Liquid dispensing head and device for dispensing liquid

Abstract

To provide a liquid discharge head which prevents temperature rise in a refrigerant passage and achieves improvement of cooling efficiency of a common liquid chamber.SOLUTION: A liquid discharge head includes: a piezoelectric actuator (a driving IC 14) including a drive element (a piezoelectric element 22); a liquid chamber member 33 forming an individual liquid chamber 16 communicating with a nozzle 15; a frame member 5 forming a common liquid chamber 19 which supplies a liquid to the individual liquid chamber 16, a refrigerant passage 24 located adjacent to the common liquid chamber 19, and a heat insulation layer 26 disposed between the common liquid chamber 19 and the refrigerant passage 24 and the piezoelectric actuator; a partition plate 23 in which the refrigerant passage 24 is formed by one surface and the heat insulation layer 26 is formed by the other surface; and a heat insulation plate 25 forming the heat insulation layer. The heat insulation layer 26 is filled with a gas or a liquid and has a shape which covers the common liquid chamber 19 and the refrigerant passage 24.SELECTED DRAWING: Figure 4

Description

[[Technical Field]]

[0001] The present invention relates to a liquid discharge head and an apparatus for discharging liquid. [[Background Art]]

[0002] As a structure of a refrigerant flow path used in a liquid discharge head (also referred to as an "inkjet head"), a technique of cooling a common liquid chamber with a refrigerant flow path is already known. For example, Patent Document 1 discloses that heat from a driving IC is blocked or dissipated by forming a gap between the driving IC and a liquid chamber. However, conventional cooling using a refrigerant flow path has a problem in that the performance of insulating heat generated by driving the head is low, and the cooling effect for ink as the liquid is insufficient. [[Brief Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0003] An object of the present invention is to provide a liquid discharge head that prevents a temperature rise of a refrigerant flow path and improves the cooling efficiency of a common liquid chamber. [[Means for Solving the Problem]]

[0004] In order to solve the above-mentioned problem, the liquid discharge head of the present invention comprises: a piezoelectric actuator including a driving element; a liquid chamber member that constitutes individual liquid chambers communicating with nozzles; a frame member that forms a common liquid chamber for supplying liquid to the individual liquid chambers, a refrigerant flow path adjacent to the common liquid chamber, and a heat insulating layer disposed between the common liquid chamber as well as the refrigerant flow path and the piezoelectric actuator; a partition plate that forms the refrigerant flow path on one surface and forms the heat insulating layer on the other surface; and a heat insulating plate that forms the heat insulating layer, wherein the heat insulating layer is filled with gas or liquid and has a shape that covers the common liquid chamber and the refrigerant flow path. [[Effects of the Invention]]

[0005] According to the present invention, it is possible to provide a liquid discharge head that prevents temperature rise in the refrigerant flow path and improves the cooling efficiency of the common liquid chamber. [Brief explanation of the drawing]

[0006] [Figure 1] This figure illustrates the overall configuration of a liquid dispensing head in one embodiment of the present invention. [Figure 2] This diagram illustrates the internal state of the protective cover of the liquid dispensing head shown in Figure 1. [Figure 3] This diagram illustrates the peripheral configuration of the common liquid chamber in the comparative example liquid discharge head. [Figure 4] This figure illustrates the peripheral configuration of the common liquid chamber of the liquid discharge head of the present invention. [Figure 5] This is an example of a liquid dispensing unit with multiple liquid dispensing heads, and shows an example of a cross-section along the VV line in Figure 4. [Figure 6] This figure illustrates a modified example of the heat insulating layer of the liquid dispensing head. [Figure 7] This is a plan view illustrating the main parts of an example of a liquid dispensing device according to the present invention. [Figure 8] This is a side view illustrating the main components of the device. [Modes for carrying out the invention]

[0007] Embodiments of the present invention will be described below with reference to the attached drawings. In each drawing illustrating the embodiments of the present invention, components such as members and parts having the same function or shape will be given the same reference numerals to the extent possible so that they can be identified, and their description will be omitted after they have been described once.

