JPS5849394B2 - Dot printer printing drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dot printer in which a plurality of printing units arranged adjacent to each other are shaped so that an electromagnetic coil is excited to drive a lever, and the lever moves a dot pin. It relates to a print drive device for a dot printer that drives printing.

In recent years, for example, bankbook printers used in financial equipment are required to have high print quality, high speed printing, and miniaturization.

For this purpose, the movable parts of the print head, such as the dot pins and levers mentioned above, are shortened, the number of print units is increased, and the electromagnetic coils are closely spaced.

When the electromagnetic coils are placed in close contact with each other in this way, mutual interference between the electromagnetic coils is severe, which affects the quality of printing and printing speed.

For example, as shown in Fig. 1, electromagnetic coils M1, M2
, M3, when a current is applied to the central electromagnetic coil M2 to drive printing, the magnetic flux generated from this electromagnetic coil M2 leaks to the left and right adjacent electromagnetic coils M1 and M3, and the magnetic force of the central electromagnetic coil M2 increases. The magnetic force becomes weak, the set magnetic force cannot be obtained, the print density becomes thin, and clear print cannot be obtained.

Also, since the suction power is weak, the printing speed is also slower.

Furthermore, as shown in FIG. 2, among the electromagnetic coils M4 to M8, when a current is simultaneously applied to the central electromagnetic coils M5, M6, and M7 to drive printing, the central electromagnetic coil M6
Since the magnetic flux is repelled by the magnetic flux of the left and right electromagnetic coils M5 and M7 and does not leak, the set magnetic force can be obtained and printing can be performed with a predetermined printing pressure.
S, M7 is the electromagnetic coil M4 that does not apply this outer current.
, M8, the magnetic force becomes weaker, and the print becomes thinner as in the previous example.

Such a drawback occurs when the number of dots driven at one time is small, that is, when the number of dots is driven at one time, for example, the letter N as shown in FIG. 3, the sloped portion becomes thinner and the print becomes unclear.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a print drive device for a dot printer that can solve the above-mentioned drawbacks.

According to the present invention, when a current is passed through an electromagnetic coil corresponding to a dot pin to be driven for printing, the current is less than when the dot pin is driven for printing through an electromagnetic coil that is placed adjacent to this electromagnetic coil and is not driven for printing. Since we have installed a control circuit that allows current to flow, a weak magnetic flux is generated in this electromagnetic coil that does not drive printing, and this magnetic flux and the magnetic flux of the electromagnetic coil that drives printing repel, thereby preventing magnetic flux leakage from the electromagnetic coil that drives printing. Printing can be performed using the magnetic force that is set, and clear printing can be obtained.

Furthermore, since the suction force becomes stronger, the printing speed also increases accordingly.

That is, as shown in FIG. 4, when driving the electromagnetic coil M2 for printing, by applying a current to the left and right adjacent electromagnetic coils Ml, M3 to an extent that does not drive the dot pin, these electromagnetic coils M1, M3 A magnetic flux weaker than that of the electromagnetic coil M2 is generated, and this magnetic flux and the electromagnetic coil M
It is possible to prevent the magnetic flux of the electromagnetic coil M2 from repelling each other and leaking the magnetic flux of the electromagnetic coil M2.

As a result, the electromagnetic coil M2 can obtain a set magnetic force, and thereby, when the number of dots to be driven at once is small, a predetermined printing pressure can be obtained for, for example, the inclined part of a character.
As shown in FIG. 5, the same printing pressure can be obtained in the sloped part of the letter N as in the straight part with a large number of dots, and clear printing can be achieved.

Therefore, according to the present invention, it is possible to print katakana, numbers, and even kanji characters that have many sloped portions or arcuate portions very clearly.

Moreover, in this invention, there is no need to flow a larger current to compensate for the decrease in the magnetic force of the electromagnetic coil for printing, so there is no increase in heat generation, and this makes the dot printer smaller, faster, and faster. This achieved high print quality.

An embodiment of the present invention having such characteristics will be described in detail below with reference to the drawings.

The drawing shows a dot printer, and in Figure 6, dot pins (also called wires), levers, electromagnetic coils, etc.
A set number of printing units 1 is a predetermined number (for example, 20 pieces)
are arranged closely in a circular shape, and the levers 2... of each printing unit 1... are gathered at the center, and these levers 2...
The dot pin is driven at the free end of...

Note that 3 is a substrate, and terminals for driving and controlling each printing unit 1 are provided.

FIG. 7 shows one printing unit 1, in which a support 5 is fixed to the outer side of the upper surface of the bracket 4, and an iron core 6 is fixed to the inner side.

A cap 7 is fixed to the upper surface of the above-mentioned support column 5, and the inner surface of this cap 7 is hollow, and the lever 2 is attached to this.
is located, and the proximal end of the lever 2 is connected to the cap 7 by the pin 8.
It is pivoted to the A rule.

An electromagnetic coil 9 is wound around the aforementioned iron core 6, and an auxiliary coil 10 is wound around the support column 5.

Note that this auxiliary coil 10 may not be provided.

The upper end surface of the aforementioned iron core 6 faces the intermediate portion of the lever 2, and attracts the lever 2 when a current is passed through the electromagnetic coils 9, 10 and a magnetic force is generated.

The head 12 of the dot pin 11 is in contact with the lower surface of the tip of the lever 2, and a return spring 14 is interposed between the head 12 and the mounting frame 13.

As shown in FIG. 6, the printing units 1 configured in this manner are arranged closely in a circular shape, and each printing unit
The lower ends of the dot pins 11 are arranged in two vertical rows in a staggered manner, as shown in FIG.

FIG. 9 shows a control circuit for driving each electromagnetic coil 9, and the electromagnetic coils 9a to 9d are connected to the printing units 1a to 9d shown in FIG.
They are 1d coils and are adjacent to each other.

These electromagnetic coils 9a to 9d are supplied with current when the corresponding transistors 15a to 15d are turned on, and when this current is supplied for a set time width TI, a magnetic force that attracts the lever 2 is generated. It is provided.

Note that 16 in the figure is a resistor.

In order to turn on each of the transistors 15a to 15d, a print command signal is input to the corresponding input terminals a to d, and this signal is input through the corresponding OR game N8a to 18d to turn them on.

Note that the time width of the above-mentioned signal is set to be the same as the time width T1 of the current that causes the electromagnetic coil 9 to generate magnetic force.

Further, the above-mentioned print command signal is transmitted to each of the OR gates 18a to 18.
It is provided to be input to AND gates 17a to 17d provided in pairs with
A pathless signal from the oscillator 19 is input to a to 17d.

Further, the outputs of the AND gates 17a to 17d are provided to be input to the adjacent or games N8a to 18a on both sides.

As shown in FIG. 10, the pulse width of the oscillator 19 described above is set to a time width T2 in which a large number of pulses are generated with respect to the time width T1 of the print command signal.

For example, if a print command signal is input to the input terminal b, this signal is transmitted to the transistor 1 through the OR game N8b.
Turn on 5b.

For this purpose, a current with a duration T1 is supplied to the electromagnetic coil 9b, and a magnetic force is generated to attract the lever 2, and the printing unit 1b is driven to print.

Further, since the print command signal input to the input terminal b mentioned above is input to the AND gate 17b, the pulse signal from the oscillator 19 is input to the OR gates N8a and 18c on both sides, and the respective transistors 15a and 15c are activated by the pulse signal. Repeated OFF and ON operations are performed.

That is, with one pulse, transistors 15a and 15c
When turned on, magnetic flux is generated in the electromagnetic coils 9a and 9c.

However, since the supply current is small for one pulse, lever 2
It turns OFF before attracting the magnetic flux, and the generated magnetic flux tries to disappear.

