JPH0737139B2 - Print head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a print head used in a dot matrix printer.

[Conventional technology]

In a printing apparatus that prints characters and figures using a print wire, many small-sized and lightweight multi-core print heads capable of graphic processing have been developed due to the recent boom in personal computers and OA. Due to market demands, higher density, smaller size, higher speed and lower price are required. Conventionally, most of the print heads used in this type of printing device have an electromagnet as a basic driving means for the print wire. Among them, the print wire is fixed directly to the armature and several print wires are attached. In most of the cases, the wire tips were aligned on a straight line or a plurality of straight lines by being guided by a guide plate.

[Problems to be solved by the invention]

The above-mentioned conventional print head uses the print wire by bending it in order to align the wire at a predetermined position.
The wire is damaged during printing, and it is necessary to lengthen the wire in order to prevent the wire from being damaged, which is a drawback that the printing speed cannot be increased. Alternatively, there is a drawback in that the position of the guide hole is not in a straight line because the print wire is bent and used, and it takes a lot of trouble to pass the print wire through the guide hole.

On the other hand, when trying to use the wire as it is, it is necessary to guide the wire diagonally with the guide plate, but there are drawbacks that it is difficult to process the hole diagonally and it becomes expensive. Due to the operation, there is a drawback that the printing position is displaced on the printing surface even if the wires are aligned at a predetermined position on the wire guide.

[Means for solving problems]

The print head of the present invention includes a print wire, an armature joined to the tip of the print wire so that the print wire obliquely abuts the print surface, and the armature is rotated about one end of the armature to rotate the print wire in the axial direction. A holding part that holds the armature so that the armature can be moved to a position and a guide that has a guide hole that holds the printing wire in a straight line, and a straight line from the rotation center of the armature to the joining point between the armature and the printing wire Intersects the central axis of at a right angle.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a half sectional view showing an embodiment of a print head according to the present invention. The armature 1 rotates clockwise around the fulcrum 1a by the magnetic attraction generated by the coil 3 and the yoke 2, and hits the printing surface 11 with the printing wire 4 attached to the tip to print, and then the return spring.
It returns to the original position by the force of 10.

Here, the printing wire 4 is guided by the intermediate guide 5, the intermediate guide 6 and the tip guide 7 to a predetermined position, but as shown in FIG. 2, the holes 5a, 6a, 7a of each guide are aligned. It is arranged. 3 is a diagram showing the wire tip position of the tip of the print head shown in FIG. 1 as viewed from the printing surface 11 side.
The tip of the mark is at the position of 4S indicated by a black circle when at rest, and at the time of printing, that is, at the position of 11a shown in FIG. 2, it is at the position of 4M indicated by a white circle in FIG. It is configured.

On the other hand, a straight line connecting the armature fulcrum 1a and the wire attachment part 1b
1l and the center line 4l of the wire are configured to intersect at a right angle.

FIG. 4 is a perspective view showing the structure of the tip guide 7. The outer guide plate 7y has a tapered elliptical hole that becomes smaller toward the tip, and the number of wires is inside the hole. Are formed with a plurality of semicircular grooves 7d. The inner guide plate 7x has a semicircular groove 7c corresponding to the semicircular groove 7d of the outer guide plate 7y, and has a tapered projection that becomes smaller toward the tip. Here, by inserting the inner guide plate 7x into the outer guide plate 7y from the direction of arrow A,
A tip guide 7 for obliquely guiding the print wire 4 as shown in the figure is formed. Here, in the present invention, the outer guide 7y of the tip guide 7 is formed integrally with the frame 8 as shown in FIG.

〔The invention's effect〕

As described above, the present invention makes it possible to reduce the stress applied to the printing wire by setting the angle formed by the wire and the straight line connecting the armature fulcrum and the wire fixing point at a right angle, and as a result, the wire breakage or the like can be prevented. In addition to being able to prevent it, the printing wire can be shortened, and high-speed printing can be achieved. Further, since the guide holes are arranged in a straight line, the print wire can be easily inserted into the guide hole, and an inexpensive print head can be provided.

[Brief description of drawings]

FIG. 1 is a half sectional view of the print head of the present invention, and FIG.
FIG. 3 is a detailed view of an operating portion and a guide portion in the figure, FIG. 3 is a layout explanatory view of a wire tip of the print head of FIG. 1, and FIG. 1 ... Armature, 2 ... Yoke, 3 ... Coil, 4
...... Printing wire, 5 ... Mid guide, 6 ... Mid guide, 7 ... Tip guide, 8 ... Frame, 9 ... Hold spring, 10 ... Return spring, 11 ... Print surface.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41J 2/275 B41J 3/10 115 109

Claims (1)

[Claims] 1. In a print head of a dot matrix printer, a print wire, an armature joined at its tip so that the print wire obliquely abuts a print surface, and the armature with one end of the armature as a rotation center. The armature includes a holding portion that holds the armature so that the printing wire can rotate and move the printing wire in the axial direction thereof, and a guide having a guide hole that holds the printing wire in a straight line, and the armature from the rotation center of the armature. Print head in which a straight line to the junction between the print wire and the print wire intersects with the central axis of the print wire at a right angle