Liquid dispensing device

Abstract

To provide a liquid discharge device that can suppress liquid discharge characteristics from varying, without putting a limit on pressure to be applied to an individual liquid chamber.SOLUTION: A liquid discharge device according to one aspect of the present invention comprises: at least one first individual liquid chamber provided with a nozzle that discharges liquid; at least one second individual liquid chamber which is not provided with the nozzle; vibration plates with flexibility provided in the first and the second individual liquid chambers respectively; a pressure varying member that deforms the vibration plates in response to a driving signal so as to vary respective internal pressure in the first and the second individual liquid chambers; common liquid chambers or common flow paths communicating with the first and the second individual liquid chambers respectively; and a driving part that drives the pressure varying member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, liquid ejection devices have been known that have individual liquid chambers each provided with a nozzle for ejecting liquid, and eject liquid from the nozzle by outputting a drive signal to the individual liquid chamber to change the pressure within the individual liquid chamber.

[0003] As such a liquid ejection device, a configuration has been disclosed in which, in order to suppress fluctuations in liquid ejection characteristics, the liquid in an individual liquid chamber in which at least one pause nozzle that does not eject liquid is provided around the ejection nozzle is pressurized to a level that prevents the liquid from being ejected, at a timing earlier than the timing at which the ejection nozzle ejects liquid (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, depending on the pressure applied to the individual liquid chamber in which the inactive nozzle is provided, unnecessary liquid may be ejected from the inactive nozzle, so there is room for improvement in that the pressure applied to the individual liquid chamber is limited.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejection device that is capable of suppressing fluctuations in liquid ejection characteristics without restricting the pressure applied to individual liquid chambers. [Means for solving the problem]

[0006] A liquid ejection device according to one aspect of the present invention includes at least one first individual liquid chamber provided with a nozzle for ejecting liquid, at least one second individual liquid chamber not provided with the nozzle, flexible vibration plates provided in the first and second individual liquid chambers, a pressure variable member that changes the internal pressure of each of the first and second individual liquid chambers by deforming the vibration plate in response to a drive signal, a common liquid chamber or a common flow path that communicates with each of the first and second individual liquid chambers, and a drive unit that drives the pressure variable member. The driving unit changes the number of the second individual liquid chambers for driving the pressure variable member in accordance with the number of the first individual liquid chambers for driving the pressure variable member. . [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a liquid ejection device that can suppress fluctuations in liquid ejection characteristics without restricting the pressure applied to the individual liquid chambers. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an example of the configuration of a liquid ejection device according to an embodiment. [Figure 2] FIG. 1 is a first diagram illustrating the operation of the liquid ejection device according to the embodiment. [Figure 3] FIG. 2 is a second diagram illustrating the operation of the liquid ejection device according to the embodiment. [Figure 4] 5A and 5B are diagrams illustrating an example of a drive signal from a drive circuit according to the first embodiment. [Figure 5] 10A and 10B are diagrams illustrating an example of a drive signal from a drive circuit according to a second embodiment. [Figure 6] 10A and 10B are diagrams illustrating an example of a drive signal from a drive circuit according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0010] [Embodiment] The liquid ejection device 1 according to the embodiment is used for various purposes, such as an image forming device that ejects ink to form an image on paper, or a three-dimensional modeling device that ejects modeling liquid onto a powder layer formed by forming a layer of powder in order to form a three-dimensional object. The liquid ejection device 1 visualizes meaningful images such as letters and figures using the ejected liquid, and also includes devices that form patterns that do not have meaning in themselves and devices that form three-dimensional images.

[0011] The ink ejected by the liquid ejection device 1 adheres to an object onto which the ink can adhere. An object onto which the ink can adhere means an object onto which the ink can adhere at least temporarily, such as an object onto which the ink can adhere and stick, or an object onto which the ink can penetrate. Specific examples include recording media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells. The material onto which the ink can adhere may be any material to which the ink can adhere, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like, as long as the ink can adhere, even if only temporarily.

