JP2010005993A - Substrate joining method, joined substrate, inkjet head, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a separation of a joined part due to a warpage of a substrate and thereby to achieve a joining with a high dimensional precision. <P>SOLUTION: A substrate joining method for joining a first and second substrates by using a plurality of adhesives having different flexibilities includes: a machining step of forming grooves or holes at least in either of the first and second substrates; an applying position determining step of determining applying positions of the adhesives to the joining surfaces between the first and second substrates, according to a warpage state of the substrate where the grooves or the holes are formed; an applying step of applying the adhesives to the joining surface of the first or second substrate, according to the applying positions of the adhesives, determined in the applying position determining step; and a joining step of joining the first and second substrates via the adhesives, and of curing the adhesives. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a substrate bonding method, a substrate bonded body, an ink jet head, and an image forming apparatus, and more particularly to a technique for bonding substrates using a plurality of adhesives having different flexibility.

  The ink jet recording method is a method of recording by discharging ink droplets from a plurality of nozzles formed on an ink jet head toward a recording medium. The noise during the recording operation is low, the running cost is low, and the high resolution is achieved. Images and high-quality image recording are possible. As an ink ejection method, there are a piezoelectric method using displacement of a piezoelectric element, a thermal method using thermal energy generated by a heating element, and the like.

  In such an ink jet head, a structure in which substrates are bonded to each other using an adhesive is widely adopted. However, warpage is likely to occur in a substrate in which a groove or hole serving as an ink flow path is processed, and when a substrate with such warpage is bonded with an adhesive, stress due to the warpage of the substrate is applied to the adhesive. become. Usually, an adhesive having a strength that can withstand stress is used. However, in the case of a structure in which the adhesive is in contact with ink, such as an inkjet head, the strength of the adhesive is reduced by being in contact with the ink. Peeling is likely to occur at the part. In addition, if there is a defective portion in the adhesive due to entrainment of bubbles or the like, stress concentrates on the defective portion, and therefore peeling is likely to occur particularly in an adhesive that lacks flexibility.

  In addition, when bonding is performed only with an adhesive having flexibility (excellent flexibility), the desired dimensional accuracy can be obtained even if the adhesive is deformed due to stress caused by warping of the substrate and does not peel off. There is also a problem that cannot be done.

  On the other hand, a technique for bonding substrates using a plurality of adhesives is disclosed (for example, see Patent Document 1).

In Patent Document 1, a fixed reference FP is set at the same position on a bonding surface of a plurality of head units, and a first adhesive U1 is applied in the vicinity of the fixed reference FP to form a first adhesive bonded portion. At the same time, a second adhesive joint portion is formed by applying a second adhesive U2 having a smaller elastic modulus than the first adhesive U1 to a region excluding the vicinity of the fixed reference FP, and the first and second adhesive joints are formed. A droplet discharge head is described in which each head unit is bonded and fixed to a long substrate by a bonding portion.
JP 2008-940000 A

  However, Patent Document 1 aims at positioning and fixing a plurality of head units to a base substrate with high accuracy and suppressing negative reversible displacement of the head unit due to a temperature change. It has not been.

  For this reason, the technique disclosed in Patent Document 1 cannot prevent the adhesion portion from being peeled off or the dimensional accuracy from being lowered.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances. A substrate bonding method, a substrate bonded body, and an ink jet head that can prevent bonding from being peeled off due to substrate warpage and realize bonding with high dimensional accuracy. And an image forming apparatus.

  In order to achieve the above object, a substrate bonding method according to the present invention is a substrate bonding method for bonding a first substrate and a second substrate using a plurality of adhesives having different flexibility. According to a processing step of forming a groove or a hole in at least one of the second substrates, and a warping state of the substrate in which the groove or the hole is formed, the plurality of the bonding surfaces of the first or second substrate. According to the application position determination step of determining the application position of the adhesive and the application positions of the plurality of adhesives determined according to the warpage state of the substrate on which the groove or hole is formed. An application step of applying the plurality of adhesives to a bonding surface of the substrate, and a bonding step of bonding the first and second substrates via the plurality of adhesives and curing the plurality of adhesives. And including.

  According to the present invention, when bonding the first and second substrates using a plurality of adhesives having different flexibility, each adhesion determined according to the warpage state of the substrate in which the groove or the hole is formed. By applying each adhesive to the bonding surface of the first or second substrate according to the application position of the agent, it is possible to prevent peeling of the bonded portion due to the warp of the substrate, and the substrates are dimensional accuracy Can be joined well.

  In the present invention, it is preferable to include a surface treatment step of performing a surface treatment on the bonding surfaces of the first and second substrates before the coating step is performed. By performing surface treatment such as cleaning and surface modification on the bonding surfaces of the first and second substrates, the adhesive force of each adhesive can be improved.

  Further, in the present invention, the application position determining step includes a step of detecting a warpage state of the substrate on which the groove or hole is formed by obtaining a distance between the first and second substrates. Is preferred. Further, among the plurality of adhesives, when the first flexible adhesive is used as the first adhesive and the second adhesive is used as the second flexible adhesive, the application position determining step includes: It is preferable that a portion where the distance between the first and second substrates is larger than a reference value is a position where the first adhesive is applied, and a portion where the distance is smaller than the reference value is a position where the second adhesive is applied. . The application position of each adhesive can be easily determined.

  In the present invention, the plurality of adhesives are preferably epoxy adhesives from the viewpoints of adhesive strength and liquid resistance. Furthermore, it is preferable that the plurality of adhesives are made of the same epoxy resin and have different amounts of flexibility imparting agents or different materials. In this case, since the physical property values of the adhesives are close, it is possible to apply and cure the adhesives under the same conditions, leading to a reduction in man-hours.

  In order to achieve the above object, a substrate joined body according to the present invention is a substrate joined body composed of first and second substrates joined by a plurality of adhesives having different flexibility. Grooves or holes are formed in at least one of the first and second substrates, and among the plurality of adhesives, a highly flexible adhesive is used as the first adhesive, and a low flexible adhesive is used as the first adhesive. When the adhesive of No. 2 is used, a portion where the stress applied to the adhesive at the joint portion of the first and second substrates is larger than a reference value is joined by the first adhesive, and a portion smaller than the reference value is It is characterized by being joined by a second adhesive.

  According to the present invention, the portion where the stress applied to the adhesive at the joint between the first and second substrates is larger than the reference value is joined with the highly flexible adhesive (first adhesive), and the reference value Since the smaller portion is bonded with a flexible adhesive (second adhesive), the bonded portion is hardly peeled off, and a substrate assembly having high durability can be realized.

  In the present invention, the plurality of adhesives are preferably epoxy adhesives from the viewpoints of adhesive strength and liquid resistance. Furthermore, it is preferable that the plurality of adhesives are made of the same epoxy resin and have different amounts of flexibility imparting agents or different materials. In this case, since the physical property values other than the flexibility of the adhesive are close to each other, a problem hardly occurs even when heat is applied (similarly, each adhesive expands and contracts).

  In order to achieve the above object, an ink jet head according to the present invention includes the above-mentioned substrate bonded body. An ink jet head having excellent durability can be realized.

  In order to achieve the above object, an image forming apparatus according to the present invention includes the inkjet head. An image forming apparatus having excellent durability can be realized.

  According to the present invention, when bonding the first and second substrates using a plurality of adhesives having different flexibility, each adhesion determined according to the warpage state of the substrate in which the groove or the hole is formed. By applying each adhesive to the bonding surface of the first or second substrate according to the application position of the agent, it is possible to prevent peeling of the bonded portion due to the warp of the substrate, and the substrates are dimensional accuracy Can be joined well.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Description of adhesive]
First, the adhesive used in the present invention will be described.

  In the present invention, a plurality of adhesives having different flexibility are used.

  In this specification, “flexibility (flexibility)” means the difficulty of breaking when stress is applied, and the magnitude relationship of flexibility is relative. To be determined. Therefore, an adhesive with high flexibility (excellent flexibility) is less likely to break even when stress is applied (breaking strength is lower) than an adhesive with low flexibility (inferior flexibility). It is an adhesive made of a large material. If another expression is used, it can be said that an adhesive having high flexibility is an adhesive having toughness or toughness. Moreover, you may use a Young's modulus or a fracture toughness value as a parameter | index which compares the magnitude of the flexibility (flexibility) with respect to an adhesive agent.

  The adhesive used in the present invention can be appropriately selected from silicon adhesives, epoxy adhesives, and other various materials. However, since the silicon adhesive has low resistance to alkalis and solvents, it is preferable to use an epoxy adhesive from the viewpoint of adhesive strength, liquid resistance, and the like.

  Regarding various epoxy materials, JP 2002-302591 A (paragraphs [0010] to [0011]), JP 2003-238770 A (paragraphs [0030] to [0036]), JP 2002-254660 A ( It is possible to use what is disclosed in paragraph [0038]).

  Among epoxy materials, bisphenol A type epoxy resin and bisphenol F type resin are preferable because of good curability and ink resistance. In particular, bisphenol A type epoxy resins are preferred because they have a wide variety of commercially available resins and can be used properly according to the required characteristics.

  In addition, as a method for imparting flexibility to an epoxy-based adhesive, “development of functional adhesive and latest technology (first volume) —Recent advances in structural bonding” (CMC Corporation, June 30, 1997) 63, JP 2002-302591 (paragraph [0012], JP 2003-238770 (paragraphs [0037] to [0038]), JP 2002-254660 (paragraph [0043]). ) Can be used.

  As a method for imparting flexibility, there is a method in which a bisphenol A type epoxy resin modified with an elastomer is mixed with an adhesive. In this case, the ink resistance is good and the adhesive strength can be increased, which is preferable.

  In the present invention, it is preferable that the plurality of adhesives having different flexibility are made of the same epoxy resin, and the amount of the flexibility imparting agent or the adhesive having different materials is different. In this case, since the physical property values of the adhesives are close, it is possible to apply and cure the adhesives under the same conditions, leading to a reduction in man-hours.

  In the case of changing the amount of the flexibility imparting agent, for example, an adhesive in which the amount of the elastomer-modified epoxy resin is changed from 10 to 40 wt% may be used. When changing the material of the flexibility imparting agent, the type of polymer material mixed with the epoxy resin or the type of curing agent is changed. More preferable is a method of changing the mixing amount, which allows easy adjustment of flexibility.

According to an experiment conducted by the present inventor, when silicon substrates were joined to each other and a tensile strength test was conducted, under the bonding conditions where the strength was about 100 kgf / cm ² , the ink was not removed when the head member was actually bonded. No leakage occurred, but when the head member was bonded under the condition of about 60 kgf / cm ² , ink leakage occurred. Therefore, when a flexibility imparting agent is mixed with the adhesive, it is preferable to mix so that the tensile strength exceeds 100 kgf / cm ² . However, the actually required strength needs to be appropriately determined depending on the shape of the bonded portion of the head, the bonding method, and the stress.

  Moreover, it is possible to use the adhesive which has UV sclerosis | hardenability or thermosetting as an adhesive agent. A mode in which substrates are bonded to each other using a thermosetting adhesive when UV light cannot be sufficiently applied to the adhesive depending on the type of substrate (for example, when an opaque substrate that does not transmit UV light is used). Is desirable. However, it is necessary to determine the heating temperature (curing temperature) of the adhesive according to the thermal expansion coefficient of the substrate. Care must be taken when bonding substrates having different coefficients of thermal expansion because the substrates warp due to heating. In addition, such a problem does not arise when the substrates having the same thermal expansion coefficient are joined.

  In the present invention, the adhesive is not limited to two types, and may be three or more types. Moreover, you may add an organic or inorganic filler to an adhesive agent for viscosity adjustment.

[Board bonding method]
Next, the substrate bonding method according to the present invention will be described.

