LIQUID DISCHARGE HEAD, LIQUID DISCHARGE UNIT, AND DEVICE FOR DISCHARGING LIQUID

Abstract

To provide a liquid discharge head capable of suppressing a reduction in piezoelectric performance of a piezoelectric actuator by absorbing moisture from the opening of a circuit connection part.SOLUTION: The liquid discharge head comprises: an oscillation layer 3; a nozzle forming layer 1 that has a piezoelectric actuator 12 and a circuit connection part 90; a liquid chamber forming substrate 2; and a drive circuit 92 that drives the piezoelectric actuator 12. The piezoelectric actuator 12 is formed on the side of the oscillation layer 3 which is near a nozzle 4 and to which a liquid is discharged. The circuit connection part 90 is formed on the side of the oscillation layer 3 to which the liquid is discharged. The drive circuit 92 is formed on a side opposite the circuit connection part 90 with the oscillation layer 3 in between. The nozzle forming layer 1 has a first protection layer 81 which is formed around the circuit connection part 90 and which forms an opening 85 of the circuit connection part 90, a second protection layer 82 formed on the piezoelectric actuator 12, and a water-resistant film 88 formed on the surfaces of the first and second protection layers. The first and second protection layers 81 and 82 are not connected.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, inkjet heads have been known that have a nozzle forming layer having nozzles and a liquid chamber forming substrate that forms liquid chambers. Among such inkjet heads, there are some in which a piezoelectric actuator is formed in the nozzle forming layer.

[0003] In the inkjet head described above, a piezoelectric actuator is formed near the nozzle to eject ink, and a drive circuit for driving the piezoelectric actuator is formed on the liquid chamber forming substrate side. In this case, a connection part is also required to supply power to the drive circuit.

[0004] In Patent Document 1, a piezoelectric actuator is formed in at least a part of the nozzle portion of the nozzle-forming layer, and the piezoelectric actuator is formed on the side of the nozzle-forming layer from which liquid is ejected. A bond pad (also called a circuit connection portion) for passing electricity through a drive circuit that drives the piezoelectric actuator is formed, and the bond pad is formed on the side of the nozzle-forming layer from which liquid is ejected. In addition, a protective layer for protecting the piezoelectric actuator is formed on the side of the nozzle-forming layer from which liquid is ejected, and the protective layer has openings in the areas of the nozzle and the bond pad. Summary of the Invention [Problem to be solved by the invention]

[0005] Polyimide resins, which are commonly used as protective layers in conventional technology, are highly hygroscopic. If moisture is absorbed (water seeps in) through the highly hygroscopic protective layer to the piezoelectric actuator underneath, the performance of the actuator will be reduced. For this reason, it is common to form a waterproof film on the protective layer. However, in the conventional inkjet head manufacturing process, the following steps are usually adopted: forming a piezoelectric actuator film, forming an electrode pad, forming a protective layer film, forming a water-resistant film, and opening a pad opening. Therefore, there is no water-resistant film on the side of the opening formed by the opening of the pad opening. As a result, in the conventional technology, moisture absorption occurs through the opening of the circuit connection, which causes a problem of reduced piezoelectric performance of the piezoelectric actuator. When moisture is absorbed (water seeps in) through the opening of the circuit connection, moisture from the outside air penetrates into the piezoelectric actuator, causing it to deteriorate. In addition, this type of moisture absorption can cause problems such as a shortened lifespan of the inkjet head and reduced reliability.

[0006] Therefore, an object of the present invention is to provide a liquid ejection head in which a piezoelectric actuator and a circuit connection part are formed in a nozzle forming layer, and which can suppress the deterioration of the piezoelectric performance of the piezoelectric actuator due to moisture absorption through the opening of the circuit connection part. [Means for solving the problem]

[0007] In order to solve the above problems, the liquid ejection head of the present invention is a liquid ejection head comprising: a nozzle forming layer having a vibration layer, a piezoelectric actuator, and a circuit connection portion, and in which a nozzle is formed; a liquid chamber forming substrate having a liquid chamber communicating with the nozzle; and a drive circuit connected to the circuit connection portion and driving the piezoelectric actuator, wherein the piezoelectric actuator is formed in the vicinity of the nozzle and on a side of the vibration layer from which liquid is ejected, the circuit connection portion is formed on the side of the vibration layer from which liquid is ejected, and the drive circuit is formed on the opposite side to the circuit connection portion with the vibration layer in between, and the nozzle forming layer has a first protective layer formed around the circuit connection portion and forming an opening of the circuit connection portion, a second protective layer formed on the piezoelectric actuator, and a water-resistant film formed on surfaces of the first protective layer and the second protective layer, and the first protective layer and the second protective layer are not continuous. At the same time, the water-resistant film formed on the surface of the first protective layer and the water-resistant film formed on the surface of the second protective layer are continuous with each other. It is characterized by: Effect of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection head in which a piezoelectric actuator and a circuit connection part are formed in a nozzle forming layer, which can suppress deterioration of the piezoelectric performance of the piezoelectric actuator due to moisture absorption through the opening of the circuit connection part. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing an example of a liquid ejection head according to the present invention. [Diagram 2] 1 is a schematic plan view showing an example of a liquid ejection head according to the present invention. [Diagram 3] FIG. 4 is a schematic cross-sectional view showing another example of a liquid ejection head according to the present invention. [Figure 4A] 1A to 1D are schematic cross-sectional views illustrating an example of a method for manufacturing a liquid ejection head according to the present invention. [Figure 4B] 5A to 5G are schematic cross-sectional views illustrating an example of a method for manufacturing a liquid ejection head according to the present invention. [Figure 4C] 5A to 5J are schematic cross-sectional views illustrating an example of a manufacturing method for a liquid ejection head according to the present invention. [Figure 4D] 5(k) to 5(l) are schematic cross-sectional views illustrating an example of a manufacturing method for a liquid ejection head according to the present invention. [Diagram 5] FIG. 1 is a schematic diagram of an example of a liquid ejection device. [Figure 6] FIG. 11 is a schematic diagram of another example of the liquid ejection device. [Figure 7] FIG. 2 is a schematic diagram of an example of a liquid ejection unit. [Figure 8] FIG. 11 is a schematic diagram of another example of the liquid ejection unit. [Figure 9] FIG. 4 is a schematic cross-sectional view showing a liquid ejection head according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A liquid ejection head, a liquid ejection unit, and a liquid ejection device according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and may be modified within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, deletions, etc., and any aspect is within the scope of the present invention as long as it provides the functions and effects of the present invention.

[0011] The liquid ejection head of the present invention is a liquid ejection head comprising: a nozzle forming layer having a vibration layer, a piezoelectric actuator, and a circuit connection portion, and in which a nozzle is formed; a liquid chamber forming substrate having a liquid chamber communicating with the nozzle; and a drive circuit connected to the circuit connection portion and driving the piezoelectric actuator, wherein the piezoelectric actuator is formed in the vicinity of the nozzle and on the side of the vibration layer from which liquid is ejected, the circuit connection portion is formed on the side of the vibration layer from which liquid is ejected, and the drive circuit is formed on the opposite side of the vibration layer to the circuit connection portion, and the nozzle forming layer has a first protective layer formed around the circuit connection portion and forming an opening of the circuit connection portion, a second protective layer formed on the piezoelectric actuator, and a water-resistant film formed on the surfaces of the first protective layer and the second protective layer, and the first protective layer and the second protective layer are not continuous.

[0012] The liquid ejected by the liquid ejection head of the present embodiment is not particularly limited and can be changed as appropriate. When ejecting ink, the liquid ejection head is also called an inkjet head.

[0013] (First embodiment) The liquid ejection head of this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic cross-sectional view of the liquid ejection head of this embodiment. Figure 2 is a schematic plan view of the liquid ejection head of this embodiment, as viewed from the nozzle surface side (also referred to as the side from which liquid is ejected). Figure 2 is a view viewed from the direction of arrow a in Figure 1, and Figure 1 is a cross-sectional view taken along the line AA in Figure 2.

[0014] As shown in FIG. 1, the liquid ejection head of this embodiment includes a nozzle forming layer 1, a liquid chamber forming substrate 2, and a drive circuit 92.

[0015] The nozzle forming layer 1 has a vibration layer 3, a piezoelectric actuator 12, 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.

[0016] The nozzle forming layer 1 has a nozzle 4, and liquid (e.g., ink) is ejected from the nozzle 4. Liquid in a liquid chamber 6 formed by a part of the nozzle forming layer 1 and the liquid chamber forming substrate 2 is ejected from the nozzle 4 by driving the piezoelectric actuator 12.

[0017] The vibration layer 3 vibrates when driven by the piezoelectric actuator 12. The material of the vibration layer 3 is not particularly limited, but may be, for example, Al2O3, SiN, SiO2, HTO (High Temperature Oxide), or a configuration in which several types of these materials are laminated.

[0018] The liquid chamber forming substrate 2 has a liquid chamber 6 that communicates with the nozzle 4. A circuit protection layer 17 is formed between the liquid chamber forming substrate 2 and the vibration layer 3. The circuit protection layer 17 has the function of protecting the drive circuit 92 and the interlayer wiring layer 95.

[0019] The material of the circuit protection layer 17 is not particularly limited, and examples thereof include PTFE (polytetrafluoroethylene) resins, etc. Furthermore, 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.

[0020] The piezoelectric actuator 12 has a lower electrode 21, a piezoelectric body 22, and an upper electrode 23. The lower electrode 21 may be a common electrode and the upper electrode 23 may be an individual electrode, or the lower electrode 21 may be an individual electrode and the upper electrode 23 may be a common electrode.

[0021] The piezoelectric body 22 is not particularly limited, and may be, for example, PZT (lead zirconate titanate) or the like. The lower electrode 21 and the upper electrode 23 are not particularly limited, and may be made of any known electrode material, such as Pt.

[0022] The piezoelectric actuator 12 or piezoelectric body 22 is formed near the nozzle 4 on the side of the vibration layer 3 from which the liquid is ejected (the nozzle surface side). It may also be stated that the piezoelectric actuator 12 is formed on the vibration layer 3. By forming the piezoelectric actuator 12 in such a location, a vibration plate that applies pressure to the liquid sucked and introduced into the liquid chamber 6 to eject it from the nozzle 4 is not required.

[0023] In the conventional technology not included in the present invention, a nozzle substrate, a liquid chamber forming substrate, and a vibration plate on which a piezoelectric actuator is formed are bonded together in this order, and in this embodiment, the overall structure of the inkjet head can be simplified compared to such conventional technology. Also, according to this embodiment, the manufacturing process of the liquid ejection head can be omitted, and therefore the manufacturing cost can be significantly reduced because the manufacturing process of the vibration plate, the bonding process of the nozzle substrate, the liquid chamber forming substrate, the substrate on which the piezoelectric actuator is formed, and the assembly process can be omitted.

[0024] 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. When there is no need to distinguish between the connection electrodes 94a, 94b, and 94c, they may be referred to as connection electrodes 94.

[0025] 1, a piezoelectric actuator 12a that is not connected to a drive circuit 92 and does not contribute to ejection of liquid may be provided. Such a piezoelectric actuator 12a can be used as a guide for determining the nozzle formation position when forming the nozzle 4, for example.

[0026] The drive circuit 92 is connected to the electrode pad 90, and electricity is applied from a power supply via the electrode pad 90 and the connection electrode 94a. The drive circuit 92 is formed on the opposite side of the vibration layer 3 to the electrode pad 90. Although not limited thereto, the drive circuit 92 is preferably formed on the liquid chamber forming substrate 2. In this case, there is an advantage that the drive circuit 92 can be easily manufactured.

[0027] The driving circuit 92 is not particularly limited, but may be, for example, a CMOS circuit. Also, although not particularly limited, the driving circuit 92 is illustrated as being divided into a portion on the electrode pad 90 side and a portion on the piezoelectric actuator 12 side, and these portions are connected by an interlayer wiring layer 95. The interlayer wiring layer 95 may be made of, for example, a known electrode material.

[0028] The electrode pad 90 (circuit connection portion) is formed on the side of the vibration layer 3 from which the liquid is ejected (the nozzle surface side), and is connected to the drive circuit 92 via a connection electrode 94a. Here, two connection electrodes 94a are illustrated, but the present invention is not limited to this. The two connection electrodes 94a are illustrated in consideration of the two connection electrodes 94b, 94c corresponding to the lower electrode 21 and upper electrode 23 of the piezoelectric actuator 12.

[0029] As shown in the figure, in this embodiment, protective layers 81 and 82 are formed on the side from which liquid is ejected (nozzle surface side). The first protective layer 81 is formed around the electrode pad 90 and forms an opening 85 in 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, for example, at least one of the piezoelectric actuator 12, the vibration layer 3, and the electrode pad 90 can be protected, and deterioration of the members can be prevented.

[0030] The material of the first protective layer 81 and the second protective layer 82 is not particularly limited, and for example, a polyimide resin or the like can be used. The first protective layer 81 and the second protective layer 82 may be made of the same material or different materials. From the viewpoint of ease of manufacture, it is preferable that they are made of the same material. The location where the first protective layer 81 and the second protective layer 82 are formed is not particularly limited, and it is preferable that they are formed on the entire surface or almost the entire surface of the nozzle forming layer 1.

[0031] As shown in the figure, the first protective layer 81 is formed around the electrode pad 90, forming an opening 85 of the electrode pad 90. In the example shown in the figure, the first protective layer 81 and the electrode pad 90 are spaced apart, but the first protective layer 81 and the electrode pad 90 may be in contact with each other. In addition, the periphery of the electrode pad 90 is not limited to a shape that surrounds all four sides as shown in FIG. 2. For example, there may be some parts that are spaced apart.

[0032] As shown in the figure, the second protective layer 82 is formed on the piezoelectric actuator 12, and is opened corresponding to the opening of the vibration layer 3 to form a nozzle 4. The opening of the vibration layer 3 may be referred to as the nozzle 4, or the opening of the vibration layer 3 and the second protective layer 82 may be referred to as the nozzle 4.

[0033] The liquid ejection 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, it is possible to more effectively block the penetration of water, and it is possible to more effectively suppress the problem of the performance of the piezoelectric actuator 12 deteriorating due to the influence of moisture penetrating through the protective layers. This makes it possible to further improve the life span of the liquid ejection head, and further improve the reliability.

[0034] The water-resistant film 88 may be made of, for example, Al2O3, TaO2, or AlN. In addition, the water-resistant film 88 is not shown in FIG.

[0035] 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 portion 86 and are discontinuous. By doing so, in a liquid ejection head in which a piezoelectric actuator 12 and an electrode pad 90 (circuit connection portion) are formed on the nozzle forming layer 1, it is possible to suppress a decrease in the piezoelectric performance of the piezoelectric actuator 12 due to moisture absorption from the opening portion 85 of the electrode pad 90.

[0036] In the conventional technology, there was a problem that moisture absorption occurs from the opening of the electrode pad, which reduces the piezoelectric performance of the piezoelectric actuator. When moisture is absorbed (water seeps in) from the opening of the electrode pad, moisture from the outside air penetrates into the piezoelectric actuator, causing it to deteriorate. In addition, such moisture absorption can cause problems such as a shortened lifespan of the inkjet head and a decrease in reliability.

[0037] Here, a comparative example that is not included in the present invention will be described with reference to FIG. 9. The comparative example is an example in which a water-resistant film 88 is formed on the surface of the protective layer 83. In this comparative example, the water-resistant film 88 is not formed on the inside (also referred to as the side of the opening) of the electrode pad, and the protective layer 83 comes into contact with the outside air in the portion where the water-resistant film 88 is not formed. Therefore, moisture absorption occurs from the protective layer 83 in this portion, and moisture from the outside air reaches the piezoelectric actuator 12 through the protective layer 83. To explain this, it is shown typically by the white arrow in the figure. This causes the piezoelectric actuator to deteriorate.

[0038] In contrast, in this embodiment, since the first protective layer 81 and the second protective layer 82 are not continuous, even if moisture from the outside air seeps in through the opening 85 without the water-resistant film 88, the moisture can be prevented from corroding the piezoelectric actuator 12. If the first protective layer 81 and the second protective layer 82 are continuous, for example, if the separation groove portion 86 is not provided, moisture will penetrate between the protective layers 81 and 82 and the vibration layer 3 from the opening 85 and reach the piezoelectric actuator 12. On the other hand, since the first protective layer 81 and the second protective layer 82 are not continuous, even if moisture seeps in between the first protective layer 81 and the vibration layer 3 from the opening 85, it will only reach the separation groove portion 86. Therefore, it is possible to prevent the piezoelectric actuator 12 from being affected.

[0039] In this embodiment, a separation groove portion 86 is formed, but since the surface of the protective layer covering the piezoelectric actuator is covered with a water-resistant film 88, the penetration of moisture from the separation groove portion 86 between the second protective layer 82 and the vibration layer 3 can be prevented.

[0040] The location where the water-resistant film 88 is formed can be changed as appropriate, but as shown in the figure, it is preferable that the water-resistant film formed on the surface of the first protective layer 81 and the water-resistant film formed on the surface of the second protective layer 82 are continuous. This can further inhibit the intrusion of moisture from, for example, the separation groove portion 86, and can further block the penetration of water.

[0041] Second embodiment Next, a liquid ejection head according to another embodiment of the present invention will be described, and a description of the same matters as those in the above embodiment will be omitted.

[0042] The liquid ejection head of this embodiment is shown in Fig. 3. Fig. 3 is a schematic cross-sectional view similar to Fig. 1. In the liquid ejection head of this embodiment, the liquid chamber forming substrate is a SOI (Silicon on Insulator) substrate. In this embodiment, the SOI substrate has an insulating layer 89 on the drive circuit 92 side.

[0043] According to this embodiment, by using an SOI substrate for the liquid chamber forming substrate 2, and in particular by having the insulating layer 89 on the drive circuit 92 side of the SOI substrate, it is possible to reduce stray capacitance and leakage current occurring in the drive circuit 92. This makes it possible to increase the speed and reduce power consumption of the printing process using the liquid ejection head of this embodiment, and also improve the voltage resistance and reliability of the drive circuit.

[0044] In the conventional drive circuit configuration, stray capacitance and leakage current occur from the drive circuit, causing signal delays and leakage current to the substrate. In this embodiment, such problems can be prevented.

[0045] It is also preferable that the present embodiment has the above-mentioned water-resistant film 88, in which case reliability and the like can be further improved.

[0046] (Manufacturing method) Next, a method for manufacturing the liquid ejection head in the first embodiment will be described with reference to Figures 4A to 4D, which are schematic cross-sectional views similar to those described above. Here, an example in which a normal silicon substrate is used will be described, but the manufacturing method will basically follow the same flow even when the SOI substrate in the third embodiment is used.

[0047] First, a CMOS circuit that serves as the drive circuit 92 and an interlayer wiring layer 95 that connects the drive circuit 92 to the piezoelectric actuator are formed on a silicon substrate prepared as a liquid chamber forming substrate 2 using conventional techniques (Figures 4A (a) and (b)).

[0048] Next, a circuit protection layer 17 is formed to protect the drive circuit 92 and the interlayer wiring layer 95. Furthermore, the vibration layer 3 is formed on the circuit protection layer 17 (FIG. 4A(c)). As a material for the circuit protection layer 17, for example, a PTFE-based resin is used, and as a material for the vibration layer 3, for example, Al2O3, SiN, SiO2, HTO, or a configuration in which several types of these materials are laminated is used.

[0049] Next, a contact portion (connection electrode 94a) that connects the drive circuit 92 to the electrode pad, and contact portions (connection electrodes 94b, 94c) that connect the drive circuit 92 to the piezoelectric actuator are formed (FIG. 4A(d)).

[0050] Next, the lower electrode 21 is formed on the vibration layer 3 using Pt (FIG. 4B(e)). The lower electrode 21 can be formed into a film pattern by photolithography and etching. As shown in the figure, an electrode pad 90 is formed as a circuit connection part that supplies power to a drive circuit 92. Furthermore, as shown in the figure, after masking, a piezoelectric material that becomes the piezoelectric body 22 is formed into a film by a process such as CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition), and then the mask is removed. As the piezoelectric material, various materials including PZT can be selected.

[0051] Next, a mask for wiring is applied, and the mask is removed after the electrode material is deposited. This makes it possible to ensure electrical continuity between the upper electrode 23 and the connection electrode 94c at the same time as the deposition of the upper electrode 23 (FIG. 4B(f)).

