JPS61228963A - Printer - Google Patents

Abstract

PURPOSE:To prevent the occurrence of blocking due to the vaporization of ink by supplying sufficient amounts of ink to the tip of a recording electrode by using a recording electrode formed of small tubes having many through holes along the longitudinal direction. CONSTITUTION:A recording electrode 17 is formed of fine tubes 23 having many through holes 22 in the longitudinal direction, which are obtained by molding a mixture of alumina (Al2O3) fine powder and a binder by extrusion and then by sintering it. The fine tube 23 having many through holes 22 of about 50mum diameters in the longitudinal direction is a columnar part of about 0.8mm diameters and about 10mm lengths, and its tip 4 is processed into a conical form of a top angle of 60 deg. and 0.15R. A metal (Cr) thin film having an electric conductivity is formed on the surface of the fine tube 23. Ink 1 passes through the holes of the electrode 17, flows along the longitudinal direction, and is supplied in sufficient amounts to the tip 4.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is characterized in that dots are formed on a recording medium by ejecting liquid ink using an electric field, and images such as characters and figures are formed by the combination of these dots. The present invention relates to printing devices.

2. Description of the Related Art Conventionally, an image is formed on a recording medium by ejecting droplets of liquid ink from a nozzle. The so-called inkjet printer
Many inventions have been made and improvements have been made for reasons such as less noise during printing and advantages in terms of running costs when performing multicolor printing compared to other printing methods. However, countermeasures against nozzle clogging due to ink evaporation are not sufficient and have become a practical problem.

In order to eliminate the occurrence of such nozzle clogging, a type of printer using liquid ink that is different from the above-mentioned inkjet printer is being considered.

First, to give an example, as described in JP-A-56-170 and JP-A-56-4467,
A slit-shaped opening is formed in place of a nozzle that is prone to clogging, and an electric field is applied between opposing electrodes facing this opening to cause ink to fly.

This type of ink has a problem in that the structure for releasing ink droplets from the slit-shaped opening is delicate and lacks stability.

In addition, as for other methods, Japanese Patent Application Laid-Open No. 54-2353
As seen in Japanese Patent No. 4 and Japanese Patent Laid-open No. 159355/1983, ink is guided to the tip of a needle-like member along the outer periphery, and the ink is caused to fly by electric field.

In this type of product, magnetic ink must be used to guide the ink to the tip of the needle-like member, and this magnetic ink has a high degree of freedom in color selection due to the ground color of the magnetic powder contained in it. The disadvantage is that there is no

Problems to be Solved by the Invention In order to solve the disadvantages of the above-mentioned inkjet printer using liquid ink while maintaining its features, it is necessary to avoid clogging in the part where the ink is ejected. is absolutely necessary.

Furthermore, the use of magnetic ink as the liquid ink is undesirable due to its color, and it must be possible to print with ordinary water-based ink.

Means for Solving the Problems In order to solve these problems, Mizude Manjin invented a printing device of the type shown in FIG. 7 and filed a patent application.

First, an ink container 2 for storing ordinary liquid ink 1 is provided, and a needle-shaped recording electrode 3 having electrical conductivity and ink-impregnating property is provided inside the ink container 2 and immersed in the ink 1. The tip 4 of the electrode 3 is exposed from the ink container 2. A counter electrode 6 is provided at the tip 4 of the recording electrode 3 with a recording paper 5 interposed therebetween. , 9 are connected. A control circuit 10 is connected to the switching circuit 7 and generates a control signal according to the image signal.

The following recording electrodes 3 are used as the above-mentioned recording electrodes 3.

(1) Metal particles formed by casting without losing air permeability (2) Sintered conductive particles such as transition metal oxides (3) Conductive particles mixed with carbon fine particles Among these breathable foam molded plastic products, (1) and (2) are a collection of irregularly shaped particles, and the pores formed between the particles communicate three-dimensionally. Further, (3) also has a substantially similar structure.

Therefore, the ink 1 always reaches the tip 4 of the recording electrode 3, and the switching circuit 7 operates according to the image signal to generate an electric field between the recording electrode 3 and the counter electrode 6.
The ink 1 is ejected from the tip 4 toward the recording paper 5.

Printing is performed according to this principle, but since the tip 4 of the recording electrode 3 is exposed to the outside, the ink 1 in that part dries, but the fluid flow rate with the ink 1 in the ink container 2 is low. Since this is high, the density of the ink 1 can be uniformized well, and no slag of the ink 1 is generated at the tip 4.

As described above, this type of printing device is a dramatic advance over conventional technology, but in order to increase the printing speed, it is necessary to eliminate the risk of droplets and to use even more ink.
It is necessary to increase the supply of That is, it is desirable that the recording electrode 3 has a high ability to retain the ink 1 and a low fluid resistance.

Means for Solving the Problems A recording electrode of a printing device is formed by a through-hole thin tube in which a large number of through-holes are formed along the longitudinal direction.

The working ink flows in the length direction of the recording electrode, and because of the presence of a large number of through holes, the ink is abundantly supplied to the tip of the recording electrode. Further, clogging due to ink evaporation does not occur.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. Components that are the same as those described in connection with FIG. 7 are designated by the same reference numerals, and description thereof will be omitted. First, two guide shafts 12 (only one is shown in FIG. 1) are provided horizontally on the front side of the printer 11, and a carrier 13 is mounted on these guide shafts 12 so that they can freely reciprocate from side to side. is attached to. A print head 14 is placed on this carrier 13 . Further, in the center of the printer 11, a counter electrode 6 facing the print head 14 is horizontally attached. A tractor 15 for feeding recording paper 5 as a recording medium is provided behind this counter electrode 6. An operating knob 16 projecting outward is coupled to the tractor 15.

The print head 14 is similar to that shown in FIG. 7, but the recording electrode 17 has a different structure as will be described later. The upper surface of the ink container 2 is covered with a printed wiring board 18, and the wire 1 is electrically connected and fixed to the printed wiring board 18.
The recording electrode 17 is held at the tip of the electrode 9 . Also,
The printed wiring board 18 is connected to a connector 20,
This connector 20 is connected to a switching circuit 21.

Therefore, the recording electrode 17 is made of alumina (Al, Oa
) is kneaded with a binder, extruded by a special method, and then sintered to form a through-hole thin tube 23 having a large number of through-holes 22 in its longitudinal direction. That is, a large number of through holes 22 with a diameter φ of about 50 μm are formed in the length direction.
It is a cylindrical member with a diameter of about 0.8 m and a length of 10 m, and its tip 4 has an apex angle of 600 m. Ro of the tip part 4,
It is machined into 15 conical shapes. Although not particularly shown in the drawings, the surface of the through-hole thin tube 23 is provided with a thin metal film of chromium to provide conductivity. A ceramic member having such a large number of through holes 22 is available from Pilot Precision Co., Ltd. as "ceramic through hole capillary".
It is supplied under the name of
An article about this was also published in the Nikkan Kogyo Shimbun on the 20th of May.

Also, rather than such non-conductive alumina powder,
If a similar shape is manufactured using metal powder or carbon powder, there is no need to attach a metal thin film to provide conductivity.

In such a configuration, the printing operation is similar to that described with reference to FIG. supply

Next, what is shown in No. 511H is a second embodiment of the present invention, in which a large number of recording electrodes 17 are arranged in parallel. In this case, an independent switching circuit 7 is connected to each recording electrode 17, and a control circuit 10 performs a switching operation corresponding to the image signal.

Next, a third embodiment of the present invention will be described based on FIG. The difference from the first embodiment shown in FIG.
4 is connected to a pressure device to apply static pressure higher than atmospheric pressure to the internal pressure of the ink volume s2. As a result, even if the fluid resistance of the first through hole 22 is somewhat high, the ink container 2
Since the internal pressure is high, the ink 1 flows out smoothly.

In particular, it is desirable to apply an appropriate pressure depending on the porosity of the through-hole thin tube 23 and the printing speed.

Note that the ink 1 may be supplied under pressure from an external ink supply pump instead of using air pressure.

Note that since the recording electrode 17 described above is extremely inexpensive, the print head 14 is made into a unit and the ink container 2 is
When the ink 1 is used up, the print head 14 can be replaced with a new one and used as a disposable one.

Effects of the Invention In the present invention, as described above, the recording electrode facing the counter electrode with the recording medium interposed therebetween is formed by a through-hole thin tube having a large number of through holes in the longitudinal direction. At the same time, the ink can be distributed smoothly,
As a result, ink is abundantly supplied to the tip of the recording electrode, and high print quality can be obtained even during high-speed printing, since there are many through holes through which ink flows out of the tip.

There is no occurrence of clogging due to ink drying, and it is possible to impart conductivity to the recording electrode by simply making the through-hole capillary itself conductive or attaching a thin metal film. be.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal cross-sectional side view showing the first embodiment of the present invention;
3 is a side view of the recording electrode, FIG. 4 is a rear view thereof, FIG. 5 is a vertical side view showing a second embodiment of the present invention, and FIG. 6 is a side view of the recording electrode. FIG. 7 is a vertical side view showing the third embodiment, and FIG. 7 is a vertical side view for explaining the printing method of the present invention that has already been proposed. DESCRIPTION OF SYMBOLS 1... Ink, 4... Tip part, 5... Recording paper (recording body), 6... Counter electrode, 17... Recording electrode, 22
...Through hole, 23...Through hole thin tube Applicant: Tokyo Electric Co., Ltd. Figure 32 Procedural Amendment (voluntary) March 10, 1985 1, Indication of Case Patent Application No. 1983-69485 2, Invention Name of printing device 4, agent 〒107 5, no date of amendment order 6, subject of amendment

Claims (1)

[Claims] 1. A recording electrode whose tip end has ink adhered to it and a counter electrode are arranged facing each other with a recording body interposed therebetween, and an electric field between these recording electrodes and the counter electrode exceeds a predetermined value. In the printing device, ink is ejected from the tip of the recording electrode to form an image on the recording medium when the recording electrode is pressed, and the recording electrode is formed by a through-hole thin tube having a large number of through holes formed in the length direction. A printing device characterized by: 2. The printing device according to claim 1, wherein the recording electrode has a conical tip. 3. The printing device according to claim 1, wherein the recording electrode is formed of a sintered compact made of a conductive material such as metal or carbon. 4. Claim 1, characterized in that the recording electrode is formed by a through-hole thin tube made of sintered metal oxide, and a metal thin film is attached to the surface of the through-hole thin tube to impart conductivity.
Printing device as described in section. 5. A recording electrode with ink attached to its tip and a counter electrode are placed opposite each other with a recording medium in between, and when the electric field between these recording electrodes and the counter electrode exceeds a predetermined value, the recording electrode In a printing device in which ink is ejected from the tip to form an image on the recording medium, only the tip of a through-hole thin tube in which a large number of through holes are formed in the length direction of the recording electrode is exposed. Store it in a sealed ink container,
A printing device characterized in that a static pressure equal to or higher than atmospheric pressure is applied to the inside of the ink container.