[0008] A liquid discharge head in one embodiment of the present invention supplies liquid from a common liquid chamber to individual liquid chambers communicating with a plurality of nozzles, and discharges the liquid from the nozzles by driving a drive element of a piezoelectric actuator. The liquid discharge head has a structure in which an insulating layer is provided to cover the common liquid chamber and the refrigerant flow path adjacent to the common liquid chamber in case the temperature of the common liquid chamber rises due to the heat of the piezoelectric actuator. The following diagrams will be used to explain this in detail.

[0009] Figure 1 is a diagram illustrating the overall configuration of a liquid dispensing head according to one embodiment of the present invention. Figure 2 illustrates the internal state of the protective cover of the liquid dispensing head shown in Figure 1. The liquid dispensing head 1 comprises at least a protective cover 2, which is an example of a holding member, and a frame member 5.

[0010] Inside the protective cover 2 are the electronic components, a flexible flat cable 3 and a drive IC 14 which acts as a piezoelectric actuator. The driver IC 14 is equipped with a flexible printed circuit board 13 for electronic components, and the DrIC 10 is connected to the flexible printed circuit board 13. Furthermore, a heat dissipation member 4 for dissipating heat generated by the drive IC 14 to the outside, holes 6 for allowing liquid to flow into or out of liquid chambers formed in the frame member 5, a thermistor 11, and a heater 12 are arranged therein.

[0011] Next, we will describe the surrounding configuration of the common liquid chamber of the liquid discharge head 1. Figure 3 illustrates the peripheral configuration of the common liquid chamber in the comparative example's liquid discharge head. Figure 4 illustrates the peripheral configuration of the common liquid chamber of the liquid discharge head of the present invention. Figures 3 and 4 show the surrounding components of the common liquid chamber 19 inside the protective cover 2, including frame members 5 and 5P, drive IC 14, nozzle plate 31, liquid chamber member 33, diaphragm 35, etc.

[0012] The drive IC 14 includes a DrIC 10, a flexible printed circuit board 13, a piezoelectric element 22 as a drive element, and a fixing member 21 that fixes the piezoelectric element 22. A plurality of the piezoelectric elements 22 are provided so as to individually correspond to each of the plurality of nozzles 15. The liquid chamber member 33 forms individual liquid chambers communicating with the nozzles 15. The liquid chamber member 33 is bonded to a nozzle plate 31 on one side and to a vibration plate 35 on the other side. Further, the liquid chamber member 18 has a large-diameter portion 17a and a small-diameter portion 17b as individual supply paths 17 communicating with the individual liquid chambers 16.

[0013] The frame members 5, 5P form a common liquid chamber 19 that supplies liquid to the individual liquid chambers 16 and a refrigerant flow path 24 adjacent to the common liquid chamber 19, and a partition plate 23 forms the refrigerant flow path 24. With this configuration, the liquid discharge heads 1, 1P supply liquid from the common liquid chamber 19 to the individual liquid chambers 16 respectively communicating with the plurality of nozzles 15, and drive the piezoelectric element 22 included in the drive IC 14 to discharge liquid from the nozzles 15.

[0014] Next, the common liquid chamber 19, the refrigerant flow path 24, and the like formed by the frame members 5, 5P will be described. In the configuration around the common liquid chamber of the comparative example, the frame member 5P forms a common liquid chamber 19 that supplies liquid to the individual liquid chambers 16 and a refrigerant flow path 24 adjacent to the common liquid chamber 19, and the partition plate 23 forms the refrigerant flow path 24.

[0015] In order to achieve stable discharge, the liquid discharge head 1P of the comparative example needs to prevent a temperature rise of ink inside the common liquid chamber 19 caused by heat generated by the DrIC 10 and the piezoelectric element 22, and a configuration in which the refrigerant flow path 24 is provided so as to be in contact with the common liquid chamber 19 is used. However, in the configuration shown in FIG. 3, a problem arises in that the cooling effect of the common liquid chamber 19 is insufficient due to the temperature rise of the refrigerant in the refrigerant flow path 24.

