JP2005211711A - Controlling method for droplet ejecting head, droplet ejecting device, and production method for the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controlling method for a droplet ejecting head and a droplet ejecting device, or the like, by which clogging of a nozzle opening of the droplet ejecting head, or the like, can be eliminated with high accuracy and further wasteful consumption of liquid can be suppressed. <P>SOLUTION: The droplet ejecting head is provided with a cavity for accommodating predetermined liquid, a piezoelectric crystal element which generates pressure corresponding to an applied driving signal in the cavity and the nozzle opening through which the liquid pressurized by the piezoelectric crystal element is ejected as a droplet. Control for compulsorily ejecting the droplet from the nozzle opening is carried out by changing the driving signal impressed to the piezoelectric crystal element in accordance with time when the nozzle opening of the droplet ejecting head is capped. For example, when capping time is short, compulsive ejection driving signal DK is impressed, and when capping time is long, heating driving signal DH and the compulsive ejection driving signal DK are impressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for controlling a droplet discharge head that discharges a predetermined liquid as droplets, a droplet discharge apparatus including the droplet discharge head, and a device manufacturing method using the method or apparatus.

  A droplet discharge head provided in the droplet discharge apparatus includes a pressure generation chamber that stores a predetermined liquid, a piezoelectric element that pressurizes the pressure generation chamber, and a nozzle opening that communicates with the pressure generation chamber. The liquid in the pressure generating chamber is pressurized with a piezo element, thereby discharging a minute amount of liquid as a droplet from the nozzle opening. Since the liquid in the vicinity of the nozzle opening is in direct contact with the outside air, the viscosity increases (thickens) by drying. When the liquid is thickened, the nozzle opening may be clogged, resulting in defective ejection of droplets.

In order to prevent droplet ejection failure, the droplet ejection device performs flushing to forcibly eject droplets regularly or irregularly and to discharge the thickened liquid outside the pressure generation chamber. In addition, when the discharge failure of the droplet is not solved by the flushing, after the suction operation is performed from the nozzle opening of the droplet discharge head, cleaning is performed by wiping the nozzle plate surface with a wiper. For an example of conventional cleaning, see, for example, Patent Documents 1 and 2 below.
JP 2003-118133 A JP 2002-079693 A

  By the way, as described above, flushing is performed so as not to cause clogging of the droplet discharge head, and cleaning is performed when clogging occurs, but when clogging is not eliminated, flushing and Cleaning is performed. For this reason, there has been a problem that the amount of liquid discharged from the nozzle openings where clogging does not occur increases and the liquid is wasted. In addition, if the surface on which the nozzle openings are formed is wiped with a wiper several times, the life of the wiper is shortened and the water repellency of the surface on which the nozzle openings of the droplet discharge head are formed is reduced. As a result, there has been a problem that a droplet ejection failure is caused.

  Further, in recent years, the droplet discharge device has been used for the manufacture of various devices having fine patterns such as color filters, microlens arrays, and the like used in liquid crystal display devices, and a plurality of droplet discharge heads. By providing this, the throughput (the number of devices that can be manufactured per unit time) is to be improved as much as possible. Therefore, a reduction in throughput due to clogging of the nozzle openings must be avoided as much as possible.

  The present invention has been made in view of the above circumstances, and can prevent clogging of the nozzle opening of the droplet discharge head with high accuracy and suppress wasteful consumption of liquid. It is an object of the present invention to provide a droplet discharge head control method and a droplet discharge apparatus that do not cause deterioration of the performance of the discharge head, and a device manufacturing method that can manufacture a device without causing a decrease in throughput.

In order to solve the above problems, a method for controlling a droplet discharge head includes a cavity for storing a predetermined liquid, a pressure generating element for generating a pressure in the cavity according to an applied drive signal, and the pressure generation A method for controlling a liquid droplet ejection head having a nozzle opening through which the liquid pressurized by an element is ejected as a liquid droplet, the time measuring step for measuring the time when the nozzle opening is sealed, and the time measuring step And a control step for performing control to forcibly eject the droplet from the nozzle opening by changing a drive signal applied to the pressure generating element in accordance with the time measurement result.
According to this invention, the droplet discharge head is forcibly discharged from the nozzle opening by changing the drive signal applied to the pressure generating element according to the time when the droplet discharge head is sealed in the sealing portion. Clogging of the nozzle opening of the droplet discharge head can be eliminated with high accuracy. In addition, since the clogging of the nozzle opening is eliminated with high accuracy, the number of cleaning of the droplet discharge head can be reduced, resulting in a decrease in the performance of the droplet discharge head, such as a decrease in water repellency. There is no. Further, since the number of cleanings is reduced, it is possible to reduce the consumption of consumable parts of the cleaning device.
Further, in the method for controlling a droplet discharge head according to the present invention, the drive signal applied to the pressure generating element in the control step is half the liquid exclusion volume that can be excluded from the cavity by pressurization of the pressure generating element. And a forced ejection drive signal for forcibly ejecting the liquid droplets as droplets from the nozzle openings.
According to the present invention, the liquid in the cavity is forcibly ejected by applying a forced ejection drive signal for ejecting half of the excluded volume of the liquid as a droplet from the nozzle opening to the pressure generating element. This is extremely suitable for eliminating clogging of the nozzle opening of the head. Here, the excluded volume refers to the volume of liquid that is excluded from the cavity when the maximum pressure is applied to the cavity. In the present invention, not all of the excluded volume, but half of the excluded volume is discharged from the nozzle opening, because the cavity is not sealed except for the nozzle opening, so that all of the excluded volume is discharged from the nozzle opening. It is because it cannot be made. Half of the excluded volume that is not discharged from the nozzle opening is excluded outside the cavity from a location other than the nozzle opening (for example, a supply port that supplies a predetermined liquid into the cavity).
In the droplet discharge head control method of the present invention, the drive signal applied to the pressure generating element in the control step includes a heating drive signal for heating the liquid in the cavity.
According to the present invention, since the heating drive signal for heating the liquid is included in the drive signal applied to the pressure generating element, the viscosity of the liquid can be reduced, and as a result, the nozzle opening is clogged. Furthermore, it can be solved with high accuracy.
In the method for controlling a droplet discharge head according to the present invention, the drive signal applied to the pressure generating element in the control step generates a very small pressure that does not cause the droplet to be discharged from the nozzle opening. It is characterized by including.
According to the present invention, since the minute driving signal for generating a minute pressure is included in the driving signal applied to the pressure generating element, it corresponds to the pressure generating element to which the forced ejection driving signal and the minute driving signal are not applied. The meniscus at the nozzle opening can be vibrated, and as a result, thickening of the liquid can be prevented.
In addition, the method for controlling a droplet discharge head according to the present invention includes a detection step of detecting whether or not the droplet is discharged from each of the nozzle openings, and the control step depends on a detection result of the detection step. Control for changing the type of the drive signal applied to the pressure generating element is performed.
According to the present invention, the presence or absence of liquid droplet ejection from each nozzle opening is detected in advance, and control is performed to change the type of drive signal applied to the pressure generating element according to the detection result. Only when a problem such as clogging in which droplets are not ejected occurs, droplets are ejected from the nozzle opening where the problem has occurred in order to eliminate the malfunction. By performing such control, for example, liquid is not wasted in comparison with the case where the forced ejection drive signal is periodically applied, so that the liquid consumption can be suppressed and the forced ejection drive signal is applied. It is possible to save the time required for ejecting droplets.
Further, in the method for controlling a droplet discharge head according to the present invention, the control step generates a drive signal including the forced discharge drive signal, the heating drive signal, and the minute drive signal in one discharge cycle. And a selection step of selecting one or two of the forced ejection drive signal, the heating drive signal, and the minute drive signal according to the detection result of the detection step and applying the selected one to the pressure generating element. It is characterized by including.
According to the present invention, a drive signal including a forced ejection drive signal, a heating drive signal, and a minute drive signal is generated in one ejection cycle of the droplet ejection head, and these drive signals are generated according to the detection result of the detection step. Since one or two are selected and applied to the pressure generating elements, a drive signal to be applied can be applied to each pressure generating element in a short time even when there are many pressure generating elements.
Further, in the method for controlling a droplet discharge head according to the present invention, the selection step is performed on the pressure generating element corresponding to the nozzle opening that is detected in the detection step that the droplet is not discharged. The forced ejection drive signal is selected and applied.
According to the present invention, since the forced ejection drive signal is selected from among a plurality of types of drive signals and applied to the pressure generating element corresponding to the nozzle opening from which the droplet is not ejected, the clogged nozzle opening is recovered. Very suitable above.
In addition, the method for controlling a droplet discharge head according to the present invention is characterized in that the selection step selects the heating drive signal in addition to the forced discharge drive signal.
According to the present invention, the heating drive signal is selected and applied in addition to the forced ejection drive signal to the pressure generating element corresponding to the nozzle opening from which droplets are not ejected. Since the solid matter that has been lowered or solidified by drying can be dissolved, the clogged nozzle opening can be recovered with high accuracy.
Further, in the method for controlling a droplet discharge head according to the present invention, the selection step is performed on the pressure generating element corresponding to the nozzle opening that is detected that the droplet is discharged in the detection step. The minute drive signal is selected and applied.
According to the present invention, since a minute driving signal is applied to the pressure generating element corresponding to the nozzle opening from which the droplet is discharged, the meniscus at the nozzle opening can be vibrated, and as a result, the liquid increases. Can prevent stickiness.
Further, in the method for controlling a droplet discharge head according to the present invention, the control step performs a control to increase or decrease the number of times that the droplet is forcibly discharged from the nozzle opening in accordance with a timing result of the timing step. It is a feature.
According to the present invention, the number of times that the forced ejection drive signal is applied to the pressure generating element is controlled according to the type of the liquid to control the number of times that the liquid is ejected. Accordingly, an appropriate amount of liquid can be discharged. As a result, clogging of the nozzle openings can be effectively eliminated.
In order to solve the above problems, a droplet discharge device according to the present invention includes a cavity for storing a predetermined liquid, a pressure generating element for generating a pressure in the cavity according to an applied drive signal, and the pressure generation A liquid comprising: a liquid droplet ejection head having a nozzle opening through which the liquid pressurized by an element is ejected as a liquid droplet; and a capping device having a sealing portion that seals the nozzle opening of the liquid droplet ejection head. A droplet discharge device, which generates a drive signal including a plurality of different drive signals in one discharge cycle, and a timing unit that measures the time when the nozzle opening of the droplet discharge head is sealed in the sealing portion A drive signal generating means for performing the nozzle opening by changing a drive signal applied to the pressure generating element among the drive signals generated by the drive signal generating means in accordance with a timing result of the time measuring means. It is characterized in that it comprises a control means for forcibly controlling to eject al the droplet.
According to the present invention, the nozzle applied by changing the drive signal applied to the pressure generating element among the drive signals generated by the drive signal generating means according to the sealing time of the droplet discharge head timed by the time measuring means. Since the control for forcibly discharging the droplets from the openings is performed by the control means, clogging of the nozzle openings of the droplet discharge head can be eliminated with high accuracy. In addition, since the clogging of the nozzle opening is eliminated with high accuracy, the number of cleaning of the droplet discharge head can be reduced, resulting in a decrease in the performance of the droplet discharge head, such as a decrease in water repellency. There is no. Further, since the number of cleanings is reduced, it is possible to reduce the consumption of consumable parts of the cleaning device.
In the droplet discharge device of the present invention, the drive signal generation means forcibly forces half of the excluded volume of the liquid that can be excluded from the cavity by pressurization of the pressure generating element as a droplet from the nozzle opening. Including a forced ejection drive signal to be ejected, a heating drive signal to heat the liquid in the cavity, and a minute drive signal to generate a minute pressure that does not cause the droplet to be ejected from the nozzle opening. Yes.
According to the present invention, the drive signal generation unit generates a drive signal including a forced discharge drive signal, a heating drive signal, and a minute drive signal in one discharge cycle. A signal can be applied to the pressure generating element corresponding to the nozzle opening.
In addition, the droplet discharge device of the present invention includes a detection device that detects whether or not the droplet is discharged from each of the nozzle openings, and the control unit performs the compulsion according to the detection result of the detection device. One or two of the ejection drive signal, the heating drive signal, and the minute drive signal are selected and controlled to be applied to the pressure generating element.
According to the present invention, the presence / absence of liquid droplet ejection from each of the nozzle openings is detected in advance, and one of the forced ejection drive signal, the heating drive signal, and the minute drive signal or the Since two are selected and applied to the pressure generating element, only when a problem such as clogging of the nozzle opening does not occur, droplets are discharged from the nozzle opening where the problem has occurred. Is called. As a result, wasteful discharge of liquid is not performed as compared with, for example, a case where the forced ejection drive signal is periodically applied, so that liquid consumption can be suppressed and droplets generated by the application of the forced ejection drive signal can be suppressed. Time required for discharge can be saved.
In the liquid droplet ejection apparatus according to the present invention, the control unit may perform the forced ejection with respect to the pressure generating element corresponding to the nozzle opening that is detected by the detection device as not ejecting the liquid droplets. The drive signal is selected and applied.
According to the present invention, since the forced ejection drive signal is selected from among a plurality of types of drive signals and applied to the pressure generating element corresponding to the nozzle opening from which the droplet is not ejected, the clogged nozzle opening is recovered. Very suitable above.
In the droplet discharge device of the present invention, the control unit selects the heating drive signal in addition to the forced discharge drive signal.
According to the present invention, the heating drive signal is selected and applied in addition to the forced ejection drive signal to the pressure generating element corresponding to the nozzle opening from which droplets are not ejected. Since the solid matter that has been lowered or solidified by drying can be dissolved, the clogged nozzle opening can be recovered with high accuracy.
Further, in the droplet discharge device of the present invention, the control unit performs the micro-driving with respect to the pressure generating element corresponding to the nozzle opening that is detected by the detection device to discharge the droplet. It is characterized in that a signal is selected and applied.
According to the present invention, since a minute driving signal is applied to the pressure generating element corresponding to the nozzle opening from which the droplet is discharged, the meniscus at the nozzle opening can be vibrated, and as a result, the liquid increases. Can prevent stickiness.
In the liquid droplet ejection apparatus according to the present invention, the control unit performs control to increase or decrease the number of times the liquid droplets are forcibly ejected from the nozzle opening according to a timing result of the timing unit. .
According to the present invention, the number of times that the forced ejection drive signal is applied to the pressure generating element is controlled according to the type of the liquid to control the number of times that the liquid is ejected. Accordingly, an appropriate amount of liquid can be discharged. As a result, clogging of the nozzle openings can be effectively eliminated.
The device manufacturing method of the present invention is a method for manufacturing a device including a workpiece having a functional pattern formed at a predetermined location, and the method for controlling a droplet discharge device according to any one of the above, or the above A preliminary discharge step of discharging the predetermined liquid from the nozzle opening provided in the droplet discharge head using the droplet discharge device according to any one of the above, and a droplet discharge head that has undergone the preliminary discharge step, And a step of forming droplets on the workpiece to form the pattern.
According to the present invention, a droplet discharge head that eliminates or prevents clogging of a nozzle opening using the droplet discharge device control method or the droplet discharge device according to any one of the above, Since the pattern is formed by discharging droplets onto the workpiece, wasteful consumption of a predetermined liquid can be suppressed, and the droplet discharge time for forming the pattern can be extended. As a result, the manufacturing cost of the device can be reduced and the throughput can be improved.

