JPH05270102A - Dot impact print head - Google Patents

Abstract

PURPOSE:To muffle noise during printing by providing an overhang part along a platen on the cover of a print head body, in such a manner that the overhang part encircles a part where printing wire hits an ink ribbon. CONSTITUTION:The head cover 1h of a print head 1 is allowed to hang over along the circumference of a platen 4 in such a manner that the cover extends all over the dot hammering part of an ink ribbon 2. That is, the head cover 1h is allowed to hang over so that it extends over the platen 4 on the platen 4 side. In addition, the hangover part encircles the part where the printing wire 1d presses the ink ribbon 2 and thereby, the ink ribbon 2 is caused to hit the platen 4 with a printing sheet 3. Consequently, a printing noise is prevented from leaking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head for a dot impact type printer which prints on a recording medium by selectively driving a plurality of print wires.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a dot impact type print head of this type has an armature 1c by applying a current to a coil 1b attached to a yoke 1a.
The print wire 1d brazed to the tip of the armature 1c is struck on the printing paper 3 with the platen 4 as a base via the ink ribbon 2 to print 1 dot, and the return spring 1f causes the armature 1c to move. When returned to the stopper 1e, the printed wire 1
The character d is separated from the ink ribbon 2 and a character is formed by repeating this operation. A head cover 11h that covers the entire print head 11 has a head tip portion that travels in a convex shape toward the platen 4 as shown in FIG.

[0003]

In this conventional dot-impact type print head, since the print portion is exposed on the platen side, the print sound leaks to the periphery of the print head and the noise of the printer itself is suppressed. Things were difficult.

[0004]

SUMMARY OF THE INVENTION The present invention utilizes an electromagnet to attract an armature to cause a piston to move a print wire attached to the tip of the armature. The tip of the print wire causes an ink ribbon to be mounted on a platen. In the dot impact type print head for printing by hitting on the printing paper, the projection of the shape along the platen is provided on the cover of the print head main body so as to surround the part where the print wire hits the ink ribbon.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 shows a dot impact type print head according to the first embodiment of the present invention and its surroundings.
Is a plan view including a partial cross-section, (b) is a vertical cross-sectional view, and FIG. 2 is a vertical cross-sectional view showing a second embodiment of the present invention.

The main structure of the first and second embodiments is as follows.
A dot impact type print head 1, an ink-impregnated cloth which is connected to the print portion for a long time by an ink ribbon, and an ink ribbon 2 which is pressed against the print sheet 3 by a print wire 1d to transfer the ink to the print sheet; And a platen 4 which is made of rubber and has a columnar shape and which serves as a base when the print ribbon 1d hits the ink ribbon 2 on the printing paper 3. Further, in the first embodiment, the printing is performed. The head cover 1h of the head 1 covers the print wire 1d and the ink ribbon 2 so that the platen 4 is covered therewith.
Overhangs along the circumference of.

In the dot impact type print head 1 of the first embodiment of the present invention as described above, when a current is applied to the coil 1b attached to the yoke 1a made of a magnetic material, the yoke 1a becomes an electromagnet and is also magnetic. The armature 1c made of material is sucked, the print wire 1d brazed to the tip of the armature 1c is driven toward the tip of the print head 1, and the tip of the print wire 1d jumps out from the main guide 1g, Push in the ink ribbon 2 located in front of the main guide 1g to
The printing paper 3 located on the front side of the sheet is struck on the platen 4 located on the front side. Immediately after that, the current passed through the coil 1b is cut off, and the armature 1c is returned by the return spring 1f to return to the stopper 1e. At that time, the print wire 1d is also returned to the surface of the main guide 1g. During this printing operation, the print wire 1d makes a sound of pushing the ink ribbon 2 and hitting the platen 4 together with the printing paper 3. The head cover 1h extends over the front surface of the print head 1, that is, on the platen 4 side so as to cover the platen 4, and the overhanging portion extends the print wire 1h.
d plays a role of reducing the amount of the printing sound that hits the platen 4 together with the printing paper 3 by pushing the ink ribbon 2 to the outside, and the noise of the printer itself, which occupies a large weight, can be suppressed.

Further, in the second embodiment shown in FIG.
A muffling cover 1k, which is formed separately from the head cover 1j, is provided as an overhanging portion that covers the print wire 1d and the dot portion of the ink ribbon 2 and suppresses the printing noise.

[0010]

As described above, according to the present invention, the print portion is covered with the head cover so that the print sound is leaked to the outside and the noise of the printer itself is suppressed.

[Brief description of drawings]

1A and 1B are diagrams showing a dot impact type print head and its periphery according to a first embodiment of the present invention, FIG. 1A is a plan view including a partial cross section, and FIG.

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention.

3A and 3B are diagrams showing a conventional example, in which FIG. 3A is a plan view including a partial cross section, and FIG.

[Explanation of symbols]

 1, 11 Print head 1a Yoke 1b Coil 1c Armature 1d Print wire 1e Stopper 1f Return spring 1g Main guide 1h, 1j, 11h Head cover 1k Noise reduction cover 2 Ink ribbon 3 Printing paper 4 Platen

Claims (2)

[Claims] 1. An electromagnet is used to attract the armature to cause a piston to move the print wire attached to the tip of the armature, and at the tip of the print wire, the ink ribbon is struck on the printing paper using the platen as a base. In a dot impact type print head for printing, a dot impact type print head characterized in that a protrusion of a shape along the platen is provided on a cover of the print head main body so as to surround a portion where the print wire hits the ink ribbon. head. 2. The dot impact type print head according to claim 1, wherein the projecting portion is formed by a housing separate from the cover of the print head main body.