Liquid ejection device

Abstract

To reduce a temperature difference among liquids in pressure chambers corresponding to the respective nozzles even when heat generated by a drive circuit has a greater impact on the temperature rise of the liquid in the pressure chamber than heat generated by an electromechanical conversion element.SOLUTION: A liquid ejection device comprises a liquid ejection head that, when a drive signal is applied by a drive circuit 101 to each of electromechanical conversion elements 5A to 5E changing pressure in multiple pressure chambers communicating with multiple nozzles, ejects, from multiple nozzles onto an ejection target medium, liquids in the multiple pressure chambers having flowed thereinto from a common flow path. The liquid ejection device includes a control unit that controls liquid flow rates in the multiple pressure chambers so that a liquid flow rate in a short-distance pressure chamber 4A that is located at a shorter distance from the drive circuit is greater than a liquid flow rate in a long-distance pressure chamber 4E that is located at a longer distance from the drive circuit.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, there has been known a device for ejecting liquid that includes a liquid ejection head that applies a drive signal from a drive circuit to each electromechanical conversion element that changes the pressure in multiple pressure chambers that are respectively connected to multiple nozzles, thereby ejecting liquid from multiple pressure chambers that flow in from a common flow path onto an ejection medium from multiple nozzles.

[0003] Patent Document 1 discloses a droplet ejection device that applies a drive signal to a piezoelectric element on a diaphragm provided on the side facing the nozzle-forming wall of a pressure chamber in which a nozzle is formed, thereby pressurizing the pressure chamber and ejecting liquid from the pressure chamber through the nozzle. In this droplet ejection device, the liquid in the pressure chamber of the end nozzle located at the end of the nozzle row is easily cooled by the air flowing outside and drops in temperature, while the liquid in the pressure chamber of the central nozzle located at the center of the nozzle row is less likely to drop in temperature. In the droplet ejection device of Patent Document 1, in order to reduce the temperature difference between the pressure chambers corresponding to each nozzle, the amount of liquid ejected from the end nozzles is greater than that from the central nozzles during the preliminary ejection (blank ejection) process. As a result, the heat generated by the piezoelectric element during preliminary ejection causes the temperature of the liquid in the pressure chamber of the end nozzle to rise more than that of the central nozzle, thereby reducing the temperature difference between the pressure chambers corresponding to each nozzle. Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the conventional method, there are cases where it is not possible to reduce the temperature difference of the liquid between the pressure chambers corresponding to the nozzles. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a liquid ejection device equipped with a liquid ejection head that applies a drive signal from a drive circuit to each electromechanical conversion element that changes the pressure in a plurality of pressure chambers that are respectively connected to a plurality of nozzles, thereby ejecting liquid from the plurality of pressure chambers that flow in from a common flow path from the plurality of nozzles onto an ejection medium, and is characterized by having a control unit that controls the liquid flow rate in the plurality of pressure chambers so that the liquid flow rate in a close-distance pressure chamber that is located a short distance from the drive circuit is greater than the liquid flow rate in a far-distance pressure chamber that is located a long distance from the drive circuit. [Effects of the Invention]

[0006] According to the present invention, even if the heat generated by the drive circuit has a greater effect on the temperature rise of the liquid in the pressure chamber than the heat generated by the electromechanical conversion element, the temperature difference of the liquid between the pressure chambers corresponding to each nozzle can be reduced. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a nozzle plate vibration type liquid ejection head according to an embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing a nozzle surface of the liquid ejection head. [Figure 3] 2 is an enlarged cross-sectional view of a portion surrounded by a dashed line indicated by the symbol X in FIG. 1. [Figure 4] FIG. 3 is an explanatory diagram showing a wiring portion that connects a drive circuit and a piezoelectric element of the liquid ejection head. [Figure 5] FIG. 3 is an enlarged explanatory view showing a wiring portion connecting a drive circuit and a piezoelectric element of the liquid ejection head. [Figure 6] FIG. 2 is a block diagram showing the hardware configuration of a control system of an inkjet printing apparatus equipped with the liquid ejection head. [Figure 7] FIG. 2 is a block diagram showing the hardware configuration of a head driving unit of the liquid ejection head. [Figure 8] FIG. 2 is an explanatory diagram showing an example of a cross section of a pressure chamber substrate and a nozzle plate that constitute the liquid ejection head. [Figure 9]10(a) to 10(d) are explanatory diagrams illustrating examples of the configuration for performing the idle discharge operation in Operation Example 1. FIG. [Figure 10] 1(a) is an explanatory diagram showing an example of the arrangement of temperature sensors in Operation Example 1. FIG. 1(b) is a graph showing an example of the detection results of temperature sensors installed in the drive circuit. [Figure 11] FIG. 10 is an explanatory diagram showing another example of the arrangement of temperature sensors in the first operational example. [Figure 12] FIG. 10 is an explanatory diagram showing yet another example of the arrangement of temperature sensors in the first operational example. [Figure 13] FIG. 10 is an explanatory diagram showing an example in which a liquid supply port that supplies liquid to a common flow channel is connected to the common flow channel at one end side of a nozzle row. [Figure 14] FIG. 4 is an explanatory diagram showing an example of a common flow path circulation configuration. [Figure 15] FIG. 4 is an explanatory diagram showing an example of a pressure chamber circulation configuration. [Figure 16] FIG. 10 is an explanatory diagram showing an example of a configuration in which a piezoelectric element is arranged on a vibration plate provided on the side of a pressure chamber facing a nozzle forming wall. [Figure 17] FIG. 1 is a schematic diagram illustrating a printing apparatus according to an embodiment. [Figure 18] FIG. 2 is an explanatory plan view of an example of a head unit of the printing apparatus. [Figure 19] FIG. 10 is an explanatory plan view of the main parts of another printing device. [Figure 20] FIG. 2 is a side view illustrating the main parts of the printing apparatus of the present embodiment. [Figure 21] FIG. 2 is a plan view illustrating a main part of the liquid ejection unit according to the embodiment. [Figure 22] FIG. 2 is a front view illustrating the liquid ejection unit of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment in which the present invention is applied to an inkjet recording apparatus, which is an apparatus for ejecting liquid, will be described below. The present invention is not limited to the embodiments shown below, but may be modified, added, modified, deleted, or otherwise altered within the scope of what a person skilled in the art can conceive, and any embodiment is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0009] The liquid ejection head in this embodiment is a nozzle plate vibration type liquid ejection head that ejects liquid in a pressure chamber from the nozzle by varying the pressure in the pressure chamber using an electromechanical conversion element (actuator) provided on a nozzle plate having nozzles. The nozzle plate vibration type has the advantage that droplets can be ejected with less force than a typical unimorph type piezo head (which ejects liquid by vibrating the surface facing a wall portion (nozzle communication wall) having a communication port that communicates with the nozzle of the pressure chamber), and this can reduce the power consumption of the actuator.

[0010] Increasing nozzle density limits the space available for laying out the wiring required for voltage application, making wiring construction on the substrate surface difficult. By constructing the wiring and drive circuits within the substrate, it is possible to lay out the wiring even with a high nozzle density (e.g., 1200 npi). Lead zirconate titanate (PZT) is commonly used as the piezoelectric material for actuators due to its high piezoelectric properties. However, when depositing a piezoelectric film on a substrate containing wiring and drive circuits, the PZT deposition and crystallization temperature must be at least 450°C. Therefore, using PZT as the piezoelectric material would prevent the drive circuits and their wiring within the substrate from withstanding high temperatures. Therefore, in configurations where wiring and drive circuits are constructed within the substrate, a piezoelectric material with a lower deposition temperature than PZT is required, and a material with lower piezoelectric properties than PZT is selected.

[0011] Even if a high-piezoelectric-constant piezoelectric material such as PZT, potassium sodium niobate (KNN), or a material containing any of these as its main component is used, which is manufactured through a process including a heat treatment at 450°C or higher, it is possible to form a drive circuit and wiring on the same substrate by devising a manufacturing method. For example, by using a method in which a drive circuit manufactured on a separate substrate is transferred onto an actuator substrate on which a piezoelectric element is manufactured, a high-piezoelectric-constant piezoelectric element and a drive circuit can be formed on the same substrate.

[0012] FIG. 1 is a cross-sectional view that schematically shows a nozzle plate vibration type liquid ejection head according to this embodiment. FIG. 2 is a perspective view schematically showing the nozzle surface of the liquid ejection head of this embodiment. The liquid ejection head 1 includes a nozzle plate 110, a pressure chamber substrate 100, and a common flow path substrate 120.

[0013] The nozzle plate 110 is thin-film shaped and has a plurality of nozzles 2 that eject liquid, and piezoelectric elements 5 that function as electromechanical conversion elements that are annular actuators arranged around the nozzles 2. The pressure chamber substrate 100 has a plurality of pressure chambers (also called individual liquid chambers or pressurized liquid chambers) 4 that communicate with the plurality of nozzles 2. The nozzles 2 (vibration membranes 103) are located on one side of each pressure chamber 4, and openings 4a of the pressure chambers are located on the side opposite to that side. The common flow path substrate 120 has a common flow path 3 that communicates with the plurality of pressure chambers 4.

[0014] FIG. 3 is an enlarged cross-sectional view of a portion surrounded by a broken line indicated by the symbol X in FIG. The pressure chamber substrate 100 is an SOI (Silicon on Insulator) substrate, and a drive circuit 101 and a wiring section 102 are arranged on the side where the vibration membrane 103 is formed. The drive circuit 101 is a CMOS circuit including transistors, resistors, etc. The wiring section 102 includes wiring for applying a drive waveform (drive signal) from the drive circuit 101 to the second electrode 53 (also referred to as an upper electrode).

[0015] The nozzle plate 110 has a nozzle forming section (film) 111 formed with a plurality of nozzles 2 and covering the piezoelectric elements 5, and a liquid-repellent film 112 is formed on the nozzle surface of this nozzle forming section 111. When liquid is continuously ejected, mist generated simultaneously with the ejection adheres to the nozzle surface. If a large amount of this mist adheres to the nozzle surface, the liquid ejected from the nozzles 2 may be affected by the liquid adhering to the nozzle surface and may deviate from the desired landing position. By forming the liquid-repellent film 112 on the nozzle surface, it is possible to prevent the liquid from adhering to the nozzle surface, and it is also possible to prevent the liquid ejected from the nozzles 2 from being affected by the liquid adhering to the nozzle surface.

[0016] The piezoelectric element 5 of the nozzle plate 110 has a first electrode 51 (also referred to as a lower electrode), a piezoelectric film 52, and a second electrode 53 (also referred to as an upper electrode). The piezoelectric element 5 is covered with a first insulating film 8a. The first insulating film 8a has formed therein a hole-shaped fourth contact 7d for electrical connection to the first electrode 51 and a hole-shaped fifth contact 7e for electrical connection to the second electrode 53.

[0017] In addition, the first insulating film 8a is formed with a first lead-out wiring 9a that electrically connects the first electrode 51 of the piezoelectric element 5 and the wiring portion 102 of the pressure chamber substrate 100, and a second lead-out wiring 9b that electrically connects the second electrode 53 of the piezoelectric element 5 and the wiring portion 102 of the pressure chamber substrate 100.

[0018] The first extraction wiring 9a is electrically connected to the first electrode 51 via the fourth contact 7d, and is electrically connected to the wiring portion 102 via the first contact 7a. The second extraction wiring 9b is electrically connected to the second electrode 53 via the fifth contact 7e, and is electrically connected to the wiring portion 102 via the second contact 7b. The first extraction wiring 9a and the second extraction wiring 9b are covered with a second insulating film 8b. In this embodiment, the second insulating film 8b also covers the piezoelectric element 5 and has the function of preventing moisture that has entered the nozzle forming portion 111 made of resin from entering the piezoelectric element 5, thereby protecting the piezoelectric element 5.

[0019] It is also possible to provide lead wiring portions for the first electrode 51 and the second electrode 53, respectively, and to electrically connect them directly to the wiring portion 102 via contacts opened in the vibration membrane. Also, an adhesion improving film may be formed on the second insulating film 8b to ensure adhesion with the nozzle forming portion 111.

[0020] The liquid filled in the liquid ejection head 1 enters the nozzle 2 and forms a meniscus inside the nozzle. When a predetermined drive waveform is applied from the drive circuit 101 to each of the electrodes 51, 53 of the piezoelectric element 5, the piezoelectric film 52 is displaced (vibrated), and the vibrating film 103 vibrates in the vertical direction in FIG. 3 so that the wall portion of the pressure chamber substrate 100 that separates the pressure chambers 4 acts as a fixed end. The vibration of the vibrating film 103 causes a pressure change in the liquid inside the pressure chamber, and the liquid is ejected from the nozzle 2.

[0021] Furthermore, in the liquid ejection head 1 of this embodiment, a protective film 11 is formed on the inner circumferential surfaces of the nozzles 2, the inner circumferential surfaces of the pressure chambers 4, and the bottom surface of the common flow channel 3 as a surface layer that is lyophilic to the liquid ejected by the liquid ejection head 1 and prevents erosion of the liquid. In this embodiment, the liquid ejected by the liquid ejection head 1 is alkaline, and the pressure chamber substrate 100 and vibration membrane 103 that form the pressure chambers 4 are made of single crystal silicon and silicon oxide. These materials are vulnerable to alkaline liquids and are eluted and eroded by alkaline solutions. To prevent this, a liquid-resistant protective film 11 that prevents erosion of the liquid is formed, thereby protecting the pressure chamber substrate 100 and vibration membrane 103 from the liquid.

[0022] Furthermore, the pressure chambers 4 and nozzles 2 are formed by dry etching. Because the dry etching gas contains fluorine, a fluorine-containing surface film is formed on the inner wall surfaces of the pressure chambers 4 and the inner circumferential surface of the nozzle 2 after etching, making the inner wall surfaces of the pressure chambers 4 and the inner circumferential surface of the nozzle 2 liquid-repellent. If the inner circumferential surface of the pressure chamber 4 is liquid-repellent, the liquid will not wet and spread over the inner circumferential surface of the pressure chamber 4 when filling it, which may prevent the pressure chamber 4 from being filled properly with liquid and may result in air bubbles forming in the corners of the pressure chamber 4, etc.

[0023] In this embodiment, the protective film 11 having lyophilic properties is formed on the inner peripheral surface of the pressure chamber 4 and the inner peripheral surface of the nozzle 2, thereby improving the wettability of the liquid to the inner peripheral surfaces of the pressure chamber 4 and the nozzle 2. The protective film 11 only needs to have a higher lyophilicity to the liquid than the film formation surface (the surface below the protective film 11) of the pressure chamber 4 or the nozzle 2 on which the protective film 11 is formed. If the solvent of the liquid is aqueous, a highly hydrophilic protective film is used, and if the solvent of the liquid is oil-based, a highly lyophilic protective film is used, thereby forming a highly lyophilic protective film.

[0024] In this way, by forming the protective film 11, which has lyophilicity to the liquid filling the pressure chamber 4, on the inner circumferential surfaces of the nozzle 2 and the pressure chamber 4, the liquid easily spreads over the inner circumferential surfaces of the pressure chamber 4 and the nozzle 2 when filling the pressure chamber 4. As a result, the liquid filling property can be improved, and the pressure chamber 4 and the nozzle 2 can be filled with the liquid well without applying pressure or suction when filling the liquid. Therefore, it is possible to prevent cracks from occurring in the vibration membrane 103 when filling the liquid.

[0025] Because the solvent for the liquid in this embodiment is aqueous, forming a protective film 11 that does not contain at least fluorine on the inner surfaces of the pressure chamber 4 and the nozzle 2 improves lyophilicity compared to a fluorine-containing surface film formed by dry etching. Furthermore, because this film comes into direct contact with various liquids, it is desirable to use a liquid-resistant material, such as a metal oxide that forms a passivation state. To further improve lyophilicity, a material in which silicon dioxide (SiO2) is mixed with the passivation metal oxide at the molecular level can be used. The SiO2 of the protective film 11 has its surface substituted with OH groups that have hydrophilic properties. This further enhances hydrophilicity of the protective film 11. Examples of metals that can be used in the above metal oxides include tantalum (Ta), niobium (Nb), titanium (Ti), zirconium (Zr), hafnium (Hf), and tungsten (W), which have high oxidation state compatibility. Zr and Hf, which have valences similar to those of SOI2, and Ta, which has a valence close to or slightly different from those, are particularly desirable.

[0026] Furthermore, for example, the protective film 11 may have a two-layer structure of a liquid-resistant film and a liquid-philic film. In this case, after a liquid-resistant film is formed on the inner circumferential surfaces of the nozzle 2 and the pressure chamber 4, a liquid-philic film is formed on the liquid-resistant film.

[0027] In this embodiment, a lyophilic protective film 11 is also formed on the surface of the pressure chamber substrate 100 opposite to the film-forming surface of the vibration membrane 103, which constitutes the bottom surface of the common flow channel 3. However, the protective film 11 on this surface may be liquid-resistant only. However, the process of forming the protective film 11 on the bottom surface of the common flow channel 3 must be performed separately from the process of forming the lyophilic protective film on the inner circumferential surface of the nozzle and the wall surface of the pressure chamber, which may increase the number of manufacturing steps. Furthermore, by forming the protective film 11 on the bottom surface of the common flow channel 3, the liquid can easily wet and spread over the bottom surface of the common flow channel 3, thereby improving the liquid filling properties. For this reason, it is preferable to form a lyophilic protective film 11 on the surface of the pressure chamber substrate 100 opposite to the film-forming surface of the vibration membrane 103, which constitutes the bottom surface of the common flow channel 3.

[0028] The material of the vibrating membrane 103 may be any material that is at least insulating, such as SiO2, SiN, metal oxide, resin, etc. However, to increase the displacement, a material with a low Young's modulus is desirable, and considering the difference in linear expansion coefficient with the pressure chamber substrate 100, SiO2 (silicon dioxide) is the most desirable material for the vibrating membrane 103, as this difference is relatively small.

[0029] For example, a platinum film can be suitably used for the first electrode layer 151 and the second electrode layer 153. As the piezoelectric material constituting the piezoelectric layer 152, a piezoelectric material (a material containing AlN, ScAlN, or the like as a main component) produced through a heat treatment process at a temperature of less than 450°C is used.

