JPS60222262A - Printing wire driver for printhead - Google Patents

Abstract

PURPOSE:To reduce driving energy along with a larger stroke of a print wire by arranging a surface wave generation mechanism for generating a surface wave to activate the print wire and a pressure contact mechanism for pressing the print wire on the surface wave generation mechanism. CONSTITUTION:When the surface of a metal elastic body 5a with a high coefficient of friction is given a vibration with a piezo-electric element 5b, an elastic wave generates and propagates in the direction of the arrow (a) as illustrated over the surface of the metal elastic body 5a. A pressure contact mechanism 6 is mounted to a frame 2 at the position of grasping the print wire 1 with the surface wave generation mechanism 5 and contains a laminate type piezo-electric element 6a. As the piezo-electric element 6a is energized according to the printing timing, the print wire 1 is pressed on the surface wave generation mechanism 5 through a hold piece 6b with a high coefficient and a high wear resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print wire drive device for a print head used in a print head of a matrix printer.

(Prior art) In print heads that print characters, symbols, etc. using multiple print wires, the use of kanji characters has progressed rapidly in recent years, and market demands require high speed and high print wire mounting density. In addition, as the versatility of devices using these print heads becomes wider, the recording media also become more diverse, and there is a need for devices that can print a large number of prints and have high reliability.

Conventional print heads often have an electromagnet as a basic configuration as a print wire drive means, but when electromagnets are used, magnetic interference occurs between the individual drive means, and the characteristics vary depending on the number of wires driven. There were problems such as , and there was a limit to the stroke of the shiblint wire due to the attraction characteristics of the electromagnet. Furthermore, due to the heat generated by the coil,
The drawback is that there are restrictions on usage.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned drawbacks by driving a print wire using surface waves of an elastic body, to increase the stroke of the print wire, and to reduce power consumption due to low drive energy. The purpose of the present invention is to provide a drive device with a new design.

Another object is to provide a highly reliable drive device that eliminates the magnetic circuit system, has stable characteristics, and is free from magnetic interference between drive means.

[Structure of the invention]

A print wire drive device for a print head according to the present invention includes a surface wave generation mechanism that generates a surface wave that moves the print wire when it comes into contact with the print wire, and a side opposite to the surface wave generation mechanism that sandwiches the print wire. The surface wave generating mechanism generates traveling waves of surface waves on the surface of the elastic body, and generates traveling waves of surface waves on the surface of the elastic body. The act of pressing the print wire against the elastic body drives the print wire.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. First, FIG. 1 is a cross-sectional view of this driving device, in which a print wire 1 is guided by a guide plate 3 held on a frame 2, and its tip is led to a main guide 4.

A surface wave generation mechanism 5 serving as a driving source for the printed wire 1
is arranged so as to be in contact with the lower side of the printed wire 1. Further, a pressing mechanism 6 for controlling the operation of the print wire 1 is fixed to the frame 2 so as to press the print wire 1 against the surface wave generating mechanism 5 from above.

A return spring 7 is fitted into the print wire 1 and is fixed to the rear hole 8 of the frame 2 into which the print wire 1 is inserted and to the protrusion 2a of the frame to which the pressure contact mechanism 6 is attached, and is fixed to the stopper 9. It is located at the end.

Figure 2 shows the relationship between the surface wave generating mechanism 5 and the printed wire 1, and shows a high coefficient of friction! When vibration is applied to the piezo element 5b on the surface of the metal elastic body 5a, an elastic wave is generated and propagates on the surface of the metal elastic body 58 in the direction of arrow a in the figure.

This elastic wave is a surface wave accompanied by a longitudinal wave and a transverse wave, and performs an elliptical motion with a transverse amplitude W and a longitudinal amplitude U as shown in FIG. The elliptical motion of B turns counterclockwise, and can be expressed by the apex velocity vI = 2πfu (f is the driving frequency) at the apex A for each wavelength of the surface wave. 'The print wire 1 is pressed against this surface at the vertices A, . . . , so that the print wire 1 moves in the direction indicated by the arrow by the frictional force with the metal elastic body 8a.

As shown in FIG. 4, the pressure contact mechanism 6 that controls the operation of the print wire 1 is attached to the frame 2 at a position where the print wire 1 is sandwiched between it and the surface wave generation mechanism 5. An element 6a is built-in. By energizing the piezo element 6a in accordance with the printing timing, the print wire 1 is pressed against the surface wave generating mechanism 5 via the hold piece 6b which has a small coefficient of friction and high wear resistance. A certain amount of clearance is always maintained between the print wire 1 and the hold piece 6b. Next, to explain the operation, when printing necessary characters, symbols, etc., the control unit (not shown) sends a signal. is the surface wave generation mechanism 5
is applied to the pressure contact mechanism 6, and the shiblint wire 1 moves in a predetermined direction due to the above-mentioned surface wave. printed wire 1
After the necessary energy is applied, the signal is cut off and the print wire 1 flies freely and performs a predetermined printing operation. After printing, the return spring 7 returns the printer to the position of the system controller 28, thereby completing the series of printing operations.

FIG. 5 shows another embodiment. In this embodiment, a flexible leaf spring 10 is attached to the rear end of the printed wire 1 in place of the return spring 7 in the previous embodiment, and is fixed to the frame 2 to exert a restoring force. This is what I did.

Note that the other configurations and operations are the same as those in the previous embodiment, and redundant explanations will be omitted.

(Effects of the Invention) Since the print wire drive device for a print head according to the present invention is as described above, it is possible to increase the stroke of the print wire and is extremely versatile.

Furthermore, by being able to utilize piezo elements, the driving energy can be reduced, and a device with low power consumption can be provided.

Furthermore, since there is no magnetic circuit system, there is the advantage that there is no magnetic interference between the respective drive means, and a highly reliable device with stable characteristics can be provided.

[Brief explanation of the drawing]

Fig. flE1 is a sectional view of the first embodiment of the present invention, Fig. 2 is an enlarged perspective view of the main part, Fig. 3 is an enlarged view of the main part of the surface generation mechanism,
FIG. 4 is an enlarged perspective view of the pressure contact mechanism, and FIG. 5 is a sectional view of a second embodiment of the present invention. 1°°・Printed wire 2...Frame 5...Surface wave generation mechanism 6...Pressure mechanism 6a...Piezo element 6b
...Hold piece 7...Return spring 10
...Plate spring Figure 1 Figure 3 O Figure 4 Figure 5

Claims (3)

[Claims] (1) A surface-generating mechanism that generates a surface wave that gives motion to the printed wire when it comes into contact with the printed wire, and a surface-generating mechanism that is provided on the opposite side of the printed wire to sandwich the printed wire and convert the printed wire into a surface-wave generating mechanism. A print wire drive device for a print head having a pressure contact mechanism for pressure contact. (2) The print wire drive device for a print head according to claim 1, wherein the pressure contact mechanism includes a stacked piezo element. (3) A print wire drive device in which a halt piece made of a material with a low coefficient of friction and high wear resistance is installed between the piezo element of the pressure contact mechanism and the print wire. A print wire drive device for a print head according to any one of items 1 to 3.