JPS63295271A - Dot printer - Google Patents

Abstract

PURPOSE:To eliminate dot-type impact forces, ensure favorable heat dissipation from magnetic coils and a uniform ink film thickness and contrive higher printing quality, by selectively driving a plurality of needles having tip parts located at a magnetic ink film formed in a magnetic field slit, and providing the magnetic coils on the upper side of magnetic poles. CONSTITUTION:When a needle magnet 11 is energized in a pulsed manner based on a printing command, a magnetic ink 22 adhered to a tip part 17 of a needle 15 driven is adhered to a recording paper, forming a dot. Upon returning to an original position, the tip part 17 is again located in a magnetic ink film 24, and is wetted by the ink 22. With the operations repeated, printing is conducted in a noiseless manner. A magnetic coil 18 is located on the upper side of a magnetic pole 20, so that the heat generated by the coil is dissipated into the surrounding air, and a rise in temperature can be made small. In this way, the thickness of the magnetic ink film 24 formed in a magnetic field slit 19 is fixed, printing quality is enhanced, line breakage accidents are prevented from occurring in the coil 18, and it is made easy to find deterioration or breakage of the coil.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a dot printer in which dots are formed on a recording section by selectively driven needles, and characters or figures are formed by a collection of these dots. be.

Conventional technology Conventionally, there are two types of dot printers that use needles: one that uses an ink ribbon and one that uses pressure-sensitive paper. Both types utilize kinetic energy based on the movement of the needle. This causes the needle to collide with the recording section.

Problems to be Solved by the Invention In such impact type dot printers, there is a problem in that the noise during printing is extremely loud.

Means for solving the problem A magnetic field slit formed by magnetic poles is connected to an ink supply unit that supplies magnetic ink, and a plurality of needles are provided with their tips positioned on the magnetic ink film formed in the magnetic field slit. The needles were selectively driven by the head, and an electromagnetic coil was provided so as to be magnetically coupled to the magnetic pole and positioned above the magnetic pole.

Since a magnetic ink film is placed at the tip of the needle that is driven selectively, ink adheres to the tip of the driven needle, and when the tip comes into contact with the recording section, the impact force is removed. Dots can be formed without generation,
As a result, letters or figures can be formed with low noise, and since the electromagnetic coil that is magnetically coupled to the magnetic pole is positioned above the magnetic pole, the heat of the electromagnetic coil can be effectively dissipated. This makes it possible to keep the thickness of the magnetic ink film constant and prevent uneven printing quality.

Embodiment of the Invention First, a recording paper 2 serving as a recording section is wound around a platen 1, and in front of the platen 1 is a carriage that reciprocates along a guide shaft 3 installed parallel to the platen 1. 4 are provided. A drive wire 5 is connected to the second carriage 4, and the drive wire 5 is wound around a drive pulley 7 of a carriage motor 6 and a driven pulley 8 spaced apart from the drive pulley 7.

A needle head 9 and an ink film forming body 10 are attached to the carriage 4. The needle head 9 has a head portion 12 in which a plurality of needle magnets 11 are arranged, and a movable iron piece 13 is rotatably attached to each of the needle magnets 11. The head of a needle 15, which is biased by a return spring 14, is in contact with these movable iron pieces 13. These needles 15 are, for example, nine in number, and the needle guide 1
6, and their tips 17 are arranged in a vertical line.

Next, the ink film forming body 10 has an electromagnetic coil 18 above it, and side walls 21 integral with magnetic poles 20 facing each other and forming a magnetic field slit 19 are coupled to both ends of the electromagnetic coil 18. There is. The magnetic pole 20 extends downward, and its tip portion protrudes into an ink replenishment chamber 23 serving as an ink supply section that stores magnetic ink 22. The position of the ink supply store 23 is determined so that a magnetic ink film 24 is formed over the entire magnetic field slit 19 by energizing the electromagnetic coil 18 . Furthermore, the positions of each part of the magnetic pole 2o are set to A, B, and C.
, D, the magnetic field slit 19 at those positions
The magnetic field strength at is given a magnetic gradient such that it becomes stronger as it goes from D to A. Therefore, the magnetic ink film 24 within the magnetic field slit 19 is formed in a state where the influence of gravity is eliminated.

