JP2020082671A - Liquid discharge head, liquid discharge unit, and liquid discharge device - Google Patents

Abstract

To prevent bending in a liquid discharge direction.SOLUTION: A liquid discharge head includes nozzles which discharge liquid. Each nozzle has: a first nozzle part (for example, an inlet part 111) having a first opening part to which the liquid is supplied; a second nozzle part (for example, an outlet part 112) which is smaller than the first opening part and a second opening part which discharges the liquid. The second nozzle part has one or more annular recessed parts (for example, a groove 17 of a first inner wall part 115) extending in an inner peripheral direction of an inner wall and has an area, at which the recessed parts do not exist, (for example, a second inner wall part 116) between the recessed parts and the second opening part.SELECTED DRAWING: Figure 15

Description

The present invention relates to a liquid ejection head, a liquid ejection unit, and a device that ejects a liquid.

In a liquid ejection head that forms an image on a medium by ejecting a liquid, a silicon substrate that has been finely processed by etching is used for the nozzle plate, and the dot density is improved compared to the conventional head, thereby achieving high definition. Techniques for realizing image quality are already known.

For example, Patent Document 1 discloses a technique of suppressing liquid ejection failure due to solid components in the liquid adhering to the irregularities on the inner wall surface of the nozzle.

However, in the conventional nozzle, the amount of bending of the discharged liquid in the direction perpendicular to the nozzle surface is large due to the axial misalignment between the outlet and the inlet of the nozzle that occurs when the nozzle plate is etched from both sides. ..

The present invention has been made in view of the above problems in the prior art, and an object thereof is to prevent bending in the liquid ejection direction.

In order to solve the above-mentioned problems, the liquid ejection head of the present invention is
Equipped with a nozzle that ejects liquid,
The nozzle is
A first nozzle portion having a first opening to which the liquid is supplied;
A second nozzle portion having a second opening portion that is smaller than the first opening portion and discharges the liquid;
The second nozzle portion has one or more annular recesses extending in the inner circumferential direction of the inner wall, and has a region where there is no recess between the recesses and the second opening. ..

According to the present invention, it is possible to prevent bending in the liquid ejection direction.

FIG. 3 is an external perspective view illustrating the liquid ejection head according to the embodiment of the present invention. It is an exploded perspective view similarly. Similarly, it is a cross-sectional perspective explanatory view. Similarly, it is a disassembled perspective explanatory view except a frame member. Similarly, it is a cross-sectional perspective explanatory view of a flow path portion. It is a plane explanatory view of a channel part similarly. FIG. 3 is a diagram illustrating an overview of a nozzle plate of a liquid ejection head according to an embodiment. It is the figure which cut out the circumference|surroundings of one nozzle of FIG. It is a figure explaining the nozzle cross section of the conventional liquid discharge head. 7 is a graph showing the relationship between the inlet diameter and the discharge bend amount at an arbitrary axis deviation G. It is a graph explaining the relationship between the inlet diameter and the discharge bending amount. It is a figure explaining the change of the symmetry of the meniscus with respect to a central axis by the increase of a straight length or an entrance diameter. It is a figure explaining an example of the water-repellent film which remained on the inner wall of a nozzle. It is a figure explaining an example of the foreign material which adhered to the nozzle inner wall. It is a figure explaining the nozzle cross section of one embodiment. It is a figure explaining an example of a section of a nozzle before a process of removing a water-repellent film adhering to a nozzle wall surface. It is a figure explaining an example of a section of a nozzle after a removal process of a water-repellent film adhering to a nozzle wall. It is a figure explaining the other shape of the nozzle cross section of one Embodiment. It is a figure explaining other shapes of a groove. FIG. 3 is a plan view of a principal part of an example of a device for ejecting a liquid according to the present invention. It is a principal part side explanatory view of the same apparatus. FIG. 3 is a plan view of an essential part of an example of a liquid ejection unit according to the present invention. It is a front explanatory view of another example of the liquid ejection unit according to the present invention.

Hereinafter, embodiments will be described with reference to the drawings. For clarity of explanation, the following description and drawings are omitted or simplified as appropriate. In each of the drawings, components and corresponding parts having the same configuration or function are designated by the same reference numerals, and the description thereof will be omitted.

First, a liquid ejection head according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is an external perspective explanatory view of a liquid ejection head according to an embodiment, FIG. 2 is an exploded perspective explanatory view thereof, and FIG. 3 is a sectional perspective explanatory view of the same. FIG. 4 is an exploded perspective explanatory view of the same except the frame member, and FIG. 5 is a sectional perspective explanatory view of the flow path portion. FIG. 6 is likewise a plan view of the flow path portion.

