JPH05193207A - Impact printer - Google Patents

Abstract

PURPOSE:To reduce a noise in printing and enhance a printing quality at a low cost by a method wherein a platen in an impact printer is divided into a plurality of parts. CONSTITUTION:In an impact printer which conducts printing by impacting a printing head 1 on printing paper 7 fed onto a platen 6 clamped by a pair of chassis 4 at both ends thereof, the platen 6 having an impact surface on one side is divided into parts by a flat or curved surface disposed at an angle unvertical to the impacting direction, and the divided surfaces with a vibration damping material 13 between are bonded with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact printer which comprises a pair of chassis having platens whose both ends are sandwiched, and which prints by printing a printing paper with a printing element such as a dot printing wire or a printing type.

[0002]

2. Description of the Related Art In a conventional impact printer, a platen printed by a printing element through an ink ribbon and a printing paper is a round platen rotary type made of a rubber type material, and a metal or hard synthetic resin type material. It is roughly divided into two types: flat surface fixed type.

The platen made of a rubber material absorbs an impact generated when it is stamped by a printing element better than a platen made of a metal or hard synthetic resin material. Is small, which is advantageous for noise prevention. However, since the platen made of the rubber-based material has low hardness, when the printing element is printed on the printing paper fed onto the platen via the ink ribbon, the elasticity of the platen surface causes the printing element's elasticity. The character may not be accurately reproduced on the printing paper, which may lead to deterioration of the printing quality. On the other hand, the platen made of a metal or a hard synthetic resin material does not have such a problem, and therefore,
Regarding the printing quality, the platen made of the metal or the hard synthetic resin material is more advantageous.

Further, in the flat surface fixed type platen, as compared with the round platen rotary type platen, since the printing elements are concentrated in the same place, the durability of the rubber type material is difficult and the Alternatively, it is necessary to use a hard synthetic resin material. Therefore, when a flat surface fixed type platen made of metal or a hard synthetic resin material is used, the impact sound generated when printing is performed by the printing element is large, and noise during printing becomes a problem, As a countermeasure, it was necessary to install a soundproof cover and a soundproof design at the place where the printer was used, which led to an increase in costs.

In order to reduce the noise during printing, for example, as described in Japanese Utility Model Laid-Open No. 57-121548, a metal platen having a substantially rectangular cross section and a printing surface on one side is printed. By dividing the divided surface parallel to the surface and joining the divided surface with a vibration damping material interposed,
It has been considered to try to soften the impact force generated when a printing element is used for printing.

[0006]

However, in the structure in which the vibration damping material is interposed on the divided surface parallel to the stamping surface of the platen, the vibration damping material is generated by the impact force generated when the stamping is performed. Just by compressing, the vibration due to impact is not reduced and is transmitted to the chassis as it is, and it is not possible to sufficiently reduce the noise during printing. The present invention solves the above-mentioned problems, and an object of the present invention is to provide an impact printer that achieves low noise at the time of printing at low cost and that is excellent in printing quality.

[0007]

In order to achieve the above object, the present invention prints by printing a printing paper fed on a platen having both ends sandwiched by a pair of chassis with a printing element. In the impact printer that does
A platen having a printing surface on one side is divided by a flat surface or a curved surface having an angle that is not perpendicular to the printing direction, and the divided surface is joined with a vibration damping material interposed.

[0008]

According to the above construction, the platen is divided by a flat surface or a curved surface having an angle that is not perpendicular to the printing direction, and the vibration damping material is interposed on this divided surface.
The vibration damping material is sheared and deformed by the impact force generated when the stamping surface is stamped, and the vibration energy is absorbed. Generally, the elastic material is more damped to the vibration in the shearing direction than to the vibration in the thickness direction, so that the vibration of the platen is immediately converged and the noise caused by this vibration is reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, both ends of the first guide bar 2 and the second guide bar 3 to which the wire dot type print head 1 is mounted are fixed to a pair of chassis 4 and 5 of the printer. Further, both ends of the platen 6 are sandwiched between the chassis 4 and 5 through the fitting of a protrusion formed on the end face of the platen 6 with a positioning hole provided in the chassis and a screw.

FIG. 2 is an exploded detailed view of an attachment portion between one end of the platen and the chassis, and FIG. 3 shows a sectional structure of the platen. As shown in these figures, the platen 6
Is a so-called flat surface fixed type in which the surface to be printed by the printing element is flat, and is formed of an iron material.
And a support portion 12. The divided end surfaces are two flat surfaces (surfaces that are V-shaped in side view) extending obliquely upward and downward from the center side in the printing direction, and a vibration damping material 13 such as a viscoelastic resin is interposed on the divided surfaces. Each is bonded with an adhesive or the like. In the present embodiment, the angle between these two planes is approximately 45 degrees and approximately 135 degrees with respect to the horizontal plane, but this value needs to be designed by appropriately changing it depending on the resistance of the adhesive surface to shearing and the like. There is. Also, the thickness of the vibration damping material needs to be appropriately changed according to its resistance and the like.

The entire length of the support portion 12 in the longitudinal direction is the same as the distance between the pair of chassis 4 and 5, and the end face thereof has a cylindrical projection 15 and a screw hole 25. Has a length slightly shorter than that of the support portion 12, and has a cylindrical projection 14 on its end face. Further, the chassis 4 has an elongated hole 21, a positioning hole 22 and a screw hole 23.

By fitting the projection 15 of the support portion 12 of the platen 6 with the positioning hole 22 and the projection 14 of the stamping portion 11 with the elongated hole 21, respectively, the platen 6 is sandwiched by the chassis 4 and supported. The portion 12 is fixed by a platen mounting screw 24 through a screw hole 23 of the chassis 4. The diameter of the protrusion 15 and the diameter of the positioning hole 22 are the same, which allows the platen 6 to be accurately positioned. The long width of the long hole 21 is the same as the diameter of the projection 14, while the long width thereof is larger than the diameter of the projection 14, so that the printing portion 11 of the platen 6 is formed during printing. It can move in the direction P of the impact force (the same as the above-mentioned printing direction). Further, since the stamped portion 11 has a shorter overall length in the longitudinal direction than the support portion 12, the vibration of the stamped portion 11 is directly transmitted to the chassis 4 and 5 by providing a gap in the mounting portion with the chassis 4 and 5. There is no.

In the above structure, when the print head 1 is driven based on the print data inputted from the outside and the platen 6 is printed through the ink ribbon 8 and the print paper 7, as shown in FIG. Force is applied in the direction. Platen 6
When the divided end surfaces of the stamping portion 11 and the supporting portion 12 are formed into a surface other than a plane perpendicular to the stamping direction, the vibration damping material 13 interposed between the stamping portion 11 and the supporting portion 12 is Shear easily due to impact force in the P and P directions. Therefore, the vibration damping material 1
When 3 is formed so that its end surface has a V-shape, the impact force in the P direction is decomposed by the vibration damping material 13 in the X1 and X2 directions, and the vibration damping material 13 is sheared and deformed. The vibration energy at the time of stamping is consumed and the supporting portion 12
The vibrational energy transmitted to the chassis 4 and 5 is reduced, and the vibrational energy transmitted to the chassis 4 and 5 is reduced. As a result, noise caused by vibration during printing can be reduced.

In comparison with the construction disclosed in Japanese Utility Model Laid-Open No. 57-121548, if the thickness of the vibration damping material is the same,
It has been confirmed by experiments that a much higher vibration damping rate can be achieved and a higher soundproofing effect can be obtained. Further, as another embodiment, as shown in FIG. 4, a vibration damping material may be interposed except for the central tip of the V-shaped divided end face of the platen. Further, the divided end surface may be formed in an inverted V shape, an oblique shape, or a curved surface (arc surface) as long as it is a surface other than a plane perpendicular to the printing direction. In particular, if the dividing surface is formed in a symmetrical shape with respect to the printing direction, the strength of the platen can be increased.

[0015]

As described above, according to the present invention, in an impact printer, a platen having a printing surface on one side is divided by a flat surface or a curved surface having an angle not perpendicular to the printing direction, and Since the divided surfaces are joined with the vibration damping material interposed, the vibration damping material is sheared and deformed by the impact force generated when it is stamped, and the vibration energy is absorbed. As a result, the vibration of the platen is immediately converged, and the noise caused by this vibration can be reduced. Further, since the vibration of the platen itself is reduced, the gap between the print head and the print paper does not change during printing, print unevenness is eliminated, and high print quality can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a main part of an impact printer according to an embodiment of the present invention.

FIG. 2 is a partially enlarged perspective view showing a disassembled mounting portion of one end portion of the platen and the chassis according to the present embodiment.

FIG. 3 is a side sectional view of the platen according to the present embodiment.

FIG. 4 is a side sectional view of a platen according to another embodiment.

[Explanation of symbols]

 1 print head 4 chassis 5 chassis 6 platen 7 printing paper 11 stamping part 12 support part 13 vibration damping material

Claims (1)

[Claims] 1. An impact printer for printing by printing printing paper fed on a platen whose both ends are sandwiched between a pair of chassis with a printing element, wherein the platen has a printing surface on one side. The impact printer is characterized in that the sheet is divided by a flat surface or a curved surface having an angle that is not perpendicular to the printing direction, and the divided surface is joined with a vibration damping material interposed.