JP7743771B2 - Liquid ejection head, liquid ejection unit, and liquid ejection device - Google Patents

Description

The present invention relates to a liquid ejection head, a liquid ejection unit, and a device for ejecting liquid.

In a liquid ejection head that ejects liquid, a technology is known in which a film-like member having nozzle holes is vibrated to eject droplets.

Patent Document 1 discloses that a membrane-like member with a nozzle formed thereon is vibrated to eject a cell solution in the form of droplets. According to Patent Document 1, the cell solution can be ejected stably.

Patent Document 2 discloses a droplet formation device having a film-like member with ejection holes formed therein and two or more vibration means for vibrating the film-like member, with one or more vibration means disposed in each region of the film-like member where the polarity of the bending moment differs. According to Patent Document 2, the device provides sufficient driving force by increasing the displacement efficiency of the film-like member, and also improves droplet productivity by shortening the residual vibration of the film-like member.

Patent Document 3 discloses a liquid ejection device having a nozzle plate made of a piezoelectric material in which nozzles are formed, a flow path structure in which liquid flow paths are formed, and first and second electrodes respectively arranged in the peripheral areas of the nozzles on both sides of the nozzle plate. Patent Document 3 discloses that when ejection energy is applied to the liquid in the liquid flow path by an energy application means, it is determined whether the ejection state of droplets from the nozzles is normal or not based on the potential difference between the first and second electrodes, and according to Patent Document 3, it is possible to detect whether the ejection state of droplets is normal or not.

Patent Document 3 also discloses providing slits extending radially from the nozzle in the areas of the nozzle plate between the multiple divided first electrodes. This separates each of the nozzle plate's sections where the first electrodes (61) are located from adjacent sections by the slits, making it easier for the sections where the first electrodes are located to deform independently.

However, conventional technology has not been able to sufficiently prevent uneven vibration displacement around the nozzle holes, and there is a need to solve the problem of droplets not being ejected straight from the nozzle holes. Furthermore, when uneven vibration displacement around the nozzle holes occurs, ejection varies from nozzle to nozzle, resulting in problems such as droplet speed varying from nozzle to nozzle, making it difficult to achieve good ejection characteristics.

One possible solution to this problem, as in Patent Document 3, is to divide the electrodes around the nozzle holes and apply different potentials to each electrode to correct the error and adjust the ink so that it is ejected in a straight line. However, this not only complicates the configuration of the drive circuit, but also requires obtaining a correction value for each nozzle hole, making the correction process much more time-consuming. Furthermore, dividing the electrodes as in Patent Document 3 increases manufacturing costs.

The present invention aims to provide a liquid ejection head that can uniformly displace vibrations around the nozzle holes, achieve good ejection characteristics, and keep costs down.

In order to solve the above problem, the liquid ejection head of the present invention has a nozzle plate consisting of multiple layers including a base layer, a piezoelectric layer, a first electrode and a second electrode, a nozzle hole penetrating the nozzle plate, and a liquid chamber communicating with the nozzle hole, wherein the first electrode is provided between the base layer and the piezoelectric layer, and the second electrode is provided on the opposite side of the first electrode via the piezoelectric layer, the nozzle plate has a slit connected to the nozzle hole in the area surrounding the nozzle hole, the first electrode is continuous near the end of the slit in the longitudinal direction when viewed in a plane, and the second electrode is continuous near the end of the slit in the longitudinal direction when viewed in a plane .

This invention makes it possible to provide a liquid ejection head that can uniformly displace vibrations around the nozzle holes, achieves good ejection characteristics, and is cost-effective.