[0012] The ink ejected from the liquid ejection device 1 is one example of a liquid ejected from a nozzle. The liquid may have a viscosity and surface tension that allows it to be ejected from the liquid ejection device 1. While there are no particular limitations on the liquid, it is preferable for the viscosity of the liquid to be 30 mPa·s or less at room temperature and pressure, or upon heating or cooling. More specifically, the liquid may include solvents such as water or organic solvents, colorants such as dyes or pigments, polymerizable compounds, resins, surfactants, and other functional materials. Alternatively, the liquid may include solutions, suspensions, emulsions, and the like containing biocompatible materials such as DNA, amino acids, proteins, or calcium, or edible materials such as natural pigments. These liquids are used, for example, in inkjet inks, surface treatment solutions, liquids for forming components of electronic devices or light-emitting elements, resist patterns for electronic circuits, and material liquids for 3D modeling.

[0013] Other examples of liquid ejection devices 1 include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that sprays a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0014] <Configuration example of liquid ejection device 1> 1 is a cross-sectional view illustrating the configuration of a liquid ejection device 1. The liquid ejection device 1 has at least one first individual liquid chamber 11a, at least one second individual liquid chamber 11b, a vibration plate 13, a pressure variable member 14, a common liquid chamber 15, and a drive circuit 2.

[0015] The common liquid chamber 15 is a rectangular box-like structure whose longitudinal direction is the direction in which the plurality of first individual liquid chambers 11a and the plurality of second individual liquid chambers 11b are arranged and whose six sides are surrounded by faces. The common liquid chamber 15 can also be called a common flow path, from the viewpoint that it is a flow path through which ink flows, separate from the individual liquid chambers.

[0016] The common liquid chamber 15 can be made of a metal material such as stainless steel. The common liquid chamber 15 contains the ink 5 that flows from the common liquid chamber 15 through the flow path 12. The common liquid chamber 15 has a supply port 151 and a discharge port 152 on one side.

[0017] The common liquid chamber 15 is connected to a supply tube 41 via a supply port 151, and ink 5 is supplied through the supply tube 41 from an ink tank or the like that stores ink 5. The common liquid chamber 15 is also connected to a discharge tube 42 via a discharge port 152. When discharging ink 5 from the common liquid chamber 15, the liquid ejection device 1 can discharge the ink 5 in the common liquid chamber 15 through the discharge tube 42 after the stopper 3 is opened. For example, when the liquid ejection device 1 is connected to a circulation mechanism that circulates ink 5 between the ink tank and the liquid ejection device 1, the ink 5 circulated by the circulation mechanism can be supplied from the supply port 151 and discharged from the discharge port 152.

[0018] The first individual liquid chamber 11a and the second individual liquid chamber 11b are each connected to a common liquid chamber 15 through a flow channel 12. The ink 5 in the common liquid chamber 15 can flow through the flow channel 12 into each of the first individual liquid chamber 11a and the second individual liquid chamber 11b.

[0019] In this embodiment, the liquid ejection device 1 has five first individual liquid chambers 11a arranged in a row, and a total of six second individual liquid chambers 11b arranged outside the ends of the first individual liquid chambers 11a in the direction in which the first individual liquid chambers 11a are arranged. However, the number and arrangement of the first individual liquid chambers 11a and second individual liquid chambers 11b are not limited to those described above, and can be selected appropriately depending on the application of the liquid ejection device 1, etc.

[0020] Each of the first individual liquid chamber 11a and the second individual liquid chamber 11b is a rectangular box-like structure surrounded by faces on all six sides, and can accommodate ink flowing in from the common liquid chamber 15 through the flow path 12. The multiple first individual liquid chambers 11a and the multiple second individual liquid chambers 11b are integrally formed using a metal material such as stainless steel.

