JPH068480A - Impact dot head - Google Patents

Abstract

PURPOSE:To prevent the burning of a coil in an impact dot head. CONSTITUTION:Temperature sensing elements 30 are printed on a print base 16 in a manner that the distances from respective cores 1 are all equal. The incorporating properties of the temperature sensing elements 30 are improved by the arrangement, and the distances between a plurality of cores 1 and the temperature sensing elements 30 are made small and uniform to sense the temperature accurately and prevent the burning of a coil 2.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional technique, for example, the actual development sho 60
An impact dot head described in Japanese Patent No. 9143 is known. The impact dot head disclosed therein has a structure as shown in FIG. 5, and includes a printing wire 106, a wire guide 110 for guiding the printing wire 106, a core 101, a coil 102 wound around the core 101, and a coil. Space 131 between 102, etc.
Is to have. Here, the temperature detection resistance wire 130 for temperature detection was provided on the inner surface of the frame 118 of the impact dot head body so as to be in common contact with all the coils 102.

[0003]

However, in the impact dot head using such a conventional technique, the temperature detecting resistance wire 130 is connected to the frame 118 and the coil 1.
No. 02 is installed in a narrow position without a guide member for positioning, so that the assembling property is poor and the positional relationship with the coil 102 is likely to be inaccurate. Therefore, the number of assembling steps is increased, and the temperature cannot be accurately detected. There was a problem that it could lead to burnout.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an impact dot head which solves the above problems and has good assemblability and which is not burned by accurate temperature detection.

[0005]

In order to solve the above problems, an impact dot head of the present invention comprises a frame provided with a plurality of cores around which a coil is wound and an armature arranged so as to face the suction surface of the cores. Another feature of the impact dot head is that the temperature detection element is printed at a position equidistant from a plurality of cores on a printed circuit board that is adjacent to the frame provided with the core and is connected to the coil.

Further, the impact dot head of the present invention is characterized in that independent temperature detecting elements corresponding to a plurality of cores are printed.

[0007]

With the above structure, the temperature detecting element can be installed at a position where the thermal resistance is low and equidistant from a plurality of heat sources.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a three-view drawing of an impact dot head according to a first embodiment of the present invention. A wire guide 14 provided with a plurality of holes for guiding and supporting a plurality of printing wires 6 in a reciprocating manner is arranged at the tip of the nose 13. A drive unit for driving the print wire 6 is provided behind the nose 13, and a radiator 15 for dissipating internally generated heat to the atmosphere is provided on the outer periphery of the drive unit. In addition, there are a printed circuit board 16 for guiding a print signal to a driving unit and a connector 17 for connecting a cable (not shown).

FIG. 2 is a sectional view taken along line AA in FIG.
Inside the impact dot head, there is a frame 18 in which a plurality of cores 1 made of a magnetic material are arranged on the circumference. An armature 3 made of a magnetic material faces each core 1 and a lever 4 including the armature 3 is provided. Is rotatably supported about a fulcrum shaft 5, and is pressed against a lever holder 8 by a return spring 7 in a standby state. The printing wire 6 is fixed to the tip of the lever 4 by brazing. A coil 2 for generating a magnetic attraction force is wound around each core 1, and a coil terminal 9 at the tip of the coil 2 is soldered onto a printed board 16 through a through hole of a frame 18. The printing wire 6 presses the printing paper 20 against the platen 21 via the ink ribbon 19 for printing.

FIG. 3A is an exploded perspective view of the printed board 16, frame 18, coil 2 and connector 17 used in the first embodiment of the impact dot head of the present invention. On the surface of the printed circuit board 16 in contact with the frame 18, a temperature detection element 30 made of metal or thermistor powder whose electric resistance changes according to temperature change is printed so as to pass through the back surfaces of all the cores 1, and the solder specified by the connector 17 is used. Since the wiring is made up to the mounting position, the temperature detecting element can be easily installed at an accurate position. On the upper layer of the temperature detecting element 30, there is a thin insulating layer (not shown) to prevent conduction with the frame 18. The through hole 31
Is a through hole for the coil terminal 9, and the through hole 33 is a through hole for the connecting terminal of the connector 17, as will be described later.

