JPS5881176A - Print needle drive device for printer - Google Patents

Abstract

PURPOSE:To provide a print needle drive device for a printer of which dimension of arrangement direction is small and print cycle is short by providing a magnetic circuit in parallel with a leaf spring, or by providing it separately as No.2 yoke. CONSTITUTION:The density of a magnetic flux to be generated by the magnetic motive force of a permanent magnet 102 passing through the gap between a core 110 and the top end of a leaf spring 104 is raised by closely encircling the outer circumference of an armature 105 with the internal surface of the conical hole 115a of No.2 yoke 115. When a permanent magnet 202 is arranged at the side opposite to the fixed end of a leaf spring 204, the magnet 202 can be arranged in close vicinity to the contact surface of the leaf spring 204. By fixing an armature 205 to the leaf spring 204 so that it pierces through the spring 204, a magnetic circuit can be composed without a leaf spring exist therein, and the leaf spring 204 can be composed with such a material which is nonmagnetic and excellent in spring characteristics.

Description

[Detailed Description of the Invention] The invention relates to an improvement in a printing machine in a data processing device,
In particular, by selectively colliding a plurality of printing needles facing the recording medium and arranged in a direction perpendicular to the conveyance direction of the recording medium with the recording medium while reciprocating in the direction in which the printing needles are arranged. The present invention relates to a printing needle drive device for a so-called impact type dot line printer that prints characters, figures, etc.

In general, when configured as a printer with a narrow printing width, a dot line printer is compact and inexpensive compared to a serial printer, and when configured as a printer with a wide printing width, it is expensive, but the processing time is short. There is. Utilizing these features (?), high-speed dot line printers with paper widths ranging from 15 inches to 1 inch are beginning to appear on the market, but the market demand for this high speed is increasing. In order to increase the printing speed of the dot line printer, it is necessary to shorten the printing cycle of the printing needles and to shorten the arrangement interval of the printing needles. In other words, in order to configure a dot line printer with high printing speed, a printing needle drive device that is small in size in the arrangement direction and has a short printing cycle is required.
The printing speed is determined by this degree of achievement. Recently,
BACKGROUND ART Fine-density impact type dot printers that print characters and symbols such as kanji, hiragana, katakana, numbers, and alphabets in a form similar to printed letters have become popular. In the fine-density type, the printing needle is thin, so by shortening the ζ marking period, the speed at which the printing needle collides with the recording medium increases, causing the compressive stress of the ink ribbon and the recording medium to exceed the allowable value. Therefore, it is necessary to improve such a drawback, and as a means of improvement, it is necessary to suppress the right equivalent mass of the printing needle portion to the smallest possible value.

(3) Conventionally, there is a printing needle drive device having a structure shown in FIG. 1 as a printing needle drive device having a small size in the arrangement direction and a short printing cycle. In FIG. 1, a leaf spring 4, which is made of a magnetic material and has a printing needle 6 and an armature 5 fixed to one end, is connected to a leaf spring fixing screw between a leaf spring support member 3 and a leaf spring holding member 8, which are made of a magnetic material. 9 is being squeezed and held in place. The leaf spring support member 3 is fixed to one magnetic pole surface of a permanent magnet 2, and the permanent magnet 2 is fixed to a yoke 1, which is a magnetic material, by the other magnetic pole surface. A core 10 made of a magnetic material is planted on the yoke 1, a coil 11 is wound around the core 1o, and one end faces one end of the leaf spring 4 to which the armature 5 is fixed, and the permanent magnet The magnetomotive force of 2 attracts and attracts one end of the leaf spring 4 against the restoring force of the plate spring 4. The coil 11 is connected to an electric circuit (not shown), and is configured so that when the coil 11 is energized, a magnetic flux is generated in a direction opposite to the direction of the magnetic flux due to the magnetomotive force of the permanent magnet 2.

Next, the above-mentioned conventional operation will be explained. 1st (4) When the coil 11 is energized for a certain period of time in the standby state shown in the figure, the attractive force acting between the tip of the core 10 and the tip of the leaf spring 4 disappears, and the tip of the leaf spring 4 disappears. moves to the right due to the restoring force of the plate spring 4, and the printing needle 6 hits a recording medium (not shown).

