Liquid dispensing head and method for manufacturing a liquid dispensing head

Abstract

If the liquid dispensing head is dropped with the circuit board facing downwards, there is a problem in that the tip of the crimped part that secures the circuit board breaks, causing the circuit board to detach from the housing component. [Solution] A liquid dispensing head comprising a housing member having a liquid dispensing module for dispensing liquid and a flow path for supplying liquid to the liquid dispensing module, and a wiring board having a contact pad on its first surface for electrical connection with a liquid dispensing device, wherein the liquid dispensing head comprises a first fixing portion to which the wiring board and the housing member are mechanically fixed, and a second fixing portion between a second surface of the wiring board located opposite to the first surface and an adhesive surface provided on the housing member, and the second fixing portion is fixed with an adhesive.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a method for manufacturing the liquid ejection head.

Background Art

[0002] The liquid ejection head has a wiring board for receiving an electrical signal from a liquid ejection device. In the liquid ejection head, the wiring board is fixed to the housing member only by thermal caulking. Further, the wiring board is fixed at four points at substantially the four corners of the housing member. Some liquid ejection heads fix the wiring board to the housing member with screws, but from the viewpoint of cost in terms of parts management, process management, etc., fixing methods such as thermal caulking and snap fit are desirable.

[0003] The wiring board relays a drive signal and drive power from the liquid ejection device to the liquid ejection head. In the wiring board, in order to achieve an electrical connection by bringing the terminals (pins) of the liquid ejection device into contact with the terminals (pads) of the liquid ejection head, the respective terminals are arranged closely, and it is difficult to perform wiring in a single layer. For this reason, a wiring board having a two-layer structure composed of both sides combining a first layer for a drive signal and a second layer for drive power is often used. The wiring board using a double-sided wiring board in this case is often small and light, and fixing to the housing member with only thermal caulking was sufficient. Also, even when pressure is applied from the back surface of the wiring board, the reliability of the caulked portion could be ensured by minimizing deformation of the wiring board.

[0004] For example, the head cartridge described in Patent Document 1 has a structure in which an electrical connection is made with an ink tank on the back surface of a wiring board fixed to a housing member. Patent Document 1 shows a structure for suppressing the swelling of the wiring board to the surface side by the pressing force from the ink tank in a head cartridge having such a structure. This structure minimizes the swelling of the wiring board to the surface side by arranging electrical connection portions on a straight line connecting the caulked portions at both ends or within the caulked regions at the four corners.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-358912 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the inkjet printer field, circuit boards have become thicker and larger in recent years. As a result, these circuit boards have become heavier. In liquid ejection heads with such circuit boards, there was a problem that if the circuit board fell in a downward position, the tip of the crimped part that secures the circuit board would break, causing the circuit board to detach. [Means for solving the problem]

[0007] This disclosure relates to a liquid dispensing head comprising at least a housing member and a wiring board, wherein the housing member comprises a liquid dispensing module and a flow path for supplying liquid to the liquid dispensing module, the wiring board comprises a contact pad on a first surface, and the liquid dispensing head comprises a first fixing portion to which the wiring board and the housing member are mechanically fixed, and a second fixing portion between a second surface of the wiring board located opposite to the first surface and an adhesive surface provided on the housing member, the second fixing portion being fixed with an adhesive. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a liquid dispensing head that can suppress cracking of the tip of the crimped portion that secures the wiring board, even if the liquid dispensing head is dropped in a position where the wiring board is facing downwards. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 is a schematic diagram of the liquid dispensing device. [Figure 2] Figure 2 is a perspective view of the liquid dispensing head. [Figure 3] Figure 3 is an exploded perspective view of the liquid dispensing head. [Figure 4] Figure 4 is a schematic diagram showing how the wiring board is fixed to the housing component. [Figure 5] Figure 5 is a schematic diagram showing a cross-section of a wiring board and mounted components. [Figure 6] Figure 6 is a schematic diagram showing the state of the crimped portion when a conventional liquid dispensing head is dropped. [Figure 7] Figure 7 is a perspective view showing the liquid dispensing head of this disclosure before the wiring board is fixed in place. [Figure 8] Figure 8 is a schematic diagram showing the state of the crimped portion when the liquid dispensing head of this disclosure is dropped. [Figure 9] Figure 9 is a flowchart of a method for manufacturing a liquid dispensing head, including the procedure for assembling the wiring board into the housing component. [Figure 10] Figure 10 is a schematic diagram showing the contact surface and adhesive surface of a wiring board. [Figure 11] Figure 11 is a schematic diagram showing variations in the shape of the adhesive surface. [Figure 12] Figure 12 is a graph showing the simulation results of the stress applied to the base of the crimping pin. [Modes for carrying out the invention]

[0010] Embodiments of the liquid dispensing head of this disclosure will be described below with reference to the drawings. The embodiments described below are intended to illustrate examples of this disclosure and are not intended to limit the scope of this disclosure. The dimensions, shapes, number, materials, etc. of the various components in the following embodiments can be modified as appropriate within the scope of this disclosure unless otherwise specified.

[0011] Figure 1 is a schematic diagram of a liquid ejection device 100 that can utilize the liquid ejection head of this disclosure. The liquid ejection device 100 is a serial scan inkjet recording device. This recording device has a liquid ejection head 102 and is of the type that ejects ink from the liquid ejection head 102 to record an image on a recording medium 104. The liquid ejection device 100 is provided with an ink tank and a pump, which are the ink supply sources. The ink stored in the ink tank is supplied to a circulation unit via an ink supply tube by the driving force of the pump. The liquid ejection head 102 is mounted on a carriage 106. The liquid ejection head 102 includes a sub-tank unit 108. The sub-tank unit 108 is connected to the ink tank and is supplied with ink for each ink. Electrical wiring, ink, and air piping necessary for printing are supplied to the carriage 106 by a guide 110. The carriage 106 reciprocates along the guide axis 112 in the main scanning direction of arrow X. The recording medium 104 is transported by transport rollers 114, 116, 118, and 120 in the sub-scanning direction of arrow Y, which intersects (orthogonal in this example) the main scanning direction.

[0012] The liquid ejection head 102 is capable of high-quality full-color printing using multiple color inks. The liquid ejection device 100 has a cap member (not shown) positioned away from the transport path of the recording medium 104. When the liquid ejection device is not performing a recording operation, this cap member moves relative to a position that covers the face surface of the liquid ejection head 102 and performs suction operations to prevent or restore drying of the ejection port and to fill the ink.

[0013] In recent years, in the field of inkjet printers, a circulating liquid ejection device has been demanded to output high-quality printed materials. The liquid ejection head mounted on the circulating liquid ejection device has a liquid supply channel and a liquid recovery channel in the ejection port row. Thereby, the liquid can be circulated through the pressure chamber corresponding to the ejection port. According to such a configuration, during printing, it is possible to suppress the thickening of the liquid near the ejection port and in the channel due to the discharge of bubbles in the channel and the evaporation of moisture from the ejection port. In order to circulate the ink with a scanning type liquid ejection head, the liquid ejection head is equipped with a plurality of sub-tanks having circulation pumps in the circulation unit.

[0014] The sub-tank is respectively connected to the liquid supply channel and the liquid recovery channel provided in the housing member in the liquid ejection head. The signal for driving the circulation pump of the sub-tank is transmitted from the wiring board provided in the liquid ejection head. The wiring board requires an element for driving the pump. In addition to the connector for electrically connecting to a plurality of sub-tanks, electronic components such as resistors, capacitors, inductors, diodes, transistors, control ICs, etc. for constituting the pump drive circuit are mounted. Also, such a wiring board needs to add one more layer to form a drive circuit with respect to the conventional wiring board, preferably add one more layer for the guard of the IJ chip circuit, and is multi-layer wired. Therefore, the wiring board used in the present disclosure has an increased thickness, a larger size, and as a result, a heavier weight. When the liquid ejection head including the heavy wiring board drops in a posture with the wiring board facing downward, the tip portion of the caulked portion fixing the wiring board may crack and the wiring board may come off.

[0015] The liquid ejection head of the present disclosure provides an adhesive portion at an appropriate portion between the housing member of the liquid ejection head and the wiring board in addition to the mechanical fixing of the housing member of the liquid ejection head and the wiring board by a thermal caulking method or a snapshot method. The liquid ejection head of the present disclosure has such a simple configuration that even when the liquid ejection head drops, it becomes a highly reliable liquid ejection head.

[0016] The present disclosure relates to a structure for improving the reliability of a liquid ejection head and a method for manufacturing the liquid ejection head. In particular, the present disclosure provides a highly reliable liquid ejection head with a simple configuration in which an adhesive portion is further provided on the back surface of a wiring board in a method for fixing a housing member and the wiring board in the liquid ejection head.

[0017] In the present disclosure, the surface on which contact pads of the wiring board are present is referred to as the "first surface". In the description of the liquid ejection head of the present disclosure in this specification, the surface on which contact pads of the wiring board are present ("first surface") is referred to as the "contact surface" or "substrate surface (or simply "surface")". In the present disclosure, the surface of the wiring board located on the opposite side of the first surface of the wiring board is referred to as the "second surface". In the description of the liquid ejection head of the present disclosure in this specification, the surface of the wiring board located on the opposite side of the first surface ("second surface") is referred to as the "back surface of the contact surface" or "substrate back surface (or simply "back surface")". Further, in the liquid ejection head of the present disclosure, the wiring board and the housing member are mechanically fixed. The portion that is mechanically fixed is referred to as the "first fixing portion" in this specification. In a preferred embodiment, the first fixing portion is fixed by a thermal caulking method or a snap shot method. In the liquid ejection head of the present disclosure, the wiring board and the housing member are fixed by an adhesive on the second surface of the wiring board and an adhesive surface provided on the housing member. In the present disclosure, the portion fixed by this adhesive is referred to as the "second fixing portion".

