Driving device and liquid ejection head

Abstract

A driving device and a liquid ejection head capable of increasing a driving frequency are provided. The driving device inputs a driving waveform to an actuator of a liquid ejection head having a pressure chamber that contains a liquid, a nozzle plate that is disposed to the pressure chamber and that is formed with nozzles that eject the liquid, a vibrating plate that pressurizes the liquid in the pressure chamber, and the actuator that drives the vibrating plate. The driving waveform includes an ejection pulse that ejects the liquid from the nozzles, a first cancel pulse that cancels residual vibrations caused in the liquid in the pressure chamber by the ejection pulse, and a second cancel pulse that cancels residual vibrations left in the actuator after the input of the first cancel pulse.

Description

Technical Field

[0001] Embodiments of the present invention relate to a driving device and a liquid ejector head. Background Technology

[0002] Piezoelectric liquid ejector heads for ejecting liquids such as ink are known in the past. For example, such liquid ejector heads, as push-type ejector heads, are known to have the following mechanism: a pressure chamber containing ink; a nozzle connected to one end of the pressure chamber for ejecting ink; a supply path connected to the other end of the pressure chamber; a vibrating plate sealing the supply path side of the pressure chamber; and an actuator pressurizing the ink in the pressure chamber via the vibrating plate. The liquid ejector head ejects droplets by inputting a drive waveform generated by a drive device provided in the liquid ejector head and the liquid ejection device equipped with the liquid ejector head to the actuator corresponding to the pressure chamber from which the liquid is ejected.

[0003] For example, the liquid ejector head inputs a drive waveform to the actuator, causing the voltage to rise from the standby voltage and expand the volume of the pressure chamber. Then, it returns to the standby voltage and shrinks the volume, pressurizing the ink in the pressure chamber and ejecting the ink from the nozzle.

[0004] The following hidden dangers exist in such a drive waveform: residual vibration remains in the pressure chamber after the ink is ejected; due to air bubbles being drawn into the meniscus of the nozzle after the ink is ejected, and the influence of the previous ejection action, the ejection speed and ink volume in subsequent ink ejections deviate, thus making it impossible to increase the drive frequency.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2024-100427 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] According to the present invention, a drive device and a liquid ejector head capable of increasing the drive frequency can be provided.

[0010] Solutions for solving technical problems

[0011] The driving device according to the embodiment inputs a driving waveform to the actuator of a liquid ejector head, the liquid ejector head having: a pressure chamber for containing liquid; a nozzle plate disposed in the pressure chamber and forming a nozzle for ejecting liquid; a vibrating plate for pressurizing the liquid in the pressure chamber; and the actuator for driving the vibrating plate. The driving waveform includes: an ejection pulse for ejecting the liquid from the nozzle; a first cancellation pulse for eliminating residual vibrations in the liquid in the pressure chamber caused by the ejection pulse; and a second cancellation pulse for eliminating residual vibrations remaining in the actuator after the input of the first cancellation pulse. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view showing the structure of the liquid ejector head according to the embodiment.

[0013] Figure 2 This is an explanatory diagram showing an example of the structure of the drive device for the liquid ejector head according to the embodiment.

[0014] Figure 3 These are explanatory diagrams illustrating other examples of the structure of the drive device involved in the embodiments.

[0015] Figure 4 This is an explanatory diagram showing an example of the drive waveform and flow velocity vibration of the liquid ejector head according to the embodiment.

[0016] Figure 5 This is an explanatory diagram showing an example of the driving waveform and flow velocity vibration of the liquid ejector head involved in the comparative example.

[0017] Explanation of reference numerals in the attached figures

[0018] 1…Liquid nozzle, 10…Actuator, 11…Piezoelectric element, 12…Electrode, 12…Independent electrode, 13…Electrode, 13…Common electrode, 20…Vibrating plate, 20a…Opening, 30…Flow path component, 30a…Upper common flow path, 30b…Upper independent flow path, 30c…Pressure chamber, 30d…Lower independent flow path, 30e…Lower common flow path, 31…Lower body, 31a…First through hole, 31b…Groove, 31c…Second through hole, 32…Nozzle plate, 32a…Nozzle, 33… Flow path plate, 33a… third through hole, 33b… pressure chamber end hole, 33c… flow path hole, 34… upper body, 34a… groove, 34b… opening, 50… drive device, 51… anisotropic conductive component, 52… wiring board, 53… connector, 55… waveform generation circuit, 56… waveform amplification circuit, 57… waveform selection circuit, 58… control circuit, 59… analog switch, P1… ejection pulse, P2… first cancellation pulse, P3… second cancellation pulse, V… flow velocity vibration, W… drive waveform. Detailed Implementation

[0019] The following is for reference Figures 1 to 5 The liquid ejector head 1 and the drive device 50 involved in the embodiment will be described. Figure 1 This is a cross-sectional view that briefly shows the structure of the liquid ejector head 1 according to the embodiment. Figure 2 This is an explanatory diagram showing an example of the structure of the drive device 50 for the liquid ejector head 1. Figure 3 This is an illustrative diagram showing another example of the structure of the drive unit 50. Figure 4 This is an explanatory diagram showing an example of the drive waveform and flow velocity vibration of the liquid ejector head 1 according to the embodiment. Figure 5 This is an explanatory diagram showing an example of the drive waveform and flow velocity vibration of the liquid ejector head involved in the comparative example. It should be noted that, in this embodiment, the nozzle plate 32 side of the liquid ejector head 1 is designated as the lower side, and the upper body 34 side is designated as the upper side, to define the vertical direction, which will be explained below.

[0020] The liquid ejector head 1 is, for example, a push-type ink ejector head that ejects ink as a liquid onto a recording medium such as paper. The liquid ejector head 1 is installed in a liquid ejection device such as an inkjet recording device.

[0021] Ink stored in a supply tank provided in the liquid ejection device is supplied to the liquid ejection head 1. It should be noted that the liquid ejection head 1 is a circulating head that circulates the ink, but it can also be a non-circulating head that does not circulate the ink.

[0022] like Figure 1 As shown, the liquid ejector head 1 includes, for example, an actuator 10, a vibrating plate 20, a flow path component 30, and a drive device 50. The liquid ejector head 1 drives the actuator 10, which is driven by a drive waveform W generated by the drive device 50, to vibrate the vibrating plate 20 and change the volume of the pressure chamber 30c, thereby ejecting the ink contained in the pressure chamber 30c from the nozzle 32a.

[0023] The actuator 10 includes, for example, a plurality of piezoelectric elements 11 formed by stacking piezoelectric components such as PZT, a plurality of independent electrodes 12 respectively disposed on each piezoelectric element 11, and a single or multiple common electrodes 13 disposed on the plurality of piezoelectric elements 11.

[0024] Multiple piezoelectric elements 11 are arranged, for example, along one direction and fixed to the vibrating plate 20 and the flow path component 30. The multiple piezoelectric elements 11 are, for example, configured to face, across the vibrating plate 20, multiple pressure chambers 30c formed in the flow path component 30.

[0025] The piezoelectric element 11 deforms by applying a voltage to the individual electrode 12 or the common electrode 13 via the drive device 50. In the piezoelectric element 11, for example, multiple piezoelectric components are stacked laterally. When an electric field is applied, it deforms in a direction orthogonal to the stacking direction of the multiple piezoelectric components, causing the vibrating plate 20 to deform. That is, the piezoelectric element 11 deforms in the d31 mode. The electrodes 12 and 13 formed on each piezoelectric element 11 are connected to the control unit of the liquid ejection device via the drive device 50 (drive circuit) and are configured to be controllable by the control unit. When a predetermined voltage is input, the piezoelectric element 11 expands and contracts according to the voltage value. For example, when a reference voltage is input, the piezoelectric element 11 is in a standby state without deformation; if a voltage lower than the reference voltage is applied, it stretches in a direction orthogonal to the stacking direction of the piezoelectric components; and if a voltage higher than the reference voltage is applied, it contracts in a direction orthogonal to the stacking direction of the piezoelectric components.

[0026] The actuator 10 can also be configured to deform the piezoelectric element 11 in the d33 mode. In the d33 mode, the piezoelectric components are stacked longitudinally, and when an electric field is applied, they deform along the stacking direction, causing the vibrating plate 20 to deform. In the d33 mode, if a voltage higher than the reference voltage is applied, the piezoelectric components are stretched in the stacking direction, and if a voltage lower than the reference voltage is applied, the piezoelectric components are contracted in the stacking direction.

[0027] In this embodiment, an example is described where the piezoelectric element 11 is in d31 mode, that is, it stretches when a voltage lower than the reference voltage is applied, and contracts when a voltage higher than the reference voltage is applied.

[0028] Multiple independent electrodes 12 are formed on each of the multiple piezoelectric elements 11. Each of the multiple independent electrodes 12 is electrically connected to each of the multiple piezoelectric elements 11.

[0029] The common electrode 13 provides a common electrical connection among the multiple piezoelectric elements 11. For example, there may be one common electrode 13, which is electrically connected to all of the multiple piezoelectric elements 11. It should be noted that there may also be multiple common electrodes 13, each of which electrically connects several of the multiple piezoelectric elements 11 to each other.

[0030] Multiple piezoelectric elements 11 are fixed to the vibrating plate 20. The vibrating plate 20 deforms with the extension and retraction of the actuator 10. The vibrating plate 20 is, for example, a metal plate. The vibrating plate 20 extends along a plane orthogonal to the vibration direction, i.e., the extension and retraction direction of the actuator 10 fixed to the vibrating plate 20. The vibrating plate 20 is engaged with the multiple piezoelectric elements 11 and supported by the flow path component 30. For example, the vibrating plate 20 deforms due to the displacement of the vibrating portion engaged with the piezoelectric elements 11 by the extension and retraction of the piezoelectric elements 11. For example, the vibrating plate 20 is fixed between the flow path plate 33 (described later) and the upper body 34 of the flow path component 30, and the area where the actuator 10 is fixed is exposed from a part of the upper body 34. For example, multiple openings 20a are formed in the vibrating plate 20, which are configured to face the upper common flow path 30a (described later) of the flow path component 30 and each of the multiple upper independent flow paths 30b. For example, the vibrating plate 20 is formed as a rectangular plate that is longer in one direction, and a plurality of piezoelectric elements 11 and a plurality of openings 20a are arranged at predetermined intervals along the long side.

[0031] The flow path component 30 includes a lower body 31, a nozzle plate 32, a flow path plate 33, and an upper body 34. The flow path component 30 holds the actuator 10 and the vibrating plate 20. In addition, the flow path component 30 forms an upper common flow path 30a, a plurality of upper independent flow paths 30b connected to the upper common flow path 30a, a plurality of pressure chambers 30c connected to the plurality of upper independent flow paths 30b, a plurality of lower independent flow paths 30d connected to the plurality of pressure chambers 30c, and a lower common flow path 30e connected to the plurality of lower independent flow paths 30d through the lower body 31, nozzle plate 32, flow path plate 33, and upper body 34.

[0032] The lower body 31 is, for example, formed as a rectangular plate that extends in one direction. The lower body 31 has, for example, a nozzle plate 32 fixed to the lower main surface of its two main surfaces in the vertical direction, and a flow path plate 33 fixed to the upper main surface. The lower body 31 includes: a plurality of first through holes 31a forming a plurality of pressure chambers 30c; a plurality of grooves 31b formed on the lower main surface forming a plurality of lower independent flow paths 30d; and a second through hole 31c forming a lower common flow path 30e. Additionally, the lower body 31 has an ink port for supplying or discharging ink to the lower common flow path 30e.

[0033] A plurality of first through holes 31a are formed and arranged at predetermined intervals along the long side of the lower body 31. The arrangement direction of the plurality of first through holes 31a (a plurality of pressure chambers 30c) is the same as the arrangement direction of the plurality of piezoelectric elements 11. A plurality of slots 31b are provided in the same number as the plurality of first through holes 31a (a plurality of pressure chambers 30c). For example, the plurality of slots 31b are formed to extend along the short side of the lower body 31 and are arranged at predetermined intervals along the long side of the lower body 31. One end of each slot 31b is continuous with each first through hole 31a, and the other end is continuous with a second through hole 31c.

