since the drive signal is not supplied to the piezoelectric vibrator 40 corresponding to the nozzle opening 50 in which the print data "0" is set, the volume of the cavity 51 is maintained in a steady state and the ink droplet is not ejected. .

Therefore, the print data "1" is set for the nozzle openings 50 for recording dots, and the print data "0" is set for the nozzle openings 50 for not recording dots, whereby each nozzle opening 50 is set. It is possible to control whether or not ink droplets are ejected for each.

Next, the above-mentioned drive signal will be described in detail. As shown in FIGS. 7 and 8, the drive signals of the present embodiment are the first pulse 21A, the second pulse 21B, and the third pulse 21A.
The pulse 21C is composed of a series of connected signals. Then, these first pulse 21A and second pulse 2
By applying 1B and the third pulse 21C to the piezoelectric vibrator 40, ink droplets of the same weight are ejected from the nozzle opening 50 three times in succession to form normal dots on the recording paper 27.
Form on top.

These first pulse 21A and second pulse 2
Since 1B and the third pulse 21C have the same waveform, the first pulse 21A will be described here.

The first pulse 21A holds the expansion potential VPS and the expansion element 16 for expanding the potential of the cavity 51 (pressure chamber) in the normal state by increasing the potential from the intermediate potential Vm to the expansion potential VPS with a constant voltage gradient. And the first hold element 17 for maintaining the expanded state of the cavity 51, and the expansion potential V
The discharge element 18 that lowers the potential at a constant voltage gradient from PS to the contraction potential VLS to contract the expanded cavity 51 to eject ink droplets and the contraction potential VLS to maintain the contracted state of the cavity 51. The second hold element (contraction hold element) 19 and the potential increase from the contraction potential VLS to the intermediate potential Vm with a constant voltage gradient, and the cavity 51 kept in the contracted state by the second hold element 19 is expanded and restored to the normal state. It is composed of a damping element 20.

When the expansion element 16 is applied to the piezoelectric vibrator 40, the normal piezoelectric vibrator 40 contracts in the longitudinal direction of the vibrator to expand the volume of the cavity 51. When the application of the expansion element 16 is finished and the first hold element 17 is applied to the piezoelectric vibrator 40, the contracted state of the piezoelectric vibrator 40 is maintained, and accordingly, the expanded state of the cavity 51 is also maintained. When the ejection element 18 is applied to the piezoelectric vibrator 40 after the application of the first hold element 17 is completed, the piezoelectric vibrator 40 in the contracted state rapidly expands in the longitudinal direction of the vibrator and contracts the volume of the cavity 51. . With this contraction, the ink pressure in the cavity 51 rapidly increases, and the nozzle opening 5
Ink droplets are ejected from 0. After the application of the ejection element 18 is completed and the second hold element 19 is applied, the damping element 2
When 0 is applied, the piezoelectric vibrator 40 in the expanded state contracts in the vibrator longitudinal direction and becomes the normal length. Along with this, the cavity 51 that was in the contracted state expands and returns to the normal state. Due to the expansion and return of the cavity 51, the ink pressure in the cavity 51 is reduced, and the vibration of the meniscus, which tends to vibrate greatly by the application of the ejection element 18, is reduced.

In this embodiment, the application time pwd1 of the ejection element 18 and the application time p of the second hold element 19 are set.
The added value of wh2 is adjusted to the natural vibration period Tc of the cavity (pressure chamber) 51.

The application time pwd1 of the ejection element 18 and the application time pwc2 of the vibration damping element 20 are both the piezoelectric vibrator 4
It is adjusted to the natural vibration period Ta of 0.

Here, the application time pwd1 of the ejection element 18
The reason why the added value of the application time pwh2 of the second hold element 19 is adjusted to the natural vibration period Tc will be described.

The piezoelectric vibrator 40 contracted by the application of the expansion element 16 and the first hold element 17 expands by the application of the ejection element 18. The expansion of the piezoelectric vibrator 40 causes the expanded cavity 51 to contract rapidly, and the meniscus also vibrates greatly. At this time, the vibration of the meniscus is strongly influenced by the contraction of the cavity 51.
The vibration cycle is the natural vibration cycle Tc of the cavity 51.

With the start of application of the discharge element 18, large vibration due to the natural vibration period Tc starts, and the expansion element 16
And the cavity 5 is applied by the application of the first hold element 17.
The meniscus pulled in 1 moves in the ink ejection direction. Then, the meniscus vibrating in the natural vibration period Tc reverses its movement direction after a lapse of time Tc / 2 from the start of movement in the ink ejection direction, and moves in the pull-in direction. After that, after a lapse of time Tc, the movement direction is reversed again, and the meniscus tries to move in the ink ejection direction.

Here, the application time pwd1 of the ejection element 18
Since the added value of the application time pwh2 of the second hold element 19 is adjusted to the natural vibration period Tc, the damping element 20 is applied after the time Tc has elapsed from the start of application of the ejection element 18. Since the piezoelectric vibrator 40 contracts and the cavity 51 expands with the application of the vibration damping element 20, the cavity 5 expands.
A negative pressure is created inside 1 to reduce the moving force of the meniscus that is about to move in the ink ejection direction. Therefore, the vibration of the meniscus can be suppressed.

Thus, the application time pw of the ejection element 18
By adjusting the added value of d1 and the application time pwh2 of the second hold element 19 to the natural vibration period Tc, the vibration of the meniscus can be effectively suppressed.

Next, the application time pwd1 of the ejection element 18 and the application time pwc2 of the vibration damping element 20 are calculated as follows.
The reason for matching with the natural vibration period Ta will be described.

First, the application time pwd1 and the application time pw
When c2 is set to be shorter than the natural vibration period Ta, the piezoelectric vibrator 40 changes in voltage of the ejection element 18 and the vibration damping element 20.
The phenomenon that the expansion and contraction of can not catch up occurs. That is,
The expansion and contraction of the piezoelectric vibrator 40 does not follow the voltage changes of the ejection element 18 and the damping element 20. For this reason,
The expansion and contraction of the piezoelectric vibrator 40 becomes unstable, and the cavity 51
It becomes difficult to control the expansion and contraction of the. as a result,
Ink ejection becomes unstable.

On the other hand, the application time pwd1 is set to the natural vibration period T
If it is set to be longer than a, the flight speed of the ink droplets may decrease or the amount of the ink droplets may become smaller than the regular amount. Then, due to the decrease in the flight speed of the ink droplets, the landing position of the ink droplets deviates from the normal position, which causes the deterioration of the image quality of the recorded image. Further, even when the amount of ink droplets becomes small, the quality of the recorded image also deteriorates. Further, when the application time pwc2 is set to be longer than the natural vibration period Ta, the expansion speed of the cavity 51 becomes slow and the damping effect becomes weak. Further, since the time required for the pulse signal also becomes long, the time required for forming one dot becomes long accordingly, and the recording speed is lowered.

From the above, the application time pwd1 and the application time p
By adjusting wc2 to the natural vibration cycle Ta, the expansion and contraction control of the piezoelectric vibrator 40 can be reliably performed. As a result, the required flight speed of the ink droplet can be secured, and the recording speed can be maintained at a high speed.

By the way, since the piezoelectric vibrator 40, the flow path unit 41, etc. are minute parts in the unit of mm and are minutely processed in the unit of μm, variations in characteristics occur among the recording heads 8. .

For example, the length of the free end portion of the piezoelectric vibrator 40 projecting from the overlapping end of the fixing member 45 varies from recording head 8 to recording head 8 due to a very slight positional deviation at the time of joining. The vibration cycle Ta is different. Further, the natural vibration period Tc varies among the recording heads 8 due to the dimensional tolerance of the cavity 51 based on the processing accuracy.