[0021] The first individual liquid chamber 11a has a nozzle 110 on one surface thereof for ejecting ink. The nozzle 110 is a through-hole formed on the one surface. The shape of the through-hole of the nozzle 110 is, for example, a substantially perfect circle, but is not limited to this and may be any shape such as a substantially ellipse, a substantially rectangular shape, or a substantially polygonal shape.

[0022] The nozzle 110 ejects the ink stored in the first individual liquid chamber 11a through the nozzle 110 toward the outside of the first individual liquid chamber 11a in response to the pressure applied to the inside of the first individual liquid chamber 11a.

[0023] On the other hand, the second individual liquid chamber 11b does not have a nozzle 110 for ejecting ink. Therefore, when pressure is applied to the ink contained in the second individual liquid chamber 11b, this pressure is transmitted to the common liquid chamber 15 side through the flow path 12.

[0024] The diaphragm 13 is a flexible plate-like member, and is provided between the first individual liquid chamber 11a and the second individual liquid chamber 11b and the common liquid chamber 15 so as to form pairs with the first individual liquid chamber 11a and the second individual liquid chamber 11b, respectively. The diaphragm 13 is made of a metal material such as stainless steel.

[0025] The pressure variable member 14 is provided on the surface of the diaphragm 13 opposite to the first individual liquid chamber 11a and the second individual liquid chamber 11b so as to be able to apply pressure to the diaphragm 13. The pressure variable member 14 includes a piezoelectric material such as barium titanate or barium zirconate, and includes a piezoelectric element that expands and contracts in response to an applied voltage. However, the pressure variable member 14 is not limited to one that includes a piezoelectric element, and an electrostatic actuator or the like may be used as long as it can apply pressure to the diaphragm 13. In this embodiment, the pressure variable member 14 includes a plurality of pressure variable members 14 that are paired with a plurality of diaphragms 13.

[0026] The pressure variable member 14 is driven, for example, expanded and contracted, in response to a drive signal as an applied voltage, and deforms the vibration plate 13, thereby changing the internal pressure of each of the first individual liquid chamber 11a and the second individual liquid chamber 11b.

[0027] The drive circuit 2 is an example of a drive unit that drives the pressure variable members 14. The drive circuit 2 is electrically connected to a plurality of pressure variable members 14, and outputs a drive signal including a predetermined voltage waveform, which is applied to the pressure variable members 14 to drive the pressure variable members 14.

[0028] The liquid ejection device 1 outputs a drive signal from the drive circuit 2 to the pressure variable member 14, which deforms the vibration plate 13 of the first individual liquid chamber 11a, thereby ejecting ink from the nozzle 110 of the first individual liquid chamber 11a. The liquid ejection device 1 also outputs a drive signal from the drive circuit 2 to the pressure variable member 14, which deforms the vibration plate 13 of the second individual liquid chamber 11b, thereby applying pressure to the second individual liquid chamber 11b. By applying pressure to the second individual liquid chamber 11b, the liquid ejection device 1 suppresses fluctuations in ejection characteristics such as the ejection speed of ink ejected from the nozzle 110 of the first individual liquid chamber 11a.

[0029] <Action of Liquid Discharge Device 1> The operation of the liquid ejection device 1 will be described in detail with reference to Figures 2 and 3. Figure 2 is a diagram illustrating the operation of the liquid ejection device 1 when ejecting ink 5. Figure 3 is a diagram illustrating the operation of the liquid ejection device 1 when ink 5 is replenished, for example, refilled, to the liquid ejection device 1 after ejecting the ink 5.

[0030] 2 and 3 show two first individual liquid chambers 11a1 and 11a2 and one second individual liquid chamber 11b out of the multiple first individual liquid chambers 11a and second individual liquid chambers 11b possessed by the liquid ejection device 1. The first individual liquid chamber 11a1 is in communication with the common liquid chamber 15 through a flow path 12a1. The first individual liquid chamber 11a2 is in communication with the common liquid chamber 15 through a flow path 12a2. The second individual liquid chamber 11b is in communication with the common liquid chamber 15 through a flow path 12b.