Then, with the next pulse, magnetic flux is generated again while the previous magnetic flux has not disappeared due to the electromagnetic induction effect, that is, while there is residual magnetic flux, and as this operation is repeated in the pulse cycle, the electromagnetic coils (Ly9a, 9c) This means that a weak magnetic flux is generated continuously.

Since the weak magnetic flux generated from the electromagnetic coils 9a and 9c repels the magnetic flux of the central electromagnetic coil 9b, the magnetic flux of this electromagnetic coil 9b is prevented from leaking to the electromagnetic coils 9a and 9c on both sides, and the set Magnetic force can be obtained and the printing unit 1b can print clearly in the state described in FIG. 4.

FIG. 11 shows a second embodiment of a control circuit for driving each electromagnetic coil 9, and parts having the same functions as those in FIG. 9 are designated by the same reference numerals.

Each electromagnetic coil 9a to 9d has two corresponding transistors 15a-1 and 15a-2 to 15d.
-1, 15d-2 are turned on to supply current, but each of the two transistors 15a 1, 15a
-2 to 15a t, 15a - 2 have their respective load resistors 16a-1 to 16d-1 having small values and passing a large amount of current, and load resistors 16a-2 to 16d-2 having small values and passing a small amount of current (the above-mentioned many When each transistor 15a-1 to 15d-1 side is turned on, the electromagnetic coils 9a to 9d are provided to generate a magnetic force that attracts the lever 2, and the other side When the respective transistors 15a-215d-2 are turned on, the electromagnetic coils 9a to 9d are provided so as to generate magnetic flux to the extent that the lever 2 is not attracted.

Turn on each transistor 15a-1 to 15d-1
In order to do this, a print command signal is input to the corresponding input terminal a=d, and this signal is input via the amplifiers 20a to 20d to turn on.

Further, the signals inputted to each input terminal a=d described above are provided so as to be inputted to OR gates 21a to 21d provided corresponding to the adjacent magnetic coils 9a to 9d on both sides, and these OR gates The gates 21a-21d are connected to AND gates 22a-22d.

The above-mentioned AND gates 22a to 22d are provided so as to be inhibited by signals from the corresponding input terminals a to d, respectively.

For example, if a print command signal is input to input terminal b, this signal is transmitted to transistor 15b via amplifier 20b.
Turn on -1.

Therefore, a current with a duration T1 is supplied to the electromagnetic coil 9b, and since the resistance value of the load resistor 16b-1 is small, a magnetic force that attracts the lever 2 is generated in the electromagnetic coil 9b, and the printing unit 1b prints. Driven.

Furthermore, the print command signal input to the input terminal b described above is input to the adjacent OR gates 21a and 21c on both sides, and since no signal is input to these input terminals a and c, the AND gates 22a and 22c Since the inhibition is lifted, outputs are generated from the AND gates 22a and 22c, and the respective transistors 15a 2 and 15c 2 are turned on.
be done.

These transistors 15a-2, 15c-
2 is turned on, current is supplied to the electromagnetic coils 9a and 9c, but the load resistances 16a-2 and 16c
Since the resistance value -2 is a dog, a small amount of current flows, and although magnetic flux is generated in the electromagnetic coils 9a and 9c, it is not enough to attract the lever 2.

Since this magnetic flux and the magnetic flux of the central electromagnetic coil 9b repel, the magnetic flux of the electromagnetic coil 9b is prevented from leaking to the electromagnetic coils 9a and 9c on both sides, and a set magnetic force can be obtained. In the state explained in Figure 4,
The printing unit 1b can print clearly.

Figure 12 shows the third part of the control circuit that drives each electromagnetic coil 9.
An embodiment will be shown, and parts having the same functions as those in FIG. 9 will be described using the same reference numerals.

