JP2003086913A - Structure and method for connecting flexible wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure and a method for connecting a flexible wiring board capable of surely connecting an output terminal land on a circuit board with an input terminal land on the flexible wiring board. SOLUTION: The input terminal land provided on the flexible wiring board 24 and a terminal land provided on the circuit board 21 are aligned, and solder H applied beforehand is bar-heated from the opposite side of the wiring board 24 to fuse the solder to achieve soldered connection. At that time, the excess portion of the fused solder H flows into a through-hole 72 bored in the terminal land provided on the circuit board 21 so that the solder can be prevented from flowing into or flowing out from between respective terminal lands. Further, the through-hole 72 is not located together with the terminal land on a concentric circle, and respective terminal lands can surely be connected by soldering whether the terminal area is large or small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible wiring board connecting structure and a connecting method for connecting an input terminal land on a flexible wiring board and an output terminal land on a circuit board.

[0002]

2. Description of the Related Art Conventionally, flexible wiring boards have been used to supply power and signals inside electronic equipment. By connecting the two circuit boards and other parts connected by this flexible wiring board by the flexible wiring board through a narrow place or a bent path, both parts can be arranged at arbitrary places. , The degree of freedom in designing electronic devices has increased,
In particular, it is effective in reducing the size of equipment by reducing wasted space. In order to connect the conductor wire of the flexible wiring board and the conductor wire of the circuit board, terminal lands are provided on both boards, a solder layer is provided on one of both terminal lands, and the solder layer is melted by applying pressure while heating. Let me connect both terminal land.

[0003]

However, as the number of conductors on the flexible wiring board increases and the density increases as the functions of the equipment become more sophisticated, the pitch between the terminal lands becomes narrower and the distance between the terminal lands becomes smaller. In order to prevent the outflow and inflow of the solder, it is necessary to strictly control the amount of solder supplied or the thickness of the solder plating, and if the amount of solder fluctuates, a short circuit or connection failure may occur due to the outflow of solder between the terminals. There was a problem to do.

The present invention has been made to solve the above problems, and provides a flexible wiring board connection structure and a connection method capable of reliably connecting a terminal land on a circuit board and a terminal land on a flexible wiring board. The purpose is to provide.

[0005]

In the flexible wiring board connection structure of the invention according to claim 1 for achieving the above object, a flexible wiring board having a plurality of conductors on a flexible band-shaped insulator. And a circuit board having a wiring pattern connected to the plurality of conductors of the flexible wiring board, and formed at the end of the conductor on the flexible wiring board and the end of the wiring pattern on the circuit board, respectively. In a connection structure of a flexible wiring board for soldering the formed terminal lands to each other, in the terminal land of the circuit board, a through hole penetrating the circuit board is formed, and a terminal of the flexible wiring board facing the through hole is formed. The land is closed, and the terminal land of the flexible wiring board and the terminal land of the circuit board are connected with solder. It has a structure, characterized in that the excess portion of the solder was melted and configured to release the through hole while.

In the flexible wiring board connection structure of this structure, the terminal land of the circuit board is formed with a through hole penetrating the circuit board, and the terminal land of the flexible wiring board facing the through hole is closed. Since it has a shape, it is possible to satisfactorily heat and pressurize the melted solder on the outside of the flexible wiring board from the side of the flexible wiring board, and as a result, the entire solder is efficiently heated and melted sufficiently to face each other. The terminal lands can be surely connected to each other, and the excess portion of the solder can be prevented from escaping to the through hole and short-circuiting between the adjacent terminal lands.

In addition, in the flexible wiring board connection structure of the invention according to claim 2, in addition to the configuration of the flexible wiring board connection structure according to claim 1, the through hole is a terminal land on the circuit board. It is characterized in that it is provided at a position that is not coaxial with.

In the flexible wiring board connection structure having this structure, in addition to the effect of the invention described in claim 1, the through hole is formed at a position not coaxial with the terminal land on the circuit board. Even if the area of the terminal lands is small, excess solder can be poured into the through holes to firmly connect the terminal lands.

Further, in the method for connecting a flexible wiring board according to a third aspect of the present invention, a flexible wiring board having a plurality of conducting wires on a flexible band-shaped insulator, and a plurality of conducting wires of the flexible wiring board are provided. A circuit board having a wiring pattern to be connected, and soldering the terminal lands formed at the ends of the conductor on the flexible wiring board and the ends of the wiring pattern on the circuit board to each other, In the flexible wiring board connecting method, a through hole penetrating the circuit board is formed in the terminal land of the circuit board, and the terminal land of the flexible wiring board facing the through hole is formed in a closed shape, The terminal land of the wiring board and the terminal land of the circuit board are opposed to each other with solder interposed therebetween, Heat and pressure are applied from the side opposite to the terminal land of the flexible wiring board to connect the terminal land of the flexible wiring board and the terminal land of the circuit board with melted solder, and the surplus portion of the solder is passed through the through hole. It has a structure that allows it to escape to the hall.

In the flexible wiring board connecting method of this structure, the terminal land of the circuit board is formed with a through hole penetrating the circuit board, and the terminal land of the flexible wiring board facing the through hole is closed. When the terminal lands of the flexible wiring board and the terminal lands of the circuit board are opposed to each other with solder interposed therebetween, and heat and pressure are applied from the side opposite to the terminal lands of the flexible wiring board. It is possible to perform the heating and pressurizing work well without the melted solder escaping to the outside of the board, and as a result, the entire solder is efficiently heated and melted sufficiently to ensure the space between the opposing terminal lands. While connecting, the surplus part of the solder escapes to the through hole,
It is possible to prevent a short circuit between adjacent terminal lands.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings embodied in a recording apparatus. First, the internal structure of the recording apparatus, that is, the inkjet printer 1 will be described with reference to FIG. FIG. 1 is a perspective view showing the internal structure of the inkjet printer 1.

As shown in FIG. 1, a carriage 8 is provided inside a housing 2 of an ink jet printer 1. The carriage 8 is slidably supported by a guide rod 11 and a guide member 12, respectively. It is fixed to the belt 13 and driven by the CR motor 16 to reciprocate. A recording head unit 17 having recording heads 19 and 20 (see FIG. 2) for performing recording such as printing is attached to the carriage 8. The recording heads 19 and 20 have four color inks (cyan c, magenta m,
The recording paper P, which is a recording medium, including yellow y and black b)
It is an ink jet type that ejects ink droplets on the top to perform a recording operation, and cyan, magenta, yellow, and
Four black jet nozzle groups 7a to 7d (see FIG. 2)
Is equipped with.

Further, the recording head unit 17 has four ink cartridges 14y, 14m, 14c and 14b for supplying the inks of the respective colors to the ejection nozzle groups 7a to 7d.
Is detachably mounted. Further, in the inkjet printer 1 of the present embodiment, a platen roller 10 that conveys the recording paper P is provided at a position facing the recording heads 19 and 20, and the platen roller 10 is L (not shown).
The platen roller 1 is driven to rotate by driving the F motor.
With the rotation of 0, the recording paper P is conveyed in the direction (arrow direction shown in FIG. 1) orthogonal to the moving direction of the carriage 8.

Next, the structure of the recording head unit 17 will be described with reference to FIGS. 2 and 3
FIG. 3 is a perspective view of the recording head unit 17 as viewed from the back side of its bottom. As shown in FIGS. 2 and 3, the recording head unit 17 includes a head holder 18, recording heads 19 and 20, a circuit board 21, and a head cover 70.
Flexible wiring boards 24, 25 and an elastic material 27 (see FIG.
6) and each member is provided in the head holder 18. The cover plate / heat sink 26 is connected to the flexible wiring boards 24, 25.
On the opposite side of the head holder 18,
8 is provided. The head holder 18 is held by the carriage 8 shown in FIG. 1 and reciprocates together with the carriage 8.

The head holder 18 is integrally molded of a synthetic resin material, and has a bottom wall 18a, a back wall 18b and a left side wall 18c.
(See FIG. 4), the right side wall 18d and the front wall 18e, and has a substantially box shape with an open upper surface. The ink cartridges 14y, 14m, 14c, 14b described above
Is detachably mounted in this open portion. In addition, the outer surface 18 of the bottom wall 18 a of the head holder 18
A head holding portion 28 (see FIG. 7) is formed in a1, and two recording heads 19 and 20 for performing recording on the recording paper P are juxtaposed and adhesively fixed to the head holding portion 28. The recording head 1 is provided on the outer surface 18b1 of the back wall 18b.
Circuit board 2 serving as a relay board between the carriages 9 and 20
1 is fixed.

The recording heads 19 and 20 and the circuit board 2 are also provided.
Flexible wiring boards 24 and 25 are connected between the first and second terminals. In the present embodiment, the plate-type piezoelectric actuators 12 provided on the recording heads 19 and 20 respectively.
An IC chip is used as a drive circuit that generates a drive voltage for driving 0 (see FIG. 10).
IC chips 22 and 23 for are mounted on the surface not on the head holder 18 side.

Then, as shown in FIG. 4, the recording head unit 17 is attached to the carriage 8 so as to be movable. More specifically, the projections 38 a and 38 b projecting from the back wall 18 b of the head holder 18 are fitted into the through holes 79 provided in the carriage 8, respectively, whereby the recording head unit 17 is positioned on the carriage 8. It is attached by known fixing means. A wiring board 80 is provided on the carriage 8. The wiring board 80 is connected to the main body side control board fixed to the stationary position of the housing 2 of the printer via a flexible wiring board (not shown), and the connection portion 80a of the wiring board 80 is connected.
Is connected to a contact 55 (see FIG. 2) on the circuit board 21 provided on the head holder 18, and the IC chip on the flexible wiring boards 24 and 25 from the main body side control board via the wiring board 80 of the carriage 8. Power and signals are supplied to 22 and 23, respectively.

Next, the structure of the head holder 18 will be described with reference to FIGS. 7 and 8. FIG. 7 is a perspective view of the head holder 18 as seen from the back side of the bottom thereof.
FIG. 3 is a perspective view of the head holder 18 as viewed from the front side of the upper part thereof. As described above, the head holder 18 has a substantially box shape composed of five wall portions, and as shown in FIGS. 7 and 8, the bottom wall 18a, the back wall 18b, and the front wall 18e are
Both have a substantially rectangular shape, and the height of the front wall 18e is
It is approximately one fourth of the height of the back wall 18b. Further, the left side wall 18c and the right side wall 18d are both the bottom wall 18a and the back wall 1a.
It has a substantially triangular shape with a right-angled portion on the side of the intersection with 8b. The right side wall 18d has an inclined surface 18d1 cut out at a predetermined angle at its right angle portion.

Further, on the bottom wall 18a of the head holder 18, the ink cartridges 14y, 14m, 14c and 14b mounted on the open portion on the upper surface side of the head holder 18,
A plurality of ink supply passages (not shown) that can be connected to the ink discharge portion (not shown) are provided. Each ink supply passage penetrates the bottom wall 18a and opens to the head holding portion 28, and is connected to an ink flow passage corresponding to each ejection nozzle group 7a to 7d of each recording head 19 and 20.

On the outer surface 18b1 of the back wall 18b of the head holder 18, two substantially rectangular ribs 35a, 35 are provided.
b is provided in a convex shape, and the tips of the ribs 35a and 35b are in contact with the back surface of the circuit board 21 (see FIG. 2). Protrusions 36 and 37 are provided on the outer side surface 18b1. The protrusions 36 and 37 have through-holes 21 formed in the circuit board 21 at their tip end cylindrical portions 36a and 37a.
The circuit board 21 is fixed by being inserted into a and 21b (see FIG. 13) and thermally crushed.

The head holder 18 has a heat sink 2 on the outer surface side near the intersection of the bottom wall 18a and the back wall 18b.
It is designed to hold 6. That is, the inclined surface 18 of the right wall 18d is provided near the end of the bottom wall 18a on the left wall 18c side.
A heat sink holding wall 40 formed to be substantially parallel to the portion near d1 is provided in a protruding manner. The heat sink holding wall 40 has an inclined surface parallel to the inclined surface 18d1. Right side wall 18
A rib 35c connects between d and the heat sink holding wall 40. Heat sink holding wall 40 and right side wall 1
The heat sink contact portion 40a is formed stepwise on the surface facing 8d.
The heat sink contact portion 40a is formed continuously with the heat sink contact portion 40a in the vicinity of the rear wall 18b side end of the outer surface 18a1 of the bottom wall 18a.

The heat sink 26 has its outer periphery abutted against the heat sink abutting portions 40a, 48 and is hermetically fixed to the head holder 18 with an adhesive or the like. Further, the sealant 71 (see FIG. 6) is filled between the heat sink 26 and the head cover 70 described later, and also between the heat sink 26 and the circuit board 21, and ink or the like is applied to the recording heads 19 and 20 and the flexible wiring boards 24 and 25. Are prevented from entering. A seal between the circuit board 21 and the rib 35c can also be provided if necessary. The heat sink 26 is made of a metal material having a good heat dissipation effect, such as aluminum, and has a plate shape.

Further, on the outer surface of the back wall 18b near the intersection with the bottom wall 18a, that is, inside the heat sink 26 fixed to the head holder 18, an elastic material for mounting an elastic material 27, which will be described later, is placed. A mounting portion 29 is provided. The elastic material mounting portion 29 is composed of a plurality of ribs having oblique sides parallel to the inclined surface 18d1 of the right wall portion 18d, and the oblique sides of these ribs form inclined wall surfaces for adhesively fixing the elastic material 27. There is.

Next, the structure of the flexible wiring boards 24 and 25 will be described with reference to FIG. As shown in FIG. 9, the flexible wiring board 24 is composed of a strip-shaped insulator 41 made of a polyimide resin having flexibility and a plurality of conductive wires provided on the strip-shaped insulator 41. The strip-shaped insulator 41 is a substantially rectangular head connecting portion 42 that is connected to the piezoelectric actuator 120 of the recording head 19 in an overlapping manner, and a substantially rectangular shape that is widened from one end of the head connecting portion 42 on the short side. IC chip holder 43
And a connecting portion 44 extending from the IC chip holding portion 43 and connected to the circuit board 21. Further, a substantially rectangular IC chip 22 that generates a drive voltage for driving the plate-type piezoelectric actuator 120 is provided at a substantially central portion of the IC chip holding portion 43.

The IC chip 22 is driven by the power supply supplied by the power supply line 50 and the common line 54 for the power supply, and corresponds to each ejection nozzle of the ejection nozzle group based on the drive signal input from the signal line 51. Output line 53
It has a built-in drive circuit that outputs an injection signal. The flexible wiring board 24 includes a power supply line 50, a common line 54, a signal line 51, an output line 53, and a common line 52 along a side edge on the long side corresponding to the two ejection nozzle groups 7a and 7b of the recording head 19, respectively. Has a wiring pattern consisting of symmetric with respect to the longitudinal centerline of the flexible wiring board 24, and the IC chip 22 correspondingly has two sets of drive circuits built therein. In the head connecting portion 42, the end portions of the output line 53 and the common line 52, that is, the terminals 53a and 52a are arranged along both long side edges.

In the connecting portion 44 of the flexible wiring board 24, the other end of the common line 52, each end of the power supply line 50, the common line 54 and the signal line 51 are connected to a plurality of input terminal lines 45, 46 ,. 47 are arranged. The reason why it is divided into a plurality of columns is that the width of each input terminal is made larger than that of the signal line 51 and that the entire flexible wiring board 24 is accommodated within a predetermined width. The flexible wiring board 25 also has a structure similar to that of the flexible wiring board 24 and has an IC chip 23 similar to the IC chip 22 mounted thereon.

The circuit board 21 is composed of an insulating substrate having a normal rigidity, and has one surface on one side, as shown in FIG.
Multiple rows of output terminal lands 61, 62, 63 corresponding to the multiple rows of input terminal lands 45, 46, 47 of the flexible wiring board 24, and multiple rows of input terminal lands 45, 46, 47 of the flexible wiring board 25. A plurality of output terminal land rows 64, 65, 66 corresponding to the above, and a contact 55 (see FIG. 2) connected to the connection portion 80a provided on the wiring board 80 on the carriage on the other surface, the output terminal land row 6
It has a wiring pattern (not shown) that connects the contacts 1, 55, 62, 63, 64, 65, 66. Each terminal land of the input terminal land row 45 of the flexible wiring board 24 is a terminal land of the output terminal land row 61, each terminal land of the input terminal land row 46 is a terminal land of the output terminal land row 62, and an input terminal row. Each terminal land of the land 47 is a terminal land of the output terminal land row 63, each terminal land of the input terminal land row 45 of the flexible wiring board 25 is a terminal land of the output terminal land row 64, and each terminal of the input terminal land row 46. The lands are connected to the terminal lands of the output terminal land row 65, and the respective terminal lands of the input terminal land row 47 are connected to the terminal lands of the output terminal land row 66 one to one. The common line 54 for the power supply of the IC chips 22 and 23 and the common line 52 of the flexible wiring boards 24 and 25 are connected to each other through the terminals of the circuit board 21.

As shown in FIGS. 9 and 13, the terminal land row on the side where the flexible wiring boards 24 and 25 are fixed to the circuit board 21 (that is, the IC chip holding portion 43 side) is extended. Each of the terminal lands 46, 47 and the terminal lands 62, 63, 65, 66 facing each other has a substantially circular shape in a plan view, and the terminal land row 45 on the opposite side and each terminal lands 61 of the terminal land row 61 opposite thereto. The land has a substantially rectangular shape in plan view. Further, the terminal land row 47 closest to the IC chip holding portion 43 and the terminal lands of the terminal land rows 63 and 66 facing the terminal land row 47 are formed to have a larger area than the terminal lands of the other rows. This is because when the flexible wiring boards 24 and 25 and the terminal lands of the circuit board 21 are soldered to each other, the flexible wiring board is bent from the connection portion with the circuit board, arranged in a curved state, or bent during assembly. However, the reason is that the soldering area on the side where peeling is likely to occur is increased to make it difficult to peel off.

The terminal land rows 62, 63 of the circuit board 21,
A through hole 72 penetrating the circuit board 21 is provided for each of the terminal lands 65 and 66, and a conductive material forming each terminal land extends along the inner surface of the through hole 72. The through hole 72 is located deviated from the center with respect to each terminal land.

When the flexible wiring boards 24 and 25 are connected to the circuit board 21, solder H (FIG. 15) is previously attached to the terminal lands of the terminal land rows 61, 62, 63, 64, 65 and 66 of the circuit board 21. Is applied, and the terminal lands of the flexible wiring boards 24 and 25 are made to correspond to the terminal lands of the circuit board 21, and the flexible wiring boards 24 and 25 are heated while being pressed against the circuit board 21 by a heat bar. The applied solder H is melted and the corresponding terminal lands are connected to each other. At this time, the excess solder H escapes to the through hole 72 so that the adjacent terminal lands do not short-circuit due to the protruding solder. Further, a solder resist S is formed on the flexible wiring boards 24 and 25 so as not to cover the respective terminal lands so that the molten solder does not flow out or flow into the adjacent terminal lands. No solder resist is provided on the circuit board 21 over the entire terminal land row. If the through holes are provided on the flexible wiring boards 24, 25 side, the flexible wiring board is thinner than the circuit board 21, so that the melted solder escapes to the outside of the flexible wiring board and adheres to the pressing tool for work. Although there is a possibility of causing trouble or short-circuiting between the terminal lands, as described above, the flexible wiring boards 24, 2
By making the terminal lands of No. 5 closed, the work is facilitated, and the entire solder is efficiently heated and sufficiently melted through the thin flexible wiring board, so that the opposing terminal lands can be reliably connected.

Next, referring to FIG. 10, the recording head 1
The structures of 9 and 20 will be described. The recording head 1
Since both 9 and 20 have substantially the same shape, only the recording head 19 will be described here.
The description of 0 is omitted. FIG. 10 is an exploded perspective view of the recording head 19. As shown in FIG. 10, the recording head 19 is
A plurality of pressure chambers 116, which are formed by extending grooves in a direction orthogonal to the longitudinal direction of the cavity plate 110, are formed on the surface of the cavity plate 110 formed of a laminated structure of metal plates formed in a substantially rectangular shape. Plate 11
They are arranged in two columns in parallel along the longitudinal direction of 0. Then, on the cavity plate 110, the plate-type piezoelectric actuator 120 formed in a substantially rectangular plate shape is
The pressure chambers 116 are bonded so as to close the pressure chambers 116, and the head connecting portion 42 of the flexible wiring board 24 is bonded to the upper portion of the plate-type piezoelectric actuator 120 so as to overlap the plate-type piezoelectric actuator 120. . The two rows of pressure chambers 116 communicate with the two rows of ejection nozzle groups 7a and 7b on the lower surface, respectively, and eject ink downward. Two recording heads are provided with two rows of pressure chambers, respectively, so that ink of four colors is ejected.

FIG. 11 is an exploded perspective view showing a state where the plate type piezoelectric actuator 120 is separated from the cavity plate 110, and FIG. 12 is an exploded perspective view of the plate type piezoelectric actuator 120. 11 and 1
As shown in FIG. 2, the plate-type piezoelectric actuator 120
Is formed in a structure in which ten piezoelectric sheets 121 to 130 are laminated. In addition, each piezoelectric sheet 121 to 130
Among them, the piezoelectric sheets 126, 128, 130 are all formed in the same structure, and the piezoelectric sheets 126, 128, 130 are
On the upper surface of the drive electrode 1 having a narrow width at a position corresponding to each pressure chamber 116 provided in the cavity plate 110.
36 are formed respectively. Further, the end 136a of each drive electrode 136 is connected to each of the piezoelectric sheets 126, 128, 130.
Are formed so as to be exposed to the side surfaces 126a and 126b (similarly to other piezoelectric sheets).

Further, the piezoelectric sheets 123, 124, 12
5, 127, 129 are all formed in the same structure, and a strip-shaped common electrode 135, which is a common electrode for the plurality of pressure chambers 116, is formed on the upper surfaces of the piezoelectric sheets 123, 124, 125, 127, 129. Has been formed. In addition, the end portion 135 a of each common electrode 135 has a piezoelectric sheet 123,
The side surfaces 123a, 12 of 124, 125, 127, 128
3b (similar to other piezoelectric sheets) are formed so as to be exposed.

Further, on the upper surface of the uppermost piezoelectric sheet 121, the surface electrode 1 for each drive electrode 136 is formed.
31 and a surface electrode 132 for the common electrode 135
And are arranged side by side along the side surfaces 121a and 121b of the piezoelectric sheet 121. Further, the piezoelectric sheets 121 to 13 in the plate-type piezoelectric actuator 120
After stacking 0, the side electrodes 133 that electrically connect the drive electrodes 136 and the surface electrodes 131 and the common electrodes 135 and the surface electrodes 132 are electrically connected to the left and right side surfaces orthogonal to the upper surface or the lower surface thereof. Side electrodes 134 to be connected are each formed.

Then, as shown in FIG. 9, the head connecting portion 42 of the flexible wiring board 24 is superposed on the upper surface of the piezoelectric actuator 120 of the recording head 19, and the head connecting portion 4 is attached to each surface electrode 131 of the piezoelectric actuator 120.
The terminals 53a of the two output lines and the terminals 52a of the common lines are soldered to the surface electrodes 132 in a one-to-one correspondence. The flexible wiring board 25 is similarly connected to the piezoelectric actuator 120 of the recording head 20.

As described above, the flexible wiring boards 24 and 25 are independently provided for the respective recording heads 19 and 20,
Since the IC chips 22 and 23 are provided for the respective flexible wiring boards 24 and 25, the common lines 52 are arranged on both long side edges of the flexible wiring boards 24 and 25, respectively.
The surface electrodes 132 corresponding to the common electrodes corresponding to the four rows of the injection nozzle groups of 20 are connected to the common line 52 and the circuit board 2 respectively.
It is possible to connect to the common potential, that is, the ground, through the common line of the one wiring pattern. If the flexible wiring boards 24 and 25 are composed of one insulating substrate and one IC chip is commonly used for four rows of jet nozzle groups, the inner two row jet nozzle groups of the four rows are used. The common line 52 to the circuit board 21 cannot be directly connected to the circuit board 21 and cannot have a sufficient common potential.
By configuring as described above, each recording head 19, 20
It is possible to easily connect each of the surface electrodes 132 to the circuit board and set the common electrode to a sufficient common potential.

Further, as shown in FIGS. 2 and 6, a leaf spring 95 is provided on the surface of the circuit board 21 on which the contact 55 is provided. The leaf spring 95 is in contact with the heat sink 26 and is connected to the ground through the common wire in the wiring pattern on the circuit board 21.

FIG. 14 shows a state in which the recording heads 19 and 20, the flexible wiring boards 24 and 25, and the circuit board 21 are connected as described above, and FIG. 16 shows a state in which they are assembled to the head holder 18. Show. Recording head 1
The head cover 70 is put on the heads 9 and 20 so that the ejection nozzle groups 7a to 7d are exposed through the openings 70b and 70c of the head cover 70, and the heads 9 and 20 are adhesively fixed to the head holding portion 28 of the head holder 18. Circuit board 21
Is fixed to the projections 36 and 37 of the back wall 18b as described above.

At this time, the elastic material 27 made of rubber or resin material is previously bonded and fixed to the elastic material mounting portion 29, and the flexible wiring boards 24 and 25 are I-shaped.
The portion on which the C chip is mounted is arranged along the inclined surface of the elastic material 27, and the recording head 19 is bent at an obtuse angle as a whole while curving in an arc on both sides of the portion.
Circuit board 2 from bottom wall 18a where 20 is located to back wall 18b
Located across 1. Therefore, since a large force does not act on the flexible wiring boards 24 and 25 at the bent portions, the conductive wire on the flexible wiring boards 24 and 25 is not damaged.

The heat sink 16 covers the flexible wiring boards 24 and 25, and the outer peripheral portion thereof is adhesively fixed to the side wall 18d, the heat sink holding wall 40 and the like by an adhesive as described above. At this time, the inner surface of the heat sink 26 abuts the IC chips 22 and 23 to compress the elastic material 27. That is, the elastic material 27 allows the IC chips 22, 2
3 is pressed against the heat sink 26 in a heat conductive manner.
As a result, the IC chips 22 and 23 are attached to the heat sink 26.
It is not necessary to bond it to the
It is possible to effectively release the heat of the IC chips 22 and 23 without generating stress between the C chips 22 and 23 and the heat sink 26. In addition, the heat sink 26
Is connected to the ground via the circuit board 21 by the leaf spring 29, static electricity can also be discharged, and the IC chips 22 and 23 can be prevented from being destroyed by static electricity.

When the heat sink 16 is fixed as described above, the contact 55 of the circuit board 21 is not covered by the heat sink 26 but is exposed to the outside. When the head holder 18 is attached to the carriage 8, the contacts 55 of the circuit board 21 come into contact with the carriage-side connecting portion 80a and are connected to the main body side control board via the wiring board 80 and the flexible wiring board. The terminal land rows 45, 4 of the flexible wiring boards 24, 25 are not provided with the circuit board 21.
It is also possible to expose 6, 47 directly to the outside and bring them into contact with the substrate or the like on the carriage side.

The present invention is not limited to the above embodiment, but various modifications can be made. FIG. 17 is a plan view showing a modified example of the flexible wiring board.
8 is a sectional view taken along the line CC of FIG. FIG. 17
As shown in FIG. 3, the flexible wiring board 150 includes a substantially rectangular IC chip holding portion 151 a and a head connecting portion 15.
1b and a connecting portion 151c between the circuit board 21 and a strip-shaped insulator 151, and a plurality of conductive wires provided on the strip-shaped insulator 151. In addition, the strip-shaped insulator 151
An IC chip 155 that generates a driving voltage for driving the plate-type piezoelectric actuator 120 provided in the recording head is flip-chip mounted on the IC chip holding portion 151a.

The IC chip 155 has the power supply line 172 and the common line 17 for the power supply, as in the above embodiment.
Driven by the power source supplied by
A drive circuit that outputs an ejection signal to the output line 174 corresponding to each ejection nozzle of the ejection nozzle group based on the drive signal input from the No. 5 is incorporated. Flexible wiring board 151
Are symmetrical with respect to the longitudinal centerline of the flexible wiring board so as to respectively correspond to the ejection nozzle groups of two rows of the recording head, the power supply line 172, the common line 173, and the signal line 17
5, output line 174 and common line 1 for that output line
It has a wiring pattern composed of 62 and 165. In this embodiment, similar to the above-described embodiment, the common line 1 is provided along both longitudinal edges of the flexible wiring board 151.
62 is provided, and a common line 165 is provided along the longitudinal centerline of the flexible wiring board.

Common lines 162 and 165, a power line 172, and a common line 173 are provided at a connection portion 151c with the circuit board 21.
Also, each end of the signal line 175 is arranged to form a plurality of input terminal land rows as in the above-described embodiment.
On the flexible wiring board corresponding to the lower side of the IC chip 155, the power supply terminal land 1 connected to the power supply line 172.
70, power terminal land 17 connected to common line 173
1, a terminal land 175a connected to the signal line 175 and a terminal land 174b connected to the output line 174 are provided. As shown in FIG. 18, the terminal lands protruding from the IC chip 155 are brought into contact with them, and the IC chip 155
Are connected and fixed on the flexible wiring board. At this time, the common line 165 passing through the center of the flexible wiring board
Passes under the IC chip 155 but is not connected to the IC chip. Here, the common lines 162, 165, 173
Are mutually connected in the circuit board 21.

At the head connecting portion 151b, the end portion of the output line 174, that is, the terminal land 17 is provided along both side edges in the longitudinal direction.
4a are arranged in rows, and common wires 162, 16 are provided at both ends of the row.
5, the terminal lands 162a and 165a are arranged. The surface electrode 131 for the drive electrode of the piezoelectric actuator 120 of the recording head is connected to the terminal land 174a of the output line 174, and of course, in the above-described embodiment, only the surface electrode 132 at one end of the common electrode is
Although it was connected to the terminal land 162a of the common line 162 at the side edge, in the present embodiment, the surface electrode 132 at the other end of the common electrode is also connected to the terminal land 165a of the central common line 165.

In the above-mentioned embodiment, the common line is connected to the common line 162 from only one end of the common electrode and is connected to the common potential, that is, the ground. However, since the common electrode between the piezoelectric sheets is thin and has a large resistance value, There is a risk that the potential may rise at the portion of the common electrode far from the common line 162, and ink may not be ejected normally. However, with the above configuration, both ends of the common electrode can be connected to the ground, the rise of the potential can be suppressed over the entire common electrode, and normal injection can be performed from all the injection nozzles.

[0047]

As described above in detail, in the flexible wiring board connection structure according to the first aspect of the present invention, the terminal land of the circuit board is formed with the through hole penetrating the circuit board. Since the terminal land of the flexible wiring board facing the hole is closed, it is possible to satisfactorily heat and pressurize the solder that has melted outside the flexible wiring board from the side of the flexible wiring board. Can be efficiently heated and sufficiently melted to reliably connect the opposing terminal lands, and it is possible to prevent the excess portion of the solder from escaping into the through hole and short-circuiting between the adjacent terminal lands.

In addition, in the flexible wiring board connection structure of the invention according to claim 2, in addition to the effect of the invention of claim 1, the through hole is formed at a position not coaxial with the terminal land on the circuit board. Since it is provided, even if the area of the terminal lands is small, excess solder can be poured into the through holes to firmly connect the terminal lands.

According to the flexible wiring board connecting method of the invention of claim 3, the terminal land of the circuit board is
A through hole is formed through the circuit board, and the terminal land of the flexible wiring board facing the through hole is formed in a closed shape, and the terminal land of the flexible wiring board and the terminal land of the circuit board are When heat and pressure are applied from the side opposite to the terminal land of the flexible wiring board with the solder interposed between them, the melted solder does not escape to the outside of the board, and the heating and pressurizing work is performed well. As a result, the entire solder is efficiently heated and sufficiently melted, and the opposing terminal lands can be reliably connected, and the excess portion of the solder escapes to the through hole, causing a short between adjacent terminal lands. Can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an internal structure of an inkjet printer 1.

FIG. 2 is a perspective view of the recording head unit 17 as viewed from the back side of its bottom.

FIG. 3 is a perspective view of the recording head unit 17 as viewed from the back side of its bottom.

FIG. 4 is a side view showing a connection state between a recording head unit 17 and a carriage 8.

FIG. 5 is a plan view of the recording head unit 17 as seen from the upper surface side thereof.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a perspective view of the head holder 18 as viewed from the back side of its bottom.

FIG. 8 is a perspective view of the head holder 18 as viewed from the front side of the upper part thereof.

9 is a plan view showing flexible wiring boards 24 and 25 and recording heads 19 and 20. FIG.

10 is an exploded perspective view of the recording head 19. FIG.

11 is an exploded perspective view showing a state where the plate-type piezoelectric actuator 120 is separated from the cavity plate 110. FIG.

FIG. 12 shows a plate type piezoelectric actuator 1
FIG. 20 is an exploded perspective view of 20.

FIG. 13 is a plan view of the circuit board 21.

FIG. 14 is a perspective view showing a state in which flexible wiring boards 24 and 25 connected to a circuit board 21 are bent.

15 is a sectional view taken along the line BB of FIG.

FIG. 16 shows a head holder 18 including flexible wiring boards 24 and 25, a circuit board 21, and a recording head 1.
It is a perspective view showing the state where 9 and 20 are attached.

FIG. 17 is a plan view showing a modified example of the flexible wiring board.

18 is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

1 Inkjet Printer 2 Case 8 Carriage 10 Platen Roller 11 Guide Rod 12 Guide Member 13 Belts 14c, 14m, 14y, 14b Ink Cartridge 15 Nozzle Surface 16 CR Motor 17 Recording Head Unit 18 Head Holder 19, 20 Recording Head 21 Circuit Board 22 , 23 IC chip 24, 25 Flexible wiring board 26 Heat sink 27 Elastic material 45, 46, 47 Input terminal row 61, 62, 63, 64, 65, 66 Terminal row 80 Wiring board 80a Connection portion 95 Leaf spring H Solder S Solder resist

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5E317 AA24 BB12 CC15 CD32 GG07                       GG16                 5E338 AA02 AA12 BB13 CD32 EE26                       EE31 EE51                 5E344 AA01 AA22 BB04 CC05 CC24                       DD02 DD03 EE21 EE23 EE26

Claims (3)

[Claims] 1. A flexible wiring board having a plurality of conducting wires on a flexible strip-shaped insulator, and a circuit board having a wiring pattern connected to the plurality of conducting wires of the flexible wiring board, wherein the flexible wiring board is provided. In the connection structure of the flexible wiring board, the terminal lands formed on the ends of the conductor on the wiring board and the ends of the wiring pattern on the circuit board are soldered to each other. Is a through hole that penetrates the circuit board and has a shape in which the terminal land of the flexible wiring board facing the through hole is closed, and the terminal land of the flexible wiring board and the terminal land of the circuit board are soldered. The flare is characterized in that the excess portion of the melted solder is connected to the through hole and is released. Connection structure of reluctant wiring board. 2. The connection structure for a flexible wiring board according to claim 1, wherein the through hole is formed at a position which is not coaxial with the terminal land on the circuit board. 3. A flexible wiring board having a plurality of conductors on a flexible strip-shaped insulator, and a circuit board having a wiring pattern connected to the plurality of conductors of the flexible wiring board, the flexible board In the method of connecting a flexible wiring board, the terminal lands formed on the ends of the conductor on the wiring board and the ends of the wiring pattern on the circuit board are soldered to each other. Is forming a through hole penetrating the circuit board, forming a terminal land of the flexible wiring board facing the through hole is closed, the terminal land of the flexible wiring board and the terminal land of the circuit board, They face each other with solder interposed between them, and heat and pressure are applied from the side opposite to the terminal land of the flexible wiring board. In addition, while connecting the terminal lands of the circuit board and the terminal lands of the flexible wiring board with solder melts, a method of connecting a flexible wiring board, characterized in that releasing the excess portion of the solder to the through hole.