  FIG. 1 is a process diagram showing an example of a substrate bonding method according to the present invention. The substrate bonding method shown in FIG. 1 uses the first adhesive S1 and the second adhesive S2 having different flexibility (however, the first adhesive S1 is more flexible than the second adhesive). 1), a substrate bonding method for bonding the first substrate 100 and the second substrate 102, in which the groove portion 100A is formed in the first substrate 100 (FIG. 1A). According to the surface treatment process (FIG. 1B) for performing surface treatment on the bonding surface of the first substrate 100 and the second substrate 102, and the warpage state of the first substrate 100 in which the groove 100A is formed. According to the application position determining step for determining the application position of each adhesive S1, S2 with respect to the bonding surface of the first substrate 100 or the second substrate 102, and the warpage state of the first substrate 100 in which the groove 100A is formed. According to the application positions of the adhesives S1 and S2 determined Application step (FIG. 1C) for applying the adhesives S1 and S2 to the bonding surface of the substrate 100 or the second substrate 102, and the first substrate 100 and the second substrate 102 to each adhesive. It includes a bonding step (FIG. 1 (d)) in which the adhesives S1 and S2 are cured by bonding via S1 and S2. The first substrate 100 and the second substrate 102 are members corresponding to thin plate laminated members such as a flow path forming substrate constituting an ink flow path (pressure chamber, supply port, etc.) formed in an ink jet head described later. It is.

  First, as shown in FIG. 1A, a groove 100 </ b> A is formed in the first substrate 100. Here, a case where the first substrate 100 in which the groove 100A is formed warps in a convex shape on the side opposite to the bonding surface (the lower side in the drawing) will be described. Whether the substrate warps upwardly or downwardly depends on the initial internal stress of the substrate, the strain due to processing, and the like.

  Examples of dimensions of the first substrate 100 are, for example, a thickness of 0.1 mm to 1 mm, a length of 10 to 30 mm, and a width of 30 to 70 mm, and the amount of warpage of the substrate is 0.01 to 0.1 mm.

  Various materials can be selected as the material of the first substrate 100, but among them, it is preferable that the material is made of a brittle material such as silicon or a material such as metal. When the first substrate 100 is made of a brittle material such as silicon or a material such as a metal, the adhesive is caused by deformation of the substrate as compared with a case where the first substrate 100 is made of a relatively soft material (small Young's modulus) such as a resin. Since the stress applied to the film becomes relatively large, the effects of the present invention can be exhibited more remarkably.

  The formation method of the groove 100A may be appropriately selected according to the material of the first substrate 100. For example, when the first substrate 100 is made of silicon, a highly accurate flow path structure can be formed by a method such as wet etching or dry etching.

  After forming the groove portion 100A in the first substrate 100 in this way, a surface treatment is performed on the bonding surfaces of the first substrate 100 and the second substrate 102 as shown in FIG. There are various surface treatment methods such as cleaning and surface modification.

  There are various cleaning methods such as UV cleaning, cleaning with ozone, oxygen plasma cleaning, ultrasonic cleaning, degreasing with a chemical solution, cleaning with a supercritical fluid, etc., which are appropriately selected according to the material and dirt state of each of the substrates 100 and 102. do it. Among these, UV cleaning and ultrasonic cleaning are preferable as relatively simple and effective methods.

  As a method for modifying the surface, there is a silane coupling treatment for improving adhesion. That is, the substrate surface is treated with a silane coupling agent. Moreover, you may mix a silane coupling agent with an adhesive agent.

  Examples of the silane coupling agent include JP 2002-302591 A (paragraph [0019]), JP 2003-238770 A (paragraphs [0063] to [0064]), and JP 2002-254660 A (paragraph). [0045]) may be used.

  Examples of silane coupling agents include amino silane coupling agents and epoxy silane coupling agents. For example, amino silane coupling agents include N- (2-aminoethyl) -3-aminopropyltrimethoxy. For silane, 3-aminopropyltriethoxysilane, and epoxy-based silane coupling agents, 3-glycidoxypropyltrimethoxysilane is used. However, when a silane coupling agent is treated on the substrate surface, either amino or epoxy silane coupling agents may be used, but when mixed with an adhesive, the amino silane coupling agent is In order to adversely affect the curing of the adhesive, an epoxy silane coupling agent is preferably used. Epoxy silane coupling agents can be easily blended with epoxy adhesives and can improve adhesive strength. When mixing with an adhesive, about 0.1 to 5 wt% is mixed. If the mixing amount is small, the effect of improving the adhesive strength cannot be obtained, and if it is large, the silane coupling agent becomes an uncured portion in the epoxy resin and the adhesive strength is reduced.

  Next, the application positions of the adhesives S1 and S2 on the bonding surface of the first substrate 100 or the second substrate 102 are determined according to the warpage state of the first substrate 100 in which the groove 100A is formed. Here, the adhesives S <b> 1 and S <b> 2 are applied to the bonding surface of the first substrate 100.

  As a method for determining the application position of each of the adhesives S1 and S2, first, using a laser displacement meter or the like, the first substrate 100 in which the groove 100A is formed is arranged so as to be substantially parallel to the second substrate 102. Then, the warpage state of the first substrate 100 is measured by obtaining the inter-substrate distance at each position of the first substrate 100 and the second substrate 102.

  Then, a portion where the distance between the substrates at each position of the first substrate 100 and the second substrate 102 is larger than the reference value (that is, a portion where a large stress is applied to the adhesive after joining) is a highly flexible first. A position where the distance between the substrates is smaller than the reference value is set as a position where the second adhesive S2 having a low flexibility is applied. The portion where the distance between the substrates is the same as the reference value may be the application position of either the first adhesive S1 or the second adhesive S2, and the adhesive to be applied may be determined in advance.

  In this example, since the first substrate 100 is convex on the side opposite to the bonding surface (see FIG. 1A), the stress applied to the adhesive at the bonding portion in the first substrate 100 is high. The joint surface central portion side that is larger than the reference value is the application position of the first adhesive S1, and the joint surface end portion side where the stress applied to the adhesive in the joint portion is smaller than the reference value is the application position of the second adhesive S2. It becomes.

  As said reference value, the average value of the distance between board | substrates can be used, for example. In addition, when the average value of the distance between the substrates is such that the application area (adhesion area) of the first flexible adhesive S1 having a large flexibility becomes too large and a desired dimensional accuracy cannot be obtained, for example, The reference value may be 80% of the maximum value of the distance between the substrates. When the reference value is 80% of the maximum value of the distance between the substrates, the portion where the distance between the substrates is 100 to 80% at each position of the first substrate 100 and the second substrate 102 is the first adhesion. The application position of the agent S1 is set, and the 80% to 0% portion is the application position of the second adhesive S2.

  As another method, the stress applied to the adhesive after joining is obtained by simulation from the measurement and material of the warp of the substrate, and the application position of each adhesive S1, S2 is determined according to the value of the stress. May be. If the stress at which the adhesive breaks is determined in a separate experiment, the adhesive can be used finely according to the stress. In addition, it is possible to use an adhesive having excellent flexibility at a portion exceeding 80% of the maximum stress. As described above, according to the method of obtaining the stress by simulation, the stress applied to the adhesive is obtained, and therefore, what kind of adhesive is used for which portion can be surely obtained.

  However, the method for obtaining the stress by simulation requires expensive software for accurate simulation and takes time, which causes an increase in cost. On the other hand, according to the method of determining the application positions of the adhesives S1 and S2 by comparing the distance between the substrates at each position of the first substrate 100 and the second substrate 102 and the reference value, each adhesive The application positions of S1 and S2 can be easily determined.

  Next, as shown in FIG. 1D, according to the application positions of the adhesives S1 and S2 determined according to the warpage state of the first substrate 100 in which the groove 100A is formed, the first substrate 100 ( Alternatively, the first adhesive S1 and the second adhesive S2 having different flexibility are applied to the joint surface of the second substrate 102).

  FIG. 2 is a diagram showing an example of application by a dispenser. As shown in FIG. 2, the adhesives S <b> 1 and S <b> 2 can be applied to the bonding surface of the first substrate 100 using the dispenser 110.

  FIG. 3 shows an example of the transfer method. In the transfer method, first, as shown in FIG. 3A, the adhesives S1 and S2 are dropped on a sheet 120 such as PET. Subsequently, as shown in FIG. 3B, the adhesives S1 and S2 are thinned and thinned with a bar coater. Then, as shown in FIG. 3C, the adhesives S <b> 1 and S <b> 2 thinned on the sheet 120 are transferred to the bonding surface of the first substrate 100. FIG.3 (d) is sectional drawing which follows the AA line in FIG.3 (c). In this way, the adhesives S1 and S2 can be applied to the bonding surface of the first substrate 100.

  As a method for applying each of the adhesives S1 and S2, screen printing, spin coating, spray coating, or the like can be applied in addition to the above-described application or transfer method using a dispenser. From these methods, an optimal method may be appropriately selected according to the properties of the adhesive (viscosity, thixotropy, etc.), the application position (range) and shape of the adhesive to the bonding surface of the substrate, and the like. For example, when the adhesive has a low viscosity and is flat and solid, spin coating is preferred. In addition, spray coating is preferable when the bonding surface of the substrate is uneven. Moreover, when apply | coating several places to island shape, application | coating by a dispenser and screen printing are preferable. Moreover, when the application part is a convex part, a transfer method is preferable.

  And finally, as shown in FIG.1 (d), the 1st board | substrate 100 and the 2nd board | substrate 102 are joined via each adhesive agent S1, S2, and each adhesive agent S1, S2 is hardened.

  When each adhesive agent S1 and S2 has thermosetting property, it pressurizes and heats in the state which each board | substrate 100 and 102 joined. The load (pressing force) at the time of pressurization may be determined according to the material, structure, type of adhesive, etc. of the substrates 100 and 102.

  Further, when each of the adhesives S1 and S2 has UV curable properties, UV light irradiation may be performed instead of heating. At this time, from the viewpoint of reliably irradiating each adhesive S1, S2 with UV light, at least one of the first substrate 100 and the second substrate 102 is made of a transparent substrate that transmits UV light. Is preferred.

  In this manner, a substrate bonded body 150 including the first substrate 100 and the second substrate 102 can be obtained.

  According to the substrate bonding method according to the present embodiment, when the first substrate 100 and the second substrate 102 are bonded using the plurality of adhesives S1 and S2 having different flexibility, the first groove 100A is formed. Since the adhesives S1 and S2 are applied to the bonding surface of the first substrate 100 or the second substrate 102 according to the application positions of the adhesives S1 and S2 determined according to the warpage state of the first substrate 100, The portion where the stress applied to the adhesive at the joint between the first substrate 100 and the second substrate 102 is large is joined with the first adhesive S1 having excellent flexibility, and the stress applied to the adhesive at the joint is increased. Small portions can be joined with the second adhesive S2 which is inferior in flexibility. Therefore, peeling of the bonded portion due to the warpage of the substrates can be prevented, and the substrates can be bonded with high dimensional accuracy.

  In the present embodiment, the case where the first substrate 100 in which the groove portion 100A is formed warps in a convex shape on the lower side (the side opposite to the bonding surface) (see FIG. 1) is not limited thereto. The present invention can be applied in the same manner to the case where the projection warps upward (joint surface side).

  FIG. 4 is a diagram illustrating a substrate bonding method in the case where the first substrate 100 in which the groove portion 100A is formed warps upward. As shown in FIG. 4A, when the first substrate 100 in which the groove 100A is formed warps upward (bonding surface side), the first substrate 100 bonding surface end portion side is changed to the first substrate 100. The application position of the first adhesive S1 is the application position of the first adhesive S1, the center of the joint surface is the application of the second adhesive S2, and the first substrate 100 ( Alternatively, the adhesives S1 and S2 are applied to the bonding surface of the second substrate 102). And as shown in FIG.4 (b), the board | substrate bonded body 150 can be obtained by joining the 1st board | substrate 100 and the 2nd board | substrate 102. FIG.

