JPH06344635A - Thermal radiation structure of dot printing head - Google Patents

Abstract

PURPOSE:To obtain a dot printing head thermal radiation structure for raising a throughput by reducing the thermal interaction of a heat generated from a driving element with a heat generated from a driving circuit during the printing. CONSTITUTION:A head substrate 16 is securely bonded to a heat sink 31 so that an exposed part 19a of a heat spreader 19 mounted on the head substrate 16 for releasing a heat of a chip 18 of a wire driving circuit can be exposed from the heat sink 31 for releasing a heat of a demagnetizing coil 23 of a dot printing head 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in a serial printer having a print head for printing in a dot matrix system, reduces the thermal influence of heat generated by a drive circuit of the print head and heat generated by a drive element. The present invention relates to a heat dissipation structure of a dot print head.

[0002]

2. Description of the Related Art Conventionally, heat generated from a drive element of a dot print head during printing is transferred to a heat sink attached to the print head and released, and heat generated from a drive circuit which drives this drive element is not released. The heat spreader is attached to the head substrate on which the drive circuit is mounted.

Next, a conventional dot print head will be described with reference to FIGS. 6, 7 and 8. FIG. 6 is a sectional view showing a conventional dot print head, and FIG. 7 is a perspective view showing a head substrate. Further, FIG. 8 is a perspective view showing a mounting state of a conventional head substrate. In FIG. 6, the wire dot print head 1 is provided with a base 2, and a space yoke 3, a permanent magnet 4, a magnet yoke 5, a spacer 6, a leaf spring 7, and an armature yoke 8 are provided on an outer peripheral edge portion of the base 2. It is sequentially laminated. An armature 9 is attached to the free end of the leaf spring 8, and a print wire 10 is fixed to the tip of the armature 9. A sensor substrate 11 and a guide nose holder 12 are further laminated on the left side of the armature yoke 8. A guide nose 13 is attached to the guide nose holder 12, and a wire guide 14 is attached to the guide nose 13. The print wire 10 fixed to the armature 9 is guided by the wire guide 14 and protrudes from the print head 1.

A heat sink 15 is attached to the print head 1 so as to cover the print head 1, and heat generated from a degaussing coil 23 described later is radiated. On the side of the heat sink 15 facing the base 2, a head substrate 16 is provided with an adhesive 17 such as a silicon material.
Are glued together. The head substrate 16 has a chip 18 having an LSI circuit having a head drive drive element on one surface, and a heat spreader 19 for discharging heat generated from the chip 18 on the other surface. The heat spreader 19 is made of copper having high heat conductivity.
A space sheet 20 is provided between the head substrate 16 and the base 2 to prevent the magnetic flux generated from the permanent magnet 4 from leaking to the head substrate 16. And clamp 2
Reference numeral 1 denotes an outer periphery of the heat sink 15, which integrally fixes all the laminated members.

Next, the internal structure of the print head 1 will be described. The base 2 is provided with a plurality of cores 22,
A degaussing coil 23 is wound around the outer circumference of each core 22. The degaussing coil 23 is connected to the head substrate 16 described above. And both members 22 and 23 comprise an electromagnet. A thermistor 24 is provided in the center of the base 2 so as to detect a temperature rise inside the print head 1 due to heat generated from the degaussing coil 23 during printing. Further, at the time of non-printing, the magnetic flux of the permanent magnet 4 causes the core 22
A magnetic attraction force is generated between the armature 9 and the armature 9, so that the leaf spring 7 is attracted by the core 22 to bend, and strain energy is accumulated in the leaf spring 7.

Next, the printing operation and heat radiation effect of the print head 1 having the above structure will be described with reference to FIGS. First, the printing operation will be described. As described above, during non-printing, the armature 9 is attracted to the core 22 together with the leaf spring 7 by the magnetic flux of the permanent magnet 4. When a degaussing current is passed from the head substrate 16 to the degaussing coil 23 in this state, the permanent magnet 4 The attracting magnetic flux generated from the core 22 is canceled and the armature 9 attracted by the core 22 is separated from the core 22 by the strain energy of the leaf spring 7. The print wire 10 is guided by the wire guide 14 and protrudes from the print head 1. The tip of the projected print wire 10 is printed by hitting an ink ribbon (not shown) on a print sheet (not shown).

