JPH061040A - Impact dot printer - Google Patents

Abstract

PURPOSE:To reduce the noise of an impact dot printer and increase the attenuation of a sound wave of 1kHz or more by partially changing the cross-sectional area of the printing paper discharge route between a paper guide member and a cover. CONSTITUTION:Sound suppressing members 1a are provided over two or more stages in close vicinity to the upper surface 17c of the paper discharge plate 17 positioned above a print head 8 and a platen 6 and the sound wave advancing along the upper surface 17c of the paper discharge plate 17 can be effectively suppressed. That is, when there is a part changed in cross-sectional area in the a sound wave transmission route, the particle speed of a medium becomes discontinuous across the part and the reflection of a sound wave is generated. Since the reflection of a sound wave becomes large as cross-sectional area change quantity becomes larger and the protruding quantity of the sound suppressing member 1a to the printing paper discharge route is larger than that of a sound suppressing member 2a and the cross-sectional change quantity of the member 1a is larger than that of the member 2a, large sound suppressing effect is obtained. Since the reflection of a sound wave is repeated by a plurality of the sound suppressing members 1a, 2a, the energy of a sound wave is attenuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact dot printer.

[0002]

2. Description of the Related Art Conventionally, an impact dot printer drives a print wire built in a print head to apply an impact force to a print sheet via an ink ribbon to perform printing, and noise is generated when the print wire collides. However, this noise leaks to the outside of the impact dot printer from the ejecting portion of the printing paper, increasing the noise level of the impact dot printer. As a noise countermeasure of this impact dot printer,
The one disclosed in Japanese Utility Model Laid-Open No. 64-48263 is known. The configuration will be described with reference to FIGS. 6 and 7. Figure 6
FIG. 7 is a perspective view of the printer cover of the impact dot printer as seen obliquely from above, and FIG.
It is sectional drawing cut | disconnected by and seen from the arrow D direction. The printing paper discharge unit is covered by the second printer cover 501 and the first printer cover 502 to form a printing paper discharge path. The second printer cover 501 is arranged so as to face the sheet guide 503, and the second printer cover 501 is provided with a plate-shaped muffling member 504 and a paper guiding member 505 that project into the printing paper discharge path. This muffling member 50
According to No. 4, the cross-sectional area of the printing paper discharge path is partially changed, and the sound wave transmitted through the printing paper discharge path is reflected at that portion to reduce the noise level.

[0003]

However, in such a structure, the printing paper 51 is placed along the upper surface of the sheet guide 503.
When 0 is discharged, if the print paper has a weak stiffness, it floats from the sheet guide 503 and comes into contact with the noise reduction member 504 or the paper guide member 505. When the printing paper with weak stiffness comes into contact, the guiding of the printing paper 510 by the paper guiding member 505 becomes insufficient, the printing paper 510 stays at the contact portion, and the printing paper 510 is not discharged. Therefore, it is necessary to provide a certain amount of space above the sheet guide 503 so that the printing paper 510 does not come into contact with the silencing member 504 or the paper guiding member 505. Due to this space, the sound deadening effect of the sound deadening member 504 is lowered, and there is a problem that a desired noise level cannot be obtained. Further, a print head and a platen are arranged below the second printer cover 502, and when the print paper 510 is discharged, the end surface of the print paper 510 is discharged toward the second printer cover 502. Therefore, if a muffling member is provided below the second printer cover 502, the printing paper 510 is likely to come into contact with the muffling member and become caught in the muffling member, resulting in a decrease in sheet ejection performance. For this reason, there is also a problem that a noise reduction member cannot be provided under the second printer cover and noise cannot be reduced in the vicinity of a sound source such as a print head or a platen, so that effective noise reduction cannot be achieved.

The present invention has been made to solve the above problems, and an object thereof is to provide a low noise impact dot printer.

[0005]

SUMMARY OF THE INVENTION The present invention provides an impact dot printer having a print head and a platen with a cover for covering a printing paper discharge section, and a printing paper discharge path between the cover and the printing paper discharge section. In the impact dot printer in which the cross-sectional area of the printing paper discharge path is partially changed in the middle of the printing paper discharge path, a plate-shaped paper guide member that guides and supports the printing paper above the print head or platen is provided. It is characterized in that the cross-sectional area of the printing paper discharge path is partially changed between the paper guide member and the cover.

[0006]

1 is a perspective view of an impact dot printer 100 showing an embodiment of the present invention. FIG. 2 is a cross-sectional view of the impact dot printer 100 in FIG. 1 taken along the line AA and seen from the direction of arrow B. An embodiment of the present invention will be described with reference to FIGS.

The impact dot printer 100 forms an exterior by a case 3, and the upper surface of the case 3 is covered with a first printer cover 1 and a second printer cover 2. One end of the first printer cover 1 is an end 3a of the case 3.
Rotatably engages with the other end of the first printer cover 1,
It is rotatably engaged with the second printer cover 2. Below the first printer cover 1 and the second printer cover 2,
A discharge unit for the printing paper 4 is formed. The printing paper 4 is fed by a paper feed port 14 provided between the case 3 and the sheet guide 12.
The paper is fed from the tractor 5 and fed by the tractor 5. The printing paper conveyed by the tractor 5 is a paper guiding member provided above the platen 6 after being wound around the platen 6.
The paper is ejected by the paper ejection plate 17 and the paper feed roller 18, is conveyed along the upper surface of the sheet guide 12, and the paper ejection port 1 is provided between the second printer cover 2 and the sheet guide 12.
5 is ejected to the outside of the impact dot printer 100. The print head 8 is arranged to face the platen 6,
The print head 8 contains a plurality of print wires.
The print head 8 is mounted on the carriage 9, and the carriage 9
Can be moved by being guided by the first guide shaft 10 and the second guide shaft 11. When the carriage 9 moves, the print wire built in the print head 8 is driven at an appropriate timing to form dots on the print paper 14 via the ink ribbon 16 to perform printing. A printing paper discharge path is formed below the first printer cover 1 and the second printer cover 2. A plurality of plate-shaped muffling members 1 a, 2 a projecting from the first printer cover 1 and the second printer cover 2 are provided in the printing paper discharge path. The muffling member 1 a provided on the first printer cover 1 is provided on the upper surface 17 c of the paper ejection plate 17 along the upper surface 17 c of the paper ejection plate 17.
It is placed as close as possible to. The reinforcing member 1d is provided so as to connect between the sound deadening members 1a,
Is also arranged along the upper surface 17c of the paper discharge plate 17 and close to the upper surface 17c of the paper discharge plate 17. This reinforcing member 1d
Is provided to increase the strength of the first printer cover 1, and if used for a long period of time, a large component such as the first printer cover 1 will undergo creep deformation and come into contact with other components to cause a malfunction. There was a problem such as
In this embodiment, since the reinforcing member 1d is provided, that problem does not occur. As shown in FIG. 3, the paper discharge plate 17 has a paper holding guide portion 17a so that the printing paper 4 sent from the platen 6 can be held and guided, and the leading end of the printing paper 4 sent from the platen 6 is , Paper holding guide 1
After being caught by 7a, it is guided to the paper feed roller 18 along the paper guide portion 17b. The print paper 4 is delivered to the sheet guide 12 by the paper feed roller 18 by receiving the paper discharge force. Therefore, the printing paper 4 is guided and discharged by the paper discharge plate 17 and the paper feed roller 18, so that it does not interfere with the sound deadening member 1a, and the sound deadening member 1a is discharged.
The upper surface 17c of 7 can be arranged in close proximity. FIG. 4 is a bottom view of the first printer cover 1 and the second printer cover 2 as viewed from below. The plurality of reinforcing members 1d and the paper guiding member 2 are shown.
d are arranged with an appropriate interval. The inclined portion 1b of the first printer cover 1 is made of a transparent member, and is on the left side of the print head 8 and the platen 6 (in FIG. 2).
Is provided at a position, and a certain space is provided between the inclined portion 1b and the noise reduction member 1a. As a result, the visibility of the print result immediately after being printed by the print head 8 is improved. A paper cutter 1c is provided near the engaging portion of the first printer cover 1 with the second printer cover 2, and when the printing paper 4 is cut, the second printer cover 2 is engaged with the first printer cover 1. Part to rotate in the direction of arrow E until the upper surface of the second printer cover 2 contacts the upper surface of the first printer cover 1. Next, the printing paper 4 is brought into contact with the paper cutter 1C, and the printing paper 4 is pulled upward, whereby the printing paper 4 is cut at the contact portion with the paper cutter 1C. Further, a sound absorbing material 7 is provided above the print head of the first printer cover 1,
It has a sound absorbing effect.

When the printing paper 4 is conveyed over the upper surface of the sheet guide 12, the noise canceling member 2a provided on the second printer cover 2 is separated from the platen 6 which sends out the printing paper 4, so that the printing is performed. Since the paper 4 is easily deformed and may float from the upper surface of the sheet guide 12,
The protrusions are provided in the printing paper discharge path at appropriate intervals. Therefore, the spacing between the printing paper 4 and the noise reduction member 1a
Is set to be larger than the distance between the print sheet 4 and the printing paper 4.
A sheet guide 12 located below the second printer cover 2
Has a higher surface that supports the printing paper 4 as it approaches the paper exit 15. This is because the printing paper 4 is the paper exit 15
Since the end 4a of the printing paper 4 floats up when it is ejected from the printer, it is for making it easier to grasp the end 4a of the printing paper 4 by hand. The operability when doing is improved. The protrusion amount of the muffling member 2a provided on the second printer cover 2 into the print sheet discharge path is reduced along the support surface of the print sheet 4 of the sheet guide 12 toward the discharge port 15 side. The spacing between the support surface of the printing paper 4 of the sheet guide 12 and the silencing member 2a is substantially uniform. As a result, the printing paper 4 does not come into contact with the noise reduction member 2a and get stuck and stay there.

The noise generated from the impact dot printer 100 is generated when the print wire built in the print head 8 collides with the platen 6 through the ink ribbon 16 and the print paper and when the print wire is generated inside the print head 8. Noise generated when the driving member collides in the print head 8 is mainly. Therefore, the impact dot printer 100
Most of the noise is generated from the position where the print head 8 and the platen 6 are located. Therefore, in order to reduce noise, it is effective to mute the sound near the print head 8 and the platen 6 and attenuate the sound waves emitted from the openings of the impact dot printer 100. In the present embodiment, part of the noise generated from the print head 8 and the platen 6 is generated by the sound absorbing material 7 provided on the lower surface of the first printer cover 1.
The energy is absorbed by, and most of the rest passes through the printing paper discharge path formed between the first printer cover 1 and the upper surface 17c of the paper discharge plate 17, the second printer cover 2 and the sheet guide 12, It is emitted from the paper ejection port 15 to the outside of the impact dot printer 100. In the present embodiment, the sound deadening member 1 is located close to the upper surface 17c of the paper discharge plate 17 located above the sound sources of the print head 8 and the platen 6.
Since a plurality of a are provided, the sound wave traveling along the upper surface 17c of the paper discharge plate 17 can be effectively silenced. That is, if there is a portion of the sound wave whose cross-sectional area changes in its transmission path, the particle velocity of the medium becomes discontinuous at that portion and the sound wave is reflected. The larger the cross-sectional area change amount, the greater the reflection of the sound waves. The sound deadening member 1a has a larger projection amount into the printing paper discharge path than the sound deadening member 2a, and thus the cross-sectional area change amount is large. A muffling effect is obtained. By repeating the reflection of the sound waves by the plurality of sound deadening members 1a, 2a provided on the first printer cover 1 and the second printer cover 2, the energy of the sound waves is attenuated, and the impact dot printer is discharged from the paper discharge port 15. 10
The sound wave energy emitted to the outside of 0 becomes less,
The noise level of the impact dot printer 100 can be reduced.

FIG. 5 shows the noise spectrum when the silencing members 1a and 2a are provided on the first printer cover 1 and the second printer cover 2 of this embodiment and when they are not provided. Noise generated from the print head 8 and the platen 6 is 1K
In the present embodiment, it is 1 KHz, since the frequency band above 8 Hz is the main one.
A large sound wave attenuation is obtained at the above frequencies. Further, since the sound that is offensive to the ear is a sound wave of 1 KHz or more, it is possible to obtain a larger effect than the actual attenuation of the noise level in terms of hearing.

[0011]

As described above, according to the present invention, the print head of an impact dot printer, or
Since the plate-shaped paper guide member for guiding and supporting the print paper is provided above the platen to partially change the cross-sectional area of the print paper discharge path, a low noise impact dot printer can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of an impact dot printer showing an embodiment of the present invention.

FIG. 2 is a sectional view of an impact dot printer showing an embodiment of the present invention.

FIG. 3 is an enlarged view of a paper discharge plate and a paper feed roller portion showing an embodiment of the present invention.

FIG. 4 is a bottom view of the printer cover according to the embodiment of the present invention.

FIG. 5 is a noise spectrum diagram showing an impact dot printer showing an example of the present invention and a comparative example.

FIG. 6 is a perspective view of a conventional printer cover.

FIG. 7 is a cross-sectional view of a conventional printer cover.

[Explanation of symbols]

 1 First Printer Cover 2 Second Printer Cover 3 Case 4 Printing Paper 5 Tractor 6 Platen 7 Sound Absorbing Material 8 Print Head 9 Carriage 10 First Guide Shaft 11 Second Guide Shaft 12 Sheet Guide 13 Ribbon Cassette 14 Paper Feed Port 15 Paper Ejection Mouth 16 Ink ribbon 17 Paper ejection plate 18 Paper feed roller

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuhiko Nishizawa 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Co., Ltd. (72) Inventor Motoyuki Shinmura 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Co., Ltd. (72) Inventor Hiroshi Shirotori 3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation

Claims (1)

[Claims] 1. An impact dot printer having a print head and a platen is provided with a cover for covering a printing paper discharge section, and a printing paper discharge path is formed between the cover and the printing paper discharge section. In an impact dot printer in which the cross-sectional area of the discharge path is partially changed in the middle of the print paper discharge path, a plate-shaped paper guide member for guiding and supporting the print paper is provided above the print head or the platen, An impact dot printer, wherein the cross-sectional area of the printing paper discharge path is partially changed between the paper guide member and the cover.