JPH0542349B2 - - Google Patents

Description

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

Conventional technology Conventionally, so-called inkjet printers, which form images on a recording medium by ejecting liquid ink droplets from a nozzle, have been known to produce less noise during printing and to perform multicolor printing compared to other printing methods. Many inventions have been made and improvements have been made for reasons such as being advantageous in terms of running costs and the like. 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 instead of a nozzle that is prone to clogging. However, an electric field is applied between opposing electrodes facing this opening to cause the 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, JP-A-54-
As seen in Japanese Patent Application Laid-open No. 23534 and Japanese Patent Application Laid-open No. 159355/1983, ink is guided to the tip of a needle-like member along its outer periphery, and the ink is caused to fly by an 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. That 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 normal ink.

In order to solve these problems, the applicant invented a printing device of the type shown in FIG. 8, and
A patent application was filed. 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. Then, the switching circuit 7
A control circuit 10 that generates a control signal according to an image signal is connected to.

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

(1) Metal granules formed by casting without losing air permeability. (2) Conductive granules such as transition metal oxides sintered. (3) Conductive particles mixed with carbon fine particles. Breathable foam molded plastics Among these, (1) and (2) are a collection of irregularly shaped particles, and the pores formed between the particles communicate three-dimensionally. In addition, there are some that have a substantially similar structure regarding (3).

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, and the tip reaches the tip 4. 4, the ink 1 is ejected toward the recording paper 5.

Although printing is performed according to such a principle, since the tip portion 4 of the recording electrode 3 is exposed to the outside, it is inevitable that the ink 1 in that portion evaporates. However, since the tip portion 4 has a high degree of fluid communication with the ink 1 in the ink container 2, the concentration of the ink 1 can be well uniformed.
No slag of ink 1 is generated on the tip 4.

In this way, this type of printing device is a dramatic advance over conventional technology, but in order to increase the printing speed, it is necessary to reduce the amount of ink 1 supplied without the risk of droplets. This is something that needs to be increased. That is, it is desirable that the recording electrode 3 has a high ability to retain the ink 1 and has low fluid resistance.

However, when the recording electrode 3 is made of a material with good ink flowability, bleeding of the ink 1 at the exposed portion of the recording electrode 3 at the tip 4 is unavoidable. Due to this bleeding of the ink 1, the ink 1 tends to flow downward over a long period of time, staining the hands and the surrounding area.

Means for Solving the Problems A surplus ink storage chamber is formed with an opening located below the surface where the recording electrode is exposed.

Function The ink flowing out from the tip of the recording electrode flows down the surface where the tip is located, but there is an excess ink storage chamber in the direction of the flow.
Ink does not enter the surplus ink storage chamber through the opening and stain the area around the printer head.

Embodiment A first embodiment of the present invention will be described based on FIGS. 1 to 3. Components that are the same as those described in connection with FIG. 8 are designated by the same reference numerals, and description thereof will be omitted. First, the printer 11 has two (first
Guide shaft 1 (only one is shown in the figure)
2 is provided horizontally, and a carrier 13 is attached to this guide shaft 12 so as to be able to reciprocate from side to side. A printing head 14 is placed on this carrier 13. Further, in the center of the printer 11, a counter electrode 6 facing the printing head 14 is horizontally attached. Behind this counter electrode 6 is a tractor 1 that feeds recording paper 5 as a recording medium.
5 is provided. An operating knob 16 projecting outward is coupled to the tractor 15.

On the upper surface of the carrier 13, a connector 17 provided in a slit-shaped recess is installed, and two head guide shafts 18 protruding upward are provided. and,
The printing head 14 consists of a printer head 19 and an ink tank 20 for supplying ink 1 to the printer head 19. A connector 21 connected to the connector 17 is formed on the printer head 19. The front end portions 4 of four recording electrodes 3 are formed to protrude from the front surface. Air holes 22 are formed above each of these tip portions 4 . Further, an opening 23 having a width wider than the arrangement width of the tip portions 22 is formed below the tip portion 4, and this opening 23
is in communication with the surplus ink storage chamber 24. Such an opening 23, the tip 22, and the air hole 22
A protruding edge 25 surrounding the cap 25 is formed protrudingly, and a cap 26 is detachably attached to the protruding edge 25. Further, a chamber 2 in which the recording electrode 3 is housed
An ink supply hole 28 and an air supply hole 29 communicating with the chamber 27 are formed on the upper surface of the cartridge 7 .

