JP2004345274A - Head drive device, drive method, drive program and drawing device, device, electronic apparatus - Google Patents

Abstract

An object of the present invention is to provide a driving apparatus and a driving method for a nozzle head which prevent self-discharge of a piezoelectric element of a nozzle head in which ink is not discharged for a long time and stabilize ink discharging accuracy. .
A first driving waveform for discharging a liquid material in a nozzle head driving device for discharging a liquid material from each nozzle by operating a pressure generating element provided corresponding to each of a plurality of nozzles. And a drive waveform generator for generating a second drive waveform W2 for finely vibrating the pressure generating element without discharging the liquid material, and pressure generation by selecting the first drive waveform W1 and / or the second drive waveform W2. And a driving waveform applying section for applying the driving waveform to the element.
[Selection diagram] Fig. 4

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a head driving device capable of discharging a liquid material from a nozzle and a driving method thereof.
[0002]
[Prior art]
The ink jet type drawing apparatus has an ink jet type nozzle head having a number of nozzles in a sub-scanning direction (vertical direction). The nozzle head is moved in a main scanning direction (horizontal direction) by a carriage mechanism. By performing a predetermined screen feed, a desired image pattern is obtained. Drawing apparatuses are widely used not only for printing characters, pictures and photographs, but also for industrial applications such as manufacturing color filters for color liquid crystal devices and color electroluminescence (EL) display devices.
A nozzle head driving method for discharging ink involves applying a sharply changing drive voltage to a piezo element (piezo element) provided in a nozzle hole to generate a shape change in the piezo element. There is a piezo drive system in which ink droplets are ejected from a nozzle hole onto a sheet by a change in the volume of an ink chamber caused by the above, and various types of recording are performed.
Since the piezo element has electrical characteristics of capacitance, once charged to a certain potential, it theoretically holds that potential and keeps the amount of displacement due to that voltage. However, in practice, the charge stored in the piezo element is discharged by self-discharge of the piezo element itself with the passage of time. For example, in the case of drawing a single-color image, the interval at which each nozzle ejects ink (liquid) is not constant. Some nozzles eject ink continuously, while other nozzles eject ink through a long blank portion. May be done. When a color image is expressed by the mixing ratio of the three primary colors, the ink ejection interval of each color nozzle is not uniform, and a nozzle of a certain color may have a long ejection suspension time until the next ejection.
As described above, when the ejection of the ink from the nozzle is stopped for a long time, the electric charge stored in the piezo element is discharged, and the piezo element cannot maintain the initial displacement. When the next ejection drive voltage is applied, the shape of the piezo element changes more than a predetermined value, so that not only the optimal ink cannot be ejected, but the ink ejection accuracy is disturbed, but also the piezo element or There is a problem that a piezo element driving circuit or the like may be broken.
Then, in order to solve such a problem, as disclosed in Japanese Patent Application Laid-Open No. 2002-144558, a voltage for maintaining a constant bias potential of the piezoelectric element in which the ink discharging operation is suspended is applied to the piezoelectric element. There is a technique of providing a non-ejection voltage applying device for applying.
[0003]
[Patent Document 1]
JP-A-2002-144558 (page 4, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, in the above-mentioned technology, a special device for applying a non-ejection voltage waveform by switching a switch is required to keep the bias voltage of the piezoelectric element of the non-ejection nozzle constant, which increases the cost and increases the existing cost. There is a problem that it cannot be applied to the device.
[0005]
The present invention has been made in view of such a problem, and keeps a bias potential of a piezoelectric element of a nozzle head constant, prevents self-discharge of a piezoelectric element in which ink is not ejected for a long time, and reduces ink discharge. It is an object of the present invention to provide a driving device and a driving method of a nozzle head capable of stabilizing the ejection accuracy of the nozzle head.
[0006]
[Means for Solving the Problems]
In the nozzle head driving device and driving method, the drawing apparatus, the device, and the electronic apparatus according to the present invention, the following means are employed in order to solve the above problems.
According to a first aspect of the present invention, a first drive for discharging a liquid material is provided in a nozzle head driving device for discharging a liquid material from each nozzle by operating a pressure generating element provided corresponding to each of a plurality of nozzles. A drive waveform generating unit for generating a second drive waveform for finely vibrating the pressure generating element without discharging the waveform and the liquid material, and selecting the first drive waveform and / or the second drive waveform and selecting the first drive waveform and / or the second drive waveform. And a driving waveform applying unit for applying the driving waveform. According to the present invention, even when the ejection of the ink from the nozzle is stopped for a long time, the second drive signal is applied to the pressure generating element to cause the pressure generating element to slightly vibrate, thereby causing self-discharge. Can be prevented.
[0007]
In the case where the second drive waveform is applied in a cycle shorter than the self-discharge time of the pressure generating element, the self-discharge is prevented beforehand by applying the second drive waveform before the pressure generating element self-discharges. Can be.
Further, in a configuration in which the cycle of application of the second drive waveform is changed in accordance with the characteristics of the pressure generating elements, even if the characteristics of the individual pressure generating elements are non-uniform, By adjusting the characteristics, a stable ejection operation can be ensured.
Further, when the pressure generating element is a piezo element, effective vibration can be generated by a weak signal, so that a discharge failure of the liquid material can be prevented.
[0008]
According to a second aspect of the present invention, in a method of driving a nozzle head for discharging a liquid material from each nozzle by operating a pressure generating element provided corresponding to each of a plurality of nozzles, a first driving method for discharging the liquid material is provided. A step of generating a second drive waveform for finely vibrating the pressure generating element without discharging the waveform and the liquid material, and a step of selecting and applying the first drive waveform and / or the second drive waveform to the pressure generating element And so on. According to the present invention, even when the ejection of the ink from the nozzle is stopped for a long time, the second drive signal is applied to the pressure generating element to cause the pressure generating element to slightly vibrate, thereby causing self-discharge. Can be prevented.
[0009]
According to a third aspect of the present invention, in a driving program for a nozzle head for discharging a liquid from each nozzle by operating a pressure generating element provided corresponding to each of a plurality of nozzles, a first drive for discharging the liquid is provided. A process of generating a second drive waveform for finely vibrating the pressure generating element without discharging the waveform and the liquid material, and a process of selecting the first drive waveform and / or the second drive waveform and applying the selected drive waveform to the pressure generating element And made a computer execute. According to the present invention, even when the ejection of the ink from the nozzle is stopped for a long time, the second drive signal is applied to the pressure generating element to cause the pressure generating element to slightly vibrate, thereby causing self-discharge. Can be prevented.
[0010]
According to a fourth aspect of the present invention, there is provided a drawing apparatus which draws a pattern by discharging a liquid material from a nozzle head to a predetermined position on a substrate, and includes the nozzle head driving device according to the first aspect of the present invention. According to the present invention, even in a nozzle having a long liquid material discharge interval, self-discharge of the pressure generating element does not occur, so that accurate and clear pattern drawing can be performed.
[0011]
In a fifth aspect, the device has a pattern drawn by the drawing apparatus according to the fourth aspect. According to the present invention, a high-performance device can be provided because it is manufactured by a drawing apparatus capable of performing a stable ejection operation.
[0012]
In a sixth aspect, an electronic apparatus includes the device according to the fifth aspect. According to the present invention, since a device manufactured under a stable ejection operation is mounted, a high-performance electronic device can be provided.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an ink jet type drawing apparatus S of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing an ink jet type drawing apparatus S.
