JP2024078305A - Laminate, liquid ejection head, and manufacturing method thereof and liquid ejection apparatus - Google Patents

Abstract

To provide a laminate that can suppress the ingress of an adhesive into an area that should avoid adhesion of the adhesive.SOLUTION: There is provided a laminate which includes at least one pair of plate-like members 12, 13 stacked together. The mutually-opposing surfaces of the pair of plate-like members 12, 13 are joined to each other by an adhesive 22. The laminate includes an adhesive presence area 23 in which the adhesive 22 is interspersed between the opposing surfaces of the pair of plate-like members 12, 13 and an adhesive avoidance area 24 in which the adhesive 22 is not interspersed. On the opposing surface of at least one plate-like member 12 of the pair of plate-like members, an adhesive application part 18 which is a recess or hole, and an adhesive escape part 19 which is a recess or hole that is smaller in plane shape than the adhesive application part 18 are formed. On the opposing surfaces of the pair of plate-like members 12, 13, the adhesive application part 18 is located between the adhesive escape part 19 and the adhesive avoidance area 24.SELECTED DRAWING: Figure 8

Description

The present invention relates to a laminate, a liquid ejection head, and a manufacturing method thereof and a liquid ejection device.

A liquid ejection head typically includes a laminate in which multiple plate-like members are stacked and bonded together with an adhesive. Patent Document 1 describes a configuration in which a plate constituting a flow path member, which is part of the liquid ejection head, is provided with multiple escape grooves that allow some of the adhesive applied to bond the plate to another member to flow in.

Patent No. 6616156

In recent liquid ejection heads, there is a demand for increasing resolution by arranging ejection ports at a high density to improve the quality of images formed by liquid ejection, and for arranging various functional components to increase functionality. It is desirable to avoid adhesion of adhesive to these ejection ports and functional components, as this may cause a decrease in function or malfunction. In the configuration described in Patent Document 1, the area on the plate to which adhesive is applied is not specified, and the relative positions of the area to which adhesive is applied, the area to which adhesive should not adhere, and the escape groove are not specified. Therefore, even if an escape groove is provided, there is still a possibility that adhesive will adhere to the ejection ports and functional components.

The object of the present invention is to provide a laminate and a liquid ejection head that can prevent the adhesive from entering areas where the adhesive should not be attached, as well as a manufacturing method and a liquid ejection device for the same.

The present invention is a laminate including at least one pair of plate-like members stacked on top of each other, the opposing surfaces of the pair of plate-like members being bonded to each other with an adhesive, the opposing surfaces of the pair of plate-like members having an adhesive-presenting region where an adhesive is present between the opposing surfaces of the pair of plate-like members, and an adhesive-avoiding region where no adhesive is present, the opposing surfaces of at least one of the pair of plate-like members having an adhesive-applied portion which is a recess or hole, and an adhesive-releasing portion which is a recess or hole having a smaller planar shape than the adhesive-applied portion, the adhesive-applied portion being located between the adhesive-releasing portion and the adhesive-avoiding region on the opposing surfaces of the pair of plate-like members.

The present invention makes it possible to prevent the adhesive from entering areas where it should not be adhered.

1 is a perspective view of a main part of a liquid ejection device according to a first embodiment of the present invention; FIG. 2 is a perspective view of a liquid ejection head of the liquid ejection device shown in FIG. 1 . 3A and 3B are a plan view and a cross-sectional view of the liquid ejection head shown in FIG. 2. 11A to 11C are plan views showing a process of joining an ejection port forming member and a cover plate of a liquid ejection head of a comparative example. FIG. 4 is an exploded perspective view of a portion of the laminate of the liquid ejection head shown in FIGS. 4A and 4B are enlarged cross-sectional and plan views of essential parts illustrating a bonding process of a discharge port forming member and a cover plate of the liquid discharge head shown in FIGS. 7A and 7B are enlarged cross-sectional and plan views of a main part, illustrating a step subsequent to the step illustrated in FIG. 6; 8A and 8B are enlarged cross-sectional and plan views of a main part, illustrating a step subsequent to the step illustrated in FIG. 7; FIG. 4 is an enlarged plan view of a portion of the liquid ejection head according to a modified example of the first embodiment of the present invention. 5A and 5B are a plan view and an enlarged plan view of a portion of a liquid ejection head according to a second embodiment of the present invention; FIG. 11 is a plan view of a liquid ejection head according to a third embodiment of the present invention. FIG. 13 is a plan view of a liquid ejection head according to a fourth embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First Embodiment
The configurations of a laminate, a liquid ejection head, and a liquid ejection device according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a perspective view of the main parts of the liquid ejection device of this embodiment. Figure 2 is a perspective view of a liquid ejection head 1 of the liquid ejection device shown in Figure 1. Figure 3(A) is a plan view of the liquid ejection head 1 shown in Figure 2, and Figure 3(B) is a cross-sectional view taken along line B-B of Figure 3(A).

(Configuration of Liquid Ejection Apparatus)
The liquid ejection device of this embodiment shown in Fig. 1 is a one-pass type inkjet recording device that ejects droplets from a liquid ejection head 1 onto a recording medium 2 to form images, characters, patterns, etc. The liquid ejection device has a transport mechanism including rollers 3 and the like, which transports the recording medium 2 so that the recording medium 2 passes through a position facing the ejection ports 4 (see Figs. 2 and 3) of the liquid ejection head 1. The liquid ejection head 1 shown in Fig. 2 is a full-line type head in which the ejection ports 4 are arranged across an area corresponding to the full width of the recording medium 2. The ejection of droplets from the ejection ports 4 of the liquid ejection head 1 and the transport of the recording medium 2 in the direction of arrow A by the transport mechanism are alternately repeated to perform recording on the entire surface of the recording medium 2.

(Configuration of Liquid Ejection Head)
The liquid ejection head 1 shown in Fig. 2 has a configuration in which a plurality of element substrates 5 are attached to a long, thin housing 6. Liquid ink is supplied to each element substrate 5 from a liquid container (ink tank) (not shown) through a liquid flow path in the housing 6. In a liquid ejection device that performs color recording, paths including liquid containers and liquid flow paths for each color are respectively configured, and liquid ink of each color is supplied to the element substrate 5 through independent paths. An electric wiring substrate 7 that supplies power and signals required for liquid ejection is attached to the housing 6, and the electric wiring substrate 7 is connected to each element substrate 5 by a flexible connection substrate 8.

(Basic configuration of element substrate)
As shown in FIG. 3, each element substrate 5 is a laminated body having a multi-layer structure in which a connection member 9, a substrate 10, a flow path forming member 11, a discharge port forming member 12, and a cover plate 13 are laminated in this order. The substrate 10 is provided with a common flow path 14 and an individual flow path 15 constituting a supply path, and the common flow path 14 is connected to the liquid flow path (not shown) in the housing 6 described above through a connection opening 16 of the connection member 9. The flow path forming member 11 is provided with a pressure chamber 17, which is connected to the individual flow path 15 of the substrate 10. The discharge port forming member 12 is provided with a discharge port 4 that opens toward the outside, which is connected to the pressure chamber 17 of the flow path forming member 11. The discharge port forming member 12 is also provided with an adhesive application portion 18 that is a groove-shaped recess or hole, and a plurality of adhesive escape portions 19 that are recesses or holes. The adhesive application portion 18 and the plurality of adhesive escape portions 19 will be described later. A plurality of pressure chambers 17 and ejection ports 4 are provided, and the ejection ports 4 are arranged in a row to form an ejection port row 4A. The common flow paths 14 of the substrate 10 are provided at positions on both sides of each ejection port 4 and extend along the ejection port row 4A. The cover plate 13 is provided with openings 20 extending along the ejection port row 4A so as not to block each ejection port 4. The ejection ports 4 are exposed to the outside through the openings 20. Therefore, the liquid container and liquid flow path of the housing 6 (not shown) communicate with the pressure chamber 17 through the connection opening 16, the common flow path 14, and the individual flow paths 15, and the ejection ports 4 connected to the pressure chambers 17 open toward the outside of the liquid ejection head 1. Energy generating elements 21 (e.g., heating elements or piezoelectric elements) are formed by semiconductor processing at positions facing each ejection port 4 on the flow path forming member 11 side of the substrate 10. In addition, although not shown, the substrate 10 is provided with electrical circuits and electrical wiring electrically connected to the energy generating elements 21, as well as electronic devices such as a temperature sensor, which are connected to the electrical wiring substrate 7 via a connection substrate 8.

The substrate 10 is preferably made of a semiconductor substrate or the like on which the energy generating element 21, electric circuits, electric wiring, electronic devices, etc. can be formed, and on which the flow paths 14, 15 can be formed by MEMS (Micro Electro Mechanical Systems) processing. The flow path forming member 11, the discharge port forming member 12, the connection member 9, and the cover plate 13 may be made of any material, such as a resin material, an inorganic material, a photosensitive resin material, or a semiconductor substrate. When the flow path forming member 11, the discharge port forming member 12, the connection member 9, and the cover plate 13 are made of a resin material, various recesses (pressure chamber 17, discharge port 4, connection opening 16, opening 20, adhesive application portion 18, adhesive escape portion 19, etc.) can be formed by laser processing. When the flow path forming member 11, the discharge port forming member 12, the connection member 9, and the cover plate 13 are made of an inorganic material, various recesses can be formed by dicing. When the flow path forming member 11, the discharge port forming member 12, the connection member 9, and the cover plate 13 are made of a photosensitive resin material, various recesses can be formed by photocuring. When the flow path forming member 11, the discharge port forming member 12, the connection member 9, and the cover plate 13 are semiconductor substrates, various recesses can be formed by MEMS processing.

In the liquid ejection head 1 of this embodiment, liquid is supplied to the pressure chamber 17 from the liquid container and liquid flow path of the housing 6 (not shown) through the connection opening 16, the common flow path 14, and the individual flow path 15. Then, an electric signal is supplied to the energy generating element 21 at an appropriate timing from the electric wiring board 7 and the connection board 8 through an electric circuit and an electric wiring (not shown). The energy generating element 21, which is driven by the electric signal, generates energy (for example, heat or pressure), and a part of the liquid inside the pressure chamber 17 to which the energy is supplied is ejected as droplets from the ejection port 4 to the outside. In this embodiment, as shown in FIG. 3B, two common flow paths 14 and individual flow paths 15 are connected to one pressure chamber 17. Then, a circulation flow is formed in which liquid is supplied from one common flow path 14 and individual flow path 15 to the pressure chamber 17, and the liquid is returned from the pressure chamber 17 to the individual flow path 15 and the other common flow path 14. However, two individual flow paths 15 connected to one pressure chamber 17 may be connected to one common flow path 14. In this case, the supply of liquid to the pressure chamber 17 and the recovery of liquid from the pressure chamber 17 are performed using the same common flow path 14. Also, one common flow path 14 and one individual flow path 15 may be connected to one pressure chamber 17. In this case, liquid is supplied to the pressure chamber 17, but the recovery of liquid from the pressure chamber 17 does not have to be performed.

The liquid ejection head 1 may be configured to eject liquid ink of the same color from all the ejection ports 4. Alternatively, it may be configured to eject liquid ink of different colors from one liquid ejection head 1. In that case, a path including a common flow path 14, an individual flow path 15, and a pressure chamber 17 is provided independently for each color so that the liquid ink of different colors is ejected from different ejection port rows 4A. When ejecting liquid ink of different colors from one liquid ejection head 1, it is preferable to use liquid ink of the same color or liquid ink of different densities in order to suppress uneven density during recording. However, the liquid ejected from the liquid ejection head 1 of this embodiment may be a liquid other than ink. The liquid ejection head 1 is not limited to the above-mentioned configuration and can be arbitrarily changed, and may be a type of head that can move in a direction perpendicular to the conveying direction (arrow A direction) of the recording medium, or may be a head of another form.

(Joint between discharge port forming member and cover plate)
As shown in Fig. 3B, the liquid ejection head 1 has an element substrate 5 which is a laminate of a plurality of plate-like members. A pair of plate-like members which are laminated together and form a part of the element substrate 5, specifically, in this embodiment, a joint between the ejection port forming member 12 and the cover plate 13, employs a structure which is a main feature of the present invention. The opposing surfaces of the pair of plate-like members, the ejection port forming member 12 and the cover plate 13, which face each other, are joined to each other by an adhesive 22. However, there are an adhesive present region 23 where the adhesive 22 is interposed between the opposing surfaces 12a, 13a of the ejection port forming member 12 and the cover plate 13, and an adhesive avoidance region 24 where the adhesive 22 is not interposed. In this embodiment, the adhesive present region 23 is provided over almost the entire area of the ejection port forming member 12, and a part of the adhesive present region 23, specifically, a region including the ejection port 4, is the adhesive avoidance region 24. This is to firmly bond the discharge port forming member 12 and the cover plate 13 and prevent the adhesive 22 from adhering to the discharge port 4. In order to realize such a configuration, an adhesive applying portion 18 and a plurality of adhesive escape portions 19 are formed on the opposing surface 12a of at least one of the pair of plate-shaped members, that is, in this embodiment, the discharge port forming member 12. The adhesive applying portion 18 is a groove-shaped recess or hole. The adhesive escape portion 19 is a recess or hole having a smaller planar shape than the adhesive applying portion 18. The adhesive applying portion 18 is located between the adhesive escape portion 19 and the adhesive avoidance region 24 on the opposing surfaces 12a, 13a of the discharge port forming member 12 and the cover plate 13. This configuration has the effect of suppressing the adhesive 22 from adhering to the discharge port 4 and its surroundings, as shown in FIG. 3. This point will be described.

If the adhesive gets into the inside of the discharge port 4 in the liquid discharge head, liquid discharge from the discharge port 4 becomes impossible or unstable. Therefore, in order to prevent the adhesive 22 from entering the inside of the discharge port 4, it is desirable to suppress the adhesion of the adhesive 22 to the discharge port 4 and its vicinity. In other words, it is desirable to make the discharge port 4 and its vicinity into an adhesive avoidance area 24. In the liquid discharge head, when the cover plate 13 is bonded to the discharge port forming member 12, the adhesive 22 is applied to the discharge port forming member 12, and when the cover plate 13 is laminated and pressed on the surface on which the adhesive 22 is formed, the adhesive 22 is spread. Usually, the adhesive 22 is applied at a position away from the discharge port 4 in consideration of the spread of the adhesive 22. However, it is difficult to apply the adhesive 22 evenly. For example, in the comparative example shown in FIG. 4(A), the adhesive 22 is applied so that the central part of the discharge port forming member 12 in the longitudinal direction D1 is widened. In this state, when the cover plate 13 is pressed toward the discharge port forming member 12 to the desired position, the adhesive 22 is further spread, and as shown in FIG. 4B, the adhesive 22 in the center part in the longitudinal direction D1, which is particularly wide when applied, may reach the discharge port 4. If the adhesive 22 that has reached the discharge port 4 penetrates into the inside of the discharge port 4, liquid discharge from the discharge port 4 becomes impossible or unstable, and the function as a liquid discharge head cannot be fulfilled.

In contrast, in this embodiment, a configuration is adopted in which the adhesive 22 does not reach the ejection port 4 or its vicinity during the process of bonding the cover plate 13 to the ejection port forming member 12. This bonding process will be described with reference to Figures 5 to 8. Figure 5 is an exploded perspective view of a part of the element substrate 5, which is a laminate of the liquid ejection head 1 of this embodiment, before bonding the cover plate 13 and the ejection port forming member 12. Figures 6 to 8 sequentially show the bonding process of the cover plate 13 and the ejection port forming member 12. Figures 6 (A), 7 (A), and 8 (A) are enlarged cross-sectional views of a main part of the element substrate 5 (part C in Figure 3 (A)), and Figures 6 (B), 7 (B), and 8 (B) are enlarged plan views of a main part of the ejection port forming member 12. The ejection port forming member 12 of this embodiment has an ejection port 4, an adhesive application part 18 which is an elongated linear groove-shaped recess, and a number of adhesive escape parts 19 which are recesses with a circular planar shape. The adhesive escape portions 19 have a smaller diameter than the discharge port 4, and many of them are arranged side by side.

To construct the laminate (element substrate 5) of this embodiment, a pair of plate-like members, that is, a discharge port forming member 12 having a discharge port 4, an adhesive application portion 18, and an adhesive escape portion 19 as shown in FIG. 5, and a cover plate 13 having an opening 20 are bonded. The cover plate 13 may be formed of any material such as a resin material, an inorganic material, a photosensitive resin material, or a semiconductor substrate, but is formed of stainless steel in this embodiment. In this bonding process, as shown in FIG. 6, an adhesive 22 is applied to the adhesive application portion 18 of the discharge port forming member 12. Then, the discharge port forming member 12 and the cover plate 13 are laminated together so that the opposing surface 12a on which the adhesive application portion 18 to which the adhesive 22 is applied faces the opposing surface 13a of the cover plate 13. The adhesive 22 may be any adhesive such as an epoxy resin adhesive or a polyimide resin adhesive, but benzocyclobutene is used in this embodiment. The cover plate 13 is laminated on the surface (opposing surface 12a) of the discharge port forming member 12 opposite to the surface in contact with the flow path forming member 11. As shown in FIG. 7, by pressing the cover plate 13 in a laminated state on the discharge port forming member 12, the adhesive 22 applied to the adhesive application portion 18 is spread from the adhesive application portion 18 to the periphery. At the time when the cover plate 13 starts to be pressed against the discharge port forming member 12 in this way, the spread amount L of the adhesive 22 from the adhesive application portion 18 to the discharge port 4 side and the spread amount L from the adhesive application portion 18 to the adhesive escape portion 19 side are almost the same. If the cover plate 13 is then continuously pressed, the spread adhesive 22 reaches the portion where the adhesive escape portion 19 is provided, as shown in FIG. 8. Then, the adhesive 22 is drawn into the adhesive escape portion 19 by the capillary force of the adhesive escape portion 19, which is a recess. As a result, the amount of spread L1 of the adhesive 22 from the adhesive application section 18 toward the adhesive escape section 19 is greater than the amount of spread L2 from the adhesive application section 18 toward the discharge port 4. Therefore, as shown in FIG. 3, the adhesive 22 is prevented from reaching the discharge port 4 and its vicinity. The discharge port forming member 12 and the cover plate 13 are joined to each other by the adhesive 22 that has spread in this manner. At this time, an adhesive presence area 23 where the adhesive 22 is present and an adhesive avoidance area 24 where the adhesive 22 is not present are provided between the opposing surfaces 12a, 13a of the discharge port forming member 12 and the cover plate 13.

In this embodiment, the adhesive applying section 18 is provided along the discharge port row 4A at a position away from the discharge port 4. By applying the adhesive 22 to this adhesive applying section 18, uneven application of the adhesive 22 as shown in FIG. 4A can be suppressed. A large number of adhesive escape sections 19 are provided on the opposite side of the adhesive applying section 18 from the discharge port 4 and its vicinity, which is the adhesive avoidance area 24. The adhesive 22 is drawn and held inside the adhesive escape sections 19 by capillary force, thereby suppressing the amount of adhesive 22 flowing toward the discharge port 4. As a result, the adhesive 22 can be suppressed from entering the discharge port 4, forming the adhesive avoidance area 24, and preventing liquid discharge from becoming impossible or unstable.

In addition, the adhesive application portion 18 in this embodiment is a bottomed recess that does not penetrate the outlet forming member 12 and extends to the middle of the thickness direction of the outlet forming member 12 in a direction perpendicular to the outlet forming member 12. However, the adhesive application portion 18 may be formed as a through-hole portion that penetrates the outlet forming member 12 in a direction perpendicular to the outlet forming member 12. When the adhesive application portion 18 is a through-hole portion, a recess or hole portion that communicates with the adhesive application portion 18 may be formed at a position below the adhesive application portion 18 of the flow path forming member 11 or the substrate 10, although not shown. In addition, a recess that communicates with the adhesive application portion 18 may be formed at a position above the adhesive application portion 18 of the cover plate 13, although not shown. Similarly, the adhesive escape portion 19 may be a bottomed recess that extends to the middle of the thickness direction of the outlet forming member 12 in a direction perpendicular to the outlet forming member 12, or may be a through-hole portion that penetrates the outlet forming member 12 in a direction perpendicular to the outlet forming member 12. When the adhesive escape portion 19 is a through hole portion, a recess or hole portion communicating with the adhesive escape portion 19 may be formed below the adhesive escape portion 19 of the flow path forming member 11 or the substrate 10, although this is not shown. Also, a recess portion communicating with the adhesive escape portion 19 may be formed above the adhesive escape portion 19 of the cover plate 13, although this is not shown.

In this embodiment, the adhesive applicator 18 is a long, thin, linear groove extending in the longitudinal direction D1 of the outlet forming member 12, but it may also be a groove located to the side of the outlet row 4A and extending in the lateral direction D2 of the outlet forming member 12. Furthermore, the adhesive applicator 18 may have a shape in which a groove extending in the longitudinal direction D1 of the outlet forming member 12 is connected to a groove extending in the lateral direction D2. Furthermore, multiple adhesive applicators 18 may be arranged side by side along either or both of the longitudinal direction D1 and the lateral direction D2 of the outlet forming member 12.

In this embodiment, the adhesive escape portions 19 are arranged to form one or more rows 19A extending in the longitudinal direction D1 of the discharge port forming member 12. However, although not shown, they may be arranged to form one or more rows located to the side of the discharge port row 4A and extending in the lateral direction D2 of the discharge port forming member 12. Furthermore, the adhesive escape portions 19 may be arranged so that one or more rows extending in the longitudinal direction D1 of the discharge port forming member 12 and one or more rows extending in the lateral direction D2 are connected to each other. This configuration in which the adhesive escape portions 19 form rows extending in the lateral direction D2 is mainly adopted when the adhesive application portion 18 is located to the side of the discharge port row 4A. The shape, size, and number of the adhesive escape portions 19 may be appropriately set so that a sufficient amount of adhesive 22 can be drawn in by capillary force.

In this embodiment, when viewed in a direction perpendicular to the plate surface of the discharge port forming member 12, two adhesive applicators 18 are arranged substantially parallel to the discharge port array 4A on both sides of one discharge port array 4A at equal intervals from the discharge port array 4A. However, if two or more discharge port arrays 4A are arranged closely and parallel to each other (not shown), they may be regarded as one discharge port array group, and two adhesive applicators 18 may be arranged on both sides of the discharge port array group at equal intervals from the discharge port array group. The adhesive applicator 18 in this embodiment is a linear groove-like shape that is parallel to the discharge port array 4A and has the same length as the discharge port array 4A. In order to increase the density of the discharge ports 4 and to increase the functionality of the element substrate 5, it is desirable to reduce the width of the adhesive applicator 18 and the distance from the discharge port array 4A to minimize the space in which the discharge ports 4 and functional components cannot be arranged. However, the width of the adhesive application portion 18 and the distance from the discharge port array 4A are set appropriately taking into consideration the materials and physical properties of the discharge port forming member 12, the flow path forming member 11, the cover plate 13, the adhesive 22, etc., the presence or absence of a water repellent material, etc. In one example, when the diameter of the discharge port 4 is 20 μm and the distance (pitch) between the discharge ports 4 is 600 dpi, the width of the adhesive application portion 18 is 100 μm and the distance from the discharge port array 4A is 150 μm.

In this embodiment, the configuration of the present invention is adopted for the discharge port forming member 12 and the cover plate 13 so that the discharge port 4 of the liquid discharge head 1 and its vicinity become the adhesive avoidance area 24. However, the present invention is not limited to such a configuration. For example, the present invention is effective when a plate-shaped member on which an electric circuit or an electric component to which adhesive is not preferable is arranged is joined to another plate-shaped member via an adhesive to form a laminate. That is, the adhesive applying portion 18 and the adhesive escape portion 19 as described above are provided on the opposing surface of either or both of the plate-shaped member and the other plate-shaped member to be joined, and the adhesive applying portion 18 may be disposed between the position of the electric circuit or electric component and the adhesive escape portion 19. Specifically, it is desirable to avoid the adhesion of adhesive to the energy generating element 21 provided on the opposing surface of the substrate 10 to be joined to the flow path forming member 11, the electric circuit (not shown) including wiring connected thereto, and the pressure chamber 17 provided in the flow path forming member 11. The configuration of the present embodiment described above is also effective in preventing the adhesive 22 that bonds the ejection port forming member 12 and the cover plate 13 from contacting the energy generating element 21, the electric circuit, the pressure chamber 17, etc. of the substrate 10 and the flow path forming member 11. In addition, the adhesive applying portion 18 and the adhesive escape portion 19 may be provided on either or both of the opposing surfaces of the substrate 10 and the flow path forming member 11 on which the energy generating element 21, the electric circuit, the pressure chamber 17, etc. are provided, and the plate-like member bonded thereto. This prevents the adhesive for bonding the substrate 10 and the flow path forming member 11 themselves from adhering to the energy generating element 21, the electric circuit, and the pressure chamber 17. In recent liquid ejection heads 1, the number of functions has increased and the density of the ejection ports 4 has increased, so it is extremely effective that these configurations can ensure the adhesive avoidance area 24 without requiring a space larger than necessary.

(Suitable examples of adhesive relief portions)
A particularly preferred example of the adhesive escape portion 19 of this embodiment will be described. It is preferable that the adhesive escape portion 19 has a large capillary force for drawing the adhesive 22 inside. When the discharge port forming member 12 is turned upside down for some reason and the adhesive escape portion 19 opens vertically downward, it is preferable that a strong surface tension is generated so that the adhesive 22 in the adhesive escape portion 19 can be held without flowing vertically downward due to gravity. When the adhesive escape portion 19 is a circular hole with a circular surface shape of diameter d and the adhesive 22 is drawn to a position of height h inside the adhesive escape portion 19 by capillary force, the relationship between gravity acting on the adhesive 22 and surface tension σ is expressed by the following formula.
h = 4σ cosθ/dρg
is the density of the adhesive 22, g is the gravitational acceleration, and θ is the contact angle, which are values determined by the physical properties of the adhesive 22 and the discharge port forming member 12.

According to this formula, the retraction height h is inversely proportional to the diameter d, and the smaller the diameter d of the circle, the higher the retraction height h, which means that the force that retracts the adhesive 22 into the adhesive escape portion 19 is greater. When the increased retraction force and surface tension are balanced with gravity, the adhesive 22 can be retracted and held inside the adhesive escape portion 19 even when the adhesive escape portion 19 is in a position where it opens vertically downward, and contamination of the surroundings is suppressed. Even if the adhesive escape portion 19 has a polygonal planar shape instead of a circular shape, the tendency that the retraction height h increases as the dimensions of the planar shape become smaller remains the same. On the other hand, the amount of adhesive 22 that is retracted into the adhesive escape portion 19 by capillary action is the product of the planar shape area of the adhesive escape portion 19 and the retraction height h, and when the diameter d is reduced, the height h increases but the area of the planar shape decreases. Therefore, even if the diameter d of the adhesive escape portion 19 is reduced, it cannot be said that the amount of adhesive 22 drawn into the adhesive escape portion 19 is necessarily increased. Therefore, it is possible to increase the force that draws the adhesive 22 into each adhesive escape portion 19 and increase the total amount of adhesive 22 drawn into the adhesive escape portions 19 to reduce the amount of adhesive 22 flowing toward the discharge port 4. In other words, it is preferable to arrange many adhesive escape portions 19 with small planar shapes (small diameter d) at high density. In a suitable example, multiple adhesive escape portions 19 with circular planar shapes with a diameter d of 5 μm are arranged at intervals (pitch) of 5 μm.

In this embodiment, the adhesive escape portion 19 is disposed on the opposite side of the discharge port 4 from the adhesive application portion 18, and the row 19A of the multiple adhesive escape portions 19 is substantially parallel to the discharge port row 4A. Therefore, the adhesive application portion 18, the adhesive avoidance area 24 including the discharge port row 4A, and the multiple adhesive escape portion row 19A are positioned substantially parallel to each other. In order to more reliably guide the adhesive 22 to the adhesive escape portion 19, it is preferable to arrange the adhesive escape portions 19 so that many adhesive escape portions 19 are present along the direction in which the adhesive 22 spreads. In the example shown in Figures 5 to 8, the multiple adhesive escape portions 19 are arranged to form three rows 19A extending along the longitudinal direction D1 of the discharge port forming member 12. Specifically, the adhesive escape portions 19 are arranged in a staggered pattern with a spacing of 5 μm between each other, and the adhesive 22 spreads along the short-side direction D2 of the discharge port forming member 12 so as to cross the row 19A of the adhesive escape portions 19. In order to efficiently draw the adhesive 22 into the adhesive escape portions 19 by capillary force, it is preferable that the adhesive escape portions 19 are close to the adhesive application portions 18. As an example, the spacing (shortest distance) between the adhesive application portions 18 and the row 19A of adhesive escape portions is 5 μm. However, as described above, in order to arrange a large number of adhesive escape portions 19, the adhesive escape portions 19 may further be arranged in a row extending in a direction intersecting with the discharge port row 4A. In this case, too, it is preferable to arrange the adhesive escape portions 19 as densely as possible, as described above.

In this embodiment, the adhesive escape portion 19 is a recess having a circular planar shape, but is not limited to such a configuration. For example, the adhesive escape portion 19 may have a polygonal planar shape. In the modified example shown in FIG. 9, the discharge port forming member 12 is provided with a plurality of adhesive escape portions 19 having a rectangular planar shape. Even with adhesive escape portions 19 having such a planar shape, they have the effect of drawing in and holding the adhesive 22 by capillary force, just like adhesive escape portions 19 having a circular planar shape. Even with this configuration, it is preferable to arrange a large number of adhesive escape portions 19 having a small planar shape to increase the capillary force generated in each adhesive escape portion 19 while increasing the total amount of adhesive 22 drawn in and held by the multiple adhesive escape portions 19.

Second Embodiment
Next, a liquid ejection head 1 according to a second embodiment of the present invention will be described. Fig. 10(A) is a plan view of the liquid ejection head according to this embodiment, and Fig. 10(B) is an enlarged plan view of part C in Fig. 10(A). In this embodiment, as in the first embodiment, an adhesive application section 18 and a plurality of adhesive escape sections 19 are provided on the ejection port forming member 12, and the adhesive application section 18 is disposed between the region including the ejection port 4 (adhesive avoidance region 24) and the adhesive escape section 19. Furthermore, in this embodiment, auxiliary grooves 25 are disposed between the adhesive application section 18 and the adhesive avoidance region 24. The auxiliary grooves 25 are grooves that are smaller in planar shape than the adhesive application section 18 and larger in planar shape than the adhesive escape section 19, and are substantially parallel to the adhesive application section 18. Therefore, the adhesive application section 18, the adhesive avoidance region 24 including the ejection port row 4A, the plurality of adhesive escape section rows 19A, and the auxiliary grooves 25 are positioned substantially parallel to each other. The auxiliary groove 25 is provided to store the adhesive 22 in front of the discharge port 4 in cases where there is a possibility that the spread of the adhesive 22 towards the discharge port 4 side cannot be sufficiently suppressed by simply drawing the adhesive 22 into the adhesive escape portion 19 by capillary force. This is particularly effective in cases where there is insufficient space to form the adhesive escape portion 19 due to an increase in density of the discharge port 4 or an increase in the number of functions of the element substrate.

By providing the auxiliary groove 25 in addition to the adhesive escape portion 19, the adhesive 22 is more reliably prevented from entering the discharge port 4 and its vicinity. The auxiliary groove 25 is formed to reliably capture the spreading adhesive 22 in front of the discharge port 4, rather than drawing in the adhesive 22 using capillary action. For this reason, the auxiliary groove 25 is a groove with a large opening area, and as an example, has the same length as the adhesive application portion 18 and a width of 30 μm. However, the shape and dimensions of the auxiliary groove 25 can be set arbitrarily taking into consideration the physical properties and application amount of the adhesive 22, the size of the area in which the adhesive escape portion 19 is provided, and the like. The auxiliary groove 25 shown in FIG. 10 is a recess that does not penetrate the discharge port forming member 12, but may be formed as a through-hole portion that penetrates the discharge port forming member 12. When the auxiliary groove 25 is a through-hole portion, a recess or hole portion that communicates with the auxiliary groove 25 may be formed at a position below the auxiliary groove 25 of the flow path forming member 11 or the substrate 10, although not shown. In addition, although not shown, a recess communicating with the auxiliary groove 25 may be formed in a position above the auxiliary groove 25 of the cover plate 13. Other than the matters described above, the present embodiment is substantially the same as the first embodiment, so description and illustration will be omitted.

Third Embodiment
Next, a liquid ejection head 1 according to a third embodiment of the present invention will be described. Fig. 11 is a diagram showing a substrate 10 and a connection member 9, with a portion of the liquid ejection head according to this embodiment cut at a position corresponding to line E-E in Fig. 3B. In this embodiment, the structure of the present invention is adopted in the joint between the substrate 10 and the connection member 9 that constitutes a portion of the element substrate 5. The substrate 10 and the connection member 9 may be made of any material, such as a resin material, an inorganic material, a photosensitive resin material, or a semiconductor substrate, but in this embodiment, both are made of a silicon substrate. The adhesive 22 may be any adhesive, such as an epoxy resin adhesive or a polyimide resin adhesive, but in this embodiment, benzocyclobutene is used.

If the adhesive 22 gets into the connection opening 16 of the connection member 9, it becomes impossible or insufficient to supply and recover the liquid, so it is desirable to avoid adhesion of the adhesive 22. In other words, it is preferable to make the area including the connection opening 16 an adhesive avoidance area 24. In this embodiment, an adhesive application section 18 and a plurality of adhesive escape sections 19 similar to those in the first and second embodiments are formed on the opposing surface of the connection member 9 facing the substrate 10. Then, on the opposing surface between the connection member 9 and the substrate 10, the adhesive application section 18 is located between the adhesive escape section 19 and the adhesive avoidance area 24. With this configuration, it is possible to prevent the adhesive 22 from adhering to the connection opening 16 and its surroundings, and to ensure smooth flow of the liquid within the element substrate 5. This configuration is particularly effective when the density of the flow paths 14, 15 and the connection opening 16 is increased in accordance with the increased density of the ejection ports 4 of the liquid ejection head 1.

Fourth Embodiment
Next, a liquid ejection head 1 according to a fourth embodiment of the present invention will be described. FIG. 12 is a plan view showing the opposing surface of the substrate 10, which is a part of the liquid ejection head according to this embodiment, which is joined to the flow path forming member 11. In this embodiment, the structure of the present invention is adopted in the joining portion between the substrate 10, which constitutes a part of the element substrate 5, and the flow path forming member 11. The materials of the substrate 10, the flow path forming member 11, and the adhesive 22 may be the same as those described above. If the adhesive 22 adheres to the energy generating elements 21 formed on the substrate 10, it may affect the function of the energy generating elements 21, so it is preferable to avoid the adhesion of the adhesive 22. That is, it is preferable to make the area including the row 21A of the energy generating elements the adhesive avoidance area 24. In this embodiment, the adhesive application portion 18 and a plurality of adhesive escape portions 19 similar to those of the first and second embodiments are formed on the opposing surface of the substrate 10 facing the flow path forming member 11. Then, on the opposing surface between the substrate 10 and the flow path forming member 11, the adhesive application portion 18 is located between the adhesive escape portion 19 and the adhesive avoidance area 24. This configuration makes it possible to prevent the adhesive 22 from adhering to the energy generating elements 21 and their surroundings, thereby maintaining the functionality of the energy generating elements 21. This configuration is particularly effective in the case where the density of the energy generating elements 21 is increased in accordance with the increased density of the ejection ports 4 of the liquid ejection head 1.

(Action and Effect)
As described by way of example in the first to fourth embodiments, according to the present invention, the plate-like member to be joined by the adhesive 22 is provided with the adhesive application portion 18, which is a recess or hole, and the adhesive application portion 18 serves as a guide when applying the adhesive 22 to the plate-like member. This allows the adhesive 22 to be applied with good positional accuracy, and prevents uneven application as shown in FIG. 4(A). The adhesive escape portion 19 is provided on the opposite side of the adhesive avoidance region 24 from the adhesive application portion 18, and the adhesive 22 that has reached the adhesive escape portion 19 is drawn into the adhesive escape portion 19 by capillary action. As a result, a large amount of the adhesive 22 spreads to the adhesive escape portion 19 side, and the spread of the adhesive 22 to the adhesive avoidance region 24 side is suppressed. Therefore, while the plate-like member is firmly bonded to another plate-like member, it is possible to suppress the adhesive 22 from entering the portion (adhesive avoidance region 24) that is not to be touched by the adhesive 22. The present invention is not only effective in preventing the adhesive from penetrating into holes and recesses such as the ejection ports 4 and the connection openings 16 as in the first to third embodiments, but is also effective in protecting functional components such as the energy generating elements 21 from the adhesive. In this way, the ejection ports 4 are densely arranged, and the adhesive 22 can be applied with high precision even in a multi-functional liquid ejection head 1, making it possible to manufacture a high-quality liquid ejection head 1. However, the present invention is not limited to liquid ejection heads, and can be adopted in laminates of various plate-like members.

Disclosure of embodiments of the present invention includes the following configurations.
(Configuration 1)
A laminate including at least one pair of plate-like members stacked on each other,
The pair of plate-like members have opposing surfaces that face each other and are joined to each other by an adhesive, and have an adhesive presence region where an adhesive is present between the opposing surfaces of the pair of plate-like members, and an adhesive avoidance region where no adhesive is present;
an adhesive application portion which is a recess or a hole, and an adhesive escape portion which is a recess or a hole and has a smaller planar shape than the adhesive application portion are formed on the opposing surface of at least one of the pair of plate-shaped members;
A laminate, characterized in that, on the opposing surfaces of the pair of plate-like members, the adhesive application portion is located between the adhesive escape portion and the adhesive avoidance area.
(Configuration 2)
2. The laminate of claim 1, comprising a plurality of said adhesive relief portions.
(Configuration 3)
3. The laminate of claim 2, wherein the adhesive relief portions are arranged in one or more rows.
(Configuration 4)
4. The laminate of claim 3, wherein the adhesive relief portions are arranged in a staggered pattern.
(Configuration 5)
5. The laminate of claim 3 or 4, wherein the adhesive application portion is a linear groove, and the adhesive application portion, the adhesive avoidance area, and the row of the adhesive relief portions are positioned parallel to one another.
(Configuration 6)
A laminate described in any one of configurations 1 to 5, wherein an auxiliary groove is provided on the opposing surface of at least one of the pair of plate-shaped members, the auxiliary groove being located between the adhesive application portion and the adhesive avoidance area.
(Configuration 7)
The laminate of structure 6, wherein the adhesive application portion is a linear groove, and the adhesive application portion, the adhesive avoidance area, the auxiliary groove, and the row of the adhesive escape portions are positioned parallel to one another.
(Configuration 8)
8. The laminate according to claim 6 or 7, wherein the auxiliary groove has a planar shape smaller than that of the adhesive application portion and larger than that of the adhesive escape portion.
(Configuration 9)
9. The laminate according to any one of configurations 1 to 8, wherein the adhesive relief portion is a recess having a circular planar shape and extending partway through a thickness direction of the plate-like member in a direction perpendicular to the plate-like member in which the adhesive relief portion is provided.
(Configuration 10)
10. The laminate of any one of claims 1 to 9, wherein the adhesive relief portion has a circular planar shape and is a hole portion that penetrates the plate-like member in a direction perpendicular to the plate-like member in which the adhesive relief portion is provided.
(Configuration 11)
11. The stack of any one of claims 1 to 10, wherein the pair of plate-like members are both made of silicon substrates.
(Configuration 12)
a multi-layered element substrate having a pressure chamber to which liquid is supplied, a discharge port connected to the pressure chamber and opening toward the outside, and an energy generating element for supplying energy to the liquid inside the pressure chamber;
12. A liquid ejection head, wherein the element substrate is the laminate according to any one of configurations 1 to 11, and at least a portion of the element substrate is made of the pair of plate-like members.
(Configuration 13)
13. The liquid ejection head according to configuration 12, wherein the pair of plate-like members is an ejection port forming member and a cover plate, and the adhesive avoidance area is an area including the ejection port.
(Configuration 14)
13. The liquid ejection head according to configuration 12, wherein the pair of plate-like members is a connection member and a substrate, and the adhesive avoidance area is an area including a connection opening.
(Configuration 15)
13. The liquid ejection head according to configuration 12, wherein the pair of plate-like members is a substrate and a flow path forming member, and the adhesive avoidance area is an area including the energy generating elements.
(Configuration 16)
16. A liquid ejection apparatus comprising: the liquid ejection head according to any one of configurations 12 to 15; and a transport mechanism that transports a recording medium so as to pass a position facing the ejection openings.
(Method 1)
A method for producing a laminate including at least one pair of plate-like members stacked on top of each other, comprising the steps of:
At least one of the pair of plate-like members is formed with an adhesive-applying portion which is a recess or a hole, and an adhesive-releasing portion which is a recess or a hole and has a smaller planar shape than the adhesive-applying portion,
applying an adhesive to the adhesive application section;
stacking the pair of plate-like members on each other such that the surface on which the adhesive application portion to which the adhesive is applied faces the other plate-like member;
a step of spreading the adhesive applied to the adhesive application section between the pair of plate-like members and bonding the pair of plate-like members to each other by the spread adhesive;
Including,
A method for manufacturing a laminate, characterized in that when spreading the adhesive in a process of joining the pair of plate-like members to each other, a portion of the adhesive enters the adhesive escape portion, and an adhesive avoidance area into which the adhesive has not entered is provided on the opposing opposing surfaces of the pair of plate-like members on the opposite side to the adhesive escape portion as viewed from the adhesive application portion.
(Method 2)
A method for manufacturing a liquid ejection head, comprising the steps of the method for manufacturing a laminate described in Method 1, characterized in that the pair of plate-like members are an ejection port forming member and a cover plate, and the adhesive avoidance area is an area including an ejection port.
(Method 3)
A method for manufacturing a liquid ejection head, comprising the steps of the method for manufacturing a laminate described in Method 1, characterized in that the pair of plate-like members are a connecting member and a substrate, and the adhesive avoidance area is an area including a connecting opening.
(Method 4)
A method for manufacturing a liquid ejection head, comprising the steps of the method for manufacturing a laminate described in Method 1, characterized in that the pair of plate-like members are a substrate and a flow path forming member, and the adhesive avoidance area is an area including an energy generating element.

12 Discharge port forming member (plate-shaped member)
13 Cover plate (plate-shaped member)
18 adhesive application portion 19 adhesive escape portion 22 adhesive 23 adhesive presence region 24 adhesive avoidance region

Claims (20)

A laminate including at least one pair of plate-like members stacked on each other,
The pair of plate-like members have opposing surfaces that face each other and are joined to each other by an adhesive, and have an adhesive presence region where an adhesive is present between the opposing surfaces of the pair of plate-like members, and an adhesive avoidance region where no adhesive is present;
an adhesive application portion which is a recess or a hole, and an adhesive escape portion which is a recess or a hole and has a smaller planar shape than the adhesive application portion are formed on the opposing surface of at least one of the pair of plate-shaped members;
A laminate, characterized in that, on the opposing surfaces of the pair of plate-like members, the adhesive application portion is located between the adhesive escape portion and the adhesive avoidance area. The laminate according to claim 1, having a plurality of the adhesive relief portions. The laminate according to claim 2, wherein the adhesive relief portions are arranged in one or more rows. The laminate according to claim 3, wherein the adhesive relief portions are arranged in a staggered pattern. The laminate according to claim 3 or 4, wherein the adhesive application portion is a linear groove, and the adhesive application portion, the adhesive avoidance area, and the row of the adhesive escape portions are positioned parallel to one another. The laminate according to any one of claims 1 to 4, wherein an auxiliary groove is provided on the opposing surface of at least one of the pair of plate-like members, the auxiliary groove being located between the adhesive application portion and the adhesive avoidance area. The laminate according to claim 6, wherein the adhesive application portion is a linear groove, and the adhesive application portion, the adhesive avoidance area, the auxiliary groove, and the row of the adhesive escape portions are positioned parallel to one another. The laminate according to claim 6, wherein the auxiliary groove has a smaller planar shape than the adhesive application portion and a larger planar shape than the adhesive escape portion. The laminate according to any one of claims 1 to 4, wherein the adhesive escape portion is a recess that has a circular planar shape and extends partway through the thickness direction of the plate-like member in a direction perpendicular to the plate-like member on which the adhesive escape portion is provided. The laminate according to any one of claims 1 to 4, wherein the adhesive escape portion has a circular planar shape and is a hole that penetrates the plate-like member in a direction perpendicular to the plate-like member on which the adhesive escape portion is provided. The laminate according to any one of claims 1 to 4, wherein the pair of plate-like members are both made of silicon substrates. a multi-layered element substrate having a pressure chamber to which liquid is supplied, a discharge port connected to the pressure chamber and opening toward the outside, and an energy generating element for supplying energy to the liquid inside the pressure chamber;
5. A liquid ejection head, wherein the element substrate is the laminate according to claim 1, and at least a part of the element substrate is made of the pair of plate-like members. The liquid ejection head according to claim 12, wherein the pair of plate-like members is an ejection port forming member and a cover plate, and the adhesive avoidance area is an area including the ejection port. The liquid ejection head according to claim 12, wherein the pair of plate-like members is a connection member and a substrate, and the adhesive avoidance area is an area including a connection opening. The liquid ejection head according to claim 12, wherein the pair of plate-like members is a substrate and a flow path forming member, and the adhesive avoidance area is an area including the energy generating element. A liquid ejection device including the liquid ejection head according to claim 12 and a transport mechanism that transports a recording medium through a position facing the ejection port. A method for producing a laminate including at least one pair of plate-like members stacked on top of each other, comprising the steps of:
At least one of the pair of plate-like members is formed with an adhesive-applying portion which is a recess or a hole, and an adhesive-releasing portion which is a recess or a hole and has a smaller planar shape than the adhesive-applying portion,
applying an adhesive to the adhesive application section;
stacking the pair of plate-like members on each other such that the surface on which the adhesive application portion to which the adhesive is applied faces the other plate-like member;
a step of spreading the adhesive applied to the adhesive application section between the pair of plate-like members and bonding the pair of plate-like members to each other by the spread adhesive;
Including,
A method for manufacturing a laminate, characterized in that when spreading the adhesive in a process of joining the pair of plate-like members to each other, a portion of the adhesive enters the adhesive escape portion, and an adhesive avoidance area into which the adhesive has not entered is provided on the opposing opposing surfaces of the pair of plate-like members on the opposite side to the adhesive escape portion as viewed from the adhesive application portion. A method for manufacturing a liquid ejection head, comprising the steps of the method for manufacturing a laminate described in claim 17, characterized in that the pair of plate-like members are an ejection port forming member and a cover plate, and the adhesive avoidance region is a region that includes the ejection port. A method for manufacturing a liquid ejection head, comprising the steps of the method for manufacturing a laminate according to claim 17, wherein the pair of plate-like members are a connection member and a substrate, and the adhesive avoidance region is a region including a connection opening. A method for manufacturing a liquid ejection head, comprising the steps of the method for manufacturing a laminate described in claim 17, characterized in that the pair of plate-like members are a substrate and a flow path forming member, and the adhesive avoidance area is an area including an energy generating element.

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