JP2004074740A - Liquid jetting head member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jetting head having a circuit board capable of suppressing occurrence of warpage due to thermal stress or the like. <P>SOLUTION: This liquid jetting head member comprises a plurality of nozzle openings 15, a plurality of pressure generating chambers 17 that respectively communicate with the nozzle openings 15 and can contain a liquid, a plurality of piezoelectric members 13 being connected to respective wall members for partitioning the pressure generating chambers 17 and capable of displacing the respective pressure generating chambers 17, and a box body section defining a container room 12 for containing the piezoelectric members 13. A base end section 32 of the circuit board 30 is bonded to the plurality of piezoelectric members 13 and the tip portion 30f thereof is bent so as to reach the external side face of the box body section through a bending region 30f. A plurality of tip conductor sections 37 are formed in roughly parallel to each other on the tip portion 33 of the circuit board 30. The tip conductor sections 37 are connected to conductive pads 41 provided on the external side face of the box body section with solder therebetween. The tip conductor sections 37a at both ends are formed to be thinner than the other tip conductor sections 37b. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid ejecting head member that ejects liquid from a nozzle opening based on an electric signal, for example, relates to a recording head that performs recording by ejecting ink droplets from a nozzle opening based on an electric signal. The present invention relates to a liquid jet head having excellent supply reliability.
[0002]
[Prior art]
The recording head of the ink jet recording apparatus ejects ink droplets by supplying an electric signal to a piezoelectric member in the recording head. The supply of the electric signal to the piezoelectric member is performed via a flexible cable or a plate-like circuit board.
[0003]
When a plate-like circuit board is used, its handling is easy due to its rigidity, and a more accurate manufacturing process can be realized.
[0004]
FIG. 5 shows a configuration of a conventional plate-like circuit board. The plate-like circuit board 100 shown in FIG. 5 is formed from a plate material in which a metal having high solder wettability, for example, tin, is adhered in a foil shape to a base made of a heat-resistant electrical insulating material, for example, a polyimide film. I have.
[0005]
As shown in FIG. 5, a window 101 for mounting a semiconductor device for control is formed in the substrate 100. The window 101 can be formed by, for example, a press or the like.
[0006]
A desired conductive pattern (not shown) is formed by etching so as to sandwich the window 101, and is exposed as a connection line 106 at a base end portion 102 connected to the piezoelectric member, and is also connected to the connection board by soldering. The portion 103 is also exposed as a connection line 107. Other portions of the conductive pattern are covered with a cover coat layer 104.
[0007]
For reasons of wiring design, the connection lines 107 on both left and right ends are formed thick to withstand a large current supply.
[0008]
[Problems to be solved by the invention]
However, the above-described plate-shaped circuit board 100 has a problem in that, when it is soldered to the connection board, “warpage” occurs due to thermal stress on both left and right sides of the distal end portion 103.
[0009]
The present inventors have conducted intensive studies on the above problem, and have found that the formation of the thick connection lines 107 on both left and right sides greatly affects the occurrence of “warpage”.
[0010]
Further, the above-described plate-like circuit board 100 is often used in a state in which the distal end portion 103 is bent (see the circuit board 30 in FIG. 1). In such a case, the fact that the connection line 107 is thick is not preferable because it increases the bending difficulty.
[0011]
Further, in such a case, after the solder connection is performed, “bending” occurs in the bent tip portion 103 to return to the original state due to the strong “stiffness” of the plate-shaped circuit board 100. May be. The extent to which this phenomenon occurs is greater when the connection line 107 is thick.
[0012]
As a technique for reducing the bending difficulty, the present inventor has known the invention disclosed in Japanese Patent Application Laid-Open No. 4-144186. However, when slits (holes) are formed at both left and right ends of the substrate as disclosed in the publication, the influence of “warpage” due to thermal stress on both right and left ends may increase.