The ink jet type drawing apparatus (drawing apparatus) S includes a drawing controller (computer) 1 and a drawing engine 2, and discharges a liquid material onto a substrate (not shown). The drawing controller 1 includes an interface 3 (hereinafter, referred to as an I / F 3) for receiving image data and the like from a host computer (not shown), a RAM 4 for storing various data, a routine for various data processing, and the like. 5, a control unit 6 including a CPU, etc., an oscillation circuit 7, a drive signal generation unit 8 for generating a drive signal for the nozzle head 10, which will be described later, and a drawing engine for outputting various signals from these devices. And an I / F 9 for transmitting data to the I / F 2.
Hereinafter, the liquid ejected from the ink jet drawing apparatus S is referred to as ink.
[0014]
The I / F 3 receives, for example, any one of character code, graphic function, and image data or image data including a plurality of data from a host computer or the like. Further, the I / F 3 can output a busy signal (BUSY), an acknowledge signal (ACK), and the like to the host computer.
[0015]
The RAM 4 is used as a receiving buffer 4A, an intermediate buffer 4B, an output buffer 4C, a work memory (not shown), and the like. Image data from the host computer received by the I / F 3 is temporarily stored in the reception buffer 4A. The intermediate buffer 4B stores the intermediate code data converted into the intermediate code by the control unit 6. In the output buffer 4C, dot pattern data obtained by decoding color data described later is developed.
[0016]
The ROM 5 stores various control routines executed by the control unit 6, font data, graphic functions, various procedures, and the like.
[0017]
The control unit 6 reads out the image data in the reception buffer 4A, converts it into an intermediate code, and sends the intermediate code data to the intermediate buffer 4B for storage. Next, the control unit 6 analyzes the intermediate code data read from the intermediate buffer 4B, and develops the intermediate code data into dot pattern data with reference to font data and graphic functions in the ROM 5. The developed dot pattern data is stored in the output buffer 4C after necessary decoration processing is performed.
Further, the control unit 6 generates a change signal CH described later. The generation of the change signal CH is performed according to software. Then, based on the change signal CH, selection of a drive waveform W described later is controlled.
[0018]
The drive signal generation section (drive waveform generation section) 8 generates a plurality of drive waveforms W (W1, W2, etc.) for driving the piezoelectric vibrator 17 described later. Further, the plurality of drive waveforms W are combined to generate a drive signal COM having a potential difference sufficient to deform a pressure generating chamber of the nozzle head 10 described below and discharge ink. The drive waveform W is selected according to the drive program for each nozzle head 10 according to the drawing data.
[0019]
When the drawing controller 1 obtains dot pattern data corresponding to one line of the nozzle head 10, the dot pattern data for one line is serially transmitted to the nozzle head 10 via the I / F 9. When one line of dot pattern data is output from the output buffer 4C, the contents of the intermediate buffer 4B are deleted, and the next intermediate code conversion is performed. Here, the drawing data developed into the dot pattern data is composed of, for example, 6 bits (or 5 bits or 4 bits in other embodiments) as color data for each nozzle after translation.
[0020]
The drawing engine 2 includes a nozzle head 10, a substrate feeding unit 11, and a carriage unit 12. The substrate feeding unit 11 includes a substrate feeding motor, a substrate feeding roller, and the like, and sequentially feeds an image drawing medium such as a substrate to perform sub-scanning. The carriage section 12 includes a carriage on which the nozzle head 10 is mounted, a carriage motor for moving the carriage via a timing belt, and the like, and causes the nozzle head 10 to perform main scanning.
[0021]
The nozzle head (drive waveform applying unit) 10 has a large number of, for example, 64 nozzles 20 (20-1 to 20-N) in the sub-scanning direction, and discharges ink droplets from each nozzle at a predetermined timing. Things. The drawing data SI developed into the dot pattern data is serially transmitted from the I / F 9 to the shift register 13 in synchronization with the clock signal CK from the oscillation circuit 7. This serially transferred drawing data SI is temporarily latched by the latch circuit 14. The latched drawing data SI is boosted by the logic level shifter 15 as a voltage amplifier to a voltage that can drive the switch circuit 16, for example, a predetermined voltage value of about several tens of volts. The drawing data SI boosted to a predetermined voltage value is given to the switch circuit 16. The drive signal COM from the drive signal generator 8 is applied to the input side of the switch circuit 16, and the piezoelectric vibrator (pressure generating element) 17 is connected to the output side of the switch circuit 16.
