Liquid discharge head, liquid discharge apparatus, and method of controlling liquid discharge apparatus

Abstract

To appropriately control a liquid discharge direction from a nozzle in a configuration in which one pressure chamber is provided for one nozzle.SOLUTION: The liquid ejection head comprises a nozzle 2 for ejecting liquid, a pressure chamber communicating with the nozzle, and actuators provided on a nozzle forming 5A 110 of the pressure chamber wherein the actuators are composed of a plurality of actuators elements side 5B, side wall for generating a biased pressure to a nozzle communication opening on the nozzle forming wall communicating with the nozzle.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head, a liquid ejection device, and a method for controlling a liquid ejection device.

[0002] 2. Description of the Related Art Conventionally, a liquid ejection head is known that includes a nozzle for ejecting liquid, a pressure chamber that communicates with the nozzle, and an actuator that is provided on a nozzle forming wall of the pressure chamber.

[0003] Patent Document 1 discloses an apparatus in which one nozzle is connected to two pressure chambers to prevent image quality degradation, such as white streaks and uneven color density, caused by nozzles (non-ejecting nozzles) that are no longer able to eject liquid due to clogging with dust or other debris. In this apparatus, when the same voltage is applied at the same time to the pressure-generating elements (actuator elements) arranged in the two pressure chambers, the nozzle ejects liquid in a direction perpendicular to the nozzle surface. On the other hand, when different voltages are applied to the pressure-generating elements of the two pressure chambers, the ejection direction of the liquid ejected from the nozzle can be directed in a direction oblique to the direction perpendicular to the nozzle surface. This prevents image quality degradation, such as white streaks and uneven color density, by causing liquid ejected from another nozzle to land in an oblique direction at the position where liquid from the non-ejecting nozzle lands. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional devices, there is a problem in that it is necessary to provide two pressure chambers for one nozzle in order to control the direction in which liquid is ejected from the nozzle. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a liquid ejection head comprising a nozzle for ejecting liquid, a pressure chamber connected to the nozzle, and an actuator provided in a nozzle forming wall of the pressure chamber, wherein the actuator is composed of a plurality of actuator elements that generate biased pressure in different regions within the pressure chamber relative to a nozzle communication opening on the nozzle forming wall that communicates with the nozzle. [Effects of the Invention]

[0006] According to the present invention, in a configuration in which one pressure chamber is provided for one nozzle, it is possible to control the direction in which liquid is ejected from the nozzle. [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] 2 is an enlarged cross-sectional view of a portion surrounded by a dashed line indicated by the symbol X in FIG. 1 in a modified example. [Figure 5] FIG. 2 is a plan view schematically showing the internal structure of the liquid ejection head, and is a cross-sectional view taken along the line CC'. [Figure 6] FIG. 2 is a front view schematically showing the internal structure of the liquid ejection head, and is a cross-sectional view taken along the line AA'. [Figure 7] FIG. 2 is a side view schematically showing the internal structure of the liquid ejection head, and is a cross-sectional view taken along the line BB'. [Figure 8] FIG. 2 is a schematic diagram showing an example of a piezoelectric element according to an embodiment. [Figure 9] 1A is a schematic diagram showing another example of the piezoelectric element according to the embodiment, and FIG. 1B is a schematic diagram showing yet another example of the piezoelectric element according to the embodiment. [Figure 10](a) is an explanatory diagram showing the liquid ejection direction when performing normal ejection, (b) is an explanatory diagram showing an example of a drive voltage applied to the left piezoelectric element when performing normal ejection, and (c) is an explanatory diagram showing an example of a drive voltage applied to the right piezoelectric element when performing normal ejection. [Figure 11] (a) is an explanatory diagram showing the liquid ejection direction when ejecting liquid obliquely to the right in the figure with respect to the perpendicular direction to the nozzle face. (b) is an explanatory diagram showing an example of the drive voltage applied to the left piezoelectric element when ejecting liquid obliquely to the right in the figure with respect to the perpendicular direction to the nozzle face. (c) is an explanatory diagram showing an example of the drive voltage applied to the right piezoelectric element when ejecting liquid obliquely to the right in the figure with respect to the perpendicular direction to the nozzle face. [Figure 12] (a) is a diagram showing the pressure fluctuations inside the pressure chamber when drive voltages with the same drive waveform are applied to the left and right piezoelectric elements (in the case of normal ejection), and (b) is a diagram showing the pressure fluctuations inside the pressure chamber when drive voltage is applied only to the left piezoelectric element and not to the right piezoelectric element (in the case of oblique ejection). [Figure 13] (a) is a diagram showing the results of numerical calculations of the liquid ejection direction when drive voltages with the same drive waveform are applied to the left and right piezoelectric elements (normal ejection), and (b) is a diagram showing the results of numerical calculations of the liquid ejection direction when drive voltage is applied only to the left piezoelectric element and not to the right piezoelectric element (oblique ejection). [Figure 14] (a) is a graph showing the results of numerical calculations of the liquid ejection angle when the drive voltage applied only to the left piezoelectric element is set to 340 V. (b) is a graph showing the results of numerical calculations of the liquid ejection angle when the drive voltage applied only to the left piezoelectric element is set to 400 V. [Figure 15] FIG. 10 is an explanatory diagram showing a conventional general non-ejecting nozzle compensation control. [Figure 16] 10A and 10B are explanatory diagrams showing an example of non-ejecting nozzle complement control in Operation Example 1. [Figure 17] 10A and 10B are explanatory diagrams showing another example of non-ejecting nozzle complement control in Operation Example 1. [Figure 18]FIG. 10 is an explanatory diagram showing an example of non-ejecting nozzle complementary control in which nine adjacent nozzles surrounding a non-ejecting nozzle are used as complementary nozzles. [Figure 19] FIG. 10 is an explanatory diagram showing yet another example of non-ejecting nozzle supplementary control in Operation Example 1. [Figure 20] FIG. 10 is an explanatory diagram showing a control block relating to non-ejection nozzle complement control in Operation Example 1. [Figure 21] 10A is an explanatory diagram showing the ejection direction of droplets ejected from a defective nozzle when the ejection deflection correction control of Operation Example 2 is not performed, and FIG. 10B is an explanatory diagram showing the ejection direction of droplets ejected from a defective nozzle when the ejection deflection correction control of Operation Example 2 is performed. [Figure 22] FIG. 1 is a schematic diagram illustrating a printing apparatus according to an embodiment. [Figure 23] FIG. 2 is an explanatory plan view of an example of a head unit of the printing apparatus. [Figure 24] FIG. 10 is an explanatory plan view of the main parts of another printing device. [Figure 25] FIG. 2 is a side view illustrating the main parts of the printing apparatus of the present embodiment. [Figure 26] FIG. 2 is a plan view illustrating a main part of the liquid ejection unit according to the embodiment. [Figure 27] 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 a liquid ejection head provided in 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 actuator provided in 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 building wiring and drive circuits within the substrate, wiring can be laid out even in configurations with high nozzle density. Lead zirconate titanate (PZT) is commonly used as the piezoelectric material for actuators due to its high piezoelectric properties. However, when forming a piezoelectric film on a substrate containing wiring and drive circuits, PZT requires a deposition and crystallization temperature of 600°C or higher. Therefore, using PZT as the piezoelectric material would prevent the drive circuits and their wiring within the substrate from withstanding such high temperatures. Therefore, in configurations where wiring and drive circuits are built within the substrate, a piezoelectric material with a lower deposition temperature than PZT is required, forcing the selection of a material with lower piezoelectric properties than PZT. However, the nozzle plate vibration method described above has the advantage of ejecting droplets with less force than a typical unimorph piezo head, so it is possible to achieve good liquid ejection even with a material with lower piezoelectric properties than PZT. Therefore, even lead-free piezoelectric materials, which have low film formation and crystallization temperatures but low power, can eject liquid effectively. This allows wiring and drive circuits to be built inside the substrate, enabling higher density. Furthermore, the nozzle plate vibration method allows the volume of the pressure chamber to be reduced, making it possible to miniaturize the head.

[0011] 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 comprises a nozzle plate 110, a pressure chamber substrate 100, and a fluid resistance substrate 120. In addition, the liquid ejection head 1 also comprises a frame portion 140 and the like, as will be described later.

[0012] 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 and are arranged around the nozzles 2. The pressure chamber substrate 100 has a plurality of pressure chambers (also referred to as individual liquid chambers or pressurized liquid chambers) 4 that respectively communicate with the plurality of nozzles 2. The nozzles 2 (vibration membranes 103) are located on one side of each pressure chamber 4, and the fluid resistance substrate 120 and its openings 4a are located on the side opposite this surface. The frame portion 140 has a common liquid chamber 3 that communicates with the plurality of pressure chambers 4 via the openings 4a. Electrical connection pads 55 are provided on both ends of the liquid ejection head 1 for connection to electrical components such as an external power source.

[0013] 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 has a drive circuit 101 and a wiring section 102 on the side where the vibrating membrane 103 is formed. The drive circuit 101 is a circuit including transistors, resistors, etc. The wiring section 102 has a wiring section connected to the first electrode 51 (also referred to as a common electrode) and a wiring section for applying a drive voltage (drive waveform) to the second electrode 53 (also referred to as an individual electrode). The wiring section 102 is also electrically connected to an electrical connection pad 55 via a third contact 7c opened in the vibrating membrane 103.

[0014] 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.

[0015] The piezoelectric element 5 of the nozzle plate 110 has a first electrode 51, a piezoelectric film 52, and a second electrode 53. The piezoelectric element 5 is covered with a first insulating film 8a. 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 are formed in the first insulating film 8a.

[0016] 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.

[0017] 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.

[0018] It is also possible to provide lead wiring portions for the first electrode 51 and the second electrode 53, respectively, and connect them directly to the wiring portion 102 in an electrode manner via contacts opened in the vibration membrane. Also, an adhesion improving film for ensuring adhesion with the nozzle forming portion 111 may be formed on the second insulating film 8b.

[0019] The liquid filling the liquid ejection head 1 enters the nozzle 2 and forms a meniscus inside the nozzle. By applying a predetermined drive voltage to each of the electrodes 51 and 53 of the piezoelectric element 5, the piezoelectric film 52 is displaced (vibrates), and the vibrating film 103 vibrates in the vertical direction in Figure 3. 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.

[0020] 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 liquid chamber 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 circumferential 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 SiO2, and Ta, which has a valence close to or slightly different from those, are particularly desirable.

[0025] 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.

[0026] In this embodiment, a lyophilic protective film 11 is also formed on the surface of the pressure chamber substrate 100 opposite the film-forming surface of the vibration membrane 103, which constitutes the bottom surface of the common liquid chamber 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 liquid chamber 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 surfaces 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 liquid chamber 3, the liquid can more easily wet and spread across the bottom surface of the common liquid chamber 3, thereby improving the liquid filling performance. For this reason, it is preferable to form a lyophilic protective film 11 on the surface of the pressure chamber substrate 100 opposite the film-forming surface of the vibration membrane 103, which constitutes the bottom surface of the common liquid chamber 3.

[0027] 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.

[0028] The first electrode layer 151 and the second electrode layer 153 are preferably made of a metal with low electrical resistance and low reactivity, such as Ir or Mo. When the drive circuit 101 and wiring section 102 are built into the pressure chamber substrate 100 to improve density, as in this embodiment, the piezoelectric material that makes up the piezoelectric layer 152 is preferably a piezoelectric material whose film formation temperature is 450°C or less to prevent them from being damaged. Examples of piezoelectric materials whose film formation temperature is 450°C or less include AlN and ScAlN, which has a higher piezoelectric constant than AlN.

[0029] Furthermore, using ScAlN as the piezoelectric material offers the following advantage. Although the piezoelectric properties can be improved by aligning the crystal orientation of piezoelectric film 52, an orientation control layer must be provided between vibrating film 103 and first electrode 51 to control the orientation. When the piezoelectric material of piezoelectric film 52 is ScAlN, using ScAlN as the orientation control layer also makes it possible to bring the lattice constant of first electrode 51, which is made of Mo, closer to that of ScAlN. As a result, the crystal orientation of piezoelectric film 52 is aligned, enabling improved piezoelectric properties.

[0030] In this embodiment, the fluid resistance substrate 120 is used to provide a fluid resistance portion that narrows the opening 4a between each pressure chamber 4 and the common liquid chamber 3. However, a configuration without the fluid resistance substrate 120 and without a fluid resistance portion is also possible. However, in this embodiment, since the pressure chambers are arranged closely together at a high density, the pressure generated during liquid ejection is likely to propagate to adjacent pressure chambers 4 and affect the liquid ejection from the nozzle 2 of the adjacent pressure chamber 4. By providing a fluid resistance portion as in this embodiment, such an effect can be suppressed. Note that, as shown in FIG. 4, multiple fluid resistance portions (openings 4a) may be provided for one pressure chamber 4.

[0031] FIG. 5 is a plan view schematically showing the internal structure of the liquid ejection head 1 in this embodiment, and is a cross-sectional view taken along the line CC'. FIG. 6 is a front view schematically showing the internal structure of the liquid ejection head 1 in this embodiment, and is a cross-sectional view taken along the line AA'. FIG. 7 is a side view, taken along the line BB', that schematically shows the internal structure of the liquid ejection head 1 of this embodiment.

[0032] As shown in FIGS. 6 and 7, the liquid ejection head 1 of this embodiment is configured by arranging a nozzle plate 110, a pressure chamber substrate 100, a fluid resistance substrate 120, and a frame portion 140 in this order.

[0033] The pressure chamber substrate 100 has a pressure chamber array 40, which is an area where a plurality of pressure chambers 4 are arranged. Openings 4a of the fluid resistance substrate 120 are formed on the upper surface (the surface on the common liquid chamber 3 side) of the pressure chamber array 40, and the common liquid chambers 3 formed in the frame portion 140 are arranged so as to face the openings 4a of the fluid resistance substrates 120. In this embodiment, as an example, the dimension of the pressure chambers 4 is 220 μm, and the width of the partition walls that separate the pressure chambers 4 is 30 μm, and as a result, the center-to-center distance L2 (see FIG. 7) between two adjacent pressure chambers 4 is 250 μm.

[0034] Liquid stored in an external liquid storage unit is supplied to the liquid ejection head 1 via a liquid supply port 33 in the frame unit 140. The liquid supplied from this liquid supply port 33 is supplied to the common liquid chamber 3, and from the common liquid chamber 3 to each pressure chamber 4 via the openings 4a in each fluid resistance substrate 120. A liquid outlet 36 is also connected to the common liquid chamber 3. Of the liquid in the common liquid chamber 3, the liquid that is not supplied to each pressure chamber 4 via the openings 4a in the fluid resistance substrate 120 is returned from the liquid outlet 36 to an external ink storage unit via an external pump or the like.

[0035] Next, the piezoelectric element 5, which is a characteristic feature of this embodiment, will be described. FIG. 8 is a schematic diagram showing an example of the piezoelectric element 5 in this embodiment. 8, the piezoelectric element 5 of this embodiment is composed of two piezoelectric elements 5A, 5B, each arranged in a circumferential portion around the nozzle communication opening 4b on the pressure chamber inner wall (nozzle plate 110) that communicates with the nozzle 2. The two piezoelectric elements 5A, 5B are arranged at positions offset from each other in the circumferential direction so as not to overlap each other in the circumferential direction. This configuration can be said to be a configuration in which, when viewed perpendicular to the nozzle surface, the annular piezoelectric element 5 arranged to surround the periphery of the nozzle 2 is divided into two in the circumferential direction.

[0036] The two piezoelectric elements 5A, 5B arranged for one nozzle 2 may be arranged so as to partially overlap each other in the circumferential direction. That is, there are no limitations on the arrangement, shape, size, etc. of the piezoelectric elements 5A, 5B, as long as they generate biased pressures with respect to the nozzle communication opening 4b in different regions of the pressure chamber 4 when a drive voltage is applied to each of them, as viewed from the perpendicular direction to the nozzle face. Therefore, for example, as shown in Figure 9(a), even if the two piezoelectric elements 5A, 5B are annular and arranged to surround the periphery of the nozzle 2 (two annular piezoelectric elements 5A, 5B arranged to form a double annulus), it is sufficient that they are configured to generate a deviation in piezoelectric displacement in the circumferential direction.

[0037] 9(b), three or more (four in FIG. 9(b)) piezoelectric elements 5A to 5D may be arranged for one nozzle 2. Note that the more piezoelectric elements arranged for one nozzle 2, the greater the degree of freedom in the ejection direction of the liquid ejected from the nozzle 2, as will be described later.

[0038] Next, control of the liquid ejection direction will be described. For simplicity, the following explanation will be given assuming a configuration in which two piezoelectric elements 5A and 5B are arranged for one nozzle 2, as shown in Figure 8, with the element on the left side of the figure being the left piezoelectric element 5A and the element on the right side of the figure being the right piezoelectric element 5B.

[0039] First, the case where liquid is ejected in a direction perpendicular to the nozzle surface (hereinafter referred to as "normal ejection") will be described. Figure 10(a) is an explanatory diagram showing the liquid ejection direction when performing normal ejection, Figure 10(b) is an explanatory diagram showing an example of the drive voltage applied to the left piezoelectric element 5A when performing normal ejection, and Figure 10(c) is an explanatory diagram showing an example of the drive voltage applied to the right piezoelectric element 5B when performing normal ejection.

[0040] In this embodiment, when normal ejection is performed, a drive voltage having the same drive waveform is applied to the two piezoelectric elements 5A and 5B, as shown in FIGS. 10(b) and 10(c). In this embodiment, the two piezoelectric elements 5A and 5B are configured to be axially symmetric with respect to the nozzle communication opening 4b. Therefore, when these piezoelectric elements 5A and 5B are driven by a drive voltage having the same drive waveform, a substantially uniform pressure is generated within the pressure chamber 4 that is axially symmetric with respect to the nozzle communication opening 4b, and a pressure fluctuation that is symmetric with respect to the nozzle communication opening 4b can be generated within the pressure chamber 4. As a result, similar to a conventional configuration in which one annular piezoelectric element is arranged for one nozzle 2, the liquid ejection direction S0 of the liquid I ejected from the nozzle 2 is perpendicular to the nozzle surface, as shown in FIG. 10(a).