[0052] Next, protective layers 81, 82 are formed on the upper surfaces of the piezoelectric actuators 12, 12a formed to surround the position where the nozzle is formed, and the electrode pad 90 (FIG. 4B(g)). In this example, the protective layer is formed on the entire upper surface of the nozzle formation layer, but this is not limited to this. Also, in this example, the first protective layer and the second protective layer are made of the same material (e.g., polyimide resin), so they are illustrated here as protective layers 81, 82.

[0053] Next, photolithography and etching are performed from the back side (the side opposite to the piezoelectric actuator 12, etc.) of the liquid chamber forming substrate 2 to form the liquid chamber 6 (FIG. 4C(h)). At this time, the vibration layer 3 plays the role of an etch stop.

[0054] Next, photolithography is performed on the protective layers 81 and 82 formed on the entire upper surface of the nozzle formation layer to form a nozzle groove 4a (FIG. 4C(i)). In this way, the protective layer is opened in accordance with the shape of the nozzle portion at the nozzle formation position surrounded by the piezoelectric actuator. Also, as shown in the figure, a separation groove 86 is formed to separate the first protective layer and the second protective layer.

[0055] Next, the nozzle formation layer is etched using the protective layer opened by the above-mentioned photolithography as a mask to form the nozzle 4 (FIG. 4C(j)). At this time, the vibration layer 3 in the groove (separation groove 86) around the formed electrode pad 90 is also etched at the same time, but the drive circuit 92 is protected by the circuit protection layer 17 below the vibration layer 3.

[0056] Next, the water-resistant film 88 is formed from the nozzle surface side (FIG. 4D(k)). The water-resistant film 88 is formed on the surfaces of the protective layers 81 and 82 by a method such as ALD (Atomic Layer Deposition).

[0057] Next, masking is performed to open the electrode pad portion to form the opening 85 (FIG. 4D(l)). In this way, the liquid ejection head of this embodiment is obtained.

[0058] Thereafter, by combining it with a separately manufactured component such as a common liquid chamber substrate, a liquid ejection head having a common liquid chamber can be manufactured. Other components may also be used as necessary.

[0059] According to the manufacturing method of this embodiment, the manufacturing process of the liquid ejection head can eliminate the steps of manufacturing the vibration plate, and the steps of bonding and assembling the nozzle substrate, the liquid chamber forming substrate, the substrate on which the piezoelectric actuator is formed, and the frame substrate, thereby significantly reducing manufacturing costs.

[0060] (Liquid ejection device and liquid ejection unit) Next, an example of a liquid ejecting device according to the present invention will be described with reference to Figures 5 and 6. Figure 5 is a plan view of the main part of the device, and Figure 6 is a side view of the main part of the device.

[0061] This device is a serial type device, and a carriage 403 is reciprocated in the main scanning direction by a main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is hung between left and right side plates 491A and 491B to movably hold the carriage 403. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

[0062] A liquid ejection unit 440, which integrates a liquid ejection head 404 according to the present invention and a head tank 441, is mounted on this carriage 403. The liquid ejection head 404 of the liquid ejection unit 440 ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid ejection head 404 is mounted with a nozzle row made up of a plurality of nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward.

[0063] A supply mechanism 494 for supplying liquid stored outside the liquid ejection head 404 to the liquid ejection head 404 supplies the liquid stored in the liquid cartridge 450 to the head tank 441 .

[0064] The supply mechanism 494 is composed of a cartridge holder 451 which is a filling section to which a liquid cartridge 450 is attached, a tube 456, a liquid delivery unit 452 including a liquid delivery pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. The liquid is delivered from the liquid cartridge 450 to the head tank 441 by the liquid delivery unit 452 via the tube 456.

[0065] This device 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.

[0066] The conveyor belt 412 attracts the paper 410 and conveys it to a position facing the liquid ejection head 404. The conveyor belt 412 is an endless belt, and is stretched between a conveyor roller 413 and a tension roller 414. The paper can be attracted by electrostatic attraction or air suction.

[0067] The conveyor belt 412 moves in a circular motion in the sub-scanning direction as the conveyor rollers 413 are rotated by a sub-scanning motor 416 via a timing belt 417 and a timing pulley 418 .