In the present embodiment, such a recording head 8
The variation of each is represented by the drive voltage VHN (potential difference from the expansion potential VPS to the contraction potential VLS) in the drive signal, the application time pwd1 of the ejection element 18, the application time pwh2 of the second hold element 19, and the application time pwc2 of the damping element 20. ,
The correction is performed by changing the potential difference VcN from the contraction potential VLS to the intermediate potential Vm.

The variation correction will be described below.

FIG. 9 shows the ROM 11 of the drive signal generation circuit 9.
9A is a diagram illustrating a part of the waveform pattern information stored in FIG. 9A, and FIG. 9A illustrates an ID number (ejection time identification information) corresponding to the application time pwd1 (ejection application time information) of the ejection element 18. FIG. 9 (b) shows the second hold element 19
I corresponding to the application time pwh2 (contraction hold time information) of
It is a figure explaining D number (contraction holding time identification information).

First, referring to these figures, the discharge element 1
The correction of the application time pwd1 of 8 and the application time pwh2 of the second hold element 19 will be described.

Regarding the application time pwd1 of the discharge element 18,
In the present embodiment, 0.1 from 3.5 μs to 4.5 μs
It is configured so that it can be set in μs steps. An ID number “0” is given to the theoretical value of 4 μs, and an ID number “1” is given to the shortest application time of 3.5 μs. After that, I is applied in ascending order of application time.
D number is given and the longest application time is 4.5
An ID number “B” is given to μs.

Similarly, regarding the application time pwh2 of the second hold element 19, in the present embodiment, from 3.1 μs to 6.
It is configured so that it can be set in steps of 0.2 μs up to 1 μs. An ID number "0" is given to the theoretical value of 4.5 μs, which is the shortest application time.
The ID number “1” is given to 1 μs. After that, the ID numbers are given in ascending order of the application time, and the longest application time of 6.1 μs is given the ID number “10”.

As described above, in the present embodiment, the added value of the application time pwd1 of the ejection element 18 and the application time pwh2 of the second hold element 19 is adjusted to the natural vibration period Tc of the cavity 51. The application time pwd1 of 18 is adjusted to the natural vibration period Ta of the piezoelectric vibrator 40. The theoretical value of the natural vibration period Tc is 8.
It is 5 μs, and the theoretical value of the natural vibration period Ta is 4 μs.

Therefore, when the measured natural vibration cycle Ta and the measured natural vibration cycle Tc are the theoretical values of the recording head 8, the ID number corresponding to the first hold element 17 is "0", and the second hold element is The ID number corresponding to 19 is set to “0”, and these ID numbers are set to the drive signal generation circuit 9
EEPROM 12 (ejection time identification information storage means and contraction retention time identification information storage means). Then, the drive signal generation unit 13 (drive signal generation means) is EEPRO.
Referring to the ID number stored in M12, the application time pwd1 of the ejection element 18 is set to 4 μs, and the application time pwh2 of the second hold element 19 is set to 4.5 μs,
A drive signal (COM) is generated in which the added value of the application time pwd1 and the application time pwh2 is set to 8.5 μs which is the theoretical value of the natural vibration period Tc.

The natural vibration period Ta was actually measured by observing the vibration state of the piezoelectric vibrator 40 using a laser displacement meter. Further, the natural vibration period Ta can be measured by measuring the counter electromotive force generated when a voltage is applied to the piezoelectric vibrator 40. The actual vibration period Tc is measured by adding a sinusoidal input signal to the piezoelectric vibrator 40,
The behavior of the meniscus at the nozzle opening 50 at that time was observed by using a stroboscope that emits light in synchronization with the input. That is, the natural vibration period Tc was measured by applying an input signal while changing the frequency and confirming that the ink meniscus vibrates greatly at a specific frequency. It can also be measured by observing the residual vibration of the ink meniscus after ink ejection by normal driving.