Each electromagnetic coil 9a to 9d is supplied with a current when the corresponding transistor 15a to 15d is turned on, and the magnetic force that attracts the lever 2 is generated by supplying this current for a set time width T1. It is set in.

Each of the transistors 15a to 15d described above is turned on by inputting a print command signal to the corresponding input terminals a''-d.

Each electromagnetic coil 9a to 9d and each transistor 15a to 15
d, there are resistors 16a-3 to 16d to reduce the current.
-3 through two diodes 23a-1, 23a-
2 to 23d-1, 23d-2 are connected in parallel, and these diodes 23a-1, 23a-2 to 23d-
1 and 23d2 are provided so that a current flows when each of the adjacent transistors 15a to 15d is turned on.

The aforementioned resistors 16a-3 to 16d-3 are set to a resistance value such that when a small current flows through the resistors 16a-3 to 16d-3 to the corresponding electromagnetic coils 9a to 9d, a magnetic flux is generated to the extent that the lever 2 is not attracted. .

For example, if a print command signal is input to input terminal b, this signal turns on transistor 15b.

Therefore, a current with a duration T1 flows through the electromagnetic coil 9b, and a magnetic force that attracts the lever 2 is generated in the electromagnetic coil 9b, so that the printing unit 1b is driven to print.

At the same time, when the above-mentioned transistor 15b is turned on, the diodes 23a-2 and 23c-1 on both sides become conductive, so a small current also flows through the corresponding electromagnetic coils 9a and 9c, and a weak magnetic flux is also generated in these. Occur.

Since this magnetic flux and the magnetic flux of the central electromagnetic coil 9b repel, the magnetic flux of the electromagnetic coil 9b is prevented from leaking to the electromagnetic coils 9a to 9c on both sides, and the set magnetic force can be obtained. In the state explained in FIG. 4, the printing unit 1b can print clearly.

In addition, in the first to third embodiments described above, the electromagnetic coil 9
A to 9d, that is, printing units 1a to 1d have been described above, but the drive control circuit is also constructed for the electromagnetic coils 9 of other printing units by connecting adjacent electromagnetic coils one after another in the same manner.

Further, the printing unit 1 may be arranged in a straight line, and the dot pins 11 may be arranged in a line.

According to experiments, as long as the current flowing through the non-printing electromagnetic coil is extremely small, the print density remains relatively weak;
It has been confirmed that when the above-mentioned current exceeds a certain value (however, this varies depending on the structure of the printer), the print density sharply increases, and thereafter, even if the above-mentioned current is further increased, the print density does not change much.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, FIGS. 1 and 2 are explanatory diagrams showing defects in the conventional electromagnetic coil arrangement, FIG. 3 is an explanatory diagram showing defective printing, and FIG. 4 is an explanatory diagram showing the magnetic flux according to the present invention. 5 is an explanatory diagram of good printing according to the present invention, FIG. 6 is a plan view of the don't printer, and FIG. 7 is a sectional view of the printing unit.
Figure 8 is a plan view showing the dot pin arrangement, Figure 9 is a block diagram of the electromagnetic coil drive control circuit, Figure 10 is a signal time chart, and Figure 11 is the electromagnetic coil drive control of the second embodiment. Circuit Block Diagram FIG. 12 is a block diagram of a drive control circuit for an electromagnetic coil according to a third embodiment. 9... Electromagnetic coil, 11... Dot pin, 15... Transistor, 16...
Resistor, 17, 22...And gate, 1B, 2
1...OR gate, 19...Oscillator, 23...Diode.

Claims (1)

[Claims] 1. In a dot printer in which multiple electromagnetic coils are arranged adjacent to each other to drive each dot pin, a current is passed through the electromagnetic coil corresponding to the dot pin to be driven for printing, and at the same time, a A print drive device for a dot printer equipped with a control circuit that allows a smaller current to flow through an electromagnetic coil that is not driven for printing than when driving a dot pin for printing.