JP2025089526A - Liquid ejection head and recording apparatus - Google Patents

Abstract

To increase connection reliability between a discharge member and a flexible substrate.SOLUTION: A liquid discharge head includes a discharge member, a flexible substrate, and a relay substrate. The discharge member includes a plurality of nozzles for discharging a liquid, a plurality of elements for discharging the liquid from the plurality of nozzles, and a plurality of terminals electrically connected to the plurality of elements respectively. The flexible substrate includes a plurality of signal lines corresponding to the plurality of terminals. The relay substrate connects the discharge member and the flexible substrate electrically. The relay substrate includes a plurality of first pads, a plurality of second pads, and a plurality of wiring lines. The plurality of first pads are joined to the plurality of terminals of the discharge member. The plurality of second pads are joined to the plurality of signal lines of the flexible substrate. The plurality of wiring lines connect the plurality of first pads and the plurality of second pads. An area of each of the plurality of second pads is larger than an area of each of the plurality of first pads.SELECTED DRAWING: Figure 6

Description

The disclosed embodiments relate to a liquid ejection head and a recording device.

Inkjet printers and inkjet plotters that use the inkjet recording method are known as printing devices. Such inkjet printing devices are equipped with a liquid ejection head for ejecting liquid.

In such a liquid ejection head, for example, a plurality of individual electrodes provided on the ejection member that ejects the liquid are each joined to a plurality of signal lines on a flexible substrate by an anisotropic conductive bonding material, thereby electrically connecting the ejection member and the flexible substrate.

JP 2005-212238 A

However, conventional liquid ejection heads have room for further improvement in terms of improving the connection reliability between the ejection member and the flexible substrate.

One aspect of the embodiment has been made in consideration of the above, and aims to provide a liquid ejection head and a recording device that can improve the connection reliability between the ejection member and the flexible substrate.

A liquid ejection head according to one aspect of the embodiment includes an ejection member, a flexible substrate, and a relay substrate. The ejection member has a plurality of nozzles for ejecting liquid, a plurality of elements for ejecting liquid from the plurality of nozzles, and a plurality of terminals electrically connected to each of the plurality of elements. The flexible substrate has a plurality of signal lines corresponding to the plurality of terminals. The relay substrate electrically connects the ejection member and the flexible substrate. The relay substrate has a plurality of first pads, a plurality of second pads, and a plurality of wirings. The plurality of first pads are bonded to the plurality of terminals of the ejection member. The plurality of second pads are bonded to the plurality of signal lines of the flexible substrate. The plurality of wirings connect the plurality of first pads and the plurality of second pads. The area of each of the plurality of second pads is larger than the area of each of the plurality of first pads.

According to one aspect of the embodiment, the connection reliability between the discharge member and the flexible substrate can be improved.

FIG. 1 is a front view that illustrates a schematic front view of a printer according to an embodiment. FIG. 2 is a plan view that illustrates a schematic plan view of the printer according to the embodiment. FIG. 3 is a schematic side view showing the internal configuration of the liquid ejection head according to the embodiment. FIG. 4 is a schematic diagram showing a side cross section of the discharge member and the supporting substrate according to the embodiment. FIG. 5 is a schematic side view showing the configurations of the ejection member, relay board, and flexible board according to the embodiment. FIG. 6 is a schematic plan view showing an example of the configuration of a connection portion between the relay substrate and the flexible substrate according to the embodiment. FIG. 7 is a schematic plan view showing another example of the configuration of the connection portion between the relay substrate and the flexible substrate according to the embodiment. FIG. 8 is a schematic side view showing the configurations of the ejection member, relay board, and flexible board according to the first modified example. FIG. 9 is a schematic side view showing the configurations of the ejection member, relay board, and flexible board according to the second modification. FIG. 10 is a schematic side view showing the configurations of the ejection member, relay board, and flexible board according to the third modification. FIG. 11 is a schematic side view showing the configurations of the ejection member, relay board, and flexible board according to the fourth modification. FIG. 12 is a schematic side view showing the internal configuration of a liquid ejection head according to the fifth modified example. FIG. 13 is a schematic side view showing the internal configuration of a liquid ejection head according to the sixth modified example. FIG. 14 is a schematic side view showing the internal configuration of a liquid ejection head according to the seventh modified example. FIG. 15 is a schematic plan view showing an example of the arrangement position of the relay board.

Below, embodiments of the liquid ejection head and recording device disclosed in the present application will be described with reference to the attached drawings. Note that the present disclosure is not limited to the embodiments described below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Furthermore, there may be parts in which the dimensional relationships and ratios differ between the drawings.

In addition, in the embodiments described below, expressions such as "constant," "orthogonal," "vertical," and "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "vertical," or "parallel" in the strict sense. In other words, each of the above expressions allows for deviations due to, for example, manufacturing precision, installation precision, and the like.

