JP3182734B2 - Marking device using giant magnetostrictive element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marking device for marking a mark by ejecting a liquid.

[0002]

2. Description of the Related Art As a marking device for marking a mark by ejecting a liquid, a pressure / valve opening / closing system and a pressure pulse system are known.

The pressurizing / valve opening / closing system discharges a liquid which is constantly pressurized by opening and closing a valve. That is,
The force for discharging the liquid is a pressure constantly applied to the liquid. A gun is known which has a nozzle connected in close proximity to a chamber filled with pressurized paint, and discharges paint by opening and closing a passage to the nozzle by retreating a spherical valve. (Applicant's 5
No. 8-128658), and an on-demand type printing apparatus in which a plurality of these are arranged in a line has been put to practical use.

On the other hand, in the pressure pulse method, a vibration plate, a vibration bar, or the like is vibrated by a piezoelectric element or the like to generate a pressure wave to form a droplet. In this method, there is no valve structure, so that the structure is not closed, so that the relative position (with respect to the direction of gravity) between the nozzle and the liquid surface cannot be freely selected. Further, since the force due to the pressure wave is relatively weak, the liquid can fly only for a relatively short distance (1-2 mm). Therefore, it is suitable for use in a printer. Also, since the amount of liquid that can be ejected is small, small dots (0.1 to 0.5 m
m) can only be used for marks.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a pressurizing / valve opening / closing type marking device having a new structure, which can respond at high speed, has no restriction on the position and direction of the nozzle, and is located at a relatively large distance. It is an object of the present invention to provide a marking device capable of marking a certain mark surface and marking a relatively large dot.

[0006]

According to the present invention, there is provided a marking device for ejecting a liquid to mark a mark, wherein a wall (2) defining a chamber (1) filled with a paint under pressure is provided. A nozzle (3) connected to the chamber (1) through the passage (4) in close proximity to the chamber (1), a valve seat (5) for opening and closing the passage (4), and facing the valve seat. A valve (6), a giant magnetostrictive element (9) having one end (9 ') relatively fixed to the valve seat (5) and the other end (9 ") facing the direction of the valve seat (5); It has a solenoid coil (10) disposed so as to surround the giant magnetostrictive element (9) in the axial direction, and a movable yoke (7) for connecting the other end (9 ″) of the giant magnetostrictive element to the valve seat (5). And the solenoid coil (10)
When the magnetic field is generated by energizing the element, the displacement of the other end (9 ″) of the giant magnetostrictive element (9) caused by the axial contraction of the giant magnetostrictive element (9) is caused by the movement in the direction of opening the valve (6). This is a marking device where the movable yoke transmits to the valve (6).

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet apparatus using a giant magnetostrictive element is known. However, all of them operate only in the same manner as a conventional electrostrictive element. For example, JP-A-49-
In Japanese Patent No. 84330, ink is ejected by vibrating a pair of magnetostrictive elements in directions opposite to each other to change the internal volume of an ink reservoir. JP-A-55-5997
In the prior art described in Japanese Patent Publication No. 3 (1993), an orifice (nozzle) is made of a magnetostrictive material, and when a magnetic field is applied, the orifice diameter changes and ink droplets are generated. In the invention claimed in this publication, the fluid conduit communicating with the nozzle is formed of a two-layer laminated tube made of a magnetostrictive material, so that not only the generation of ink droplets but also the pumping of ink supply is performed. These configurations are completely different from the present invention.

In FIG. 1, a chamber (1) filled with a pressurized paint (ink or other liquid collectively referred to as paint in the present invention) constantly supplied through a pipe (11). ) Is constituted by the wall (2). In the vicinity of the chamber (1), a passage (4)
A nozzle (3) of 0 to 200 μm is connected to the chamber (1). The passage (4) is opened and closed by a valve seat (5) and a valve (6) facing the valve seat. The valve (6) is connected to the movable yoke (7). The movable yoke (7) is constantly biased in the direction of the valve (6) by adjusting the position of the fixed yoke (20) via the spring (8), so that the valve (6) pushes the valve seat and closes. The valve (6) and the movable yoke (7) may be made integrally.

On the other hand, one end (9 ') of the giant magnetostrictive element (9) is fixed to a fixed yoke (20), and the fixed yoke is fixed to the element holder (21) by screws, while the element holder (21) is It is fixed to the wall (2). Therefore,
One end (9 ') of the giant magnetostrictive element (9) is relatively fixed to the valve seat (5).

[0010] The giant magnetostrictive element itself is known, and there are a positive giant magnetostrictive element whose dimension increases with respect to the driving magnetic field and a negative giant magnetostrictive element whose dimension decreases (for example, industrial materials, 199).
October 2006, vol. 44, no. 11). In the present invention, a negative giant magnetostrictive element is used. The shape of the element can be a cylinder, a prism, a cylinder, or the like, and a cylinder is preferable.

A solenoid coil (10) is disposed so as to surround the axial direction of the giant magnetostrictive element. When the solenoid coil is energized, the axial dimension of the giant magnetostrictive element shrinks, and when the energization is stopped, the dimension returns to the original size. Therefore, the valve (6) can be opened and closed by turning on and off the energization of the solenoid coil.

When the solenoid coil (10) is not energized, the valve (6) contacts the valve seat (5) to close the passage. It is preferable that the fixed yoke can be positioned by being advanced and retracted by screws. Solenoid coil (10)
, The negative giant magnetostrictive element (9) contracts in the axial direction, and the valve (6) moves away from the valve seat (5). This displacement is, for example, on the order of 10 μm, preferably 10 to 40 μm. At this moment, the pressurized paint flows in the direction of the passage, and at the next moment the solenoid coil (10) is de-energized and the valve (6) is closed. Eventually, the droplet becomes the nozzle (3)
Jump out of the tip of the. In this embodiment, the transmission mechanism for transmitting the displacement of the other end (9 ") of the element (9) to the valve (6) as a movement in a direction to open the valve (6) includes the other end (9") of the element (9) ) Is directly connected to the movable yoke (7).
The giant magnetostrictive element can be turned on and off at a high speed of, for example, 5 kHz, and can perform on-demand marking at a high speed.

In the continuous marking, if the current is frequently turned on and off to print dots, the coil generates heat, and if the element itself is vibrated, it generates heat. Due to this heat generation, the temperature of the element holder and the transmission mechanism (especially the movable yoke) also rises and expands, so that the initially set distance between the valve seat and the valve changes, and the paint leaks when the valve is closed. The present inventor has found that there is a tendency to cause a problem that the amount of paint to be discharged when the valve is opened is insufficient. This problem has been solved by selecting the materials of the holder and the transmission mechanism such that the expansion of the element and the transmission mechanism due to the thermal expansion in the axial direction is substantially the same as the expansion of the holder due to the thermal expansion. A simple way to do this is to choose the same coefficient of thermal expansion for the holder and the transmission mechanism as for the element. However, this is not always easy.

Instead of making the thermal expansion coefficients of the three members substantially the same, the length of the portion of the transmission mechanism that is subject to temperature change in the total length of the transmission mechanism ×
The materials (and dimensions) are determined so that the thermal expansion coefficient + element length × element thermal expansion coefficient is substantially equal to holder length × holder thermal expansion coefficient. Here, the portion that receives a temperature change in the entire length of the transmission mechanism is a portion of the movable yoke in the holder in FIG. In this way, the problem caused by heat generation is solved.

The distance between the valve seat and the valve before the operation of the apparatus can be adjusted by moving the fixed yoke forward and backward with screws.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the device of the present invention.

[Explanation of symbols]

 1: chamber 2: wall 3: nozzle 4: passage 5: valve seat 6: valve 7: movable yoke 8: spring 9: giant magnetostrictive element 10: solenoid coil 11: tube 20: fixed yoke 21: element holder

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryusuke Yamaguchi 2-6-1 Funakura-cho, Yokosuka City, Kanagawa Prefecture Within Marktech Co., Ltd. (56) References JP-A-5-312118 (JP, A) JP-A Sho49 -84330 (JP, A) JP-A-5-312118 (JP, A) Japanese Utility Model Application Sho 58-128658 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05B 15/04 B05B 1/30 B41J 3/04

Claims (3)

(57) [Claims] 1. A marking device for ejecting liquid to mark a mark, comprising: a wall (2) forming a chamber (1) filled with a paint under pressure; Nozzle (3), which is connected to chamber (1) via passage (4), said passage (4)
(5), a valve (6) opposed to the valve seat, one end (9 ') is relatively fixed to the valve seat (5), and the other end (9 ") is a valve seat (5). And the solenoid coil (10) disposed so as to surround the axial direction of the giant magnetostrictive element (9), and the other end (9 ″) of the giant magnetostrictive element. A giant magnetostrictive element having a movable yoke (7) for connecting the valve seat (5), wherein the giant magnetostrictive element (9) contracts in the axial direction when a current is applied to the solenoid coil (10) to generate a magnetic field; A marking device in which the movable yoke transmits the displacement of the other end (9 ″) of (9) to the valve (6) as a movement in a direction to open the valve (6). 2. One end (9 ') of the element (9) is connected to the element (9).
Is relatively fixed to the valve seat (5) via the holder (21), and the expansion of the element (9) and the transmission mechanism in the nozzle direction due to thermal expansion is substantially the same as the expansion of the holder (21) due to thermal expansion. The marking device according to claim 1, wherein the materials of the holder (21) and the transmission mechanism are selected so as to satisfy the following. 3. An element (9) is accommodated in an element holder (21), and a space in the element holder (21) communicates with the chamber (1), and the element (9) and the transmission mechanism are being painted. 2. The marking device according to claim 1, wherein there is no sealing member separating the vibrating part comprising the element (9) and the transmission mechanism from the chamber (1).