JP2008168509A - Liquid droplet ejection head, ejection control method for liquid droplet ejector, and liquid droplet ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ejection control method for a liquid droplet ejection head and the like, which can make the amount of ejection of a liquid droplet and the like variable by a simple method. <P>SOLUTION: The liquid droplet ejection head comprises a nozzle 31, a channel which communicates with the nozzle 31, an individual electrode 12, and a diaphragm 22 which is supported as a part of the channel in such a manner as to face the individual electrode 12 at a predetermined distance. The ejection control method for the liquid droplet ejection head comprises; a step of displacing the diaphragm 22 to a position, where a predetermined interval is set between the diaphragm 22 and the individual electrode 12, by applying a first voltage between the diaphragm 22 and the individual electrode 12 so as to generate an electrostatic force; and a step of subsequently ejecting the liquid droplet by furthermore applying a driving voltage as a second voltage for ejecting the liquid droplet between the diaphragm 22 and the individual electrode 12, generating the electrostatic force between the diaphragm 22 and the individual electrode 12, and displacing the diaphragm 22 so as to pressurize a liquid in the channel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a discharge control method for a droplet discharge head or the like that is a microfabricated element. In particular, the present invention relates to a method for performing control so that the discharge amount and discharge speed of droplets can be changed.

  For example, micro electro mechanical systems (MEMS) that process silicon or the like to form minute elements or the like have made rapid progress. Examples of microfabricated elements formed by microfabrication technology include, for example, a droplet discharge head (inkjet head), a micropump, and an optical variable filter used in a recording (printing) apparatus such as a droplet discharge type printer. There are electrostatic actuators such as motors.

  Here, a droplet discharge head using an electrostatic actuator (electro-mechanical energy conversion element) will be described as an example of a microfabricated element. A droplet discharge type recording (printing) apparatus is used for printing in various fields regardless of whether it is for home use or industrial use. In the droplet discharge method, for example, a droplet discharge head having a plurality of nozzles is moved relative to an object, and droplets are discharged to a predetermined position of the object to record printing or the like. . This system is a microarray of biomolecules such as color filters for producing display devices using liquid crystals, display panels (OLEDs) using electroluminescent devices such as organic compounds, DNA, proteins, etc. Etc. are also used in the manufacture of

  The droplet discharge head includes a plurality of discharge chambers for storing liquid in a part of the flow path, and is a wall on at least one surface of the discharge chamber (here, a bottom wall, hereinafter referred to as a diaphragm). There is a method in which the pressure in the discharge chamber is increased by changing the shape and the droplets are discharged from each communicating nozzle. As the force (energy) for displacing the diaphragm, which is a movable part, for example, the diaphragm is a movable electrode, and static electricity is generated between the diaphragm and a fixed electrode (hereinafter referred to as an individual electrode) facing each other with a certain distance. A force (in particular, electrostatic attraction is used here, hereinafter referred to as electrostatic force) is generated. In the droplet discharge head, the electrostatic actuator is used as described above.

  Regarding the discharge operation of the droplet discharge head using the electrostatic actuator, for example, in the case of displacement driving, an electrostatic force is generated between the diaphragm and the individual electrode, and the diaphragm is attracted to the individual electrode. After that, if the electrostatic force is weakened or the generation is stopped, the restoring force (elastic force) that restores the shape of the discharge chamber (displaced diaphragm) to return to its original state becomes larger, so the diaphragm Is displaced to the original position. By repeating these, the diaphragm is driven (see, for example, Patent Document 1).

JP 2001-232790 A

  Here, if the displacement of the diaphragm is large, for example, the change of the liquid in the discharge chamber is large, and the restoring force is also large. An attempt has been made to change the discharge characteristics such as the discharge amount of droplets discharged from the nozzle by utilizing this. However, conventionally, since the discharge characteristics have been changed by changing the structure of the droplet discharge head, such as by forming individual electrodes in a stepped manner, man-hours and the like are required for manufacturing. Therefore, it was a factor to increase the cost.