1 is a perspective view showing an external appearance of an example of a liquid ejection head according to the present invention. FIG. 2 is a schematic plan view illustrating an example of a nozzle plate. 1 is a schematic cross-sectional view showing an example of a liquid ejection head according to the present invention. FIG. 10 is a schematic cross-sectional view showing another example of a liquid ejection head according to the present invention. 1A is a schematic cross-sectional view illustrating a state in which a nozzle plate in an example of a liquid ejection head according to the present invention is not deformed, and FIG. 1B is a schematic plan view illustrating the state in which a nozzle plate in an example of a liquid ejection head according to the present invention is not deformed. 1A is a schematic cross-sectional view illustrating a state in which a nozzle plate in an example of a liquid ejection head according to the present invention is deformed, and FIG. 1B is a schematic plan view illustrating the state in which a nozzle plate in an example of a liquid ejection head according to the present invention is deformed. FIG. 10 is a schematic cross-sectional view showing another example of a liquid ejection head according to the present invention. FIG. 10 is a schematic cross-sectional view showing another example of a liquid ejection head according to the present invention. FIG. 10 is a schematic cross-sectional view showing another example of a liquid ejection head according to the present invention. 1A and 1B are schematic plan views showing another example of a liquid ejection head according to the present invention. FIG. 10 is a schematic plan view showing another example of a liquid ejection head according to the present invention. 1 is a schematic diagram illustrating an example of a liquid ejection device according to the present invention. FIG. 2 is a schematic diagram illustrating an example of an ink tank. 1 is a schematic diagram illustrating an example of a liquid ejection device according to the present invention. FIG. 10 is a schematic view showing another example of the device for discharging liquid according to the present invention. FIG. 2 is a schematic diagram illustrating an example of a liquid ejection unit. FIG. 10 is a schematic diagram illustrating another example of the liquid ejection unit. 1A is a schematic cross-sectional view of a liquid ejection head according to a conventional example, and FIG. 1B is a schematic plan view thereof. 10A is a schematic plan view of a liquid ejection head according to another conventional example, and FIG. 10B is a schematic cross-sectional view thereof.

The liquid ejection head, liquid ejection unit, and liquid ejection device according to the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments shown below, and can be modified, including other embodiments, additions, modifications, and deletions, within the scope of what one skilled in the art can conceive. Any embodiment that achieves the effects and advantages of the present invention is within the scope of the present invention.

(Liquid ejection head)
The liquid ejection head of this embodiment has a nozzle plate consisting of multiple layers including a base layer, a piezoelectric layer, a first electrode, and a second electrode, a nozzle hole penetrating the nozzle plate, and a liquid chamber communicating with the nozzle hole, wherein the first electrode is provided between the base layer and the piezoelectric layer, the second electrode is provided on the opposite side of the first electrode via the piezoelectric layer, the nozzle plate has a slit connected to the nozzle hole in the area surrounding the nozzle hole, and the first electrode and the second electrode are not separated by the slit.

The liquid ejection head according to this embodiment includes a nozzle plate made up of multiple layers including a base layer, a piezoelectric layer, a first electrode, and a second electrode, a nozzle hole penetrating the nozzle plate, and a liquid chamber communicating with the nozzle hole, wherein the first electrode is provided between the base layer and the piezoelectric layer, and the second electrode is provided on the opposite side of the first electrode across the piezoelectric layer, and the nozzle plate has a slit connected to the nozzle hole in the region surrounding the nozzle hole, and the first electrode is continuous near the end of the slit in the longitudinal direction in a planar view, and the second electrode is continuous near the end of the slit in the longitudinal direction in a planar view.

In another embodiment, a liquid ejection head has a nozzle plate made up of multiple layers including a base layer, a piezoelectric layer, a first electrode, and a second electrode, a nozzle hole penetrating the nozzle plate, and a liquid chamber communicating with the nozzle hole, wherein the first electrode is provided between the base layer and the piezoelectric layer, and the second electrode is provided on the opposite side of the first electrode across the piezoelectric layer, and the nozzle plate has a slit connected to the nozzle hole in at least one of the multiple layers in the area surrounding the nozzle hole, and the first electrode and the second electrode are not separated by the slit.

First, a perspective view of the appearance of the liquid ejection head of this embodiment is shown in FIG.
In the illustrated liquid ejection head, the bottom surface is a nozzle plate 1, and liquid is ejected from nozzle holes 1a provided in the nozzle plate 1.
The nozzle holes 1a communicate with the flow path member 20, the common liquid chamber member 40, and the supply ports 71 in this order, and liquid is supplied from the supply ports 71. The arrangement and number of the supply ports 71 are not limited to those shown in the drawing.

The flow path member 20 forms a liquid chamber (which may also be called a pressure chamber, an individual liquid chamber, etc.) and may also be called a partition member, etc., since it forms a partition wall between the liquid chambers.
The common liquid chamber member 40 forms a common liquid chamber, which communicates with each liquid chamber.
As shown in the figure, the liquid ejection head of this embodiment may have a cover 72 .
If necessary, a circulation port may be provided to circulate the liquid.

Figure 2 is a schematic plan view showing an example of a nozzle plate, and is an example of a plan view of the nozzle plate when viewed from below the liquid ejection head. Nozzle plate 1 is attached to the bottom surface of the liquid ejection head, and nozzle holes 1a for ejecting liquid are provided in nozzle plate 1.

The nozzle plate 1 may have a nozzle row in which multiple nozzle holes 1a are arranged. The nozzle row may be, for example, a single row as shown in FIG. 2(a), or multiple rows as shown in FIG. 2(b). Furthermore, when multiple nozzle rows are provided, the nozzle rows may be offset so that the nozzle holes 1a are arranged in a staggered pattern.

In the figure, arrow 10 indicates the short-side direction of nozzle plate 1, and arrow 11 indicates the long-side direction of nozzle plate 1. As in the example shown in the figure, it is preferable that nozzle holes 1a are arranged along the long-side direction, but this is not limited to this and they may also be arranged at an angle.

Next, the liquid ejection head of this embodiment will be further described using a schematic cross-sectional view.
FIG. 3 is a schematic cross-sectional view of the liquid ejection head taken along a plane parallel to the nozzle rows.

The nozzle plate 1 includes a base layer 12, a piezoelectric layer 13, a first electrode, and a second electrode, and may also have a protective layer 14 as necessary. As will be described later, it may also have a water-repellent film as necessary. In the illustrated example, the base layer 12, piezoelectric layer 13, and protective layer 14 are formed in this order from the liquid chamber 21 side. The liquid ejection surface of the nozzle plate 1 is indicated by the reference symbol 1b.
In FIG. 3, the electrodes are not shown.

The material of the substrate layer 12 can be selected appropriately, and for example, Si can be used.
For example, PZT (lead zirconate titanate) can be used as the piezoelectric layer 13. Alternatively, the piezoelectric layer 13 can be obtained by forming columnar crystals on the base layer 12 in the direction in which the nozzle holes 1a penetrate.
The protective layer 14 can be made of any suitable material, for example, a resin.

The nozzle holes 1a are formed to penetrate the nozzle plate 1. In this embodiment, the direction from one hole to the other in the nozzle holes 1a is also referred to as the liquid ejection direction.

The flow path member 20 has a liquid chamber 21 that communicates with the nozzle hole 1a. The liquid chamber 21 may have openings other than the nozzle hole 1a, and may be connected to a liquid supply path or liquid circulation path. In the example shown, the flow path member 20 has a supply path 26, and liquid is supplied to the liquid chamber 21 through the supply path 26.

The flow path member 20 has partition walls 24 that separate the liquid chambers 21, and is also referred to as a partition wall member. The flow path member 20 is bonded to the nozzle plate 1, and the bonded area is indicated by the reference symbol 28.

In the liquid ejection head of this embodiment, a voltage is applied to the piezoelectric layer 13, causing it to deform, thereby applying pressure to the liquid in the liquid chamber 21 and ejecting the liquid (e.g., ink) from the nozzle hole 1a.

In the example shown in Figure 3, each nozzle is assigned one liquid chamber separated by a partition wall 24, but the liquid chambers of each nozzle do not necessarily have to be separated. For example, part of the partition wall may be used as a support.

Figure 4 shows another example of this embodiment. Figure 4 is a schematic cross-sectional view of a liquid ejection head, showing a cross section perpendicular to the nozzle arrangement direction. In the example shown here, part of the partition wall 24 has been modified. Electrodes are not shown in Figure 4.

As shown in the figure, the support pillars 25 that separate the liquid chambers 21 do not have their tops in contact with the ceilings of the liquid chambers 21 (the upper part of the page). By using the support pillars 25 as part of the partition wall, the partition wall that separates the liquid chambers 21 as shown in the figure, liquid can move between the liquid chambers 21. In other words, liquid can move from one liquid chamber 21 to another liquid chamber 21.

In the example shown in FIG. 4, a water-repellent film 15 is provided on the protective layer 14. By providing the water-repellent film 15, it is possible to further prevent the nozzle plate 1 from becoming soiled with liquid. Note that the example shown in FIG. 3 may also have a water-repellent film 15. The water-repellent film may also be referred to as a liquid-repellent film.

Next, a detailed example of this embodiment will be described using Figures 5A and 5B. Figure 5A(a) is a schematic cross-sectional view of the main parts of a liquid ejection head, and Figure 5A(b) is a schematic plan view of the main parts as viewed from the liquid ejection surface of Figure 5A(a). Similarly, Figure 5B(a) is a schematic cross-sectional view of the main parts of a liquid ejection head, and Figure 5B(b) is a schematic plan view of the main parts as viewed from the liquid ejection surface of Figure 5B(a).