[0030] Aluminum nitride piezoelectric materials are compounds of trivalent aluminum cations and trivalent nitrogen anions, and have a hexagonal crystal structure. Substitutional materials include those in which trivalent aluminum is replaced with boron, scandium, yttrium, lanthanum, and lanthanoid elements. Scandium-substituted materials include, for example, Al (1-x) ,Sc xThe materials with Yb substitution as lanthanide element are shown as N, e.g., Al (1-x) ,Yb x It is indicated by N.

[0031] As a derivative material of aluminum nitride, there is a material design that combines divalent and tetravalent elements to have the same role as trivalent elements, and it has been reported that it has better piezoelectric properties than aluminum nitride. Specifically, Mg 0.5 ,Zr 0.5 N, Zn 0.5 ,Hf 0.5 Examples of suitable materials include N. Other examples include hexagonal zinc oxide and magnesium zinc oxide.

[0032] FIG. 4 is an explanatory diagram showing the wiring portion 102 that connects the drive circuit 101 and the piezoelectric element 5 of the liquid ejection head 1 in this embodiment. FIG. 5 is an enlarged explanatory diagram showing the wiring portion 102 that connects the drive circuit 101 and the piezoelectric element 5 of the liquid ejection head 1 in this embodiment. 4, one drive circuit 101 is connected to each of the second electrodes 53 (upper electrodes) of the five piezoelectric elements 5A to 5E. In more detail, ten nozzle rows extending in the left-right direction in the figure are wired in such a way that five nozzle rows are assigned to each of the top and bottom of the figure.

[0033] In this embodiment, the nozzle pitch in the left-right direction in the figure (nozzle pitch within the same nozzle row) is 212 [μm], and the nozzle pitch in the up-down direction in the figure (nozzle pitch between adjacent nozzle rows) is 191 [μm], and a high nozzle density of 1200 [npi] is achieved by a liquid ejection head consisting of 10 nozzle rows arranged so that the nozzle positions in the left-right direction in the figure are shifted by 21.2 [μm] between adjacent nozzle rows.

[0034] Generally, the viscosity of the liquid used in the liquid ejection head 1 often changes depending on the temperature. When the viscosity of the liquid changes, the amount of liquid ejected from the nozzles 2 fluctuates, making it difficult to eject the desired amount of liquid. As a result, if there is a temperature difference in the liquid between the nozzles 2 of the liquid ejection head 1 (if there is a temperature difference between the liquid in the pressure chambers 4 corresponding to each nozzle 2), variation in the amount of liquid ejected between the nozzles 2 will occur.

[0035] When a piezoelectric element with a high piezoelectric constant, such as PZT, is used as the piezoelectric element 5, the heat generated by the piezoelectric element is relatively large among heat sources that can affect the temperature rise of the liquid in each pressure chamber 4, and the heat generated by the piezoelectric element is dominant in the temperature rise of the liquid in each pressure chamber 4. However, in this embodiment, as described above, a piezoelectric material with a low piezoelectric constant, primarily composed of AlN or ScAlN, is used for the piezoelectric element 5. Such a piezoelectric element 5 generates less heat during operation (for example, about 1 / 10) than a piezoelectric element made of a piezoelectric material with a high piezoelectric constant, such as PZT. Therefore, heat generated by heat sources other than the piezoelectric element (for example, the drive circuit 101) can affect the temperature rise of the liquid in each pressure chamber 4.

[0036] In this case, the far-distance pressure chambers that are far away from the other heat source are less susceptible to the heat generated by the other heat source, while the near-distance pressure chambers that are far away from the other heat source are more susceptible to the heat generated by the other heat source. Therefore, the temperature difference between the liquid is likely to be large between the far-distance pressure chambers and the near-distance pressure chambers that are far away from the other heat source, resulting in variations in the amount of liquid ejected between the nozzles 2 corresponding to the far-distance pressure chambers and the near-distance pressure chambers, respectively.

[0037] FIG. 6 is a block diagram showing the hardware configuration of a control system of an inkjet recording apparatus 10 equipped with the above-described liquid ejection head 1. As shown in FIG. The inkjet recording device 10 is configured by, in addition to the liquid ejection head 1 described above, a control unit 600, a transport drive unit 710, an operation display unit 720, and an input / output interface 730, which are interconnected via a bus line 740.

[0038] The liquid ejection head 1 is equipped with a head driving unit 20 that controls a driving circuit 101 to drive the liquid ejection head 1. In response to a control signal input from a control unit 600, the head driving unit 20 causes the driving circuit 101 to generate a driving waveform that causes the piezoelectric elements 5 in the liquid ejection head 1 to deform. When this driving waveform is input to each piezoelectric element 5 of the liquid ejection head 1, the liquid in the pressure chambers 4 that communicate with the nozzles 2 is pressurized, ejection energy is applied, and the liquid is ejected from the corresponding nozzle 2.

[0039] The control unit 600 has a CPU (Central Processing Unit) 610, a storage unit 620, a RAM (Random Access Memory) 630, and a ROM (Read Only Memory) 640. The CPU 610 reads out various control programs and setting data stored in the ROM 640, stores them in the RAM 630, executes them, and performs various arithmetic processing. The CPU 610 also controls the overall operation of the inkjet recording apparatus 10.

[0040] The conveyance drive unit 710 supplies a drive signal to a conveyance motor based on a control signal supplied from the control unit 600, and conveys the recording material, which is the ejection receiving medium, at a predetermined speed and timing. The operation display unit 720 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as a touch panel overlaid on the screen of the display device and operation keys. The operation display unit 720 displays various information on the display device and also supplies operation signals corresponding to user input operations on the input device to the control unit 600. The input / output interface 730 mediates the transmission and reception of data between the external device 800 and the control unit 600. The bus line 740 is a path for transmitting and receiving signals between the control unit 600 and other components.

[0041] FIG. 7 is a block diagram showing the hardware configuration of the head driving unit 20 of the liquid ejection head 1. As shown in FIG. The head driving unit 20 includes driving waveform correction units 21-1 to 21-N (where "N" is the number of nozzles on the liquid ejection head 1) corresponding to each nozzle 2 on the liquid ejection head 1, a head control unit 22, a basic driving waveform generation unit 23, and a driving waveform correction information storage unit 24.

[0042] The head control unit 22 converts image data input from the control unit 600 into control signals for each nozzle 2 of the liquid ejection head 1. The basic drive waveform generation unit 23 generates a basic drive waveform that enables a reference ejection operation in accordance with the image pattern, transport speed, and printing environment such as temperature and humidity, based on the control signals input from the head control unit 22. The drive waveform correction information storage unit 24 stores information indicating the nozzle numbers of nozzles that require correction, and information indicating the amount of correction.

[0043] The drive waveform correction units 21-1 to 21-N perform a process of correcting the basic drive waveform of the drive waveform (drive signal) supplied from the basic drive waveform generation unit 23 based on the correction information read from the drive waveform correction information storage unit 24. As a result, the drive waveform from the drive circuit 101 is supplied to the piezoelectric elements 5 corresponding to each nozzle 2, and each nozzle 2 can be given individually different ejection characteristics, enabling appropriate ink ejection from each nozzle 2.

[0044] In this embodiment, different ejection characteristics are assigned to each nozzle, but this is not limiting, and ejection characteristics may be assigned to each nozzle row. The unit for assigning ejection characteristics may be determined based on constraints such as the memory capacity of the device and the load on the applied voltage.

[0045] FIG. 8 is an explanatory diagram showing an example of a cross section of the pressure chamber substrate 100 and the nozzle plate 110 that constitute the liquid ejection head 1 in this embodiment. In this embodiment, as described above, the drive circuit 101 is formed on the nozzle plate 110, which serves as an actuator substrate on which the piezoelectric elements 5 (5A to 5E) are formed, and the wiring section 102 between the drive circuit 101 and the piezoelectric elements 5A to 5E is also formed on the nozzle plate 110. In this configuration in which the drive circuit 101 and the piezoelectric elements 5A to 5E are formed on the same substrate, the drive circuit 101 is disposed in a position close to the area in which the piezoelectric elements 5A to 5E are formed, as shown in FIGS. 4 to 6, in order to shorten the wiring length. The drive circuit 101 applies a drive waveform to the piezoelectric elements 5A to 5E, and generates a considerable amount of heat. This can have a significant effect on the temperature rise of the liquid in the pressure chambers 4A to 4E corresponding to each of the piezoelectric elements 5A to 5E.

[0046] 4 (front-rear direction on the plane of FIG. 6), ten nozzle rows are provided, and drive circuits 101 are arranged on both sides of each of the ten nozzle rows. Therefore, a far-distance pressure chamber (e.g., pressure chamber 4E) that is separated a great distance from the drive circuit 101 is less susceptible to the heat generated by the drive circuit 101, whereas a near-distance pressure chamber (e.g., pressure chamber 4A) that is separated a short distance from the drive circuit 101 is more susceptible to the heat generated by the drive circuit 101. As a result, the temperature difference in the liquid is likely to be large between the far-distance pressure chamber and the near-distance pressure chamber that are separated a different distance from the drive circuit 101, and this causes variations in the amount of liquid ejected between the nozzles corresponding to the far-distance pressure chamber and the near-distance pressure chamber.

[0047] Therefore, in this embodiment, the liquid flow rate of the multiple pressure chambers 4A-4E is controlled so that the liquid flow rate in the near-distance pressure chambers, which are located closer to the drive circuit 101, is greater than the liquid flow rate in the far-distance pressure chambers, which are located farther from the drive circuit 101. Increasing the liquid flow rate in the pressure chambers 4A-4E promotes agitation of the liquid in the pressure chambers 4A-4E. This, for example, promotes replacement of the liquid near the nozzles, which are particularly difficult to flow in the pressure chambers 4A-4E when not driven, and can lower the temperature of the liquid ejected from the nozzles (liquid near the nozzles in the pressure chambers 4A-4E). Therefore, by controlling the liquid flow rate in this embodiment, the temperature of the liquid in the near-distance pressure chambers (particularly the temperature of the liquid ejected from the nozzles (liquid near the nozzles in the pressure chambers 4A-4E)) can be lowered compared to the temperature of the far-distance pressure chambers. As a result, the temperature difference between the liquid in the far-distance pressure chambers and the near-distance pressure chambers can be reduced, thereby suppressing variations in the liquid ejection rate between the nozzles.

[0048] Furthermore, by increasing the liquid flow rate within the pressure chambers 4A-4E, it is possible to make the liquid inflow rate into the near-distance pressure chambers, which are located closer to the drive circuit 101, greater than the liquid inflow rate into the far-distance pressure chambers, which are located farther from the drive circuit 101. In this case, the liquid flowing into the pressure chambers 4A-4E from the common flow path 3 is typically at a lower temperature than the liquid in each pressure chamber 4A-4E. Furthermore, the greater the liquid inflow rate into the pressure chambers 4A-4E, the greater the amount of liquid discharged from the pressure chambers 4A-4E, resulting in a greater amount of liquid whose temperature has risen within the pressure chambers 4A-4E being discharged from the pressure chambers 4A-4E. Therefore, by controlling the liquid flow rate according to this embodiment, the temperature of the liquid in the near-distance pressure chambers can be lowered than that of the far-distance pressure chambers. As a result, the temperature difference between the liquid in the far-distance pressure chambers and the near-distance pressure chambers can be reduced, thereby suppressing variations in the liquid ejection rate between nozzles.

[0049] [Operation example 1] Next, an example of controlling the amount of liquid flowing through the pressure chambers 4A to 4E in this embodiment (hereinafter, this example will be referred to as "Operation Example 1") will be described. In the liquid flow rate control of Operation Example 1, the drive waveform is controlled so that the amount of blank discharge during a predetermined blank discharge time in which the liquid in the multiple pressure chambers 4A-4E is blank discharged from each nozzle 2A-2E is greater for the near-distance pressure chambers than for the far-distance pressure chambers. Specifically, the control unit 600 controls the drive waveform applied to each piezoelectric element 5 during the blank discharge operation so that the number of blank discharges or blank discharge frequency within a predetermined blank discharge period, the amount of liquid discharged per blank discharge, etc. are greater for the near-distance pressure chambers than for the far-distance pressure chambers. Specifically, this control of the drive waveform includes control to change the absolute value, waveform, number of waveform pulses, etc. of the drive waveform.

[0050] When idle ejection is performed, the liquid in the pressure chambers 4, which has risen in temperature (particularly the liquid near the nozzles in the pressure chambers 4A to 4E), is discharged from the nozzles 2 to the outside, and a relatively low-temperature liquid is supplied from the common flow path 3 into the pressure chambers 4. Therefore, the greater the idle ejection rate of a pressure chamber 4, the lower the temperature of the liquid in the pressure chamber 4 can be. Therefore, by performing liquid flow rate control such that the idle ejection rate is greater for the near-distance pressure chambers than for the far-distance pressure chambers, as in this operation example 1, the temperature of the liquid in the near-distance pressure chambers, which is more likely to rise in temperature due to heat generation by the drive circuit 101, can be lowered more than that of the far-distance pressure chambers. Therefore, it is possible to reduce the temperature difference of the liquid between the far-distance pressure chambers and the near-distance pressure chambers due to heat generation by the drive circuit 101, and it is possible to suppress variation in the amount of liquid ejected between the nozzles.

[0051] FIG. 9A is an explanatory diagram illustrating an example of a configuration for performing a dummy discharge operation. 9(a) is applicable to a line-type device that does not move the liquid ejection head 1. Specifically, at a predetermined idle ejection timing, the idle ejection receiving portion 30 that receives the liquid to be idle-ejected is moved to a position facing the nozzle face of the liquid ejection head 1, and the idle ejection operation is performed.

[0052] FIG. 9(b) is an explanatory diagram illustrating another example of the configuration for performing the dummy discharge operation. 9(b) is applicable to a serial type device that moves the liquid ejection head 1. Specifically, at a predetermined idle ejection timing, the carriage 31 carrying the liquid ejection head 1 is moved to a position facing the idle ejection receiving portion 30 that receives the idle ejected liquid (outside the area where the liquid is ejected onto the recording material), and the idle ejection operation is performed.

[0053] FIG. 9C is an explanatory diagram illustrating yet another example of the configuration for performing the dummy discharge operation. 9(c) is applicable to both line-type devices and serial-type devices. Specifically, within the area where liquid is discharged onto the recording material, a blank discharge receiving section 30 that receives blank discharged liquid is disposed at a position facing the nozzle face of the liquid discharge head 1. The blank discharge operation is performed by setting the timing when the recording material P does not pass through the position facing the nozzle face of the liquid discharge head 1 as the blank discharge timing.

[0054] FIG. 9(d) is an explanatory diagram illustrating yet another example of the configuration for performing the dummy discharge operation. 9(d) is applicable to both line-type devices and serial-type devices. Specifically, the timing when the recording material P passes a position facing the nozzle face of the liquid ejection head 1 is set as the idle ejection timing, and an idle ejection operation is performed such that the idle ejected liquid is received by the recording material P. In this case, it is preferable to idle eject the liquid onto the recording material P so as to form dots that are invisible to the user, for example.

[0055] The idle ejection timing (the timing for implementing liquid flow rate control) may be determined based on the detection results of temperature sensors 32a to 32d (see FIG. 6) serving as temperature detection units provided in the liquid ejection head 1. The temperature sensors used in this case include, for example, temperature sensor 32a provided in the drive circuit 101, which is the heat source itself, temperature sensor 32b provided on the opposite side of the drive circuit 101 across the nozzle formation region, and temperature sensors 32c and 32d provided on the end sides of the nozzle row.

[0056] A specific method for determining the dummy discharge timing based on the detection results of the temperature sensors 32a to 32d is, for example, to determine the dummy discharge timing when the detection results of the temperature sensors 32a to 32d exceed a predetermined threshold value. In this case, the dummy discharge timing can be easily controlled.

[0057] 10(a) and 10(b), the timing at which the time change (gradient θ) of the detection result of the temperature sensor 32a installed in the drive circuit 101, which is the heat source itself, exceeds a predetermined threshold may be set as the idle ejection timing. Note that, for example, a sensor that detects the temperature from the temperature characteristics of a resistor element in the drive circuit 101 may be used as such a temperature sensor 32a.

[0058] According to this method, the timing when the temperature of the drive circuit 101 rises suddenly can be set as the idle ejection timing. When the temperature of the drive circuit 101 rises suddenly, the temperature of the liquid in the near pressure chambers close to the drive circuit 101 rises immediately, but the temperature of the liquid in the far pressure chambers far from the drive circuit 101 does not rise immediately, and the temperature difference of the liquid between the near pressure chambers and the far pressure chambers becomes large. Therefore, by setting the timing when the temperature of the drive circuit 101 rises suddenly as the idle ejection timing, the temperature difference of the liquid between the near pressure chambers and the far pressure chambers can be suppressed.

[0059] 11, the timing at which the difference between the detection results of temperature sensor 32a installed on drive circuit 101 and temperature sensor 32b installed on the opposite side of drive circuit 101 across nozzle formation region E exceeds a predetermined threshold may be used as the blank ejection timing. According to this method, the temperature difference of the liquid between the near-distance pressure chamber close to drive circuit 101 and the far-distance pressure chamber far from drive circuit 101 can be detected with high accuracy. Therefore, the blank ejection operation that suppresses this temperature difference can be performed at more appropriate timing.

[0060] Alternatively, for example, a method may be used in which the timing at which the difference in the detection results between temperature sensors 32c and 32d located at each end of the nozzle row exceeds a predetermined threshold value is determined as the idle ejection timing, as shown in Fig. 12. Even between pressure chambers that are the same distance from the drive circuit 101 (for example, between pressure chambers corresponding to nozzles in the same nozzle row), deviations in the liquid temperature may occur.

[0061] 13 , for example, when a liquid supply port 33 that supplies liquid to the common flow channel 3 is connected to the common flow channel 3 at one end of the nozzle row, the pressure chambers corresponding to the nozzles close to the liquid supply port 33 are supplied with liquid (relatively low-temperature liquid) that has just been supplied to the common flow channel 3. On the other hand, the pressure chambers corresponding to the nozzles far from the liquid supply port 33 are supplied with liquid that has remained in the common flow channel 3 for a relatively long time (relatively high-temperature liquid that has been warmed in the common flow channel). As a result, a temperature difference may occur between the pressure chambers corresponding to the nozzles close to the liquid supply port 33 (pressure chambers at one end of the nozzle row), i.e., the pressure chambers corresponding to the upstream side in the direction of liquid flow in the common flow channel 3, and the pressure chambers corresponding to the nozzles far from the liquid supply port 33 (pressure chambers at the other end of the nozzle row), i.e., the pressure chambers corresponding to the downstream side in the direction of liquid flow in the common flow channel 3.

[0062] Therefore, by setting the timing when the difference value of the detection results between the temperature sensors 32c and 32d located at each end of the nozzle row exceeds a predetermined threshold as the idle ejection timing, it is possible to suppress the temperature difference of the liquid that may occur even between pressure chambers that are the same distance from the drive circuit 101 (for example, between pressure chambers corresponding to each nozzle in the same nozzle row).

[0063] Furthermore, the idle ejection timing (the timing for performing the liquid flow rate control) may be, for example, the timing before the start of the liquid ejection operation (printing operation) that ejects liquid onto the recording material P. By performing an idle ejection operation that suppresses the temperature difference of the liquid between the pressure chambers before the start of the liquid ejection operation (printing operation), it is possible to suppress the temperature difference (temperature difference history) of the liquid between the pressure chambers that occurred due to the liquid ejection operation (printing operation) that was performed in the past, and to start the liquid ejection operation (printing operation) in a state where the variation in the amount of liquid ejected between the nozzles is suppressed.

[0064] Furthermore, the idle ejection timing (the timing for performing liquid flow rate control) may be, for example, the timing after the end of a liquid ejection operation (printing operation) in which liquid is ejected onto the recording material P. By performing an idle ejection operation that suppresses the temperature difference of the liquid between the pressure chambers after the end of the liquid ejection operation (printing operation), it is possible to suppress the temperature difference (temperature difference history) of the liquid between the pressure chambers that has occurred due to the current liquid ejection operation (printing operation), and to start the next liquid ejection operation (printing operation) in a state in which the variation in the amount of liquid ejected between the nozzles has been suppressed.

[0065] Furthermore, the idle discharge timing (the timing for carrying out the liquid flow rate control) may be, for example, a timing during the liquid discharge operation (printing operation) of discharging liquid onto the recording material P. Specifically, for example, the idle discharge operation may be performed every time a predetermined amount of time has elapsed during the printing operation, or the printing operation onto the recording material P may be interrupted midway to perform the idle discharge operation.

[0066] Further, examples of timings in the middle of a printing operation where the idle discharge timing is performed include timings between recording materials P (between sheets) during continuous printing (during operation of continuously printing on multiple sheets of recording material P), blank areas at the leading or trailing end of the recording material P in the conveyance direction, and between pages (parts that will be cut later) when the recording material P is roll paper. In these cases, the idle discharge operation can be performed without interrupting the printing operation on the recording material P.

[0067] Furthermore, the drive waveform (drive signal) used in the blank discharge operation may be the same as the drive waveform (drive signal) used in the printing operation, or may be different (dedicated to blank discharge). When a drive waveform (drive signal) dedicated to blank discharge is used, it is possible to discharge faster than during printing operation in order to shorten the time required for blank discharge, or to increase or decrease the amount of liquid discharged compared to during printing operation. On the other hand, when the same drive waveform (drive signal) as during printing operation is used, it is possible to perform the blank discharge operation without impeding the printing operation or printing speed, for example, when performing the blank discharge operation in the middle of a printing operation.

[0068] The long-distance pressure chambers and short-distance pressure chambers that have different idle ejection volumes may, for example, be configured such that only the pressure chamber 4A closest to the drive circuit 101 is a short-distance pressure chamber and the remaining pressure chambers 4B to 4E are long-distance pressure chambers, or the two pressure chambers 4A, 4B closest to the drive circuit 101 are short-distance pressure chambers and the remaining pressure chambers 4C to 4E are long-distance pressure chambers, or any other combination may be used.

[0069] In this way, the five pressure chambers 4A to 4E that are at different distances from the drive circuit 101 may be divided into three or more sections instead of two sections, long-distance pressure chambers and short-distance pressure chambers. For example, the amount of dummy discharge of the liquid in the five pressure chambers 4A to 4E from each nozzle 2A to 2E may be made different for each of the five pressure chambers 4A to 4E so that the dummy discharge amount increases as the distance from the drive circuit 101 decreases.

[0070] [Operation example 2] Next, another example of controlling the liquid flow rate of the plurality of pressure chambers 4A to 4E in this embodiment (hereinafter, this example will be referred to as "Operation Example 2") will be described. In the liquid flow rate control of Operation Example 2, the drive waveform is controlled so that the liquid flow rate during micro-driving, in which the liquid in the multiple pressure chambers 4A to 4E flows without being discharged from the multiple nozzles 2A to 2E, is greater in the near-distance pressure chambers than in the far-distance pressure chambers. In other words, the drive waveform is controlled so that the piezoelectric element 5 is driven (micro-driving) to an extent that the liquid is not ejected from the nozzle 2, and the liquid in the pressure chamber 4 is moved (agitated).

[0071] When the liquid flow rate control of Operation Example 2 is performed, the liquid in the pressure chambers 4 is vibrated by the micro-driving of the piezoelectric element 5, and the liquid in the pressure chambers 4A to 4E is agitated. This allows the liquid near the nozzles, which is particularly difficult to flow in the pressure chambers 4A to 4E when not driven, to be replaced, and the temperature of the liquid ejected from the nozzles (liquid near the nozzles in the pressure chambers 4A to 4E) can be lowered. In particular, when combined with the pressure chamber circulation configuration described below, the liquid far from the nozzles in the pressure chambers 4A to 4E (liquid close to the inlets and outlets of the pressure chambers 4A to 4E), which is agitated and heated by the liquid flow rate control of Operation Example 2, is circulated by the pressure chamber circulation configuration. The circulation in the pressure chamber circulation configuration discharges the heated liquid in the pressure chambers 4A to 4E and supplies relatively low-temperature liquid, thereby enhancing the effect of lowering the temperature by the liquid flow rate control of Operation Example 2.

[0072] Therefore, as in Operation Example 2, by implementing liquid flow rate control that increases the liquid flow rate (liquid exchange rate) during micro-driving in the near-distance pressure chamber compared to the far-distance pressure chamber, it is possible to lower the temperature of the liquid in the near-distance pressure chamber, which is prone to temperature rise due to heat generated by the drive circuit 101, below that of the far-distance pressure chamber. Therefore, it is possible to reduce the temperature difference in the liquid that occurs between the far-distance pressure chamber and the near-distance pressure chamber due to heat generated by the drive circuit 101, and it is possible to suppress variation in the amount of liquid ejected between the nozzles.

[0073] Specifically, the control of the amount of liquid flow (amount of liquid exchange) during micro-driving of the piezoelectric element 5 is performed by controlling the drive waveform applied by the control unit 600 to each piezoelectric element 5 so that the number of micro-driving operations or frequency of operations, the strength of the micro-driving (amount of displacement of the piezoelectric element 5), etc. are greater in the near-distance pressure chamber than in the far-distance pressure chamber.

[0074] According to this operation example 2, no liquid is consumed when controlling the liquid flow rate, so the amount of liquid consumed can be reduced. Furthermore, the drive waveform applied to the piezoelectric element 5 when controlling the liquid flow rate can be a low voltage required for fine driving, so power consumption can also be kept low.

[0075] The timing of the minute drive (the timing of performing the liquid flow rate control) can be the same as the timing of the idle ejection described in the above-mentioned Operation Example 1. Also, as in the above-mentioned Operation Example 1, the five pressure chambers 4A to 4E, which are at different distances from the drive circuit 101, may be divided into two sections, namely, long-distance pressure chambers and short-distance pressure chambers, or may be divided into three or more sections.

[0076] [Operation example 3] Next, still another example of controlling the liquid flow rate of the plurality of pressure chambers 4A to 4E in this embodiment (hereinafter, this example will be referred to as "Operation Example 3") will be described. The liquid flow rate control in this operation example 3 controls the drive waveform so that the liquid discharge rate when discharging liquid onto the recording material P, which is the discharge medium (during printing operation), is greater from the near-distance pressure chamber than from the far-distance pressure chamber. In other words, the drive waveform is controlled so that the image formation contribution rate (number of discharged droplets) during image formation by printing operation is greater from the near-distance pressure chamber than from the far-distance pressure chamber.

[0077] Specifically, when the control unit 600 generates a control signal to input to the head driving unit 20 from the image data, the control signal is generated so that the nozzles 2 corresponding to the short-distance pressure chambers are used more frequently than the nozzles 2 corresponding to the long-distance pressure chambers. Alternatively, the control unit 600 performs a conversion process on the input image data so that the nozzles 2 corresponding to the short-distance pressure chambers are used more frequently than the nozzles 2 corresponding to the long-distance pressure chambers. As a result, the head driving unit 20 to which this control signal is input causes the driving circuit 101 to output a driving waveform such that the amount of liquid ejected onto the recording material P during printing operation is greater from the short-distance pressure chambers than from the long-distance pressure chambers.

[0078] In particular, this Operation Example 3 can more effectively suppress variations in the amount of liquid ejected between the nozzles due to differences in the temperature of the liquid between the pressure chambers by combining it with the above-mentioned Operation Examples 1 and 2. Note that, as in the above-mentioned Operation Examples 1 and 2, the five pressure chambers 4A to 4E, which are at different distances from the drive circuit 101, may be divided into two sections, long-distance pressure chambers and short-distance pressure chambers, or may be divided into three or more sections.

[0079] In this embodiment, the liquid supplied from the liquid supply port 33 to the common flow channel 3 is discharged only to each pressure chamber 4 in a non-circulation configuration. However, as shown in FIG. 14 , a circulation configuration (common flow channel circulation means) that circulates the liquid within the common flow channel 3 may be employed. Specifically, the common flow channel 3 is provided with a liquid supply port 33 and a liquid discharge port 34, and the liquid discharged from the liquid discharge port 34 is returned to the liquid supply port 33. This results in a circulation configuration in which the liquid supplied from the liquid supply port 33 and flowing through the common flow channel 3 without being supplied to the pressure chambers 4 is discharged from the liquid discharge port 34 and returns to the liquid supply port 33. By employing such a liquid circulation configuration for the common flow channel 3, the liquid within the common flow channel 3 is maintained at a relatively low temperature by circulation. As a result, the effect of suppressing the temperature difference of the liquid between the pressure chambers by the liquid flow rate control described above is enhanced.

[0080] 14, a fluid resistance portion 35 is formed between the common flow path 3 and each pressure chamber 4. This fluid resistance portion 35 is effective in suppressing crosstalk between the pressure chambers 4, but it also makes it difficult for temperature to propagate through the liquid between the pressure chambers 4, which can be a factor in increasing the temperature difference in the liquid between the pressure chambers 4 due to heat generation by the drive circuit 101. According to this embodiment, even in a configuration that includes such a fluid resistance portion 35, that is, a configuration in which the temperature difference in the liquid between the pressure chambers 4 is likely to increase due to heat generation by the drive circuit 101, it is possible to reduce the temperature difference by controlling the liquid flow rate as described above.

[0081] 15, the present embodiment may employ a pressure chamber circulation configuration (pressure chamber circulation means) in which the common flow path 3 is divided into a supply common flow path 3A and a discharge common flow path 3B, and each pressure chamber 4 is connected to both the supply common flow path 3A and the discharge common flow path 3B. According to the pressure chamber circulation configuration, the liquid supplied from the supply common flow path 3A to the pressure chamber 4 is discharged from the pressure chamber 4 to the discharge common flow path 3B, except for the liquid discharged (ejected) from the nozzle 2. This generates a flow of liquid inside the pressure chamber 4 from the supply common flow path 3A side to the discharge common flow path 3B side, and the temperature of the liquid inside the pressure chamber 4 can be lowered.

[0082] By adopting such a pressure chamber circulation configuration and setting a high liquid circulation flow rate, temperature differences in the liquid between pressure chambers are unlikely to occur. However, depending on the user's operating environment and control operation settings, printing operations may be performed with the pressure chamber circulation function stopped or the liquid circulation flow rate reduced during printing. This is because controlling pressure fluctuations through liquid circulation is technically difficult, and pressure fluctuations during printing operations cause fluctuations in image density and degrade image quality. In this case, even if a pressure chamber circulation configuration is adopted, the liquid temperature is more likely to rise in close-distance pressure chambers, which are closer to the drive circuit 101, than in far-distance pressure chambers, which are farther away from the drive circuit 101. Therefore, it is preferable to perform the liquid flow rate control described above.

[0083] Furthermore, in this embodiment, the nozzle plate vibration method in which the piezoelectric element 5 is provided on the nozzle forming wall of the pressure chamber 4 has been described as an example, but the piezoelectric element 5 may be provided on a wall portion other than the nozzle forming wall of the pressure chamber 4. For example, as shown in Fig. 16, the piezoelectric element 5 may be arranged on a vibration plate 103 provided on the side of the pressure chamber 4 facing the nozzle forming wall.

[0084] 16, in a configuration in which the piezoelectric element 5 and the drive circuit 101 are formed on the same pressure chamber substrate 100, as described above, the heat generated by the drive circuit 101 has a significant effect on the temperature rise of the liquid in the pressure chambers 4A-4E corresponding to the piezoelectric elements 5A-5E. Therefore, while a far-distance pressure chamber (e.g., pressure chamber 4E) that is located a large distance from the drive circuit 101 is less susceptible to the heat generated by the drive circuit 101, a near-distance pressure chamber (e.g., pressure chamber 4A) that is located a small distance from the drive circuit 101 is more susceptible to the heat generated by the drive circuit 101. As a result, the temperature difference in the liquid tends to be large between the far-distance pressure chamber and the near-distance pressure chamber that are located at different distances from the drive circuit 101, causing variations in the liquid ejection volume between the nozzles corresponding to the far-distance pressure chamber and the near-distance pressure chamber. Therefore, the liquid flow volume control described above is effective.

[0085] Next, an example of a liquid ejection device according to the present invention will be described with reference to FIGS. FIG. 17 is a schematic explanatory diagram of a printing apparatus that is an inkjet recording apparatus, which is an image forming apparatus serving as a device that ejects liquid in this embodiment. FIG. 18 is an explanatory plan view of an example of a head unit of a printing apparatus according to this embodiment.

[0086] A printing apparatus 500, which is an apparatus for ejecting this liquid, includes a carry-in means 501 that carries in a continuum 510, and a guide / conveyance means 503 that guides and conveys the continuum 510 carried in from the carry-in means 501 to a printing means 505. The printing apparatus 500 also includes a printing means 505 that ejects a liquid onto the continuum 510 to form an image, a drying means 507 that dries the continuum 510, and an ejection means 509 that ejects the continuum 510.

[0087] The continuous web 510 is sent out from a main winding roller 511 of the carry-in means 501, guided and conveyed by the rollers of the carry-in means 501, the guide and conveying means 503, the drying means 507, and the conveying means 509, and wound up by a winding roller 591 of the conveying means 509. In the printing means 505, the continuous web 510 is conveyed on a conveying guide member 559 opposite the head unit 550, and an image is printed by liquid ejected from the head unit 550.

[0088] In the printing device 500 of this embodiment, the head unit 550 includes the two head modules 100A and 100B according to this embodiment described above, mounted on a common base member 552.

[0089] When the direction in which the liquid ejection heads 1 of the head modules 100A and 100B are lined up in a direction perpendicular to the transport direction is defined as the head arrangement direction, the head arrays 1A1 and 1A2 of the head module 100A eject liquid of the same color. Similarly, the head arrays 1B1 and 1B2 of the head module 100A are paired, the head arrays 1C1 and 1C2 of the head module 100B are paired, and the head arrays 1D1 and 1D2 are paired, and each ejects liquid of the required color.

[0090] Next, another example of a printing apparatus as a liquid ejecting apparatus according to the present invention will be described with reference to FIGS. 19 and 20. FIG. FIG. 19 is an explanatory plan view of the main parts of the printing apparatus of this example. FIG. 20 is an explanatory side view of the main part of the printing apparatus of this example.

[0091] The printing apparatus 500 of this example is a serial type apparatus, and a carriage 403 is moved back and forth in the main scanning direction by a main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is hung between left and right side plates 491A and 491B to movably hold the carriage 403. The main scanning motor 405 then moves the carriage 403 back and forth in the main scanning direction via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

[0092] This carriage 403 is equipped with a liquid ejection unit 440 that integrates the liquid ejection head 1 according to the present invention and a head tank 441. The liquid ejection head 1 ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid ejection head 1 is mounted with a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward. The liquid ejection head 1 is connected to a liquid circulation device, which circulates and supplies liquid of the required color.

[0093] The printing apparatus 500 is equipped with a transport mechanism 495 for transporting paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412. The transport belt 412 attracts the paper 410 and transports it at a position facing the liquid ejection head 1. The transport belt 412 is an endless belt that is stretched between a transport roller 413 and a tension roller 414. The attraction can be achieved by electrostatic attraction or air suction. The transport belt 412 moves in a circular motion in the sub-scanning direction as the transport roller 413 is rotationally driven by the sub-scanning motor 416 via a timing belt 417 and a timing pulley 418.

[0094] Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head 1 is disposed on one side of the carriage 403 in the main scanning direction, beside the conveyor belt 412. The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface of the liquid ejection head 1, a wiper member 422 that wipes the nozzle surface, and the like. The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the conveyor mechanism 495 are attached to a housing that includes side plates 491A and 491B and a back plate 491C.

[0095] In the printing device 500 configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereon, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412. Then, by driving the liquid ejection head 1 in accordance with an image signal while moving the carriage 403 in the main scanning direction, liquid is ejected onto the stationary paper 410 to form an image.

[0096] Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 21 is a plan view illustrating the main parts of the liquid discharge unit of this example.

[0097] This liquid ejection unit 440 is composed of the components that make up the device for ejecting the liquid, including a housing portion consisting of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 1.

[0098] It is also possible to configure a liquid discharge unit in which the above-described maintenance and recovery mechanism 420 is further attached to, for example, the side plate 491B of this liquid discharge unit 440.

[0099] Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 22 is an explanatory front view of the liquid discharge unit of this example.

[0100] This liquid discharge unit 440 is composed of a liquid discharge head 1 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444 .

[0101] The flow path part 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path part 444. A connector 443 for electrically connecting with the liquid ejection head 1 is provided on the upper part of the flow path part 444.

[0102] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited. However, it is preferable that the viscosity of the liquid be 30 mPa·s or less at room temperature and normal pressure, or upon heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, or the like containing a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant. These liquids can be used, for example, in inkjet inks, surface treatment solutions, liquids for forming components of electronic devices or light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D modeling.

[0103] The liquid to be ejected may be a metal material such as solder or a material that is fixed at room temperature, such as wax ink, that is heated and melted before being ejected from the nozzle. Alternatively, the liquid to be ejected may be a liquid that has a high viscosity at room temperature, such as UV ink, that is heated to reduce its viscosity before being ejected from the nozzle. In this case, by providing a heating means such as a heater in the nozzle plate 110, the ejection material in the pressure chamber 4 can be melted or reduced in viscosity, allowing the liquid to be ejected smoothly from the nozzle.

[0104] A "liquid ejection unit" is a liquid ejection head integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a liquid ejection head combined with at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.

[0105] Here, "integrated" includes, for example, a liquid ejection head and a functional part or mechanism that are fixed to each other by fastening, bonding, engaging, etc., or one that is held movably relative to the other. The liquid ejection head, functional part, or mechanism may also be configured to be detachable from each other.

[0106] For example, some liquid ejection units have a liquid ejection head and a head tank integrated together, while others have a liquid ejection head and a head tank integrated together by being connected to each other by a tube, etc. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

[0107] Furthermore, there is a liquid ejection unit in which the liquid ejection head and the carriage are integrated.

[0108] In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated together. In other liquid ejection units, the liquid ejection head, the carriage, and the main scanning movement mechanism are integrated together.

[0109] Furthermore, there is a liquid ejection unit in which a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which a liquid ejection head is attached, thereby integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

[0110] In some liquid ejection units, a tube is connected to a head tank or a liquid ejection head equipped with a flow path component, integrating the liquid ejection head with a supply mechanism. Liquid is supplied from a liquid reservoir to the liquid ejection head via this tube.

[0111] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0112] Here, the "liquid ejection unit" is described in combination with a liquid ejection head, but the "liquid ejection unit" also includes a head module or head unit that includes the liquid ejection head described above, and that integrates the functional components and mechanisms described above.

[0113] "Liquid ejection devices" include devices that are equipped with a liquid ejection head, a liquid ejection unit, a head module, a head unit, etc., and that eject liquid by driving the liquid ejection head. Liquid ejection devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0114] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0115] For example, examples of "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed from layers of powder in order to create a three-dimensional object (a three-dimensional model).

[0116] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0117] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, all objects onto which a liquid can adhere are included.

[0118] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0119] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0120] Other examples of "liquid ejecting devices" include treatment liquid application devices that eject 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 spray granulation devices that spray a composition liquid in which raw materials are dispersed through a nozzle to granulate the raw material particles.

[0121] In the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

[0122] The above description is merely an example, and each of the following aspects provides unique effects. [First aspect] The first aspect is a device (e.g., inkjet recording device 10) for ejecting liquid, which includes a liquid ejection head 1 that ejects liquid flowing in from a common flow path 3 from a plurality of nozzles onto an ejection receiving medium (e.g., recording material P) by applying a drive signal from a drive circuit 101 to each electromechanical conversion element (e.g., piezoelectric element 5) that changes the pressure in a plurality of pressure chambers 4 that are respectively connected to a plurality of nozzles 2, from the plurality of nozzles, and is characterized by having a control unit 600 that controls the liquid flow rate of the plurality of pressure chambers so that the liquid flow rate in a close-distance pressure chamber (e.g., pressure chamber 4A) that is located a short distance from the drive circuit is greater than the liquid flow rate in a far-distance pressure chamber (e.g., pressure chamber 4E) that is located a long distance from the drive circuit. Traditionally, the primary heat source affecting the temperature rise of the liquid in the pressure chamber has been an electromechanical transducer such as a piezoelectric element. However, in recent years, other heat sources besides electromechanical transducers have been found to affect the temperature rise of the liquid in the pressure chamber. For example, in nozzle plate vibration-type devices in which a piezoelectric element is provided on the nozzle-forming wall of a pressure chamber connected to a nozzle, a low-piezoelectric constant piezoelectric element may be used as the nozzle density increases. In this case, the heat generated by the piezoelectric element is smaller than that of a high-piezoelectric constant piezoelectric element such as PZT, which is commonly used as an electromechanical transducer. Therefore, other heat sources have a greater impact on the temperature rise of the liquid in the pressure chamber than the heat generated by the piezoelectric element. For example, the heat generated by the drive circuit that applies a drive signal to the piezoelectric element can have a greater impact on the temperature rise of the liquid in the pressure chamber than the heat generated by the piezoelectric element itself. In this case, a distant pressure chamber located a greater distance from the drive circuit is less affected by the heat generated by the drive circuit, while a close pressure chamber located a shorter distance from the drive circuit is more affected by the heat generated by the drive circuit. Therefore, the temperature difference between the liquids is likely to be large between the long-distance pressure chamber and the short-distance pressure chamber, which are spaced apart from the drive circuit by different distances. In this aspect, the liquid flow rate of the multiple pressure chambers is controlled so that the liquid flow rate into the near-distance pressure chamber, which is located a short distance from the drive circuit, is greater than the liquid flow rate into the far-distance pressure chamber, which is located a long distance from the drive circuit. Increasing the liquid flow rate within the pressure chamber promotes agitation of the liquid within the pressure chamber. This, for example, can promote replacement of the liquid near the nozzle, which is particularly difficult to flow within the pressure chamber when not driven, and can lower the temperature of the liquid ejected from the nozzle (the liquid near the nozzle within the pressure chamber). Therefore, with the liquid flow rate control of this aspect, the temperature of the liquid within the near-distance pressure chamber (particularly the temperature of the liquid ejected from the nozzle (the liquid near the nozzle within the pressure chamber)) can be lowered compared to the far-distance pressure chamber. As a result, the temperature difference between the liquid in the far-distance pressure chamber and the near-distance pressure chamber can be reduced, and variation in the liquid ejection rate between the nozzles can be suppressed.

[0123] [Second mode] A second aspect is characterized in that, in the first aspect, the liquid flow rate control includes controlling the drive signal so that the amount of idle ejection of liquid from the plurality of pressure chambers from the plurality of nozzles within a predetermined idle ejection time is greater from the near-distance pressure chambers than from the far-distance pressure chambers. When idle ejection is performed, the liquid in the pressure chamber (liquid near the nozzle in the pressure chamber) whose temperature has risen is discharged from the nozzle to the outside, and relatively low-temperature liquid is supplied to the pressure chamber from the common flow path. Therefore, the greater the idle ejection rate in a pressure chamber, the lower the temperature of the liquid in the pressure chamber can be. Therefore, by implementing liquid flow rate control that increases the idle ejection rate in the near-distance pressure chamber compared to the far-distance pressure chamber, as in this embodiment, the temperature of the liquid in the near-distance pressure chamber, which is more likely to rise in temperature due to heat generation by the drive circuit, can be lowered more than in the far-distance pressure chamber. Therefore, the temperature difference in the liquid that occurs between the far-distance pressure chamber and the near-distance pressure chamber due to heat generation by the drive circuit can be reduced.

[0124] [Third aspect] A third aspect is characterized in that, in the first or second aspect, the liquid flow rate control includes controlling the drive signal so that the liquid flow rate during micro-vibration, in which the liquid in the multiple pressure chambers flows without being discharged from the multiple nozzles, is greater in the near-distance pressure chamber than in the far-distance pressure chamber. When the liquid flow rate control of this embodiment is performed, the liquid in the pressure chamber vibrates due to the micro-drive of the piezoelectric element, and the liquid in the pressure chamber is agitated. This allows the liquid near the nozzle, which is particularly difficult to flow in the pressure chamber when not driven, to be replaced, and the temperature of the liquid ejected from the nozzle (the liquid near the nozzle in the pressure chamber) can be lowered. Therefore, by performing liquid flow rate control such that the liquid flow rate during micro-vibration is greater in the near-distance pressure chamber than in the far-distance pressure chamber, as in this embodiment, the temperature of the liquid in the near-distance pressure chamber, which is more likely to rise in temperature due to heat generated by the drive circuit, can be lowered more than in the far-distance pressure chamber. Therefore, the temperature difference in the liquid between the far-distance pressure chamber and the near-distance pressure chamber due to heat generated by the drive circuit can be reduced.

[0125] [Fourth aspect] A fourth aspect is characterized in that, in any of the first to third aspects, the liquid flow rate control includes controlling the drive signal so that the amount of liquid ejected from the near-distance pressure chamber is greater than that from the far-distance pressure chamber when ejecting liquid onto the ejection medium. When the liquid flow rate control of this aspect is performed, the amount of liquid ejected from the near-distance pressure chamber is greater than that from the far-distance pressure chamber when ejecting liquid onto the ejection receiving medium. The greater the amount of liquid ejected from a pressure chamber, the lower the temperature of the liquid within the pressure chamber can be. Therefore, according to this aspect, the temperature of the liquid in the near-distance pressure chamber, which is prone to temperature increases due to heat generated by the drive circuit, can be lowered more than that of the far-distance pressure chamber. This reduces the temperature difference in the liquid between the far-distance pressure chamber and the near-distance pressure chamber due to heat generated by the drive circuit.

[0126] [Fifth mode] A fifth aspect is characterized in that in any one of the first to fourth aspects, the drive circuit is formed on an actuator substrate (for example, the nozzle plate 110) on which the electromechanical conversion element is formed. In a configuration in which the drive circuit and the electromechanical transducer are formed on the same substrate (actuator substrate), the drive circuit is positioned close to the area where the electromechanical transducer is formed, in order to shorten the wiring length, etc. Therefore, heat generated by the drive circuit can have a significant impact on the temperature rise of the liquid in the pressure chamber corresponding to each electromechanical transducer. Therefore, the temperature difference of the liquid is likely to be large between the far-distance pressure chamber and the near-distance pressure chamber, which are spaced apart from the drive circuit by different distances. This aspect can reduce the temperature difference even when a configuration in which the temperature difference of the liquid between the far-distance pressure chamber and the near-distance pressure chamber is likely to be large is adopted.

[0127] [Sixth aspect] A sixth aspect is characterized in that in any one of the first to fifth aspects, the electromechanical conversion element is a piezoelectric element containing aluminum nitride or aluminum scandium nitride as a main component. When a high-piezoelectric-constant piezoelectric element such as PZT is used as the electromechanical transducer, the heat generated by the piezoelectric element is relatively large among heat sources that can affect the temperature rise of the liquid in each pressure chamber, and the heat generated by the piezoelectric element is dominant in the temperature rise of the liquid in each pressure chamber. However, when the electromechanical transducer is a low-piezoelectric-constant piezoelectric element primarily composed of AlN or ScAlN, as in this embodiment, the heat generated by the piezoelectric element is less than that of a high-piezoelectric-constant piezoelectric element such as PZT. Therefore, heat sources other than the piezoelectric element, such as the heat generated by the drive circuit, can affect the temperature rise of the liquid in each pressure chamber. Therefore, the temperature difference of the liquid is likely to be large between the far-distance pressure chamber and the near-distance pressure chamber, which are spaced apart from the drive circuit by different distances. This embodiment can reduce the temperature difference even when a configuration in which the temperature difference of the liquid between the far-distance pressure chamber and the near-distance pressure chamber is likely to be large is adopted.

[0128] [Seventh aspect] A seventh aspect is characterized in that in any of the first to sixth aspects, the electromechanical conversion element is provided on a nozzle forming wall of the pressure chamber. According to this aspect, in a liquid ejection device that employs a nozzle plate vibration system, it is possible to reduce the temperature difference in liquid that occurs between the long-distance pressure chamber and the short-distance pressure chamber due to heat generation in the drive circuit.

[0129] [Eighth aspect] An eighth aspect is characterized in that in any one of the first to sixth aspects, the electromechanical conversion element is provided on a wall portion of the pressure chamber other than a nozzle forming wall. According to this aspect, for example, in a configuration in which an electromechanical conversion element is arranged on a vibration plate provided on the side opposite the nozzle forming wall of the pressure chamber, the temperature difference in the liquid that occurs between the long-distance pressure chamber and the short-distance pressure chamber due to heat generation by the drive circuit can be reduced.

[0130] [Ninth aspect] A ninth aspect is the liquid ejection device according to any one of the first to eighth aspects, characterized in that it comprises common flow path circulation means for circulating the liquid in the common flow path. According to this aspect, the common flow path circulation means maintains the liquid in the common flow path at a relatively low temperature through circulation, thereby enhancing the effect of suppressing the temperature difference of the liquid between the pressure chambers through the above-mentioned liquid flow rate control.

[0131] [Tenth aspect] A tenth aspect is the liquid ejection device according to any one of the first to ninth aspects, characterized in that it further comprises a pressure chamber circulation means for circulating the liquid in the plurality of pressure chambers. According to this aspect, in a liquid ejection device employing a pressure chamber circulation means, it is possible to reduce the temperature difference of the liquid that occurs between the far-distance pressure chamber and the near-distance pressure chamber due to heat generation in the drive circuit.

[0132] [Eleventh aspect] The eleventh aspect is characterized in that, in any of the first to tenth aspects, the liquid ejection head has a temperature detection unit (temperature sensor 32a to 32d) that detects the temperature at a predetermined location, and the control unit determines the timing of implementing the liquid flow rate control based on the detection result of the temperature detection unit. In this aspect, the timing for implementing the liquid flow rate control is determined based on the detection results of the temperature detection unit, so that the liquid flow rate control can be implemented at an appropriate timing that ensures that the temperature difference of the liquid between the pressure chambers does not exceed the allowable range. [Explanation of symbols]

[0133] 1: Liquid ejection head 2: Nozzle 3: Common flow path 3A: Common supply flow path 3B: Common flow path for discharge 4: Pressure chamber 4a: Opening 5: Piezoelectric element 10: Inkjet recording device 20: Head drive unit 22: Head control unit 30: Empty discharge receiver 31: Carriage 32a to 32d: Temperature sensors 33:Liquid supply port 34:Liquid outlet 35: Fluid resistance section 51:First electrode 52: Piezoelectric film 53:Second electrode 100: Pressure chamber substrate 101: Drive circuit 102:Wiring section 103: Vibration plate 110: Nozzle plate 120: Common channel board 151: First electrode layer 152: Piezoelectric layer 153:Second electrode layer 440: Liquid dispensing unit 500:Printing device 550: Head unit 600: Control unit 610: CPU 620: Storage section 630:RAM 640:ROM 710: Transport drive unit 720: Operation display section 730: Input / output interface 740: Bus Line 800: External device [Prior art documents] [Patent documents]

[0134] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-114106

Claims

1. A liquid ejection device including a liquid ejection head that applies a drive signal from a drive circuit to each of electromechanical conversion elements that change the pressure in a plurality of pressure chambers that are respectively in communication with a plurality of nozzles, thereby ejecting liquid from the plurality of pressure chambers that flows in from a common flow path onto an ejection receiving medium from the plurality of nozzles, A liquid ejection device characterized by having a control unit that controls the liquid flow rate of the multiple pressure chambers so that the liquid flow rate in a close-distance pressure chamber that is located a short distance from the drive circuit is greater than the liquid flow rate in a far-distance pressure chamber that is located a long distance from the drive circuit.

2. 2. The liquid ejection device according to claim 1, The liquid ejection device is characterized in that the liquid flow rate control includes controlling the drive signal so that the amount of idle ejection of the liquid in the plurality of pressure chambers from the plurality of nozzles within a predetermined idle ejection time is greater from the near-distance pressure chamber than from the far-distance pressure chamber.

3. 2. The liquid ejection device according to claim 1, A liquid ejection device characterized in that the liquid flow rate control includes controlling the drive signal so that the liquid flow rate during micro-driving, in which the liquid in the multiple pressure chambers flows without being ejected from the multiple nozzles, is greater in the near-distance pressure chambers than in the far-distance pressure chambers.

4. The liquid ejection device according to any one of claims 1 to 3, A liquid ejection device characterized in that the liquid flow rate control includes controlling the drive signal so that the liquid ejection rate when ejecting liquid onto the ejected medium is greater from the near-distance pressure chamber than from the far-distance pressure chamber.

5. The liquid ejection device according to any one of claims 1 to 3, The liquid ejecting device is characterized in that the drive circuit is formed on an actuator substrate on which the electromechanical conversion element is formed.

6. The liquid ejection device according to any one of claims 1 to 3, A liquid ejection device, wherein the electromechanical conversion element is a piezoelectric element whose main component is aluminum nitride or aluminum scandium nitride.

7. The liquid ejection device according to any one of claims 1 to 3, The liquid ejection device is characterized in that the electromechanical conversion element is provided on a nozzle forming wall of the pressure chamber.

8. The liquid ejection device according to any one of claims 1 to 3, The liquid ejection device is characterized in that the electromechanical conversion element is provided on a wall portion of the pressure chamber other than a nozzle forming wall.

9. The liquid ejection device according to any one of claims 1 to 3, A liquid ejection device comprising: a common flow path circulation means for circulating the liquid in the common flow path.

10. The liquid ejection device according to any one of claims 1 to 3, A liquid ejection device comprising a pressure chamber circulation means for circulating the liquid in the plurality of pressure chambers.

11. The liquid ejection device according to any one of claims 1 to 3, a temperature detection unit that detects the temperature at a predetermined location of the liquid ejection head; The liquid ejection device is characterized in that the control unit determines the timing of implementing the liquid flow rate control based on the detection result of the temperature detection unit.

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