  Accordingly, it is an object of the present invention to provide a discharge control method for a droplet discharge head or the like that can vary discharge characteristics such as a droplet discharge amount by a simpler method.

A droplet discharge head discharge control method according to the present invention includes a nozzle, a flow channel communicating with the nozzle, an individual electrode, and a diaphragm that is opposed to the individual electrode at a predetermined distance and is provided in a part of the flow channel. In the discharge control method of the droplet discharge head, the first voltage is applied between the diaphragm and the individual electrode to generate an electrostatic force, and the gap between the individual electrodes is at a predetermined distance. A step of displacing the diaphragm and a second voltage for discharging a droplet between the diaphragm and the individual electrode are further applied to generate an electrostatic force between the diaphragm and the individual electrode, thereby vibrating the diaphragm. And a step of displacing the plate to pressurize the liquid in the flow path and discharge the droplets.
According to the present invention, the first voltage is applied between the diaphragm and the individual electrode, the diaphragm is displaced in advance to a position having a predetermined interval, and then the second voltage is applied. Since the liquid in the flow path is pressurized and the liquid droplets are ejected from the nozzle, the applied voltage can be applied without complicating the structure of the liquid droplet ejection head, such as an individual electrode having a step structure. By simply performing control to change, it is possible to change the position of the diaphragm and perform discharge.

In addition, in the ejection control method of the droplet ejection head according to the present invention, the first voltage is applied in accordance with the interval between the individual electrode and the diaphragm that maximizes the droplet ejection speed by applying the second voltage. Then, the diaphragm is displaced.
According to the present invention, the diaphragm is displaced by applying the first voltage at a position where the discharge speed becomes maximum with respect to the second voltage. The discharged droplets can be made stable.

In the droplet discharge head ejection control method according to the present invention, the time for applying the first voltage is made longer than the time for applying the second voltage.
According to the present invention, the time for applying the first voltage is made longer than the time for applying the second voltage. A voltage of 2 can be applied, and stable ejection can be performed.

Further, according to the discharge control method of the droplet discharge head according to the present invention, the second voltage is applied between the vibration plate and the individual electrode by a voltage value arbitrarily selected from a plurality of voltage values. Is displaced, and droplets are discharged.
According to the present invention, the second voltage is applied at a voltage value selected from a plurality of voltage values to eject the droplets. Therefore, the ejection characteristics such as the droplet ejection amount are changed and used separately. Discharging can be performed. Thereby, for example, when printing or the like is performed by ejecting ink having different droplet ejection amounts for each landing position from the same nozzle, high-definition and high-quality printing can be performed.

In addition, the droplet ejection head ejection control method according to the present invention vibrates in advance so that the droplet ejection amount is maximized when the maximum voltage of the plurality of voltage values is applied as the second voltage. In the droplet discharge head in which the distance between the plate and the individual electrode is formed, when the maximum voltage is applied as the second voltage, the first voltage is set to 0 V, and the displacement of the diaphragm is set to zero.
According to the present invention, the interval between the diaphragm and the individual electrode is formed so that the droplet discharge head has the maximum droplet discharge amount when the maximum voltage is applied in advance, and the maximum voltage is applied. Since the first voltage is set to 0V so that the voltage is not substantially applied and the displacement of the diaphragm is set to 0, the displacement control of the diaphragm when the maximum voltage is applied is further simplified. Can do. Further, it is possible to easily set a reference for how much the diaphragm should be displaced with respect to each second voltage.

In addition, the discharge control method of the droplet discharge device according to the present invention controls the discharge of the droplet discharge device by applying the discharge control method of the droplet discharge head described above.
According to the present invention, since the ejection control method for the droplet ejection head described above is applied, ejection can be performed with different ejection characteristics for each droplet from the nozzles of the droplet ejection head. Accordingly, for example, when printing is performed by a droplet discharge device, high-definition and high-quality printing can be performed.