[0016] Therefore, the liquid discharge head 1 of the present invention has a modified shape of the frame member 5 and an insulating plate 25 attached to it, thereby forming an insulating layer 26 on the outer circumference of the common liquid chamber 19 and the refrigerant flow path 24.

[0017] In the liquid discharge head 1, the frame member 5 forms a common liquid chamber 19, a refrigerant flow path 24, and a heat insulating layer 26. The frame member 5 is positioned between the common liquid chamber 19 and the refrigerant flow path 24 and the drive IC 14 (piezoelectric actuator), and is formed to cover the common liquid chamber 19 and the refrigerant flow path 24. Furthermore, the partition plate 23 forms a refrigerant flow path 24 on one side and an insulating layer 26 on the other side, and the insulating plate 25 also forms an insulating layer 26. In this configuration, the heat insulating layer 26 has a shape that covers the common liquid chamber 19 and the refrigerant flow path 24, except for the surface of the common liquid chamber 19 that faces the liquid chamber member 33. Furthermore, the insulating layer 26 is filled with gas or liquid.

[0018] In this way, by providing a structure in which an insulating layer 26 has a shape that covers the common liquid chamber 19 and the refrigerant flow path 24, it is possible to prevent the temperature of the refrigerant flow path 24 from rising due to the heat generated by the DrIC 10 and the piezoelectric element 22, and to improve the cooling efficiency of the common liquid chamber 19. This configuration prevents the temperature rise of the ink inside the common liquid chamber 19 compared to the comparative example configuration (Figure 3), thus providing a highly reliable liquid ejection head with fewer ejection failures.

[0019] Next, we will describe the shape of the insulation layer 26. Figure 5 illustrates an example of the shape of the heat insulating layer of the liquid dispensing head according to the present invention. Figure 5 shows an example of a liquid dispensing unit with multiple liquid dispensing heads 1, and illustrates an example of a cross-section along the VV line in Figure 4. Figure 5 shows an example of the shape of the insulating layer 26 that uniformly covers the common liquid chamber 19 and the refrigerant flow path 24.

[0020] Figure 6 illustrates a modified example of the heat insulating layer of the liquid discharge head shown in Figure 5. Figure 6 shows the portion corresponding to area A enclosed by the dashed line in Figure 5. During liquid discharge from the liquid discharge head 1, the heat generated by the DrIC 10 causes a greater temperature rise around the DrIC 10 compared to other areas. The frame member 5A shown in Figure 6 is a modified version of the frame member 5 in Figure 5, forming an insulating layer 26A with a larger area and volume around the DrIC 10 compared to other areas. This prevents a temperature rise in the refrigerant flow path 24 and common liquid chamber 19 around the DrIC 10. This configuration is just one example; the area or volume of the insulation layer in areas where the temperature rise is significant can be changed.

[0021] Furthermore, the gas or liquid filling the insulation layer 26 can be changed to one with low thermal conductivity or high specific heat. Doing so can improve the insulation effect of the heat generated by the drive IC 14. In addition, it is preferable that the insulation layer 26 allows for airflow or liquid flow within it. This would improve cooling efficiency. For example, the gas or liquid may be introduced into or out of a liquid chamber formed in the frame member 5 by providing holes 6 in the heat insulating layer 26 for introducing or out of the liquid. Furthermore, the gas or liquid may be supplied through the holes 6 by blowing or pumping.

[0022] Next, an example of a liquid dispensing apparatus according to the present invention will be described with reference to Figures 7 and 8. Figure 7 is a plan view illustrating the main parts of the apparatus, and Figure 8 is a side view illustrating the main parts of the apparatus.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] Thus, since this device is equipped with a liquid discharge head according to the present invention, it can stably form high-resolution images.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Furthermore, in the terminology used in this application, image formation, recording, printing, copying, printing, and shaping are all considered synonymous.