[0013]
Further, in order to increase the reliability of joining by soldering when performing solder connection, it has been studied to increase the temperature of the tool or to increase the load applied to the circuit board by the tool. However, increasing the temperature of the tool or increasing the load applied by the tool can cause the tool to deform, in which case the solder connection is rather uncertain.
[0014]
The present invention has been made in view of such circumstances, and provides a liquid ejecting head having a circuit board capable of suppressing occurrence of “warpage” due to thermal stress or the like and making electric connection more reliable. With the goal. Still another object of the present invention is to provide a liquid ejecting head having a circuit board in which the occurrence of “warpage” due to thermal stress or the like is suppressed to make electrical connection more reliable and bending difficulty is reduced. I do.
[0015]
[Means for Solving the Problems]
The present invention is connected to a plurality of nozzle openings, a plurality of pressure generation chambers respectively communicating with the respective nozzle openings and capable of containing a liquid, and a wall member for partitioning each pressure generation chamber, and deforming each pressure generation chamber. A plurality of piezoelectric members for ejecting liquid droplets from the respective nozzle openings, a box body defining a housing chamber for housing the piezoelectric members, and a circuit board adhered to the plurality of piezoelectric members at a base end portion, The front end of the circuit board is bent so as to reach on the outer surface of the box body through the bent area, and a plurality of front end conductors are formed substantially parallel to the front end of the circuit board. The tip wire portion of the circuit board is connected to a conductor member provided on the outer surface of the box portion via solder, and among the plurality of tip wire portions of the circuit board, the arrangement of the tip wire portions Both ends in the direction (for example, the direction perpendicular to each tip conductor) The tip conductor portion which is a liquid jet head member, characterized in that it is formed narrower than the other tip conductor portion.
[0016]
According to the present invention, since the tip conductors at both ends in the direction perpendicular to each tip conductor are formed thinner than the other tip conductors, the tip conductor and the conductor member are soldered. The escape of heat during conduction is significantly reduced, and soldering can be performed quickly. As a result, the generation time of the thermal stress is reduced, so that the occurrence of “warpage” in the circuit board is suppressed, and the circuit board is securely fixed to a predetermined position. That is, the reliability of the electrical connection is increased, and the reliability of the supply of the electric signal to the piezoelectric member is excellent.
[0017]
Preferably, the distal end wire portions at both ends formed thinly function as one signal terminal at each end. Preferably, there are a plurality of thinly formed distal end lead wires at each end. For example, the thinned end conductors at both ends are obtained by dividing one power supply line at each end. Thus, the power supply line mounted on the circuit board works extremely well.
[0018]
Preferably, the conductor member is provided independently for each of the leading conductors of the circuit board. In this case, since the escape of heat from the conductor member side is also suppressed, the soldering can be performed more quickly.
[0019]
Preferably, a plurality of through-holes are formed in the bent region of the circuit board so as not to interfere with the leading conductor. Thereby, the difficulty of bending the circuit board is reduced. More preferably, each through-hole is formed substantially at the center of two adjacent tip conductor portions. In this case, thermal stress and the like can be received with a substantially equal balance. More preferably, each through-hole is formed substantially at the center in the extending direction of the distal end wire portion, that is, not formed at the joint portion by solder. In this case, the problem that the solder melted by the heat protrudes from the through hole and adheres to the jig or the like can be prevented.
[0020]
In addition, the present invention is connected to a plurality of nozzle openings, a plurality of pressure generating chambers respectively communicating with the respective nozzle openings and capable of containing a liquid, and a wall member for partitioning the pressure generating chambers. A plurality of piezoelectric members that are deformed to discharge liquid droplets from each nozzle opening, a box body that defines a housing chamber that houses the piezoelectric members, and a circuit board that is bonded to the plurality of piezoelectric members at a base end. The front end of the circuit board is bent so as to reach the outer surface of the box body via the bent area, and a plurality of front end conductors are formed substantially parallel to the front end of the circuit board. A plurality of through-holes are formed between the tip conductors in the central region in the arrangement direction of the tip conductors, among the plurality of tip conductors of the circuit board, so as not to interfere with the tip conductors. Liquid jet head member characterized by the following: A.
[0021]
According to the present invention, since a plurality of through-holes are formed between the tip conductors only in the central region in the arrangement direction of the tip conductors so as not to interfere with the tip conductors, the circuit board is bent. While the difficulty is reduced, the problem of "warpage" due to thermal stress does not occur.
[0022]
According to another aspect of the invention, there is provided a liquid ejecting apparatus including: a liquid ejecting head member having any one of the above features; and a control unit that supplies an electric signal to a piezoelectric member of the liquid ejecting head member.
[0023]
Further, the present invention is a conductor member used together with a liquid ejecting head member having any one of the above features, provided on the outer surface of the box body portion, for each of the leading wire portions of the circuit board. A conductive member, for example, a conductive pad, which is provided independently and is connected to each of the leading end portions of the circuit board via solder.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
FIG. 1 is a diagram showing an ink jet recording head 10 which is an example of a liquid jet head member. The recording head 10 includes a base 11, a piezoelectric vibrator 13 (piezoelectric member) that is oscillated in a housing chamber 12 of the base 11, and a flow path unit 14 that is fixed to the lower surface of the base 11. And
[0026]
The flow path unit 14 includes a nozzle plate 16 in which a plurality of nozzle openings 15 are formed in a row, a thin diaphragm 21 which is elastically deformed, and a liquid-tight diaphragm sandwiched between the nozzle plate 16 and the diaphragm 21. And a flow path forming plate 20 fixed to the base plate. The flow path forming plate 20 includes a plurality of pressure generating chambers 17 communicating with the respective nozzle openings 15, an ink chamber 18 (liquid storage chamber) receiving supply of ink from an ink cartridge, and a plurality of A space corresponding to an ink supply path 19 that supplies ink to the pressure generating chamber 17 is formed. For example, separate ink chambers 18 and rows of nozzle openings 15 are provided for each of the six types of ink colors.
[0027]
The piezoelectric vibrator 13 is attached to a support substrate 22, and the support substrate 22 is fixed in the accommodation room 12 of the base 11 so as to be vibrably accommodated in the accommodation room 12. The lower end of the piezoelectric vibrator 13 is bonded to the island 21 a of the vibration plate 21 of the flow path unit 14. The upper surface side of the accommodation room 12 of the base 11 is covered by an upper closing plate 40. That is, a box body is formed by the base 11 and the upper closing plate 40.
[0028]
In FIG. 1, reference numeral 30 denotes a circuit board for sending a drive signal to the piezoelectric vibrator 13, and reference numeral 25 denotes an ink supply hole for supplying ink which communicates with the ink chamber 18. The ink chamber 18 has a function of communicating the ink supply paths 19 in common and a function of temporarily storing ink.
[0029]
The base end of the circuit board 30 and the piezoelectric vibrator 13 are joined by soldering of a solder 27. Further, the upper end portion (tip portion) of the circuit board 30 protrudes from the upper closing plate 40 and then bends along the outer surface of the upper closing plate 40 to form the conductor pads 41 (formed on the upper closing plate 40). (See FIG. 3).
[0030]
FIG. 2 is a schematic front view of the circuit board 30 before being bent. The circuit board 30 is formed of a plate material in which a metal having high solder wettability, for example, tin, is adhered in a foil shape to a base made of a heat-resistant electrical insulating material, for example, a polyimide film.
[0031]
As shown in FIG. 2, a window 31 for mounting a semiconductor device for control is formed in the circuit board 30. The window 31 can be formed by, for example, a press or the like.
[0032]
A desired conductive pattern (not shown) is formed by etching so as to sandwich the window 31, and is exposed as a connection line 36 at a base end portion 32 connected to the piezoelectric vibrator 13, and a conductive pad 41 (FIG. 3). ) Is also exposed as a connection wire 37 (tip wire portion). Other portions of the conductive pattern are covered with a cover coat layer 34.
[0033]
As shown in FIG. 2, a plurality of connection lines 37 (37a, 37b) are formed substantially in parallel. Out of the plurality of connection lines 37, the connection lines 37a on the left and right ends (the direction of arrangement of the connection lines 37 = on both ends in the direction perpendicular to the connection lines 37) are formed thinner than the other connection lines 37b. I have. In this case, the number of connection lines 37a formed thin is three on each side. The ratio of the line width of the connection line 37a to the line width of the connection line 37b is 2: 1.
[0034]
Further, as shown in FIG. 2, a plurality of through holes 39 are formed in the bent region 30 f of the circuit board 30 so as not to interfere with the connection lines 37. In the present embodiment, among the plurality of connection lines 37 of the circuit board 30, only a central region where the connection lines 37b are arranged is formed with a plurality of through holes 39 so as not to interfere with the connection lines 37b. I have. Each through hole 39 is formed substantially at the center of two adjacent connection lines 37b.
[0035]
According to the circuit board as shown in FIG. 2, the bending operation via the bending area 30f is easy due to the presence of the through holes 39.
[0036]
In addition, since the connection lines 37a on both left and right sides are formed to be thin, the escape of heat when soldering the connection lines 37a to the conductor pads 41 is significantly reduced, so that the soldering can be performed quickly. As a result, the generation time of the thermal stress is reduced, so that the occurrence of “warpage” in the circuit board 30 is suppressed, and the circuit board 30 is securely fixed at a predetermined position. That is, the reliability of the electrical connection is increased, and the reliability of the supply of the electric signal to the piezoelectric vibrator 13 is excellent.
[0037]
Even after the solder connection has been made, even if the “stiffness” of the circuit board 30 is strong, the connection lines 37a on both left and right sides are formed thin, so that the bent front end portion is formed. The effect of generating "warping" when returning is effectively suppressed.
[0038]
Furthermore, since each through-hole 39 is formed substantially at the center of two adjacent connection lines 37b, it is possible to receive thermal stress and the like in a substantially even balance, and to effectively eliminate adverse effects caused by thermal stress. be able to.
[0039]
Further, the through holes 39 are not provided on both left and right sides of the circuit board 30. Further, since both ends outside the slit are connected by a plurality of connection lines, an increase in the influence of “warping” due to thermal stress on the left and right ends is also avoided.
FIG. 3 is a diagram showing an example of the arrangement of the conductor pads 41 formed on the outer surface of the upper closing plate 40. The conductor pads 41 of FIG. 3 are provided independently for each of the connection lines 37a of the circuit board 30. In this case, since the escape of heat from the conductor pad 41 side is also suppressed, the soldering between the connection line 37a and the conductor pad 41 can be performed more quickly. As a result, the occurrence of “warpage” in the circuit board 30 is suppressed.
[0040]
In the recording head 10, for example, ink is ejected as follows. That is, first, when the piezoelectric vibrator 13 receives charge and contracts, the pressure generating chamber 17 expands, and the internal pressure decreases. As a result, the meniscus formed in the nozzle opening 15 is slightly drawn toward the pressure generating chamber 17, and the ink in the ink chamber 18 is supplied to the pressure generating chamber 17 through the ink supply path 19.
[0041]
Subsequently, when the electric charge of the piezoelectric vibrator 13 is discharged after a lapse of a predetermined time and the piezoelectric vibrator 13 returns to the original state, the pressure generating chamber 17 contracts and the internal pressure increases. Thus, the ink in the pressure generating chamber 17 is compressed and ejected from the nozzle opening 15 as an ink droplet.
[0042]
As shown in FIG. 4, the above-described inkjet recording head 10 is combined with a control unit 50 for supplying an electric signal to the piezoelectric vibrator 13 which is a piezoelectric member via the conductor pad 41, The inkjet recording device 40 can be configured. In the case of FIG. 4, the inkjet recording head 10a for black ink and the inkjet recording head 10b for color ink are arranged in parallel, and the control unit 50 controls each piezoelectric vibrator 13 corresponding to each nozzle independently. It is supposed to.
[0043]
Although the above description has been made with respect to an ink jet recording head, the present invention is broadly applied to liquid ejecting heads in general. As an example of the liquid, in addition to ink, glue, nail polish, liquid metal for forming a circuit, or the like may be used. Further, the present invention can be applied to a head for manufacturing a color filter in a display such as a liquid crystal.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an embodiment of an ink jet recording head according to the present invention.
FIG. 2 is a schematic front view showing the circuit board of FIG.
FIG. 3 is a diagram illustrating an example of the arrangement of conductive pads on an upper closing plate of FIG. 1;
FIG. 4 is a schematic diagram of an ink jet recording apparatus.
FIG. 5 is a schematic front view showing a conventional plate-like circuit board.
[Explanation of symbols]
10, 10a, 10b Recording head 11 Base 12 Housing chamber 13 Piezoelectric vibrator 14 Flow path unit 15 Nozzle opening 16 Nozzle plate 17 Pressure generation chamber 18 Ink chamber 19 Ink supply path 20 Flow path forming plate 21 Vibrating plate 21a Island portion 22 Support substrate 25 Ink supply holes 27, 28 Solder 30 Circuit board 31 Window 32 Base end 33 Top end 34 Cover coat layer 36 Connection lines 37, 37a, 37b Connection line 40 Upper closing plate 41 Conductor pad 50 Control unit 60 Ink jet recording device

Claims (10)

A plurality of nozzle openings,
A plurality of pressure generating chambers that can communicate with each of the nozzle openings and can accommodate the liquid,
A plurality of piezoelectric members connected to a wall member that divides each pressure generation chamber and deforming each pressure generation chamber to discharge a liquid droplet from each nozzle opening;
A box body defining a housing chamber for housing the piezoelectric member,
A circuit board adhered to the plurality of piezoelectric members at a base end,
With
The front end of the circuit board is bent so as to reach on the outer surface of the box body via the bending area,
At the tip of the circuit board, a plurality of tip conductors are formed substantially in parallel,
The leading wire portion of the circuit board is connected to a conductor member provided on the outer surface of the box body portion via solder,
A liquid ejecting head member, wherein, among the plurality of tip conductor portions of the circuit board, the tip conductor portions at both ends in the arrangement direction of the tip conductor portions are formed thinner than the other tip conductor portions. 2. The liquid ejecting head member according to claim 1, wherein the thinned leading end portions function as one signal terminal at each end. The liquid ejecting head member according to claim 1, wherein a plurality of thin end lead wire portions are present at each end. The liquid ejecting head member according to any one of claims 1 to 3, wherein the conductor member is provided independently for each of the leading end portions of the circuit board. The liquid ejecting head member according to any one of claims 1 to 4, wherein a plurality of through holes are formed in the bent region of the circuit board so as not to interfere with the leading wire portion. The liquid ejecting head member according to claim 5, wherein each through hole is formed substantially at the center of two adjacent leading end wire portions. The liquid ejecting head member according to claim 5, wherein each through hole is formed substantially at a center in a direction in which the leading end wire extends. A plurality of through-holes are formed between the tip conductors in the central region in the arrangement direction of the tip conductors, among the plurality of tip conductors of the circuit board, so as not to interfere with the tip conductors. The liquid jet head member according to any one of claims 1 to 7, wherein: A liquid jet head member according to claim 1,
A control unit for supplying an electric signal to the piezoelectric member of the liquid ejecting head member;
A liquid ejecting apparatus comprising: A conductor member used together with the liquid jet head member according to claim 1,
It is provided on the outer surface of the box part,
Provided independently for each of the leading wire portions of the circuit board,
A conductor member connected to each of the leading conductors of a circuit board via solder.

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