[0018] (First Embodiment) A first embodiment of the liquid ejection head of the present disclosure will be described using FIGS. 2 and 3.

[0019] FIG. 2 is a perspective view of the liquid ejection head 102, and FIG. 3 is an exploded perspective view of the liquid ejection head 102.

[0020] As shown in Figures 2 and 3, the liquid dispensing head 102 includes a housing member 202 and a wiring board 204. The wiring board 204 includes contact pads 206. The housing member 202 and the wiring board 204 include crimping portions 208 (four in the example in Figure 2), which secure them to each other. The liquid dispensing head 102 includes a joint member 210, a liquid dispensing module 212, a flexible printed circuit board (FPC) 214, and a head cover 216. The liquid dispensing head may include a circulation unit that includes a circulation pump.

[0021] As shown in Figure 3, the housing member 202 includes a sub-tank unit 108, and the sub-tank unit includes sub-tanks 302, 304, 306, and 308. Although not shown in Figure 3, the liquid discharge head may include a circulation unit equipped with a circulation pump. However, the liquid discharge head of this disclosure may also be configured without a circulation unit equipped with a circulation pump. The housing member 202 is connected to a liquid discharge module 212 and supplies liquid from each of the sub-tanks 302, 304, 306, and 308 to the liquid discharge module 212. The liquid discharge module 212 includes a flexible printed circuit board (FPC) 214. The flexible printed circuit board (FPC) 214 is connected to a wiring board 204. The wiring board 204 includes contact pads 206 for electrical connection with the carriage 106.

[0022] The joint member 210 is a component for connecting the carriage 106 to the liquid and is fixed to the housing member 202 with screws. The head cover 216 is fixed to the top of the housing member 202 and protects each of the subtanks 302, 304, 306 and 308 of the subtank unit 108. Each of the subtanks 302, 304, 306 and 308 is connected to the housing member 202 and the joint member 210 and is electrically connected to the wiring board 204 with cables.

[0023] Referring to Figures 4 to 8, the crimped portion 208 of the liquid discharge head of this disclosure and the connection between the wiring board 204 and the housing member 202 via the crimped portion will be described.

[0024] Figure 4 is a schematic diagram showing how the wiring board 204 is fixed to the housing member 202. In this disclosure, the method of fixing the wiring board 204 and the housing member 202 is not particularly limited as long as it is a method used to fix these members, but a heat crimping method or a snap-fit ​​method is preferred. In the following description, the heat crimping method and the snap-fit ​​method will be used as examples, but this disclosure is not limited to these examples.

[0025] Figure 4(a) shows the heat crimping method, and Figure 4(b) shows the snap-fit ​​method. In the heat crimping method, the protrusion 404 of the housing member is passed through the through hole 402 of the wiring board 204, and the protrusion 404 of the housing member is heated and pressed with a heating tool 406. This melts the tip of the protrusion of the housing member, forming an umbrella-shaped crimped portion 208 at the tip, thereby fixing the wiring board 204 to the housing member 202. In the snap-fit ​​method, the snap-fit ​​408 is inserted into the through hole 402 of the wiring board 204. At this time, the protruding part of the snap-fit ​​deforms inward as it passes through the through hole 402. When the snap-fit ​​408 is inserted all the way in, the tip of the snap-fit ​​408 returns to its original state, and the wiring board 204 and the housing member 202 are fixed together. In the following description of this disclosure, the heat crimping method will be used, but known fixing methods such as the snap-fit ​​method and the press-fit method may also be used. The procedures and conditions for these methods are known to those skilled in the art. Furthermore, the following description assumes that the crimped portions 208 are located approximately at the four corners of the wiring board 204, but the positions of the crimped portions can be appropriately determined by those skilled in the art depending on the required strength.

[0026] Figure 5 is a schematic diagram showing a cross-section of a wiring board 204 and mounted components. Figure 5(a) shows a double-sided wiring board 204(A). Figure 5(b) shows a multilayer wiring board 204(B). Figure 5(c) shows various components mounted on the wiring board 204. More specifically, as shown in Figure 5(a), a double-sided wiring board 204(A) (in this disclosure, a double-sided wiring board is also referred to as wiring board 204(A)) has a substrate surface 204a and a substrate back surface 204b. The wiring board 204(A) includes an insulating layer 502, and metal wiring 504 is patterned on both sides of the wiring board 204(A) via this insulating layer 502. Except for the contact pad 206 portion on the substrate surface 204a side (contact surface) of the wiring board 204(A), both surfaces of the wiring board are covered with solder resist 506.