Therefore, in order to shorten the stamping cycle, it is necessary to increase the spring constant of the plate spring 4, and in order to attract and adsorb the tip of the plate spring 4, which has a high spring constant, to the tip of the core 10, The area of the tip of the core 10 and the armature 5 and the magnetic flux density of these parts need to be sufficiently large, and therefore the permanent magnet 2 needs to have a sufficient magnetomotive force.
The saturation magnetic flux density and magnetic path cross-sectional area of the magnetic path, ie, the yoke 1, core 10, and leaf spring 4, must be sufficiently large.

However, since the leaf spring 4 needs to be made of a material with high bending fatigue strength, steel is suitable, but steel has a low saturation magnetic flux density.
In addition, since the printing needle drive device needs to have small dimensions in the arrangement direction, the width of the leaf spring 4 is small and the thickness of the plate spring 4 is also limited by the allowable stress, so the cross-sectional area of the leaf spring 4, that is, the cross-sectional area of the magnetic path is small. (5) As a result, sufficient magnetic flux cannot be supplied to the attractive parts between the tip of the core 10, the armature 5, and the tip of the leaf spring 4, and therefore the attractive force between the core 10 and the armature 5 is reduced. Since the spring constant of the leaf spring 4 becomes low, it is not possible to shorten the stamping period.

In view of the above, an object of the present invention is to obtain a printing stylus drive device for an impact type dot line printer that has a small size in the arrangement direction and a short printing period.

The gist of the present invention for achieving the above object is to arrange a plurality of recording media in a direction perpendicular to the conveying direction of the recording medium, facing the recording medium, and moving the recording medium back and forth in the arrangement direction. A printing needle for printing characters, figures, etc. by selectively colliding with the printing needle, an armature made of a magnetic material that firmly holds the printing needle, a leaf spring that holds the armature at one end, and a plate spring. A core (6) made of a magnetic material that faces the back surface of the printing needle at one end and attracts and attracts one end of the mounting plate against the restoring force of the mounting plate spring; and a core that firmly holds the core. a first yoke made of a magnetic material; a permanent magnet fixed to the first yoke by one magnetic pole surface; and a permanent magnet that is magnetically coupled to the other magnetic pole surface of the permanent magnet and closely surrounds the outer periphery of the armature. and a second yoke made of a magnetic material with holes formed therein.

Embodiments of the configuration of the present invention will be described below based on the drawings. FIG. 2 is a sectional view showing the main structure of the first embodiment. In FIG. 2, a permanent magnet 102 is fixed at one magnetic pole surface to a first yoke 101 formed in a step shape by a magnetic material, and a flat plate shaped by a magnetic material is fixed to the other magnetic pole surface of the permanent magnet 102. Formed leaf spring support member 1
03 is fixed. A plurality of female threads are formed in the cedar plate spring support member 103, and a plurality of plate springs 104 formed in a rectangular shape made of spring steel are arranged at equal intervals on the back side of the surface to which the permanent magnet 102 is fixed. Arranged with 10 cedar leaf springs
Reference numeral 4 denotes a leaf spring holding spacer 10γ formed in a thin flat plate shape from a magnetic material, and a second plate spring holding spacer 10γ formed in a flat plate shape from a magnetic material.
The yoke 1-5 is inserted through the holes formed in the plate spring support member 103 corresponding to the female screws (7), and the diagonal spring fixing screws 1
One end is fixed with 09.

