JPS60130966A - Sub-scanning system of facsimile device - Google Patents

Abstract

PURPOSE:To simplify the content of control by controlling the subscanning device into four operating states of stop/acceleration/constant speed movement and deceleration in response to the storage amount of a line buffer. CONSTITUTION:An output signal of a line sensor 1 is fed to a line buffer 12 as a picture signal via a video processing circuit 11. A buffer management/storage amount detecting circuit 13 detects that the storage line number of the buffer 12 exceeds the accelerating start line and deceleration start line number, and adds the detection signal to a motor control circuit 14. The circuit 14 controls a pulse motor 10 depending on four patterns comprising stop/acceleration/constant speed/ deceleration based on the detection signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a system for controlling sub-scanning means in an input/output section of a facsimile machine.

[Prior Art] In general, main scanning in the image input section and image output section of a facsimile machine is electrical, in which pulse signals are sequentially applied to elements such as a line image sensor or a multi-stylus head, but sub-scanning is A method is used in which the paper and sub-scanning means are moved intermittently by a step motor.

This is because facsimile machines are equipped with encoding/decoding means to increase transmission efficiency, and when compressing and transmitting image information, the transmission of data for one main scanning line is synchronized with the encoding/decoding means. This is because it is necessary to do so.

Incidentally, in recent years, due to the demand for higher speed facsimile machines, it has become necessary to increase the sub-scanning speed as described above.

Also, as a direction for the diversification of facsimile equipment.

For example, there have been cases where a book scanner type facsimile machine is equipped with an input unit similar to a copying machine, and the sub-scanning mechanism is not a paper feeding mechanism but a moving body with a large mass such as a mirror or a light source.

Conventionally, a so-called variable speed sub-scanning method has been proposed in order to drive such a large-mass sub-scanning mechanism at high speed.

A buffer memory is provided between the encoder and decoder means,
This is a sub-scanning method in which the sub-scanning speed is changed according to the amount of storage in the buffer memory. In this method, sub-scanning is performed continuously and the main-scanning elements are operated at timings corresponding to the sub-scanning. That is, the main scanning element is driven when the pulse motor is driven by the number of steps necessary to feed the sub-scanning object by a unit feed amount.

FIG. 1 shows a conventional facsimile transmission device using a variable speed sub-scanning method.

The figure shows a device applied to the image input section, where 1 is a line sensor that photoelectrically converts the image on the document for each main scanning line, and 2 is an image processing such as binarizing the output signal of line sensor 1. 3 is a line buffer that stores the image signal line by line, 4 is an encoding circuit that converts both signals into codes, and 5 is a line control circuit that controls the connection with the line. The circuit 6 is a modem that modulates the image signal.

Reference numeral 7 indicates a buffer management/accumulation amount detection circuit that manages the input/output of image signals of the line buffer 4 and detects the accumulation amount (number of lines), and 8 corresponds to a line number signal outputted by the buffer management/accumulation amount detection circuit 7. A motor control circuit 9 controls the speed of the pulse motor 10 constituting the sub-scanning mechanism by outputting drive pulses, and a motor control circuit 9 switches the excitation of the pulse motor every time a drive pulse is applied from the motor control circuit 8 to operate the pulse motor 10. This is a pulse motor driver.

Further, the accumulated amount (number of lines) of the line buffer 3 in the motor control circuit 8 and the speed of the pulse motor 10 (corresponding to the number of drive pulses per unit time) are set to have a relationship as shown in FIG. There is. In this case, the speed is set to change in stages according to the accumulated amount. Note that this relationship may be set to change continuously.

With the above configuration, the transmission original is converted into both signals, encoded, and transmitted to the other party's facsimile machine.(b) The amount of accumulation in the line buffer 3 and the accompanying speed change of the Norculus motor 10, that is, the change in the sub-scanning speed. An example is shown in Figure 3(a).
, shown in (b). It should be noted that the operation of each part of the apparatus shown in FIG. 1 is well known, so a description thereof will be omitted.

In this way, depending on the amount of accumulation in the line buffer 3 as shown by the solid line in FIG. 3(a), the drive pulses output by the motor control circuit 8 are changed as shown by the broken line in FIG. 3(b). The frequency changes stepwise.

Further, in a static state, the pulse motor 10 accurately rotates by a predetermined angle when a drive pulse is applied, but when the frequency of the applied drive pulse changes, it responds with a time delay corresponding to the degree of change. Therefore, the speed changes with a time delay with respect to the change in the frequency of the drive pulse, as shown by the solid line in FIG. 2(b). This effect is particularly large when the pulse motor 10 is suddenly started or stopped.

In this way, when the pulse motor 10 is accelerated or decelerated, the sub-scanning position corresponding to the number of drive pulses changes depending on the magnitude of the acceleration. As a result, it is necessary to operate the main scanning element at a timing that corresponds to this change.

On the other hand, the amount of storage in the line buffer 3 is determined by the input speed of the two signals for one line from the crawler sensor 1 and the read speed of the two signals for one line to the encoding circuit 4.

The reading speed of one line of image signals to the encoding circuit 4 is determined by the state of the image signal for each line, that is, the number and position of significant pixels in each line.

When the number of significant pixels is large, the time required for encoding is long, so the readout speed is slow; on the other hand, when the number of significant pixels is small, the time required for encoding is short, so the readout speed is fast. .

□ Therefore, the amount of storage in the buffer line 3 changes from time to time depending on the image content of the document being read, and the state of the change is not uniform and cannot be predicted.

As described above, since the amount of accumulation in the buffer line 3 cannot be predicted, the change in the speed of the pulse motor 10 described above cannot be predicted, and naturally, the change in acceleration cannot be predicted either.

Therefore, it is impossible to predict how the number of drive pulses corresponding to one sub-scanning feed amount will change, making it impossible to operate the main scanning element at an appropriate timing, and as a result, image fluctuations etc. may occur in the read image. This caused deterioration in image quality. Furthermore, in the conventional method described above, it is difficult to select the conditions for setting the relationship between the capacity of the line buffer 3 and the speed of the pulse motor 1O, and if the conditions are not appropriate, the sudden start of sub-scanning may occur. There is also the problem that stoppage and overflow or underflow of the line buffer 3 are likely to occur.

Furthermore, in the conventional method, the sub-scanning speed is controlled in multiple stages or continuously, so the control content is complicated and the cost of the apparatus is high.

Note that such inconveniences also occur when the above-described method is applied to the image output unit.

[Purpose] The present invention was made in order to eliminate the drawbacks of the prior art described above, and it is possible to achieve proper operation by simply controlling the sub-scanning mechanism in four operating states: stop, acceleration, constant speed movement, and deceleration. An object of the present invention is to provide a sub-scanning method for a facsimile machine that is capable of performing sub-scanning.

[Configuration] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 shows a facsimile transmission device according to an embodiment of the present invention.

In the figure, 11 is a video processing circuit that processes the output signal of the line sensor I and adds it to the line buffer 12 as an image signal; 13 is a video processing circuit that controls the input and output of the image signal to the line buffer 12; This buffer management/accumulation amount detection circuit detects whether the number exceeds the deceleration start line number Ld or the acceleration start line number Lu, and the detection signal DD of this buffer management/accumulation amount detection circuit 13 is a video processing circuit 11 and motor control circuit 14.

Based on the detection signal DD applied to the motor control circuit 14, a drive pulse signal corresponding to a speed control pattern as described later is applied to the pulse motor driver 9.

Furthermore, the video processing circuit 11 executes image signal transfer processing at timings described later based on the applied detection signal DD.

Note that other parts of FIG. 4 are the same as those of FIG. 1, so the same parts are given the same reference numerals and the explanation thereof will be omitted.

Now, in the present invention, the speed of the pulse motor 1° is basically controlled in a pattern as shown in FIG. 5(a). Note that this pattern is set in the motor control circuit 14.

This speed change pattern corresponds to the speed 0, that is, the stopped state S
TI, a state ST2 in which MSTI accelerates at a constant acceleration from this state MSTI to speed Va. It consists of a fixed speed state ST3 where the speed is va and a state ST4 where the speed is decelerated at a constant acceleration until it stops at the speed va.

Note that the speed va is set according to the scanning speed of the line sensor 1 and the processing speed of the video processing circuit 11.

Also, state ST2. The acceleration in ST4 is determined by the sub-scanning mechanism (
It is set based on the mass and inertia of the vehicle (not shown).

Furthermore, when the speed change pattern of the pulse motor 1o is set as described above, the position of the sub-scanning mechanism changes accordingly as shown in FIG. 3(b).

That is, the state STI in which the pulse motor 1o is stopped
In this case, the position does not change, but in state ST3 where the pulse motor 1o is moving at a speed va, the position changes at a constant speed,
State ST2. In ST4, the position changes depending on the acceleration of the pulse motor 10, respectively.

By the way, if the displacement amount for one step of sub-scanning is S as shown in the figure, then in state ST3, the sub-scanning mechanism moves by this displacement amount MS, and in synchronization with the timing, the sub-scanning mechanism moves by this displacement amount MS in the same figure (C
) A scan start pulse Ps is applied to the line sensor 1 as shown in FIG.

The line sensor 1 receives 154 pulses every time this pulse Ps is applied.
A two-minute main scan is started, and the resulting signals are sequentially output to the video processing circuit 11. Note that this pulse P
S is continuously output at the question-and-answer interval until the reading of one page of the original is completed.

The video processing circuit 11 processes the signal applied from the crawling sensor 1 as it is in state ST3, and
At I, signal input is stopped. Also, state ST2 and Sr
In 1, since the sub-scanning mechanism does not move at a constant speed, 1, for example in the same figure (
Only the output signal of the line sensor 1 when the operation starts at the timing indicated by the arrow c) is input, processed, and transferred to the line buffer 12.

FIGS. 6(a) and 6(b) show the relationship between the accumulated amount of the line buffer 12 (expressed by the number of lines) and the speed control of the pulse motor 1o. In the same figure (a), LIll represents the maximum value of the number of lines accumulated in the line buffer 12, Ld represents the number of deceleration start lines which is the number of accumulated lines for switching the pulse motor 10 from state ST3 to Sr1, and Lu represents the number of deceleration start lines for switching the pulse motor 10 from state ST3 to Sr1. It represents the number of acceleration start lines, which is the number of accumulated lines for switching from state ST1 to Sr1.

With the above configuration, the motor control circuit 14 is now controlling the pulse motor 10 to state ST3, and the line buffer 1
Suppose that the accumulated amount of 2 is increasing. At this time, the buffer management/accumulation amount detection circuit 13 detects when the accumulation amount of the line buffer 12 reaches the deceleration start line number Ld.

This is notified to the video processing circuit 11 and the motor control circuit 14 by the signal DD.

As a result, the motor control circuit 14 controls the pulse motor 10 to state ST4 to decelerate it, and the video processing circuit 11 selects the signal applied from the line sensor 1 as described above.

Thereafter, both signals accumulated in the line buffer 12 are sequentially read out by the encoding circuit 4, and when the accumulated amount decreases and reaches the acceleration start line number Lu, the buffer management/accumulated amount detection circuit 13 outputs the signal DD. This is notified to the video processing circuit 11 and the motor control circuit 14 by.

As a result, the motor control circuit 14 controls the pulse motor 10 to state ST2 and accelerates it, and the video processing circuit 11 selects the signal applied from the line sensor 1 as described above. Then, the pulse motor 10 is controlled to a state sT3 of a constant speed va.

Note that the deceleration start line number Ld is determined by the maximum value of the amount of accumulation accumulated in the line buffer 12 during state ST4, the minimum value of the amount of information transferred from the line buffer 12 during the same period, and the capacity Lm of the line buffer 12. Set based on. The number of acceleration lines Lu is set based on the maximum value of the amount of information accumulated in the line buffer 12 during the state ST2 and the minimum value of the amount of information transferred from the line buffer 12 during the same period. In addition, the capacity Lll of the line buffer 12
is mainly set based on the document size that can be transmitted by this facsimile transmitter.

In this way, the pulse motor 10 is controlled in four states: acceleration, constant speed, and deceleration, and the acceleration during acceleration and deceleration is kept constant, so the position of the sub-scanning mechanism can be reliably predicted, and as a result, image shake can be prevented. can be prevented. Furthermore, since acceleration can be performed smoothly, image quality does not deteriorate at the start of acceleration or deceleration.

Note that the timing of the pulse PS given to the line sensor l is determined when the pulse motor 10 is in the state ST2. When in the acceleration/deceleration state of ST4, the above-mentioned displacement amount MS may be changed according to the timing of movement of the sub-scanning mechanism, and is managed by the number of drive pulses. can.

By the way, although the above-mentioned embodiment is a case in which the present invention is applied to an image input section of a facsimile transmitting device, it is of course possible to apply the present invention to an image output section of a facsimile receiving device in the same way. be. In that case, the input/output relationship to the line buffer is opposite to that of the image input section, so when the amount of accumulation in the line buffer increases and exceeds a certain amount, the pulse motor is accelerated and the amount of accumulation in the line buffer decreases. The motor may be controlled so that the pulse motor is decelerated when a certain intention arises.

[Effects] As described above, according to the present invention, the sub-scanning mechanism can be moved smoothly, so high-speed sub-scanning can be realized without image deterioration. Furthermore, since the control is simple, there is an advantage that the cost can be reduced.

Furthermore, since the acceleration at the time of acceleration/deceleration is set, it is easy to determine the torque and power required for the pulse motor, and it is possible to promote cost reduction and power consumption reduction.

[Brief explanation of the drawing]

Fig. 1 is a block diagram illustrating a conventional device that implements the variable speed sub-scanning method, Fig. 2 is a graph showing the relationship between the storage amount of the line buffer and the sub-scanning speed in the variable speed sub-scanning method, and Fig. 3 (a) and (b) are graphs showing an example of changes in storage amount and changes in sub-scanning speed associated with this, and FIG. 4 shows a schematic configuration of a facsimile transmitting device according to an embodiment of the present invention. Block diagram, Figure 5 (a), (b),
, (e) is a graph illustrating the relationship between the speed change pattern of the pulse motor, the corresponding position change of the sub-scanning mechanism, and the start pulse of the line sensor, and Fig. 6 (a), (
b) is a graph diagram illustrating the relationship between changes in the storage amount and speed control of the pulse motor. DESCRIPTION OF SYMBOLS 1... Line sensor, 9... Pulse motor driver, 10... Pulse motor, 11... Video processing circuit, 12... Line buffer, 13... Buffer management/accumulation amount detection circuit, 14 ...Motor control circuit. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A line buffer of a predetermined capacity is provided between the main scanning means and the encoding/decoding means, and when the number of lines accumulated in the line buffer reaches a preset number of deceleration lines, the sub-scanning means is activated. The sub-scanning means includes a speed control means that starts deceleration to stop the sub-scanning means and also starts acceleration to bring the sub-scanning means to a predetermined speed when the number of lines accumulated in the line buffer reaches a preset number of acceleration lines. Stop means, accelerate. A sub-scanning method for a facsimile machine characterized by control to either constant speed movement or deceleration.