JPH02307394A - Method of controlling stepping motor - Google Patents

Abstract

PURPOSE:To reduce noise by driving a motor drive circuit at a pulse interval composed of three steps. CONSTITUTION:A microprocessor (MPU) 1 sets a pulse interval t1 in an interrupt generation timer circuit 7 while driving a motor drive circuit 8. When the time t1 has elapsed, said interrupt generation timer circuit 7 applies interrupt to MPU 1, which sets the next pulse interval t2 in said timer circuit 7 while driving the motor drive circuit 8 when interrupt is applied from the timer circuit 7. After that, the same operation is repeated also relative to pulse intervals t3-t5 so that the motor drive circuit 8 is repeatedly driven at said pulse intervals t1-t5 for every one line period. Thus, when the motor drive circuit 8 is driven at the pulse interval of acceleration interval as the first half and deceleration interval as the second half for every one line period, the vibration of a motor 9 becomes smaller. In this manner, it is possible to reduce noise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a stepping motor used in a thermal transfer color printer or the like.

[Conventional technology] A conventional example will be explained with reference to FIGS. 4 and 5.

Fig. 4 is a timing chart diagram showing a conventional stepping motor control method, and Fig. 5 is a characteristic diagram showing the state of vibration of the stepping motor according to the conventional control method6. In the case of paper conveyance in a printer, a stepping motor is driven at equal pulse intervals t, as shown in FIG.

That is, when printing with a color printer, a stepping motor for conveying paper was driven with 6 pulses per line, and the pulse interval t of these 6 pulses was kept constant.

Note that, as shown in FIG. 4, one line period T includes a pause time 1# (>1>).

FIG. 5 shows how the motor shaft of the stepping motor vibrates when driven by the conventional control method described above. The cause of this vibration is that because the stepping motor is driven at equal pulse intervals t with a rest time tll in between, the paper conveyance speed repeats acceleration, constant speed, deceleration, and stop, and is also due to vibrations of the paper, etc. Noise will be generated.

[Problems to be Solved by the Invention] The conventional method of controlling a stepping motor as described above has a problem in that the vibration of the stepping motor is large, resulting in large noise.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a stepping motor control method that can reduce vibration of the stepping motor and reduce noise.

[Means for Solving Problems] A method for controlling a stepping motor according to the present invention includes the steps described below.

(i) Driving the motor drive circuit at the first pulse interval at the first timing.

(ii) driving the motor drive circuit at a second pulse interval that is larger than the first pulse interval at the next timing;

(ii) At the next timing, driving the motor drive circuit at a third pulse interval smaller than the second pulse interval.

[Operation] In the present invention, in the first step, the motor drive circuit is driven at the first pulse interval.

Also, by the second step, the first pulse 1
The motor drive circuit is driven at a second pulse interval that is larger than the m interval.

Then, in a third step, the motor drive circuit is driven with a third pulse Tm ti that is smaller than the second pulse interval.

[Embodiment] The configuration of a color printer using an embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a block diagram showing a color printer using an embodiment of the invention.

In Figure 3, a color printer consists of an MPU (microprocessor) (1), an address/data bus (2) connected to this MPU (1), and a processor connected to this address/data bus (2). Durham Memory (3) and
A data memory (4) connected to the address/data bus (2), a data input circuit (5) connected to the address/data bus (2), a reference clock generation circuit (6), and this reference clock generation circuit. An interrupt generation timer circuit (7) whose input side is connected to the circuit (6) and the address/data bus (2) and whose output side is not connected to the MPU (1), and a motor connected to the address/data bus (2). Drive circuit (8
), a stepping motor (9) for paper conveyance connected to this motor drive circuit (8), and a thermal head drive circuit (10) connected to the address/data bus <2>.
and a thermal head (11) connected to this thermal head drive circuit (10).

Note that the data input circuit (5) is connected to a host computer (not shown).

Next, a method of controlling the stepping motor (9) used in the color printer mentioned above will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a timing chart showing one embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the state of vibration of a stepping motor according to one embodiment of the present invention.

In one embodiment of the present invention, for example, in the case of paper conveyance in a color printer, as shown in FIG. (9) Drive.

That is, when printing with a color printer, the stepping motor (9) is driven with 6 pulses per line,
The pulse interval of these 6 pulses is t + < t 2 < j
, > t 4 > t s.

Here, a specific method for generating pulse timing as shown in FIG. 1 will be explained.

First, the MPU (1) drives the motor drive circuit (8) and also sends the interrupt generation timer circuit (7) with a pulse interval t.
Set.

When time t1 has elapsed, the interrupt generation timer circuit (7)
Interrupts MPU (1).

When the MPU (1) receives an interrupt from the interrupt generation timer circuit (7), it drives the motor drive circuit (8) and
The next pulse interval t2 is set in the interrupt generation timer circuit (7). Thereafter, the pulse interval t.

The same operation is repeated for ~t, and the motor drive circuit (8) is repeatedly driven at pulse intervals j~t for each line period.

Note that the above-mentioned pulse intervals t1 to t may be stored in advance in the data memory (4), or may be set externally.

In this way, when the motor drive circuit (8) is driven at pulse intervals of the acceleration interval in the first half and the deceleration interval in the latter half for each line period, the vibration of the stepping motor (9) as shown by the second (2I) The vibration is smaller than in the conventional case shown in FIG.

In one embodiment of the present invention, since the stepping motor (9) is driven at the pulse interval of the acceleration/deceleration interval, the vibration of the stepping motor (9) can be reduced, and therefore the noise can be reduced. Since a damper is not required, the cost can be reduced.In the above explanation, the case where the present invention is used in a color printer has been described, but it goes without saying that it can be used in other devices as well.

[Effects of the Invention] As explained above, the present invention includes the step of driving the motor drive circuit at the first pulse interval at the first timing, and the step of driving the motor drive circuit at the first pulse interval at the next timing. The step of driving the motor drive circuit at a certain interval, and the next step of driving the motor drive circuit at a third pulse interval smaller than the second pulse interval. Vibration can be reduced Q fj
6.

[Brief explanation of drawings]

1U'A is a timing chart diagram showing one embodiment of the present invention, FIG. 2 is a characteristic diagram showing the state of vibration of a stepping motor according to one embodiment of the present invention, and FIG. 3 is a diagram showing one embodiment of the present invention. A block diagram showing the color blink used, Fig. 4 is a timing chart showing a conventional stepping motor control method, and Fig. 5 is a characteristic diagram showing the state of vibration of the stepping motor according to the conventional stepping motor control method. . In the figure, (1)...MPU, (2)...address/data bus, (3)...
Program memory, (4) ... Data memory, (5) ... Data input circuit, (6) ... Reference clock generation circuit, (7) ...
- Interrupt generation timer circuit, (8) ... Motor drive circuit, (9) ... Stepping motor, (10) -
・・ Thermal head drive circuit, (11) ・・
It is a thermal head. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] At the first timing, the step of driving the motor drive circuit at the first pulse interval, at the next timing, the step of driving the motor drive circuit at the first pulse interval.
driving the motor drive circuit at a second pulse interval that is larger than the pulse interval; and driving the motor drive circuit at a third pulse interval that is smaller than the second pulse interval at the next timing. A method for controlling a stepping motor, comprising: