JPH02223453A - Print head for printer - Google Patents

Abstract

PURPOSE:To lengthen the service life of a printer and to obtain a highly reliable print head by employing different materials having identical hardness for the armature and the core in the print head for a wire dot printer. CONSTITUTION:When a print head 1 does not perform printing operation, an armature 17 is attracted to the end face of a core 16 through the magnetic force of a permanent magnet 14 and a print hammer 7 is biased toward the core 16. When current is fed to a coil 13 and a magnetic field is produced in a reverse direction from the magnetic field of the permanent magnet 14 in order to cancel the magnetic field of the permanent magnet 14, the print hammer 7 is separated through a leaf spring being biased and a print wire 4 springs out from the tip of the nose 8 and collides against an ink ribbon and a print medium, thus forming a dot. Upon interruption of current supply to the coil 13, the armature 17 is attracted again to the core 16. When different materials having identical hardness are employed for the armature 17 and the core 16, friction on the colliding face is reduced, resulting in the improvement of the service life and the reliability of the print head 1.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a print head for a wire dot printer, and more particularly to a print head for a printer that has improved abrasion resistance of the armature and iron core of a printing magnet. .

(Prior Art) In recent years, various wire dot printers have been developed and put into practical use as printers for various computer terminals, word processors, and the like.

Wire dot printers operate the print head and form dots using printing wires to print characters, etc.
It is extremely suitable and economical for applications that require copying of many types of characters. In particular, as the use of the device as a terminal device such as an office computer is expanding, high reliability of the device is required.

Therefore, conventional printing and rad will be explained using a wire dot printer as an example. In a so-called spring-charged print head, the energy of a spring that is deflected by the attractive force of a permanent magnet is released by excitation of a coil to operate the print hammer. Repeat. Due to this dotting operation, the iron core for attracting the printing hammer and the corresponding attracting surface armature of the printing hammer collide with each other and slightly rub against each other. As a result, both wear quickly and the operating stroke of the printing hammer increases, resulting in malfunction of the printing hammer, leading to deterioration of printing quality, and increased stress in the spring, making it impossible to perform stable printing. It disappears. Furthermore, there is a problem in that abrasion powder is generated between the two, and as the dotting operation is repeated, this abrasion powder accumulates in the print head, causing various troubles.

In order to solve this problem, the conventional technique used was to insert a polyimide sheet between the armature and the iron core. The seat broke and a sufficient lifespan could not be obtained.

(Problems to be Solved by the Invention) In view of the above, an object of the present invention is to improve the drawbacks of the conventional device described above, extend the life of a wire dot printer, and provide a highly reliable printer print head. .

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides a print head in which the armature and the iron core are made of different materials having the same hardness.

Here, we will touch on the definition of a different material. Since the physical properties of a material are related to its structure, a different material can be considered to be a material with a different composition or crystal structure.

(Function) In the present invention, the armature and the iron core are made of different materials with the same hardness, thereby reducing wear on the collision surface and extending the life of the print head. This is because wear is closely related to the combination of materials, and metals that have good mutual solubility generally wear more significantly.

(Example) Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of a print head 1 of a dot printer according to the present invention, and FIG. 2 is a side view showing an enlarged main part thereof. The print head 1 consists of a driven 3 and a core 2. Driven 3 includes printing wire 4, lever 5,
An armature 17, a printing hammer 7 consisting of a leaf spring 6, a wire guide 12, a nose 8. It consists of spacers 9, 10 and a horizontal plate 11. The core 2 includes an iron core 16, a coil 13,
It consists of a permanent magnet 14 and a yoke 15.

Next, a method for assembling and processing the print head 1 will be explained. First, the armatures 17 to which the printing wire 4 is brazed to the tongues of the leaf spring 6 are brazed, and the printing hammer 7 is assembled by laser welding or the like. Next, the wire guide 12
The printing wire 4 is passed through the yoke plate 11, the spacers 9 and 10, and the nose 8 are assembled using screws or the like, and the wire guide 12 is bonded to the nose 8. After configuring as described above, the printing wire 4 is pushed and fixed by a predetermined amount onto the core side using a jig (not shown), and the back surface of the armature 17 is cut into a yoke so that it is flush with the core side surface of the yoke plate 11 using a milling machine or the like. Process.

By performing the above assembly and processing, the driven side of the print head is completed.

Next, a method for assembling the core will be explained.

The permanent magnet 14 and the yoke 15 are glued to the iron core 16, the coil 13 is attached to each iron core 16, and the iron core 16 and the yoke 1 are attached.
Process the end face of No. 5 with an icicle.

Next, the operation of this print head will be explained. First, when a printing operation is not performed, in the magnetic circuit composed of the permanent magnet 14, yoke 15, yoke plate 11, armature 17, and iron core 16, the armature 17 is attracted to the end face of the iron core 16 by the magnetic force of the permanent magnet 14. Therefore, the printing hammer 7 is biased toward the iron core 16.

Next, when performing a printing operation, a drive circuit (not shown) applies current to the coil 13 paired with the desired printing hammer 7 to generate a magnetic field in the opposite direction to the magnetic field of the permanent magnet 14. By canceling the magnetic field and eliminating the attractive force, the printing hammer 7 separates from the iron core 16 due to the biased leaf spring force, and the printing wire 4 moves away from the wire guide 12.
The ink is guided by the dot 8, protrudes from the tip of the nose 8, and collides with an ink ribbon (not shown) and a printing medium to form a dot. At this time, when the current applied to the coil 13 is cut off, the printing hammer is again moved to the iron core 16 by the attractive force of the permanent magnet 14.
is attracted to the paper and becomes non-printing.

Conventionally, in a print head that performs such an operation, there has been a problem of wear of the armature of the print hammer and the iron core due to collisions between the two at the contact portion.

In the present invention, for example, the armature 17 is made of permendur (Vickers hardness approximately 300), and the entire iron core 16 or the contact portion 19 with the armature is nitrided with 3% silicon mesh (Vickers hardness approximately 250). Made to match the hardness of permendur.

Here, it is better to make the armature out of permendur and the core out of nitrided 3% silicon steel. This is because both the iron core and the armature are processed into a single piece as described above, so nitriding is performed after the print head is assembled, but if the armature is nitrided, the spring will be distorted by heat, causing deterioration of the spring. This is because it will cause Furthermore, since the armature side has a higher magnetic flux density than the iron core, if the armature side is nitrided, the magnetic flux density will drop significantly and the performance will deteriorate. Furthermore, since the iron core is integrated, it is easier to perform nitriding treatment than the amateur type.

Thus, it is better to make the armature with permendur and the core with nitrided 3% silicon steel.

As a result, the materials that make up the armature and iron core can handle the 100 million or more printing operations required for a printing hammer.
Since the collision is not between materials of the same quality but of different materials having the same hardness, there is less wear on the collision surface, and the life and reliability of the print head can be improved.

[Effects of the Invention] According to the present invention, the life of the print head of a printer can be extended by using different materials with the same hardness to solve the problem of wear on the collision surface caused by the collision between the armature of the print head and the iron core. Can be done.

Furthermore, it is clear that this method also makes it easy to insert a buffer between the armature and the iron core.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of a print head of a dot printer according to the present invention, and FIG. 2 is a schematic side view of the print head.

Claims (1)

[Claims] In a print head consisting of an armature having a printing wire at one end and an electromagnet having an iron core that is provided opposite to the armature and that attracts the armature, the materials constituting the armature and the iron core are different materials with the same hardness. A printer print head characterized by: