JPH0340779A - Optical system controller - Google Patents

Abstract

PURPOSE:To improve stopping position accuracy of stop control by judging the state of a scanner motor by a timer interrupting, ending the interrupting when the motor is set to a driving state, and ending the stop control of the motor when the motor is set to a stopping state. CONSTITUTION:Control means 205 judges the state of a scanner motor 200 according to a detection signal from detecting means 202 by timer interrupting. When the motor 200 is set to a driving state, the interrupting is controlled to be ended. When the motor 200 is, on the contrary, set to a stopping state, stop control of the motor 200 is controlled to be ended. Thus, the stop control of the motor 200 avoids to disturb the other control, and the other control avoids to disturb the stop control of the motor 200, thereby accelerating the smooth execution of the stop control. Thus, the stopping position accuracy of the stop control is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical system control device that controls an optical system, and more specifically, the present invention relates to an optical system control device that controls an optical system, and more specifically, the present invention relates to an optical system control device that controls an optical system, and more specifically, the present invention relates to an optical system control device that controls an optical system. The present invention relates to an optical system control device that performs control and stop control.

[Conventional technology]

Generally, rotational speed control for a scanner motor for reciprocating the scanner optical system that optically scans the contents of a document is performed by controlling a control unit (e.g., a microcomputer) to control the rotational speed of a scanner motor by transmitting a pulse signal from an encoder that generates a signal synchronized with the scanner motor. In the interrupt processing in the control unit connected to the external interrupt terminal and input with the pulse signal from the encoder, the rotation speed of the scanner motor is calculated based on the period of the pulse signal, and the difference between this calculated value and the target speed is calculated. The scanner motor is controlled to rotate at the target speed by executing proportional-integral control from then on and outputting a manipulated variable according to the value of the proportional-integral control to the scanner motor.

Also, regarding stop control of the scanner motor.

The operation amount in the direction opposite to the rotational drive direction of the scanner motor is continuously output to the scanner motor, and the operation amount for the scanner motor is
It is executed by setting it to .

In particular, for exposure scanning in copying processing, which requires the scanner optical system to be driven at a constant speed, the rotational speed of the scanner motor must be stable at the starting point of the exposure scan, and a sufficient distance must be provided for this purpose. The stop position of the scanner motor must be far away. Furthermore, in order to increase the number of copies per two hours, it is better to keep the distance from the stop position of the scanner motor to the start point of exposure scanning, that is, the time it takes for the scanner motor to bring the optical system to the start position of exposure, as short as possible. To become.

In controlling the scanner optical system, a more accurate stopping position of the optical system by the scanner motor is required.

Here, the accuracy of the stop position of the scanner motor is particularly important.

However, in the stop control of the scanner motor.

Immediately before the motor stops, its rotational speed slows down and the interrupt cycle by the encoder becomes longer, making it difficult to determine whether the scanner motor has stopped within the 9th interrupt process.

Therefore, in order to solve the above problems, conventionally,
At the start of stop control for the scanner motor, subsequent encoder interrupts are prohibited.

For example, during an interrupt process that started stop control or during normal main routine processing that is not an interrupt process.

A method of waiting until the scanner motor stops under control shown in the flowchart of FIG. 10 is adopted.

That is, by starting the stop control of the scanner motor.

Outputs the amount of operation in the opposite direction to the scanner motor (
1001). Thereafter, the control unit determines whether the scanner motor has stopped (1002), and if it has determined that it has not stopped, it repeats this determination until the scanner motor has stopped. On the other hand, when it is determined that the scanner motor has stopped, the amount of operation to the scanner motor is set to 0 (1003).

In addition, as a second method, for example, as shown in FIG. 11, in a normal processing routine (main routine) that is not an interrupt process, it is determined whether the scanner motor has stopped every time the main routine completes one revolution. death.

If it is not stopped, there are other processes that continue. That is, in the main routine, the control unit determines whether or not the scanner motor has stopped (1101), and if it determines that the scanner motor has stopped, it sets the amount of operation to the scanner motor to 0 (1101). 1102), on the other hand, if the scanner motor has not stopped yet, other processing is executed, and then the determination as to whether or not the scanner motor has stopped is executed again until the scanner motor stops.

[Problem to be solved by the invention]

However, in the first method, no other processing can be performed until the scanner motor stops, which causes problems, especially when urgent processing such as abnormality processing is required.

In addition, in the second method, the time for one round of the main routine varies depending on the processing content.

The period in which the process for determining whether to stop the scanner motor is executed also varies, and the accuracy of the stop position may deteriorate. Furthermore, with this method, if the main routine takes too long per week, there is a possibility that the motor will start reversing before detecting that the scanner motor has stopped, so this method is adopted. There is a problem that you will not be able to do this.

The present invention has been made in view of the above, and it is an object of the present invention to avoid the stop control of the scanner motor from interfering with other control processes, and to prevent the stop control of the scanner motor from being interfered with by other control processes. The purpose of this invention is to promote smooth execution of stop control and improve the stop position accuracy of the stop control.

[Means to solve the problem]

In order to achieve the above object, the present invention includes an optical system for optically scanning a document, a scanner motor for transporting the optical system, and a pulse generating means for outputting a pulse signal in synchronization with the rotation of the scanner motor. , a detection means for detecting a drive state and a stop state of the scanner motor, a control means for executing drive control of the scanner motor, and an interrupt means for executing a timer interrupt process for the control means at a constant period. In the optical system control device that performs rotational speed control and stop control for the scanner motor, the control means controls the scanner motor according to a detection signal from the detection means in a timer interrupt process by the interrupt means. and when the scanner motor is in a driving state,
The present invention provides an optical system control device that terminates the timer interrupt process and terminates stop control for the scanner motor when the scanner motor is in a stopped state.

[Effect]

The optical system control device according to the present invention, in timer interrupt processing,
The state of the scanner motor is determined, and when the scanner motor is in a driving state, timer interrupt processing is ended, and when the scanner motor is in a stopped state, stop control for the scanner motor is ended.

〔Example〕

Hereinafter, nine embodiments of the present invention will be specifically described based on the drawings.

FIG. 1 shows the optical system configuration of a copying machine that employs a document table fixing method. In this method, a contact glass 101 on which a document 100 is placed.

Below the contact glass 101 is a scanner optical system 102 that optically scans the contents of the document placed on the contact glass 101. An imaging lens 103 that forms an image of information light, a mirror 104 that guides the light from the imaging lens 103 in a predetermined direction, and a dustproof glass 1
05 and.

It has a photoreceptor drum 106 that passes through the dust-proof glass 105 and undergoes exposure processing with information light according to the content of the document.

The scanner optical system 102 also includes an illumination light source 107 that irradiates light onto the original 100, a reflection Fiios that reflects the light from the illumination light source 107, and focuses the light only in the direction of the original 100; Light from an illumination light source 107 illuminates the document 100 on the contact glass 101, and a first scanner 110 includes a mirror 109 that guides the reflected light in a predetermined direction, and the reflected light from the mirror 109 is directed to the imaging lens 103. A mirror 111 that guides the direction, and a mirror 112
and a second scanner 113.

FIG. 2 shows the configuration of a drive system for driving the scanner optical system 102.

A scanner motor 200 that moves the first scanner 110 and the second scanner 113 back at a speed ratio of 2:1 so that the length of the optical path reflected from the original 100 does not change during optical scanning.
and a scanner wire 201 stretched over the scanner motor 200, and further includes a reflective type at a predetermined position of the apparatus main body for detecting the position of the scanner optical system 102 at a reference position of the scanner optical system 102. A scanner home position sensor (hereinafter referred to as HP total sensor) 202 constituted by a photo interlayer, and the first
Installed on Skyana 110.