[0048] Examples of the present invention are as follows: <1> A piezoelectric actuator equipped with a drive element, Liquid chamber members that constitute individual liquid chambers communicating with the nozzle, A frame member forming a common liquid chamber for supplying liquid to the individual liquid chambers, a refrigerant flow path adjacent to the common liquid chamber, and a heat insulating layer disposed between the common liquid chamber, the refrigerant flow path, and the piezoelectric actuator, A partition plate having the refrigerant flow path formed on one side and the heat insulating layer formed on the other side, The system comprises an insulating board that forms the insulating layer, The aforementioned heat insulating layer is a liquid discharge head characterized by being filled with gas or liquid and having a shape that covers the common liquid chamber and the refrigerant flow path. <2> The aforementioned gas or liquid can be changed to one with low thermal conductivity or high specific heat. The aforementioned <1> This is the liquid dispensing head described above. <3> The aforementioned heat insulating layer is characterized by being formed to allow air or liquid to be blown through. <1> or <2> This is the liquid dispensing head described above. <4> The aforementioned heat insulating layer is formed by changing the area or volume of the shape according to the location of the common liquid chamber or the cooling channel. <1> from <3> This is a liquid dispensing head described in one of the following terms. <5> The shape of the heat insulating layer is characterized in that it covers the common liquid chamber and the refrigerant flow path, except for the surface of the common liquid chamber and the refrigerant flow path that faces the liquid chamber member. <1> from <4> This is a liquid dispensing head described in one of the following terms. <6> The aforementioned <1> from <5> This is a liquid dispensing device characterized by having a liquid dispensing head described in any one of the following. [Explanation of symbols]

[0049] 1. Liquid dispensing head 2 Protective cover 3 Flexible flat cable 5, 5A, 5P Frame members 6 holes 13 Flexible Printed Circuit Boards 14. Drive IC (Piezoelectric Actuator) 15 nozzles 16 Individual liquid chambers 19 Common liquid chamber 22 Piezoelectric element (driving element) 23 Partition Plates 24 Refrigerant flow path 25 Insulation board 26, 26A Insulation layer 33 Liquid chamber component [Prior art documents] [Patent Documents]

[0050] [Patent Document 1] Japanese Patent Publication No. 2012-171322

Claims

1. A piezoelectric actuator equipped with a drive element, Liquid chamber members that constitute individual liquid chambers communicating with the nozzle, A frame member forming a common liquid chamber for supplying liquid to the individual liquid chambers, a refrigerant flow path adjacent to the common liquid chamber, and a heat insulating layer disposed between the common liquid chamber, the refrigerant flow path, and the piezoelectric actuator, A partition plate having the refrigerant flow path formed on one side and the heat insulating layer formed on the other side, The system comprises an insulating board that forms the insulating layer, The aforementioned heat insulating layer is filled with gas or liquid and has a shape that covers the common liquid chamber and the refrigerant flow path. A liquid dispensing head characterized by the following features.

2. The aforementioned gas or liquid can be changed to one with low thermal conductivity or high specific heat. The liquid dispensing head according to feature 1.

3. The aforementioned heat insulating layer is formed to allow air or liquid to be blown through it. A liquid dispensing head according to feature 1 or 2.

4. The thermal insulation layer is formed by changing the area or volume of its shape according to the location of the common liquid chamber or the refrigerant flow path. A liquid dispensing head according to feature 1 or 2.

5. The shape of the heat insulating layer covers the common liquid chamber and the refrigerant flow path, except for the surface facing the liquid chamber member between the common liquid chamber and the refrigerant flow path. A liquid dispensing head according to feature 1 or 2.

6. A liquid dispensing device characterized by comprising a liquid dispensing head as described in claim 1 or 2.

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