JPS60124260A - Wire dot printer - Google Patents

Abstract

PURPOSE:To achieve a quicker return by applying a film of manganese phosphate on the surface of an armature in a head to reduce wear of a sliding part of the armature with a holding spring or the like while facilitating the release thereof from the core. CONSTITUTION:In a print head of a wire dot printer, a film 20 of manganese phosphate is applied on the surface of an armature 8 to be driven by attraction with an electromagnet 5, preferably at the thickness of about 0.01-0.02mm.. The application thereof can be done at a low cost and with ease simply by dipping the armature 8 into a mixed solution of manganese primary phosphate and phosphoric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a wire dot printer in which a return operation of an armature in a print head drive section is quickly performed.

[Technical background of the invention]

FIG. 1 shows a print head drive section of a wire dot printer, in which a bottomed cylindrical yoke 3 is attached to a drive section case l via a terminal plate 2 by means such as bolt tightening. Further, a cylindrical nose portion 4 is provided at the center of the drive unit case l and extends in a direction opposite to the yoke 3.

Ru. Above 'IL6! The second stone 5 is composed of a self-sufficient iron core 6 that is self-sufficient on the inner bottom surface of the yoke 3, and a coil 2 that is wound around the self-sufficient iron core 6. Also, the open end hβ of the yoke 3
A base end of an armature 80 corresponding to each electromagnet 5 is arranged. These armatures 8 are positioned by armature guide plates 9, with each tip positioned near the center of the yoke 3. Further, a circular hole is provided at the center of the bottom of the yoke 3, and a wire guide plate IO is attached so as to close this circular hole. The wire guide plate IO is provided with a wire insertion hole 1'l corresponding to each electromagnet 5, and a dot wire 12 is inserted into each insertion hole 11.

The tip of each dot wire 12 reaches the tip of the nose portion 4 and is rotated around a platen (not shown), and the base end of the dot wire 20 is brought into contact with the aperture arm 8 by a coil spring 13. Therefore, the upper helical spring I3
has the full function of a return spring that pulls the armature 8 away from the fixed iron core 6 together with the dot wire 2.

On the other hand, a cap 14 is placed on the amateur guide 9, and a holding part t5 made of a leaf spring is placed above the cap 14, and the yoke 3, the amateur guide 9, and the cap 14 are integrally held together by this holding member 15. has been made into

Further, an armature pressing spring 16 made of a leaf spring is inserted between the amateur guide 9 and the cap 14, and this pressing spring 16 holds one end of each armature 8 pressed against the open end of the yoke 3. .

Furthermore, a positioning pin 12 is protruded from the center of the inner surface of the cap 14, and a stopper 18 made of an annular plate is attached to the pin 12.

This stopper 18 is designed to receive the reaction force of the coil spring 13 by bringing the tip of each armature 8 into contact with the side opposite to the dot wire I2. A rare dual film 19 of about .05 m is inserted. This is to prevent residual magnetic flux from existing between the armature 8 and the one-leg iron core 6 even after the electromagnet 5 is energized, preventing the armature 8 from returning. It is inserted into the S air circuit formed by the path of Amateur 3 and Amateur 8.

In the above configuration, when the coil 2 of the electromagnet 5 is energized, a magnetic path is formed along the path of the fixed iron core 6, the yoke 3, and the armature 8, and the armature 8 is attracted to the fixed iron core 6 and rotates. Therefore, the tip of the armature 8 presses the dot wire 20, and the tip of the dot wire 20 protrudes beyond the tip of the nose portion 4 to print dots on the printing paper wound around the platen. Further, when the current to the coil 2 is cut off, the dot wire 12 and the armature 8 are restored by the fill spring 13.

[Problems with background technology]

The armature pressing spring 16 is for pressing the rotation fulcrum part of the armature 80 so that the armature 8 can be rotated stably. On the other hand, the armature 8 is generally made of a soft magnetic material with good magnetic properties, but the sliding part, especially the contact part with the presser spring 16, is subject to severe wear, and as the wear progresses, the presser force by the presser spring 16 becomes weaker. This weakens the rotary action of the armature 8 and causes unreliable rotation of the armature 8, causing a drop in printing quality such as missing dots and uneven printing.

Furthermore, although the rare dual film 19 is a film made of a non-magnetic material, for example, a synthetic resin, the sliding part of the armature 8 is worn and abrasion powder is generated, which enters between the armature 8 and the rare dual film 19. There is a risk that the film 19 may be damaged. In such a situation, even after the electromagnet 5 is energized, the residual magnetic flux between the armature 8 and the fixed iron core 6 will prevent the armature 8 from returning.