The liquid discharge head 1 includes a nozzle plate 10, a flow path plate (individual flow path member) 20, a diaphragm member 30, a common flow path member 50, a damper member 60, a frame member 80, and a drive circuit 102. A board (flexible wiring board) 101 on which is mounted is provided.

The nozzle plate 10 has a plurality of nozzles 11 for ejecting liquid. The plurality of nozzles 11 are arranged in a two-dimensional matrix, and as shown in FIG. 6, are arranged side by side in three directions of a first direction F, a second direction S, and a third direction T.

The individual flow channel member 20 includes a plurality of pressure chambers (individual liquid chambers) 21 that communicate with the plurality of nozzles 11, a plurality of individual supply flow channels 22 that communicate with the plurality of pressure chambers 21, and a plurality of pressure chambers 21. A plurality of individual recovery flow paths 23 that communicate with each other are formed. One pressure chamber 21 and the individual supply channel 22 and the individual recovery channel 23 that communicate with this pressure chamber 21 are collectively referred to as an individual channel 25.

The vibrating plate member 30 forms a vibrating plate 31 which is a deformable wall surface of the pressure chamber 21, and the vibrating plate 31 is integrally provided with a piezoelectric element 40. Further, the vibration plate member 30 is formed with a supply-side opening 32 that communicates with the individual supply channel 22 and a recovery-side opening 33 that communicates with the individual recovery channel 23. The piezoelectric element 40 is a pressure generating unit that deforms the vibration plate 31 to pressurize the liquid in the pressure chamber 21.

The individual flow path member 20 and the diaphragm member 30 are not limited to being separate members. For example, the individual flow path member 20 and the diaphragm member 30 can be integrally formed of the same member using an SOI (Silicon on Insulator) substrate. That is, an SOI substrate in which a silicon oxide film, a silicon layer, and a silicon oxide film are sequentially formed on a silicon substrate is used, and the silicon substrate is used as the individual flow path member 20, and the silicon oxide film, the silicon layer, and the silicon oxide film are used. The diaphragm 31 can be formed by. In this structure, the vibration plate member 30 has a layer structure of the silicon oxide film, the silicon layer, and the silicon oxide film of the SOI substrate. As described above, the diaphragm member 30 includes a member formed of the material deposited on the surface of the individual flow path member 20.

The common flow channel member 50 includes a plurality of common supply flow channel tributaries 52 that communicate with two or more individual supply flow channels 22 and a plurality of common recovery flow channel tributaries 53 that communicate with two or more individual recovery flow channels 23. Are alternately formed adjacent to each other in the second direction S.

The common flow channel member 50 includes a through hole serving as a supply port 54 through the supply side opening 32 of the individual supply flow channel 22 and the common supply flow channel tributary 52, a recovery side opening 33 of the individual recovery flow channel 23, and a common recovery flow. A through hole serving as a recovery port 55 through the branch tributary 53 is formed.

Further, the common flow channel member 50 includes one or a plurality of common supply flow channel main streams 56 that communicate with a plurality of common supply flow channel tributaries 52 and one or a plurality of common recovery channel main streams that communicate with a plurality of common recovery flow channel tributaries 53. 57 is formed.

The damper member 60 includes a supply-side damper 62 that faces (opposes) the supply port 54 of the common supply flow path tributary 52, and a recovery-side damper 63 that faces (opposes) the recovery port 55 of the common recovery flow path tributary 53. Have

Here, the common supply flow channel tributary 52 and the common recovery flow channel tributary 53 have the groove portions arranged alternately in the common flow channel member 50, which is the same member, as the supply side damper 62 or the recovery side damper 63 of the damper member 60. It is configured by sealing with. In addition, as the damper material of the damper member 60, it is preferable to use a metal thin film or an inorganic thin film that is resistant to an organic solvent. The thickness of the supply side damper 62 and the recovery side damper 63 of the damper member 60 is preferably 10 μm or less.

Next, the configuration of the liquid ejection head will be described in detail.
FIG. 7 is an overview of the nozzle plate of the liquid ejection head according to the embodiment. Further, FIG. 8 is a diagram in which the periphery of one nozzle in FIG. 7 is cut out. The nozzle plate 10 has a plurality of nozzles 11 arranged therein. FIG. 8 is a diagram in which the periphery of the nozzle surrounded by the frame P of FIG. 7 is cut out, for example.
In the following, attention is paid to the nozzle cross section (cross section cut in the nozzle plate longitudinal direction) along the line AA shown in FIG. In addition, two facing surfaces of the nozzle plate 10 in which the nozzle holes are formed are a “liquid chamber side surface” near the pressure chamber 21 and a “discharge surface” on the side where the liquid is discharged from the nozzle (“nozzle surface”). Also referred to as “)”.

