JPH02266955A - Dot printer head - Google Patents

Abstract

PURPOSE:To enable an operator to be protected from a possibility of a burn by a method wherein a synthetic resin protective cover formed in a unitary body by a nose part projected to a platen side and an annular wall surrounding an outer periphery of a yoke is established. CONSTITUTION:A synthetic resin protective cover 10 formed in a unitary body by an annular wall 8 surrounding an outer periphery part of a yoke 2 and a nose part 9 projected to a platen side is provided. An armature 5 is generally seceded from a core 4 and when a specific electromagnetic coil 3 is excited, the armature 5 is attracted to the core 4, pivots centering a fulcrum part 15, and a needle 16 is made to collide against the platen. Though heat is generated by this exciting operation of the electromagnetic coil 3, said heat is transmitted to the core 4, the yoke 2, a metallic member 19, a fitting part 21, and a carrier and a frame of a printer. Further, since the outer periphery part of the yoke 2 together with the electromagnetic coil 3 is surrounded by the annular wall 8 of the protective cover 10, even though an operator is brought into contact with a dot printer head in the case where a box of the printer is opened for the purpose of replacement of an ink ribbon or the like, the operator can be protected from a possibility of a burn.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a dot printer head.

BACKGROUND TECHNOLOGY First, the invention described in Japanese Utility Model Application Publication No. 63-23041 is shown in FIG. A plurality of cores 102 holding electromagnetic coils 101 and a fulcrum portion 104 for an armature 103 are formed in the yoke 100. The armature guide 105 is provided with a fulcrum part 106 that presses the armature 103 against the fulcrum part 104, a leaf spring 106a that biases the armature 103 in the return direction, and a nose member 107 that protrudes toward the platen (not shown). It is being

A needle guide 109 that slidably holds a plurality of needles 108 is fixed to this nose member 107. These needles 108 are welded to the inner end of the armature i03. Further, a synthetic resin member 1 surrounding the yoke 100 together with the electromagnetic coil 101 is provided.
10 is embedded in the cover 111. This cover 11
1 is attached to the armature guide 105 with a screw 112. Therefore, the specific electromagnetic coil 10
1, the armature 103 is attracted by the core 102 and rotates, causing the needle 108 to collide with the platen. As a result, printing is performed.

Next, FIG. 4 shows the invention described in Japanese Patent Publication No. 55-500160. The annular yoke 113 is formed with a plurality of cores 115 that hold the electromagnetic coils 114 and a fulcrum part 117 of the armature 116, and a stopper holder 118 that holds a stopper 123 that determines the return position of the armature 116 is attached. It is being A support member 119 that holds the armature 116 freely
is provided with an elastic body 120 that presses the armature 116 against the fulcrum 117, and a spring 121.
The needle 122, which is biased in the return direction, is slidably held. In this dot printer head as well, by exciting a specific electromagnetic coil 114, the armature 116 is attracted to the core 115 and rotates, causing the needle 122 to collide with the platen. As a result, printing is performed.

Problems to be Solved by the Invention The invention described in Japanese Utility Model Application Publication No. 63-23041 has the problem that the yoke 1 is heated due to the excitation action of the electromagnetic coil 101.
00 is embedded in the cover 111 together with the synthetic resin 110. This increases the size of the cover 111. Also,
In order to promote the heat dissipation effect of the cover 111, it is necessary to make it from a metal material with high thermal conductivity, but when used for a long time, the heat generation temperature increases, and when the housing is opened to replace the ink ribbon, etc. There is a risk of touching the cover 111, which is dangerous. Insulating the area around the cover 111 from heat with another cover has the problem of making the structure even larger.

In the device described in Japanese Patent Publication No. 55-500160, heat is generated by the excitation action of the electromagnetic coil 114, but by attaching the yoke 113 to a carrier (not shown), the heat can be released from the yoke 113 to the carrier. It seems possible. However, since some heat is directly radiated from the electromagnetic coil 114, it is necessary to cover the yoke 113 together with the electromagnetic coil 114 with a protective cover made of synthetic resin or the like in order to protect the operator from heat when replacing the ink ribbon. . This increases the size of the dot printer head. In addition, the yoke 11 on the opposite side from the needle 122
If the dot printer head is attached to the carrier with the needle 122, the variation in the attachment angle will be magnified at the tip of the needle 122. As a result, even if the dimensional accuracy of the attachment portion of the yoke 113 to the carrier is improved, an adjustment mechanism for adjusting the printing position at the tip of the needle 122 must be provided, which increases costs.

Means for Solving the Problems A yoke having a plurality of cores equipped with electromagnetic coils is provided, and ends of a plurality of armatures facing the cores are connected to a needle slidably held in a needle guide, A protective cover made of synthetic resin is integrally formed with an armature guide portion that holds the armature in an up and down manner, a nose portion that holds the needle guide and projects toward the platen, and an annular wall surrounding the outer periphery of the yoke. At the same time, a metal member having a contact portion that contacts the yoke and a mounting portion that is located near the tip of the nose portion and is fixed to the carrier is provided.

The annular wall of the functional protective cover can cover the yoke together with the electromagnetic coil, and the heat generated from the electromagnetic coil can be conducted to the frame of the printer via the metal member in contact with the yoke and the carrier of the printer, This protects the operator from the risk of burns, and since the annular wall, nose section, and armature guide section are integrally formed, the number of parts can be reduced and downsizing can be achieved. Further, since the attachment portion formed on the metal member and attached to the carrier is located near the tip of the nose portion, it is easy to accurately maintain the position of the tip of the nose portion with respect to the platen.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. FIG. 1 is a longitudinal sectional side view, in which a plurality of cores 4 holding electromagnetic coils 3 are integrally formed on the outer periphery of an annular yoke 2 to which a PCC 10 is fixed. Further, a cover part 6 that covers the armature 5 facing these cores 4, a recessed armature guide part 7 formed in the cover part 6 and holding the armature 5 in a freely undulating manner, and the yoke 2
A protective cover 10 made of synthetic resin is provided which integrally forms an annular wall 8 surrounding the outer circumference of the electromagnetic coil section 3 together with a nose section 9 projecting toward a platen (not shown). The armature guide section 7 is formed with guide pieces 11 that guide both sides of the armature 5 and a cylindrical guide shaft 12 that passes through the center of the armature 5. A spring 13,14 is held which presses the armature 5 at. Further, the yoke 2 is formed with an edge-shaped fulcrum portion 15 that comes into contact with the armature 5. Furthermore, a plurality of needle guides 17 that slidably guide needles 16 welded to the inner end of the armature 5 are fixed to the nose portion 9. Further, the metal member 19 connected to the yoke 2 by the screw 18 includes a contact portion 20 for the yoke 2 and a mounting portion located near the tip of the nose portion 21 to be attached to a printer carrier (not shown). 21 are integrally formed. Furthermore, a stopper 22 that abuts the armature 5 is attached to the protective cover 10 with a screw 23. FIG. 2 is a plan view of the yoke 2. Three mounting holes 24 through which the screws 18 are passed are formed in the yoke 2 and arranged at equal intervals.

In such a configuration, the armature 5 is normally separated from the core 4 as shown in FIG. 1 by making the pressure of the spring 13 greater than the pressure of the spring 14. When a particular electromagnetic coil 4 is excited, the armature 5 is sucked by the core 4 and rotates about the fulcrum 15, causing the needle 16 to collide with the platen. The excitation action of the electromagnetic coil 3 generates heat, which is transferred to the core 4 and the yoke 2.
, metal member 19, mounting portion 21. conducted to the carrier and frame of the printer. In addition, since the outer periphery of the yoke 2 is surrounded by the annular wall 8 of the protective cover 1O together with the electromagnetic coil 3, if the printer casing is opened to replace the ink ribbon, etc., the dot printer head may be touched. It can also protect the operator from the risk of burns. Furthermore, by forming a large number of heat dissipation holes in the annular wall 8 so that the operator's fingers cannot fit therein, the heat dissipation effect can be promoted.

Moreover, since the heat of the yoke 2 can be dissipated to the carrier, the thickness of the annular wall 8 can be reduced, and
Since the annular wall 8, the armature guide portion 7, and the nose portion 9 are integrally formed, the number of parts can be reduced and the protective cover 10 can be made smaller.

Furthermore, since the attachment part 21 to the carrier is located near the tip of the nose part 9, the error in the attachment position will not be magnified at the tip of the nose part 9. can be determined accurately.

Effects of the Invention Since the present invention is configured as described above, the annular wall of the protective cover can cover the yoke together with the electromagnetic coil, and the heat generated from the electromagnetic coil can be transferred to the metal member in contact with the yoke and the carrier of the printer. This can protect the operator from the risk of burns, and the annular wall, nose section, and armature guide section are integrally formed. The number of parts can be reduced and downsizing can be achieved.Furthermore, since the mounting part formed on the metal member and attached to the carrier is located near the tip of the nose part, the position of the tip of the nose part relative to the platen can be accurately adjusted. And it can be easily determined.

FIG. 3 is a partially cutaway side view showing a conventional example, and FIG. 4 is a longitudinal sectional side view showing another conventional example.

Claims (1)

[Claims] a yoke having a plurality of cores equipped with electromagnetic coils;
A plurality of armatures each having needles connected to their tips and facing the core, a needle guide slidably holding the needles, an armature guide section holding the armatures in an up and down manner, and a platen holding the needle guides. a protective cover made of synthetic resin having a nose portion projecting to the side and an annular wall surrounding the outer periphery of the yoke;
A dot printer head comprising a metal member having a contact portion that contacts the yoke and a mounting portion located near the tip of the nose portion and fixed to the carrier.