Next, the ink tank 20 is provided with an impregnating material 30 that is inserted through the ink supply hole 28 and comes into contact with the recording electrode 3 to supply ink 1, and a cylinder that fits into the air supply hole 29 is provided. A shaped air hole 31 is formed.

In this configuration, an electric field with a potential sufficient to fly the ink 1 between the recording electrode 3 and the counter electrode 6 is generated in synchronization with the movement of the carrier 13, and the ink 1 is flown in the form of particles for recording. Form dots on paper 5. By repeating this process, letters and figures are formed from a collection of dots.

In this way, since the ink 1 receives a moving force from the electric field, the ink 1 that was not able to fly
Some of the ink 1 flows out onto the surface of the printer head 19, and in some cases, the ink 1 flows down. This flowing ink 1 flows from the opening 23 into the surplus ink storage chamber 24, so that the ink 1 flows into the printer head 1.
There is nothing that goes around below 9. Therefore, the ink 1 does not stain the surrounding area.

Further, the widthwise dimension of the opening 23 is the width of the recording electrode 3.
Since the width of the array is larger than the array width of , surplus ink can be captured reliably.

Next, a second embodiment of the present invention will be described based on FIG. The same parts as in the previous embodiment are designated by the same reference numerals, and the description thereof will be omitted (the same applies hereinafter). In this example,
Grooves 32 are formed as spaces located on both sides of the arrangement width of the recording electrodes 3, and these grooves 32 are communicated with the openings 24.

Therefore, in this case, even if ink 1 leaks from the recording electrode 3 as ink dripping, the ink 1
This effectively captures and guides the ink 1 to the surplus ink storage chamber 24, and reliably prevents the ink 1 from moving in the lateral direction.

Next, FIG. 5 shows a third embodiment of the present invention, in which three colors of ink 1 can be used simultaneously. That is, three ink tanks 20 are provided in parallel, and the printer head 1 is arranged in correspondence with these ink tanks 20.
The interior of 9 is also independently separated to prevent color mixing. Three recording electrodes 3 are used for each color, and the tips 4 of each recording electrode 3 are arranged diagonally. A groove 32 serving as a space is formed between each color so as to separate the colors. The grooves 32 formed in this manner prevent color mixing.

Next, FIG. 6 shows a fourth embodiment of the present invention, in which the upper edge of the opening 23 of the surplus ink storage chamber 24 is chamfered 33. This chamfer 33 allows surplus ink to be guided to the surplus ink storage chamber 24 in a good manner. Instead of this chamfer 33, an arcuate portion may be formed.

Further, an ink discharge port 34 is formed on the back side of the surplus ink storage chamber 24, and this ink discharge port 34 is closed with a stopper 35 so as to be openable.

Further, a lead wire 36 electrically connected to each recording electrode 3 is inserted into the case of the printer head 19 and connected to the connector 21.

Further, the lower edge of the opening 23 is connected to a surplus ink storage chamber 24.
It is an inclined surface 37 inclined inwardly. Thereby, the ink 1 is guided well and the ink is captured reliably.

Next, a fifth embodiment of the present invention will be described based on FIG. In this embodiment, the surplus ink storage chamber 24
An impregnating material 38 is provided for impregnating and retaining the excess ink. By removing the stopper 35, extracting the impregnating material 38, and replacing it with a new one as needed, the ink 1 does not have to be treated as a liquid, and the process is easy to handle.

Effects of the Invention As described above, the present invention forms a surplus ink storage chamber in the printer head by positioning the opening below the part where the tip of the recording electrode is exposed, so that the ink flowing out from the tip of the recording electrode is The surplus ink is not captured in the storage chamber and does not flow downward, which makes it easy to handle without staining the surrounding area. By forming a space between the tips of the recording electrodes, it is possible to reliably capture ink even if there is any ink dripping.Furthermore, by forming a space between the tips of the recording electrodes, it is possible to easily capture the ink in case of multicolor printing. This has the effect that no mixing occurs.