[Conventional nozzle configuration]
FIG. 9 is a diagram illustrating a nozzle cross section of a conventional liquid ejection head.
The conventional liquid ejection head is formed from one silicon substrate 13. A water repellent film 15 is formed on the ejection surface of the silicon substrate 13.
The nozzle of FIG. 9 has a two-step straight structure including an inlet portion 111p and an outlet portion 112p. Both the inlet portion 111p and the outlet portion 112p are formed by etching the nozzle plate 10. The inlet portion 111p is a side where the liquid is supplied to the nozzle, that is, an inlet where the liquid enters the nozzle. The outlet 112p is a side where the liquid is ejected from the nozzle, that is, an outlet where the liquid exits from the nozzle. In the etching process, at least one annular groove is formed on the inner wall surface of the nozzle along the liquid ejection direction. The groove 17 is an annular recess extending in the inner peripheral direction of the inner wall and is also referred to as a "scallop". The groove 17 is an example of a corrugated uneven shape formed on the inner wall surface of the nozzle in the nozzle manufacturing process.

[Increase in ejection deflection due to misalignment]
The nozzle 11 is formed, for example, by etching the nozzle plate 10 from both sides of the liquid chamber side surface and the ejection surface. Therefore, the nozzle hole is formed by separately forming the inlet portion 111p and the outlet portion 112p of the nozzle plate 10 (portion of the silicon substrate 13 excluding the water-repellent film 15 of the outlet portion 112p). After the nozzle hole is formed, a deviation (axial deviation G) may occur between the central axis ax1 of the inlet portion 111p of the nozzle 11 and the central axis ax2 of the outlet portion 112p. Due to this axial misalignment G, the fluid flow becomes asymmetric with respect to the central axis ax2 of the outlet 112p in the vicinity of the boundary between the inlet 111p and the outlet 112p (concentric axis asymmetry), and the shape of the meniscus affected by this is also changed. Concentric axis asymmetry. Here, the concentric axis is the central axis ax2 of the outlet portion. FIG. 10 is a diagram illustrating the flow of fluid in the nozzle. The arrow in the inlet part 111p of FIG. 10 represents an example of a fluid flow. FIG. 10 shows an example in which the fluid flow is asymmetric with respect to the central axis ax2, and the shape of the meniscus is not symmetrical with respect to the central axis ax2 and is biased toward the central axis ax1. ing.

Due to this, the conventional liquid discharge head has a problem in that the discharge bending amount increases, and as a result, the liquid does not land at the intended location. Here, the discharge bending amount is the amount (size) of the liquid discharged from the nozzle bending in the direction perpendicular to the nozzle surface.

Therefore, the inventors have operated the inlet diameter, the outlet diameter, and the straight length (also referred to as “ST length”) shown in FIG. 9 to confirm whether or not the discharge bending amount can be suppressed. Here, the inlet diameter is the inner diameter of the inlet portion, the outlet diameter is the inner diameter of the outlet portion, and the straight length is the length of the outlet portion (the length of the outlet portion in the axial direction along the central axis ax2).
As a result, it was discovered that the discharge bending caused by the axial misalignment can be suppressed by increasing the inlet diameter or the straight length.

FIG. 11 is a graph showing the relationship between the inlet diameter and the discharge bending amount at an arbitrary axial deviation G. Further, FIG. 12 is a diagram illustrating a change in the symmetry of the meniscus with respect to the central axis ax2 due to an increase in the straight length or the entrance diameter. The nozzle cross section on the left side of FIG. 12 is an example of a conventional nozzle. The nozzle cross section on the right side of FIG. 12 is an example of a nozzle having a larger inlet diameter and a longer straight length than the left side. The arrows in the inlet portions 111p and 111s in FIG. 12 represent an example of the fluid flow.
It is considered that the reason why the bending amount of discharge is suppressed by increasing the inlet diameter is that the concentric axis symmetry of the fluid flow is improved and the concentric axis asymmetry of the meniscus is reduced by increasing the inlet diameter. ing. In addition, the reason why the discharge bending amount is suppressed by increasing the straight length is that the straight portion is lengthened so that it is near the boundary between the inlet portion 111s and the outlet portion 112s (a region where the concentric axis asymmetry of the fluid flow is high). It is believed that this is because the meniscus was moved away from.

[Increase in ejection bending amount due to existence of groove and variation between nozzles]
As described above, by increasing the inlet diameter and the straight length, it was possible to suppress the amount of ejection bending due to the amount of axial misalignment. However, it has been found that the presence of the groove 17 on the inner wall of the nozzle (the wall surface of the nozzle hole) on the nozzle surface side causes the variation in the ejection bending amount among the nozzles and the ejection bending amount itself to increase.

