JP2023135592A - Liquid discharge head and liquid discharge device - Google Patents

Abstract

To join an elastic member to a core material of an on-off valve with an elastic function maintained.SOLUTION: A liquid discharge head includes an on-off valve 31 which opens or closes a discharge port. The on-off valve 31 has: a core material 310 provided with a recessed part 312 which is open to the discharge port side; and an elastic member 40 which is fitted in the recessed part 312 and partially protrudes from the recessed part 312 to the discharge port side. The recessed part 312 has a removal prevention part 50 whose width increases toward a bottom surface 312a in a half area d2 at the bottom surface side in a depth direction B.SELECTED DRAWING: Figure 5

Description

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

2. Description of the Related Art As a liquid discharging device, a valve-type nozzle type liquid discharging device is known, in which a discharge port (nozzle) for discharging liquid is opened and closed by an on-off valve.

For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2020-23117) discloses an on-off valve in which an elastic member is provided at the tip of a core material that constitutes the on-off valve.

In the case of a structure in which an elastic member is provided at the tip of the on-off valve, it is necessary to join the core material and the elastic member. Bonding using an adhesive may be considered as one of the bonding means, but bonding may be difficult depending on the material of the elastic member. In addition, mechanical joining means such as crimping is available as a joining means in place of adhesion, but in the case of joining by crimping, the elastic member may be restrained at the joining location, which may impair the elastic function. Therefore, there is a need for a joining means that can maintain elastic function.

In order to solve the above problems, the present invention provides a liquid ejection head that includes an ejection port that ejects liquid and an on-off valve that opens and closes the ejection port, the on-off valve opening toward the ejection port side. The recess has a core material provided with a recess, and an elastic member that fits into the recess and partially projects from the recess toward the discharge port, and the recess has a core material in a half area on the bottom side in the depth direction. , is characterized by having a retaining portion whose width increases toward the bottom surface.

According to the present invention, the elastic member can be joined to the core material of the on-off valve while maintaining its elastic function.

1 is an external perspective view of a liquid ejection head according to an embodiment of the present invention. 1 is an overall sectional view of a liquid ejection head according to an embodiment of the present invention. FIG. 3 is a diagram showing the position of a heater provided in a liquid ejection head. FIG. 3 is a cross-sectional view of a liquid ejection head. FIG. 3 is a cross-sectional view showing the configuration of the front end side of the on-off valve. It is a sectional view showing a state where a core material and a sealing member are separated. FIG. 3 is a diagram showing the relationship between displacement (pushing amount) and load of the on-off valve according to the embodiment of the present invention. It is a figure which shows an example of arrangement|positioning of a retaining part. It is a figure which shows another example of arrangement|positioning of a retaining part. FIG. 7 is a cross-sectional view showing a modification of the recess. It is a sectional view showing a modification of a sealing member. FIG. 12 is a sectional view showing a state in which the seal member shown in FIG. 11 is inserted into a recess. It is a figure which shows the other modification of a recessed part. FIG. 14 is a sectional view showing a state in which the core material and seal member shown in FIG. 13 are separated. FIG. 14 is a diagram showing a state in which the on-off valve shown in FIG. 13 is pressed against a nozzle plate. It is a figure which shows yet another modification of a recessed part. It is a figure which shows the other example of a combination of a recessed part and a sealing member. It is a figure which shows yet another example of a combination of a recessed part and a sealing member. FIG. 3 is a diagram showing an example in which the core material is divided into two parts. It is a figure which shows yet another modification of a recessed part. 21 is a diagram showing a state in which a seal member is inserted into the recess shown in FIG. 20. FIG. FIG. 1 is an overall schematic configuration diagram of a liquid ejection device. FIG. 3 is an overall schematic configuration diagram of another liquid ejection device. FIG. 2 is a perspective view showing an example of the arrangement of a liquid ejection device in an automobile. FIG. 7 is a perspective view showing another example of the arrangement of the liquid ejection device in the automobile. FIG. 3 is an explanatory diagram when a liquid is ejected onto a spherical surface by a liquid ejecting device. FIG. 3 is a cross-sectional view showing the configuration of the front end side of an on-off valve according to a comparative example. FIG. 7 is a sectional view showing a separated state of a core material and a seal member according to a comparative example. FIG. 7 is a cross-sectional view showing a state before a core material and a seal member are crimped and joined according to a comparative example. FIG. 7 is a cross-sectional view showing a state in which an on-off valve according to a comparative example is pressed against a nozzle plate. FIG. 2 is a diagram showing the configuration of a test device. FIG. 7 is a diagram showing the relationship between displacement (pushing amount) and load of an on-off valve according to a comparative example. FIG. 3 is a diagram showing the relationship between the position (displacement) of an on-off valve and the amount of ink ejected.

Hereinafter, the present invention will be explained based on the accompanying drawings. In addition, in each drawing for explaining the present invention, components such as members and components having the same function or shape are given the same reference numerals as much as possible so that they can be distinguished. Omitted.

FIG. 1 is an explanatory diagram of the external appearance of a liquid ejection head according to an embodiment of the present invention. FIG. 1(a) is an overall perspective view of the liquid ejection head, and FIG. 1(b) is an overall side view of the head. The liquid ejection head according to this embodiment ejects ink as liquid.

The liquid ejection head 10 includes a first housing 11a as a first casing and a second housing 11b as a second casing. The second housing 11b is stacked and joined to the first housing 11a. The first housing 11a is made of a highly thermally conductive material such as metal, and the second housing 11b may be made of a different material from the first housing 11a, but is preferably made of the same material. In the following description, when the two housings are collectively referred to as housing 11.

Further, the first housing 11a is provided with a heater 12 as a heating means on its front and back surfaces. The heater 12 can be temperature controlled and heats the first housing 11a. Further, the second housing 11b includes a connector 13 for communicating electrical signals on its upper part.

FIG. 2 is an overall sectional view of the liquid ejection head 10 according to the embodiment of the present invention, and is a sectional view taken along the line AA in FIG. 1(a). The first housing 11a holds a nozzle plate 15 as a discharge port forming member. The nozzle plate 15 includes a nozzle 14 as a discharge port that discharges liquid. The first housing 11a also includes a flow path 17 that is a liquid supply section. The flow path 17 sends ink from the supply port 16 side to the recovery port 18 side via the nozzle plate 15.

The second housing 11b includes a supply port 16 and a recovery port 18. The supply port 16 and the recovery port 18 are connected to one side and the other side of the flow path 17, respectively. A plurality of liquid ejection modules 30 are arranged between the supply port 16 and the recovery port 18. The liquid ejection module 30 ejects ink within the flow path 17 from the nozzle 14 . Furthermore, a regulating member 20 is provided above the liquid ejection module 30.

The liquid discharge modules 30 correspond to the number of nozzles 14 provided in the first housing 11a, and in this example, the configuration includes eight liquid discharge modules 30 corresponding to the eight nozzles 14 arranged in one row. It is shown. Note that the number and arrangement of the nozzles 14 and liquid ejection modules 30 are not limited to the above. For example, the number of nozzles 14 and liquid ejection modules 30 may be one instead of a plurality. Furthermore, the nozzles 14 and the liquid ejection modules 30 may be arranged in multiple rows instead of one row.

Note that in FIG. 2, reference numeral 19 is a housing seal member provided at the joint between the first housing 11a and the second housing 11b. In this example, an O-ring is used as the housing seal member, and the O-ring prevents ink from leaking from the joint between the first housing 11a and the second housing 11b.

With the above configuration, the supply port 16 takes in pressurized ink from the outside, sends the ink in the direction of arrow a1, and supplies the ink to the flow path 17. The flow path 17 sends ink from the supply port 16 in the direction of arrow a2. The recovery port 18 then recovers ink that has not been ejected from the nozzles 14 arranged along the flow path 17 in the direction of arrow a3.

The liquid discharge module 30 includes an on-off valve 31 and a piezoelectric element 32 as a driver. The on-off valve 31 opens and closes the nozzle 14. The piezoelectric element 32 drives the on-off valve 31. Moreover, the piezoelectric element 32 expands and contracts in the longitudinal direction, which is the vertical direction in FIG. 2, by applying a voltage.

In the above configuration, when the piezoelectric element 32 is activated and the on-off valve 31 is moved upward, the nozzle 14, which had been closed by the on-off valve 31, is opened, and ink cannot be ejected from the nozzle 14. can. Furthermore, when the piezoelectric element 32 is activated and the on-off valve 31 is moved downward, the tip of the on-off valve 31 seals the nozzle 14 and the nozzle 14 is closed, and ink flows out from the nozzle 14. It stops spitting out.

FIG. 3 is an explanatory diagram showing the positional relationship between the liquid ejection head 10 and the heating means according to the embodiment of the present invention. The first housing 11a includes a heater 12. As shown by the broken line in FIG. 3, the heater 12 is provided near the nozzles 14 so as to cross the plurality of nozzles 14.

Next, details of the liquid ejection module 30 will be explained based on FIG. 4. FIG. 4(a) is a sectional view of a single liquid ejection module, and FIG. 4(b) is an enlarged view of the main part of FIG. 4(a). Two O-rings 34 are attached to the outer periphery of the shaft of the on-off valve 31 in order to prevent leakage of high-pressure ink.

The liquid discharge module 30 mainly includes the aforementioned on-off valve 31, piezoelectric element 32, fixing member 33, holder 35, plug 36, and the like.

The holder 35 has a driver accommodating portion 35a therein, and accommodates and holds the piezoelectric element 32 in the driver accommodating portion 35a. The holder 35 is made of metal that can be elastically expanded and contracted in the longitudinal direction of the piezoelectric element 32. As the elastically expandable metal, stainless steel such as SUS304 or SUS316L can be used, for example. The holding body 35 is a frame body in which a plurality of elongated members extending in the longitudinal direction are arranged around the piezoelectric element 32 (for example, four pieces are arranged at 90° intervals), and the piezoelectric element 32 constitutes the holding body 35. It is inserted inside the holder 35 through the elongated members.

The longitudinal direction of the piezoelectric element 32 is the double arrow direction A shown in FIG. 4(a), and this longitudinal direction A is also the longitudinal direction of the on-off valve 31, the liquid discharge module 30, and the second housing 11b. Moreover, the longitudinal direction A is also the moving direction of the on-off valve 31.

An on-off valve 31 is connected to the tip of the holder 35 on the nozzle 14 side. Furthermore, a bellows portion 35b is formed on the nozzle 14 side of the holder 35. The bellows portion 35b is for causing the distal end side of the holder 35 to expand and contract in the longitudinal direction in the same manner as the piezoelectric element 32 when the piezoelectric element 32 expands and contracts.

Further, a fixing member 33 is connected to the base end side of the holder 35, which is the side opposite to the nozzle 14 side. In other words, the fixing member 33 is housed in the upper end of the second housing 11b.

The fixing member 33 has a through screw hole 33a extending in the radial direction. A positioning screw 60 is screwed into the through-screw hole 33a from outside the second housing 11b.

The positioning screw 60 is inserted into a longitudinally elongated hole 11b1 formed at the upper end of the second housing 11b. Therefore, the positioning screw 60 is movable by a predetermined length in the longitudinal direction of the second housing 11b. The positioning screw 60 is tightened with the fixing member 33 positioned in the longitudinal direction.

As shown in FIG. 4(a), a female screw hole 11b2 is formed in the upper end opening of the second housing 11b. A plug 36 that comes into contact with the regulating member 20 in FIG. 2 is screwed into this female threaded hole 11b2. The plug 36 comes into contact with the upper end of the fixing member 33 that is positioned in the longitudinal direction by the positioning screw 60, and finally fixes the fixing member 33 in position.

Furthermore, a compression spring 37 is disposed at the lower end of the second housing 11b. This compression spring 37 urges the piezoelectric element 32 and the holder 35 holding the piezoelectric element 32 upward.

As shown in FIG. 4(b), the on-off valve 31 includes a core material 310 and a seal member 40. The core material 310 is formed of a metal material such as stainless steel. A recess 312 that opens toward the nozzle 14 is provided at the end of the core material 310 on the nozzle 14 side. The sealing member 40 can be made of, for example, a fluororesin such as PTFE (polytetrafluoroethylene) or PCTFE (polychlorotrifluoroethylene), or an elastic member such as rubber. It is preferable to use PTFE with a tensile modulus of 0.40 GPa or more and 0.60 GPa or less, and PCTFE with a tensile modulus of 1.03 GPa or more and 2.10 GPa or less. The value of tensile modulus can be determined by performing ISO527: Plastics-Determination of tensile properties or JISK7161: Plastics-tensile properties test. By fitting into the recess 312 of the core material 310, it is attached to the tip (end on the nozzle 14 side) of the core material 310. Further, a portion of the seal member 40 protrudes from the recess 312 of the core material 310 toward the nozzle 14 side. Therefore, when the piezoelectric element 32 is activated and the on-off valve 31 is moved downward in FIG. The nozzle 14 is sealed by the sealing member 40. Conversely, when the on-off valve 31 is moved upward, the seal member 40 is separated from the nozzle plate 15 and the nozzle 14 is opened. In this way, the on-off valve 31 moves between the position where the seal member 40 (elastic member) is pressed against the nozzle plate 15 (discharge port forming member) and the position where it is spaced apart from the nozzle plate 15, so that the nozzle 14 ( (discharge port) is opened and closed.

In the liquid discharge module 30 according to the present embodiment, the on-off valve 31 includes the core material 310 and the seal member 40 attached to the tip of the core material 310, so that the seal member 40 is separated from the core material 310. Both parts must be joined to prevent them from coming apart. As a joining means, for example, adhesive bonding is available, but if the seal member 40 is formed of a material that is difficult to adhere to, such as a fluororesin, bonding by adhesive is difficult. Further, as another joining method, there is a method of crimping the tip of the core material 310 and mechanically joining the sealing member 40, but the method of crimping the tip of the core material 310 has the following problems. .

FIG. 27 is an enlarged cross-sectional view of the on-off valve 31 that employs a crimped joint structure.

In the configuration shown in FIG. 27, the seal member 40 is restrained by crimping the tip of the core member 310 from the state shown by the broken line to the state shown by the solid line in the figure, and the seal member 40 is prevented from falling out of the recess 312. Prevented. However, in this case, elastic deformation (particularly elastic deformation in the depth direction B of the recess 312) is restricted because the seal member 40 is restrained at a relatively distal end side portion (the caulking location). Therefore, a good elastic function of the sealing member 40 cannot be obtained.

Further, when the sealing member 40 is formed by punching a sheet-like member, the width of the sealing member 40 is wider at the middle part in the vertical direction than at the upper and lower ends in the figure as shown in FIG. They tend to be formed into smaller shapes. In the case of such a seal member 40, when the seal member 40 is inserted into the recess 312, a gap is generated between the seal member 40 and the side surface 312b of the recess 312, as shown in FIG. Furthermore, when the tip of the core material 310 is crimped from this state, the sealing member 40 is deformed by the crimping, and the gap between the sealing member 40 and the side surface 312b of the recess 312 becomes larger, and the sealing member 40 A gap also occurs between the concave portion 312 and the bottom surface 312a. As a result, the adhesion of the seal member 40 within the recess 312 decreases, and the posture of the seal member 40 becomes unstable. Therefore, as shown in FIG. 30, when the seal member 40 is pressed against the nozzle plate 15, the seal member 40 retreats from the state shown by the broken line to the state shown by the solid line in the figure. As a result, the desired pressing force of the sealing member 40 against the nozzle plate 15 cannot be obtained, and the sealing performance deteriorates.

Here, a test was conducted to examine the elastic function of the seal member 40 in the crimped joint valve as described above. In this test, a sealing member 40 with a tip diameter of 500 μm was joined to the core material 310 of the on-off valve 31 by caulking, and the on-off valve 31 was attached to a testing machine, and a crystal piezoelectric tool power source shown in FIG. 31 was used. The sealing member 40 was pushed in 1 μm at a time for a total of 10 μm to apply pressure to a total of 80 parts. Thereafter, the sealing member 40 was moved back by 1 μm to reduce the pressure and remove the load. In addition, the displacement (pushing amount) and load of the on-off valve 31 were measured during pressurization (forward movement) and pressure reduction (backward movement). FIG. 32 shows the relationship between the measured displacement and load.

In FIG. 32, the solid line shows the displacement load curve of the on-off valve 31 when pressurizing, and the broken line shows the displacement load curve of the on-off valve 31 when the pressure is reduced. As shown in FIG. 32, when the load at the start of pressurization was 0 [N], the displacement was 0 [μm], whereas at the time of unloading, the displacement was about 5 [μm]. This is because when the seal member 40 is pressed against the tool dynamometer 80, the seal member 40 retreats into the recess 312 and is displaced, so that even when the load is removed, the tip of the seal member 40 remains at its original position ( It is thought that it did not return to the position before pressurization, but retreated by about 5 [μm]. Therefore, although the elastic modulus (first-order coefficient) of the sealing member 40 is originally about 1 [N/μm], the apparent elastic modulus of the sealing member 40 decreases and becomes lower than 1 [N/μm]. It became as small as 0.4 [N/μm].

In this manner, in the crimped joint valve, the distal end side of the seal member 40 is restrained, thereby limiting elastic deformation, and the seal member 40 retreats into the recess 312 when pressurized, thereby reducing the apparent appearance. Since the elastic modulus decreases, the seal member 40 is no longer able to exhibit the desired elastic function. Moreover, such a decline in elastic function is not constant and is affected by variations in crimping. Therefore, in order to ensure sealing performance, it is necessary to perform the following position adjustment for each on-off valve 31 depending on the degree of decline in the elastic function of the seal member 40.

FIG. 33 is a diagram showing the relationship between the position (displacement) of the on-off valve 31 and the amount of ink ejected from the nozzle 14. (a) to (d) in FIG. 33(e) show the respective discharge amounts when the on-off valve 31 is arranged at each position shown in (a) to (d) in the figure.

In the state shown in FIG. 33(a), the tip of the on-off valve 31 (seal member 40) is at the farthest position from the nozzle 14. At this time, the amount of ink ejected is maximum. Then, as shown in FIG. 33(b), as the tip of the on-off valve 31 approaches the nozzle 14, the amount of ink ejected decreases. Further, when the tip of the on-off valve 31 approaches the nozzle 14 and the seal member 40 comes into contact with the nozzle plate 15 as shown in FIG. 33(c), the amount of ink ejected becomes almost zero. However, the nozzle 14 is not completely sealed in this state. In order to completely seal the nozzle 14, it is necessary to press the tip (sealing member 40) of the on-off valve 31 against the nozzle plate 15 to compress the sealing member 40, as shown in FIG. 33(d). .

However, when the tip of the on-off valve 31 is pressed against the nozzle plate 15, if the seal member 40 retreats into the recess 312 as described above, the amount of compression of the seal member 40 cannot be secured sufficiently, so the nozzle 14 It becomes impossible to seal. Therefore, it is necessary to shift the reference position (initial position) of the on-off valve 31 in the forward direction by the distance that the seal member 40 retreats so that a sufficient amount of compression of the seal member 40 can be obtained.

However, if the reference position of the on-off valve 31 is shifted in the forward direction, since the amount of expansion and contraction of the piezoelectric element is constant (for example, about 20 μm to 30 μm), the position of the on-off valve 31 when the nozzle 14 is open is Change. When the nozzle 14 is open, it is necessary to ensure a sufficient gap (for example, 5 μm or more) between the sealing member 40 and the nozzle 14 in order to obtain a predetermined amount of ink discharge. Therefore, when adjusting the position of the on-off valve 31, management is necessary to ensure a sufficient gap between the seal member 40 and the nozzle 14 when the nozzle is opened, and to ensure a sufficient amount of compression of the seal member 40 when the nozzle is closed. Is required. It is difficult to balance the positions of the on-off valve 31 when the nozzle is open and when the nozzle is closed, and a lot of effort and time are spent on adjustment work. Therefore, an object of the present invention is to improve the problem caused by the deterioration of the elastic function of the sealing member in order to facilitate the position adjustment work of the on-off valve.

Hereinafter, a joint structure of a seal member according to the present invention will be described using the embodiment shown in FIG. 5 as an example.

As shown in FIG. 5, in this embodiment, a retaining portion 50 is provided in the recess 312 of the core material 310 to prevent the seal member 40 from falling off. The retaining portion 50 is a portion where the concave portion 312 is formed to have a wide width. The "width" here means the size of the recess 312 in the direction C perpendicular to the depth direction B. Note that "width" in the following description also has the same meaning.

The retaining portion 50 is provided on the bottom surface 312a side of the recess 312. In particular, in this embodiment, the retaining portion 50 is provided adjacent to the bottom surface 312a. Further, a protrusion 61 having a triangular cross section is provided on the bottom surface 312a. The protrusion 61 is provided at the center of the bottom surface 312a, and protrudes from the bottom surface 312a toward the opening side of the recess 312 (downward in FIG. 5).

FIG. 6 shows a state in which the core material 310 and the seal member 40 are separated.

As shown in FIG. 6, the seal member 40 separated from the core material 310 is formed in a cylindrical shape, and is formed in a shape different from the shape of the recess 312. As shown in FIG. When the sealing member 40 having such a shape is inserted into the recess 312, the distal end surface of the sealing member 40 in the insertion direction is pressed against the protrusion 61 provided in the recess 312, thereby being pushed wider in the width direction. As a result, a portion of the sealing member 40 (the expanded portion) is filled into the retaining portion 50, and the sealing member 40 is fitted into the retaining portion 50 (see FIG. 5).

As described above, in this embodiment, by inserting the seal member 40 into the recess 312, a part of the seal member 40 fits into the retaining part 50, so that the seal member 40 is prevented from falling out of the recess 312. is joined to. Therefore, in this embodiment, the seal member 40 can be joined without crimping the tip of the core material 310, and various problems associated with crimping as described above can be solved.

That is, in the case of this embodiment, since the distal end side portion of the seal member 40 is not crimped, the seal member 40 is not constrained at the distal end side, and elastic deformation of the seal member 40 is allowed. Further, since the occurrence of a gap in the recess 312 and the expansion of the gap due to the seal member 40 being crimped are reduced, the posture of the seal member 40 is stabilized, and the seal member 40 is pushed into the recess 312 when pressurized. The setback is also reduced. This also suppresses the apparent decrease in elastic modulus due to the seal member 40 retreating into the recess 312.

Here, in the present embodiment, the retaining portion 50 is provided adjacent to the bottom surface 312a of the recess 312, but on the contrary, the retaining portion 50 may be provided on the opening side of the recess 312. Due to the fitting between the sealing member 40 and the retaining portion 50, there is a possibility that the elastic deformation of the sealing member 40 (particularly the elastic deformation in the depth direction B of the recess 312) may be restricted on the distal end side thereof. Regarding this point, in the present embodiment, as shown in FIG. 5, the retaining portion 50 is provided in the bottom half region d2 in the depth direction B of the recess 312, so that the sealing member 40 is Not constrained on the tip side. That is, in the present embodiment, elastic deformation of the seal member 40 is allowed on the distal end side, so that the elastic function of the seal member 40 on the distal end side can be ensured well, and the seal member 40 can be pressed against the nozzle plate 15. It is possible to secure a sufficient amount of compression when

As described above, in this embodiment, the elastic function of the sealing member 40 is ensured well and a sufficient amount of compression is obtained, so that the nozzle 14 can be sealed well and reliably. Furthermore, in this embodiment, the retreat of the seal member 40 into the recess 312 when the seal member 40 is pressed against the nozzle plate 15 can be reduced, making it easier to adjust the position of the on-off valve 31. Therefore, according to the configuration of this embodiment, it is possible to easily adjust the ink ejection amount (the position of the on-off valve), and to provide a highly reliable liquid ejection head with excellent sealing performance and bonding performance.

FIG. 7 is a diagram showing the relationship between the displacement (pushing amount) of the on-off valve 31 and the load in the embodiment of the present invention. In FIG. 7, the solid line shows the displacement load curve of the on-off valve 31 when pressurizing, and the broken line shows the displacement load curve of the on-off valve 31 when the pressure is reduced. Furthermore, the test method conducted to investigate this relationship was the same as the above test.

As shown in FIG. 7, in this embodiment, the displacement load curve (solid line) of the on-off valve 31 when pressurizing (when moving forward) and the displacement load curve (broken line) of the on-off valve 31 when depressurizing (when moving backward) ), and there was almost no change in the position of the seal member tip between the start of pressurization and the time of unloading. From this result, it was found that in this embodiment, the retreat of the seal member 40 into the recess 312 was reduced, and the seal member 40 was able to exhibit a good elastic function. From the above, it can be said that according to the configuration (joining structure) of this embodiment, it is possible to ensure good sealing performance of the seal member 40 and improve workability in position adjustment.

In this embodiment, the retaining portion 50 is provided adjacent to the bottom surface 312a, but the retaining portion 50 does not necessarily need to be adjacent to the bottom surface 312a as long as the region d2 is half of the bottom surface side. . Further, the shape of the retaining portion 50 is not limited to a rectangular cross-sectional shape as shown in FIG. 5, but may be a triangular or semicircular cross-sectional shape. In short, the retaining portion 50 may have a shape in which the width increases rapidly toward the bottom surface 312a, or may have a shape in which the width increases smoothly. Note that from the viewpoint of ensuring better retaining function, the retaining part 50 has a shape in which the width increases at a right angle or an angle close to the depth direction B of the recess 312 (for example, as shown in FIG. 5). Preferably, the shape is as shown. Further, the retaining portion 50 may be provided continuously over the entire circumferential direction E centering on the center of the bottom surface 312a, as in the example shown in FIG. It may be provided in a part of the circumferential direction E, as in the example shown in FIG.

Next, a modification of the on-off valve 31 will be described. In the following description, parts that are different from the above embodiment will be mainly described, and since the other parts have basically the same configuration, the description will be omitted as appropriate.

In the modification shown in FIG. 10, the shape of the protrusion 61 provided in the recess 312 is different from the above embodiment. In the above embodiment, the protrusion 61 is formed in a conical or pyramidal shape with a triangular cross section (see FIG. 5), but in the example shown in FIG. 10, the protrusion 61 is formed in a hemispherical or spherical shape. There is. In this way, even when the protrusion 61 has a hemispherical or spherical shape, the protrusion 61 can function as a filling auxiliary part that spreads the sealing member 40 in the width direction and fills it into the retaining part 50. Further, the protrusion 61 may have other shapes (cylindrical, prismatic, etc.).

FIG. 11 is a diagram showing a modification of the seal member 40. As shown in FIG.

In the embodiment described above, the sealing member 40 is formed into a columnar shape with a uniform width (see FIG. 6), but the sealing member 40 shown in FIG. It is formed so that the width becomes smaller toward the sides. As described above, in the case of punching, the sealing member 40 tends to be formed in such a shape.

When the seal member 40 having such a shape is inserted into the recess 312, a gap may occur between the side surface 312b of the recess 312 and the seal member 40, as shown in FIG. In this case, although the adhesion of the seal member 40 to the recess 312 is reduced, there may be some gap between the side surface 312b of the recess 312 and the seal member 40.

That is, in this case as well, since the joining structure by crimping is not used, it is possible to avoid limiting the elastic deformation of the sealing member 40 and expanding the gap between the sealing member 40 and the recess 312 due to crimping. The elastic function of the sealing member 40 can be ensured favorably. Further, since the seal member 40 is less likely to retreat into the recess 312 when the seal member 40 is pressed against the nozzle plate 15, it becomes easier to adjust the position of the on-off valve 31. Therefore, in this case as well, it can be expected that good sealing performance of the seal member 40 will be ensured and that the workability of position adjustment will be improved.

Next, in the example shown in FIGS. 13 and 14, the shapes of both the recess 312 and the seal member 40 are different from the above embodiment. Specifically, in the example shown in FIGS. 13 and 14, the width of the concave portion 312 is formed to gradually increase toward the opening edge 312c, and the retaining portion 50 is formed to have a triangular cross section. . On the other hand, the seal member 40 is formed so that its width gradually decreases toward its tip side (nozzle side).

In this way, the retaining portion 50 may be formed to have a triangular cross section. Further, the inside of the recess 312 is formed so that the width thereof gradually increases toward the opening edge 312c, and conversely, the seal member 40 is formed such that the width gradually decreases toward the distal end thereof. A gap is formed between the seal member 40 and the side surface 312b of the recess 312 at the opening edge 312c of the recess 312 and in the vicinity thereof (see FIG. 13). Therefore, in the example shown in FIG. 13, when the tip of the seal member 40 is pressed against the nozzle plate 15 as shown in FIG. It can be deformed following the inclination of the nozzle plate 15. That is, since the distal end portion of the seal member 40 is not restrained by the side surface 312b of the recess 312, the seal member 40 is allowed to deform in accordance with the inclination of the nozzle plate 15.

As a result, when the sealing member 40 is pressed against the nozzle plate 15, it is possible to prevent excessive load from being applied to the nozzle plate 15, and to prevent problems such as bending of the ink ejection direction due to deformation of the nozzle plate 15. It can be avoided. Further, since the adhesion of the seal member 40 to the nozzle plate 15 can be ensured, good sealing performance can be obtained. Furthermore, since a sufficient gap between the sealing member 40 and the nozzle 14 when the nozzle is opened can be ensured, a predetermined amount of ink can also be ejected.

Further, a gap (a gap between the seal member 40 and the side surface 312b of the recess 312) that allows deformation on the distal end side of the seal member 40 is at least a region d1 on the opening side of the recess 312 that includes the opening edge 312c. In this case, it is only necessary to provide the seal member 40 between the side surface 312b of the recess 312 and the seal member 40 (see FIG. 13).

In the examples shown in FIGS. 13 and 14, the width of the recess 312 gradually increases toward the opening edge 312c, but as in the example shown in FIG. 16, the width of the recess 312 increases stepwise. You can do it like this. Further, as in the example shown in FIG. 17, the width of the seal member 40 may be uniform as long as the width of the recess 312 is formed to gradually increase toward the opening edge 312c. On the other hand, if the width of the sealing member 40 is formed to become smaller toward the tip side (nozzle side) as in the example shown in FIG. It may be uniform. That is, if a gap can be formed between the seal member 40 and the side surface 312b of the recess 312 in the opening-side half region d1 of the recess 312 that includes at least the opening edge 312c, the width can be increased or decreased because of the difference between the recess 312 and the seal. Only one of the members 40 may be used.

Further, as in the example shown in FIG. 19, the core material 310 may be divided into two along the bottom surface 312a of the recess 312. In this case, the retaining portion 50 can be processed from the bottom surface 312a side of the recess 312, making it easier to process the retaining portion 50.

Further, as in the example shown in FIG. 20, the retaining portion 50 may be configured by a plurality of grooves 62 that are continuously provided in the depth direction B of the recessed portion 312. In this case, when the seal member 40 is inserted into the recess 312, a part of the seal member 40 is filled in the groove 62, as shown in FIG. It is joined like this. Furthermore, since the groove 62 as the retaining portion 50 is provided in the region d2 of the bottom half of the recess 312 in the depth direction B, the elastic function of the sealing member 40 on the distal end side can be improved as in the above embodiment. can be ensured in good condition. Therefore, also in this example, the seal member 40 can be joined to the core material 310 of the on-off valve 31 while maintaining the elastic function of the seal member 40. Note that the groove 62 may be a plurality of annular grooves formed independently of each other, or may be a single spiral groove formed continuously. Further, the shape of the groove 62 may be a triangular cross section as shown in FIG. 20, or a rectangular cross section or a semicircular cross section.

Furthermore, in the example shown in FIG. 20, a straight portion 63 in which the groove 62 is not formed is provided between the groove 62 and the bottom surface 312a. The straight portion 63 is a cylindrical surface extending in a direction (depth direction B) orthogonal to the bottom surface 312a. Therefore, in the straight portion 63, the width of the recessed portion 312 does not change over the depth direction B and is formed to have the same size. In this way, since the straight portion 63 is provided between the groove 62 and the bottom surface 312a, it is not necessary to cut the groove 62 to a position adjacent to the bottom surface 312a, so that the formation of the groove 62 is facilitated. It can be carried out.

Next, a liquid ejection apparatus including the liquid ejection head 10 described above will be described.

FIG. 22 is an overall schematic configuration diagram of the liquid ejection device 100. FIG. 22(a) is a side view of the liquid ejecting device, and FIG. 22(b) is a plan view of the device. The liquid ejecting device 100 is installed facing a liquid application target 500, which is an example of a target. The liquid ejection device 100 includes an X-axis rail 101, a Y-axis rail 102 that intersects with the X-axis rail 101, and a Z-axis rail 103 that intersects with the X-axis rail 101 and the Y-axis rail 102. In particular, in this embodiment, each rail 101, 102, 103 extends in directions orthogonal to each other.

The Y-axis rail 102 holds the X-axis rail 101 so that the X-axis rail 101 can move in the Y-axis direction. Further, the X-axis rail 101 holds the Z-axis rail 103 so that the Z-axis rail 103 can move in the X-axis direction. The Z-axis rail 103 holds the carriage 1 so that the carriage 1 can move in the Z-axis direction.

The liquid ejection device 100 includes a first Z-direction drive unit 92 that moves the carriage 1 in the Z-axis direction along the Z-axis rail 103, and a first Z-direction drive unit 92 that moves the Z-axis rail 103 in the X-axis direction along the X-axis rail 101. A drive section 72 is provided. The liquid ejection device 100 also includes a Y-direction drive unit 82 that moves the X-axis rail 101 in the Y-axis direction along the Y-axis rail 102. Furthermore, the liquid ejecting device 100 includes a second Z-direction driving section 93 that moves the head holder 70 in the Z-axis direction with respect to the carriage 1.

The liquid ejection head described above is attached to the head holder 70 so that the nozzle 14 (see FIG. 2) of the liquid ejection head 10 faces the liquid application target 500. The liquid ejection device 100 configured as described above ejects liquid from the liquid ejection head attached to the head holder 70 toward the liquid application target 500 while moving the carriage 1 in the X-axis, Y-axis, and Z-axis directions. For example, ink is ejected to draw on the liquid application target 500.

