JPH0732616A - Dot impact type printing head apparatus - Google Patents

Abstract

PURPOSE:To provide a dot impact type printing head apparatus capable of maintaining good printing quality even in the case where a difference in wire strokes exists. CONSTITUTION:A dot impact type printing head apparatus is provided with an armature 4 having a printing wire 1, a leaf spring 5 supporting this armature 4 reciprocably along the printing wire 1, a magnetic circuit having a U-shaped yoke 10 and a permanent magnet 9 for attracting the armature 4 against a return force of the leaf spring 5, a base plate 8 supporting the leaf spring 5, and a drive coil 12 for controlling to repeatedly deenergize a line of a magnetic force of the permanent magnet 9 at a predetermined speed. Further, a spacer 7A is provided between the leaf spring 5 and the base plate 8, and an auxiliary leaf spring 7 is provided between the spacer 7A and the base plate 8. The auxiliary leaf spring 7 and the armature 4 are interconnected together by a pin-like member 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot impact type print head device, and more particularly to a dot impact type print head device provided with a print wire and a leaf spring which is reciprocally supported along the print wire.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional example. The conventional example shown in FIG. 4 includes an armature 54 having a print wire 51,
A magnetic circuit including a leaf spring 55 that reciprocally supports the armature 54 along the print wire 51, a U-shaped yoke that attracts the armature 54 against the restoring force of the leaf spring 55, and a permanent magnet 59. A base plate 58 that supports the leaf spring 55 and a drive coil 62 that repeatedly demagnetizes the magnetic force lines of the permanent magnet 59 at a predetermined speed are provided.

Here, reference numeral 61 indicates a yoke core, reference numeral 63 indicates a substrate equipped with an energization control circuit for the drive coil 62, reference numeral 52 indicates a guide portion for assisting the operation of the print wire 51, and reference numeral 53 indicates. An arm mounted between the print wire 51 and the armature 54 is shown. Reference numeral 56 indicates a cross pin that maintains the normal operation of the leaf spring 55, and reference numeral 58 indicates a base plate that fixes one end of the cross pin 56.

First, when the drive coil 62 is not energized, the armature 54 is attracted to the yoke core 61 by the magnetic force of the permanent magnet 59. At this time, the leaf spring 55 and the cross pin 56 are bent and strain energy is stored. When the drive coil 62 is energized, the magnetic flux flowing in the yoke core 61 is demagnetized, and the armature 5
The force of attracting 4 to the yoke core 61 is reduced. Therefore, the strain energy stored in the leaf spring 55 and the cross pin 56 is dissipated, and the print wire 51 is driven in the direction of the symbol a in FIG. 4 via the arm 53 and the armature 54.

At this time, the printing wire 51 makes a striking motion with respect to the paper surface on the platen through the ink ribbon to perform printing. After printing, when the coil 62 is de-energized again, the armature 54 is attracted to the yoke core 61 again and returns to the initial state. In actual printing, this series of operations is repeated at high speed.

Now, the movement of the cross pin 6 will be described. Without the cross pin 56, when the printing wire 51 strikes the paper surface on the platen via the ribbon during the printing operation, the inertial force of the armature 54 causes the armature printing operation including the printing wire 51 and the arm 53. A movement centering around the center of the rotational movement required for
The leaf spring 55 is flexed in addition to the flexure necessary for the printing operation. This hinders the series of printing operations described above. The cross pin 56 is intended to always keep the armature system motion in the rotary motion necessary for the printing operation during the striking motion to enable a higher speed motion.

[0007]

In the conventional print head described above, the drive coil 62 is energized to start the armature system including the print wire 51 and the arm 53, and then the coil 62 is de-energized. The time required to return to the original position (return time) is the print wire 51
It changes when the operating distance (wire stroke) changes.
Therefore, when the armature system performs continuous motion, the influence of the inertial force of the previous operation on the next operation depends on the size of the wire stroke, and when the wire stroke is large or small (such as due to the curvature of the platen), There is an inconvenience that there is a difference in printing quality between a portion having a large wire stroke and a portion having a small wire stroke.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dot impact type print head device which can improve the disadvantages of the prior art and can maintain good print quality even when there is a difference in wire stroke. To aim.

