JPS62122775A - Dot printer - Google Patents

Abstract

PURPOSE:To enable the sound of impact of the tips of printing wires against a platen to be effectively shielded, by providing a sound-shielding means through which the printing wires penetrate and which surrounds the vicinity of the tips of the printing wires in proximity to a recording paper set on the platen. CONSTITUTION:A printing head 5 is provided with a plurality of printing wires 7. A sound-shielding cover 8 as a sound-shielding means and an ink ribbon 9 are disposed between the head 5 and a platen 2. A surface of the cover 8 on the side on which the cover faces the platen 2 is formed in a substantially semi-arcuate shape. The cover 8 surrounds the vicinity of the tips of the wires 7, and end surfaces of the cover 8 on the platen 2 side are extended to the vicinity of the outer peripheral surface of the platen 2. With this construction, the sound of impact of the printing wires 7 on a platen 2 can be prevented from leaking to the outside of the cover 8.

Description

TECHNICAL FIELD The present invention relates to a dot printer that prints on recording paper on a platen by driving a printing wire using electromagnetic force.

BACKGROUND ART In a conventional shuttle-type printer, a print wire provided in a print head is projected by an electromagnetic force toward a direction i Printing is performed dot by dot by selectively colliding the tip of the printing wire onto the recording paper of the platen.

When printing with such a print head, the tip of the print wire collides with the platen, and the impact noise generated at this time is the main source of noise in printers.

Currently, no measures have been taken to prevent noise caused by the impact noise between the tip of the printing wire and the platen.

Therefore, there has been a need for a dot printer that can effectively isolate noise.

OBJECTIVES An object of the present invention is to provide a dot printer that solves the above-mentioned technical problems and is capable of effectively insulating impact noise between the tip of a printing wire and a platen.

Embodiment FIG. 1 is a perspective view of the vicinity of the platen 2 of a shuttle type printer 1 according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the printer 1. A body 3 of the printer 1 houses a platen 2, a print head 5 for printing on records # and 4 on the platen 2, and the like. The platen 2 is formed into a right cylindrical shape and is rotatable around a rotating shaft 50. . Recording paper 4
is conveyed by the conveyance roller 6a and comes into contact with the outer peripheral surface of the platen 2, and is further discharged to the outside of the machine body 3 by another conveyance roller 6b.

The print head 5 is arranged facing the platen 2. This print head 5 is equipped with a plurality of print wires 7. Between the print head 5 and the platen 2, a sound insulation cover 8 as a sound insulation means and an ink ribbon 9 are arranged in this order toward the platen 2. The surface of the sound insulating cover 8 facing the platen 2 is formed into a roughly semicircular arc shape. A sound insulating cover 8 and an ink ribbon 9 are attached to the side wall of the print head 5. The print head 5 is held by a carriage horn 10 as shown in Figure plS3. ~ The spear 10 has a guide rod 11 extending parallel to the axis of the platen 2.
a, llb is inserted. The guide rods 11a and llb are fixed at both i portions by support pieces 12a and 12b, respectively. On the opposite side of the carriage 10 from the platen 2,
A protrusion 13 is provided. A shaft hole 13a is formed in this protrusion 13.

An internal thread is carved into the inner peripheral surface of the shaft hole 13a. A threaded rod 14 parallel to the guide rod 11a and Ilb is inserted into this shaft hole 13a.
is inserted and placed. This threaded rod 14 is rotationally driven by a stepping motor 15.

By rotationally driving the threaded rod 14, the claw 10, and thus the print head 5, can reciprocate along the movement direction B along the guide rods 11a and Ilb.

FIG. 4 is a sectional view showing a driving mechanism 81 for the print wire 7 in the print head 5. As shown in FIG. As shown in FIG. 4(1), the drive mechanism 20a includes a U-shaped yoke 21, a leaf spring 22 whose base end is fixed to the end of the yoke 21, and an electromagnetic coil wound around the yoke 21. 23. The base end of the printing wire 7 is fixed to the i end (the upper end in FIG. 4(1)) of the leaf spring 22. When the electromagnetic coil 23 is excited, the leaf spring 22 is displaced in the direction of arrow F against the spring force of the spring 24. This allows the printing wire 7 to pass through the insertion hole 8 of the sound insulation cover 8.
a and is projected toward the platen 2. As a result, the tip of the printing wire 7 selectively collides with the recording paper 4 on the platen 2 via the ink ribbon 9, whereby printing is performed on the recording paper 4 dot by dot.

When the electromagnetic filter 23 is demagnetized, the spring force of the spring 24 displaces the leaf spring 22 in the direction opposite to the direction of arrow F, thereby causing the printing wire 7 to separate from the outer surface of the platen 2 and return to its original state. Return. Such electromagnetic coil 2
By repeating the excitation and demagnetization steps 3, the printing wire 7 is driven and displaced, thereby printing is performed.

The driving mechanism for the printing wire 7 may be of the type shown in FIG. 4(2) other than the method shown in FIG. 4(1). The drive mechanism 20b shown in FIG. 4(2) is similar to the drive mechanism vI2 shown in FIG. 4(1).
0 a and Mffl, and corresponding parts are given the same reference numerals. What should be noted is that this drive mechanism 2ob has a yoke 21.
A permanent magnet 25 is interposed therebetween.

Therefore, when the electromagnetic coil 23 is demagnetized, the leaf spring 22 is displaced in the opposite direction to the arrow F by the electromagnetic force based on the permanent magnet 25 against the spring force of the spring 24, and the end of the yoke 21 is displaced. It is in a state where it is magnetically attracted to the portion 21a. In this state, the electromagnetic coil 23 is excited so that magnetic flux is generated in a direction that cancels the magnetic flux of the permanent magnet 25. As a result, the leaf spring 22 is displaced in the direction of the arrow F by the spring force of the spring 24, whereby the printing wire 7 projects in the direction of the platen 2. By repeating such excitation and demagnetization of the electromagnetic coil 23, the printing wire 7 can be driven and displaced.

FIG. 5 is a sectional view of the vicinity of the sound insulation cover 8. The sound insulating cover 8 is made of a material with high damping properties, such as urethane rubber. A sound absorbing material 30 such as glass wool is adhered to the inner peripheral surface of the sound insulating cover 8. This allows the sound insulation function to be further improved. The sound insulation cover 8 surrounds the vicinity of the tip of the printing wire 7, and furthermore, the end surface of the sound insulation cover 8 on the platen 2 side extends to the vicinity of the outer peripheral surface of the platen 2. With this configuration, the printing wire 7
The impact sound generated when the platen 2 collides with the platen 2 can be prevented from leaking to the outside of the sound insulating cover 8.

Note that the sound absorbing material 30 may be omitted.

@Figure 6 is a sectional view of another embodiment of the sound insulating cover. This embodiment is similar to the previous embodiment, and corresponding parts are provided with the same reference numerals. It should be noted that the sound insulating cover 40 in this embodiment is provided for each printing wire 7. Such a configuration can further improve the sound insulation effect.

effect.

As described above, according to the present invention, since the print wire tip is covered and surrounded by the sound insulation means, the noise caused by the collision between the print wire tip and the platen during the printing operation of the printer can be effectively reduced. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the vicinity of the platen 2 of a shuttle type printer 1 according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the printer 1, FIG. 3 is a perspective view of the vicinity of the print head 5, and FIG. (1)
is the drive of the printing wire 7 (a diagram showing one structure 20a, FIG.
2) is a diagram showing another drive end 20b of the printing wire 7, FIG. 5 is a sectional view of the sound insulation cover 8, and FIG. 6 is a sectional view of the sound insulation cover 40 of the embodiment of the invention. 1... Printer, 2... Platen, 4... Recording paper, 5... Print head, 7... Print wire, 8, 40
... Sound insulation cover, 8a ... Insertion hole, 9 ... Ink ribbon, 20a, 20b ... Drive mechanism for printing wire 7, 30 ... Sound absorbing material agent Patent attorney Keiichi Shisan Figure 1 Figure 4 Figure 5 Figure 6 Procedural amendment document February 10, 1986

Claims (1)

[Claims] In a dot printer that prints on a recording paper on a platen by driving a printing wire by electromagnetic force, the printing wire is inserted and the tip of the printing wire is connected to the recording paper on the platen. A dot printer characterized in that a sound insulating means is provided closely surrounding the dot printer.