JP7737628B2 - Liquid ejection head, liquid ejection unit, and liquid ejection device - Google Patents

Description

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

Conventionally, liquid ejection heads have been known that include internal components and exterior components that cover the internal components.

Patent Document 1 describes a liquid ejection head that includes internal components such as liquid supply paths and liquid chambers, as well as an exterior cover member that covers electrical components such as a circuit board.

However, there was a risk of distortion occurring in at least one of the exterior and interior parts.

In order to solve the above-mentioned problems, the present invention provides a device comprising an internal component and an exterior component covering the internal component, wherein the internal component is joined to one side and the other side of the exterior component that face each other via the internal component, wherein the internal component comprises a first member and a second member connected to the first member so as to be movable relative to the first member in a direction perpendicular to a joining surface at which the internal component is joined to the exterior component, and wherein the device has a second internal component fixed to the second member and a member different from the second member, and wherein the internal component has a third member connected to the second member so as to be movable relative to the second member in a direction perpendicular to the joining surface .

This invention can prevent distortion from occurring in exterior and interior components.

FIG. 1 is a schematic cross-sectional view of a liquid ejection head according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of a flow path component of the liquid ejection head. 1A is a schematic cross-sectional view showing an exterior cover and flow path components of a conventional liquid ejection head, and FIG. 1B is a schematic cross-sectional view showing the exterior cover and flow path components of the conventional liquid ejection head after thermal expansion. 10A and 10B are diagrams showing an example of distortion after thermal expansion of a conventional liquid ejection head. 1A is a schematic cross-sectional view showing an exterior cover and flow path components of a liquid ejection head according to the present embodiment, and FIG. 1B is a schematic cross-sectional view showing the exterior cover and flow path components of the liquid ejection head after thermal expansion. FIG. 10 is a schematic cross-sectional view of a liquid ejection head in which a flow path component and an exterior cover are joined with an adhesive. FIG. 10 is a schematic cross-sectional view of a liquid ejection head in which a sealing member is provided at a joint portion. FIG. 10 is a schematic cross-sectional view showing a first modified example of the flow path component. FIG. 10 is a schematic cross-sectional view showing a second modified example of the flow path component. FIG. 10 is a schematic cross-sectional view showing a second modified example in which an electrical board is fixed to a head unit and a lower liquid supply unit. 10A and 10B are diagrams illustrating a problem in which the connection between the lower liquid supply unit and the upper liquid supply unit comes off when the upper liquid supply unit is joined to the exterior cover. 10 is a schematic cross-sectional view showing an embodiment of a second modified example in which a first detachment prevention portion and a second detachment prevention portion are provided. FIG. FIG. FIG. FIG. FIG.

Hereinafter, an embodiment in which the present invention is applied to a liquid ejection head of an inkjet recording apparatus as an image forming apparatus that ejects liquid will be described.
The present invention is not limited to the embodiments shown below, but can be modified, added, modified, deleted, etc., within the scope of what a person skilled in the art can conceive, and any aspect is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

FIG. 1 is a schematic cross-sectional view of a liquid ejection head 1 according to this embodiment, and FIG. 3 is a schematic perspective view of a flow path part 3. As shown in FIG.
The liquid ejection head 1 includes a flow path component 3 as an internal component, an electrical board 4 as a second internal component, and an exterior cover 2 as an exterior component that covers these components.

The flow path component 3 has a head portion 3a as a first member and a liquid supply portion 3b as a second member. The liquid supply portion 3b is connected to the head portion 3a by a connecting portion 10 so as to be movable in the up and down direction relative to the head portion 3a.
The head unit 3a has a nozzle surface 31 on which a plurality of nozzles 31a are arranged, individual liquid chambers to which the nozzles 31a communicate, a common liquid chamber that supplies liquid to the individual liquid chambers, a pressure unit that pressurizes the liquid in each individual liquid chamber, etc. Four nozzle rows are provided in a direction perpendicular to the plane of the paper in FIG.

The liquid supply unit 3b includes a supply path leading to the common liquid chamber of the head unit 3a, a supply port 32 that penetrates the exterior cover 2 and to which a tube for supplying liquid from a tank that stores the liquid is detachably connected. The outer surface of the supply port 32 is barbed to prevent the attached tube from coming loose. As shown in Figure 3, four supply ports 32 are arranged on the top surface of the flow path component 3.

Liquid supplied to the supply port 32 is supplied from the supply path of the liquid supply unit 3b via the connecting unit 10 to the common liquid chamber of the head unit 3a, and then from the common liquid chamber to the individual liquid chambers. The color of the liquid supplied from one of the two supply ports is different from the color of the liquid supplied from the other supply port. The liquid supplied from one supply port is ejected from the nozzles of one of the two nozzle rows, and the liquid supplied from the other supply port is ejected from the nozzles of the other nozzle row.

The connecting portion 10, which connects the head portion 3a and the liquid supply portion 3b, is composed of a cylindrical connecting insertion portion 35 that protrudes from the upper surface of the head portion 3a, and a circular connecting recess 34 that is provided on the lower surface of the liquid supply portion 3b and into which the connecting insertion portion 35 of the head portion 3a is inserted. A communication passage that leads to the common liquid chamber is formed in the center of the connecting insertion portion 35, and a supply path is connected to the bottom surface of the connecting recess 34.

The inner diameter of the connecting recess 34 is larger than the outer diameter of the connecting insertion portion 35, and an O-ring 33 is provided as a sealing member that fills the gap between the inner surface of the connecting recess 34 and the outer surface of the connecting insertion portion 35. This O-ring 33 seals the liquid that flows from the supply path of the liquid supply portion 3b to the connecting recess 34, preventing liquid leakage. The liquid that flows into the connecting recess 34 flows through the communication passage of the connecting insertion portion 35 to the common liquid chamber.

