JPH0976495A - Laminating type ink jet system recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the electric resistances of respective lead patterns without necessitating the widening of the breadth of a cable. SOLUTION: Nearly at the middles of the lead parts 31 and 31' made of an electrical insulating material in a continuous form, which are twice as long as the length necessary for connecting an actuator unit and an external driving circuit and foldable, projected parts 32 and 32' with a breadth W for connecting two connecting terminals are formed. Further, as the projected parts 32 and 32', connecting parts 35 and 35', which have the array pitches coinciding with those of the connecting terminals connecting with piezoelectric vibrators are formed. Furthermore, at the respective lead parts 31 and 31', electrically conductive patterns 36 and 36', which have electrically conductive relationships with the respective connecting parts 35 and 35' by bisecting the connecting parts 35 and 35' into the lead part sides respectively, are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head in which a nozzle plate, a flow path forming member and a vibration plate are laminated, and a flexural vibration mode piezoelectric vibration plate is attached to the surface of the vibration plate.

[0002]

2. Description of the Related Art In an ink jet recording head in which a nozzle plate, a flow path forming member, and a vibration plate are laminated, and a piezoelectric vibration plate of a flexural vibration mode is attached to the surface of the vibration plate, most of these members are made of ceramic. Because
By stacking each member in the state of a green sheet and fixing it by firing it without using an adhesive, there is an advantage that the joining process is unnecessary and the manufacturing process can be simplified. There is. Since such a recording head receives a drive signal from the outside, the individual electrodes of the piezoelectric vibrating plate are connected to an external drive circuit via a flexible cable.

[0003]

However, in a recording head in which a large number of nozzles are formed in order to improve the printing quality and the printing speed, the number of individual electrodes becomes extremely large. Inevitably, the number of conductive patterns to be formed on the flexible cable that supplies the drive signal increases. In addition, the maximum width of the flexible cable is limited to the width of the actuator unit so that it does not interfere with the connection with other actuator units, so the width needs to be reduced as the number of conductive patterns increases. It is necessary to form as many conductive patterns as possible. Therefore, the resistance value of the conductive pattern increases,
There is a problem in that the voltage of the drive circuit is increased and the drive power is increased. Further, in the laminated ink jet recording head using the flexural vibration of the piezoelectric vibrator, since the electrostatic capacity of the piezoelectric vibrator is large, a driving signal whose level greatly changes in an extremely short time is applied for high speed driving. However, when the electric resistance of the conductive pattern of the flexible cable is large, a large time constant occurs due to the capacitance of the piezoelectric vibrator,
There is a problem that it becomes impossible to supply the drive signal as intended to the piezoelectric vibrator. .

The present invention has been made in view of the above problems, and an object thereof is to form a conductive pattern having a width as wide as possible without increasing the width of the flexible cable. An object of the present invention is to provide an ink jet recording head that can reduce the electric resistance of a signal transmission path.

[0005]

In order to solve such a problem, according to the present invention, at least a first surface is provided with a piezoelectric vibration plate and a connection terminal having a conductive relationship with a drive electrode of the piezoelectric vibrator. An actuator unit in which a lid member and a spacer whose one surface is sealed by the lid member to form a pressure generating chamber are integrally joined by firing, and the actuator unit is fixed to the pressure generating chamber. An ink supply port forming substrate having a communication hole and an ink supply port that communicate with each other, a common ink chamber that communicates with the pressure generation chamber via the ink supply port, and a communication hole that communicates with the pressure generation chamber. A common ink chamber forming substrate provided and a nozzle opening that seals the other surface of the common ink chamber forming substrate and is connected to the pressure generating chamber via each of the communication holes are provided. Laminating a flow path unit formed by joining a nozzle plate, in the stacked type ink jet recording head formed by bonding the actuator unit includes a pressure generating chamber of the two rows to a central substantially subject,
Equipped with two rows of connection terminals corresponding to the pressure generating chambers, and having a length twice as long as the length required to connect the actuator unit and an external drive circuit, the foldable elongated electric A protrusion having a width that straddles the two connection terminals is formed substantially in the center of the lead portion of the insulating material, and the protrusion has a connection portion matching the arrangement pitch of the connection terminals, and each lead. Forming a conductive pattern having a conductive relationship with each connecting part by dividing the connecting part into two parts on the side of each lead part, and folding back in the vicinity of the boundary line of the convex part to conduct the connecting part to the connection terminal. I fixed it by having a relationship.

[0006]

Since the conductive pattern for individually supplying the drive signal to each piezoelectric vibrator of the actuator unit is divided into two directions, the width per conductive pattern can be widened. The electric resistance of the conductive pattern is reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is an assembly perspective view showing an embodiment of a recording head of the present invention, and FIG. 2 is a view showing a sectional structure in the vicinity of one pressure generating chamber, in which reference numeral 2 is a first.
Is a lid member made of a zirconia thin plate having a thickness of about 10 μm, and the individual 4 serving as one pole is formed on the surface of the thin plate.
Piezoelectric vibrating plates 5 and 5'made of PZT or the like are fixed thereon so as to face pressure generating chambers 3 and 3, which will be described later, and common electrodes 6 and 6'are formed on the surfaces thereof.

Reference numerals 7 and 7 are connection terminals formed on the sides of the first lid member 2, and are formed by a conductive pattern for extraction formed by vapor-depositing a conductive material at the same time when the individual electrodes 4 and 4'are formed. A flexible cable 30 to be described later is electrically connected to each of the individual electrodes 4 and 4 ', and the surface thereof is preferably located above the electrodes 6 and 6'on the surface of the piezoelectric vibrators 5 and 5, and the flexible cable 30 described later is a piezoelectric vibrator. The height is set so as not to come into contact with 5, 5 '.

Reference numeral 8 denotes a spacer, which is formed by forming a through hole in a ceramic plate of zirconia (ZrO2) or the like having a thickness suitable for forming the pressure generating chambers 3 and 3 ', for example, 150 μm, which will be described later. Both surfaces are sealed by the second lid member 9 and the first lid member 2 to form the pressure generating chambers 3 and 3'described above.

Reference numeral 9 is a second lid member, which is also described later on the ceramic plate of zirconia or the like, and ink supply ports 13 and 13 '.
And communication holes 10, 10 'for connecting the pressure generating chambers 3 and 3'
And the nozzle communication holes 11 and 11 ′ that connect the nozzle openings 18 and 18 ′ and the other ends of the pressure generating chambers 3 and 3 ′, respectively, and are fixed to the other surface of the spacer 8.

These members 2, 8 and 9 are assembled in the actuator unit 1 without using an adhesive by molding a clay-like ceramic material into a predetermined shape and stacking and firing it. .

Reference numeral 12 denotes an ink supply port forming substrate which also serves as a fixed substrate of the actuator unit 1 and has a common ink chamber 1 which will be described later on one end side of the pressure generating chambers 3 and 3 '.
Ink supply ports 13 and 13 'for connecting the pressure generating chambers 3 and 3'to the pressure generating chambers 3 and 3'are provided, and nozzles for connecting to the nozzle openings 18 and 18' are provided on the other end side of the pressure generating chambers 3 and 3 '. Communication holes 14 and 14 'are provided.

Reference numeral 19 denotes a common ink chamber forming substrate, which is connected to the common ink chambers 15 and 15 'for receiving the inflow of ink from an ink tank (not shown) and the nozzle communication holes 16 and 16 for connecting the nozzle openings 18 and 18'. ′ Is provided, and the other surface is sealed by the nozzle plate 17 to form common ink chambers 15 and 15 ′.

Reference numeral 17 denotes the above-mentioned nozzle plate, which is the nozzle communication holes 11, 14, 16 and the nozzle communication holes 11 ', 1'.
Nozzle openings 18, 18 'are formed so as to communicate with the pressure generating chambers 3, 3'via 4', 16 '.

The ink supply port forming substrate 12, the common ink chamber forming substrate 19, and the nozzle plate 17 are
They are fixed to each other with an adhesive layer such as a heat-welding film or an adhesive, and are assembled in the flow path unit 20.

A recording head is constructed by fixing the flow path unit 20 and the actuator unit 1 with a heat-welding film or an adhesive.

Reference numeral 30 denotes a flexible cable which is a feature of the present invention, and is a distance L for connecting the recording head and the drive circuit.
The lead portions 31, 31 'having a length equal to or greater than the above, and the convex portions 32, 32' having a width W capable of straddling the connection terminals 7, 7'of the actuator unit 1 are provided in the central portion. The conductive film is used as a base material 33, and on the surface thereof, connecting portions 35, 35 'and conductive patterns 36, 36' for forming a conductive relationship with the connecting portions and connecting to an external driving circuit are formed.

When the base material is fixed to the connection terminals 7 and 7'by soldering, it is desirable to use a material having heat resistance such as polyimide.

FIGS. 4 and 5 show an embodiment of the above-mentioned flexible cable 30, respectively.
32 'is a connection terminal 7 of the actuator unit 1,
The connection portions 35, 35 'suitable for solder connection are formed in conformity with the arrangement pitch of 7'.

These connecting portions 35, 35 'are divided into two in the longitudinal direction of the cable. One half (the lower one in the drawing) is the conductive pattern 36 of the lead portion 31, and the other half (the upper one in the drawing). Is the conductive pattern 3 of the lead portion 31 '.
It is connected to 6 '.

Further, common electrode connecting patterns 38, 38 'for connecting the electrodes 6, 6'to an external drive circuit are formed at positions overlapping the common electrodes 6, 6'.

An insulating protective film 37 is formed on the surfaces of the conductive patterns 36 and 36 ', and the end portion of one lead portion 31 exposes a part of the conductive pattern 36 without forming the insulating protective layer 37. Exposed portion 36a, and the other end portion of the lead portion 31 'is stripped of the base material 33 to form an exposed portion 36a' exposing a part of the conductive pattern 36 '. These exposed portions 36a, 36a' are formed. Is a connection portion with an external circuit.

In the vicinity of the folded portion of the flexible cable 30, a part 30a of the base material 30 is peeled off so that the rigidity of the folded portion is weakened and the bending is facilitated. By folding the flexible cable 30 in this way, it can be routed in the same manner as a single cable, and not only is it easy to handle, but it can also be matched to the thinness of the laminated inkjet recording head for recording. The entire head can be easily handled.

The flexible cable 30 having the above-described structure has the surface of the common electrodes 6, 6'in the state where the solder paste is applied to the terminal portions 35, 35 'or the connection terminals 7, 7'of the actuator unit 1 in advance. When the positioning marks 24, 24 formed on the wiring and the marks 39, 39 'formed on the common electrode connecting patterns 38, 38' of the flexible cable 30 are aligned so as to be aligned, The connecting portions 35, 35 ′ of the cable 30 have terminals 7 of the actuator unit 1,
Match 7 '.

In this state, the solder paste is heated from the surface of the base material 33 of the flexible cable 30 to a temperature sufficient to melt the solder paste, and soldering is performed, and the solder connection between the flexible cable 30 and the actuator unit 1 is completed. Then, in the vicinity of the boundary with the convex portions 32, 32 ', one lead portion 31' is bent so as to overlap the other lead portion 31, and the conductive patterns 36, 36 'at each end are exposed at their exposed portions 36a, 36a'. Connection terminal B of the board A of the drive circuit,
Solder to C.

When the flexible cable 30 is bent, the flexible cable 30 is turned upside down, one exposed portion 36a is formed by peeling off the insulating protective layer 37, and the other exposed portion 36 'is formed by peeling off the base material 33. Therefore, the connection can be made on the same surface of the substrate A, and the connection work can be simplified.

According to this embodiment, conductive patterns 36 and 36 'for individually supplying drive signals to the respective piezoelectric vibrators 4 and 4'of the actuator unit 1 are formed by being divided in two directions. Therefore, the conductive patterns 36, 36'1
The width per book can be wide, and the conductive pattern 3
Signal loss can be reduced by reducing the electrical resistance of 6, 36 '.

That is, in the present invention, the conductive patterns 36, 36 ', 38, 3 of the flexible cable 30 are used.
Since the resistance of 8'is small, even if a drive signal whose voltage changes by about 35 V within a time of about 2 μsec is applied to the piezoelectric vibrators 5 and 5'having large electrostatic capacitance, the piezoelectric vibration is not delayed. The sub-elements 5 and 5'receive a drive signal within 2 .mu.sec and generate a displacement necessary for ink droplet ejection.

Further, in the present invention, since the width can be set to be approximately twice the width W which is restricted by the size of the recording head, it is not necessary to form a pattern of the conductive patterns with an excessively small array pitch, and a small array is provided. It is possible to reliably prevent a short circuit between conductive patterns due to the pitch and signal interference.

[0030]

As described above, in the present invention,
A width that straddles two connection terminals is provided almost at the center of the lead portion of the long foldable electrically insulating material having a length twice the length required to connect the actuator unit and the external drive circuit. In addition to forming the convex portion provided, the convex portion is provided with a connecting portion matching the arrangement pitch of the connecting terminals, and each lead portion is divided into two connecting portions on the side of each lead portion to provide a conductive relationship with each connecting portion. Since the conductive pattern is formed and folded back near the boundary of the convex part to fix the connecting part so that the connecting terminal has a conductive relationship, it does not lead to widening of the lead part of the flexible cable. The width of the pattern can be made about twice as wide as the conventional one, and the drive signal can be supplied to the piezoelectric vibrators arranged at high density without causing power loss or voltage drop.

[Brief description of drawings]

FIG. 1 is an assembled perspective view showing an embodiment of an ink jet recording head of the present invention.

FIG. 2 is a cross-sectional view showing the structure of the ink jet recording head in the vicinity of the pressure generating chamber.

FIG. 3 is a diagram showing a structure of a connection terminal formed on a surface of an actuator unit.

FIG. 4 is a diagram showing an example of a conductive pattern formed on a flexible cable connected to the ink jet recording head.

FIG. 5 is a view showing a cross-sectional structure of the above flexible cable.

[Explanation of symbols]

 1 Actuator Unit 2 First Lid Member 3, 3'Pressure Generation Chamber 4, 4'Individual Electrode 5, 5'Piezoelectric Vibrating Plate 6, 6'Common Electrode 7,7 'Connection Terminal 18, 18' Nozzle Opening 20 Flow Path Unit 30 Flexible cable 31, 31 'Lead part 32, 32' Convex part 33 Base material 35, 55 'Connection part 36, 36', 38, 38 'Conductive pattern

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazumi Kamoi 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation

Claims (7)

[Claims] 1. A first lid member having at least a piezoelectric vibrating plate on the surface thereof and a connection terminal having a conductive relationship with a drive electrode of the piezoelectric vibrator, and one of the surfaces is sealed by the lid member and pressure is applied. An actuator unit formed by integrally bonding a spacer forming a generation chamber by firing, and an ink supply port forming substrate having an ink supply port and a communication hole to which the actuator unit is fixed and which communicates with the pressure generation chamber. A common ink chamber forming substrate having a common ink chamber communicating with the pressure generating chamber via the ink supply port, and a communication hole communicating with the pressure generating chamber;
Laminating and adhering a flow path unit formed by joining the other surface of the common ink chamber forming substrate and a nozzle plate having a nozzle opening connected to the pressure generating chamber via each of the communication holes. In the laminated ink jet recording head as described above, the actuator unit includes two rows of pressure generating chambers so as to substantially target the center, and two rows of connection terminals corresponding to the pressure generating chambers. The two connecting terminals are straddled in a substantially central portion of a lead portion of a long foldable electrically insulating material having a length that is twice the length required to connect the actuator unit and an external drive circuit. While forming a convex portion having a width, the convex portion has a connecting portion that matches the arrangement pitch of the connection terminals, and the lead portion is divided into two connecting portions on the lead portion side. Forming a conductive pattern having a conductive relationship with each connection part, and folding back near the boundary line of the convex part, and fixing the connection part so that the connection terminal has a conductive relationship and is fixed. Recording head. 2. The laminated ink jet recording head according to claim 1, wherein the conductive pattern at one end of the lead portion is exposed. 3. The laminated ink jet recording head according to claim 1, wherein the electrical insulating material is made of a heat resistant material, and the fixing is soldering. 4. The laminated ink jet recording head according to claim 1, wherein the conductive pattern is covered with an electrically insulating layer. 5. A positioning mark is provided on each of the first lid member and the flexible cable so as to match when a connection terminal of the first lid member and a connection portion of the flexible cable match each other. Claim 1
Stacked type ink jet recording head. 6. The laminated ink jet recording head according to claim 1, wherein the electrical insulating material is peeled off in the vicinity of the bent region. 7. The electrical insulating material so that each end of the folded lead portion exposes the conductive pattern on the same surface.
Alternatively, the laminated ink jet recording head according to claim 4, wherein the electrically insulating layer is peeled off.