JPH02266954A - Impact dot head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field 1 The present invention relates to impact dot heads.

[Prior Art] Conventionally, as shown in Fig. 5, as a coil for an impact dot head, a conducting wire is wound around a coil bobbin having a cylindrical portion with a uniform wall thickness, and both ends of the conducting wire are connected to coil terminals. Mills with Karame solder plating are commonly used.

Further, in order to increase the coil volume, some impact dot heads use a coil formed only of conductive wire without a coil bobbin as shown in FIG. 7.

[Problems to be Solved by the Invention] However, since the coil shown in FIG. 7 is formed only of conductor wire, the tip of the coil conductor cannot be positioned at the time of assembly. must be inserted. Furthermore, since soldering to a board sometimes requires removing the covering of the conductive wire, workability is extremely poor and low-cost assembly is impossible. Furthermore, since the core and the conducting wire directly rub against each other when inserted into the core, the covering of the conducting wire is likely to peel off, and treatment such as applying an insulating coating to the core is necessary.

Furthermore, in recent years there has been a strong demand for smaller impact dot heads, and frames with smaller core spacing have come to be used to achieve higher integration.

However, in a coil using a coil bobbin consisting of a cylindrical part with a uniform wall thickness as shown in Fig. 5, the number of turns of the coil must be reduced by the thickness of the cylindrical part, which is difficult to achieve at low currents. Impact dot heads that cannot obtain the necessary printing energy and cannot wind the required number of coil turns due to insufficient space between adjacent coils have no choice but to flow large currents, which generates a large amount of heat due to Joule loss. This has caused the problem that high-density printing cannot be performed for a long time.

Further, when the wall thickness of the coil bobbin is made small over the entire circumference, there are problems such as poor molding due to insufficient filling and poor assembly due to insufficient rigidity due to the thin wall.

Therefore, the present invention is intended to solve these conventional problems.The purpose of the present invention is to be highly integrated, compact, and capable of printing with low power consumption, with excellent workability, and capable of long-term high-density printing. The purpose is to obtain an impact dot head that can be used.

[Means to solve the problem]

In order to solve the above-mentioned problems, the impact dot head of the present invention has the following features: 1. The thickness of the cylindrical part inserted into the core of the coil bobbin is different for the part facing the adjacent coil and the other parts. 2. The impact dot head according to claim 1, characterized in that the thickness of the cylindrical portion has a shape that changes smoothly.

C implementation example 1 Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a sectional view of the impact dot head of the present invention. As shown in FIG. 1, the dot head is assembled by overlapping a nose 1, a frame 2, a yoke A3, a yoke B4 and a lever holder 5. Said nose l
A tip guide 6 and an intermediate guide A7 are attached to the
The tip guide 6 arranges the wires 8 in a line.

An insulating sheet 9 is provided between the nose 1 and the frame 2.
A printed wiring board 10 is disposed via the .

The frame 2 has a cylindrical shape, and a flat bottom surface 11 is formed on one side thereof. A plurality of cores 12 are erected from the bottom surface 11.

Through holes 13 are formed in the bottom surface ti around these cores 12 . A spring holder 15 is attached to the inner circumference of the core 12 with an intermediate guide B14 interposed therebetween.

The spring holder 15 is equipped with the same number of return springs 17 as the cores 12. Next, a coil 17 is attached to each of the cores 12. This coil 17 has a coil terminal portion 18 and is inserted into a through hole 13 formed in the bottom surface 11 of the frame.

Next, on the upper surface of the frame 2, a yoke A3, a yoke B
4 is attached, and a lever 19 is attached which faces the core 12 through the yoke A3 and yoke B4. The wires 8 are fixed to the tips of these levers 19, and are urged in the return direction by the return springs 16. Further, a lever holder 5 is attached so as to be in contact with the upper surface of the spring holder 15, and a damper rubber 20 is attached to the center portion of this lever holder 5. The tip of the lever 19 is brought into contact with this damper rubber 20 with a damper spacer 21 interposed therebetween.

In such a configuration, the coil 17 connected to the printed wiring board 10 is selectively energized according to the print signal. The magnetic flux excited by the coil 17 passes through a loop returning to the frame core part 12 through the frame core part 12, the frame bottom surface 11, the frame cylindrical part 22, the yoke A3, the yoke B4, and the lever 19. As a result, a magnetic attraction force is exerted between the frame core portion 12 and the first flange 19, causing the lever 19 to move forward and applying an impact force to the recording paper by the wire 8 to form a dot.

In the impact dot head constructed in this way, 24 cores 12 are cylindrically arranged upright from the bottom surface 11 of the frame. In order to make the impact dot head small, lightweight, and high speed, the distance from the center to the core 12 is determined by lever 19.
On the other hand, since the attraction area of the core 12 is a magnetic path member that constitutes a magnetic circuit, it cannot be made small in terms of magnetic efficiency. Therefore, the number of turns of the coil 17 is determined by the distance between the cores 12. It is not possible to increase the number of turns.

Note that the arrangement of the core 12 does not need to be on a complete circumference (,
It can be oval or diamond shaped.