The cause of the variation in the ejection bending amount between nozzles is the residual water-repellent film 18 (FIG. 13) generated due to the scallop shape of the nozzle inner wall near the ejection surface, and the fluid adhered to the scallop due to the increase in viscosity. It is believed to be a foreign body 19 (FIG. 14) such as a lump.
FIG. 13 is a diagram for explaining an example of the water-repellent film remaining on the inner wall of the nozzle, and FIG. 14 is a diagram for explaining an example of foreign matter fixed on the inner wall of the nozzle.

In the structure having the groove 17 on the inner wall of the nozzle, the liquid is likely to remain in the recess, and when the meniscus is drawn into the inside of the nozzle, the liquid remaining in the recess is exposed to the outside air, and a deposit remains on the inner wall surface of the nozzle. This deposit causes the ink ejection direction to bend from the intended direction.
For example, in Patent Document 1, by devising the timing of ejection, the period of time during which the liquid remaining on the inner wall of the nozzle is exposed to the outside air is shortened, and the generation of thickened liquid around the nozzle opening is prevented. Is disclosed. However, depending on the driving method, it is feared that the generation of deposits will complicate the driving circuit.

Moreover, if a manufacturing process that does not form a scallop on the entire inner wall surface of the nozzle is adopted, the problem of deposits may be solved. However, in the case of the two or more stages of nozzles described above with reference to FIG. 9 and the like (nozzles composed of a nozzle portion having a wide diameter and a nozzle portion having a small diameter), the entire inner wall of the outlet portion 112 of the nozzle is scalloped. If there is no flat shape, the meniscus is likely to be drawn into the vicinity of the boundary between the inlet portion 111 and the outlet portion 112. When the axial deviation G exists, the flow of the liquid is asymmetric near the boundary between the inlet 111 and the outlet 112, so that the meniscus has an asymmetrical shape under the influence of the flow, which causes the liquid ejection direction to bend. ..

Therefore, the generation of deposits near the ejection surface of the inner wall surface of the nozzle and the retention of the water-repellent film are suppressed, and the meniscus asymmetry due to the asymmetry of the liquid flow near the boundary between the two nozzles is eliminated to eliminate the liquid ejection. It is desired to prevent directional bending.
Hereinafter, an embodiment according to the present invention will be described.

[Configuration of Nozzle of One Embodiment]
FIG. 15 is a diagram illustrating a nozzle cross section according to an embodiment of the present invention.
The nozzle plate 10 of one embodiment is formed from a single silicon substrate 13. A water repellent film 15 is formed on the ejection surface of the silicon substrate 13.
The nozzle has a two-stage straight structure and is composed of an inlet portion 111 as a first nozzle portion and an outlet portion 112 as a second nozzle portion. The inlet portion 111 and the outlet portion 112 are both formed by etching the nozzle plate 10. The inlet part 111 and the outlet part 112 are in communication with each other so that the fluid can flow therethrough.

The inlet portion 111 has a first opening portion 113 to which the liquid is supplied from the liquid chamber (for example, the plurality of pressure chambers 21). The first opening 113 is an opening formed on the surface of the nozzle plate 10 on the liquid chamber side, and is the end of the nozzle hole on the liquid chamber side. The size of the first opening 113 matches the size of the inlet diameter of the inlet portion 111 on the liquid chamber side.
The outlet 112 has a second opening 114 for discharging the liquid supplied to the inlet 111. The second opening 114 is an opening formed on the ejection surface of the nozzle plate 10 (ejection surface on which the water-repellent film 15 is applied), and is the end of the nozzle hole on the ejection surface side. The size of the second opening 114 matches the size of the outlet diameter of the outlet 112 on the ejection surface side.
The diameter of the first opening 113 is larger than the diameter of the second opening 114. Therefore, the nozzle 11 has a multi-stage structure including an inlet portion 111 and an outlet portion 112 having a relatively smaller diameter.

The nozzle hole is formed by an anisotropic etching method in which etching and formation of the inner wall protective film are repeated alternately. At this time, a plurality of annular recesses (grooves 17) extending in the inner peripheral direction of the inner wall are formed in the inner wall of the nozzle hole in the axial direction of the nozzle.
The inlet part 111 has a plurality of recesses on its inner wall, similar to the conventional inlet part 111p.
The outlet 112 is formed to have at least one recess. At the outlet 112, for example, the recess formed by the anisotropic etching described above is processed to change its shape. The recess of the outlet 112 will be described in detail below.

The outlet part 112 has a first inner wall part 115 and a second inner wall part 116 as two parts (regions) having different shapes on the inner wall of the nozzle.
The first inner wall portion 115 is the nozzle inlet side of the outlet portion 112 (the side closer to the inlet portion 111 of the outlet portion 112) and has a “scallop structure” in which the groove 17 is formed.
The second inner wall portion 116 is on the nozzle surface side of the outlet portion 112 and has a “non-scalloped structure” in which the groove 17 is not formed, or the groove depth is smaller than that of the first inner wall portion 115. Has a "small scallop structure" formed therein.
FIG. 15 shows an example in which the second inner wall portion 116 has a non-scallop structure.

The outlet 112 of the non-scallop structure has, for example, a region having one or more recesses on the inner wall and a recess (groove 17) between the one or more recesses and the ejection surface (second opening 114). Not have areas. The region where the recess is not present may be a region between the recess closest to the ejection surface and the ejection surface. Specifically, as shown in FIG. 15, the inner wall of the outlet 112 is preferably composed of a first inner wall 115 having a groove 17 and a second inner wall 116 having no groove 17.
The outlet 112 of the small scallop structure has, for example, two or more recesses, and the groove of the recess near the inlet 111 is deeper than the recess near the ejection surface. As for the inner wall of the outlet 112, a deep recess may be arranged in a region close to the inlet 111 side, and a relatively shallow recess may be arranged in a region from the discharge surface side boundary of the region having the deep recess to the discharge surface. Specifically, the inner wall of the outlet portion 112 preferably has a deep groove 17 formed in the first inner wall portion 115 shown in FIG. 15 and a groove shallower than the deep groove 17 in the second inner wall portion 116.

Here, the first inner wall portion 115 and the second inner wall portion 116 are arranged in the order of the inlet portion 111, the first inner wall portion 115 of the outlet portion 112, and the second inner wall portion 116 of the outlet portion 112 from the liquid chamber side. Further, it has a water repellent film 15.

By making the shape of the first inner wall portion 115 of the outlet portion 112 a scallop structure, the second inner wall portion 116 having a non-scallop structure or a small scallop structure becomes relatively easier to wet than the first inner wall portion 115. As a result, when a voltage that pulls the meniscus into the nozzle is applied to an element that generates energy for ejecting a droplet, such as the piezoelectric element 40, the position where the meniscus is stretched is separated from the boundary between the inlet portion 111 and the outlet portion 112. It is possible to prevent the meniscus from reaching near this boundary. The vicinity of the boundary between the inlet portion 111 and the outlet portion 112 is a region having a high asymmetry with respect to the axis (a region having a high asymmetry of fluid flow with respect to the central axis ax2). In this way, when the meniscus moves inside the nozzle, the movement is restricted by the scallop reaching the vicinity of the boundary between the inlet 111 and the outlet 112, and the meniscus is prevented from reaching the boundary.
As a result, even if the center axes of the inlet portion 111 and the outlet portion 112 are misaligned, the meniscus is less likely to be affected by the liquid flow near the boundary. Before and after ejection, the shape of the meniscus remains symmetrical with respect to the central axis ax2, and the ejection bending amount is suppressed.

Further, by making the shape of the second inner wall portion 116 of the outlet portion 112 a non-scallop structure or a small scallop structure, it is possible to prevent the water-repellent film from remaining. In addition, it is possible to prevent the generation of foreign matter such as a lump of liquid that sticks to the nozzle wall surface on the nozzle surface side due to the increase in viscosity.
As a result, the amount of ejection bending is suppressed. In addition, variations in the ejection bending amount between the nozzles are reduced.

[Example]
In the examples, the water repellent component (also referred to as a water repellent material or a water repellent group) attached to the inner wall of the nozzle will be described separately before and after the step of removing the water repellent film.
FIG. 16 is a diagram illustrating an example of a cross section of the nozzle before the step of removing the water repellent film attached to the nozzle wall surface.

FIG. 17 is a diagram illustrating an example of a cross section of the nozzle after the step of removing the water repellent film attached to the nozzle wall surface.
By irradiating the plasma in the plasma irradiation direction, the water repellent material is easily distributed as shown in FIGS. In the wall surface having the recess (groove), the water-repellent component is more likely to remain on the wall surface on the liquid chamber side (the inlet portion 111 side) than the wall surface on the ejection surface side in one recess. After the step of removing the water-repellent film adhering to the nozzle wall surface, the first inner wall portion 115 (scallop structure) of the outlet portion 112 has a wall surface closer to the liquid chamber than the second inner wall portion 116 (non-scallop structure or small scallop structure). The water repellent material remains on the one side.

As a result, when the meniscus near the ejection surface is drawn toward the inlet portion 111, the water repellent film on the inner wall of the nozzle of the outlet portion 112 (particularly the first inner wall portion 115) acts to further limit the movement of the meniscus. .. As a result, when the meniscus is pulled in, it becomes difficult for the meniscus to reach the vicinity of the boundary between the outlet portion 112 and the inlet portion 111 of the nozzle, so that the amount of ejection bending is suppressed. Further, the water-repellent film is less likely to act on ink filling (movement of ink from the inlet portion 111 to the ejection surface side), and the ink filling property is not impaired.

Further, since the plasma is irradiated from the inlet portion 111 side, when the first inner wall portion 115 of the outlet portion 112 has a plurality of recessed portions, the recessed portion located near the inlet portion 111 side is from the inlet portion 111 side. The water-repellent film inside is more easily removed than the concave portion on the far side. Therefore, the concave portion on the side closer to the ejection surface (the second opening 114 side) has more water-repellent components than the concave portion on the side closer to the inlet 111 side (the first opening 113 side).

[Other Embodiments]
Although FIG. 15 shows an example in which the inlet 111 has a straight structure having a straight wall surface, the present invention is not limited to this. For example, the inlet portion 111 in FIG. 15 may be an inlet portion 111a having a wall surface that is inclined with respect to the ejection surface, as shown in FIG. In the example shown in FIG. 18, since the outlet portion 112 has the non-scalloped structure in the second inner wall portion 116, the same effect as that of the embodiment described with reference to FIG. 15 and the like can be obtained. Also, the second inner wall portion 116 of the outlet portion may have a small scallop structure.

As described above, regardless of the shape (for example, the inclination) of the side wall of the inlet section 111, in the boundary surface between the inlet section 111 and the outlet section 112, in the nozzle in which the inner diameter of the inlet section 111 is larger than the inner diameter of the outlet section 112, The first inner wall portion 115 and the second inner wall portion 116 included in the outlet 112 can achieve the above-described effects. Further, by making the inlet diameter and the straight length appropriate, it is possible to suppress the discharge bending.

Further, in the above-described embodiment, the example in which the outlet 112 is composed of the two portions of the first inner wall portion 115 and the second inner wall portion 116 (regions in which the shape of the inner wall is different) has been described, but the present invention is not limited to this. is not. For example, the outlet portion may be configured to have three or more portions on the inner wall. For example, it may be configured to have an inner wall portion A having a scallop structure, an inner wall portion B having a small scallop structure, and an inner wall portion C having a non-scallop structure. At this time, the scallop structure (inner wall portion A), the small scallop structure (inner wall portion B), and the non-scallop structure (inner wall portion C) are arranged in this order from the inlet portion 111 side, and the non-scallop structure may be arranged closer to the ejection surface. .. This is because the water-repellent film is effectively prevented from remaining and the foreign matter such as a lump of liquid is prevented.

The annular recess extending in the inner peripheral direction of the inner wall of the nozzle hole may form an annular groove. However, the recess is not necessarily limited to the shape in which the grooves are connected in an annular shape, and for example, a shape in which the recess is partially removed and the groove is interrupted and filled may be present in part. The recess may be formed along the ring shape.
Further, the concave portion is not limited to the shape in which semicircles are continuously connected like the groove 17 shown in FIG. 9 and the like in cross section. For example, it may be a rectangle such as the groove 17a shown in FIG. The recess may have “grooves” along the circumferential direction of the inlet portion 111 and the outlet portion 112.

As described above, in one embodiment according to the present invention, a groove structure (for example, a scallop structure) is provided in a part of the inner wall of the nozzle, and at least another part thereof has a modified shape (small scallop structure or With the nozzle configuration having the non-scallop structure), the position of the meniscus can be limited before and after the ejection. As described above, by devising the groove structure of the inner wall of the nozzle near the ejection surface, it is possible to reduce the ejection bending amount due to the axial misalignment of the nozzle. Further, it is possible to suppress an increase in the amount of ejection bending and an increase in the variation between nozzles due to the presence of the groove on the inner wall of the nozzle.

In the present application, the liquid to be ejected is not particularly limited as long as it has a viscosity and a surface tension that can be ejected from the head, but the viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or by heating and cooling. It is preferably one. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional compounds such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids, proteins and calcium. , Solutions, suspensions, emulsions, etc. containing edible materials such as natural pigments, etc., such as ink-jet inks, surface treatment solutions, components of electronic devices and light-emitting devices, and formation of electronic circuit resist patterns. It can be used for applications such as a working fluid and a three-dimensional modeling material fluid.

Piezoelectric actuators (multilayer piezoelectric element and thin-film piezoelectric element), thermal actuators that use electrothermal conversion elements such as heating resistors, electrostatic actuators that consist of a diaphragm and counter electrode, etc. are used as the energy generation source that ejects liquid What you do is included.

Next, an example of an apparatus for ejecting a liquid according to the present invention will be described with reference to FIGS. FIG. 20 is a plan view of a main part of the apparatus, and FIG. 21 is a side view of a main part of the apparatus.

This device is a serial type device, and the carriage 403 reciprocates in the main scanning direction by a main scanning moving mechanism 493. The main scanning moving mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408 and the like. The guide member 401 is bridged between the left and right side plates 491A and 491B and movably holds the carriage 403. Then, the carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 spanning between the driving pulley 406 and the driven pulley 407.

The carriage 403 is equipped with a liquid ejection unit 440 in which the liquid ejection head 404 and the head tank 441 according to the present invention are integrated. The liquid ejection head 404 of the liquid ejection unit 440 ejects liquids of yellow (Y), cyan (C), magenta (M), and black (K), for example. Further, the liquid ejection head 404 is arranged such that a nozzle row including a plurality of nozzles 11 is arranged in a sub-scanning direction orthogonal to the main scanning direction and the ejection direction is directed downward.

The liquid stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

The supply mechanism 494 includes a cartridge holder 451, which is a filling unit for mounting the liquid cartridge 450, a tube 456, a liquid sending unit 452 including a liquid sending pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. The liquid is sent from the liquid cartridge 450 to the head tank 441 by the liquid sending unit 452 via the tube 456.

This apparatus includes a transport mechanism 495 for transporting the sheet 410. The transport mechanism 495 includes a transport belt 412, which is a transport unit, and a sub-scanning motor 416 for driving the transport belt 412.

The conveyance belt 412 adsorbs the sheet 410 and conveys it at a position facing the liquid ejection head 404. The conveyor belt 412 is an endless belt, and is stretched between a conveyor roller 413 and a tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction.

Then, the transport belt 412 is rotated in the sub-scanning direction by the sub-scanning motor 416 rotatably driving the transport roller 413 via the timing belt 417 and the timing pulley 418.

Further, on one side of the carriage 403 in the main scanning direction, a maintenance/recovery mechanism 420 for maintenance/recovery of the liquid ejection head 404 is arranged beside the transport belt 412.

The maintenance/recovery mechanism 420 includes, 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, a wiper member 422 that wipes the nozzle surface, and the like.

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

In this apparatus configured as described above, the sheet 410 is fed onto the transport belt 412 and adsorbed, and the sheet 410 is transported in the sub-scanning direction by the orbital movement of the transport belt 412.

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

As described above, since this apparatus includes the liquid ejection head according to the present invention, it is possible to stably form a high quality image.

Next, an example of the liquid ejection unit according to the present invention will be described with reference to FIG. FIG. 22 is an explanatory plan view of relevant parts of the unit.

This liquid ejection unit includes a housing portion including side plates 491A and 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid among the members forming the device that ejects the liquid. It is composed of the ejection head 404.

It is also possible to configure a liquid discharge unit in which at least one of the maintenance/recovery mechanism 420 and the supply mechanism 494 described above is further attached to, for example, the side plate 491B of this liquid discharge unit.

Next, still another example of the liquid ejection unit according to the present invention will be described with reference to FIG. FIG. 23 is a front explanatory view of the unit.

This liquid ejection unit is composed 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 arranged inside the cover 442. A head tank 441 may be included instead of the flow path component 444. Further, a connector 443 for electrically connecting with the liquid ejection head 404 is provided on the flow path component 444.

In the present application, the “device for ejecting liquid” is a device that includes a liquid ejection head or a liquid ejection unit, and drives the liquid ejection head to eject the liquid. The device for ejecting a liquid includes not only a device capable of ejecting a liquid to which a liquid can be attached, but also a device ejecting the liquid toward the air or into the liquid.

This "device for ejecting liquid" can include a means for feeding, carrying, and discharging paper to which liquid can be attached, as well as a pretreatment device, a posttreatment device, and the like.

For example, an "apparatus for ejecting a liquid" is an image forming apparatus that ejects ink to form an image on a sheet, and a powder is formed in layers to form a three-dimensional object (three-dimensional object). There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges the modeling liquid to the formed powder layer.

Further, the “device for ejecting liquid” is not limited to a device in which a significant image such as characters and figures is visualized by the ejected liquid. For example, it also includes ones that form a pattern or the like that has no meaning per se, and ones that form a three-dimensional image.

The above-mentioned "liquid can be adhered" means a liquid to which a liquid can be at least temporarily adhered, which is adhered and fixed, and which is adhered and permeated. Specific examples include recording media such as paper, recording paper, recording paper, film and cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, inspection cells and other media. Yes, and unless otherwise specified, includes anything to which liquid adheres.

The above "materials to which liquids can adhere" are temporarily liquid such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, textiles for clothing, etc. However, it is sufficient if it can be attached.

The “liquid” also includes ink, treatment liquid, DNA sample, resist, pattern material, binder, modeling liquid, or solution and dispersion liquid containing amino acid, protein, calcium.