It is preferable to provide a groove on the inner surface of the connecting recess 34 or the connecting insertion portion 35 into which the O-ring 33 fits. This allows the O-ring 33 to be fitted into either the connecting recess 34 or the connecting insertion portion 35, and the connecting insertion portion 35 to be inserted into the connecting recess 34, making assembly easier.

It is also preferable to make the upper surface of the connecting insertion part 35 a tapered surface that slopes downward toward the connecting passage provided in the center of the connecting insertion part 35. This allows liquid adhering to the upper surface of the connecting insertion part 35 to flow into the connecting passage without flowing down from the supply path of the connecting recess 34 into the connecting passage in the center of the connecting insertion part 35.

It is also preferable to provide a connecting recess 34 in the head portion 3a and a connecting insertion portion 35 in the liquid supply portion 3b. By providing the connecting recess 34 in the head portion 3a, the sealing point of the O-ring 33 can be located above the point where liquid is transferred from the supply path of the liquid supply portion 3b to the communication path of the head portion 3a. This prevents liquid from flowing down into the sealing point of the O-ring 33, improving the liquid sealing performance.

In this embodiment, the connecting portion 10 has a connecting recess 34 and a connecting insertion portion 35 that is inserted into this connecting recess 34, and the connecting insertion portion 35 is configured to be movable within a predetermined range within the connecting recess 34. This allows the liquid supply portion 3b to be connected to the head portion 3a so that it can move relative to the head portion 3a.

The electrical board 4, which serves as a second internal component, is connected to an actuator provided in the pressure section of the head portion 3a and has a drive circuit formed thereon to drive the actuator. An FFC (flexible flat cable) 5 is connected to the electrical board 4 to transmit power and drive signals from the outside to the electrical board 4. The electrical board 4 is located adjacent to the side of the head portion 3a and is secured to the bottom surface of the exterior cover 2 with screws 6. The electrical board 4 may also be fixed to the head portion 3a. Fixing the electrical board 4 to the head portion 3a prevents the electrical board 4 from interfering with thermal expansion of the head portion 3a in the left-right direction in the figure.

The exterior cover 2 comprises a box-shaped first cover member 2a that is open at the bottom, and a plate-shaped second cover member 2b that is joined to the first cover member 2a with screws 6 to close the opening of the first cover member 2a.

The second cover member 2b, which forms the bottom of the exterior cover 2, has an opening 21a formed therein to expose the nozzle surface 31 of the head portion 3a. The top surface of the first cover member 2a, which forms the ceiling of the exterior cover 2, has an opening 21b formed therein for the supply port 32 of the liquid supply portion 3b to pass through, and an opening 21c formed therein for the FFC 5 to pass through.

As shown in FIG. 1, the lower surface (joining surface) of the flow path component 3 is joined to the exterior cover 2 with screws 6 near the opening 21a for exposing the nozzles 31a of the nozzle surface 31, and the lower surface of the flow path component 3 is tightly attached to the bottom surface (joining surface) of the exterior cover 2. This prevents droplets, dust, dirt, etc. from entering the exterior cover through the opening 21a. Additionally, the upper surface (joining surface) of the flow path component 3 is joined to the exterior cover with screws 6 near the opening 21b for the supply port 32 to pass through, and the upper surface of the flow path component 3 is tightly attached to the ceiling surface (joining surface) of the exterior cover 2. This prevents droplets, dust, dirt, etc. from entering the exterior cover through the opening 21b. This prevents droplets, dust, dirt, etc. from adhering to the electrical board 4 placed inside the exterior cover, thereby preventing the occurrence of short circuits, etc.

The exterior cover 2 is made of PPS (polyphenylene sulfide) containing glass filler, as it requires both aesthetic appeal and strength. Meanwhile, the flow path components 3 (head portion 3a and liquid supply portion 3b) are required to be liquid-wettable and clean, as well as low-cost and resistant to chemical attack by ink, and are therefore made of PP (polypropylene) containing no glass filler. In this way, the exterior cover 2 and flow path components 3 are made of different materials to meet the required conditions. As a result, the flow path component 3 has a higher linear expansion coefficient in high-temperature environments, and the height fluctuation of the flow path component 3 is greater than the height fluctuation of the exterior cover 2 in high-temperature environments.

FIG. 3(a) is a schematic cross-sectional view showing an exterior cover and flow path components of a conventional liquid ejection head, and (b) is a schematic cross-sectional view showing the exterior cover and flow path components of a conventional liquid ejection head after thermal expansion.
As shown in FIG. 3( a), in a flow path component of a conventional liquid ejection head, a liquid supply section 3 b is fixed to the upper surface of a head section 3 a with an adhesive or the like, and the liquid supply section 3 b is connected so as not to be able to move relative to the head section 3 a.
In the conventional liquid ejection head, the lower surface of the flow path part 3 is joined to the exterior cover with screws 6 near the opening 21a for exposing the nozzle surface, and the lower surface of the flow path part 3 is brought into close contact with the bottom surface of the exterior cover 2. Therefore, the height from the lower surface, which is the joining surface of the flow path part 3 joined to the exterior cover, to the upper surface is the same as the height from the bottom surface, which is the joining surface of the exterior cover, to the ceiling surface.

As shown in Figure 3(b), the exterior cover 2 made of PPS containing glass filler undergoes a thermal expansion change in the height between the joined surfaces (height from the bottom to the ceiling) from D to D' under high-temperature conditions. On the other hand, the flow path component 3 made of PP, which has a higher linear expansion coefficient than the exterior cover 2, undergoes a thermal expansion change in the height between the joined surfaces (height from the bottom to the top) from D to D'' (D' < D'') under high-temperature conditions. Thus, the flow path component 3 experiences greater dimensional fluctuation due to thermal expansion than the exterior cover 2. However, the flow path component 3, whose top and bottom surfaces are joined to the exterior cover 2 and housed therein, has its dimensional fluctuation suppressed by the exterior cover 2 at the joining points around the openings 21a and 21b. As a result, as shown in Figure 4, the upper and lower surfaces of the exterior cover 2 and the flow path component 3 both distort, protruding from the center in the horizontal direction in the figure. This distortion of the flow path component 3 distorts the nozzle surface 31, preventing liquid ejected from the nozzle from landing at the specified position. Furthermore, distortion of the liquid ejection head 1 as shown in Figure 4 results in poor appearance. Furthermore, if the flow path component 3 is bonded to the exterior cover 2 with an adhesive, distortion as shown in Figure 3 may cause the adhesive to come off, resulting in the flow path component 3 rattling inside the exterior cover 2.

Figure 5(a) is a schematic cross-sectional view showing the outer cover 2 and flow path components 3 of the liquid ejection head of this embodiment, and Figure 5(b) is a schematic cross-sectional view showing the outer cover and flow path components of the liquid ejection head after thermal expansion.
As shown in FIG. 5A, in the flow path part 3 of this embodiment, the liquid supply part 3b is connected to the head part 3a so as to be movable in the up and down direction relative to the head part 3a.

As shown in Figure 5(a), in this embodiment, when the height from the lower surface, which is the joining surface of the flow path part 3 joined to the exterior cover 2, to the upper surface is the same as the height D from the bottom surface, which is the joined surface of the exterior cover, to the ceiling surface, a gap d is formed between the upper surface of the head part 3a and the lower surface of the liquid supply part 3b. In other words, in this embodiment, a gap d is formed between the upper surface of the head part 3a and the lower surface of the liquid supply part 3b, and the lower and upper surfaces of the flow path part 3 are joined to the exterior cover, allowing the flow path part 3 to be housed within the exterior cover.

As shown in Figure 5(b), the height between the joined surfaces (height from the bottom to the ceiling) of the exterior cover 2 changes from D to D' due to thermal expansion, as in the conventional case. Meanwhile, the flow path component 3 attempts to thermally expand in the height direction by (D''-D') more than the exterior cover 2. However, because it is actually held down by the exterior cover 2, the height between the joined surfaces of the flow path component 3 (height from the bottom to the top) is held down to D'. The excess thermal expansion of the flow path component 3 (D''-D') is absorbed by the gap d between the top surface of the head portion 3a and the bottom surface of the liquid supply portion 3b narrowing to d'. As a result, stress is suppressed at the joint between the exterior cover 2 and the flow path component 3 in high-temperature environments, and distortion of the liquid ejection head 1 in high-temperature environments is suppressed. This prevents the impact position from shifting from the specified position and poor appearance in high-temperature environments.

While the above describes a case where the linear expansion coefficient of the flow path component 3 is greater than that of the exterior cover 2, the configuration of this embodiment can also be applied when the linear expansion coefficient of the flow path component 3 is smaller than that of the exterior cover 2. When the linear expansion coefficient of the flow path component 3 is smaller than that of the exterior cover 2, the conventional configuration shown in FIG. 3 results in the liquid ejection head 1 distorting into a concave shape at the top and bottom, contrary to the configuration shown in FIG. 4. On the other hand, in this embodiment, the liquid supply portion 3b of the flow path component 3 is configured to be movable vertically relative to the head portion 3a. This allows the liquid supply portion 3b to move relative to the head portion 3a during thermal expansion, widening the gap d between the head portion 3a and the liquid supply portion 3b. This prevents stress from occurring at the joint between the exterior cover 2 and the flow path component 3 in high-temperature environments, thereby preventing distortion of the liquid ejection head 1 in high-temperature environments. If the linear expansion coefficient of the flow path component 3 is smaller than that of the exterior cover 2, there does not need to be any gap d between the head portion 3a and the liquid supply portion 3b (d = 0) initially (at room temperature).

Furthermore, for example, manufacturing errors may cause a difference in the height dimension between the joined surfaces of the exterior cover 2 (height from the bottom surface to the ceiling surface) and the height dimension between the joined surfaces of the flow path component 3 (height from the bottom surface to the top surface). In such cases, the conventional configuration shown in Figure 3 would result in distortion of the exterior cover 2 and flow path component 3, as shown in Figure 4. However, in this embodiment, such dimensional differences due to manufacturing errors can be absorbed by the liquid supply unit 3b moving vertically relative to the head unit 3a, and distortion of the exterior cover 2 and flow path component 3 due to dimensional differences between the exterior cover and head unit caused by manufacturing errors can also be suppressed.

In the above description, the flow path part 3 is joined to the exterior cover 2 by the screws 6, but as shown in FIG. 6, the flow path part 3 may be joined to the exterior cover 2 by an adhesive 7 as a sealant.
When the exterior cover 2 and the flow path part 3 are joined with the screws 6, a small gap may be generated between the exterior cover 2 and the flow path part 3. Therefore, there is a risk that droplets adhering to the part of the flow path part 3 exposed from the opening 21b of the exterior cover 2 may eventually enter the exterior cover 2 through the small gap at the joined part.

6, by joining the exterior cover 2 and the flow path component 3 with adhesive 7, it is possible to completely seal the gap at the joined portion and prevent liquid from entering the exterior cover 2 through the joined portion. Also, by joining the first cover member 2a and the second cover member 2b with adhesive 7 as well, it is possible to prevent liquid from entering the exterior cover through the gap between the first cover member 2a and the second cover member 2b.
Furthermore, as shown in FIG. 6, by filling the opening 21c of the exterior cover 2 through which the FFC 5 passes with adhesive 7, it is possible to prevent the intrusion of droplets, dust, etc. through this opening 21c.

On the other hand, as shown in Figure 1, joining the exterior cover 2 and the flow path component 3 with screws 6 offers the following advantages. Specifically, the inner diameter of the through hole through which the screw 6 passes in the exterior cover 2 is made larger than the outer diameter of the body of the screw 6, and the gap between the through hole and the body of the screw can absorb any lateral dimensional errors between the flow path component 3 and the exterior cover 2 that occur during thermal expansion. This has the advantage of reducing the shear stress applied to the joint in a high-temperature environment compared to joining the exterior cover 2 and the flow path component 3 with adhesive 7. Furthermore, the gap between the through hole in the exterior cover 2 and the body of the screw is blocked by the head of the screw, preventing the intrusion of liquids, dust, etc. through the gap.

Furthermore, bonding using adhesive 7 has the property of shrinking when hardened, depending on the adhesive 7, and variations in this shrinkage may cause distortion in the flow path component 3 or the exterior cover 2, or lead to poor bonding. In contrast, joining the exterior cover 2 and flow path component 3 with screws 6 has the advantage of preventing the above-mentioned distortion and poor bonding that occur when bonding using adhesive 7.

Also, as shown in Figure 7, a sealing member 8 made of an elastic material such as rubber may be provided as a sealant at the joint between the exterior cover 2 and the flow path component 3, and the exterior cover 2 and the flow path component 3 may be joined with screws 6. This configuration also completely seals the gap at the joint, preventing liquid from entering the exterior cover 2 through the joint.

The sealing member may be any material that fills the gap between the exterior cover 2 and the flow path component 3 at the joint, and may be adhesive 7. Joining the exterior cover 2 and the flow path component 3 with adhesive and screws 6 can prevent the above-mentioned problems caused by shrinkage of the adhesive when it hardens.

In addition, by providing a sealing member 8 at the fixed location between the first cover member 2a and the second cover member 2b and joining them with screws 6, it is possible to prevent liquid from entering the exterior cover through the gap between the first cover member 2a and the second cover member 2b.

In the above description, the flow path component 3 is fixed to the exterior cover 2 with adhesive 7 and screws 6, and the flow path component 3 is joined to the exterior cover 2. However, it is sufficient that the flow path component 3 contacts the exterior cover 2 in a manner that prevents the intrusion of droplets, dust, and the like into the exterior cover through the openings 21a and 21b. Therefore, if high adhesion can be achieved, the flow path component 3 may be joined to the exterior cover 2 simply by contacting the flow path component 3 with the periphery of the openings 21a and 21b of the exterior cover 2, without fixing with adhesive 7 or screws 6. In cases where the linear expansion coefficient of the flow path component 3 is greater than the linear expansion coefficient of the exterior cover 2, as in this embodiment, the connection between the flow path component 3 and the exterior cover 2 is maintained, and the liquid supply portion 3b of the flow path component 3 can be moved relative to the head portion 3a, thereby suppressing distortion of the flow path component 3 and the exterior cover 2.

On the other hand, if the linear expansion coefficient of the flow path component 3 is smaller than that of the exterior cover 2, it is preferable to join the flow path component 3 to the exterior cover 2 by fixing them together with adhesive 7 or screws 6. This is because if the flow path component 3 is joined simply by contacting it with the periphery of the openings 21a and 21b of the exterior cover 2, the bond cannot be maintained in a high-temperature environment, and a gap will form between the flow path component 3 and the exterior cover 2. As a result, it will not be possible to prevent liquids and the like from entering the exterior cover.

In a configuration where the linear expansion coefficient of the flow path component 3 is smaller than that of the exterior cover 2 and they are joined by screws 6 or the like, when a difference in thermal expansion between the exterior cover 2 and the flow path component 3 causes a difference in dimension in the vertical direction, distortion is suppressed as follows: That is, the liquid supply unit 3b moves relative to the head unit 3a in the direction widening the gap between them, and the vertical dimension of the flow path component 3 matches the dimension of the exterior cover 2. This suppresses distortion in the exterior cover 2 and the flow path component 3.

In addition, in the above description, the flow path component 3 is joined around the opening of the exterior cover 2 for the purpose of preventing the intrusion of droplets, dust, etc. into the exterior cover through the openings 21a and 21b, but this is not limited to this. For example, the flow path component 3 may be joined to the exterior cover 2 to prevent rattling of the flow path component 3 inside the exterior cover or for the purpose of positioning. If the flow path component 3 is joined to the exterior cover 2 for purposes other than preventing the intrusion of droplets, dust, etc. into the exterior cover through the openings 21a and 21b, the joining point between the flow path component 3 and the exterior cover 2 does not have to be around the opening 21a.

FIG. 8 is a schematic cross-sectional view showing a first modified example of the flow path part 3. As shown in FIG.
8, the flow path part of this modification has guide portions 36 that guide the movement of the liquid supply portion 3b relative to the head portion 3a. The guide portions 36 make the head portion 3a longer in the left-right direction in the figure than the liquid supply portion 3b, and extend upward from both left-right ends of the head portion 3a so as to face the side surfaces of the liquid supply portion 3b. As a result, the liquid supply portion 3b moves up and down relative to the head portion 3a while the side surfaces of the liquid supply portion 3b are guided by the guide portions 36.

The connecting portion 10 is sealed with an elastically deformable O-ring 33, so to ensure the connecting portion 10 is sealed against liquids, it is best to minimize the axial misalignment between the central axis of the connecting insertion portion 35 and the central axis of the connecting recess 34.

