JPS62281784A - Control unit for copying machine - Google Patents

Abstract

PURPOSE:To make the control possible which is unnecessary for adjustment according to the change of environment, by changing over the gain in PLL control according to the temperature of a DC motor. CONSTITUTION:A phase comparator 5 makes out the phase comparison signal PC from reference frequency signal FS and feedback signal FG. An addition circuit 8 adds speed control signal FV and phase comparison signal PC from the phase comparator 5. The output is supplied to a driver 10 as modulated in pulse width by a threshold level designated by an electronic volume 16 of a comparator 9. The values of electronic volumes 13-16 are set up by a microcomputer 3 to predetermined values in accordance with the output temperature signal T of a temperature sensor 22, with which are controlled the addition pay-off ratio, filter characteristic and threshold level of phase comparison signal PC and speed control signal FW.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a control device for a copying machine, and particularly to a control device for a copying machine that uses a DC motor as a drive source. .

[Conventional technology]

Conventionally, when performing constant speed control of a DC motor using phase-locked loop control (hereinafter referred to as PLL control),
Depending on the temperature characteristics of the DC motor itself, the S-
Is it the T-curve or just the amount that changes? It must be designed to cover the LiC area.

[Problem that the invention attempts to solve]

Therefore, in a conventional copying machine in which a drum or optical scanner is driven by a PLLII-controlled DC motor,
Depending on the temperature characteristics of the DC motor itself, the S-
Since the T-curve changes, there is a problem in that the gain of the PLL control must be adjusted depending on the temperature environment.

[Means for solving problems]

The present invention was made to solve these problems, and includes a means for detecting the temperature of a speed-controlled DC motor that drives a drum or an optical scanner, and a method for detecting the temperature of a speed-controlled DC motor that drives a drum or an optical scanner. It has a means for switching the gain in PLL control using a signal, and this switching means allows S to change depending on the temperature characteristics of the DC motor itself.
It is an object of the present invention to provide a control device for a copying machine that can automatically correct the -T characteristic and perform control that does not require adjustment in response to changes in the environment.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 shows a circuit diagram of an embodiment of the present invention.

In this figure, 1 is a numeric keypad that specifies the speed of the motor, 2 is an oscillator that drives a counter inside a microcomputer (hereinafter simply referred to as a microcomputer), which is a computer,
3 is a microcomputer that performs speed control, and has a first counter 3A and a second counter 3B;
A counts the clock of the oscillator 2 and generates a reference frequency signal FS for phase comparison according to the motor speed designation from the numeric keypad 1. The second counter 3B is synchronized with a feedback signal FG from an encoder, which will be described later, and generates a speed control signal FV of constant width pulses in accordance with motor speed designation. 4 is an output line, 5 is a phase comparator, and J1! is output from the output line 6 of the microcomputer 3. :Quasi Frequency Meigo FS
A phase comparison signal pc is created from the feedback signal FG and the feedback signal FG, and is output to the output line 7.

8 is an addition circuit for the phase comparison signal pc and the speed control AL143 FV, 9 is a comparator for performing pulse width variation 5q (PWM), 10 is a driver for driving the motor, 11 is a motor, and 12 is for controlling the rotation of the motor 11. The encoder for detection generates a return signal FG, which is manually input to the microcomputer 3 and phase comparator 5. 13 to 16 are electronic volumes, and 17 is a capacitor.

In addition, 18 is the FV gain control signal, and 19 is the pc gain 1t (
I 1N signal, 20 is a filter control signal, and 21 is a threshold level control signal.

Incidentally, continuous magnification change of the motor 11 can be realized by continuously changing the scanning speed of the optical system when the drum speed is constant. When the frequency of the feedback signal FG of the encoder 12 of the motor 11 for driving the optical system is set to 1 kHz during full-size copying, and the frequency is changed at a magnification of 1%ill,
The period changes every Q, Qlms. , first counter 3A
In order to invert the output port each time without repeating the count-up, the oscillator 2 is caused to oscillate at a frequency of 100kllz, and the reference frequency signal FS is generated by setting a count value corresponding to the multiplication factor in the first counter 3A.

22 is a 61 degree sensor which is a means for detecting the temperature of the motor coil. The output of this temperature sensor 22 is taken in as human power of the microcomputer 3.

Next, an outline of the operation of the embodiment shown in FIG. 1 will be explained.

The adder circuit 8 receives the speed control signal F output from the microcomputer 3.
V and the phase comparison signal PC from the phase comparator 5 are added, and the output is integrated by a filter consisting of an electronic volume 15 and a capacitor 17, and then P is determined by the threshold level determined by the electronic volume 16 of the comparator 9.
WM, the motor 11 is driven by the driver 10,
Reference circle a according to motor speed command from numeric keypad 1
The phase difference is controlled to be a constant phase difference of several degrees + FS.

In addition, the values of the electronic volumes 13 to 16 are set to predetermined values by the microcomputer 3 according to the output temperature signal ``+T'' of the 1-quality sensor 22, and the addition gain ratio of the phase comparison signal pc and the speed control signal FW and the filter characteristics are , which controls the threshold level.

Therefore, using the detection signal detected by the temperature sensor 22 to detect the temperature of the coil of the speed-controlled DC motor 11,
By means of switching the gain in control of the DC motor 11, control that does not require adjustment in response to changes in the environment is made possible.

Next, the phase comparison and speed control method will be explained with reference to FIGS. 2 to 5. In addition, in FIGS. 2 to 734, (1), (2), . . . - represent steps.

Manually set the speed (magnification) of the motor 11 using the numeric keypad 1 (1). If there is a change in the setting value (2), 'f
, 1. Set the setting value (data) to 3A. 3
), start the countdown. At this point, an interrupt progresses after the countdown of the first counter 3A ends.
Automatically resets the setting value and repeats the countdown.

The kneading generates a reference frequency signal FS. This reference frequency signal FS is then applied to the phase comparator 5. Roughly, the control temperature for setting data is set according to the temperature state of the motor coil.

Electronic volume 13 to 1 to the value corresponding to the magnification as T2
Set the value of 6 (4) to (8).

Next, let us discuss the speed control signal FV. Did you enter an FG interrupt at the fall of the feedback signal FG from the encoder 2 of the motor 11 and save the register? & (II), reset the speed control signal FV (12), set the timer value that is 1/2 FS of the reference frequency signal FS corresponding to the magnification in the second counter 3B and start it (13), and set the phase difference to 0. If ~2π (14), after register return (18),
Make it return. Also, the phase difference is not O~2π but 2
If it is equal to or higher than rt (15), the threshold level is decreased (16), otherwise the threshold level is increased (17), and after the register is restored (18), the process returns. Is the countdown of second counter 3B complete? wheat,
After an FV interrupt occurs and the register is saved (21)
, speed: By setting the FiIJO1I signal FV (22), the speed control signal FV shown in FIG. 5 is generated, and then the register is restored (23) and the process returns.

The phase comparison signal pc has a phase difference of 0 to 2 as shown in FIG.
When π, the reference frequency signal FS and the return signal FG rise F.
Repeat setting and resetting of the phase comparison signal PC,
If the phase of the feedback signal FG is delayed by 2yc or more, the phase comparison signal pc remains set and the reference frequency signal '? iF
After detecting that the feedback signal Fq has fallen twice during one cycle of S, the above-described operation with a phase difference of 0 to 2π is repeated.

Conversely, when the phase of the feedback signal FG advances, that is, when the phase difference becomes 0 or less, the phase comparison signal pc maintains the reset state, and the reference frequency signal FS increases during one cycle of the feedback signal FG. After detecting that the falling edge has occurred twice, the above-described operation with a phase difference of 0 to 2π is repeated.

When the phase difference is between 0 and 2π, the phase comparator 5 outputs "00'°," and when the feedback signal FG is delayed by a phase difference of 2π or more, it outputs "01" and the feedback signal FG outputs "01". When the phase difference is 0 or more F, a 2-bit lock signal of "10" is output, and the microcomputer 3 reads the stiffness and controls the FG interrupt routine.

According to an embodiment of the present invention, a microcomputer detects not only the specified magnification information but also the temperature of the DC motor that drives the drum or optical scanner, and calculates the change in the temperature characteristics of the DC motor that changes depending on this temperature. By automatically controlling the speed regardless of the temperature, the S-T characteristics of the DC motor that changes depending on the temperature characteristics can be automatically corrected.
There is no need to control the speed control gain according to temperature changes.Also, by using a counter inside the microcomputer and setting each adjustment part to the desired value for the specified magnification and controlling it with the microcomputer, accuracy can be achieved with a simple configuration. It provides good PLL speed control over a wide range.

In one embodiment of the present invention, the reference clock for the first counter 3A is generated by an external oscillator 2, but the microcomputer 3
It is also possible to use the internal oscillator as an internal timer reference and clock, and the motor 11 can be driven using PWM.
Alternatively, the stiffening may be performed at a DC level, and the capacitor 17 may be switched in place of the electronic volume 15 to adjust the characteristics of the filter. Furthermore, when detecting the temperature of the DC motor, similar actions and effects can be obtained even if the temperature of the coil or the temperature of the case of the DC motor is detected.

(Effects of the Invention) As described above, according to the present invention, a computer detects not only the specified magnification information but also the temperature of the DC motor itself to be controlled, and the DC motor changes depending on the temperature. The speed control is automatically applied regardless of the change in the S-T characteristic of the PLL; effective.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a flowchart explaining the operation of Fig. 1 (IN to M), Fig. 3 is a flowchart explaining the same operation (FG interrupt), Fourth
The figure is a flowchart explaining the same operation (FV interrupt), and FIG. 5 is a waveform diagram of the main part. In the figure, 1 is a numeric keypad, 2 is an oscillator, 3 is a microcomputer, 3A
is the first counter, 3B is the second counter, 5 is the phase comparator, 8 is the addition circuit, 9 is the comparator, 10 is the driver,
11 is the motor, 12 is the encoder, 13 to 16 are the electric f volume, 17 is the capacitor, 18 is the FV gain control signal, 9 is the PC gain control signal, 20 is the filter control signal, and 21 is the threshold level. Control signal 22 is a temperature sensor. Figure 2 Figure 3 1/2FS Figure 4

Claims (1)

[Claims] In a copying machine in which a drum or an optical scanner is driven by a PLL-controlled DC motor, a means for detecting the temperature of the DC motor, and a means for switching the gain in the PLL control using a detection signal detected by the detecting means. 1. A control device for a copying machine, characterized in that the switching means enables control that does not require adjustment in response to changes in the environment.