JPS6059994A - Control system for step motor - Google Patents

Abstract

PURPOSE:To reduce the noise of a step motor used for sub-scanning a facsimile by monitoring the storage capacity of n-pieces line memories, and increasing or decreasing the pulse frequency for driving a motor in response to it in a low noise range. CONSTITUTION:Compressed and fed picture information is decoded to a picture signal at every one sub scanning line by a decoder 1, a controller 4 is controlled through a memory capacity monitor 12 for monitoring the n pieces of line memory groups 11 and the storage capacity, stored in a memory 3, and the drive frequency of a step motor 7 used for feeding the sub scanning of an original of a facsimile is controlled by a speed controller 13 in response to the storage capacity. It is then continued to drive with the drive frequency of low noise range of the motor 7 during a certain time when the picture signal is stored in the memory groups 11 and the standby time is set to substantially zero. Accordingly, the noise at the time of driving the motor 7 can be effectively reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a step motor, for example, a step motor that feeds a document in a facsimile machine in the sub-scanning direction, and in particular reduces noise when the step motor is driven. (2) Prior art and problems Conventionally, sub-scanning between lines is performed in steps within the processing time of one line of a line memory that stores image signals that are compressed or decompressed during reading and recording. Facsimile machines that operate on a driving frequency every evening are widely used. In such a device, as shown in FIG. 1, the processing time for each line is Ts +
When T2 + step motor drive cycle is tl + t2, the number of drive pulses per line is TI/11.
It becomes T7□. If the number of drive pulses for each line is determined and the drive is performed evenly within the device-specific processing time (T) for one line, if the normal image information compression and decompression speed is slow, the next line will be moved. A waiting time α is generated in between.

FIG. 2 shows an example of a sub-scanning control circuit on the recording side of a conventional facsimile machine.

The compressed and sent image information is processed in sub-scanning section 1 by decompressing unit 1.
It is restored to an image signal for each line, and is sent to the recording drive unit 2 via the recording speed control unit 5 within one line processing time T by the control unit 4.
is controlled and recorded by the recording section 6. At the same time, the step motor 7 is driven at the sub-scanning frequency via the step motor drive section 6.

In this case, with respect to the 1-1-in processing time T, if the transmission speed or restoration speed is slow, a waiting time α occurs, and the sub-scanning frequency becomes intermittent in a wide range depending on the value of α, so the step The motor was making significant noise.

On the other hand, the noise generated when the step motor is continuously driven has frequency characteristics as shown in FIG.

That is, the vertical axis represents the noise level and the horizontal axis represents the driving frequency, and this characteristic is unique to Tanabata.

The peak waveform means that the step motor resonates at a certain drive frequency, and it can be seen that the noise is low at relatively high or low frequencies.

Therefore, in order to perform the low-noise drive of Step Tanabata, it is sufficient to use the low-noise area, for example, F1 to Ffi.

However, it is generally considered that the frequency characteristics of these step motors generate large noise in relation to the waiting time α.

(3) Object of the Invention An object of the present invention is to provide a control method for reducing the noise of a step motor, for example, a step motor used for sub-scanning of a facsimile machine.

(4) Structure of the Invention In order to achieve the above object, the step motor control method of the present invention uses a step motor to control the sub-scanning of the medium within the processing time of 1-)in of the line memory that stores image information. The scanning device includes a group of n line memories that store the image information, a means for monitoring the storage state of each line memory, and a drive frequency of the step motor that is controlled by the monitoring means. It is characterized in that it increases and decreases in a specific low noise region of the line memory group, and is controlled so that continuous driving can be performed between each line memory of the line memory group.

(C) Embodiments of the Invention To explain the present invention in detail, the waiting time α in FIG.
When T or α=00, the drive frequency ω of the Kti step motor is 1/#,! -No significant noise is generated.

On the other hand, in the case of 0, α, T, the driving frequency changes irregularly, which generates noise.

Therefore, it reads at high speed compared to compression and decompression speed.

When recording, α is set to 0, and sub-scanning is performed by continuous driving within the low noise range of the frequency characteristic of the step motor, for example, from Fl to -X in FIG. Then, n 2-in memories are driven for a predetermined time, and this is performed intermittently, and the waiting time during that time is set to α>T.

In this way, the low noise condition is always satisfied.

FIG. 4 is a configuration explanatory diagram of an embodiment of the present invention, in which a memory capacity monitoring unit 12 for monitoring the storage capacity of n line memories LM(1) to LM(→) is provided. Accordingly, the step motor speed control unit 1 via the control unit 4
3 is to control the driving frequency. That is,
Noise is reduced by continuously driving at the driving frequency in the low noise range (Fl to Ffm) during a certain period of time when image signals are stored in the line memory group 11. In this case, in order to prevent sub-scanning from stopping as much as possible within the limited number of line memories n, the waiting time α is variably set within the range α<2t.

FIG. 5 is a waveform diagram showing the operation of the embodiment of FIG. 4.

In the figure, Ts l T2 +...+ Tn is the processing time of each line, which is continuously driven for a certain period of time (ΣTs), and furthermore, within zTs, the number of changes due to changes in the storage capacity of the line memory group 11 The driving frequency f of the stage is F1≦f
< Fmaz and change it sequentially. However, the initial driving frequency is always p,=1/11. Subsequently, according to the storage capacity of the line memory group 11, f=
After the completion of 221%, the waiting time α is set so that α>T for T. Repeat the same procedure intermittently.

In this way, noise is reduced both during ΣTn and during the subsequent waiting time α, resulting in noiseless driving as a whole.

(G) Detailed Description of the Invention According to the present invention, the storage capacity of nine 2-inch slots is monitored, and the drive frequency of the pulse motor is increased or decreased within a low noise range according to this storage capacity. By doing so, the line memories can be driven continuously with almost no waiting time. In this way, a group of n line memories is driven intermittently, and the waiting time is set to α=0 within a group and α>T between groups, thereby reducing the noise caused by the waiting time, and By setting the motor drive frequency to a low noise range,
Overall, a step motor control system with extremely low noise is realized.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the problems of the conventional example, Fig. 2 is an explanatory diagram of the configuration of the conventional example, Fig. 3 is an explanatory diagram of other problems of the conventional example, and Fig. 4 is an explanatory diagram of the problems of the conventional example.
The figure is a configuration explanatory diagram of an embodiment of the present invention, and FIG. 5 is a waveform diagram showing the operation of the embodiment of FIG. 4 is a control section, 5 is a recording speed control section, 6 is a step motor drive section, 7 is a step motor, 11 is a line memory group, 12 is a memory capacity monitoring section, 1
3 indicates a stepsetter speed control section. Patent applicant Fujitsu Ltd. sub-agent Patent attorney 1) Yoshishige Saka

Claims (1)

[Claims] In a scanning device that uses a step motor to move the medium in the sub-scanning direction within the processing time of one line of a line memory that stores image information read on the medium or image information to be recorded on the medium, a group of line memories for storing image information, means for monitoring the storage state of each line memory, and controlling the monitoring means to increase or decrease the drive frequency of the step motor in a low noise band of the step motor; A step motor control method characterized by controlling continuous driving between each line memory of a memory group.