JPS63183857A - Impact dot head - Google Patents

Abstract

PURPOSE:To manufacture an impact dot head which shows almost no density variation between printing dots and also superior printing quality by laminating a core block, yoke, side yoke and back keep plate, each abutting with each other with respect to a nose and enabling the back keep plate to be pressed in a nose tip direction with the help of a leaf spring whose position of the external periphery is restricted. CONSTITUTION:In the screw tightening part of a stepped screw 23, the size of a stepped part of the stepped screw is set so that a gap may generate between a back keep plate 18 and a leaf spring 25 as well as between noses 14. In addition, the back keep plate 18 is laminated on a side yoke 10a which is laminated on a yoke 9a. The leaf spring 25 is formed with an metallic elastomer in contact with the back keep plate 18 in the center. Further the leaf spring 25 has an end which extends from the center to the external periphery and makes contact with the stepped screw 23 at the external edge of three legs having a spring property in a thickness direction. The position of the end is determined by means of the stepped screw 23, so that the end presses the back keep plate in the center. After this, laminated core blocks 5, 5a, yokes 9, 9a, fulcrum shafts 12, 12a and a keep plate 16 are held between a protrusion 3 of the nose 14 and the back keep plate 18 in such a way that no gap generates.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a connection between the nose and back presser plate of an impact dot head.

[Conventional technology]

In conventional impact dot heads, parts such as a wire guide member, coil block, yoke part, and armature to which a printed wire is fixed are sequentially assembled into the nose part, and finally the presser member is fixed to the nose part with screws.

Alternatively, there is a method of assembling the above-mentioned parts into one block in advance by tightening screws, etc., and fixing this block to the nose part, but the method of fixing these parts by tightening screws has the following disadvantages. Was.

[Problem that the invention seeks to solve]

In other words, since the parts are fixed together by the fixing force of the screws, if the screw tightening torque is too large, the parts will deform and the gap between the armature and the magnetic core will change. The problem arises that the print wire is incorrectly positioned at 6'S. Conversely, if the screw tightening torque is too weak or the dimensions of the parts vary, looseness may occur between the parts. In such a case, good printing quality cannot be expected, and malfunctions may also occur.

The present invention is intended to solve such problems, and its purpose is to secure the axial position of these parts with a simple structure, which causes play between the parts, and to provide excellent printing quality. The aim is to provide an impact dot head with high reliability.

[Means for solving problems]

The impact dot head according to the present invention is an impact dot head that attracts a clapper using electromagnetic force and performs printing by the striking force of the tip of a wire fixed to the clapper, and includes a nose having a fixed portion formed at the outer end thereof, and a nose having a fixed portion formed at the outer end thereof. a core block that comes into contact with the core block, a yoke that comes into contact with the core block, a site yoke that comes into contact with the yoke, a back presser plate that comes into contact with the side yoke, and an outer circumferential portion that is positionally regulated relative to the fixed portion. It is characterized by having a plate spring that presses the back presser in the nose direction.

(Example) Hereinafter, details of the present invention will be explained based on illustrated examples.

FIG. 1 shows an embodiment of the present invention, in which frame 1
has a wire nose 2 integrally molded at its tip, and this wire nose 2 engages with the wire guide 20 and is fixed to the nose 14, and the inner surface of the nose 14 has a shallow bottomed circular M-bar made of a magnetic material positioned on the protrusion. A core block 5 is integrally fixed.

Further, the nose 14 has a cylindrical hollow part that accommodates a magnetic circuit described below, and has cooling fins 14a for heat radiation on the outside of the outer wall of this hollow part, and has cooling fins 14a made of aluminum or aluminum alloy. It is made of metal and is integrally formed.
The outer end has a fixing part 14b formed with a female thread.

The core block 5 forms an electromagnet with a yoke 9 of a bottomed circle f:1 and a side yoke 10 of a disc bar, which will be described later, and attracts a drive lever 11, which will be described later, and has a circumferential surface on its inner surface. A core 7 around which a coil 6 is wound is formed protruding from a concentric circle corresponding to the number of wires. Further, on the end face of the cylindrical part 5a that defines the outer periphery of the core block 5, a cylindrical part 811 of an a-bottom cylindrical lower yoke 8 made of a magnetic material is positioned on the outer peripheral surface of the cylindrical part 4 provided inside the frame 1. 'J side comes into contact.

In this manner, the yoke 9 is axially positioned relative to the core block 5 on which the core 7 is formed, and forms part of a magnetic path.

31.31a is a flexible circuit board having wiring for supplying drive current to the coil 6.6a.

Reference numeral 10 denotes a disc-shaped side yoke made of a magnetic material, which is also positioned by the cylindrical portion 4 of the frame 1 and laminated on the yoke 9. On the plate surface of the side yoke 10 and the plate surface of the yoke 0, A radially oblique slit in which the drive lever 11 can swing is formed, and this slit allows the drive lever 11 to swing.
The fulcrum shaft 12, which serves as a swing fulcrum, is held.