In this embodiment, in order to maximize the cross-sectional area of the core 12 and the distance between the cores 12 as shown in FIG.
The angle of fan 2 is about 15 degrees (24 divisions of 360 degrees), but in this embodiment, the distance between the cores 12 is only about 1.7 mm.In the conventional coil bobbin, as shown in FIG. In addition, the wall thickness of the bobbin cylindrical portion 23 is uniform, and a thickness of about 0.3 mm is generally required from the viewpoint of moldability of the bobbin 25 and ensuring the rigidity of the bobbin 25. Therefore, the width that the conductor 24 can be wound is approximately 0.55 mm (=1.7
÷2-0.3), but according to this embodiment, Figs. 2 and 3
As shown in the figure, the thickness of the surface facing the adjacent coil 17 was 0.12 mm to 0.18 mm, and the thickness of the other surfaces was 0.3 mm to 0.5 mm. Wall thickness from 0.3mm to 0
．． The portion with a width of 5 mm is a portion with sufficient space as shown in FIGS. 1 and 2. This is a lever
Since the radial layout is determined by mechanical and structural constraints such as the return spring and lever fulcrum holder, sufficient space can be used for the coil.

Therefore, without reducing the formability and rigidity of the bobbin 25, the winding width of the conductive wire can be increased by 0.18 mm to 0.12 mm by reducing the thickness of the bobbin on the surface facing the adjacent core. Magnetomotive force is proportional to the product of the number of turns of the conductor and the current flowing through the conductor, so if the same magnetomotive force is obtained, the number of turns of the conductor increases λ
Therefore, the current can be reduced, and a given printing energy can be obtained with a low current. In the case of the above example, the peak current value could be reduced from the conventional value of 1.4A to 0.97A.

In addition, by lowering the current value, heat generation is also kept low.
Furthermore, since the core 12 and the conductor 24 are closer together, the coil 1
The heat generated in step 7 is quickly transferred to the core 12, thereby preventing the coil 17 from burning out during continuous printing.

In the impact dot head of this embodiment, the heat dissipation characteristics are improved by 1.5 times compared to the conventional head.

FIG. 4 shows an embodiment of claim 2. As shown in FIG. 4, the coil bobbin 25 of this embodiment has a wall thickness of the cylindrical portion 23 near the center of the frame 2, and an outer shape of the winding portion of the conductive wire 24 in an arc shape. It changes smoothly like this. Generally, when winding the conductive wire 24 around the coil bobbin 25, if there is an edge or a portion with a small l ratio in the cylindrical portion 23, the winding is likely to become slack or disordered there, and for this reason, the winding becomes thick and the number of windings is limited. Coil bobbin 2 of this example
5 is a conductor 24 in which the outer shape of the winding part of the conductor 24 is arc-shaped, so that it is difficult for the winding to thicken due to sagging or disordered winding.
The shape is such that the effect of increasing the number of turns can be fully utilized.

[Effects of the Invention] In the impact driver I/head configured as described above, the number of coil turns can be increased because the wall thickness of the coil bobbin cylindrical portion on the surface facing the adjacent coil where space is limited is made thinner. Therefore, it is possible to obtain the printing energy necessary for printing with a low current.

In addition, since the core and conductor are thinner, they are closer to each other, improving heat conduction and allowing the heat generated in the coil to escape to the core (this makes it possible to print at high density for a long time). .

The wall thickness of the cylindrical part of the coil bobbin in areas where there is sufficient space is increased to the extent that it does not affect the number of coil turns, so there is no buckling or deformation when inserting the coil due to lack of coil bobbin rigidity, and the formability of the coil bobbin is also improved. The thick part becomes the runner, so it will not be damaged.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the inbatoku dot head of the present invention. FIG. 2 is a partially sectional perspective view of the coil according to claim 1 of the present invention. FIG. 3 is a plan sectional view of a frame in which a core equipped with a coil according to the embodiment of the present invention shown in FIG. 2 is arranged. FIG. 4 is a plan sectional view of the coil according to claim 2 of the present invention. FIG. 5 is a partially sectional perspective view showing a conventional example of a coil having a conventional coil bobbin. FIG. 6 is a cross-sectional view of a frame on which a coil is mounted, to which the coil of the conventional example shown in FIG. 5 is mounted. FIG. 7 is a partially sectional perspective view showing a conventional example of a coil without a coil bobbin. 1 ・ ・ 2 ・ ・ 3 ・ ・ 4 ・ ・ 5 ・ ・ 6 ・ 7 ・ ・ 8 ・ ・ 9 ・ ・ IO・ ・ 1 ・ ・ 1 2 ・ ・ 13 ・ ・ 1 4 ・ ・ 1 5 ・ ・l 6 ・ ・ 17 ・ ・ 18 ・ ・ Nose frame yoke A Yoke B Lever holder tip guide intermediate guide A Wire insulation sheet Printed wiring board frame bottom core through hole intermediate guide B Spring holder return spring coil coil terminal part l 9 ・ 20 ・2 l ・ 22 ・ 23 ・ 24 ・ 25 ・ Lever damper Rubber damper Spacer frame Cylindrical part bobbin Cylindrical part Conductor coil bobbin Applicant: Seiko Epson Corporation

Claims (2)

[Claims] (1) A plurality of cores each having an electromagnetic coil wound with a conductive wire inserted into a coil bobbin are arranged in a ring, and the cores are arranged opposite to the core by utilizing the electromagnetic force generated by energizing the electromagnetic coil. An impact dot head for printing by driving an armature, characterized in that the wall thickness of the cylindrical part inserted into the core of the coil bobbin is different for the part facing the adjacent coil and the other parts. . (2) The impact dot head according to claim 1, wherein the thickness of the cylindrical portion is shaped to change smoothly.