Note that the plate spring holding spacer 107 is attached to the second yoke 1.
It may be formed integrally with 15. Said leaf spring 104
At the other end, an armature 105 formed of a magnetic material and having a substantially conical shape is fixed at its bottom surface.
05 has an elongated hole formed from the top to the bottom,
The hole has a printing needle 1 formed into a cylindrical shape made of a wear-resistant material.
06 is inserted and fixed with its tip slightly protruding, and the outer periphery of the armature 105 is connected to the second yoke 1.
It is closely surrounded by the inner surface of a plurality of conical holes 115a formed in 15. Therefore armature 10
The gap between the armature 105 and the second yoke 115 is small and the opposing area is large, so although the magnetic resistance in the gap is low, the armature 105 has a small volume and therefore a small mass. A plurality of cores 110 formed in a cylindrical shape made of magnetic material are planted in the first yoke 1011, and the tips of the cores 110 are connected to the back side of the surface of the plate (8) to which the armature 105 of the spring 104 is fixed. , and is configured to attract the tip of the cedar leaf spring 104 by the magnetomotive force of the permanent magnet 102 against the restoring force of the mounting leaf spring 104. 1.The core 110 has a coil 1.
11 is wound around the coil 111, and the coil 111 is connected to an electric circuit (not shown), so that when the coil 111 is energized, a magnetic flux is generated in the opposite direction to the direction of the magnetic flux due to the magnetomotive force of the permanent magnet 102. It is composed of Furthermore, cover columns 112 made of a magnetic material are installed on the first yoke 101, one for each of the plurality of cores 110. The tip end face of the cover post 112 is formed on the same plane as the surface of the leaf spring holding member 107, and a cover 113 formed in a flat plate shape from a magnetic material covers both sides of the cedar leaf spring holding member 107 and the cover post 112. is attracted by the magnetomotive force of the permanent magnet 102. The cover 113 has a plurality of holes through which the tip of the armature 105 and the printing needle 106 pass, and the leaf spring (9), which is not shown, fits into the head of the fixing screw 109. A plurality of holes are formed to determine the position to be sucked. The printing needle drive device configured as described above is attached to a frame (not shown) so as to be movable back and forth in the direction in which the printing needles 106 are arranged, that is, in a direction perpendicular to the plane of the paper representing the drawing. It is connected to a reciprocating drive mechanism.

A cylindrical platen (not shown) is rotatably attached to a frame (not shown) opposite the printing needle drive device, and is connected to a paper feed mechanism (not shown). A recording medium (not shown) is wound around the platen, and the surface of the recording medium faces the printing needle 106 with a small gap therebetween via an ink ribbon (not shown).

Next, the operation of the first embodiment configured as described above will be explained. Although the present invention is a printing needle drive device for a dot line printer, explanation of the operation of the printer will be omitted, and only the operation of the printing needle drive device will be explained. In FIG. 2, the magnetic flux generated by the magnetomotive force of the permanent magnet 102 passes through a magnetic path consisting of the first yoke 101, the core 110, the air gap, the leaf spring 104 (10), and the leaf spring support member 103.
First yoke 101, core 110, gap, tip of plate spring 104, armature 105, gap, second yoke 115,
It passes through a magnetic path consisting of the leaf spring holding spacer 107, the fixed end of the leaf spring 104, and the leaf spring support member 1'03,
The magnetic flux flowing through the gap between the core 110 and the tip of the leaf spring 104 generates an attractive force between the core 110 and the tip of the leaf spring 104, and this attractive force causes the tip of the leaf spring 104 to It is adsorbed to the core 110 against the restoring force,
The printing needle 106 is in a standby state. Therefore, the conventional drawback shown in FIG. The lack of constant ′ and the resulting extension of the marking cycle have been improved as follows. That is, the leaf spring holding member 8 in the conventional example is extended to form a second yoke 115, and the inner surface of a substantially conical hole 115a formed in the second yoke 115 closely surrounds the outer periphery of the armature 105. As a result, (11) the gap between the armature 105 and the second yoke 115 is small and the opposing area is large, so the magnetic flux density passing through the gap between the core 110 and the tip of the leaf spring 104 is high. As a result, the suction force acting between the core 110 and the tip of the leaf spring 104 increases, and as a result, the leaf spring 1
04 has a high spring constant, and the core 1 acting between the armature 105 and the second yoke 115 has a high spring constant.
The component force of the suction force in the direction that opposes the suction force acting between the leaf spring 10 and the tip of the leaf spring 104 is also small.

