Liquid dispensing head and device for dispensing liquid

Abstract

To inhibit residual vibration generating in a nozzle formation layer after liquid discharge by a drive waveform.SOLUTION: A liquid discharging device comprises a nozzle formation layer having a piezoelectric layer, a nozzle penetrating the nozzle formation layer, a liquid chamber communicating with the nozzle, and a drive circuit impressing a driving waveform W1 to make the piezoelectric layer drive. When a natural oscillation period is set to Tc, the driving waveform W1 has a first waveform W11 impressing a drive voltage by which the liquid in the liquid chamber is discharged from the nozzle, and a second waveform W12 impressing a fall element of the voltage at a timing T12 of n×Tc (n is a positive integer) against the rise element U11 of the voltage.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] In a liquid ejection head, a technique of driving a nozzle formation layer as an actuator to eject liquid in order to increase the density of nozzles has been considered and is already known. However, residual vibration occurs in the nozzle formation layer after liquid ejection, and there has been a problem that the speed of ejecting the next liquid fluctuates and a normal image cannot be obtained. For example, Patent Document 1 discloses a configuration in which a damper is arranged without providing a dedicated damper chamber for the purpose of suppressing vibration in an individual liquid chamber, but the above-described problem cannot be solved.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to suppress residual vibration generated in a nozzle formation layer after liquid ejection by a driving waveform.

Means for Solving the Problems

[0004] In order to solve the above-described problems, the liquid ejection head of the present invention includes a nozzle formation layer having a piezoelectric layer, nozzles penetrating the nozzle formation layer, a liquid chamber communicating with the nozzles, and a drive circuit that applies a drive waveform to drive the piezoelectric layer. When the natural vibration period of the piezoelectric layer is Tc, The drive waveform comprises multiple waveforms that decrease and then increase the voltage, a first waveform having an element that increases the voltage of the drive voltage that applies a drive voltage to discharge the liquid from the liquid chamber from the nozzle, a third waveform that maintains the termination voltage of the element that increases the voltage of the drive voltage, and a second waveform having a voltage reduction element that applies a drive voltage that decreases the voltage from the termination voltage of the element that increases the voltage of the drive voltage at a timing of n × Tc (where n is a positive integer) relative to the start of the element that increases the voltage of the drive voltage. The first waveform and the third waveform The second waveform is continuous with the aforementioned waveform. The first waveform consists of an element that increases the voltage of the drive voltage, and a waveform element that, prior to the element that increases the voltage of the drive voltage, changes the voltage from the termination voltage of the element that increases the voltage of the drive voltage to the starting voltage of the element that increases the voltage of the drive voltage, and maintains the starting voltage of the element that increases the voltage of the drive voltage. The second waveform consists of the voltage reduction element and, after the voltage reduction element, a waveform element that maintains the termination voltage of the voltage reduction element and then changes the voltage from the termination voltage of the voltage reduction element to the termination voltage of the element that increases the drive voltage. The amplitude of the drive voltage is characterized by being greater than the amplitude of the voltage applied in the second waveform. [Effects of the Invention]