  In the present embodiment, the case where the groove 100A is formed in the first substrate 100 has been described. However, the present invention is not limited to this, and the case where the hole (through hole) 100B is formed in the first substrate 100 ( Also in FIG. 5 (a), as shown in FIG. 5 (b), it warps in a convex shape on the lower side (opposite to the joint surface), or on the upper side (joint surface side) as shown in FIG. 5 (c). Therefore, the present invention can be applied in the same manner. Of course, the present invention can be similarly applied to the case where both the groove 100A and the hole 100B are formed in the first substrate 100. In the present embodiment, not the first substrate 100 but the second substrate 102 may be formed with grooves or holes, or both. Needless to say, a groove portion or a hole portion or both of them may be formed for each of the first substrate 100 and the second substrate 102. In any case, the effects of the present invention can be exhibited more remarkably.

  In this embodiment, two types of adhesives are used as the plurality of adhesives having different flexibility. However, the present invention is not limited to this, and three or more types of adhesives may be used.

  FIG. 6 is a diagram illustrating a substrate bonding method in the case where the first substrate 100 and the second substrate 102 are bonded using three types of adhesives S1 'and S2' S3 'having different flexibility. Here, the first adhesive S1 ', the second adhesive S2', and the third adhesive S3 'are in order from the adhesive having the highest flexibility.

  As shown in FIG. 6A, in the case where the first substrate 100 in which the groove 100A is formed warps convexly downward (opposite to the bonding surface), each adhesive S1 ′, S2 ′ S3. When determining the application position of ', when the first reference value is 80% of the maximum value of the distance between the substrates and the second reference value is 20%, the distance between the substrates is the first reference value. A portion larger than the value (100 to 80%) is set as the application position of the first adhesive S1 ′, and a portion smaller than the first reference value and larger than the second reference value (80 to 20%) is the second position. The application position of the adhesive S2 ′ may be set, and a portion (20 to 0%) smaller than the second reference value may be set as the application position of the third adhesive S3 ′. Then, according to the application positions of the adhesives S1 ′, S2 ′, S3 ′ determined in this way, the adhesives S1 ′, S2 ′, S3 ′ are applied, and as shown in FIG. The substrate bonded body 150 can be obtained by bonding the substrate 100 and the second substrate 102.

[Overall configuration of inkjet recording apparatus]
Next, an ink jet recording apparatus which is an embodiment of the image forming apparatus according to the present invention will be described.

  FIG. 7 is an overall configuration diagram showing the ink jet recording apparatus according to the present embodiment. As shown in the figure, the inkjet recording apparatus 10 includes a printing unit 12 having a plurality of inkjet heads (hereinafter also simply referred to as “heads”) 12K, 12C, 12M, and 12Y provided for each ink color. , An ink storage / loading unit 14 for storing ink to be supplied to each of the heads 12K, 12C, 12M, and 12Y, a paper feeding unit 18 for supplying the recording paper 16, and a decurling processing unit for removing the curl of the recording paper 16 20, a suction belt conveyance unit 22 that is disposed opposite to the nozzle surface (ink ejection surface) of the printing unit 12 and conveys the recording paper 16 while maintaining the flatness of the recording paper 16, and printing by the printing unit 12 A print detection unit 24 that reads the result, and a paper discharge unit 26 that discharges printed recording paper (printed matter) to the outside.

  In FIG. 7, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 28 is provided as shown in FIG. 7, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is arranged on the print surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  After the decurling process, the cut recording paper 16 is sent to the suction belt conveyance unit 22. The suction belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least a portion facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 is flat. It is configured to make.

  The belt 33 has a width that is greater than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 7, a suction chamber 34 is provided at a position facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. Then, the suction chamber 34 is sucked by the fan 35 to be a negative pressure, whereby the recording paper 16 on the belt 33 is sucked and held.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 is driven in the clockwise direction in FIG. The recording paper 16 is conveyed from left to right in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blowing method of spraying clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Although a mode using a roller / nip transport mechanism instead of the suction belt transport unit 22 is also conceivable, when the print area is transported by a roller / nip, the roller comes into contact with the print surface of the paper immediately after printing, so that the image blurs. There is a problem that it is easy. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing region is preferable.

  A heating fan 40 is provided on the upstream side of the printing unit 12 on the paper conveyance path formed by the suction belt conveyance unit 22. The heating fan 40 heats the recording paper 16 by blowing heated air onto the recording paper 16 before printing. Heating the recording paper 16 immediately before printing makes it easier for the ink to dry after landing.

  The printing unit 12 is a so-called full-line type head in which line-type heads having a length corresponding to the maximum paper width are arranged in a direction (main scanning direction) orthogonal to the paper transport direction (sub-scanning direction). Each of the heads 12K, 12C, 12M, and 12Y constituting the printing unit 12 has a plurality of ink discharge ports (nozzles) arranged over a length exceeding at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. A line type head (see FIG. 8).

  A head corresponding to each color ink in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side (left side in FIG. 7) along the conveyance direction (paper conveyance direction) of the recording paper 16. 12K, 12C, 12M, and 12Y are arranged. A color image can be formed on the recording paper 16 by ejecting the color ink from each of the heads 12K, 12C, 12M, and 12Y while conveying the recording paper 16.

  Thus, according to the printing unit 12 in which the full line head that covers the entire width of the paper is provided for each ink color, the recording paper 16 and the printing unit 12 are relatively moved in the paper transport direction (sub-scanning direction). It is possible to record an image on the entire surface of the recording paper 16 by performing this operation only once (that is, by one sub-scan). Thereby, high-speed printing is possible and productivity can be improved as compared with a shuttle type head in which the head reciprocates in a direction (main scanning direction) orthogonal to the paper transport direction.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a head for ejecting light-colored ink such as light cyan and light magenta.

