JPH0354918Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an improvement of a printing head in a dot printer.

[Prior art]

Traditionally, this type of printhead has a print wire, a print wire guide, a print wire drive magnetic core, a yoke, a magnet coil, and a permanent magnet, one for each print wire, and has a complicated component loading system. It was designed to be rarely engaged. Therefore, the number of component parts is very large, which results in a large size, and the number of work steps for tightening screws and rivets increases, requiring a large number of man-hours. Therefore, the following is disclosed in Japanese Patent Application Laid-Open No. 56-37176. That is, N cores equipped with magnetic coils are fixed to the first plate. Next, a ring-shaped permanent magnet is fixed to the first plate, a second plate is fixed to the ring-shaped permanent magnet, and an oil felt is further inserted to form a first assembly. Further, N printed wires are each fixed to a different armature, and each armature is fixed one by one to the upper surface of the N divided pieces of the leaf spring to form a second assembly. Next, the upper surface of the second plate of the first assembly or the upper end surface of the core is polished so that the upper surface of the second plate and the upper end surface of the core are flush with each other. A spacer, a second assembly, a yoke plate, and a guide frame are sequentially stacked on top of the finished first assembly, and the print wire is inserted into the guide hole of the guide frame. Thereafter, the second assembly is mounted in a stacked state by screwing the mounting screws into the screw holes of the second plate through the respective holes of the guide frame, yoke plate, leaf spring, and spacer. With this configuration, when the magnet coil is not energized, the armature is attracted to the upper end surface of the core by the magnetic force of the ring-shaped permanent magnet, and the divided pieces of the leaf spring are biased and attracted to the core. Next, when the magnet coil is energized, the magnetic flux from the magnet coil cancels the magnetic flux from the ring-shaped permanent magnet, so that the divided pieces of the leaf spring that are biased against the core are released from the core. Therefore, the print wire fixed to the armature protrudes from the guide frame and strongly presses the ink ribbon of the printer against the printing paper, making it possible to print dots (see Figures 1 and 2 of Japanese Patent Laid-Open No. 56-37176).
(see figure).

[Problem that the invention attempts to solve]

In JP-A-56-37176 described above, the outer periphery of a leaf spring having an armature fixed to the upper surface of the divided piece is held between a spacer and a yoke plate to form a spring fulcrum, and the N
The yoke plate is configured to include a yoke plate in which each divided piece extends toward the center and has a groove larger than the width of the armature fixed to the leaf spring. Therefore, the print head has an unresolved problem that it is difficult to downsize the print head due to its large thickness in the printing direction and large diameter in the diametric direction. In addition, the magnetic flux of the permanent magnet is
A magnetic path consisting of spacer, leaf spring, yoke plate, armature, leaf spring, core, first plate, and ring-shaped permanent magnet is formed. For this reason, it also had economical problems such as a large number of magnetic circuit components and high prices.

This idea was made in view of the above-mentioned problems.

That is, a printed wire is fixed to one end of the armature, the leaf spring at the free end is always in a spring-charged state, guide pieces are provided for positioning the armature, and the armature moves using the outer periphery of the core as a branch line. The purpose of the present invention is to provide an economically superior print head that has a cutout groove formed on the upper end surface of the yoke to make it possible to reduce the size of the print head, and also has a simplified magnetic circuit that eliminates the problems of conventional models. shall be.

[Means for solving problems]

This idea consists of a yoke 1 made of a magnetic material and having notched grooves 1a formed at equal intervals on the upper end surface of its outer periphery, a permanent magnet 2 on a ring having magnetic poles in the vertical direction, and a plurality of cores 3c along the radial direction. A core member 3 having magnetic coils 4 arranged in the direction and having magnetic coils 4 fitted into its core, and an armature 5 having its base end fitted into each notch groove of the yoke and having the base end of a printed wire 7 fixed to its tip.
and a guide member 8, which is made of a non-magnetic material, has a through hole 9c in the center through which the base end of the print wire passes, and has a supporting member 10 fixed thereto that communicates with the through hole and guides the tip of the print wire to the printing part. 9 and 9 are sequentially stacked vertically and fixed, a pressing piece 3d that separately projects upwardly from above each core, a hole 5d formed in the intermediate part of the armature so as to pass through the pressing piece, A notched groove 5a formed on both side edges of the armature between the base end of the armature and the hole, a leaf spring 6 facing the pressing piece having one end fixed to the base end of the armature and the other end penetrating through the hole in the armature; A guide piece 8d is provided on the guide member to guide both sides of the tip of the armature, and a guide piece 8d is loosely fitted into the notch groove of the armature to regulate the vertical and lateral directions so that the base of the armature serves as a rotation branch line to the outer peripheral edge EF of the core 3c. It is characterized by having a guide piece 8c having a flat surface and a projection 8e.