[0041] Next, a case where liquid is ejected in a direction oblique to the vertical direction of the nozzle surface (hereinafter referred to as "oblique ejection") will be described. Figure 11(a) is an explanatory diagram showing the liquid ejection direction when obliquely ejecting liquid to the right in the figure relative to the perpendicular direction of the nozzle surface, Figure 11(b) is an explanatory diagram showing an example of the drive voltage applied to the left piezoelectric element 5A when obliquely ejecting liquid to the right in the figure relative to the perpendicular direction of the nozzle surface, and Figure 11(c) is an explanatory diagram showing an example of the drive voltage applied to the right piezoelectric element 5B when obliquely ejecting liquid to the right in the figure relative to the perpendicular direction of the nozzle surface.

[0042] When oblique ejection is performed to the right in the figure with respect to the vertical direction of the nozzle face, in this embodiment, as shown in Figure 11(b), a drive voltage having the drive waveform shown in the figure is applied to the left piezoelectric element 5A. This causes the vibration membrane 103 in the nozzle plate portion where the left piezoelectric element 5A is arranged to vibrate, causing pressure fluctuations in the region of the pressure chamber 4 facing the vibration membrane 103 in this portion. Meanwhile, at this time, as shown in Figure 11(c), no drive voltage is applied to the right piezoelectric element 5B. This causes the vibration membrane 103 in the nozzle plate portion where the right piezoelectric element 5B is arranged not to vibrate, so no pressure fluctuations due to the right piezoelectric element 5B occur in the region of the pressure chamber 4 facing the vibration membrane 103 in this portion; only the pressure fluctuations due to the left piezoelectric element 5A are transmitted. As a result, an asymmetric pressure is generated within the pressure chamber 4 relative to the nozzle connection opening 4b, and the liquid ejection direction S1 of the liquid I ejected from the nozzle 2 is diagonal to the right in the figure with respect to the direction S0 perpendicular to the nozzle surface, as shown in Figure 11(a).

[0043] FIG. 12(a) is a diagram showing pressure fluctuations inside the pressure chamber 4 when drive voltages having the same drive waveform are applied to the two piezoelectric elements 5A and 5B (in the case of normal ejection). FIG. 12(b) is a diagram showing pressure fluctuations inside the pressure chamber 4 when a drive voltage is applied only to the left piezoelectric element 5A and no drive voltage is applied to the right piezoelectric element 5B (in the case of oblique ejection). In Figures 12(a) and (b), the shade of color indicates the difference in pressure.

[0044] When a drive voltage having the same drive waveform is applied to the two piezoelectric elements 5A and 5B (in the case of normal ejection), as shown in Figure 12(a), it can be seen that a pressure fluctuation occurs symmetrically with respect to the nozzle-connecting opening 4b near the nozzle inside the pressure chamber 4. On the other hand, when a drive voltage is applied only to the left-side piezoelectric element 5A, it can be seen that a pressure fluctuation occurs asymmetrically with respect to the nozzle-connecting opening 4b near the nozzle inside the pressure chamber 4, as shown in Figure 12(b).

[0045] FIG. 13(a) is a diagram showing the results of numerical calculations of the liquid ejection direction S0 when drive voltages having the same drive waveform are applied to the two piezoelectric elements 5A and 5B (in the case of normal ejection). FIG. 13(b) is a diagram showing the results of numerical calculations of the liquid ejection direction S1 when a drive voltage is applied only to the left piezoelectric element 5A and no drive voltage is applied to the right piezoelectric element 5B (in the case of oblique ejection).

[0046] When a drive voltage having the same drive waveform is applied to the two piezoelectric elements 5A and 5B (in the case of normal ejection), the ejection direction S0 of the liquid I ejected from the nozzle 2 is perpendicular to the nozzle surface, as shown in Fig. 13(a). On the other hand, when a drive voltage is applied only to the left piezoelectric element 5A, the liquid ejection direction S1 of the liquid I ejected from the nozzle 2 is diagonal to the right in the figure with respect to the direction perpendicular to the nozzle surface, as shown in Fig. 13(b).

[0047] In this embodiment, by appropriately changing the waveform shape of the drive voltage applied to the two piezoelectric elements 5A and 5B (rising angle, falling angle of the drive waveform, voltage application time (width of the drive waveform), etc.), voltage value, timing of applying the drive voltage to each piezoelectric element 5A and 5B (shifting the timing between piezoelectric elements 5A and 5B), etc., it is possible to control the liquid ejection angle θ, the amount of liquid ejected (droplet size), the liquid ejection speed, etc.

[0048] For example, the steeper the rising angle of the drive waveform, the larger the liquid ejection angle θ. However, depending on the head structure, etc., the steeper the rising angle of the drive waveform, the smaller the liquid ejection angle θ may be. Alternatively, the liquid ejection angle θ may increase as the rising angle of the drive waveform increases up to a certain rising angle, but once the certain angle is exceeded, the liquid ejection angle θ may decrease.

[0049] Furthermore, for example, with regard to the width (pulse width) of the drive waveform, normally, the liquid ejection angle θ increases as the width of the drive waveform increases up to a certain width, but once the certain width is exceeded, the liquid ejection angle θ decreases.

[0050] Figures 14(a) and (b) respectively show the numerical calculation results of the liquid ejection angle θ when the drive voltage is applied only to the left piezoelectric element 5A (in the case of oblique ejection) and the voltage value of the drive voltage is changed. Note that Figure 14(a) shows the liquid ejection angle θ1 when the drive voltage applied only to the left piezoelectric element 5A is set to 340 V, and Figure 14(b) shows the liquid ejection angle θ2 when the drive voltage applied only to the left piezoelectric element 5A is set to 400 V. Comparing FIGS. 14(a) and (b), it is clear that the liquid ejection angle θ can be increased by increasing the voltage value of the drive voltage applied only to the left-side piezoelectric element 5A.

[0051] [Operation example 1] Next, an operation example (hereinafter, this operation example will be referred to as "operation example 1") of a liquid ejection device that utilizes control of the liquid ejection direction in the liquid ejection head of this embodiment will be described. Operation example 1 is an example of operation that suppresses image quality degradation such as white streaks and uneven color density caused by the occurrence of nozzles (non-ejecting nozzles) that are clogged with dust or dried liquid and are no longer able to eject liquid. Operation example 1 is non-ejecting nozzle supplementary control that compensates for the liquid ejected from the non-ejecting nozzle by obliquely ejecting liquid ejected from other nozzles.