On the other hand, the measured natural vibration period Ta is 4.2 μs which is deviated from the theoretical value, and the measured natural vibration period T is
When c is 8.5 μs which is the theoretical value, the ID number corresponding to the ejection element 18 is set to “8”. Also, the second
The ID number of the hold element 19 is the ID number “7” corresponding to the time 4.3 μs obtained by subtracting the measured value 4.2 μs of the natural vibration period Ta from the measured value 8.5 μs of the natural vibration period Tc. These ID numbers are stored in the EEPROM 12 of the drive signal generation circuit 9.

Then, the drive signal generator 13 outputs the EEPR
The ejection element 18 is referred to by referring to the ID number stored in the OM 12.
The application time pwd1 of 4.2 μs
A drive signal is generated with the application time pwh2 of the hold element 19 set to 4.3 μs.

Further, when the actually measured natural vibration period Ta is 3.5 μs, which is largely deviated from the theoretical value, and the actually measured natural vibration period Tc is also 9.5 μs, which is also out of the theoretical value, in the case of the recording head 8, The ID number corresponding to the ejection element 18 is "1", and the ID number of the second hold element 19 is "1".
By setting it to "0", the drive signal having the optimum waveform can be supplied to the recording head 8.

In the above example, the measured natural vibration period T
Both a and the measured natural vibration period Tc are within the range described in FIG. 9 (pwd = 3.5 μs to 4.5 μs, pwh2 =
Although the examples of 3.1 to 6.1) are shown, it is clear that the present invention can be realized by appropriately adjusting the table corresponding to FIG. 9 when the eigenvalue to be assigned deviates from this range. .

As described above, the added value of the application time pwd1 and the application time pwh2 is calculated as the natural vibration period T of the cavity 51.
By adjusting to c, even if the natural vibration cycle Tc varies for each recording head 8, an optimum drive signal can be given to the natural vibration cycle Tc, and the vibration of the meniscus can be effectively suppressed. Furthermore, the application time pw
By correcting d1 according to the natural vibration cycle Ta of the piezoelectric vibrator 40, the expansion and contraction control of the piezoelectric vibrator 40 can be reliably performed even if the natural vibration cycle Ta varies.

Therefore, even the recording head 8 which has been conventionally treated as a defective product can be mounted on the product as a non-defective product, so that the yield of the recording head 8 can be further improved and the recording head 8 can be further improved. It is possible to reduce the cost of the printer, and eventually the cost of the printer.

The above is the application time p of the ejection element 18.
Although the setting of wd1 and the application time pwh2 of the second hold element 19 has been described, other items, that is, the drive voltage VHN in the drive signal and the application time pwc of the damping element 20.
2. The potential difference VcN from the contraction potential to the intermediate potential can be similarly corrected.

For example, the application time pwc2 of the damping element 20
With respect to, the ID number (contraction holding time identification information) is set in the same manner as the application time pwd1 of the ejection element 18, and the application time pwc2 is adjusted to the natural vibration period Ta of the piezoelectric vibrator 40. Then, the application time p of the damping element 20
By adjusting wc2 to the natural vibration cycle Ta, even if the natural vibration cycle Ta varies for each recording head 8,
The expansion and contraction control of the piezoelectric vibrator 40 at the time of damping the meniscus can be reliably performed. As a result, the allowable range of the recording head 8 that can be mounted on the product as a non-defective product can be widened, and the yield of the recording head 8 can be further improved.

Regarding the drive voltage VHN, the drive signal (first pulse 21A, second pulse 21B, third pulse 21C) is applied to the piezoelectric vibrator 40 at a reference temperature (for example, 25 ° C.) while changing the drive voltage VHN. The weight of the ink droplet ejected by applying the drive signal is measured. Then, the voltage value at which the actually measured ink droplet amount matches the reference ink droplet amount (for example, 40 ng) is set by the ID number (driving voltage identification information).

By thus configuring the drive voltage VHN so that it can be changed, the amount of ink droplets that fluctuate among the recording heads 8 can be made uniform.

