CN117719257A

CN117719257A - Liquid ejecting apparatus, control method thereof, substrate processing apparatus, and article manufacturing method

Info

Publication number: CN117719257A
Application number: CN202311180935.8A
Authority: CN
Inventors: 山本哲也
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2022-09-16
Filing date: 2023-09-12
Publication date: 2024-03-19

Abstract

The invention provides a liquid ejecting apparatus, a control method thereof, a substrate processing apparatus and a method for manufacturing an article, which are advantageous in reducing the time required for recovery processing of ejection abnormality of liquid in the liquid ejecting apparatus and the amount of liquid used. The liquid ejecting apparatus includes: a plurality of ejection elements ejecting liquid according to the drive signal; and a control unit that controls supply of the drive signal to each of the plurality of ejection elements, wherein when a first ejection element and a second ejection element having a degree of ejection abnormality lower than that of the first ejection element are determined from among the plurality of ejection elements as ejection elements having ejection abnormality, the control unit supplies a first drive signal of a first frequency to the first ejection element without supplying the first drive signal to the second ejection element and supplies a second drive signal of a second frequency lower than the first drive signal to the second ejection element in recovery processing for reducing the ejection abnormality of the plurality of ejection elements.

Description

Liquid ejecting apparatus, control method thereof, substrate processing apparatus, and article manufacturing method

Technical Field

The present invention relates to a liquid ejecting apparatus, a control method of the liquid ejecting apparatus, a substrate processing apparatus, and a method of manufacturing an article.

Background

In recent years, in manufacturing various functional elements, an attempt has been made to apply a material of the functional element to a substrate using an inkjet device to form a pattern (patterning). Patterning using an inkjet device has the following advantages: since patterning as needed is possible, the material is used efficiently, and since it is a non-vacuum process, the manufacturing apparatus becomes relatively small, and a large area can be coated at high speed.

In the inkjet device described above, problems (ejection abnormality) such as ejection failure and quality disturbance may occur during formation or standby of the dot pattern due to foreign matter adhering to the inside of the flow path and in the vicinity of the nozzle opening, thickening of ink, sedimentation of ink components, electrophoresis, and the like. Patent document 1 discloses a technique of performing a medium-volume preliminary ejection and a large-volume preliminary ejection from the start of a small-volume preliminary ejection until recovery can be confirmed. Patent document 2 discloses a technique of discharging ink while increasing or decreasing the driving frequency of a recording head in order to remove bubbles in the recording head. Patent document 3 discloses the following: the cause of the ejection abnormality of the liquid droplet ejection head is determined, and any one of the flushing process, the wiping process, and the pump suction process is selected as the recovery process of the liquid droplet ejection head based on the determined cause of the ejection abnormality.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2012-201076

Patent document 2: japanese patent No. 2659954

Patent document 3: japanese patent No. 4269731

Disclosure of Invention

Problems to be solved by the invention

However, in the recovery method described in patent document 1, recovery is performed only by changing the preliminary ejection amount, and sometimes an unrecoverable nozzle may be generated. In the structure described in patent document 2, since preliminary ejection is performed on all the nozzles while continuously changing the driving frequency, the recovery process takes a long time, and the consumption amount of ink (liquid) increases. In the configuration described in patent document 3, only any one of the flushing process, the wiping process, and the pump suction process is selected as the recovery process according to the cause of the ejection abnormality of the droplet ejection head. Therefore, depending on the degree of ejection abnormality, the consumption amount of ink (liquid) used in the selected recovery process may become large.

Accordingly, an object of the present invention is to provide a technique that is advantageous in reducing the time required for recovery processing of ejection abnormalities of a liquid in a liquid ejection device and the amount of liquid used.

Means for solving the problems

In order to achieve the above object, a liquid discharge device according to an aspect of the present invention includes: a plurality of ejection elements ejecting liquid according to the drive signal; and a control unit that controls supply of the drive signal to each of the plurality of ejection elements, wherein when a first ejection element and a second ejection element having a degree of ejection abnormality lower than that of the first ejection element are determined from among the plurality of ejection elements as ejection elements having ejection abnormality, the control unit supplies a first drive signal of a first frequency to the first ejection element without supplying the first drive signal to the second ejection element and supplies a second drive signal of a second frequency lower than the first drive signal to the second ejection element in recovery processing for reducing the ejection abnormality of the plurality of ejection elements.

In order to achieve the above object, a control method according to an aspect of the present invention is a control method of a liquid discharge apparatus including a plurality of discharge elements for discharging liquid according to a drive signal, the control method including: a determining step of determining a discharge element having a discharge abnormality from among the plurality of discharge elements; and a recovery processing step of reducing ejection anomalies of the plurality of ejection elements, wherein in the determination step, when a first ejection element and a second ejection element having a degree of ejection anomalies lower than that of the first ejection element are determined as ejection elements having ejection anomalies, a first step of supplying a first drive signal of a first frequency to the first ejection element without supplying a second drive signal of a first frequency to the second ejection element, and a second step of supplying a second drive signal of a second frequency lower than the first frequency to at least the second ejection element are performed.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, for example, a technique advantageous in reducing the time required for recovery processing of ejection abnormality of liquid in a liquid ejection device and the amount of liquid used can be provided.

Further objects and other aspects of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is a diagram showing a structure of an inkjet device.

Fig. 2 is a diagram showing an example of a control structure of one ejection head.

Fig. 3 is a diagram showing an example of a circuit configuration of each nozzle.

Fig. 4 is a diagram illustrating a relationship between a residual signal waveform and an abnormal ejection state.

Fig. 5 is a diagram illustrating a method of determining an abnormal ejection state of a nozzle using a residual signal waveform.

Fig. 6 is a diagram illustrating recovery processing based on preliminary ejection.

Fig. 7 is a flowchart showing the recovery process of embodiment 1.

Fig. 8A is a flowchart showing the recovery process of embodiment 2.

Fig. 8B is a flowchart showing the recovery process of embodiment 2.

Fig. 9 is a diagram showing a residual signal waveform when ejection abnormality occurs due to mixing of bubbles.

Fig. 10 is a flowchart showing an operation sequence of the inkjet device.

Fig. 11 is a schematic diagram showing an example of coating of a material of a functional element.

Detailed Description

The embodiments are described in detail below with reference to the drawings. The following embodiments are not limited to the embodiments described in the claims. Although the embodiments have been described with respect to a plurality of features, the plurality of features are not limited to all the features necessary for the technical means, and may be combined arbitrarily. In the drawings, the same or similar structures are denoted by the same reference numerals, and redundant description thereof is omitted.

The structure and operation principle of the inkjet device 1 (substrate processing apparatus) will be described with reference to fig. 1. The ink jet device 1, which can function as a substrate processing apparatus for processing a panel for a display or a substrate for a semiconductor, forms a pattern or a film by applying a material of a functional element to the substrate. In the specification and drawings, as shown in fig. 1, directions are indicated in an XYZ coordinate system in which a plane parallel to a plane on which the substrate 2 is disposed is an XY plane. The inkjet device 1 has, for example, a substrate stage 3 that holds and moves a substrate 2 of a display panel. The substrate 2 may be appropriately selected from a glass substrate, a plastic substrate, and the like, according to the object product to be manufactured. The substrate 2 is typically a plate-shaped member, but is not limited to a specific shape as long as it can function as a substrate. For example, the substrate 2 may be a deformable film or a circular substrate. The substrate 2 on the substrate stage 3 has a pixel region 201 in which a plurality of display pixels are arranged for applying ink, and an evaluation region 202 in which ink is experimentally ejected for evaluating the state of the ink. The evaluation region 202 may be provided in a specific region of the substrate stage 3. In the present specification, "ink" refers to a liquid for forming a pattern or a film on the substrate 2. In the present specification, the components of the ink are not particularly limited, and for example, a liquid including a solute and a solvent for forming an organic film can be used.

The inkjet device 1 includes: a discharge head 5 (liquid discharge device) capable of discharging ink droplets 4 toward a predetermined position of the substrate 2; and an ink supply system 6 for supplying ink from an ink cartridge 7 storing ink to the ejection head 5. The ejection head 5 includes a plurality of nozzles 19 (ejection elements) that eject ink (liquid) in accordance with the drive signal. The ink cartridge 7 may be disposed inside the ink jet device 1 or may be disposed outside the ink jet device 1. The inkjet device 1 may further include a recovery unit 8, and the recovery unit 8 may recover ejection characteristics by performing cleaning treatment or the like on the ejection nozzles of the ejection head 5.

When the substrate 2 is mounted on the substrate stage 3, a placement error may occur. In addition, since the substrate 2 is subjected to various manufacturing processes, shape deformation may occur on the substrate 2 in the XY directions. Therefore, the inkjet device 1 may be provided with an alignment viewer 9 that measures the position of the substrate 2 and the deformation amount of the substrate 2. In order to perform alignment measurement on the entire surface of the substrate 2, the alignment viewer 9 and the substrate stage 3 are driven relatively in the XY direction. I.e. the alignment viewer 9 and/or the substrate stage 3 are driven in XY directions. The substrate 2 mounted on the substrate stage 3 has a thickness variation. Therefore, when the ink is ejected by the ejection head 5 while scanning the substrate stage 3 in the Y direction, there is a possibility that the landing position (adhering position) of the ink droplet on the substrate 2 may be deviated due to the thickness deviation of the substrate 2. Therefore, the inkjet device 1 may further include a height sensor 10 that measures the position (height) of the substrate 2 in the Z direction. In order to perform height measurement on the entire surface of the substrate 2, the height sensor 10 and the substrate stage 3 are driven relatively in the XY directions. That is, the height sensor 10 and/or the substrate stage 3 are driven in the XY directions.

The main control unit 11 controls the respective units of the inkjet device 1 to collectively pattern onto the substrate 2. The main control unit 11 may be configured by a computer having a processor such as a CPU (Central Processing Unit: central processing unit) and a storage unit such as a memory. The main control unit 11 may be configured by, for example, PLD (abbreviation of Programmable Logic Device) such as FPGA (abbreviation of Field Programmable Gate Array), ASIC (abbreviation of Application Specific Integrated Circuit), a general-purpose computer in which a program is incorporated, or a combination of all or a part of them.

In one example, a plurality of ejection heads 5 are arranged in the X-direction and the Y-direction, and by controlling the ejection of ink droplets from each of the ejection heads 5, a desired distribution of ink can be applied to the pixel region 201 on the substrate 2. Fig. 2 shows an example of a control structure of the ejection head 5. The ejection head 5 may be provided with a plurality of nozzles 19. The plurality of nozzles 19 each constitute a discharge element including a piezoelectric element P (discharge energy generating element, piezoelectric actuator). The plurality of nozzles 19 are connected to the driver D that drives the piezoelectric element P via flexible cables F, respectively. The driver D is connected to the ejection control unit C (control unit).

The ejection control unit C individually controls the ejection of ink droplets from the respective nozzles 19 by controlling the supply of a drive signal to each of the plurality of nozzles 19 (piezoelectric elements P) via the driver D. The ejection control unit C may be configured by a computer including a processor such as a CPU (Central Processing Unit: central processing unit) and a storage unit such as a memory. In the recovery process for recovering the abnormal ejection nozzle from among the plurality of nozzles 19, the ejection control unit C supplies a drive signal for recovering the abnormal ejection nozzle to each nozzle 19 (piezoelectric element P) via the driver D. Specifically, the ejection control unit C transmits a recovery processing instruction for recovering the ejection abnormal nozzle to the driver D. The driver D that has received the recovery processing instruction generates a drive signal (e.g., voltage) corresponding to the recovery processing instruction and supplies the drive signal to the piezoelectric element P that ejects the abnormal nozzle, thereby driving the piezoelectric element P that ejects the abnormal nozzle to execute the recovery processing. The recovery process may be understood as a process of reducing ejection abnormalities in the plurality of nozzles 19. The function of the ejection control unit C may be realized by the main control unit 11.

In each of the plurality of nozzles 19, problems (ejection abnormality) such as ejection failure or quality disturbance may occur due to foreign matters adhering to the inside of the flow path or the vicinity of the nozzle opening, thickening of ink, sedimentation of ink components, electrophoresis, or the like during formation or standby of the dot pattern on the substrate. Such a problem (ejection abnormality) occurs due to the combined action of various factors such as ejection time, flow path shape, distance from the electrode, standby time without ejection, and the like. The degree of ejection abnormality may be different in each nozzle.

The recovery unit 8 is used for recovery processing from ejection of foam or nozzle clogging of a strong level that cannot be recovered by preliminary ejection. However, the recovery process using the recovery unit 8 takes a long time, and the amount of ink used in the recovery process becomes very large. Therefore, the recovery process using the recovery unit 8 is performed only at the timing set as the regular maintenance. In normal operation, preliminary ejection from the plurality of nozzles 19 is appropriately performed in the preliminary ejection area 20, and the abnormal ejection nozzles are returned to a normal state.

The degree of ejection abnormality (ejection abnormality state) of each nozzle 19 can be confirmed using a correlation signal (residual signal waveform) measured after a specific pressure is generated in the piezoelectric element P. Specifically, the ejection control unit C applies a specific drive signal (for example, a pulse signal) to the piezoelectric element P via the driver D to operate the piezoelectric element P. A specific pressure wave is generated in the piezoelectric element P in response to the operation of the piezoelectric element P. If the piezoelectric element is normal, ink is dropped from the nozzle by the pressure wave. At this time, the piezoelectric element P is deformed by the pressure wave generated in the piezoelectric element P, and an electrical signal corresponding to the deformation remains (is generated). The electrical signal is referred to as the "residual signal". The ejection control unit C can detect the residual signal and measure (determine) the degree of ejection abnormality based on the waveform of the detected residual signal.

Fig. 3 shows an example of a circuit configuration of each nozzle 19 in the present embodiment. In the configuration example of fig. 3, a circuit configuration example of one nozzle 19 is shown, but the same circuit configuration may be applied to each of the plurality of nozzles 19. As shown in fig. 3, each nozzle 19 may include a piezoelectric element P, a signal generating section 21, a switching section 22, and a measuring section 23.

The signal generating unit 21 is, for example, a driver D, and generates a driving signal of the piezoelectric element P in accordance with a command supplied from the ejection control unit C. In the recovery process, since the recovery process command is supplied from the ejection control section C to the signal generation section 21, the signal generation section 21 generates a drive signal corresponding to the recovery process command. The driving signal generated by the signal generating section 21 is supplied to the piezoelectric element P via the switching section 22. Thereby, the piezoelectric element P can eject ink in accordance with the drive signal supplied from the signal generating section 21. The residual signal generated in the piezoelectric element P by the supply of the drive signal is supplied to the measurement unit 23 via the switching unit 22.

The switching unit 22 is a mechanism for switching between supply of a driving signal from the signal generating unit 21 to the piezoelectric element P and supply of a residual signal from the piezoelectric element P to the measuring unit 23. In the configuration example of fig. 3, the switching unit 22 is configured as a switching element, but may be configured as a circulator that guides the driving signal from the signal generating unit 21 to the piezoelectric element P and guides the residual signal from the piezoelectric element P to the measuring unit 23, for example.

The measurement unit 23 is a mechanism that detects a residual signal supplied from the piezoelectric element P via the switching unit 22, and measures an index indicating the degree of ejection abnormality (hereinafter, sometimes referred to as an ejection abnormality index) based on the detected residual signal. In the configuration example of fig. 3, the measurement unit 23 may include an amplifier 23a and a processing unit 23b (processor). The amplifier 23a amplifies the residual signal supplied from the piezoelectric element P via the switching section 22, and supplies the amplified residual signal to the processing section 23b. The processing unit 23b measures the ejection abnormality index of the nozzle 19 (piezoelectric element P) based on the period of the waveform of the residual signal supplied from the amplifier 23a or the initial peak position in the waveform of the residual signal. For example, the processing unit 23b can measure, as the ejection abnormality index, a difference between the period of the waveform of the residual signal supplied from the amplifier 23a (piezoelectric element P) and the reference waveform or a difference between the first peak positions. The reference waveform is a waveform of a residual signal to be obtained from the piezoelectric element P that operates normally, and is obtained in advance by an experiment, simulation, or the like. In the configuration example of fig. 3, the measurement unit 23 is configured to measure the ejection abnormality index for 1 nozzle 19, but may be understood as a unit that measures the ejection abnormality index for each of the plurality of nozzles 19. The processing unit 23b of the measuring unit 23 may be configured as a part of the ejection control unit C.

Fig. 4 (a) shows an example of a residual signal waveform. The horizontal axis represents time, and the vertical axis represents potential. The residual signal waveform shown in fig. 4 a is a reference residual signal waveform (reference waveform) indicating the state of the nozzle capable of stable ejection, and if the equivalent residual signal waveform is obtained, it is determined that the nozzle is in a normal state. If the abnormal ejection state of the nozzle 19 progresses and the degree of abnormal ejection becomes high, the waveform changes as follows.

If the abnormal ejection state of the nozzle progresses (that is, if the degree of abnormal ejection increases), the residual signal waveform changes from the solid line state to the broken line state as shown in fig. 4 b. Specifically, the first peak position is shifted from T0 to T1 and T2, and the period of the residual signal waveform is also prolonged. As the ejection abnormal state progresses, the residual signal waveform moves from the broken line 1 to the broken line 2. The measurement unit 23 can measure the difference between the periods of the residual signal waveform (for example, the broken line 1 and the broken line 2) detected from the piezoelectric element P and the reference waveform (for example, the solid line 1) or the difference between the initial peak positions as the ejection abnormality index. The nozzle in the abnormal ejection state (abnormal ejection nozzle) returns to the normal state by performing preliminary ejection at a frequency corresponding to the degree of abnormal ejection. That is, the residual signal waveform returns to the original reference waveform (solid line waveform) of fig. 4 (a).

Recovery processing by preliminary ejection will be described with reference to fig. 5 (a) to (d). Fig. 5 (a) shows a residual signal waveform detected by the measuring section 23 for each of the 5 nozzles a to E. Since the ejection abnormality state (i.e., the degree of ejection abnormality) differs from one nozzle to another, the residual signal waveforms also differ from one nozzle a to another in the nozzles a to E as shown in fig. 5 (a). The recovery process is a process for recovering from a discharge abnormal state different for each nozzle as shown in fig. 5 (a) to a normal state (reference waveform) as shown in fig. 4 (a) by preliminary discharge. The recovery process is performed by determining a preliminary ejection frequency suitable for the abnormal ejection state of the nozzle and applying a drive signal (for example, a pulse signal) of the preliminary ejection frequency to the nozzle. By performing such recovery processing, the nozzle from which the discharge abnormality is detected can be recovered. In the present embodiment, the preliminary ejection frequency applied sequentially to the same nozzle group is reduced from the preliminary ejection frequency suitable for the nozzle having the greatest degree of ejection failure in the recovery process, but the present invention is not limited to this. For example, the preliminary ejection frequency to be sequentially applied to the same nozzle group may be increased from the preliminary ejection frequency suitable for the nozzle with the smallest degree of ejection abnormality.

In the case of the present embodiment, the ejection control unit C classifies the degree of ejection abnormality (ejection abnormality state) into a plurality of groups based on the measurement result of the measurement unit 23, and identifies the nozzles belonging to each group from among the plurality of nozzles. Specifically, the ejection control unit C determines, from among the plurality of nozzles 19, 1 or more first nozzles (first ejection elements) whose ejection abnormality index is located in the first range and 1 or more second nozzles (second ejection elements) whose ejection abnormality index is located in the second range. Hereinafter, one or more first nozzles are referred to as a first nozzle group (first ejection element group), and one or more second nozzles are referred to as a second nozzle group (second ejection element group). Here, the first nozzle group is a nozzle group having a higher degree of ejection abnormality than the second nozzle group. That is, the first range is a range in which the ejection abnormality index is higher than the second range, and the lower limit value of the ejection abnormality index in the first range can be set higher than the upper limit value of the ejection abnormality index in the second range. In the following, examples of 3 abnormal nozzle groups, i.e., a heavy abnormal nozzle group having a heavy degree of ejection abnormality, a medium abnormal nozzle group having a medium degree of ejection abnormality, and a light abnormal nozzle group having a light degree of ejection abnormality, are specified from among the plurality of nozzles 19. In this case, if the severely abnormal nozzle group is taken as the first nozzle group, the moderately abnormal nozzle group may belong to the second nozzle group. On the other hand, if the moderately abnormal nozzle group is taken as the first nozzle group, the moderately abnormal nozzle group may belong to the second nozzle group.

In one example, as shown in fig. 5 (a), when there are a plurality of nozzles having different degrees of ejection abnormality, the ejection control unit C classifies the degrees of ejection abnormality into 3 groups (heavy, medium, light) as shown in fig. 5 (b) to (d). The ejection controller C determines a heavy abnormal nozzle group, a medium abnormal nozzle group, and a light abnormal nozzle group from the plurality of nozzles 19 based on the ejection abnormality index measured for each nozzle by the measuring unit 23. In the following, an example will be described in which the initial peak position in the residual signal waveform is used as an ejection abnormality index.

For example, as shown in fig. 5 (d), since the first peak position in the residual signal waveform of the nozzle E is located in the region I including T2, the ejection control section C determines the nozzle E as a heavy abnormal nozzle group. As shown in fig. 5 (C), since the initial peak position in the residual signal waveform of the nozzle D is located within the region II including T1, the ejection controller C determines the nozzle D as a moderate abnormal nozzle group. Further, as shown in fig. 5 (B), since the first peak position in the residual signal waveform of the nozzles B to C is located in the region III including T0, the ejection controller C determines the nozzles B to C as a slightly abnormal nozzle group. Since the nozzle a is in a normal state, the residual signal waveform of the nozzle a shown in fig. 5 (b) is the same as the reference waveform of fig. 4 (a).

Then, the ejection control unit C performs preliminary ejection via the driver D using a drive signal of a frequency suitable for the degree of ejection abnormality. That is, the ejection control unit C controls the driver D to apply a drive signal (for example, a pulse signal) having a frequency suitable for the degree of ejection abnormality to the nozzle to perform preliminary ejection. In the case of the present embodiment, first, preliminary ejection based on the supply of the first drive signal at the first frequency is performed to the first nozzle group. At this time, preliminary ejection based on the supply of the first drive signal is not performed for the second nozzle group. In order to reduce the degree of ejection abnormality of the first nozzle group, the first frequency of the first drive signal is set in advance by experiment, simulation, or the like. In the first nozzle group in which preliminary ejection based on the supply of the first drive signal is performed, the degree of ejection abnormality can be reduced so that the ejection abnormality index moves to be within the second range. That is, in the first nozzle group in which preliminary ejection based on the supply of the first drive signal is performed, the degree of ejection abnormality can be the same as that of the second nozzle group. Then, preliminary ejection based on supply of a second drive signal at a second frequency lower than the first frequency is performed to both the first nozzle group and the second nozzle group. In order to reduce the degree of ejection abnormality of the second nozzle group, the second frequency of the second drive signal is set in advance by experiment, simulation, or the like.

In the example of fig. 5, preliminary ejection using a high-frequency drive signal is suitable for a heavy abnormal nozzle group in which the initial peak position of the residual signal waveform is located in the region I. For a moderately abnormal nozzle group in which the initial peak position of the residual signal waveform is located in the region II, preliminary ejection using a drive signal of a medium frequency is suitable. For a slightly abnormal nozzle group in which the initial peak position of the residual signal waveform is located in the region III, preliminary ejection using a low-frequency drive signal is suitable. In one example, the high frequency means a frequency in the range of 10kHz to 50 kHz. The medium frequency is a frequency in the range of 1kHz to 10 kHz. The low frequency means a frequency in the range of 100Hz to 1 kHz.

Here, if the severely abnormal nozzle group is the first nozzle group, the high-frequency drive signal supplied to the severely abnormal nozzle group corresponds to the first drive signal of the first frequency. In this case, the moderately abnormal nozzle group corresponds to the second nozzle group, and the drive signal of the intermediate frequency supplied to the moderately abnormal nozzle group corresponds to the second drive signal of the second frequency. On the other hand, if the moderately abnormal nozzle group is the first nozzle group, the drive signal of the intermediate frequency supplied to the moderately abnormal nozzle group corresponds to the first drive signal of the first frequency. In this case, the mild abnormal nozzle group corresponds to the second nozzle group, and the low-frequency drive signal supplied to the mild abnormal nozzle group corresponds to the second drive signal of the second frequency.

Fig. 6 (a) to (d) are diagrams for explaining steps (processes) for recovering the nozzles E belonging to the severely abnormal nozzle group. Fig. 6 (a) shows the same residual signal waveform as fig. 5 (d). As shown in fig. 6 a, since the first peak position in the residual signal waveform of the nozzle E is located in the region I, first, preliminary ejection using a high-frequency drive signal (hereinafter, sometimes referred to as high-frequency preliminary ejection) is performed. By performing the high-frequency preliminary ejection, as shown in fig. 6 (b), the period of the residual signal waveform of the nozzle E becomes short, and the initial peak position advances and moves into the region II. Then, in correspondence with the first peak position moving to the region II, preliminary ejection using a drive signal of an intermediate frequency (hereinafter, sometimes referred to as intermediate frequency preliminary ejection) is performed. By performing this intermediate frequency preliminary ejection, as shown in fig. 6 (c), the period of the residual signal waveform of the nozzle E is further shortened, and with this, the initial peak position is further advanced, and the nozzle E moves to the region III. Then, in correspondence with the first shift of the peak position to the region III, preliminary ejection using a low-frequency drive signal (hereinafter, sometimes referred to as low-frequency preliminary ejection) is performed. By performing this low-frequency preliminary ejection, as shown in fig. 6 (d), the residual signal waveform of the nozzle E returns to the reference waveform. That is, the ejection abnormality of the nozzle E can be reduced (recovered, eliminated).

