JPH01190461A - Impact dot head - Google Patents

Abstract

PURPOSE:To reduce noises scattered from the last surface of a printing driving member, by providing a hollow wall between a radiator that abuts on the outer peripheral surface of a bottomed cylindrical frame and a driving unit, and a shielding member made of an elastic material for shielding an opening at the surface opposite to the printing surface of said radiator. CONSTITUTION:A shielding member 24 for shielding a back opening of a radiator 18 has a groove provided in the outer periphery thereof, which groove is pressed and inserted in a stepped part of the radiator. A hollow wall is formed between the radiator and the last surface of a printing driving member, so that the vibrations generated on the last surface of the printing driving member are prevented from being directly transmitted to the radiator. Moreover, noises generated by a lever holder 13 are shut by the inner wall of the radiator 18 and the shielding member 24, thus remarkably reducing the noises scattered into the air. Since the shielding member 24 is made of an elastic material, the vibrations of the radiator 18 are attenuated, and the noises of the radiator can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an impact dot printer head.

[Conventional technology]

FIG. 4 is a schematic diagram showing a conventional head structure.

Print wire 42. When the drive coil 40 is energized, the lever set 41 rotates due to magnetic force, thereby being biased toward the printing surface 20 and forming dots on the printing medium. After printing is completed, the return spring 41 returns to the standby position. Such reciprocating movement of the printing wire 42 generates vibrations and generates noise. Among these vibrations, when the printing wire 42 collides with the damper member 42 when the printing wire 42 returns, the damper member 42 cannot absorb the vibration, and a large vibration is generated in the lever holder 43 of the damper holding member. In particular, the sound generated by the lever holder 43 at the last stage on the side opposite to the printing surface of the drive unit is directly radiated into the air, and thus becomes a large noise source.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to reduce the noise emitted from the rearmost surface of the printing drive member and to obtain a low-noise impact dot head.

[Means to solve the problem]

In order to solve the above problems, the impact dot head of the present invention includes: a bottomed cylindrical frame having a columnar iron core forming a drive coil and a solenoid on the inner surface of the bottom; a radiator that comes into contact with the outer peripheral surface of the bottomed cylindrical frame; An impact dot head characterized in that it has an empty wall between it and the drive unit, and a shielding member made of an elastic material that closes an opening on the opposite printing surface of the radiator.

[For production]

In the impact dot head configured as described above, the sound emitted from the rearmost surface of the drive unit on the side opposite to the printing surface is insulated by the inner wall of the radiator and the shielding member that closes the opening on the side opposite to the printing surface of the radiator, and The sound radiated inside is significantly reduced. In addition, since the shielding member is made of an elastic material and is fixed to the radiator, the vibration of the radiator is attenuated and the noise generated from the radiator can be reduced, making it possible to obtain a low-noise impact dot. Can be done.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1st
The figure is a sectional view showing one embodiment of the present invention, and FIG. 2 is a perspective view.

The configuration of this embodiment will be explained based on FIG. 1. This embodiment has two stages of drive units, including a two-stage drive unit 22 on the side closer to the printing surface and an R-stage drive unit on the far side. Two-stage drive unit 22 and R-stage drive unit 23
Since the components are basically the same, the R stage drive unit 23
We will explain the components of

Symbol 1 in the figure is a lever set with printing wire 2, lever 3,
Consists of 4 amateurs. One end of the printing wire 2 is fixed to the lever 3, and the other end is guided and supported by a wire guide 15 and a tip guide 16. The lever 3 is joined to an armature 4, and the lever set 1 is rotatable around a fulcrum shaft 5. The lever set 1 is pressed against the damper rubber 12 by the spring force of the return spring 11 and is held at the standby position.

The armature 4, the core 6, the frame 7, the yoke A8, and the yoke B9 form a magnetic closed circuit, and when the coil 10 is energized, magnetic flux is generated in the magnetic closed circuit.

The fulcrum shaft 6 is held between a yoke A8 and a lever holder 13, and the damper rubber 12 is held by the lever holder 13. The lever holder 13 and other components are connected to the nose 17 by the spring force of a fixed spring 14.

The radiator 18 is in contact with the outer periphery of the frame 7, surrounds a part of the outer periphery of the frame 7 of the two-stage drive unit 22 and the entire outer periphery of the frame 7 of the R-stage drive unit 23, and is connected to the lever holder 13 and the fixed spring. It extends to the rear of the outer surface of 14 and is stepped inward at the rear opening.

The shielding member 24 that closes the rear opening of the radiator 18 has a groove on its outer periphery, and the groove of the shielding member is inserted into the stepped portion of the radiator 18 by press-fitting. Further, an empty wall is provided between the rearmost surface of the print drive member and the vibration of the rearmost surface of the print drive member is not directly transmitted.

The operation of the impact dot head configured as described above will be explained.0 When a drive current flows through the coil 10 from a head drive circuit (not shown), the core 6, frame 7,
A magnetic flux is generated with the yoke A8, yoke B9, and armature 4 forming a closed circuit, and the lever set 1 is attracted toward the core 6 by the magnetic force, and the printing wire 2 flies toward the printing paper 20.
The ink ribbon 19 collides with the printing paper 20 held on the platen 21 to print dots.

After printing, the printing wire 2 returns to the standby position after colliding with the damper rubber 12 due to the repulsive force of the platen 21 and the return spring force of the return spring 11.

Most of the energy of the drive current input to the coil 10 is converted into heat, which is radiated by the heat radiator 18.

In the above operation process, when the printing wire 2 returns and collides with the damper rubber 12, an impact vibration is generated, which is transmitted to each member and generates noise. The lever holder 13 holds the damper rubber 12 and receives the impact when the printing wire 2 returns, so the vibration is large and therefore the noise is large.
However, in the present invention, the sound generated by the lever holder 13 is insulated by the inner wall of the radiator 18 and the shielding member 24, and the amount of heat radiating into the air is significantly reduced. Furthermore, since the shielding member 24 is made of an elastic material, it can damp the vibrations of the radiator 18 and reduce the sound radiated by the radiator 18.

FIG. 3 compares the frequency analysis results of the radiated sound of a conventional impact dot head and a head configured as in the present invention, and shows that the head of the present invention has a large noise reduction at frequencies of 6 to 82 or higher. There was a total reduction effect of 8 dB (A).

Note that this embodiment does not control the present invention, and for example, even if the method of attaching the shielding member 24 to the heat sink 18 is adhesive, it does not depart from the scope of the present invention.

〔Effect of the invention〕

As explained above, the present invention uses the inner wall of the radiator and a shielding member made of an elastic material to insulate the sound generated at the rear end of the drive unit, which has a large radiated sound, and to significantly reduce the radiation into the air. Since the shielding member made of an elastic material attenuates vibrations, the sound radiated from the radiator is also reduced, making it possible to obtain a low-noise impact dot head.

In addition, there is no need to significantly change the conventional structure and basic performance is not affected, so it can be easily changed, and the shielding member can be installed easily by press-fitting, etc., making it easy to assemble. Are better.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an impact dot head showing an embodiment of the present invention, FIG. 2 is a partially sectional perspective view of the embodiment of FIG. 1, and FIG. FIG. 4 is a diagram showing a comparison of frequency analysis of radiated sound from conventional heads, and FIG. 4 is a cross-sectional view showing the conventional example. 1... Actuation piece 2 @-071y-A 13... Lever holder 14... Fixing spring 18... Heat sink 24... Shielding member and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Tsutomu Mogami (ffl11 people) Figure 1 Day 2 Prisoner 48

Claims (1)

[Claims] An impact dot head in which one or more drive units are stacked, comprising: a bottomed cylindrical frame having a columnar core forming a drive coil and a solenoid on the inner surface of the bottom; and an outer periphery of the bottomed cylindrical frame. An impact dot head comprising: a radiator that comes into contact with a surface; and a shielding member made of an elastic material that has an empty wall between the radiator and the drive unit and closes an opening on the opposite printing surface of the radiator. .