In this embodiment, the nozzle plate 1 is made up of multiple layers including a base layer 12, a piezoelectric layer 13, a first electrode 16, and a second electrode 17, and may have a protective layer 14 or the like as needed. The nozzle plate 1 also has a slit 31 connected to the nozzle hole 1a in the area surrounding the nozzle hole 1a. The presence of the slit 31 makes it possible to make the vibration displacement around the nozzle hole 1a uniform, thereby improving the ejection characteristics.

Figure 5A is a schematic cross-sectional view (a) and a schematic plan view (b) showing the nozzle plate 1 in an undeformed state. Figure 5A(b) is a schematic plan view of the liquid ejection head of this embodiment as viewed from below. In other words, it is a schematic plan view of Figure 5A(a) as viewed from the liquid ejection surface 1b, or more specifically, as viewed from a direction perpendicular to the surface of the nozzle plate 1, illustrating the essential parts. The cross section AA of Figure 5A(b) corresponds to Figure 5A(a).

Figure 5B is a schematic cross-sectional view and a schematic plan view showing the state when the nozzle plate 1 is deformed. Figure 5B(b) is a schematic plan view similar to Figure 5A(b). The AA cross section of Figure 5B(b) corresponds to Figure 5B(a). As shown in Figure 5B(a), the area around the nozzle hole 1a is displaced and vibrates, causing liquid (e.g., ink) to be ejected.

In Figure 5B (b), the white arrows schematically show the tension that occurs when the area around the nozzle hole 1a is displaced. In this embodiment, a slit 31 connected to the nozzle hole 1a is provided in the area around the nozzle hole 1a, thereby significantly reducing the tension that occurs when the area around the nozzle hole 1a is displaced. This makes it possible to uniformize the vibration displacement around the nozzle hole 1a, allowing droplets to be ejected straight. Furthermore, because the vibration displacement around the nozzle hole 1a can be uniform, it is possible to suppress variations in vibration displacement between nozzle holes and variations in droplet speed between nozzle holes. This allows for stable ejection and improves ejection characteristics compared to conventional methods.

Figure 17 shows a schematic cross-sectional view of a conventional liquid ejection head. Similar to Figure 5B, Figure 17 shows a schematic cross-sectional view (a) and a schematic plan view (b) that show the state when nozzle plate 1' is deformed.

In the conventional example, there is no slit in the area surrounding the nozzle hole 1a. As a result, the vibration displacement around the nozzle hole 1a cannot be made uniform, and good ejection characteristics cannot be obtained.

As shown schematically in Figure 5B (b), in a liquid ejection head that ejects liquid by vibrating the components surrounding a small nozzle hole formed on a flat surface, tension is generated in the surrounding components when the components surrounding the nozzle hole 1a are displaced.

In conventional examples, as shown in Figure 17(b), for example, the tension generated in the material surrounding the nozzle hole 1a is not uniform, and slight differences in the thickness or shape of the surrounding material cause tension differences depending on the location. As a result, as shown in Figure 17(a), the vibration displacement around the nozzle hole 1a is not uniform, and the nozzle hole 1a also becomes tilted. This causes problems such as droplets not being ejected in a straight line and droplet speeds varying from nozzle to nozzle.

One possible solution to this problem would be to divide the electrodes around the nozzle holes and apply different potentials to each electrode to correct the error and adjust the ink so that it is ejected in a straight line. However, this would not only complicate the configuration of the drive circuit, but would also require obtaining a correction value for each nozzle hole, making the correction process much more time-consuming.

In contrast, as described above, in this embodiment, slits 31 connected to the nozzle holes 1a are provided in the area surrounding the nozzle holes 1a, which makes it possible to uniformize vibration displacement around the nozzle holes 1a and improve ejection characteristics. This also avoids problems such as the complicated configuration of the drive circuit in the liquid ejection head.

Next, a detailed example of the slit will be described.
Fig. 6 is a schematic cross-sectional view showing the cross section taken along line BB in Fig. 5A(b), in which the nozzle hole 1a is indicated by a broken line.
As shown in the figure, the slits 31 are formed in the base material layer 12, the piezoelectric layer 13, the first electrode 16, the second electrode 17, and the protective layer 14. In this way, when the nozzle plate 1 is made up of multiple layers, the slits 31 may be formed in all of the multiple layers. When slits are formed in all of the layers that make up the nozzle plate 1, it is possible to significantly reduce the tension that occurs when the members around the nozzle hole 1a are displaced.

In this embodiment, the first electrode 16 and the second electrode 17 are not divided by a slit 31. For example, as can be seen from the schematic plan view shown in FIG. 5A(b) and the schematic cross-sectional view of cross section B-B of FIG. 5A(b) shown in FIG. 6, the first electrode 16 and the second electrode 17 are not divided by a slit 31. Note that FIG. 5A(b) also shows the reference numerals 16a and 17a, which are also referred to as continuous regions.

More specifically, as shown in Figure 5A (b), the first electrode 16 is divided by slits 31, but the divided areas are connected by continuous areas 16a. Therefore, the first electrode 16 is not divided by slits 31. As a result, for example, only one wiring is required for the first electrode 16, and the divided areas become a common electrode.

Similarly, although the second electrode 17 is partitioned by the slits 31, the partitioned areas are connected by continuous areas 17a. Therefore, the second electrode 17 is not divided by the slits 31. As a result, for example, only one wiring is required for the second electrode 17, and the partitioned areas become a common electrode.

In the example shown in Figure 5A (b), four continuous regions are shown. Also, in Figure 6, continuous regions 16a and 17a are shown.

In this way, in this embodiment, the first electrode 16 and the second electrode 17 are not separated by a slit 31, which prevents the electrode fabrication from becoming complicated and also prevents the wiring from becoming complicated. This reduces manufacturing costs.

The fact that the first electrode 16 and the second electrode 17 are not divided by the slit 31 can also be expressed in other ways. For example, in this embodiment, the first electrode 16 is continuous near the end of the longitudinal direction of the slit 31 in a planar view, and the second electrode 17 is continuous near the end of the longitudinal direction of the slit 31 in a planar view. This can be said to be a different way of expressing what is shown in Figures 5A(b) and 5B(b). The areas near the end of the longitudinal direction of the slit 31 in a planar view correspond to the continuous regions 16a and 17a.

Here, another conventional example will be described using Figure 18. Figure 18(a) is a schematic plan view of this conventional example, and is a schematic plan view similar to Figure 5A(b). Figure 18(b) is a schematic cross-sectional view of this conventional example, and is a cross-section taken along CC in Figure 18(a).

As shown in the figure, the first electrode 16 is divided by a slit 31. On the other hand, the second electrode 17 is not divided by a slit 31, and Figure 18 (b) shows a continuous region 17a. When at least one of the first electrode 16 and the second electrode 17 is divided by a slit 31 in this way, the wiring becomes complicated, increasing manufacturing costs. In addition, wiring must be performed on each of the divided first electrodes 16, which increases costs and effort. Furthermore, if the driving of the divided first electrode 16 or second electrode 17 varies due to the wiring conditions, etc., it is impossible to uniform the vibration displacement around the nozzle hole, and good ejection characteristics cannot be obtained.

Next, other embodiments will be described, and explanations of matters similar to those described above will be omitted.
In this embodiment, when the nozzle plate 1 is made up of multiple layers, a slit may be provided in at least one of the multiple layers in the region around the nozzle hole 1 a. Even if slits are not formed in all of the layers that make up the nozzle plate 1, the vibration displacement around the nozzle hole 1 a can be made uniform, and the effects of the present invention can be obtained.

Furthermore, when slits 31 are provided in some of the multiple layers in the nozzle plate 1, i.e., when slits are not formed in all of the layers that make up the nozzle plate 1, ink evaporation from the slits can be prevented more effectively than when slits are formed in all of the layers that make up the nozzle plate 1. In more detail, when slits 31 are not formed in all of the layers, the slits 31 do not communicate from the liquid chamber 21 to the liquid ejection surface 1b, and drying of ink through the slits 31 can be prevented. This makes it possible to achieve stable ejection even in low-humidity environments or environments where ejection is not performed for long periods of time.

An example of such a slit is given below.
7 is a schematic cross-sectional view similar to FIG. 6, and can be said to correspond to the cross section BB in FIG. 5A(b). In the example shown, slits 31 are provided in the protective layer 14. In other words, when the liquid ejection surface side of the nozzle plate 1 is considered to be the outermost surface, the slits 31 are provided in the outermost layer.

Next, other examples of this embodiment will be described.
Fig. 8 is a schematic cross-sectional view similar to Fig. 7. In the example shown, slits 31 are provided in the base layer 12, the piezoelectric layer 13, the first electrode 16, and the second electrode 17, but no slits 31 are provided in the protective layer 14. In other words, when the liquid ejection surface side of the nozzle plate 1 is considered to be the outermost surface, the slits 31 are provided in a layer other than the outermost layer.

It is preferable that the slits 31 are provided in at least the layer with the highest Young's modulus among the multiple layers in the nozzle plate 1. In this case, the nozzle plate 1 becomes more easily displaced, further improving the ejection characteristics.

Furthermore, when the slits 31 are provided in some of the multiple layers of the nozzle plate 1, and the liquid ejection surface side of the nozzle plate 1 is considered to be the outermost surface, it is preferable that the slits 31 be provided in a layer other than the outermost layer. From this perspective, when comparing Figures 7 and 8, the example shown in Figure 8 is preferable. In the example shown in Figure 8, the protective layer 14 is considered to be the outermost layer, and the slits 31 are provided in the layer of the protective layer 14, which is the outermost layer.

In this case, the surface shape of the nozzle plate 1 is flat, without any unevenness or grooves, which prevents ink from clogging or solidifying in the unevenness or grooves on the surface (liquid ejection surface) of the nozzle plate 1. This makes it easier to maintain a stable ejection state over a long period of time, and makes it easier to maintain good ejection characteristics.

The shape of the slits 31 can be selected as appropriate, but it is preferable that they have a shape that extends radially from the center of the nozzle hole 1a. By having a shape that extends radially from the center of the nozzle hole 1a, the tension when the nozzle plate 1 deforms is reduced, allowing for more stable, straighter droplets to be ejected.

The shape of the radially extending portions can be selected appropriately, and may be a cross shape as shown in FIG. 5A(b) and FIG. 5B(b).
Further, other examples of the shape of the slits 31 are shown in Fig. 9. Fig. 9 is a schematic plan view similar to Fig. 5. Fig. 9(a) is an example in which the number of slits 31 is greater than in the example shown in Fig. 5, and Fig. 9(b) is an example in which the number of slits 31 is less than in the example shown in Fig. 5. The examples shown in Fig. 5 and Fig. 9(a) can be said to be examples of shapes extending radially.

The shape of the slits 31 is not particularly limited, but it is more preferable that they have a cross shape extending radially as shown in Figures 5A(b) and 5B(b). In this case, it is possible to reduce the number of locations where the slits 31 are formed, while also reducing the tension generated in the area around the nozzle hole 1a.

Furthermore, it is preferable that the shape of the slits 31 be arranged so that they are rotationally symmetrical about the center of the nozzle hole 1a. The examples shown in Figures 5 and 9 are examples of arrangements that are rotationally symmetrical. In this case, it is possible to prevent unevenness in the magnitude of deformation when the nozzle plate 1 deforms, and it is possible to eject droplets that are more stable and straight.

It is also preferable that part or all of the slits 31 are sealed with an elastic member. In this case, the effect of reducing tension by the slits 31 can be obtained while ink is prevented from entering the slits 31. This prevents problems that arise when ink that has entered the slits 31 dries, and prevents, for example, a decrease in the effect of reducing tension by the slits 31. Furthermore, when the slits 31 are formed in the outermost layer, sealing part or all of the slits 31 with an elastic member can prevent ink from clogging or solidifying.

The elastic material can be selected appropriately, and known materials can be used.

Figure 10 shows an example in which part or all of the slit 31 is sealed with an elastic member. Figure 10 is a schematic plan view similar to Figure 5. As shown, the slit 31 is sealed with an elastic member 32. In this example, the entire slit 31 is sealed with the elastic member 32.

In this embodiment, the method for forming the slits can be selected as appropriate. For example, the slits may be created after the multiple layers of the nozzle plate 1 are formed, or when the multiple layers of the nozzle plate 1 are formed, each layer may be formed so that it has a slit shape.

(Liquid ejection device, liquid ejection unit)
Next, the liquid ejecting device of the present invention will be described, taking a recording device as an example of the liquid ejecting device of the present invention.
The liquid ejection head of the present invention can be used in various recording devices using the ink jet recording method, such as printers, facsimile machines, copying machines, printer/fax/multifunction machines, three-dimensional modeling devices, and bioprinters.

