JPH0699596A - Device for connecting conductors to drive means for print head - Google Patents

Abstract

PURPOSE:To ensure the electrical connection of the piezoelectric element of a print head with an external part and to facilitate connecting. CONSTITUTION:Between a pair of poles of a support frame 12 of a print mechanism for driving a print wire, the external electrode of a piezoelectric element 10 and the joint 33 of a wiring board for printing is electrically connected by bending one end of the flexible wiring board, thereby holding it between the base end of the laminated type piezoelectric element 10 and the temperature compensator 13 of its rear end 12c. A pair of connecting metal lines 37 are erected on an electrically-insulated, elastic holder 36 attached to the rear end of the support frame 12, and the joint 34 of the other end of the wiring board and the connecting metal lines 37 are joined together with solder 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a print head device in which a print wire is driven in and out by a print mechanism having a drive means that expands and contracts or vibrates when a voltage is applied. It relates to the structure of electrical conductor connections for transmitting electrical signals to the means.

[0002]

2. Description of the Related Art As a drive means for a print wire in a dot impact print head, piezoelectric ceramics are laminated as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-119276. Some use a piezoelectric element (electrostrictive element) formed by adhesion. That is, the lower end of the piezoelectric element is supported by a support frame that is substantially U-shaped in side view, and a printing mechanism using a spring is provided between the movable element at the tip of the piezoelectric element and one side of the support frame,
By fixing the base end of the printing wire to the tip of the arm attached to this printing mechanism and applying a voltage to the piezoelectric element, the piezoelectric device expands and contracts in the stacking direction of the piezoelectric ceramics. It enlarges and moves the print wire back and forth toward the paper.

In the prior art, in order to apply a voltage to the piezoelectric element from the outside, a middle portion of a copper wire lead wire is fixed to the base end portion of the support frame, and one end of this lead wire is attached to the piezoelectric element. A method was adopted in which it was soldered to the external electrode part formed on, the other end of this lead wire was pulled out from the cover body at the rear of the print head, and soldered to the printed wiring board that was attached to the outer surface of the cover body. .

By the way, since the supporting frame vibrates due to the expansion and contraction drive of the piezoelectric element, the lead wire also vibrates, and if the lead wire is a thin copper wire, the rigidity is small, and in particular, the middle portion of the lead wire. As described above, since both ends of the metal rod-shaped lead wire are soldered, the risk of disconnection of the lead wire is increased, and the lead wire is inadvertently bent during the connection work such as the soldering. There was a problem of poor workability. On the contrary, if the thickness of the lead wire is increased, the lead wire is not bent during the manual connection work, but it is difficult to form the curve, and it takes time to guide the lead wire to a predetermined position.

Such a problem could occur even when an electromagnetic solenoid is used as the driving means.
The present invention provides a device for connecting a conductor to a driving means, which solves the above-mentioned problems with respect to the connection of the conductor to the driving means such as the piezoelectric element, has high working efficiency, and is less likely to be disconnected. The purpose is to do.

[0006]

In order to achieve the above object, the present invention comprises a driving means for driving a printing wire and a conductor covered with an electric insulating layer inside a cover body of a print head. A flexible printed wiring board, and a print head provided with a circuit board on the outside of the cover body, while connecting one end of the conductor in the printed wiring board to an external electrode in the driving means, The other end of the conductor is connected to a metal connection line connected to the circuit board, and a holder for supporting the base of the metal connection line is formed of an elastic member, or the holder of the driving means is formed through an elastic member. It is fixed to the support frame.

[0007]

EXAMPLE Next, an example in which the present invention is embodied will be described. The basic structure of the print head of this example is, as shown in FIG. 1, a head body 1 having a substantially circular shape in front view and a cover body. 2 and a plurality of printing units 3 radially arranged with respect to the head main body 1 in a space surrounded by the two. In this embodiment, the head body 1 and the cover body 2
Is made of aluminum alloy or iron.

A plurality of (24 in the embodiment) printing units 3 are radially arranged via a metallic ring-shaped support 4 which is attached to the back side of the base 1a of the head body 1, and the base of the head body 1 is arranged. Hollow cylindrical nose portion 8 protruding from 1a to the front
An appropriate number of guide plates 9 for guiding the printing wires 7 in each printing unit 3 are provided inside, and the tip of each printing wire 7 is configured to project and retract from the tip of the nose portion 8.

