Liquid dispensing head, liquid dispensing unit, and device for dispensing liquid

Abstract

To provide a liquid discharge head that can reduce crosstalk, a liquid discharge unit and a liquid discharge device.SOLUTION: A liquid discharge head supplies liquid from a common liquid chamber 3 to pressurization liquid chambers 4 communicated with a plurality of nozzles 2 respectively, and makes the nozzles 2 discharge liquid in the pressurization liquid chambers by driving piezoelectric elements which are electromechanical conversion elements arranged at the nozzle side with respect to the pressurization liquid chambers 4. Further, openings through which liquid is supplied from the common liquid chamber 3 are formed at the opposite side of the nozzle side of the pressurization liquid chambers 4, where the cross sectional areas at the side of the openings of the pressurization liquid chambers 4 gradually increase as going toward the common liquid chamber.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid ejection head, a liquid ejection unit, and an apparatus for ejecting a liquid.

Background Art

[0002] There is known a liquid ejection head that supplies liquid from a common liquid chamber to pressure liquid chambers respectively communicating with a plurality of nozzles, drives an electromechanical conversion element disposed on the nozzle side with respect to the pressure liquid chambers, and ejects the liquid in the pressure liquid chambers from the front nozzles.

[0003] Patent Document 1 describes, as the liquid ejection head, one in which the cross-sectional area in the cross-section of the pressure liquid chamber perpendicular to the liquid ejection direction is the same in the liquid ejection direction.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there has been a possibility that so-called crosstalk occurs in which pressure fluctuations generated in the pressure liquid chamber propagate to the common liquid chamber and affect the ejection of the liquid in another pressure liquid chamber.

Means for Solving the Problems

[0005] In order to solve the above problems, the present invention supplies liquid from a common liquid chamber to pressure liquid chambers respectively communicating with a plurality of nozzles, drives an electromechanical conversion element disposed on the nozzle side with respect to the pressure liquid chambers, and in a liquid ejection head that ejects the liquid in the pressure liquid chambers from the nozzles, on the side opposite to the nozzle side of each pressure liquid chamber, has an opening through which the liquid is supplied from the common liquid chamber, and the cross-sectional area on the opening side of each pressure liquid chamber increases as it goes toward the common liquid chamber. The cross-sectional area of ​​the nozzle-side region of each pressurized liquid chamber is constant, compared to the region where the cross-sectional area increases towards the common liquid chamber on the opening side. It is characterized by the above.

Effects of the Invention

[0006] According to the present invention, crosstalk can be reduced. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic cross-sectional view showing the nozzle vibration type liquid discharge head in this embodiment. [Figure 2] A schematic perspective view showing the liquid dispensing head. [Figure 3] Enlarged cross-sectional view of section X in Figure 1. [Figure 4] A diagram illustrating the structure of the pressurized liquid chamber in this embodiment. [Figure 5] A diagram illustrating a modified version of the pressurized liquid chamber. [Figure 6] A diagram illustrating a modified side wall of the common liquid chamber. [Figure 7] A diagram illustrating a preferred example of the connection between the ceiling and side walls of a common liquid chamber. [Figure 8] A schematic diagram illustrating the printing apparatus in this embodiment. [Figure 9] A plan view diagram of an example of a head unit of the printing apparatus. [Figure 10] Plan view diagram illustrating the main components of another printing device. [Figure 11] Side view of the main components of the printing apparatus in this example. [Figure 12] Plan view illustrating the main components of the liquid dispensing unit in this example. [Figure 13] Front view diagram of the liquid dispensing unit in this example. [Modes for carrying out the invention]

[0008] The following describes one embodiment in which the present invention is applied to a liquid dispensing head provided in a device for dispensing liquid. It should be noted that the present invention is not limited to the embodiments shown below, and can be modified, added, altered, or deleted to the extent that a person skilled in the art can conceive of it. Any embodiment that achieves the function and effect of the present invention is included within the scope of the present invention.

[0009] The liquid discharge head in this embodiment is a nozzle vibration type liquid discharge head that discharges liquid from the nozzle by varying the pressure in the pressurized liquid chamber using an actuator unit having a nozzle. The nozzle vibration type has the advantage of being able to eject droplets with less force compared to a general unimorph type piezo head (which discharges liquid by vibrating a surface opposite to a surface having a communication port that communicates with the nozzle in the pressurized liquid chamber), and can be made more power-efficient and efficient in the actuator. In addition, since the volume of the pressurized liquid chamber can be reduced with the nozzle vibration type, it is possible to make the head smaller and increase the density of the nozzle.

[0010] Figures 1 to 3 schematically show the nozzle vibration type liquid discharge head in this embodiment. Figure 1 is a cross-sectional view, Figure 2 is a perspective view, and Figure 3 is an enlarged view of the area marked X in Figure 1. The liquid discharge head 1 includes an actuator section 110, a vibrating diaphragm 103, a flow path substrate 100, and a frame member 120.

[0011] The actuator section 110 is thin-film in shape and has a plurality of nozzles 2 for discharging liquid, and a piezoelectric element 5 as an annular electromechanical conversion element arranged around the nozzles 2. The flow channel substrate 100 has a plurality of pressurized liquid chambers (also called individual liquid chambers) 4, each communicating with a plurality of nozzles 2. The frame member 120 has a common liquid chamber 3 that is connected to the plurality of pressurized liquid chambers 4. Electrical connection pads 6 are provided at both ends of the liquid dispensing head 1 for connecting to external electrical components such as a power supply.

