JP7679609B2 - Manufacturing method of liquid ejection head and manufacturing method of liquid ejection device - Google Patents

Description

The present invention relates to a method for manufacturing a liquid ejection head and a method for manufacturing a liquid ejection device.

A liquid ejection head that uses a piezoelectric material is known that ejects ink by vibrating the nozzle surface. It is known that such liquid ejection heads require large vibrations to eject ink.

Patent document 1 discloses a head structure in which nozzle holes that penetrate a nozzle substrate plate and a piezoelectric thin film are provided. This makes it possible to increase the ink droplet ejection energy, and thus achieve stable ink ejection.

Patent Document 2 also discloses that the nozzle part of the vibration substrate is vibrated to generate standing waves near the surface of the liquid ink held in the nozzle toward the center of the nozzle, causing droplets to fly from the ink surface at the center of the nozzle. This is said to be highly energy efficient and capable of ejecting small droplets. Patent Document 1 also discloses an embodiment in which two substrates are bonded together to form a nozzle that penetrates both substrates, and droplets are ejected by vibrating the substrate around the nozzle.

However, conventional technology has not yet been able to ensure sufficient vibration. In order to ensure sufficient vibration, it is conceivable to attempt to increase the piezoelectric constant of the piezoelectric material by, for example, depositing the piezoelectric material at a high temperature, thereby obtaining a large displacement.

However, when the current manufacturing methods for thin-film piezoelectric materials are applied to liquid ejection heads that eject ink by vibrating the nozzle surface, the substrate warps due to excessive temperature and other reasons. If nozzle holes are formed on a substrate in a warped state, there is a problem in that the nozzle shape within the substrate varies, resulting in variations in the ejection characteristics.

The present invention aims to suppress variation in ejection characteristics in a liquid ejection head that ejects liquid by vibrating the nozzle plate.

In order to solve the above problems, the manufacturing method of a liquid ejection head of the present invention is a manufacturing method of a liquid ejection head in which liquid is ejected by vibration of a nozzle plate having a substrate and a piezoelectric body, and includes a piezoelectric body formation process in which the piezoelectric body is deposited on the substrate at 450°C to 600°C, and a nozzle hole formation process in which a nozzle hole penetrating the substrate and the piezoelectric body is formed, characterized in that the piezoelectric body formation process forms the piezoelectric body by a sputtering method or a CVD (Chemical Vapor Deposition) method .

According to the present invention, it is possible to suppress variation in ejection characteristics in a liquid ejection head that ejects liquid by vibrating the nozzle plate.

1 is a schematic cross-sectional view of an example of a liquid ejection head according to the present invention. 1 is a schematic cross-sectional view of a main portion of an example of a liquid ejection head according to the present invention. 1 is a schematic exploded perspective view of a main portion of an example of a liquid ejection head according to the present invention. 1 is an exploded perspective schematic view of an example of a liquid ejection head according to the present invention. FIG. 4 is a schematic cross-sectional view of a liquid ejection head according to a comparative example. FIG. 4 is a schematic cross-sectional view of a main part of a liquid ejection head according to a comparative example. FIG. 2 is a schematic cross-sectional view of an example of a liquid ejection head. FIG. 11 is a schematic cross-sectional view of another example of a liquid ejection head. FIG. 11 is a schematic cross-sectional view of another example of a liquid ejection head. FIG. 11 is a schematic perspective view of another example of a liquid ejection head. FIG. 1 is a schematic diagram of an example of a liquid ejection device. FIG. 2 is a schematic diagram of an example of a head unit. FIG. 1 is a block diagram illustrating an example of a liquid circulation device. FIG. 11 is a schematic diagram of another example of the liquid ejection device. FIG. 11 is a schematic diagram of another example of the liquid ejection device. FIG. 2 is a schematic diagram of an example of a liquid ejection unit. FIG. 11 is a schematic diagram of another example of the liquid ejection unit.

The manufacturing method of the liquid ejection head and the manufacturing method of the 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 embodiments shown below, and can 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 achieves the functions and effects of the present invention.

The manufacturing method of the liquid ejection head of this embodiment is a manufacturing method of a liquid ejection head that ejects liquid by vibrating a nozzle plate having a substrate and a piezoelectric body, and is characterized by including a piezoelectric body forming process in which the piezoelectric body is formed on the substrate at 450°C to 600°C, and a nozzle hole forming process in which a nozzle hole penetrating the substrate and the piezoelectric body is formed.

