JP7618463B2 - Liquid ejection head and liquid ejection device - Google Patents

Description

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

The inkjet recording head (liquid ejection head) mounted on an inkjet recording device as a liquid ejection device is a device that ejects ink (liquid) from fine ejection orifices, causing the ink to land on a recording medium, forming a recorded image such as characters, diagrams, and pictures. The ink ejected from the ejection orifices of the liquid ejection head travels in a generally straight line toward the recording medium, landing at the intended position and participating in the formation of the recorded image.

However, sometimes the ejected ink turns into a mist of tiny droplets that float in the atmosphere and, after drifting, adhere to the area around the ejection opening of the liquid ejection head instead of landing on the recording medium.

In this way, ink that adheres to the area around the ejection orifices may interfere with the ejection of new ink that is subsequently ejected. This is because if ink adheres to the area around the ejection orifices, when new ink is ejected, it may come into contact with the adhering ink and lose its straightness, causing the newly ejected ink to head toward the recording medium in a distorted state. As a result, the ink may not land in the intended position on the recording medium, which may impair the quality of the recorded image that is formed.

In order to remove ink adhering around the nozzles, many inkjet recording devices are equipped with a cleaning device that wipes the nozzle face of the recording head with a wiping member (wiper) made of an elastic material such as rubber to remove any adhering matter. In this case, in order to cover the entire nozzle face, i.e., from one end to the other, the wiping is performed by a path in which the wiper enters from outside one end of the nozzle face, wipes the nozzle face, and then exits to the outside of the other end of the nozzle face.

In this way, the ink adhering to the area around the ejection ports is removed from the ejection port face by the wiper, but at the same time, another problem can occur at the edge of the ejection port face. The wiper can be damaged when it comes into contact with the edge of the ejection port face. The edge of the ejection port face has a corner formed on the ridge that is the boundary between the ejection port face and the side wall surface. When the wiper enters the ejection port face from the outside of the edge, if it comes into contact with this corner forcefully, the wiper may be scratched or scraped, or the head may be damaged.

In particular, if there is a large space outside the edge of the ejection port face, the wiper may jump through the space when entering the ejection port face and hit the corner of the edge of the ejection port face directly, which may cause damage to the wiper.

In response to these issues, Patent Document 1 uses a method to reduce damage caused by contact between the wiper and the corners of the end of the ejection port surface. Specifically, by providing a wiper support part on the outside of the end of the ejection port surface, the space between the end of the ejection port surface and the wiper support part is reduced, shortening the jump distance of the wiper and reducing the impact when it hits the corners.

It is also possible to provide a damming member on the outside of the end of the discharge port surface to block the sealant, and place the sealant in the space between the outside of the end of the discharge port surface and the damming member to fill the space. In this configuration, when the wiper enters the discharge port surface, it also comes into contact with the top surface of the sealant placed on the outside of the end of the discharge port surface. In other words, by wiping the top surface of the sealant that fills the space and then continuously entering the discharge port surface, the wiper can perform a smooth wiping operation without jumping in the gap, and damage to the wiper can be reduced.

JP 2019-181879 A

However, when wiping, the wiper scrapes off the sealant that fills the space, carries it to the discharge port face, and deposits it around the discharge port, which may cause irregular discharge. In particular, if the sealant is placed on the surface of the damming member, there is a high possibility that the sealant will be scraped off by the wiper.

Therefore, the present invention aims to reduce the risk of sealant being placed on the surface of the damming member.

A liquid ejection head of the present invention includes a substrate for a liquid ejection head, the substrate having an ejection port surface from which liquid is ejected and a first side surface along a direction intersecting the ejection port surface, a blocking member including a second side surface opposed to the first side surface and a surface adjacent to the second side surface, the surface being provided along the ejection port surface and at a position protruding from the ejection port surface in a direction perpendicular to the ejection port surface, and a sealant for sealing between the first side surface and the second side surface, and the liquid ejection head is provided in a liquid ejection device having a wiper for wiping the ejection port surface , the blocking member including: The surface of the material is provided with a groove extending from the end on the side of the second side surface in a direction away from the second side surface and in a direction along or at an acute angle to the direction of relative movement between the outlet surface and the wiper when the wiper wipes the outlet surface, and in a direction perpendicular to the outlet surface , a bottom surface of the groove is at the same position as the outlet surface or at a position protruding further than the outlet surface, at least a portion of the bottom surface of the groove is exposed on the surface side, and the maximum width of the groove is 0.2 mm or more and 5 mm or less .

The present invention reduces the risk of sealant being placed on the upper surface of the sealant blocking portion.

FIG. 1 is a perspective view of an inkjet recording head; An exploded perspective view of a liquid ejection head Side view of the recording element substrate FIG. 3 is a perspective view of a recording element substrate; FIG. 1 is a partial cross-sectional perspective view of a recording element substrate; Cross-sectional view of an inkjet recording head FIG. 1 is a diagram for explaining wiping performed on an inkjet recording head; FIG. 1 shows a comparative example FIG. 1 shows a comparative example FIG. 1 shows a modified example FIG. 1 shows a modified example FIG. 1 shows a modified example FIG. 1 shows a modified example

The following describes how to implement the present invention.

Figure 1 is a schematic perspective view of an inkjet recording head 1 as a liquid ejection head according to this embodiment, and Figure 2 is an exploded perspective view showing the process of assembling the inkjet recording head 1.

The liquid ejection head 1 includes a support member 2, a recording element substrate 3 as a substrate for the liquid ejection head, an electrical connection substrate 4, an electrical connection sealant 5, a blocking member 6, and a surrounding sealant 7.

First, the support member 2 will be described (Fig. 2(a)). In the liquid ejection head 1, the support member 2 is a component that serves as a base when the recording element substrate 3, the electrical connection substrate 4, and the damming member 6 are joined with adhesive 17 (Fig. 6(a)). The support member 2 also has a flow path 18 (Fig. 6(a)) through which ink flows, and ink is supplied to the recording element substrate 3 from an ink storage component (not shown) via the flow path 18 of the support member 2.

The support member 2 is required to have strength and a flat bonding surface as a base for the inkjet recording head 1, and may be made of resin, metal, ceramic, or the like from the viewpoint of ease of processing the internal flow path 18. In this embodiment, a plate made of alumina (aluminum oxide, Al ₂ O ₃ ) is used as the support member 2.

Next, the recording element substrate 3 will be described. Fig. 3 is a side view of the recording element substrate 3, Fig. 4 is a perspective view of the recording element substrate 3, and Fig. 5 is a partial cross-sectional perspective view of the recording element substrate 3.

In this embodiment, the recording element substrate 3 includes a silicon substrate 8 having a thickness of 0.6 to 0.8 mm and a resin discharge port forming member 9 having a thickness of 0.01 to 0.1 mm in which the discharge ports 14a are formed, and is configured by bonding the two members together. By bonding the silicon substrate 8 and the resin discharge port forming member 9 together, the recording element substrate 3 has six surfaces. That is, the discharge port surface 10 in which the discharge ports 14a are formed, its back surface 11, and four side surfaces 12 adjacent to the discharge port surface 10 via ridges. The side surfaces 12 are aligned in a direction intersecting the discharge port surface 10. With regard to the side surfaces 12, the side surfaces along the longitudinal direction of the recording element substrate 3 are referred to as side surfaces 12a (first side surfaces), and the side surfaces along the lateral direction are also referred to as side surfaces 12b (second side surfaces). Some of the side surfaces are hidden in FIG. 4.

The silicon substrate 8 of the recording element substrate 3 is provided with a plurality of electrothermal conversion element groups 13 as energy generating elements that generate energy for ejecting liquid, and an electrical connection terminal group 16 for electrical connection to the outside. The electrothermal conversion element group 13, the electrical connection terminal group 16, and the electrical wiring (not shown) connecting them are formed on the silicon substrate 8 by film formation technology. The electrical connection terminal group 16 is electrically connected to electrical connection components to receive drive signals and drive power from the outside.

As shown in FIG. 2(a), in this embodiment, an electrical connection board 4 (flexible electrical wiring board) is used, and the electrical connection terminal group 16 and the electrical connection board 4 are connected by wire bonding. Furthermore, in order to insulate and protect the wire bonding and its surrounding area, it is covered with an epoxy-based electrical connection sealant 5.

The end of the electrical connection board 4 opposite the end connected to the electrical connection terminal group 16 of the recording element board 3 is connected to a board (not shown) for controlling the drive signal and drive power for driving the liquid ejection head 1.

A group of ejection ports 14a (hereinafter also referred to as ejection port group 14) corresponding to the electrothermal conversion elements 13 is formed on the ejection port surface 10 of the recording element substrate 3 by photolithography. An ink supply port 15 is provided on the back surface 11 of the recording element substrate 3, and by communicating with the opening of the flow path 18 of the support member 2 described above, a flow path structure is formed for supplying ink to the ejection port group 14.

In this embodiment, the ink ejection port groups 14 are arranged as two rows of ejection port groups, and the ink supply port 15 has one flow path structure, but the number of rows of the ejection port groups 14 and the number of flow path structures can be appropriately adjusted according to the number of ink colors installed in the inkjet recording device.

Next, the damming member 6 for damming the peripheral sealant 7 will be described. The damming member 6 has an opening 19 that is larger than the outer shape of the recording element substrate 3 and is used to house the recording element substrate 3 inside. The recording element substrate 3 and the damming member 6 are bonded to the support member 2 so that the recording element substrate 3 is contained within this opening 19, and the damming member 6 is configured as a bank that surrounds the outer periphery of the recording element substrate 3 (FIG. 2(b)).

Figure 6(a) shows the cross section B-B in Figure 2(b).

By joining the recording element substrate 3 and the damming member 6 to the support member 2, a space 20 (gap) is formed between the side surface 12 of the recording element substrate 3, the opposing side surface 24 (second side surface) of the damming member 6, and the support member 2.

The top surface 22 (surface) of the damming member 6 that runs along the ejection port surface 10 is disposed at a position that protrudes from the ejection port surface 10 of the recording element substrate 3 in a direction perpendicular to the ejection port surface 10. A groove 21 is formed on the top surface 22 of the damming member 6 from the end on the side of the side surface 24 that constitutes the opening 19. A detailed explanation of the groove 21 will be given together with the explanation of wiping, which will be described later.

The damming member 6 can be formed by cutting metal or ceramic, or by resin molding using a mold. In this embodiment, a damming member 6 formed by resin molding is used. The damming member 6 may be molded integrally with the support member 2.

The space 20 created around the outer periphery of the recording element substrate 3 by placing the damming member 6 is filled with a peripheral sealant 7 as shown in FIG. 1. There are no particular restrictions on the peripheral sealant 7 that can be used, but it is convenient to apply a urethane-based liquid sealant that hardens at room temperature.

Figure 6(b) is a cross section taken along line A-A in Figure 1, showing the state after the peripheral sealant 7 has been placed. By filling the space 20 with the peripheral sealant 7, the side surface 12 of the recording element substrate 3 can be covered. Note that the appropriate amount of peripheral sealant 7 to be filled is one that does not overflow onto the ejection port surface 10 of the recording element substrate 3 when the peripheral sealant 7 is applied.

At this time, the peripheral sealant 7 may creep up to the groove 21 of the damming member 6 due to surface tension, but it does not creep up to the top surface 22 of the damming member 6, which is located higher than the bottom surface 21a of the groove 21. After that, the peripheral sealant 7 hardens, and the liquid ejection head 1 is completed.

The liquid ejection head 1 completed in this way is mounted on the inkjet recording device body, and when it receives a drive signal and drive power from the inkjet recording device body via the electrical connection parts, the liquid ejection head 1 can eject ink.

When ink is repeatedly ejected, ink floating in the atmosphere may gradually adhere to the ejection port surface 10 as unwanted ink. For this reason, in an inkjet recording device 1000 (Figure 7) having a liquid ejection head 1 and a wiper 23, wiping is performed by the wiper 23 to wipe the ejection port surface 10.

Next, we will explain this wiping. Wiping is an operation in which a rubber blade-shaped wiper 23 with a thickness of about 1 mm is placed in contact with the ejection port surface 10 on which ink is adhering, and the wiper is scanned in one direction to wipe off the ink and clean the ejection port surface 10.

Figure 7(a) is a plan view showing wiping the liquid ejection head 1. In order to wipe the entire ejection port surface 10 on which ink is attached in one wiping, it is desirable to make the width of the wiper 23 larger than the width of the recording element substrate 3. Here, in this embodiment, the width refers to the length in the direction along the longitudinal direction of the liquid ejection head 1.

In addition, wiping can be started from the top surface 22 on one side of the blocking member 6 located outside the ejection port surface 10, and scanned in the direction of arrow Y to the top surface 22 of the blocking member 6 on the opposite side, thereby wiping the entire surface of the ejection port surface 10 from end to end.

Figure 7(b) is a cross-sectional view taken along line C-C in Figure 7(a), and Figure 7(c) is a partially enlarged view of region D in Figure 7(b). First, the wiper 23 comes into contact with the top surface 22 of the damming member 6 arranged on the outside of the recording element substrate 3, then passes over the surface of the peripheral sealant 7 and enters the ejection port surface 10. It then wipes the ejection port surface 10, and is scanned again over the surface of the peripheral sealant 7 on the opposite side, and over the top surface 22 of the peripheral seal damming member 6.

Here, the damming member 6 is provided with a groove 21 dug lower than the top surface 22, so that the sealant 7a that rises to the bottom surface 21a of the groove 21 due to surface tension when the peripheral sealant 7 is applied remains inside the groove 21 and hardens. In this state, even when wiping is performed, the wiper 23 passes over the top surface 22, so the sealant 7a that has risen to the bottom surface 21a of the groove 21 is less likely to come into direct contact with the wiper 23, reducing the risk of the sealant 7 being scraped off by the wiper 23.

There are no particular limitations on the shape of the groove 21, but by making the depth of the groove 21 at least 0.2 mm deeper than the top surface 22, the sealant 7a that has climbed up onto the bottom surface 21a of the groove 21 can be prevented from climbing up further onto the top surface 22. On the other hand, if the groove 21 is made too deep, there is a risk that it will be buried together with the surrounding sealant 7 when filling the space 20. For this reason, it is preferable that the bottom surface 21a of the groove 21 is at the same position as the ejection port surface 10 in the direction perpendicular to the ejection port surface 10 or at a position protruding from the ejection port surface 10. More preferably, the depth is such that the position of the bottom surface 21a is at a height position approximately equal to that of the ejection port surface 10.

There is no particular limit to the width of the groove 21, but by making it about 0.2 mm or more, it becomes easier to fully contain the sealant 7a that has run up. On the other hand, if the width is too wide, there is a possibility that the wiper will enter the groove 21 when it is bent, so it is preferable to make it about 5 mm or less. In other words, it is preferable that the maximum width of the groove 21 is 0.2 mm or more and 5 mm or less. In addition, the cross section of the groove 21 is not limited to a rectangle, and it is also acceptable for it to be semicircular or inverted triangular. In addition, by making the shape of the groove 21 narrower in the extension direction away from the space 20, it is expected that the effect of capillary force will be imparted to the groove 21, making it easier for the sealant 7 to enter the groove 21.

In this embodiment, grooves 21 with a rectangular cross section having a width of 1 mm and a depth of 0.5 mm are provided at 2 mm pitch on two side surfaces 24 (24a) of the opening 19 of the damming member 6 along the longitudinal direction of the recording element substrate 3 (X direction in FIG. 7A). The grooves 21 extend from the side surfaces 24 to a position not reaching the outer periphery of the damming member 6 along a direction intersecting the longitudinal direction (preferably the Y direction, which is a direction perpendicular to the longitudinal direction). The extension direction of the grooves 21 is along the movement direction of the wiper 23 (the relative movement direction between the wiper 23 and the discharge port surface 10). In this embodiment, the longitudinal direction of the recording element substrate 3 is along the longitudinal direction of the liquid discharge head 1. The bottom surface 21a of the groove 21, which is 0.5 mm deep, is arranged so that it is at the same height as the discharge port surface 10. The groove 21 only needs to be provided in the area where the wiper 23 passes during wiping, and in this embodiment, the wiper 23 passes over the two side surfaces 24a in the Y direction and passes through an area inside the two side surfaces 24b in the X direction. Therefore, the groove 21 is not provided on the side surface 24b (fourth side surface) of the damming member 6 that faces the side surface 12b (third side surface) of the recording element substrate 3.

In addition, the side surface 12 of the recording element substrate 3 is protected by filling it with the peripheral sealant 7, so damage caused by the wiper 23 colliding with the side surface 12 can be suppressed.

Furthermore, as shown in FIG. 7(c), it is also effective to make the corners 22b of the top surface 22 rounded in order to reduce damage when the wiper 23 wipes the discharge port surface 10 and contacts the top surface 22 of the blocking member 6 on the opposite side.

Figure 8 shows the wiping of a liquid ejection head 100 having a damming member 60 without grooves 21, which is Comparative Example 1. Because there are no grooves 21, the sealant 70 filled to fill the space has crept up to the top surface of the damming member 60. The peripheral sealant 70a that has crept up and hardened is thin and easily peeled off, so there is a risk that it will be scraped off by the wiper 230 as shown in Figure 8(b). If the scraped off peripheral sealant 70b is carried by the wiper 230 and adheres to the ejection port surface, there is a risk of ejection distortion.

Figure 9 shows the wiping of a liquid ejection head 110 that does not have a damming member 6, which is Comparative Example 2. Since there is no damming member 6 and the side surface 120 of the recording element substrate 30 cannot be protected by the surrounding sealant 7, the wiper 231 hits the side surface 120 hard and penetrates onto the ejection port surface. This creates the risk of damaging the wiper 231 and the recording element substrate 30.

In contrast to these comparative examples, as described above, in this embodiment, the groove 21 can reduce the risk of the peripheral sealant 7 being placed on the top surface of the damming member 6, and the peripheral sealant 7 can be prevented from being scraped off by the wiper 23 during wiping. In addition, since the side surface 12 of the recording element substrate 3 is protected by the peripheral sealant 7, damage to the wiper 23 and recording element substrate 3 during wiping can be reduced.

(Modification)
A modification of the present invention is shown in FIGS.

As shown in FIG. 10(a), the groove 21 can be provided on the side surface 24b of the opening 19 of the damming member 6 along the short-side direction (Y direction) of the recording element substrate 3. That is, the groove 21 can be provided around the entire circumference of the opening 19 of the damming member 6. If the groove 21 is provided in a direction perpendicular to the wiping direction (Y direction) as shown in FIG. 10(a), the wiper 23 may get caught in the groove 21. Therefore, it is more preferable to arrange the groove 21 so that the angle that intersects with the wiping direction is an acute angle (preferably about 10° to 45°), as shown in FIG. 10(b) and FIG. 10(c). This reduces the risk of the wiper 23 getting caught in the groove.

Also, as shown in FIG. 11(a), the groove 21 can be arranged so as to extend from the opening 19 to the outer periphery of the damming member 6. That is, the groove 21 can reach from the side surface 24 of the damming member 6 to the surface 26 on the opposite side of the side surface 24. This allows a large amount of sealant 7 to be accommodated in the groove 21, and the sealant 7 can be prevented from running up onto the top surface 22 of the damming member 6. Note that a sealing member may be used to cover the liquid ejection head 1 from the ejection port surface 10 side in order to prevent the ejection port surface 10 from drying. As shown in FIG. 11(b), if there is a surface area 25 on the outer periphery of the groove 21 on the top surface 22 of the damming member 6 where the sealing member can abut, this area 25 can be used as a sealing area when the sealing member is used to cover the ejection port surface 10. Therefore, such a form is preferable from the viewpoint of preventing the ejection port surface 10 from drying.

Figure 12 shows an example in which a groove 21 is provided near the corner 19a between the side 24a and side 24b of the opening 19. When filling the space 20 between the recording element substrate 3 and the damming member 6 with the peripheral sealant 7, the peripheral sealant 7 is stagnant and difficult to spread at the corner 19a of the opening 19, and more peripheral sealant 7 may be applied than in other areas. Therefore, since there is a greater risk of the peripheral sealant 7 climbing up onto the top surface 22 near the corner 19a than in other areas, it is preferable to provide the groove 21 at least near the corner 19a. It is also effective to provide grooves 21 in other areas and to arrange more grooves 21 at a higher density near the corner 19a.

As shown in FIG. 13, in the liquid ejection head 1, a long line head may be formed by arranging multiple recording element substrates 3. The above-mentioned groove 21 can also be provided in such a line head. Multiple recording element substrates 3 are arranged inside the opening 19 of the damming member 6. In the case of a line head, the peripheral sealant 7 tends to stagnate near the portion between the adjacent recording element substrates 3a (substrate for the first liquid ejection head) and recording element substrate 3b (substrate for the second liquid ejection head). Therefore, it is preferable to provide the groove 21 (21b) at least near the position facing the portion between the adjacent recording element substrates 3. In addition, it is also effective to provide the grooves 21 in other areas and to arrange more grooves 21 at a higher density near the opposing positions of the portions between the recording element substrates.

1 Liquid ejection head 3 Recording element substrate (substrate for liquid ejection head)
6 damming member 7 peripheral sealant 9 ejection port forming member 10 ejection port surface 12 side surface of recording element substrate 21 groove 22 surface of damming member 24 side surface of damming member

Claims (14)

a liquid ejection head substrate including an ejection port surface for ejecting liquid and a first side surface extending in a direction intersecting the ejection port surface;
a damming member including: a second side surface opposed to the first side surface; and a surface adjacent to the second side surface, the surface being provided along the discharge port surface and at a position protruding beyond the discharge port surface in a direction perpendicular to the discharge port surface;
a sealant for sealing between the first side surface and the second side surface;
a liquid ejection head provided in a liquid ejection device having a wiper for wiping the ejection port surface ,
a groove is provided on the surface of the damming member, the groove extending from an end portion on the second side surface side in a direction away from the second side surface and in a direction along or at an acute angle with a direction of relative movement between the discharge port surface and the wiper when the wiper wipes the discharge port surface ,
A liquid ejection head characterized in that, in a direction perpendicular to the ejection port surface, a bottom surface of the groove is at the same position as the ejection port surface or at a position protruding further than the ejection port surface, at least a portion of the bottom surface of the groove is exposed on the surface side, and a maximum width of the groove is 0.2 mm or more and 5 mm or less . The liquid ejection head according to claim 1, wherein the sealant is disposed so as to cover at least a portion of the bottom surface of the groove from the second side surface. The liquid ejection head according to claim 1 or 2, wherein a plurality of the grooves are provided. the second side surface is aligned along a longitudinal direction of the liquid ejection head,
The liquid ejection head according to claim 1 , wherein the groove extends in a direction intersecting the longitudinal direction. the damming member includes a fourth side surface adjacent to the front surface and the second side surface, facing a third side surface different from the first side surface of the liquid ejection head substrate, the fourth side surface being aligned along a direction intersecting the longitudinal direction;
The liquid ejection head according to claim 4 , wherein no groove is provided at an end of the front surface on the side of the fourth side surface. the damming member has a fourth side surface adjacent to the second side surface and facing a third side surface different from the first side surface of the liquid ejection head substrate,
The liquid ejection head according to claim 1 , wherein the groove is provided at least in the vicinity of a corner between the second side surface and the fourth side surface. The liquid ejection head according to any one of claims 1 to 6, wherein the groove does not reach from the second side surface to the surface of the blocking member opposite the second side surface. The liquid ejection head according to any one of claims 1 to 6, wherein the groove extends from the second side surface to a surface of the blocking member opposite the second side surface. the second side surface is aligned along a longitudinal direction of the liquid ejection head,
9. The liquid ejection head according to claim 1, wherein a maximum length of the groove along the longitudinal direction is 0.2 mm or more and 5 mm or less. The liquid ejection head according to claim 1 , wherein the groove extends in a direction parallel to the direction of relative movement between the ejection port face and the wiper when the wiper wipes the ejection port face. A liquid ejection head described in any one of claims 1 to 10, wherein the direction in which the groove extends intersects the direction of relative movement between the ejection port face and the wiper when the wiper wipes the ejection port face at an angle of 10° to 45°. 12. The liquid ejection head according to claim 1, wherein a plurality of the liquid ejection head substrates are arranged along a longitudinal direction of the liquid ejection head. A liquid ejection head according to any one of claims 1 to 12 ,
The wiper ;
A liquid ejection device comprising: The liquid ejection device according to claim 13 , wherein a plurality of the grooves are provided in an area of the ejection port face that overlaps with the wiper when the wiper wipes the ejection port face.

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