JPS6330262A - Dot printer head - Google Patents

Abstract

PURPOSE:To obtain good operational capacity and to facilitate manufacturing, by forming a recessed part to an auxiliary yoke so as to have opposed magnetic pole surfaces and fixing the leading end of a leaf spring to the bottom part of the groove of an armature wherein both side magnetic pole parts and the magnetic part facing the magnetic pole surfaces of the yoke form a C-shape. CONSTITUTION:A yoke 3 has a cross-sectional shape formed into a C-shape by inner and outer leg pieces 3a, 3b and a connection piece 3c and is integrally formed as a whole so that the connection piece 3c has a ring plate shape and the outer leg piece 3b has a cylindrical shape. An auxiliary yoke 4 has a recessed part 4b formed thereto so that opposed magnetic pole surfaces 4a, 4a performing the transfer of magnetic flux between said surfaces 4a, 4a and both side magnetic pole parts of an armature 6 mentioned hereinafter are provided at the position corresponding to the inner leg piece 3a and a magnetic gap (g) is interposed between the inner end containing the recessed part 4b and the end surface of the inner leg piece 3a. An armature 6 has a groove 6c formed thereto so that both side magnetic pole parts 6a, 6a and the magnetic pole part 6b facing the magnetic pole surface of the yoke 3, that is, the end surface of the inner leg piece 3a form a C-shape and the leading end of a leaf spring 5 is fixed to the bottom part 6d of the groove 6c. When a coil 2 is excited, the armature 6 is released from attraction by the spring force of the leaf spring 5 to allow a printing wire 7 to protrude and printing is applied to the paper 22 on a platen 21.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a dot printer head that performs printing by controlling the excitation of coils in a plurality of radially arranged magnetic paths and displacing an armature to which a printing wire is fixed. Regarding.

[Background Art 1] In this type of dot printer head, the fixing structure between the armature and the strip spring fixing the armature affects performance and manufacturing cost. In recent years, in order to reduce manufacturing costs, a method using laser welding for fixing the armature and leaf spring has been proposed, for example, in Japanese Patent Laid-Open No. 61-61866. As shown in Figures 4 and 5, the tip of a leaf spring C is laser welded to the magnetic pole face of armature B that faces the magnetic pole face of coke A, and therefore the leaf spring itself is also in the magnetic path. Since they are arranged in series, consideration must be given to prevent surface roughness, etc. that would cause a decrease in magnetic efficiency due to laser welding. D is an auxiliary yoke.

[Object of the invention].

The present invention has been made in view of the above-mentioned points, and its object is to provide a dot printer bed that provides good operational performance and is also easy to manufacture.

[Disclosure of the Invention] The dot printer head of the present invention includes a plate in which a coil, a yoke, an auxiliary yoke, a magnetic gap, etc. form one magnetic path, a plurality of magnetic paths are arranged radially in parallel, and the base end is fixed. In a do-no-do printer head in which an armature fixed to the tip of a spring is displaceably disposed within the magnetic gap of each magnetic path, the auxiliary yoke exchanges magnetic flux with the magnetic poles on both sides of the armature. A recess is formed to have opposing magnetic pole surfaces, and a groove is formed in the armature so that the magnetic pole portions on both sides and the magnetic pole portion facing the magnetic pole surface of the yoke form a U-shape. This is made by fixing the tip of the blade, which provides good operational performance and is easy to manufacture.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

1 is a dot printer head, coil 2. York 3. Auxiliary yoke 4. Leaf spring 5. The main components such as the armature 6 and the printing wire 7 are located in the housing 1). It is housed within 12.

The yoke 3 has a cross-sectional shape consisting of the inner and outer leg pieces 3a, 3b and the connecting piece 3.
It has a U-shape at C, but overall, the connecting piece 3C
has a ring plate shape, and the outer leg piece 3b has a cylindrical shape and is integrally formed. There are multiple inner grinding pieces 3a (usually 9 or 24 pieces)
are arranged radially at equal intervals, and are formed integrally with the cork 3 or press-fitted into the connecting piece 3c. The coil 2 is wound around each inner grinding piece 3a. A ring-shaped permanent magnet 8 is placed and fixed on the end surface of the outer leg piece 3b of the yoke 3.

The auxiliary yoke 4 has a ring plate shape with a width that overlaps the inner and outer leg pieces 3a and 3b of the yoke 3, and is arranged to overlap the outer leg piece 3b (permanent magnet 8 in this embodiment). Further, the auxiliary yoke 4 has a recess 4b so as to have opposing magnetic pole surfaces 4a, 4a at positions corresponding to the inner grinding piece 3a, through which magnetic flux is exchanged with both magnetic pole parts of the armature 6, which will be described later. A magnetic gap g exists between the inner end including the recess 4b and the end face of the inner grinding piece 3a.

Therefore, the yoke 3 around which the coil 2 is wound and the auxiliary yoke 4
forms one magnetic path with a magnetic gap g interposed therebetween, and a plurality of magnetic paths are arranged radially in parallel.

The armature 6 has a proximal end fixed to the tip of a leaf spring 5 which is sandwiched and fixed between the auxiliary yoke 4 and a permanent magnet, and is disposed so as to be displaceable within the magnetic gap g of each magnetic path, and has an arm 9 at one end.
The printing wire 7 is fixed through the . This amateur 6
A ta6c is formed in which the magnetic pole portions 6a, 6a on both sides and the magnetic pole portion 6b facing the magnetic pole surface of the yoke 3, that is, the end surface of the inner peripheral piece 3a, form a U-shape, and a plate spring is attached to the bottom 6d of this groove 6c. The tip of No. 5 is fixed.

13 is a printed wiring board, 14 is a shunt yoke that short-circuits the permanent magnet 8, 15 is a printing wire guide, 21 is a platen, 22 is paper, and 23 is an ink ribbon.

In such a dot printer head, when the coil 2 is not excited, the armature 6 is attracted to the end surface of the inner peripheral piece 3a of the yoke by the magnetic flux of the permanent magnet 8 against the spring force of the leaf spring 5. When the coil 2 is excited, the magnetic flux of the coil 2 cancels out the magnetic flux of the permanent magnet 8, and the armature 6 is released from attraction by the spring force of the leaf spring 5, causing the printing wire 7 to protrude and Print on paper 22.

Focusing on the flow of magnetic flux in the permanent magnet 8 or coil 2 during this operation, the magnetic flux φ1 from the inner grinding piece 3am surface of the yoke
enters the armature's magnetic pole part 6b through the magnetic gap g,
Then φ2. It separates into φ2, flows through both side magnetic pole parts 6a, 6a, and passes through the magnetic gap g to the opposing magnetic pole surface 4a of the auxiliary yoke.
, enters 4a.

In this case, there is also a flow of magnetic flux φ3 from the end surfaces of both magnetic pole parts 6a, 6a to the bottom surface of the recess 4b of the auxiliary yoke, but the area of the end surface is compared to the area facing the opposing magnetic pole surfaces 4a, 4a of the auxiliary yoke. Since the magnetic flux φ3 is sufficiently small, the magnetic flux φ3 is small. This magnetic flux φ3 corresponds to the required displacement movement of the armature 6.
Since it generates an opposite attractive force, it is preferable that the force be small, so that it is possible to suppress interference with high-speed operation.

In addition, the armature 6 has magnetic pole portions 6 on both sides that are effective for the flow of magnetic flux.
Since the grooves 6c are removed except for the magnetic pole portions 6a, 6a and the magnetic pole portion 6b, it is lightweight and contributes to high-speed operation.

Furthermore, the leaf spring 5 fixed to the armature 6 is not positioned in series with the magnetic path, and even if surface roughness or the like occurs during or after the fixing process, magnetic efficiency will not be reduced. This point is especially suitable when performing laser welding,
In other words, this fixing structure only needs to maintain fixing strength, so process control is simplified and manufacturing is facilitated.

In this embodiment, a polarized type having a permanent magnet has been described, but it is also applicable to a type without a permanent magnet.

[Effects of the Invention] The dot printer head of the present invention is a plate in which a coil, a yoke, an auxiliary yoke, a magnetic gap, etc. form one magnetic path, a plurality of magnetic paths are arranged radially in parallel, and the base end is fixed. In a dot printer head in which an armature fixed to the tip of a spring is movably disposed within the magnetic gap of each magnetic path, the auxiliary yoke has opposing magnetic pole surfaces that exchange magnetic flux with magnetic poles on both sides of the armature. A recess is formed in the armature, and a groove is formed in the armature so that the magnetic pole parts on both sides and the magnetic pole part facing the magnetic pole surface of the yoke form a U-shape. Since it is fixed, the flow of magnetic flux is favorable and the armature can be made lightweight and good operating performance can be obtained.Moreover, the leaf spring fixed to the armature is located in series with the magnetic path. This makes manufacturing easy.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the present invention, and Fig. 2 is a side view including a partial cross section, Fig. 2 is a perspective view of the main part, Fig. 3 is an enlarged view of the main part, and Fig. 4 is a side view including a partial cross section. , a side view of the main part of the conventional example, and FIG. 5 is an enlarged view of the main part. 1--Dot printer head, 2-Coil, 3-Yoke, 3a-Inner leg piece, 3b-Outer leg piece, 3c--Connection piece, 4-Auxiliary yoke, 4a, 4a--Opposing magnetic pole surface, 4b
- recess, 5 - plate spring, 6 - armature, 5a, 5a - both magnetic pole parts, 6b - magnetic pole part, 6C - groove, 6d - bottom of groove, 7 - printing wire, 1). 12---housing,
g - magnetic air gap. Patent applicant Matsushita Electric Works Co., Ltd. Agent Patent attorney Toshimaru Takemitsu (and 2 others) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) The yoke around which the coil is wound and the auxiliary yoke form one magnetic path with a magnetic gap in between, and multiple magnetic paths are arranged radially in parallel, and the base end is fixed at the tip of the leaf spring. In a dot printer head in which a fixed armature is displaceably disposed within the magnetic gap of each magnetic path, and a printing wire is fixed to the armature, the auxiliary yoke has a magnetic pole part on both sides of the armature. A recess is formed to have opposing magnetic pole surfaces between which magnetic flux is exchanged, and the armature includes:
A dot printer head, wherein a groove is formed such that both side magnetic pole parts and a magnetic pole part facing the magnetic pole surface of the yoke form a U-shape, and the tip of the leaf spring is fixed to the bottom of the groove of the armature.