JPH04214364A - Wire dot-type printing head - Google Patents

Abstract

PURPOSE:To minimize noise of a wire dot-type printing head. CONSTITUTION:Front and rear printing head covers (head frame 14 and rear cover 15) are formed almost like a bowl using a highly vibration-damping material. Then the head frame 14 and the rear cover 15 are provided with their respective opening sides opposed to each other, and further, sound absorbing materials 21, 22 are arranged inside the mentioned members. Subsequently, an impact sound generated by the impact of an armature 9 with a core part 3 is reduced by the sound absorbing materials 21, 22. In addition, a vibration which vibrates and is transmitted through the head frame 14 and the rear cover 15 after being attenuated by the sound absorbing materials 21, 22, is attenuated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire dot print head that selectively drives a plurality of print wires to print on a recording medium.

0002

2. Description of the Related Art As a print head for printing characters, symbols, etc. using a plurality of print wires, there is a multi-core type print head that is small and capable of printing in Mincho typeface. In this type of print heads, those with high printing speed and high printing power capable of printing on a large number of sheets of copy paper have come to be used. However, serial printers equipped with print heads with high printing power generate a lot of noise during operation. For this reason, conventional serial printers of this type have an important responsibility to reduce noise, which conflicts with the demands for high speed and high printing power.

Noise generated from the print head is divided into printing sound and internal sound. The former is the sound generated when the print wire (hereinafter simply referred to as wire) hits the ribbon and print medium, and this sound is radiated into the air as it is, and the waves and vibrations generated in the platen are propagated into the air. It consists of sounds. As a method to reduce this printing noise,
Changing the shape and material of the platen is effective, and many results have already been achieved. On the other hand, the internal sound is the sound generated when the moving parts in the print head, such as wires and armatures, collide with the core part of the yoke. This sound is caused by vibrations generated in components such as the yoke propagating to the air outside the print head, and sound radiated directly into the space inside the print head from the collision surface of the yoke and armature, which is caused by the head frame and rear cover being emitted to the outside of the print head. It consists of sound that passes through and leaks out. Of these, the former is relatively high-frequency sound and does not contribute significantly to noise outside the printer because it is quickly attenuated within the printer's housing. However, the latter transmitted sound is difficult to attenuate in the printer housing and has a high noise level, so it has a large effect on noise outside the printer.

0004

[Problem to be Solved by the Invention] In the conventional print head, among the internal sounds generated by the collision between the core part of the yoke and the armature, the internal noise is radiated directly from the collision surface and leaks through the head frame, rear cover, etc. No soundproofing measures were taken to prevent sound, and serial printers using this print head had the problem of increased noise. In order to eliminate such problems,
Conventionally, attempts have been made to fill the area around the yoke and coil with silicon, etc., but while this method can attenuate the vibration sound propagating through the yoke to some extent, it has no significant effect on transmitted sound. You can't get it.

[0005]

[Means for Solving the Problems] A wire dot type print head according to the present invention has front and rear print head covers formed of a material with high vibration damping properties into a substantially bowl shape, with their opening sides facing each other, and A sound absorbing material is placed inside this print head cover.

[0006]

[Operation] The collision sound generated when the armature collides with the core is attenuated by the sound absorbing material, and furthermore, when it vibrates through the front and rear print head covers and is transmitted, the vibration is greatly attenuated.

[0007]

[Embodiment] An embodiment of the present invention will be explained in detail below with reference to FIG.

FIG. 1 is a sectional view of a wire dot type print head according to the present invention. In the figure, reference numeral 1 denotes a wire dot type print head (hereinafter simply referred to as print head) according to the present invention, and the wire driving section of this print head is constructed in the same manner as a conventional print head. Reference numeral 2 denotes a yoke of this print head 1. This yoke 2 is formed in an annular shape as a whole, and has a core portion 3 on the inner circumferential side to which an armature, which will be described later, is attracted.
A plurality of them are arranged in parallel along the circumferential direction. A coil 4 is provided in each of these core portions 3. A board 5 is provided with a circuit (not shown) for feeding power to the coil 4, and this board 5 is attached to the rear surface of the yoke 2. 6 is a magnet, 7 is a ring yoke,
Reference numeral 8 denotes a top plate, each of which is formed into an annular shape and is attached to the front surface of the yoke 2 in a stacked manner. An armature 9 for printing is attached to the top plate 8. The armature 9 has a spring disk 11 whose outer periphery is fixed to the top plate 8 and a block 10 is attached to the inner protruding piece, and a printing wire 12, which is integrally provided with the block 10. It is composed of an arm 13 and the like. This armature 9 is mounted with a block 10 facing the front surface of the core section 3, and normally (when the coil 4 is not excited) the block 10 is magnetically attracted to the core section 3 by the magnetic flux of the magnet 6. However, when the coil 4 is excited and the above-mentioned magnetic flux is canceled,
The block 10 is configured to be separated from the core portion 3 by the elastic force of the spring disk 11. block 10
When the wire 12 is separated from the core portion 3, the wire 12 protrudes forward of the yoke 2 and printing is performed. The wire driving section of the print head 1 is composed of the above-mentioned members.

14 is a head frame as a front print head cover of this print head 1, and 15 is a rear cover as a rear print head cover, each of which is formed entirely into a bowl shape from a material with high vibration damping properties. The head frame 14 and rear cover 15 are attached so as to sandwich and hold the above-mentioned wire drive section. That is, the head frame 14 has a bowl-shaped opening edge in contact with the front surface of the outer circumference of the spring disk 11, and the rear cover 15 has a bowl-shaped opening edge in contact with the rear surface of the substrate 5. Each is attached in this way. When the head frame 14 and rear cover 15 are attached to the wire drive section, the overall shape of the print head is approximately spherical with bulges provided at the front and rear. In addition,
A zinc-based alloy is used as a material with high vibration damping properties for forming the head frame 14 and the rear cover 15.

The head frame 14 has an opening 14a at the front end (bowl-shaped top) through which the wire 12 is passed.
A tip guide 16 is provided to hold the tip of the wire 12 in place.

Reference numerals 17 and 18 are intermediate guides for supporting the central portion of the wire 12 in the longitudinal direction, and these intermediate guides 17 and 18 are supported through a guide pole 19 that passes through the wire drive section. This guide pole 19 is fixed to the top of the rear cover 15 with screws 20.

21 and 22 are sound absorbing materials, the sound absorbing material 21 being inside the head frame 14 and in front of the armature 9, and the sound absorbing material 22 being inside the rear cover 15 and behind the board 5. Each side is filled. The sound absorbing material 21 is bonded to the inner surface of the head frame 14 and is provided within a range where it does not interfere with the operation of the armature 9. Further, the sound absorbing material 22 is bonded to the inner surface of the rear cover 15 and extends to the vicinity of the rear surface of the substrate 5, and is provided with a hole through which the guide pole 19 passes.

Next, the print head 1 constructed as described above
The operation will be explained. Similar to a conventional spring-charged print head, when a current is applied to the corresponding coil 4 based on a print command, the armature 9 starts operating and the wire 12 collides with the print medium (not shown). Printing is performed. Further, when the current application to the coil 4 is finished, the armature 9 is magnetically attracted to the core portion 3 of the yoke 2 and returns to the initial position. In this return operation, the rear surface of the block 10 collides with the front surface of the core portion 3. This collision gives high-frequency vibration to the yoke 2, and is radiated directly into the space within the print head 1 as a collision sound. Although this sound wave is largely absorbed and attenuated by the sound absorbing materials 21 and 22, a portion of its energy generates surface waves on the inner surfaces of the head frame 14 and the rear cover 15. The surface waves cause the entire head frame 14 and rear cover 15 to vibrate. However, since the head frame 14 and rear cover 15 are made of a zinc-based alloy that has excellent vibration damping properties,
The vibrations mentioned above are significantly damped. This vibration further vibrates the air outside the print head and becomes a sound wave again which is radiated to the outside world of the print head, but compared to the sound wave generated when the armature 9 and the core part 3 first collide, the sound wave is As described above, a large amount of energy is dissipated by the sound absorption effect inside the print head and the vibration damping effect by the head frame 14 and the rear cover 15, so that the amount of energy is much smaller.

Therefore, in the print head 1 according to the present invention, the collision sound generated when the armature 9 collides with the core portion 3 is attenuated by the sound absorbing materials 21, 22, the head frame 14, and the rear cover 15, and the sound is attenuated by the print head. 1 I have to go outside.

[0015]

As explained above, the wire dot type print head according to the present invention has the front and rear print head covers formed of a material with high vibration damping properties into a substantially bowl shape, and with their opening sides facing each other. Moreover, since a sound-absorbing material is arranged inside this print head cover, the impact sound generated when the armature collides with the core is attenuated by the sound-absorbing material, and furthermore, when it vibrates in the front and rear print head covers and is transmitted, the vibration is suppressed. is significantly attenuated. Therefore, the noise generated by the print head can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a wire dot print head according to the present invention.

[Explanation of symbols]

2 York 3 Core part 9 Armature 12 Wire 14 Head frame 15 Rear cover 21 Sound absorbing material 22 Sound absorbing material

Claims (1)

[Claims] 1. A wire dot type print head comprising an armature having a printing wire, a core to which this armature is attracted, and front and rear print head covers that sandwich and hold these members. A wire dot type print head characterized in that the print head is formed into a substantially bowl shape using a material with high vibration damping properties, the opening sides thereof are opposed to each other, and a sound absorbing material is disposed inside the print head cover.