Next, the heat radiation effect will be described. When the degaussing coil 23 is energized, heat is generated from the degaussing coil 23 and the chip 18. The heat generated from the degaussing coil 23 is released from the heat sink 15 and the chip 18
The heat generated from the heat spreader 19 is released from the heat spreader 19.

[0008]

However, the wire dot printing head 1 having the above structure has the following problems. This will be described with reference to FIGS. 8 and 9. FIG. 9 is an explanatory view showing a conventional conduction route of heat generated from a chip, and arrows shown in the drawing indicate directions of release of heat generated from the chip 18.

In both figures, in order to increase the heat dissipation efficiency of the conventional heat sink 15, the portion of the heat sink 15 that directly contacts the outside air is increased and the head substrate 16 is covered so that the heat sink 15 and the heat spreader 19 are The parts were in contact with each other via an adhesive. When the adhesive 17 is made of a material having a heat transfer property such as a silicon material, the heat generated from the chip 18 is applied to the heat spreader 19
From the heat sink 15 to the adhesive 17 (in the direction of arrow A) or from the heat sink 15 to the inside of the print head 1 (in the direction of arrow B). When the heat generated from the tip 18 is transferred to the inside of the print head 1,
The temperature inside the print head 1 rises quickly, and the thermistor 24 for temperature detection detects an abnormal rise in temperature, and the printing operation must be temporarily stopped until the internal temperature drops to a certain value. As a result, there has been a problem that throughput is poor.

Since a part of the heat spreader 19 is covered with the heat sink 15, the heat spreader 1
The heat dissipation efficiency of No. 9 was very poor.

In view of the above-mentioned problems, the present invention provides a heat sink and a heat radiating section with a thermal effect in order to reduce mutual influence between heat generated from a chip and heat generated from inside a dot print head during a printing operation. It is an object of the present invention to provide a heat dissipation structure for a dot print head in which the throughput is improved by separating into two parts and the heat dissipation efficiency of the heat dissipation part is improved.

[0012]

In order to solve the above-mentioned problems, the present invention is directed to a drive circuit and a head substrate to which a heat dissipation portion for radiating heat generated from the drive circuit is attached, and the head substrate is fixed and driven. In a heat dissipation structure of a dot print head having a detector attached with a heat sink for radiating heat generated from an element and detecting a temperature change due to heat generated by a driving element, the heat radiating part and the heat sink are thermally separated Is.

Further, the heat dissipation portion may be exposed from the heat sink.

[0014]

During the printing operation, the heat generated from the driving element is radiated from the heat sink and the heat generated from the driving circuit is radiated from the heat radiating portion. Since the heat sink and the heat sink are provided separately from each other, the mutual influence of each heat is reduced,
Since the heat released from the heat radiating portion is not transmitted to the heat sink, the number of times the printing operation is temporarily stopped due to an abnormal rise in the internal temperature of the dot print head is reduced. As a result, the throughput can be improved.

Further, by exposing the heat dissipation portion from the heat sink, the heat dissipation efficiency of the heat dissipation portion is further increased.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to the drawings. Note that elements common to the drawings are given the same reference numerals. FIG. 1 is a sectional view showing a dot print head of a first embodiment according to the invention, and FIG. 2 is a perspective view showing a mounting state of a head substrate of the first embodiment.

In FIG. 1 and FIG. 2, the dot print head 3
The heat sink 31 attached so as to cover 0 fixes the head substrate 16 with the adhesive 17. And
The exposed portion 19a of the heat spreader 19 which is the heat radiating portion of the chip 18 is exposed from the heat sink 31. Therefore, the exposed portion 19a is in direct contact with the outside air. Further, as shown in FIG. 1, the adhesive 17 is not attached to the heat spreader 19.

Next, the operation of the dot print head 30 having the above structure will be described with reference to FIG. FIG. 3 is an explanatory view showing a conduction route of heat generated from the chip in the first embodiment,
The arrow shown in the figure indicates the direction of heat release from the chip 18. Since the printing operation is the same as the conventional one, the heat radiating action will be described here. By energizing the degaussing coil 23, heat is generated from the degaussing coil 23 and the chip 18. The heat generated from the degaussing coil 23 is applied to the heat sink 15
The heat generated from the chip 18 and generated from the chip 18 is discharged from the heat spreader 19 as indicated by the arrow C direction.
At this time, since the adhesive 17 is not attached to the heat spreader 19, the heat generated from the chip 18 is not transferred to the heat sink 31. Further, since the heat generated from the degaussing coil 23 is not transmitted from the heat sink 31 to the heat spreader 19 and the exposed portion 19a directly comes into contact with the outside air, the heat dissipation efficiency of the heat spreader 19 becomes higher than that in the conventional case.