[0027] As shown in Figure 5(b), the multilayer wiring substrate 204(B) (in this disclosure, the multilayer wiring substrate is also referred to as the wiring substrate 204(B)) has a substrate surface 204a and a substrate back surface 204b. Metal wiring 504 is patterned on both sides of the insulating layer 502 of the wiring substrate 204(B). Both sides of the insulating layer including the metal wiring 504 are covered with prepreg 508. Furthermore, contact pads 206 and metal wiring 504' are patterned on the prepreg. Both surfaces of the wiring substrate 204(B), excluding the portion of the contact pad 206 on the substrate surface 204a side, are covered with solder resist 506.

[0028] Next, Figure 5(c) shows an example of the case where components are mounted on the back surface 204b of the circuit board. The wiring board 204 requires numerous elements to drive the circulation pump included in the circulation unit of the sub-tank unit. For example, as shown in Figure 5(c), the back surface 204b of the circuit board includes connectors for electrically connecting to each sub-tank. In addition, electronic components 510 such as resistors, capacitors, inductors, diodes, transistors, and control ICs are mounted on the back surface 204b of the circuit board to constitute the pump drive circuit.

[0029] Furthermore, it is necessary to add another layer to the wiring board 204(A) to form the drive circuit. Preferably, another layer is also needed to protect the IJ chip circuit. Thus, a multilayer wiring board 204, such as the wiring board 204(B) described above, is included in the liquid dispensing head of this disclosure. For this reason, the wiring board 204 of this disclosure is relatively large for a liquid dispensing head. When fixing such a wiring board 204 to the housing member 202, there are concerns that the crimped portion 208 used to fix the two members may not be strong enough if heat crimping alone is not sufficient. In fact, in the liquid dispensing head of this disclosure, when the crimped portion 208 was fixed alone, a crack occurred at the base of the crimped portion 208 during a drop test.

[0030] Referring to Figure 6, the state of the crimping portion 208 when a liquid dispensing head, in which the wiring board 204 and housing member 202 are fixed only by the crimping portion 208, is dropped will be explained. Figure 6 is a schematic diagram showing this state.

[0031] A model analysis was performed by conducting a drop simulation on the liquid discharge head described above. The model analysis was performed by calculating the deformation of the crimping pin and the stress at the damaged part. The calculations were performed using simulation software (LS-DYNA, manufactured by ANSYS). The simulation results revealed the following: First, when the wiring board 204 is dropped face down (Figure 6(a)), an inertial force acts at the moment it hits the ground. As a result, the wiring board 204, whose central part is not fixed, deforms in a direction that separates the central part from the housing member 202 (Figure 6(b)). It was found that this deformation concentrates stress at the base 602 of the crimping part, causing the tip of the crimping part 208 (the heat-crimped part) to crack. For example, when the drop height was set to 75 cm, the simulation showed that the wiring board 204 deformed by approximately 0.8 mm.

[0032] The cause of the cracks described above is that when the wiring board 204 deformed due to the fall, the crimped portion 208 lacked sufficient strength to withstand the stress applied to it. One possible countermeasure against such cracks is to increase the size of the crimped portion 208 to increase its strength. However, there is a limit to the size of the crimped portion 208 that can be formed by the heat crimping method, and the model analysis in the above simulation showed that this method was not very effective.

[0033] Alternatively, one could consider adding locations for heat crimping. However, since multiple contact pads 206 for electrical connection with the carriage 106 are provided near the center of the wiring board 204, it is difficult to add more fixing points by adding crimping sections 208. Another method is to apply adhesive to the entire back surface of the wiring board 204 (the surface to be bonded to the housing member) and fix the wiring board 204 to the housing member via the adhesive. However, this method requires applying adhesive to the entire back surface of the wiring board 204, and it takes a long time for a large amount of adhesive to harden. For this reason, fixing the wiring board 204 to the housing member via adhesive over the entire back surface is not practical.

[0034] This disclosure provides a reliable liquid dispensing head with a simple configuration by providing an adhesive joint in an appropriate location between the housing member and the wiring board of the liquid dispensing head. The liquid dispensing head with the adhesive joint of this disclosure will be described in more detail below.

[0035] Figure 7 is a perspective view showing the configuration before the wiring board 204 is fixed to the housing member 202. The dashed line in Figure 7 is an enlarged view showing the adhesive portion where the housing member 202 is bonded to the wiring board 204. The housing member 202 is provided with a wiring board receiving surface 702 and an adhesive surface 704 adjacent to each other. In this disclosure, it is preferable that the height of the adhesive surface 704 (the height of the adhesive surface from the housing member 202 toward the wiring board 204) is lower than the height of the wiring board receiving surface 702. The difference in height between the wiring board receiving surface 702 and the adhesive surface 704 is preferably about 0.1 to 1 mm. Adhesive 706 may be applied to the adhesive surface.

[0036] Because of the height difference between the wiring board receiving surface 702 and the adhesive surface 704, a gap is created between the back surface 204b of the wiring board and the adhesive surface 704. The adhesive 706 fills this gap, preventing the wiring board 204 from lifting when the housing member 202 and the wiring board 204 are fixed together.

[0037] The adhesive 706 can be any room-temperature curing adhesive without any particular restrictions. Preferably, a room-temperature curing silicone adhesive can be used. It is preferable that the adhesive 706 be a silicone adhesive. This is because silicone adhesives are easy to handle, the housing member 202 and the wiring board 204 can be removed relatively easily when disassembling the liquid discharge head, and are also preferable from an environmental standpoint. Room-temperature curing adhesives harden after several hours if left as is after application. Therefore, the adhesive surface 704 and a predetermined part of the back surface 204b of the wiring board (the part facing the adhesive surface of the housing member) are fixed by the adhesive after being left for several hours.

[0038] The area on the housing member 202 where the wiring board receiving surface 702 and the adhesive surface 704 are installed (hereinafter also referred to as the adhesive area of ​​the housing member) will be described. The adhesive area of ​​the housing member is an area where the adhesive effect is high when bonding the housing member 202 and the wiring board 204. For example, a rectangular area formed by connecting the protrusions 404 of the crimping pins of the housing member corresponding to the crimping portion is preferred as the adhesive area of ​​the housing member. An adhesive effect can be obtained within this area. However, the adhesive effect decreases as you move away from this rectangular area. The adhesive area of ​​the housing member is more preferably an area corresponding to the area on the wiring board where the contact pad 206 is provided. The most preferred adhesive area of ​​the housing member is the intersection of two diagonals formed by diagonally connecting the protrusions 404 of the crimping pins of the housing member corresponding to the crimping portion. Such an area can effectively suppress deformation of the wiring board 204 when the liquid ejection head falls. Furthermore, such an area can also securely fix the area of ​​the contact pad 206, which is an important part when attaching the liquid ejection head to the printer body. The area of ​​the adhesive region of the housing component is preferably about 15 square millimeters. This area is about 0.5 percent of the area of ​​the wiring board 204.

[0039] Next, the liquid dispensing head with the adhesive surface described above will be further explained with reference to Figure 8. Figure 8 is a schematic diagram showing the state of the crimped portion when the liquid dispensing head of this disclosure is dropped. A model analysis was performed on the liquid dispensing head of this disclosure by drop simulation. The model analysis was performed in the same manner as described earlier for the liquid dispensing head described in Figure 6. That is, the model analysis was performed by calculating the amount of deformation of the crimping pin and the stress at the damaged part. The calculations were performed using simulation software (LS-DYNA ANSYS). The following became clear from the simulation results. First, when the wiring board 204 is dropped face down (Figure 8(a)), an inertial force acts at the moment it hits the ground. In the case of the liquid dispensing head of this disclosure, the wiring board 204 is fixed near the center with adhesive 706, so the wiring board 204 hardly deforms (Figure 8(b)). In this way, the liquid dispensing head of this disclosure can suppress the concentration of stress at the base 602 of the crimped portion. The simulation results showed that cracking at the tip of the crimped portion 208 (the heat-crimped portion) could be suppressed. For example, when the drop height was set to 75 cm, the simulation showed that the deformation of the wiring board 204 was 0.1 mm or less.

[0040] Next, with reference to Figure 9, a method for manufacturing the liquid dispensing head of the present disclosure will be described. The liquid dispensing head of the present disclosure has the structure described above. In particular, in the liquid dispensing head of the present disclosure, the wiring board 204 is mechanically fixed to the housing member 202 at the crimping portion 208 (first fixing portion). The back surface 204b (second surface) of the wiring board 204, which is located opposite to the surface on which the contact pads of the wiring board 204 are provided (first surface), is fixed with adhesive to the adhesive surface 704 (second fixing portion) provided on the housing member.

[0041] First, prepare the components of the liquid dispensing head of this disclosure, particularly the housing member 202 and the wiring board 204 (S1 in Figure 9). The components of the liquid dispensing head of this disclosure can be obtained by known procedures. In particular, as shown in Figure 7, the housing member has a wiring board receiving surface 702 and an adhesive surface 704 near the center of the housing member. The housing member should be manufactured so that such structural parts are formed. The manufacturing method can be one known to those skilled in the art.

