Liquid ejection devices, printing methods, storage media, and computer program products

Abstract

This invention provides a liquid ejection device, a printing method, a storage medium, and a computer program product. The liquid ejection device of one embodiment includes a liquid ejection head and a control unit. The liquid ejection head includes a nozzle communicating with a pressure chamber and ejecting liquid droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element that changes the pressure within the pressure chamber via a vibrating plate forming part of the wall of the pressure chamber. The control unit controls the liquid ejection head. The control unit applies a drive waveform (50) to the piezoelectric element such that liquid droplets are ejected from the nozzle more than twice in one cycle.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejection device, a printing method, and a storage medium. Background Technology

[0002] In the production of electronic devices and other manufactured objects with fine structures, inkjet liquid ejection devices are used for production (for example, see Patent Document 1). In such liquid ejection devices, control is performed so that the total ejection amount ejected from a unit region provided on the object substrate by repeatedly scanning a head equipped with a nozzle relative to the object substrate in the scanning direction becomes the ejection amount that achieves the target film thickness.

[0003] However, in the prior art, the increase in production cycle time for manufacturing objects sometimes becomes a problem. Summary of the Invention

[0004] The present invention was made in view of the above circumstances, and its object is to provide a liquid ejection device, printing method and storage medium that can shorten the production cycle time.

[0005] Solution for solving the problem

[0006] The liquid ejection device of this embodiment includes a liquid ejection head and a control unit. The liquid ejection head includes a nozzle communicating with a pressure chamber and ejecting liquid droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a vibrating plate forming part of the wall of the pressure chamber. The control unit controls the liquid ejection head. The control unit applies a drive waveform to the piezoelectric element such that it causes liquid droplets to be ejected from the nozzle more than twice in one cycle.

[0007] The liquid ejection device described above can shorten the production cycle time. Attached Figure Description

[0008] Figure 1 This is an explanatory diagram of the implementation method.

[0009] Figure 2 This is a schematic diagram of an example of a liquid ejector head.

[0010] Figure 3 This is a schematic diagram of an example of ejecting an object substrate.

[0011] Figure 4 This is an explanatory diagram of an example of the driving waveform of the implementation method.

[0012] Figure 5 This is a flowchart illustrating an example of the information processing flow performed by the control unit of the liquid ejection device according to an embodiment.

[0013] Figure 6 This is a schematic diagram of an example of a conventional driving waveform.

[0014] Figure 7A This is an illustration of a liquid film formed by applying a previously driven waveform.

[0015] Figure 7B This is an illustration of a liquid film formed by applying a previously driven waveform.

[0016] Figure 7C This is an illustration of a liquid film formed by applying a previously driven waveform.

[0017] Figure 7D This is an illustration of a liquid film formed by applying a previously driven waveform.

[0018] Figure 8A This is an illustration of a liquid film formed by applying a driving waveform according to the embodiment.

[0019] Figure 8B This is an illustration of a liquid film formed by applying a driving waveform according to the embodiment.

[0020] Figure 9A This is a graph showing the evaluation results of the ejection velocity.

[0021] Figure 9B This is a graph showing the evaluation results of the ejection velocity.

[0022] Figure 9C This is a graph showing the evaluation results of the ejection velocity.

[0023] Figure 9D This is a graph showing the evaluation results of the ejection velocity.

[0024] Figure 10A This is a graph representing the evaluation results of the permissible range of the difference in ejection volume.

[0025] Figure 10B This is a graph representing the evaluation results of the permissible range of jet velocity differences.

[0026] Figure 10C This is a graph representing the evaluation results of the landing time difference.

[0027] Figure 11 This is a graph showing the evaluation results of conventional ejection using a conventional drive waveform and embodiment ejection using an embodiment drive waveform.

[0028] Figure 12 This is a graph showing the evaluation results of conventional ejection using a conventional drive waveform and embodiment ejection using an embodiment drive waveform.

[0029] Figure 13 This is a graph showing the evaluation results of the landing of droplets ejected from the nozzle by applying a driving waveform.

[0030] Figure 14 It is a hardware structure diagram.

[0031] Explanation of reference numerals in the attached figures

[0032] 10: Liquid ejection device; 21: Control unit; 23: Nozzle; 26: Pressure chamber; 27: Vibrating plate; 28: Piezoelectric element; 24: Droplet; 25: Falling droplet; 40: Ejection target substrate; 50: Drive waveform; S: Unit area. Detailed Implementation

[0033] The embodiments of the liquid ejection device, printing method, and storage medium will now be described in detail with reference to the accompanying drawings.

[0034] Figure 1 This is an explanatory diagram of an example of System 1 in this embodiment.

[0035] System 1 includes a liquid ejection device 10 and a stage 42. The drive unit of the liquid ejection device 10 and the stage 42 are connected in a communicable manner.

[0036] The liquid ejection device 10 is an inkjet liquid ejection device that ejects droplets 24 from the nozzle 23 to the ejection target substrate 40.

[0037] The liquid ejection device 10 includes a control unit 21 and a liquid ejection head 22. The control unit 21 and the liquid ejection head 22 are connected in a communicable manner.

[0038] The liquid ejector head 22 has one or more nozzles 23 that eject liquid droplets 24. Figure 1 For simplicity, a nozzle 23 is shown. The liquid ejection head 22 is an inkjet head that ejects droplets 24 from the nozzle 23.

[0039] Figure 2 This is a schematic diagram of an example of a liquid ejector head 22.

[0040] The liquid ejector head 22 includes a nozzle 23, a pressure chamber 26, a vibrating plate 27, and a piezoelectric element 28. The nozzle 23 communicates with the pressure chamber 26 and ejects droplets 24. Liquid 29 is supplied to the pressure chamber 26 from a common flow path (not shown). The vibrating plate 27 forms part of the wall of the pressure chamber 26. The piezoelectric element 28 undergoes volume change controlled by voltage application by the control unit 21 (described later). The pressure generated by the volume change of the piezoelectric element 28 is applied to the pressure chamber 26 via the vibrating plate 27, thereby causing the pressure chamber 26 to expand and contract according to the volume change, thus ejecting droplets 24 of liquid 29 from the nozzle 23. The nozzle 23 and the piezoelectric element 28 that facilitates the ejection of droplets 24 from the nozzle 23 are arranged in a one-to-one relationship. Therefore, by controlling the voltage application of the piezoelectric element 28, the ejection of droplets 24 from the nozzle 23 corresponding to that piezoelectric element 28 is controlled. Hereinafter, the nozzle 23 and the piezoelectric element 28 that helps to eject droplets 24 from the nozzle 23 will sometimes be referred to as the piezoelectric element 28 corresponding to the nozzle 23, the nozzle 23 corresponding to the piezoelectric element 28, etc.

[0041] return Figure 1 Let's continue with the explanation.

[0042] The ejection target substrate 40 is the ejection target of the liquid ejection device 10 ejecting the liquid droplets 24.

[0043] The object to be manufactured is produced by ejecting droplets 24 onto the ejection substrate 40. Examples of objects to be manufactured include printed materials, electronic devices such as display panels, color filters, micro LEDs (Light Emitting Diodes), battery separators, perovskite solar cells, semiconductor substrates, etc. The ejection substrate 40 and the liquid 29 are pre-adjusted according to the object to be manufactured.