Each printing unit 3 is mounted on the piezoelectric element 10 having a longitudinal length and a front end of the piezoelectric element 10, and a printing mechanism 11 for enlarging the expansion / contraction motion of the piezoelectric element 10 and transmitting it to the printing wire 7. And the printing mechanism 11 and the piezoelectric element 1
In order to support 0, it is composed of a support frame 12 extending rearward from the back surface of the head body 1. Piezoelectric element 1
In No. 0, a large number of rectangular piezoelectric ceramics each having a thickness of about 100 μm are laminated and adhered so that internal electrodes are interposed therebetween. Of the exposed portion where the internal electrodes are exposed on one side surface of the piezoelectric element 10, an electrically insulating material is applied to every other layer of the piezoelectric ceramic, and a conductor is applied to the upper surface from one longitudinal end (tip) of the piezoelectric element. By coating and forming up to the end (rear end), the external electrode 10a is formed on the rear end surface (lower surface) of the piezoelectric element 10 in the embodiment. Therefore,
On the one side surface, the internal electrodes are provided on alternate layers of piezoelectric ceramics not coated with the electrical insulating material.
It will be electrically connected to 0a. In the same manner, on the other side surface of the piezoelectric element 10, an internal electrode exposed by shifting one layer from the internal electrode on the one side surface is coated with an electric insulating material as described above, and a conductor is provided on the upper surface of the internal surface of the piezoelectric element. Is applied and formed from one end (tip) to the other end (rear end), and the other external electrode 10b is formed on the rear end surface (lower surface) adjacent to the one external electrode 10a. Therefore, also on the one side surface, the alternate internal electrodes of the piezoelectric ceramics not coated with the electrical insulating material are the other external electrodes 10b.
Will be electrically connected to.

A conductor exposed at one end of a printed wiring board 30, which will be described later, is electrically connected to the pair of external electrodes 10a and 10b, and the printed wiring board 30 is sandwiched and placed on the temperature compensator 13. Fix with an adhesive. A support frame 12 made of a material having a small linear expansion coefficient, such as iron or nickel alloy (Invar alloy), surrounds the piezoelectric element 10 on both sides in the longitudinal direction and the rear end portion thereof. It is integrally formed in a U shape with the end portion 12c. The sub-column portion 12b may be fixed to the rear end portion 12c by brazing.

When charged by applying a voltage, the piezoelectric element 1
0 expands in the stacking direction (longitudinal direction) and contracts when discharged, and the piezoelectric element 10 contracts due to temperature rise. Therefore, the temperature compensator 13 having a positive temperature expansion characteristic that corrects for this, It is inserted between the rear end portion 12c of the support frame 12 and the rear end of the piezoelectric element 10 and fixed by an adhesive. In this embodiment, the temperature compensator 13 serves as a support portion that supports the rear end of the piezoelectric element 10, but the rear end portion 12c of the support frame 12 may be used as the support portion.

The printing mechanism 11 has an arm 14 which is formed by brazing the base of the printing wire 7 to the tip thereof and which has a substantially triangular shape in a side view.
And a plate-shaped first leaf spring and a second leaf spring extending in parallel rearward in the longitudinal direction of the main strut portion 12a, and a rigid connecting portion that connects the tip ends of both leaf springs to each other in a side view substantially "Π". It is composed of a character-shaped spring body 15 and a four-node link mechanism member 19 described later, and the connecting portion is fitted and fixed to the base end portion of the arm 14 by brazing or the like. The base end of the first leaf spring is brazed and fixed to the side surface of the main strut portion 12a, while the second end
The base end portion of the leaf spring is fixed to the movable element 18 that contacts the front end surface of the piezoelectric element 10 in a pressed state by brazing or the like.

A four-node link mechanism member 19 made of an elastic material such as a spring plate is disposed so as to straddle the other side of the mover 18 and the sub-column part 12b. A hole 17 having a substantially H-shaped side view is formed in the wide side plate portion of the hole 1.
When the piezoelectric element 10 expands and contracts when a voltage is applied, the left and right wide side plate portions are fixed to the front and back side surfaces of the sub strut portion 12b and the front and back side surfaces of the movable element 18 by spot welding (also possible by brazing). The left and right wide side plates of the four-bar linkage mechanism member 19 are elastically deformed into a parallelogram shape in side view so that the mover 18 can move in parallel along the longitudinal direction of the position-fixed sub-column 12b. It is a thing.

In this way, if the mover 18 is configured to move in parallel along the longitudinal direction of the sub strut portion 12b, in other words, linearly in the longitudinal direction of the piezoelectric element 10, the laminated bonding of piezoelectric ceramics is performed. Bending force does not act on the surface, and the laminated portion and the adhesive surface do not peel off accidentally. Then, brazing or screws (not shown), laser beam, with the front surface of the main support portion 12a of each of the printing units 3 radially arranged on the ring-shaped support body 4 aligned with the back surface of the support body 4, laser beam Fix by welding. Further, a plate-like vibration-proof material 24 made of a vibration-proof rubber is interposed between the support body 4 and the base portion 1a of the head body 1 and screwed with screws.

A metal ring-shaped reinforcing member 28 is fixed to the rear end surface of the support frame 12 of the printing unit 3 arranged in the radial direction by laser beam welding or the like to reduce the deformation of each support frame 12 during the printing operation. Is configured to. In this configuration, in a normal printing operation, when the piezoelectric element 10 extends along the longitudinal direction by the application of voltage, the center of rotation of the first leaf spring fixed to the main strut portion 12a is a substantially midway portion in the longitudinal direction. So that the spring body 15
Is oscillated and displaced, the displacement amount is enlarged by the arm 14 via the connecting portion, and the printing wire 7 is driven so as to protrude from the nose portion 8.

Then, the piezoelectric element 10 in each of the printing units 3 is electrically connected to the external electrodes 10a and 10b of the piezoelectric element 10 so that the piezoelectric element 10 operates at a predetermined timing.
In order to transmit the drive voltage signal from the printer controller,
A flexible printed wiring board 30 for electrically connecting to the printed circuit board 29 on the outer surface of the bottom plate portion 2a of the cover body 2.
And a holder 36 that elastically supports the support frame 12.
And a pair of metal connecting wires 37 and 27 which are projected.

In the printed wiring board 30, a pair of lead portions 32, 32 made of a good electric conductor (conductor) such as copper foil is formed on one surface of an electrically insulating film substrate 31, and the lead portion 3 is formed.
Both ends of 2, 2 are exposed so as to form the connecting portions 33, 34, and the remaining portions are covered with the electric insulating material layer 35, which has flexibility. This printed wiring board 30 is generally
It is called a flexible printed wiring board (FPC) or a flexible flat cable.

The first of the printed wiring board 30 and the holder 36
Examples are shown in FIGS. That is, the film substrate 31
Is bent into a substantially U shape (see FIG. 4), and the bent one end 3
A foot portion 31b extending vertically from the portion 1a and the other bent end portion 31
The left and right symmetrical lead portions 32, 32 are formed over c, and the external terminals 10a, 1 of the piezoelectric element 10 are connected to the pair of connection portions 33, 33 exposed at the bent one end portion 31a.
It is formed so that 0b faces each other.

The holder 36, which is made of an elastic body such as a vibration-proof rubber or urethane foam resin, is connected to the pair of metal connecting wires 3.
7 and 37 are embedded in the base ends of the metal wires 37, 37, and the metal connecting wires 37, 37 are connected to the respective metal connecting wires 37, 37 in a ring shape at the other end.
4 is fitted and the respective connecting portions 34 and the metallic connecting wires 37 are electrically connected in advance by solder 38. Then, the foot portion 31b and the other bent end portion 31c of the film substrate 31
The back surface of the holder 3 is adhered to the side surface of the holder 36, and the holder 3
6 is adhered to the rear end portion 12c of the support frame 12 (see FIG. 4).
reference). Next, the connecting portions 33, 33 and the external terminals 10a, 10b of the piezoelectric element 10 are connected by an adhesive agent (not shown) having conductivity.

As shown in FIG. 5, the holder 36 is formed of an electrically insulating synthetic resin, and the connecting portion between the holder 36 and the rear end portion 12c of the support frame 12 has a vibration-proof plate shape. The elastic member 39 such as the above may be inserted. Further, as shown in FIGS. 6 and 7 as a third embodiment, the holder 40 is composed of an electrically insulating base 40a and a lid 40b, and the back surface of the lid 40b is made of urethane foam resin or anti-vibration rubber. While being fixedly adhered to the rear end portion 12c of the support frame 12 via the elastic member 41 such as
Conductive portions 42, 42 are formed by embedding, stretching or coating on the surface of 0a. The conductive parts 42, 42 are made to face the base ends of the respective metal connection wires 37, 37 so as to be in electrical contact with each other (can be embedded), and the other end connection parts 34 of the printed wiring board 30. The metal connection lines 37, 37 and the printed wiring board 30 are pressed and fixed from above by the lid 40b so that they are electrically contacted with each other. At this time, the locking claw portion 43 protruding to the lid 40b is fitted and locked in the hole-shaped locking portion 44 of the base 40a.

FIG. 8 is a modification of the third embodiment, in which conductive parts 42, 42 are provided on the back surface side of the lid 40b of the holder 40, and the other points are substantially the same as those of the third embodiment. Is. Further, in these embodiments, the external terminal portion of the piezoelectric element 10 to be connected to the one end connection portion of the printed wiring board 30 may be formed on the side surface of the piezoelectric element 10 instead of the lower surface.

The metal connecting wires 37, 37 connected as in the above-mentioned respective embodiments are cut out from the holes of the electrically insulating spacer 45 through the holes of the bottom plate 2a of the cover body 2 in the printed circuit board 29. The printed circuit board 2 facing the groove or hole
Each of the metal connecting wires 3 is connected to a power feeding path (not shown) formed on the wide surface of the wide surface of 9 opposite to the side where the spacer 45 is attached.
Solder the tips of 7, 37.

With the above structure, even if the support frame 12 vibrates when the piezoelectric element 10 is driven at a predetermined driving frequency (for example, 4 kHz), the printed wiring board 30, the holder 36 or 40, and the metal connecting wire 37 are formed. , 37 to prevent the resonance frequency of the mass / spring system from resonating with the drive frequency of the piezoelectric element, for example, set the resonance frequency of the mass / spring system to 1.4 times or more the drive frequency of the piezoelectric element. For example, the amplitude in the mass / spring system is significantly reduced, and the solder at the connecting portions 33 and 34 of the printed wiring board 30 may be removed, the pattern of the printed wiring board 30 may be broken, and the metal connecting wires 37 and 37 may be broken. Accidents can be prevented.

Needless to say, the present invention is also applicable to a drive means using an electromagnetic solenoid.

[0025]

As described above, according to the present invention, the drive means for driving the print wire and the conductor covered with the electrically insulating layer are provided inside the cover body of the print head. In a print head having a flexible printed wiring board and a circuit board on the outside of the cover body, a printed wiring board for applying a voltage to the external electrodes of the driving means is provided on the electrically insulating layer. Since the printed wiring board is configured to have flexibility by being covered with a conductor, the printed wiring board can be easily bent in the thickness direction and the deformation work can be easily performed.

On the other hand, the other end of the conductor is connected to the metal connecting wire connected to the circuit board, and the holder for supporting the base portion of the metal connecting wire is formed of an elastic member or via an elastic member. Is fixed to the support frame of the drive means, even if the support frame vibrates due to the operation of the drive means, the vibration isolation effect due to the elasticity of the holder itself or the vibration isolation effect due to the elastic member supporting the holder frame. At, the amplitude of the printed wiring board and the metal connection line is reduced. Therefore, the connection part between the printed wiring board and the driving means or the solder part at the connection portion between the printed wiring board and the metal connection line may be dislocated, or the electrical connection failure such as the disconnection of the conductor pattern portion of the printed wiring board itself may occur. The effect is that it can be prevented.

Further, even if the thickness of the metal connecting wire is increased, there is an effect that there is no risk of breakage due to the reduction of the vibration and that the work of connecting to the circuit board becomes easy.

[Brief description of drawings]

FIG. 1 is a side sectional view of a print head.

FIG. 2 is a side view of a printing unit.

FIG. 3 is a perspective view of a connecting portion of a piezoelectric element, a printed wiring board, and a metal connecting wire.

FIG. 4 is an enlarged sectional view taken along the line IV-IV in FIG.

FIG. 5 is a cross-sectional view of essential parts of a second embodiment.

FIG. 6 is a perspective view showing a connecting portion of a piezoelectric element, a printed wiring board and a metal connecting wire of a third embodiment.

FIG. 7 is a cross-sectional view of essential parts in a third embodiment.

FIG. 8 is a sectional view of an essential part showing a modified example of the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head body 2 Cover body 3 Printing unit 4 Support body 7 Printing wire 8 Nose part 10 Piezoelectric elements 10a, 10b External electrodes 12 Support frame 12c Rear end part 13 Temperature compensator 29 Printed circuit board 30 Printed wiring board 31 Film board 32 Lead Part 33, 34 Connection part 36, 40 Holder 37 Metal connection wire 39, 41 Elastic member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H01R 9/09 Z 6901-5E 9113-2C B41J 29/00 D 9113-2C C

Claims (1)

[Claims] 1. A drive means for driving a print wire and a flexible printed wiring board made of a conductor covered with an electric insulating layer are arranged inside a cover body of a print head. In a print head including a circuit board on the outside of a cover body, one end of a conductor in the printed wiring board is connected to an external electrode of the driving means, and the conductor is connected to a metal connection line connected to the circuit board. A drive for a print head, characterized in that a holder for supporting the base of the metal connecting wire is formed of an elastic member or is fixed to a supporting frame of the driving means via the elastic member. Device for connecting conductors to means.