  As shown in FIG. 7, the ink storage / loading unit 14 has tanks for storing inks of colors corresponding to the heads 12K, 12C, 12M, and 12Y, and each tank is connected via a pipe line (not shown). The heads 12K, 12C, 12M, and 12Y communicate with each other. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. is doing.

  The print detection unit 24 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the print unit 12, and means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor. Function as.

  The print detection unit 24 of this example is composed of a line sensor having a light receiving element array that is wider than at least the ink ejection width (image recording width) of the heads 12K, 12C, 12M, and 12Y. The line sensor includes an R sensor row in which photoelectric conversion elements (pixels) provided with red (R) color filters are arranged in a line, a G sensor row provided with green (G) color filters, The color separation line CCD sensor includes a B sensor array provided with a blue (B) color filter. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 24 reads the test patterns printed by the heads 12K, 12C, 12M, and 12Y for each color, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  A post-drying unit 42 is provided following the print detection unit 24. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined uneven surface shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 26. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with sorting means (not shown) for switching the paper discharge path in order to select the print product of the main image and the print product of the test print and send them to the discharge units 26A and 26B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 48 is the same as that of the first cutter 28 described above, and includes a fixed blade 48A and a round blade 48B.

  Although not shown, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

[Head structure]
Next, the structure of the heads 12K, 12C, 12M, and 12Y will be described. Since the structures of the heads 12K, 12C, 12M, and 12Y are common, the head is represented by the reference numeral 50 in the following.

  FIG. 9A is a plan perspective view showing a structural example of the head 50, and FIG. 9B is an enlarged view of a part thereof. FIG. 9C is a perspective plan view showing another structural example of the head 50. FIG. 10 is a cross-sectional view (a cross-sectional view taken along line XX in FIGS. 9A and 9B) showing a three-dimensional configuration of the ink chamber unit.

  In order to increase the dot pitch formed on the recording paper surface, it is necessary to increase the nozzle pitch in the head 50. As shown in FIGS. 9A and 9B, the head 50 of this example includes a plurality of ink chamber units 53 including nozzles 51 that are ink droplet ejection holes and pressure chambers 52 corresponding to the nozzles 51. Nozzles that are arranged in a staggered matrix (two-dimensionally), and are thus projected in a row along the head longitudinal direction (main scanning direction perpendicular to the paper transport direction). High density of the interval (projection nozzle pitch) is achieved.

  The form in which one or more nozzle rows are configured over a length corresponding to the entire width of the recording paper 16 in a direction substantially orthogonal to the paper transport direction is not limited to this example. For example, instead of the configuration of FIG. 9A, as shown in FIG. 9C, short head blocks (head chips) 50 ′ in which a plurality of nozzles 51 are two-dimensionally arranged are arranged in a staggered manner. By connecting them together, a line head having a nozzle row having a length corresponding to the entire width of the recording paper 16 may be configured. Although not shown, a line head may be configured by arranging short heads in a line.

  The pressure chamber 52 provided corresponding to each nozzle 51 has a substantially square planar shape, and the nozzle 51 and the supply port 54 are provided at both corners on the diagonal line. Each pressure chamber 52 communicates with a common flow channel 55 through a supply port 54. The common channel 55 communicates with an ink supply tank (not shown in FIG. 10, indicated by reference numeral 60 in FIG. 11) as an ink supply source, and the ink supplied from the ink supply tank passes through the common channel 55. Distribution is supplied to each pressure chamber 52.

  A piezoelectric element 58 having an individual electrode 57 is joined to a diaphragm 56 that constitutes the top surface of the pressure chamber 52 and also serves as a common electrode. By applying a driving voltage to the individual electrode 57, the piezoelectric element 58 is Deformation causes ink to be ejected from the nozzle 51. When ink is ejected, new ink is supplied from the common channel 55 to the pressure chamber 52 through the supply port 54.

  In this example, the piezoelectric element 58 is applied as a means for generating ink ejection force ejected from the nozzles 51 provided in the head 50. However, a heater is provided in the pressure chamber 52, and the pressure of film boiling caused by heating of the heater is used. It is also possible to apply a thermal method that ejects ink.

  As shown in FIG. 9B, the ink chamber units 53 having such a structure are arranged in a fixed manner along a row direction along the main scanning direction and an oblique column direction having a constant angle θ that is not orthogonal to the main scanning direction. By arranging a large number of patterns in a lattice pattern, the high-density nozzle head of this example is realized.

  That is, with a structure in which a plurality of ink chamber units 53 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction, the pitch P of the nozzles projected so as to be aligned in the main scanning direction is d × cos θ. Thus, in the main scanning direction, each nozzle 51 can be handled equivalently as a linear arrangement with a constant pitch P. With such a configuration, it is possible to realize a high-density nozzle configuration in which 2400 nozzle rows are projected per inch (2400 nozzles / inch) so as to be aligned in the main scanning direction.

  As shown in FIG. 10, the head 50 in the present embodiment is a head having a laminated structure in which a plurality of thin plate laminated members 200A to 200F are laminated. The first thin plate laminated member 200A is a nozzle plate in which a plurality of nozzles 51 are formed. The second to fifth thin-plate laminated members 200 </ b> B to 200 </ b> E are flow path forming substrates on which grooves and holes that become ink flow paths such as the pressure chambers 52 and the common flow path 55 are formed. The sixth thin plate laminated member 200 </ b> F is a diaphragm 56 that forms the top surface of the pressure chamber 52. These thin plate laminated members 200A to 200F are joined to each other adjacent thin plate laminated member by the above-described substrate joining method, and are joined with high dimensional accuracy without peeling of the joint portion. Therefore, this head 50 is very excellent in durability.

  In the implementation of the present invention, the nozzle arrangement structure is not limited to the illustrated example, and various nozzle arrangement structures such as an arrangement structure having one nozzle row in the sub-scanning direction can be applied.