[0012] As shown in Figure 3, the flow channel substrate 100 is a substrate made of SOI (Silicon on Insulator) or SI, and has multiple pressurized liquid chambers 4 formed within it. Alternatively, an SOI substrate may be used as the flow channel substrate 100, and a drive circuit and wiring section may be provided within the substrate. The vibrating membrane 103 is formed on the flow channel substrate 100 and forms the lower surface, which is part of the wall surface of the pressurized liquid chamber 4.

[0013] The actuator unit 110 has a nozzle forming part (film) 111 in which a plurality of nozzles 2 are formed and which covers the piezoelectric element 5. A liquid repellent film may be formed on the nozzle surface of this nozzle forming part 111. By forming a liquid repellent film on the nozzle surface, adhesion of liquid to the nozzle surface can be suppressed, and it can be suppressed that the liquid discharged from the nozzle 2 is affected by the liquid adhering to the nozzle surface. When the solvent of the liquid is aqueous, perfluorodecyltrichlorosilane or perfluorooctytrichlorosilane can be used as the material of the liquid repellent film.

[0014] The piezoelectric element 5 of the actuator unit 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.

[0015] The first insulating film 8a is formed so as to cover the piezoelectric element 5 and the vibration film 103, and has a hole-shaped first contact 7a for electrically connecting to the first electrode 51 and a hole-shaped second contact 7b for electrically connecting to the second electrode 53. On this first insulating film 8a, a first lead-out wiring 9a as a wiring electrically connected to the first electrode 51 by the first contact 7a and a second lead-out wiring 9b electrically connected to the second electrode 53 by the second contact 7b are formed.

[0016] The first lead-out wiring 9a extends to the pad opening 10 on one end (the left end in FIG. 1) side of the liquid discharge head 1, and the portion of the pad opening 10 of the first lead-out wiring 9a serves as an electrical connection pad 6 for connecting to electrical components such as an external power source. The second lead-out wiring 9b extends to the pad opening on the other end (the right end in FIG. 1) side of the liquid discharge head 1, and the portion of the pad opening 10 of the second lead-out wiring 9b serves as an electrical connection pad 6 for connecting to electrical components such as an external power source.

[0017] The first lead wire 9a and the second lead wire 9b are covered by the second insulating film 8b. The second insulating film 8b also covers the piezoelectric element 5 and has the function of protecting the piezoelectric element 5 by preventing moisture that has entered the nozzle forming part 111 made of resin from entering the piezoelectric element 5.

[0018] Furthermore, if the inner surface of the pressurized liquid chamber and nozzle is eroded by the liquid, a liquid-resistant protective film may be provided on the inner surface of the pressurized liquid chamber and nozzle. Examples of protective films include metal oxides that form a passive body. Examples of metals for the metal oxide include tantalum (Ta), niobium (Nb), titanium (Ti), zirconium (Zr), hafnium (Hr), and tungsten (W), which have high compatibility with oxidation states. Zr and Hr, which have valencies similar to SiO2, or Ta, which have valencies around them, are particularly desirable.

[0019] Furthermore, it is preferable that the protective film is hydrophilic. The hydrophilic nature of the protective film allows the liquid to spread more easily to the inner surface of the pressurized liquid chamber 4 and nozzle 2 during filling. As a result, the liquid filling efficiency can be improved. If the solvent for the liquid is aqueous, a mixture of metal oxide and silicon dioxide (SiO2) at the molecular level can be used. Hydrophilicity can be imparted to the protective film by substituting the oxygen atoms in the SiO2 on the surface of the protective film to create hydrophilic OH groups.

[0020] Next, the distinctive features of this embodiment will be described. As shown in Figure 1, the pressurized liquid chamber 4 has a circular hole shape with an opening on the common liquid chamber 3 side, and the liquid in the common liquid chamber 3 is supplied to the pressurized liquid chamber 4 through this opening. However, there was a risk that pressure fluctuations in the pressurized liquid chamber 4 that occur when liquid is discharged from the nozzle 2 would propagate to the common liquid chamber 3 through the opening, and that these pressure fluctuations propagated to the common liquid chamber 3 would propagate to another pressurized liquid chamber, potentially causing so-called crosstalk that would affect the discharge of liquid in that chamber.

[0021] Therefore, in this embodiment, as shown in Figure 4, the tip 41 of the partition wall 4a separating adjacent pressurized liquid chambers 4 has a tapered cross-sectional shape, and the opening side of the pressurized liquid chamber 4 has a shape that widens in diameter. As a result, the cross-sectional area of ​​the opening side of the pressurized liquid chamber, cut in a direction perpendicular to the liquid discharge direction, increases as it approaches the common liquid chamber 3. As a result, the pressure in the pressurized liquid chamber 4 is rapidly dispersed at the opening side of the pressurized liquid chamber 4, and the pressure fluctuations in the pressurized liquid chamber 4 are reduced at the opening side of the pressurized liquid chamber 4 and propagated to the common liquid chamber 3. This reduces the influence of pressure fluctuations propagated from the common liquid chamber 3 to another pressurized liquid chamber 4 on liquid discharge. As a result, crosstalk can be suppressed.

[0022] Furthermore, in this embodiment, as shown in Figure 4, the tip of the partition wall 4a has a tapered shape, while the thickness of the rest of the partition wall 4a remains constant, and the cross-sectional area of ​​the pressurized liquid chamber 4 is constant except on the opening side. Compared to the case where the entire partition wall 4a has a shape in which the thickness gradually decreases towards the tip, the following advantages can be obtained: namely, the thickness of the partition wall 4a on the nozzle side can be suppressed, the distance between nozzles can be suppressed, and the nozzle density can be increased. In addition, the pressure in the pressurized liquid chamber 4 is rapidly dispersed on the opening side of the pressurized liquid chamber 4, which has the advantage of reducing pressure fluctuations propagated to the common liquid chamber 3.

[0023] Furthermore, by making the opening side of the pressurized liquid chamber 4 wider, air in the pressurized liquid chamber 4 can more easily escape into the common liquid chamber when the liquid is filled, thereby improving the liquid-filling efficiency of the pressurized liquid chamber 4.

[0024] In a typical unimorph-type piezo head (which discharges liquid by vibrating a surface opposite to a surface having a communication port that communicates with the nozzle in the pressurized liquid chamber), unlike the nozzle vibration method, the component having the nozzle (nozzle plate) can be made less prone to vibration, and the length of the nozzle can be increased (the thickness of the nozzle plate can be increased). Therefore, the meniscus of the nozzle is not destroyed by minor impacts. In contrast, in the nozzle vibration method, the component having the nozzle (actuator part 110 in this embodiment) is made of a thin film and is easily vibrated, and the length of the nozzle is also short, so the meniscus of the nozzle is easily destroyed by impact, and the meniscus is easily moved into the pressurized liquid chamber 4.

[0025] To move the meniscus, which has moved to the pressurized liquid chamber 4, back to the nozzle side, a force exceeding the negative pressure acting on the liquid is required. Therefore, it is necessary to perform a predetermined meniscus recovery operation by sucking liquid from the nozzle 2 or pressurizing and filling the liquid discharge head with liquid, thereby reforming the meniscus on the nozzle 2.

[0026] As mentioned above, in the nozzle vibration method, the nozzle meniscus is easily damaged, so the meniscus of nozzle 2 is frequently damaged, and each time the recovery operation described above must be performed. As a result, the device is often downtimed and ink is wasted, leading to significant user dissatisfaction. In addition, in the nozzle vibration method, the vibrating membrane 103 is a thin film, and there is a risk that cracks may occur in the vibrating membrane 103 during the recovery operation described above. Thus, in the nozzle vibration method, the nozzle meniscus is prone to being destroyed, so it is preferable to configure the nozzle so that the meniscus of nozzle 2 can recover naturally even if it is destroyed.

[0027] Figure 5 is a schematic diagram showing the pressurized liquid chamber 4 of the modified example 1. In the modified example 1 shown in Figure 5, the nozzle side 42 of the partition wall 4a has a cross-sectional shape that widens towards the nozzle, so that the cross-sectional area of ​​the pressurized liquid chamber 4 on the nozzle side gradually decreases towards the nozzle. Note that the nozzle side 42 of the partition wall 4a refers to the position on the nozzle side of the center of the partition wall 4a in the liquid discharge direction. By gradually reducing the cross-sectional area of ​​the pressurized liquid chamber 4 on the nozzle side toward the nozzle in this way, the nozzle meniscus can be naturally restored by the following action.

[0028] In other words, surface tension acts on the surface of the liquid that constitutes the liquid meniscus (the interface with the gas). This surface tension is a contractile force that tries to reduce the size of the interface. Therefore, as in the modified example, by making the cross-sectional area of ​​the pressurized liquid chamber 4 on the nozzle side gradually decrease as it approaches the nozzle 2, the interface becomes smaller on the nozzle side. Consequently, the meniscus in the pressurized liquid chamber moves towards the nozzle due to the surface tension of the liquid. Thus, even if the nozzle meniscus is destroyed due to an impact on the liquid discharge head or the like, and the meniscus moves into the pressurized liquid chamber, the meniscus will naturally move towards the nozzle due to the surface tension of the liquid. When a part of the meniscus reaches the surface of the pressurized liquid chamber 4 that has a communication port that connects to the nozzle 2, the liquid wets and spreads across this surface, and eventually the pressurized liquid chamber 4 is filled with liquid, allowing the nozzle meniscus to recover naturally.

[0029] Thus, in Modification 1, the nozzle meniscus can recover naturally, eliminating the need for meniscus recovery operations such as suctioning liquid from nozzle 2 or pressurizing and filling the liquid into the liquid discharge head when the meniscus of nozzle 2 is damaged. This reduces downtime for the device and prevents wasted ink consumption. Furthermore, by suppressing the occurrence of the above-mentioned meniscus recovery operation, it is possible to suppress the occurrence of cracks in the vibrating membrane 103, which is a thin film in the nozzle vibration method.