When the first scanner 110 reaches the HP all sensor 02, the sensor 202 is turned on by blocking the light of the HP all sensor 02, and it is detected that the first scanner 110 has reached the home position. HP all sensor shielding plate 203 for.

an encoder 204 that generates a pulse signal in synchronization with the rotation of the scanner motor 200;
The pulse signal from the scanner is input as an interrupt signal, the rotational speed of the scanner motor 200 is measured from the time interval of the two interrupt signals, proportional-integral control is executed based on the difference from the target speed, and the A control unit 20 that outputs an operation amount to the scanner motor 200 and controls the rotation speed of the scanner motor 200.
5.

In the above configuration, the scanner optical system 1 is shown in FIG.
02 is indicated by a solid line, the scanner motor 200 is driven to scan the scanner optical system 102 rightward via the scanner wire 201 to expose and scan the surface of the original 100 on the contact glass 101. Furthermore, the positions of the first scanner 110 and the second scanner 113 indicated by the two-dot chain lines in FIG. Then, a backward motion will be performed.

That is, when the HP sensor shielding plate 203 installed in the first scanner 110 crosses the 1 (P sensor 202), the HP
The all-sensor shielding plate 103 blocks light from all HP sensors 02, and the control unit 205 inputs the detection signals from all HP sensors 02, processes them internally, and then outputs them to the scanner motor 20.
The scanner optical system 102 is returned from the overrun position to the home position by outputting a control signal to 0 and switching the rotational direction of the scanner motor 200 from reverse rotation (scanner forward direction) to normal rotation (scanner backward movement direction).

Further, the backward motion of the scanner optical system 102 is driven at a higher speed than the forward motion, and deceleration control is executed as the scanner approaches the home position.

Next, FIG. 3 is an explanatory diagram showing the configuration of the control circuit of the scanner optical system.

This scanner optical system control circuit serves as a control means.
J'a unit 205 (for example, μPD7811G fibrocomputer) and a programmable interval timer 301 (for example, μPD82) as a measuring means.
53C) and an oscillator 307 that outputs a clock signal to the programmable interval timer 301.
, a scanner motor 200 for transporting a scanner optical system (not shown), and a transistor 312 interposed between the control section 205 and the scanner motor 200 to control the rotation direction of the scanner motor 200. ．． Transistor 313. ) transistor 314,) transistor 3
15 and two pulse signals (A-phase encoder pulse ENCA) connected to the scanner motor 200 and having different phases depending on the amount and direction of rotation of the scanner motor 200.
and B-phase encoder pulse ENCB); and the optical system 10.
IP sensor 02 detects whether or not IP sensor 2 is at the home position and outputs the detection result to control unit 205. Also, 302 and 303 are buffers, and 30
4 is a flip-flop for determining whether or not the scanner optical system 102 has stopped; 305 is an oscillator for the control unit 205; and 308, 309 connects the output from the programmable interval timer 301 to the transistors 314, This is a gate circuit that gates 315.

In the above configuration, its operation and control method will be explained below.

Scanner motor 2 that transports the scanner optical system 102
00 is driven and controlled in its rotational direction by driving transistors 312, 313, 314° 315 connected to the control unit 205.

Specifically, when the transistors 312 and 314 are in the ON state and the transistors 313 and 315 are in the OFF state, the rotation direction is clockwise (CW) with respect to the scanner motor 200.
A current is supplied to rotate transistor 3, and conversely, transistor 3
12, 314 is in the OFF state, and the transistor 313
, 315 are in the ON state, the scanner motor 200
A current is supplied to rotate the motor in a counterclockwise direction (CCW). As described above, when the scanner motor 200 rotates clockwise (CW), the scanner optical system 102 moves forward, and conversely, when the scanner motor 200 rotates counterclockwise (CCW), the scanner optical system 102 moves forward.
), the scanner optical system 102 moves backward.

That is, the output PF6 of the control section 205 is at L level.