[0031] 2, when ink 5 is ejected from the first individual liquid chamber 11a1, the pressure variable member 14a1 expands toward the nozzle 110 in response to a drive signal, applying pressure to the first individual liquid chamber 11a1. This pressure causes the ink 5 in the first individual liquid chamber 11a1 to move into the through-hole of the nozzle 110a1 and simultaneously move through the flow path 12a1 toward the common liquid chamber 15. As the ink 5 moves into the through-hole of the nozzle 110a1, an ink droplet M is ejected from the nozzle 110a1.

[0032] For example, when the liquid ejection device 1 repeatedly ejects ink droplets M at a predetermined ejection frequency, the ink 5 repeatedly moves from the first individual liquid chamber 11a1 toward the common liquid chamber 15, which repeatedly generates pressure pressing against the ink 5 in the common liquid chamber 15. This repeated pressure may cause the common liquid chamber 15 to vibrate, and may also cause the first individual liquid chamber 11a2 to vibrate.

[0033] When the first individual liquid chamber 11a2 vibrates, the pressure generated by the vibration causes the ink 5 to move from the common liquid chamber 15 through the flow path 12a2 into the first individual liquid chamber 11a2, changing the liquid level of the ink 5 in the through-hole of the nozzle 110a2 of the first individual liquid chamber 11a2. In response to this change in the liquid level, ejection characteristics such as ejection speed vary when the ink 5 is ejected from the first individual liquid chamber 11a2 through the nozzle 110a2. If the vibration of the common liquid chamber 15 and the first individual liquid chamber 11a2 is a resonant vibration, the fluctuation in the ejection characteristics becomes more pronounced.

[0034] In this embodiment, when driving the pressure variable member 14a1 of the first individual liquid chamber 11a1 during ejection, the liquid ejection device 1 causes the pressure variable member 14b of the second individual liquid chamber 11b to perform a different driving operation from the driving operation of the pressure variable member 14a1. For example, when the pressure variable member 14a1 expands toward the nozzle 110a1, the liquid ejection device 1 causes the pressure variable member 14b to contract toward the common liquid chamber 15.

[0035] The liquid ejector 1 moves the ink 5 in the common liquid chamber 15 into the second individual liquid chamber 11b by contracting the pressure variable member 14b, and can absorb the pressure generated by the ink 5 moving from the first individual liquid chamber 11a to the common liquid chamber 15 during ejection. By absorbing this pressure, the liquid ejector 1 can suppress the movement of the ink 5 from the common liquid chamber 15 into the first individual liquid chamber 11a2, and can suppress changes in the height of the liquid surface of the ink 5 in the through hole of the nozzle 110a2. This allows the liquid ejector 1 to suppress fluctuations in ejection characteristics when ejecting ink 5 from the first individual liquid chamber 11a2.

[0036] 3, when the liquid ejector 1 is refilled with ink, after the ink 5 is ejected from the first individual liquid chamber 11a1, a suction force P, indicated by the white arrow, acts on the first individual liquid chamber 11a1. This suction force P causes the ink 5 in the first individual liquid chamber 11a2 to move into the common liquid chamber 15, and if the liquid ejector 1 does not have the second individual liquid chamber 11b, a force acting on the ink 5 in the first individual liquid chambers 11a1 and 11a2 toward the common liquid chamber 15. This changes the liquid level of the ink 5 in the through-holes of the nozzle 110a1 in the first individual liquid chamber 11a1 and the nozzle 110a2 in the first individual liquid chamber 11a2.

[0037] Since the timing at which the liquid level height of the ink 5 changes in the nozzle 110a1 of the first individual liquid chamber 11a1 and the nozzle 110a2 of 11a2 differs from each other, when the ink 5 is ejected from each of the first individual liquid chambers 11a1 and 11a2, the ejection characteristics vary, such as the ejection speed being different.