Next, the configuration of an inkjet printer 201, which is another example of a liquid ejection device, will be described with reference to FIGS. 23 to 26. FIG. 23 is a configuration diagram showing the configuration of an inkjet printer 201 as an example of a liquid ejection device according to this embodiment. FIG. 24 is an explanatory diagram showing an example of the arrangement of the inkjet printer 201 shown in FIG. 23 with respect to the automobile M that is the printing target. FIG. 25 is an explanatory diagram showing another arrangement example of the inkjet printer 201 shown in FIG. 23 with respect to the automobile M to which the liquid is applied. FIG. 26 is an explanatory diagram when an image is printed on a spherical surface using an inkjet printer. FIG. 26(a) is an explanatory diagram when an image is printed on a spherical surface by the inkjet printer 201, FIG. 26(b) is an explanatory diagram showing the result when a rectangle is printed on a spherical surface, and FIG. 26(c) is an explanatory diagram showing the result when a rectangle is printed on a spherical surface. FIG. 3 is an explanatory diagram when rectangles are successively printed on a spherical surface by an inkjet printer 201. FIG.

As shown in FIG. 23, the inkjet printer 201 according to this embodiment includes a print head 202, an XY table 203, a camera 204, a control section 209, a drive section 211, and the like.

The print head 202 is an inkjet type liquid ejection head that ejects ink (liquid) toward the surface of the object M to be painted. Note that the term "ink" here also includes "paint." The print head 202 includes a plurality of valve-shaped nozzles, and ink is ejected from each valve-shaped nozzle in a direction perpendicular to the ejection surface of the print head 202. That is, the ink ejection surface of the print head 202 is parallel to the XY plane formed by the movement of the XY table 203, and the ink dots ejected from each valve nozzle are perpendicular to the XY plane. discharged in the direction. Furthermore, the ink ejected from each valve-shaped nozzle is ejected in parallel directions. Each valve-shaped nozzle is connected to an ink tank of a predetermined color. In addition, since the ink tank is pressurized by the pressure device, if the distance between each valve-shaped nozzle and the printing target surface of the object M is about 20 cm, ink dots can be drawn from each valve-shaped nozzle without any problem. It can be ejected onto the surface to be printed.

The XY table 203 includes a mechanism for moving the print head 202 and camera 204 in the X and Y directions that are orthogonal to each other. Specifically, the XY table 203 includes an X-axis moving mechanism 205 that moves a slider holding a print head 202 and a camera 204 (described later) in the X direction, and a Y-axis moving mechanism 205 that holds the X-axis moving mechanism 205 with two arms. A Y-axis moving mechanism 206 for moving in the direction is provided. The Y-axis moving mechanism 206 is provided with a shaft 207, and a robot arm 208 holds and drives the shaft 207 to move the print head 202 to a predetermined position on the object M to be printed. can be placed freely. For example, if the object M to be painted is a car, the robot arm 208 can position the print head 202 on top of the car as shown in FIG. 24 or on the side of the car as shown in FIG. 25. Note that the operation of the robot arm 208 is controlled based on a program stored in the control unit 209 in advance.

The camera 204 is an imaging means such as a digital camera that photographs the surface of the object M to be printed. The camera 204 is moved in the X direction and the Y direction by an X-axis moving mechanism 205 and a Y-axis moving mechanism 206, and photographs a predetermined range of the print target surface of the object M at constant minute intervals. Specifications such as the lens and resolution of the camera 204 are appropriately selected so that a plurality of subdivided images can be captured for a predetermined range of the print target surface. The camera 204 captures a plurality of subdivided images of the print target surface continuously and automatically by a control unit 209, which will be described later.

The control unit 209 operates the XY table 203 based on the image editing software S that edits the image photographed by the camera 204 and a preset control program to perform the printing operation (ink ejection operation) of the print head 202. control. The control unit 209 is composed of a so-called microcomputer, and includes a storage device that records and stores various programs and data of images to be printed as well as data of images that have been photographed, a central processing unit that executes various processes according to the programs, It is equipped with input devices such as a keyboard and mouse, and a DVD player if necessary. Further, the control unit 209 includes a monitor 210. The monitor 210 displays input information to the control unit 209, processing results by the control unit 209, and the like.

The control unit 209 performs image processing on the plurality of subdivided image data captured by the camera 204 using image processing software, and converts the non-flat printing target surface of the object M into a composite printing surface projected onto the flat surface. generate. The control unit 209 also superimposes the image to be drawn, which is printed so as to be continuous with the image already printed on the surface to be printed, on the composite print surface, so that the image to be drawn is continuous with the edge of the printed image. Perform editing to generate an edited image to be drawn. For example, regarding the print image 252b that is the drawing target image shown in FIG. By editing, an edited image to be drawn is generated. Then, ink is ejected from the print head 202 onto the printing target surface based on the generated drawing target editing image, so that the new image is printed without creating a gap between it and the already printed image. Note that the photographing of a plurality of subdivided images by the camera 204 and the printing operation by ejecting ink from each nozzle of the print head 202 are performed by a driving unit 211 whose operation is controlled by a control unit 209 .

In FIG. 26(a), when a two-dimensional square is formed by an inkjet nozzle on the spherical surface of a liquid application target 251 of a spherical object, the inkjet nozzles mounted on the nozzle head 250 eject liquid. The direction of ink ejection is illustrated. In FIG. 26(b), since the ink ejected from each inkjet nozzle mounted on the nozzle head 250 is ejected in a direction perpendicular to the nozzle head 250, the print image printed on the surface of the liquid application target 251 is It is shown that 252a is a rectangle with a distorted periphery.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

In the present invention, a "liquid ejection device" is a device that includes a liquid ejection head and drives the liquid ejection head to eject liquid. Liquid ejecting devices include not only devices that can eject liquid onto objects to which liquid can adhere, but also devices that eject liquid into air or liquid.

Furthermore, the "liquid ejecting device" may include means for feeding, transporting, and discharging objects to which liquid can adhere, as well as pre-processing devices, post-processing devices, and the like.

For example, "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and liquid ejecting devices that eject ink to form images on paper. There is a three-dimensional modeling device (three-dimensional modeling device) that discharges a modeling liquid onto a body layer.

Further, the "liquid ejecting device" is not limited to one in which significant images such as characters and figures can be visualized by ejected liquid. For example, it includes things that form patterns that have no meaning in themselves, and things that create three-dimensional images.

The above-mentioned "object to which liquid can adhere" refers to the above-mentioned object to which liquid can be applied, such as to which liquid can adhere at least temporarily, to which it adheres and sticks, to which it adheres and penetrates, etc. means. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic components such as electronic boards, piezoelectric elements, powder layers, organ models, and test cells. Unless otherwise specified, it includes everything to which liquid can adhere.

Further, the material of "the material to which liquid can adhere" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc., as long as the liquid can adhere even temporarily.

Furthermore, the term "liquid ejection apparatus" includes a device in which a liquid ejection head and an object to which liquid can be attached move relative to each other, but the present invention is not limited thereto. Specific examples include a serial type device that moves a liquid ejection head, a line type device that does not move a liquid ejection head, and the like.

In addition, "liquid ejecting devices" include processing liquid coating devices that eject processing liquid onto paper in order to coat the surface of the paper with the purpose of modifying the surface of the paper, etc. There is an injection granulation device that granulates fine particles of a raw material by injecting a composition liquid dispersed therein through a nozzle.

To summarize the aspects of the present invention described above, the present invention includes a liquid ejection head and a liquid ejection device having at least the following configurations.

[First configuration]
A first configuration is a liquid ejection head that includes an ejection port that ejects liquid and an on-off valve that opens and closes the ejection port, and the on-off valve has a core provided with a recess that opens toward the ejection port. and an elastic member that fits into the recess and partially protrudes from the recess toward the discharge port, and the recess extends toward the bottom in a half area on the bottom side in the depth direction. This is a liquid ejection head that has a retaining portion that has a larger width.

[Second configuration]
In a second configuration, in the first configuration, the elastic member is a liquid ejection head filled in the retaining portion.

[Third configuration]
In a third configuration, in the first or second configuration, the retaining portion is a liquid ejection head provided adjacent to the bottom surface.

[Fourth configuration]
In a fourth configuration, in any one of the first to third configurations, the recess is a liquid ejection head having a protrusion provided on the bottom surface.

[Fifth configuration]
A fifth configuration is a liquid ejection head in which, in any one of the first to fourth configurations, a gap is provided between at least the opening edge of the recess and the elastic member.

[Sixth configuration]
A sixth configuration is a liquid ejection head in which, in the fifth configuration, the recessed portion increases in width toward the edge of the opening.

[Seventh configuration]
A seventh configuration is a liquid ejection head in which the width of the elastic member decreases toward the ejection port side in the fifth or sixth structure.

[Eighth configuration]
An eighth configuration is a liquid ejection head in which in the first or second configuration, the recess has a straight portion extending in a direction perpendicular to the bottom surface between the retaining portion and the bottom surface. .

[Ninth configuration]
A ninth configuration, in any one of the first to eighth configurations, includes a discharge port forming member in which the discharge port is formed, and the opening/closing valve pushes the elastic member against the discharge port forming member. The liquid ejection head opens and closes the ejection port by moving between a contact position and a position spaced apart from the ejection port forming member.

[Tenth configuration]
A tenth configuration is a liquid ejection apparatus including a liquid ejection head having any one of the first to ninth configurations.

10 Liquid discharge head 14 Nozzle (discharge port)
31 Open/close valve 40 Seal member (elastic member)
50 Retaining part 61 Protrusion 63 Straight part 310 Core material 312 Recessed part 312a Bottom surface 312b Side surface 312c Opening edge B Depth direction d1 Opening side half area d2 Bottom side half area

JP2020-23117A

Claims (10)

a discharge port for discharging liquid;
an on-off valve that opens and closes the discharge port;
A liquid ejection head comprising:
The on-off valve includes a core member provided with a recess that opens toward the discharge port, and an elastic member that fits into the recess and partially projects from the recess toward the discharge port,
The liquid ejection head is characterized in that the concave portion has a retaining portion whose width increases toward the bottom surface in a half region on the bottom surface side in the depth direction. The liquid ejection head according to claim 1, wherein the elastic member is filled in the retaining portion. 3. The liquid ejection head according to claim 1, wherein the retaining portion is provided adjacent to the bottom surface. 3. The liquid ejection head according to claim 1, wherein the recess has a protrusion provided on the bottom surface. The liquid ejection head according to claim 1 or 2, wherein a gap is provided between at least an opening edge of the recess and the elastic member. The liquid ejection head according to claim 5, wherein the width of the recessed portion increases toward the edge of the opening. 6. The liquid ejection head according to claim 5, wherein the width of the elastic member decreases toward the ejection port. 3. The liquid ejection head according to claim 1, wherein the recess has a straight portion extending in a direction perpendicular to the bottom surface between the retaining portion and the bottom surface. comprising a discharge port forming member in which the discharge port is formed;
3. The opening/closing valve opens and closes the discharge port by moving the elastic member between a position where the elastic member is pressed against the discharge port forming member and a position where the elastic member is spaced apart from the discharge port forming member. Liquid ejection head. A liquid ejection device comprising the liquid ejection head according to claim 1 or 2.

Images