When PF7 is at H level, the scanner motor 200 rotates clockwise (CW) and the output PF of the control unit 300 rotates in the opposite direction.
When PF6 is at H level and PF7 is at L level, rotates counterclockwise (CCW).

On the other hand, 7' Logrammable Interval Timer 3
○UTI, which is the output of 01, is set by the gate circuit 309 to turn on the transistor 314 only while 0UTI is at the L level (to,), so a current proportional to t,11 (ON time of PWM control) flows through the scanner. motor 200
and its rotation speed is controlled.

On the other hand, when PF7 is at the L level, the transistor 313 is set to the ON state, and the transistor 315 is similarly set to the ON state via the gate circuit 308, so the scanner motor 200 rotates in the opposite direction, and its rotational speed decreases. controlled.

Further, as described above, the encoder 204 connected to the scanner motor 200 generates two pulse signals having different phases depending on the amount and direction of rotation of the scanner motor 200, namely, an A-phase encoder pulse ENCA and a B-phase encoder pulse. ENCB is generated.

The forward or reverse rotation of the scanner motor 200 is determined by the A-phase encoder pulse ENCA and the B-phase encoder pulse EN.
It is detected because the phase difference with CB is different. The principle is shown in Figure 4. Normally two-phase pulses are output at the timing shown in Figure 4, and the A-phase encoder pulse ENC
If A is used as a reference, B-phase encoder pulse E during normal rotation
The phase difference with the NCB is 90''.On the other hand, when the rotation is reversed, it is 270°, which makes it possible to distinguish between normal rotation and reverse rotation.

To explain this operation based on FIG. 3, the A-phase encoder pulse ENCA and the B-phase encoder pulse ENCB are input to the flip-flop 304 after passing through buffers 302 and 303.

Since this flip-flop 304 is a D (delay) flip-flop, if the A-phase encoder pulse ENCA and the B-phase encoder pulse ENCB have the timing shown in FIG. The Q terminal becomes H level, and in the case of reverse rotation, the Q terminal becomes L level. This is the PCT of the control unit 205
The signal is input to the terminal, and a determination is made as to whether the scanner motor 200 rotates forward or reverse. Here, buffer age) 30
2, 303 has a waveform shaping function together with the R-C circuit of each input section.

Moreover, the above A-phase encoder pulse ENCA is as follows.

The signal is input to the counter input terminal CI of the control unit 205 via the buffer 302 . Upon input of this A-phase encoder pulse ENCA, the control unit 205 measures the pulse interval of the A-phase encoder pulse ENCA using a counter (not shown) built in the control unit 205.

At the same time, the A-phase encoder pulse ENCA input to the counter input terminal CI serves as an interrupt input to the control unit 205. During interrupt program processing, which will be described later, encoder interval measurement data (ECPT) is read and this data is As a reference, the number of revolutions (scanner speed) of the scanner motor 200 is calculated, the error from the target number of revolutions (target speed) is calculated, and the motor control amount (
The pulse width variation 11 (ON time of PWM control) is calculated and the information is output to the programmable interval timer 301.

Here, the programmable interval timer 30
1 uses counter 1 and counter O of the three built-in counters, and counter O is in mode 3 (square wave rate generator, that is, generates a pulse wave with a constant ratio of H level and L level). , counter l is mode 1
(Programmable one digit, that is, a pulse wave of a constant width is generated according to the activation signal).

The tea time is set based on the information output to the programmable interval timer 301, and 0UTI
The scanner motor 200 is controlled through. Control of the scanner motor 200 is performed by pulse width modulation control as described above. That is, P W M is input to the counter O of the programmable interval timer 301.
I! The information of period J is loaded, and the output of counter O is 0UT.
A square wave with a PWM period is output from O, and this signal is input to the gate of counter 1. The ON time information of the PWM signal is loaded into this counter 1, and a one-shot output synchronized with the PWM cycle is output from 0UTI, and the transistor 314 or 315 is turned ON to 0N10FF! via the gate circuits 308 and 309. Ql.

Figure 5 shows programmable interval timer 3.
01 mode 3 (square wave rate generator) timing chart is shown.

In this case, if the set value is n, it operates as an input clock frequency division counter that outputs a pulse obtained by dividing the clock frequency by n.

In mode 3, the duty ratio when the count number is even is 1/2, and the duty ratio when the count number is odd is (n 1)/2n.

For example, if the number of counters is n-5, the duty ratio is 21
5 (active low).

As a result, when this mode 3 is selected by the control word, 0UTO=H, and the count number is loaded as GATE1-H. This starts counting.

When the count number is even, the first half of the count is 0.
UTO-H, second half becomes 0UTO-L. When the count number is odd, the first half of the count (n+1)/2
is 0UTO-H, second half (n-1) /2 is 0UTO-L
, and GATEI-L, 0UT=H in synchronization with the falling edge of GATEI-L, and the count stops. Thereafter, when GATE1-H is reached, counting is started from the initial value. If a count number is loaded during counting, a new count starts from the second cycle. If the count number is even, the counter is decremented by 2, and if it is odd, the first l is decremented when 0UTO=H.
It is decremented by 1 at the clock, and from the 2nd clock it is decremented by 2.
It will be decremented by one.

Figure 6 shows the programmable interval timer 30.
1 shows a timing chart of mode 1 (programmable one-shot).

This outputs a one-shot pulse (active low) of a specified length.

When this mode l is selected in the control word, 0
UTO=H and GATE after loading the count number
It is triggered by the rising edge of 1 and starts counting. During this counting, it becomes ○UTO-L, and when the counting ends, it becomes 0UT0-H again. In other words, the output is an active low one-shot output whose pulse width corresponds to the count number.

If a trigger is applied during counting (when GATE 1 is changed from L to H), counting starts again from the initial value. That is, 1. For example, if the set value is n, the GATE terminal changes from L to H, and the output becomes L for an interval of n clocks from the 9th order clock.

Note that even if a count number is loaded during counting, it does not affect the counting in progress, but when a trigger is applied, counting starts with a new count number.

FIG. 7 shows an example of waveforms of PWM control.

In this FIG. 7, ON time t. Even if N changes, P
This shows that the WM period (toN+torr) is constant.

Here counter 0 is set to mode 3 (square wave rate generator) and counter 1 is set to mode 1 (programmable one shot). The output 0UTO of the counter O (mode 3) repeats H2L at a constant cycle according to the set value (no). -period length t is n0
Equivalent to clock minutes. This output is the counter
(Mode I) GATE input. Therefore, the output 0UT1 is delayed by l clocks and becomes L by the set value (n,), that is, +jON from the next clock.

Since the PWM period is constant, the count number of the counter O only needs to be loaded once. Also, PWM control t
. , 4 Load the count number of counter 0 every time the time is changed.

FIG. 8 is a flowchart of the scanner motor rotation speed control and stop control processing using the C1 interrupt.

This CIIIJ processing includes the A phase encoder pulse ENC
It is executed every time A falls, and first, it is determined based on a flag (SCTST) whether the current operation control mode is rotation speed control or stop control of the scanner motor 200 (801).

If it is determined that the rotational speed control mode is selected, the control unit 205 executes a proportional integral calculation to control the movement speed of the scanner optical system 102 so that it reaches the target speed. Please calculate 802),
The pulse width modulation control is executed based on the calculation result (803). Thereafter, the 1-interrupt processing prohibition is canceled and the program returns (804). Further, if the operation mode of the scanner is stop control in 801, an appropriate amount of operation in the opposite direction to the rotation direction is applied to the scanner motor 200 (805). The application of this appropriate amount of operation to the scanner motor 200 is maintained until the control unit 205 changes the amount of operation. Next, the control unit 205 starts a timer (not shown) installed inside the control unit 205, and
Please set the timer interrupt to occur every ec806
), after masking the C1 interrupt (807), canceling the inhibition of interrupt processing (808) and returning the program.

FIG. 9 is a flowchart of stop control processing using a 500 μsec timer interrupt.

In the 500 μsec timer interrupt processing, it is determined whether or not the scanner motor has stopped (rotation or stopping of the scanner motor is determined by the flip-flop 304. In other words, the flip-flop 304 confirms that the scanner motor 200 is in reverse rotation. (considered to be stopped when
(901) If the scanner motor 200 has not stopped yet, cancel the interrupt processing prohibition (902).
), causes the program to return.

Also, if the scanner motor 200 is stopped.

The operation amount applied to the scanner motor 200 is set to 0 (903), the stop control of the scanner motor 200 is ended, the 500 usec timer interrupt is masked, and the series of processing is ended (904).

As explained above, the scanner motor stop control is executed periodically during timer interrupt processing, and when the scanner motor is not stopped, the stop control is canceled and other processing is executed. Therefore, there is little influence on other processes, and the accuracy of stop control is further improved.

〔Effect of the invention〕

As explained above, according to an optical system control device according to the present invention, there is provided an optical system control device that performs rotational speed control and stop control for a scanner motor.

The control means determines the state of the scanner motor based on the detection signal from the detection means in the timer interrupt processing by the second interrupt means, and ends the timer interrupt processing when the scanner motor is in the driving state.

On the other hand, when the scanner motor is in a stopped state, control is executed to end the stop control for this scanner motor, so that the stop control B of the scanner motor can be prevented from interfering with other control processes, and the other control processes can be stopped. Therefore, it is possible to prevent the stop control of the scanner motor from being inhibited by the stop control, promote smooth execution of the stop control, and improve the stop position accuracy of the stop control.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram showing the structure of an optical system to be controlled by the present invention, and Fig. 2 is an explanatory diagram showing the structure of an optical drive system that drives the optical system shown in Fig. 1. It is a diagram. FIG. 3 is an explanatory diagram showing the configuration of a control circuit for a scanner optical system according to the present invention, FIG. 4 is an explanatory diagram showing the principle of a method for detecting forward or reverse rotation of a servo motor, and FIG. The figure is a timing chart of mode 3 (square wave rate generator) of the programmable interval timer, and Figure 6 is the timing chart of the programmable interval timer.
This is a timing chart of timer mode 1 (programmable one shot), FIG. 7 is a timing chart showing a waveform example of PWM control, and FIG. 8 is a timing chart of C1
This is a flowchart of interrupt processing. FIG. 9 is a flowchart of 500 μsec timer interrupt processing, and FIGS. 10 and 11 are flowcharts of conventional scanner motor stop control. Explanation of symbols 100 -- Original 102 -- Scanner optical system 110 -- First scanner 113 -- Second scanner 200 -- Scanner motor 204 -- Encoder 205 -- Control unit 301
---Programmable interval timer 304
~...Flip-flop 3 12゜13゜14゜Work 5-1-Langistor Patent applicant stock Fig. 8 Fig. 9 Fig. 1O Fig. 11

Claims (1)

[Scope of Claims] An optical system for optically scanning a document, a scanner motor for transporting the optical system, a pulse generating means for outputting a pulse signal in synchronization with the rotation of the scanner motor, and a pulse generating means for outputting a pulse signal in synchronization with the rotation of the scanner motor. The scanner comprises a detection means for detecting a driving state and a stopped state, a control means for executing drive control of the scanner motor, and an interrupt means for executing a timer interrupt process at a constant period for the control means, In an optical system control device that performs rotational speed control and stop control for a scanner motor, the control means determines the state of the scanner motor based on a detection signal from the detection means in a timer interrupt process by the interrupt means, An optical system control device characterized in that when the scanner motor is in a driving state, the timer interrupt processing is ended, and when the scanner motor is in a stopped state, stop control for the scanner motor is ended.