[0038] In this embodiment, for example, during refilling after ejecting ink 5 from the first individual liquid chamber 11a1, the pressure variable member 14b of the second individual liquid chamber 11b is driven differently from the pressure variable member 14a1 of the first individual liquid chamber 11a1. The liquid ejector 1 moves ink 5 from the second individual liquid chamber 11b to the common liquid chamber 15 by driving the pressure variable member 14b. This reduces the force acting on the first individual liquid chamber 11a2 to move ink 5 toward the common liquid chamber 15, thereby suppressing changes in the liquid level of ink 5 within the through-hole of the nozzle 110a2. As a result, the liquid ejector 1 can suppress fluctuations in ejection characteristics when ejecting ink 5 from each of the first individual liquid chambers 11a1 and 11a2.

[0039] <Example of driving signal by driving circuit 2 according to the first embodiment> Fig. 4 is a diagram illustrating an example of a drive signal generated by the drive circuit 2 according to the first embodiment. In Fig. 4, the horizontal axis represents time (μs) and the vertical axis represents potential (%). The drive signal is a signal including a voltage waveform that represents a change in potential over time.

[0040] The first drive signal 21a1 is a signal that drives the pressure variable member 14 of the first individual liquid chamber 11a, which is provided with the nozzle 110. The second drive signals 21b1, 21b2, and 21b3 are signals that drive the pressure variable member 14 of the second individual liquid chamber 11b, which is not provided with the nozzle 110. The second drive signals 21b1, 21b2, and 21b3 are each applied to a different second individual liquid chamber 11b.

[0041] When the first drive signal 21a1 is applied to the pressure variable member 14 of the first individual liquid chamber 11a, the pressure variable member 14 is driven in accordance with the potential, and the pressure in the first individual liquid chamber 11a changes, causing the nozzle 110 to eject ink 5.

[0042] On the other hand, when the second drive signals 21b1, 21b2, and 21b3 are applied to the pressure variable member 14 of the second individual liquid chamber 11b, the pressure variable member 14 is driven in accordance with the potential, and the pressure in the first individual liquid chamber 11a changes.

[0043] For example, the drive circuit 2 outputs a first drive signal 21a1 to the pressure variable member 14 of the first individual liquid chamber 11a, while simultaneously outputting second drive signals 21b1, 21b2, and 21b3 to the pressure variable member 14 of the second individual liquid chamber 11b. The voltage waveforms of the second drive signals 21b1, 21b2, and 21b3 are different from the voltage waveform of the first drive signal 21a1. Specifically, the magnitude of the potential and the timing (phase) of the potential change are different. Therefore, the drive operation of the pressure variable member 14 of the second individual liquid chamber 11b in response to the second drive signals 21b1, 21b2, and 21b3 differs from the drive operation of the pressure variable member 14 of the first individual liquid chamber 11a in response to the first drive signal 21a1.

[0044] The drive circuit 2 may output the second drive signals 21b1, 21b2, and 21b3 to the pressure variable member 14 of the second individual liquid chamber 11b at a timing shifted, in other words, non-parallel, from the timing at which it outputs the first drive signal 21a1 to the pressure variable member 14 of the first individual liquid chamber 11a. In this case as well, the drive operation of the pressure variable member 14 of the second individual liquid chamber 11b will be different from the drive operation of the pressure variable member 14 of the first individual liquid chamber 11a.

[0045] Although FIG. 4 illustrates second drive signals 21b1, 21b2, and 21b3 that include different voltage waveforms, second drive signals 21b1, 21b2, and 21b3 may all be the same as long as they are different from first drive signal 21a1.

[0046] Here, the ejection fluctuation may differ depending on the number or positions of the first individual liquid chambers from which ejection is to be performed. For this reason, in this embodiment, the drive circuit 2 changes the number of second individual liquid chambers 11b from which the pressure variable member 14 is driven, depending on at least one of the number or positions of the first individual liquid chambers 11a from which the pressure variable member 14 is driven.