[0022]
The drawing data SI controls the operation of the switch circuit 16. For example, while the drawing data SI applied to the switch circuit 16 is “1”, the drive signal COM is applied to the piezoelectric vibrator 17, and the piezoelectric vibrator 17 expands and contracts according to the drive signal COM. On the other hand, while the drawing data SI applied to the switch circuit 16 is “0”, the supply of the drive signal COM to the piezoelectric vibrator 17 is cut off.
[0023]
FIG. 2 is a block diagram illustrating the function of the nozzle head 10. The shift register circuit 13, the latch circuit 14, the logic level shifter 15, the switch circuit 16, and the piezoelectric vibrator 17 shown in FIG. 1 are elements 13-1 to 13 corresponding to the nozzles 20-1 to 20-N of the nozzle head 10, respectively. -N, 14-1 to 14-N, 15-1 to 15-N, 16-1 to 16-N, 17-1 to 17-N. The drawing data is composed of a total of 6-bit data from the most significant bit 5 to the least significant bit 0 for each nozzle 20, such as (100100) and (001001). Then, the bit data of each digit for all the nozzles 20-1 to 20-N is input to the shift registers 13-1 to 13-N within one image cycle.
[0024]
The drawing data SI is composed of a total of 6-bit data from the most significant bit 5 to the least significant bit 0 for each nozzle 20, such as (100100) and (001001). Bit data of each digit of -1 to 20-N is input to the shift registers 13-1 to 13-N within one image cycle. That is, after the data of the most significant bit 5 of all the nozzles 20-1 to 20-N is serially transferred to the shift registers 13-1 to 13-N, the bits of all the nozzles 20-1 to 20-N are transferred. 5 is latched by the latch elements 14-1 to 14-N. With this latch, the data of bit 4 for all the nozzles 20-1 to 20-N is transferred to the shift registers 13-1 to 13-N. Similarly, bit 3 data, bit 2 data, bit 1 data, and bit 0 data for all the nozzles 20-1 to 20-N are sequentially serially transferred.
[0025]
For example, when the bit data applied to each of the switch elements 16-1 to 16-N is “1”, the drive signal COM is directly applied to the piezoelectric vibrators 17-1 to 17-N, -1 to 17-N are displaced according to the signal waveform of the drive signal COM. On the other hand, when the bit data applied to each of the switch elements 16-1 to 16-N is “0”, the drive signal to each of the piezoelectric vibrators 17-1 to 17-N is cut off, and the respective piezoelectric vibrators 17-1 to 17-N are cut off. １７17-N hold the previous charge.
[0026]
On the other hand, when the change signal CH is input to the logic level shifter elements 15-1 to 15-N, bit data “1” is added to each of the switch elements 16-1 to 16-N, and the piezoelectric vibrator 17- It is set so that the second drive waveform W2 is directly applied to 1 to 17-N.
[0027]
FIG. 3 is a diagram illustrating an example of the mechanical structure of the nozzle 20. The substrate unit 21 is configured by sandwiching a flow path forming plate 24 between a nozzle plate 22 having a nozzle hole 22A formed therein and a vibration plate 23 having an island portion 23A formed therein. In the flow path forming plate 24, an ink chamber 25, an ink supply port 26, and a pressure generating chamber 27 are formed.
An accommodation room 29 is formed in the base 28, and the piezoelectric vibrator 17 (more precisely, any one of the piezoelectric vibrators 17-1 to 17 -N) is mounted in the accommodation room 29. The piezoelectric vibrator 17 is fixed via the fixed substrate 30 so that the tip thereof abuts on the island portion 23A of the diaphragm 23. Here, the piezoelectric vibrator 17 uses, for example, a piezo element having a longitudinal vibration lateral effect, and contracts when charged, and expands when discharged. The charging and discharging of the piezoelectric vibrator 17 is performed via the lead wire 31.