Providing the guide portion 36 as in Variation 1 prevents the liquid supply portion 3b from shifting left and right in the figure relative to the head portion 3a when the liquid supply portion 3b moves up and down relative to the head portion 3a. This prevents axial misalignment between the central axis of the connecting insertion portion 35 and the central axis of the connecting recess 34, and the O-ring 33 stabilizes the sealing performance of the connecting portion.

For example, the head unit 3a may be made longer than the liquid supply unit 3b in a direction perpendicular to the plane of the paper in FIG. 8, and a guide unit may be provided on the head unit that faces the side of the liquid supply unit 3b perpendicular to the plane of the paper. This prevents the liquid supply unit 3b from shifting relative to the head unit 3a in a direction perpendicular to the plane of the paper in FIG. 8 when the liquid supply unit 3b moves vertically relative to the head unit 3a.

In addition, while the guide portion 36 is provided on the head portion 3a in the configuration shown in Figure 8, it may also be provided on the liquid supply portion 3b. Furthermore, it is not limited to the configuration shown in Figure 8 as long as it can guide the relative vertical movement of the liquid supply portion 3b with respect to the head portion 3a. For example, a groove may be provided on the guide portion 36 of the head portion, and a guide protrusion that fits into this groove may be provided on the liquid supply portion.

FIG. 9 is a schematic cross-sectional view showing a second modification of the flow path part 3. As shown in FIG.
9, the flow path part 3 is divided into a lower liquid supply part 3b1 as a second member and an upper liquid supply part 3b2 as a third member. That is, in the second modification, the flow path part 3 is composed of three members: the head part 3a, the lower liquid supply part 3b1, and the upper liquid supply part 3b2.
The structure of the first connecting portion 10a connecting the lower liquid supply portion 3b1 and the head portion 3a, and the structure of the second connecting portion 10b connecting the lower liquid supply portion 3b1 and the upper liquid supply portion 3b2, are similar to the connecting portion 10 described above. That is, a connecting recess is provided on one side of the connecting portion, and a connecting insertion portion inserted into the connecting recess is provided on the other side. The gap between the inner peripheral surface of the connecting recess and the outer peripheral surface of the connecting insertion portion is sealed with an O-ring 33. By configuring the first connecting portion 10a in this way, the lower liquid supply portion 3b1 can be connected to the head portion 3a so as to be movable relative to the head portion 3a. Furthermore, by configuring the second connecting portion 10b in this way, the upper liquid supply portion 3b2 can be connected to the lower liquid supply portion 3b1 so as to be movable relative to the lower liquid supply portion 3b1.
In addition, in this second modification, the electrical circuit board 4 is fixed to the second cover member 2b and the lower liquid supply portion 3b1 by screws 6.

In the liquid ejection head shown in Figure 1, the electrical board 4 is fixed only to the second cover member 2b. However, because the thin electrical board 4 is fixed in only one place, the orientation of the electrical board 4 is unstable. Therefore, it is preferable to increase the number of fixing points for the electrical board 4 by fixing the electrical board 4 to the second cover member 2b and the flow path component 3 arranged adjacent to the electrical board 4. However, due to the difference in the linear expansion coefficient between the electrical board 4 and the flow path component 3, the dimensional change of the electrical board 4 due to thermal expansion in a high-temperature environment differs from the dimensional change of the flow path component 3. As a result, distortion occurs in the electrical board 4, which has weaker rigidity than the flow path component 3, which may cause problems such as poor electrical contact between the electrical board 4 and the FFC 5.

In contrast, in variant 2 shown in Figure 9, the flow path component 3 is composed of three members that can move relative to one another, and the electrical board 4 is fixed to the lower liquid supply section 3b1, which is located in the vertical center of the three members, and to the second cover member 2b. As a result, in a high-temperature environment, the lower liquid supply section 3b1 moves relative to the head section 3a and upper liquid supply section 3b2 in response to thermal expansion of the electrical board 4. This prevents distortion of the electrical board 4 and prevents problems such as poor electrical contact between the electrical board 4 and the FFC 5.

On the other hand, vertical dimensional differences between the flow path component 3 and the exterior cover 2 after thermal expansion due to differences in the linear expansion coefficients of the two components, as well as dimensional differences due to manufacturing errors, are absorbed by the head portion 3a and upper liquid supply portion 3b2 moving relative to the lower liquid supply portion 3b1. This also prevents distortion of the exterior cover 2 and flow path component 3.

The liquid ejection head of this embodiment can also suppress distortion of the exterior cover 2 and flow path components 3 when, for example, the vertical dimensions of the electrical board 4 differ from the specified dimensions due to manufacturing errors. In other words, if the vertical dimensions of the electrical board 4 differ from the specified dimensions, the lower liquid supply unit 3b1 moves relative to the head unit 3a and the upper liquid supply unit 3b2 when the electrical board 4 attached to the lower liquid supply unit 3b1 is screwed to the exterior cover 2. This makes it possible to absorb vertical dimensional errors of the electrical board 4, and suppress distortion of the electrical board 4 due to vertical dimensional errors of the electrical board 4.

As shown in Figure 10, the electrical board 4 may be fixed to the head portion 3a and the lower liquid supply portion 3b1. This prevents the electrical board 4 from being distorted due to the difference in thermal expansion between the flow path component 3 and the exterior cover 2 in the left-right direction in the figure.

When assembling the flow path component 3 to the exterior cover 2, there is a risk that the upper liquid supply section 3b2 may become detached from the lower liquid supply section 3b1, or that the head section 3a may become detached from the lower liquid supply section 3b1.

In addition, in the configurations shown in Figures 9 and 10, the electrical board 4 is attached to the lower liquid supply unit 3b1, and the vertical position of the lower liquid supply unit 3b1 is determined by the electrical board 4. This allows the gap between the head unit 3a and the lower liquid supply unit 3b1 and the gap between the head unit 3a and the upper liquid supply unit 3b2 to be approximately equal. However, as shown in Figure 11, in a configuration in which the electrical board 4 is not attached to the lower liquid supply unit 3b1, the vertical position of the lower liquid supply unit 3b1 cannot be determined. As a result, the lower liquid supply unit 3b1 may be assembled to the head unit 3a with a narrow gap between them. In this case, there is a risk that the connection between the lower liquid supply unit 3b1 and the upper liquid supply unit 3b2 may come loose when the upper liquid supply unit 3b2 is joined to the exterior cover 2 with screws 6.

For this reason, as shown in Figure 12, it is preferable to provide a first disconnection prevention portion 37 that prevents disconnection between the lower liquid supply portion 3b1 of the head portion 3a and a second disconnection prevention portion 38 that prevents disconnection between the lower liquid supply portion 3b1 and the upper liquid supply portion 3b2. The first disconnection prevention portion 37 and the second disconnection prevention portion 38 are provided on both the left and right sides of the flow path component 3 in the figure.

The first removal prevention part 37 is composed of a first removal prevention protrusion 37b extending horizontally from the lower end of the lower liquid supply part 3b1, and a first hook part 37a extending upward from the upper end of the head part 3a. The claw part at the tip of this first hook part 37a faces the first removal prevention protrusion 37b from above in the vertical direction.

The second removal prevention portion 38 is composed of a second removal prevention protrusion 38b extending horizontally from the upper end of the lower liquid supply portion 3b1, and a second hook portion 38a extending downward from the lower end of the upper liquid supply portion 3b2. The claw portion at the tip of this second hook portion 38a faces the second removal prevention protrusion 38b from below in the vertical direction.

By providing the first removal prevention portion 37, it is possible to prevent the head portion 3a from becoming detached from the lower liquid supply portion 3b1 when, for example, assembling the flow path part 3 to the exterior cover 2, thereby preventing the need for reassembly. Furthermore, by providing the second removal prevention portion 38, it is possible to prevent the upper liquid supply portion 3b2 from becoming detached from the lower liquid supply portion 3b1 when, for example, assembling the flow path part 3 to the exterior cover 2, thereby preventing the need for reassembly.

Furthermore, when the lower liquid supply unit 3b1 is assembled to the head unit 3a with a narrow gap between the head unit 3a and the lower liquid supply unit 3b1, and the upper liquid supply unit 3b2 is joined to the exterior cover 2 with the screw 6 in this assembled state, the following occurs: The upper liquid supply unit 3b2 moves upward as the screw 6 is tightened, and the claw portion at the tip of the second hook portion 38a abuts the second removal prevention protrusion 38b before the connection between the upper liquid supply unit 3b2 and the lower liquid supply unit 3b1 is released. The claw portion at the tip of the second hook portion 38a then lifts the lower liquid supply unit 3b1, and the lower liquid supply unit 3b1 moves upward together with the upper liquid supply unit 3b2. As a result, the upper liquid supply unit 3b2 can be joined to the exterior cover with the screw 6 without releasing the connection between the upper liquid supply unit 3b2 and the lower liquid supply unit 3b1.

In addition, the portion of the first hook portion 37a other than the claw portion faces the first removal prevention protrusion 37b from the outer left-right direction. This allows the first hook portion 37a to function as a guide portion that guides the vertical movement of the lower liquid supply portion 3b1 relative to the head portion 3a. This prevents axial misalignment between the central axis of the connecting recess 34 of the lower liquid supply portion 3b1 and the central axis of the connecting insertion portion 35 of the head portion 3a, and the O-ring 33 can stabilize the sealing of the connecting portion.

Similarly, the second hook portion 38a of the second removal prevention portion 38 functions as a guide portion that guides the relative vertical movement of the upper liquid supply portion 3b2 with respect to the lower liquid supply portion 3b1. This prevents axial misalignment between the central axis of the connecting recess 34 of the upper liquid supply portion 3b2 and the central axis of the connecting insertion portion 35 of the lower liquid supply portion 3b1, and the O-ring 33 stabilizes the sealing performance of the connecting portion.

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

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

This carriage 403 is equipped with a liquid ejection unit 440 that integrates a liquid ejection head 404 according to the present invention and a head tank 441. The liquid ejection head 404 of the liquid ejection unit 440 ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid ejection head 404 has a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and is mounted with the ejection direction facing downward.

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

The supply mechanism 494 is composed of a cartridge holder 451, which is a filling section for mounting the liquid cartridge 450, a tube 456, a liquid delivery unit 452 including a liquid delivery pump, and other components. The liquid cartridge 450 is detachably mounted in the cartridge holder 451. Liquid is delivered from the liquid cartridge 450 to the head tank 441 by the liquid delivery unit 452 via the tube 456.

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

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

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

Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head 404 is arranged on one side of the carriage 403 in the main scanning direction, beside the conveyor belt 412.

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

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

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

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

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

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

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

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

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

This liquid ejection unit consists of a liquid ejection head 404 and a tube 456 connected to the liquid supply section 444 of the liquid ejection head 404.

Note that reference numeral 442 in Figure 16 denotes an exterior cover 442. The liquid supply unit 444 may also include a head tank 441. Reference numeral 443 in Figure 16 denotes a connector that electrically connects to the electrical circuit board.

In this application, a "liquid ejecting device" is a device that includes a liquid ejection head or liquid ejection unit and ejects liquid by driving the liquid ejection head. Liquid ejecting devices include not only devices that can eject liquid onto objects onto which the liquid can adhere, but also devices that eject liquid into air or liquid.

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

For example, "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder to form a three-dimensional object.

Furthermore, "liquid ejecting devices" are not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, they also include devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

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

The "material to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, or textiles for clothing.

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

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

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

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

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

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

Also, there are liquid ejection units in which the liquid ejection head and carriage are integrated.

In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, integrating the liquid ejection head with the scanning movement mechanism. In other liquid ejection units, as shown in Figure 15, the liquid ejection head, carriage, and main scanning movement mechanism are integrated.

In some liquid ejection units, a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which the liquid ejection head is attached, integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

Also, as shown in Figure 16, there is a liquid ejection unit in which a tube is connected to the liquid ejection head, integrating the liquid ejection head with a supply mechanism.

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

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

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

The above description is merely an example, and each of the following aspects provides unique effects.
(Aspect 1)
The liquid supply device includes an internal component such as a flow path component 3, and an external component such as an external cover 2 that covers the internal component. The internal component is joined to one side such as a bottom surface and the other side such as a ceiling surface that face each other via the internal component of the external component. The internal component includes a first member such as a head portion 3a, and a second member such as a liquid supply portion 3b that is connected to the first member so as to be movable relative to the first member in a direction perpendicular to the joining surface of the internal component joined to the external component.
Generally, the exterior part is box-shaped, and has an opening on its bottom surface through which a nozzle for ejecting liquid from the liquid ejection head is exposed, and an opening on its top surface through which a supply port to which a tube for supplying liquid from an external tank is connected passes. Conventionally, the nozzle side of the interior part is bonded to the bottom surface of the exterior part with an adhesive or the like, and the top surface opposite the nozzle side is bonded to the top surface of the exterior part with an adhesive or the like to prevent liquid from entering the exterior part through these openings.
However, if the linear expansion coefficients of the internal and external components are different, there may be a difference in the dimensions of the two components after thermal expansion in a direction perpendicular to the joining surface where the internal component is joined to the external component, or there may be a difference in the dimensions of the two components in a direction perpendicular to the joining surface due to manufacturing errors. Such a difference in the dimensions of the two components in a direction perpendicular to the joining surface generates stress at the joining point in a direction perpendicular to the joining surface, and this stress may cause distortion in at least one of the external and internal components.
In contrast, in this embodiment, the second member of the internal component is configured to be movable relative to the first member of the internal component in a direction perpendicular to the joining surface. This allows the second member to move relative to the first member, even if a dimensional difference occurs between the internal component and the exterior component in the direction perpendicular to the joining surface, so that the dimension of the internal component in the direction perpendicular to the joining surface can match the dimension of the exterior component in the direction perpendicular to the joining surface. This makes it possible to prevent distortion in the exterior component and the interior component.

(Aspect 2)
In the first embodiment, the second member such as the liquid supply portion 3b is connected to the first member such as the head portion 3a with a gap therebetween in the direction perpendicular to the joining surface.
According to this, as described in the embodiment, when the dimension between the joining surfaces of an internal part such as the flow path part 3 is longer than the dimension between the joined surfaces of an external part such as the exterior cover 2, or when the linear expansion coefficient of the internal part is larger than the linear expansion coefficient of the exterior cover, the second member moves relative to the first member to narrow the gap and absorb the dimensional difference, thereby making it possible to suppress distortion of the external part and the internal part.

(Aspect 3)
In the first or second aspect, the coefficient of linear expansion of the exterior component such as the exterior cover 2 and the coefficient of linear expansion of the internal component such as the flow path component 3 are different from each other.
As described in the embodiment, the difference in linear expansion coefficient between the exterior component such as the exterior cover 2 and the internal component such as the flow path component 3 causes a difference in thermal expansion between the exterior component and the internal component, but the second member moves relative to the first member to absorb this difference in thermal expansion, thereby preventing distortion of the exterior component and the internal component.

(Aspect 4)
In any of aspects 1 to 3, a second internal component such as an electrical board 4 is provided which is fixed to a second member such as a lower liquid supply portion 3b1 and a member different from the second member such as an outer cover 2, and the internal component has a third member such as an upper liquid supply portion 3b2 which is movable relative to the second member in a direction perpendicular to the joining surface.
As described in Modification 2, this allows the second member, such as the lower liquid supply unit 3b1, to move relative to the first member, such as the head unit 3a, and the third member, such as the upper liquid supply unit 3b2, in accordance with dimensional variations in the direction perpendicular to the joining surface due to thermal expansion of the second internal component, such as the electrical board 4, and dimensional errors in the direction perpendicular to the joining surface due to manufacturing errors. This makes it possible to prevent distortion of the second internal component. Furthermore, dimensional differences in the direction perpendicular to the joining surface between an exterior component, such as the exterior cover, and an interior component, such as the flow path component 3, can be absorbed by moving the third member and the first member relative to the second member, thereby preventing distortion of the exterior component and the interior component.
Furthermore, by fixing the second internal component to a plurality of members, the position of the second internal component within the exterior component can be stabilized.

(Aspect 5)
In any of aspects 1 to 3, the internal component such as the flow path component 3 has a third member such as the upper liquid supply portion 3b2 that is movable relative to a second member such as the lower liquid supply portion 3b1 in a direction perpendicular to the joining surface, and has a first removal prevention portion 37 that prevents removal of the second member from a first member such as the head portion 3a, and a second removal prevention portion 38 that prevents removal of the second member from a third member.
As a result, as explained using Figures 11 and 12, when assembling the flow path parts to the exterior cover, it is possible to prevent the first member such as the head portion 3a from coming off the second member such as the lower liquid supply portion 3b1, and the third member such as the upper liquid supply portion 3b2 from coming off the second member.