[0005] According to the present invention, residual vibrations generated in the nozzle forming layer after liquid discharge can be suppressed by the drive waveform. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic cross-sectional view of a liquid discharge head according to an embodiment of the present invention. [Figure 2] This is a schematic plan view of the liquid dispensing head. [Figure 3] This figure illustrates an example of a drive waveform according to Embodiment 1. [Figure 4]This figure illustrates the effect of the drive waveform of Embodiment 1, where (a) is an example of the drive waveform of the comparative example, (b) is an example of the drive waveform of this embodiment, and (c) shows the meniscus displacement when the waveforms of the comparative example and this embodiment are applied. [Figure 5] This figure illustrates an example of a drive waveform according to Embodiment 2. [Figure 6] This figure illustrates the effect of the drive waveform of Embodiment 2, where (a) is an example of the drive waveform of the comparative example, (b) is an example of the drive waveform of this embodiment, and (c) shows the meniscus displacement when the waveforms of the comparative example and this embodiment are applied. [Figure 7] This figure illustrates an example of a drive waveform according to Embodiment 3. [Figure 8] This figure illustrates the effect of the drive waveform of Embodiment 3, where (a) is an example of the drive waveform of the comparative example, (b) is an example of the drive waveform of this embodiment, and (c) shows the meniscus displacement when the waveforms of the comparative example and this embodiment are applied. [Figure 9] This is a plan view illustrating the main parts of an example of a liquid dispensing device according to the present invention. [Figure 10] This is a side view illustrating the main components of the device. [Figure 11] This is a plan view illustrating the main part of an example of a liquid dispensing unit according to the present invention. [Figure 12] This is a front view illustrating another example of the liquid dispensing unit according to the present invention. [Modes for carrying out the invention]

[0007] Embodiments of the present invention will be described below with reference to the drawings. However, 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. Furthermore, components and corresponding parts having the same configuration or function in each drawing are denoted by the same reference numerals, and their descriptions are omitted.

[0008] (Liquid dispensing head) FIG. 1 is a schematic cross-sectional view of a liquid ejection head according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the liquid ejection head, as viewed from the nozzle surface side (also referred to as the side from which liquid is ejected). The view seen from the direction of arrow a in FIG. 1 corresponds to FIG. 2, and FIG. 1 is a cross-sectional view taken along line A-A of FIG. 2. As shown in FIG. 1, the liquid ejection head of the present embodiment includes a nozzle formation layer 1, a liquid chamber formation substrate 2, and a drive circuit 92.

[0009] The nozzle formation layer 1 has a vibration layer 3, a piezoelectric actuator 12 that is a piezoelectric layer, an electrode pad 90, a first protective layer 81, and a second protective layer 82. The electrode pad 90 is an example of a circuit connection portion.

[0010] The nozzle formation layer 1 has a nozzle 4, and liquid (for example, ink) is ejected from the nozzle 4. The liquid in the liquid chamber 6 formed by a part of the nozzle formation layer 1 and the liquid chamber formation substrate 2 is ejected from the nozzle 4 by driving the piezoelectric actuator 12.

[0011] The vibration layer 3 vibrates by driving the piezoelectric actuator 12. The material of the vibration layer 3 is not particularly limited, and for example, Al2O3, SiN, SiO2, HTO (High Temperature Oxide), or a configuration in which several of these materials are laminated can be used.

[0012] The liquid chamber formation substrate 2 has a liquid chamber 6 that communicates with the nozzle 4. A circuit protection layer 17 is formed between the liquid chamber formation substrate 2 and the vibration layer 3. The circuit protection layer 17 has a function of protecting the drive circuit 92 and the interlayer wiring layer 95.

[0013] The material of the circuit protection layer 17 is not particularly limited, and examples thereof include PTFE (polytetrafluoroethylene)-based resins and the like. Also, the location where the circuit protection layer 17 is formed is not particularly limited, and for example, it is formed so as to cover the drive circuit 92 and the interlayer wiring layer 95. The nozzle forming layer 1 may have the circuit protection layer 17, or the liquid chamber forming substrate 2 may have the circuit protection layer 17.

[0014] The piezoelectric actuator 12 has a lower electrode 21, a piezoelectric body 22, and an upper electrode 23. The lower electrode 21 may be used as a common electrode and the upper electrode 23 as an individual electrode, or the lower electrode 21 may be used as an individual electrode and the upper electrode 23 as a common electrode.

[0015] The piezoelectric body 22 is not particularly limited, and for example, PZT (lead zirconate titanate) or the like can be used. Also, the lower electrode 21 and the upper electrode 23 are not particularly limited, and known electrode materials can be used. For example, Pt and the like can be mentioned.