[0042] Next, adhesive 706 is applied to the bonding surface 704 of the housing member (S2 in Figure 9). The adhesive 706 can be applied directly to the bonding surface 704. Alternatively, the adhesive 706 can be applied to the back surface 204b of the wiring board so that it aligns with the bonding surface 704 when the wiring board 204 is fixed to the housing member 202. The adhesive 706 can be applied using a dispenser or the like.

[0043] Next, the flexible printed circuit board (FPC) 214 provided in the liquid discharge module 212 is bent 90° in the bending direction of the arrow shown in Figure 7 (S3 in Figure 9). Then, the through holes 402 at approximately the four corners of the wiring board 204 are fitted into the protrusions 404 of the four crimping pins on the housing member 202 to position it (S4 in Figure 9). Next, the tips of the protrusions 404 of the crimping pins are melted with heat to mechanically fix the wiring board 204 to the housing member. The adhesive 706 is a room-temperature curing type and hardens after a few hours. In this way, the back surface 204b of the wiring board and the adhesive surface 704 are fixed with the adhesive (S5 in Figure 9). When the back surface 204b of the wiring board comes into contact with the wiring board receiving surface 702, a gap exists between the back surface 204b of the wiring board and the adhesive surface 704. Therefore, the adhesive 706 fills this gap, and the wiring board 204 does not float.

[0044] The connectors mounted on the wiring board 204 are connected by cables to each of the sub-tanks 302, 304, 306, and 308, respectively (see Figure 7). In this way, the liquid dispensing head of the present disclosure is manufactured.

[0045] (Second Embodiment) The second embodiment is an example in which the adhesive for the bonding surface in the first embodiment is applied to the back surface of the wiring board. In the description of the first embodiment, an example was given in which the adhesive was applied to the bonding surface of the housing member, but the adhesive may also be applied to the wiring board side. In this case, when the wiring board 204 is fixed to the housing member 202, the adhesive 706 is applied to the back surface 204b of the wiring board so that the position where the adhesive was applied on the wiring board 204 aligns with the position of the bonding surface 704.

[0046] Figure 10 is a schematic diagram showing the contact surface and back surface of the wiring board 204. Using this figure, the adhesive area on the back surface 204b of the wiring board will be explained. As shown in Figure 10(a), in this disclosure, a contact pad 206 is provided on the surface 204a of the wiring board. In this embodiment, the area 1002 on the back surface 204b of the wiring board, corresponding to the contact pad 206, is an area where the adhesive effect is high. In the second embodiment, the area 1002 on the back surface of the contact pad is a preferred area for adhesive application. Among these, the intersection of two diagonals connecting the through holes of the wiring board diagonally, corresponding to the crimping portion, is the most preferred position for adhesive application. Such an area can effectively suppress deformation of the wiring board 204 when it is dropped. Furthermore, such an area can reliably fix the area of ​​the contact pad 206, which is an important part when attaching the liquid ejection head to the printer body.

[0047] Furthermore, the region 1004 shown in Figure 10(b) is a rectangular area formed by connecting the through holes corresponding to the crimping portion, and sufficient adhesive effect can be obtained within this region as well. However, the adhesive effect decreases as you move outward from the center of this region 1004. The area to which the wiring board 204 is bonded is approximately 15 square millimeters, and this area is sufficient to securely fix the housing member and the wiring board. The ratio of the bonded surface to the wiring board 204 is preferably about 0.5 percent.

[0048] The liquid dispensing head of the second embodiment is the same in structure and manufacturing method as the first embodiment, except that the adhesive is applied to the wiring board 204.

[0049] The adhesive 706 may be applied in a combination of application methods as in the first and second embodiments, or it may be applied to the above-mentioned positions on the back surface of the wiring board, or to the adhesive surface 704 of the housing member described in the first embodiment.

[0050] (Third embodiment) The third embodiment illustrates the shape of the adhesive surface 704.

[0051] Figure 11 is a schematic diagram showing an example of the shape of the adhesive surface 704. The shape of the adhesive surface 704 shown in Figure 11 is an example of a shape that can be implemented in this disclosure. The shape shown in Figure 11 is just one example, and the shape of the adhesive surface 704 that can be used in this disclosure is not particularly limited as long as it can bond the housing member 202 and the wiring board 204. A preferred shape of the adhesive surface is shown in Figure 11(a). Figures 11(b) and 11(c) showing the shapes of the adhesive surface are modifications of the adhesive surface 1102. All of these shapes take into consideration moldability and cracking when dropped, and can provide an effective bonding area in a space-saving manner. Furthermore, these shapes can be expected to have an anchoring effect as the adhesive flows into the corners of the ribs. In this disclosure, the surface of these adhesive surfaces can be further textured. Textured processing can make the surface of the adhesive surface rougher, which can provide an even greater anchoring effect.

[0052] In this disclosure, the number of branches and × shapes in the above shape is not particularly limited, but is preferably 3 to 10, and more preferably 3 to 5.

[0053] As described above, the liquid dispensing head of this disclosure can securely fix relatively large wiring boards to a housing member by fixing the central part of the back surface of the wiring board to the housing member with adhesive. The liquid dispensing head of this disclosure can suppress deformation of the wiring board even if it is dropped with the wiring board face down, and almost no stress is applied to the crimped part. Therefore, damage to the crimped part can be suppressed, and a liquid dispensing head with high reliability in the event of a fall can be provided using an inexpensive and simple method of fixing with heat crimping and adhesive. [Examples]

[0054] (Example 1) The effectiveness of the liquid dispensing head of this disclosure was evaluated by conducting a drop test. In this embodiment, the liquid dispensing head is formed by bonding the adhesive surface 704 of a housing member, whose surface has been roughened with a file, to a wiring board with adhesive 706. A room-temperature curing silicone-based adhesive was used. A drop test was conducted on this liquid dispensing head. The conditions for the drop test were to drop the liquid dispensing head of this disclosure from a height of 150 cm onto concrete at a temperature of 5°C, with the side containing the wiring board facing downwards, and evaluate whether the crimped head of the crimped part broke and scattered. The drop test was repeated twice, and in both cases, the base of the crimped part did not break.

[0055] (Comparative Example 1) A drop test was conducted on a liquid dispensing head in which the housing component and the wiring board were bonded together using only heat crimping. The drop test was the same as in Example 1, except that no adhesive was used and the drop height was set to 75 cm. As a result of the drop test, the crimped head of the crimped part cracked and scattered on the second drop.

[0056] (Example 2) This embodiment shows the results of a simulation evaluation of the liquid discharge head described herein and a liquid discharge head in which the housing member and the wiring board are fixed only by heat crimping.

[0057] A model analysis was performed by conducting a drop simulation on a liquid discharge head in which the housing member 202 and the wiring board 204 were fixed only by the crimped portion 208. Figure 12 is a graph showing the simulation results of the stress applied to the base of the crimped portion 208 of this liquid discharge head (PIN-REF in Figure 12). The simulation was performed by calculating the deformation amount of the crimping pin and the stress at the point of failure. The calculations were performed using simulation software (LS-DYNA, manufactured by ANSYS). As shown in Figure 12, the stress applied to the base of the crimped portion 208 increases with increasing drop height. The stress applied to the base of the crimped portion 208 at a height of 75 cm was 267 [MPa]. At a height of 60 cm, the stress applied to the base of the crimped portion 208 was 230 [MPa]. Based on these results and the test results of the above embodiment, it was determined that the threshold for when the crimped portion 208 breaks is approximately 240 [MPa] to 270 [MPa]. In contrast, when the back surface 204b of the wiring board was fixed with adhesive, the simulation result of the stress applied to the base of the crimped portion 208 was 129 [MPa] (position of the adhesive on the back surface of the board (black square) in Figure 12). The effect was also confirmed by the simulation values ​​for the liquid discharge head of this disclosure in which the housing member 202 and the wiring board 204 are fixed with heat crimping and adhesive.

[0058] As described above, in actual drop tests and simulation evaluations, the liquid discharge head of this disclosure was found to be able to suppress deformation of the wiring board and suppress damage to the crimped portion, even when dropped with the wiring board face downwards. [Explanation of symbols]

[0059] 102 Liquid dispensing head 202 Enclosure components 204 Wiring board 206 Contact Pads 208 Crimping section 212 Liquid Dispensing Module 704 Adhesive surface

[0060] <<Other Embodiments>> The disclosures described in each of the above embodiments include configurations represented by the following example of a liquid dispensing head.

[0061] <Configuration 1> A housing member comprising a liquid dispensing module for dispensing liquid, and a flow path for supplying liquid to the liquid dispensing module, A wiring board having contact pads on its first surface for electrical connection to a liquid dispensing device, A liquid dispensing head having, A liquid dispensing head having a first fixing portion to which the wiring board and the housing member are mechanically fixed, and a second fixing portion between a second surface of the wiring board located opposite to the first surface and an adhesive surface provided on the housing member, the second fixing portion being fixed with an adhesive.

[0062] <Configuration 2> The first fixing part is the liquid dispensing head described in configuration 1, which is located at the four corners of the wiring board.

[0063] <Structure 3> The liquid dispensing head according to configuration 2, wherein the adhesive surface is provided within the area surrounded by the first fixing parts located at the four corners of the wiring board.

[0064] <Structure 4> The liquid dispensing head according to configuration 2, wherein the adhesive surface is located at a position that includes the intersection of lines connecting the four corners of the first fixing portion arranged diagonally to the four corners of the wiring board.

[0065] <Composition 5> The liquid dispensing head according to any one of configurations 1 to 4, wherein the mechanical fixing of the first fixed part is by heat crimping.