By the way, the drive lever 11 described above is located at the fulcrum +11112
By swinging about the fulcrum, the print wire 13 fixed at the tip is brought into contact with the print paper via an ink ribbon (not shown). The fulcrum shaft 12 has both ends disposed within a groove formed in the side yoke 10, and its axial position is regulated by the yoke 9 and the side yoke 10.

Furthermore, this drive lever 11 is always connected to the tube V of the frame 1.
A return spring 15 interposed between the portion 4 and the drive lever 11
It is assembled so that it is biased toward the left in FIG. 1 and held at the standby position.

The core block 5a is positioned by the protrusion 17 on the presser plate 16, the bottomed cylindrical yoke 9a and the disk-shaped side yoke 1°a forming part of the magnetic path, and the drive unit with the printed wire 13a at the tip. A print head structure having the same structure as that described above, including the lever 11a, the back press plate 18, etc., is arranged in a stacked manner.

Here, the end surface 24 of the first stage of the function screw 23 that joins the back presser plate 18 and the nose 14 comes into contact with the end surface 21 of the nose 14, and the tightening amount of the step screw 23 is maintained constant. In this screw tightening portion, the dimensions of the step portion of the stepped screw are set so that a gap is created between the back presser plate 18, the temporary spring 25, and the nose 14. Further, the back pressing plate 18 is laminated on the side yoke 108L laminated on the yoke Oa,
The leaf spring 25 is made of an elastic material made of gold and has three legs that abut the back presser plate 18 at the center, extend from the center toward the outer circumference, and develop springiness in the thickness direction. The end that abuts the stepped screw 23 is attached to the outer end of the screw. Since the end portions are positioned by the service screws 23 and press the back press plate 18 at the center, the core blocks 5 and 5as yokes 9 and 5as stacked between the protrusion 3 of the nose 14 and the back press plate 18 are pressed. 9λ, fulcrum shafts 12 and 12a
1 presser plate 16 is clamped so that no gap is created.

A ring holding member 30.30a made of rubber or synthetic resin is held on the inner surface of the presser plate 16 and the back presser plate 18, with which the drive lever contacts during standby and positions the drive lever in the axial direction.

Next, the operation of the KW configured in this manner will be explained. When a current is applied to one or more drive coils 6 selected based on the print command signal, the drive lever 11 is caused by magnetic flux entering from the core 7 into the growing cylindrical yoke 9 and the side yoke lO. A suction force is generated between the armature 22 and the core 7, which are integrally attached, and the drive lever 11 rotates clockwise in the figure with the fulcrum shaft 12 as a fulcrum, and the printed wire 13 fixed at the tip is rotated. The vibration is applied to the printing paper via an ink ribbon (not shown).

In this way, the core block 5 and yoke 9 are placed inside the nose.
, side yoke 10, temporary presser foot 16, core block 5a
1 Yoke 9 a s Side yoke 10 a 1 Back presser plate 18 is layered 4 times, and each part is held between the nose 14 and the temporary spring 25, so even if there are variations in the axial dimensions of these parts, these parts can be It can be held without any gaps. In addition, the parts forming the magnetic circuit are installed in the nose, which is integrally made of metal and has cooling fins for heat radiation on the outer periphery, so that the heat generated by the magnetic circuit can be effectively dissipated.

〔Effect of the invention〕

As described above, according to the present invention, the core block, yoke, side yoke, and back presser plate are stacked in contact with each other with respect to the nose, and the back presser plate is attached to the nose by a temporary spring whose outer periphery is regulated in position. Since it is pressed toward the tip of the nose, it is possible to separate the parts so that there are no gaps between the nose, core block, yoke, side yoke, and holding plate, and they are held together by the spring force of the temporary spring, allowing the screws to be tightened. There is no deformation of the parts due to excessive force, and the position of these parts in the axial direction is uniquely determined by the axial dimension of each part, so it is possible to improve the positional accuracy of the armature with respect to the core block and yoke that form the magnetic circuit. It has become possible. As a result, variations in drive characteristics between each armature can be suppressed to a small extent, making it possible to provide an impact dot head with excellent print quality and less variation in density between printed dots.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus showing an embodiment of the present invention. 5.5a... Core block 9.9a..."Bottom cylindrical yoke 12.12a...Fulcrum shaft 14...Nose 14a... cooling fin 16... Presser plate 18... Back presser plate 23...Stepped screw 25...Temporary spring that's all

Claims (1)

[Claims] An impact dot head that attracts a clapper using electromagnetic force and prints using the striking force of the tip of a wire fixed to the clapper includes a nose with a fixed part formed at the outer end, a core block that comes into contact with the nose, and the core. A yoke that contacts the block, a side yoke that contacts the yoke, a back press plate that contacts the side yoke, and a leaf spring whose outer peripheral portion is positionally regulated with respect to the fixed part and presses the back press plate in the nose direction. An impact dot head characterized by having.