[Brief explanation of the drawing]

Fig. 1 is a vertical side view showing a first embodiment of the present invention, Fig. 2 is an exploded perspective view thereof, Fig. 3 is a perspective view of the printer main body, and Fig. 4 is a view showing a second embodiment of the invention. 5 is a perspective view showing a third embodiment of the present invention, FIG. 6 is a vertical sectional side view showing a fourth embodiment of the present invention, and FIG. 7 is a perspective view showing a third embodiment of the present invention. FIG. 8 is a vertical cross-sectional side view showing an example of a conventionally proposed printing method. 1... Ink, 3... Recording electrode, 4... Tip, 5... Recording paper (recording body), 6... Counter electrode,
19...Printer head, 23...Opening, 24...
... Surplus ink storage chamber, 32 ... Groove (space), 3
3... Chamfer, 34... Ink discharge port, 35...
Plug, 38...impregnating material.

Claims (1)

[Scope of Claims] 1. A recording electrode having electrical conductivity and ink-impregnating property is formed, a counter electrode is provided that faces the recording electrode via a recording body, and an image is formed between the counter electrode and the recording electrode. In a printing device that forms an image by causing ink impregnated in the recording electrode to fly from the recording electrode toward the recording medium by applying a constant voltage according to a signal, the recording electrode is connected to the tip of the recording electrode. 1. A printing device comprising: a printer head that holds only a portion of the recording electrode exposed, and a surplus ink storage chamber having an opening below a surface where the tip portion of the recording electrode is exposed. 2. The printing device according to claim 1, wherein the upper corner of the opening of the surplus ink storage chamber is chamfered or arcuate. 3. A recording electrode having electrical conductivity and ink-impregnating property is formed, a counter electrode is provided that faces the recording electrode via a recording body, and a constant voltage is applied between the counter electrode and the recording electrode depending on the image signal. In a printing device that forms an image by causing ink impregnated in the recording electrode to fly from the recording electrode toward the recording medium by applying a voltage, the recording electrode is provided with only its tip exposed. forming a printer head for holding the recording electrode, forming a surplus ink storage chamber having an opening below the surface where the tip of the recording electrode is exposed, and impregnating the inside of the surplus ink storage chamber with ink; A printing device characterized by being provided with a material. 4 A recording electrode having electrical conductivity and ink-impregnating property is formed, a counter electrode is provided that faces the recording electrode via a recording body, and a certain amount of air is provided between the counter electrode and the recording electrode depending on the image signal. In a printing device that forms an image by causing ink impregnated in the recording electrode to fly from the recording electrode toward the recording medium by applying a voltage, the recording electrode is provided with only its tip exposed. A surplus ink storage chamber having an opening below the surface where the tip of the recording electrode is exposed is formed in the printer head, and an ink discharge port communicating with the surplus ink storage chamber is formed. and a printing device characterized in that the ink discharge port is freely opened and closed with a stopper. 5 A recording electrode having electrical conductivity and ink-impregnating property is formed, a counter electrode is provided that faces the recording electrode via a recording body, and a certain level of electrical conductivity is provided between the counter electrode and the recording electrode depending on the image signal. In a printing device that forms an image by causing ink impregnated in the recording electrode to fly from the recording electrode toward the recording medium by applying a voltage, only the tips of a large number of recording electrodes are exposed. forming a printer head for holding the recording electrodes by arranging them in parallel, and having an opening having a widthwise dimension larger than the array width of the recording electrodes below the surface where the tips of the recording electrodes are exposed; A printing device characterized in that an ink storage chamber is formed in the printer head. 6. A recording electrode having conductivity and ink impregnability is formed, a counter electrode is provided that faces the recording electrode via a recording body, and a certain amount of air is provided between the counter electrode and the recording electrode depending on the image signal. In a printing device that forms an image by causing ink impregnated in the recording electrode to fly from the recording electrode toward the recording medium by applying a voltage, a large number of recording electrodes of different colors are connected to the tips of the recording electrodes. forming a printer head that exposes only the recording electrodes and arranging and holding them in parallel; forming a space between the recording electrodes of different colors; and forming a space between the recording electrodes of different colors; 1. A printing device characterized in that a surplus ink storage chamber is formed in the printer head, the surplus ink storage chamber having a lower opening having a widthwise dimension larger than the arrangement width of the recording electrodes.