In this invention, a recording device and a recording method refer to a device capable of ejecting ink, various treatment liquids, etc. onto a recording medium, and a method of recording using such a device. A recording medium refers to anything onto which ink or various treatment liquids can be attached, even temporarily.

This recording device can include not only the head portion that ejects ink, but also means for feeding, transporting, and discharging the recording medium, as well as other devices known as pre-processing devices and post-processing devices.

The recording apparatus and recording method may have a heating means used in the heating process and a drying means used in the drying process. Heating means and drying means include, for example, means for heating and drying the printed surface and back surface of the recording medium. The heating means and drying means are not particularly limited, but examples include hot air heaters and infrared heaters. Heating and drying can be performed before, during, or after printing.

In addition, recording devices and recording methods are not limited to those that visualize meaningful images such as letters and figures using ink. For example, they also include those that form patterns such as geometric shapes and those that create three-dimensional images. Furthermore, unless otherwise specified, recording devices include both serial-type devices that move a liquid ejection head and line-type devices that do not move an ejection head. Furthermore, this recording device includes not only desktop types, but also wide-format recording devices that can print on A0-sized recording media, and continuous-feed printers that can use, for example, continuous paper wound into a roll as a recording medium.

An example of a recording device will be described with reference to Figures 11 and 12. Figure 11 is a perspective view of the device. Figure 12 is a perspective view of the main tank. An image forming device 400, which is an example of a recording device, is a serial image forming device. A mechanism section 420 is provided within the exterior casing 401 of the image forming device 400.

Each ink storage section 411 of the main tanks 410 (410k, 410c, 410m, 410y) for each color - black (K), cyan (C), magenta (M), and yellow (Y) - is formed from a packaging material such as aluminum laminate film. The ink storage section 411 is housed in a storage container case 414 made of, for example, plastic. This allows the main tanks 410 to be used as ink cartridges for each color.

Meanwhile, a cartridge holder 404 is provided at the back of the opening that is visible when the cover 401c of the device body is opened. A main tank 410 is removably attached to the cartridge holder 404. This allows each ink outlet 413 of the main tank 410 to communicate with the ejection head 434 for each color via the supply tube 436 for each color, making it possible to eject ink from the ejection head 434 onto the recording medium.

Note that the recording medium used for recording is not particularly limited, but examples include plain paper, glossy paper, special paper, cloth, film, overhead projector sheets, general-purpose printing paper, etc.

Next, another example of a liquid ejection device according to the present invention will be described with reference to Figures 13 and 14. Figure 13 is a plan view of the main parts of the device, and Figure 14 is a side view of the main parts of the device.

This device is a serial type device, and the carriage 403 is moved back and forth 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, 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 a drive pulley 406 and a driven pulley 407.

This carriage 403 is equipped with a liquid ejection unit 440 that integrates a liquid ejection head 404 according to the present invention and a head tank 441. 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 consisting of multiple nozzles 11 arranged in the sub-scanning direction perpendicular to the main scanning direction, with the ejection direction facing downward.

The head tank 441 is supplied with liquid stored in the liquid cartridge 450 by a supply mechanism 494 that supplies liquid stored outside the liquid ejection head 404 to the liquid ejection head 404.

The supply mechanism 494 is composed 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 other components. 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 by the liquid delivery unit 452 via the tube 456.

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

The conveyor belt 412 attracts the paper 410 and transports it at a position facing the liquid ejection head 404. 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, etc.

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

Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head 404 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 11 are formed) of the liquid ejection head 404, and a wiper member 422 that wipes the nozzle surface.

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

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

The carriage 403 is moved in the main scanning direction while the liquid ejection head 404 is driven in accordance with an image signal, thereby ejecting liquid onto the stationary paper 410 to form an image.

As such, this device is equipped with a liquid ejection head according to the present invention, allowing for the stable production of high-quality images.

Next, another example of a liquid ejection unit according to the present invention will be described with reference to Figure 15. Figure 15 is an explanatory plan view of the main parts of the unit.

This liquid ejection unit is composed of the components that make up the device that ejects the liquid: 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.

It is also possible to configure a liquid ejection unit by further attaching at least one of the aforementioned maintenance and recovery mechanism 420 and supply mechanism 494 to, for example, the side plate 491B of this liquid ejection unit.

Next, another example of a liquid ejection unit according to the present invention will be described with reference to Figure 16. Figure 16 is an explanatory front view of the unit.

