JP2002019163A - Wire dot print head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wire dot print head in which print quality is made uniform among respective print head units, while enhancing the degree of freedom of layout, by cooling the print head units on each stage uniformly regardless of the supplying direction of cooling air. SOLUTION: The wire dot print head comprises print head units arrange in a plurality of stages wherein a heat dissipating part having heat dissipating fins projected radially from the center is provided at the side wall part on each stage of print head units and the heat dissipating fins are positioned not to overlap on the front view.

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.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 7-96 discloses a wire dot print head having a heat radiating means for generating heat in a printing mechanism.
Nos. 613 and 6-135018 are known. The former is formed by fixing a radiator provided with a plurality of radiating fins on the surface opposite to the nose forming surface, and the latter is formed by fixing the radiator on the side wall of the print head unit. You.

However, in the former case, a plurality of print head units are stacked in the front-rear direction (in this specification, the direction in which the print wires project, ie, the print surface side is the front, and the opposite side is the back). When forming a print head, the radiator can be attached only to the last print head unit, so there is a difference in heat radiation efficiency between the front and rear print head units, and a predetermined print quality is obtained. There is a disadvantage that it cannot be done.

In the latter case, since the radiator is fixed to the side wall of the print head unit, even when a plurality of print head units are stacked and used, the radiator is attached to the front and rear print head units. Can be fixed, but there is a problem that the cooling efficiency in the front and rear print head units changes depending on the blowing direction of the cooling air. That is, in this conventional example, when the cooling air is sent in the stacking direction of the print head unit, for example, the cooling fins other than the last-stage radiating fins are shadowed by the cooling air.
The cooling efficiency of the print head unit on the front stage side is extremely reduced, resulting in a difference in print quality. For this reason, in order to guarantee uniform print quality in all print head units, the installation position of the cooling fan is limited, and the degree of freedom in layout is significantly reduced.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and aims to uniformly cool the print head units in each stage irrespective of the blowing direction of the cooling air. Accordingly, it is an object of the present invention to provide a wire dot print head capable of achieving uniform print quality in each print head unit and further increasing the degree of freedom in layout.

[0006]

A wire dot print head is formed by laminating a plurality of print head units 1 in a direction in which a print wire advances and retreats. Is provided with a heat radiating portion 3 for radiating heat generated in the rear portion of the printing machine. Radiator 3
Has a plurality of radiating fins 2 arranged radially with respect to the center of the print head unit 1, and the radiating fins 2 of the radiating portions 3 at each stage are viewed from the front, that is, viewed from the stacking direction of the print head unit 1. It is arranged so as not to polymerize.

By arranging the radiating fins 2 on the side walls, even if the cooling air is blown from a direction perpendicular to the laminating direction, the cooling air hits the radiating fins 2 of the radiating section 3 of each stage evenly. Even when the direction of the cooling air is coincident with the central axis of the print head, each radiating fin 2 does not become shaded by the radiating fins 2 of the other stages. Are equalized, and an equal cooling effect is obtained in each stage.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 4, a print head is formed by laminating two sets of print head units 1, 1 in upper and lower stages, and a nose 5 is formed in the upper print head unit 1. Fixed.

As shown in FIG. 3, each print head unit 1 has a cover 1a in which a print mechanism section including a plurality of armatures 1b is accommodated.
Is fixed to one end of the printing wire 1c. Each printing wire 1
c is inserted into the guide hole of the wire guide 5a formed in the nose 5 to reach the tip of the nose 5, and when the coil 1d is excited, the armature 1b drives the print wire 1c in the laminating direction of the print head unit 1, and the print wire The other end (printing end) of 1c advances and retracts from the tip of the nose 5. In FIG. 3, reference numeral 1e denotes a magnet base formed of a magnetic material, and 1f denotes a printed circuit board for controlling the exciting operation of the coil 1d.

The cover 1a is formed of a metal material, preferably a material having good thermal conductivity such as aluminum, and the heat radiating portion 3 is fixed to the cover 1a. Radiator 3
Are formed of a material having good heat conductivity such as aluminum, and a plurality of radiating fins 2, 2,... Protrude radially from the outer peripheral wall of the cylindrical portion 3a which fits the outer periphery of the cover 1a. The cylindrical portion 3a extends rearward from the cover 1a and is arranged so as to be in contact with the outer periphery of the magnet base 1e.
A compound material or the like having excellent heat conductivity is interposed between the magnet base 1e and the inner peripheral wall surface of the heat radiating portion 3 to reduce the thermal resistance at the boundary surface. Also, the magnet base 1e and the cover 1a can be bonded with silicon grease having excellent heat conductivity.

As shown in FIGS. 2 and 4, the radiating fins 2 of the radiating portion 3 in the front and rear stages do not overlap when viewed from the front, and when viewed from the front, are positioned in the gaps between the radiating fins 2 in the preceding stage. Are arranged at positions shifted by a half pitch so that the radiating fins 2 face.

Incidentally, in FIG.
Although a case is shown where it is formed separately from and fixed to the cover 1a, it can be formed integrally with the cover 1a in advance, and in this case, manufacturing efficiency can be improved.

A cooling fan 4 is fixed to the rear end of the print head unit 1 at the subsequent stage. The cooling fan 4 is an axial fan that blows cooling air along the central axis of the print head unit 1. Since the cooling fan 4 is fixed to the print head, it is not necessary to arrange a separate cooling unit in the housing. In addition, the size of the entire apparatus can be reduced.

(Supplementary Note 1) A wire dot print head formed by laminating a plurality of stages of print head units, wherein a heat radiating portion in which heat radiating fins protrude radially from the center of a side wall portion of each stage of the print head unit. And a radiating fin of a radiating portion of each stage is arranged at a position where they do not overlap each other when viewed from the front. (Supplementary note 2) The wire dot print head according to supplementary note 1, wherein a cooling fan that blows cooling air forward is fixed to a rear end of the last print head unit. (Supplementary note 3) The wire dot print head according to Supplementary note 1 or 2, wherein the heat radiating unit 3 is formed integrally with a cover of the print head unit.

[0015]

As is apparent from the above description, according to the present invention, the print head units in each stage can be cooled uniformly regardless of the flow direction of the cooling air. Quality can be maintained evenly.

Further, since the arrangement of the cooling fan can be determined only by the arrangement of the peripheral components, the degree of freedom in design is increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a sectional view taken along line 2A-2A in FIG. 2;

FIGS. 4A and 4B are views showing a lower print head unit, and FIG.
FIG. 4B is a sectional view taken along line 4A-4A in FIG. 3, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head unit 2 Heat radiation fin 3 Heat radiation part 4 Cooling fan

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaharu Yoshida 1405 Daimaru Daimaru, Inagi-shi, Tokyo Inside Fujitsu A Isotec Co., Ltd. (72) Inventor Shuichi Yamaki 1405 Daimaru Daimaru Inagi-shi, Tokyo Fujitsu A Isotec Co. 72) Inventor Toshikazu Konishi 1405 Daimaru, Inagi-shi, Tokyo F-term within Fujitsu Isotec Co., Ltd. 2C063 AB18 AC13

Claims (2)

[Claims] 1. A wire dot print head comprising a plurality of print head units stacked on each other, wherein a heat radiating portion provided with heat radiating fins radially from a center is provided on a side wall portion of each of the print head units. And a radiating fin of each radiating section is arranged at a position where they do not overlap each other when viewed from the front. 2. A wire dot print head according to claim 1, wherein a cooling fan for blowing cooling air forward is fixed to a rear end of said last print head unit.