Further, a droplet discharge device according to the present invention performs discharge control by the above-described discharge control method of the droplet discharge head, and discharges droplets onto a discharge target.
According to the present invention, since the discharge control method of the droplet discharge head described above is applied, discharge is performed with different discharge characteristics for each landing position from the same nozzle. For example, when the discharge target is a printed matter such as paper In addition, it is possible to obtain a droplet discharge device that can perform high definition and high image quality printing.

Embodiment 1 FIG.
FIG. 1 is an exploded view of a droplet discharge head according to Embodiment 1 of the present invention. FIG. 1 shows a part of the droplet discharge head. In this embodiment, as a representative of a device using an electrostatic actuator driven by an electrostatic method, for example, a face eject type droplet discharge head used in a droplet discharge device such as a printer will be described. The droplet discharge head is a device in which a plurality of electrostatic actuators are integrated for the purpose of forming an image by discharging droplets, for example. In addition, in order to illustrate the constituent members and make it easy to see, the relationship between the sizes of the constituent members in the following drawings including FIG. 1 may be different from the actual one. Further, description will be made with the upper side of the figure as the upper side and the lower side as the lower side.

  As shown in FIG. 1, the droplet discharge head according to the present embodiment is configured by laminating three substrates of an electrode substrate 10, a cavity substrate 20, and a nozzle substrate 30 in order from the bottom. In the present embodiment, the electrode substrate 10 and the cavity substrate 20 are bonded by anodic bonding. The cavity substrate 20 and the nozzle substrate 30 are bonded using an adhesive such as an epoxy resin.

  The electrode substrate 10 is mainly made of a substrate such as a borosilicate heat-resistant hard glass having a thickness of about 1 mm. In the present embodiment, the glass substrate is used, but single crystal silicon may be used as the substrate, for example. On the surface of the electrode substrate 10, a plurality of recesses 11 having a depth of about 0.3 μm, for example, are formed in alignment with the recesses that become the discharge chambers 21 of the cavity substrate 20 described later. The individual electrodes 12 serving as fixed electrodes are provided inside the recess 11 (particularly at the bottom) so as to face each discharge chamber 21 (vibrating plate 22) of the cavity substrate 20, and the lead portion 13 and the terminal portion 14 are further provided. They are provided integrally (hereinafter, these are collectively described as individual electrodes 12 unless otherwise distinguished). Between the diaphragm 22 and the individual electrode 12, a certain gap (gap) that allows the diaphragm 22 to bend (displace) is formed by the recess 11. Here, the gap interval formed between the diaphragm 22 (insulating film 23) and the individual electrode 12 is referred to as a gap length. The individual electrode 12 is formed by depositing ITO with a thickness of 0.1 μm inside the recess 11 by, for example, sputtering. In addition, the electrode substrate 10 is provided with a through hole serving as a liquid supply port 15 serving as a flow path for taking in liquid supplied from an external tank (not shown).

The cavity substrate 20 is mainly made of, for example, a silicon single crystal substrate (hereinafter referred to as a silicon substrate) whose surface is (110) plane orientation. The cavity substrate 20 is formed with a recess that becomes a discharge chamber 21 for temporarily storing a liquid to be discharged (the bottom wall is a vibration plate 22 that becomes a movable electrode) and a recess that becomes a reservoir 24. Furthermore, a TEOS film (here, Tetraethyl orthosilicate Tetraethoxysilane: tetraethylorthosilicate (ethyl silicate) is used on the lower surface of the cavity substrate 20 (surface facing the electrode substrate 10) to electrically insulate the individual electrodes 12 from each other. The insulating film 23 made of a silicon oxide (SiO ₂ ) film formed by using as a source gas is formed to a thickness of 0.1 μm. Here, the insulating film 23 is formed of a TEOS film, but Al ₂ O ₃ (aluminum oxide (alumina)) or the like may be used, for example. Here, unless otherwise specified, the description will be made assuming that the diaphragm 22 and the insulating film 23 are integral. In addition, a recess is formed which becomes a reservoir (common liquid chamber) 24 for supplying a liquid to each discharge chamber 21. Furthermore, a common electrode terminal 27 is provided as a terminal for supplying electric charges from an external power supply means (not shown) to the cavity substrate 20 (the diaphragm 22).