Figure 1 is a schematic cross-sectional view illustrating an example of a liquid ejection head obtained by this embodiment. In Figure 1, a nozzle plate 1, a nozzle hole 4, a substrate 81, a piezoelectric body 82, a common liquid chamber plate 83, a common liquid chamber 84, a partition wall 85, a ceiling plate 86, and a supply channel 87 are shown. Note that the figure shows only the essential parts in order to explain the liquid ejection head of this embodiment, and other components may be provided as necessary.

Liquid (e.g., ink) passes through a supply path 87 provided in a ceiling plate 86 and is supplied to a common liquid chamber 84 provided in a common liquid chamber plate 83 (common liquid chamber substrate). The ceiling plate 86 can be made of, for example, a metal material, and the common liquid chamber plate 83 can be made of, for example, Si.

The nozzle plate 1 has a substrate 81 and a piezoelectric body 82 provided on the side of the object to be discharged. When the nozzle plate 1 vibrates, liquid in a common liquid chamber 84 is discharged from the nozzle holes 4. The number, arrangement, and shape of the nozzle holes 4 can be changed as appropriate, but the nozzle holes 4 are formed to penetrate the substrate 81 and the piezoelectric body 82.

The nozzle plate 1 may be provided with electrodes so that the nozzle plate 1 vibrates to eject liquid. Known materials can be used for the electrodes.

Next, a method for manufacturing the liquid ejection head of this embodiment will be described.
2 is a diagram for explaining the process of forming the nozzle plate 1, and is a schematic cross-sectional view of the nozzle plate 1. In FIG. 2, a piezoelectric body forming process and a nozzle hole forming process are performed.

2A shows a substrate 81. The substrate 81 can be changed as appropriate, but for example, a Si substrate can be used. When the substrate 81 is a Si substrate, an oxide film such as _SiO2 may be formed. The thickness of the substrate 81 is preferably, for example, 200 μm to 900 μm.

Figure 2 (B) is a diagram for explaining the piezoelectric body formation process, in which a piezoelectric body 82 is formed on a substrate 81. The piezoelectric body 82 is preferably made of PZT (lead zirconate titanate). The thickness of the piezoelectric body 82 is preferably, for example, 1 μm to 6 μm.

In the piezoelectric body formation process, the temperature (film formation temperature ) at which the piezoelectric body is formed is 450°C to 600°C. By keeping the temperature within this range, it is possible to prevent the substrate 81 from warping when the piezoelectric body is formed. If the film formation temperature is higher than 600°C, the temperature becomes too high and the substrate 81 warps, causing problems such as variations in the shape of the nozzle holes formed in a later process within the liquid ejection head. If the film formation temperature is lower than 450°C, the piezoelectric body is not sufficiently formed, and sufficient ejection characteristics cannot be obtained.

The film formation temperature is preferably 450°C to 550°C. In this case, warping of the substrate 81 can be further suppressed. This can further suppress variation in the ejection characteristics within the liquid ejection head.

The piezoelectric body 82 can be formed by, for example, a sputtering method, a CVD (Chemical Vapor Deposition) method, a sol-gel method, or the like. In the sol-gel method, a precursor solution of the piezoelectric body is applied onto the substrate 81, and then the substrate and the precursor solution of the piezoelectric body are heated to the above-mentioned film formation temperature.

Figure 2(C) is a diagram for explaining the nozzle hole forming process, in which the nozzle hole 4 is formed penetrating the substrate 81 and the piezoelectric body 82. The method for forming the nozzle hole 4 can be changed as appropriate, but for example, dry etching can be used.

The manufacturing method for the liquid ejection head of this embodiment can prevent the substrate from warping when forming the piezoelectric body. This can suppress variation in the nozzle shape within the liquid ejection head. For example, it can prevent the nozzle holes near the center of the nozzle plate 1 from having different shapes from the nozzle holes on the end sides. In addition, it can prevent the nozzle holes on one end side of the nozzle plate 1 from having different shapes from the nozzle holes on the other end side.

This makes it possible to suppress variation within the liquid ejection head in ejection characteristics such as the amount of liquid droplets ejected from each nozzle, droplet speed (velocity of droplets), and landing position accuracy. This further improves image quality.

FIG. 3 is a schematic cross-sectional view of the nozzle plate 1 in this embodiment.
FIG. 3A is a schematic diagram showing a state in which nozzle holes 4 are formed in a nozzle plate 1. As shown in FIG.
Since it is possible to prevent the substrate 81 from warping, it is possible to align the heights of the left and right nozzle holes 4. For example, as shown in the figure, it is possible to align the heights of the nozzle surfaces 1b and 1c near the nozzle holes 4. This also makes it possible to align the shapes of the nozzle holes in the liquid ejection head.

Figure 3 (B) is a schematic diagram showing an example in which liquid 88 flows through nozzle hole 4 and liquid 88 accumulates in nozzle hole 4. Since nozzle surface 1b and nozzle surface 1c are aligned near nozzle hole 4, the shape of the meniscus can be made the same on both sides of the central axis of nozzle hole 4. In addition, the shape of the meniscus can be made uniform between nozzle holes within the liquid ejection head.

Figure 3(C) is a diagram that shows a schematic example of a case where liquid 88 is ejected from the nozzle hole 4, and the arrow shows a schematic direction in which the liquid 88 is ejected. The liquid 88 can be ejected straight from the nozzle hole 4. In addition, it is possible to suppress variation in the ejection direction between the nozzle holes 4 within the liquid ejection head.

Here, we will explain a liquid ejection head in a comparative example, which will be described later. Figure 5 is a schematic cross-sectional view of a liquid ejection head in the comparative example. In the comparative example, the piezoelectric body 82a is formed at a temperature higher than the film formation temperature in this embodiment, for example, at a temperature exceeding 600°C but not exceeding 800°C, so that the substrate 81a becomes warped, and the nozzle plate 1a also becomes warped.

If the nozzle holes 4a are formed in this state, the heights of the left and right sides of the nozzle holes will differ. In addition, the nozzle shape and the volume inside the nozzles will differ for each nozzle. This causes the ejection characteristics to vary within the liquid ejection head.

In order to explain the above in detail, an enlarged schematic cross-sectional view of the portion enclosed by the broken line in FIG. 5 is shown in FIG.
6A, because the nozzle hole 4a is formed in the nozzle plate 1a having a warped shape, the height of the nozzle hole differs between the left and right sides. For example, the figure shows that the nozzle surface 1b and the nozzle surface 1c are at different heights.

When liquid is supplied to the nozzle hole 4a in this state, the height of the meniscus will differ between the left and right sides, as shown in Figure 6 (B). In addition, the shape of the nozzle and the volume inside the nozzle will differ for each nozzle.

In this case, as shown in FIG. 6C, not only does the ejection bend occur, but the amount of ejection bend varies from nozzle to nozzle. In addition, the amount of liquid droplets ejected from each nozzle, the droplet speed (velocity of the droplets), and the landing position accuracy also vary from nozzle to nozzle, causing the ejection characteristics to vary within the liquid ejection head. This causes problems such as failure to obtain good quality images.

Next, the bonding process and other steps in the manufacturing method of the liquid ejection head of this embodiment will be described. Figure 4 is an exploded perspective view for explaining this embodiment.

Figure 4 (A) is a schematic perspective view of a ceiling plate 86. A supply path 87 is formed in the ceiling plate 86. Figure 4 (B) is a schematic perspective view of a common liquid chamber plate 83 (common liquid chamber substrate). A common liquid chamber 84 is formed in the common liquid chamber plate 83. Figure 4 (C) is a schematic perspective view of a nozzle plate 1, which is the nozzle plate 1 obtained according to Figure 3.

By joining the components shown in FIG. 4 together, the liquid ejection head of this embodiment shown in FIG. 1 can be obtained. In the joining process of this embodiment, after the nozzle hole forming process, the ceiling plate 86 is joined to the substrate 81 side of the nozzle plate 1.

Furthermore, according to this embodiment, a method for manufacturing a liquid ejection head is provided. The method for manufacturing a liquid ejection device of this embodiment is a method for manufacturing a liquid ejection device using the method for manufacturing a liquid ejection head of this embodiment.

