JPH0462541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printing apparatus that forms an image by selectively ejecting ink droplets using electrostatic means.

Prior Art Conventionally, ink dot printers that form images by ejecting ink droplets from nozzles have had a fatal defect in that the nozzles become clogged.

Therefore, in order to prevent ink clogging, there are conventional devices in which an image is formed by ejecting ink held in a slit instead of a nozzle. An example of such a product is Japanese Patent Application Laid-Open No. 56-4467 and Japanese Patent Application Laid-open No. 56-4467 as shown in Figure 6.
There is one described in Publication No. 42664.
That is, a large number of recording electrodes 2 are arranged within a slit 1 that holds ink, and a counter electrode 4 is arranged to face these recording electrodes 2 with a recording paper 3 interposed therebetween. A power source 6 is connected between the recording electrode 2 and the counter electrode 4, with a switching element 5 interposed between each electrode to generate a potential difference sufficient to cause ink to fly between the two. ing.

With such a configuration, when the switching element 5 is selectively turned on in response to a print signal, a potential difference is generated between each recording electrode 2. Then, the ink in the portion where the voltage is applied flies toward the counter electrode 4, thereby performing printing. At this time, since the ink is held within the slit 1, clogging of the ink is prevented. However, in this type of device, the distance between slit 1 and recording paper 3 is
Unless the distance is about 200 μm, stable ink flight cannot be achieved, and if the position of the slit 1 and the recording paper 3 is out of alignment, the recording paper 3 will be significantly stained.

For this reason, the applicant has applied for a printing device as shown in FIG. Such a device is described in Japanese Patent Application No. 69484/1984.
That is, a recording electrode 12 having a tapered tip is disposed opposite to the counter electrode 11 with the recording paper 10 interposed therebetween.
is formed into a member or shape that is impregnated with ink. This recording electrode 12 has an ink 13
The tip is inserted into an electrode hole 15 and the rear end is fixed to a wire 16 to be held. and,
A power source 18 is connected between the recording electrode 12 and the counter electrode 11 via a switching element 17 to generate a potential difference sufficient to cause ink to fly between them. Here, the details of the recording electrode 12 are as follows:
It is made by integrally molding fibrous materials into a bundle so as not to lose air permeability in the direction of the fibers.

In such a configuration, the ink 13 impregnates the recording electrode 12 and wraps around the tip thereof. Therefore, when the switching element 17 is turned on, a potential difference is generated between the recording electrode 12 and the counter electrode 11, and the ink 13 is ejected from the tip of the recording electrode 12. At this time, the ink 13 is supplied to the tip of the recording electrode 12 in just the right amount. In addition, since the tip of the recording electrode 12 protrudes, the electric field is concentrated on this portion, which improves the flight of the ink 13, and it becomes possible to arrange the recording electrode 12 and the counter electrode 11 at a certain distance. Therefore, the recording electrode 12 and the recording paper 1
Even if the positional relationship with 0 is out of order, the recording paper 10 will not be significantly soiled.

Note that FIGS. 8 to 11 show the recording electrode 12.
This shows a modification of . The one shown in FIGS. 8 and 9 has a large number of through holes 19 inside the recording electrode 12 extending from one end to the other, and is described in Japanese Patent Application No. 69485/1983. . on the other hand,
What is shown in FIGS. 10 and 11 is the recording electrode 1
A plurality of guide grooves 20 are provided on the outer circumferential surface of the guide groove 2 along the longitudinal direction thereof, and is described in Japanese Patent Application No. 60-69486. Both of these applications were filed by the applicant.

Problems to be Solved by the Invention However, the above-described structure in which the recording electrode 12 is impregnated with the ink 13 has a drawback that positioning of the recording electrode 12 is difficult. This is because if the center point of the tip of the recording electrode 12 and the center of the electrode hole 15 do not match, it is not possible to form a dot at an accurate position. teeth,
This is because it is difficult in terms of both component precision and manufacturing.

The present invention has been made in view of the above-mentioned problems, and is intended to facilitate accurate positioning of a recording electrode in which ink droplets are ejected from the tip of the recording electrode impregnated with ink by electrostatic means. The purpose is to obtain a printing device that can.

Means for Solving the Problems The present invention provides an ink 31 on the counter electrode 30 and the tip.
The recording electrodes 32 to which the recording electrodes 32 are attached are arranged opposite to each other with the recording body 33 in between. In a printing device in which an image is formed on a recording medium 33 by flying, the recording electrode 32 is formed into a member or shape that is impregnated with ink, and the tip of the recording electrode 32 is formed into a tapered shape, and the opposite electrode 30 A tapered holding hole 34 whose diameter becomes smaller as it approaches , is provided, and the tip of the recording electrode 32 is held in this holding hole 34 .

Function: Therefore, the tip of the recording electrode 32 fits into the holding hole 34 and only a part of it passes through the holding hole 34, and in this state, the recording electrode 32 fits into the holding hole 34.
be positioned securely. Therefore, accurate positioning of the recording electrode 32 is easily performed.

Embodiment of the Invention An embodiment of the present invention will be described based on FIGS. 2 to 5. Two guide shafts 41 are disposed horizontally within the housing-like case 40, and a carrier 42 is attached to these guide shafts 41 so as to be able to reciprocate in the left-right direction. A printing head 43 is placed on this carrier 42. A horizontally long counter electrode 44 is installed horizontally in the center of the case 40 so as to face the printing head 43. A tractor 46 is provided behind the counter electrode 44 to feed a recording paper 45 as a recording medium guided between the counter electrode 44 and the printing head 43. These tractors 46 are coupled with operating knobs 47 that protrude outward.

Here, details of the printing head 43 will be explained based on FIGS. 3 and 4. 48 ink inside
A housing-shaped ink tank 49 is provided to house the ink tank. This ink tank 49 has an opening divided into two by a dividing member 50 on the upper surface, one opening serves as an ink inlet 51 and is covered with a lid 52, and an electrode holding part 53 is attached to the other opening. ing. Here, the electrode holding section 53 has a structure that holds a plurality of recording electrodes 54 and supplies the ink 48 to these recording electrodes 54.
That is, a block-shaped holder 55 is fixed to the dividing member 50 at its mounting surface 56. The holder 55 is provided with a plurality of horizontal electrode holes 57 and vertical terminal holes 58 that communicate with each other inside. The electrode hole 57 opens from the surface opposite to the mounting surface 56. The electrode holes 57 are arranged in a row horizontally, and the terminal holes 58 are arranged in a row vertically. The recording electrode 54, which has a conductive coil spring 59 wound around its rear end and fixed thereto, is inserted into the electrode hole 57 from the spring 59 side. These recording electrodes 54 are made of a material that is impregnated with ink and is electrically conductive, and has a tapered tip. A conductive terminal 60 is embedded in the terminal hole 58 and extends until it comes into contact with the springs 59. Further, in the middle part of the recording electrode 54,
It fits into a through hole 62 formed at the upper end of an ink-impregnated body 61 whose lower end is located on the bottom surface of the ink tank 49 . A holding plate 63 that holds and positions the tip of the recording electrode 54 is fixed to the electrode holding section 53. This holding plate 6
3 is formed with a plurality of tapered holding holes 64 that are aligned with each of the recording electrodes 54 and match the shape of the tips of the recording electrodes 54. Further, the holding plate 63 is sloped so as to fall into the ink tank 49 from below the holding hole 64, and the holding plate 63 is attached to this sloped portion from directly below the holding hole 64. A reducing groove 65 reaching the lower end is formed. In addition,
In the holding plate 63, an R is marked at a portion where the slope begins.

As mentioned above, the printing head 43 is configured, and the printing head 43 is configured to be connected to the recording electrode 54.
is attached to the carrier 42 with the tip thereof and the counter electrode 44 facing each other.

On the other hand, a connector plate 67 is fixed to the holder 55 and has a plurality of connection holes 66 into which the upper ends of the terminals 60 fit. A plurality of lead cables 68 are connected to the connector plate 67, which are fixed to the connection holes 66 and connected to the terminals 60. These lead cables 68 are each connected to one end of a high voltage switch 69, and the other end of these high voltage switches 69 is connected to the counter electrode 44 via two divided high voltage power supplies 70 and 71. It is connected to the. The middle point of the connection between the high voltage power supplies 70 and 71 is grounded. Here, the connection state between the lead cable 68 and the counter electrode 44 is schematically shown in FIG.

In such a configuration, the ink 48 in the ink tank 49 is impregnated into the ink-impregnated body 61 and the recording electrode 54, and is supplied to the tip of the recording electrode 54. Therefore, the high voltage switch 6 is
9 is selectively turned on, a potential difference is generated for each recording electrode 54, and the ink 48 at the tip of the recording electrode 54 to which the voltage is applied flies toward the counter electrode 44. As a result, dots are formed on the recording paper 45, and printing is performed by a collection of these dots.

On the other hand, the dots formed on the recording paper 45 are always formed at accurate positions. This is because the positions of the recording electrodes 54 are regulated by the holding holes 64, so that all the recording electrodes 54 are positioned at preset correct positions. Moreover, such a recording electrode 5
4, the tip of the recording electrode 54 is placed in the holding hole 6.
4, it is easy to do. In addition, in this embodiment, since the recording electrode 54 is pressed against the holding hole 64 by the spring 59, there is no problem such as excessive force being applied from an undesirable direction, and the recording electrode 54 is pressed against the holding hole 64. forced by nature.

Further, since the spring 59 is formed of a conductive member, it functions as an electrical connection component for the terminal 60 and the like, and the number of components can be reduced.

Furthermore, since the spring 59 is fixed to the rear end of the recording electrode 54, the spring 59 and the recording electrode 54 are integrated.
It becomes easy to incorporate these into the device.

In addition, in implementation, a plate spring may be used as the spring 59, as shown in the schematic diagram of FIG.

Effects of the Invention In the present invention, a counter electrode and a recording electrode having ink attached to the tip thereof are arranged opposite to each other with a recording medium interposed therebetween, and when the electric field between these recording electrodes and the counter electrode exceeds a predetermined value, In a printing device in which ink is ejected from the tip of a recording electrode to form an image on a recording medium, the recording electrode is formed into a member or shape that is impregnated with ink, and the tip of the recording electrode is formed into a tapered shape. In addition, a tapered holding hole whose diameter decreases as it approaches the counter electrode is provided, and the tip of the recording electrode is held in this holding hole, making it easy to accurately position the recording electrode. , it is possible to easily manufacture the device and to perform high-quality printing, and when the recording electrode is pressed against the holding hole by a spring, the recording electrode can be held in a more natural state. The spring that presses the recording electrode against the holding hole is formed of a conductive member, and the rear end is connected to the recording electrode with a voltage. When connected to a circuit that applies , the spring can be used as a part of the electrical connection member, thus contributing to a reduction in the number of parts, and furthermore, allowing the recording electrode to be pressed into the holding hole. Using a conductive coil spring as a spring,
If this spring is wound around and fixed to the rear end of the recording electrode, the spring can be used as a part of the electrical connection member, and the device can be manufactured easily, thus reducing component costs. This has effects such as being able to reduce manufacturing costs.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional side view showing the principle of the present invention;
The figure is an overall perspective view showing one embodiment of the present invention.
The figure is a perspective view with a part of the printing head in section.
The figure is a vertical side view of the same, FIG. 5 is a vertical side view showing the connection state between the printing head and the counter electrode together with a modified example, FIG. 6 is a perspective view of one conventional example, and FIG. 7 is another example. 8 is a side view showing an example of a recording electrode, FIG. 9 is a rear view thereof, and FIG. 10 is a longitudinal side view.
The figure is a side view showing another example of the recording electrode, and FIG. 11 is a rear view thereof. 30... Counter electrode, 31... Ink, 32...
Recording electrode, 33... Recording body, 34... Holding hole.

Claims (1)

[Scope of Claims] 1. When a counter electrode and a recording electrode having ink attached to the tip thereof are arranged facing each other with a recording body interposed therebetween, and the electric field between these recording electrodes and the counter electrode exceeds a predetermined value. In a printing device in which ink is ejected from the tip of the recording electrode to form an image on the recording medium, the recording electrode is formed into a member or shape that is impregnated with ink, and the tip of the recording electrode is A printing device characterized in that a tapered holding hole is provided, the diameter of which decreases as it approaches the counter electrode, and the tip of the recording electrode is held in the holding hole. 2. Claim 1, characterized in that the recording electrode is pressed against the holding hole by a spring.
Printing device as described in section. 3. The printing apparatus according to claim 2, wherein the spring is formed of a conductive member and its rear end is connected to a circuit for applying voltage to the recording electrode. 4. The printing apparatus according to claim 2, wherein a conductive coil spring is used as the spring, and the spring is wound around and fixed to the rear end of the recording electrode.