JPH0530631B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to the structure of a wire dot type print head, and in particular to a wire dot type print head that has an improved coupling structure between a plurality of wires and an armature that extends and retracts the wires. Regarding the structure of

(Prior Art) Printing devices (printers) are used as input/output devices for electronic computers and various electronic devices, and various types of print heads are used in such printing devices. One of them is a wire dot type print head.

This wire dot type print head consists of multiple (e.g. 9 to 24) thin wires (e.g. 0.2 in diameter).
Characters such as letters and numbers, as well as images, are recorded on the recording paper by arranging tungsten wires (mm tungsten wires) in a line and controlling the protrusion (pressure contact) and retreat of each wire in synchronization with the lateral movement of the printing head. It is also one of the impact type printing heads. This type of wire dot type print head uses a plurality of electromagnets corresponding to the number of wires, an armature driven by each electromagnet, and a plurality of wires connected to the tip of each armature. By controlling the on/off of each electromagnet using a code signal and controlling the on/off position of each armature, the wires connected to their tips are made to protrude (pressure contact) and retreat from the recording paper. .

In this case, each wire is guided at several points along the way, but in order to reduce loss due to sliding resistance, the rear end of each wire should be brought as close to the center as possible to minimize warping. There is a need.

In the conventional wire dot type printing head, as shown in FIGS. 1 and 2, a hole 2 for passing the wire is formed at the tip of the armature 1, and the rear end of the wire 3 is inserted into this hole. After passing it through, it was joined by soldering 4 using silver solder or the like.

However, in such a conventional method of connecting a wire and an armature, since the hole 2 is formed at the tip of the armature 1, the width B of the tip of the armature must be a certain value or more, and cannot be made smaller. For this reason, when increasing the number of wires to make printing clearer, the tips of the armatures 1 interfere with each other, so the rear ends of the wires 3 cannot be arranged near the center and must be arranged far away from the center. You won't be able to use it. If the rear end of the wire 3 deviates from the center position, the wire will warp, resulting in an increase in sliding resistance at the guide portion, resulting in an increase in drive loss. For this reason, Figures 1 and 2
The bonding method shown in the figure has a problem in that it cannot meet the demand for an increase in the number of wires.

(Objective) The object of the present invention is to eliminate such conventional drawbacks, reduce the armature tip width, and
The object of the present invention is to provide a wire dot type printing head which can support the wire with sufficient strength even when the wire is fixed at this small tip.

(Description of Embodiment) FIGS. 3 to 6 are diagrams showing an embodiment of the wire dot type printing head according to the present invention, and the present invention will be specifically described below with reference to these drawings.

In FIG. 3, a boss member 7 made of plastic mold is arranged in a casing formed by joining the upper body 5 and lower body 6, and a side yoke 8A is integrally formed around this boss member by outsert molding. The boss member 7 is also engaged with the yoke 8. Inside the yoke 8 there is a core iron 9 and a coil 1 wound around it.
An armature 1A having a plunger 11 is attached to the lower side of the side yoke 8A. This armature 1A and the plunger 1 fixed to it
1 is a plurality of pieces (for example, 24 pieces) as shown in Figure 4.
The cores 9 are arranged radially in correspondence with each of the cores 9. The magnetic flux path of the electromagnet is formed by the core 9, yoke 8, side yoke 8A, and plunger 11, as indicated by φ in FIG.

A bag holder 13 is fixed in the lower body 6 by screws 12, and a stopper 14 is held in a recessed portion above the bag holder. Thus, each of the armatures 1A is positioned by a post 15 fixed to the lower side of the side yoke 8A and a hole 16 into which the plunger 11 is loosely fitted, and is positioned by the back holder 13 and the screw 12.
As a result, the lower surface of the side yoke 8a is pressed by the leaf springs 17 arranged at a plurality of positions in the circumferential direction, that is, corresponding to each armature 1A, and the vicinity of the tip thereof is returned and held by the spring 18 and the stopper 14, , held in place. Therefore, in a normal state, each armature 1A is in a lower non-operating position (retracted position) where it abuts against the stopper 14 by the return spring 18, as shown in FIG. 3, and the plunger 11 is attracted upward by the electromagnet. At this time, the tip of the spring 18 is displaced upward by a predetermined distance to reach the operating position.

A printed circuit board 20 is attached to the upper side of the yoke 8 via an aluminum spacer 19 for heat radiation. The electric circuit on the printed circuit board 20 and the coil 10 are connected via terminals 21 and 22.

As shown in Figure 4, there are multiple radially arranged
The proximal end (rear end) of a wire (for example, a tungsten wire with a diameter of 0.2 mm) 3 is connected to the distal end of each of the armatures 1A. The wire 3 passes through the inside of the boss member 7, and is further slidably guided by a plurality of guides 23, 24, 25, 26, and extends to the upper end (tip end of the print head) in FIG. are doing.

Therefore, by controlling the code signals introduced via the printed circuit board 20, a plurality of (for example, 24) code signals are transmitted.
By controlling the energization to each of the coils 10, the displacement of each armature 1A is controlled, and the width of the recording paper 27 is controlled while controlling the displacement (protruding or normal retracted position) of these wires 3. A predetermined character or image is recorded on the recording paper 27 in correlation with the control of the moving speed of the print head in the direction. This printing operation involves the stamping operation of each wire 3 and the on/off operation of energizing each coil 10, which generates noise and heat. By forming the aluminum spacer 19 and interposing the aluminum spacer 19, sound insulation and heat radiation effects are achieved.

A weight 29 made of lead or the like is held inside the lower body 6, that is, below the bag holder 13 in the illustrated example, with a disc spring 28 interposed therebetween, to absorb vibrations (especially Resonance phenomenon) is suppressed, and the movement of each armature 1A and each wire 3 coupled thereto is accurately controlled.

In Figures 4 to 6, each armature 1A
The tip of the wire is bent forward (in the direction of wire extension) at a substantially right angle to form a bent portion 30. The rear end of the wire 3 is brought into contact with the armature 1A while being engaged with the inner corner of the bent portion 30, and is connected to the armature 1A by soldering 31, such as silver soldering, as shown in FIG.

In this way, each wire 3 can be brazed to each armature 1A over a relatively long range including the bent portion 30, thereby increasing the bonding strength.
Furthermore, since there is no need to provide a conventional hole (hole 2 in FIG. 1) at the tip of each armature 1A, the width b of the tip of each armature 1A is determined by the diameter of the wire 3 (for example, as shown in FIG. 5). The value can be as small as 0.2mm).

The plurality of wires 3 are arranged in a line along the upper and lower diameter in FIG. They cannot be arranged in the same manner as in Figure 4, but must be arranged in an arc or an ellipse as shown in Fig. 4. In this case, the maximum deviation shown by D in FIG. 4 occurs between the rear end and the tip of the wire. This maximum deviation D is required to be as small as possible in order to reduce loss due to wire sliding resistance.

By the way, in the wire dot type printing head of the present invention, as shown in FIGS. 4 to 6, the width of the tip end of the armature 1A can be made much smaller than the conventional one, so even if the number of wires is increased, The maximum deviation D is not so large compared to the structure of Improved clarity or reduced loss can be achieved.

(Effects) As is clear from the above explanation, in the wire dot type printing head for printing by making the wire connected to the tip of the armature protrude and press it against the recording material, the armature is connected to the wire. It has a flat plate part extending in a direction intersecting the longitudinal direction, and a bent part bent at a distal end of the flat plate part at a substantially right angle to the longitudinal direction of the wire, and the rear end surface of the wire and the flat plate part are in contact with each other, and the wire side surface continuous from the rear end surface is in contact with the bent part, and the wire is fixed to the flat plate part and the bent part of the armature. The force in the longitudinal direction is received by the plane of the flat plate portion of the armature, and the wire can be directly pushed out in the longitudinal direction. Furthermore, since the wire side surface portion and the bent portion are in contact with each other, stress concentration on the wire attachment portion during printing can be avoided. In this way, it is possible to obtain the effect that the recording state when the armature is in contact can be stabilized.

[Brief explanation of the drawing]

1 and 2 are a plan view and a vertical sectional view illustrating the joint portion between the armature and the wire in a conventional wire dot type print head, and FIG. 3 shows the overall structure of an embodiment of the wire dot type print head according to the present invention. FIG. 4 is an explanatory diagram showing the arrangement of a plurality of armatures in the print head shown in FIG. 3, and FIGS. 5 and 6 show each armature and each wire in the print head shown in FIG. FIG. 1, 1A... Armature, 3... Wire, 5, 6
...Body (casing), 8...Yoke, 8A...Side yoke, 9...Core, 10...Coil, 11...Plunger, 14...Stopper, 15...Post, 17
...Plate spring, 18...Return spring, 20...Printed circuit board, 23-26...Wire guide, 27...Recording paper, 30...Bending portion, 31...Brazing.

Claims (1)

[Scope of Claims] 1. A wire dot type printing head for printing by making a wire connected to a tip of an armature protrude and press it against a recording material, wherein the armature intersects with the longitudinal direction of the wire. a flat plate portion extending in the direction; and a bent portion bent at a distal end of the flat plate portion at a substantially right angle to the longitudinal direction of the wire, and the rear end surface of the wire abuts the flat plate portion, and , a wire dot type printing characterized in that the wire side surface continuous from the rear end surface and the bending part are in contact with each other, and the wire is fixed to the flat plate part and the bending part of the armature. Head. 2. The wire dot type print head according to claim 1, wherein the bent portion has a width approximately equal to the diameter of the wire.