  The nozzle substrate 30 is also mainly made of a silicon substrate, for example. A plurality of nozzles 31 are formed on the nozzle substrate 30. Each nozzle 31 discharges the liquid pressurized by the displacement of the diaphragm 22 to the outside as a droplet. In the present embodiment, the holes of the nozzle 31 are formed in a plurality of stages in order to improve the straightness of the discharged droplets. Further, a diaphragm 32 is further provided for buffering the pressure applied in the direction of the reservoir 24 as the diaphragm 22 is bent. Further, an orifice 33 serving as a groove for communicating the discharge chamber 21 and the reservoir 24 is provided.

  FIG. 2 is a cross-sectional view of the droplet discharge head. In FIG. 2, the discharge chamber 21 stores liquid to be discharged from the nozzle 31. By bending the diaphragm 22 which is the bottom wall of the discharge chamber 21, the pressure in the discharge chamber 21 is increased, and droplets are discharged from the nozzle 31. Here, a sealing material 25 is provided at the electrode outlet 26 in order to block and seal the gap from the outside air so that foreign matter, moisture (water vapor) and the like do not enter the gap.

  FIG. 3 is a diagram illustrating a configuration centering on the drive control circuit 40. Based on FIG. 3, a description will be given of means for performing control for discharging droplets from the droplet discharge head. The drive control circuit 40 includes a head control unit 41 configured around a CPU 42a. For example, a signal including print data is transmitted from the external device 50 such as a computer to the CPU 42a of the head controller 41 via the bus 51.

  The head controller 41 includes a ROM 43a, a RAM 43b, and a character generator 43c, and is connected to the CPU 42a via an internal bus 42b. The CPU 42a executes processing based on a control program stored in the ROM 43a, and generates an ejection control signal corresponding to the printing data. At that time, the storage area in the RAM 43b is used as a work area, and when printing characters or the like, processing based on character data stored in the character generator 43c is performed. The ejection control signal generated by the CPU 42a is transmitted to the logic gate array 45 via the internal bus 42b. Based on the ejection control signal, the logic gate array 45 generates a signal related to charge supply to each individual electrode 12 as described later. Further, a signal relating to charge supply to the cavity substrate 20 (the diaphragm 22) is generated from the COM generation circuit 46a as described later. The drive pulse generation circuit 46b generates a signal for synchronization. These signals are transmitted to the driver IC 48 via the connector 47 as signals indicating the voltage applied between the diaphragm 22 and the individual electrode 12.

  The driver IC 48 is electrically connected to the terminal portion 14 and the common electrode terminal 27 directly or via a wiring 49 such as an FPC (Flexible Print Circuit) or a wire. If the number of terminals of the driver IC 48 is not enough for the number of nozzles 31 of the droplet discharge head, the driver IC 48 may be composed of a plurality of driver ICs 48. The driver IC 48 is supplied with electric power from a power supply and power supply circuit 60 (hereinafter referred to as the power supply circuit 60), and supplies charges to the cavity substrate 20 (each diaphragm 22) and each individual electrode 12 based on the various signals described above. This is means for actually starting (charging), charge holding and discharging (these are charge supply control). In the present embodiment, charge supply control that changes the voltage between the diaphragm 22 and the individual electrode 12 can be performed on each individual electrode 12. Then, charge supply (voltage application) control between each diaphragm 22 corresponding to each nozzle 31 and the individual electrode 12 is performed. First, a first voltage (hereinafter referred to as a standby displacement voltage) is applied to each vibration. Displace the plate 22 to a predetermined gap length, and then apply a second voltage for ejecting droplets from the nozzle 31 (hereinafter referred to as drive voltage) to further displace the diaphragm 22 to eject droplets. Is to do.

