JPH0111468Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dot printing head equipped with a wire guide body for guiding the tips of a plurality of printing wires in a single vertical line.

FIG. 1 is a sectional view showing this type of dot printing head. In the figure, 1 is a plurality of printing wires at the tips of which print dots on a printing surface (not shown), and 2 is a wire guide body. In the center thereof, guide holes 3 are provided for guiding the tips of the printing wires 1 in a vertical line at predetermined intervals. 4 is an armature to which the base end of the printing wire 1 is attached, 5 is a leaf spring that supports each armature 4 at its free end, and 6 is a plurality of grooves formed radially in the center so as to correspond to each armature 4. It has a circular front yoke.

7 is a disk-shaped base plate made of a magnetic material, 8 is an annular permanent magnet fixed on the base plate 7, 9 is an annular rear yoke fixed on the permanent magnet 8, and 10 is each armature 4. A plurality of electromagnetic cores 11 are provided on the base plate 7 so as to correspond to the above, and 11 is an electromagnetic coil attached to the outer periphery of each core 10. The base portions of the springs 5 are stacked on top of each other, and the front yoke 6 and wire guide body 2 are stacked on top of each other in this order, and these are assembled together with screws.

In this configuration, the magnetic flux of the permanent magnet 8 passes through a magnetic path consisting of the rear yoke 9, the front yoke 6, the armature 4, the core 10, and the base plate 7, and this magnetic flux causes the armature 4 to move toward the core 10 during printing pauses.
is attracted to the end of the leaf spring 5, thereby causing the leaf spring 5 to be bent as shown.

When the coil 11 is energized during printing, a magnetic flux is generated that cancels the magnetic flux of the permanent magnet 8, and the armature 4 is released from the core 10. As a result, the printing wire 1 is moved by the restoring force of the leaf spring 5. It is driven and prints with its tip.

By the way, in the above-mentioned dot printing head, each electromagnet consisting of a core 10 and a coil 11,
The base end portions of the printing wires 1 attached to the corresponding armatures 4 are approximately elliptical in order to align the tip ends of the printing wires 1 in a vertical line through the guide holes 3 of the wire guide body 2. Therefore, when viewed from the front (printing surface side) of the dot printing head, the arrangement from the base end to the tip of each printing wire 1 is as shown in FIG.

Therefore, for example, the insertion angle of the wire guide body 2 into the guide hole 3 is different between the central printing wire 1 and the end printing wire 1 shown in FIG.
As shown in Fig. 3, the diameter of each guide hole 3 is unified to the minimum diameter that allows the printing wire 1, which is inserted at the largest inclination angle, to operate smoothly. In other printing wires 1, as shown in FIG. 4, a gap is created between the wire and the inner wall of the guide hole 3, making it impossible to determine the position of the tip of the wire, resulting in poor printing, etc. This has the disadvantage that the printing quality deteriorates due to the occurrence of the gap, and furthermore, the impact force applied to the wire guide body 2 during printing increases due to the above-mentioned gap, resulting in a shortened lifespan of the wire guide body 2. It was hot.

The purpose of the present invention is to solve these drawbacks, and by changing the diameter of each guide hole according to the insertion angle of each dot wire into each guide hole of the wire guide body, the gap between the dot wire and the guide hole can be reduced. It is characterized by being made smaller.

One embodiment of the present invention will be described below. First, if the diameter of the guide hole 3 provided in the wire guide body 2 is D, this diameter D is the diameter of the printing wire 1 as shown in FIG. The thickness of the guide body 2 is L,
The insertion inclination angle of the tip of the printing wire 1 with respect to the center line of the guide hole 3 is θ, and the reciprocating direction of each printing wire 1 with respect to the vertical center line of the wire arrangement surface of the wire guide body 2 as shown in FIG. When the angle is α, D=Ltanβ+d, where tanβ=tanθ・sinα.

Therefore, based on the above formula, the material of the wire guide body 2 is adjusted so that the diameter of each guide hole 3 provided in the wire guide body 2 is minimized according to the insertion angle of each inserted printing wire 1. , wear, etc. can be taken into consideration.

FIG. 5 is an enlarged sectional view of the main part of the wire guide body 2 in which the diameter of each guide hole 3 is set in this way. By narrowing the gap with the inner wall of the hole 3, the position of each printing wire 1 on the guide body 2 can be more strictly regulated. This wire guide body 2 can be manufactured by plastic molding or the like.

In the present invention, other structures are the same as those shown in FIG. 1, so their explanation will be omitted.

As explained above, in the present invention, by changing the diameter of each guide hole according to the insertion angle of each printing wire, guiding can be performed by reducing the gap between the two. The position of the printing wire can be kept constant, and when printing is thereby performed, the effect of improving the printing quality can be obtained.

In addition, as mentioned above, since the gap between each printing wire and the inner wall of the guide hole can be reduced, the impact force applied to the wire guide body during printing is reduced, and as a result, the life of the wire guide body can be extended. It can also be used in various impact type dot printing heads that print dots by driving a plurality of printing wires.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an example of a dot printing head to which the present invention is applied, and FIG. 2 is a front view showing the arrangement of printing wires from the base end to the tip end in the dot print head of FIG. 1. 3 and 4 are partially enlarged sectional views for explaining the insertion angle of the printing wire into the guide hole, and FIG. 5 is an enlarged sectional view of the main part of a wire guide body showing an embodiment of the present invention. 1... Printing wire, 2... Wire guide body, 3
... Guide hole, 4 ... Armature, 5 ... Leaf spring, 8 ... Permanent magnet, 10 ... Core, 11 ... Coil.

Claims (1)

[Scope of utility model registration request] In a dot printing head that is equipped with a wire guide body having guide holes for guiding the tips of a plurality of printing wires in a line, and prints dots by driving each of the printing wires with an electromagnet, each of the wire guide bodies A dot printing head characterized in that the diameter of the guide hole is set to be the minimum according to the insertion angle of each printing wire inserted into the guide hole.