Since the mater armature 105 has a conical shape, the fixed area with the plate spring 104 is large, and the fitting length with the printing needle 106 is long, so that the mater armature 105 is firmly fixed, and the volume of the armature 105 is comparatively small. The target is small and the mass is small. Next, the case of driving the printing needle 106 will be explained. When the coil 111 is energized for a certain period of time, the attractive force acting between the tip of the core 110 and the tip of the leaf spring 104 disappears, and the tip of the leaf spring 104 moves in the right direction due to the restoring force of the plate spring 104. The printing needle 106 hits a recording medium (not shown) wound around a plate (12) (not shown) through an ink ribbon (not shown). Therefore, as described above, the spring constant of the leaf spring 104 can be set large, and the mass of the tip of the leaf spring 104 is relatively small, so the natural frequency of the leaf spring 104 is increased, and the printing needle is higher than that of the conventional example. The marking cycle of 106 becomes shorter. In addition, since the natural frequency is high, the speed at which the printing stylus 106 collides with the recording medium increases, resulting in a higher printing force, and in the case of a fine density type, since the printing stylus 106 is thin, the compressive stress on the recording medium increases and the ink ribbon Although there is a risk of damaging the recording medium, since the armature 105 has a relatively small mass and the kinetic energy immediately before printing is small, the printing needle 106
Thin. The armature 105 can be used without damaging the ink ribbon or recording medium in a fine dot printer.
Appropriate printing force can be obtained by appropriately setting the mass of the plate, the spring constant of the plate spring 104, etc. In this way, the printing needle 106 collides with the platen through the ink ribbon and the recording medium, but just before the collision, the current to the coil (13) 111 is cut off and the coil (13) is turned off and the leaf spring 1 is turned off.
A suction force begins to act between 04 and 04. Therefore, printing needle 1
06 is the repulsive force caused by the collision, the core 110, and the leaf spring 1.
04, it is pulled back toward the core 110 against the restoring force of the leaf spring 104 and is attracted.

In this way, the printing needle drive device drives any printing needle 106 among the plurality of printing needles 106 at any position during reciprocating movement.
Then, by rotating the platen, the recording medium is moved, and by repeating this process, characters and figures are printed by combining the points appearing on the recording medium.

Next, a second embodiment of the present invention will be described. FIG. 3 is a sectional view showing the main structure of the second embodiment.

A plurality of leaf springs 204 are attached to the leaf spring holding plate 2 on a leaf spring support member 214 formed in an L shape from a non-magnetic material with low specific gravity.
08 and is tightened and fixed by a leaf spring fixing screw 209. Armatures 205 each formed in a cylindrical shape made of a magnetic material are fixed to the tips of the leaf springs 204, and (14) a printing needle 206 is fixed to the armatures 205. A first yoke 201 formed in a step shape from a magnetic material is fixed to the plate spring support member 201, and a permanent magnet 202 is fixed at one magnetic pole surface to the other end of the first yoke 201. A second yoke 215 made of a magnetic material and formed into a flat plate shape is fixed to the other magnetic pole surface of the permanent magnet 202 . The second yoke 215 is provided with a plurality of holes 215a that closely surround the outer periphery of the armature 205, and the second yoke 215 and the armature 20
By increasing the opposing area with 5 and making the gap small, the magnetic resistance of the gap is made small. A plurality of cores 210 formed in a cylindrical shape made of magnetic material are planted in the first yoke 201, and one end of the cores 210 faces the back surface of the printing needle 206 at the tip of the leaf spring 204. The structure is such that the magnetomotive force of the magnet 202 attracts and attracts the tip of the leaf spring 2'04 against the restoring force of the leaf spring 204. A coil 211 is wound around the core 210', and the coil 211 is connected to an electric circuit (not shown). By energizing the coil 211, the direction of magnetic flux due to the magnetomotive force of the permanent magnet 202 is reversed. It is configured to generate a magnetic flux in the direction. On the surface of the second yoke 215, there is a cover 213 formed in a flat plate shape from a magnetic material.
is attracted by the attractive force caused by the magnetomotive force of the excitation permanent magnet 202. The armature 205 is attached to the cover 213.
The tip of the cover 213 and the plurality of holes through which the printing needle 206 passes are fitted into the heads of the plate spring fixing screws 209, respectively, and the position where the cover 213 is attracted to the second yoke 215 is determined. A plurality of holes are formed. The printing needle drive device configured as described above is attached to a frame (not shown) so as to be able to reciprocate in the direction in which the printing needles 206 are arranged, in the same way as in the first embodiment described above. It is connected to a reciprocating drive mechanism (not shown). Also,
A cylindrical platen (not shown) is rotatably attached to a frame (not shown) facing the printing needle drive device, and is connected to a paper feeding mechanism (not shown).

A recording medium (not shown) is wound around the platen, and the surface of the recording medium faces the printing needle 206 with a small gap through an ink ribbon (not shown).

The operation of the second embodiment is almost the same as that of the first embodiment, so the differences will be explained below. The second embodiment differs from the first embodiment described above in two points: the first point is the arrangement position of the permanent magnet, and the second point is the shape of the armature. The permanent magnet 202 of the second embodiment has a core 210
In contrast, the fixed end of the leaf spring 204 is disposed on the opposite side. Therefore, the magnetic path can be shortened regardless of the length of the leaf spring 204, and the permanent magnet 202 can be connected to the attracting portion, that is, the core 210.
Since it can be placed close to the contact portion between the leaf spring 204 and the plate spring 204, the magnetic resistance is small and leakage magnetic flux is small. Also,
By fixing the armature 205, which is a magnetic material, to the cedar leaf spring 204 while penetrating the leaf spring 204, it is possible to insert the leaf spring 204 in the magnetic path. The material may be non-magnetic, and a material with excellent splash characteristics can be used. Furthermore, the armature 205 of the second (17) embodiment is cylindrical, and the hole 2151 of the second yoke 215 that closely surrounds the outer periphery of the armature 205 is also cylindrical. The mass of the armature 205 is large, the opposing area between the armature 205 and the inner surface of the hole 215a is large, and the first
In the embodiment, when the tip of the leaf spring 104 is attracted to the core 110, the gap between the armature 105 and the inner surface of the hole 115a becomes large;
The gap between the hole 215a and the inner surface of the hole 215a remains close and does not change. Therefore, the magnetic flux density in the suction part is high, and the spring constant of the leaf spring 204 can be set high, so in combination with the large mass of the armature 205, the kinetic energy of the printing needle 206 immediately before printing is large. In a high-speed dot printer with a thick printing needle 206,
Has sufficient print density and copying ability. Further, the armature 205 is cylindrical, and the hole 2 of the second yoke 215 is
Since 15a has a cylindrical shape, it is easy to process and can be manufactured at low cost and with high precision.

(18) As is clear from the above description, according to the present invention, the second plate spring, which is a bottleneck in the magnetic path in the conventional example, can be used in parallel with the plate spring, or separately when the plate spring is used as the magnetic path. By providing a magnetic path as a yoke, a printing stylus drive device having a small size in the arrangement direction and a short printing period can be obtained. In addition, by making the armature cylindrical, it provides sufficient print density and duplication in high-speed dot printers with large dot diameters, and prevents printing needles from breaking, ink ribbons, and recording in fine dot printers with small dot diameters. A printing stylus drive device that does not damage the medium and has appropriate printing power can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main structure of a conventional printing needle drive device, FIG. 2 is a cross-sectional view showing the main structure of a first embodiment of the present invention, and FIG. 19) It is a sectional view showing the main configuration. 101.201...first yoke, 102,202...
Permanent magnet, 104,204...plate spring, 105°20
5... Armature, 106,206... Printing needle,
115.215...Second yoke, 110,210...
・Core, 111, 211...Coil. (20)

Claims (2)

[Claims] (1) A plurality of pieces are arranged facing a recording medium in a direction perpendicular to the conveyance direction of the recording medium, and characters, figures, etc. A printing needle for printing, an armature made of a magnetic material that firmly holds the printing needle, a plate spring that holds the armature at one end, and a plate spring that faces the back surface of the printing needle at one end of the plate spring. A core made of a magnetic material for attracting and adsorbing one end of the leaf spring against the restoring force of the leaf spring, a coil wound around the core, and a first yoke made of a magnetic material that firmly holds the core. a permanent magnet fixed to the first yoke by one magnetic pole surface; and a magnetic material having a hole formed therein that is magnetically coupled to the other magnetic pole surface of the permanent magnet and closely surrounds the outer periphery of the armature. 1. A printing needle drive device for a printing machine, comprising: a second yoke consisting of a second yoke; (2) A printing needle drive device in a printing machine according to claim 1, wherein the armature is cylindrical.