JP3097716B2 - Impact dot printer - Google Patents

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, and more particularly, to an impact dot printer characterized by a noise reduction mechanism.

[0002]

2. Description of the Related Art In an impact dot printer,
Many proposals have been made for a mechanism for suppressing noise generated during printing, and the mechanism disclosed in Japanese Utility Model Laid-Open Publication No. 64-48263 discloses a mechanism in which an inner surface of a printer cover that covers an upper surface of a printer main body has a direction perpendicular to a paper discharging direction. The noise reduction ribs are projected to prevent the noise generated during printing from leaking to the outside.However, the noise reduction ribs are omitted so as not to come in contact with the discharged paper in the area that covers the printing section. However, the noise reduction effect is reduced by that amount, and in the portion covering the paper discharge path, a certain gap is provided between the noise reduction rib and the paper discharge path so as not to come in contact with the floating paper. There is also a problem that a sufficient noise reduction effect cannot be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem.
An object of the present invention is to provide a new impact dot printer that can smoothly guide printed paper and effectively reduce noise generated inside the printer.

[0004]

That is, according to the present invention, as an impact dot printer for achieving the above object, a printer cover for covering an upper surface of a printer main body is formed by a first material formed of a transparent material for covering above a printing portion. The printer comprises a printer cover and a second printer cover which covers the upper part of a paper discharge guide provided on the lower side of the paper discharge direction. A guide rib extending in the paper discharge direction is provided on the inner surface of the first printer cover. And a muffling rib extending in a direction perpendicular to the paper discharging direction is provided except for a portion facing the printing unit,
On the inner surface of the printer cover, short ribs are provided, each of which extends in a direction perpendicular to the sheet discharging direction.

[0005]

Embodiments of the present invention will be described below. The drawings all show one embodiment of the present invention.

The impact dot printer main body 100
The case 3 is provided with a sheet guide 12 at the other end, and the paper 4 drawn in from a paper feed port 14 provided below is fed between the platen 6 and the print head 8 by the tractor 5 for printing. It is configured to discharge the sheet along the upper surface of the sheet guide 12 to the outside.

In the figure, reference numerals 1 and 2 denote first and second printer covers which cover the upper surface of the case 3. One end of the first printer cover 1 has a case so as to cover the platen 6 and the upper portion of the print head 8. 3 is pivotally supported by the opening end 3a so as to be openable and closable.
The first printer cover 1 is rotatably attached to the other end of the first printer cover 1 so as to cover the upper surface of the first printer cover 1.

The first printer cover 1 is formed of a transparent member. The printer cover 1 has an inclined step portion 1b at a portion where the platen 6 and the print head 8 face each other so that the printing state can be visually recognized. Is formed,
On its inner surface, there are several silencing ribs 1a except for this part.
‥‥ is formed so as to protrude toward the platen 6 in a direction orthogonal to the sheet discharging direction.

On the inner surface of the printer cover 1,
Several paper guide ribs 1d extending in the paper discharging direction are sound absorbing ribs 1.
a, and the lower edges of these paper guide ribs 1d # extend from the vicinity of the peripheral surface of the platen 6
It forms a gentle curve toward the connection point with the printer cover 1, and as shown in FIG. 3, makes slight contact with the leading end of the paper 4 sent out from the platen 6, It is configured such that only the push-back force fa is applied.

That is, when the pressure applied to the paper 4 by the lower edge of the paper guide rib 1d is f, the force fa for pushing back the paper 4 is expressed as fa = fsinθ. Paper 4
Is configured to be as small as possible.

Further, at the other end of the first printer cover 1, a paper cutter 1 c for cutting the paper 4 is provided on the inner surface side, and the second printer cover 2 is connected to the upper surface of the first printer cover 1. The paper 4 is configured to be cut by exposing the paper cutter 1c from the end by inverting the paper back to back.

On the other hand, some muffling ribs 2a # and guide ribs 2d # are also provided on the inner surface of the second printer cover 2.
Are formed so as to protrude in a direction perpendicular to the paper discharge direction and in a paper discharge direction.

The ribs 2a and 2d are formed at a substantially uniform height so as to keep a constant distance from the surface of the sheet guide 12 so that the ribs 2a and 2d do not come into contact with the sheet 4 and are caught. It is formed so as to gradually decrease as it approaches the paper exit 15.

Reference numeral 7 in the figure denotes a sound absorbing material adhered to the inner surface of the first printer cover 1 so as to cover the upper part of the print head 8, and 12a denotes a sound absorbing material of the discharged paper 4. A guide piece protruding from the upper surface of the sheet guide 12 is shown so that the leading end can be lifted from the upper surface of the sheet guide 12 to make it easier to pick.

In the printer constructed as described above, with the first printer cover 1 made of a transparent material closed, a printing section is appropriately formed through a portion of the inclined step portion 1b from which the silencing rib 1a is omitted. Print while monitoring.

When desired printing is performed on the paper 4 sent to the printing unit in this way, the printing wire and the platen 6
Or a collision between the print wire driving members inside the print head 8 generates noise. A part of the noise is absorbed by the sound absorbing material 7 provided on the inner surface of the first printer cover 1. Most of the rest is effectively attenuated in the cavity formed by the silencing ribs 1a, 2a and the guide ribs 1b, 2b while the paper 4 passes between the first and second printer covers 1, 2. Let me do.

That is, if there is a portion in the transmission path of the sound wave whose cross-sectional area changes greatly, the velocity of the particles in the medium becomes discontinuous from that portion, and the sound wave is reflected. Is larger as the change amount of the
Since the noise reduction rib 1a provided on the printer cover 1 has a larger protrusion and a larger variation in the cross-sectional area of the cavity than the noise reduction rib 2a provided on the second printer cover 2, the noise reduction rib 1a passes through the paper discharge path. For the most part, the reflection is repeated by the cavity on the inner surface of the first printer cover 1, and the energy of the sound wave is significantly reduced. Then, the remaining energy is reduced by the cavity provided on the inner surface of the second printer cover 2. It is discharged from the paper discharge port 15.

FIG. 5 shows the respective noise spectra when the silencing ribs 1a and 2a are provided on the first and second printer covers 1 and 2, and when they are not provided.
The noise caused by the collision between the printing wire and the platen 6 and the noise generated inside the printing head 8 are both mainly 1 kHz or more which cause great annoyance. 1 Silencing rib 1 of printer cover 1
It has been clarified that the noise can be effectively attenuated by the noise reduction rib 2a of the second printer cover 2 and the noise reduction rib 2a.

[0019]

As described above, according to the present invention, the inner surface of the printer cover made of a transparent material covering the upper part of the printing portion is provided.
Since the silencing rib in the direction perpendicular to the paper discharging direction is provided except for the portion facing the printing unit, the guide rib extending in the paper discharging direction is provided so as to contact the leading end of the paper at a slight angle, The noise generated during printing can be effectively attenuated by reflecting the noise in the cavity formed by these ribs, and the noise reduction rib is omitted with the printer cover closed. Through the part, you can observe the printing state from the outside as appropriate,
Furthermore, by making the lower edge of the guide ribs a slight angle with the leading edge of the paper, the printed paper can be printed despite the fact that there are many cavities on the inner surface of the printer cover for noise reduction. It can be discharged outside without any trouble.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing the inside of the printer.

FIG. 3 is a sectional view showing a main part of the printer cover.

FIG. 4 is a view of the printer cover as viewed from the inside.

FIG. 5 is a diagram illustrating each noise spectrum when a noise reduction rib is provided and when it is not provided.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st printer cover 1a sound deadening rib 1b paper guide rib 2 2nd printer cover 2a sound deadening rib 2b paper guide rib 6 platen 7 sound absorbing material 14 paper feed port 15 paper discharge port

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Shirotori 3-5-5 Yamato, Suwa-shi, Nagano Inside Seiko Epson Corporation (72) Inventor Motoyuki Shinmura 3-5-3 Yamato, Suwa-shi, Nagano Inside Seiko Epson Corporation (72) Inventor Katsuhiko Nishizawa 3-5-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (56) References Japanese Utility Model 3/88758 (JP, U) Japanese Utility Model Utility 52 153 407 (JP, U) Japanese Utility Model Hei 3-88757 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) B41J 29/08 B41J 29/12

Claims (2)

(57) [Claims] A first cover formed of a transparent material covering an upper portion of a printing section;
The printer comprises a printer cover and a second printer cover which covers the upper part of a paper ejection guide provided on the lower side of the paper ejection direction. A guide rib extending in the paper ejection direction is provided on the inner surface of the first printer cover. A noise reduction rib is provided so as to be in contact with the leading end at a slight angle, and a noise reduction rib extending in a direction orthogonal to the paper discharge direction is provided except for a portion facing the printing unit, while an inner surface of the second printer cover has An impact dot printer, comprising short ribs extending in a direction perpendicular to the sheet discharging direction. 2. The impact dot printer according to claim 1, wherein a sound absorbing material is adhered to an inner surface of a portion of the first printer cover corresponding to the print head.