Next, a second embodiment will be described with reference to FIGS. FIG. 4 is a perspective view showing a mounted state of the head substrate of the second embodiment, and FIG. 5 is a perspective view showing the head substrate of the second embodiment. In both figures, the uneven portion 43 is formed on the exposed portion 42 a of the heat spreader 42 of the head substrate 41 provided on the dot print head 40. The other structure is similar to that of the first embodiment.

Next, the operation of the dot print head 40 having the above structure will be described. Since the printing operation and the heat radiation operation of the degaussing coil 23 are the same as those in the first embodiment, the heat radiation action of the chip 18 will be described here. During printing, the heat generated from the chip 18 is applied to the exposed portion 4 of the heat spreader 42.
It is emitted from 2a and the uneven portion 43. Since the exposed portion 42a of the heat spreader 42 has an uneven shape, the area directly exposed to the outside air is larger than that of the exposed portion 19a of the first embodiment, and the heat dissipation efficiency is further improved. At this time, since the adhesive 17 is not attached to the heat spreader 42, the heat generated from the chip 18 is not transferred to the heat sink 31.

By the way, in the second embodiment, the exposed portion 42a is formed.
Two concave and convex portions 43 are provided in the above, but the number is not limited to two.

In the first and second embodiments, in order to provide the heat sink 31 and the heat spreaders 19 and 42 separately from each other thermally, a cutout is provided in the heat sink 13 to expose the heat spreaders 19 and 42 from the heat sink 13. However, the heat radiation efficiency of the heat sink 13 is not lowered by providing the notch in the heat sink 13.

[0023]

As described above in detail, according to the present invention, the heat sink for radiating the heat generated by the driving element during the printing operation and the heat radiating portion for radiating the heat generated by the driving circuit are thermally separated. Since the heat is generated from the drive circuit, the heat generated from the drive circuit is not transferred to the inside of the dot print head and the temperature rise inside the head is not accelerated. As a result, the throughput is improved as compared with the conventional one. Further, heat generated from the driving element is not transferred to the driving circuit. Further, since the exposed portion of the heat radiating portion is formed in a concavo-convex shape, the heat radiating efficiency is further improved, so that the material of the heat radiating portion can be changed from copper to aluminum. As a result, costs can be kept lower.

[Brief description of drawings]

FIG. 1 is a sectional view showing a dot print head according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a mounted state of the head substrate of the first embodiment.

FIG. 3 is an explanatory diagram showing a conduction route of heat generated from a chip.

FIG. 4 is a perspective view showing a mounted state of a head substrate of a second embodiment.

FIG. 5 is a perspective view showing a head substrate.

FIG. 6 is a cross-sectional view showing a conventional dot print head.

FIG. 7 is a perspective view showing a head substrate.

FIG. 8 is a perspective view showing a mounted state of a conventional head substrate.

FIG. 9 is an explanatory diagram showing a conduction route of heat generated from a chip.

[Explanation of symbols]

 16 Head Substrate 18 Chip 19 Heat Spreader 30 Dot Print Head 31 Heat Sink 40 Dot Print Head 42a Exposed Part 43 Uneven Part

Claims (3)

[Claims] 1. A drive circuit and a head substrate to which a heat radiating portion for radiating heat generated from the drive circuit is attached, and a heat sink for fixing the drive element and radiating heat generated from the degaussing coil are attached to the drive circuit. In a heat dissipation structure of a dot print head having a detector for detecting a temperature change due to generated heat, a heat dissipation structure of the dot print head is characterized in that a heat dissipation part and a heat sink are thermally separated. 2. A heat dissipation structure for a dot print head, comprising: a drive circuit; and a head substrate having a heat radiating section for radiating heat generated by the drive circuit, and a heat sink for radiating heat generated by the driving element. A heat dissipation structure for a dot print head, characterized in that the heat dissipation part is exposed from the heat sink. 3. The heat dissipation structure for a dot print head according to claim 2, wherein the exposed part of the heat dissipation part has an uneven shape.