JPS5845355B2 - 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.

An object of the present invention is to obtain a character selection electromagnetic mechanism that is easy to assemble and operates reliably.

Another object of the present invention is to obtain a character selection electromagnetic mechanism that has a short operating time and low power consumption.A still further object of the present invention is to prevent the selection claw from bouncing;
It is an object of the present invention to provide a printer with improved reliability of operation and a simple reset mechanism.

FIG. 1 is a schematic diagram showing a conventional actual case of a character selection electromagnetic mechanism for a printer using a type wheel.

Reference numeral 1 denotes a type wheel, which is frictionally coupled or spring-coupled with a spring or the like to the drive shaft 4, and rotates in the direction of arrow A as the drive shaft 4 rotates.

Characters, symbols, etc. are arranged around the type ring 1,
When the desired type 2 appears at the printing position, in synchronization with this, the electromagnet 8 is energized, the suction plate 11 is activated, and the actuating plate 12, which had previously locked the selection claw 5, is also activated in the direction of arrow B.

Therefore, the selection pawl 5 is moved to the selection pawl shaft 6 by the action of the plate spring 7.
, and engages with the ratchet 3 of the type wheel 1 to lock the type wheel 1.

The locked type wheel 1 stops as it is, but the type wheels and drive shafts 4 that have not yet been selected continue to rotate.

When character selection for each digit is completed in this way, the platen roller 1
4 is pressed against the type 2 via the ink ribbon 15 and printing paper 16, and the printing process is completed.

After printing, the selection claw 5 is reset by rotating the reset lever 17 in the direction of the arrow.

The above is the general operation of the conventional character selection electromagnetic mechanism.
As shown in FIG. 1, in order to operate the selection claw 5, the electromagnet 8 must be composed of an iron core 9, a yoke 10, a suction plate 11, an actuation plate 12, a restoring spring 13 for the actuation plate 12, etc. It had to be structurally complex.

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 is necessary to overcome the frictional load between the selection pawl 5 and the actuating plate 12 due to the plate spring 7 and the spring load of the compression spring 13.

This also caused an increase in power consumption,
This was also a factor in lengthening the operating time.

The present invention eliminates various drawbacks seen in the prior art and will be described in detail below.

FIG. 2 is a diagram showing one of the simplest embodiments of the electromagnetic device unit according to the present invention.

Fig. 2-a is a schematic diagram showing the entire character selection mechanism of the printer including the type wheel 1, and Fig. 2-b is a schematic diagram showing the magnetic means part of the electromagnetic device unit described above in a perspective view. be.

Reference numeral 20 denotes a movable member, which is composed of an iron core 21, a selection claw 22, and an arm 23, and is inserted so as to be rotatable around a selection claw shaft 24.

A permanent magnet 25 has magnetic pole plates 26 and 27 facing each other.

A spacer 28 is bonded to the magnetic pole plate 26, and the second-b
As shown in the figure, the magnetic pole plate 27 has a comb-shaped notch 3.
It has 2.

The iron core 21 is placed in the magnetic field formed by the magnetic pole plates 26 and 27.
The tip of the is being cast.

Reference numeral 29 denotes an electromagnetic coil arranged to encompass the iron core 21, and excites the iron core 21 when energized.

30 is a reset lever.

With the above-described configuration, the movable member 20 has two stable positions: the first case where the iron core 21 is attracted to the magnetic pole plate 26 by the action of the permanent magnet 25, and the second case where the iron core 21 is attracted to the magnetic pole plate 27. are doing.

The magnetic pole plate 27 does not come into direct contact with the iron core 21 but is inserted into the notch 32 to attract it, so it has the advantage that the attraction force does not increase significantly and can be kept below a certain value. ing.

Next, the operation will be explained.

First, as the drive shaft 4 rotates, the type wheel 1 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, polarity appears at the tip of the iron core 21, and if this polarity is N4t in FIG.
Since the polarity is the same as that of the magnetic pole plate 27, a repulsive force is generated, and because the polarity is different from that of the magnetic pole plate 27, an attractive force is generated.

All of these forces turn the movable member 20 counterclockwise, and the selection pawl 22 engages with the ratchet 3 to lock 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 arranged at the printing position, printing can be performed on the printing paper 16 by pressing the platen roller 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 reset lever 30 by the above selection operation.

However, when the reset 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 the state before energization. The figure is a graph of the force F acting on the tip of the iron core 21 among the contents described above.

Figure 3-a shows the state in which the tip of the iron core 21 is displaced from 01 to 02, and Figure 3-b shows the displacement of the force acting on the tip with this displacement, and the vertical axis shows the force. The scale indicates the position X moved on the F1 horizontal axis.

The curve 33 represents the force F when the electromagnetic coil 29 is not energized.
shows.

When the iron core 21 is on the magnetic pole plate 26 side, that is, when X = X1, it is attracted and held by the force of Hf1, and when it is on the magnetic pole plate 27 side, that is, when X = Ru.

In the following text, fl and initial attraction force f2 will be referred to as selective holding force.

When it is on the magnetic pole plate 26 side, parts such as the spring member 13 shown in FIG. This means that the leaf spring 7 as shown in FIG. 1 is unnecessary because the core maintains its selected state even when the current is turned off.

The curve 34 in Fig. 3-b shows the force F generated during energization, and when the moving distance is X-X1, the initial absorbing force Hf1 in the stationary state is canceled out (-)) When the force X=X2, (1) a force f4 is generated.

The force represented by the curve 34 separates the iron core 21 from the standby state and acts until the selection pawl 22 locks the ratchet 3, but even if the electromagnetic coil is de-energized, the selection holding force f2 continues to maintain the selected state.

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 to the standby state, the movable member 20 is tilted slightly to the left of the neutral point Nt so that it is attracted to the magnetic pole plate 26 by magnetic force.

Due to this self-resetting force, the dimensional accuracy of the reset system parts can be roughly maintained, and it also has favorable characteristics in terms of durability.

Figure 4 is a diagram of the character selection electromagnetic mechanism according to the present invention, and Figure 4-a
The figure shows a cross-sectional view, and the figure 4-b shows a plan view,
The electromagnetic device UNITSU IL (hereinafter abbreviated as UNITSU IL) is composed of the movable member 40, the permanent magnet 45, the magnetic pole plates 46, 47, and the electromagnetic coil 49 as basic components, and the movable member 60, the permanent magnet 55, magnetic pole plates 56, 57, and electromagnetic coil 59 to form an electromagnetic device unit R (hereinafter referred to as unit R).
).

Units R and L are installed side by side with the same pole facing back (S pole in the figure).

Fig. 4-a is a sectional view of Fig. 4-b taken along the plane d-d' in the direction of arrow H.

37 and 38 are comb-shaped notches similar to 32 in FIG.

The movable member 40 has iron cores 41 and 42, one of which is included in the electromagnetic coil 49 and the other placed outside of the electromagnetic coil 49.

43.53 is a selection claw formed integrally with the movable member 40.50.

A selection pawl shaft 44 is provided in common to the movable members 40 and 50.

The tip of the iron core 41 is placed in the magnetic field of the unit t-L formed by the permanent magnet 45 and the magnetic pole plates 46, 47, and performs the operation described in FIG.

The iron core 42 is provided auxiliary to effectively convert the magnetic flux excited by the electromagnetic coil into magnetic force, and its tip is placed on the side of the other unit l-R installed side by side, but the permanent magnet 55 and the magnetic pole plates 56 and 57 so as not to be influenced much by the magnetic field formed by the magnetic pole plates 56 and 57.

On the other hand, the movable member 50 on the unit I-R side has iron cores 41 and 4, although the directions are different, with the iron core 51 being included in the electromagnetic coil 59 and the iron core 52 being placed on the unit L side.
It has the same arrangement as No. 2, and the two types of movable members are arranged alternately.

When the number of digits to be printed is large or when the pitch between digits must be small, it becomes necessary to arrange multiple rows of electromagnetic coils in this manner.

However, if you simply add an electromagnetic coil, there will be some inconveniences that you must be careful about.

The present invention also provides an effective method for eliminating the disadvantages associated with miniaturization, and will be described in detail below.

FIG. 5 is an operation explanatory diagram similar to that shown in FIG.
It is a figure which shows the correlation between the force F2 which the front-end|tip of the movable member 40 and the movable member 50 receives, and the position y of a front-end|tip in a figure.

This is a characteristic diagram of a state in which the electromagnetic coils 49 and 59 are not energized, that is, in a stationary state, and as in FIG. 3, the force in the right direction (selection side direction) in the drawing is shown as a (+) sign, and F2 is the scale on the vertical axis.
The positions of the iron cores 41 and 51 are scaled on the horizontal axis.

yl is attached to the magnetic pole plate 46, and F3 is attached to the magnetic pole plate 56 with iron cores 41, 5.
1 indicates the suction-held position, F2. F4 is when the movable member is in the selected state, that is, the iron cores 41, 5
1 indicates the position where it is held between the notches, and the position is determined by the bottom of the ratchet of the type wheel.

First, curves 61 and 62 drawn as solid lines show the characteristics when the magnetic member 58 inserted between the units 1-L and the unit R in FIG. 4 is not present.

The following points can be seen from these curves.

(2) The neutral points of units L-L and R are out of balance.

2. There is a significant difference in the initial suction force and selection holding force between unit L and unit R in the standby state.

(For example, f, < F6) 3. Differences occur not only in the static state but also in the operating characteristics.

4. The main difference in operating characteristics is that the movable member is 40° 50°
These include the minimum operating voltage of the printer and the difference in flight time until it hits the type wheel.

In order to eliminate the above-mentioned defects, unit R
The simplest method is to insert the magnetic member 58 between the unit L and the unit L.

The characteristic curves when the magnetic member 58 is inserted are 63 and 64, the neutral point N11 moves to N13 and N12 moves to N14, respectively, and the characteristics of units L and R are made uniform.

Not only is the difference in the static state eliminated, but the operating characteristics are also made uniform, so the operating voltage of the entire character selection electromagnetic mechanism can be lowered and reliability can be significantly improved.