[0028]
Note that the piezoelectric vibrator 17 is not limited to a piezo element having a longitudinal vibration lateral effect, but may be a flexural vibration type piezo element. Further, the piezoelectric vibrator 17 is not limited to a piezo element, and another element such as a magnetostrictive element may be used. Alternatively, the ink may be heated by a heat source such as a heater, and the pressure may be changed by bubbles generated by the heating. In short, any element may be used as long as it causes a pressure fluctuation in the pressure generating chamber 27 according to a signal given from the outside.
[0029]
When the piezoelectric vibrator 17 is charged, the piezoelectric vibrator 17 contracts, the pressure generating chamber 27 expands, the pressure in the pressure generating chamber 27 decreases, and ink flows from the ink chamber 25 into the pressure generating chamber 27. On the other hand, when the piezoelectric vibrator 17 is discharged, the piezoelectric vibrator 17 expands, the pressure generating chamber 27 contracts, the pressure in the pressure generating chamber 27 increases, and the ink in the pressure generating chamber 27 passes through the nozzle hole 22A. Discharged to the outside via
[0030]
Next, the drive signal COM used in the ink jet drawing apparatus S of the present invention will be described. The drive signal COM generated by the drive signal generator 8 is generated at an image cycle of, for example, 14.4 kHz. FIG. 4 is a diagram schematically illustrating a waveform of the drive signal COM generated by the drive signal generation unit 8.
FIG. 4A is a diagram illustrating a first drive waveform W1 generated by the drive signal generation unit 8. FIG. The voltage value of the first drive waveform W1 starts from the intermediate potential Vm and rises from the intermediate potential Vm by a predetermined voltage gradient θA to a maximum potential higher by h1 (P1), and this maximum potential is maintained for a predetermined time t1 ( P2). Next, the voltage value of the first drive waveform W1 drops from the maximum potential to the lowest potential lower by h2 from the intermediate potential Vm with a predetermined voltage gradient θB (P3).
When a potential change corresponding to a potential change from the maximum voltage to the minimum voltage (that is, h1 + h2) is applied to the piezoelectric vibrator 17, ink is ejected from the nozzle hole 22A. As described above, the maximum potential h1 of the first drive waveform W1 is set to a potential that does not cause ink to be ejected from the nozzle hole 22A, and the lowest potential h2 of the first drive waveform W1 is determined when a potential change of (h1 + h2) occurs. The potential is determined such that ink is ejected from 22A.
[0031]
Here, the time required for the voltage value of the first drive waveform W1 to decrease from the maximum potential to the minimum potential is set substantially equal to the natural oscillation period TA of the piezoelectric vibrator 17. Note that the lowest potential is preferably the same as the ground level (0 V) or a positive potential in order to prevent the polarization reversal of the piezoelectric vibrator 17.
[0032]
Then, the voltage value of the first drive waveform W1 rises to the intermediate potential Vm again (P5) after holding the lowest potential for a predetermined time t2 (P4). The first drive waveform W1 that has risen to the intermediate potential Vm is held (P6) for a predetermined time t3. Here, the time from the start of the voltage drop from the maximum potential to the end of the maintenance of the minimum potential is set to be substantially the same as the natural cycle (Helmholtz cycle) of the ink.
[0033]
In order to form a new drive waveform W, it is preferable that potentials at connection points of the respective waveform elements are equal to each other. Therefore, by equalizing the potentials at the connection points of the respective waveform elements, the respective waveform elements can be smoothly connected, and it is possible to prevent a situation in which a rush current flows through a transistor or the like constituting the switch means and damage occurs. be able to. Therefore, if the first drive waveform W1 is provided with a flat portion P2 that is held at the maximum potential for a time t1 and divided by the flat portion P2, it is convenient when joining with another waveform. Similarly, the first drive waveform W1 is provided with a flat portion P4 that is held at the lowest potential for the time t2, and division at this flat portion P4 is convenient when joining with another waveform. Further, it may be divided at the flat portion (P6) of the holding time t3 provided at the intermediate potential Vm portion and joined to a second drive waveform W2 described later.