[0034] The nozzle plate 32 is fixed to the lower main surface of the lower body 31, covering at least a plurality of first through holes 31a, a plurality of slots 31b, and a second through hole 31c of the lower body 31. The nozzle plate 32 is, for example, formed as a rectangular plate elongated in one direction, having the same shape as the lower main surface of the lower body 31. A plurality of nozzles 32a are formed on the nozzle plate 32, positioned opposite to the plurality of first through holes 31a. As an example, the plurality of nozzles 32a are arranged along the long side of the nozzle plate 32. In other words, the arrangement direction of the plurality of nozzles 32a is, for example, the same as the arrangement direction of the plurality of first through holes 31a (the plurality of pressure chambers 30c) and the plurality of piezoelectric elements 11.

[0035] The flow path plate 33 is fixed to the upper main surface of the lower body 31, covering at least a plurality of first through holes 31a and second through holes 31c of the lower body 31. The flow path plate 33 is, for example, formed as a rectangular plate that elongates in one direction, having the same shape as the upper main surface of the lower body 31. For example, the lower main surface of the flow path plate 33 is fixed to the lower body 31, and the vibrating plate 20 is fixed to the upper main surface. A plurality of third through holes 33a are formed in the flow path plate 33, forming a plurality of upper independent flow paths 30b.

[0036] Multiple third through holes 33a are, for example, formed to be arranged at predetermined intervals along the long side of the flow path plate 33. For example, each third through hole 33a includes: a pressure chamber end hole 33b forming the upper end of the pressure chamber 30c; and a flow path hole 33c, one end of which is disposed opposite a portion of the upper common flow path 30a, and the other end of which is continuous with the pressure chamber 30c (pressure chamber end hole 33b). The pressure chamber end hole 33b is continuous with the upper end of the first through hole 31a. For example, the opening area of ​​the pressure chamber end hole 33b is formed to be larger than the opening area of ​​the first through hole 31a in the lower body 31.

[0037] One end of each flow path hole 33c is configured to face each opening 20a of the vibrating plate 20. The flow path holes 33c and the openings 20a of the vibrating plate 20 together form an upper independent flow path 30b.

[0038] The upper body 34 is fixed to the upper main surface of the vibrating plate 20. The upper body 34 has a groove 34a forming an upper common flow path 30a, and multiple openings 34b formed in the region of the vibrating plate 20 where the actuator 10 is disposed. The groove 34a opens on the lower main surface of the upper body 34. The openings 34b are, for example, through holes. The multiple openings 34b are positioned opposite to multiple pressure chambers 30c across the vibrating plate 20. The opening shape of the openings 34b is, for example, the same shape as the opening shape of the upper end (pressure chamber end hole 33b) of the pressure chamber 30c. The actuator 10 is engaged with the position corresponding to the pressure chamber 30c via the vibrating plate 20 in the upper body 34. The wiring board 52 of the drive device 50 (described later) is, for example, fixed in the upper body 34. Additionally, an ink port for supplying or discharging ink to the upper common flow path 30a is formed in the upper body 34.

[0039] The lower body 31, nozzle plate 32, flow path plate 33, and upper body 34 of such flow path component 30 combine the vibrating plate 20 between the flow path plate 33 and the upper body 34 to form a fluidly continuous upper common flow path 30a, multiple upper independent flow paths 30b, multiple pressure chambers 30c, multiple lower independent flow paths 30d, and lower common flow path 30e.

[0040] As a specific example, the vibrating plate 20 is joined to the lower main surface of the upper body 34, and the lower end of the groove 34a of the upper body 34 is covered by the vibrating plate 20, thereby forming an upper common flow path 30a that opens at a plurality of openings 20a in the vibrating plate 20. For example, the upper common flow path 30a constitutes a common supply flow path, but it can also be a common discharge flow path.

[0041] As a specific example, the vibrating plate 20 and the lower body 31 are joined to the upper and lower main surfaces of the flow path plate 33, thereby forming multiple upper independent flow paths 30b through the multiple openings 20a of the vibrating plate 20 and the multiple flow path holes 33c of the flow path plate 33. Specifically, the multiple flow path holes 33c of the flow path plate 33 are covered by the vibrating plate 20 and the lower body 31 in the vertical direction, and the ends of the multiple flow path holes 33c are configured to face the multiple openings 20a of the vibrating plate 20, thereby forming multiple upper independent flow paths 30b that make the upper common flow path 30a and the multiple pressure chambers 30c continuous.

[0042] As a specific example, the nozzle plate 32 and the flow path plate 33 are joined to the upper and lower main surfaces of the lower body 31, and the vibrating plate 20 is joined to the upper main surface of the flow path plate 33, thereby forming a plurality of pressure chambers 30c. Specifically, the lower ends of the plurality of first through holes 31a of the lower body 31 are covered by the nozzle plate 32. In addition, the upper ends of the plurality of first through holes 31a are continuous with the lower ends of the plurality of pressure chamber end holes 33b of the flow path plate 33, and the upper ends of the plurality of pressure chamber end holes 33b are covered by the vibrating plate 20. Thus, the plurality of nozzles 32a of the nozzle plate 32 are respectively arranged to form a plurality of pressure chambers 30c for containing ink.

[0043] As a specific example, the nozzle plate 32 is joined to the lower main surface of the lower body 31, and the multiple grooves 31b formed on the lower main surface of the lower body 31 are covered by the nozzle plate 32, thereby forming multiple lower independent flow paths 30d.

[0044] As a specific example, the nozzle plate 32 and the flow path plate 33 are joined to the upper and lower main surfaces of the lower body 31, and the upper and lower ends of the second through hole 31c are covered by the nozzle plate 32 and the flow path plate 33, thereby forming a lower common flow path 30e that is continuous with multiple lower independent flow paths 30d. The lower common flow path 30e constitutes a common discharge flow path, but it can also be a common supply flow path.

[0045] If ink is injected into such a flow path component 30 from the ink port of the upper body 34, which serves as an ink supply port, ink is filled into multiple pressure chambers 30c through each of the multiple upper independent flow paths 30b via the upper common flow path 30a, and discharged from the ink port of the lower body 31, which serves as an ink discharge port, via the multiple lower independent flow paths 30d and the lower common flow path 30e.

[0046] The drive unit 50 includes, for example, an anisotropic conductive component 51, a wiring substrate 52, and a connector 53. The drive unit 50 is a drive circuit for driving the actuator 10. The anisotropic conductive component 51 electrically connects, for example, a plurality of individual electrodes 12 of the actuator 10 and a common electrode 13 to the wiring substrate 52. Alternatively, the common electrode 13 may also be electrically connected to the wiring substrate 52 via other conductive components without passing through the anisotropic conductive component 51.

[0047] Wiring board 52 includes, for example, a driver IC, including various circuits required for driving actuator 10. Wiring board 52 inputs a driving voltage (driving waveform) to each electrode 12, 13 of piezoelectric element 11, thereby driving piezoelectric element 11, increasing or decreasing the volume of pressure chamber 30c, and causing droplets to be ejected from nozzle 32a. Wiring board 52 generates control signals and drive signals for controlling each piezoelectric element 11, such as the timing for selecting the liquid ejection and the signal for the piezoelectric element 11 ejecting the liquid, based on the image signal input from the control unit of the liquid ejection device. For example, the driver IC includes a data buffer, a decoder, and a driver, and is connected to the control unit of the liquid ejection device via connector 53.

[0048] Alternatively, the wiring substrate 52 may not have a driver IC, and the individual electrodes 12 and the common electrode 13 of the actuator 10 may be directly electrically connected to the connector 53. The connector 53, for example, has multiple terminals that are independently electrically connected to each of the multiple individual electrodes 12 and the common electrode 13 via anisotropic conductive members 51 and the wiring substrate 52. The connector 53 may be configured to be connected to a cable, for example, and is separate from the liquid nozzle 1, but electrically connected to the drive unit 50 of the liquid dispensing device.

[0049] Such a drive device 50 selectively drives the actuator 10 corresponding to the pressure chamber 30c from which the ink is ejected, based on image signals. As a specific example, such as... Figure 2 As shown, the driving device 50 includes a waveform generation circuit 55, a waveform amplification circuit 56, and a waveform selection circuit 57.

[0050] Waveform generation circuit 55 generates a pre-defined driving waveform W and inputs it to waveform amplification circuit 56. Waveform amplification circuit 56 amplifies the driving waveform W and inputs the amplified driving waveform W to waveform selection circuit 57.

[0051] The waveform selection circuit 57 includes, for example, a control circuit 58 and multiple analog switches 59. The control circuit 58 controls the switching of the analog switches 59 between ON and OFF states based on the image signal. The ON channel inputs a driving waveform W to the actuator 10. The OFF channel becomes a high impedance, and the actuator 10 is not driven. That is, the control circuit 58 sets the analog switch 59 corresponding to the actuator 10, which is selectively driven based on the image signal, to ON. Figure 2 In this example, the analog switch 59 of the waveform selection circuit 57 is located on the side of multiple independent electrodes 12, and the driving waveform W is applied to the independent electrode 12 of the selected actuator 10. It should be noted that... Figure 3 Other examples of drive unit 50 (drive circuit) are shown below. Figure 3In the example, the driving waveform W is applied to the common electrode 13 side. By turning on the analog switch 59 in the independent electrode 12 corresponding to the driven actuator 10, the independent electrode 12 is grounded, and the selected actuator 10 is driven. Alternatively, by turning off the analog switch 59 that does not correspond to the driven actuator 10, the independent electrode 12 of the non-driven actuator 10 becomes high impedance, the potential of the independent electrode 12 becomes the same as that of the common electrode 13, and the actuator 10 is not driven.

[0052] In this liquid ejector head 1, the liquid ejector head is in a standby state where ink is filled into the flow path component 30, and the pressure at the ink supply port and ink discharge port is controlled to a slightly negative pressure relative to atmospheric pressure at appropriate values. Furthermore, if a drive waveform W is applied from the drive device 50 to the actuator 10, the actuator 10 extends and retracts, causing the vibrating plate 20 to vibrate. When the vibrating plate 20 vibrates, the pressure in the pressure chamber 30c changes, and ink is ejected from the nozzle 32a.

[0053] In the push-type liquid ejector head 1 with the above-described structure, the movable part of the actuator 10 has a natural vibration frequency that is close to the natural vibration frequency of the ink fluid within the pressure chamber 30c. Therefore, the residual vibration of the ink within the pressure chamber 30c is influenced by both the residual vibration of the ink fluid itself and the residual vibration of the actuator 10 structure.

[0054] Next, use Figure 4 The structure of the drive waveform W input from the drive device 50 (drive circuit) will be described. Furthermore, as a comparative example comparing the drive waveform W with that of this embodiment, in... Figure 5 The structure of the driving waveform W0 involved in the comparative example is explained below.

[0055] It should be noted that, Figure 4 (a) and Figure 5 (a) shows the driving waveforms W and W0, with the vertical axis representing voltage and the horizontal axis representing time. Additionally, in Figure 4 (a) and Figure 5 In (a), the standby voltage is shown by a dashed line, and the drive waveforms W and W0 are shown by solid lines. In the examples of drive waveform W in this embodiment and drive waveform W0 in the comparative example, the following example is shown: if a voltage higher than the standby voltage is applied, the actuator 10 contracts and the volume of the pressure chamber 30c expands; and if a voltage lower than the standby voltage is applied, the actuator 10 extends and the volume of the pressure chamber 30c contracts.

[0056] It should be noted that, in cases where the actuator 10 is configured in the d33 mode, it can also be configured such that if a voltage higher than the standby voltage is applied, the actuator 10 extends and the volume of the pressure chamber 30c contracts; and if a voltage lower than the standby voltage is applied, the actuator 10 contracts and the volume of the pressure chamber 30c expands. In this case, Figure 4 The driving waveform W of (a) is symmetrical about the standby voltage and becomes a shape that is reversed up and down.

[0057] in addition, Figure 4 (b) and Figure 5 (b) shows the velocity vibrations V and V0 generated at the ink meniscus of nozzle 32a when drive waveforms W and W0 are applied, with the vertical axis representing velocity and the horizontal axis representing time. The velocity vibrations at the ink meniscus of nozzle 32a reflect the fluid vibrations of the ink within pressure chamber 30c. Thus, the state without velocity vibrations at the ink meniscus of nozzle 32a can be considered as a state without residual vibrations of the ink within pressure chamber 30c.

[0058] Such flow velocity vibration can be measured by irradiating the ink concave surface of the ink in the nozzle 32a with a laser from a laser Doppler vibrometer when the voltage amplitude of the driving waveform W is sufficiently reduced to the point that the ink will not be ejected from the nozzle 32a.

[0059] like Figure 4 As shown in (a), the drive waveform W includes: an ejection pulse P1 that ejects ink; a first cancellation pulse P2 that eliminates residual vibrations of ink generated in the pressure chamber 30c due to the ejection action of the ejection pulse P1; and a second cancellation pulse P3 that eliminates residual vibrations remaining in the actuator 10 after the input of the first cancellation pulse P2.

[0060] The voltage change of the ejection pulse P1 starts from the standby voltage, changes to a voltage higher than the standby voltage that causes the volume of the pressure chamber 30c (hereinafter simply referred to as the volume), and ends at a voltage higher than the standby voltage that causes the volume to contract. Thus, the volume contracts after expansion, the ink in the pressure chamber 30c is pressurized, and the ink is ejected from the nozzle 32a.

[0061] The voltage change of the first cancellation pulse P2 begins at a voltage that causes volume expansion compared to the end voltage of the ejection pulse P1, changes to a voltage that causes volume contraction compared to the standby voltage, and then ends at a voltage that causes volume expansion compared to the standby voltage. In other words, the voltage change of the first cancellation pulse P2 begins at a voltage that causes volume contraction, which is closer to the standby voltage than the end voltage of the ejection pulse P1, changes to a voltage that causes volume contraction—that is, a voltage lower than the voltage that causes volume contraction at the beginning of the first cancellation pulse P2, for example, a voltage lower than the end voltage of the ejection pulse P1—and then ends at a voltage that causes volume expansion compared to the standby voltage. Through the first cancellation pulse P2, as... Figure 4 As shown in (b) flow velocity vibration V, the residual vibration of the ink in pressure chamber 30c is eliminated. It should be noted that the volume of the voltage at the end of the ejection pulse P1 is less than the volume of the standby voltage, and the volume of the voltage at the beginning of the first cancellation pulse P2 is greater than the volume of the voltage at the end of the ejection pulse P1. Therefore, after the ejection pulse P1 ends and before the first cancellation pulse P2 begins, the voltage applied to actuator 10 changes towards the direction of volume expansion.

[0062] The voltage change of the second cancellation pulse P3 starts from the end voltage of the first cancellation pulse P2, changes to a voltage that causes the volume to shrink compared to the standby voltage, and then ends at the standby voltage. For example, the second cancellation pulse P3 is input continuously with the first cancellation pulse P2. In addition, the voltage change of the second cancellation pulse P3 that causes the volume to shrink is performed multiple times as needed.

[0063] like Figure 4 As shown in (b) regarding the flow velocity vibration V, when the second cancellation pulse P3 is applied, the state after the flow velocity vibration was eliminated by the first cancellation pulse P2 is maintained. That is, the driving force generated in the actuator 10 by the second cancellation pulse P3 does not accompany the volume change of the pressure chamber 30c, thus eliminating the vibration energy remaining in the actuator 10.

[0064] By using such a driving waveform W, the residual vibration of the ink in the pressure chamber 30c is eliminated by the first cancellation pulse P2, and the residual vibration remaining in the actuator 10 is eliminated by the second cancellation pulse P3. Thus, the residual vibrations of both the ink in the pressure chamber 30c and the actuator 10 are eliminated. Therefore, the liquid ejector head 1 can achieve a high driving frequency. Here, driving frequency means the number of ink droplets ejected per unit time (the number of ink droplet ejections). It should be noted that the voltage and time of the ejection pulse P1, the first cancellation pulse P2, and the second cancellation pulse P3 can be appropriately set if they can reduce the residual vibrations generated in the ink in the pressure chamber 30c and in the actuator 10.

[0065] In contrast, such as Figure 5 As shown in (a), the comparative example's drive waveform W0 includes: an ejection pulse P10, ejecting ink; and a cancellation pulse P20, eliminating residual vibrations generated in the pressure chamber 30c due to the ejection action of the ejection pulse P10. The voltage change of the ejection pulse P10 starts from the standby voltage, changes to a voltage that expands the volume compared to the standby voltage, and then ends at the standby voltage. The cancellation pulse P20 starts from the standby voltage, changes to a voltage that contracts the volume compared to the standby voltage, and then ends at the standby voltage. Although the cancellation pulse P20 reduces the residual vibrations generated by the ejection pulse P10, it cannot eliminate the residual vibrations of both the ink and the actuator 10 in the pressure chamber 30c, such as... Figure 5As shown in (b) of the flow velocity vibration V0, residual vibration remains even after the input of pulse P20 is removed, indicating that the residual vibration is not fully eliminated. Therefore, it can be concluded that a high driving frequency cannot be achieved when the driving waveform W0 is applied to the liquid ejector head 1.