Therefore, as a measure to prevent the armature 8 from wearing out,
It is possible to apply lubricating oil to the sliding parts, but since the armature 8 moves at extremely high speed, low-viscosity lubricating oil will scatter, and high-viscosity lubricating oil will prevent the armature 8 from moving at high speed. This is undesirable in any case as it will hinder the operation.

Furthermore, as a wear prevention measure, it is possible to apply a nitrided film or a hard film to the surface of the armature 8 by plating, but both are expensive and ID, and if the film is too hard, it will cause damage to the I6. This can cause problems such as wear on both sides.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to quickly return the armature in the lateral movement part of the print head, and to prevent the sliding of the armature and the pressing springs etc. that come into contact with it. An object of the present invention is to provide a wire dot printer that stabilizes the operation of an amateur by preventing wear of moving parts.

[Summary of the Invention] In order to achieve the above object, the wire dot printer of the present invention is characterized in that a manganese phosphate film r is deposited on the surface of the armature in the print head drive section.

And because of the above-mentioned manganese phosphate film, the presence of residual magnetic flux between the armature and the fixed iron core prevents the armature from returning to its original position? This can be prevented and amateurs can quickly recover. It also prevents wear on the sliding part of the armature, and the rotation forks of the armature. There is no fear of wearing out the presser spring, the operation of the armature can be made redundant, and the above-mentioned coating can be applied at low cost.

[Embodiments of the invention]

FIG. 2 shows one embodiment of the present invention, and the same parts as in FIG. 1 are given the same reference numerals and detailed explanations are omitted.

Similar to FIG. 1, FIG. 2 shows the print head drive section of a wire dot printer, but a manganese phosphate film 20 with a thickness of o
, oi-'o, approximately 02m.

Since the manganese phosphate film 20 has excellent wear resistance and low contact resistance, it is possible to prevent the sliding parts of the armature 8, for example, the parts in contact with the armature pressing spring 16, from being worn out. Further, the pressing spring 16 is not so hard as to cause wear. In addition, the manganese phosphate film 20 is microscopically a porous crystalline substance, and therefore can be impregnated with lubricating oil and has a large lubricating oil retaining ability. In other words, there is no risk of the lubricating oil being scattered even by the high-speed operation of the armature 8.

The formation of the manganese phosphate film 20 is performed using primary phosphoric acid '77 Ga7 (Mn (HI PO4) 1 ) and phosphoric acid CH, PU.
, ) can be done inexpensively and easily by simply immersing the amateur 8 in a mixed solution.

Moreover, since the manganese phosphate film 20 is also a non-magnetic material,
If a similar coating is applied not only to the armature 8 but also to the yoke 3↑ and the fixed iron core 6, a plurality of magnetic insulating layers can be inserted into the magnetic circuit. If the manganese phosphate film formed on the surface of the yoke 30 is impregnated with lubricating oil, the lubricating oil is constantly supplied to the sliding parts of the armature 8 by capillary action, thereby improving durability.

〔Effect of the invention〕

As described in detail above, according to the present invention, since a manganese phosphate film is applied to the surface of the armature in the print head drive section, the armature can be returned quickly without being affected by residual magnetism. This also prevents wear on the sliding parts of the armature, stabilizes the operation of the armature, and provides a wire dot printer that is inexpensive and has excellent durability.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a print head drive unit showing a conventional example.
Figure 2 is a partial sectional view of a print head drive section showing an embodiment of the present invention. 3... Yoke, 5... Electromagnet, 6... Fixed iron core,
8...Amateur, 12...Dot wire, 2o・
...Manganese phosphate film. Applicant's agent Patent attorney Suzu υ, Takehiko Figure 1 Figure 2 Commissioner of the Patent Office Kazuo Wakasugi 1. Indication of the case Japanese Patent Application No. 1983-232285 2. Name of the invention Wire dot printer 3. Case of the person making the amendment Relationship with Patent applicant (356) Tokyo Electric Co., Ltd. 4, agent 5, engraving of voluntarily amended specification (content 1ζ unchanged)

Claims (1)

[Claims] In a wire dot printer, the armature is attracted and driven by a magnet, and the armature presses and moves the dot wire to print dots at the tip of the dot wire.The surface of the armature is coated with a manganese phosphate film. A wire dot printer characterized by: