JP3248157B2 - Method of manufacturing piezoelectric wire dot print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a piezoelectric wire dot print head used in a printer.

[0002]

2. Description of the Related Art A piezoelectric wire dot print head has a plurality of printing elements arranged in a housing at a predetermined pitch in a circumferential direction. The printing element is composed of a piezoelectric actuator using a laminated piezoelectric element, a movable body having a wire fixed at the tip, and two substantially parallel leaf springs, and transmits the displacement of the piezoelectric actuator to the movable body in an enlarged manner. And an enlargement mechanism. The print head having such a configuration is mounted on a carrier running along a platen, and operates at a predetermined time to perform printing. Details of the printing procedure are as follows.

In printing, a voltage is applied to a piezoelectric element of a piezoelectric actuator of a predetermined printing element for a predetermined time at a predetermined time. Thereby, the piezoelectric element is displaced by a predetermined amount in the stacking direction. This displacement is enlarged by the enlargement mechanism and transmitted to the movable body, and the wire at the tip of the movable body advances toward the platen to perform printing. At the time of completion of the printing, the application of the voltage to the piezoelectric element is stopped, and the displaced and moved members return to the original state.

[0004]

In this case, when the piezoelectric actuator is driven at a high speed, stress is concentrated on the joint between the leaf spring and the movable body of the magnifying mechanism and the leaf spring breaks, so that it returns after the printing operation. A stopper for locking the movable body is provided in the housing to suppress the movement of the movable body. However, since the relative positional relationship between the movable member and the stopper of each printing element is not constant due to a component error, an assembly error, etc., the printing has been uneven.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a piezoelectric wire dot print head which can eliminate printing variations when a movable body locking stopper is provided.

[0006]

In order to achieve the above object, according to the present invention, a piezoelectric actuator using a piezoelectric element, a movable body having a wire fixed at a tip thereof, and a displacement of the piezoelectric actuator are increased by enlarging the displacement of the piezoelectric actuator. A plurality of printing elements comprising an enlargement mechanism transmitting to the movable body are provided in the housing,
In addition, in a method of manufacturing a piezoelectric wire dot print head, wherein a stopper for locking the movable body of each of the print elements in a return state is provided in the housing, a head in which the print elements are incorporated in the housing is completed. The piezoelectric element is short-circuited in a state close to the body, and in this state, a portion of the movable body that is locked to the stopper is polished so as to be on the same surface, and then the stopper is attached. I do.

[0007]

Since the portions of the movable elements of the print elements which are locked to the stoppers are polished so as to be flush with each other in the restored state, the operation of the movable elements of the respective print elements becomes substantially equal, which is a problem in the prior art. The printing variation that has been occurring is eliminated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is an explanatory view of the structure of the print head of this embodiment.
FIG. 4A shows a wire locking type, and FIG. 4B shows a beam locking type. First, the structure of the print head 1A shown in FIG. 4A will be described.
Is a nose portion, 4 is a plurality of printing elements arranged at a predetermined pitch in the circumferential direction in the housing 2, and 5 is a stopper.

The printing element 4 includes a piezoelectric actuator 6
, A movable body 7, and an enlargement mechanism 8 that enlarges the displacement of the piezoelectric actuator 6 during operation and transmits the displacement to the movable body 7. The piezoelectric actuator 6 includes a stacked piezoelectric element 9 and blocks 10 and 11 fixed above and below the piezoelectric element 9.
And a preload applying member 12 having both ends fixed to the blocks 10 and 11 to apply a preload to the piezoelectric element 9. The block 11 is fixed to a frame 13 in the housing 2.

The movable body 7 is formed by connecting a base of a beam 16 having a wire 15 fixed to a tip thereof to an armature 14. The enlargement mechanism 8 includes two substantially parallel leaf springs 17 and 18.
It is composed of The upper end of the leaf spring 17 is armature 1
4, the lower end is a fixing member 1 attached to the frame 13.
9, the upper end of the leaf spring 18 is fixed to the armature 14, and the lower end is fixed to the fixing member 20.

The rear end of the wire 15 of each printing element 4 is positioned by being locked to the stopper 5 in a return state (non-printing state in which the piezoelectric actuator 6 is not operated).

The structure of the print head 1B will be described with reference to FIG. 4B. The print element 21 includes a piezoelectric actuator 6, a movable body 22, and an enlargement mechanism 8. The movable body 22 is formed by connecting a base of a beam 24 having a wire 23 fixed to the tip of the armature 14, and the projection 24 a of the beam 24 is positioned by being locked to the stopper 5 in a restored state.

In any of the print heads described above, the lower end of the stopper 5 is fixed to a bottom plate 25 integrated with the frame 13, and the electrodes of the piezoelectric elements 9 of each print element are connected to an external connector connected to an external power supply. 26, printed board 2
7, connected via a connector terminal 28.

At the time of printing, a voltage is applied to the piezoelectric element 9 of a predetermined printing element via the external connector 26 at a predetermined time. As a result, the piezoelectric element 9 is displaced upward, and pushes up the movable leaf spring 18 via the fixed member 20. This movement is magnified by the magnifying mechanism 8 to move the movable body 7
(Or the movable body 22), and the wire 15 (or the wire 23) is guided by the nose portion 3 and advances to perform printing. The wire 15 (or protrusion 2) that has completed printing and returned
4a) is locked and stopped by the stopper 5.

