JPS59131486A - Ribbon drive system of printer - Google Patents

Abstract

PURPOSE:To exactly generate a torque toward the original turning direction of a step motor by exciting the stoppage phase by a drive current when driving the step motor from the stop state. CONSTITUTION:The time delay M of a delay circuit 25 is set at the same time as the time delay B of a delay circuit 14. After the lapse of the time delay M, signal N is generated from AND gate circuit 27. By the signal N, a clock generation circuit 18 starts to operate to generate a ribbon feed clock 0, and by the 4-pulse of the clock 0, the motor is turned to the next stop position. When driving the step motor from the stop state in this way, the stop phase excited by holding current is switched to be excited by a drive current, and then phase- excitation accompanying the next rotation is made.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a ribbon drive system for a printer that is equipped with a mechanism for feeding the ribbon from the ribbon supply side to the winding side, and drives the ribbon winding member by intermittent drive of a step motor. In particular, the step motor, which is loaded in the opposite direction when stopped, can be reliably rotated in the forward direction during the next drive, improving the reliability of motor operation and achieving high print quality. The present invention relates to a ribbon drive system for a printer that can be obtained.

In general, step motors are driven with a drive current only when they are driven, and are excited with a holding current that is smaller than the drive current when they are stopped, in order to prevent heat generation and other reasons. In this case, when driving the motor from a stopped state, the conventional driving method is to leave the holding current in the stopped phase as it is, and to rotate the motor by exciting it with the drive current from the next phase.

However, in cases such as in a ribbon feed motor, where the driven load, the film ribbon, exerts a force that tries to rotate the motor in the opposite direction, when the current is reduced to a holding current in a stopped state, the holding force is also reduced. There is a situation where the motor is returned in the opposite direction by the reversing force of the film ribbon, causing a change in the stop position.

FIG. 1 is a partially cutaway top view of a conventionally used film ribbon car i-ridge.

In the drawing, ■ is the cartridge body, 2 and 3 are the main body I
4 is a locking part where an unused film ribbon is stored, 5 is a rotating roller, 6 and 6A are film ribbons, 7 is a feed gear, 8 is a winding shaft, 9 is a heald, 10
11 is a tension lever, 12 is a spring member, ] 3 is a pack tension member storage area, 13A is a pack tension member, and arrow S indicates the position of the film ribbon 6. The feeding direction, arrows T and U, indicate the direction of movement of the belt 9.

The film ribbon 6 is fed from the ribbon core portion 4 shown on the right side in the direction of arrow S by the rotation of a feed gear 7 and a take-up shaft 8 driven by a step motor (not shown), and is sent to the take-up shaft 8. It is wound up one after another. In this case, the pack-tension member 13A is in contact with the core portion 4 from above, and the film ribbon 6 is moved in the direction of arrow S due to the frictional resistance, while applying pack tension. It's working.

Therefore, when the ribbon is fed intermittently in conjunction with the printing operation, back tension is applied to the film ribbon 6, and at the same time, the winding state of the ribbon in the core portion 4 is prevented from being disturbed.

Further, the feed gear 7 and the winding shaft 7 on the winding side are configured to have different diameters, and a belt 9 made of an elastic material such as rubber is provided between the gear 7 and the shaft 8.
is hung.

With this configuration, when winding the ribbon, tension is always applied to the film ribbon 6.6A, allowing tight winding. During normal winding, the belt 9 between a and b is in tension, and the belt 9 on the opposite side between a' and 57 is slack.

When the ribbon feeding operation is completed, the distance between a-b and a'-
The force that keeps the tension constant between belt 9 and 57 is
, the feed gear 7 is rotated in a direction opposite to the normal winding direction indicated by arrows T and U. That is, the step motor is returned to its stop position in the opposite direction.

Next, such reverse rotation at the stop position will be explained in detail using a torque curve of the step motor.

FIG. 2 shows the torque curve of the step motor during normal operation.

In this Fig. 2, the stop phase is φ4, and points Y and Z
and are at their respective stop positions. That is, due to the previous driving, the phases φ1 to φ4 are switched and stopped at the stop point Y, and then, by the four pulses of the ribbon feed clock, the phases φ1 to φ4 are similarly switched, and the stop point is reached. It shows that it will be stopped at 2.

And, as already explained, in general.

At the stop points Y and Z, drive/hold switching is also performed to prevent heat generation in the motor, circuits, etc., and to improve operational reliability.

FIG. 3 is a torque curve of the step motor when switching between drive and hold.

As shown in FIG. 3, the motor is at one stop position, for example, point Y, and in that stop state,
It is switched from VE to φ4 HOLD and held with relatively weak torque.

When the motor is in a detented state with such a relatively weak torque, if reverse rotational torque is applied from the driven load side such as the ribbon cartridge, as explained earlier, the motor will move toward the left in the drawing, that is, point X. You will be sent back in the direction of.

Assume that this reverse rotation torque and the bold torque of φ4 HOLD are in equilibrium at point X, and this position is the stop position of the motor.

In this state, normal drive operation is performed and drive phase φ1
As is clear from FIG. 3, the torque of φ1 at this point X is zero. Therefore, the motor is not rotated at full heat, or even if it moves slightly in either the forward or reverse direction, sufficient torque required for nine rotations cannot be obtained, and as a result, it is hardly rotated.

Next, when the phase is switched to φ2, it begins to rotate in the opposite direction, and when φ3 is selected, rotation in the forward direction is performed for the first time at this point, and normal rotation in the forward direction also occurs in the next φ4. can continue.

The torques φ1 to φ4 generated in this way are
It is indicated by a thick line with an arrow in the figure.

The stop position after driving φ1 to φ4 is point Y again.

Also, even if the motor stop position is between points X-7,
During the first drive phase φ1, if the motor starts rotating in the forward direction and is not moved to the right from point Y, the stopping position after driving will be the same as when it is stopped at point X of light. becomes point Y again.

Therefore, the ribbon feed controller 1 using the conventional drive method
In the case of rollers, due to the shift in the stopping position of the step motor caused by the deflection of trying to rotate it in the opposite direction, it is not possible to reliably generate the proper starting torque during the next drive, and rotation errors often occur. was occurring.

As described above, in the conventional drive method, if the amount of return of the motor in the opposite direction from the stop position in the stopped state is large, the starting torque during the next drive decreases, making it impossible to drive the load.

As a result, uneven density of characters, missing characters, etc. occur on the printing surface, resulting in a disadvantage that the printing quality deteriorates.

Purpose Therefore, the ribbon drive system of the printer of the present invention solves the above-mentioned problems in conventional printers, and even when the motor is rotated in the opposite direction due to the ribbon pulling force applied to the step motor in the stopped state, The purpose is to improve the reliability of the printer and obtain high-quality printing by generating a starting torque that can reliably rotate the printer in the original direction of rotation during the next drive. .

Structure For this purpose, the ribbon drive system of the printer of the present invention is equipped with a mechanism for feeding the ribbon from the ribbon supply side to the winding side, and in a printer in which the ribbon winding member is driven by intermittent driving of the step motor, the step motor is not used. When the motor is driven from a stopped state, the stopped phase, which is excited by the holding current, is switched to be excited by the drive current, and then the phase is excited with the next rotation.

In this way, before the motor rotates, by exciting the stopped phase with the drive current, the stopped position of the motor, which has been moved in the opposite direction by the load, is returned to the normal stopped position, and then the next phase is turned on with the drive current. When the motor is excited, the original starting torque required to drive the motor is generated.

In other words, the stop position is corrected by a sophisticated drive method in which the stop phase is once excited with a drive current.
Even if the motor stop position shifts in the opposite direction due to the load,
During the next drive, it becomes possible to perform the desired rotation without causing a rotation error.

Similarly to the conventional drive system, the ribbon drive system of the printer of this invention is switched so that a small holding torque is generated by φ4 HOLD in the stopped state, and the stopped position is changed by the reverse rotation torque of the ribbon, which is the driven load. Even if it is returned in the opposite direction, accurate rotational drive is always possible.

Next, regarding the ribbon drive system of the printer of this invention,
Examples thereof will be described in detail with reference to the drawings.

FIG. 4 shows a torque curve of a step motor using the ribbon drive method of the present invention.

In the ribbon drive system of the printer of this invention, when the motor is stopped in a state where it is returned from the normal stop position Y to the point X in the opposite direction due to the reverse rotation torque of the ribbon, As in, phase switching to the rotary drive phase is not performed immediately. That is, as already explained, the phase of the current stop position, that is, the phase of φ4 in the embodiments up to now, is first applied with the hold torque φ41 (CI
The drive torque is switched from LD to φ4 DRIVE, and then the phases of φ1 to φ4 are switched so that the desired rotation is performed.

Therefore, at the time of start, the torque for the stop phase is switched from hold to drive, and the motor that was stopped at point The starting torque generated by the motor enables normal rotational operation of the motor.

FIG. 5 is a block diagram showing the configuration of a conventional ribbon feed control circuit. In the drawing, 14 is a delay circuit;
5 is a mono multivibrator for hammer, 16 is a hammer driver, 17 is a set/reset flip-flop circuit, 18 is a clock generation circuit, 19 is a counter, 20
and 21 are AND gate circuits, 22 and 23 are delay flip-flop circuits, and 24 is a ribbon feed driver.

The following FIG. 6 is a time chart for explaining the operation of the circuit shown in FIG. Code A attached to each signal in the drawing
- corresponds to the same code position in the circuit of FIG.

Now, when the character selection or carriage movement operation associated with the printing operation of the printer is completed, an input pulse A is input from a control section (not shown) to the hammer and ribbon feed control circuit.

This input pulse A is applied to the delay circuit 14, and after a preset time delay B has elapsed, the hammer and ribbon feeding operations are started. The reason for providing such a time delay B is to secure the time from the end of character selection or carriage movement until the device comes to a complete mechanical standstill.

Then, at the fall of this time delay B, the hammer mono-multivibrator 15, the set-reset flip-flop circuit 17, and the clock generation circuit 18 start operating.

That is, the printing operation is performed via the hammer driver 16 in response to the hammer drive signal C generated from the mono-multivibrator 15 . Further, a drive signal for ribbon feeding is applied from the flip-flop circuit 17 to the ribbon feed driver 24, and at the same time, a ribbon feed clock E is generated from the clock generation port 1lt18.

Ribbon feed clock E rotates the motor to the next stop position with four pulses. The counter 19 is used to count these four pulses, and during that time it generates an output G and opens the gate of the AND gate circuit 21. Therefore, the output F of the gate circuit 21 is given to the delay flip-flop circuits 22 and 23, and ribbon feed phase excitation signals J and K are generated.

In the conventional control circuit shown in Fig. 5, as shown in Fig. 6, the phase switching signal J is generated at the same time as the drive signal, and when the motor starts, the next phase is immediately excited by the drive current. It is being done.

Therefore, as explained in detail in relation to Figure 3 above, if the stop position is returned to the opposite direction due to the reverse rotation torque caused by the driven load ribbon, it is ensured that the normal starting torque is applied at the time of start. cannot be caused to occur,
This causes rotation error yK'. Therefore, the ribbon feeding operation becomes inaccurate, and uneven density of characters, missing characters, etc. occur on the printed surface.

Note that four more ribbon feed clocks E are generated even after the output F of the AND gate circuit 21 is completed, but these two clocks are used to compensate for inconveniences in the ribbon feed operation.

FIG. 7 is a block diagram showing an example of a ribbon feed control circuit used to implement the ribbon drive method of the present invention. The name symbols in the drawings are the same as in Figure 5,
Further, 25 is a delay circuit, 26 is an inverter, and 27 is an AND gate circuit.

The following figure 8 is for explaining the operation of the circuit in figure 7.
Time chart I. The symbols A, L-Q, etc. attached to each signal in the drawing correspond to the same symbol position in the circuit in FIG. 7, and signals B and C, which are common to the circuit in FIG. 6, have been omitted. There is.

The drive control of the hammer is similar to the conventional circuit shown in FIG. 5.

On the other hand, in ribbon feed control, since the input pulse A is directly input to the set/reset flip-flop circuit 17, a drive signal for ribbon feed is immediately generated.

Therefore, the stop phase of the ribbon feed motor, which was previously excited by the hold current, is now excited by the drive current, and the motor moves from the stop position in the opposite direction due to the reverse rotation torque of the driven load to the normal stop position. It will be returned.

In this way, the ribbon drive method of the present invention.

Since the stop phase drive current is generated by the input pulse A, the stop position error is corrected prior to star 1~, and a normal starting torque is generated during subsequent rotational driving.

In FIG. 7, the time delay M of the delay circuit 25 is
The time is set to be the same as the time delay B of the delay circuit 14, and subsequent phase switching is performed in the same manner as in the conventional example shown in FIGS. 5 and 6.

That is, after the time delay M has elapsed, gates 1 to 1 of the AND gate circuit 27 are opened, and a signal N corresponding to the conventional drive signal is generated from the AND gate circuit 27.

This signal N causes the clock generation circuit 18 to start operating, generates the ribbon feed clock O, and counter 1
9 counts those four pulses. Then, the motor is rotated to the next stop position by the four pulses of the clock ◯.

The ribbon feed phase excitation signals J' and K' are generated at the same timing as the conventional phase excitation signal J.

In the ribbon drive system of the present invention, any inconvenience in the ribbon feeding operation can be corrected in one clock.
After the gate No. 1 is closed, the output signal N of the gate circuit 27 is set to L level at the next rising edge of the fifth clock ◯.

As described above in detail, the ribbon drive system of the printer of the present invention includes a mechanism for feeding the ribbon from the ribbon supply side to the winding side, and the ribbon winding member is driven by intermittent driving of a step motor. When the step motor is driven from a stopped state, the stopped phase, which is excited by the holding current, is switched to be excited by the drive current, and then the phase is excited with the next rotation.

Therefore, according to the ribbon drive system of the printer of the present invention, even if the stop position at rest deviates from the normal position due to the reverse rotation torque caused by the ribbon, which is the driven load, normal rotational drive is always possible. It becomes possible to do this.

As a result, the reliability of the printer is significantly improved, and uneven density of printed characters and missing characters caused by rotation errors are completely prevented, resulting in high-quality printing. can be achieved.

[Brief explanation of the drawings] Fig. 1 is a partially cutaway top view of a conventionally used film ribbon car 1-ridge, Fig. 2 is a torque curve of a step motor during normal operation, and Fig. 3 4 is a torque curve of a step motor using the ribbon drive method of the present invention, and FIG. 5 is a block diagram showing the configuration of a conventional ribbon feed control circuit. FIG. 6 is a time chart for explaining the operation of the circuit shown in FIG. 5, FIG. 7 is a block diagram showing an example of a ribbon feed control circuit used to implement the ribbon drive method of the present invention, and FIG. 7 is a time chart for explaining the operation of the circuit shown in FIG. 7. FIG. In the drawings, 1 is a cartridge body, 4 is a ribbon core, 5 is a rotating roller, 6 and 6A are film ribbons, and 7
is a feed gear, 8 is a winding shaft, 9 is a belt, 10 is a driven gear, 11 is a tension lever, 12 is a spring member, 13 is a back tension member storage part, 13A is a bank tension member, 14 is a delay circuit, 15 is a mono multivibrator for hammer, 16 is a hammer driver, 17 is a set/reset flip-flop circuit, 18
19 is a clock generation circuit, 19 is a counter, 22 and 23 are delay flip-flop circuits, 24 is a ribbon feed driver, and 25 is a delay circuit. ＼、＝、 、"、／'

Claims (1)

[Claims] In a printer that is equipped with a mechanism for feeding the ribbon from the ribbon supply side to the winding side and drives the ribbon winding member by intermittent driving of a step motor, the step motor is excited with a holding current when it is driven from a stopped state. A ribbon drive method characterized by switching the stopped phase to excite with drive current and then excitation of the phase with the next rotation.