(Aspect 6)
In the fourth or fifth aspect, the third member such as the upper liquid supply part 3b2 is connected to the second member with a gap in the direction perpendicular to the joining surface.
This allows the second member, such as the lower liquid supply unit 3b1, to move in a direction perpendicular to the joining surface independently of the first member, such as the head unit 3a, and the third member, such as the upper liquid supply unit 3b2, as described in Modification 2. This allows the second member to move in accordance with the thermal expansion and dimensional errors of the second internal component, such as the electrical board 4.

(Aspect 7)
In any of aspects 1 to 6, the internal component is a flow path component 3 for flowing a liquid such as ink, and the liquid flows from one component to another via a connection point between components constituting the internal component, such as a connecting portion 10, and a sealing member such as an O-ring 33 for sealing the liquid is provided at the connection point.
This can prevent liquid such as ink from leaking from connecting portions such as connecting parts.

(Aspect 8)
In the seventh aspect, a guide portion 36 is provided to guide the relative movement between members constituting the internal parts such as the flow path part 3 .
As a result, as described in variant example 1, it is possible to suppress positional deviation in a direction perpendicular to the relative movement direction between the members that make up the internal components, and it is possible to maintain the sealing properties of sealing members such as the O-ring 33.

(Aspect 9)
In any one of the first to eighth embodiments, a sealing material such as the seal member 8 is provided at the joint between the internal part such as the flow path part 3 and the external part such as the external cover 2 .
As a result, as described with reference to FIG. 7 , it is possible to completely seal the gap at the joint between an internal component such as the flow path component 3 and an external component such as the exterior cover 2, thereby preventing liquids and the like from entering the external component through the joint.

(Aspect 10)
The liquid ejection unit includes the liquid ejection head according to any one of Aspects 1 to 9. This can suppress distortion of the liquid ejection head, and can suppress problems such as the liquid landing position being shifted from a specified position.

(Aspect 11)
An apparatus for ejecting liquid, such as an inkjet recording apparatus serving as an image forming apparatus, includes the liquid ejection head of any one of aspects 1 to 9 or the liquid ejection unit of aspect 10.
This allows the liquid to be ejected satisfactorily.

DESCRIPTION OF SYMBOLS 1: Liquid ejection head 2: Outer cover 2a: First cover member 2b: Second cover member 3: Flow path component 3a: Head portion 3b: Liquid supply portion 3b1: Lower liquid supply portion 3b2: Upper liquid supply portion 4: Electrical circuit board 6: Screw 7: Adhesive 8: Sealing member 10: Connecting portion 10a: First connecting portion 10b: Second connecting portion 21a: Opening 21b: Opening 21c: Opening 31: Nozzle surface 31a: Nozzle 32: Supply port 33: O-ring 34: Connecting recess 35: Connecting insertion portion 36: Guide portion 37: First removal prevention portion 37a: First hook portion 37b: First removal prevention protrusion 38: Second removal prevention portion 38a: Second hook portion 38b: Second removal prevention protrusion 401: Guide member 403: Carriage 404: Liquid ejection head 405 : Main scanning motor 420 : Maintenance and recovery mechanism 440 : Liquid ejection unit 441 : Head tank 442 : Outer cover 444 : Liquid supply section 450 : Liquid cartridge 451 : Cartridge holder 452 : Liquid sending unit 456 : Tube 491A : Side plate 491B : Side plate 491C : Back plate 493 : Main scanning movement mechanism 494 : Supply mechanism

Japanese Patent Application Laid-Open No. 2021-146573

Claims (10)

Internal parts and
an exterior part that covers the internal part,
the internal component is joined to one surface and the other surface of the exterior component that face each other with the internal component interposed therebetween,
the internal component includes a first member and a second member connected to the first member so as to be movable relative to the first member in a direction perpendicular to a joining surface of the internal component joined to the exterior component ,
a second internal component secured to the second member and to a member different from the second member;
The liquid ejection head according to claim 1, wherein the internal component includes a third member connected to the second member so as to be movable relative to the second member in a direction perpendicular to the joining surface . Internal parts and
an exterior part that covers the internal part,
the internal component is joined to one surface and the other surface of the exterior component that face each other with the internal component interposed therebetween,
the internal component includes a first member and a second member connected to the first member so as to be movable relative to the first member in a direction perpendicular to a joining surface of the internal component joined to the exterior component,
the internal component has a third member connected to the second member so as to be movable relative to the second member in a direction perpendicular to the joining surface;
A liquid ejection head characterized by having a first anti-detachment portion that prevents the second member from coming off the first member, and a second anti-detachment portion that prevents the second member from coming off the third member. 3. The liquid ejection head according to claim 1 ,
The liquid ejection head is characterized in that the third member is connected to the second member with a gap therebetween in a direction perpendicular to the joining surface . 4. The liquid ejection head according to claim 1,
The liquid ejection head is characterized in that the second member is connected to the first member with a gap therebetween in a direction perpendicular to the joining surface. 5. The liquid ejection head according to claim 1,
A liquid ejection head, wherein the exterior component and the interior component have different linear expansion coefficients . 6. The liquid ejection head according to claim 1,
The internal component is a flow path component for flowing a liquid,
A liquid flows from one member to another member through a connection between the members constituting the internal component,
A liquid ejection head characterized in that a seal member for sealing the liquid is provided at the connecting portion. 7. The liquid ejection head according to claim 6 ,
A liquid ejection head comprising a guide portion for guiding relative movement between members constituting the internal components. 8. The liquid ejection head according to claim 1,
A liquid ejection head characterized in that a sealant is provided at a joint between the internal part and the external part. A liquid ejection unit comprising the liquid ejection head according to claim 1 . 10. A liquid ejection device comprising: a liquid ejection head according to claim 1 ; or a liquid ejection unit according to claim 9 .