  The driver IC 48 applies a predetermined voltage between the cavity substrate 20 and each individual electrode 12 based on the generation timing of each pulse or the like of the cavity substrate 20 (the diaphragm 22) and each individual electrode 12 (the potential difference is set). generate). As a voltage application method, for example, a positive or negative charge is supplied to one of the cavity substrate 20 (the diaphragm 22 side) or the individual electrode 12 side, and a state in which no charge is supplied to the other is created. A potential difference is generated and a voltage is applied.

  An electrostatic force is generated between the diaphragm 22 and the individual electrode 12 by applying a voltage, and the diaphragm 22 is drawn toward the individual electrode 12 and bends. For this reason, the volume of the discharge chamber 21 increases, but if this deflection is large, the amount of liquid in the discharge chamber 21 increases, and the restoring force when the diaphragm 22 tries to return to the original state increases. Pressure due to this restoring force is applied to the liquid, and the liquid is pushed out from the nozzle 31 and discharged as droplets. Recording such as printing is performed when the droplets land on a recording sheet to be recorded, for example.

  FIG. 4 is a diagram illustrating the relationship between the gap length and the droplet ejection characteristics. The droplet discharge characteristics in FIG. 4 basically represent the droplet discharge amount. The diaphragm 22 has a width of 100 μm, a thickness of 2 μm, and a length of 3 mm (3000 μm).

  For example, when the drive voltage is constant as shown in FIG. 4A, the relationship between the gap length and the droplet discharge characteristics is represented by a graph, and the droplet discharge amount peaks at a certain gap length. Draw a convex curve. Here, although the peak gap lengths do not always coincide with each other, the relationship between the gap length and the droplet discharge speed is considered to tend to draw a convex curve.

  Basically, if the droplet discharge amount is large (or if the droplet discharge speed is high), the discharged droplet continues to fly stably until landing. Therefore, in order to stabilize the ejected liquid droplets, a predetermined gap length at which the discharge characteristics reach a peak at a predetermined driving voltage may be used. For example, in FIG. 4, when the drive voltage is 35 V, the gap length at the peak of the ejection characteristics is 200 nm (0.2 μm). A driving voltage of a maximum of 35 V is applied from the driver IC 48 to the droplet discharge head of the present embodiment. In such a case, in order to obtain an optimum gap length, the droplet discharge head according to the present embodiment is designed so that the gap length is 200 nm (0.2 μm). Thereby, when the drive voltage is 35 V, ejection can be performed at the peak without performing displacement.

  Further, as shown in FIG. 4A, when the drive voltage is changed, the higher the drive voltage, the longer the gap length and the greater the amount of liquid droplet ejected. The curve shifts in the upper right direction of the graph (in contrast, the curve shifts in the lower left direction as the drive voltage decreases).

  FIG. 5 is a diagram showing an example of the relationship between the driving voltage at the peak, the gap length, and the droplet ejection characteristics. As shown in FIGS. 4 and 5, the droplet discharge amount (droplet discharge speed) can be changed by changing the drive voltage. Here, as shown in FIG. 4B, it is possible to eject droplets by changing only the drive voltage without changing the gap length, but the droplet ejection speed is greatly reduced. For this reason, for example, there is a high possibility that the liquid becomes thickened and cannot be ejected, for example, a variation in landing position on the paper surface becomes large. As described above, in order to change the droplet discharge amount in a stable state and discharge the droplet, it is desirable that the discharge characteristics reach a peak. Therefore, the driving (droplet discharging operation) may be performed by a combination of the driving voltage and the gap length at which the discharge characteristics reach a peak. For example, according to FIG. 5, the gap length is 200 nm (0.2 μm) when the driving voltage is 35 V, 170 nm (0.17 μm) when 30 V, and 140 nm (0.14 μm) when 25 V. To a combination.

  Therefore, in the present embodiment, a predetermined standby displacement voltage is applied to displace the diaphragm 22 in a stage before the displacement of the diaphragm 22 for discharging droplets, and a predetermined gap length ( (Interval). Then, in order to displace the diaphragm 22 that discharges the liquid droplets, a predetermined driving voltage is further applied between the diaphragm 22 and the individual electrode 12 to displace the diaphragm 22 from a predetermined gap length, The liquid is discharged from the nozzle 31 under pressure.