[0047] For example, when driving the pressure variable members 14 of the five first individual liquid chambers 11a to eject ink 5, the drive circuit 2 drives the pressure variable members 14 of the two second individual liquid chambers 11b to apply pressure to the two second individual liquid chambers 11b. When driving the pressure variable members 14 of the ten first individual liquid chambers 11a to eject ink 5, the drive circuit 2 drives the pressure variable members 14 of the four second individual liquid chambers 11b to apply pressure to the four second individual liquid chambers 11b.

[0048] Alternatively, when ink 5 is ejected from first individual liquid chambers 11a that correspond to 50% of the total number of first individual liquid chambers 11a, the drive circuit 2 applies pressure to second individual liquid chambers 11b that correspond to 10% of the total number of second individual liquid chambers 11b.Furthermore, when ink 5 is ejected from first individual liquid chambers 11a that correspond to 30% of the total number of first individual liquid chambers 11a, the drive circuit 2 applies pressure to second individual liquid chambers 11b that correspond to 5% of the total number of second individual liquid chambers 11b.

[0049] The suppression effect of ejection fluctuations can be varied by varying the number of second individual liquid chambers 11b that drive the pressure variable member 14. In this embodiment, the number of second individual liquid chambers 11b that drive the pressure variable member 14, which can suitably suppress ejection fluctuations, is determined in advance depending on the number or positions of the first individual liquid chambers 11a that drive the pressure variable member 14. The drive circuit 2 then changes the number of second individual liquid chambers 11b that drive the pressure variable member 14 depending on the number or positions of the first individual liquid chambers 11a that drive the pressure variable member 14, thereby optimizing the suppression effect of ejection characteristic fluctuations. Furthermore, the liquid ejection device 1 can achieve a similar effect by changing the voltage waveform applied to the pressure variable member 14 of the second individual liquid chambers 11b depending on the number or positions of the first individual liquid chambers 11a that drive the pressure variable member 14.

[0050] <Effects of the liquid ejection device 1> The effects of the liquid ejection device 1 will be described.

[0051] Conventionally, liquid ejection devices may eject ink at different ejection frequencies depending on the combination of the speed and density at which ink is printed onto a print medium. Furthermore, liquid ejection devices may experience fluctuations in ejection characteristics, such as increases or decreases in the weight or velocity of ink droplets ejected at a specific frequency, depending on the structure of the individual liquid chambers that eject ink from the nozzles. To suppress such fluctuations in ejection characteristics, a technique for changing the voltage waveform of a drive signal that drives a pressure-variable member is known.

[0052] However, conventional techniques have required complex drive circuits to change the voltage waveform of the drive signal, and there have been cases where increasing the ejection frequency has been limited in order to ensure the time length of the voltage waveform.

[0053] On the other hand, a configuration has been disclosed in which, among the individual liquid chambers in which nozzles are provided, a drive signal of a voltage low enough to prevent ink ejection is applied to resting nozzles that do not eject ink, thereby damping resonant vibrations and suppressing fluctuations in ejection characteristics.

[0054] However, if a large voltage drive signal is applied to exert a large pressure in order to suppress vibration, this pressure can cause unnecessary ink to be ejected or leak from the nozzles of the individual liquid chambers, resulting in problems such as ink contamination of the printing medium.

[0055] The liquid ejection device 1 according to this embodiment has at least one second individual liquid chamber 11b that is not provided with a nozzle. Pressure is applied to the second individual liquid chamber 11b when ejecting ink 5 from the first individual liquid chamber 11a or when refilling the first individual liquid chamber 11a with ink 5. This allows the liquid ejection device 1 to suppress vibrations of the common liquid chamber 15 or the first individual liquid chamber 11a that occur during ejection or refilling, thereby suppressing fluctuations in the ejection characteristics of the ink 5 ejected from the first individual liquid chamber 11a. Furthermore, because the second individual liquid chamber 11b does not have a nozzle 110b, applying pressure to the second individual liquid chamber 11b does not cause the ink 5 in the second individual liquid chamber 11b to be ejected or leak out. Therefore, this embodiment provides a liquid ejection device 1 that can suppress fluctuations in ejection characteristics without limiting the pressure applied to the individual liquid chambers.

[0056] In this embodiment, the first individual liquid chambers 11a are arranged in a row, and the second individual liquid chambers 11b are arranged outside the ends of the first individual liquid chambers 11a arranged in a row. This arrangement allows the liquid ejection device 1 to provide the second individual liquid chambers 11b without affecting the spacing between the first individual liquid chambers 11a.

[0057] Furthermore, in this embodiment, the drive circuit 2 (drive unit) changes the number of second individual liquid chambers 11b that drive the pressure variable member 14, depending on at least one of the number and the position of the first individual liquid chambers 11a that drive the pressure variable member 14. This makes it possible to suitably suppress fluctuations in ejection characteristics that differ depending on the number or position of the first individual liquid chambers that are ejected.

[0058] Furthermore, in this embodiment, the drive circuit 2 drives the pressure variable members 14 of the first individual liquid chamber 11a and the second individual liquid chamber 11b in parallel. This allows the liquid ejection device 1 to simplify the operation of outputting drive signals by the drive circuit 2.

[0059] Furthermore, in this embodiment, the voltage waveforms of the second drive signals 21b1, 21b2, and 21b3 are different from the voltage waveform of the first drive signal 21a1. This allows the liquid ejection device 1 to drive the pressure variable member 14 of the second individual liquid chamber 11b in a different manner from the drive operation of the pressure variable member 14 of the first individual liquid chamber 11a. As a result, the liquid ejection device 1 can suppress fluctuations in ejection characteristics that correspond to the pressure generated by driving the pressure variable member 14 of the first individual liquid chamber 11a.

[0060] [Second embodiment] A second embodiment will be described. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant explanations will be omitted as appropriate. This also applies to the following embodiments.

[0061] Fig. 5 is a diagram showing an example of a drive signal from the drive circuit 2 according to the second embodiment. In Fig. 5, the horizontal axis represents time (µs) and the vertical axis represents potential (%).

[0062] The first drive signal 21a2 is a signal that drives the pressure variable member 14 of the first individual liquid chamber 11a, which has the nozzle 110. The second drive signal 21b4 is a signal that drives the pressure variable member 14 of the second individual liquid chamber 11b, which has no nozzle 110.

[0063] As shown in FIG. 5, the maximum potential difference Vb between the maximum potential Vb1 and minimum potential Vb2 in the voltage waveform of the second drive signal 21b4 is greater than the maximum potential difference Va between the maximum potential Va1 and minimum potential Va2 in the voltage waveform of the first drive signal 21a2.

[0064] Even when the common liquid chamber 15 or the first individual liquid chamber 11a vibrates greatly during ejection or refilling, the liquid ejection device 1 can apply a large pressure to the second individual liquid chamber 11b and the common liquid chamber 15 and suppress the vibration by making the maximum potential difference Vb larger than the maximum potential difference Va. Because the second individual liquid chamber 11b does not have a nozzle 110, ink 5 will not be ejected or leak out from the second individual liquid chamber 11b even if the maximum potential difference Vb is increased and the applied pressure is increased. In this way, this embodiment can provide a liquid ejection device 1 that can suppress fluctuations in ejection characteristics without limiting the pressure applied to the individual liquid chambers.

[0065] The effects other than those described above are the same as those of the first embodiment.

[0066] [Third embodiment] A third embodiment will now be described. Fig. 6 is a diagram showing an example of a drive signal from a drive circuit 2 according to the third embodiment. In Fig. 6, the horizontal axis represents time (µs) and the vertical axis represents potential (%).

[0067] The first drive signal 21a3 is a signal that drives the pressure variable member 14 of the first individual liquid chamber 11a, which has the nozzle 110. The second drive signal 21b5 is a signal that drives the pressure variable member 14 of the second individual liquid chamber 11b, which has no nozzle 110.

