JPH01184153A - Printing head - Google Patents

Abstract

PURPOSE:To achieve high speed printing and to enhance durability, by connecting the fulcrum to be driven of a magnifying mechanism, which energizes the reciprocating movement of a printing wire, and a drive means through the first leaf spring and setting a revolving fulcrum in close vicinity to the fulcrum to be driven and connecting the revolving fulcrum and a base member through the second leaf spring. CONSTITUTION:The actuator assembly 7 constituting the actuator bank 2 of a printing head 1 has a base 8 and the piezoelectric element 9 as the drive means of the magnifying mechanism 20 supported by said base 8. An inner block 10 is fixed to the leading end of the piezoelectric element 9 and one end (base end) of the first spring (center spring) 11 is fixed to the other end part of said element 9 and the other and (leading end) of this spring 11 is fixed to a top block 12. The base 8 is connected to the top block 12 through the leading end thereof and a pair of the second leaf springs (side springs) 13 provided to the left and right of the spring 11. A pair of the side springs 13 are provided at a close position forward from the spring 11 by a distance A in a printing direction. The base end of a plate-shape arm 14 is fixed to the top block 12 and the base end of a wire 15 is fixed to the leading end thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print head device, and more particularly to a print head device for a dot impact printer using a large number of wires.

[Conventional technology]

In general, a print head device for a dot impact printer using a large number of wires has a structure in which a plurality of actuators each having a proximal end of the wire fixed therein are arranged radially in a number equal to the number of wires.

Actuator drive methods are roughly divided into two types: those using electromagnets and those using piezo elements (piezoelectric elements).

Among these, two methods use electromagnets, which attract the actuator with the attraction force generated by energizing the electromagnet and move the wire to obtain printing force. The actuator is attracted in the opposite direction to the printing direction by the attractive force of the permanent magnet against the tensile force of the spring, and when printing, electricity is supplied to the electromagnet that generates a magnetic field that counteracts the attractive force of the permanent magnet. There is a method in which printing is performed by moving an actuator forward using the energy of a spring.

In addition, the method that uses piezo elements transmits the deformation of the piezo element that deforms when energized to the actuator via a motion magnification mechanism, which drives the printing wire and prints, meeting the demand for faster printers. A relatively large number of them have been developed in recent years.

[Problem to be solved by the invention]

However, in the case of the conventional method using electromagnets described above, heat is generated when the coil is energized to generate a magnetic field, which limits the usage duty and also reduces the energy that can be generated by the electromagnet. However, if the printer is small, the printing speed will be slow, and if the printing speed is increased, the electromagnet and actuator will become larger, resulting in an increase in the size of the entire print head device.

On the other hand, most of the methods that use piezo elements directly utilize the deformation of the piezo elements, so a mechanism for enlarging the operation is necessary in order to obtain sufficient printing force. This had the disadvantage of increasing its size. In addition, devices have been devised that indirectly utilize the deformation of the piezo element by using a motion amplification mechanism with a complicated structure, but this method has the problem of high cost.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and, in particular, to provide a relatively inexpensive print head device that can realize high-speed printing.

[Means to solve the problem]

The present invention includes an enlarging mechanism that urges the reciprocating movement of a printing wire at one end and has a rotating fulcrum and a driven fulcrum at the other end, a driving means for driving the enlarging mechanism, and a driving means for driving the enlarging mechanism. and a supporting base member. and,
The driven fulcrum of the enlarging mechanism and the driving means are integrally connected via the first leaf spring, and the rotating fulcrum of the enlarging mechanism is set close to the driven fulcrum, and the rotating fulcrum of the enlarging mechanism is A configuration is adopted in which the fulcrum and the base member are integrally connected via a second leaf spring. This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

As shown in FIG. 3, the print head device 1 of this embodiment includes an actuator bank 2, a head frame 3 fixed to the printing surface side of the actuator bank 2 (left side in FIG. 3), and a printing surface side of the actuator bank 2. is equipped with a rear cover 4 fixed on the opposite side.