In such a configuration, when printing is not performed, the electromagnetic coil 18 is not energized, so there is no magnetic ink 22 within the magnetic field slit 19, and therefore, the magnetic field slit 19 is blocked by the scum formed due to evaporation. It never gets clogged. During printing, since the electromagnetic coil 18 is energized, the magnetic ink 22 is attracted into the magnetic field slit 19 and forms a magnetic ink film 24 . At this time, since the tip 17 of the needle 15 exists within the magnetic ink film 24, the tip 17 is wetted with the magnetic ink 22.

Then, the needle magnet 11 is energized in a pulsed manner based on the print command, and as a result, the driven needle 15 moves toward the recording paper 2, and its tip end 1
7 to contact the recording section 2 and return. This contact causes
The magnetic ink 22 that had adhered to the tip 17 adheres to the surface of the recording paper 2, forming a dot. Then, the tip 17 of the needle 15 that has returned to its original position is again exposed to the magnetic ink film 2.
4 and is wetted with magnetic ink 22. By repeating this process, printing can be performed without noise.

Since the electromagnetic coil 18 is located above the magnetic pole 20, even if the electromagnetic coil 18 generates heat, the heat is radiated to the surrounding air, thereby suppressing the temperature rise of the electromagnetic coil 18. As a result, the thickness of the magnetic ink film 24 formed in the magnetic field slit 19 is constant, and printing quality is improved. Furthermore, the occurrence of an accident in which the electromagnetic coil 18 is cut is also prevented. In addition, deterioration or damage to the electromagnetic coil 18 can be easily detected.

Furthermore, since the electromagnetic coil 18 is located near the magnetic field slit 19, the magnetic path between the electromagnetic coil 18 and the magnetic field slit 19 can be shortened, the magnetic resistance therebetween is reduced, and the magnetic efficiency is improved. However, it is possible to reduce the amount of current applied to the electromagnetic coil 18 and the number of turns required to form the magnetic ink film 24, thereby reducing the amount of heat generated. Furthermore, the ink film forming body 10 including the electromagnetic coil 18 can be formed in a small size, and the size and weight can be reduced.

In addition, in the above embodiment, the tip portion 1 of the needle 15
7 is inside the magnetic ink film 24, but in practice, it may be placed slightly apart on the opposite side from the recording paper 2, as shown in FIG. In this case, the magnetic ink film 24 acts just like an ink ribbon.

Effects of the Invention As described above, the present invention communicates a magnetic field slit formed by magnetic poles with an ink supply unit that supplies magnetic ink, and positions a tip part on the magnetic ink film formed in this magnetic field slit to generate a plurality of magnetic ink films. Needles are provided, these needles are selectively driven by the head, and an electromagnetic coil is provided that is magnetically coupled to the magnetic pole and positioned above the magnetic pole, so that the needles are selectively driven. Since a magnetic ink film is placed on the tip of the needle, ink adheres to the tip of the driven needle, and when the tip comes into contact with the recording section, a dot is created without any impact force being generated. This allows characters or figures to be formed with low noise.Also, since the electromagnetic coil magnetically coupled to the magnetic pole is located above the magnetic pole, the electromagnetic coil This makes it possible to effectively dissipate heat, thereby making it possible to keep the thickness of the magnetic ink film constant and to prevent uneven printing quality.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view, Fig. 2 is a perspective view of the main part, Fig. 3 is a partially cutaway side view, and Fig. 4 is a plan view thereof. FIG. 5 is a graph showing the relationship between the magnetic field slit position and the magnetic field strength, and FIG. 6 is a sectional view showing a modification.

Claims (1)

[Claims] A magnetic pole forming a magnetic field slit that communicates with an ink supply unit that supplies magnetic ink, a plurality of needles whose tips are positioned in the magnetic ink film formed in the magnetic field slit in a returned state, and driving these needles. 1. A dot printer comprising: a head portion having magnets arranged thereon; and an electromagnetic coil magnetically coupled to the magnetic pole and located above the magnetic pole.