Here, in order to obtain the same recovery effect even for nozzles having different degrees of ejection abnormality from the nozzle E, the residual signal waveform of each nozzle may be analyzed, how often the preliminary ejection is performed may be determined for each nozzle, and the preliminary ejection may be performed based on the determination result. For example, the high-frequency preliminary ejection is not performed, but only the medium-frequency preliminary ejection and the low-frequency preliminary ejection are performed for the nozzle D. This makes it possible to set the residual signal waveform of the nozzle D to the reference waveform. That is, the discharge abnormality of the nozzle D can be reduced (recovered and eliminated). In addition, since the high-frequency preliminary ejection is not performed for the nozzles D, the time required for the recovery process of the entire plurality of nozzles and the ink usage amount can be reduced. Similarly, the nozzles B to C are not subjected to the high-frequency preliminary ejection and the intermediate-frequency preliminary ejection, but are subjected to the low-frequency preliminary ejection. This makes it possible to set the residual signal waveforms of the nozzles B to C to the reference waveforms. That is, the discharge abnormality of the nozzles B to C can be reduced (recovered and eliminated). In addition, since the high-frequency preliminary ejection and the intermediate-frequency preliminary ejection are not performed for the nozzles B to C, the time and the ink usage amount required for the recovery process of the entire plurality of nozzles can be reduced. In the recovery processing, it is preferable in terms of efficiency to group nozzles having a degree of ejection abnormality close to each other and to recover ejection abnormality sequentially from a group having a heavy ejection abnormality, using a result obtained by analyzing a residual signal waveform of each nozzle.

Example 1 of recovery processing

Next, example 1 of the recovery process in the present embodiment will be described. Fig. 7 is a flowchart showing the restoration process of example 1 of the present embodiment. Each step of the flowchart of fig. 7 can be executed by the ejection control unit C, but may be executed by the main control unit 11.

In step S101, the ejection control unit C acquires a residual signal waveform for each of the plurality of nozzles 19. For example, the discharge control unit C applies a specific drive signal (for example, a pulse signal) to the piezoelectric element P by the driver D for each of the plurality of nozzles 19, generates a specific pressure wave in the piezoelectric element P, and detects a residual signal remaining in the piezoelectric element P by the measuring unit 23. Thereby, the ejection control unit C can acquire the residual signal waveform for each of the plurality of nozzles 19.

In step S102, the ejection control unit C determines whether or not each of the plurality of nozzles 19 is an abnormal ejection nozzle. The determination as to whether or not the abnormal ejection nozzle is an abnormal ejection nozzle may be made based on the period (e.g., initial peak position) of the residual signal waveform obtained in step S101. For example, as described above, the ejection control unit C determines the nozzle 19 having the period of the residual signal waveform obtained in step S101 different from the reference waveform as an abnormal ejection nozzle. The flow proceeds to step S103 for the nozzle 19 determined to be the ejection abnormal nozzle, and ends for the nozzle 19 determined not to be the ejection abnormal nozzle (normal nozzle).

In step S103, the ejection control unit C obtains a preliminary ejection frequency for performing preliminary ejection of the nozzle 19. In the case of the present embodiment, the preliminary ejection frequency includes a frequency (high frequency) suitable for preliminary ejection of a severely abnormal nozzle group, a frequency (medium frequency) suitable for preliminary ejection of a moderately abnormal nozzle group, and a frequency (low frequency) suitable for preliminary ejection of a lightly abnormal nozzle group. These preliminary ejection frequencies may be set in advance by experiments, simulations, or the like.

In step S104, the ejection control unit C groups the nozzles 19 determined to be the ejection abnormal nozzles in step S102 according to the degree of ejection abnormality, and identifies a heavy abnormal nozzle group, a medium abnormal nozzle group, and a light abnormal nozzle group. Specifically, as described above, the ejection control section C determines, as the heavy abnormal nozzle group, an abnormal nozzle whose initial peak position of the residual signal waveform is located in the region I, based on the residual signal waveform obtained in step S101. Similarly, the abnormal nozzle whose initial peak position is located in the region II of the residual signal waveform is determined as a moderate abnormal nozzle group, and the abnormal nozzle whose initial peak position is located in the region III of the residual signal waveform is determined as a mild abnormal nozzle group.

In step S105, the ejection control unit C performs high-frequency preliminary ejection. The high-frequency preliminary ejection is performed only on the heavy abnormal nozzle group, and is not performed on the medium abnormal nozzle group and the light abnormal nozzle group. In the high-frequency preliminary ejection, the drive signal of the high frequency acquired in step S103 is used as a preliminary ejection frequency suitable for preliminary ejection of the severely abnormal nozzle group. The ejection control unit C supplies a high-frequency drive signal to the piezoelectric element P via the driver D, and causes the severely abnormal nozzle group to eject ink. In the severe abnormal nozzle group in which the high-frequency preliminary ejection is performed, the degree of ejection abnormality is reduced to the same degree as that of the moderate abnormal nozzle group, and the first peak position of the residual signal waveform is shifted to the region II. Therefore, for the severely abnormal nozzle group, after the high-frequency preliminary ejection at step S105, the flow proceeds to step S106 to perform intermediate-frequency preliminary ejection.

In step S106, the ejection controller C performs intermediate frequency preliminary ejection. The intermediate frequency preliminary ejection is performed only on the heavy abnormal nozzle group (after the high frequency preliminary ejection is performed) and the medium abnormal nozzle group, and is not performed on the light abnormal nozzle group. In the intermediate frequency preliminary ejection, the drive signal of the intermediate frequency acquired in step S103 is used as a preliminary ejection frequency suitable for preliminary ejection of the moderately abnormal nozzle group. The ejection control unit C supplies a medium-frequency drive signal to the piezoelectric element P via the driver D to eject ink to the severe abnormal nozzle group (after completion of the high-frequency preliminary ejection) and the medium-frequency abnormal nozzle group. Here, in the severe abnormal nozzle group (after the completion of the high-frequency preliminary ejection) and the moderate abnormal nozzle group, which have undergone the intermediate-frequency preliminary ejection, the degree of ejection abnormality is reduced to the same degree as that of the mild abnormal nozzle group, and the first peak position of the residual signal waveform is shifted to the region III. Therefore, after the medium-frequency preliminary ejection in step S106, the process proceeds to step S107 to perform the low-frequency preliminary ejection for the severe-abnormality nozzle group (after the completion of the high-frequency preliminary ejection) and the medium-abnormality nozzle group.

In step S107, the ejection control unit C performs low-frequency preliminary ejection. The low-frequency preliminary ejection is performed on a heavy abnormal nozzle group (the completion of the high-frequency preliminary ejection and the intermediate-frequency preliminary ejection), a medium abnormal nozzle group (the completion of the intermediate-frequency preliminary ejection), and a light abnormal nozzle group. In the low-frequency preliminary ejection, the driving signal of the low frequency acquired in step S103 is used as a preliminary ejection frequency suitable for preliminary ejection of the slightly abnormal nozzle group. The ejection control unit C supplies a low-frequency drive signal to the piezoelectric element P via the driver D to eject ink from the heavy abnormal nozzle group (after completion of the high-frequency preliminary ejection and the intermediate-frequency preliminary ejection), the medium abnormal nozzle group (after completion of the intermediate-frequency preliminary ejection), and the light abnormal nozzle group. Here, in the heavy abnormal nozzle group (the completion of the high-frequency preliminary ejection and the intermediate-frequency preliminary ejection), the medium abnormal nozzle group (the completion of the intermediate-frequency preliminary ejection), and the light abnormal nozzle group, which have undergone the low-frequency preliminary ejection, ejection abnormality recovery may be performed, and the residual signal waveform may be the same as the reference waveform.

