JP2000318191A - Dot impact printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a good heat dissipation effect by providing a heat sink having a columnar protrusion fitted tightly to the inner circumferential wall surface of a yoke having a tubular wall on the inside of a core and a part for coupling the core thermally and magnetically. SOLUTION: A part 4 for coupling the tubular wall 2 of a yoke 1 thermally and magnetically with a core 5 fitted with a coil 6 is formed integrally with the yoke 1 and an armature 9 is supported retractably by a fulcrum 10 through a film 8 at a part on the end face 7 of the wall 2 of the side opposite to the bottom face 3 of the yoke 1. An armature guide 13 for supporting the reset spring 14 of the armature 9 abuts against the outer side face of a supporting plate 12. The yoke 1 is fitted, at one end thereof, to the supporting plate 12 and contained in a housing 20 provided with a substrate 21 connected with the coil 6 on the outside of the bottom face. A heat sink 23 having a columnar protrusion 24 is fitted tightly to the inner circumferential surface of the wall 2 and an armature stopper 27 is provided on the end face of the protrusion 24 in order to determine the reset position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art First, the configuration of a conventional dot impact printer head will be described with reference to FIG. In this example, the dot impact printer head B is formed by assembling a front block 100 and a rear block 101. Front block 100
Is an armature guide 103 surrounded by a front housing 102, and the armature guide 103
Plate 1 having a plurality of armatures 104 radially supported on the armature and an annular armature stopper 105 for determining a return position of these armatures 104
06 and a nose 107.

The nose 107 is an armature guide 103
The nose 107 has a plurality of wires 1 brazed to the ends of the individual armatures 104.
Tip guide 109 that aligns and supports slidable 08
And a plurality of intermediate guides 110 that slidably support an intermediate portion of the wire 108. The stopper plate 106 is attached to the armature guide 103 by screws (not shown). Further, the armature guide 103 is integrally formed with a plurality of columns 111 for guiding the undulating operation of the individual armatures 104, and the armature 104 is connected to the armature stopper 10
A plurality of return springs 112 biasing the armature 104 toward the fulcrum 5 and a fulcrum pressing spring 113 for pressing the armature 104 to the fulcrum portion 114 with an urging force smaller than the urging force of these return springs 112 are provided.

[0004] The rear block 101 includes an armature 10.
And a plurality of cores 116 integrally formed on the outer periphery of the yoke 115 and facing the armature 104.
And a coil 117 fitted to these cores 116,
It includes a substrate 118 to which these coils 117 are connected, and a cup-shaped heat sink 119 which also serves as a housing surrounding the yoke 115 and the substrate 118. The heat sink 119 penetrates through the center of the substrate 118 and the yoke 115
The boss 120 is in contact with the bottom surface of the yoke 115, and the boss 120 is coupled to the yoke 115 by a screw 121.

[0005] The front block 100 and the rear block 101 are connected with a plurality of screws (not shown) penetrating the front housing 102 and the armature guide 103.
Is screwed around the yoke 115.

[0006] Such a dot impact printer head B is mounted on a carrier (not shown) that moves along a platen. When a current is supplied to the selected coil 117 in the process of moving the carrier, the armature 1
The wire 108 is attracted to the core 116, so that the wire 108 collides with the platen via the ink ribbon (not shown) and the paper. That is, printing is performed. Since the energization of the coil 117 is instantaneous, the armature 104
8 is returned by the reaction force received from the platen and the urging force of the return spring 112, and comes into contact with the armature stopper 105 to determine the return position. The heat generated by the coil 117 is transmitted to the heat sink 119 via the yoke 115 and is radiated to the outside.

[0007]

In a dot impact printer head, since the coil generates heat, it is desirable to radiate heat by directly contacting a heat sink with a metal member such as a yoke. In this case, the heat generation temperature is highest near the coil, but there is no configuration in the conventional dot impact printer head in which a heat sink is brought into contact with a portion of the yoke near the coil. For example, in the example shown in FIG.
The boss 120 is merely in contact, and since this portion is separated from the coil 117, heat transfer is slow, heat is easily trapped inside, and a good heat radiation effect cannot be expected.

The present invention has been made in view of the above points, and has as its object to provide a dot impact printer head capable of obtaining a good heat radiation effect.

[0009]

According to the first aspect of the present invention,
A plurality of cores each having a coil mounted thereon and arranged in an annular shape, a plurality of armatures that are driven by magnetic force generated in the core when the coil is energized to move a wire in a printing direction, and the armature is a printing direction. Return means for returning in the opposite direction, an armature stopper for determining a return position of the armature to be returned by the return means, a connecting part to which the core is thermally and magnetically connected, and a cylinder disposed inside the core A yoke having a cylindrical wall, and a heat sink having a columnar protrusion fitted in contact with the inner peripheral surface of the cylindrical wall of the yoke.

Therefore, the heat generated in the coil can be transmitted to the cylindrical wall of the yoke closest to the coil, and further transmitted from the inner peripheral surface of the cylindrical wall to the heat sink.

According to a second aspect of the present invention, in the first aspect, the heat sink includes an annular flat surface that is in contact with a bottom surface of the yoke in addition to the columnar protrusion.

Therefore, the contact area between the yoke and the heat sink is further increased, so that the heat radiation effect is promoted.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. FIG. 1 is a vertical sectional side view of a dot impact printer head A. 1 is a yoke. The yoke 1 is formed with a cylindrical wall 2 whose both end faces are open, and an annular connecting portion 4 extending from the bottom surface 3 to the outside of the cylindrical wall 2. The connecting portion 4 thermally and magnetically connects the plurality of cores 5 to the yoke 1, and in the present embodiment, the core 5 is formed integrally with the connecting portion 4 of the yoke 1. . Of course, the core 5 may be formed of a separate member and fixed to the connection portion 4. A coil 6 is fitted to the core 5. A part of the end surface 7 of the cylindrical wall 2 opposite to the bottom surface 3 of the yoke 1 is a fulcrum 10 that supports the armature 9 via a film 8 so as to be able to move up and down.