Among these, the actuator bank 2 is composed of a disk-shaped mount base 5 having a circular opening 5a in the center, and an actuator assembly 7 fixed to the front and back surfaces of the mount base 5 with screws 6. . In this embodiment, the mount base 5 uses a ferrite vibration damping member.

As shown in FIG. 2, the actuator assembly 7 includes a base 8 as a base member which is formed into a substantially U-shape and is fixed to the mount base 5 side during assembly, and an enlargement mechanism supported by the base 8, which will be described later. It has a rectangular stacked piezo element 9 as a driving means for driving the piezo element 20. Specifically, the piezo element 9 is fitted into the linear notch 8a of the base 8, and its end (base end) is inserted into the base 8.
It is fixed to the inner part of the notch part 8a on the base side of the cutout part 8a.

An inner block 10 is attached to the other end (tip) of the piezo element 9.
is fixed. One end (base end) of a center spring 11 as a first leaf spring is fixed to the end of the inner block 10 opposite to the piezo element 9, and the other end (tip) of this center spring 11 is fixed to the top block 12. It is fixed;
Thereby, the center spring 11 integrally connects the top block 12 and the inner block 10.

Further, one ends (base ends) of side springs 13, 13 as second leaf springs are fixed to the tips of the left and right arms of the base 8 in FIG. 2, respectively, on the left and right sides of the center spring 11.
The other end (tip) of each side spring 13 is a top block 12
The side spring 13 integrally connects the top block 12 and the base 8.

Both side springs 13, 13 are arranged on substantially the same plane. In addition, the center spring 11 and the side springs 13, 13
are not in the same plane, and the side spring 13 is located closer to the front by a distance A in the printing direction indicated by the arrow in FIG.

As shown in FIG. 1, one end (base end) of a flat plate-shaped arm 14 is fixed to the top block 12 while being positioned within a plane facing the printing direction, and the other end (tip) of the arm 14 is fixed to the top block 12. The base end of the wire 15 is fixed in the printing direction.

Note that the distance from the lower surface of the top block 12 to the tip of the arm 14 is set to B (see FIG. 1). In this embodiment, the above-mentioned top block 12 and arm 14 constitute an enlarging mechanism 20 that urges the reciprocating movement of the printing wire at one end and has a rotating fulcrum and a driven fulcrum at the other end. ing. Therefore, when the piezo element 9 is energized, the piezo element 9 expands and the enlarging mechanism 20
is driven upward in FIG. 1 via the driven fulcrum, that is, the fixed end of the center spring 11 on the side of the top block 12, and the top block 12 is integrally connected to the base 8 by side springs 13. Therefore, the enlarging mechanism 20 eventually expands the side springs 13, 13 on the top block 12 side.
The wire is rotated in the printing direction around the fixed end (rotation fulcrum), the wire moves forward, and printing is performed.

Actuator assembly 7 configured as above
are fixed to the front and back surfaces of the mount base 5 in a staggered and radial manner.

Further, the head frame 3 is fixed to the printing direction side of the mount base 5 with screws 16.

The head frame 3 has a cylindrical portion 3a protruding from the center thereof in the printing direction.

In this cylindrical part 3a, intermediate guides 17, 18 are provided which guide the wires 15 into a predetermined arrangement. A main guide 19 is fixed to the tip of this cylindrical portion 3a to ensure printing accuracy.

On the other hand, on the opposite side of the mount base 5 from the printing direction, a disc-shaped roller cover 4 is fixed with screws 20. Further, a stopper 21 of the arm 14 located on the printing direction side of the mount base 5 is provided near the center of the mount base 5, and a stopper 21 of the arm 14 located on the rear side of the printing direction is fixed to the rear cover 4 side. There is.

Next, a method of assembling and operation of the print head device according to this embodiment configured as described above will be explained.

Since the actuator assembly 7 is fixed in advance to the front and back surfaces of the mount base 5 made of a damping material, it can be handled as one component, that is, the actuator bank 2.

By fixing the head frame 3 and rear cover 4 to the mount base 5 of the actuator bank 2, the print head device 1 can be assembled extremely easily.

Predetermined piezo elements 9 of the assembled printhead device 1
When energized, the piezo element expands, and as a result, the enlarging mechanism 20 rotates counterclockwise in FIG. I do.

The amount of movement of the wire 15 at this time is based on the "lever" principle.
The amount of elongation of the piezo element 9 is X (B/A).

On the other hand, when the piezo element 9 becomes de-energized, it returns to its original state, so the movement magnifying mechanism 20 rotates in the opposite direction (clockwise in FIG. 1), and the wire 15 returns to its original state. Return to position.

In this way, printing is performed by enlarging the slight expansion and contraction of the piezo element 9 via the enlarging mechanism 20 and driving the wire 15 back and forth.

In reality, the amount of elongation of the piezo element is about 1/100 mm, and the coefficient of thermal expansion of the element is close to zero. Therefore, in this embodiment, the material of the base 8 is selected to have the same coefficient of thermal expansion in order to eliminate the influence of heat as much as possible.

As explained above, in this embodiment, the piezo element 9
It is possible to drive the wire 15 by magnifying the slight expansion and contraction of B/A. Further, since the distance A is small, that is, the driven fulcrum and the rotational fulcrum of the enlarging mechanism 20 are set close to each other, the enlarging mechanism 20 can be sufficiently miniaturized.

Further, since the center spring 11 and the side springs 13 are used, the piezo element 9 can be structurally sufficiently durable even if the piezo element 9 is expanded and contracted quite frequently and at high speed.

Furthermore, in this embodiment, since the mount base 5 is made of a vibration damping member as described above, the vibration of the actuator assembly is suppressed during the printing operation, and
There is an advantage that extra high-order vibration modes are not transferred to the actuator assembly side, and therefore high-speed printing is possible.

〔Effect of the invention〕

Since the present invention is configured and functions as described above, according to this, when the reciprocating rotation of the enlarging mechanism accompanied by the reciprocating movement of the printing wire is repeated many times and performed at high speed, the first . Second
This can be sufficiently handled by the action of the leaf spring.

Furthermore, since the driven fulcrum and rotational fulcrum of the enlarging mechanism are set close to each other, for example, by using a simple enlarging mechanism as in the above embodiment, the enlarging ratio is sufficient and the overall A compact enlarging mechanism can be realized.

Therefore, it is possible to realize high-speed printing using a piezo element or the like with quick response as a driving means, and to provide a relatively inexpensive print head device with unprecedented durability.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an actuator assembly which is the main part of an embodiment of the present invention, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a print head device equipped with the actuator assembly of FIG. 1. A partially broken overall explanatory diagram showing the
FIG. 4 is a partially cutaway right side view of FIG. 3. 7... Actuator assembly, 8. Old.
・Base, 9...Piezo element, 10...
・Inner block, 11...Center spring, 1
2... Top block, 13... Side spring, 14... Arm, 15... Wire, 20... Enlargement mechanism. Fig. 1 Alignment 1-Lead Fig. 2 Fig. 3 Fig. 7

Claims (1)

[Claims] (1) An enlarging mechanism that urges the reciprocating movement of the printing wire at one end and has a rotating fulcrum and a driven fulcrum at the other end, a driving means for driving the enlarging mechanism, and a driving means for driving the enlarging mechanism. In the print head device, the driven fulcrum of the enlargement mechanism and the driving means are integrally connected via a first leaf spring, and the driven fulcrum of the enlargement mechanism is integrally connected with the driving means, and the A print head device characterized in that a rotation fulcrum of an enlarging mechanism is set, and the rotation fulcrum of the enlarging mechanism and the base member are integrally connected via a second leaf spring.