  Hereinafter, a droplet discharge head control method, a droplet discharge apparatus, and a device manufacturing method according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Droplet discharge device]
FIG. 1 is a perspective view showing a schematic configuration of a droplet discharge device according to an embodiment of the present invention. In the following description, if necessary, an XYZ orthogonal coordinate system is set in the drawing, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. In the XYZ orthogonal coordinate system, the XY plane is set to a plane parallel to the horizontal plane, and the Z axis is set to the vertically upward direction. In this embodiment, the movement direction of the discharge head (droplet discharge head) 20 is set to the X direction, and the movement direction of the stage ST is set to the Y direction.

  As shown in FIG. 1, the droplet discharge device IJ of the present embodiment is supported on a base 10, a stage ST that supports a substrate P such as a glass substrate on the base 10, and above the stage ST (+ Z direction), An ejection head 20 that can eject predetermined droplets onto the substrate P is configured. Between the base 10 and the stage ST, a first moving device 12 that supports the stage ST so as to be movable in the Y direction is provided. A second moving device 14 that supports the ejection head 20 so as to be movable in the X direction is provided above the stage ST.

  A tank 16 that stores a solvent (predetermined liquid) of liquid droplets discharged from the discharge head 20 via the flow path 18 is connected to the discharge head 20. A capping unit 22 and a cleaning unit 24 are arranged on the base 10. The control device 26 controls each part (for example, the first moving device 12 and the second moving device 14) of the droplet discharge device IJ to control the entire operation of the droplet discharge device IJ.

  The first moving device 12 is installed on the base 10 and is positioned along the Y-axis direction. The first moving device 12 includes, for example, a linear motor, and includes guide rails 12a and 12a, and a slider 12b provided to be movable along the guide rail 12a. The slider 12b of the linear motor type first moving device 12 can be positioned by moving in the Y-axis direction along the guide rail 12a.

The slider 12b includes a motor 12c for rotating around the Z axis (θ _Z ). The motor 12c is, for example, a direct drive motor, and the rotor of the motor 12c is fixed to the stage ST. Thus, by energizing the motor 12c, the rotor and the stage ST can rotate along the _θZ direction to index (rotate index) the stage ST. That is, the first moving device 12 is capable of moving the stage ST in the Y-axis direction and theta _Z direction. The stage ST holds the substrate P and positions it at a predetermined position. The stage ST has a suction holding device (not shown), and the suction holding device operates to suck and hold the substrate P on the stage ST through a suction hole (not shown) provided in the stage ST. To do.

  The second moving device 14 is mounted upright with respect to the base 10 using the support columns 28a and 28a, and is mounted at the rear portion 10a of the base 10. The second moving device 14 is constituted by a linear motor and is supported by a column 28b fixed to the columns 28a and 28a. The second moving device 14 includes a guide rail 14a supported by the column 28b, and a slider 14b supported so as to be movable in the X-axis direction along the guide rail 14a. The slider 14b can be positioned by moving in the X-axis direction along the guide rail 14a. The ejection head 20 is attached to the slider 14b.

  The discharge head 20 has motors 30, 32, 34, and 36 as swing positioning devices. If the motor 30 is driven, the ejection head 20 can be moved up and down along the Z direction, and the ejection head 20 can be positioned at an arbitrary position in the Z direction. When the motor 32 is driven, the ejection head 20 can be swung along the β direction around the Y axis, and the angle of the ejection head 20 can be adjusted. By driving the motor 34, the ejection head 20 can be swung along the γ direction around the X axis, and the angle of the ejection head 20 can be adjusted. If the motor 36 is driven, the ejection head 20 can be swung along the α direction around the Z axis, and the angle of the ejection head 20 can be adjusted.

  As described above, the ejection head 20 shown in FIG. 1 is linearly movable in the Z direction, and the slider 14b can be adjusted by swinging along the α direction, the β direction, and the γ direction. It is supported by. The position and posture of the discharge head 20 are accurately controlled by the control device 26 so that the position or posture of the droplet discharge surface 20a with respect to the substrate P on the stage ST side becomes a predetermined position or a predetermined posture. Note that a plurality of nozzle openings for discharging droplets are provided on the droplet discharge surface 20a of the discharge head 20.

  As the droplets ejected from the ejection head 20 described above, an ink containing a coloring material, a dispersion containing a material such as metal fine particles, a hole injection material such as PEDOT: PSS, and an organic EL substance such as a light emitting material are used. Liquid droplets containing various materials such as high-viscosity functional liquids such as liquid solutions and liquid materials, functional liquids containing microlens materials, and biopolymer solutions containing proteins and nucleic acids are used. The

  Here, the configuration of the ejection head 20 will be described. FIG. 2 is an exploded perspective view of the ejection head 20, and FIG. 3 is a perspective view showing a part of the main part of the ejection head 20. The discharge head 20 shown in FIG. 2 includes a nozzle plate 110, a pressure chamber substrate 120, a vibration plate 130, and a housing 140. As shown in FIG. 2, the pressure chamber substrate 120 includes a cavity 121, a side wall 122, a reservoir 123, and a supply port 124. The cavity 121 is a pressure chamber and is formed by etching a substrate such as silicon. The side wall 122 is configured to partition between the cavities 121, and the reservoir 123 is configured as a common flow path that can supply a predetermined liquid when the cavities 121 are filled with the predetermined liquid. The supply port 124 is configured to be able to introduce a predetermined liquid into each cavity 121.

  Further, as shown in FIG. 3, the diaphragm 130 is configured to be bonded to one surface of the pressure chamber substrate 120. The diaphragm 130 is provided with a piezoelectric element 150 which is a part of the piezoelectric device described above. The piezoelectric element 150 is a ferroelectric crystal having a perovskite structure, and is formed on the diaphragm 130 in a predetermined shape. The piezoelectric element 150 is configured to be capable of causing a volume change in response to a drive signal supplied from the control device 26. The nozzle plate 110 is bonded to the pressure chamber substrate 120 so that the nozzle openings 111 are arranged at positions corresponding to the plurality of cavities (pressure chambers) 121 provided in the pressure chamber substrate 120. The pressure chamber substrate 120 to which the nozzle plate 110 is bonded is further fitted in a housing 140 to form the droplet discharge head 20 as shown in FIG.

  In order to eject droplets from the ejection head 20, first, the control device 26 supplies a drive signal for ejecting the droplets to the ejection head 20. The predetermined liquid flows into the cavity 121 of the ejection head 20, and when a driving signal is supplied to the ejection head 20, the piezoelectric element 150 provided in the ejection head 20 changes in volume according to the driving signal. This volume change deforms the diaphragm 130 and changes the volume of the cavity 121. As a result, a droplet is ejected from the nozzle opening 111 of the cavity 121. In the cavity 121 from which the liquid droplets have been discharged, the liquid droplets reduced by the discharge are newly supplied from the tank 16.

  The discharge head 20 described with reference to FIGS. 2 and 3 has a configuration in which a volume change is generated in the piezoelectric element 150 to discharge droplets. However, heat is applied to a predetermined liquid by a heating element. A head configuration in which droplets are ejected by expansion may be used. Further, an ejection head that ejects droplets by causing a volume change by deforming the diaphragm by static electricity may be used.

  Returning to FIG. 1, the second moving device 14 can selectively position the discharge head 20 above the cleaning unit 24 or the capping unit 22 by moving the discharge head 20 in the X-axis direction. That is, even during the device manufacturing operation, for example, if the ejection head 20 is moved onto the cleaning unit 24, the ejection head 20 can be cleaned. Further, if the ejection head 20 is moved onto the capping unit 22, capping is performed on the droplet ejection surface 20 a of the ejection head 20, the droplet is filled into the cavity 121, or ejection due to clogging of the nozzle opening 111 or the like. It becomes possible to recover defects.