[0016] The piezoelectric actuator 12 or the piezoelectric body 22 is formed in the vicinity of the nozzle 4 on the side where the liquid in the vibration layer 3 is discharged (the nozzle surface side). It may also be described that the piezoelectric actuator 12 is formed on the vibration layer 3. By forming the piezoelectric actuator 12 at such a location, a vibration plate for applying pressure to the liquid sucked and introduced into the liquid chamber 6 and discharging it from the nozzle 4 becomes unnecessary.

[0017] The piezoelectric actuator 12 is connected to the drive circuit 92 via connection electrodes 94b and 94c. Here, for example, the lower electrode 21 is connected to the drive circuit 92 via the connection electrode 94b, and the upper electrode 23 is connected to the drive circuit 92 via the connection electrode 94c.

[0018] As shown in Figure 1, a piezoelectric actuator 12a may be provided that is not connected to the drive circuit 92 and does not contribute to the discharge of liquid. Such a piezoelectric actuator 12a can be used, for example, as a guide for the nozzle formation position when forming the nozzle 4.

[0019] The drive circuit 92 is connected to the electrode pad 90 and is powered from the power supply unit via the electrode pad 90 and connecting electrode 94a. The drive circuit 92 is formed on the opposite side of the vibrating layer 3 from the electrode pad 90. Although not limited, it is preferable that the drive circuit 92 be formed on the liquid chamber forming substrate 2. In this case, there is the advantage that it is easier to manufacture when forming the drive circuit 92.

[0020] The drive circuit 92 is not particularly limited, but for example, it can be a CMOS circuit. Also, although not particularly limited, the drive circuit 92 is shown separately as a part on the electrode pad 90 side and a part on the piezoelectric actuator 12 side, and these parts are connected by an interlayer wiring layer 95. For example, known electrode materials can be used for the interlayer wiring layer 95.

[0021] The electrode pad 90 (circuit connection portion) is formed on the side of the vibrating layer 3 where the liquid is discharged (nozzle surface side) and is connected to the drive circuit 92 via the connecting electrode 94a. Although two connecting electrodes 94a are shown here, the diagram does not limit the possibilities. The diagram shows two connecting electrodes 94b and 94c, which correspond to the lower electrode 21 and upper electrode 23 of the piezoelectric actuator 12.

[0022] As shown in the figure, in this embodiment, protective layers 81 and 82 are formed on the side from which the liquid is discharged (nozzle surface side). The first protective layer 81 is formed around the electrode pad 90 and also forms the opening 85 of the electrode pad 90. The second protective layer 82 is formed on the piezoelectric actuator 12. By forming the first protective layer 81 and the second protective layer 82, at least one of the components, such as the piezoelectric actuator 12, the vibration layer 3, and the electrode pad 90, can be protected, thereby preventing deterioration of the components.

[0023] The liquid discharge head of this embodiment has a water-resistant film 88 formed on the surfaces of the first protective layer 81 and the second protective layer 82. By having the water-resistant film 88, water penetration can be more effectively blocked, and problems such as deterioration of the performance of the piezoelectric actuator 12 due to the influence of moisture penetrating through the protective layer can be more effectively suppressed. Note that the water-resistant film 88 is not shown in Figure 2.

[0024] In this embodiment, the first protective layer 81 and the second protective layer 82 are not continuous. As shown in the figure, the first protective layer 81 and the second protective layer 82 are separated from each other by a separation groove 86 and are discontinuous. In this way, in a liquid discharge head in which a piezoelectric actuator 12 and an electrode pad 90 (circuit connection part) are formed on the nozzle forming layer 1, it is possible to suppress the deterioration of the piezoelectric performance of the piezoelectric actuator 12 due to moisture absorption from the opening 85 of the electrode pad 90.

[0025] The liquid discharge head of this embodiment is not limited to the configuration described above. The liquid discharge head of this embodiment only needs to include at least a nozzle forming layer 1 having a piezoelectric layer, a nozzle 4 penetrating the nozzle forming layer, a liquid chamber 6 communicating with the nozzle 4, and a drive circuit 92 that applies a drive waveform to drive the piezoelectric layer, and may not have the other components described with reference to Figures 1 and 2.

[0026] Next, the drive waveform used by the liquid discharge head of this embodiment will be described. In this embodiment, in a liquid discharge head with a structure that does not have individual liquid chambers, residual vibrations generated in the nozzle forming layer when discharge are suppressed by using a drive waveform.

[0027] The drive waveform applied by the drive circuit to the piezoelectric layer has a first waveform and a second waveform. The first waveform represents the portion of the waveform that applies a driving voltage to the piezoelectric layer to cause liquid to be ejected from the nozzle. The second waveform is the portion of the waveform that applies a suppression voltage to suppress residual vibrations generated in the nozzle formation layer. The drive voltage should have a larger amplitude than the suppression voltage.

[0028] The drive waveform of this embodiment is configured to apply a suppression voltage to the rising element of the drive voltage at a predetermined timing. More specifically, the drive waveform is configured such that a falling or rising element of the suppression voltage is applied to the rising element of the drive voltage at a predetermined timing. The predetermined timing is calculated using the timing of applying the rise element of the drive voltage and the natural oscillation period. Here, the predetermined timing may be calculated each time a drive waveform is applied to the liquid discharge head, or it may be calculated in advance during the manufacturing of the liquid discharge head and stored in the memory of the liquid discharge head. Alternatively, a drive waveform having the calculated predetermined timing may be stored in the memory. The natural vibration period is defined as the primary natural vibration period of the piezoelectric layer when the liquid chamber and nozzle are filled with liquid. In the following explanation, the natural vibration period will be referred to as "Tc" as appropriate.

[0029] This approach makes it possible to suppress residual vibrations generated in the nozzle formation layer by the drive waveform without adding any new mechanical mechanisms. The details of the drive waveform are described below for each embodiment.

[0030] Embodiment 1. Figure 3 illustrates an example of a drive waveform according to Embodiment 1. Figure 3 and Figures 5 and 7, described later, schematically show the drive waveform, with voltage (volts) on the vertical axis and time (microseconds) on the horizontal axis. In Embodiment 1, the drive waveform W1 has a rising element U11 for the drive voltage of the first waveform W11, and the second waveform W12 has a falling element D12 for the suppression voltage at a timing T12 of n × Tc (where n is a positive integer).

[0031] As shown in Figure 3, among the multiple waveform elements of the first waveform W11, the drive voltage rise element U11 that brings about a voltage change when the drive voltage rises, and among the multiple waveform elements of the second waveform W12, the suppression voltage fall element D12 that brings about a voltage change different from that of the drive voltage rise element U11, are separated by an interval of n × Tc. Figure 3 shows the interval (n × Tc) between the timing T11 at which the drive voltage rise element U11 starts and the timing T12 at which the suppression voltage fall element D12 starts. It is preferable that the suppression voltage fall element D12 be provided over the range from the start to the end of the drive voltage rise element U11 (the sloped portion in the figure).

[0032] The effects of the drive waveform in this embodiment will be explained. Figure 4 illustrates the effect of the drive waveform of Embodiment 1, where (a) is an example of the drive waveform of the comparative example, (b) is an example of the drive waveform of this embodiment, and (c) shows the meniscus displacement when the waveforms of the comparative example and this embodiment are applied. In Figure 4, the values ​​of the comparative example are shown with solid lines, and the values ​​of this embodiment are shown with dashed lines. In the case of a liquid dispensing head configuration as shown in Figure 1, residual vibration occurs in the nozzle forming layer after dispensing.

[0033] Using the drive waveform W1 shown in Figure 3, the drive circuit 92 applies a suppression voltage drop-off element D12 to the drive voltage rise-up element U11 at a timing T12 of n × Tc. As a result, the liquid discharge head can cancel out vibrations generated by discharge and suppress residual vibrations generated in the nozzle formation layer. Thus, the drive waveform W1 has a waveform configuration that can suppress residual vibrations generated in the nozzle formation layer.

[0034] Embodiment 2. Figure 5 is a diagram illustrating an example of a drive waveform according to Embodiment 2. In Embodiment 2, the drive waveform W2 has a rise element U22 for suppression voltage at a timing T22 of (m-0.5) × Tc (where m is a positive integer) relative to the rise element U21 of the drive voltage of the first waveform W21.

[0035] As shown in Figure 5, the drive voltage rise element U21, which brings about a voltage change when the drive voltage is raised, and the suppression voltage rise element U22, which brings about the same voltage change as the drive voltage rise element U21, are separated by a distance of (m-0.5) × Tc. Figure 5 shows the interval ((m-0.5)×Tc) between the timing T21 when the drive voltage rise element U21 starts and the timing T22 when the suppression voltage rise element U22 starts. It is preferable that the suppression voltage rise element U22 is provided for the range from the start to the end of the drive voltage rise element U11.

[0036] The effects of the drive waveform in this embodiment will be explained. Figure 6 illustrates the effect of the drive waveform of Embodiment 2, where (a) is an example of the drive waveform of the comparative example, (b) is an example of the drive waveform of this embodiment, and (c) shows the meniscus displacement when the waveforms of the comparative example and this embodiment are applied. In Figure 6, the values ​​of the comparative example are shown with solid lines, and the values ​​of this embodiment are shown with dashed lines.

[0037] Using the drive waveform W2 shown in Figure 5, the drive circuit 92 applies a suppression voltage rise element U22 to the drive voltage rise element U21 at a timing T22 of (m-0.5) × Tc. As a result, the liquid discharge head can cancel out vibrations generated by discharge and suppress residual vibrations generated in the nozzle forming layer. Thus, the drive waveform W2 has a waveform configuration that can suppress residual vibrations generated in the nozzle formation layer.

[0038] Embodiment 3. Figure 7 illustrates an example of a drive waveform according to Embodiment 3. In Embodiment 3, the drive waveform W3 has a rising element U31 for the drive voltage of the first waveform W31, and the second waveform W32 has a falling element D32 for the suppression voltage at a timing T32 of n × Tc, and a rising element U32 for the suppression voltage at a timing T33 of (m - 0.5) × Tc.

[0039] As shown in Figure 7, the drive voltage rise element U31 and the suppression voltage drop element D32, which produces a different voltage change from the drive voltage rise element U31, are separated by an interval of n × Tc. Also, the drive voltage rise element U31 and the suppression voltage rise element U32, which produces the same voltage change as the drive voltage rise element U31, are separated by an interval of (m - 0.5) × Tc. Figure 7 shows the interval (n × Tc) between the timing T31 at which the rise element U31 of the drive voltage starts and the timing T32 at which the fall element D12 of the suppression voltage starts, and the interval ((m - 0.5) × Tc) between the timing T31 at which the rise element U32 of the suppression voltage starts. It is preferable that the fall element D32 of the suppression voltage and the rise element U32 of the suppression voltage are provided within the range from the start to the end of the rise element U11 of the drive voltage.

[0040] The effects of the drive waveform in this embodiment will be explained. Figure 8 illustrates the effect of the drive waveform of Embodiment 3, where (a) is an example of the drive waveform of the comparative example, (b) is an example of the drive waveform of this embodiment, and (c) shows the meniscus displacement when the waveforms of the comparative example and this embodiment are applied. In Figure 8, the values ​​of the comparative example are shown with solid lines, and the values ​​of this embodiment are shown with dashed lines.

[0041] Using the drive waveform W3 shown in Figure 7, the drive circuit 92 applies a suppression voltage drop element D32 to the drive voltage rise element U21 at a timing T32 of n × Tc, and also applies a suppression voltage rise element U22 at a timing T22 of (m - 0.5) × Tc. As a result, the liquid discharge head can cancel out vibrations generated by discharge and suppress residual vibrations generated in the nozzle forming layer. Thus, the drive waveform W3 has a waveform configuration that can suppress residual vibrations generated in the nozzle formation layer.

[0042] (A device for dispensing liquid and a liquid dispensing unit) Next, an example of a liquid dispensing apparatus according to the present invention will be described with reference to Figures 9 and 10. Figure 9 is a plan view illustrating the main parts of the apparatus, and Figure 10 is a side view illustrating the main parts of the apparatus.

[0043] This device is a serial type device, 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.

[0044] The carriage 403 is equipped with a liquid discharge unit 440 that integrates a liquid discharge head 404 and a head tank 441 according to the present invention. The liquid discharge head 404 of the liquid discharge unit 440 discharges liquids of various colors, such as yellow (Y), cyan (C), magenta (M), and black (K). The liquid discharge head 404 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 downwards.

[0045] A supply mechanism 494 for supplying liquid stored outside the liquid discharge head 404 to the liquid discharge head 404 supplies the head tank 441 with liquid stored in the liquid cartridge 450.

[0046] The supply mechanism 494 consists of a cartridge holder 451, which is a filling section for mounting the liquid cartridge 450, a tube 456, a liquid delivery unit 452 including a liquid delivery pump, and the like. The liquid cartridge 450 is detachably mounted in the cartridge holder 451. Liquid is delivered from the liquid cartridge 450 to the head tank 441 via the tube 456 by the liquid delivery unit 452.

[0047] This device includes 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.

[0048] The conveyor belt 412 attracts the paper 410 and transports it to a position opposite the liquid discharge head 404. This conveyor belt 412 is an endless belt and is stretched between the conveyor roller 413 and the tension roller 414. Attraction can be performed by electrostatic attraction or air suction.

[0049] Then, the conveyor belt 412 moves in a circular motion in the sub-scanning direction as the conveyor rollers 413 are rotationally driven by the sub-scanning motor 416 via the timing belt 417 and timing pulley 418.

[0050] Furthermore, a maintenance and recovery mechanism 420 is positioned on one side of the carriage 403 in the main scanning direction, to the side of the conveyor belt 412, for maintaining and recovering the liquid discharge head 404.

[0051] The maintenance and recovery mechanism 420 consists of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzle is formed) of the liquid discharge head 404, and a wiper member 422 that wipes the nozzle surface.

[0052] The main scanning movement mechanism 493, the supply mechanism 494, 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.

[0053] In this configured device, the paper 410 is fed onto the transport belt 412 and picked up, and the paper 410 is transported in the sub-scanning direction by the circumferential movement of the transport belt 412.

[0054] Therefore, by moving the carriage 403 in the main scanning direction and driving the liquid ejection head 404 in accordance with the image signal, liquid is ejected onto the stationary paper 410 to form an image.

[0055] Thus, since this device is equipped with a liquid discharge head according to the present invention, it is possible to stably form high-resolution images.

[0056] Next, an example of a liquid dispensing unit according to the present invention will be described with reference to Figure 11. Figure 11 is a plan view illustrating the main parts of the unit.

[0057] This liquid discharge unit 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 404, which are components of the device that discharges the liquid.

[0058] Furthermore, a liquid dispensing unit can also be configured by further attaching, for example, the side plate 491B of this liquid dispensing unit to at least one of the aforementioned maintenance and recovery mechanism 420 and supply mechanism 494.

[0059] 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 front view of the unit.

[0060] This liquid discharge unit consists of a liquid discharge head 404 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

[0061] 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 connector 443 for electrical connection to the liquid discharge head 404 is provided on the upper part of the flow path component 444.

[0062] In this application, "liquid dispensing device" refers to a device that includes a liquid dispensing head or liquid dispensing unit and drives the liquid dispensing head to dispense liquid. A liquid dispensing device includes not only devices that can dispense liquid onto objects to which liquid can adhere, but also devices that dispense liquid into air or into liquid.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The materials referred to as "materials to which liquid can adhere" above include paper, thread, fibers, fabrics, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing, as long as liquid can adhere to them, even temporarily.

[0068] Furthermore, "liquid" also includes inks, processing solutions, DNA samples, resists, patterning materials, binders, molding fluids, or solutions and dispersions containing amino acids, proteins, calcium, etc.

[0069] 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.

[0070] Other examples of "devices that dispense liquids" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the surface of the paper, and injection granulation devices that granulate fine particles of raw materials by spraying a composition liquid, in which raw materials are dispersed in a solution, through a nozzle.

[0071] A "liquid dispensing unit" is a collection of components related to liquid dispensing, in which functional parts and mechanisms are integrated with a liquid dispensing head. For example, a "liquid dispensing unit" may include a combination of a liquid dispensing head with at least one of the following components: a head tank, carriage, supply mechanism, maintenance and recovery mechanism, and main scanning and moving mechanism.

[0072] 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.

[0073] For example, some liquid dispensing units, such as the liquid dispensing unit 440 shown in Figure 6, 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 by tubes or other means. It is also possible to add a unit containing a filter between the head tank and the liquid dispensing head of these liquid dispensing units.

[0074] Additionally, some liquid dispensing units have an integrated liquid dispensing head and carriage.

[0075] 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. Additionally, as shown in Figure 7, some liquid dispensing units integrate the liquid dispensing head, carriage, and main scanning mechanism.

[0076] 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.

[0077] Furthermore, as shown in Figure 8, some liquid discharge units have a head tank or a liquid discharge head to which a flow path component is attached, to which a tube is connected, integrating the liquid discharge head and the supply mechanism.

[0078] 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.

[0079] Furthermore, the "liquid discharge head" is not limited to any particular pressure generating means. For example, in addition to the piezoelectric actuator described in the above embodiment (which may use a multilayer piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heating resistor, or an electrostatic actuator consisting of a diaphragm and a counter electrode may also be used.

[0080] Furthermore, in the terminology used in this application, image formation, recording, printing, copying, printing, and shaping are all considered synonymous. [Explanation of Symbols]

[0081] 1. Nozzle forming layer 4 nozzles 6 Liquid chamber 92 Drive Circuit 404 Liquid Dispensing Head D12, D32 Lowering element for suppression voltage U11, U21, U31 Drive voltage rise elements U22, U32 Drive voltage rise element W1, W2, W3 drive waveforms W11, W21, W31 1st waveform W12, W22, W32 second waveform [Prior art documents] [Patent Documents]

[0082] [Patent Document 1] Japanese Patent Publication No. 2019-104152

Claims

1. A nozzle forming layer having a piezoelectric layer, A nozzle penetrating the nozzle forming layer, A liquid chamber communicating with the nozzle, The device comprises a drive circuit that applies a drive waveform to drive the piezoelectric layer, If the natural vibration period of the piezoelectric layer is Tc, The drive waveform comprises multiple waveforms that decrease and then increase the voltage, a first waveform having an element that increases the voltage of the drive voltage that applies a drive voltage to discharge the liquid from the liquid chamber from the nozzle, a third waveform that maintains the termination voltage of the element that increases the voltage of the drive voltage, and a second waveform having a voltage reduction element that applies a drive voltage that decreases the voltage from the termination voltage of the element that increases the voltage of the drive voltage at a timing of n × Tc (where n is a positive integer) relative to the start of the element that increases the voltage of the drive voltage. The first waveform, the third waveform, and the second waveform are continuous. The first waveform consists of an element that increases the voltage of the drive voltage, and a waveform element that, prior to the element that increases the voltage of the drive voltage, changes the voltage from the termination voltage of the element that increases the voltage of the drive voltage to the starting voltage of the element that increases the voltage of the drive voltage, and maintains the starting voltage of the element that increases the voltage of the drive voltage. The second waveform consists of the voltage reduction element and, after the voltage reduction element, a waveform element that maintains the termination voltage of the voltage reduction element and then changes the voltage from the termination voltage of the voltage reduction element to the termination voltage of the element that increases the drive voltage. The amplitude of the drive voltage is characterized by being greater than the amplitude of the voltage applied in the second waveform. Liquid dispensing head.