[Example] FIG. 1 is an exploded perspective view showing this invention.
In FIG. 1, 1 is a yoke that forms a common magnetic path, and the upper end surface of the circular ring has N pieces (N=1
8, 9, and 24), and the center of the bottom portion 1b thereof is provided with a take-out hole 1c for a flexible electric wire of a magnet coil, which will be described later. 2 is a ring-shaped permanent magnet fixed to the bottom part 1b of the yoke 1, and 3 is a ring-shaped small diameter part 3a and a ring-shaped large diameter part 3b having flanges in the inner and outer circumferential directions with respect to the small diameter part 3a. It is a core member provided and is fixed to the upper surface of the permanent magnet 2. The small diameter portion 3a of this core member 3 has N cores 3c extending from the outer periphery toward the center.
A pressing piece 3d is press-fitted into the center of the upper end surface of each of the N cores 3c. Also,
N magnetic coils 4 are connected to N cores 3c.
The electric wires at the start and end of winding of each magnet coil 4 are collected into a flexible electric wire and wired to the outside from the take-out hole 1c of the yoke 1. At this time, the base line A-B in the center direction of the core 3c of the small diameter portion 3a of the core member 3 is aligned with the base line A-B with respect to the center of the notch groove 1a of the yoke 1, and
The ring-shaped permanent magnet 2 is assembled as shown in FIG. 2 using an assembly jig using the extraction hole 1c as a reference hole, and the ring-shaped permanent magnet 2 is magnetized in the vertical direction of the center using a magnetizer (not shown). Incidentally, adhesive or pin engagement may be used to fix the yoke 1, the ring-shaped permanent magnet 2, and the core member 3 to each other. 5 is the armature, the third
Shown in perspective view in the figure. Approximately in the center of the armature 5 is a hole 5 corresponding to the pressing piece 3d of the core 3c.
d and the flat surface of the stepped portion 5b at the base end of the armature 5, that is, one free end, and the hole 5d, there are cutout grooves 5a formed on both side edges of the armature.
A plate spring 6 is fixed to the base end of the armature 5 by spot welding or the like, and a printed wire 7 is fixed to the tip of the protrusion 5c at the other end of the armature 5. Next, the base line A-B of the armature 5 is aligned with the base line A-B of the core member 3, and the pin 3d is passed through the hole 5d.
When the N armatures 5 are set so as to be located in the space of the notched groove 1a of the yoke 1, each of the N armatures 5 will extend toward the center.

Reference numeral 8 denotes an armature guide, which is molded, for example, from reinforced resin containing glass fiber, etc., and has a hole 8b in the center of its base 8a and N guide pieces extending downwardly on the outer and inner peripheries of the back side. 8c and 8d, and a protrusion 8e is provided at the tip of the guide piece 8c.
FIG. 4 is a perspective CD sectional view of the armature guide 8 of FIG. 1.

Reference numeral 9 denotes a guide plate having a flange portion made of a lightweight non-magnetic material such as a light alloy, and a base portion 9a thereof is provided with a plurality of mounting holes 9b in the flange portion and a through hole 9c in the center portion.

Reference numeral 10 denotes a head support member, which includes a substrate 10a having N holes arranged in one or two rows for guiding the printed wire 7, and a guide plate 1 having oval holes.
0b and a mounting hole 10c for fixing the print head to the base of the dot printer's carriage (not shown).
Equipped with.

Next, the guide plate 9 and the armature guide 8 are fixed together (adhesive may be used). next,
In the combined member of the guide plate 9 and the armature guide 8, the cylindrical flange surface of the guide plate 9 is placed on the upper end surface of the yoke 1 (normally, the mounting hole 9b of the guide plate 9 and the yoke 1
with the threaded part 1d using a jig). Therefore,
The N armatures 5 each have a protrusion 5c.
The guide piece 8d of the armature guide 8 is guided between them. On the other hand, the flat surface of the guide piece 8c is brought into contact with the base of the armature 5 on the outer peripheral edge EF of the core 3c, and the protrusion 8e of the guide piece 8c is placed in each notch groove 5a of the N armatures 5. is loosely fitted to guide the N armatures 5 (see FIGS. 5a and 5b). Furthermore, the leaf spring 6 of the armature 5 is pushed up by the pressing piece 3d provided on the core 3c and is spring-tied. Thereafter, the plurality of mounting screws 12 are screwed into the plurality of threaded portions 1d provided on the upper end surface of the yoke 1 through the holes 9b. Next, the print wire 7 is inserted into the hole in the substrate 10a of the head support member 10 using a jig such as tweezers while being held in place.
Attach it to the guide plate 9 by screwing it with the screw 11. FIG. 6 is a cross-sectional view of the print head assembled in this manner.

[Effect]

The operation of the configuration described above will be explained based on FIG. 6. First, when the magnet coil 4 is not energized, the armature 5 is attracted to the upper end surface of the core 3c by the magnetic force of the ring-shaped permanent magnet 2, overcoming the elastic force of the leaf spring 6. At this time, the magnetic flux of the ring-shaped permanent magnet 2 is
Yoke 1 - Armature 5 - Core member 3 (Core 3
c) - through the magnetic path of the ring-shaped permanent magnet 2; next,
When the magnet coil 4 is energized, the magnetic flux generated by the magnet coil 4 is applied to the ring-shaped permanent magnet 2.
At the same time, the armature 5 is released from the core 3c by the elastic force of the leaf spring 6. Therefore, the print wire 7 fixed to the armature 5 protrudes from the substrate 10a of the head support member 10 through the hole 9c of the guide frame 9, and an ink ribbon (not shown) is strongly pressed against the printing paper to print dots.