(Example 1 and Comparative Example 1)
2 to 4, the liquid ejection head shown in Fig. 1 is manufactured. First, a 10 μm thick SiO ₂ film is formed on a Si substrate, which serves as a substrate 81.
Next, a PZT film having a thickness of 10 μm was formed on the SiO ₂ film of the substrate 81 by sputtering at a film formation temperature of 550° C. to form a piezoelectric body 82. In this way, the nozzle plate 1 was formed.
Next, the nozzle plate 1 was dry etched to form a nozzle hole 4 having a diameter of 25 μm.

Next, the various components are bonded together as shown in Fig. 4. The common liquid chamber plate 83 is made of Si, and a common liquid chamber 84 and a partition wall 85 are formed in the shapes shown in Fig. 1 and Fig. 4. A metal member is used for the ceiling plate 86, and a supply path 87 is formed. Next, the various components are bonded together to produce the liquid ejection head of Example 1 shown in Fig. 1. Furthermore, electrodes having a thickness of 0.1 µm are formed on the top and bottom of the piezoelectric body 82.
When the amount of displacement of the nozzle plate 1 in the vicinity of the nozzle holes 4 of the obtained liquid ejection head was examined, the amount of nozzle displacement was 600 nm.

Next, as Comparative Example 1, a liquid ejection head shown in Figures 5 and 6 was fabricated in the same manner as in Example 1, except that the film formation temperature in Example 1 was changed to 800°C.

Next, the ejection characteristics of the obtained liquid ejection head were evaluated by ejecting ink onto a medium. The measurement conditions were as follows:

[Measurement conditions]
Number of nozzles: 1024 nozzles Standard droplet volume: 5 pl
Drop speed: 7m/sec
Distance between head and media: 1 mm
Ink type: Water-based pigment ink Ink viscosity: 5cp

The results are shown in Table 1. It can be seen that in this example, the variation in the ejection characteristics can be suppressed.
In the table, the droplet volume (max-min) indicates the difference between the droplet volume [pl] at which the volume of one droplet is maximum among the multiple nozzle holes in the liquid ejection head, and the droplet volume [pl] at which the volume of one droplet is minimum. In the table, the droplet speed (max-min) indicates the difference between the droplet speed [m/sec] at which the ejection speed is maximum among the multiple nozzle holes in the liquid ejection head, and the droplet speed [m/sec] at which the ejection speed is minimum. In addition, the amount of bending 3σ indicates the average value within the liquid ejection head. For these, the smaller the value, the less the variation.

Below, an embodiment of the liquid ejection head and liquid ejection device obtained by the present invention will be described. Figure 7 is a cross-sectional explanatory diagram along a direction perpendicular to the nozzle arrangement direction (longitudinal direction of the pressure chambers) of the liquid ejection head according to the embodiment, and Figure 8 is a cross-sectional explanatory diagram along the nozzle arrangement direction.

The liquid ejection head 100 of this embodiment is formed by laminating and bonding a nozzle plate 1 having a piezoelectric body, a flow path plate 2 which is an individual flow path member, and a vibration plate member 3 which serves as a wall member. It also has a common flow path member 20 which also serves as a frame member for the head. It may also further have a piezoelectric actuator 11 which displaces the vibration region (vibration plate) 30 of the vibration plate member 3.

The nozzle plate 1 has multiple nozzles 4 that eject liquid.

The flow path plate 2 forms a number of pressure chambers 6 that communicate with a number of nozzles 4, individual supply flow paths 7 that are individual flow paths that communicate with each pressure chamber 6, and an intermediate supply flow path 8 that serves as a liquid introduction section that communicates with one or more (one in this embodiment) individual supply flow paths 7.

The vibration plate member 3 has a plurality of displaceable vibration plates (vibration regions) 30 that form the walls of the pressure chamber 6 of the flow path plate 2. Here, the vibration plate member 3 has a two-layer structure (not limited to this) and is composed of a first layer 3A that forms a thin portion from the flow path plate 2 side, and a second layer 3B that forms a thick portion.

The thin first layer 3A forms a deformable vibration region 30 in the area corresponding to the pressure chamber 6. Within the vibration region 30, the thick convex portion 30a is formed in the second layer 3B, which is bonded to the piezoelectric actuator 11.

A piezoelectric actuator 11 including an electromechanical conversion element is disposed on the opposite side of the vibration plate member 3 from the pressure chamber 6 as a driving means (actuator means, pressure generating means) that deforms the vibration region 30 of the vibration plate member 3.

This piezoelectric actuator 11 is formed by forming grooves in a piezoelectric member bonded to a base member 13 by half-cut dicing, and forming a required number of columnar piezoelectric elements 12 in a comb shape at specified intervals in the nozzle arrangement direction. The piezoelectric elements 12 are then bonded to the protruding portions 30a, which are thick portions formed in the vibration region 30 of the vibration plate member 3.

This piezoelectric element 12 is made by alternately stacking piezoelectric layers and internal electrodes, with the internal electrodes each extending to the end faces and connected to external electrodes (end face electrodes), and flexible wiring members 15 are connected to the external electrodes.

The common flow path member 20 forms a common supply flow path 10 that connects to multiple pressure chambers 6. The common supply flow path 10 communicates with an intermediate supply flow path 8, which serves as a liquid introduction section, via an opening 9 provided in the vibration plate member 3, and communicates with the individual supply flow paths 7 via the intermediate supply flow path 8.

In this liquid ejection head 100, for example, by lowering the voltage applied to the piezoelectric element 12 from the reference potential (intermediate potential), the piezoelectric element 12 contracts, the vibration region 30 of the vibration plate member 3 is pulled, and the volume of the pressure chamber 6 expands, causing liquid to flow into the pressure chamber 6.

Then, the voltage applied to the piezoelectric element 12 is increased to expand the piezoelectric element 12 in the stacking direction, and the vibration region 30 of the vibration plate member 3 is deformed in the direction toward the nozzle 4, contracting the volume of the pressure chamber 6, thereby pressurizing the liquid in the pressure chamber 6 and ejecting the liquid from the nozzle 4.

Figure 9 is a cross-sectional explanatory diagram along a direction perpendicular to the nozzle arrangement direction (longitudinal direction of the pressure chambers) of a liquid ejection head in yet another embodiment. Figure 10 is a schematic perspective view of the liquid ejection head of this embodiment.

The liquid ejection head 100 of this embodiment is a circulation type liquid ejection head, and is made by laminating and bonding a nozzle plate 1, a flow path plate 2, and a vibration plate member 3 as a wall member. It also includes a piezoelectric actuator 11 that displaces the vibration region (vibration plate) 30 of the vibration plate member 3, and a common flow path member 20 that also serves as a frame member for the head.

The flow path plate 2 forms a plurality of pressure chambers 6 each connected to a plurality of nozzles 4 via a nozzle communication passage 5, a plurality of individual supply flow paths 7 each connected to a plurality of pressure chambers 6 and also serving as a fluid resistance portion, and one or more intermediate supply flow paths 8 serving as a liquid introduction portion connected to two or more individual supply flow paths 7.

As in the previous embodiment, the individual supply flow path 7 includes two flow paths, a first flow path section 7A and a second flow path section 7B, which have a higher fluid resistance than the pressure chamber 6, and a third flow path section 7C, which is disposed between the first flow path section 7A and the second flow path section 7B and has a lower fluid resistance than the first flow path section 7A and the second flow path section 7B.

The flow path plate 2 is constructed by stacking multiple plate-like members 2A to 2E, but is not limited to this.

The flow path plate 2 also forms a plurality of individual recovery flow paths 57 along the surface direction of the flow path plate 2, each of which is connected to a plurality of pressure chambers 6 via a nozzle communication passage 5, and one or more intermediate recovery flow paths 58 that serve as liquid outlet sections that are connected to two or more individual recovery flow paths 57.

The individual recovery flow path 57 includes two flow paths, a first flow path section 57A and a second flow path section 57B, which have a higher fluid resistance than the pressure chamber 6, and a third flow path section 57C, which is disposed between the first flow path section 57A and the second flow path section 57B and has a lower fluid resistance than the first flow path section 57A and the second flow path section 57B. The individual recovery flow path 57 includes a flow path section 57D, which is downstream of the second flow path section 57B in the circulation direction, and has the same flow path width as the third flow path section 57C.

The common flow path member 20 forms a common supply flow path 10 and a common recovery flow path 50. In this embodiment, the common supply flow path 10 is composed of a flow path portion 10A that is aligned with the common recovery flow path 50 in the nozzle arrangement direction, and a flow path portion 10B that is not aligned with the common recovery flow path 50.

The common supply flow path 10 communicates with an intermediate supply flow path 8, which serves as a liquid introduction section, through an opening 9 provided in the vibration plate member 3, and communicates with individual supply flow paths 7 through the intermediate supply flow path 8. The common recovery flow path 50 communicates with an intermediate recovery flow path 58, which serves as a liquid discharge section, through an opening 59 provided in the vibration plate member 3, and communicates with individual recovery flow paths 57 through the intermediate recovery flow path 58.

In addition, the common supply flow path 10 is connected to the supply port 71, and the common recovery flow path 50 is connected to the recovery port 72.

The other layer configurations of the diaphragm member 3 and the configuration of the piezoelectric actuator 11 are the same as those in the previous embodiment.

In this liquid ejection head 100, similarly to the above embodiment, the piezoelectric element 12 is expanded in the stacking direction, and the vibration area 30 of the vibration plate member 3 is deformed in the direction toward the nozzle 4 to contract the volume of the pressure chamber 6, thereby pressurizing the liquid in the pressure chamber 6 and ejecting the liquid from the nozzle 4.

In addition, liquid that is not ejected from the nozzle 4 passes through the nozzle 4 and is recovered from the individual recovery flow path 57 to the common recovery flow path 50, and is then resupplied from the common recovery flow path 50 to the common supply flow path 10 via an external circulation path. Even when liquid is not being ejected from the nozzle 4, liquid circulates from the common supply flow path 10 to the common recovery flow path 50 via the pressure chamber 6, and is then resupplied to the common supply flow path 10 via an external circulation path.

In this embodiment, too, a simple configuration can attenuate pressure fluctuations associated with liquid ejection and suppress propagation to the common supply flow path 10 and the common recovery flow path 50.

Next, an example of a liquid ejection device obtained by the present invention will be described with reference to Figures 11 and 12. Figure 11 is a schematic diagram of the device, and Figure 12 is a plan view of an example of a head unit of the device.

The printing device 500, which is a liquid ejection device, includes an input means 501 for inputting a continuous web 510, a guide and conveyance means 503 for guiding and conveying the continuous web 510, such as continuous paper or sheet material, input from the input means 501 to a printing means 505, a printing means 505 for ejecting liquid onto the continuous web 510 to print and form an image, a drying means 507 for drying the continuous web 510, and an ejection means 509 for ejecting the continuous web 510.

The continuous body 510 is sent out from the original winding roller 511 of the carrying-in means 501, guided and transported by the rollers of the carrying-in means 501, the guide and transport means 503, the drying means 507, and the carrying-out means 509, and then wound up by the winding roller 591 of the carrying-out means 509.

This continuous body 510 is transported on the transport guide member 559 in the printing means 505, facing the head unit 550 and the head unit 555, an image is formed by the liquid ejected from the head unit 550, and post-processing is performed with the processing liquid ejected from the head unit 555.

Here, the head unit 550 is arranged with, for example, full-line head arrays 551A, 551B, 551C, and 551D (hereinafter, when no distinction is made between colors, they will be referred to as "head array 551") for four colors from the upstream side in the transport direction.

Each head array 551 is a liquid ejection means, and ejects black K, cyan C, magenta M, and yellow Y liquid onto the transported continuum 510. Note that the types and number of colors are not limited to these.

The head array 551 is, for example, a liquid ejection head (also simply called a "head") 100 according to the present invention arranged in a staggered pattern on a base member 552, but is not limited to this.

The liquid ejection head and liquid ejection device obtained by the present invention may be configured to circulate liquid, for example, as a liquid circulation device using a liquid ejection head. An example of a liquid circulation device will be described with reference to FIG. 13. FIG. 13 is a block diagram of the circulation device. Note that only one head is shown here, but when multiple heads are arranged, a supply side liquid path and a recovery side liquid path will be connected to the supply side and recovery side of the multiple heads, respectively, via a manifold or the like.

The liquid circulation device 600 is composed of a supply tank 601, a recovery tank 602, a main tank 603, a first liquid delivery pump 604, a second liquid delivery pump 605, a compressor 611, a regulator 612, a vacuum pump 621, a regulator 622, a supply side pressure sensor 631, and a recovery side pressure sensor 632.

Here, the compressor 611 and the vacuum pump 621 constitute a means for generating a pressure difference between the pressure in the supply tank 601 and the pressure in the recovery tank 602.

The supply side pressure sensor 631 is located between the supply tank 601 and the head 100, and is connected to a supply side liquid path connected to the supply port 71 of the head 100. The recovery side pressure sensor 632 is located between the head 1 and the recovery tank 602, and is connected to a recovery side liquid path connected to the recovery port 72 of the head 100.

One side of the recovery tank 602 is connected to the supply tank 601 via a first liquid delivery pump 604, and the other side of the recovery tank 602 is connected to the main tank 603 via a second liquid delivery pump 605.

As a result, liquid flows from the supply tank 601 through the supply port 71 into the head 100, is collected from the collection port 72 into the collection tank 602, and the first liquid supply pump 604 sends the liquid from the collection tank 602 to the supply tank 601, thereby forming a circulation path through which the liquid circulates.

Here, a compressor 611 is connected to the supply tank 601, and is controlled so that a specified positive pressure is detected by a supply side pressure sensor 631. On the other hand, a vacuum pump 621 is connected to the recovery tank 602, and is controlled so that a specified negative pressure is detected by a recovery side pressure sensor 632.

This allows liquid to circulate through the head 100 while maintaining a constant negative pressure at the meniscus.

In addition, when liquid is ejected from the nozzle 4 of the head 100, the amount of liquid in the supply tank 601 and the recovery tank 602 decreases. Therefore, the second liquid supply pump 605 is used to replenish liquid from the main tank 603 to the recovery tank 602 as appropriate.

The timing of refilling the liquid from the main tank 603 to the recovery tank 602 can be controlled based on the detection results of a liquid level sensor installed in the recovery tank 602, such as refilling the liquid when the liquid level in the recovery tank 602 falls below a predetermined level.

Next, another example of a printing device as a liquid ejection device obtained by the present invention will be described with reference to Figures 14 and 15. Figure 14 is a plan view of the main parts of the device, and Figure 15 is a side view of the main parts of the device.

This printing device 500 is a serial type device, and the carriage 403 is moved back and forth 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 hung between left and right side plates 491A, 491B and holds the carriage 403 movably. The carriage 403 is then moved back and forth in the main scanning direction by the main scanning motor 405 via the timing belt 408 hung between the drive pulley 406 and driven pulley 407.

This carriage 403 is equipped with a liquid ejection unit 440 that integrates a liquid ejection head 100 and a head tank 441. The liquid ejection head 100 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 100 is mounted with a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward.

The liquid ejection head 100 is connected to the liquid circulation device 600 described above, and liquid of the required color is circulated and supplied.

This printing device 500 is equipped with a transport mechanism 495 for transporting paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

The conveyor belt 412 attracts the paper 410 and conveys it to a position facing the liquid ejection head 100. The conveyor belt 412 is an endless belt that is stretched between a conveyor roller 413 and a tension roller 414. The paper can be attracted by electrostatic attraction or air suction.

The conveyor belt 412 moves in a circular motion in the sub-scanning direction as the conveyor roller 413 is rotated and driven by the sub-scanning motor 416 via the timing belt 417 and timing pulley 418.

Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head 100 is arranged on one side of the carriage 403 in the main scanning direction, beside the conveyor belt 412.

The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzles are formed) of the liquid ejection head 100, and a wiper member 422 that wipes the nozzle surface.

The main scanning movement mechanism 493, the maintenance recovery mechanism 420, and the transport mechanism 495 are attached to a housing that includes side plates 491A, 491B, and a back plate 491C.

In the printing device 500 configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereto, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412.

Then, by moving the carriage 403 in the main scanning direction and driving the liquid ejection head 100 in response to an image signal, liquid is ejected onto the stationary paper 410 to form an image.

Next, an example of a liquid ejection unit using a liquid ejection head obtained by the present invention will be described with reference to FIG. 16. FIG. 16 is a plan view of the main parts of the unit.

Of the components constituting the liquid ejection device, this liquid ejection unit 440 is composed of a housing portion formed of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 100.

It is also possible to configure a liquid ejection unit by further attaching the aforementioned maintenance and recovery mechanism 420 to, for example, the side plate 491B of this liquid ejection unit 440.

Next, another example of a liquid ejection unit will be described with reference to FIG. 17. FIG. 17 is a front view of the unit.

This liquid ejection unit 440 is composed of a liquid ejection head 100 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444.

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 is provided on the upper part of the flow path part 444 to electrically connect to the liquid ejection head 100.

In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited, but it is preferable that the viscosity is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, etc. that contains a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural dye, etc., and these can be used for applications such as inkjet ink, surface treatment liquid, a liquid for forming a component of an electronic element or a light-emitting element, an electronic circuit resist pattern, a material liquid for three-dimensional modeling, etc.

The energy sources for discharging liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators that consist of a vibration plate and an opposing electrode.

A "liquid ejection unit" is a liquid ejection head that is integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a liquid ejection head that is combined with at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.

Here, integration includes, for example, the liquid ejection head, functional parts, and mechanism being fixed to each other by fastening, bonding, engagement, etc., and one being held movably relative to the other. The liquid ejection head, functional parts, and mechanism may also be configured to be detachable from each other.

For example, some liquid ejection units have a liquid ejection head and a head tank integrated together. Others have a liquid ejection head and a head tank integrated together by connecting them to each other with 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.

There are also liquid ejection units in which the liquid ejection head and carriage are integrated.

In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated. In other liquid ejection units, the liquid ejection head, carriage, and main scanning movement mechanism are integrated.

In some liquid ejection units, 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, integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

In addition, some liquid ejection units have a head tank or a liquid ejection head to which a flow path component is attached, and a tube is connected to the liquid ejection head, integrating the liquid ejection head with a supply mechanism. Liquid from a liquid storage source is supplied to the liquid ejection head via this tube.

The main scanning movement mechanism includes the guide member alone. The supply mechanism also includes the tube alone and the loading section alone.

"Devices that eject liquid" include devices that have a liquid ejection head or liquid ejection unit and eject liquid by driving the liquid ejection head. Devices that eject liquid include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

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.

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 to form a three-dimensional object.

In addition, a "liquid ejecting 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.

The above phrase "something to which liquid can adhere" refers to something to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or adheres and penetrates. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all things to which liquid can adhere.

The above-mentioned "materials to which liquid can adhere" include paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, and other materials to which liquid can adhere even temporarily.

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

Other examples of "liquid ejecting devices" include treatment liquid application devices that eject treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and spray granulation devices that spray a composition liquid in which raw materials are dispersed through a nozzle to granulate the raw material into fine particles.

In this application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

REFERENCE SIGNS LIST 1 nozzle plate 1b, 1c nozzle surface 4 nozzle hole 81 substrate 82 piezoelectric body 83 common liquid chamber plate 84 common liquid chamber 85 partition wall 86 ceiling plate 87 supply path 88 ink

Japanese Patent Application Publication No. 3-65350 Patent No. 3427608

Claims (6)

A method for manufacturing a liquid ejection head that ejects liquid by vibrating a nozzle plate having a substrate and a piezoelectric body, comprising:
a piezoelectric body forming step of forming the piezoelectric body on the substrate at 450° C. to 600° C.;
a nozzle hole forming step of forming a nozzle hole penetrating the substrate and the piezoelectric body ,
The method for manufacturing a liquid ejection head , wherein the piezoelectric body forming step forms the piezoelectric body by a sputtering method or a CVD (Chemical Vapor Deposition) method . The method for manufacturing a liquid ejection head according to claim 1, characterized in that the piezoelectric body is PZT (lead zirconate titanate). The method for manufacturing a liquid ejection head according to claim 1 or 2, characterized in that the piezoelectric body forming process forms the piezoelectric body at 450°C to 550°C. 4. The method for manufacturing a liquid ejection head according to claim 1 , wherein the nozzle hole forming step forms the nozzle hole by dry etching. 5. The method for manufacturing a liquid ejection head according to claim 1 , further comprising, after the nozzle hole forming step, a bonding step of bonding a common liquid chamber substrate to the substrate side of the nozzle plate. A method for manufacturing a liquid ejection device, comprising the steps of: manufacturing a liquid ejection device by using the method for manufacturing a liquid ejection head according to any one of claims 1 to 5 .

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