JPH0259063B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention This invention relates to a dot printer.

Technical background of the invention and its problems Conventional dot printers impact a needle on a platen using an electromagnetic armature and print on pressure-sensitive paper along the front of the platen, or press ink from an ink ribbon onto plain paper to print. It is something to do. In any case, since the needle impacts the platen, the impactor is high.

Recently, magnetic ink in the ink tank is drawn up between these magnetic poles by facing the front surface of the recording paper, and a needle that penetrates the sucked up magnetic ink layer is brought into contact with the recording paper.
It reduces the printing pressure on the recording paper and reduces printing noise to a certain extent.

Purpose of the Invention The present invention has been made in view of the above points, and an object thereof is to provide a dot printer that can print without bringing the needle into contact with recording paper, and can therefore significantly reduce printing noise. This is the purpose.

Summary of the Invention This invention attracts magnetic ink in an ink tank between opposing magnetic poles and transfers this magnetic ink onto recording paper using a needle, but the stroke of the needle is limited to prevent it from touching the recording paper. The needle is slid toward the recording paper and stopped suddenly, and the inertia of the needle at this time transfers the magnetic ink attached to the tip of the needle onto the recording paper, thus significantly reducing printing noise. It is composed of

Embodiment of the Invention An embodiment of the invention will be described based on the drawings.
A carrier 3 on which a printing head 2 is mounted is slidably provided in a housing 1 and held by a carrier shaft 4 and a guide shaft 5. A cover 6 is provided on the upper surface of the housing 1, although only a portion thereof is shown. The print head 2 is comprised of a magnet case 8 containing a plurality of electromagnets 7 arranged in a ring shape and a guide frame 10 holding a plurality of needles 9. The needle 9 is formed with a stepped portion 9a that presses magnetic ink, which will be described later, and a narrow-diameter tip portion 9b located at the tip of the stepped portion 9a. The armature 11 is fixed to the rear end of the needle 9, urged in the return direction by a needle spring 12, and pressed against a back stopper 13. This armature 11 is attracted to the core 14 from the return position where it contacts the back stopper 13, and its stroke is determined by the contact with the suction surface 15 of the core 14.
The stroke of the needle 9 fixed to the armature 11 is determined so that it does not come into contact with recording paper 36, which will be described later. Guide frame 10
Needle guide 1 to align needle 9
6 and 17 are fixed, and magnetic plates 19 coupled to both poles of a magnetic ink attraction coil 18 are fixed to both ends of this guide frame 10.
Magnetic poles 21 facing each other with a slit 20 in between are continuously formed at the tip of the needle 9, and the tip of the needle 9 protrudes from the slit 20.

Furthermore, a flat ink tank 22 and a cartridge 23 are detachably attached to the print head 2. A magnetic pole 21 is placed on the top surface of the ink tank 22.
A small slit-like hole 24 into which the lower end of the slit is inserted and a through hole 25 located in the center are formed continuously, and
An opening 27 for replenishing magnetic ink 26 is formed. A permanent magnet 28 facing the lower end of the magnetic pole 21 is fixed to the lower surface of the ink tank 22 . A tube 29 that fits into the opening 27 is formed on the lower surface of the cartridge 23, and an opening 30 is formed at the lower end of the tube 29 to discharge the magnetic ink 26 inside. A plug 31 that closes the opening 30 is urged downward by a spring 32 and is fitted so as to be movable up and down. Further, a rod 33 is formed protruding from the lower surface of the stopper 31, and a plurality of notches 34 are formed on the outer periphery. The radius of the circle connecting the bottoms of these notches 34 is larger than the radius of the opening 30.

Furthermore, a recording paper 36 is provided in front of the print head 2 and is fed by a paper feed roller 35.

In such a configuration, when the magnetic ink attraction coil 18 is energized, the magnetic pole 2 is turned on as shown in FIG. 6a.
The magnetic ink 26 in the ink tank 22 is attracted by the magnetic flux generated between the needles 9 and 1, and the tip of the needle 9 is wetted with the magnetic ink 26. When the specified electromagnet 7 is excited, the needle 9 slides together with the armature 11 and approaches the recording paper 36 as shown in FIG. As shown in FIG. 6c, the magnetic ink 26 attached to the tip of the needle 9 is transferred by inertia to the recording paper 36 to form a dot. Therefore, the needle 9 is connected to the recording paper 36 and the magnetic pole 3.
7, and printing noise can be significantly reduced.

Further, the magnetic force of the magnetic ink attraction coil 18 is constant, and the magnetic ink 26 in the ink tank 22 is replenished from the cartridge 23 according to the amount consumed, so it is maintained at a constant level. The layer level is also constant, and there is no situation where the magnetic ink 26 does not reach the upper needle 9. Further, since it is present in the cartridge cartridge 23, there is no need to manually replenish the ink tank 22, which saves time and effort.

When printing is finished, the magnetic ink suction coil 18
Although the magnetic ink 26 is easily stuck between the magnetic poles 21 due to surface tension, it is collected into the ink tank 22 by the force of the permanent magnet 28 with a weak force.

Effects of the Invention Since the present invention is configured as described above, the magnetic ink attracted between the magnetic poles is transferred from the needle to the recording paper, but by simply bringing the needle close to the recording paper without contacting it, the ink is transferred from the needle due to inertia. Magnetic ink can be transferred to recording paper, and therefore,
This has the effect of significantly reducing printing noise.

[Brief explanation of drawings]

The drawings show one embodiment of the invention.
The figure is a perspective view showing the overall configuration with a reduced size and a part cut away, Figure 2 is a plan view, Figure 3 is a longitudinal side view, and Figure 4 is a perspective view showing the overall configuration.
The figure is an exploded perspective view, Figure 5 is an enlarged front view with a portion cut away and shows the magnetic pole inserted into the ink tank, and Figure 6 is a partially enlarged plan view showing the state of magnetic ink transfer. be. 9...Needle, 18...Magnetic ink attraction coil, 20...Slit, 21...Magnetic pole, 22...
Ink tank, 26...magnetic ink, 36...recording paper.

Claims (1)

[Claims] 1. Magnetic poles are magnetically coupled to a magnetic ink attracting coil and face each other with slits made, and the lower ends of these magnetic poles are inserted into an ink tank containing magnetic ink and immersed in the magnetic ink, and the magnetic ink is absorbed by the magnetic force. A plurality of needles are slidably provided between the magnetic poles, and each needle is provided with a step portion that captures the magnetic ink attracted between the magnetic poles and a tip portion with a small diameter, and that transfers the magnetic ink onto the recording paper. The strokes of these needles are determined so that they approach the recording paper in a non-contact state, and when the needles suddenly stop, the magnetic ink at the tips of the needles is transferred to the recording paper by inertia. dot printer.