[0030] Furthermore, in Modification 1, the nozzle-side surface of the partition wall 4a becomes an inclined surface with respect to the liquid discharge direction, and the angle between the partition wall 4a and the vibrating membrane 103 becomes obtuse. As a result, compared to the case where the angle is 90° or less, the liquid flow during liquid filling is less likely to be obstructed, and the formation of air bubbles at the corner between the partition wall 4a and the vibrating membrane 103 can be suppressed, thereby improving the liquid filling performance. This allows for good liquid filling without actively expelling air from the pressurized liquid chamber 4 through the nozzle 2 by pressurizing the pressurized liquid chamber 4 with a pump or by covering the nozzle 2 with a suction cap and filling while sucking liquid from the nozzle 2. In the nozzle vibration method, the vibrating membrane 103 is a thin film, and there is a risk of cracks occurring in the vibrating membrane 103 if filling is performed while pressurizing or suction is applied. However, in Modification 1, liquid filling can be performed without pressurizing or suction, thus suppressing the occurrence of cracks in the vibrating membrane 103.

[0031] Furthermore, in this modified example 1, it is preferable to make the inner surfaces of the pressurized liquid chamber 4 and the nozzle 2 hydrophilic by providing a surface layer or performing a surface modification treatment on the inner circumference of the pressurized liquid chamber 4 and the nozzle 2. By making the inner surfaces of the pressurized liquid chamber 4 and the nozzle 2 hydrophilic, the liquid can be more easily wetted and spread across the inner surfaces of the pressurized liquid chamber 4 and the nozzle. This makes it even easier for the meniscus in the pressurized liquid chamber to move towards the nozzle due to surface tension. In addition, when a part of the meniscus comes into contact with the part of the vibrating membrane 103 that constitutes the wall surface of the pressurized liquid chamber 4 (the lower surface of the pressurized liquid chamber 4), the liquid can be more easily wetted and spread across the surface of the vibrating membrane 103. This allows the nozzle meniscus to recover naturally and effectively.

[0032] In this modified example 1, the cross-sectional area between the opening side and the nozzle side of the pressurized liquid chamber 4 is constant, and the thickness between the opening side (tip 41) and the nozzle side 42 of the partition wall 4a is constant. Therefore, it is possible to suppress the thickness of the nozzle side 42 of the partition wall 4a from increasing, and to suppress the widening of the distance between nozzles. In addition, the pressure in the pressurized liquid chamber 4 can be rapidly dispersed at the opening side of the pressurized liquid chamber 4, thereby enhancing the effect of reducing pressure fluctuations propagated to the common liquid chamber 3.

[0033] Furthermore, it is possible to suppress the increase in the thickness of the partition wall 4a on the nozzle side, thereby increasing the density of the nozzle. In addition, while suppressing the increase in the thickness of the partition wall 4a on the nozzle side, the angle between the partition wall 4a and the vibrating membrane 103 can be increased, suppressing the narrowing of the vibrable area of ​​the vibrating membrane 103, thereby suppressing a decrease in discharge efficiency and improving the liquid filling performance.

[0034] Furthermore, when the nozzle meniscus is destroyed, the piezoelectric element 5 may be driven to prevent liquid from being discharged from the nozzle. For example, the piezoelectric element 5 may be driven with an output of 50% or less, or at a slower driving speed, compared to when liquid is being discharged. This allows the air in the pressurized liquid chamber 4 to be discharged from the nozzle, and the meniscus due to surface tension can be restored. In particular, in the nozzle vibration method, the pressure on the air layer side (nozzle side) when the meniscus moves into the pressurized liquid chamber 4 can be fluctuated by driving the piezoelectric element 5, allowing air to be effectively discharged from the nozzle. This makes it possible to effectively discharge air from the nozzle with weak vibrations of the piezoelectric element that do not cause liquid to be discharged from the nozzle. Furthermore, depending on the drive waveform, the piezoelectric element 5 can be driven so that the angle between the partition wall 4a and the vibrating membrane 103 becomes obtuse, allowing for smoother air discharge from the nozzle. Note that the drive control of the piezoelectric element 5 when the nozzle meniscus is destroyed can be used with or without the configuration of Modification 1 (a configuration in which the nozzle side 42 of the partition wall 4a has a cross-sectional shape that widens towards the nozzle).

[0035] Figure 6 is a schematic diagram of the liquid discharge head of modified example 2. In this modified example 2, in a cross-section cut in the direction of liquid discharge, the side wall surface 120a of the common liquid chamber 3 is inclined so that it is located outward in the direction of nozzle alignment as it moves away from the pressurized liquid chamber 4. By making the side wall surface 120a inclined in this way, air bubbles can easily escape upward. In addition, the angle θ2 between the bottom surface of the common liquid chamber 3 and the side wall surface 120a becomes obtuse, making it easier for the liquid to flow between the bottom surface and the side wall surface. As a result, it is possible to suppress the formation of air bubbles at the corner between the bottom surface of the common liquid chamber 3 and the side wall surface 120a during filling, and the liquid filling performance can be improved.

[0036] In Figure 6, the entire side wall surface 120a is shown as an inclined surface, but it is also possible to make only the side wall surface 120a on the pressurized liquid chamber side an inclined surface. With this configuration as well, the angle θ2 between the bottom surface of the common liquid chamber 3 and the side wall surface 120a can be made obtuse, thereby improving the liquid filling efficiency.