In step S108, the ejection control unit C acquires a residual signal waveform for each of the plurality of nozzles 19. Next, in step S109, the ejection control unit C determines whether or not each of the plurality of nozzles 19 is an abnormal ejection nozzle. Steps S108 to S109 are the same steps as steps S101 to S102, and therefore detailed description thereof is omitted. If the nozzle 19 determined to be the ejection abnormal nozzle in step S110 is not provided, the process ends. On the other hand, when the nozzle 19 having the abnormal nozzle is determined to be ejected in step S109, the routine proceeds to step S110. In step S110, the ejection control unit C sets the nozzle 19 determined to be the ejection abnormal nozzle in step S109 as an "unusable nozzle" that should not be used when ejecting ink onto the substrate 2.

Example 2 of recovery processing

Next, example 2 of the recovery process in the present embodiment will be described. Fig. 8A to 8B are flowcharts showing the restoration process of example 2 according to the present embodiment. The respective steps of the flowcharts of fig. 8A to 8B may be executed by the ejection control unit C, but may be executed by the main control unit 11. In addition, in addition to what is mentioned in embodiment 2, reference is made to embodiment 1.

In step S201, the ejection controller C acquires a residual signal waveform for each of the plurality of nozzles 19. Next, in step S202, the ejection control unit C determines whether or not each of the plurality of nozzles 19 is an abnormal ejection nozzle based on the residual signal waveform acquired in step S201. Since steps S201 to S202 are the same steps as steps S101 to S102 in fig. 7, a detailed description thereof is omitted here.

In step S203, the ejection controller C determines (specifies) a severe abnormal nozzle group from among the nozzles 19 determined to be ejection abnormal nozzles in step S202. Specifically, as described above, the ejection control section C determines, as the heavy abnormal nozzle group, the abnormal nozzles whose initial peak positions are located in the region I, based on the residual signal waveform obtained in step S201. The process proceeds to step S204 for the severely abnormal nozzle group, and proceeds to step S207 for the other nozzle groups (the moderately abnormal nozzle group ).

In step S204, the ejection control unit C obtains a preliminary ejection frequency (high frequency) suitable for preliminary ejection of the severely abnormal nozzle group. Next, in step S205, the ejection controller C performs high-frequency preliminary ejection for the weight-abnormal nozzle group. The high-frequency preliminary ejection is performed only for the severely abnormal nozzle group determined in step S203, and is not performed for the other nozzle groups (medium abnormal nozzle group, light abnormal nozzle group). Since step S204 is the same step as step S105 in fig. 7, a detailed description thereof is omitted here.

In step S206, the ejection control unit C acquires a residual signal waveform for each nozzle 19 of the severe abnormal nozzle group subjected to the high-frequency preliminary ejection, and determines whether or not the severe ejection abnormality is reduced (recovered or eliminated) based on the residual signal waveform. That is, it is determined whether or not the first peak position of the residual signal waveform is shifted from the region I by the high-frequency preliminary ejection. If the heavy ejection abnormality in the heavy abnormal nozzle group has not decreased, the routine returns to step S204. That is, the ejection control unit C repeatedly executes the high-frequency preliminary ejection until the degree of ejection abnormality of the severely abnormal nozzle group is reduced and is accommodated in a range of not more than the degree of ejection abnormality of the moderately abnormal nozzle group. For example, the ejection control unit C repeatedly executes the high-frequency preliminary ejection until the first peak position of the residual signal waveform of the severely abnormal nozzle group moves to the region II or the region III. On the other hand, when the heavy ejection abnormality in the heavy abnormal nozzle group is reduced, the flow proceeds to step S207.

In step S207, the ejection control unit C determines (specifies) a moderate abnormal nozzle group from among the nozzles 19 determined to be the ejection abnormal nozzles in step S202. More specifically, as described above, the ejection control section C determines, as a medium-level abnormal nozzle group, an abnormal nozzle whose initial peak position of the residual signal waveform is located in the region II, based on the residual signal waveform obtained in step S201. In step S207, the ejection control unit C also determines, as the moderate abnormal nozzle group, the nozzle group whose initial peak position is shifted to the region II among the severe abnormal nozzle groups in which the severe ejection abnormality is reduced by performing the high-frequency preliminary ejection (steps S204 to S206). Hereinafter, a case will be described in which the "moderate abnormal nozzle group" includes a moderate abnormal nozzle group determined based on the residual signal waveform, and a severe abnormal nozzle group in which the high-frequency preliminary ejection is performed so that the severe ejection abnormality is reduced and the peak position is moved to the region II. If it is determined that the nozzle group is a moderate abnormal nozzle group, the flow proceeds to step S208, and if it is determined that the nozzle group is other than the moderate abnormal nozzle group (mild abnormal nozzle group), the flow proceeds to step S211.

In step S208, the ejection control unit C obtains a preliminary ejection frequency (intermediate frequency) suitable for preliminary ejection of the moderate abnormal nozzle group. Next, in step S209, the ejection controller C performs intermediate frequency preliminary ejection of the medium-frequency abnormal nozzle group. The intermediate frequency preliminary ejection is performed only for the moderate abnormal nozzle group determined in step S207, and is not performed for the other nozzle groups (mild abnormal nozzle groups). Since step S209 is the same step as step S106 in fig. 7, a detailed description thereof is omitted here.

In step S210, the ejection controller C acquires a residual signal waveform for each nozzle 19 of the medium-level abnormal nozzle group on which the medium-frequency preliminary ejection is performed, and determines whether or not the medium-level ejection abnormality is reduced (recovered, eliminated) based on the residual signal waveform. That is, it is determined whether or not the first peak position of the residual signal waveform is shifted from the region II by intermediate frequency preliminary ejection. If the medium ejection abnormality in the medium abnormality nozzle group has not decreased, the flow returns to step S208. That is, the ejection control unit C repeatedly executes intermediate-frequency preliminary ejection until the degree of ejection abnormality of the moderate abnormal nozzle group is reduced and stored in the range of the degree of ejection abnormality of the mild abnormal nozzle group. For example, the ejection controller C repeatedly executes intermediate-frequency preliminary ejection until the initial peak position of the residual signal waveform of the moderately abnormal nozzle group moves to the region III. On the other hand, when the medium ejection abnormality in the medium abnormality nozzle group is reduced, the flow advances to step S211.

In step S211, the ejection control unit C determines (specifies) a slight abnormal nozzle group from the nozzles 19 determined to be ejection abnormal nozzles in step S202. Specifically, as described above, the ejection controller C determines that the abnormal nozzles whose initial peak positions are located in the region III of the residual signal waveform are the mild abnormal nozzle groups based on the residual signal waveform obtained in step S201. In step S211, the ejection control unit C determines the heavy abnormal nozzle group and the medium abnormal nozzle group, in which medium ejection abnormality is reduced by performing medium frequency preliminary ejection (steps S208 to S210), as the light abnormal nozzle group. Hereinafter, a case will be described in which the "slight-abnormality nozzle group" includes a slight-abnormality nozzle group determined based on the residual signal waveform, and a severe-abnormality nozzle group and a moderate-abnormality nozzle group in which moderate ejection abnormality is reduced by performing intermediate-frequency preliminary ejection. If it is determined that the nozzle group is a slight abnormal nozzle group, the flow proceeds to step S212, and if it is determined that the nozzle group is other than the above nozzle group, the flow ends.

In step S212, the ejection control unit C obtains a preliminary ejection frequency (low frequency) suitable for preliminary ejection of the slightly abnormal nozzle group. Next, in step S213, the ejection control unit C performs low-frequency preliminary ejection on the slightly abnormal nozzle group. The low-frequency preliminary ejection is performed only for the slightly abnormal nozzle group determined in step S2211, and is not performed for the other nozzle groups. Since step S213 is the same step as step S107 in fig. 7, a detailed description thereof is omitted here.

In step S214, the ejection control unit C acquires a residual signal waveform for each nozzle 19 of the mild abnormal nozzle group subjected to the low-frequency preliminary ejection, and determines whether or not the mild ejection abnormality is reduced (recovered or eliminated) based on the residual signal waveform. That is, it is determined whether or not the period of the waveform of the residual signal by the low-frequency preliminary ejection is the same as the reference waveform. If the slight ejection abnormality is not reduced in the slight abnormality nozzle group, the routine returns to step S212. That is, the ejection control unit C repeatedly executes the low-frequency preliminary ejection until the ejection abnormality in the slight-abnormality nozzle group is recovered (for example, until the waveform of the residual signal waveform is the same as the reference waveform). On the other hand, when the slight ejection abnormality is reduced in the slight abnormality nozzle group, the process ends.

As described above, in the present embodiment (examples 1 to 2), the following steps are performed in the recovery process for reducing (recovering and eliminating) the ejection anomalies of the plurality of nozzles 19.

(1) Only the high-frequency preliminary ejection is performed for the heavy abnormal nozzle group.

(2) After the high-frequency preliminary ejection, only the heavy abnormal nozzle group (after the high-frequency preliminary ejection is performed) and the medium abnormal nozzle group, or only the medium abnormal nozzle group is subjected to medium-frequency preliminary ejection.

(3) After the intermediate frequency preliminary ejection, the heavy abnormal nozzle group (the high frequency preliminary ejection and the intermediate frequency preliminary ejection are performed), the medium abnormal nozzle group (the intermediate frequency preliminary ejection is performed), and the light abnormal nozzle group, or the light abnormal nozzle group is subjected to the low frequency preliminary ejection.

By such recovery processing, high-frequency preliminary ejection for the medium-and mild-abnormal nozzle groups and intermediate-frequency preliminary ejection for the mild-abnormal nozzle groups are omitted, and therefore, the time and ink usage amount required for the recovery processing can be reduced.

Here, in the present embodiment, the example of classifying the degree of ejection abnormality into 3 groups (heavy, medium, light) has been described, but the degree of ejection abnormality is not limited to this, and may be classified into 2 groups or 4 or more groups. The recovery processing according to the present embodiment is processing for reducing (recovering and eliminating) ejection abnormalities caused by thickening of ink and/or sedimentation of ink components, and does not reduce ejection abnormalities caused by mixing of bubbles into the nozzles (bubble inhalation). As shown in fig. 9, the residual signal waveform is an irregular waveform with respect to the nozzle in which the ejection abnormality due to the mixing of the bubbles occurs. Accordingly, the ejection control section C can identify (determine) whether the ejection abnormality is caused by thickening of ink and/or sedimentation of ink components or by mixing of bubbles based on the residual signal waveform. By performing cleaning processing or the like using the recovery unit 8, ejection abnormalities caused by the mixing of bubbles can be reduced (recovered, eliminated).

[ sequence of operation of inkjet device ]

Next, an operation sequence of the inkjet device 1 will be described with reference to fig. 10. In step S301, the main control unit 11 controls a substrate transport device, not shown, to transport the substrate 2 into the inkjet device 1. In step S302, the ejection control unit C determines recovery of the plurality of nozzles 19 of the ejection head 5. The restoration determination is performed by determining whether or not the period (for example, the initial peak position) of the residual signal waveform is identical to the reference waveform. Specifically, the ejection control unit C supplies a specific pulse signal to the nozzle via the driver D to operate the nozzle, and detects an electrical signal corresponding to deformation of the nozzle due to a pressure wave generated by the operation of the nozzle as a residual signal. Then, the ejection control unit C determines the ejection failure state of the nozzle based on the comparison between the first peak position of the residual signal waveform and the peak position of the reference waveform. The recovery determination of the plurality of nozzles 19 may be performed before the ink is ejected. If the recovery determination is made that the discharge failure has occurred, the discharge control unit C performs a nozzle recovery process on the nozzle in step S303. The recovery process described in the foregoing embodiment 1 or embodiment 2 may be applied as the nozzle recovery process.

In step S304, the main control section 11 controls the substrate stage 3 and the alignment viewer 9 to perform alignment measurement of the substrate 2. In step S305, the main control section 11 controls the substrate stage 3 and the height sensor 10 to measure the height of the substrate 2. In addition, the order of the alignment measurement in step S304 and the height measurement in step S305 may also be reversed. Information on the position, the deformation amount, and the height of the substrate 2 obtained by the alignment measurement and the height measurement is stored in a memory within the main control section 11, for example. The main control unit 11 obtains ejection control information from pixel data including information such as pixel arrangement and pixel size formed on the substrate 2. The ejection control information includes information indicating target application distribution of ink in the pixel region 201 and the evaluation region 202 on the substrate 2.

In step S306, the ejection control unit C determines recovery of the plurality of nozzles 19 of the ejection head 5. As described above, the restoration determination is performed by determining whether the waveform (for example, the initial peak position) of the residual signal waveform is identical to the reference waveform. If the recovery determination is made that the nozzle is defective in ejection, the ejection control unit C performs the nozzle recovery process on the nozzle in step S307. Steps S306 to S307 are the same steps as those of steps S302 to S303 described above.