Further, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can be attached move relatively, but the device is not limited to this. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as the "apparatus for ejecting liquid", a treatment liquid application device for ejecting the treatment liquid onto the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, raw materials, etc. There is an injection granulating device for spraying a composition liquid in which the above is dispersed in a solution through a nozzle to granulate fine particles of a raw material.

The “liquid ejection unit” is a unit in which functional components and mechanisms are integrated with a liquid ejection head, and is a collection of components related to liquid ejection. For example, the “liquid ejection unit” includes a combination of a liquid ejection head with at least one of the configurations of a head tank, a carriage, a supply mechanism, a maintenance/recovery mechanism, and a main scanning movement mechanism.

Here, the term "integral" means, for example, a liquid discharge head, a functional component, and a mechanism that are fixed to each other by fastening, bonding, engaging, or the like, or one that is movably held with respect to the other. Including. Further, the liquid ejection head, the functional component, and the mechanism may be configured to be detachable from each other.

For example, as a liquid ejection unit, there is one in which a liquid ejection head and a head tank are integrated, like the liquid ejection unit 440 shown in FIG. In addition, there is one in which the liquid ejection head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter may be added between the head tank and the liquid ejection head of these liquid ejection units.

Further, as a liquid ejection unit, there is one in which a liquid ejection head and a carriage are integrated.

Further, as a liquid ejection unit, there is a unit in which a liquid ejection head and a scanning movement mechanism are integrated so that a liquid ejection head is movably held by a guide member forming a part of the scanning movement mechanism. Further, as shown in FIG. 22, there is a liquid ejection unit in which a liquid ejection head, a carriage, and a main scanning movement mechanism are integrated.

Further, as a liquid ejection unit, there is a unit in which a cap member that is a part of a maintenance/recovery mechanism is fixed to a carriage to which a liquid ejection head is attached, and the liquid ejection head, the carriage, and the maintenance/recovery mechanism are integrated. ..

Further, as a liquid ejection unit, as shown in FIG. 23, there is one in which a tube is connected to a liquid ejection head to which a head tank or a flow path component is attached, and the liquid ejection head and the supply mechanism are integrated. ..

The main scanning movement mechanism includes a single guide member. The supply mechanism also includes a tube unit and a loading unit unit.

Further, the “liquid ejection head” is not limited to the pressure generating means used. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, a vibration plate and a counter electrode are used. An electrostatic actuator or the like may be used.

Further, in the terms of the present application, image formation, recording, printing, printing, printing, modeling, etc. are synonymous.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. There is no end.

1 Liquid Ejection Head 10 Nozzle Plate 11 Nozzle 13 Silicon Substrate 15 Water Repellent Film 17, 17a Grooves 111, 111a, 111p, 111s Inlet 112, 112p, 112s Outlet 113 First Opening 114 Second Opening 115 First Inner Wall Part 116 Second inner wall part

JP, 2017-14912, A

Claims (8)

Equipped with a nozzle that ejects liquid,
The nozzle is
A first nozzle portion having a first opening to which the liquid is supplied;
A second nozzle portion having a second opening portion that is smaller than the first opening portion and discharges the liquid;
The second nozzle portion has one or more annular recesses extending in the inner circumferential direction of the inner wall, and has a region where there is no recess between the recesses and the second opening. Liquid ejection head. Equipped with a nozzle that ejects liquid,
The nozzle is
A first nozzle portion having a first opening to which the liquid is supplied;
A second nozzle portion having a second opening portion that is smaller than the first opening portion and discharges the liquid;
The second nozzle portion has two or more annular recesses extending in the inner peripheral direction of the inner wall,
A liquid discharge head, wherein a recess near the first nozzle portion is deeper than a recess near the second opening. The second nozzle portion is
A first inner wall portion near the first nozzle portion;
A second inner wall portion between the first inner wall portion and the second opening portion,
The first inner wall portion has the recess,
The said 2nd inner wall part has either the inner wall which has a recessed part whose groove is shallower than the said recessed part which the said 1st inner wall part has, and the inner wall which does not have a recessed part, The 1 or 2 characterized by the above-mentioned. Liquid ejection head. 4. The liquid ejection head according to claim 3, wherein a water repellent component is contained more on the surface of the first nozzle portion side than in the second opening portion inside the concave portion of the first inner wall portion. . A plurality of the recesses are formed in the first inner wall portion along the axial direction of the nozzle,
The liquid ejection head according to claim 3, wherein the concave portion on the side closer to the second opening has a larger amount of water-repellent component than the concave portion on the side closer to the first opening. The liquid ejection head according to claim 1, wherein the substrate forming the nozzle is made of silicon. A liquid ejecting unit comprising the liquid ejecting head according to claim 1. An apparatus for ejecting a liquid, comprising the liquid ejection head according to any one of claims 1 to 6 or the liquid ejection unit according to claim 7.