[0037] Furthermore, as shown in Figure 7, it is preferable to make the connection portion 120b between the side wall surface 120a of the common liquid chamber 3 and the ceiling surface 3a rounded (R-shape), so that the angle θ3 between the ceiling surface 3a and the side wall surface 120a is obtuse. This makes it easier for air to escape from the connection portion between the ceiling surface 3a and the side wall surface 120a during filling, and suppresses the formation of air bubbles at the connection portion between the ceiling surface 3a and the side wall surface 120a. This further improves the liquid filling efficiency. Also, as shown in Figure 7, making the connection portion 120b rounded (R-shape) makes the connection between the inclined side wall surface 120a and the connection portion 120b smoother, making it easier for air to move upward during filling and further suppressing the generation of air bubbles.

[0038] Next, an example of a liquid dispensing apparatus according to the present invention will be described with reference to Figures 8 and 9. Figure 8 is a schematic diagram illustrating a printing apparatus, which is an inkjet recording apparatus used as a liquid ejection device in this embodiment. Figure 9 is a plan view illustrating an example of the head unit of the printing apparatus according to this embodiment.

[0039] The printing apparatus 500, which is a device that discharges this liquid, includes a loading means 501 for loading the continuous body 510, and a guiding and transporting means 503 for guiding and transporting the continuous body 510 loaded from the loading means 501 to the printing means 505. The printing apparatus 500 also includes a printing means 505 for printing an image by discharging liquid onto the continuous body 510, a drying means 507 for drying the continuous body 510, and an unloading means 509 for unloading the continuous body 510.

[0040] The continuous body 510 is fed out from the main winding roller 511 of the loading means 501, guided and transported by the rollers of the loading means 501, the guiding and transporting means 503, the drying means 507, and the unloading means 509, and then wound up by the winding roller 591 of the unloading means 509. In the printing means 505, this continuous body 510 is transported on the transport guide member 559 facing the head unit 550, and an image is printed by the liquid discharged from the head unit 550.

[0041] In the printing apparatus 500 of this embodiment, the head unit 550 is equipped with the two head modules 100A and 100B described above in this embodiment on a common base member 552.

[0042] Then, when the direction in which the liquid discharge heads 1 are arranged in a direction perpendicular to the transport direction of head modules 100A and 100B is defined as the head array direction, the head rows 1A1 and 1A2 of head module 100A discharge liquid of the same color. Similarly, the head rows 1B1 and 1B2 of head module 100A are paired, the head rows 1C1 and 1C2 of head module 100B are paired, and the head rows 1D1 and 1D2 are paired, and the required color liquid is discharged from each.

[0043] Next, other examples of printing apparatus as a liquid dispensing device according to the present invention will be described with reference to Figures 10 and 11. Figure 10 is a plan view illustrating the main components of the printing apparatus in this example. Figure 11 is a side view illustrating the main components of the printing apparatus in this example.

[0044] The printing apparatus 500 in this example is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction by the 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 stretched across the left and right side plates 491A and 491B and holds the carriage 403 in a movable position. The carriage 403 is then reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 stretched between the drive pulley 406 and the driven pulley 407.

[0045] The carriage 403 is equipped with a liquid discharge unit 440 that integrates a liquid discharge head 1 and a head tank 441 according to the present invention. The liquid discharge head 1 discharges liquids of various colors, such as yellow (Y), cyan (C), magenta (M), and black (K). The liquid discharge head 1 is also mounted with a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and with the discharge direction facing downward. The liquid discharge head 1 is connected to a liquid circulation device, and the required color of liquid is circulated and supplied.

[0046] 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 picks up the paper 410 and transports it to a position facing the liquid discharge head 1. This transport belt 412 is an endless belt and is stretched between a transport roller 413 and a tension roller 414. Pickup can be performed 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.

[0047] Furthermore, a maintenance and recovery mechanism 420 for maintaining and restoring the liquid discharge head 1 is positioned on one side of the carriage 403 in the main scanning direction, next to the transport belt 412. The maintenance and recovery mechanism 420 consists of, for example, a cap member 421 that caps the nozzle surface of the liquid discharge head 1, and a wiper member 422 that wipes the nozzle surface. The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the transport mechanism 495 are mounted on a housing that includes side plates 491A, 491B, and a back plate 491C.

[0048] In the printing apparatus 500 configured in this way, the paper 410 is fed onto the transport belt 412 and held in place, and the paper 410 is transported in the sub-scanning direction by the circular movement of the transport belt 412. Then, by moving the carriage 403 in the main scanning direction and driving the liquid ejection head 1 in accordance with the image signal, liquid is ejected onto the stationary paper 410 to form an image.

[0049] Next, another example of the liquid dispensing unit according to the present invention will be described with reference to Figure 12. Figure 12 is a plan view illustrating the main components of the liquid dispensing unit in this example.

[0050] The liquid discharge unit 440 consists of a housing portion comprising side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid discharge head 1, which are components of the device that discharges the liquid.

[0051] Furthermore, a liquid dispensing unit can also be configured by attaching the aforementioned maintenance and recovery mechanism 420 to, for example, the side plate 491B of the liquid dispensing unit 440.

[0052] Next, yet another example of the liquid dispensing unit according to the present invention will be described with reference to Figure 13. Figure 13 is a front view of the liquid dispensing unit in this example.

[0053] This liquid discharge unit 440 consists of a liquid discharge head 1 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

[0054] The flow path component 444 is located inside the cover 442. A head tank 441 can be included instead of the flow path component 444. Furthermore, a contact 443 is provided on the upper part of the flow path component 444 for electrical connection with the liquid discharge head 1.

[0055] In this application, the discharged liquid is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the head, but it is preferable that its viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or when heated or cooled. More specifically, it is a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a functional material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment. These can be used, for example, in inkjet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements or electronic circuit resist patterns, and material liquids for 3D molding.

[0056] The energy source for discharging liquid includes piezoelectric actuators (multilayer piezoelectric elements and thin-film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a diaphragm and a counter electrode.

[0057] A "liquid discharge unit" is a liquid discharge head with integrated functional components and mechanisms, and includes an assembly of parts related to liquid discharge. For example, a "liquid discharge unit" may include a combination of a liquid discharge head with at least one of the following components: a head tank, carriage, supply mechanism, maintenance and recovery mechanism, main scanning movement mechanism, and liquid circulation device.

[0058] Here, integration includes, for example, cases where the liquid dispensing head and functional components or mechanisms are fixed to each other by fastening, bonding, engaging, etc., or where one is held movably relative to the other. Furthermore, the liquid dispensing head and functional components or mechanisms may be configured to be detachable from each other.

[0059] For example, some liquid dispensing units have a liquid dispensing head and head tank integrated into one unit. Others have a liquid dispensing head and head tank integrated into one unit, connected to each other by tubes or similar means. In these liquid dispensing units, a unit including a filter can also be added between the head tank and the liquid dispensing head.

[0060] Additionally, some liquid dispensing units have an integrated liquid dispensing head and carriage.

[0061] Furthermore, some liquid dispensing units integrate the liquid dispensing head and the scanning mechanism by movably holding the liquid dispensing head in a guide member that constitutes part of the scanning mechanism. Others integrate the liquid dispensing head, carriage, and main scanning mechanism.

[0062] Furthermore, some liquid dispensing units integrate the liquid dispensing head, carriage, and maintenance / recovery mechanism by fixing a cap component, which is part of the maintenance / recovery mechanism, to a carriage to which the liquid dispensing head is attached.

[0063] Furthermore, some liquid discharge units have a head tank or a liquid discharge head to which flow path components are attached, to which a tube is connected, integrating the liquid discharge head and the supply mechanism. Through this tube, the liquid from the liquid storage source is supplied to the liquid discharge head.

[0064] The main scanning movement mechanism shall include the guide member alone. The supply mechanism shall also include the tube alone and the loading section alone.

[0065] Here, the "liquid dispensing unit" is described in combination with a liquid dispensing head, but the "liquid dispensing unit" also includes a head module or head unit that includes the liquid dispensing head mentioned above, as well as the functional components and mechanisms described above, all integrated together.

[0066] "Liquid dispensing devices" include devices that have a liquid dispensing head, liquid dispensing unit, head module, head unit, etc., and drive the liquid dispensing head to dispense liquid. Liquid dispensing devices include not only devices that can dispense liquid onto surfaces to which liquid can adhere, but also devices that dispense liquid into air or into liquid.

[0067] This "liquid dispensing device" may also include means for feeding, transporting, and dispensing paper onto materials to which liquid can adhere, as well as pre-treatment devices, post-treatment devices, etc.

[0068] For example, "devices that dispense liquids" include image forming machines, which dispense ink to form images on paper, and three-dimensional molding machines, which dispense molding liquid into a powder layer formed in layers to create three-dimensional objects.

[0069] Furthermore, "devices that dispense liquid" are not limited to those that visualize meaningful images such as letters or figures through the dispensed liquid. For example, devices that form patterns that do not have meaning in themselves, or devices that create three-dimensional images, are also included.

[0070] The term "materials to which liquid can adhere" above refers to materials to which liquid can adhere, at least temporarily, including materials that adhere and solidify, or materials that adhere and penetrate. Specific examples include recording media such as paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and inspection cells. Unless otherwise specified, it includes all materials to which liquid can adhere.

[0071] The materials referred to as "materials to which liquid can adhere" above include paper, thread, fibers, fabrics, leather, metal, plastic, glass, wood, ceramics, etc., as long as liquid can adhere to them, even temporarily.

[0072] Furthermore, "liquid dispensing devices" include devices in which the liquid dispensing head and the surface to which the liquid can adhere move relative to each other, but are not limited to these. Specific examples include serial-type devices in which the liquid dispensing head moves, and line-type devices in which the liquid dispensing head does not move.

[0073] Furthermore, other types of "liquid dispensing devices" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the paper's surface. There are also spray granulation devices that granulate fine particles of raw materials by spraying a compositional liquid, in which raw materials are dispersed in a solution, through a nozzle.

[0074] In this application, the terms image formation, recording, printing, copying, printing, and shaping are all considered synonymous.