  That is, the cleaning unit 24 and the capping unit 22 are arranged on the rear portion 10a side on the base 10 and directly below the moving path of the ejection head 20 and separated from the stage ST. Since the loading and unloading operations of the substrate P with respect to the stage ST are performed on the front portion 10b side of the base 10, the cleaning unit 24 or the capping unit 22 does not hinder the operation.

  The cleaning unit 24 includes a wiper that wipes off the surface on which the nozzle openings 111 are formed. The cleaning of the nozzle openings 111 and the like of the ejection head 20 can be performed regularly or at any time during the device manufacturing process or during standby. The capping unit 22 performs capping on the droplet discharge surface 20a during standby when the device is not manufactured so as not to dry the droplet discharge surface 20a of the discharge head 20, or is used when filling the cavity 221 with droplets. Also, the ejection head 20 in which ejection failure has occurred is recovered.

  Next, the capping unit 22 will be described in detail. 4A and 4B are diagrams illustrating the configuration of the capping unit 22, in which FIG. 4A is a plan view of the capping unit 22 viewed from the ejection head 20 side, and FIG. 4B is a diagram in FIG. It is a cross-sectional arrow view along AA. As shown in FIGS. 4A and 4B, the capping unit 22 includes a main body 40, a capping unit 42, a communication pipe 44, and a pump (negative pressure supply device) 46.

  The capping portion 42 includes a wetting member 42b fitted into a recess 42a formed in the main body 40 and a protruding portion 42c protruding from the upper surface 40a of the main body 40. In addition, a communication pipe 44 penetrating the lower surface 40 of the main body 40 is connected to the bottom surface of the recess 42a. Here, the wetting member 42b has excellent absorbability with respect to the droplets ejected from the ejection head 20, and maintains a wet state when the droplets are absorbed, and is made of a material such as sponge, for example. The pump 46 sucks and depressurizes the capping unit 42 via the communication pipe 44 (supplies a negative pressure). The pump 46 is electrically connected to the control device 26, and its drive is controlled under the control of the control device 26.

  Returning to FIG. 1, the droplet discharge device IJ of the present embodiment determines whether or not there is a nozzle opening 111 from which droplets are not discharged among the plurality of nozzle openings 111 provided on the droplet discharge surface 20 a of the discharge head 20. A discharge detection device 38 for detecting (presence / absence of missing dots) is provided. The ejection detection device 38 includes, for example, a laser light source and a light receiving element that receives laser light from the laser light source. These laser light source and light receiving element are arranged so as to sandwich the locus of droplets ejected from each of the nozzle openings 111 when the position of the ejection head 20 in the X direction is positioned at a predetermined position. When droplets are ejected in order from each of 111, the presence or absence of missing dots is detected based on the presence or absence of a change in the amount of light received by the light receiving element.

  Further, the discharge detection device 38 is optically conjugate with the printing unit by a printing unit configured to print droplets from each of the nozzle openings 111 and clean the printing surface with a wiper or the like, and an optical lens or the like. It can also be configured with an imaging device such as a CCD (Charge Coupled Device) set to. In the case of such a configuration, the presence or absence of missing dots is obtained by performing image processing on an image signal obtained by ejecting droplets from each of the nozzle openings 111 to print a print surface and imaging the print surface with an image sensor. Detect the presence of

  Next, the electrical functional configuration of the droplet discharge device IJ of this embodiment will be described. FIG. 5 is a block diagram showing an electrical functional configuration of the droplet discharge device according to the embodiment of the present invention. In FIG. 5, blocks corresponding to the members shown in FIGS. 1 to 4 are denoted by the same reference numerals. As shown in FIG. 5, the electrical configuration for controlling the droplet discharge device IJ includes a control computer 50, a control device 26, and a driving integrated circuit 60.

  The control computer 50 includes, for example, an internal storage device such as a CPU (Central Processing Unit), a RAM (Random Access Memory) and a ROM (Read Only Memory), an external storage device such as a hard disk and a CD-ROM, and a liquid crystal display device or CRT (CRT). A control signal for controlling the operation of the droplet discharge device IJ is output in accordance with a program stored in a ROM or a hard disk. The control computer 50 is connected to the control device 26 provided in the droplet discharge device IJ shown in FIG. 1 using, for example, a cable.

  The control device 26 includes an arithmetic control unit 52, a drive signal generation unit 54, and a timer unit 56. The arithmetic control unit 52 drives the first moving device 12, the second moving device 14, and the motors 30 to 36 based on a control signal input from the control computer 50 and a control program stored therein in advance, The operation of the pump 46 provided in the capping unit 22 is controlled.

  The arithmetic control unit 52 also outputs various data (drive signal generation data) for generating various drive signals for driving the plurality of piezoelectric elements 150 provided in the ejection head 20 to the drive signal generation unit 54. Further, the arithmetic control unit 52 generates selection data based on the control program and outputs the selection data to the switching signal generation unit 62 provided in the driving integrated circuit 60. This selection data includes nozzle selection data for designating the piezoelectric element 150 to which the drive signal is applied and waveform selection data for designating the drive signal applied to the piezoelectric element 150.

  In addition, the arithmetic control unit 52 counts the time during which the ejection head 20 is capped (sealed) using the capping unit 22 using the timer unit 56 and the time during which the ejection head 20 is not capped, and the pump The time for driving 46 is controlled. Further, based on the detection result of the discharge detection device 38, the forced discharge (flushing) of droplets from the nozzle openings 111 provided in the discharge head 20 is controlled, and the capping time, the number of times of cleaning, and the like are controlled.

  The drive signal generator 54 generates various drive signals having a predetermined shape based on the drive signal generation data and outputs the generated drive signals to the switch circuit 64. The drive signal generated by the drive signal generation unit 54 includes, for example, a normal drive signal, a forced ejection drive signal, a heating drive signal, and a minute drive signal. The normal drive signal is a drive signal for discharging a predetermined amount of liquid droplets from the nozzle opening 111, and the forced discharge drive signal is a drive signal for forcibly discharging half of the excluded volume of liquid from the specific nozzle opening 111. It is. Here, the excluded volume refers to the volume of liquid excluded from the cavity 221 when the maximum amount of deformation is applied to the cavity 221 with the deformation amount of the piezoelectric element 150 being maximized.

  The heating drive signal is a drive signal that heats the liquid in the cavity 121 to reduce the viscosity and melts the solid matter solidified in the vicinity of the nozzle opening 111. The minute driving signal is a driving signal that vibrates the meniscus in the nozzle opening 111 by causing the piezoelectric element 150 to vibrate to such an extent that no liquid droplets are ejected from the nozzle opening 111, thereby preventing the liquid from being thickened in the vicinity of the nozzle opening 111. is there. The timer unit 56 receives, for example, a clock start signal and a clock time output from the arithmetic control unit 52, and outputs a clock completion signal when the clock time has elapsed since the clock was started.

  The driving integrated circuit 60 is provided in the ejection head 20 and includes a switching signal generator 62 and a switch circuit 64. The switching signal generator 62 generates a switching signal that instructs conduction / non-conduction of the drive signal to each piezoelectric element 150 based on the selection data output from the arithmetic control unit 52, and outputs the switching signal to the switch circuit 64. The switch circuit 64 is provided for each piezoelectric element 150 and outputs a drive signal designated by the switching signal to the piezoelectric element 150.

  Here, an example of the drive signal generated by the drive signal generation unit 54 and the operation of the ejection head will be briefly described. FIG. 6 is a diagram schematically illustrating the waveform of one cycle of the normal drive signal generated by the drive signal generation unit 54 and the operation of the ejection head. As shown in FIG. 6A, the normal drive signal is basically constant up to the maximum potential VPS from time T1 to time T2 after the voltage value starts from the intermediate potential Vm (hold pulse L1). (Charge pulse L2), and the maximum potential VPS is maintained for a predetermined time from time T2 to time T3 (hold pulse L3). Next, after falling from the time T3 to the time T4 with a constant slope to the lowest potential VLS (discharge pulse L4), the minimum potential VLS is maintained for a predetermined time from the time T4 to the time T5 (hold pulse). L5). Then, from time T5 to time T6, the voltage value rises at a constant slope to the intermediate potential Vm (charging pulse L6).

  When the normal drive signal described above is applied to the piezoelectric element 150, the piezoelectric element 150 performs the operation shown in FIGS. 6B to 6D, whereby a predetermined liquid is discharged from the nozzle opening 111 as a droplet. Discharged. First, when a charging pulse L2 in which the voltage value of the normal drive signal rises gently between time T1 and time T2 in FIG. 6A is applied to the piezoelectric element 150, FIG. 6B shows. As shown in the figure, the piezoelectric element 150 bends in the direction in which the volume of the cavity 121 is gradually expanded, and a negative pressure is generated in the cavity 121. As a result, a predetermined liquid is supplied from the reservoir 123 to the cavity 121. Further, as shown in the drawing, the liquid viscous material located in the vicinity of the nozzle opening 111 is slightly drawn toward the inside of the cavity 121, whereby the meniscus is drawn into the nozzle opening 111.

  Next, after a hold pulse L3 that holds the voltage value of the normal drive signal at the maximum potential VPS is applied to the piezoelectric element 150 between time T2 and time T3, the discharge pulse L4 is generated between time T3 and time T4. When applied, the piezoelectric element 150 rapidly bends in the direction of contracting the volume of the cavity 121, and a positive pressure is generated in the cavity 121. As a result, as shown in FIG. 6C, a predetermined liquid is ejected from the nozzle opening 111 as the droplet D1.

  When the droplet D1 is ejected, a hold pulse L5 that maintains the minimum potential VLS is applied to the piezoelectric element 150 from time T4 to time T5, and then the intermediate potential Vm from time T5 to time T6. A charging pulse L6 that rises at a constant slope is applied to the piezoelectric element 150. When the charging pulse L6 is applied to the piezoelectric element 150, the piezoelectric element 150 is deformed as shown in FIG. 6D, and a negative pressure is generated in the cavity 121. As a result, the predetermined liquid is supplied from the reservoir 123 to the cavity 121, and the predetermined liquid located in the vicinity of the opening of the nozzle opening 111 is slightly drawn toward the inside of the cavity 121, as shown in FIG. The meniscus is kept constant. Thus, for example, as the maximum potential VPS is higher or the slope of the discharge pulse L4 is steeper, the weight of the liquid viscous material discharged from the nozzle opening 111 per dot is larger.

  Next, the normal drive signal and the forced ejection drive signal are compared. FIGS. 7A and 7B are diagrams for explaining the normal drive signal, the forced ejection drive signal, and the excluded volume. FIG. 7A is a diagram illustrating the normal drive signal and the forced ejection drive signal, and FIG. FIG. In FIG. 7A, the drive signal denoted by reference numeral DN is a normal drive signal, and the drive signal denoted by reference numeral DK is a forced ejection drive signal. The normal drive signal DN is a drive signal whose voltage value changes between the maximum potential VPS and the minimum potential VLS, but the forced ejection drive signal DK has a potential Vmax higher than the maximum potential VPS of the normal drive signal DN and the normal drive signal DN. This is a drive signal whose voltage value changes between a potential Vmin lower than the lowest potential LVS of the drive signal DN. Here, the potential Vmax is set to a value that maximizes the amount of deformation of the piezoelectric element 150, and the potential Vmin and the potential Vc are set to values that can recover the deformation.

  That is, when the forced ejection drive signal DK is applied to the piezoelectric element 150, the deformation amount of the piezoelectric element 150 is maximized, and as a result, the volume change of the cavity 121 is maximized. The maximum amount of change in the volume of the cavity 121 is the excluded volume. When the forced ejection drive signal DK is applied to the piezoelectric element 150, the ejection head 20 operates similarly to the operations shown in FIGS. 6B to 6D except for the magnitude of the displacement amount of the piezoelectric element 150. I do. In FIG. 7B, a location indicated by reference sign dV (a hatched location) is an excluded volume, which is the maximum volume of the liquid that is excluded from the cavity 221 at a time. However, the cavity 121 is not hermetically sealed except for the nozzle opening 111 and is communicated with the reservoir 123 via the supply port 124 as shown in FIG. 2 and FIG. The maximum amount of liquid that flows out to the nozzle 123 and is discharged from the nozzle opening 111 at a time is half of the excluded volume dV.

  Next, the normal drive signal and the heating drive signal are compared. FIG. 8 is a diagram schematically showing waveforms for one cycle of the normal drive signal and the heating drive signal generated by the drive signal generation unit 54, and (a) is a diagram showing the waveform of the normal drive signal DN. FIG. 6B is a diagram illustrating a waveform of the heating drive signal DH. As shown in FIG. 8 (a), the repetition frequency f of the normal drive signal DN is set to 10 kHz, whereas as shown in FIG. 8 (b), the repetition frequency f of the heating drive signal DH is 100 kHz. Is set to Here, the case where the repetition frequency f of the heating drive signal DH is set to 100 kHz will be described as an example, but the repetition frequency f of the heating drive signal DH is preferably a frequency of 40 kHz or more in the ultrasonic region. .

  The repetition frequency f in the vicinity of 100 kHz is a frequency at which the piezoelectric element 150 can be sufficiently driven (mechanically deformed) and at the same time, the operating heat is generated with high responsiveness by driving the piezoelectric element 150 at a high speed. It is. The amplitude of the heating drive signal DH is large enough not to eject a droplet from the nozzle opening 111, for example, the amplitude VHN of the normal drive signal DN (the difference between the maximum potential VPS and the minimum potential LVS shown in FIG. 7A). ) Is set to half (50%). Here, the case where the amplitude of the heating drive signal DH is set to half of the amplitude VHN of the normal drive signal DN will be described as an example, but the amplitude of the heating drive signal DH is equal to the amplitude VHN of the normal drive signal DN. It is preferably less than half.

  Based on the drive signal generation data from the calculation control unit 52, the drive signal generation unit 54 includes the normal drive signal, the forced discharge drive signal, the heating drive signal, and the minute drive signal that are equal to or higher than one discharge cycle of the discharge head 20. A drive signal including one or more is generated. For example, a drive signal including a normal drive signal and a minute drive signal, or a drive signal including a forced ejection drive signal, a heating drive signal, and a minute drive signal is generated. The drive signal including the normal drive signal and the minute drive signal is generated when, for example, a droplet is ejected onto the substrate P, and the forced ejection drive signal, the heating drive signal, and the drive signal including the minute drive signal are nozzle openings. It is generated when 111 clogging is eliminated.

  FIG. 9 is a diagram illustrating an example of driving in which a forced ejection driving signal, a heating driving signal, and a minute driving signal are included in one ejection cycle. In the example shown in FIG. 9, one discharge cycle is divided into three periods T11 to T13, the period T11 includes the heating drive signal DH, and the period T2 includes the forced discharge drive signal DK. The period T13 includes the minute drive signal DB. When the clogging of the nozzle opening 111 of the ejection head 20 is eliminated, a drive signal including the heating drive signal DH, the forced ejection drive signal DK, and the minute drive signal DB shown in FIG. At least one of the heating drive signal DH, the forced ejection drive signal DK, and the minute drive signal DB is selected according to the waveform selection data included in the output selection data.

  Although details will be described later, at least one of a heating drive signal DH and a forced discharge drive signal DK is applied to the piezoelectric element 150 provided corresponding to the nozzle opening 111 in which the discharge failure is detected by the discharge detection device 38. It is selected and applied to the piezoelectric element 150 corresponding to the nozzle opening 111. On the other hand, the minute drive signal DB is selected for the piezoelectric element 150 provided corresponding to the nozzle opening 111 where normal ejection is performed, and is applied to the piezoelectric element 150 corresponding to the nozzle opening 111. Is done.

[Droplet ejection head control method]
Next, a method of forming a microarray on the substrate P using the droplet discharge device IJ having the above configuration will be described, and a method of controlling a droplet discharge head performed when forming the microarray will be described in detail. FIG. 10 is a flowchart illustrating an example of a method for controlling a droplet discharge head according to an embodiment of the present invention.

  When the processing is started in the flowchart shown in FIG. 10, the calculation control unit 52 determines whether or not there is a missing dot detection instruction (step S11). The dot missing detection instruction is output from the control computer 50 when the droplet discharge device IJ is turned on, or is output from the program of the arithmetic control unit 52 at the start of droplet discharge or when the substrate P is replaced. Further, when the operator of the control computer 50 instructs the control computer 50 manually, the information is output from the control computer 50. When there is no instruction for detecting missing dots (when the determination result is “NO”), the process of step S11 is performed until there is an instruction for detecting missing dots.

  On the other hand, if it is determined in step S11 that there has been a missing dot detection instruction (when the determination result is “YES”), the arithmetic control unit 52 drives the second moving device 14 to detect the ejection of the nozzle opening 111. The ejection head 20 is moved and positioned so as to be arranged above the apparatus 38 (+ Z direction). When the positioning of the ejection head 20 is completed, the arithmetic control unit 52 outputs drive signal generation data to the drive signal generation unit 54 to generate the normal drive signal DN, and outputs selection data to the switching signal generation unit 62.

  A switching signal that instructs conduction / non-conduction of the drive signal to each piezoelectric element 150 based on the selection data from the arithmetic control unit 52 is generated by the switching signal generation unit 62 and designated by the switching signal by the switch circuit 64. A normal drive signal DN is applied to the piezoelectric element 150. Thereby, droplets are sequentially ejected from the plurality of nozzle openings of the ejection head 20 to the ejection detection device 38, and the dot detection is performed in the ejection detection device 38 (step S12).

  When the dot missing detection is completed, the detection result is output to the calculation control unit 52, and the calculation control unit 52 determines whether or not there is a dot missing (step S13). When it is determined that there is no missing dot (when the determination result is “NO”), normal droplet discharge is performed (step S14). That is, the arithmetic control unit 52 controls the first moving device 12 to move the substrate P to the movement start position, and controls the second moving device 14 and the like to move the discharge head 20 to the discharge start position. Then, the drive signal generation data and the selection data are output to the drive signal generation unit 54 and the switching signal generation unit 62, respectively, and the normal drive signal DN is applied to the piezoelectric element 150 to drop the liquid onto the substrate P. Starts to discharge.

  When the discharge of the liquid droplets is started, the arithmetic control unit 52 moves the discharge head 20 and the substrate P relative to each other in the X-axis direction (scanning), and moves a predetermined width from a predetermined nozzle of the discharge head 20 onto the substrate P. Then, droplets are ejected to form a microarray on the substrate P. In the present embodiment, the ejection head 20 performs the ejection operation while moving in the + X direction with respect to the substrate P. When the first relative movement (scanning) between the ejection head 20 and the substrate P is completed, the stage ST supporting the substrate P is moved by a predetermined amount in the Y-axis direction with respect to the ejection head 20. The arithmetic control unit 52 performs the discharge operation while moving the discharge head 20 relative to the substrate P, for example, in the second relative movement (scanning) in the −X direction. By repeating this operation a plurality of times, the ejection head 20 ejects droplets under the control of the arithmetic control unit 52 to form a microarray on the substrate P.

  When the microarray is formed on the substrate P by performing the above operation, the arithmetic control unit 52 controls the first moving device 12 to move the substrate P on which the droplets are discharged to the unloading position. Then, the suction holding by the stage ST is released, and the substrate P is unloaded from the stage ST by a transfer device (not shown). Next, while the substrate P is being unloaded from the stage ST, the arithmetic control unit 52 controls the second moving device 14 to move the ejection head 20 in the X-axis direction and position it on the capping unit 22. . Further, the ejection head 20 is moved in the Z-axis direction and placed in contact with the capping unit 22 to perform capping of the ejection head 20 (step S15). When capping of the ejection head 20 is started, the counter Tc indicating the capping time is reset, and counting of the capping time is started again using the timer unit 56. With the above operation, the operation of discharging droplets onto one substrate P is completed.

  On the other hand, when it is determined in step S <b> 13 that there is a missing dot (when the determination result is “YES”), the arithmetic control unit 52 determines whether a plurality of discharge heads 20 are formed on the basis of the detection result of the discharge detection device 38. The nozzle opening 111 with missing dots is identified from the nozzle openings 111 (step S16). In parallel with this processing, the calculation control unit 52 moves and positions the ejection head 20 so that the second moving device 14 is driven and the nozzle opening 111 is arranged above the capping unit 22 (+ Z direction). I do.

  When the identification of the nozzle opening 111 having a missing dot and the movement of the ejection head 20 are completed, the arithmetic control unit 52 performs a process for eliminating the missing dot. In this process, when the forced ejection drive signal DK and the ejection head 20 are capped for a long time on the piezoelectric element 150 corresponding to the nozzle opening 111 with missing dots, the heating drive signal DH is applied, By forcibly discharging half of the excluded volume of liquid from the nozzle, clogging of the nozzle opening 111 and the like are eliminated. In order to perform this processing, the arithmetic control unit 52 generates nozzle selection data for sequentially selecting the nozzle openings 111 formed in the ejection head 20, and applies the piezoelectric element 150 corresponding to the nozzle openings 111 specified in step S16. Waveform selection data is generated so that the forced ejection drive signal DK (and the heating drive signal DH) is applied.

  Specifically, the arithmetic control unit 52 first identifies the first nozzle opening 111 from the plurality of nozzle openings 111 and generates nozzle selection data for selecting the nozzle opening 111 (step S17). A nozzle number is assigned to each nozzle opening 111 in order, and the arithmetic control unit 52 manages and identifies each nozzle opening 111 using the nozzle number. Next, the arithmetic control unit 52 determines whether or not the selected nozzle opening 111 is a nozzle opening 111 with missing dots from the identification result of step S16 (step S18).

  When it is determined that the nozzle opening 111 has a missing dot (when the determination result is “YES”), the arithmetic control unit 52 generates a drive signal for recovering the nozzle opening 111 according to the value of the counter Tc. Waveform selection data to be applied is generated (step S19). Specifically, waveform selection data for selecting a drive signal to be applied is generated according to the table shown in FIG. In addition, the ejection amount of droplets from each nozzle opening 111 is determined, and the heating time is determined when the heating drive waveform DH is used.

  FIG. 11 is a diagram illustrating an example of a table for generating a drive signal for recovering a nozzle opening having a missing dot. When the value of the counter Tc is a value indicating 5 hours or less, the calculation control unit 52 selects the forced ejection drive signal DK as the drive signal to be applied to the piezoelectric element 150 corresponding to the nozzle opening 111, and the ejection amount 10 segments are set as follows. Here, the segment refers to the number of droplets discharged to one point (one dot) on the substrate P. For example, when it is set to discharge droplets three times for one point on the substrate P (when 1 segment = 3 droplets), if the discharge amount is set to 10 segments, 1 From the nozzle openings 111, 30 droplets are ejected.

  When the value of the counter Tc is longer than 5 hours and not longer than 24 hours, the forced ejection driving signal DK is selected as a driving signal to be applied to the piezoelectric element 150 corresponding to the nozzle opening 111, and ejection is performed. Set 30 segments as quantity. Further, when the value of the counter Tc is a value that is longer than one day (24 hours) and indicates five days or less, the forced ejection drive signal DK is used as a drive signal applied to the piezoelectric element 150 corresponding to the nozzle opening 111. Select and set 100 segments as the discharge rate. As described above, in the present embodiment, the forced ejection drive signal DK is selected for the nozzle opening 111 having the ejection failure, and the ejection amount is set to increase as the value of the counter Tc indicating the capping time increases.

  Further, when the value of the counter Tc is a value longer than 5 days and not longer than 20 days, a heating drive signal DH and a forced ejection drive signal are applied as drive signals applied to the piezoelectric element 150 corresponding to the nozzle opening 111. DK is selected, the heating time is set to 20 seconds, and the discharge amount is set to 100 segments. Further, when the value of the counter Tc is a value indicating a time longer than 20 days, a heating drive signal DH and a forced ejection drive signal DK are used as drive signals applied to the piezoelectric element 150 corresponding to the nozzle opening 111. The heating time is set to 40 seconds and the discharge amount is set to 100 segments. As described above, in this embodiment, when the capping time is longer than the predetermined time (5 days), the heating drive signal DH is applied to the piezoelectric element 150 corresponding to the nozzle opening 111 in which the ejection failure has occurred. ing.

  When the process of step S19 ends, it is determined whether or not all the nozzle openings 111 have been selected (step S20). If it is determined that the selection has not ended (if the determination result is “NO”). Return to step S17 to specify the next nozzle opening 111 and create nozzle selection data for selecting the nozzle opening 111.

  On the other hand, when the arithmetic control unit 52 determines in step S18 that the selected nozzle opening 111 is the nozzle opening 111 without dot omission (when the determination result is “NO”), it corresponds to the nozzle opening 111. Waveform selection data for applying the minute drive signal DB to the piezoelectric element 150 is generated (step S21). When this process ends, it is determined whether or not all the nozzle openings 111 have been selected (step S20). When it is determined that the selection has not ended (when the determination result is “NO”), Returning to step S17, the next nozzle opening 111 is specified, and nozzle selection data for selecting this nozzle opening 111 is created. By repeating the above processing, nozzle selection data for selecting any one of the nozzle openings 111 in the order of the nozzle numbers is generated, and a waveform for applying the forced ejection drive signal DK and the heating drive signal DH or the minute drive signal BK. Selection data is generated.

  On the other hand, when it is determined in step S20 that all the nozzle openings 111 have been selected (when the determination result is “YES”), the driving integrated circuit in which the driving signal and the selection data are provided in the ejection head 20 are provided. A process for eliminating clogging and the like is performed by forcibly ejecting half of the excluded volume of liquid from the nozzle openings 111 having ejection defects (step S22).

  When this processing is started, the arithmetic control unit 52 causes the drive signal generation unit 54 to include a heating drive signal DH, a forced ejection drive signal DK, and a minute drive signal DB in one ejection cycle shown in FIG. The drive signal generation data for generating is output. When the drive signal generation data is output from the arithmetic control unit 52 to the drive signal generation unit 54, the drive signal shown in FIG. 9 is output from the drive signal generation unit 54 to the switch circuit 64.

  The arithmetic control unit 52 outputs selection data including nozzle selection data and waveform selection data to the switching signal generation unit 62. When the selection data is output from the arithmetic control unit 52 to the switching signal generation unit 62, the switching signal generation unit 62 instructs the conduction / non-conduction of the driving signal to each piezoelectric element 150, and the heating driving signal DH. A selection signal for selecting one of the forced ejection drive signal DK and the minute drive signal DB is generated.

  One of the plurality of switch circuits 64 is opened by the switching signal generated by the switching signal generation unit 62, thereby selecting one piezoelectric element 150 (nozzle opening 111) to which a drive signal is applied. . Further, any one of the heating drive signal DH, the forced ejection drive signal DK, and the minute drive signal DB shown in FIG. 9 is selected by the selection signal generated by the switching signal generation unit 62. The heating drive signal DH or the forced ejection drive signal DK is selected when the nozzle opening 111 with ejection failure is selected by the switching signal, and the minute drive signal is selected when the nozzle opening 111 without ejection failure is selected. DB is selected. Then, the selected drive signal is applied to the piezoelectric element 150 from the switch circuit 64 which is opened by the switching signal, and half of the excluded volume of liquid is forcibly discharged from the nozzle opening 111 having a defective discharge. The meniscus is vibrated slightly in the nozzle opening 111 where there is no ejection failure.

  When the capping time is longer than 5 days but not longer than 20 days, the heating drive signal DH is first selected for 20 seconds for the piezoelectric element 150 corresponding to the nozzle opening 111 having the ejection failure. As a result, the liquid in the cavity 121 communicating with the nozzle opening 111 is heated. When the heating is finished, the forced ejection drive signal DK is selected and applied to the piezoelectric element 150 corresponding to the nozzle opening 111, and the operation of forcibly ejecting the liquid of half of the excluded volume is performed. This operation is performed for 100 segments.

  When the above processing is completed, the nozzle opening 111 and the drive signal are selected based on the selection data output from the arithmetic control unit 52, and the piezoelectric element 150 corresponding to the selected nozzle opening 111 is applied. The selected drive signal is applied to forcibly discharge (in addition to heating) the liquid that is half of the excluded volume, or the meniscus is vibrated slightly. The above process is repeated by the number of nozzle openings 111 formed in the ejection head 20. When the process of step S22 is completed, the process returns to step S12 to detect the missing dot again. When there is no missing dot, normal ejection is performed (step S14), and when the missing dot is not eliminated. Steps S16 to S22 are performed.

  As described above, in the present embodiment, since the driving signal applied to the piezoelectric element 150 is changed according to the capping time of the ejection head 20, the droplet is forcibly ejected from the nozzle opening. The clogging of the nozzle opening can be eliminated with high accuracy. Further, since the clogging of the nozzle opening 111 is prevented, the number of cleanings of the discharge head 20 by the cleaning unit 24 can be reduced, so that the performance of the discharge head such as a decrease in the water repellency of the liquid is not caused. . Furthermore, since the number of cleanings is reduced, it is possible to reduce the consumption of the wiper of the cleaning device.

  Further, in this embodiment, a forced ejection drive signal DK is applied to the pressure generating element 150 corresponding to the nozzle opening 111 having a defective ejection to forcibly eject half of the excluded volume, and the nozzle having no defective ejection. For the pressure generating element 150 corresponding to the opening 111, a minute driving signal DB is applied to vibrate the meniscus without discharging a droplet. For this reason, since the liquid is not discharged as droplets from the nozzle opening 111 having no discharge failure, wasteful consumption of the liquid can be suppressed. Further, by vibrating the meniscus, liquid thickening can be suppressed, and clogging of the nozzle opening 111 can be prevented.

  Further, in the present embodiment, the liquid in the cavity 121 is heated by applying a heating drive signal DH to the pressure generating element 150 corresponding to the nozzle opening 111 having the ejection failure according to the capping time. By heating the liquid, the viscosity of the liquid in the cavity 121 can be reduced, or the solidified solid can be melted, so that the clogging of the nozzle opening can be eliminated with higher accuracy.

  In the embodiment described above, the heating time of the liquid and the discharge amount of the liquid droplets are changed according to the capping time. However, for example, the heating time and the discharge amount may be changed according to the type of liquid (for example, a difference in viscosity). Further, in the above-described embodiment, droplets are forcibly discharged from the nozzle opening 111 having a defective discharge while the discharge head 20 is positioned above the capping unit 22. However, it is not necessary to forcibly discharge droplets into the capping unit 22, and for example, a dedicated region (flushing region) for discharging droplets is provided on the stage ST, You may make it discharge a droplet compulsorily.

[Device Manufacturing Method and Electronic Equipment]
The capping device, the control method thereof, and the droplet discharge device according to the embodiment of the present invention have been described above. The droplet discharge device is a film formation device that forms a film, a wiring device that forms a wiring such as a metal wiring, or the like. It can be used as a device manufacturing apparatus for manufacturing devices such as a microlens array, a liquid crystal display device, an organic EL device, a plasma display device, and a field emission display (FED).

  Since the clogging of the nozzle opening 111 is eliminated using the above-described liquid droplet ejection device, and a pattern is formed by ejecting liquid droplets onto the substrate P using the ejection head 20 that has finished such processing, Wasteful consumption of the solvent can be suppressed, and the droplet discharge time for forming the pattern can be lengthened. As a result, the manufacturing cost of the device can be reduced and the throughput can be improved.

  Devices such as the above-described liquid crystal device, organic EL device, plasma display device, and FED are provided in electronic devices such as notebook computers and mobile phones. However, the electronic device is not limited to the above-described notebook computer and mobile phone, and can be applied to various electronic devices. For example, LCD projectors, multimedia-compatible personal computers (PCs) and engineering workstations (EWS), pagers, word processors, TVs, viewfinder type or monitor direct view type video tape recorders, electronic notebooks, electronic desk calculators, car navigation systems The present invention can be applied to electronic devices such as a device, a POS terminal, and a device provided with a touch panel.

1 is a perspective view showing a schematic configuration of a droplet discharge device according to an embodiment of the present invention. 3 is an exploded perspective view of the ejection head 20. FIG. 3 is a perspective view showing a part of the main part of the ejection head 20. FIG. It is a figure which shows the structure of the capping unit. It is a block diagram which shows the electrical function structure of the droplet discharge apparatus by one Embodiment of this invention. It is a figure which shows typically the waveform for 1 period of the normal drive signal produced | generated by the drive signal production | generation part 54, and operation | movement of an ejection head. It is a figure for demonstrating a normal drive signal, a forced discharge drive signal, and an exclusion volume. It is a figure which shows typically the waveform for 1 period of the normal drive signal and heating drive signal which are produced | generated by the drive signal production | generation part 54. FIG. It is a figure which shows an example of the drive in which a forced discharge drive signal, a heating drive signal, and a micro drive signal are contained within one discharge period. 4 is a flowchart illustrating an example of a method for controlling a droplet discharge head according to an embodiment of the present invention. It is a figure which shows an example of the table for producing | generating the drive signal which recovers the nozzle opening with a missing dot.

Explanation of symbols

20 …… Discharge head (droplet discharge head)
38 …… Discharge detection device (detection device)
52 …… Calculation control unit (control means)
54... Drive signal generator (drive signal generator)
56 …… Timer section (time measuring means)
62 ...... Switching signal generator (control means)
64 …… Switch circuit (control means)
111 …… Nozzle opening 121 …… Cavity 150 …… Piezoelectric element (pressure generating element)
DB …… Small drive signal DH …… Heating drive signal DK …… Forced discharge drive signal IJ …… Droplet discharge device P …… Substrate (work)

Claims (18)

A cavity for storing a predetermined liquid; a pressure generating element for generating a pressure in the cavity according to an applied drive signal; and a nozzle opening for discharging the liquid pressurized by the pressure generating element as a droplet A method of controlling a droplet discharge head comprising:
A time measuring step for measuring a time when the nozzle opening is sealed;
And a control step for controlling to forcibly eject the droplet from the nozzle opening by changing a drive signal applied to the pressure generating element in accordance with a timing result of the timing step. Discharge head control method.   The drive signal applied to the pressure generating element in the control step is forcibly forcing a half of the excluded volume of the liquid that can be excluded from the cavity by pressurization of the pressure generating element as a droplet from the nozzle opening. The method of controlling a droplet discharge head according to claim 1, further comprising an ejection drive signal.   3. The method of controlling a droplet discharge head according to claim 2, wherein the drive signal applied to the pressure generating element in the control step includes a heating drive signal for heating the liquid in the cavity.   4. The droplet according to claim 3, wherein the drive signal applied to the pressure generating element in the control step includes a minute drive signal that generates a minute pressure that does not cause the droplet to be ejected from the nozzle opening. Discharge head control method. Detecting the presence or absence of ejection of the droplet from each of the nozzle openings,
The method of controlling a droplet discharge head according to claim 4, wherein the control step performs control to change a type of the drive signal applied to the pressure generating element according to a detection result of the detection step. The control step generates a drive signal including the forced ejection drive signal, the heating drive signal, and the minute drive signal in one ejection cycle;
A selection step of selecting one or two of the forced ejection drive signal, the heating drive signal, and the minute drive signal in accordance with the detection result of the detection step and applying the selected one to the pressure generating element. The method of controlling a droplet discharge head according to claim 5.   In the selection step, the forced ejection drive signal is selected and applied to the pressure generating element corresponding to the nozzle opening that is detected in the detection step that the droplet is not ejected. The method for controlling a droplet discharge head according to claim 6.   8. The method of controlling a droplet discharge head according to claim 7, wherein the selection step selects the heating drive signal in addition to the forced discharge drive signal.   In the selecting step, the minute driving signal is selected and applied to the pressure generating element corresponding to the nozzle opening that is detected as having ejected the droplet in the detecting step. The method of controlling a droplet discharge head according to claim 7 or 8.   The said control step performs control which increases / decreases the frequency | count of forcibly discharging the said droplet from the said nozzle opening according to the timing result of the said timing step, The any one of Claim 1-9 characterized by the above-mentioned. The method for controlling a droplet discharge head according to the item. A cavity for storing a predetermined liquid; a pressure generating element for generating a pressure in the cavity according to an applied drive signal; and a nozzle opening for discharging the liquid pressurized by the pressure generating element as a droplet And a capping device having a sealing portion that seals the nozzle opening of the droplet discharge head,
Clocking means for timing the time when the nozzle opening of the droplet discharge head is sealed in the sealing portion;
Drive signal generating means for generating a drive signal including a plurality of different drive signals in one ejection cycle;
Control for forcibly ejecting the droplet from the nozzle opening by changing the drive signal applied to the pressure generating element among the drive signals generated by the drive signal generating means according to the time measurement result of the time measuring means. And a control means for performing the operation. The drive signal generating means forcibly discharges a half of the excluded volume of the liquid that can be excluded from the cavity by pressurization of the pressure generating element as a droplet from the nozzle opening, and
A heating drive signal for heating the liquid in the cavity;
The droplet ejection device according to claim 11, further comprising: a minute drive signal that generates a minute pressure that does not cause the droplet to be ejected from the nozzle opening. A detection device for detecting the presence or absence of ejection of the droplet from each of the nozzle openings,
The control unit selects one or two of the forced ejection drive signal, the heating drive signal, and the minute drive signal according to the detection result of the detection device and applies the selected one or two to the pressure generating element. 13. The droplet discharge device according to claim 12, wherein control is performed.   The control means selects and applies the forced ejection drive signal to the pressure generating element corresponding to the nozzle opening that is detected by the detection device as not ejecting the droplet. The droplet discharge device according to claim 13.   15. The droplet discharge apparatus according to claim 14, wherein the control unit selects the heating drive signal in addition to the forced discharge drive signal.   The control means selects and applies the minute driving signal to the pressure generating element corresponding to the nozzle opening detected when the droplet is ejected by the detection device. The droplet discharge device according to claim 14 or 15.   17. The control unit according to claim 11, wherein the control unit performs control to increase or decrease the number of times that the droplet is forcibly ejected from the nozzle opening according to a timing result of the timing unit. The droplet discharge device according to item. A method for manufacturing a device including a workpiece having a pattern having functionality at a predetermined location,
The method for controlling the droplet discharge device according to any one of claims 1 to 10, or the droplet using the droplet discharge device according to any one of claims 11 to 17. A preliminary discharge step of discharging the predetermined liquid from the nozzle opening provided in the discharge head;
Using the droplet discharge head that has undergone the preliminary discharge step to discharge the droplet onto the workpiece to form the pattern.

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