  FIG. 6 is a diagram showing a waveform example of a voltage (potential difference to be generated) applied between the diaphragm 22 and the individual electrode 12 by the drive control circuit 40 (driver IC 48) in a certain driving cycle and setting examples of each mode with respect to the waveform. It is. FIG. 6A shows the waveform of the applied voltage, and FIG. 6B shows three mode setting examples.

  In FIG. 6, a voltage V2 is a voltage applied to eject a droplet, and is a voltage corresponding to the drive voltage described above. In FIG. 6B, the value is set to 35V in mode 1, 30V in mode 2, and 25V in mode 3. The voltage V1 is a voltage corresponding to a standby displacement voltage that is applied in order to give a displacement for displacing the diaphragm 22 and making it stand by with a predetermined gap length. In FIG. 6B, since displacement is not required in mode 1 (the displacement is 0), the value is set to 0V, mode 2 is 5V, and mode 3 is 7V. Here, the voltage V1 (standby displacement voltage) in each mode varies depending on the gap length to be displaced, but a test is performed before a droplet discharge device having a droplet discharge head and a drive control circuit 40 is manufactured and shipped. Sometimes, for example, the drive control circuit 40 may perform the setting by measuring the relationship between the drive voltage and the displacement (deflection amount) of the diaphragm 22 at that time. Further, depending on the configuration of the drive control circuit 40 or the like mounted on the droplet discharge device, the gap length may be determined each time before the operation to set the voltage V1 corresponding to the droplet discharge device. Here, the gap length can be calculated by calculating the capacitance between the diaphragm 22 and the individual electrode 12.

  On the other hand, in each mode, the applied voltage is different, but the timing for changing the voltage is made the same. For example, in each mode of FIG. 6B, the time T1 for applying a voltage for waiting with a predetermined gap length is set to 2 μs. Further, the time T2 for applying the voltage (driving voltage) applied to eject the droplet is set to 30 μs. Furthermore, in the present embodiment, the voltage application is stopped and the discharge time T3 is set to 42 μs.

  Here, in FIG. 6, the interval between T1 and T2 is 28 μs. This is to secure time for attenuating and stopping the vibrations of the diaphragm 22 and the liquid generated by displacing the diaphragm 22 to obtain a predetermined gap length according to each mode. Therefore, for example, if the diaphragm 22 and the like can be stopped in a faster time, it is not necessary to limit the time to 28 μs. In FIG. 6, the interval between T2 and T3 is 12 μs, but this value is not limited. Basically, it is not intended to stabilize the diaphragm 22 and the liquid, so the time between T2 and T3 is shorter than the time between T1 and T2.

  As described above, based on the droplet discharge amount to be discharged from each nozzle of the droplet discharge head, a plurality of modes are selectively used, and the standby displacement voltage according to the drive voltage is applied to previously set the diaphragm 22 in advance. Displace it so that stable discharge is performed.

  As described above, according to the first embodiment, the vibration plate 22 and the vibration plate 22 are individually separated at the stage before the displacement of the vibration plate 22 for discharging droplets by the control of the drive control circuit 40 (IC driver 48). A predetermined standby displacement voltage is applied between the electrode 12 and the diaphragm 22 is displaced to have a predetermined gap length in advance, and then a predetermined driving voltage is applied to eject a droplet from the nozzle 31. Therefore, for example, even if the structure of the droplet discharge head is not complicated, such as an individual electrode having a step structure, the gap length can be increased only by changing the applied voltage (waveform). Can be changed. Then, the diaphragm 22 can be displaced from a predetermined gap length to pressurize the liquid and discharge the liquid droplets. Further, by changing the drive voltage, the droplet discharge amount can be changed according to the drive voltage. When discharging droplets, for example, a standby displacement voltage is applied so that the gap discharge amount or the droplet discharge speed reaches a peak at a predetermined drive voltage, and the diaphragm 22 is displaced. By doing so, the ejected droplets can be stabilized by a predetermined driving voltage. By stably ejecting the droplets, a large shift of the landing position does not occur, and high-definition and high-quality printing can be performed, for example, when printing is performed. Further, when manufacturing a droplet discharge head that performs control as in the present embodiment, the gap optimal for the drive voltage corresponding to the maximum droplet discharge amount (discharge speed) can be obtained without displacing the diaphragm 22. If the concave portion 11 is formed so as to be long, it is possible to stably discharge a maximum amount of liquid droplets without being displaced.