[0068] Furthermore, a maintenance and recovery mechanism 420 for performing maintenance and recovery of the liquid ejection head 404 is disposed on one side of the conveyor belt 412 on one side of the carriage 403 in the main scanning direction.

[0069] The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface (surface on which nozzles are formed) of the liquid ejection head 404, a wiper member 422 that wipes the nozzle surface, and the like.

[0070] The main scanning movement mechanism 493, the supply mechanism 494, the maintenance and recovery mechanism 420, and the transport mechanism 495 are attached to a housing including side plates 491A and 491B and a back plate 491C.

[0071] In the device thus configured, a sheet of paper 410 is fed onto and adsorbed to the conveyor belt 412, and the sheet of paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412.

[0072] Thus, by driving a liquid ejection head 404 in response to an image signal while moving a carriage 403 in the main scanning direction, liquid is ejected onto a stationary paper 410 to form an image.

[0073] In this manner, since this device is equipped with the liquid ejection head according to the present invention, it is possible to stably form high quality images.

[0074] Next, another example of the liquid ejection unit according to the present invention will be described with reference to Fig. 7. Fig. 7 is a plan view illustrating the main parts of the unit.

[0075] This liquid ejection unit is composed of a housing portion consisting of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 404, among the components that make up the device that ejects the liquid.

[0076] It should be noted that a liquid discharge unit can also be configured in which at least one of the above-mentioned maintenance and recovery mechanism 420 and supply mechanism 494 is further attached to, for example, side plate 491B of this liquid discharge unit.

[0077] Next, still another example of a liquid discharge unit according to the present invention will be described with reference to Fig. 8. Fig. 8 is a front explanatory view of the unit.

[0078] This liquid discharge unit is composed of a liquid discharge head 404 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444 .

[0079] The flow path part 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path part 444. A connector 443 for electrically connecting with the liquid ejection head 404 is provided on the upper part of the flow path part 444.

[0080] In this application, a "liquid ejection device" is a device that includes a liquid ejection head or a liquid ejection unit and ejects liquid by driving the liquid ejection head. A liquid ejection device includes not only a device that can eject liquid onto an object onto which the liquid can adhere, but also a device that ejects liquid into air or liquid.

[0081] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0082] For example, examples of "devices that eject liquid" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0083] In addition, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0084] The above-mentioned "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, cloth, and other recording media, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

[0085] The material of the above-mentioned "object to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing.

[0086] The term "liquid" also includes ink, processing liquid, DNA sample, resist, pattern material, binder, modeling liquid, or solutions and dispersions containing amino acids, proteins, or calcium.

[0087] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, a line type device in which a liquid ejection head does not move, etc.

[0088] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0089] A "liquid ejection unit" is a collection of components related to ejecting liquid, in which functional parts and mechanisms are integrated with a liquid ejection head. For example, a "liquid ejection unit" includes a combination of a liquid ejection head and at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism.

[0090] Here, integration includes, for example, a liquid ejection head, a functional part, and a mechanism that are fixed to each other by fastening, bonding, engaging, etc., and one is held movably relative to the other. Also, the liquid ejection head, the functional part, and the mechanism may be configured to be detachable from each other.

[0091] For example, there are liquid ejection units in which the liquid ejection head and the head tank are integrated, such as liquid ejection unit 440 shown in Fig. 6. There are also liquid ejection units in which the liquid ejection head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

[0092] Furthermore, there is a liquid ejection unit in which the liquid ejection head and the carriage are integrated.

[0093] In addition, there is a liquid ejection unit in which the liquid ejection head is movably held by a guide member constituting a part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated together. In addition, as shown in Fig. 7, there is a liquid ejection unit in which the liquid ejection head, the carriage, and the main scanning movement mechanism are integrated together.

[0094] Furthermore, there is a liquid ejection unit in which a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which the liquid ejection head is attached, thereby integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

[0095] As another liquid ejection unit, as shown in FIG. 8, there is a liquid ejection head having a head tank or a flow path part attached thereto and a tube is connected to the liquid ejection head, and the liquid ejection head and a supply mechanism are integrated together.

