JPS5849193B2 - Hammering control method in serial printers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hammering method in a serial printer.

A serial printer is a sequential type printing device that prints desired characters, symbols, etc. on various slips, bankbooks, etc.

For example, it has achieved high enough print quality and copying ability to print on unified slips, which are now rapidly becoming popular, and perform OCR processing.

In this case, printing speed is also an important element that a serial printer should have, and conventionally, serial printers have a type bar set and have achieved a printing speed of about 20 characters/second.

However, with the introduction of online processing by computers, the above printing speed was no longer sufficient, and in recent years, servo-type serial printers have been proposed and printing speeds of about 40 characters/second have been secured.

However, although the printing speed of 40 characters/second mentioned above is twice the printing speed of conventional printers, it does not reach the maximum printing speed that can be theoretically achieved in a servo serial printer. I haven't gotten it.

Now, in order to realize high-speed printing, it is necessary to comprehensively realize all kinds of improvements in the mechanisms and operations within the serial printer.

The present invention seeks to improve the hammer mechanism of the print head in particular.

That is, an object of the present invention is to provide a hammering method that can ensure a printing speed sufficiently higher than that which can be realized with existing serial printers.

In accordance with the above object, the present invention employs a servo-controllable DC motor in place of the conventional hammer magnet as a drive source for imparting hammer motion to the print head, and furthermore, the hammer stroke of the print head is a continuous first stroke. and a second stroke, such that the start point of the first stroke is a rest point of the hammer action and the end point of the second stroke is a point of impact on a platen supporting the print media, wherein the first stroke The end point of the second stroke, that is, the start point of the second stroke, is the temporary stable point, and when printing data is continuously supplied, the continuous hammer is set between the temporary stable point and the impact point, that is, the second stroke. The printing apparatus is characterized in that it performs a ring and returns to the starting point of the first stroke when the supply of print data stops.

FIG. 1 is a schematic structural diagram showing a part of a serial printer to which the present invention is applied.

In this figure, numeral 11 is a print medium on which desired characters are printed across several lines in a horizontal line, such as roll paper or a bankbook.

The print medium 11 is a mechanism (platen) that supports the print medium.
It is intermittently fed while being supported by 12.

The printing unit 13 impacts desired characters on the printing medium 11, and a total of 12 characters, 64 characters, are printed in two rows each on the top and bottom.
Print head 1 consisting of 8 characters arranged in a crown shape
3-1, a drive mechanism section 13-2 housing a type selection motor that rotationally drives the type selection motor and a hammer source that impacts one type toward the medium 11, and a ribbon cartridge 13- that stores a red and black ink ribbon. Consists of 3rd class.

The printing unit 13 rides on the moving shaft 14 and moves in the direction of arrow A in the figure to perform a spacing operation.

The moving shaft 14 is rotated by a space motor 15, and a helical groove is formed on the moving shaft 14, so that the printing unit 13 is spaced entirely by the feeding operation of the helical groove accompanying the rotation. Do the following.

Each time one horizontal line of printing is completed, the printer returns to the direction of arrow A' in the figure.

Further, although not shown, a control circuit board is provided on which a circuit for controlling the printing unit 13, the motor, the hammer drive source, etc. is mounted.

Of the various mechanisms schematically illustrated in FIG. 1, the present invention will be described with respect to print head 13-1 and the hammer drive source.

Conventionally, a hammer magnet has been used without exception as a hammer drive source for causing the print head 13-1 to hammer the print medium 11 supported by the platen 12, and in the hammering method using this hammer magnet, The hammer stroke from the rest point of the print head 13-1 to the impact point on the platen is usually n(mi
) is set.

When focusing on this hammer stroke, there is still room to increase the printing speed.

That is, the hammer stroke of n (mm) still includes room for reduction, and for example, this can be set to n1 (it).

However, for serial printers used as office machines in banks, for example, front inserts, inserter journals, etc. are prepared separately, and all printing media (passbooks) can be printed.
Therefore, it is not possible to simply shorten the hammer stroke to 01 (mm).

In other words, when using these front inserters, etc.
A member that guides the print medium is installed between the print head 13-1 and the platen 12, so when the hammer stroke is fixed at nt (''), the member guides the print head 1.
This is because there is a risk of being caught at 3-1.

Therefore, when inserting a print medium, etc., the hammer stroke must be set to n (mm) to prevent the print head 13-1 from getting caught in the above-mentioned member.

By the way, once the medium is guided to the printing position along the guide member, the guide member is retracted downward so as not to interfere with printing.

However, after the guide member is retracted, the distance between the print head and the platen can be set to n1 ('').

That is, before printing starts, the distance between the print head and the platen is a stroke length of 6 mm, but during printing, the stroke length can be set to n1 (mm) in order to realize high-speed printing.

In other words, the hammer stroke is 3mm.
(xi).

Now, if such a variable hammer stroke is realized using a conventional hammer magnet, the hammer speed will be increased, but
) It is necessary to provide two hammer magnets for the stroke, which is not only uneconomical but also increases the weight of the printing unit 13, resulting in slow space movement and no increase in printing speed.

Regarding hammer energy, due to the structure of the hammer magnet, a return spring must be attached, and hammering is performed against the return spring, so the hammer energy is not used effectively. This becomes a hindrance in increasing the printing speed.

Therefore, the present invention replaces the conventional hammer magnet so that the hammer stroke of n1 (mm) and n (mm) can be freely switched and that sufficient hammer energy is supplied for hammering. Adopts a servo-controllable DC motor.

Note that no example has yet been seen in which a DC motor is used as a hammer device in a printer.

FIG. 2 is an enlarged perspective view showing only a portion of the serial printer in FIG. 1 that is related to the present invention.

In FIG. 2, reference numeral 21 denotes a DC motor employed in accordance with the present invention, which hammers the print head 13-1 toward the platen 12 through a gear 22 in the directions of arrows S1 and S2.

Arrow S1 means a first stroke, and arrow S2 means a second stroke.

Specifically, the first stroke is n2 (mm), the second stroke is n1 (m7rL'), and the total is 11+n2 =
The hammer stroke is H (mm).

Next, the operation will be explained with reference to the graph in FIG.

In FIG. 3, the horizontal axis represents time t, and the vertical axis represents stroke amount S, respectively.

First, when a hammer command is supplied at t20, the print head 13-1 (FIG. 2) moves toward a temporary stable point, which is the end point of the first stroke, while being servo-controlled while maintaining the speed curve C1.

The position of this temporary stable point is shown as a dotted line P.

After this, the designated type 23 according to the supplied printing data
(Fig. 2) together with the print head 13-1 (Fig. 2),
It follows the speed curve C2 toward the impact point on the platen 12 (FIG. 2).

The position of this impact point is shown as a dotted line Q in FIG.

When the second print data is subsequently supplied, the print head 13-1 does not return to the starting point of the first stroke S1, but returns to the temporary stable point P while maintaining the speed curve C3 and being servo-controlled.

Therefore, the second printed character is hammered together with the print head 13-1 following the speed curve C4.

The hammer stroke at this time is the second stroke S2 and is n1 (mm).

If the second type is printed according to the conventional method, it will be hammered following the speed curve of the dashed-dotted line C/, and one hammer hour will be 13-11. - It is naturally longer than t1.

If the third print data is subsequently supplied, it will be hammered from the temporary stable point P toward the impact point Q in the same way.

In this way, since printing is performed by reciprocating only the second stroke S2, it is clear that printing can be performed faster than in the past.

In the graph of Figure 3, if the supply of print data is interrupted, it is assumed that a new print medium will be inserted next, so after the last print is completed, the print head 13
-1 is C,? While being servo-controlled while maintaining the speed curve of the print head 13-1, the rest point (first stroke S1
(starting point) to maintain the distance between the platen 12 and the print head 13-1 at the maximum n (7n1n).

This variable stroke hammering is possible only because a servo-controllable DC motor is used.

Further, since the return spring associated with the hammer magnet is not required, the hammer energy can be used effectively.

A specific example of a circuit that implements the two-stage switching hammering described above will be described.

FIG. 4A shows 1 to which the hammering method of the present invention is applied.
4B is a block diagram showing an example of the circuit, and FIG. 4B is a time chart for explaining the operation of the circuit of FIG. 4A.

In FIG. 4A, 21 is the DC moke M for the hammer shown in FIG. attached.

The output voltage vs of the potentiometer 41 is determined by the differential amplifier 42.
is input to one terminal of

On the other hand, the output voltage ■1 from the variable reference voltage generation circuit 43 is applied to the ten terminals, and the difference voltage VR-vs is applied via the phase compensation circuit 44, clamp circuit 45, switch 46 and current amplifier 47. A voltage is applied to the DC motor 21 .

Then, the DC motor 21 is servo-controlled so that the differential voltage vR-vs becomes zero.

Next, the operation of the circuit shown in FIG. 4A will be explained with reference to the time chart shown in FIG. 4B.

First, a printing finger 4>a is supplied from a central control device (not shown) at time T1 (see a in FIG. 4A and a in FIG. 4B).

As a result, the switch Sa of the variable reference voltage generation circuit 43
is closed, and the reference voltage vR of the circuit 43 is V.

It becomes 0. This reference voltage of R + r a R VCC・ is RaR in Figure 4B d)
Denoted as 10r2.

Due to the voltage difference between this VRa and the potentiometer 41,
During the period ta (see FIG. 4B, a), the current amplifier 47 is controlled to supply the drive current ■Ma (see FIG. 4B, f) to the DC motor 21.

In this case, the drive current ■Mai is supplied only in the first half of the period ta, and after a predetermined time has passed, the drive current ■Mai' (fourth
A braking current (see Fig. B f) is supplied.

In other words, when starting with the drive current set to positive Ma, the current changes to negative at an appropriate timing by servo control. Ma', the DC moke stably stops at the target position.

The DC motor 21 is servo-controlled by the above drive currents ■Mai and ■Mai', and accordingly, the output voltage ■s of the potentiometer 41 changes to the fourth B in the period ta.
It changes like vsa in figure e.

And this vsa is the reference voltage vRaR (1V.

.・) When it matches, the temporary stable point R0ra P (see Figure 4B e).

This temporary stable point P is the same as P in FIG.

Further, the change in vsa described above corresponds to the speed curve C1 in FIG.

In FIG. 4B f, ■Mai maintains a constant peak level, which is defined by the clamp circuit 45 of FIG. 4A.

Thereby, uniform acceleration of the DC motor 21 can be achieved.

'M a'i has a predetermined waveform that goes from negative to zero level, and this predetermined waveform is shaped by the phase compensation circuit 44.

In other words, the circuit 44 adds a velocity component obtained by differentiating the actual displacement position (corresponding to Vs) to achieve more stable servo control.

Next, at time T2 after the period ta, the impact finger 4>l) is supplied from the central controller (4th B
(see figure b).

As a result, the switch Sb of the variable reference voltage circuit 43 in FIG. 4A is closed, and the reference voltage vR in FIG. 4B becomes .

” R+ra/, rises to the level indicated by VRb of 5d.

As a result, the DC moke 21 is fully energized during period tb (see FIG. 4B) and causes the print head to fly toward the platen with high energy.

This state of flight is represented by a waveform eVsb in FIG. 4B, which corresponds to the speed curve C2 in FIG.

The drive current at this time is .multidot.Mbi (see FIG. 4B, f).

Furthermore, at time T3, an excitation stop signal C is supplied from the central controller (see FIG. 4B, C), and the switch 46
to open.

As a result, the drive current becomes ■Mci (see Fig. 4B, f), which has a current value of zero.

As a result, the period t.

During this period, the print head flies at a constant speed, collides with the platen at time T4, and printing is performed.

This uniform flight is a process inserted in order to obtain constant printing energy regardless of the thickness of the printing medium and to prevent ink shading from appearing.

After this, if print data continues to be supplied, the print head will move to the rest point O (01 in Figure 4B e, S=O in Figure 3).
It withdraws to the temporary resting point P without returning to the previous point.

This downward movement to point P is caused by the drive current IMO'l
It is stabilized at point P by the bank-to-bank control described above.

After further printing is repeated and a series of print data has been processed, neither the printing finger /+a nor the impact finger +b is supplied from the central control device, so the switch S shown in FIG. 4A is
a and Sb are both opened and vR becomes zero (V in Fig. 4B d)
(See R, O).

This causes the DC motor 21 to rotate in reverse until it reaches its rest point.

The output vs of the potentiometer 41 at this time is as shown by C5 in FIG. 4B e, which corresponds to C in FIG. 3.

As explained above, according to the present invention, in principle, 111 (
A high printing speed is ensured by maintaining an extremely short hammer stroke of mm''), and if necessary, the hammer stroke can be changed to n(m'IIL).
The hammering action of returning the hammer to the original position is achieved using a single hammer drive source (DC motor).

Furthermore, since the hammer energy is not reduced by a return spring or the like, it is also economical.

[Brief explanation of drawings]

1 is a schematic structural diagram showing a part of a serial printer to which the present invention is applied; FIG. 2 is an enlarged perspective view showing only a portion of the serial printer of FIG. 1 to which the present invention is applied; FIG. 3 is a graph for explaining the hammering method of the present invention, FIG. 4A is a block diagram showing an example of a circuit implementing the method of the present invention, and FIG. 4B is a time diagram showing waveforms of important parts in FIG. 4A. It is a chart. In the figure, 11 is a print medium, 12 is a platen, and 13-1
is a print head, 21 is a DC motor, 41 is a potentiometer, 42 is a differential amplifier, 43 is a variable reference voltage generator,
44 is a phase compensation circuit, 45 is a clamp circuit, 47 is a current amplifier, S1 is a first stroke, and S2 is a second stroke.

Claims (1)

[Claims] 1. In a hammering control system for a serial printer that has a print head formed by arranging a large number of printed characters, a hammer drive source that applies a hammer action to the print head, and a platen that supports a print medium, the hammer source is controlled by direct current. By using a motor and servo-controlling the DC moke, the print head can impact the platen through successive first and second strokes, and the print data specifying the type to be printed can be continuously printed. If the print data is supplied continuously, printing is performed by continuously hammering the print head only along the second stroke, and when the supply of print data is stopped, printing is performed via the second stroke and the first stroke. 1. A hammering control system for a serial printer, characterized in that the print head returns to a starting point of a first stroke, which is a rest point of the print head.