The armature 5 is attached to the guide piece of the armature guide 8 so that the outer peripheral edge of the upper end surface of the core 3c (EF in FIGS. 2 and 5 a) becomes a rotation branch line (hereinafter referred to as a branch line (fulcrum)). 8d is the protrusion 5
c, and while the flat surface of the guide piece 8c is in contact with the surface base of the branch line EF of the armature 5, the protrusion 8e of the guide piece 8c is loosely fitted into the notch groove 5a, and the protrusion 8e of the guide piece 8c is loosely fitted into the notch groove 5a to guide the armature 5 in the vertical and lateral directions. While being restricted, the leaf spring 6 is pushed up by the pressing piece 3d provided on the core 3c and is spring-shirred. Therefore, the armature 5 can move while being constantly charged with a spring without flapping of the branch line (fulcrum). Therefore, the protruding portions 5c of N armatures 5
The printing stroke between the N print wires 7 fixed to each other is set smaller than the stroke due to spring displacement, and is regulated by the printing paper surface on a platen (not shown), so that uneven printing density does not occur. In addition, the leaf spring 6 is connected to the armature 5
Since the cross-sectional area of the fixed end extending from the proximal fixed end toward the center can be increased, the spring constant can be set high within the permissible applied force range, making it possible to increase the speed of the printing head.

In the above description, the armature guide 8, the guide plate 9, and the head support member 10 are each constructed individually, but they may be integrally formed as a print head guide member made of a non-magnetic material such as a light alloy.

In this case, it is preferable to insert the armature 5 into the print head member, assemble the print wire 7 to the head support member 10 using tweezers, and then assemble the assembly as shown in FIG.

[Effect of idea]

As explained in detail above, this invention consists of an armature 5 having one end fixed to the base end of the armature and the other end having a plate spring 6 opposed to the pressing piece 3d projecting upward from the core 3c passing through the hole 5d. Since the base end of the leaf spring 6 is fitted into the notched groove 1a of the yoke 1, the spring constant of the leaf spring 6 can be set high within the allowable stress range, and the spring constant is always in the spring charge state, and the guide pieces 8c and 8e for positioning the armature 5 are The armature 5 is configured to be movable using the outer peripheral edge EF of the core 3c as a rotation branch line. As a result, even if the outer diameter of the yoke 1 is reduced, the plate spring 6 can have a sufficient cross-sectional area at its fixed end, making it possible to downsize the printing head. In addition, the armature 5 does not fluctuate due to the vertical and lateral regulations, and the leaf spring 6 can be set to a high spring constant within the allowable stress and is constantly charged, so there is no uneven printing and the printing head can be run at high speed. It produces effects such as summer.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of the print head of the present invention;
Figure 2 is a partially assembled perspective view of the core member, magnetic coil, permanent magnet, and yoke of the present invention, Figure 3 is a perspective view of an armature equipped with the leaf spring and printed wire of the present invention, and Figure 4 is a perspective view of the armature equipped with the leaf spring and printed wire of the present invention. , the first part of this invention
5A and 5B are explanatory views showing the mounting positional relationship of the armature of the present invention, and explanatory views showing the relationship between the base of the armature and the guide piece, and FIGS. The figure is a cross-sectional view of the print head of the present invention.

Claims (1)

[Claims for Utility Model Registration] A yoke 1 made of a magnetic material and having notched grooves 1a formed at equal intervals on the upper end surface of its outer periphery, and a permanent magnet 2 on a ring having magnetic poles in the vertical direction.
A core member 3 in which a plurality of cores 3c are arranged in the radial direction and magnetic coils 4 are fitted into the cores; A support member 10 is fixed to the armature 5, which is made of a non-magnetic material, has a through hole 9c in the center through which the base end of the print wire is passed, and communicates with the through hole to guide the tip of the print wire to the printing part. In the printing head in which the guide members 8 and 9 are sequentially superimposed and fixed in the vertical direction, a pressing piece 3d is formed in the intermediate part of the armature so as to penetrate the pressing piece 3d, which projects upwardly from above each core. a notched groove 5a formed on both sides of the armature between the base end of the armature and the above-mentioned hole, and a plate facing a pressing piece having one end fixed to the base end of the armature and the other end passing through the hole in the armature. A spring 6, a guide piece 8d that is provided on the guide member and guides both sides of the tip of the armature, and a guide piece 8d that loosely fits into the notch groove of the armature so that the base of the armature becomes a rotation branch line on the outer peripheral edge EF of the core 3c.・
A print head characterized by comprising a flat surface for regulating the lateral direction and a guide piece 8c having a protrusion 8e.