[0096] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0097] Furthermore, the pressure generating means used in the "liquid ejection head" is not limited. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, or an electrostatic actuator consisting of a vibration plate and an opposing electrode may be used.

[0098] In addition, in the present application, the terms image formation, recording, printing, imprinting, printing, modeling, and the like are all synonymous. [Explanation of symbols]

[0099] 1 Nozzle forming layer 3 vibration layer 4 Nozzles 6 Liquid chamber 12 Piezoelectric Actuator 17 Circuit protection layer 21 Lower electrode 22 Piezoelectric 23 Upper electrode 81 First protective layer 82 Second Layer of Protection 85 Opening 86 Separation groove 88 Waterproof membrane 89 Insulating Layer 90 Electrode Pads 92 Drive circuit 94 Connection electrode 95 Interlayer Wiring [Prior art documents] [Patent documents]

[0100] [Patent Document 1] Special Publication No. 2019-530601

Claims

1. a nozzle forming layer having a vibration layer, a piezoelectric actuator, and a circuit connection portion, and in which a nozzle is formed; a liquid chamber forming substrate having a liquid chamber communicating with the nozzle; a drive circuit connected to the circuit connection portion and configured to drive the piezoelectric actuator, the piezoelectric actuator is formed in the vicinity of the nozzle on a side of the vibration layer from which liquid is ejected, the circuit connection portion is formed on the side of the vibration layer from which liquid is ejected, the drive circuit is formed on the opposite side of the vibration layer from the circuit connection portion, the nozzle formation layer has a first protective layer formed around the circuit connection portion and forming an opening of the circuit connection portion, a second protective layer formed on the piezoelectric actuator, and a water-resistant film formed on surfaces of the first protective layer and the second protective layer, The first protective layer and the second protective layer are not continuous, A liquid ejection head, characterized in that the water-resistant film formed on the surface of the first protective layer and the water-resistant film formed on the surface of the second protective layer are continuous with each other.

2. 2. The liquid ejection head according to claim 1, wherein the liquid chamber forming substrate is an SOI (Silicon on Insulator) substrate.

3. 3. The liquid ejection head according to claim 2, wherein the SOI substrate has an insulating layer on the side of the drive circuit.

4. a nozzle forming layer having a vibration layer, a piezoelectric actuator, and a circuit connection portion, and in which a nozzle is formed; a liquid chamber forming substrate having a liquid chamber communicating with the nozzle; a drive circuit connected to the circuit connection portion and configured to drive the piezoelectric actuator, the piezoelectric actuator is formed in the vicinity of the nozzle on a side of the vibration layer from which liquid is ejected, the circuit connection portion is formed on the side of the vibration layer from which liquid is ejected, the drive circuit is formed on the opposite side of the vibration layer from the circuit connection portion, the nozzle formation layer has a first protective layer formed around the circuit connection portion and forming an opening of the circuit connection portion, a second protective layer formed on the piezoelectric actuator, and a water-resistant film formed on surfaces of the first protective layer and the second protective layer, The first protective layer and the second protective layer are not continuous, the liquid chamber forming substrate is an SOI (Silicon on Insulator) substrate, The liquid ejection head according to the present invention, wherein the SOI substrate has an insulating layer on the side of the driving circuit.

5. 5. The liquid ejection head according to claim 4, wherein the water-resistant film formed on the surface of the first protective layer and the water-resistant film formed on the surface of the second protective layer are continuous with each other.

6. 6. The liquid ejection head according to claim 1, wherein the drive circuit is formed on the liquid chamber forming substrate.

7. A liquid ejection unit comprising the liquid ejection head according to any one of claims 1 to 6.

8. The liquid ejection unit according to claim 7, characterized in that the liquid ejection head is integrated with at least one of a head tank that stores liquid to be supplied to the liquid ejection head, a carriage that mounts the liquid ejection head, a supply mechanism that supplies liquid to the liquid ejection head, a maintenance and recovery mechanism that maintains and recovers the liquid ejection head, and a main scanning movement mechanism that moves the liquid ejection head in a main scanning direction.

9. 9. A liquid ejection device comprising: a liquid ejection head according to claim 1; or a liquid ejection unit according to claim 7 or 8.

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