[0068] As shown in Figure 6, the phase φb of the voltage waveform of the second drive signal 21b5 is opposite in phase to the phase φa of the voltage waveform of the first drive signal 21a3. Here, "opposite phase" means that the phase angle is shifted by approximately 180 degrees. "Approximately 180 degrees" does not require a strict 180-degree difference, but rather means that some degree of deviation is acceptable. For example, when the phase φb is shifted from the phase φa by more than 175 degrees and less than 185 degrees, the phase φb can also be said to be opposite in phase to the phase φa.

[0069] By making the phase φb the opposite phase to the phase φa, the liquid ejector 1 generates a pressure in the opposite direction to the pressure of the vibrations generated by applying the first drive signal 21a3 to the first individual liquid chamber 11a, thereby canceling out the pressure of the vibrations. In this way, this embodiment can provide a liquid ejector 1 that can suppress fluctuations in ejection characteristics without limiting the pressure applied to the individual liquid chambers.

[0070] The effects other than those described above are the same as those of the first embodiment.

[0071] Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

[0072] The ordinal numbers, quantities, and other figures used in the description of the embodiments are all provided as examples to specifically explain the technology of the present invention, and the present invention is not limited to the illustrated figures. Furthermore, the connection relationships between the components are provided as examples to specifically explain the technology of the present invention, and do not limit the connection relationships that realize the functions of the present invention. [Explanation of symbols]

[0073] 1 Liquid discharge device 11a 1st individual liquid chamber 110 nozzle 11b 2nd individual liquid chamber 12 Flow path 13 Diaphragm 14 Pressure variable member 15 Common liquid chamber 151 Supply port 152 Outlet 2. Drive circuit (an example of a drive unit) 3 Stopper 41 Supply tube 42 Discharge tube 5. Ink 21a1, 21a2 First drive signal 21b1, 21b2, 21b3, 21b4, 21b5 Second drive signal M ink droplets Va1, Vb1 maximum potential Va2, Vb2 minimum potential Va, Vb maximum potential difference φa, φb phase [Prior art documents] [Patent documents]

[0074] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-226587

Claims

1. at least one first individual liquid chamber provided with a nozzle for ejecting liquid; At least one second separate liquid chamber in which the nozzle is not provided; a flexible vibration plate provided in each of the first and second individual liquid chambers; a pressure varying member that varies the internal pressure of each of the first and second individual liquid chambers by deforming the vibration plate in response to a drive signal; a common liquid chamber or a common flow channel communicating with each of the first and second individual liquid chambers; a drive unit that drives the pressure variable member, The liquid ejection device, wherein the drive section changes the number of the second individual liquid chambers for which the pressure variable member is driven, depending on the number of the first individual liquid chambers for which the pressure variable member is driven.

2. the first individual liquid chamber is provided with a plurality of the first individual liquid chambers arranged side by side, The liquid ejection device according to claim 1 , wherein the second individual liquid chamber is provided outside an end of the plurality of first individual liquid chambers that are arranged side by side.

3. 3. The liquid ejection device according to claim 1, wherein the drive section drives the pressure variable members of the first and second individual liquid chambers in parallel.

4. the drive unit outputs a first drive signal for driving the pressure variable member of the first individual liquid chamber and a second drive signal for driving the pressure variable member of the second individual liquid chamber; 4. The liquid ejection device according to claim 1, wherein the voltage waveform of the second drive signal is different from the voltage waveform of the first drive signal.

5. The liquid ejection device according to claim 4 , wherein a maximum potential difference between a maximum potential and a minimum potential in the voltage waveform of the second drive signal is greater than the maximum potential difference in the voltage waveform of the first drive signal.

6. 6. The liquid ejection device according to claim 4, wherein the phase of the voltage waveform of the second drive signal is opposite to the phase of the voltage waveform of the first drive signal.

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