JPS599355B2 - Printer character selection electromagnetic mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small printer, and more particularly to a character selection electromagnetic mechanism using permanent magnets.

FIG. 1 is a schematic diagram showing a conventional embodiment of a character selection electromagnetic mechanism for a printer using a type wheel. 1 is the type wheel and the drive shaft 4
It is frictionally coupled or spring-coupled by a spring or the like, and rotates in the direction of arrow A as the drive shaft 4 rotates.

Characters, symbols, etc. are arranged around the type ring 1, and when the desired type 2 appears at the printing position, the electromagnet 8 is energized and the suction plate 11 is operated in synchronization with this, and until then the selection claw 5
The actuating plate 12 that has been locking also moves in the direction of arrow B. Therefore, the selection pawl 5 rotates around the selection pawl shaft 6 in the direction of arrow C under the action of the leaf spring T, engages with the ratchet 3 of the type wheel 1, and locks the type wheel 1. The locked type wheel 1 remains stationary, but the type wheel 1 and drive shaft 4, which have not been selected yet, continue to rotate. When character selection for each digit is completed in this way, the platen 14 moves the ink ribbon 15 and the printing paper 1.
6 to press against the type 2, and the printing process is completed. After printing, the selection claw 5 is reset by rotating the reset lever IT in the direction of arrow D. The above is the basic operation of the conventional character selection electromagnetic mechanism. As shown in FIG. 12, a return spring 13 for the actuating plate 12, etc., resulting in a complicated structure.

In addition, in terms of power consumption, the iron core 9 and the suction plate 11 face each other with a gap in between, and are operated by mutual attraction, so a relatively large amount of power is required. In addition, in order for the suction plate 11 to operate, it was necessary to overcome the friction load between the selection pawl 5 and the actuation plate 12 due to the plate spring T and the spring load of the return spring 13. This was also a factor in increasing power consumption and lengthening the operating time. An object of the present invention is to obtain a highly reliable character selection electromagnetic mechanism that suppresses variations in magnetic properties for each digit and has uniform operating characteristics.

Another object of the present invention is to obtain a character selection electromagnetic mechanism that has short operating time and low power consumption.

The present invention will be specifically explained below.

FIG. 2 is a schematic diagram of an electromagnetic device unit which is the basis of the present invention.

A movable member 20 is composed of an iron core 21, a selection claw 22, and an arm 23, and is rotatably mounted around a selection claw shaft 24.

The claw member is integrally formed with the movable member. A permanent magnet 25 has magnetic pole plates 26 and 27 facing each other, and a spacer 28 is adhered to each of them.

The iron core 21 is placed in the magnetic field formed by the magnetic pole plates 26 and 27.
The tip of is coming. 29 is an electromagnetic coil arranged to encompass the iron core 21, and when energized, the iron core 2
1 is excited.

30 beam set lever.

With the above-described configuration, the movable member 20 has two magnetically stable states: the first case in which the iron core 21 is attracted to the magnetic pole plate 26 by the action of the permanent magnet 25, and the second case in which the iron core 21 is attracted to the magnetic pole plate 27. Get position. Next, the operation will be explained.

First, as the drive shaft 4 rotates, the type wheel rotates. When the desired type 2 on the type wheel 1 rotates to a predetermined position, the electromagnetic coil 29 is energized in synchronization with this rotation. As a result, the iron core 21
Polarity appears at the tip of the iron core 21, and if this polarity is N pole in FIG. As a result, a suction force is generated. All of these forces turn the movable member 20 counterclockwise, and the selection pawl 22 engages the ratchet 3 and locks the type wheel 1. A similar operation is performed for each digit of the type wheels arranged side by side, and after one line of desired type is aligned at the printing position, printing can be performed on the printing paper 16 by pressing the platen 14 against the line of type. On the other hand, the arm 23 of the movable member 20 enters into the locus 31 of the set lever 30 due to the above selection operation. However, when the set lever 30 is rotated in the direction of the arrow E after printing is completed, the arm 23 receives clockwise torque and the movable member 20 is restored to its state before energization. FIG. 3 is a graph of the force F acting on the tip of the iron core 21 in the content explained in FIG. 3rd-
Figure a shows the state in which the tip of the iron core 21 is displaced from G1 to G2, and Figure 3-b shows the displacement of the force acting on the tip with this displacement, where the vertical axis is force F and the horizontal axis is The moving distance X is marked on the scale. A curve 32 shows the force F when the electromagnetic coil 29 is not energized. First, the iron core 21 is connected to the magnetic pole plate 2.
When it is on the 6 side, that is, X=X, it is attracted and held by the force of (-)F, and when it is on the magnetic pole plate 27 side, that is, X1
At the time of , it is attracted and held by the force of (+)F2. When it is on the magnetic pole plate 26 side, parts such as the spring member 13 shown in FIG. 1 are not required to hold the iron core 21 in a standby state. Magnetic pole plate 2
When the iron core 21 is on the 7 side, the iron core 21 that has been activated will maintain the selected state even if the electricity is cut off, so the leaf spring 7 as shown in FIG.
This means that it is not necessary. The curve 33 in Fig. 3-b shows the force F generated when energizing, and the moving distance
When =X1, the force of (-)f1 is canceled and (+)F3
At the end, the force of (+)F2 is superimposed on the force of (+)F
4 forces are generated. The force appearing in this curve 33 is the iron core 2
1 from the standby state, and the selection claw 22 moves to the ratchet 3.
F works until it is locked, but even if the electromagnetic coil is de-energized, the F
The selected state is maintained by the power of 2. Nt in FIG. 3-b indicates the neutral point of the iron core 21 when no current is applied, and is a location where no force is generated on either side. When resetting the movable member 20, by tilting it slightly to the left of this neutral point Nt, the magnetic pole plate 2 is moved by the magnetic field.
6 is attracted. Due to this self-resetting force, the dimensional accuracy of the resetting parts can be roughly achieved, and it also has favorable characteristics in terms of durability. FIG. 4 is a diagram of a character selection electromagnetic mechanism according to the present invention, and FIG. 4-a shows a cross-sectional view, and FIG. 4-b shows a plan view, in which a movable member 40, a permanent magnet 45,
An electromagnetic device unit L (hereinafter abbreviated as unit L) is composed of the magnetic pole plates 46, 47 and the electromagnetic coil 49 as basic components, and includes a movable member 50, a permanent magnet 55, and a magnetic pole plate 5.
6, 57, and the electromagnetic coil 59 constitute an electromagnetic device unit R (hereinafter abbreviated as unit R). Units R and L are installed side by side with the same pole facing away from each other (S pole in the figure). Fig. 4-a is a sectional view of Fig. 4-b taken along the plane dd' in the direction of arrow H. The movable member 40 has an iron core 41
and 42, one included in the electromagnetic coil 49 and the other placed outside the electrode coil.

The tip of the iron core 41 is placed in the magnetic field of the unit L formed by the permanent magnet 45 and the magnetic pole plates 46, 47, and performs the operation described in FIG. The tip of the iron core 42 is placed on the side of the other attached unit R, but the permanent magnet 55
The magnetic pole plates 56 and 57 are arranged so as to be almost unaffected by the magnetic force generated by the magnetic pole plates 56 and 57. On the other hand, the iron cores 51 and 52 on the side of the unit R are also arranged in the same manner, although their directions are different, and the two types of movable members are arranged alternately.

When the number of digits is large or the pitch between digits must be small, it becomes necessary to arrange multiple rows of electromagnetic coils in this way. However, if an electromagnetic device unit is simply provided, disadvantages arise. The details are explained below. FIG. 5 shows the movable member 40 in FIG. 4 in the same way as shown in FIG.
FIG. 5 is a diagram showing the correlation between the force F2 that the tip of the movable member 50 receives and the position Y of the tip.

FIG. 6 is a characteristic diagram of a state in which the electromagnetic coils 49 and 59 are not energized. In FIG. 5, as in FIG. 3, the force to the right in the drawing is represented by a 10 sign, the vertical axis is scaled with force F2, and the horizontal axis is the iron core 41,
51 is marked on the scale, Y is on the magnetic pole plate 46, and Y2 is on the magnetic pole plate 46.
is attached to the magnetic pole plate 47, Y3 is attached to the magnetic pole plate 56, and Y4 is attached to the magnetic pole plate 5.
7 shows the positions where they are each sucked and held. First, curves 61 and 62 drawn as solid lines show the characteristics when there is no magnetic member 58 inserted between unit R and unit L in FIG.

What can be seen from these curves is that their respective magnetic neutral positions are significantly shifted from the center.
That is, the neutral point Nll of the unit L is originally the magnetic pole plate 46,
The neutral point N12 of the unit R, which should be at the center of the magnetic pole plate 57, is shifted toward the magnetic pole plate 46. This not only causes a difference in the initial attraction force in the standby state, but also causes a decisive difference in the operating voltage between unit R and unit L, and in unit L, the initial attraction force in the standby state becomes smaller. Therefore, if the unit R is energized at any time, some of the movable members 40 of the unit L will also be guided and protrude, resulting in an inconvenience. It has been found that inserting the magnetic member 58 between the units L and R has the greatest effect in eliminating these problems. Curves 63 and 64 in FIG. 5 are characteristic curves when the magnetic member 58 is arranged, and the neutral point Nl] moves to Nl3, the neutral points Nl and Nl move to Nl4, and the This shows that each neutral point can be moved to the center of the opposing magnetic pole plates, and the suction force during standby can also be set to the same level.

Therefore, the operating characteristics of unit R and unit L can also be made the same, which significantly increases the reliability of the printer as a whole. It was also confirmed that the voltage at which erroneous printing occurs is increased due to induction, and the range of stable operating voltage as a whole is significantly expanded.

In Figure 4, unit L and unit R are installed side by side with the same polarity behind them, but the closer the units are, the more difficult it is to form a magnetic field in the space between the magnetic pole plates unless they have the same polarity. It's for a reason.

The occurrence of the above-mentioned induction-induced malfunction is also related to the arrangement of units R and L. The magnetic flux generated when the unit R is energized wraps around the iron core 41 from the space and magnetizes the tip. Since the magnetized pole at this time becomes the north pole, a force is generated that tends to separate the iron core 41 from the magnetic pole plate 46. As is clear from FIG. 5, if there is no magnetic member 58, the force F2 on the unit L side when it is on standby is the value F5 when Y=Y, and this means that the force F2 on the unit R side is It can be seen that it is smaller than F6 and also compared to curve 63, making it very easy to operate. Curve 63 improves this point, but it is not perfect. The iron cores 42 and 52 are installed to improve this point and prevent malfunctions due to induction. That is, when the unit R is energized, the magnetic flux generated in the iron core 51 passes through 52 and wraps around the magnetic pole plates 46 and 47, creating a state in which the magnetic flux does not wrap around (does not easily enter) the adjacent iron core 41. Because you can. The same applies when unit L is energized. Further, as can be seen from the above description, the selection pawl shaft 44 is preferably made of a non-magnetic material, and the same applies to the set lever. FIG. 6 is a schematic diagram showing the structure of a printer embodying an embodiment of the character selection electromagnetic mechanism according to the present invention shown in FIG. Components that are the same as those in FIG. 4 are designated by the same numbers, and their explanations will be omitted. 65 is printing paper, 66
67 is an ink ribbon, 67 is a platen roller, 68 is a type wheel, 69 is a ratchet formed on the type wheel 68, 70 is a type wheel shaft, 71 is a set lever, and 72 is a gear.

The operation of the printer will be explained below.

When the printer starts operating, the type wheel shaft 70 rotates in the direction of arrow K, and the type wheel 68 frictionally engaged with the type wheel shaft also rotates at the same time.When the desired type appears at the printing position, the electromagnetic coil 49, Or 59 is energized,
The movable member 40 or 50 operates, and the electromagnetic coil 59
When energized, the claw portion 53 of the movable member 50 jumps into the ratchet 69 and the type ring 68 is locked. When all the digits have been operated in this manner, the character selection process is completed. After the selection process, when the desired type is aligned at the printing position, the platen roller 67 is pressed against the type wheel 68 via the printing paper 65 and ink ribbon 66, and the printing process is completed.

Next, the printer goes into the printer setup process. The gear 72 is a gear that rotates once per printing stroke, and rotates in the direction of arrow M. A cam 73 provided on the gear 72 rotates the reset lever 71 in the direction of arrow L. At this time, the movable member 50 or 4
0 returns to the original standby state, and the type wheel 68 is also returned to the standby state by another gear, and all printing processes are completed. The electromagnetic coils 49, 59 are arranged in a staggered manner as shown in FIG. 4, which is an effective method for reducing the inter-digit pitch P.

As explained above, the character selection electromagnetic mechanism according to the present invention is superior to the conventional one in the following points.

(1) The use of permanent magnets eliminates the need for spring members and their mounting parts, as well as their assembly and adjustment man-hours, which is very advantageous in terms of cost.