[0066] <Composition 6> The liquid dispensing head according to any one of configurations 1 to 5, wherein the adhesive surface has a height lower than the height of the wiring board receiving surface provided on the wiring board.

[0067] <Composition 7> The aforementioned adhesive surface is textured, and the liquid dispensing head is as described in any one of configurations 1 to 6.

[0068] <Structure 8> A liquid dispensing head according to any one of configurations 1 to 7, having a circulation unit for circulating liquid with the liquid dispensing module.

[0069] <Composition 9> The liquid discharge head according to configuration 8, comprising a pump in the circulation unit.

[0070] <Composition 10> A housing member comprising a liquid dispensing module for dispensing liquid, and a flow path for supplying liquid to the liquid dispensing module, A wiring board having contact pads on its first surface for electrical connection to a liquid dispensing device, A method for manufacturing a liquid dispensing head having, The process involves mechanically fixing the wiring board and the housing member at the first fixing part, A method for manufacturing a liquid dispensing head, comprising the step of fixing the wiring board with an adhesive at a second fixing portion between a second surface located opposite to the first surface and an adhesive surface provided on the housing member.

[0071] <Composition 11> A method for manufacturing a liquid dispensing head according to configuration 10, wherein the adhesive is applied to an adhesive surface provided on the housing member, and then the wiring board and the housing member are mechanically fixed at a plurality of first fixing parts provided at their four corners, and the wiring board and the housing member are fixed with the adhesive at the second fixing part.

[0072] <Composition 12> A method for manufacturing a liquid dispensing head according to configuration 10, wherein the adhesive is applied to the second surface of the wiring board so as to align with the adhesive surface provided on the housing member, and then the wiring board and the housing member are mechanically fixed together by a plurality of first fixing parts provided at their four corners, and the wiring board and the housing member are fixed together by the adhesive at the second fixing parts.

[0073] <Composition 13> The adhesive is a room-temperature curing type. A method for manufacturing a liquid dispensing head according to any one of the components 10 to 12.

Claims

1. A housing member comprising a liquid dispensing module for dispensing liquid, and a flow path for supplying liquid to the liquid dispensing module, A wiring board having contact pads on its first surface for electrical connection to a liquid dispensing device, A liquid dispensing head having, A liquid dispensing head having a first fixing portion to which the wiring board and the housing member are mechanically fixed, and a second fixing portion between a second surface of the wiring board located opposite to the first surface and an adhesive surface provided on the housing member, the second fixing portion being fixed with an adhesive.

2. The liquid dispensing head according to claim 1, wherein the first fixing portion is arranged at the four corners of the wiring board.

3. The liquid dispensing head according to claim 2, wherein the adhesive surface is provided within the area surrounded by the first fixing parts arranged at the four corners of the wiring board.

4. The liquid dispensing head according to claim 2, wherein the adhesive surface is located at a position that includes the intersection of lines connecting the four corners of the first fixing portion arranged diagonally to the wiring board.

5. The liquid dispensing head according to claim 1, wherein the mechanical fixing of the first fixed part is by heat crimping.

6. The liquid dispensing head according to claim 1, wherein the adhesive surface has a height lower than the height of the wiring board receiving surface provided on the wiring board.

7. The liquid dispensing head according to claim 1, wherein the adhesive surface is textured.

8. The liquid dispensing head according to claim 1, further comprising a circulation unit for circulating liquid with the liquid dispensing module.

9. The liquid discharge head according to claim 8, wherein the circulation unit comprises a pump.

10. A housing member comprising a liquid dispensing module for dispensing liquid, and a flow path for supplying liquid to the liquid dispensing module, A wiring board having contact pads on its first surface for electrical connection to a liquid dispensing device, A method for manufacturing a liquid dispensing head having, The process involves mechanically fixing the wiring board and the housing member at the first fixing part, A method for manufacturing a liquid dispensing head, comprising the step of fixing the wiring board with an adhesive at a second fixing portion between a second surface located opposite to the first surface and an adhesive surface provided on the housing member.

11. The method for manufacturing a liquid dispensing head according to claim 10, wherein the adhesive is applied to an adhesive surface provided on the housing member, and then the wiring board and the housing member are mechanically fixed at a plurality of first fixing parts provided at their four corners, and the wiring board and the housing member are fixed with the adhesive at the second fixing part.

12. The method for manufacturing a liquid dispensing head according to claim 10, wherein the adhesive is applied to the second surface of the wiring board so as to align with the adhesive surface provided on the housing member, and then the wiring board and the housing member are mechanically fixed together by a plurality of first fixing parts provided at their four corners, and the wiring board and the housing member are fixed together by the adhesive at the second fixing parts.

13. The method for manufacturing a liquid dispensing head according to any one of claims 10 to 12, wherein the adhesive is of the room-temperature curing type.

Images