[0052] FIG. 15 is an explanatory diagram showing a conventional general non-ejecting nozzle supplementary control. In conventional non-ejecting nozzle complementary control, liquid is ejected from the nozzle only in the direction perpendicular to the nozzle surface, and not in diagonal directions. Therefore, in conventional non-ejecting nozzle complementary control, as shown in Figure 15, a larger-sized droplet I1 (a larger amount of liquid) than the normal-sized droplet I0 (a normal amount of liquid) ejected from a normal nozzle 2b is ejected from a complementary nozzle 2a adjacent to the non-ejecting nozzle 2e.

[0053] However, with this type of non-ejecting nozzle complementary control, there is a large difference in size between the complementary droplets I1 ejected from the complementary nozzle 2a and the normal droplets I0 ejected from the normal nozzle 2b, and the effect of suppressing image quality degradation is insufficient. Furthermore, with this type of non-ejecting nozzle complement control, the landing position of the complementary droplet I1 on the recording material P is significantly different from the landing position of the non-ejecting nozzle 2e, and in this respect too, the effect of suppressing image quality degradation is insufficient.

[0054] FIG. 16 is an explanatory diagram showing an example of non-ejecting nozzle complement control in this operation example 1. In the non-ejecting nozzle complementary control of this operation example 1, as shown in Figure 16, a droplet I1 of approximately the same size as the normal-sized droplet I0 (normal liquid amount) ejected from the normal nozzle 2b is ejected obliquely from the complementary nozzle 2a adjacent to the non-ejecting nozzle 2e toward the landing position of the non-ejecting nozzle 2e.

[0055] According to the non-ejecting nozzle complementary control of this operation example 1, there is no difference in size between the complementary droplet I1 ejected from the complementary nozzle 2a and the normal droplet I0 ejected from the normal nozzle 2b. Moreover, according to the non-ejecting nozzle complementary control of this operation example 1, the landing position of the complementary droplet I1 on the recording material P coincides with the landing position of the non-ejecting nozzle 2e. Therefore, according to this operation example 1, a high effect of suppressing image quality degradation can be obtained.

[0056] Here, in the case of oblique ejection, the distance from the complementary nozzle 2a to the landing position on the recording material P is longer than in the case of normal ejection. Therefore, it is preferable that the liquid ejection speed when the complementary droplets I1 are obliquely ejected from the complementary nozzle 2a is faster than the liquid ejection speed when the complementary droplets I1 are normally ejected from the complementary nozzle 2a. This makes it possible to reduce the time difference between ejection and normal ejection until landing, eliminating the need to set exceptional timing as the ejection timing for oblique ejection.

[0057] Methods for increasing the liquid ejection speed during oblique ejection include, for example, increasing the voltage value of the applied drive voltage or changing the drive waveform. When the voltage value of the applied drive voltage is increased, the liquid ejection speed increases and the amount of liquid ejected (droplet size) also increases. In such cases, it is preferable to change the drive waveform of the drive voltage to suppress the increase in the amount of liquid ejected (droplet size) while ensuring an increase in the liquid ejection speed.

[0058] In the example of Fig. 16, a driven nozzle that performs normal ejection at that ejection timing is used as the complementary nozzle 2a, but it is preferable to use a non-driven nozzle that does not perform normal ejection at that ejection timing as the complementary nozzle 2a, as shown in Fig. 17. In particular, as shown in Fig. 9(b), if three or more (four in Fig. 9(b)) piezoelectric elements 5A to 5D are arranged for one nozzle 2, there is a high degree of freedom in the liquid ejection direction, so that it is possible to select a non-driven nozzle as the complementary nozzle 2a not only from the two adjacent nozzles located on both sides of the non-ejecting nozzle 2e, but also from the nine adjacent nozzles surrounding the non-ejecting nozzle 2e, as shown in Fig. 18.

[0059] Furthermore, when the driven nozzle performing normal ejection at that ejection timing is used as the complementary nozzle 2a, it may be obliquely ejected toward a position between the landing position of the complementary nozzle 2a during normal ejection and the landing position of the non-ejecting nozzle 2e, as shown in Figure 19. In this case, the size (liquid amount) of the droplet I2 ejected from the complementary nozzle 2a is made larger than the normal-sized droplet I0 (normal liquid amount) ejected from the normal nozzle 2b.

[0060] Even in the example of Figure 19, the difference between the size of the complementary droplet I2 and the size of the normal droplet I0 is small, and the deviation of the landing position of the complementary droplet I2 from the landing position of the non-ejecting nozzle 2e is small, compared to the conventional general non-ejecting nozzle complement control shown in Figure 15. Therefore, a high degree of suppression of image quality degradation can be achieved.

[0061] Furthermore, the nozzle used as the complementary nozzle 2a is not limited to the adjacent nozzle adjacent to the non-ejecting nozzle, but it is also possible to use the nozzle further adjacent to the adjacent nozzle.

[0062] FIG. 20 is an explanatory diagram showing a control block relating to non-ejecting nozzle complement control in this operation example 1. In this example, the liquid ejecting device is a head scanning type printing device that is an inkjet recording device serving as an image forming device.

[0063] In the non-ejecting nozzle complement control of this operation example 1, first, before printing an image with the printing apparatus, a test image is printed on the recording material P to perform a test and an inspection process is carried out to find non-ejecting nozzles. In the inspection process, the control unit 81 sends signals to the ejection control unit 82 and the head driving unit 83 based on predetermined test image data. As a result, the ejection control unit 82 applies a predetermined drive voltage to the piezoelectric elements 5A and 5B at a predetermined timing, causing liquid to be ejected from each nozzle 2 in accordance with the test image data. In addition, the head driving unit 83 drives the carriage on which the liquid ejection head 1 is mounted, and moves (scans) the liquid ejection head 1 in the scanning direction indicated by the arrow in the figure. Through these operations, a test image in accordance with the test image data is formed on the recording material P.

[0064] The test image formed on the recording material P is read by a detection unit 85, which is made up of a camera or the like provided inside or outside the printing device, and the presence of defective pixels Ge is checked based on the read image data. If a defective pixel Ge is found, the non-ejecting nozzle 2e is identified from the position of the defective pixel that was found, and information about the non-ejecting nozzle 2e is fed back to the control unit 81. The information about the non-ejecting nozzle 2e is stored and held in a memory unit 84.

[0065] By carrying out such an inspection process, when an image is printed in a subsequent print job and liquid is to be ejected from a nozzle stored as a non-ejecting nozzle 2e, the control unit 81 issues a complement instruction for that non-ejecting nozzle 2e to the ejection control unit 82. As a result, the ejection control unit 82 sets a nozzle selected in accordance with predetermined selection conditions from the nozzles positioned around that non-ejecting nozzle 2e as a complementary nozzle 2a, changes the drive voltages applied to the two piezoelectric elements 5A, 5B corresponding to that complementary nozzle 2a, and executes non-ejecting nozzle complementation control in which complementary droplets are obliquely ejected from the complementary nozzle 2a to complement the non-ejecting nozzle 2e.

[0066] Furthermore, instead of a test image, the inspection process may be performed using an image (user image) printed by a print job. That is, the image formed on the recording material P by the print job is read by the detection unit 85 inside the printing device, and the presence of defective pixels Ge is inspected based on the read image data. The inspection results are then immediately fed back to the control unit 81, and non-ejecting nozzle compensation control based on the inspection results is executed when the image is subsequently printed. This makes it possible to realize a system that compensates for non-ejecting nozzles while actually printing.

[0067] [Operation example 2] Next, an operation example (hereinafter, this operation example will be referred to as "operation example 2") of a liquid ejection device that utilizes control of the liquid ejection direction in the liquid ejection head of this embodiment will be described. Operation example 2 is an operation example for suppressing image quality degradation caused by the occurrence of defective nozzles that cause ejection deflection, in which the ejection direction of liquid deviates from the target direction (the perpendicular direction to the nozzle surface) due to individual differences in nozzle shape (such as manufacturing errors) or foreign matter adhering to the nozzle. Operation example 2 is ejection deflection correction control that corrects the ejection deflection by performing an oblique ejection operation so that the ejection direction of liquid ejected from such defective nozzles that cause ejection deflection approaches the target direction.

[0068] Fig. 21(a) is an explanatory diagram showing the ejection direction of a droplet I3 ejected from a faulty nozzle 2f when the ejection deflection correction control of Operation Example 2 is not performed. Fig. 21(b) is an explanatory diagram showing the ejection direction of a droplet I3 ejected from a faulty nozzle 2f when the ejection deflection correction control of Operation Example 2 is performed. The control block in this operation example 2 is the same as that in operation example 1 shown in FIG.

[0069] In the deflected ejection correction control of this operation example 2, first, before printing an image with the printing device, an inspection process is carried out in which a test image is printed on the recording material P to perform an inspection and find any defective nozzles causing deflected ejection. Then, the test image formed on the recording material P is read by a detection unit 85 consisting of a camera or the like provided inside or outside the printing device, and a defective nozzle 2f whose landing position is deviated is identified based on the read image data, and information about the defective nozzle 2f is fed back to the control unit 81. The information about the defective nozzle 2f is stored and held in a memory unit 84.

[0070] The detection unit for finding faulty nozzles 2f with misaligned landing positions may, for example, directly observe the ejection state of the liquid ejected from the nozzles with a camera and detect faulty nozzles 2f with deflected ejection.

[0071] By carrying out this inspection process, when an image is printed by a subsequent print job and liquid is ejected from the nozzle stored as a faulty nozzle 2f, the control unit 81 issues an instruction to correct the deflection of the ejection for that faulty nozzle 2f to the ejection control unit 82. As a result, the ejection control unit 82 changes the drive voltages applied to the two piezoelectric elements 5A, 5B corresponding to that faulty nozzle 2f, and executes ejection deflection correction control to correct the deflection of the ejection so that the liquid ejection direction from that faulty nozzle 2f is oriented in the target direction (perpendicular to the nozzle surface) as shown in Fig. 21(b).

[0072] According to this second operational example, it is possible to correct not only the ejection deflection detected before the shipping of the printing device, but also the unexpected ejection deflection that occurs after the shipping of the printing device.

[0073] Next, an example of a liquid ejection device according to the present invention will be described with reference to FIGS. FIG. 22 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. 23 is an explanatory plan view of an example of a head unit of a printing device according to this embodiment.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] Next, another example of a printing apparatus as a liquid ejecting apparatus according to the present invention will be described with reference to FIGS. FIG. 24 is an explanatory plan view of the main parts of the printing apparatus of this example. FIG. 25 is an explanatory side view of the main part of the printing apparatus of this example.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 26 is a plan view illustrating the main parts of the liquid discharge unit of this example.

[0085] 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.

[0086] 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.

[0087] Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 27 is an explanatory front view of the liquid discharge unit of this example.

[0088] 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 .

[0089] 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.

[0090] 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.

[0091] The liquid to be ejected may be a metallic material such as solder or a material that is fixed at room temperature, such as wax ink, which is heated and melted before being ejected from the nozzle. Alternatively, the liquid to be ejected may be a liquid that is highly viscous at room temperature, such as UV ink, which is heated and reduced in viscosity before being ejected from the nozzle. In this case, by providing a heating means such as a heater on the frame portion 140 or the pressure chamber substrate 100, the material in the pressure chamber 4 can be melted or reduced in viscosity, allowing for smooth ejection of the liquid from the nozzle. In this case, aluminum nitride (AlN) containing at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, and boron is preferably used as the electrostrictive material for the piezoelectric element. Specifically, a portion of the aluminum in the aluminum nitride is replaced with at least one of the above materials. This allows the aluminum nitride to contain at least one of the above materials. By replacing a portion of the aluminum in the aluminum nitride as a piezoelectric material with at least one of the above materials, the piezoelectric performance can be improved. The electrostrictive material of the piezoelectric body is not limited to aluminum nitride, but may be any electrostrictive material having high heat resistance and whose displacement does not change even in a high temperature environment.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] Furthermore, there is a liquid ejection unit in which the liquid ejection head and the carriage are integrated.

[0096] 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.

[0097] 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.

[0098] In some liquid ejection units, a tube is connected to a liquid ejection head equipped with a head tank or flow path components, integrating the liquid ejection head with a supply mechanism. Liquid is supplied from a liquid storage source to the liquid ejection head via this tube.

[0099] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0100] 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.

[0101] "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.

[0102] 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.

[0103] 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).

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] In the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

[0110] The above description is merely an example, and each of the following aspects provides unique effects. [First aspect] The first aspect is a liquid ejection head 1 comprising a nozzle 2 that ejects liquid, a pressure chamber 4 that communicates with the nozzle, and an actuator (e.g., a piezoelectric element 5) that is provided on a nozzle forming wall of the pressure chamber (e.g., a nozzle plate 110), wherein the actuator is characterized by being composed of a plurality of actuator elements (e.g., piezoelectric elements 5A to 5D) that generate biased pressure against a nozzle communication opening 4b on the nozzle forming wall that communicates with the nozzle. In this embodiment, the actuator provided in the nozzle forming wall of one pressure chamber corresponding to one nozzle is composed of multiple actuator elements. These actuator elements can generate biased pressures in different regions within the single pressure chamber relative to the nozzle communication opening 4b of the nozzle forming wall. Liquid pressurized by such biased pressure is not ejected from the nozzle in a straight line perpendicular to the nozzle surface, but is ejected in a direction oblique to the direction perpendicular to the nozzle surface. The direction of liquid ejection from the nozzle can be controlled by appropriately changing the drive voltages applied to the multiple actuator elements. Therefore, according to this embodiment, it is possible to control the direction of liquid ejection from the nozzle in a configuration in which one pressure chamber is provided for one nozzle. In a configuration in which multiple actuator elements are arranged on the side facing the nozzle forming wall within a pressure chamber, even if the pressure generated by each actuator element is uneven, the pressure will be equalized due to mutual interference as it propagates through the pressure chamber toward the nozzle forming wall. As a result, the pressure unevenness is small near the nozzle communication opening 4b in the nozzle forming wall, making it difficult to eject liquid from the nozzle in a direction oblique to the direction perpendicular to the nozzle surface, and also making it difficult to direct the liquid ejection direction at a large oblique angle. It is believed that conventional devices use separate pressure chambers for each actuator element to prevent mutual interference between the pressures generated by the multiple actuator elements. In this embodiment, as described above, a plurality of actuator elements are provided on the nozzle forming wall of the pressure chamber. Therefore, the biased pressure generated by these actuator elements can be generated near the nozzle communication opening 4b of the nozzle forming wall. This makes it easy to eject liquid from the nozzle in a direction oblique to the direction perpendicular to the nozzle surface, and also makes it easy to direct the liquid ejection direction at a large oblique angle.

[0111] [Second mode] The second aspect is a liquid ejection head 1 comprising a nozzle 2 that ejects liquid, a pressure chamber 4 that communicates with the nozzle, and an actuator (e.g., a piezoelectric element 5) that is provided on a nozzle forming wall of the pressure chamber (e.g., a nozzle plate 110), wherein the actuator is characterized by being composed of a plurality of actuator elements (e.g., piezoelectric elements 5A to 5D) that can generate uniform pressure and biased pressure to a nozzle communication opening 4b on the nozzle forming wall that communicates with the nozzle. According to this aspect, by appropriately changing the drive voltage applied to the multiple actuator elements, it is possible to eject ink from the nozzle in a direction oblique to the direction perpendicular to the nozzle surface, or to eject ink from the nozzle in a straight line perpendicular to the nozzle surface.

[0112] [Third aspect] The third aspect is characterized in that in the first or second aspect, the plurality of actuator elements include two or more actuator elements that are arranged in a circumferential portion around the nozzle communication opening 4b and are arranged circumferentially offset from each other. According to this, as the two or more actuator elements, for example, actuator elements that have a uniform structure in the circumferential direction and are easy to fabricate can be used.

[0113] [Fourth aspect] A fourth aspect is the third aspect, characterized in that the two or more actuator elements are arranged so as not to overlap with each other in the circumferential direction. This allows the two or more actuator elements to be disposed at equal distances from the nozzle communication opening 4b, thereby realizing a smaller actuator.

[0114] [Fifth mode] A fifth aspect is characterized in that in any one of the first to fourth aspects, the actuator element is a piezoelectric element. This makes it possible to eject a wide variety of liquids. For example, in the case of a piezoelectric element, compared to other actuator elements such as a thermal element, it is possible to use liquids with lower heat resistance.

[0115] [Sixth aspect] The sixth aspect is a device for ejecting liquid, characterized in that it comprises a liquid ejection head according to any one of the first to fifth aspects, and a drive voltage control unit (e.g., ejection control unit 82) that individually controls the drive voltages applied to the plurality of actuator elements in the liquid ejection head. According to this aspect, in a configuration in which one pressure chamber is provided for one nozzle, it becomes possible to control the direction in which liquid is ejected from the nozzle.

[0116] [Seventh aspect] A seventh aspect is the sixth aspect, characterized in that the drive voltage control unit controls the ejection direction of liquid ejected from nozzles corresponding to the plurality of actuator elements by changing the drive voltage applied to the plurality of actuator elements. According to this aspect, it is possible to easily control the ejection direction of the liquid ejected from the nozzle.

[0117] [Eighth aspect] The eighth aspect is a liquid ejection device according to the seventh aspect, characterized in that the drive voltage control unit controls so as not to apply a drive voltage to at least one actuator element (e.g., the right-side piezoelectric element 5B) when controlling in a predetermined ejection direction. This makes it possible to achieve power saving.

[0118] [Ninth aspect] A ninth aspect is a liquid ejection device according to the seventh or eighth aspect, characterized in that when controlling the ejection direction of liquid ejected from the nozzle, the drive voltage control unit controls at least one of the ejection amount and ejection speed of the liquid ejected from the nozzle by changing the drive voltage applied to the plurality of actuator elements corresponding to the nozzle. This makes it possible to control the amount and speed of liquid ejected from the nozzles, the direction of which the liquid is ejected being controlled.

[0119] [Tenth aspect] A tenth aspect is characterized in that, in any of the seventh to ninth aspects, the liquid ejection head has a plurality of nozzles, pressure chambers, and actuators, and the drive voltage control unit controls the ejection direction of liquid ejected from another nozzle (for example, a complementary nozzle 2a) among the plurality of nozzles in order to compensate for the liquid ejected from a non-ejecting nozzle 2e among the plurality of nozzles that cannot eject liquid with liquid ejected from the other nozzle. According to this aspect, the deviation of the landing position of the complementary droplets from the landing position of the non-ejecting nozzle 2e is smaller than when non-ejecting nozzle complementary control is performed with a conventional configuration that cannot control the liquid ejection direction. Therefore, when compensating for image quality degradation caused by the non-ejecting nozzle 2e, a high effect of suppressing image quality degradation can be achieved.

[0120] [Eleventh aspect] The eleventh aspect is characterized in that, in the tenth aspect, when the drive voltage control unit compensates for the amount of liquid ejected from the non-ejecting nozzle by controlling the ejection direction of the liquid ejected from the other nozzles, it controls the other nozzles to eject an amount of liquid equal to the amount of liquid ejected from the non-ejecting nozzle. According to this aspect, when compensating for the deterioration in image quality caused by the non-ejecting nozzle 2e, it is possible to obtain an even greater effect in suppressing the deterioration in image quality.

[0121] [12th aspect] The twelfth aspect is characterized in that, in any of the seventh to ninth aspects, the drive voltage control unit controls the ejection direction of liquid ejected from a defective nozzle 2f whose ejection direction deviates from a target direction (e.g., a direction perpendicular to the nozzle surface) so that the ejection direction of liquid ejected from the defective nozzle approaches the target direction. According to this aspect, a defective nozzle, the liquid ejection direction of which deviates from the target direction, can be used as a normal nozzle.

[0122] [13th aspect] A thirteenth aspect is a method for controlling a device for ejecting liquid that is equipped with a liquid ejection head according to any one of the first to fifth aspects, characterized in that the ejection direction of liquid ejected from nozzles corresponding to the plurality of actuator elements is controlled by changing the drive voltage applied to the plurality of actuator elements. According to this aspect, in a configuration in which one pressure chamber is provided for one nozzle, it becomes possible to control the direction in which liquid is ejected from the nozzle. [Explanation of symbols]

[0123] 1: Liquid ejection head 2: Nozzle 2a: Complementary nozzle 2e: Non-ejecting nozzle 2f: Defective nozzle 3: Common liquid chamber 4: Pressure chamber 4a: Opening 5, 5A to 5D: Piezoelectric elements 11:Protective film 33:Liquid supply port 36:Liquid outlet 40: Pressure chamber array 51:First electrode 52: Piezoelectric film 53:Second electrode 55: Electrical connection pad 81: Control unit 82: Discharge control section 83: Head drive unit 84: Storage section 85:Detection unit 100: Pressure chamber substrate 100A, 100B: Head module 101: Drive circuit 102:Wiring section 103: Vibration membrane 110: Nozzle plate 111: Nozzle forming section 112: Liquid repellent film 120: Fluid resistance board 140: Frame section 151: First electrode layer 152: Piezoelectric layer 153:Second electrode layer 440: Liquid dispensing unit 500:Printing device 550: Head unit Ge: Defective pixel P: Recording material S:Liquid discharge direction θ:Liquid discharge angle [Prior art documents] [Patent documents]

[0124] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-358701

Claims

1. a nozzle for discharging a liquid; a pressure chamber communicating with the nozzle; an actuator provided on a nozzle forming wall of the pressure chamber, The liquid ejection head is characterized in that the actuator is composed of a plurality of actuator elements that generate biased pressure against nozzle communication openings on the nozzle forming wall that communicate with the nozzles.

2. a nozzle for discharging a liquid; a pressure chamber communicating with the nozzle; an actuator provided on a nozzle forming wall of the pressure chamber, The liquid ejection head is characterized in that the actuator is composed of a plurality of actuator elements capable of generating uniform pressure and biased pressure to the nozzle communication openings on the nozzle forming wall that communicate with the nozzles.

3. 3. The liquid ejection head according to claim 1, The liquid ejection head is characterized in that the plurality of actuator elements include two or more actuator elements that are arranged in a circumferential portion around the nozzle communication opening and are arranged circumferentially shifted from each other.

4. 4. The liquid ejection head according to claim 3, The liquid ejection head is characterized in that the two or more actuator elements are arranged so as not to overlap with each other in the circumferential direction.

5. 3. The liquid ejection head according to claim 1, The liquid ejection head is characterized in that the actuator element is a piezoelectric element.

6. The liquid ejection head according to claim 1 or 2; a drive voltage control unit that individually controls drive voltages applied to the plurality of actuator elements in the liquid ejection head.

7. 7. The liquid ejection device according to claim 6, a drive voltage control unit that controls the ejection direction of liquid ejected from nozzles corresponding to the plurality of actuator elements by changing the drive voltage applied to the plurality of actuator elements;

8. The liquid ejection device according to claim 7, The liquid ejection device, wherein the drive voltage control unit controls so that a drive voltage is not applied to at least one actuator element when controlling the ejection in a predetermined ejection direction.

9. The liquid ejection device according to claim 7, a drive voltage control unit that, when controlling the ejection direction of the liquid ejected from the nozzle, controls at least one of the ejection amount and the ejection speed of the liquid ejected from the nozzle by changing the drive voltage applied to the plurality of actuator elements corresponding to the nozzle.

10. The liquid ejection device according to claim 7, the liquid ejection head includes a plurality of nozzles, a plurality of pressure chambers, and a plurality of actuators; A liquid ejection device characterized in that the drive voltage control unit controls the ejection direction of liquid ejected from other nozzles among the plurality of nozzles in order to compensate for the amount of liquid ejected from non-ejecting nozzles among the plurality of nozzles that are unable to eject liquid with liquid ejected from the other nozzles.

11. The liquid ejection device according to claim 10, A liquid ejection device characterized in that, when compensating for the amount of liquid ejected from the non-ejecting nozzle by controlling the ejection direction of the liquid ejected from the other nozzles, the drive voltage control unit controls the ejection of an amount of liquid from the other nozzles equal to the amount of liquid ejected from the non-ejecting nozzle.

12. The liquid ejection device according to claim 7, The liquid ejection device is characterized in that the drive voltage control unit controls the ejection direction of liquid ejected from a defective nozzle, whose ejection direction deviates from the target direction, so that the ejection direction of liquid ejected from the defective nozzle approaches the target direction.

13. A method for controlling a liquid ejection device including the liquid ejection head according to claim 1 or 2, comprising: A method for controlling a liquid ejecting device, comprising controlling an ejection direction of liquid ejected from nozzles corresponding to the plurality of actuator elements by changing a drive voltage applied to the plurality of actuator elements.

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