2. A nozzle forming layer having a piezoelectric layer, A nozzle penetrating the nozzle forming layer, A liquid chamber communicating with the nozzle, The device comprises a drive circuit that applies a drive waveform to drive the piezoelectric layer, If the natural vibration period of the piezoelectric layer is Tc, The drive waveform comprises multiple waveforms that decrease the voltage and then increase it, a first waveform having an element that increases the voltage of the drive voltage applied to cause the liquid in the liquid chamber to be discharged from the nozzle, and a second waveform having a voltage-increasing element that applies a drive voltage that increases the voltage at a timing of (m - 0.5) × Tc (where m is a positive integer) relative to the start of the element that increases the voltage of the drive voltage. The termination voltage of the element that increases the voltage of the drive voltage and the termination voltage of the second waveform are the same voltage. The first waveform consists of an element that increases the voltage of the drive voltage, and a waveform element that, prior to the element that increases the voltage of the drive voltage, changes the voltage from the termination voltage of the element that increases the voltage of the drive voltage to the starting voltage of the element that increases the voltage of the drive voltage, and maintains the starting voltage of the element that increases the voltage of the drive voltage. The second waveform consists of the voltage boosting element and a waveform element that, prior to the voltage boosting element, changes the voltage from the termination voltage of the element that increases the drive voltage to the starting voltage of the voltage boosting element, and maintains the starting voltage of the voltage boosting element. The amplitude of the drive voltage is characterized by being greater than the amplitude of the voltage applied in the second waveform. Liquid dispensing head.

3. A nozzle forming layer having a piezoelectric layer, A nozzle penetrating the nozzle forming layer, A liquid chamber communicating with the nozzle, The device comprises a drive circuit that applies a drive waveform to drive the piezoelectric layer, If the natural vibration period of the piezoelectric layer is Tc, The drive waveform comprises multiple waveforms that decrease and then increase the voltage, a first waveform having an element that increases the drive voltage applied to the drive voltage that causes the liquid in the liquid chamber to be discharged from the nozzle, and a second waveform having a voltage-decreasing element that applies a drive voltage that decreases the voltage at a timing of n × Tc (where n is a positive integer) relative to the start of the element that increases the drive voltage, and a voltage-increasing element that applies a drive voltage that increases the voltage at a timing of (m - 0.5) × Tc (where m is a positive integer). The termination voltage of the element that increases the drive voltage, the starting voltage of the second waveform, and the ending voltage of the second waveform are the same voltage. The first waveform consists of an element that increases the voltage of the drive voltage, and a waveform element that, prior to the element that increases the voltage of the drive voltage, changes the voltage from the termination voltage of the element that increases the voltage of the drive voltage to the starting voltage of the element that increases the voltage of the drive voltage, and maintains the starting voltage of the element that increases the voltage of the drive voltage. The second waveform consists of the voltage reduction element, the voltage increase element, and a waveform element between the voltage reduction element and the voltage increase element that maintains the termination voltage of the voltage reduction element, which is changed from the termination voltage of the element that increases the drive voltage. The amplitude of the drive voltage is characterized by being greater than the amplitude of the voltage applied in the second waveform. Liquid dispensing head.

4. The liquid discharge head according to any one of claims 1 to 3, characterized in that the natural vibration period is the natural vibration period of the piezoelectric layer when the liquid chamber and the nozzle are filled with the liquid.

5. The liquid discharge head according to claim 4, characterized in that the first waveform applies pressure to the liquid in the liquid chamber.

6. A liquid dispensing device comprising a liquid dispensing head according to any one of claims 1 to 5.

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