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

The flow path component 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path component 444. A connector 443 is provided on the top of the flow path component 444 to electrically connect it to the liquid ejection head 404.

In this application, a "liquid ejecting device" is a device that includes a liquid ejection head or liquid ejection unit and ejects liquid by driving the liquid ejection head. Liquid ejecting devices include not only devices that can eject liquid onto objects onto 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, "liquid ejecting devices" include image forming devices that eject ink to form images 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.

Furthermore, 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.

The above phrase "something to which a liquid can adhere" refers to something to which a liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid 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 a liquid can adhere.

The above-mentioned "materials to which liquid can adhere" include paper, thread, fiber, fabric, 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.

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

Furthermore, "liquid ejection devices" include devices in which a liquid ejection head and an object onto which liquid can be attached move relatively, but are not limited to this. Specific examples include serial-type devices in which the liquid ejection head moves, and line-type devices 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.

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

Here, "integrated" includes, for example, cases in which the liquid ejection head and functional parts or mechanisms are fixed to one another by fastening, bonding, engaging, etc., or cases in which one is held movably relative to the other. The liquid ejection head, functional parts, and mechanisms may also be configured to be detachable from one another.

For example, some liquid ejection units integrate the liquid ejection head and head tank, such as liquid ejection unit 440 shown in Figure 14. Others integrate the liquid ejection head and head tank by connecting them together via a tube or the like. A unit containing a filter can also be added between the head tank and liquid ejection head of these liquid ejection units.

Also, there are 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, integrating the liquid ejection head with the scanning movement mechanism. In other liquid ejection units, as shown in Figure 15, 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.

Also, as shown in Figure 16, there is a liquid ejection unit in which a tube is connected to a liquid ejection head to which a head tank or flow path components are attached, integrating the liquid ejection head with a supply mechanism.

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

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

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

REFERENCE SIGNS LIST 1 nozzle plate 1a nozzle hole 1b liquid ejection surface 12 base layer 13 piezoelectric layer 14 protective layer 15 water-repellent film 16 first electrode 17 second electrode 20 flow path member 21 liquid chamber 24 partition wall 25 support 26 supply path 31 slit 32 elastic member 40 common liquid chamber member 71 supply port 72 cover 400 image forming apparatus 401 exterior of image forming apparatus 401c cover of apparatus main body 404 cartridge holder 410 main tank 410k, 410c, 410m, 410y main tanks for each color of black (K), cyan (C), magenta (M), and yellow (Y) 411 ink storage section 413 ink outlet 414 storage container case 420 mechanism section 434 liquid ejection head 436 Supply tube

Japanese Patent Application Laid-Open No. 2019-150069 Japanese Patent Application Laid-Open No. 2020-018288 JP 2009-126155 A

Claims (9)

a nozzle plate made of a plurality of layers including a base layer, a piezoelectric layer, a first electrode, and a second electrode;
a nozzle hole penetrating the nozzle plate;
a liquid chamber communicating with the nozzle hole,
the first electrode is provided between the base layer and the piezoelectric layer,
the second electrode is provided on the opposite side of the first electrode with the piezoelectric layer interposed therebetween,
the nozzle plate has a slit connected to the nozzle hole in a region surrounding the nozzle hole,
A liquid ejection head characterized in that the first electrode is continuous near the end of the longitudinal direction of the slit when viewed in a plane, and the second electrode is continuous near the end of the longitudinal direction of the slit when viewed in a plane. The liquid ejection head according to claim 1 , wherein the slits extend radially from the center of the nozzle hole in a plan view. 3. The liquid ejection head according to claim 1 , wherein the slit is rotationally symmetrical about the center of the nozzle hole in a plan view. 4. The liquid ejection head according to claim 1 , wherein the slit is provided in at least one of the plurality of layers having the highest Young's modulus. A liquid ejection head as described in any one of claims 1 to 4, characterized in that the slits are provided in some of the multiple layers, and when the liquid ejection surface side of the nozzle plate is the outermost surface, the slits are provided in a layer other than the outermost layer. 6. The liquid ejection head according to claim 1, wherein the slit is partially or entirely sealed with an elastic member. A liquid ejection unit comprising the liquid ejection head according to any one of claims 1 to 6 . The liquid ejection unit described in 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 the main scanning direction. 9. A liquid ejection device comprising the liquid ejection head according to claim 1 , or the liquid ejection unit according to claim 7 or 8 .