JPH04246547A - Impact dot head - Google Patents

Abstract

PURPOSE:To stabilize the movement of levers for improving the quality of printing and the durability by providing protrusions on lever holders to keep the levers from rotating. CONSTITUTION:An impact dot head consists of two or more levers 1, a frame 6 having two or more cores 5 that compose a magnetic circuit, pivot holding springs 2 that elastically hold pivots 1a of the levers 1, and lever holders 4 which hold the pivot holding springs 2. Protrusions 4a are provided on the lever holders 4 to keep the levers 1 from rotating.

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.

0002

2. Description of the Related Art As shown in FIG. 5, a lever A of a conventional impact dot head is pressed only by a fulcrum holding spring B that elastically holds a fulcrum portion Aa of the lever A.

However, if the platen gap (distance from the printing wire C in the standby position to the platen) is large, the amount of movement of the printing wire C when the lever A is attracted is large, and the surface of the lever A facing the core D is One side Ab comes into contact with the core D, and the lever A rotates using the one side Ab as a fulcrum, so the fulcrum part Aa of the lever A rotates toward the lever holder E.
It rises from the surface of frame F. Due to this large lifting amount, the fulcrum portion Aa of the lever A collides with the frame F when returning, and this repeated collision causes the frame F to wear out.

[0004] In the impact dot head, this drawback not only significantly reduces the durability, but also
There was a problem in that the behavior of the printer became unstable, resulting in printing defects such as missing dots and ribbon catching.

As a countermeasure for this problem, there is a method of arranging a spacer G with excellent wear resistance between the frame F and the lever A, as shown in FIG. The amount of lift of the fulcrum portion Aa from the spacer G is large as described above, and the fulcrum portion Aa of the lever A collides with the spacer G when the lever A returns. Therefore, although the wear of the frame F is reduced compared to when the spacer G is not provided, the spacer G wears and breaks, which not only significantly reduces the durability, but also causes the lever A to wear out and break.
There was a problem in that the behavior of the printer became unstable, resulting in printing defects such as missing dots and ribbon catching.

[0006]

The problems to be solved are that durability is reduced and the behavior of lever A becomes unstable, resulting in printing defects such as missing dots and ribbon catching.

[0007]

[Means for Solving the Problems] The impact dot head of the present invention has a frame having a plurality of levers and a plurality of cores constituting a magnetic circuit, in order to have excellent durability and stabilize the behavior of the lever. In an impact dot head having a fulcrum presser spring that elastically holds the fulcrum part of the lever and a lever holder that holds the fulcrum presser spring, the lever holder is provided with a protrusion that stops the rotation of the lever. Features.

[0008]

[Embodiment] Fig. 1 is a diagram showing an embodiment of the present invention, in which a predetermined number of coils 11 are incorporated into a frame 6 having a plurality of cores 5, and a lever 1 is attached to the inner circumference of the frame 6, which returns after printing is completed. A spring holder 13 having a return spring 10 is incorporated therein. On the outer periphery of the frame 6,
A yoke 8 having a recess corresponding to each lever 1 is brought into contact with the outer circumference of the ring-shaped plate. The side yoke 9 has a shape that holds the lever 1 with a predetermined number of grooves, and the yoke 8
It forms part of the magnetic circuit in cooperation with the magnetic circuit. frame 6
A spacer 3 made of a metal plate is sandwiched between the yoke 8 and the yoke 8. A printing wire 7 is fixed to one end of the lever 1, and the lever fulcrum portion 1a is pressed by a spring portion 2b of a fulcrum presser spring 2. The fulcrum presser spring 2 is composed of an elastically deformable spring portion 2b and a connecting portion 2a, and is assembled so as to come into contact with the lever holder 4.

[0009] The lever holder 4 has a damper 12 for absorbing the energy when the lever 1 returns, and is further assembled to the nose 16 by means of a fixing spring 15 via a reinforcing plate 14. The lever holder 4 has a protrusion 4a that stops the lever 1 from rotating at the maximum allowable position when the lever 1 rotates toward the lever holder 4 side.

When the coil 11 is driven, a magnetic circuit is formed by the frame 6 having the core 5, the yoke 8, the side yoke 9, and the lever 1, and due to the magnetic attraction force, the lever 1 is moved around the fulcrum portion 1a, as shown in FIG. As shown in FIG. 2, the printing wire 7 fixed to one end of the lever 1 rotates through the printing paper (not shown) until it collides with the platen (not shown), forming dots on the printing paper.

After the printing is completed, the lever 1 having the printing wire 7 returns to its original position due to the repulsive force from the platen (not shown) and the spring force of the return spring 10, and the energy of the return process is absorbed by the damper 12, and as shown in FIG. 3, it is held in the standby position.

In the above series of operations, the moving distance of the printing wire 7 is determined by the platen gap (the distance from the printing wire 7 at the standby position to the platen). FIG. 2 shows the position of the lever 1 during printing with an appropriate platen gap. The lever 1 rotates about the lever fulcrum 1a, and the printing wire 7 fixed to the lever 1 is connected to the printing paper (not shown). It stops when it collides with a platen (not shown) through the platen (not shown). At this time, the lever 1 contacts the core 5, but one side 1b of the surface facing the core 5 stops at a position where it does not contact the core 5, and the back surface 1c of the lever 1 also contacts the protrusion 4a of the lever holder 4. Stop at a position where they do not touch each other.

FIG. 4 shows a printer in which the platen gap is manually operated by the user, and when a single sheet of paper is printed with the platen gap set large to print on copy paper, that is, when the platen gap is large, This shows the position of the lever 1 during printing. The lever 1 rotates about the lever fulcrum part 1a, one side 1d of the surface facing the core 5 contacts the core 5, and rotates about the one side 1d as a fulcrum. . At this time, the lever fulcrum portion 1a separates from the spacer 3 and floats toward the lever holder 4 side.

Further, one side 1b of the surface facing the core 5 is brought into contact with the core 5, and further, by rotating around this side 1b as a fulcrum, the other side 1d of the surface facing the core 5 and the lever fulcrum portion 1a are rotated. stands out.

However, the impact dot head of the present invention has a protrusion 4 on the lever holder 4 that stops the lever 1 from rotating at the maximum allowable position.
Since a is arranged, when the platen gap is large,
Even if the lever 1 rotates using the side 1b of the surface facing the core 5 as a fulcrum, the back surface 1c of the lever 1 will touch the protrusion 4a of the lever holder 4 at the maximum rotational position allowable for durability and print quality. When it makes contact, lever 1 can be stopped.

Therefore, the amount of lift of the lever fulcrum portion 1a from the spacer 3 can be reduced, and the energy of the lever fulcrum portion 1a colliding with the spacer 3 when the lever 1 returns to the standby position after printing is completed can be reduced. It is possible to realize an impact dot head with little wear on the spacer 3, excellent durability, stable behavior of the lever 1, and no printing defects such as missing dots or ribbon catching.

[0017]

As described above, the impact dot head of the present invention includes a plurality of levers, a frame having a plurality of cores constituting a magnetic circuit, a fulcrum holding spring that elastically holds the fulcrum of the lever, It has a lever holder that holds the fulcrum presser spring, and a protrusion that stops the lever from rotating is provided on the lever holder, so even if the platen gap is large,
The amount of lift of the lever fulcrum can be reduced, and the energy that collides with the spacer of the lever fulcrum upon return can be reduced. Therefore, wear of the spacer is reduced and durability is excellent, and lever behavior is stabilized, and printing defects such as missing dots and ribbon catching can be solved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing an embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing an embodiment of the present invention.

FIG. 5 is a partial sectional view showing a conventional example.

FIG. 6 is a partial sectional view showing a conventional example.

[Explanation of symbols]

1 Lever 1a Lever fulcrum part 2 Fulcrum holding spring 3 Spacer 4 Lever holder 4a Protruding part 5 Core 6 Frame 7 Printing wire 8 York 9 Side yoke 10 Return spring

Claims (1)

[Claims] 1. An impact impactor having a frame having a plurality of levers, a plurality of cores constituting a magnetic circuit, a fulcrum presser spring that elastically holds a fulcrum portion of the lever, and a lever holder that holds the fulcrum presser spring. An impact dot head, characterized in that the lever holder is provided with a protrusion that stops the lever from rotating.