[0009]

According to the present invention, an armature provided with a printing wire, a leaf spring supporting the armature reciprocally along the printing wire, and the armature against the restoring force of the leaf spring. The magnetic circuit includes a U-shaped yoke for attraction and a permanent magnet, a base plate for supporting the leaf spring, and a drive coil for repeatedly degaussing magnetic lines of force of the permanent magnet at a predetermined speed. Further, a spacer is provided between the leaf spring and the base plate, an auxiliary leaf spring is provided between the spacer and the base plate, and the auxiliary leaf spring and the armature are connected by a pin-shaped member. ing. This aims to achieve the above-mentioned object.

[0010]

[Operation] The rotating end of the auxiliary leaf spring 7 is the base plate 8
The cross pin 6 does not affect the operation of the armature 4 when printing is performed in a range (a small wire stroke) that does not contact the armature 4. Therefore, the printing operation is performed when the cross pin 6 is not used. Further, when printing is performed in a range in which the rotating end of the auxiliary leaf spring 7 contacts the base plate 8 (large wire stroke), the cross pin 6 suppresses the operation of the armature 4. Therefore, the armature 4 operates when the cross pin 6 is used, and the return time is faster than when the cross pin 6 is not used. As a result, the difference in return time between the case where the wire stroke is small and the case where the wire stroke is large becomes small, and the adverse effect of the difference in the wire stroke on the print quality can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment shown in FIGS. 1 to 3, an armature 4 having a print wire 1, a leaf spring 5 supporting the armature 4 so as to reciprocate along the print wire 1, and a return of the armature 4 to the leaf spring 5. A magnetic circuit including a U-shaped yoke 10 and a permanent magnet 9 that attract against a force, a base plate 8 that supports the leaf spring 5, and a drive coil that repeatedly degausses magnetic lines of force of the permanent magnet 9 at a predetermined speed. 12 and 12.

A spacer 7A is provided between the leaf spring 5 and the base plate 8, and an auxiliary leaf spring 7 is provided between the spacer 7A and the base plate 8.
The auxiliary leaf spring 7 and the armature 4 are connected by a cross pin 6.

To explain this in more detail, in FIG.
Armature 4 with print wire 1 and arm 3
Are fixed and supported at one end of the leaf spring 5. The other end of the leaf spring 5 is fixed to one end surface of the U-shaped yoke 10. Further, the leaf spring 5 is bent in the direction of rotating the armature 4 in the direction of symbol a in FIG. 1, that is, in the direction opposite to the direction of symbol a in FIG.

Further, a cross pin 6 for suppressing the printing operation (rotational motion) of the armature 4 is attached to the armature 4, and the side opposite to the attachment side of the cross pin to the armature 4 is the above-mentioned auxiliary plate. It is attached to the spring 7.

Further, the space plate 8 is attached as a stopper portion so that the movement of the auxiliary leaf spring 7 is not suppressed when the wire stroke is small, and is suppressed when the wire stroke is large. The space plate 8 functions so as not to move the armature 4 in the direction of rotating the armature 4 in the direction a in FIG. 1 when the movement of the auxiliary leaf spring 7 exceeds a certain value of the wire stroke.
The other mechanism is set to be the same as that of the conventional technique.

Next, the operation will be described.

3 (A) and 3 (B) are partial cross-sectional views of the print head showing the operations performed during printing. First, when the coil 12 is not energized, the magnetic force of the permanent magnet 9 causes the armature 4 to move to the yoke core 11
Is adsorbed on the surface of. At this time, the leaf spring 5 connected to the armature 4 and the auxiliary leaf spring 7 connected to the armature 4 via the cross pin 6 are bent and strain energy is stored. At this time, since the print wire 1 is interlocked with the armature 4 via the arm 3, it is housed inside the print head.

