JPH05220982A - Main guide positioning mechanism of printing head - Google Patents

Abstract

PURPOSE:To enhance the positioning accuracy of a main guide in order to prevent the lowering of printing grade due to the bad positional accuracy of the main guide of a dot impact printing head. CONSTITUTION:The abutting surface of the flange part 1a of a main guide 1 and the seat part 2c of a head frame 2 is formed as an inclined surface and the outer shape part 1a is supported by two surfaces of the square hole of the head frame 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head positioning mechanism, and more particularly to a structure for determining the position of a main guide by inclining a contact portion between a main guide and a head frame.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a main guide positioning structure of this type is constructed by fitting a square main guide 1 having a flange in a square hole portion of a head frame 2 from the inside of the head frame. The guide 1 is pressed by the spring 3.

Position accuracy has been achieved by strictly controlling the dimensional accuracy of the outer diameter of the main guide 1 and the square hole of the head frame 2.

[0004]

In the conventional main guide positioning method, there is some looseness in the fit between the square hole of the head frame and the outer diameter of the main guide. There was a problem to exert.

Further, it is necessary to strictly control the size of the fitting portion between the main guide and the head frame.

It is an object of the present invention to provide a main guide positioning mechanism for a print head, which absorbs play caused by the fit between the head frame and the main guide and improves the positioning accuracy.

[0007]

In order to achieve the above object, a main guide positioning mechanism of a print head according to the present invention fits a main guide for guiding a print wire of a print head for a dot impact printer and a main guide. A main frame positioning mechanism for a print head, which has a head frame having a hole for the main frame, and a flange of the main frame is elastically contacted by a spring with a seat of an end surface of the hole of the head frame to position and support the main frame on the head frame. And, the abutting surface of the flange portion of the main guide and the seat portion of the head frame is formed as an inclined surface,
The inclined surfaces of the flange portion and the seat portion are butted against each other.

[0008]

The abutting surface between the head frame and the main guide is an inclined surface, and the main guide is supported on the head frame by two surfaces to position the main guide.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A is a sectional view showing a print head according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along the line AA of FIG. 1A. 2 is a perspective view showing the tip of the main guide used in FIG. 1, and FIG. 3 is a perspective view showing the tip of the head frame used in FIG.

In the figure, the main guide 1 has a reference surface D at the most distal end and a rectangular flange portion 1a at a position retracted from the reference surface D.

Guide holes 1b for guiding the print wires 4 are formed in the reference plane D of the main guide 1 by the same number as the print wires 4.

The flange portion 1a of the main guide 1 is not parallel to the reference plane D, but has an inclined surface such that one point A of one corner and three corners is high and its diagonal point B is low.

On the other hand, the head frame 2 has at its tip end a square hole 2a into which the reference surface D of the main guide 1 is fitted,
A structure is provided in which a square hole 2b into which the main body of the main guide 1 is fitted is provided, and a flange portion 1a of the main guide 1 abuts on a seat portion 2c formed at an end surface of a step between the square hole 2a and the square hole 2b. Is becoming

The seat portion 2c provided on the end face of the square hole of the head frame 2 is attached to the flange portion 1a of the main guide 1 so that the wire guide hole 1b of the main guide 1 is perpendicular to the tip face of the head frame 2. It is formed as an inclined surface having an inclination angle that follows the provided inclined surface 1c.

The main guide 1 is fitted in the square hole 2b from the inside of the head frame 2, and an intermediate guide 5, an intermediate guide 6, an intermediate guide 7, and an intermediate guide 8 are attached in that order to the rear side thereof.

The intermediate guides 4 to 8 are coil springs 3
Are supported by pressing the intermediate guide 8 toward the main guide 1.

The flange portion 1a of the main guide 1 is brought into close contact with the seat portion 2c of the head frame 2 when the coil spring 3 pushes the intermediate guide 8. This closely contacted surface is inclined by θ ₁ and θ ₂ with respect to the acting direction of the force of spring 3.
Because it is only inclined, component force is generated. FIG. 4 is a diagram modeling this. Due to the force F of the spring 3 acting on the inclination of θ ₁ , component forces Fθ ₁₁ and Fθ ₁₂ are generated. A component force is similarly generated with respect to the inclination of θ ₂ , so that the main guide 1 moves in the directions of the surfaces E and F.

As a result, the surfaces E and F of the main guide 1 are
Is in close contact with the surfaces e and f of the head frame 2 and allows the position of the main guide 1 to be determined.

[0019]

As described above, according to the present invention, the main guide having the inclined flange portion, the head frame in which the surface contacting the flange portion is inclined, and the spring for pressing the main guide against the head frame are provided. By having the structure having the main guide, the main guide is always contacted with and supported by the two surfaces of the square hole portion of the head frame,
The position accuracy of the main guide is improved and the printing quality is improved.

Further, in the dimensional control, the two surfaces of the head frame square hole portion which is the above-mentioned contact portion and the two portions of the main guide.
Since it is only necessary to manage the surface, the cost of parts is reduced.

[Brief description of drawings]

1A is a cross-sectional view showing a print head according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA of FIG.

FIG. 2 is a perspective view showing a main guide used in the present invention.

FIG. 3 is a perspective view showing a head frame used in the present invention.

FIG. 4 is a model diagram of the present invention.

FIG. 5A is a sectional view showing a conventional print head.
(B) is a BB line sectional view of (a).

[Explanation of symbols]

 1 Main guide 1a Main guide flange 2 Head frame 2c Head frame seat 3 Spring 4 Print wire

Claims (1)

[Claims] 1. A main frame for guiding a print wire of a print head for a dot impact printer, and a head frame having a hole for fitting the main frame,
A main guide positioning mechanism of a print head that elastically contacts a flange portion of a main guide with a seat portion of a hole end surface of a head frame by a spring to position and support the main guide, the flange portion of the main guide and the head frame. A main guide positioning mechanism for a print head, characterized in that the abutting surface with the seat portion is formed as an inclined surface, and the inclined surfaces of the flange portion and the seat portion are abutted with each other.