FIG. 3B is a back surface of the printed circuit board 16 of the first embodiment described above, and a through hole 31 for fixing the coil terminal 9 at the tip of the coil 2 by soldering.
There is a land portion 34. On the back surface of the portion to which the connector 17 is connected, there are through holes 33 and lands 36 for fixing the terminals of the connector 17 by soldering, and are electrically connected by the printed wiring 35. The connector 17 solders its connection terminal to the land portion 36 through the through hole 33. Next, the printing operation using the impact dot head of the present invention will be described with reference to FIG.

When a print signal is input to the coil 2, the core 1 made of a magnetic material is magnetized and a magnetic attraction force is generated between the armature 3 and the core 1. This magnetic attraction force causes the lever 4 including the armature 3 to rotate about the fulcrum shaft 5 as the center of rotation.
Begins to rotate while flexing the return spring 7. At this time, the printing wire 6 fixed to the tip of the lever 4 starts moving toward the platen 21, and the tip of the printing wire 6 collides with the printing paper 20 via the ink ribbon 19 to form dots. Next, the lever 4 has the printing wire 6 and the platen 2
The repulsive force received at the time of collision with 1 and the restoring force of the return spring 7 that has been deflected start a rotational movement in the opposite direction, collide with the lever holder 8 and return to the standby position, and one printing cycle is completed.

At this time, a large amount of heat is generated from the coil 2, but this heat is conducted from the core 1 to the frame 18, and the temperature of the frame 18 rises together with the coil 2. The printed circuit board 16 is in close contact with the frame 18, and the temperature detection elements 30 on the printed circuit board 16 are equidistant from the plurality of cores 1. Further, between the coil 2 and the temperature detecting element 30, there is a frame 18 having high thermal conductivity and a thin and uniform insulating layer (not shown), so that the thermal resistance is low and the temperature of the coil 2 can be sensed sensitively. Further, since the temperature detecting elements 30 are equidistant from all the cores 1, the temperature can be accurately detected from any of the cores 1.

The temperature detecting element 30 is connected to a temperature detecting circuit in the main body of the impact dot printer through a cable (not shown) and controls the drive speed of the impact dot head when the temperature exceeds a preset temperature to suppress the temperature rise of the coil 2 and burn it out. It is configured to prevent.

FIG. 4 shows a back view of a printed circuit board 16 of another embodiment used in the impact dot head of the present invention. Since the printed circuit board 16 of this embodiment is installed at the same position as that of the embodiment shown in FIGS. 1 to 3, detailed description thereof will be omitted. As shown in the figure, in this embodiment, the temperature detecting element 30 is independent of each core 1. As a result, the coil temperature can be accurately detected by performing partial temperature detection.

[0017]

As described above, according to the present invention, since the temperature detecting element is printed on the printed circuit board adjacent to the frame, the assemblability is improved, and the temperature of each coil can be accurately detected. This has the effect of avoiding coil burnout.

[Brief description of drawings]

FIG. 1 is a trihedral view showing an embodiment of an impact dot head of the present invention.

FIG. 2 is a sectional view of the impact dot head of the present invention shown in FIG. 1, taken along the line AA.

FIG. 3A is a printed circuit board 16, a frame 18, a coil 2 used in the impact dot head of the present invention,
It is a disassembled perspective view of the connector 17, (b) is a back view of a printed circuit board.

FIG. 4 is a rear view showing a printed circuit board 16 used in another embodiment of the impact dot head of the present invention.

FIG. 5 is a cross-sectional view of a conventional impact dot head.

[Explanation of symbols]

 1 core 2 coil 3 armature 4 lever 5 fulcrum shaft 6 printing wire 7 return spring 8 lever holder 9 coil terminal 13 nose 14 wire guide 15 radiator 16 printed board 17 connector 18 frame 19 ink ribbon 20 printing paper 21 platen 30 temperature sensing element 31, 33 Through holes 34, 36 Land portion 35 Printed wiring 40 Temperature detection element 101 Core 102 Coil 106 Printing wire 110 Wire guide 118 Frame 130 Temperature sensing resistance wire for temperature 131 Space

Claims (2)

[Claims] 1. An impact dot head comprising a frame provided with a plurality of cores around which a coil is wound and an armature arranged so as to face a suction surface of the core, adjacent to the frame provided with the core, An impact dot head, wherein a temperature detection element is printed at a position equidistant from the plurality of cores on a printed circuit board connected to the coil. 2. The impact dot head according to claim 1, wherein the independent temperature detecting elements are printed corresponding to the plurality of cores.