[0034]
FIG. 4B is a diagram showing a waveform of the second drive waveform W2 generated by the drive signal generator 8. The voltage value of the second drive waveform W2 starts from the intermediate potential Vm, rises from the intermediate potential Vm by a predetermined voltage gradient θC to a potential higher by h3 (P7), and maintains this potential for a predetermined time (t4) ( P8). Next, the voltage value of the second drive waveform W2 decreases from the potential higher than the intermediate potential Vm by h3 to the intermediate potential Vm with a predetermined voltage gradient θD (P9), and is maintained at the intermediate potential Vm (P10). The potential higher than the intermediate potential Vm by h3 is set to a voltage that does not cause ink to be ejected from the nozzle holes even when applied to the piezoelectric vibrator 17. That is, even if the second drive waveform W2 is applied to the piezoelectric vibrator 17, no ink is ejected from the nozzle holes, but the self-discharge of the piezoelectric vibrator 17 can be prevented.
[0035]
Each of the drive waveforms W involved in the formation of a new drive waveform W among the drive waveforms W in the drive signal COM has a flat pulse portion for maintaining a common potential. A new driving waveform W is formed by selectively connecting waveform elements obtained by dividing the section in the pulse width direction. If each pulse is formed so as to have a pulse portion that maintains a common potential, the potential at the connection point (cut point) of each waveform element obtained by dividing the flat pulse portion of each pulse in the pulse width direction is At the same potential. Further, since the flat pulse portion is divided in the pulse width direction, it is possible to absorb and cope with a shift in the pulse division position due to a change in timing.
[0036]
By compositely combining the first drive waveform W1 and the second drive waveform W2 formed as described above, a drive signal COM for driving the nozzle head 10 is formed.
FIG. 4C is a diagram schematically illustrating the waveform of the drive signal COM1. As shown in FIG. 4C, a continuous first drive waveform W1 is applied from the left of the drawing. The second drive waveform W2 is applied between the first drive waveforms W1. Thus, the second drive waveform W2 is applied immediately after the application of the first drive waveform W1. Note that the second drive waveform W2 in the new drive signal COM1 is a drive waveform W as a “non-ejection signal” that does not eject ink, and applies a slight vibration to the piezoelectric vibrator 17 to prevent self-discharge. Things.
[0037]
The first drive waveform W1 is applied to the new drive signal COM1 because the drawing controller 1 issues a latch signal LAT for introducing the first drive waveform W1. Similarly, the second drive waveform W2 is applied to the new drive signal COM1 because the drawing controller 1 issues a change signal CH for introducing the second drive waveform W2.
Thus, after the application of the first drive waveform W1, the second drive waveform W2 is applied to prevent the piezoelectric vibrator 17 from self-discharging. Therefore, the time t4 during which the second drive waveform W2 is applied may be short. This is because the intermediate potential Vm may be applied to the piezoelectric vibrator 17 and the initial displacement may be maintained.
As described above, the drawing controller 1 selects one of the first drive waveform W1 and the second drive waveform W2 to synthesize a new drive signal COM1. The first drive waveform W1 is appropriately selected and changed according to the image.
[0038]
FIG. 5 is a diagram schematically showing the waveform of another drive signal COM2. As for the drive signal COM2, the first drive waveform W1 is applied twice consecutively from the left side of the drawing, and then there is no signal for three times, and the first drive waveform W1 is applied again. The second drive waveform W2 is applied every other time. As described above, the second drive waveform W2 may be applied immediately after the first drive waveform W1 is applied, or the second drive waveform W2 may be applied while the first drive waveform W1 is not applied. .
As described above, even when the first drive waveform W1 is not applied, by applying the second drive waveform W2 at a cycle shorter than the self-discharge time of the pressure generating element 17, the piezoelectric element as indicated by the broken line in FIG. Self-discharge of the vibrator 17 can be prevented.
[0039]
FIG. 6 is a diagram showing the operation of the ink jet type drawing apparatus S according to the present invention. As described above, first, the drive waveforms W1 and W2 are generated in the drive signal generator 8 (S1). Then, in step 2, when the image data SI is input, a drive signal COM is generated (S3). On the other hand, the control unit 6 generates the latch signal LAT (S4).
Next, in step 5, it is determined whether or not to apply the first drive waveform W1, and if it is determined that the first drive waveform W1 is applied, the first drive waveform W1 is applied to the piezoelectric vibrator 17 (S6). Thereby, the liquid material is discharged from the nozzle 20.
Then, after the first drive waveform W1 is applied, or when it is determined that the application is not necessary, the change signal CH is output (S7).
Then, in step 8, it is determined whether or not to apply the second drive waveform W2. If it is determined that the second drive waveform W2 is to be applied, the second drive waveform W2 is applied to the piezoelectric vibrator 17 (S9). As a result, the piezoelectric vibrator 17 is slightly vibrated to prevent self-discharge.
Finally, it is determined whether or not the ejection of the liquid material is completed (S10). If the ejection (drawing) work is to be continued, the process returns to step 2. In the other case, the discharge operation is completed. In this way, a series of discharge operations is completed.
Even when the ejection of ink from a certain nozzle 20 is stopped, a driving waveform for finely oscillating the piezoelectric vibrator 17 is applied during that time, so that self-discharge of the piezoelectric vibrator 17 is prevented, and Even in the nozzle 20 where the ink discharge is interrupted for a long time, it is possible to always achieve smooth ink discharge.
In addition, since no special device is required, the cost can be reduced and the present invention can be applied to an existing device.
Even when the ejection of the ink from a certain nozzle 20 is stopped, it is possible to prevent the ink from becoming difficult to be ejected due to the increase in the viscosity of the ink due to the application of the micro-vibration during that time. The effect that discharge can be achieved can also be obtained.
[0040]
According to the drawing device employing the driving device and the driving method of the nozzle head 10 of the present invention, it is possible to maintain the ink ejection accuracy with high accuracy, and it is also possible to use ink with a high drying property, The present invention can be used for various industrial drawing apparatuses for manufacturing color filters for liquid crystal panels and electroluminescent display panels.
In the above-described embodiment, the ink may be a liquid material, and is not limited to a colored material. For example, a transparent material may be used. As another liquid material, there is a liquid material containing conductive fine particles. Examples of the conductive fine particles include metal fine particles containing any of gold, silver, copper, palladium, and nickel, as well as conductive polymer and superconductor fine particles.
[0041]
According to the driving device and the driving method of the nozzle head 10 of the present invention, the intermediate potential Vm is applied to the piezoelectric vibrator at a predetermined timing other than the time of the ink discharging operation. Thus, a stable ejection operation can be performed. Then, even if a low-boiling solvent having a boiling point of 250 ° C. or less is used for the ink, the meniscus of the ink in the nozzle is finely vibrated at a predetermined timing other than the time of the ink ejection operation. Therefore, a stable ejection operation can be performed. The use of a low-boiling solvent makes it possible to reduce the temperature after the drawing step, for example, in the baking step or the drying step, or to shorten the time. Can be suppressed. The low-boiling solvent referred to herein is, for example, a solvent having a boiling point of 250 ° C. or less, butyl carbitol acetate (boiling point: 246 ° C.), n-methyl-2-pyrrolidone (boiling point: 204 ° C.), 3-methoxypropionsan (Boiling point 150 ° C.).
[0042]
As described above, a metal wiring pattern, a circuit board including the same, or a device DS such as a liquid crystal display device or an organic EL display device can be obtained by the inkjet drawing apparatus S employing the driving apparatus and driving method of the nozzle head 10 of the present invention. Can be manufactured.