Further, the end surface 7 of the cylindrical wall 2 of the yoke 1
A plurality of studs 11 are provided upright through an intermediate portion between the film 8 and the armature 9, and a support plate 12 is in contact with end surfaces of the studs 11. An armature guide 13 is in contact with the outer surface of the support plate 12, and an armature spring 14 is supported on the armature guide 13 as return means for returning the armature 9.

The flange 16 of the nose 15 is in contact with the outer surface of the armature guide 13. The nose 15 is provided with a tip guide 18 that slidably supports a tip of a wire 17 brazed to an end of the armature 9 and an intermediate guide 19 that slidably supports an intermediate portion of the wire 17. Have been. The yoke 1, the support plate 12, the armature guide 13, and the flange 16 of the nose 15 are assembled with screws (not shown).

The above-described yoke 1 is housed in a housing 20 in which a support plate 12 is fitted at one end. On the outside of the bottom surface of the housing 20, a substrate 2 to which the coil 6 is connected is provided.
1 and an insulating film 22 are provided. Reference numeral 23 denotes a heat sink, and a columnar projection 24 fitted in contact with the inner peripheral surface of the cylindrical wall 2 of the yoke 1 in the heat sink 23.
And a flat surface 25 that is in contact with the bottom surface 3 of the yoke 1. The yoke 1 and the heat sink 23 are joined by screwing a screw 26 passing through the flat surface 25 to the cylindrical wall 2.

A stopper plate 28 having an armature stopper 27 for determining the return position of the armature 9 is provided on the end surface of the columnar projection 24 of the heat sink 23.
Is provided via The stopper plate 28 is fixed to the columnar projection 24 by a screw 30. In this case, the contact area between the cylindrical wall 2 of the yoke 1 and the columnar projection 24 is larger than the contact area between the columnar projection 24 of the heat sink 23 and the sheet 29.

In this embodiment, the number of cores 5 and armatures 9 is nine. The yoke 1
Although the cross-sectional shape of the cylindrical wall 2 and the columnar protrusion 24 of the heat sink 23 is formed in a 9-octagonal shape, a circular shape does not pose any problem.

In such a configuration, when the coil 6 is energized, a magnetic flux flows through the core 5, the armature 9, and the yoke 1, so that the armature 9 is supported by the fulcrum 10 against the urging force of the armature spring 14. The wire 17 is sucked by the core 5 and the wire 17 is
2 collides with the platen 33. Thereby, printing is performed.

The period during which the coil 6 is energized is instantaneous, and the armature 9 is restored by the reaction force of the wire 17 from the platen 33 and the urging force of the armature spring 14. At the time of this return, the armature 9 comes into contact with the armature stopper 27 and the return position is determined.

The heat generated from the coil 6 is transmitted to the cylindrical wall 2 of the yoke 1 near the coil 6, and the columnar projection 24 of the heat sink 23 is in contact with the inner peripheral surface of the cylindrical wall 2. Since the flat surface 25 of the heat sink 23 is in contact with the bottom surface 3 of the yoke 1, the heat of the coil 6 is quickly transmitted to the heat sink 23 and is radiated from the heat sink 23.

[0022]

According to the first aspect of the present invention, the heat generated in the coil is reduced by fitting the columnar projection of the heat sink into contact with the inner peripheral surface of the cylindrical wall formed on the yoke. The heat can be transmitted to the cylindrical wall of the yoke closest to the coil, and further transmitted to the heat sink from the inner peripheral surface of the cylindrical wall, whereby a good heat radiation effect can be obtained.

According to the second aspect of the present invention, since the heat sink has an annular flat surface in contact with the bottom surface of the yoke in addition to the columnar protrusion, the contact area between the yoke and the heat sink is further increased, and the heat radiation effect is improved. Can be promoted.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a dot impact printer head according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing an example of a conventional dot impact printer head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Yoke 2 Cylindrical wall 3 Bottom surface 4 Connection part 5 Core 6 Coil 9 Armature 14 Returning means 17 Wire 23 Heat sink 24 Columnar projection 25 Flat surface 27 Armature stopper

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masayuki Iinuma 6-78, Minamimachi, Mishima-shi, Shizuoka Toshiba Tec Corporation Inside the Mishima Plant (72) Inventor Yasunobu Terao 6-78, Minami-cho, Mishima-shi, Shizuoka Toshiba Tec (72) Inventor Kazuya Takagi 6-78, Minamimachi, Mishima-shi, Shizuoka Toshiba Tec Corporation F-term (reference) 2C063 AC12 AC13 AF01 AF18 AF27 AF31 AF40

Claims (2)

[Claims] A plurality of cores each having a coil mounted thereon and arranged in an annular shape; a plurality of armatures driven by magnetic force generated in the cores when energizing the coils to move a wire in a printing direction; and the armature. Return means for returning the armature in a direction opposite to the printing direction; an armature stopper for determining a return position of the armature to be returned by the return means; and a connection portion where the core is thermally and magnetically connected and inside the core. A dot impact printer head, comprising: a yoke having a cylindrical wall disposed at a first position; and a heat sink having a columnar protrusion fitted in contact with the inner peripheral surface of the cylindrical wall of the yoke. 2. The dot impact printer head according to claim 1, wherein the heat sink has an annular flat surface in contact with a bottom surface of the yoke, in addition to the columnar protrusion.