Embodiment 2. FIG.
In the above-described embodiment, the liquid droplet ejection head configured by stacking the three substrates of the electrode substrate 10, the cavity substrate 20, and the nozzle substrate 30 has been described. However, the configuration of the liquid droplet ejection head is not limited thereto. It is not something. For example, the present invention can also be applied to a droplet discharge head that includes a four-layer substrate in which a reservoir is formed on a substrate different from the discharge chamber.

Embodiment 3 FIG.
In the above-described embodiment, for example, as shown in FIG. 6A, the voltage applied as the standby displacement voltage is made constant between T1 and T2 so that the control can be easily performed. It is not limited to. For example, the voltage waveform may be such that a predetermined gap length can be obtained while suppressing vibration of the diaphragm 22 and liquid due to displacement.

  Further, after the discharge start time T3, the voltage may be kept at V1 without being lowered to 0V and maintained at the value of V1 until the next discharge operation. In this case, during discharge, voltage change and capacitance change in the actuator portion can be suppressed to a small value, and the current value flowing in the drive circuit such as the driver IC 48 can be suppressed.

Embodiment 4 FIG.
FIG. 7 is an external view of a droplet discharge apparatus (printer 100) using the droplet discharge head manufactured in the above-described embodiment. FIG. 8 is a diagram illustrating an example of main components of the droplet discharge device. 8 and 9 is intended for printing by a droplet discharge method (inkjet method). Further, it is a so-called serial type device. In FIG. 9, a drum 101 that supports a printing paper 110 that is a substrate to be printed and a droplet discharge head 102 that discharges ink to the printing paper 110 and performs recording are mainly configured. Although not shown, there is an ink supply means for supplying ink to the droplet discharge head 102. The print paper 110 is held by being pressed against the drum 101 by a paper press roller 103 provided parallel to the axial direction of the drum 101. A feed screw 104 is provided parallel to the axial direction of the drum 101, and the droplet discharge head 102 is held. As the feed screw 104 rotates, the droplet discharge head 102 moves in the axial direction of the drum 101.

  On the other hand, the drum 101 is rotationally driven by a motor 106 via a belt 105 or the like. The drive control circuit 40 drives the feed screw 104 and the motor 106 based on the printing data and the control signal. Although not shown here, as described in the first embodiment, COM and each SEG are output from the driver IC 48 to vibrate the diaphragm 22, and printing is performed on the print paper 110 while being controlled.

  Here, the liquid is ejected onto the print paper 110 as ink, but the liquid ejected from the droplet ejection head is not limited to ink. For example, in an application to be discharged onto a substrate to be a color filter, a light emitting element is used in an application to be discharged onto a substrate of a display panel (OLED or the like) using an electroluminescent element such as a liquid containing a color filter pigment or an organic compound. For example, a liquid containing a conductive metal and a liquid containing a conductive metal may be discharged from a droplet discharge head provided in each device. In addition, when the droplet discharge head is used as a dispenser and used for discharging onto a substrate that is a microarray of biomolecules, DNA (Deoxyribo Nucleic Acids: deoxyribonucleic acid), other nucleic acids (for example, Ribo Nucleic Acid: ribonucleic acid, Peptide (Nucleic Acids: peptide nucleic acids, etc.) A liquid containing a probe such as a protein may be discharged. In addition, it can also be used for discharging dyes such as cloth.

