JPH03114842A - Impact dot head - Google Patents

Abstract

PURPOSE:To improve workabilities of assembling and promote heat-release effects by forcing a core block having a required member of cores made of magnetic material, a solenoid being inserted into each of the cores, into an opening of a radiating member made of material having high thermal conductivity, wherein the diameter of said opening is slightly smaller than that of the circumference of the core block, so that the core block is fixed to the radiating member. CONSTITUTION:A plurality of cores 104 serving as magnetic pole are formed on a core block 101 made of ferromagnetic substances such as pure iron, silicon steel, etc., in such a manner that said cores protrude at regular intervals and are disposed in a radial manner, wherein a solenoid 110 is inserted into each of the cores 104. The surface area of a radiating member 106 made of material having high thermal conductivity and moldability such as aluminum, copper, etc., is made as large as possible so that the outer peripheries thereof are formed into fin-like configurations 107 to promote heat-release effects. And a base plate 113 is secured to the lower part of the member 106, while an opening 116 having a diameter slightly smaller than that of outer circumference of the block 101 is provided at the central part of said member, whereby the block 101 is pressed into said opening 116 and secured thereto. As a result, heat is radiated effectively to the atmosphere and machining cost can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an impact print head.

[Conventional Technique Vg] The impact dot head performs printing by selectively protruding printing wires by energizing or demagnetizing an electromagnetic coil.The required number of electromagnetic coils are inserted into the core arranged circularly in the core block. ing. This core block becomes extremely hot due to Joule heat from the electromagnetic coil and eddy currents from the core. As the temperature of the coil block increases, the winding resistance of the electromagnetic coil increases and the applied current decreases, resulting in a decrease in magnetic attraction force or demagnetization release force. As a result, printing energy decreases and print quality deteriorates. In addition, in order to prevent the electromagnetic coil from becoming extremely hot and burning out, a print quality of 1ilJ is required.1.
The heat generated by the core block has a large effect on the actual printing speed.

Conventionally, in order to reduce this heat generation, a radiator made of aluminum or the like was used to cover the entire print head and adhered with an adhesive such as silicone resin.

However, in the case of these conventional methods, the shape of the heatsink is extremely complex and requires molding by die-casting, making it an expensive component. Furthermore, since the thermal conductivity of the adhesive layer was low, it was not possible to effectively dissipate heat. Furthermore, in order to cure the adhesive, it was necessary to leave it for a long time or heat it, resulting in poor workability.

Another conventional technique is to provide a fin-shaped portion on the outer periphery of the core block.

In this case, the heat conduction efficiency is very good, but the shape of the core block becomes complicated. Therefore, it is difficult to mold using materials with poor moldability, such as silicon steel and permendile, which are high performance magnetic materials, resulting in extremely expensive parts.

Another problem was that the overall weight of the head increased because aluminum, which is lightweight and has good thermal conductivity, could not be used.

[Problems to be Solved by the Invention] The present invention has been made to solve the problems of the prior art, and its purpose is to provide a radiator structure that is inexpensive, easy to assemble, and extremely effective in heat dissipation. The object of the present invention is to provide an impact dot head with low heat generation.

[Means for Solving the Problems] That is, the impact dot head of the present invention performs printing by selectively protruding a plurality of printing wires by attracting or demagnetizing them using an electromagnetic coil. a core block having a required number of cores into which the electromagnetic coil is inserted;
and a heat dissipating member made of a material with good thermal conductivity and having an opening slightly smaller than the outer diameter of the core block, and the heat dissipating member is press-fitted into the core block and fixed.

[Examples] Hereinafter, the present invention will be described in detail based on Examples.

FIG. 1 is a diagram showing the configuration of a core block set, which is a feature of the present invention. 101 is a core block made of ferromagnetic material such as pure iron, silicon steel, permendur, etc. by forging lost wax method or metal injection method. On the front side of the core block 101, there is a lever swing control in the center part. A ring-shaped protrusion 103 that forms a magnetic path is protruded from the cylindrical protrusion 102 and further outside the cylindrical protrusion 102 . Surrounding this ring-shaped projection 103, a plurality of cores 104 forming magnetic poles are formed radially projecting at equal intervals on the outside thereof, and an outer circumferential projection 105 is formed projecting on the outside of these cores 104.

106 is a heat dissipation member made of a material with high thermal conductivity (good formability) such as aluminum or copper, and has a comb with a surface area as large as possible and a fin shape 107 on the outer periphery to enhance the heat dissipation effect.
is provided. At the bottom of the heat dissipation member 106, there is a prepared hole 10 for fixing a board 113, which will be described later, with a tapping screw.
9α, 109b are formed, and a core block 10 is formed in the center.
There is an opening 116 with a diameter slightly smaller than the outer circumference of the core block 101, and the core block 101 is press-fitted to the core block 101 without any gaps.

On the other hand, an electromagnetic coil 110 is inserted into each core 104 of the core block 101, and the coil terminal 111 is connected to the insulating plate 1.
Since the heat dissipating member 106 soldered to the substrate 113 attached to the back surface of the core block 101 via the heat dissipating member 106 has a flat plate shape, it can be formed extremely easily and with high precision by press working or the like.

Positioning pins 114α and 114b are press-fitted into the top surface of the cylindrical expansion portion 102 of the core block 1010, and these pins have a donut shape that comes into contact with the arm portion of the lever described later and dampens the repulsive force in the event of a collision. The damper 115 is positioned and fixed using positioning pins 114α and 114b.

FIGS. 2 and 3 show the core block set 20 described above.
1 is a diagram showing the overall structure of an impact dot head using No. 1.

The lever 202 consists of an arm portion 204 having a printing wire 205 fixed to its tip, and an armchair portion 206 that is attracted and biased by the core 205 . The lever 202 is provided with a fulcrum shaft 207 attached from the center to the armature different armature section 206@ in order to expand the swinging distance in the armature section 206 to allow the printing wire 203 to move.

The dish-shaped yoke 208 forms part of the magnetic path together with the disc-shaped yoke 209 (molded from a magnetic material). It is finished with an accurate thickness using a double-sided polishing method so that it can be supported at a predetermined height position on the front side, and there is a lever 2 on this side.
A slit 211 forming a swing space of 02 is formed radially.

On the other hand, the disk-shaped yoke 209 has a surface that corresponds to the planar shape of the lever 202 including the fulcrum shaft 207 so that each lever 202 can be positioned and held in opposition to the corresponding core 205. A plurality of substantially cross-shaped slits 216 are formed radially, and when the lever 202 is fitted into these slits, a fulcrum shaft is formed between the dish-shaped yoke 208 and the protrusion 218 of the frame 214. It is formed to be slightly thinner than the diameter of the fulcrum shaft 207 so that it can hold the fulcrum shaft 207.

On the other hand, the frame 214 includes a disk portion 215 facing the core block 210 and a nose portion 217 holding a guide holder 216. The disk portion 215 has a lever 202 near its periphery in cooperation with the dish-shaped yoke 208.
A plurality of protrusions 218 that hold the fulcrum shaft 207 are formed in a ring shape, and a depressed recess 220 of the spring holding member 219 is provided at the center of the protrusions 218 .

The arm portion 20 of the lever 202 is attached to the spring holding member 219.
A hole 221 is formed in the spring receiver at a portion corresponding to 4, and a coil spring 222 inserted therein biases the arm portion 204 of the lever 202 so as to constantly contact the damper 22, 3.

A wire guide 224 is attached to the guide holder 216 at its tip and in the middle, and is configured to slidably guide the printing wire 203 at the tip of the lever 202 so as to converge toward the tip of the 7-piece portion 217. has been done.

In the impact dot head configured as described above, when a pulse current is applied to one or more electromagnetic coils 225 selected by the print signal, the core 205
The armature portion 206 of the lever 202 is attracted by the magnetic flux flowing through the dish-shaped yoke 208 and the disk-shaped yoke 209, causing the printing wire 203 held at the tip to protrude in the axial direction to perform printing. When the application of the pulse current ends, the attractive force disappears, and the lever 2 is moved by the reaction force of the collision between the printing wire 203 and the platen (not shown) and the spring force of the coil spring 222.
02 returns to its original position. At this time, the heat generated in the electromagnetic coil 225 and the core 205 is transferred to the heat radiating member 226 that is in close contact with the core block 210 by press fitting, and is effectively radiated to the atmosphere from the surface whose area has been increased by the fin shape 212.

[Effects of the invention] Since the impact dot head configured in this way does not have a layer with poor thermal conductivity such as adhesive between the core block and the heat dissipation member, it can effectively dissipate the heat generated by the electromagnetic coil and core. Heat can be radiated to the atmosphere, improving cooling efficiency.

In addition, processing costs can be reduced because the heat dissipation member and core block can be shaped into simple shapes, and assembly workability is also good because no adhesive is used. Furthermore, using a material such as aluminum for the heat dissipating member contributes to reducing the weight of the entire head.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main part of the present invention, and FIGS. 2 and 3 are a side sectional view and a front view, respectively, showing an overall embodiment of the invention. 101.210... Core block i06,2.
26... Heat dissipation member 110.225...
Electromagnetic coil 113... Board 115.225... Dannogu 1... Core block set 2...
...... Lever 3 ...... Printing wire 7 ...... Fulcrum shaft 8 ...... Dish-shaped yoke 9 ...... ...Disc type yoke 4...Frame 6...Guide holder 9...Spring holding member 2...・・Coil spring 4・・・・・・Wire guide

Claims (1)

[Claims] In an impact dot head that performs printing by selectively protruding a plurality of printing wires by attracting or demagnetizing them with an electromagnetic coil, a core block made of a magnetic material and having a required number of cores into which the electromagnetic coils are inserted; and a heat dissipating member made of a material with good thermal conductivity and having an opening slightly smaller than the outer diameter of the core block, and the heat dissipating member is press-fitted into the core block and fixed. Impact dot head.