Potential difference VcN from contraction potential to intermediate potential
In this embodiment, the voltage value of a predetermined ratio of the drive voltage VHN is set as the potential difference VcN based on the drive voltage VHN. Therefore, the information of the potential difference VcN (damping voltage information) is a ratio to the drive voltage VHN. For example, the theoretical value is 25% of the driving voltage (that is, V
cN = “25”) and set the ID to “25”.
The number "0" is given. Then, the ratio to the drive voltage VHN is stored in the ROM 11 in 1% steps so that it can be changed from 15% to 50%, for example, and a different ID number is assigned to each ratio.

Then, the ink drop is ejected while changing the potential difference VcN, and the residual vibration of the ink meniscus after the ink ejection is observed to observe the damping state of the meniscus. Then, the potential difference VcN having the most damping effect,
That is, the ID number (damping voltage identification information) of the potential difference VcN having a high damping effect is stored in the EEPROM 12.

Thus, if the potential difference VcN from the contraction potential to the intermediate potential (potential difference from the application start potential to the application end potential of the damping element 20) can be changed according to the attenuation of the meniscus vibration, The degree of expansion of the cavity 51 with the application of the element 20 can be adjusted. That is, by making the potential difference VcN larger than the reference potential difference VcN, the expansion degree of the cavity 51 can be made larger than the reference expansion rate.
Is smaller than the reference potential difference VcN, the cavity 5
The expansion degree of 1 can be made smaller than the reference expansion rate.

Therefore, immediately after the ink droplet is ejected, the potential difference VcN is used as the reference potential difference Vc for the recording head 8 whose meniscus vibrates more than the reference recording head 8.
It is set to be larger than N to increase the expansion rate of the cavity 51, and conversely, the potential difference VcN is set smaller than the reference potential difference VcN for the recording head 8 whose meniscus vibration is smaller than the reference recording head 8. By reducing the expansion rate of the cavity 51, the meniscus vibration state of each recording head 8 can be made uniform.

As a result, the recording head 8 having the characteristic that the meniscus vibrates greatly immediately after the ink droplets are ejected.
Even in this case, vibration of the meniscus can be suppressed in a short time. Therefore, even with such a recording head 8, the ejection operation based on the next drive pulse (for example, the second pulse 21B) can be stably performed, and the recording head 8 can be mounted on the product as a non-defective product. The range can be further expanded.

As described above, in the printer according to the present embodiment, regarding the drive signal (COM) applied to the recording head 8, the drive voltage VHN, the application time pwd1 of the ejection element 18, the application time pwh2 of the second hold element 19, and the vibration damping. Application time pwc2 of element 20, potential difference V from contraction potential to intermediate potential
Since each item of cN is configured to be changeable, it is possible to correct the ejection characteristics of the ink droplets that vary for each recording head 8, and to make the characteristics uniform.

Then, the application time pw of this discharge element 18
Since d1, the application time pwh2 of the second hold element 19, the application time pwc2 of the damping element 20, and the potential difference VcN from the contraction potential to the intermediate potential are also changeable, the conventional correction using only the drive voltage VHN The recording head 8 that has been treated as a defective product can also be mounted on the product as a good product, and the yield of the recording head 8 can be further improved.

Therefore, the cost of the recording head 8 is reduced,
As a result, the cost of the printer can be reduced.

Further, in this embodiment, the drive voltage VH
N, application time pwd1 of ejection element 18, application time pwh2 of second hold element 19, application time p of damping element 20
wc2, with respect to each item of the potential difference VcN from the contraction potential to the intermediate potential, a plurality of values (information) are stored in the ROM 11 in association with the ID number, and based on the ID number of each recording head 8 set in the EEPROM 12. Since the value suitable for the recording head 8 is selected, the optimum drive signal can be applied to the piezoelectric vibrator 40 only by storing the ID number in the EEPROM 12 during shipping adjustment of the printer. Therefore, the correction work for each recording head 8 can be easily performed.

The drive signal described above may be generated by a method using pulse width modulation, or the programmable drive signal generation method described in Japanese Patent No. 2940542 may be applied. Further, the drive signal generation method is not limited to these.

In this embodiment, the embodiment of the ink jet type recording apparatus is described as the actuator device, but the present invention is not limited to the above embodiment. For example, a drive signal in which the natural period of an energy generation unit that constitutes an actuator device is assigned as a part of a drive signal element is programmable, and the actuator is driven by using the drive signal to drive the actuator appropriately. You can Further, even if there is a variation in the natural period of the actuator, an actuator that is originally out of the standard can be used as a practical actuator device by applying the drive signal according to the present invention, and as a result, the yield of the actuator device is improved. be able to. Examples of actuators to which the present invention can be applied include piezoelectric fans and VTRs.
Head, ultrasonic motor, impact printer head,
Etc. are possible. Details are described in, for example, “Applications of Piezoelectric Ceramics” by Gakudonsha, so detailed description will be omitted here.

In the above description, the natural period dominant to the actuator driving is described, but the invention of the present application is not limited to this, and an integer fraction and an integer multiple of the natural frequency that produces the dominant natural period. It is obvious that the same effect can be obtained by setting each element or element group of the drive signal in (subharmonics and harmonics).

In the above-disclosed invention, a computer-readable recording medium recording a program for causing a computer system to generate a drive signal including each of the above elements is also a subject of protection of the present invention.

Further, when each of the above-mentioned elements is realized by a program such as an OS operating on a computer system, a recording medium recording a program including various instructions for controlling the program such as the OS is also a subject of protection of the present case. Become.

In this embodiment, the piezoelectric vibrator 40 is arranged so that the piezoelectric body 42 and the internal electrode 4 are arranged in the direction orthogonal to the expansion / contraction direction of the vibrator.
An example in which a comb-shaped vibrator of a so-called longitudinal vibration mode in which 3 and 44 are laminated is illustrated, but the present invention is not limited to this, and the piezoelectric body 42 and the internal electrodes 43 and 44 are arranged in the expansion and contraction direction of the vibrator. It can also be applied to the laminated piezoelectric vibrator 40 of so-called flexural vibration mode.

[0103]

As described above, the present invention has the following effects.

The present invention can provide an actuator device capable of driving an actuator using various drive signals with a suitable drive signal.

Further, it is possible to provide an actuator device having high flexibility in which the drive signal can be flexibly set even when the characteristics of the actuator device vary.

In addition, the manufacturing yield of various actuator devices can be improved.

[Brief description of drawings]

FIG. 1A is a block diagram illustrating a configuration of an inkjet printer, and FIG. 1B is a block diagram of a drive signal generation circuit.

FIG. 2 is a perspective view illustrating an internal mechanism of an inkjet printer.

FIG. 3 is a cross-sectional view illustrating the structure of a recording head.

FIG. 4 is an equivalent circuit for explaining a vibration system in a recording head.

5A and 5B are equivalent circuits of a recording head, where FIG. 5A is an equivalent circuit of a piezoelectric vibrator system, FIG. 5B is an equivalent circuit related to ink in a cavity, and FIG. 5C is an equivalent circuit related to a meniscus of a nozzle opening. Is.

FIG. 6 is a block diagram illustrating an electrical configuration of a recording head.

FIG. 7 is a diagram illustrating a drive signal in the recording head.

FIG. 8 is a diagram illustrating drive signals in a recording head.

FIG. 9 is a diagram illustrating a part of waveform pattern information,
(A) is a figure explaining the ID number corresponding to the application time of a discharge element, (b) is a figure explaining the ID number corresponding to the application time of a 2nd hold element.

[Explanation of symbols]

1 Printer controller 2 print engine 3 External interface 4 RAM 5 Control ROM 6 control unit 7 Oscillation circuit 8 recording head 9 Drive signal generation circuit 10 Internal interface 11 ROM of drive signal generation circuit 12 EEPROM of drive signal generation circuit 13 Drive signal generator 16 Expansion element 17 First hold element 18 Discharge element 19 Second hold element 20 damping element 21 pulse signal 23 Paper feed mechanism 24 Carriage mechanism 25 Paper feed motor 26 Paper feed roller 27 Recording paper 29 ink cartridges 30 Guide member 31 carriage 32 drive pulley 33 Driven pulley 34 Timing belt 35 pulse motor 38 cases 39 storage room 40 Piezoelectric vibrator 41 Channel unit 42 Piezoelectric body 43 Common internal electrode 44 individual internal electrodes 45 Fixing member 47 flow path forming plate 48 nozzle plate 49 elastic plate 50 nozzle opening 51 cavity 52 Ink supply section 53 common ink chamber 54 ink supply pipe 55 stainless steel plate 56 Elastic membrane 57 Island 60 shift register 61 Latch circuit 62 level shifter 63 switch 201 recording medium 202 reading device

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[Procedure amendment]

[Submission date] May 30, 2002 (2002.5.3)
0)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Actuator device and recording medium storing a program for driving them

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

In order to solve such problems, the ink jet recording head of the present invention is
An actuator device having an actuator operable by a drive signal composed of a plurality of elements, wherein each of the elements of the drive signal or a plurality of elements is assigned unique information of a constituent element of the actuator device, An identification information storage unit for storing the unique information is provided,
The drive signal generating unit is programmable to form the drive signal, further refers to the identification information stored in the identification information storage unit, and is driven by a drive signal including an element set by the identification information. And Further, the characteristic information is a characteristic vibration period of a component forming the actuator device. Further, the characteristic information is a characteristic vibration period of a component forming the actuator. Further, the characteristic information is a characteristic vibration cycle of the actuator. Also,
It is characterized in that the unique information is information including information corresponding to the harmonics or subharmonics of the natural vibration period according to any one of claims 2 to 4.
Further, a computer-readable recording medium that is realized by a computer system including at least one computer and records a program for driving the actuator device according to claim 1 in the computer system is also a protection target of the present application. . Also included are instructions for controlling a second program running on a computer system including at least one computer, executed by the computer system,
A computer-readable recording medium in which the program for controlling the second program to drive the actuator according to claim 1 is recorded in the computer system is also a subject of protection of the present application.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuichi Nakamura             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F term (reference) 2C056 EB07 EB59 EC07 EC42                 5C051 AA02 CA04 DA02 DB02 DB04                       DB06 DB07 DC02 DC07 DE02

Claims (8)

[Claims] 1. An actuator device having an actuator operable by a drive signal, wherein specific information of a component constituting the actuator device is assigned to any one or a plurality of elements of the drive signal, An identification information storage unit for storing unique information is provided, the drive signal generation unit forms the drive signal programmably, further refers to the identification information stored in the identification information storage unit, and is defined by the identification information. The actuator device is characterized in that it is driven by a drive signal including the above-mentioned elements. 2. The actuator device is driven by a drive signal generated by assigning unique information, which is a unique value of the recording head, to one or more of each element of the drive signal. The actuator device according to claim 1, wherein: 3. The actuator device according to claim 1, wherein the unique information is a natural vibration period of a component forming the actuator device. 4. The actuator device according to claim 1, wherein the unique information is a natural vibration period of a component forming the actuator. 5. The characteristic information according to claim 1, wherein the characteristic information is a characteristic vibration period of an actuator.
Actuator device according to. 6. An ink jet recording apparatus, wherein the unique information is information including information corresponding to the harmonics or subharmonics of the natural vibration period according to any one of claims 3 to 5. 7. A computer-readable recording medium, which is realized by a computer system including at least one computer and records a program for causing the computer system to drive the actuator device according to claim 1. 8. An instruction is included to control a second program running on a computer system including at least one computer, the instruction being executed by the computer system to control the second program, A computer-readable recording medium in which a program for driving the actuator according to claim 1 is recorded in the computer system.