[0066] As described above, the liquid ejector head 1 inputs the drive waveform W input to the actuator 10 via the drive device 50 after the input of the ejection pulse P1, and then inputs the first cancellation pulse P2 and the second cancellation pulse P3 to eliminate residual vibration, thereby increasing the drive frequency.

[0067] It should be noted that the embodiments of the present invention are not limited to the structures described above. For example, a structure in which the drive device 50 is disposed in the liquid nozzle 1 has been described. Thus, the drive device 50 (drive circuit) can be any structure that generates a drive waveform W and can be input to the actuator 10, and the structure and configuration are not limited. For example, the drive device 50 may also be disposed separately from the liquid nozzle 1, or a portion of the drive device 50 (a portion of the drive circuit) may be disposed in the liquid nozzle 1, and the remaining portion of the drive device 50 (the remaining portion of the drive circuit) may be disposed in the liquid dispensing device equipped with the liquid nozzle 1. In addition, when it is not necessary to selectively drive the actuator 10, but to drive all the actuators 10 simultaneously, the waveform selection circuit 57 may be omitted.

[0068] Furthermore, while the above example illustrates one instance of the flow path component 30, the structure of the flow path component 30 can be appropriately configured if a flow path capable of supplying ink to the pressure chamber 30c can be formed. For example, in the above example, an example was described where multiple upper independent flow paths 30b are formed by multiple openings 20a of the vibrating plate 20 and multiple flow path holes 33c of the flow path plate 33. Thus, the opening 20a of the vibrating plate 20 can also be configured as a single hole that extends in one direction and is continuous with the multiple flow path holes 33c. Additionally, for example, the vibrating plate 20 can also be configured to be provided only in the region opposite to the actuator 10 and the pressure chamber 30c.

[0069] The liquid ejector head described above, by including an ejection pulse, a first cancellation pulse, and a second cancellation pulse in the drive waveform, can increase the drive frequency.

[0070] While several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a wide variety of other ways, with various omissions, substitutions, and modifications possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are encompassed by the scope of the claims and their equivalents.

Claims

1. A driving device, characterized in that, The driving device inputs a driving waveform to the actuator of the liquid nozzle, the liquid nozzle having: a pressure chamber for containing liquid; A nozzle plate, disposed in the pressure chamber, forms a nozzle for ejecting the liquid; A vibrating plate pressurizes the liquid within the pressure chamber; And the actuator drives the vibrating plate. In the drive device, The drive waveform includes: an ejection pulse that ejects the liquid from the nozzle; a first cancellation pulse that eliminates residual vibrations in the liquid within the pressure chamber caused by the ejection pulse; and a second cancellation pulse that eliminates residual vibrations remaining in the actuator after the input of the first cancellation pulse.

2. The driving device according to claim 1, characterized in that, When the second cancellation pulse is applied, the flow rate vibration of the liquid in the nozzle is maintained in the state after it has been eliminated.

3. The driving device according to claim 1, characterized in that, The voltage change of the ejected pulse begins at the standby voltage, changes to a voltage higher than the standby voltage that causes the volume of the pressure chamber to expand, and then ends at a voltage higher than the standby voltage that causes the volume to contract. The voltage change of the first cancellation pulse begins at a voltage higher than the end voltage of the ejection pulse that causes the volume to expand, changes to a voltage higher than the standby voltage that causes the volume to contract, and then ends at a voltage higher than the standby voltage that causes the volume to expand. The voltage change of the second cancellation pulse starts from the end voltage of the first cancellation pulse, changes to a voltage that causes the volume to shrink compared to the standby voltage, and then ends at the standby voltage.

4. A liquid ejector head, characterized in that, have: A flow path component includes a pressure chamber and a nozzle plate, the pressure chamber containing liquid and the nozzle plate disposed in the pressure chamber to form a nozzle for ejecting ink; A vibrating plate pressurizes the liquid within the pressure chamber; Actuator, drives the vibrating plate; as well as The driving device according to any one of claims 1 to 3.

Images