Further, it is possible to manufacture an electronic apparatus EQ equipped with these various devices DS. FIG. 7 is a diagram illustrating an example of an electronic apparatus EQ including the organic EL display device (device DS).
FIG. 7A is a perspective view illustrating an example of a mobile phone. In FIG. 7A, a mobile phone 1000 (electronic device EQ) includes a display unit 1001 using an organic EL display device (device DS).
FIG. 7B is a perspective view illustrating an example of a wristwatch-type electronic device. In FIG. 7B, a wristwatch 1100 (electronic device EQ) includes a display unit 1101 using the above-described organic EL display device (device DS).
FIG. 7C is a perspective view showing an example of a portable information processing device such as a word processor or a personal computer. 7C, the information processing apparatus 1200 (electronic device EQ) includes an input unit 1202 such as a keyboard, an information processing apparatus main body 1204, and a display unit 1206 using the above-described organic EL display device (device DS).
[Brief description of the drawings]
FIG. 1 is a conceptual diagram illustrating an ink jet drawing apparatus.
FIG. 2 is a block diagram illustrating functions of a nozzle head.
FIG. 3 is a diagram illustrating an example of a mechanical structure of a nozzle.
FIG. 4 is a diagram schematically showing a waveform of a drive signal.
FIG. 5 is a diagram schematically showing waveforms of other drive signals.
FIG. 6 is a diagram showing an operation of the ink jet type drawing apparatus.
FIG. 7 is a diagram illustrating an example of an electronic apparatus including a device.
[Explanation of symbols]
S Inkjet drawing apparatus (drawing apparatus) 1 Drawing controller (computer) 8 Drive signal generation section (Drive waveform generation section) 10 Nozzle head (Drive waveform application section) 17 Piezoelectric vibrator (Pressure generation element) 20 Nozzle W1 First drive Waveform W2 First drive waveform DS device EQ Electronic equipment

Claims (9)

In a nozzle head driving device for operating a pressure generating element provided corresponding to each of a plurality of nozzles and discharging a liquid material from each of the nozzles,
A drive waveform generator for generating a first drive waveform for discharging the liquid material and a second drive waveform for finely vibrating the pressure generating element without discharging the liquid material;
A driving waveform applying unit that selects the first driving waveform and / or the second driving waveform and applies the selected driving waveform to the pressure generating element. 2. The nozzle head driving device according to claim 1, wherein the second driving waveform is applied in a cycle shorter than a self-discharge time of the pressure generating element. 3. 3. The nozzle head driving device according to claim 1, wherein the application period of the second driving waveform is configured to be changed according to characteristics of the pressure generating element. 4. 4. The nozzle head driving device according to claim 1, wherein the pressure generating element is a piezo element. 5. In a method of driving a nozzle head for discharging a liquid material from each nozzle by operating a pressure generating element provided corresponding to each of a plurality of nozzles,
Generating a first drive waveform for discharging the liquid material and a second drive waveform for finely vibrating the pressure generating element without discharging the liquid material;
Selecting the first drive waveform and / or the second drive waveform and applying the selected drive waveform to the pressure generating element. A driving program for a nozzle head for operating a pressure generating element provided corresponding to each of a plurality of nozzles to discharge a liquid material from each of the nozzles,
Processing for generating a first drive waveform for discharging the liquid material and a second drive waveform for finely vibrating the pressure generating element without discharging the liquid material;
A program for selecting a first drive waveform and / or a second drive waveform and applying the selected drive waveform to the pressure generating element, causing a computer to execute the process. A drawing apparatus for drawing a pattern by discharging a liquid material from a nozzle head to a predetermined position on a substrate,
A drawing apparatus, comprising: the nozzle head driving device according to claim 1. A device having a pattern drawn by the drawing apparatus according to claim 7. An electronic apparatus comprising the device according to claim 8.

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