[0044] The target substrate 40 is placed on the stage 42. The stage 42 is configured to be scanned relative to the liquid ejection head 22 in the scanning direction X under the control of the control unit 21. For example, the control unit 21 controls the drive unit of the stage 42 to scan the stage 42 relative to the liquid ejection head 22 in the scanning direction X. Furthermore, the target substrate 40 and the stage 42 are configured to scan relative to each other in the scanning direction X. Therefore, the control unit 21 can also scan the liquid ejection head 22 relative to the target substrate 40 on the stage 42 in the scanning direction X by scanning the liquid ejection head 22 in the scanning direction X.

[0045] In this embodiment, an example will be described whereby the stage 42 is scanned relative to the liquid ejector head 22 in the scanning direction X by the control unit 21 (described later), thereby causing the ejection target substrate 40 placed on the stage 42 to be scanned relative to the liquid ejector head 22 in the scanning direction X. In this embodiment, droplets 24 are ejected from the ejection target substrate 40 during scanning at a constant speed in the scanning direction X.

[0046] Figure 3 This is a schematic diagram of an example of ejecting the target substrate 40.

[0047] Multiple unit regions S are provided on the ejection target substrate 40.

[0048] The cell region S is the ejection target region of the droplets 24 in the ejection target substrate 40. By ejecting droplets 24 into the cell region S, a liquid film based on the droplets 24 is formed in the cell region S. The ejection target substrate 40, on which the liquid film based on the droplets 24 is formed on the cell region S, undergoes various further processes to function as a manufacturing target for display panels and the like.

[0049] The size, shape, and configuration of the unit region S can be pre-adjusted according to the object being manufactured, and are not limited to... Figure 3 The method shown is applicable when the manufactured object is a display panel or other object with a fine structure, for example, the long side or diameter of the unit region S is 20 μm to 40 μm. For the unit region S, it is preferable to pre-define an effective landing area EA. The effective landing area EA is the area within the unit region S where droplets 24 are allowed to land. By spraying droplets 24 into the effective landing area EA, it is possible to prevent droplets 24 from scattering to the outside of the unit region S or to other unit regions S. The range of the effective landing area EA in the unit region S can be calculated and set in advance using known methods.

[0050] return Figure 1 Let's continue with the explanation.

[0051] The control unit 21 controls the scanning of the liquid ejector head 22 and the stage 42 in the scanning direction X, etc.

[0052] The control unit 21 is implemented by one or more processors. For example, the control unit 21 can also be implemented by having a processor such as a CPU (Central Processing Unit) execute a program, that is, by software.

[0053] The control unit 21 can also be implemented using a dedicated processor, i.e., hardware, such as an integrated circuit (IC). The control unit 21 can also be implemented using a combination of software and hardware. When using multiple processors, each processor can implement one or more of the functional units. Alternatively, it can be configured such that at least one of the functional units included in the control unit 21 is mounted on an external information processing device that is communicatively connected to the liquid dispensing device 10 via a network or the like.

[0054] The control unit 21 applies a driving waveform to the piezoelectric element 28 based on printed data. By applying a voltage represented by the driving waveform, the piezoelectric element 28 undergoes volume change according to the driving waveform, and the pressure generated by the volume change of the piezoelectric element 28 is applied to the pressure chamber 26 via the vibrating plate 27. By applying a pressure corresponding to the driving waveform to the pressure chamber 26, the pressure chamber 26 expands and contracts, thereby ejecting droplets 24 of liquid 29 from the nozzle 23 connected to the pressure chamber 26.

[0055] The printing data specifies, for each of the plurality of nozzles 23 provided in the liquid ejection head 22, data such as whether or not ejection occurs, the amount ejected, and the ejection position. The data format of the printing data can be any known format that can be used in the inkjet liquid ejection device 10.

[0056] The control unit 21 generates a drive waveform based on the printing data and applies it to the piezoelectric element 28 corresponding to each of the multiple nozzles 23 provided in the liquid ejection head 22. Furthermore, the control unit 21 applies the drive waveform to the piezoelectric element 28 to eject droplets 24 from the nozzles 23 to each unit region S of the ejection target substrate 40, which is scanned at a constant speed in the scanning direction X by the stage 42.

[0057] The driving waveform is a waveform that represents the shift of the voltage (potential) applied to the piezoelectric element 28 during one cycle. In other words, the driving waveform is a waveform that represents the shift of the voltage (potential) used to eject droplets 24 from the nozzle 23 within one cycle.

[0058] A cycle, as a unit of the driving waveform, is a unit of repeating wave elements. In this embodiment, one cycle is described as the period during which droplets 24 are ejected from a unit region S of the ejection target substrate 40 via a nozzle 23 in the scanning direction X. In other words, in this embodiment, one cycle is the period during which droplets 24 are ejected from a unit region S of the ejection target substrate 40 via a nozzle 23 provided on the liquid ejection head 22 when the liquid ejection head 22 is scanned relative to the ejection target substrate 40 in the scanning direction X. In other words, in this embodiment, one cycle is described as the period during which a nozzle 23 passes through the effective landing area EA of a unit region S of the ejection target substrate 40 along the scanning direction X.

[0059] The driving waveform in this embodiment is such that the droplet 24 is ejected from the nozzle 23 more than twice within one cycle.

[0060] Therefore, in this embodiment, by applying a driving waveform, two or more droplets 24 are ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the driving waveform is applied. Specifically, for example, in this embodiment, during one scan in the scanning direction X, two or more droplets 24 are ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the driving waveform is applied for a unit region S.

[0061] The control unit 21 calculates the number of droplets 24 ejected in one cycle based on printing data, the characteristics of the liquid 29 to be ejected, the size of the unit region S, the target film thickness, etc. Furthermore, the control unit 21 generates a drive waveform that causes the calculated number of droplets 24 to be ejected from the nozzle 23 in one cycle and applies it to the piezoelectric element 28.

[0062] Figure 4 This is an explanatory diagram of an example of the driving waveform 50 in this embodiment.

[0063] exist Figure 4 In the graph, the horizontal axis represents time, and the vertical axis represents voltage. Figure 4 The driving waveform 50 shown in the figure is used as an example to show the two droplets 24 ejected from the nozzle 23 in one cycle.

[0064] The driving waveform 50 sequentially includes a reference sustaining element P1, a pre-expansion element P2, a pre-expansion sustaining element P3, a pre-contraction element P4, a pre-sustaining element P5, an expansion element P6, an expansion sustaining element P7, a contraction element P8, a contraction sustaining element P9, an expansion element P10, an expansion sustaining element P11, a contraction element P12, a contraction sustaining element P13, an expansion element P14, and a reference sustaining element P15.

[0065] The reference sustaining element P1 is a waveform element that sustains the application of the reference voltage Vbs. The reference voltage Vbs is the applied voltage used to maintain the pressure chamber 26 at a reference volume. The pre-expansion element P2 is a waveform element that expands the volume of the pressure chamber 26 from the reference volume by decreasing the voltage from the state where the reference voltage Vbs is applied towards a second voltage V2, which is less than the reference voltage Vbs. The pre-expansion sustaining element P3 is a waveform element that sustains the application of the second voltage V2 for a specified time. The pre-contraction element P4 is a waveform element that contracts the volume of the pressure chamber 26 towards the reference volume by increasing the voltage from the state where the second voltage V2 is applied towards the reference voltage Vbs. The pre-sustaining element P5 is a waveform element that sustains the application of the reference voltage Vbs.

[0066] The expansion element P6 is a waveform element that expands the volume of the pressure chamber 26 from the reference volume by reducing the voltage from a state where a reference voltage Vbs is applied towards a first voltage V1 that is less than the second voltage V2. Through the expansion element P6, the meniscus of the liquid 29 formed in the nozzle 23 is drawn towards the pressure chamber 26, and the liquid 29 is supplied into the pressure chamber 26 from a common flow path (not shown).

[0067] The expansion sustaining element P7 is a waveform element that maintains the volume of the pressure chamber 26, which has expanded by the expansion element P6, in an expanded state for a certain period of time.

[0068] The contraction element P8 is a waveform element that causes the volume within the pressure chamber 26 to contract by increasing the voltage from a state where a first voltage V1 is applied towards a third voltage V3, which is higher than the reference voltage Vbs. Through the contraction element P8, the volume within the pressure chamber 26 contracts rapidly, pressurizing the liquid 29 within the pressure chamber 26. At the end of the contraction element P8, i.e., at time t1, the first droplet 24 is ejected from the nozzle 23. Hereinafter, the first droplet 24 ejected by applying a one-cycle drive waveform 50 will sometimes be referred to as droplet 24a. Droplet 24a is an example of droplet 24.

[0069] The contraction-maintaining element P9 is a waveform element that maintains the volume of the pressure chamber 26, which has been contracted by the contraction element P8, for a certain period of time.

[0070] The expansion element P10 is a waveform element that expands the volume of the pressure chamber 26 toward the reference volume by reducing the voltage from the state where a third voltage V3 is applied toward the reference voltage Vbs. Through the expansion element P10, the meniscus of the liquid 29 formed in the nozzle 23 is drawn toward the pressure chamber 26, and the liquid 29 is supplied into the pressure chamber 26 from a common flow path (not shown).

[0071] The expansion sustaining element P11 is a waveform element that maintains the volume of the pressure chamber 26, which has been expanded by the expansion element P10, at the reference volume for a certain period of time.

[0072] The contraction element P12 is a waveform element that causes the volume within the pressure chamber 26 to contract by increasing the voltage from the state where a reference voltage Vbs is applied towards a third voltage V3. Through the contraction element P12, the volume within the pressure chamber 26 contracts rapidly, pressurizing the liquid 29 within the pressure chamber 26. At the end of the contraction element P12, i.e., at time t2, a second droplet 24 is ejected from the nozzle 23. Hereinafter, the second droplet 24 ejected by applying a one-cycle drive waveform 50 will sometimes be referred to as droplet 24b. Droplet 24b is an example of droplet 24.

[0073] The contraction-maintaining element P13 is a waveform element that maintains the volume of the pressure chamber 26, which has been contracted by the contraction element P12, for a certain period of time.

[0074] The expansion element P14 is a waveform element that expands the volume of the pressure chamber 26 toward the reference volume by reducing the voltage from the state where a third voltage V3 is applied toward the reference voltage Vbs. Through the expansion element P14, the meniscus of the liquid 29 formed in the nozzle 23 is drawn toward the pressure chamber 26, and the liquid 29 is supplied into the pressure chamber 26 from a common flow path (not shown).

[0075] The reference sustaining element P15 is a waveform element that maintains the volume of the pressure chamber 26, which has been expanded by the expansion element P14, at the reference volume for a certain period of time.

[0076] The control unit 21 generates, for example, a process that causes two droplets 24 to be ejected within one cycle based on the printing data. Figure 4 The driving waveform 50 shown is applied to the piezoelectric element 28.

[0077] Furthermore, preferably, the control unit 21 applies a driving waveform 50 to the piezoelectric element 28 to cause multiple droplets 24 ejected from the nozzle 23 to land at different positions in the scanning direction X within one cycle. That is, preferably, the driving waveform 50 is a waveform that causes multiple droplets 24 ejected from the nozzle 23 to land at different positions in the scanning direction X within one cycle. More specifically, preferably, the driving waveform 50 is a waveform that causes multiple droplets 24 to land at different positions in the scanning direction X within the effective landing area EA of a unit region S.

[0078] Furthermore, it is preferable that the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 in a manner that adjusts the plurality of droplets 24 ejected from the nozzle 23 within one cycle to prevent them from converging during the period from ejection to landing. That is, it is preferable that the drive waveform 50 is a waveform that adjusts the plurality of droplets 24 ejected from the nozzle 23 within one cycle to prevent them from converging during the period from ejection to landing. More specifically, it is preferable that the drive waveform 50 is a waveform that adjusts the plurality of droplets 24 ejected from the nozzle 23 within one cycle to prevent them from converging during the period until they land in the effective landing region EA of a unit region S.

[0079] Furthermore, preferably, the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 such that at least one of the ejection velocity and ejection amount of the plurality of droplets 24 ejected from the nozzle 23 is the same among the plurality of droplets 24 in one cycle. That is, preferably, the drive waveform 50 is a waveform that makes at least one of the ejection velocity and ejection amount of the plurality of droplets 24 ejected from the nozzle 23 the same among the plurality of droplets 24 in one cycle.

[0080] Specifically, preferably, the difference in ejection velocity among the plurality of droplets 24 ejected from the nozzle 23 within one cycle by applying the drive waveform 50 is less than 10%, and particularly preferably zero. A zero difference in ejection velocity means that the ejection velocities among the plurality of droplets 24 are the same.

[0081] Furthermore, in detail, it is preferable that the difference in ejection amount among the plurality of droplets 24 ejected from the nozzle 23 within one cycle by applying the driving waveform 50 is less than 35%, more preferably less than 20%, and particularly preferably zero. A difference in ejection amount of zero means that the ejection amounts among the plurality of droplets 24 are the same.

[0082] Furthermore, sometimes the drive waveform 50 is adjusted so that one of the ejection velocity and ejection amount of the multiple droplets 24 ejected from the nozzle 23 in one cycle is adjusted in the same way among the multiple droplets 24, thereby making the other value different among the multiple droplets 24. In this case, the control unit 21 can adjust the drive waveform 50 so that the ejection velocity of the multiple droplets 24 is adjusted in the same way among the multiple droplets 24.

[0083] Furthermore, it is preferable that the control unit 21 adjusts the landing time difference of each droplet 24 among the plurality of droplets 24 ejected from the nozzle 23 in one cycle on the ejection target substrate 40 to satisfy the above conditions.

[0084] Alternatively, preferably, the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 after adjusting the ejection amount of each droplet 24 among the plurality of droplets 24 in such a way as to make the thickness of the liquid film formed by the landing of the plurality of droplets 24 a target thickness.

[0085] The control unit 21 adjusts the ejection amount corresponding to each droplet in such a way that the thickness of the partial liquid film formed in the unit region S of the ejection target substrate 40 by each droplet 24 of the plurality of droplets 24 ejected from the nozzle 23 in one cycle is the thickness obtained by dividing the target film thickness in the unit region S by the number of droplets ejected in one cycle.

[0086] The control unit 21 can calculate the target film thickness using known methods such as analyzing printing data. For example, the control unit 21 can determine the area of ​​each unit region S in the unit region S and the target total amount of liquid 29 to be ejected from each unit region S based on the printing data, and calculate the thickness of the liquid 29 in the unit region S when the target total amount of liquid 29 is ejected into the unit region S of that area as the target film thickness.

[0087] Furthermore, the control unit 21 adjusts the drive waveform 50 and applies it to the piezoelectric element 28 in a manner that satisfies at least one of the velocity condition of the plurality of droplets 24 ejected in one cycle and the ejection quantity condition of the plurality of droplets 24. As described above, the application of the drive waveform 50 to the piezoelectric element 28 by the control unit 21 is performed when the ejection target substrate 40 is scanned at a constant speed relative to the liquid ejection head 22 in the scanning direction X.

[0088] The velocity condition is at least one of the following: multiple droplets 24 ejected from nozzle 23 within one cycle land at different positions in the scanning direction X; these multiple droplets 24 do not merge during the period from being ejected to landing; and the ejection velocity of these multiple droplets 24 is the same.

[0089] The ejection rate condition is that the ejection rate of multiple droplets 24 ejected from the nozzle 23 in one cycle is the same, and the thickness of the liquid film formed by the landing of multiple droplets 24 ejected from the nozzle 23 in one cycle is the target film thickness.

[0090] use Figure 4 The adjustment method for the drive waveform 50 that meets the above speed and ejection quantity conditions is explained in detail. For example... Figure 4 As shown, the illustration assumes that the number of droplets 24 ejected in one cycle is two.

[0091] The position of the droplet 24 landing on the droplet 25 in the scanning direction X is adjusted by the ejection speed of the ejected droplet 24. In addition, the ejection speed of the droplet 24 is also adjusted to prevent the first droplet 24a and the second droplet 24b from being ejected until landing.

[0092] The ejection velocity of the droplets 24 is adjusted by controlling the slopes of the contraction elements P8 and P12 in the driving waveform 50, which cause each droplet 24 (first droplet 24a, second droplet 24b) to eject at ejection timings (timing t1, timing t2). A larger slope of contraction element P8 results in a faster ejection velocity of the first droplet 24. Similarly, a larger slope of contraction element P12 results in a faster ejection velocity of the second droplet 24.

[0093] Additionally, the ejection velocities of multiple droplets 24 (first droplet 24a, second droplet 24b) can be adjusted by modifying periods T5 and T6 in the driving waveform 50. Period T5 is the total time of the contraction element P8 and the contraction maintenance element P9. Period T6 is the total time of the expansion element P10 and the expansion maintenance element P11.

[0094] Specifically, the ejection velocity of the first droplet 24a is adjusted by adjusting the slope of the contraction element P8 and the period T5. The ejection velocity of the second droplet 24b is adjusted by adjusting the periods T5 and T6, as well as the slope of the contraction element P12.

[0095] The ejection volume of the droplets 24 is adjusted by the voltage difference between the starting and ending ends of the contraction elements P8 and P12 of each droplet 24 (first droplet 24a, second droplet 24b) ejected at ejection timings (timing t1, timing t2).

[0096] Furthermore, the ejection volume of the first droplet 24a is also affected by the waveform elements adjusted before the ejection of the first droplet 24a, namely, the reference maintenance element P1, the pre-expansion element P2, the pre-expansion maintenance element P3, the pre-contraction element P4, the pre-maintenance element P5, the expansion element P6, and the expansion maintenance element P7. These reference maintenance elements P1, pre-expansion element P2, pre-expansion maintenance element P3, pre-contraction element P4, pre-maintenance element P5, expansion element P6, and expansion maintenance element P7 are equivalent to the pre-resonance elements before the ejection of the first droplet 24a.

[0097] In addition, the ejection volume of the second droplet 24a is also affected by the timing of adjusting the starting end of the contraction element P12 to cause the residual vibration resonance in the pressure chamber 26 caused by the ejection of the first droplet 24a.

[0098] The control unit 21 adjusts the drive waveform 50 by combining these adjustments to satisfy at least one of the above-mentioned velocity conditions and ejection quantity conditions of the multiple droplets 24 ejected in one cycle, and then applies the drive waveform 50 to the piezoelectric element 28.

[0099] Furthermore, when the liquid ejection device 10 is equipped with multiple nozzles 23, the ejection characteristics of each nozzle 23 may differ. Therefore, the control unit 21 adjusts the drive waveform 50 for each nozzle 23 in a manner that satisfies at least one of the aforementioned velocity conditions and ejection quantity conditions of the multiple droplets 24 ejected in one cycle, and applies the drive waveform 50 to the piezoelectric element 28 corresponding to the nozzle 23, based on the ejection characteristics and structure of the nozzle 23. The control unit 21 can obtain the ejection characteristics of each nozzle 23 using known methods.

[0100] return Figure 3 Let's continue with the explanation.

[0101] The control unit 21 applies a drive waveform 50 to the piezoelectric element 28 of the liquid ejection head 22, which is being scanned relative to the ejection target substrate 40 at a constant speed in the scanning direction X. Therefore, in one scan in the scanning direction X, a liquid is ejected from a nozzle 23 to a unit region S and landing droplets 25a and 25b based on droplets 24a are formed at different positions in the scanning direction X.

[0102] Therefore, in the liquid ejection apparatus 10 of this embodiment, it is possible to reduce the number of scans of the nozzle 23 (liquid ejection head 22) relative to the ejection target substrate 40 in the scanning direction X, so that the total ejection amount of liquid 29 ejected for the unit region S provided on the ejection target substrate 40 is set to the ejection amount that achieves the target film thickness.

[0103] For example, as described above, by applying a drive waveform 50 to the piezoelectric element 28 to make the thickness of the liquid film formed by the landing of multiple droplets 24 ejected from the nozzle 23 in one cycle the target film thickness, it is possible to control the total amount of multiple droplets 24 ejected from the unit region S of the ejection target substrate 40 in a single scan in the scanning direction X to achieve the ejection amount that achieves the target film thickness.

[0104] Next, an example of the information processing flow performed by the control unit 21 of this embodiment will be described.

[0105] Figure 5 This is a flowchart illustrating an example of the information processing flow performed by the control unit 21 of the liquid ejection device 10 in this embodiment.

[0106] The control unit 21 of the liquid dispensing device 10 acquires printing data (step S100). For example, the control unit 21 acquires printing data by generating printing data using a known method. Alternatively, the control unit 21 may acquire printing data by receiving printing data from an external information processing device, storage device, or the like that connected via a network in a communicable manner.

[0107] Based on the printing data obtained in step S100, the control unit 21 generates a drive waveform 50 that is applied to the piezoelectric element 28 corresponding to each of the plurality of nozzles 23 provided in the liquid ejection device 10 (step S102).

[0108] The control unit 21 performs the following printing control: the stage 42 scans relative to the liquid ejector head 22 at a constant speed in the scanning direction X, and applies the drive waveform 50 generated in step S102 (step S104) to the corresponding piezoelectric element 28. Through the processing of step S104, two or more droplets 24 are ejected from the nozzle 23 in one cycle, and landing droplets 25 based on multiple nozzles 23 are formed at different positions in the scanning direction X within a unit region S, forming a liquid film based on multiple landing droplets 25.

[0109] Then, this routine ends.

[0110] As explained above, the liquid ejection device 10 of this embodiment includes a liquid ejection head 22 and a control unit 21. The liquid ejection head 22 includes a nozzle 23 communicating with a pressure chamber 26 and ejecting liquid droplets 24, a pressure chamber 26 communicating with the nozzle 23, and a piezoelectric element 28 that changes the pressure inside the pressure chamber 26 via a vibrating plate 27 forming part of the wall of the pressure chamber 26. The control unit 21 controls the liquid ejection head 22. The control unit 21 applies a drive waveform 50 to the piezoelectric element 28 such that the liquid droplets 24 are ejected from the nozzle 23 more than twice in one cycle.

