JPH0612046U - Wire dot print head - Google Patents

Abstract

(57) [Summary] [Purpose] The joint structure between the armature and the leaf spring is improved to improve the high-speed response. [Structure] A joint between the free end of a flexible portion 27b formed on the leaf spring 7 and the armature 10 is formed between the rotation fulcrum portion 6b and the core 14, and the lower surface of the armature 10 is based on this lower surface. A step 21 corresponding to the thickness of the leaf spring 7 is provided by cutting out from the end, and the flexible portion 27b is provided in the step 21.
Were fixed in a state where they were in close contact with each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the structure of a wire dot print head in a serial printer.

[0002]

[Prior art]

 FIG. 5 is a schematic sectional view of a spring charge type wire dot print head in a conventional serial printer. This print head has a base 3 to which a substrate 2 is attached via a spacer 1 made of an insulating rubber packing or the like on the back side, a first yoke 4, a permanent magnet 5, and a base 3 which are stacked on the base 3. It is composed of two yokes 6, a leaf spring 7 for biasing, a spacer yoke 8, an armature yoke 9 and the like.

More specifically, the permanent magnet 5 is arranged on the outer edge portion of the base 3 so as to be sandwiched between the first yoke 4 and the second yoke 6, and the first yoke 4 and the second yoke 4 are arranged on the base 3. It is fixed with a screw 12 together with the york 6.

The second yoke 6 is formed in a substantially ring disc shape as a whole. A ring-shaped protrusion 6a for sandwiching and holding the leaf spring 7 with the spacer yoke 8 is integrally formed on the outer edge portion of the surface facing the leaf spring 7, and the inner edge portion has a protrusion 6a. A ring-shaped rotation fulcrum portion 6b is integrally formed so as to project in a ring shape in the same direction by an amount having substantially the same height.

The leaf spring 7 includes a ring-shaped main body portion 7 a which is fixed by being sandwiched between the protrusion 6 a of the second yoke 6 and the spacer yoke 8, and the number of the print wires 11 is equal to the inner side of the main body portion 7 a. A plurality of flexible portions 7b protruding toward the center of the spring 7 are integrally provided at substantially equal intervals. Of these, a notch hole 17 is provided in the substantially central portion of each flexible portion 7b as shown in FIG. 6, and the tongue is directed from the distal end side of the flexible portion 7b toward the main body portion 7a side. The blades 7c are integrally formed in a state of being extended into the cutout holes 17. Then, on the tongue-shaped blades 7c of each flexible portion 7b, the armatures 10 each having a printing wire 11 attached thereto are placed, and these are fixedly attached by spot welding or the like.

Further, on the base 3, cores 14 each having a coil 13 wound around the peripheral surface thereof are respectively attached and located below the armatures 10, and the lead terminals 15 of the respective coils 13 are attached. Each is soldered to a circuit (not shown) on the substrate 2.

Further, a wear-resistant magnetic metal sheet 16 is arranged on the core 14 so as to partially cover the rotation fulcrum portion 6 b of the second yoke 6.

The armature yoke 9 is formed in a ring shape and is provided on the spacer yoke 8. In addition, on the inner peripheral surface side of the armature yoke 9, a number of teeth 9 a corresponding to the number of the armatures 10 are formed so as to surround each armature 10 from both sides and project toward the center. ing.

Next, the operation of the wire dot print head will be described. First, in this wire dot print head, the magnetic flux of the permanent magnet 5 causes the magnetic flux of the first yoke 4, the base 3, the core 14, the leaf spring 7, the armature 10, the armature yoke 9, the spacer yoke 8, the leaf spring 7, and the second yoke 6. A magnetic circuit is formed therethrough which returns to the permanent magnet 5 again.

As a result, when the coil 13 is not energized, the armature 10 is attracted to the core 14 side by the magnetic flux of the permanent magnet 5, and the armature rotation center 18 (see FIG. 6) of the leaf spring 7 is attached to the rotation fulcrum portion 6b. Is contacted, and the tongue-shaped wing piece 7c is in contact with the armature rotating core 18 through the magnetic metal sheet 16 in parallel with the armature rotating center 18 as a fulcrum until the armature 10 is contacted. Is rotated together with the tongue-shaped wing piece 7c, and is held in a state with the flexible deformation of the flexible portion 7b. Further, due to this suction, the print wire 11 is drawn into a guide frame (not shown) and is in a standby state.

On the other hand, at the time of printing, a current is supplied to the coil 13 from the substrate 2 side for a short time to excite the coil 13. Then, during this excitation, the magnetic flux of the permanent magnet 5 is canceled and the force attracting the armature 10 disappears. When this suction force disappears, the flexible portion 7b of the leaf spring 7 that has been held in a bent state until then has the tongue-shaped blade with the armature rotation center 18 (see FIG. 6) as a fulcrum. While the piece 7c is returned to rotate, it moves together with the armature 10 toward the armature yoke 9 side. Then, the printing wire 11 fixedly attached to the tip of the armature 10 projects from the guide frame, and presses the ink ribbon and the printing medium (not shown) against the platen. As a result, characters and graphic patterns can be printed. Further, after the impact operation, the armature 10 is again sucked and held by the core 14 together with the flexible portion 7b.

By the way, today's printers are required to print at higher speed and with higher quality. In order to meet this demand, for example, a method of storing a strong force in the leaf spring 7 and opening it in a short time, a method of reducing the inertial mass of the driving portion, or the like can be considered.

[0013]

[Problems to be solved by the device]

 However, in the above-mentioned conventional structure, a part of the flexible portion 7b of the leaf spring 7 is arranged so as to overlap with the core 14, and this overlapped part is arranged in the magnetic path for attracting the armature 10. It is in the state of being Therefore, when trying to increase the thickness of the leaf spring 7, the spring material generally has lower magnetic characteristics than other magnetic materials, so the magnetic resistance increases and the flow of magnetic flux is obstructed, and the armature 10 is attracted. I can't cut it. Further, the portion inside the fulcrum (the armature rotation center 18) with which the leaf spring 7 rotates together with the armature 10 does not function as a spring, but merely contributes to the increase in the mass of the driving portion. .

The present invention has been made in view of the above points, and an object thereof is to improve a joint structure between an armature and a leaf spring, and to provide a print head excellent in high-speed response.

[0015]

[Means for Solving the Problems]

 In order to achieve the above object, the wire dot print head according to the present invention has a print wire attached to the free end side of a flexible part projecting toward the center from the main body part to which a leaf spring is fixed. The base end side of the armature is fixed, and the armature is magnetically attracted to the core side together with the flexible part with the pivotal fulcrum part provided between the main body part and the core as a fulcrum. The printing wire is held in rotation while accumulating the bending energy, the magnetic attraction is released during the printing operation, and the printing wire is impacted by releasing the accumulated bending energy of the flexible portion. A joint between the free end of the flexible portion and the armature is formed between the rotation fulcrum portion and the core, and the lower surface of the armature is cut out from the base end. A step corresponding to the thickness of the serial plate spring provided, in which a fixed and formed by composed of the flexible portion contact is brought into contact with the step. Further, when the armature is provided so as to be inclined at a predetermined angle with respect to the flexible portion in a direction in which the tip end side of the armature is separated from the surface of the core, the armature is arranged to be inclined with respect to the core, and the armature is It is possible to have a structure in which the flexible portion is held in a state in which the bending energy is stored when it is sucked into the flexible portion.

[0016]

[Action]

 According to this configuration, since the joint between the free end of the flexible portion and the armature is formed between the rotation fulcrum portion and the core, the leaf spring causes the magnetic flux of the attracted magnetic flux and the drive portion, that is, the core. The structure does not wrap around the upper part of the. As a result, a leaf spring having a large thickness and a strong spring force can be adopted without worrying about a decrease in attraction force and an increase in inertial amount. In addition, in the notch formed on the lower surface of the armature, the surface on which the leaf spring is closely attached is formed with an angle, and when the leaf spring and the armature are in close contact, the armature is attached to the leaf spring 7. When the armature is fixed by tilting by the angle θ, the flexure energy is stored in the leaf spring while the armature is attracted to the core, and the upper contact surface of the core and the contact surface of the rotation fulcrum part are The process for forming a step between the leaf spring and the fixed portion that holds the leaf spring is not necessary.

[0017]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 show a wire dot print head according to an embodiment of the present invention. FIG. 1 is a schematic sectional view thereof, FIG. 2 is an enlarged perspective view of an essential part thereof, and FIG. 3 is an enlarged plan view of the essential part thereof. Is. Further, in FIGS. 1 to 3, the same reference numerals as those in FIGS. 5 and 6 denote the same as those in FIGS.

A major difference between the conventional print head shown in FIGS. 5 and 6 and the print head of the present embodiment lies in the joint structure of the armature 10 and the leaf spring 7, and the others are almost the same. It has the same structure. Therefore, in the following description, duplicated description of the parts configured with the same structure as in FIGS. 5 and 6 will be omitted, and different points will be mainly described.

In the print head shown in FIGS. 1 to 3, the print head is integrally formed toward the center from the main body portion 7a of the leaf spring 7 which is fixed by being sandwiched between the protrusion 6a of the second yoke 6 and the spacer yoke 8. A part of the flexible portion 27b (the armature rotation center 18) is brought into contact with the rotation fulcrum portion 6b through the magnetic metal sheet 16, and the rotation reaction force at this contact portion can be received. At the same time, in order not to interfere with the flow of the magnetic flux by being interposed in the magnetic path of the magnetic flux attracted by the permanent magnet 5, that is, just above the core 14, the magnetic flux is not extended right above the core 14, and the rotation fulcrum portion 6b is provided. It is formed in a state in which it is extended to the upper position of and stopped. Further, a cutout hole 17 is formed in a substantially central portion of the flexible portion 27b, and the tongue is extended in the cutout hole 17 from the tip end side of the flexible portion 27b toward the main body portion 7a side. The blades 27c are integrally formed.

On the other hand, the armature 10 attached to the flexible portion 27b of the leaf spring 7 is provided with a notch on the lower surface at the base end side by the thickness of the leaf spring 7, and a step 21 is formed by this notch. There is. Then, the flexible portion 27b of the leaf spring 7 and the tongue-shaped wing piece 27c are set in the step 21 in a state of being brought into close contact with the armature 10 and further fixed by laser welding.

In the present embodiment, since the step 21 is formed by the thickness of the leaf spring 7, the leaf spring is provided on the lower surface side of the armature 10 when the leaf vane 7 and the armature 10 are fixed. 7 and the armature 10 are flush with each other. This is because in the print head of this embodiment, a step is formed between the rotation fulcrum portion 6b and the protrusion 6a of the second yoke 6 fixing the leaf spring 7, and the armature 10 is attracted to the core 14. This is because the bending energy is stored in the flexible portion 27b of the leaf spring 7 in this state.

That is, when the lower end surface of the armature 10 and the lower end surface of the leaf spring 7 are not flush with each other and there is a step, the upper surface of the core 14 and the upper surface of the rotation fulcrum portion 6b are adjusted according to the step amount. This is because it is necessary to adjust the height difference between the second yoke 6 and the protrusion 6a, which makes it extremely difficult to manufacture the print head.

The wire dot print head thus configured operates in substantially the same manner as the print heads shown in FIGS. 5 and 6. Therefore, the operation of the print head in this embodiment will be described below. First, in this wire dot print head, the magnetic flux of the permanent magnet 5 causes the magnetic flux of the first yoke 4, the base 3, the core 14, the leaf spring 7, the armature 10, the armature yoke 9, the spacer yoke 8, the leaf spring 7, and the second yoke 6. A magnetic circuit is formed therethrough which returns to the permanent magnet 5 again.

As a result, when the coil 13 is not energized, the armature 10 is attracted to the core 14 side by the magnetic flux of the permanent magnet 5, and the armature rotation center 18 of the leaf spring 7 (FIG. 2 and FIG. 3)) is abutted, and the armature 10 is parallel to the tip end surface of the core 14 with the tongue-shaped wing piece 27c via the magnetic metal sheet 16 with the abutted center of the armature rotation center 18 as a fulcrum. It is rotated until it comes into close contact with and is held in a state with the flexible deformation of the flexible portion 27b. Further, due to this suction, the print wire 11 is drawn into a guide frame (not shown) and is in a standby state.

On the other hand, at the time of printing, a current is supplied from the substrate 2 side to the coil 13 for a short time to excite the coil 13. Then, during this excitation, the magnetic flux of the permanent magnet 5 is canceled and the force attracting the armature 10 disappears. Further, when this suction force is lost, the flexible portion 27b of the leaf spring 7 that has been held in a bent state up to that point has the armature rotation center 18 (see FIGS. 2 and 3) as a fulcrum. , And moves with the armature 10 toward the armature yoke 9 side while the tongue-shaped wing piece 27c is returned to rotate. Then, the printing wire 11 fixedly attached to the tip of the armature 10 projects from the guide frame, and presses the ink ribbon and the printing medium (not shown) against the platen. As a result, it is possible to print characters and graphic patterns. Further, after the impact operation, the armature 10 is again suction-held on the core 14 with the flexible portion 27b being bent.

Therefore, according to the wire dot print head of this embodiment, the joint between the free end of the flexible portion 27 b and the armature 10 is formed between the rotation fulcrum portion 6 b and the core 14, and the leaf spring 7 is formed. Has a structure in which the magnetic flux does not wrap around the magnetic path portion and the drive portion of the attracted magnetic flux, that is, the upper part of the core 14, so that there is no need to worry about a decrease in attractive force and an increase in inertial mass. As a result, the plate spring 7 having a large plate thickness and a strong spring force can be employed, and the high speed response can be improved by utilizing this strong spring force.

According to the experiment, when the structure in which the leaf spring does not exist in the magnetic path of the attracted magnetic flux as in the present embodiment, the attraction force is approximately the same as that of the conventional structure in which the leaf spring is interposed. Good results have been obtained, with an increase of about 10% and a reduction of the inertial mass of the driving part by about 15%.

FIG. 4 is an enlarged side view of essential parts showing a modified example of the joint structure of the leaf spring 7 and the armature 10 in the dot print head according to the present invention. In the modification shown in FIG. 4, in the step portion 21 formed by the notch formed on the lower surface of the armature 10, the surface on which the leaf spring 7 is closely contacted is angled so that the leaf spring 7 and the armature 10 are separated from each other. The armature 10 is formed so as to be fixed to the leaf spring 7 at an angle of θ with the leaf spring 7 in close contact with each other. Therefore, in the case of this modified example, with the armature rotation center 18 of the leaf spring 7 in contact with the rotation fulcrum portion 6b, the armature 10 is inclined by the angle θ with respect to the upper surface of the rotation fulcrum portion 6b. Since it is arranged, it is not necessary to provide a step between the upper surface of the core 14, the upper surface of the rotation fulcrum portion 6b of the second yoke, and the surface of the protrusion 6a of the second yoke as in the above embodiment.

[0029]

[Effect of device]

 As described above, according to the print head of the present invention, since the joint between the free end of the flexible part and the armature is formed between the rotation fulcrum part and the core, the leaf spring causes the absorption magnetic flux to be absorbed. It has a structure that does not go around the magnetic path portion and the drive portion, that is, the upper portion of the core. As a result, a leaf spring with a large thickness and a strong spring force can be adopted without worrying about a decrease in suction force and an increase in inertial mass, and a leaf panel with this strong force is used. By doing so, the printing operation is accelerated and high-speed printing becomes possible. Also, in the notch part formed on the lower surface of the armature, the surface on which the leaf spring is closely attached is formed with an angle, and the armature is attached to the leaf spring 7 with the leaf spring and the armature in close contact with each other. Since the armature is fixed by being tilted by an angle θ, the structure is such that the flexural energy is stored in the leaf spring when the armature is attracted to the core. There is no need to provide a step between the two yokes.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a wire dot print head shown as an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of this embodiment.

FIG. 3 is an enlarged plan view of a main part of this embodiment.

FIG. 4 is a side view showing a modified example of the present embodiment.

FIG. 5 is a schematic sectional view showing an example of a conventional print head.

6 is an enlarged top view of a main part of the print head shown in FIG.

[Explanation of symbols]

 5 permanent magnet 6 second yoke 6b rotation fulcrum part 7 leaf spring 7a main body part 10 armature 11 printing wire 13 coil 14 core 18 armature rotation center 21 step 27b flexible part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Kiyoshi Ikeda 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A base end side of an armature having a print wire attached to a tip thereof is fixed to a free end side of a flexible portion projecting toward a center from a main body portion to which a leaf spring is fixed, and the body portion is provided. The armature is magnetically attracted to the core side together with the flexible part with the rotary fulcrum part provided between the core and the core as a fulcrum, and the flexible part is rotatably held in a state in which flexural energy is stored, and a printing operation is performed. In a wire dot print head for impacting the print wire by releasing the magnetic attraction at the time when the magnetic attraction is released, the joint portion between the free end of the flexible portion and the armature is It is formed between the rotation fulcrum portion and the core, and a step corresponding to the thickness of the leaf spring is provided on the lower surface of the armature by cutting out the lower surface from the base end. Wire dot printing head is characterized by comprising fixed by the flexible portion contact is brought into contact with the step. 2. The wire dot print head according to claim 1, wherein the armature is provided so as to be inclined at a predetermined angle with respect to the flexible portion in a direction in which a tip end side of the armature is separated from a surface of the core.