Embodiment 5. FIG.
In the above-described embodiment, the discharge control of the droplet discharge head has been described. For example, other types of microfabricated electrostatic actuators such as a motor, a sensor, a vibration element (resonator) such as a SAW filter, a mirror device, and the like. In addition, a control method that applies a drive to perform work after the movable electrodes of the parallel plates are stabilized at a predetermined position by applying a voltage in advance is also applied to a sensor such as a pressure sensor. Can do.

2 is an exploded view of a droplet discharge head according to Embodiment 1. FIG. It is sectional drawing of a droplet discharge head. 2 is a diagram illustrating a configuration centering on a drive control circuit 40. FIG. It is a figure showing the relationship between gap length and the discharge characteristic of a droplet. It is a figure showing the example of a relationship of the peak drive voltage, gap length, and discharge characteristics. It is a figure showing the example of a waveform of the voltage in a certain drive cycle, and the example of a setting of each mode. It is an external view of a droplet discharge device using a droplet discharge head. It is a figure showing an example of the main structural means of a droplet discharge apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electrode substrate, 11 Recessed part, 12 Individual electrode, 13 Lead part, 14 Terminal part, 15 Liquid supply port, 20 Cavity board, 21 Discharge chamber, 22 Vibration plate, 23 Insulating film, 24 Reservoir, 25 Sealing material, 26 Electrode Extraction port, 27 Common electrode terminal, 30 Nozzle substrate, 31 Nozzle, 32 Diaphragm, 33 Orifice, 40 Drive control circuit, 41 Head control unit, 42a CPU, 42b Bus, 43a ROM, 43b RAM, 43c Character generator, 45 Logic gate Array, 46a COM generation circuit, 46b Drive pulse generation circuit, 47 Connector, 48 Driver IC, 49 Wiring, 50 External device, 51 Bus, 60 Power supply circuit, 100 Printer, 101 Drum, 102 Droplet discharge head, 103 Paper pressure roller 104 feed Di, 105 belt, 106 motor, 107 print control means 110 print paper.

Claims (7)

Discharge control of a droplet discharge head comprising a nozzle, a flow path communicating with the nozzle, an individual electrode, and a diaphragm that is opposed to the individual electrode at a predetermined distance and is provided in a part of the flow path In the method
Applying a first voltage between the diaphragm and the individual electrode to generate an electrostatic force, and displacing the diaphragm to a position at a predetermined distance from the individual electrode;
A second voltage for discharging a droplet is further applied between the diaphragm and the individual electrode, an electrostatic force is generated between the diaphragm and the individual electrode, and the diaphragm is displaced. And a step of discharging the droplets by pressurizing the liquid in the flow path.   By applying the second voltage, the first voltage is applied in accordance with the interval between the individual electrode that maximizes the droplet ejection speed and the diaphragm, and the diaphragm is displaced. The droplet discharge head discharge control method according to claim 1.   3. The droplet discharge head ejection control method according to claim 1, wherein a time for applying the first voltage is made longer than a time for applying the second voltage.   Applying the second voltage between the diaphragm and the individual electrode according to a voltage value arbitrarily selected from a plurality of voltage values, displacing the diaphragm, and discharging droplets. The discharge control method for a droplet discharge head according to any one of claims 1 to 3. Droplets in which an interval between the diaphragm and the individual electrodes is formed in advance so that the droplet discharge amount is maximized when the maximum voltage among the plurality of voltage values is applied as the second voltage. In the discharge head,
5. The ejection of the droplet ejection head according to claim 4, wherein when the maximum voltage is applied as the second voltage, the first voltage is set to 0 V and the displacement of the diaphragm is set to 0. 6. Control method.   A discharge control method for a droplet discharge device, wherein the discharge control method for a droplet discharge device is controlled by applying the discharge control method for a droplet discharge head according to claim 1.   A liquid droplet ejection apparatus that performs liquid droplet ejection onto an ejection target object by performing ejection control using the liquid ejection method of the liquid droplet ejection head according to claim 1.

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