(2) By using a permanent magnet, the synergistic effect with the electromagnetic coil, that is, the repulsive force and attractive force can be effectively used, so power consumption can be significantly reduced.

(3) Unnecessary frictional parts are eliminated by reducing the number of spring members and the like, resulting in a character selection electromagnetic mechanism that is extremely reliable in terms of operation and durability.

Next, another embodiment of the present invention will be described with reference to FIG.

Permanent magnets 75 and 85 are arranged next to each other with the same poles facing each other as explained in FIG. 4, and each has magnetic pole plates 76, 77, 86, and 87.

The magnetic member 58 in FIG. 4 is integrally formed with the magnetic pole plate 77. 79, 89 are electromagnetic coils, 80, 90 are movable members, 81, 91 are respective iron cores of movable members 80, 90,
82 and 92 are claw portions of the movable members 80 and 90, respectively;
4 each indicates a type ring.

The character selection electromagnetic device shown in Fig. 7 has a structure for reducing the inertia of the movable member to speed up the operation time, reducing the two iron cores of the movable member shown in Fig. 4 to one, and stabilizing the operation. Therefore, a magnetic member 78 is arranged on the side surface of the electromagnetic coil group of one electromagnetic device unit. The operation is exactly the same as that shown in FIG. 4, and in the standby state, the movable members 80 and 90 are attracted and held by the magnetic pole plates 76 and 86, respectively, but when the desired type on the type wheel 84 comes to the printing position, The pawls 82 or 92 actuated by the electromagnetic coils 79 or 89 jump into the correspondingly formed ratchets 85 on the side of the type wheel to selectively lock the type, and the above operation is completed. Then the platen (
(not shown) is pressed to perform the printing process, after which the reset lever 88 rotates in the direction of the arrow 1, and the movable members 80, 9 that have been attracted to the magnetic pole plate 77 or 87
0 and returns to the original standby state.

The movable member 80 in FIG. 7 shows a standby state, and the movable member 90
indicates the selected state. The character selection electromagnetic device shown in FIG. 7 is characterized in that the operating time is shortened and the structure of the movable member is simple and easy to manufacture. As explained above, according to the present invention, the permanent magnets of the two sets of electromagnetic device units are arranged with the same polarity facing each other, and the magnetic member is arranged between the electrode device units, so that the magnetic characteristics of each digit can be adjusted. Variations in the iron core are suppressed, and the iron core operates uniformly.
The operating time of the iron core is short and the power consumption is low, which brings about other effects.

[Brief explanation of drawings]

Figure 1 is a side sectional view showing a conventional character selection electromagnetic mechanism.
is a type wheel, 5 is a selection claw, 7 is a leaf spring, 8 is an electromagnet, 14
is the platen. FIG. 2 is a schematic diagram of the electromagnetic device unit that is the basis of the present invention, and FIG. 3 is an explanatory diagram of the operation of FIG. 2, where 20 is a movable member, 21 is an iron core, 25 is a permanent magnet, and 29 is a magnetic pole plate, 29 is an electromagnetic coil, and 30 is a set lever. FIG. 4 is a diagram showing an embodiment of the present invention, FIG. 41a is a side sectional view, and FIG. 4-b is a plan view, 40 and 50 are movable members, 49 and 59 are electromagnetic coils, 45 and 55 indicate permanent magnets, respectively. FIG. 5 is an explanatory diagram of the operation of FIG. 4, and the horizontal axis is the movable members 40, 5.
The vertical axis indicates the iron cores 41, 5 of the movable members 40, 50.
The force acting on each part is marked on a scale. FIG. 6 is a schematic diagram showing the structure of a printer incorporating the character selection electromagnetic mechanism of the present invention, in which 65 is printing paper, 68 is a type wheel,
40, 50 are movable members, 45, 55 are permanent magnets, 49,
Reference numeral 59 indicates an electromagnetic coil, 71 a beam set lever, and 73 a cam.

Claims (1)

[Claims] 1. A mechanism for selecting desired type on a type wheel,
A magnet comprising: a claw member that selectively engages the type wheel; a movable member having an iron core that operates the claw member; and a permanent magnet that provides two positional stability points, first and second, to the movable member. and an electromagnetic coil for actuating the movable member from a first position to a second position under the magnetic action of the magnetic means.
A character selection electromagnetic mechanism for a printer, characterized in that the same polarity of the permanent magnets of the electromagnetic device units arranged side by side are placed back to back, and a magnetic member is arranged between the electromagnetic device units.