[0111] Here, when the conventional drive waveform is applied to the piezoelectric element 28, the increase in production cycle time becomes a problem.

[0112] Figure 6 This is a schematic diagram of an example of a previous drive waveform 500.

[0113] Conventional drive waveform 500 represents the shift in voltage (potential) used to eject one droplet 24 from nozzle 23 within one cycle. Conventional drive waveform 500 does not include... Figure 4 The expansion sustaining element P11, contraction element P12, contraction sustaining element P13, and expansion element P14 in the driving waveform 50 of this embodiment shown for ejecting the second droplet 24b.

[0114] Therefore, within one cycle, a droplet 24 is ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the previous drive waveform 500 was applied.

[0115] Therefore, when applying the conventional drive waveform 500 to the piezoelectric element 28, in order to achieve the target film thickness, the nozzle 23 (liquid ejection head 22) needs to be scanned multiple times in the scanning direction X relative to the ejection target substrate 40. Therefore, in the prior art, the increase in the production cycle time of manufacturing the object sometimes becomes a problem.

[0116] On the other hand, in the liquid ejection device 10 of this embodiment, a drive waveform 50 is applied to the piezoelectric element 28 such that the droplets 24 are ejected from the nozzle 23 more than twice in one cycle. Therefore, in the liquid ejection device 10 of this embodiment, the number of scans in the scanning direction X for achieving the ejection amount of the target film thickness can be reduced.

[0117] Therefore, in the liquid ejection device 10 of this embodiment, the production cycle time can be shortened.

[0118] Furthermore, in this embodiment, the liquid ejection head 22 is scanned relative to the ejection target substrate 40 in the scanning direction X. Moreover, one cycle is the period of movement in the scanning direction X during which a droplet 24 can be ejected from a unit region S of the ejection target substrate 40 via a nozzle 23. Specifically, one cycle is the period during which the nozzle 23 passes through the effective landing area EA of a unit region S in the ejection target substrate 40 along the scanning direction X.

[0119] Therefore, in the liquid ejection apparatus 10 of this embodiment, by applying a driving waveform 50 to the liquid ejection head 22, which is scanned relative to the ejection target substrate 40 in the scanning direction X, the ejection of droplets 24 of the unit region S can be completed in a single scan in the scanning direction X. Therefore, in the liquid ejection apparatus 10 of this embodiment, the number of scans in the scanning direction X can be reduced to set the total ejection amount of liquid 29 ejected from the unit region S provided on the ejection target substrate 40 to achieve the target film thickness.

[0120] In addition, the control unit 21 of the liquid ejection device 10 of this embodiment applies a drive waveform 50 to the piezoelectric element 28, causing multiple droplets 24 ejected from the nozzle 23 to land at different positions in the scanning direction X within one cycle.

[0121] Therefore, within one cycle, multiple droplets 24 ejected from nozzle 23 land at different positions along the scanning direction X of the substrate 40 to be ejected. Thus, it is possible to improve the uniformity of the liquid film thickness formed by ejecting multiple droplets 24 within one cycle.

[0122] Furthermore, in the liquid ejection apparatus 10 of this embodiment, since the uniformity of the film thickness of the liquid film formed by ejecting the droplets 24 can be improved, when the manufactured object produced by ejecting the droplets 24 onto the ejection target substrate 40 is a display panel, the brightness unevenness of the display panel can be suppressed.

[0123] In addition, the control unit 21 of this embodiment applies a drive waveform 50 to the piezoelectric element 28 in a manner that causes the plurality of droplets 24 ejected from the nozzle 23 in one cycle to not be combined during the period from being ejected to landing.

[0124] Therefore, within one cycle, multiple droplets 24 ejected from nozzle 23 fly toward the ejection target substrate 40 as individual droplets 24 and land on the ejection target substrate 40. Thus, it is possible to improve the uniformity of the liquid film thickness formed by ejecting multiple droplets 24 in one cycle.

[0125] Furthermore, in the liquid ejection device 10 of this embodiment, a drive waveform 50 is applied to the piezoelectric element 28 such that the droplets 24 are ejected from the nozzle 23 more than twice in one cycle. Therefore, it is possible to achieve uniform thickness of the liquid film formed by the falling droplets 25 of the droplets 24.

[0126] Figures 7A to 7D This is an explanatory diagram of a liquid film 30 formed by applying a conventional drive waveform 500. Figures 7A to 7D The diagram shows a state where a conventional drive waveform 500 is applied to the piezoelectric element 28 and the liquid ejector head 22 is scanned multiple times in the scanning direction X to form a liquid film 30 of the target thickness in the cell region S. The conventional drive waveform 500 is... Figure 6 The previously shown driving waveform is 500.

[0127] like Figure 7A As shown, by applying a conventional driving waveform 500 to the piezoelectric element 28, a droplet 24 is ejected in a single scan in the scanning direction X for the cell region S, and a settling droplet 25 is formed within the cell region S. The settling droplet 25 within the cell region S wets and extends within the cell region S, forming a liquid film 30 within the cell region S. Figure 7BNext, the liquid ejector head 22 is scanned again in the scanning direction X, and a droplet 24 is ejected onto the liquid film 30 in the cell region S by applying the previous drive waveform 500 to the piezoelectric element 28, and a settling droplet 25 is formed on the liquid film 30. Figure 7C Then, on the liquid film 30 formed by the landing droplets 25 obtained during the previous and subsequent scans in the scanning direction X, a liquid film 30 formed by the landing droplets 25 obtained during the current scan in the scanning direction X is stacked (see reference). Figure 7C , Figure 7D ).

[0128] Therefore, as Figure 7D As shown, in the prior art, in each scan of multiple scans in the scanning direction X, a droplet 25 is formed in the cell region S. Therefore, due to the influence of the wettability between the liquid films 30 formed by the droplet 25 in each scan in the scanning direction X, the shape of the liquid film 30 is deformed and the film thickness becomes uneven.

[0129] Figures 8A-8B This is an explanatory diagram of the liquid film 30 formed by applying the driving waveform 50 of this embodiment. Figures 8A-8B This is an illustration of how multiple droplets 24 are ejected in one cycle to form a liquid film 30 of target thickness in a cell region S by applying a driving waveform 50 to a piezoelectric element 28 in one scan of the liquid ejector head 22 in the scanning direction X.

[0130] like Figure 8A As shown, by applying a driving waveform 50 to the piezoelectric element 28, multiple droplets 24 are ejected to different positions within the cell region S in a single scan along the scanning direction X, forming landing droplets 25. The multiple landing droplets 25, landing at different positions within the cell region S, form a liquid film 30 through wet stretching. Figure 8B ).

[0131] like Figure 8B As shown, in this embodiment, multiple falling droplets 25 are formed at different positions within the cell region S during a single scan in the scanning direction X, thereby improving the uniformity of the film thickness of the liquid film 30 formed by the multiple falling droplets 25.

[0132] In addition, the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 such that at least one of the ejection speed and ejection amount of the plurality of droplets 24 ejected from the nozzle 23 in one cycle is the same among the plurality of droplets 24.

[0133] Therefore, it is possible to efficiently adjust the position of each droplet 24 that lands on the droplet 25 and the thickness of the liquid film formed by the landing droplet 25 among the multiple droplets 24 ejected in one cycle.

[0134] In addition, the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 after adjusting the ejection amount of each droplet 24 in a manner that makes the thickness of the liquid film formed by the landing droplets 25 of the plurality of droplets 24 become the target film thickness.

[0135] Therefore, in the liquid ejection device 10 of this embodiment, it is possible to eject droplets 24 of the target film thickness in a single scan in the scanning direction X, thereby reducing the number of scans in the scanning direction X.

[0136]

Example

[0137] The liquid ejection device 10 of this embodiment will now be described in detail through examples. However, the liquid ejection device 10 of this embodiment is not limited to the following examples.

[0138] Figures 9A to 9D This is a graph showing the evaluation results of the ejection velocities of each droplet, including the first droplet 24a and the second droplet 24b. Figures 9A to 9D The middle shows the Figure 4 The periods T5, T6, and T7 in the driving waveform 50 shown represent the evaluation results of the ejection velocities of the first droplet 24a and the second droplet 24b when adjusted. Period T4 is the total time of the expansion element P6 and the expansion maintenance element P7. Period T7 is the total time of the contraction element P12 and the contraction maintenance element P13.

[0139] Figure 9A This is an explanatory diagram showing the measurement results of the ejection velocities of the first droplet 24a and the second droplet 24b when the period T5 in the driving waveform 50 was changed. Figure 9A In the diagram, the horizontal axis represents period T5, and the vertical axis represents the ejection velocity of droplet 24. Figure 9A The figure shows the measurement results of the ejection velocities of the first droplet 24a and the second droplet 24b ejected from the nozzle 23 corresponding to the piezoelectric element 28 when the driving waveform 50 of the period T5 was changed only when the conditions other than the period T5 were kept constant.

[0140] like Figure 9A As shown, by changing the period T5, the ejection velocities of each droplet of the first droplet 24a and the second droplet 24b changed. Figure 9AIn the evaluation results shown, when the period T5 is 1.5 × the period T4, the velocities of the first droplet 24a and the second droplet 24b are approximately the same.

[0141] Figure 9B This is an explanatory diagram showing the evaluation results of the ejection velocities of the first droplet 24a and the second droplet 24b when the period T6 in the driving waveform 50 was changed. Figure 9B In the diagram, the horizontal axis represents period T6, and the vertical axis represents the ejection velocity of droplet 24. Figure 9B The figure shows the measurement results of the ejection velocities of the first droplet 24a and the second droplet 24b ejected from the nozzle 23 corresponding to the piezoelectric element 28 when the driving waveform 50 of the period T6 was changed only when the conditions other than the period T6 were kept constant.

[0142] like Figure 9B As shown, by changing the period T6, the ejection velocity of the second droplet 24b was primarily altered. Figure 9B In the evaluation results shown, when the period T6 is 0.9 × the period T4, the first droplet 24a and the second droplet 24b have approximately the same speed, and the first droplet 24a has the fastest speed.

[0143] Figure 9C This is an explanatory diagram showing the evaluation results of the ejection velocities of the first droplet 24a and the second droplet 24b when the period T7 in the driving waveform 50 was changed. Figure 9C In the diagram, the horizontal axis represents period T7, and the vertical axis represents the ejection velocity of droplet 24. Figure 9C The figure shows the measurement results of the ejection velocities of the first droplet 24a and the second droplet 24b ejected from the nozzle 23 corresponding to the piezoelectric element 28 when the drive waveform 50 of the period T7 was changed while the conditions other than the period T7 were kept constant.

[0144] like Figure 9C As shown, even when the period T7 is changed, the ejection velocities of the first droplet 24a and the second droplet 24b remain unchanged. Therefore, it can be considered that adjusting the period T7 has no effect on the ejection velocities of the first droplet 24a and the second droplet 24b. Furthermore, when the period T7 is adjusted to 2.3 × period T4, the residual vibration generated in the pressure chamber 26 by ejecting each droplet of the first droplet 24a and the second droplet 24b is minimized. Therefore, it can be considered that adjusting the period T7 helps to reduce residual vibration.

[0145] Figure 9D This is an explanatory diagram showing the measurement results of the ejection volume of each droplet of the first droplet 24a and the second droplet 24b when the period T7 in the driving waveform 50 was changed. Figure 9D In the figure, the horizontal axis represents period T7, and the vertical axis represents the ejection volume of droplet 24. Figure 9D This indicates the measurement results of the ejection amount of each droplet of the first droplet 24a and the second droplet 24b ejected from the nozzle 23 corresponding to the piezoelectric element 28 when the driving waveform 50 of the period T7 is changed only when the conditions other than the period T7 are set constant.

[0146] like Figure 9D As shown, even when the period T7 is changed, the ejection amounts of the first droplet 24a and the second droplet 24b do not change. However, the ejection amount of the second droplet 24b is greater than that of the first droplet 24a. Therefore, it can be assumed that when the adjustment is made so that the relationship between the velocities of the first droplet 24a and the second droplet 24b satisfies the above-mentioned velocity condition, sometimes the volumes of the first droplet 24a and the second droplet 24b are not the same, and the ejection amount of the second droplet 24b increases.

[0147] Here, the ejection velocities of droplets 24a and 24b also affect the landing positions of each droplet on the ejection target substrate 40. Therefore, as described above, it can be assumed that the control unit 21 generates a drive waveform 50 with adjustments to the slope of the contraction element P8, the period T5, the period T6, and the slope of the contraction element P12, in a manner that prioritizes satisfying the speed condition over satisfying the ejection amount condition, and applies this drive waveform 50 to the piezoelectric element 28.

[0148] Figures 10A to 10C It is a graph showing the evaluation results of the allowable ranges of the difference in ejection velocity and the difference in ejection volume.

[0149] Figure 10A This indicates that an electric field is applied to the piezoelectric element 28 corresponding to each of the 150 nozzles 23 provided in the liquid ejector head 22. Figure 4 The evaluation results show the ejection volume of each droplet 24a and droplet 24b ejected from each nozzle 23, and the total ejection volume of each nozzle 23, under the driving waveform 50 shown. Figure 10A In the diagram, the horizontal axis represents the identification number of nozzle 23, and the vertical axis represents the ejection volume of droplets 24. The ejection volume is expressed in terms of volume.

[0150] like Figure 10AAs shown, the ejection volume of the first droplet 24a ejected from each of the plurality of nozzles 23 is in the range of 2.2pl ± 7.5%. Furthermore, the ejection volume of the second droplet 24b ejected from each of the plurality of nozzles 23 is in the range of 2.6pl ± 5.1%. Additionally, the total ejection volume of droplets 24a and 24b ejected from each of the plurality of nozzles 23 is 4.8pl ± 2.6%. Therefore, the permissible range for the difference between the ejection volumes of the first droplet 24a and the second droplet 24b is 10% to 35%.

[0151] That is, as described in the above embodiments, the difference in ejection amount between the plurality of droplets 24 ejected from the nozzle 23 within one cycle, which is included in the ejection amount condition, is preferably 35% or less, more preferably 20% or less, and particularly preferably zero.

[0152] Figure 10B This indicates that an electric field is applied to the piezoelectric element 28 corresponding to each of the 150 nozzles 23 provided in the liquid ejector head 22. Figure 4 The evaluation results of the ejection velocities of each droplet 24a and 24b ejected from each nozzle 23 under the driving waveform 50 shown. Figure 10B In the diagram, the horizontal axis represents the identification number of nozzle 23, and the vertical axis represents the ejection velocity of droplet 24.

[0153] like Figure 10B As shown, the ejection velocity of the first droplet 24a ejected from each of the plurality of nozzles 23 is in the range of 6.0 m / s ± 18%. Furthermore, the ejection velocity of the second droplet 24b ejected from each of the plurality of nozzles 23 is in the range of 4.9 m / s ± 20%.

[0154] Figure 10C This indicates that an electric field is applied to the piezoelectric element 28 corresponding to each of the 150 nozzles 23 provided in the liquid ejector head 22. Figure 4 The evaluation results of the time difference (landing time difference) between the droplets 24a and 24b ejected from each nozzle 23 during the driving waveform 50 shown. Figure 10C In the diagram, the horizontal axis represents the identification number of nozzle 23, and the vertical axis represents the landing time difference. Figure 10C The evaluation shown was conducted with the distance between the nozzle 23 and the ejection target substrate 40 set to 0.45 mm. Figure 10C Indicates will Figure 4 The results are shown for the cases where the length of one cycle of the driving waveform 50 is set to 40 μsec (frequency 25 kHz) and the length of one cycle is set to 33 μsec (frequency 30 kHz).

[0155] like Figure 10C As shown, when a driving waveform 50 with a period of 40 μsec (frequency 25 kHz) is applied, the time difference between the fall of droplets 24a and 24b is large enough that it can be assumed that droplets 24a and 24b do not merge until they fall. On the other hand, when a driving waveform 50 with a period of 33 μsec (frequency 30 kHz) is applied, the time difference between the fall of droplets 24a and 24b is zero. Therefore, according to Figure 10B and Figure 10C The results suggest that, during the application of a drive waveform 50 with a period of 33 μsec (frequency 30 kHz), as long as the difference in ejection velocity between droplets 24a and 24b is less than 10%, the confluence of droplets until landing can be suppressed.

[0156] Therefore, it can be considered that the permissible range of the difference in ejection velocity between the first droplet 24a and the second droplet 24b is 10% or less. That is, as explained in the above embodiment, the difference in ejection velocity among the plurality of droplets 24 ejected from the nozzle 23 in one cycle, which is included in the velocity condition, is preferably 10% or less among the plurality of droplets 24, and particularly preferably zero.

[0157] Figure 11 This is a graph showing the evaluation results of conventional ejection using the conventional drive waveform 500 and ejection of this embodiment using the drive waveform 50 of this embodiment.

[0158] exist Figure 11 In the example shown, as a previous ejection, it is demonstrated by applying force to the piezoelectric element 28. Figure 6 The evaluation results shown in the conventional drive waveform 500 are the landing droplets 25 formed by the droplets 24 ejected from the ejection target substrate 40, which is being scanned at a constant speed in the scanning direction X, from the nozzle 23 corresponding to the piezoelectric element 28.

[0159] In addition, Figure 11 In this embodiment, the ejection is shown by applying force to the piezoelectric element 28. Figure 4 The driving waveform 50 shown is an evaluation result of the landing droplets 25 formed by the droplets 24 ejected from the ejection target substrate 40 at a constant speed in the scanning direction X by the nozzle 23 corresponding to the piezoelectric element 28.

[0160] In addition, Figure 11 In this embodiment, the evaluation results of the landing droplets 25 formed by the droplets 24 ejected from the two nozzles 23 when a drive waveform 50 is applied to the piezoelectric element 28 corresponding to the two nozzles 23 are shown.

[0161] like Figure 11As shown, it can be confirmed that the ejection speed of each droplet, the first droplet 24a and the second droplet 24b ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the driving waveform 50 of this embodiment is applied, can achieve an ejection speed that is approximately the same as the ejection speed of a droplet 24 ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the conventional driving waveform 500 is applied.

[0162] In addition, such as Figure 11 As shown, even when the same driving waveform 50 is applied to the two piezoelectric elements 28 respectively, the landing time difference and landing position difference of the droplets 24a and 25b ejected from the nozzles 23 corresponding to the two piezoelectric elements 28 are different between the nozzles 23.

[0163] Therefore, it can be considered that, regarding the drive waveform 50, it is preferable to adjust the drive waveform 50 according to the characteristics of the nozzle 23 in a manner that satisfies at least one of the speed condition and the ejection quantity condition described above for each nozzle 23.

[0164] Figure 12 This is a graph showing the evaluation results of conventional ejection using the conventional drive waveform 500 and ejection of this embodiment using the drive waveform 50 of this embodiment.

[0165] exist Figure 12 In the example shown, as a previous ejection, it is demonstrated by applying force to the piezoelectric element 28. Figure 6 The evaluation results of the ejection speed and ejection angle of the droplets 24 ejected from the nozzle 23 corresponding to the piezoelectric element 28 to the ejection target substrate 40 which is scanning at a constant speed in the scanning direction X are shown in the conventional drive waveform 500.

[0166] In addition, Figure 12 In this embodiment, the ejection is shown by applying force to the piezoelectric element 28. Figure 4 The driving waveform 50 shown represents the evaluation results of the ejection speed and ejection angle of the droplets 24 ejected from the nozzle 23 corresponding to the piezoelectric element 28 at a constant speed on the ejection target substrate 40 in the scanning direction X.

[0167] Figure 12 The horizontal axis of the graph shown represents the identification number of nozzle 23. Figure 12 The vertical axis of the upper-level chart shown represents the ejection speed. Figure 12 The vertical axis of the lower-level chart shown represents the ejection angle.

[0168] like Figure 12As shown, it can be confirmed that the ejection speed and ejection angle of each droplet, the first droplet 24a and the second droplet 24b ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the driving waveform 50 of this embodiment is applied, can achieve approximately the same ejection speed and ejection angle as the ejection speed and ejection angle of a droplet 24 ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the conventional driving waveform 500 is applied.

[0169] Figure 13 This is a diagram showing the evaluation results of the landing droplets 25 formed by the droplets 24 ejected from the nozzle 23 by applying the driving waveform 50.

[0170] exist Figure 13 The image shows two consecutive applications of time sequence to the piezoelectric element 28. Figure 4 The evaluation results of the landing droplets 25 formed by the droplets 24 ejected from the nozzle 23 corresponding to the piezoelectric element 28 when the driving waveform 50 is shown. Figure 13 As shown, when the target substrate 40 is scanned at a constant speed in the scanning direction X and two driving waveforms 50 are continuously applied to the piezoelectric element 28, the landing droplets 25a and 25b corresponding to the droplets 24a and 24b based on the first driving waveform 50, and the landing droplets 25c and 25d corresponding to the droplets 24a and 24b based on the second driving waveform 50 are formed at different positions in the scanning direction X on the target substrate 40.

[0171] The landing time difference between landing droplets 25a and 25b in the scanning direction X is 11 μsec. Furthermore, the landing time difference between landing droplets 25a and 25d in the scanning direction X is 33 μsec. Additionally, the landing time difference between landing droplets 25c and 25d in the scanning direction X is 11 μsec.

[0172] Therefore, it can be considered that by applying the driving waveform 50 of this embodiment to the piezoelectric element 28, multiple droplets 24 can be ejected at a high frequency of 90 kHz or higher within one cycle.

[0173] Next, an example of the hardware structure of the control unit 21 of the liquid ejection device 10 in this embodiment will be described.

[0174] Figure 14 This is a hardware structure diagram of an example of the control unit 21 of the liquid ejection device 10 in this embodiment.

[0175] In this embodiment, the control unit 21 of the liquid ejection device 10 interconnects the CPU 10A, ROM (Read-Only Memory) 10B, RAM (Random Access Memory) 10C and I / F unit 10D via bus 10E, thus utilizing a typical computer hardware structure.

[0176] The CPU 10A is a computing device that controls the control unit 21 of the liquid ejection device 10 in this embodiment. The ROM 10B stores programs that implement information processing by the CPU 10A. The RAM 10C stores data required for various processes performed by the CPU 10A. The I / F unit 10D is an interface for sending and receiving data.

[0177] In the control unit 21 of the liquid dispensing device 10 of this embodiment, the CPU 10A reads the program from the ROM 10B into the RAM 10C and executes the program, thereby implementing the aforementioned functional units on the computer. The program for executing the aforementioned processes performed by the control unit 21 of the liquid dispensing device 10 of this embodiment can also be stored in an HDD (hard disk drive). In addition, the program for executing the processes described later by the control unit 21 of the liquid dispensing device 10 of this embodiment can also be pre-loaded into the ROM 10B.

[0178] Furthermore, the program for executing the information processing performed by the control unit 21 of the liquid dispensing device 10 of this embodiment can also be stored in the form of an installable or executable file on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD (Digital Versatile Disk), or floppy disk (FD) and provided as a computer program product. Alternatively, the program for executing the information processing performed by the control unit 21 of the liquid dispensing device 10 of this embodiment can be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program for executing the information processing performed by the control unit 21 of the liquid dispensing device 10 of this embodiment can be provided or distributed via a network such as the Internet.

[0179] Furthermore, while embodiments of this disclosure have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its variations are included within the scope and spirit of the invention, and are also included within the scope of the invention as described in the claims and its equivalents.

[0180] Furthermore, this technology can adopt the following structure.

[0181] <Postscript> (1)

[0183] A liquid ejection device, comprising:

[0184] A liquid ejector head comprising a nozzle communicating with a pressure chamber and ejecting liquid droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element for changing the pressure within the pressure chamber via a vibrating plate forming part of a wall of the pressure chamber; and

[0185] The control unit controls the liquid ejection head.

[0186] The control unit applies a driving waveform to the piezoelectric element such that the droplets are ejected from the nozzle more than twice within one cycle. (2)

[0188] According to the liquid ejection device described in (1) above, wherein,

[0189] The liquid ejector head is scanned relative to the ejection target substrate, which has a unit region as the ejection target area, in the scanning direction.

[0190] The cycle is the period of movement in the scanning direction during which droplets are ejected from one of the unit regions of the ejection target substrate through one of the nozzles. (3)

[0192] According to the liquid ejection device described in (1) or (2) above, wherein,

[0193] The control unit applies a driving waveform to the piezoelectric element, causing multiple droplets ejected from the nozzle to land at different positions in the scanning direction within the one cycle. (4)

[0195] According to any one of (1) to (3) above, the liquid ejection device, wherein,

[0196] The control unit applies a drive waveform to the piezoelectric element in a manner that adjusts the multiple droplets ejected from the nozzle during the period from ejection to landing within the one cycle. (5)

[0198] According to any one of (1) to (4) above, the liquid ejection device, wherein,

[0199] The control unit applies a driving waveform to the piezoelectric element such that at least one of the ejection velocity and ejection amount of the plurality of droplets ejected from the nozzle is the same among the plurality of droplets in the one cycle. (6)

[0201] According to any one of (1) to (5) above, the liquid ejection device, wherein,

[0202] The control unit applies a drive waveform to the piezoelectric element, adjusting the ejection amount of each of the plurality of droplets in such a way that the thickness of the liquid film formed by the landing of the plurality of droplets ejected from the nozzle in the one cycle becomes the target film thickness. (7)

[0204] A printing method is performed by a liquid ejection device having a liquid ejection head, the liquid ejection head having a nozzle communicating with a pressure chamber and ejecting liquid droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element for changing the pressure inside the pressure chamber via a vibrating plate forming part of the wall of the pressure chamber.

[0205] In the printing method, a driving waveform is applied to the piezoelectric element such that droplets are ejected from the nozzle more than twice in one cycle. (8)

[0207] A liquid ejection procedure is executed by a computer that controls a liquid ejection head, the liquid ejection head comprising a nozzle communicating with a pressure chamber and ejecting liquid droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element that changes the pressure within the pressure chamber via a vibrating plate forming part of the wall of the pressure chamber.

[0208] The liquid ejection procedure includes the following steps: applying a drive waveform to the piezoelectric element such that droplets are ejected from the nozzle more than twice in one cycle.

Claims

1. A liquid ejection device, comprising: A liquid ejector head comprising a nozzle communicating with a pressure chamber and ejecting liquid droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element for changing the pressure within the pressure chamber via a vibrating plate forming part of a wall of the pressure chamber; and The control unit controls the liquid ejection head. in, The control unit applies a drive waveform to the piezoelectric element such that the droplets are ejected from the nozzle more than twice within one cycle.

2. The liquid ejection device according to claim 1, wherein, The liquid ejector head is scanned relative to the ejection target substrate, which has a unit region as the ejection target area, in the scanning direction. The cycle is the period of movement in the scanning direction during which droplets are ejected from one of the unit regions of the ejection target substrate through one of the nozzles.

3. The liquid ejection device according to claim 1, wherein, The control unit applies a driving waveform to the piezoelectric element, causing multiple droplets ejected from the nozzle to land at different positions in the scanning direction within the one cycle.

4. The liquid ejection device according to claim 1, wherein, The control unit applies a drive waveform to the piezoelectric element in a manner that adjusts the multiple droplets ejected from the nozzle during the period from ejection to landing within the one cycle.

5. The liquid ejection device according to claim 1, wherein, The control unit applies a driving waveform to the piezoelectric element such that at least one of the ejection velocity and ejection amount of the plurality of droplets ejected from the nozzle is the same among the plurality of droplets in the one cycle.

6. The liquid ejection device according to claim 1, wherein, The control unit applies a drive waveform to the piezoelectric element, adjusting the ejection amount of each of the plurality of droplets in such a way that the thickness of the liquid film formed by the landing of the plurality of droplets ejected from the nozzle in the one cycle becomes the target film thickness.

7. A printing method performed by a liquid ejection device having a liquid ejection head, the liquid ejection head having a nozzle communicating with a pressure chamber and ejecting droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element for changing the pressure inside the pressure chamber via a vibrating plate forming part of the wall of the pressure chamber. In the printing method, a driving waveform is applied to the piezoelectric element such that droplets are ejected from the nozzle more than twice in one cycle.

8. A storage medium storing a liquid ejection program executed by a computer controlling a liquid ejection head, the liquid ejection head comprising a nozzle communicating with a pressure chamber and ejecting droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element for changing the pressure within the pressure chamber via a vibrating plate forming part of a wall of the pressure chamber. The liquid ejection procedure includes the following steps: A drive waveform is applied to the piezoelectric element such that the droplets are ejected from the nozzle more than twice in one cycle.

9. A computer program product comprising a liquid ejection program executed by a computer controlling a liquid ejection head, the liquid ejection head having a nozzle communicating with a pressure chamber and ejecting droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element for changing the pressure within the pressure chamber via a vibrating plate forming part of a wall of the pressure chamber. The liquid ejection procedure includes the following steps: A drive waveform is applied to the piezoelectric element such that the droplets are ejected from the nozzle more than twice in one cycle.

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