In step S308, the main control unit 11 synchronously drives the ejection head 5 and the substrate stage 3, and performs ejection control of ink droplets by the ejection head 5 according to the target application distribution via the ejection control unit C. In order to form a plurality of functional elements on a substrate using the inkjet device 1, a coating region to which ink is applied and the ejection head 5 are scanned relatively, and a material of the functional elements is applied. Fig. 11 shows a schematic diagram illustrating the application of material of such a functional element. In fig. 11, a substrate surface 101 is a surface of the substrate 2 on which the functional elements 102 are formed. Arrow lines 103, 104, 105, 106 indicate the scanning direction. Since fig. 11 is a schematic diagram, only 7×5 functional elements 102 are shown, but in practice a very large number of functional elements can be formed.

In step S309, the main control unit 11 determines whether or not ejection of the coating distribution to the target is completed based on the ejection control information. If the ejection is not completed, the process returns to step S306, and if the ejection is completed, the process proceeds to step S310. In step S310, the main control unit 11 controls a substrate transport device, not shown, to transport the substrate 2 out of the inkjet device 1.

[ embodiment of article manufacturing method ]

The method for manufacturing an article according to the embodiment of the present invention is suitable for manufacturing an article such as a display panel such as an organic EL, a micro device such as a semiconductor device, or an element having a fine structure. The method for manufacturing an article according to the present embodiment includes: forming a liquid film by ejecting a liquid onto a substrate using the inkjet device; drying the substrate on which the liquid film is formed, and processing the substrate on which the dried film is formed; and a step of manufacturing an article from the processed substrate. The method for producing the article includes other well-known steps (firing, cooling, cleaning, oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, and the like). The method for manufacturing an article according to the present embodiment is advantageous in at least one of performance, quality, productivity, and production cost of an article, as compared with the conventional method.

The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, to disclose the scope of the present invention, the following claims are appended.

Description of the reference numerals

1: inkjet device (substrate processing device), 2: substrate, 3: substrate stage, 5: ejection head (liquid ejection device), 9: alignment viewer, 10: height sensor, 11: main control unit, 19: nozzle (ejection element), C: ejection control unit (control unit), D: a driver.

Claims

1. A liquid ejecting apparatus is characterized in that,

the liquid ejecting apparatus includes:

a plurality of ejection elements ejecting liquid according to the drive signal; and

a control unit configured to control supply of the drive signal to each of the plurality of ejection elements,

the control unit determines, as the ejection element having the ejection abnormality, a first ejection element and a second ejection element having a degree of ejection abnormality lower than that of the first ejection element from among the plurality of ejection elements, in a recovery process of reducing the ejection abnormality of the plurality of ejection elements,

a first driving signal of a first frequency is supplied to the first ejection element without being supplied to the second ejection element,

A second driving signal of a second frequency lower than the first frequency is supplied to the second ejection element.

2. The liquid ejection device of claim 1, wherein,

in the recovery process, the control unit supplies the second drive signal to the second ejection element after supplying the first drive signal to the first ejection element.

3. The liquid ejection device of claim 1, wherein,

in the recovery process, the control unit supplies the second drive signal to the first ejection element.

4. The liquid ejection device according to any one of claims 1 to 3, wherein,

the first ejection element is an ejection element whose index indicating the degree of ejection abnormality is located in a first range, and the second ejection element is an ejection element whose index is located in a second range lower than the first range.

5. The liquid ejection device of claim 4, wherein,

the lower limit value of the index in the first range is higher than the upper limit value of the index in the second range.

6. The liquid ejection device of claim 4, wherein,

The degree of ejection abnormality of the first ejection element is reduced by supplying the first drive signal to the first ejection element such that the index moves to be within the second range.

7. The liquid ejection device of claim 6, wherein,

the control unit moves the index of the first ejection element to the second range by supplying the first drive signal to the first ejection element, and then supplies the second drive signal to the first ejection element and the second ejection element.

8. The liquid ejection device of claim 7, wherein,

the control unit repeatedly supplies the first drive signal to the first ejection element until the index of the first ejection element moves to the second range.

9. The liquid ejection device according to any one of claims 1 to 3, wherein,

the first frequency of the first driving signal is set in advance so as to reduce the degree of abnormal ejection of the first ejection element,

the second frequency of the second driving signal is set in advance so that the degree of discharge abnormality of the second discharge element is reduced.

10. The liquid ejection device according to any one of claims 1 to 3, wherein,

the liquid ejecting apparatus further includes a measuring unit that measures, for each of the plurality of ejection elements, an index indicating a degree of ejection abnormality,

the control section determines, as the first ejection element, an ejection element whose index is within a first range from among the plurality of ejection elements based on a measurement result of the measurement section, and determines, as the second ejection element, an ejection element whose index is within a second range smaller than the first range.

11. The liquid ejection device of claim 10, wherein,

the plurality of ejection elements each include a piezoelectric element,

the measuring unit detects a residual signal remaining in the piezoelectric element when a specific pressure wave is generated in the piezoelectric element, and measures the index based on a waveform of the residual signal.

12. The liquid ejection device of claim 11, wherein,

the measuring section measures the index based on a period of a waveform of the residual signal.

13. The liquid ejection device of claim 11, wherein,

The measuring unit measures the index based on an initial peak position in the waveform of the residual signal.

14. A substrate processing apparatus for processing a substrate, characterized in that,

the substrate processing apparatus includes:

a stage holding and moving the substrate; and

the liquid ejection device according to any one of claims 1 to 3, wherein a liquid is ejected onto the substrate held by the stage.

15. A method for manufacturing an article, characterized in that,

the method for manufacturing the article comprises the following steps:

a step of ejecting a liquid onto a substrate using the substrate processing apparatus according to claim 14;

a step of processing the substrate from which the liquid is discharged; and

and manufacturing an article from the processed substrate.

16. A control method of a liquid ejecting apparatus having a plurality of ejecting elements ejecting liquid according to a drive signal,

it is characterized in that the method comprises the steps of,

the control method comprises the following steps:

a determining step of determining a discharge element having a discharge abnormality from among the plurality of discharge elements; and

a recovery processing step of reducing discharge abnormality of the plurality of discharge elements,

in the determining step, when a first ejection element and a second ejection element having a degree of ejection abnormality lower than that of the first ejection element are determined as ejection elements having ejection abnormality, a first step in which a first driving signal of a first frequency is supplied to the first ejection element without being supplied to the second ejection element and a second step in which a second driving signal of a second frequency lower than the first frequency is supplied to at least the second ejection element are performed in the recovery processing step.