Next, when the coil 12 is energized through the substrate 13, the magnetic flux flowing in the yoke core 11 is demagnetized, the magnetic attraction force acting on the armature 4 is reduced, and the leaf spring 5 and the auxiliary leaf spring 7 are The stored strain energy is released. Therefore, the armature 4 rotates in the direction of the symbol a in FIG. At this time, the print wire 1 is connected to the arm 3
Since it is interlocked with the armature 4 via the
It operates in the direction of the reference sign b, and strikes the paper surface through the ribbon to print dots. When the power is cut off again,
Since the magnetic flux flows through the yoke core 11 again, the armature 4 is attracted to the yoke core 11 and pulled back to its original position. In actual printing, this series of operations is repeated at high speed.

Next, the operation of the auxiliary leaf spring 7 will be described. First, the rotating end of the auxiliary leaf spring 7 is
The cross pin 6 does not affect the operation of the armature 4 when printing is performed in a range (a small wire stroke) that does not contact the armature 4. Therefore, the printing operation is performed when the cross pin 6 is not used. Further, when printing is performed in a range in which the rotating end of the auxiliary leaf spring 7 contacts the base plate 8 (large wire stroke), the cross pin 6 suppresses the operation of the armature 4.

Therefore, the armature 4 operates when the cross pin 6 is used, and the return time is faster than when the cross pin 6 is not used. From this, when the wire stroke is small and the wire stroke is large,
The difference in return time is reduced, and the adverse effect of different wire strokes on print quality can be reduced.

FIG. 2 shows the operation of the tip of the printing wire 1 described above. In the figure, the horizontal axis represents time and the vertical axis represents the operation (wire stroke) of the tip of the printing wire 1. It can be seen that the difference (Δt in FIG. 4) between the return times of the print wire when the wire stroke is large and when the wire stroke is small is smaller than that in the conventional example shown in FIG.

[0022]

As described above, according to the present invention,
By attaching the cross pin to the auxiliary leaf spring, the difference in the operation of the print head due to the difference in wire stroke can be reduced, and the difference in the print quality due to the difference in wire stroke can be reduced. A print head device can be provided.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a displacement waveform at the tip of the printing wire in FIG.

3A and 3B are explanatory views showing the operation of FIG. 1, in which FIG. 3A shows a case where the wire stroke is small, and FIG. 3B shows a case where the wire stroke is large.

FIG. 4 is an explanatory diagram showing a conventional example.

5 is a diagram showing the operation of FIG. 4. FIG.

FIG. 4 is a diagram showing a displacement waveform at the tip of the printing wire in FIG.

[Explanation of symbols]

 1 printing wire 4 armature 5 leaf spring 6 cross pin 7 auxiliary leaf spring 7A spacer 8 base plate 9 permanent magnet 10 U-shaped yoke 12 drive coil

[Procedure amendment]

[Submission date] May 24, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

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

FIG. 2 is a diagram showing a displacement waveform at the tip of the printing wire in FIG.

3A and 3B are explanatory views showing the operation of FIG. 1, in which FIG. 3A shows a case where the wire stroke is small, and FIG. 3B shows a case where the wire stroke is large.

FIG. 4 is an explanatory diagram showing a conventional example.

5 shows a displacement waveform at the tip of the printing wire in FIG .
It is a diagram .

[Explanation of symbols] 1 printing wire 4 armature 5 leaf spring 6 cross pin 7 auxiliary leaf spring 7A spacer 8 base plate 9 permanent magnet 10 U-shaped yoke 12 drive coil

Claims (2)

[Claims] 1. An armature provided with a printing wire, a leaf spring that reciprocally supports the armature along the printing wire, and a U-shaped yoke that attracts the armature against the restoring force of the leaf spring. A dot impact type print head device comprising: a magnetic circuit having a permanent magnet; a base plate supporting the leaf spring; and a drive coil for repeatedly controlling demagnetization of magnetic lines of force of the permanent magnet at a predetermined speed. A dot impact type characterized in that a spacer is provided between the spring and the base plate, an auxiliary leaf spring is provided between the spacer and the base plate, and the auxiliary leaf spring and the armature are connected by a cross pin. Print head device. 2. The dot impact type print head device according to claim 1, wherein the base plate and the armature are incorporated in a part of the magnetic circuit.