[0075] The above is just one example; each of the following embodiments produces its own unique effects. (Aspect 1) In a liquid discharge head that supplies liquid from a common liquid chamber 3 to pressurized liquid chambers 4, each communicating with a plurality of nozzles 2, and drives an electromechanical conversion element such as a piezoelectric element 5 located on the nozzle side relative to the pressurized liquid chamber 4 to discharge the liquid in the pressurized liquid chamber from the nozzle 2, each pressurized liquid chamber 4 has an opening on the opposite side from the communication port side that communicates with the nozzle 2, to which liquid is supplied from the common liquid chamber 3, and the cross-sectional area of ​​the opening side of each pressurized liquid chamber 4 increases as it approaches the common liquid chamber 3. According to this, as described in the embodiment, by increasing the cross-sectional area of ​​the opening side of the pressurized liquid chamber toward the common liquid chamber, the pressure on the liquid on the opening side of the pressurized liquid chamber decreases toward the common liquid chamber. As a result, pressure fluctuations toward the common liquid chamber from the pressurized liquid chamber can be reduced on the opening side of the pressurized liquid chamber, and pressure fluctuations propagated to the common liquid chamber can be weakened. This suppresses the effect of pressure fluctuations propagated to the common liquid chamber on the discharge of liquid in another pressurized liquid chamber, thereby reducing crosstalk.

[0076] (Aspect 2) In embodiment 1, the cross-sectional area is constant in the nozzle-side region compared to the region where the cross-sectional area increases towards the common liquid chamber 3 on the opening side of each pressurized liquid chamber 4. According to this, compared to the configuration described in the embodiment in which the cross-sectional area of ​​the entire pressurized liquid chamber gradually increases toward the common liquid chamber, it is possible to suppress the widening of the distance between nozzles and to increase the density of nozzles. Furthermore, compared to the configuration in which the cross-sectional area of ​​the entire pressurized liquid chamber gradually increases toward the common liquid chamber, it is possible to reduce the pressure fluctuations propagated from the pressurized liquid chamber 4 to the common liquid chamber 3.

[0077] (Aspect 3) In embodiment 1, the cross-sectional area of ​​each pressurized liquid chamber 4 on the nozzle side is reduced as it approaches the nozzle 2. According to this, as explained in Modification 1, even if the meniscus of nozzle 2 is destroyed by impact or the like and moves to the pressurized liquid chamber, the meniscus of the nozzle can be restored naturally.

[0078] (Aspect 4) In embodiment 3, the region between the region where the cross-sectional area increases toward the common liquid chamber 3 on the opening side of each pressurized liquid chamber 4 and the region where the cross-sectional area decreases toward the nozzle 2 on the nozzle side has a constant cross-sectional area. According to this, compared to the configuration described in Modification 1, where the cross-sectional area of ​​the entire pressurized liquid chamber gradually increases toward the common liquid chamber, it is possible to suppress the widening of the distance between nozzles and to increase the density of nozzles. Furthermore, compared to the configuration where the cross-sectional area of ​​the entire pressurized liquid chamber gradually increases toward the common liquid chamber, it is possible to reduce the pressure fluctuations propagating from the pressurized liquid chamber 4 to the common liquid chamber 3.

[0079] (Appendix 5) In any of embodiments 1 to 4, in a cross-section cut parallel to the liquid discharge direction, the side wall surface 120a of the common liquid chamber 3 is an inclined surface such that it is located further outward as it moves away from the pressurized liquid chamber 4. According to this, as explained in Modification 2, air bubbles can easily escape upwards. Also, the angle θ2 between the bottom surface and the side wall surface 120a of the common liquid chamber 3 becomes obtuse, making it easier for the liquid to flow between the bottom surface and the side wall surface. As a result, it is possible to suppress the formation of air bubbles at the corner between the bottom surface and the side wall surface 120a of the common liquid chamber 3 during filling, and the liquid filling efficiency can be improved.

[0080] (Aspect 6) In any of embodiments 1 to 5, the angle θ3 between the side wall surface 120a of the common liquid chamber 3 and the ceiling surface 3a of the common liquid chamber in a cross section parallel to the liquid discharge direction is obtuse. According to this, as explained using Figure 7, it is possible to suppress the generation of air bubbles at the connection between the ceiling surface 3a and the side wall surface 120a, thereby improving the liquid filling performance.

[0081] (Aspect 7) In embodiment 6, in a cross-section parallel to the liquid discharge direction, the connection portion 120b between the side wall surface 120a of the common liquid chamber 3 and the ceiling surface 3a of the common liquid chamber 3 is given an R shape. According to this, as explained using Figure 7, the connection between the connection portion 120b of the side wall surface 120a and the rest of the surface becomes smoother, making it easier for air to move upwards during filling, and further suppressing the generation of air bubbles.

[0082] (Pattern 8) In any of embodiments 1 to 7, the substrate is such as a flow channel substrate 100 having a plurality of pressurized liquid chambers 4, a common liquid chamber 3 is formed on the side of the substrate opposite to the nozzle side, and the entire side of each pressurized liquid chamber 4 opposite to the nozzle side opens into the common liquid chamber 3.

[0083] (Aspect 9) In any of embodiments 1 to 8, the device includes a substrate such as a flow channel substrate 100 having a plurality of pressurized liquid chambers 4, and a vibrating membrane 103 laminated on the nozzle side of the substrate and constituting a part of the wall surface of the pressurized liquid chamber, and an electromechanical conversion element such as a piezoelectric element 5 is arranged on the side of the vibrating membrane 103 opposite to the side that constitutes the wall surface of the pressurized liquid chamber 4.

[0084] (Aspect 10) A liquid discharge unit comprising a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and at least one of a main scanning movement mechanism, and a liquid discharge head, wherein any liquid discharge head from embodiment 1 to 9 is used as the liquid discharge head. According to this method, crosstalk can be suppressed.

[0085] (Aspect 11) A device for dispensing liquid has a liquid dispensing head according to any of embodiments 1 to 9, or a liquid dispensing unit according to embodiment 10. According to this method, crosstalk can be suppressed. [Explanation of Symbols]

[0086] 1: Liquid dispensing head 2: Nozzle 3: Common liquid chamber 3a:Ceiling surface 4: Pressurized liquid chamber 4a: Bulkhead 5: Piezoelectric element 6: Electrical connection pad 7a: First Contact 7b: Second Contact 8a: First insulating film 8b: Second insulating film 9a: First pullout wiring 9b: Second pullout wiring 10: Pad opening 41: Tip 42: Nozzle side 51:First electrode 52: Piezoelectric film 53:Second electrode 100: Flow channel substrate 103: Vibrating membrane 110: Actuator section 111: Nozzle forming section 120: Frame component 120a: Side wall surface 120b: Connection part 440: Liquid Dispensing Unit 441: Head Tank [Prior art documents] [Patent Documents]

[0087] [Patent Document 1] Japanese Patent Publication No. 2019-191184

Claims

1. In a liquid discharge head that supplies liquid from a common liquid chamber to pressurized liquid chambers communicating with multiple nozzles, and drives an electromechanical conversion element located on the nozzle side relative to the pressurized liquid chamber to discharge the liquid in the pressurized liquid chamber from the nozzle, Each pressurized liquid chamber has an opening on the side opposite to the nozzle side to which the liquid is supplied from the common liquid chamber. The cross-sectional area of ​​the opening side of each pressurized liquid chamber increases as it approaches the common liquid chamber. A liquid discharge head characterized in that the cross-sectional area of ​​the nozzle side region is constant compared to the region of each pressurized liquid chamber where the cross-sectional area increases as it approaches the common liquid chamber on the opening side.

2. A liquid discharge head that supplies liquid from a common liquid chamber to pressurized liquid chambers communicating with each of a plurality of nozzles, and drives an electromechanical conversion element located on the nozzle side relative to the pressurized liquid chamber to discharge the liquid in the pressurized liquid chamber from the nozzle, Each pressurized liquid chamber has an opening on the side opposite to the nozzle side to which the liquid is supplied from the common liquid chamber. The cross-sectional area of ​​the opening side of each pressurized liquid chamber increases as it approaches the common liquid chamber. The cross-sectional area of ​​the nozzle side of each pressurized liquid chamber is gradually reduced as it approaches the nozzle. A liquid discharge head characterized in that the region between the region of each pressurized liquid chamber that increases toward the common liquid chamber on the opening side and the region on the nozzle side that decreases toward the nozzle has a constant cross-sectional area.

3. In the liquid dispensing head according to claim 1 or 2, A liquid discharge head characterized in that, in a cross-section parallel to the liquid discharge direction, the side wall surface of the common liquid chamber is an inclined surface such that it is located further outward as it moves away from the pressurized liquid chamber.

4. In the liquid dispensing head according to any one of claims 1 to 3, A liquid discharge head characterized in that, in a cross-section parallel to the liquid discharge direction, the angle between the side wall surface of the common liquid chamber and the ceiling surface of the common liquid chamber is obtuse.

5. In the liquid discharge head according to claim 4, A liquid discharge head characterized in that, in a cross-section parallel to the liquid discharge direction, the connection portion between the side wall surface of the common liquid chamber and the ceiling surface of the common liquid chamber is R-shaped.

6. In the liquid dispensing head according to any one of claims 1 to 5, Having a substrate with multiple pressurized liquid chambers, The common liquid chamber is formed on the side of the substrate opposite to the nozzle side. A liquid dispensing head characterized in that the entire opposite side of each pressurized liquid chamber from the nozzle side is open to the common liquid chamber.

7. In the liquid dispensing head according to any one of claims 1 to 6, A substrate having multiple pressurized liquid chambers, The substrate is laminated on the nozzle side and has a vibrating membrane that forms part of the wall surface of the pressurized liquid chamber, The liquid discharge head is characterized in that the electromechanical conversion element is arranged on the side of the vibrating membrane opposite to the side that constitutes the wall of the pressurized liquid chamber.

8. A liquid discharge unit comprising a head tank, carriage, supply mechanism, maintenance and recovery mechanism, and at least one of a main scanning movement mechanism, and a liquid discharge head, A liquid dispensing unit characterized in that the liquid dispensing head used is the liquid dispensing head described in any one of claims 1 to 7.

9. In a device that dispenses liquid, A liquid dispensing device characterized by having a liquid dispensing head according to any one of claims 1 to 7, or a liquid dispensing unit according to claim 8.

Images