Furthermore, each embodiment can be combined as appropriate to the extent that the processing content is not contradictory. Furthermore, the same parts in each of the following embodiments are given the same reference numerals, and duplicate explanations are omitted.

<Printer configuration>
First, an overview of a printer 1, which is an example of a recording apparatus according to an embodiment, will be described with reference to Figures 1 and 2. Figure 1 is a front view that shows a schematic front surface of the printer 1 according to an embodiment. Figure 2 is a plan view that shows a schematic plane surface of the printer 1 according to an embodiment. The printer 1 according to an embodiment is, for example, a color inkjet printer.

As shown in FIG. 1, the printer 1 includes a paper feed roller 2, a guide roller 3, a coater 4, a head case 5, a plurality of transport rollers 6, a plurality of frames 7, a plurality of liquid ejection heads 8, a transport roller 9, a dryer 10, a transport roller 11, a sensor unit 12, and a recovery roller 13. The transport roller 6 is an example of a transport unit.

The printer 1 further includes a control unit 14 that controls each part of the printer 1. The control unit 14 controls the operation of the feed roller 2, the guide roller 3, the applicator 4, the head case 5, the multiple transport rollers 6, the multiple frames 7, the multiple liquid ejection heads 8, the transport roller 9, the dryer 10, the transport roller 11, the sensor unit 12, and the recovery roller 13.

The printer 1 records images and characters on the printing paper P by landing droplets on the printing paper P. The printing paper P is an example of a recording medium. Before use, the printing paper P is wound around the paper feed roller 2. The printer 1 transports the printing paper P from the paper feed roller 2 through the guide roller 3 and the coater 4 to the inside of the head case 5.

The coater 4 applies the coating agent evenly to the printing paper P. This allows the printing paper P to be surface-treated, improving the printing quality of the printer 1.

The head case 5 houses a number of transport rollers 6, a number of frames 7, and a number of liquid ejection heads 8. Inside the head case 5, a space is formed that is isolated from the outside, except for some parts that are connected to the outside, such as the part where the printing paper P enters and exits.

At least one of the control factors such as temperature, humidity, and air pressure of the internal space of the head case 5 is controlled by the control unit 14 as necessary. The transport rollers 6 transport the printing paper P inside the head case 5 to the vicinity of the liquid ejection head 8.

The frame 7 is a rectangular flat plate, and is positioned close to and above the print paper P being transported by the transport rollers 6. As shown in FIG. 2, the frame 7 is positioned so that its longitudinal direction is perpendicular to the transport direction of the print paper P. Inside the head case 5, multiple (e.g., four) frames 7 are positioned at predetermined intervals along the transport direction of the print paper P.

Liquid, such as ink, is supplied to the liquid ejection head 8 from a liquid tank (not shown). The liquid ejection head 8 ejects the liquid supplied from the liquid tank.

The control unit 14 controls the liquid ejection head 8 based on data such as images and characters to eject liquid toward the printing paper P. The distance between the liquid ejection head 8 and the printing paper P is, for example, about 0.5 to 20 mm.

The liquid ejection head 8 is fixed to the frame 7. The liquid ejection head 8 is positioned so that its longitudinal direction is perpendicular to the transport direction of the printing paper P.

That is, the printer 1 according to the embodiment is a so-called line printer in which the liquid ejection head 8 is fixed inside the printer 1. Note that the printer 1 according to the embodiment is not limited to a line printer, and may be a so-called serial printer.

A serial printer is a printer that alternates between moving the liquid ejection head 8 back and forth in a direction that intersects with the transport direction of the print paper P, for example, in a direction that is approximately perpendicular to the direction of transport of the print paper P, to perform recording, and transporting the print paper P.

As shown in FIG. 2, multiple (e.g., five) liquid ejection heads 8 are fixed to one frame 7. FIG. 2 shows an example in which three liquid ejection heads 8 are positioned in front and two in the rear in the transport direction of the print paper P, and the liquid ejection heads 8 are positioned in the transport direction of the print paper P such that the centers of each liquid ejection head 8 do not overlap.

The head group 8A is made up of multiple liquid ejection heads 8 positioned on one frame 7. The four head groups 8A are positioned along the transport direction of the print paper P. Four colors of ink are supplied to the liquid ejection heads 8 that belong to the same head group 8A. This allows the printer 1 to print with four colors of ink using the four head groups 8A.

The colors of ink ejected from each liquid ejection head 8 are, for example, magenta (M), yellow (Y), cyan (C) and black (K). The control unit 14 controls each liquid ejection head 8 to eject multiple colors of ink onto the printing paper P, thereby printing a color image on the printing paper P.

In addition, to treat the surface of the printing paper P, a coating agent may be ejected onto the printing paper P from the liquid ejection head 8.

The number of liquid ejection heads 8 included in one head group 8A and the number of head groups 8A mounted on the printer 1 can be changed as appropriate depending on the object to be printed and the printing conditions. For example, if printing is to be performed within the range that can be printed with one liquid ejection head 8, the number of liquid ejection heads 8 mounted on the printer 1 may be one.

The print paper P that has been printed inside the head case 5 is transported to the outside of the head case 5 by the transport rollers 9 and passes through the inside of the dryer 10. The dryer 10 dries the print paper P that has been printed. The print paper P that has been dried in the dryer 10 is transported by the transport rollers 11 and collected by the collection rollers 13.

In the printer 1, the printing paper P is dried in the dryer 10, which prevents the overlapping printing paper P wound up on the recovery roller 13 from sticking together and preventing the wet liquid from rubbing against each other.

The sensor unit 12 is composed of a position sensor, a speed sensor, a temperature sensor, etc. The control unit 14 can determine the state of each part of the printer 1 based on information from the sensor unit 12 and control each part of the printer 1.

The printer 1 described so far has been shown to use printing paper P as the printing target (i.e., recording medium), but the printing target in the printer 1 is not limited to printing paper P, and the printing target may also be a roll of cloth, etc.

In addition, the printer 1 may transport the print paper P on a transport belt instead of directly transporting it. By using a transport belt, the printer 1 can print on sheets of paper, cut pieces of cloth, wood, tiles, etc.

The printer 1 may also print wiring patterns for electronic devices by ejecting liquid containing conductive particles from the liquid ejection head 8. The printer 1 may also produce chemicals by ejecting a predetermined amount of liquid chemicals or liquid containing chemicals from the liquid ejection head 8 toward a reaction vessel or the like.

The printer 1 may also include a cleaning unit that cleans the liquid ejection head 8. The cleaning unit cleans the liquid ejection head 8, for example, by wiping or capping.

The wiping process is a process of removing liquid adhering to the liquid ejection head 8, for example, by wiping the surface from which the liquid is ejected with a flexible wiper.

The capping process is carried out, for example, as follows. First, a cap is placed over the area from which the liquid is discharged, for example, the second surface 20b of the discharge member 20 (see FIG. 3) (this is called capping). This creates a substantially sealed space between the second surface 20b and the cap.

Next, liquid is repeatedly ejected from this sealed space. This makes it possible to remove liquid with a higher viscosity than the standard state and foreign matter that have been clogging the ejection hole (nozzle) 163 (see Figure 4).

<Configuration of Liquid Ejection Head>
Next, the configuration of the liquid ejection head 8 according to the embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic side view showing the internal configuration of the liquid ejection head 8 according to the embodiment. Fig. 3 shows a side surface perpendicular to the longitudinal direction of the liquid ejection head 8.

The liquid ejection head 8 includes an ejection member 20, a support substrate 30, a relay substrate 40, a flexible substrate 50, a driving IC 60, and a liquid supply member (not shown). The ejection member 20, the support substrate 30, the relay substrate 40, the flexible substrate 50, the driving IC 60, and the liquid supply member are housed in a housing (not shown).

In the following description, for convenience, the direction in which the ejection member 20 is provided in the liquid ejection head 8 may be referred to as "down" and the direction in which the support substrate 30 is provided relative to the ejection member 20 may be referred to as "up."

The ejection member 20 has a generally flat plate shape and has a first surface 20a and a second surface 20b located on the opposite side of the first surface 20a. The first surface 20a has an opening (not shown), and liquid is supplied from the support substrate 30 to the inside of the ejection member 20 through this opening.

The second surface 20b has a plurality of discharge holes 22 (see FIG. 4) that discharge liquid onto the printing paper P. The discharge member 20 has an internal flow path that allows liquid to flow from the first surface 20a to the second surface 20b.

The discharge member 20 has a plurality of displacement elements 23 (see FIG. 4). The plurality of displacement elements 23 are located on the first surface 20a of the discharge member 20.

The support substrate 30 is located on the first surface 20a of the discharge member 20. The support substrate 30 has an internal flow path and supplies the liquid supplied from the liquid supply member to the discharge member 20. The support substrate 30 also has a predetermined thickness that is thicker than the discharge member 20, and has the function of reinforcing the discharge member 20.

A liquid supply member is positioned on the support substrate 30. The liquid supply member has openings (not shown) at both ends in the main scanning direction, which is perpendicular to the sub-scanning direction, which is the transport direction of the printing paper P, and parallel to the printing paper P. The liquid supply member has a flow path inside, and liquid is supplied from the outside through the openings. The liquid supply member supplies liquid to the support substrate 30. The liquid supply member also stores the liquid supplied to the support substrate 30.

The relay substrates 40 are located at two positions on the first surface 20a of the discharge member 20, sandwiching the support substrate 30. One end of the relay substrate 40 is electrically connected to the discharge member 20, and the other end of the relay substrate 40 is electrically connected to the flexible substrate 50. The relay substrate 40 has a function of relaying a signal transmitted by the flexible substrate 50 to the discharge member 20. The height of the relay substrate 40 from the first surface 20a of the discharge member 20 is lower than that of the support substrate 30. This reduces the possibility of interference between the relay substrate 40 and the liquid supply member when placing the liquid supply member on the support substrate 30, thereby improving the degree of freedom in the layout of the liquid supply member.

The flexible substrate 50 is a flexible wiring substrate, and transmits signals sent from the outside to the relay substrate 40. One end of the flexible substrate 50 is electrically connected to the relay substrate 40, and the other end of the flexible substrate 50 is pulled out above the support substrate 30 and is electrically connected to a wiring substrate (not shown).

The driving IC 60 is mounted on the flexible substrate 50. The driving IC 60 drives each displacement element 23 in the ejection member 20 based on a driving signal sent from the control unit 14 (see FIG. 1). This allows the driving IC 60 to control the driving of the liquid ejection head 8.

Note that FIG. 3 shows an example of the configuration of the liquid ejection head 8, and it may further include components other than those shown in FIG. 3.

<Configuration of Discharge Member and Support Substrate>
Next, the configurations of the discharge member 20 and the support substrate 30 according to the embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing a side cross section of the discharge member 20 and the support substrate 30 according to the embodiment.

As shown in FIG. 4, the discharge member 20 has a plurality of pressure chambers 21, a plurality of discharge holes 22, a plurality of displacement elements 23, and a plurality of terminals 24.

The multiple pressure chambers 21 are each connected to multiple flow paths 31 in the support substrate 30. The multiple discharge holes 22 are each connected to the multiple pressure chambers 21. The multiple displacement elements 23 are located on the first surface 20a of the discharge member 20 at multiple positions corresponding to the multiple pressure chambers 21.

The multiple terminals 24 are located on the first surface 20a of the discharge member 20 at positions sandwiching the support substrate 30. The multiple terminals 24 are electrically connected to the multiple displacement elements 23 via electrodes and wiring (not shown). The multiple terminals 24 are electrically connected to the multiple signal lines in the flexible substrate 50. When a signal transmitted by the flexible substrate 50 is input from the terminal 24 to the displacement element 23, the displacement element 23 is displaced.

The support substrate 30 is located on the first surface 20a of the discharge member 20. The support substrate 30 has a plurality of spaces on the lower surface for accommodating a plurality of displacement elements 23, respectively. The support substrate 30 has a plurality of flow paths 31 therein. The plurality of flow paths 31 are connected to the plurality of pressure chambers 21, respectively. The plurality of flow paths 31 open to the upper surface of the support substrate 30. In addition, a liquid supply member (not shown) is located on the upper surface of the support substrate 30. The plurality of flow paths 31 are connected to the liquid supply member.

When liquid is supplied from the liquid supply member through the flow path 31 to the inside of the discharge member 20, the corresponding displacement element 23 is displaced, thereby pressing the pressure chamber 21 and discharging the liquid from the discharge hole 22. In other words, the multiple displacement elements 23 function as multiple elements that cause the liquid to be discharged from the multiple discharge holes 22.

As shown in FIG. 4, the discharge member 20 has a laminated structure in which a nozzle plate 20A and an actuator plate 20B are laminated. The nozzle plate 20A has a plurality of discharge holes 22. The actuator plate 20B has a plurality of pressure chambers 21, a plurality of displacement elements 23, and a plurality of terminals 24. The nozzle plate 20A and the actuator plate 20B are aligned and laminated, so that the plurality of pressure chambers 21 and the plurality of discharge holes 22 communicate with each other to form the discharge member 20.

<Connection of the Discharge Member, Intermediate Board, and Flexible Board>
Next, the connection state of the discharge member 20, relay substrate 40, and flexible substrate 50 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a schematic side view showing the configuration of the discharge member 20, relay substrate 40, and flexible substrate 50 according to the embodiment. Fig. 6 is a schematic plan view showing an example of the configuration of the connection portion between the relay substrate 40 and flexible substrate 50 according to the embodiment. Fig. 6 shows the lower surface of the relay substrate 40 (i.e., the surface facing the discharge member 20).

5, a plurality of terminals 24 (see FIG. 4) are located on the first surface 20a of the discharge member 20, and a plurality of signal lines 51 (see FIG. 6) corresponding to the plurality of terminals 24 are located on the surface of the flexible substrate 50. One end of the relay substrate 40 is connected to the plurality of terminals 24 of the discharge member 20, and the other end of the relay substrate 40 is connected to the plurality of signal lines 51 of the flexible substrate 50. That is, a plurality of first pads 41 (see FIG. 6) are formed on one end of the relay substrate 40, and these plurality of first pads 41 and the plurality of terminals 24 of the discharge member 20 are bonded by a conductive bonding material 401. In addition, a plurality of second pads 42 (see FIG. 6) are formed on the other end of the relay substrate 40, and these plurality of second pads 42 and the plurality of signal lines 51 of the flexible substrate 50 are bonded by a conductive bonding material 402. The plurality of first pads 41 and the plurality of second pads 42 are connected to each other by a plurality of wirings 43. The conductive bonding materials 401 and 402 can be, for example, anisotropic conductive films (ACFs).

6, in the relay board 40, the area of each of the multiple second pads 42 is larger than the area of each of the multiple first pads 41. In this way, by increasing the area of each of the multiple second pads 42 that are joined to the multiple signal lines 51 of the flexible board 50, it is possible to suppress poor connection between the flexible board 50 and the relay board 40. That is, when the flexible board 50 is connected to the relay board 40, a mechanical load is applied to the signal line 51 from the second pad 42 due to bending of the flexible board 50, but by increasing the area of the second pad 42, the mechanical load on the signal line 51 can be reduced. In addition, when the flexible board 50 is connected to the relay board 40, the conductive bonding material 402 is melted by heating, so that thermal expansion of the flexible board 50 occurs, and the position of the signal line 51 from the second pad 42 is likely to be shifted. Even in such a case, by increasing the area of the second pad 42, the electrical connection between the second pad 42 and the signal line 51 can be ensured even if the position of the signal line 51 is shifted. Since connection failure between the flexible substrate 50 and the relay substrate 40 can be suppressed, the relay substrate 40 can stably connect the flexible substrate 50 and the discharge member 20. As a result, the liquid discharge head 8 according to the embodiment can improve the connection reliability between the discharge member 20 and the flexible substrate 50. The areas of the first pad 41 and the second pad 42 are the planar areas of the relay substrate 40 when viewed from above.

The second pads 42 are located in a number of (here, two) regions 421 aligned along a direction from one end of the relay substrate 40 on the discharge member 20 side toward the other end (hereinafter referred to as the "first direction") so as not to be adjacent to each other in a second direction intersecting the first direction. This allows the size of the second pads 42 along the second direction to be increased to an extent that the second pads 42 do not interfere with each other, thereby making it possible to further increase the area of the second pads 42.

As shown in Figures 5 and 6, the first pads 41, the second pads 42, and the wiring 43 are located on the lower surface of the relay substrate 40 facing the discharge member 20. In this way, by locating the first pads 41, the second pads 42, and the wiring 43 on the same surface, the lower surface of the relay substrate 40, the length of the wiring 43 can be minimized, and the electrical resistance in the relay substrate 40 can be reduced.

6 shows an example in which the area of the second pads 42 is increased by positioning the second pads 42 so that they are not adjacent to each other, but the structure for increasing the area of the second pads 42 on the relay substrate 40 is not limited to this. For example, as shown in FIG. 7, the area of the second pads 42 may be increased by changing the pitch of the wirings 43 on the relay substrate 40. FIG. 7 is a plan view schematic diagram showing another example of the configuration of the connection between the relay substrate 40 and the flexible substrate 50 according to the embodiment. The wirings 43 shown in FIG. 7 are pitch-changed on the relay substrate 40, and the pitch (spacing) between the wirings 43 is small on the side of the first pads 41, but is large on the side of the second pads 42. This allows the size of the second pads 42 along the second direction to be increased within a range in which the second pads 42 do not interfere with each other, thereby making it possible to further increase the area of the second pads 42.

<Method of Manufacturing Liquid Ejection Head>
Next, a method for manufacturing the liquid ejection head 8 according to the embodiment will be described. First, the support substrate 30 is placed on the first surface 20a of the ejection member 20. Next, the nozzle plate 20A and the actuator plate 20B are aligned and stacked to create a laminated structure of the ejection member 20. Next, the relay substrate 40 and the ejection member 20 are electrically connected by bonding the first pads 41 of the relay substrate 40 to the terminals 24 of the ejection member 20 with a conductive bonding material 401. Next, the relay substrate 40 and the ejection member 20 are electrically connected by bonding the second pads 42 of the relay substrate 40 to the signal lines 51 of the flexible substrate 50 with a conductive bonding material 402. After that, a liquid supply member is placed on the support substrate 30, and the ejection member 20 and other members (and other members as necessary) are housed in the housing. This results in the liquid ejection head 8 according to the embodiment.

<Various modified examples>
8 is a side schematic diagram showing the configuration of the discharge member 20, relay substrate 40, and flexible substrate 50 according to the first modified example. The flexible substrate 50 shown in FIG. 8 does not have a driving IC 60 mounted thereon, and the driving IC 60 is located on the lower surface of the relay substrate 40 (i.e., the surface facing the discharge member 20). By positioning the driving IC 60 on the lower surface of the relay substrate 40 in this manner, the wiring length between the driving IC 60 and the discharge member 20 can be shortened, and therefore the resistance loss between the driving IC 60 and the discharge member 20 can be reduced. In addition, the possibility of disconnection between the driving IC 60 and the discharge member 20 can be reduced, and therefore the connection reliability between the driving IC 60 and the discharge member 20 can be improved.

In addition, in FIG. 8, a heat dissipation member may be provided on the upper surface of the relay substrate 40 opposite the driving IC 60. This improves the heat dissipation of the driving IC 60. The heat dissipation member may be a heat dissipation fin, a Peltier element, or the like. The driving IC 60 may also be covered with a protective cover. This prevents the liquid ejected from the ejection member 20 from adhering to the driving IC 60.

9 is a schematic side view showing the configuration of the discharge member 20, relay board 40 and flexible board 50 according to the second modification. In the relay board 40 shown in FIG. 9, the first pads 41 are located on the lower surface of the relay board 40 facing the discharge member 20. The second pads 42 are located on the upper surface of the relay board. The wiring 43 is routed to the upper and lower surfaces of the relay board 40 via the side surfaces of the relay board 40. In this way, the first pads 41 and the second pads 42 are located on the lower and upper surfaces of the relay board 40, so that the discharge member 20 and the flexible board 50 can be electrically connected on different surfaces of the relay board 40. As a result, even if the width from one end to the other end of the relay board 40 on the discharge member 20 side is reduced, interference between the discharge member 20 and the flexible board 50 is avoided, which can promote miniaturization of the liquid discharge head 8.

In FIG. 9, the multiple wirings 43 may be positioned so as to penetrate the bottom and top surfaces of the relay substrate 40. This allows the length of the multiple wirings 43 to be shortened, and the electrical resistance in the relay substrate 40 to be reduced.

Figure 10 is a schematic side view showing the configuration of the ejection member 20, relay substrate 40, and flexible substrate 50 according to variant 3. Variation 3 differs from variant 2 in the structure of the relay substrate 40. In the relay substrate 40 shown in Figure 10, the multiple second pads 42 are positioned so as to overlap the multiple first pads 41 in a plan view. This allows the width from one end of the relay substrate 40 on the ejection member 20 side to the other end to be minimized, further facilitating miniaturization of the liquid ejection head 8.

Figure 11 is a schematic side view showing the configuration of the discharge member 20, relay substrate 40, and flexible substrate 50 according to variant example 4. The flexible substrate 50 shown in Figure 11 does not have a driving IC 60 mounted thereon, and the driving IC 60 is located on the top surface of the relay substrate 40 (i.e., the surface opposite to the surface facing the discharge member 20). By positioning the driving IC 60 on the top surface of the relay substrate 40 in this way, the driving IC 60 can be protected from the liquid discharged from the discharge member 20.

12 is a schematic side view showing the internal structure of the liquid ejection head 8 according to the fifth modified example. The liquid ejection head 8 shown in FIG. 12 differs from the liquid ejection head 8 shown in FIG. 3 in the structure of the relay substrate 40. As shown in FIG. 12, the relay substrate 40 and the support substrate 30 are located on the ejection member 20, and the height of the relay substrate 40 from the first surface 20a of the ejection member 20 is higher than that of the support substrate 30. In other words, the thickness of the relay substrate 40 is thicker than that of the support substrate 30. By increasing the thickness of the relay substrate 40 in this way, the strength of the relay substrate 40 can be improved. In addition, when a liquid supply member is placed on the support substrate 30, the relay substrate 40 can be used as a buffer material to reduce the load applied to the support substrate 30 from the liquid supply member.

Figure 13 is a schematic side view showing the internal structure of a liquid ejection head 8 according to Modification 6. The liquid ejection head 8 shown in Figure 13 differs from the liquid ejection head 8 shown in Figure 3 in that the relay substrate 40 (see Figure 6) and the support substrate 30 are integrated. In other words, the relay substrate 40 and the support substrate 30 may be formed from the same material. In the example of the liquid ejection head 8 according to Modification 6, the support substrate 30 having the function of the relay substrate 40 is positioned on the ejection member 20. By integrating the relay substrate 40 and the support substrate 30 in this way, the gap between the relay substrate 40 and the support substrate 30 is eliminated, which facilitates miniaturization of the liquid ejection head 8.

Figure 14 is a schematic side view showing the internal structure of a liquid ejection head 8 according to the seventh modified example. The liquid ejection head 8 shown in Figure 14 differs from the liquid ejection head 8 shown in Figure 13 in that the driving IC 60 is located on the underside of the support substrate 30 (i.e., the surface facing the ejection member 20). By positioning the driving IC 60 on the underside of the support substrate 30 in this way, the wiring length between the driving IC 60 and the ejection member 20 can be shortened, and the resistance loss between the driving IC 60 and the ejection member 20 can be reduced. In addition, the possibility of disconnection between the driving IC 60 and the ejection member 20 can be reduced, and therefore the connection reliability between the driving IC 60 and the ejection member 20 can be improved.

In FIG. 14, the driving IC 60 may be located on the upper surface of the support substrate 30 (i.e., the surface opposite to the surface facing the discharge member 20). In this way, by positioning the driving IC 60 on the upper surface of the support substrate 30, the driving IC 60 can be protected from the liquid discharged from the discharge member 20.

In addition, in FIG. 14, the driving IC 60 may be formed from a low-temperature polysilicon (LTPS) film. This allows the driving IC 60 to be made smaller.

<Other Modifications>
In the above embodiment, an example in which the relay substrate 40 is located at each of two positions sandwiching the support substrate 30 on the first surface 20a of the discharge member 20 has been shown, but the position of the relay substrate 40 is not limited to this. For example, the relay substrate 40 may be located at a position surrounding the support substrate 30 on the first surface 20a of the discharge member 20 as shown in FIG. 15. That is, the shape of the relay substrate 40 may be a rectangular frame shape surrounding the support substrate 30 on the first surface 20a of the discharge member 20. This can improve the strength of the relay substrate 40. Note that FIG. 15 is a schematic plan view showing an example of the position of the relay substrate 40. In FIG. 15, the discharge member 20, the support substrate 30, and the relay substrate 40 are shown as viewed from the first surface 20a side.

As described above, the liquid ejection head (e.g., liquid ejection head 8) according to the embodiment includes an ejection member (e.g., ejection member 20), a flexible substrate (e.g., flexible substrate 50), and a relay substrate (e.g., relay substrate 40). The ejection member has a plurality of nozzles (e.g., ejection holes 22) that eject liquid, a plurality of elements (e.g., displacement elements 23) that eject liquid from the plurality of nozzles, and a plurality of terminals (e.g., terminals 24) electrically connected to each of the plurality of elements. The flexible substrate has a plurality of signal lines (e.g., signal lines 51) corresponding to the plurality of terminals. The relay substrate electrically connects the ejection member and the flexible substrate. The relay substrate has a plurality of first pads (e.g., first pads 41), a plurality of second pads (e.g., second pads 42), and a plurality of wirings (e.g., wiring 43). The plurality of first pads are bonded to a plurality of terminals of the ejection member. The plurality of second pads are bonded to a plurality of signal lines of the flexible substrate. The multiple wirings connect the multiple first pads and the multiple second pads. The area of each of the multiple second pads is larger than the area of each of the multiple first pads. As a result, the liquid ejection head according to the embodiment can improve the connection reliability between the ejection member and the flexible substrate.

The second pads may also be positioned in a number of regions (e.g., region 421) aligned along a first direction from one end of the relay board toward the other end on the ejection member side, so as not to be adjacent to each other in a second direction intersecting the first direction. This allows the liquid ejection head according to the embodiment to have a larger area for the second pads.

The relay substrate may also have a plurality of wirings that are spaced apart from one another at one end connected to the plurality of second pads, compared to the other end connected to the plurality of first pads. This allows the liquid ejection head according to the embodiment to have a larger area for the second pads.

The relay substrate may also have a first surface (e.g., a bottom surface) facing the ejection member, and a second surface (e.g., a top surface) located opposite the first surface. The first pads, the second pads, and the wiring may be located on the first surface. As a result, according to the liquid ejection head of the embodiment, the length of the wiring can be minimized, and the electrical resistance in the relay substrate can be reduced.

The liquid ejection head may further include a driving IC (e.g., driving IC 60) that controls the driving of the ejection member. The driving IC may be located on the first surface. As a result, according to the liquid ejection head of the embodiment, the resistance loss between the driving IC and the ejection member can be reduced. Also, the connection reliability between the driving IC and the ejection member can be improved.

The relay board may have a first surface facing the ejection member, a second surface located on the opposite side of the first surface, and a side surface connecting the first surface and the second surface. The first pads may be located on the first surface. The second pads may be located on the second surface. The wiring may be routed to the first surface and the second surface via the side surface, or may be located penetrating the first surface and the second surface. As a result, according to the liquid ejection head of the embodiment, even if the width from one end to the other end on the ejection member side of the relay board is reduced, interference between the ejection member and the flexible board is avoided, which promotes miniaturization of the liquid ejection head.

The second pads may be positioned so as to overlap the first pads in a plan view. This allows the liquid ejection head according to the embodiment to minimize the width from one end of the relay board on the ejection member side to the other end, further facilitating miniaturization of the liquid ejection head.

The liquid ejection head may further include a driving IC (e.g., driving IC 60) that controls the driving of the ejection member. The driving IC may be located on the second surface. As a result, according to the liquid ejection head of the embodiment, the driving IC can be protected from the liquid ejected from the ejection member.

The liquid ejection head may further include a support substrate (e.g., support substrate 30) located above the ejection member and having a flow path (e.g., flow path 31) through which liquid supplied to the ejection member flows. As a result, the liquid ejection head according to the embodiment can supply liquid to the ejection member while reinforcing the ejection member with the support substrate.

The relay substrate may be located above the ejection member. The relay substrate may be lower in height from the ejection member than the support substrate. As a result, with the liquid ejection head according to the embodiment, the possibility of interference between the relay substrate and the liquid supply member when placing the liquid supply member on the support substrate can be reduced, thereby improving the freedom of layout of the liquid supply member.

The relay substrate may be located above the ejection member. The height of the relay substrate from the ejection member may be greater than the support substrate. This allows the liquid ejection head according to the embodiment to have an improved strength of the relay substrate. Furthermore, when placing the liquid supply member on the support substrate, the relay substrate can be used as a buffer material to reduce the load applied from the liquid supply member to the support substrate.

The intermediate substrate and the support substrate may also be integrated. This eliminates any gaps between the intermediate substrate and the support substrate in the liquid ejection head according to the embodiment, facilitating miniaturization of the liquid ejection head.

The support substrate may also have a first surface (e.g., a bottom surface) facing the ejection member, and a second surface (e.g., a top surface) located on the opposite side of the first surface. The liquid ejection head may further include a driving IC that controls the driving of the ejection member. The driving IC may be located on the first surface or the second surface. As a result, according to the liquid ejection head of the embodiment, it is possible to reduce resistance loss between the driving IC and the ejection member. It is also possible to improve the connection reliability between the driving IC and the ejection member. It is also possible to protect the driving IC from liquid ejected from the ejection member.

The driving IC may also be formed from a low-temperature polysilicon film. This allows the driving IC to be miniaturized according to the liquid ejection head of the embodiment.

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof.

REFERENCE SIGNS LIST 1 Printer 8 Liquid ejection head 14 Control unit 20 Ejection member 21 Pressure chamber 22 Ejection hole 23 Displacement element 24 Terminal 30 Support substrate 31 Flow path 40 Intermediate substrate 41 First pad 42 Second pad 43 Wiring 50 Flexible substrate 51 Signal line 60 Drive IC
421 Area

Claims (15)

an ejection member having a plurality of nozzles for ejecting liquid, a plurality of elements for ejecting liquid from the plurality of nozzles, and a plurality of terminals electrically connected to the plurality of elements,
a flexible substrate having a plurality of signal lines corresponding to the plurality of terminals;
a relay substrate that electrically connects the discharge member and the flexible substrate,
The relay substrate is
A plurality of first pads joined to the plurality of terminals of the discharge member;
a plurality of second pads joined to the plurality of signal lines of the flexible substrate;
a plurality of wirings connecting the plurality of first pads and the plurality of second pads;
A liquid ejection head, wherein an area of each of the plurality of second pads is larger than an area of each of the plurality of first pads. The liquid ejection head according to claim 1, wherein the second pads are positioned in a plurality of regions aligned along a first direction from one end of the relay board toward the other end of the relay board on the ejection member side, so as not to be adjacent to each other in a second direction intersecting the first direction. The relay substrate is
The liquid ejection head according to claim 1 , further comprising a plurality of wirings, the wirings having a larger distance between each other end connected to the plurality of second pads than between each other end connected to the plurality of first pads. the relay substrate has a first surface facing the ejection member and a second surface located opposite to the first surface;
The liquid ejection head according to claim 1 , wherein the first pads, the second pads and the wirings are located on the first surface. A driving IC for controlling the driving of the ejection member is further provided.
The liquid ejection head according to claim 4 , wherein the driving IC is located on the first surface. the relay substrate has a first surface facing the ejection member, a second surface located opposite to the first surface, and a side surface connecting the first surface and the second surface;
the first pads are located on the first surface;
the second pads are located on the second surface;
The liquid ejection head according to claim 1 , wherein the plurality of wirings are positioned by being routed to the first surface and the second surface via the side surfaces, or are positioned by penetrating the first surface and the second surface. The liquid ejection head according to claim 6, wherein the second pads are positioned so as to overlap the first pads in a plan view. A driving IC for controlling the driving of the ejection member is further provided.
The liquid ejection head according to claim 6 , wherein the driving IC is located on the second surface. The liquid ejection head according to claim 1, further comprising a support substrate located above the ejection member and having a flow path therein through which the liquid supplied to the ejection member flows. the relay board is located on the ejection member,
The liquid ejection head according to claim 9 , wherein the intermediate substrate is lower in height from the ejection member than the support substrate. the relay board is located on the ejection member,
The liquid ejection head according to claim 9 , wherein the intermediate substrate is higher in height from the ejection member than the support substrate. The liquid ejection head according to claim 9, wherein the relay substrate and the support substrate are integrated. the support substrate has a first surface facing the ejection member and a second surface located opposite the first surface;
A driving IC for controlling the driving of the ejection member is further provided.
The liquid ejection head according to claim 12 , wherein the driving IC is located on the first surface or the second surface. The liquid ejection head according to claim 13, wherein the driving IC is formed from a low-temperature polysilicon (LTPS) film. A recording device equipped with a liquid ejection head according to any one of claims 1 to 14.

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