  Further, the application range of the present invention is not limited to the printing method using the line-type head, and a short head that is less than the length of the recording paper 16 in the width direction (main scanning direction) is scanned in the width direction of the recording paper 16. Printing in the width direction is performed, and when printing in one width direction is completed, the recording paper 16 is moved by a predetermined amount in a direction perpendicular to the width direction (sub-scanning direction), and the recording paper 16 in the next printing area is moved. A serial method in which printing is performed in the width direction and printing is performed over the entire printing area of the recording paper 16 by repeating this operation may be applied.

[Configuration of ink supply system]
FIG. 11 is a schematic diagram illustrating a configuration of an ink supply system in the inkjet recording apparatus 10. In the figure, an ink tank 60 is a base tank that supplies ink to a head 50, and is installed in the ink storage / loading unit 14 described with reference to FIG. In the form of the ink tank 60, there are a system that replenishes ink from a replenishing port (not shown) and a cartridge system that replaces the entire tank when the remaining amount of ink is low. A cartridge system is suitable for changing the ink type according to the intended use. In this case, it is preferable that the ink type information is identified by a barcode or the like, and ejection control is performed according to the ink type. The ink tank 60 in FIG. 11 is equivalent to the ink storage / loading unit 14 in FIG. 7 described above.

  A filter 62 is provided between the ink tank 60 and the head 50 in order to remove foreign matters and bubbles. The filter mesh size is preferably equal to or smaller than the nozzle diameter (generally about 20 μm). Although not shown in FIG. 11, a configuration in which a sub tank is provided in the vicinity of the head 50 or integrally with the head 50 is also preferable. The sub-tank has a function of improving a damper effect and refill that prevents fluctuations in the internal pressure of the head 50.

  Further, the inkjet recording apparatus 10 is provided with a cap 64 as a means for preventing ink viscosity increase and drying near the nozzles, and a cleaning blade 66 as a means for cleaning the ink discharge surface 50a of the head 50. Yes. The maintenance unit including the cap 64 and the cleaning blade 66 can be moved relative to the head 50 by a moving mechanism (not shown), and is moved from a predetermined retracted position to a maintenance position below the head 50 as necessary.

  The cap 64 is displaced up and down relatively with respect to the head 50 by an elevator mechanism (not shown). The cap 64 is raised to a predetermined raised position when the power is turned off or during printing standby, and is brought into close contact with the head 50, thereby covering the ink ejection surface 50 a with the cap 64.

  The cleaning blade 66 is made of an elastic member such as rubber, and can slide on the ink discharge surface 50a of the head 50 by a blade moving mechanism (not shown). When ink droplets or foreign matter adheres to the ink ejection surface 50a, the ink droplets or the like are wiped off by performing a so-called wiping operation in which the cleaning blade 66 slides on the ink ejection surface 50a.

  During printing or standby, when a specific nozzle is used less frequently and the ink viscosity in the vicinity of the nozzle increases, preliminary discharge is performed toward the cap 64 to discharge the deteriorated ink.

  Further, when bubbles are mixed in the ink in the head 50 (in the pressure chamber 52), the cap 64 is applied to the head 50, and the ink in the head 50 (ink containing the bubbles) is removed by suction with the suction pump 67, The sucked and removed ink is sent to the collection tank 68. In this suction operation, the deteriorated ink that has increased in viscosity (solidified) is sucked out when the ink is initially loaded into the head 50 or when the ink is used after being stopped for a long time.

  If the head 50 is not ejected for a certain period of time, the ink solvent near the nozzles evaporates and the viscosity of the ink near the nozzles increases, and the ejection driving actuator (piezoelectric element 58) operates. Ink is no longer ejected from the nozzle 51. Therefore, before this state is reached (within the viscosity range in which ink can be ejected by the operation of the piezoelectric element 58), the piezoelectric element 58 is operated toward the ink receiver, and the ink in the vicinity of the nozzle whose viscosity has increased is removed. “Preliminary discharge” is performed. Further, after the dirt on the ink discharge surface 50a is cleaned by a wiper such as a cleaning blade 66 provided as a cleaning means for the ink discharge surface 50a, foreign matter is mixed into the nozzle by this wiper rubbing operation (wiping operation). In order to prevent this, preliminary discharge is performed. Note that the preliminary discharge may be referred to as “empty discharge”, “purge”, “spitting”, or the like.

  Further, if bubbles are mixed into the nozzle 51 or the pressure chamber 52 or if the ink viscosity in the vicinity of the nozzle exceeds a certain level, ink cannot be ejected by the preliminary ejection, and the suction operation described below is performed.

  That is, when bubbles are mixed in the ink in the nozzle 51 or the pressure chamber 52, or when the ink viscosity in the vicinity of the nozzle rises to a certain level or more, the ink cannot be ejected from the nozzle even if the piezoelectric element 58 is operated. . In such a case, the cap 64 is brought into contact with the ink ejection surface 50a of the head 50 as a suction means for sucking the ink in the pressure chamber 52 with a pump or the like, and the operation of sucking ink mixed with bubbles or thickened ink is performed. Done.

[Control system configuration]
FIG. 12 is a principal block diagram showing a control system of the inkjet recording apparatus 10. The inkjet recording apparatus 10 includes a communication interface 70, a system controller 72, a memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 86. As the communication interface 70, a serial interface such as USB (Universal Serial Bus), IEEE 1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted.

  The image data sent from the host computer 86 is taken into the inkjet recording apparatus 10 via the communication interface 70 and temporarily stored in the memory 74. The memory 74 is a storage unit that temporarily stores an image input via the communication interface 70, and data is read and written through the system controller 72. The memory 74 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 72 is a control unit that controls the communication interface 70, the memory 74, the motor driver 76, the heater driver 78, and the like. The system controller 72 includes a central processing unit (CPU) and its peripheral circuits, and performs communication control with the host computer 86, read / write control of the memory 74, and the like, and controls the motor 88 and heater 89 of the transport system. A control signal to be controlled is generated.

  The memory 74 stores programs executed by the CPU of the system controller 72 and various data necessary for control. Note that the memory 74 may be a non-rewritable storage means or a rewritable storage means such as an EEPROM. The memory 74 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 76 is a driver (drive circuit) that drives the motor 88 in accordance with an instruction from the system controller 72. The heater driver 78 is a driver that drives the heaters 89 of the post-drying unit 42 and other units in accordance with instructions from the system controller 72.

  The print control unit 80 has a signal processing function for performing various processing and correction processing for generating a print control signal from image data in the memory 74 in accordance with the control of the system controller 72, and the generated print control. A control unit that supplies a signal (dot data) to the head driver 84. Necessary signal processing is performed in the print controller 80, and the ejection amount and ejection timing of the ink droplets of the head 50 are controlled via the head driver 84 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 80 includes an image buffer memory 82, and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print control unit 80. In FIG. 12, the image buffer memory 82 is shown in a mode associated with the print control unit 80, but it can also be used as the memory 74. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with one processor.

  The head driver 84 generates a drive signal for driving the piezoelectric elements 58 (see FIG. 10) of the heads 50 of each color based on the dot data given from the print control unit 80, and the generated drive signal is output to the piezoelectric elements 58. Supply. The head driver 84 may include a feedback control system for keeping the driving condition of the head 50 constant.

  As described with reference to FIG. 7, the print detection unit 24 is a block including a line sensor, reads an image printed on the recording paper 16, performs necessary signal processing, and the like to perform a print status (whether ejection is performed, droplet ejection And the detection result is provided to the print control unit 80.

  The print controller 80 performs various corrections on the head 50 based on information obtained from the print detector 24 as necessary.

  Various control programs are stored in the program storage unit 90, and the control programs are read and executed in accordance with instructions from the system controller 72. The program storage unit 290 may use a semiconductor memory such as a ROM or EEPROM, or may use a magnetic disk or the like. An external interface may be provided and a memory card or PC card may be used. Of course, you may provide several recording media among these recording media. The program storage unit 90 may also be used as a recording means (not shown) for operating parameters.

  As described above, the substrate bonding method, the substrate bonded body, the ink jet head, and the image forming apparatus of the present invention have been described in detail, but the present invention is not limited to the above examples, and is within the scope not departing from the gist of the present invention. Of course, various improvements and modifications may be made.

Process drawing showing an example of a substrate bonding method according to the present invention The figure which showed an example of application by a dispenser Diagram showing an example of the transfer method The figure which showed the board | substrate joining method when the 1st board | substrate curved in reverse direction The figure which showed the curvature state of the 1st board | substrate with which the hole part (through-hole) was formed The figure which showed the board | substrate joining method in the case of using three types of adhesives from which flexibility differs Overall configuration diagram showing outline of inkjet recording apparatus FIG. 7 is a plan view of the main part around the printing unit of the ink jet recording apparatus shown in FIG. Plane perspective view showing structural example of head Cross-sectional view along line XX in FIG. Schematic diagram showing the configuration of an ink supply system in an inkjet recording apparatus Main block diagram showing the control system of the ink jet recording apparatus

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device 50 ... Head, 51 ... Nozzle, 52 ... Pressure chamber, 54 ... Ink supply port, 55 ... Common liquid chamber, 58 ... Piezoelectric element, 100 ... First substrate, 100A ... Groove, 100B ... Hole Part, 102 ... second substrate, 150 ... substrate assembly, S1 ... first adhesive, S2 ... second adhesive

Claims (11)

A substrate bonding method for bonding a first substrate and a second substrate using a plurality of adhesives having different flexibility,
A processing step of forming a groove or a hole in at least one of the first and second substrates;
An application position determining step for determining an application position of the plurality of adhesives with respect to a bonding surface of the first or second substrate according to a warped state of the substrate in which the groove or the hole is formed;
Applying the plurality of adhesives to the bonding surface of the first or second substrate according to the application position of the plurality of adhesives determined according to the warping state of the substrate in which the groove or hole is formed An application process to
Joining the first and second substrates via the plurality of adhesives, and curing the plurality of adhesives;
A substrate bonding method comprising: The substrate bonding method according to claim 1,
A substrate bonding method comprising a surface treatment step of performing a surface treatment on a bonding surface of the first and second substrates before the coating step is performed. In the board | substrate bonding method of Claim 1 or 2,
The application position determining step includes a step of detecting a warpage state of the substrate on which the groove or the hole is formed by determining a distance between the substrates of the first and second substrates. Method. The substrate bonding method according to claim 3,
Among the plurality of adhesives, when a flexible adhesive having a high flexibility is used as a first adhesive and a low flexible adhesive is used as a second adhesive,
In the application position determining step, a portion where the distance between the first and second substrates is larger than a reference value is set as the application position of the first adhesive, and a portion smaller than the reference value is set as the second adhesive. A substrate bonding method characterized in that the substrate is applied. In the board | substrate joining method of any one of Claims 1 thru | or 4,
All of the plurality of adhesives are epoxy adhesives. The substrate bonding method according to claim 5,
The substrate bonding method, wherein the plurality of adhesives are made of the same epoxy resin, and are adhesives having different amounts of flexibility or different materials. A substrate joined body composed of first and second substrates joined by a plurality of adhesives having different flexibility,
Grooves or holes are formed in at least one of the first and second substrates,
Among the plurality of adhesives, when a flexible adhesive having a high flexibility is used as a first adhesive and a low flexible adhesive is used as a second adhesive,
The portion where the stress applied to the adhesive at the joint between the first and second substrates is greater than the reference value is joined with the first adhesive, and the portion less than the reference value is joined with the second adhesive. A substrate joined body characterized by the above. The substrate bonded body according to claim 7,
The plurality of adhesives are all epoxy adhesives. The substrate bonded body according to claim 8,
The plurality of adhesives are made of the same epoxy resin, and are adhesives having different amounts of flexibility or different materials.   An ink jet head comprising the substrate assembly according to claim 7.   An image forming apparatus comprising the inkjet head according to claim 10.

Images