In order to solve the conventional problem in the print head having such a configuration and operation (variation occurs in printing because the relative positional relationship between the movable body and the stopper of each printing element is not constant), the present invention provides: The connector terminals 28 of all the piezoelectric elements are short-circuited in a state close to the completed head in which each printing element is incorporated in the housing to eliminate charges.

In this state, the rear end (or protrusion) of the wire of the movable body, which is a part to be locked by the stopper of the movable body, is polished so as to be flush with each other, and then the stopper is mounted in the housing. ing. Next, this processing step will be described with reference to FIGS.

FIG. 2 is a view showing a wire tip polishing process of the print head 1A in a state close to a completed head in which each print element 4 is incorporated in a housing. The wires 15 project irregularly from the front end of the nose 3 as shown in FIG. This is due to dimensional errors and assembly errors of each component. Therefore, first, the front end of this wire 15 is
As shown in (B), it is shaved off.

Next, as shown in FIG. 3, a plate 31 is attached to the end surface of the nose portion 3 so as to cover the end of each wire 15 and then the movable body is polished. Next, this polishing step will be described with reference to FIG. The process up to this point is the print head 1B
The same applies to the case of.

In the case of the wire locking type, as shown in FIG. 1A, a polishing machine mounting table 102 on which a polishing machine 101 is mounted is mounted on the lower surface 13a of the frame 13, and a base of the wire 15 of each movable body 7 is formed. Is polished by a polishing machine 101 so that the end faces become the same. In the case of the beam locking type, FIG.
As shown in (B), a polishing machine mounting base 104 on which a polishing machine 103 is mounted is mounted in the same manner.
The end face a is polished by the polishing machine 103 so as to be the same plane. Each of the polishers 101 and 103 is rotated around a rotation axis perpendicular to the polisher mounts 102 and 104.
Is parallel to the lower surface 13a.

At the time of this polishing, the wire of each movable body is connected to the plate 31.
The movable body does not move because the tip is held down by this, and accurate polishing is possible.

When the polishing is completed as described above, the polishing machine and the polishing machine mounting base are removed, and the stopper 5, the bottom plate 25 and the like are attached, and the print heads 1A and 1B shown in FIGS.
Is completed. In these print heads 1A and 1B, the piezoelectric elements are so arranged that the portions (the rear ends of the wires 15 in the print head 1A and the lower surfaces of the projections 24a in the print head 1B) that are locked to the stoppers 5 of the movable bodies are the same. Since the element 9 is polished with the element 9 short-circuited, the gap between each movable body and the stopper 5 becomes uniform, and the operation of each movable body becomes almost equal.

[0023]

As described above, according to the present invention, the portion of each print element, which is locked to the stopper of the movable member, is polished so as to be on the same surface with the piezoelectric element short-circuited. Therefore, the operation of each movable body is substantially equal. Therefore, it is possible to improve the print quality by eliminating the dispersion of the print which has conventionally been a problem.

[Brief description of the drawings]

FIG. 1 is a view showing a polishing process of a movable body according to an embodiment of the present invention.
(A) shows the case of the wire locking type, and FIG. 1 (B) shows the case of the beam locking type.

FIGS. 2A and 2B are diagrams of a wire tip polishing process according to an embodiment of the present invention, wherein FIG. 2A shows a state where the wire tip is not polished, and FIG.

FIG. 3 is a preparation process diagram for polishing a movable body according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating the structure of a print head according to an embodiment of the present invention;
FIG. 4A shows a wire locking type, and FIG. 4B shows a beam locking type.

[Explanation of symbols]

 1A, 1B Print head 2 Housing 4, 21 Print element 5 Stopper 6 Piezoelectric actuator 7, 22 Movable body 8 Magnifying mechanism 9 Piezoelectric element 14 Armature 15, 23 Wire 16, 24 Beam 24a Projection

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeo Miura 1015 Kamiodanaka Nakahara-ku Kawasaki City Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yuji Oshime 1015 Kamiodanaka Nakahara-ku Kawasaki City Kanagawa Prefecture Fujitsu Limited ( 56) References JP-A-3-61047 (JP, A) JP-A-2-39948 (JP, A) JP-A-3-71855 (JP, A) JP-A-2-76747 (JP, A) JP 62-51461 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/295 B41J 2/235

Claims (1)

(57) [Claims] 1. A piezoelectric actuator (6) using a piezoelectric element (9), and a movable body (7) having a wire fixed to a tip.
And a plurality of printing elements (4) comprising an enlargement mechanism (8) for expanding the displacement of the piezoelectric actuator (6) and transmitting the displacement to the movable body (7). A method for manufacturing a piezoelectric wire dot print head, wherein a stopper (5) for locking the movable body (7) of each print element (4) in a reset state is provided in the housing (2). The piezoelectric element (9) is short-circuited in a state close to the completed head in which each printing element (4) is incorporated in the housing (2). In this state, the stopper (5) of the movable body (7) is short-circuited. A method of manufacturing a piezoelectric wire dot print head, comprising: polishing a portion to be locked to the same surface; and then attaching the stopper (5).