It can be seen that the selection retention force f7tf8 of curves 63 and 64 tends to be saturated as it approaches the selection side magnetic pole plates 47, 57.

This also applies to the notch 32 in Fig. 2 on the magnetic pole plate 47°57.
This is because, similarly to the above, since the notches 37 and 38 are provided, it is possible to prevent the selective holding force from increasing rapidly as it approaches the magnetic pole plate.

By doing so, it is possible to provide a mechanism for releasing the selected state and to simplify the structure.

Further, since the position when the claw portions 43, 53 of the movable member 40° 50 engage with the type wheel 1 is determined by the tooth bottom of the ratchet 3 of the type wheel 1, the printing position can be accurately set. The problem of the movable member once engaged bouncing and jumping out of the ratchet 3 due to the force of the collision is eliminated, further increasing reliability.

The notches 37 and 38 do not necessarily have to be comb-shaped, and the same effect can be achieved by cutting them in the shape of holes.

Further, by providing similar notches in the magnetic pole plates 46 and 56 on the standby side, it is also possible to omit the spacers 35 and 36 on the standby side.

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 FIGS. 2 and 4 are designated by the same numbers, and their explanations will be omitted.

71 is a reset lever, 72 is a gear, and 73 is a gum.

The operation of the printer will be explained below.

When the printer starts operating in response to a print command, the type wheel spindle 4
rotates in the direction of the arrow, and the type wheel 1 frictionally engaged with the type wheel shaft 4 also rotates at the same time, but when the desired type appears at the printing position, the electromagnetic coil 49 or 59
When the movable member 40 or 50 is energized and the electromagnetic coil 59 is energized, the claw portion 53 of the movable member 50 jumps into the ratchet 3 and the type wheel 1 is locked.

When all digits are selected in this way, the character selection process ends.

After the selection process, when the desired type is aligned at the printing position, the platen roller 14 is pressed against the type wheel 1 via the printing paper 16 and ink ribbon 15, and the printing process is completed.

The printer then enters a reset process.

The gear 72 is a gear that rotates once per printing stroke, and rotates in the direction of arrow M.

The reset lever 71 is activated by a cam 73 provided on the gear 72.
rotates in the direction of arrow Q.

At this time, the movable member 40 or 50 returns to its original standby state 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 pitch P between girders.

A problem with the assembly is the positional accuracy of the type wheel 1 and the electromagnetic coil that are arranged side by side, but positioning can be easily achieved by using the above-mentioned notch 38.

That is, by providing a protrusion 70 on a part of the coil bobbin 69 of the electromagnetic coil and guiding it through the notch 38, it is possible to easily position the electromagnetic coil.

Although the present invention has been described above with reference to several embodiments, the present invention is not limited to the above embodiments, and may be modified in many other embodiments depending on the shape of the iron core, the position of the permanent magnet and the magnetic pole plate, the position of the electromagnetic coil, etc. It becomes possible.

As described above, according to the present invention, the number of parts can be reduced, assembly is easy, and it is extremely advantageous in terms of cost.

Furthermore, by using the magnetic energy of the permanent magnet, electric power can be reduced, and the cost of the power source for driving the permanent magnet can also be reduced, which has a remarkable effect.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a conventional character selection mechanism, in which 1 is a type ring, 5 is a selection pawl, 7 is a leaf spring, 8 is an electrode stone, and 14 is a platen roller. FIG. 2 shows a schematic diagram of the electromagnetic device unit according to the invention;
Each figure shows an explanatory view of the operation in FIG. 2, where 20 is a movable member, 21 is an iron core, 25 is a permanent magnet, 26, 27 is a magnetic pole plate, 29 is an electromagnetic coil, 30 is a reset lever, and 32 is a magnetic pole plate 27. This is the notch provided in the. FIG. 4 is a diagram showing an embodiment of the present invention, in which FIG. 4a is a side sectional view and FIG. 4-b is a plan view, 40.50 is a movable member, 49.59 is an electromagnetic coil, 45. 55 is a permanent magnet,
37.3B each indicates a notch. Figure 5 is an explanatory diagram of the operation of Figure 4, and the horizontal axis is the movable member 40.5.
0 position, the vertical axis is the iron core 41.5 of the movable members 40, 50
Each scale represents the force acting on 1. FIG. 6 is a schematic diagram showing the structure of a printer incorporating the character selection electromagnetic mechanism of the present invention, in which 69 represents a coil bobbin, 71 represents a reset lever, and 73 represents a cam.

Claims (1)

[Claims] 1. In a printer that selects desired characters on a type wheel and prints them all at once using a platen or the like, a movable member that includes a pawl member that selectively locks the type wheel and an iron core and that operates the pawl member. and magnetic means comprising a permanent magnet and a magnetic pole plate for providing two stable positions, first and second, to the movable member; An electromagnetic device unit is constituted by an electromagnetic coil operated from a first position to a second position, the magnetic pole plates are arranged facing each other via the permanent magnet, and a comb-shaped A character selection electromagnetic mechanism for a printer, characterized by having a notch.