JPS6253844A - Printing head - Google Patents

Abstract

PURPOSE:To raise the quality of printing by using a resin sheet for the stopper of an armature. CONSTITUTION:A positioning hole is provided in the stopper 4 of a resin sheet. A supporter 8 and a cover 7 are fixed with a presser spring 6 to the stopper 4. An armature 1 is pressingly contacted with the stopper 4 by a spring 5. Since a synthetic resin sheet is used for the stopper 4, the rocking stroke of printing wires is uniform in the circumferential direction, and therefore printing can be concurrently made by a plurality of printing wires, when the wires can reach a printing paper at the same time; thereby, avoiding the bias of dots due to the difference of arrival ties of the wires. Also, because of uniform strokes, the final speeds of the wires can be equalized and uniform printing can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a print head for an impact dot matrix printer.

2. Description of the Related Art In recent years, inexpensive flapper-integrated print heads have come to be used as print heads for dot printers.

Two examples of conventional print heads will be described below.

Figure 3 is a cross-sectional view of a conventional print head, where ■ is the armature, 2 is a print wire welded and fixed to the movable end of the armature 1, and 3 is a print wire that attracts the armature 1 by magnetic force and prints on the print wire 2. It is an electromagnet that allows The armature 1 can swing around the outer end of the electromagnet 3 as a fulcrum. Reference numeral 9 denotes a resin-molded stopper having the shape shown in FIG. 4, and the armature 1 is always pressed against the stopper 9 by a spring 5. Reference numeral 6 denotes a presser spring that presses the armature 1 against the fulcrum of the electromagnet 3, 7 a cover for the print head, and 8 a support member that presses the stopper 9 and the presser spring 6 against the cover 7.

The operation of the print head configured as described above will be described below.

First, the armature 1, which was in pressure contact with the stopper 9 by the spring 5 in the initial state, is attracted by the electromagnet 3 being excited, and swings around the outer end of the electromagnet 3 as a fulcrum.
At the same time, the printing wire 2 fixed by welding to the movable end of the armature 1 operates to perform a printing operation.

Next, when the electromagnet 3 is energized, the armature 1 and the printing wire 2 are pushed back by the spring 5, and the stopper 9
It collides with the object and returns to its initial state.

Next, FIG. 5 is a sectional view of another conventional print head.

1 is the armature, 2 is the printing wire, 3 is the electromagnet,
Reference numeral 5 designates a spring, 7 a cover, and 8 a support member, which have the same structure as in the prior art example described above, and therefore are given the same numbers as in the prior art example and their explanations will be omitted. 10 is a resin-molded stopper that has an O-ring guide on its periphery and is supported on the outer periphery of the print head, and 11 is an O-ring that presses the armature 1 into contact with the outer end of the electromagnet 3.

The operation of the print head having the configuration of the other conventional example described above is similar to that of the conventional example described above.

Problems to be Solved by the Invention However, in the conventional configuration, the stopper is a resin molded product, and its dimensional properties are affected by molding conditions.
There was a problem in that the thickness and elasticity of the portion in contact with the armature were not constant in the circumferential direction, which deteriorated printing quality.

This is because when multiple printing wires print at the same time, if the thickness and elasticity of the stopper 9 differs in the circumferential direction, the swing stroke will change, making the arrival time to the printing paper uneven, but the printing head Since printing is performed while moving on the printing paper, deviations in the arrival time of the printing wire cause the dots to shift, reducing printing quality.In addition, if the stroke is not uniform, the final speed of the printing wire changes, causing the printing pressure to change. This means that variations occur and print quality deteriorates.

Means for Solving the Problems The present invention is a printing device that uses a resin sheet as a stopper of an armature.

Effect According to the above configuration, since the flatness of the resin sheet is originally good, the swinging stroke is uniform, the time for the printing wire to reach the printing medium is uniform, and the strength at that time is uniform. Embodiment FIG. 1 is a sectional view of a print head in an embodiment of the present invention. 1 is an armature, 2 is a printing wire, 3 is an electromagnet, 5 is a spring, 6 is a presser spring, 7 is a cover, and 8 is a support member. These are the same structures as the conventional example, and are given the same numbers as the conventional example. The explanation will be omitted. Reference numeral 4 denotes a stopper made of a resin sheet, which is provided with a hole for positioning as shown in FIG. .

The operation of the print head configured as described above will be described below.

First, the armature 1, which was in pressure contact with the stopper 4 by the spring 5 in the initial state, is attracted by the electromagnet 3 being excited, and swings around the outer end of the electromagnet 3 as a fulcrum.
At the same time, the printing wire 2 welded to the movable end of the armature 1 operates to perform a printing operation.

Next, when the electromagnet 3 is energized, the armature 1 and the printing wire 2 are pushed back by the spring 5, and the stopper 9
It collides with the object and returns to its initial state.

In this embodiment, since a synthetic resin sheet is used for the stopper 4, the swinging stroke of the printing wire is uniform in the circumferential direction, and when multiple printing wires print simultaneously, the printing wire touches the printing paper. arrive at the same time. Therefore, no dot misalignment occurs due to differences in arrival time.

Also, because the stroke is uniform, the final speed of the printing wire is equal, and printing is performed with uniform printing pressure.

Effects of the Invention The present invention uses a resin sheet for the stopper to make the swinging stroke of the armature uniform in the circumferential direction, thereby realizing an excellent print head that can improve print quality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a print head according to an embodiment of the present invention, and FIG.
The figure is a plan view of a resin sheet stopper, Figure 3 is a sectional view showing an example of a conventional print head, Figure 4 is a plane view of a stopper that supports the inside of a molded product, and Figure 5 is a diagram of a conventional print head. A sectional view showing another example, and FIG. 6 is a plan view of a stopper for supporting the outside of the molded product. 1... Armature, 2... Printing wire, 3...
・Electromagnet, 4...Resin sheet stopper, 5...
・Spring, 6... Pressing spring, 7... Cover, 8...
・Supporting member, 9...Inner support stopper, 10...
・Outside support stopper, 11... Name of O-ring representative: F, Physician, Mi, Male, and 1 other person 1st
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] an armature arranged radially with its movable end facing inward and biased toward the return side; a printing wire disposed at each movable end of the armature; and selectively driving the armature to An electromagnet for causing the printing wire to perform impact printing on a recording medium, and an elastic member formed by punching out a synthetic resin sheet material into an annular shape and arranged at a position to abut the movable end of the armature when the armature returns. A print head characterized by: