JPS59137938A - Drive control system of scanning system driving motor of copying machine - Google Patents

Abstract

PURPOSE:To allow a scanning system to follow up accurately a main driving system by transmitting the variation in the frequency of an input power source which is caused by a synchronizing motor to the speed control circuit of a scanning system driving motor, and varying the speed of the driving motor. CONSTITUTION:An external interruption signal is supplied to the interruption terminal INT of a microcomputer 3 at an encoder pulse corresponding to the rotating speed of a scan motor M1 and the MTON scanning motor M1 is turned on for a time calculated from an expression [TON+A(FG-FG0)] according to the external interruption interval and time counted by an internal counter driven by a reference oscillation circuit 6, performing constant-speed control. In this case, TON is the reference time when the scanning motor M1 is turned on to hold a constant speed and FG is the time interval of encoder pulses; and FG0 is a set value as deviation from reference values of the rotating speed of the motor, gear ratio, copy magnification, and power source frequency, and A is a coefficient for determining the amount of correction of motor turn-on time MTON based upon the difference between the set value and a measured value. This system varies the speed of the scanning system driving motor according to the variation in power source frequency to perform stable control.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a motor drive control system, and more specifically, to a main drive system driven by a synchronous motor, and this main drive system is mechanically independent. The present invention relates to a drive control system for a scanning system drive motor in a copying machine equipped with a scanning system driven by a possible scanning system drive motor in a constant relationship with the drive speed of the main drive system.

Conventional technology In a scanning copying machine having a magnification conversion function, the relationship between the driving speed of the photoconductor and the scanning speed (v) at which the document surface is scanned is m v == V, where the copying magnification is (e). have

Conventionally, in this type of scanning copying machine, the drive system including the photoreceptor and copy paper conveyance system and the scanning system are driven by a common drive source, and when switching the copy magnification, they are driven by a drive switching mechanism such as a clutch. The speed of the scanning system was changed by changing the gear that transmits the force, etc., but such mechanical speed switching is not suitable for applications with a large number of copy magnification steps or for continuous copy magnification within a predetermined range. It is difficult to apply this to so-called continuously variable magnification.

For this reason, conventionally, the photoconductor and the scanning system are driven by separate drive motors, and the photoconductor drive motor or this motor is used to drive the photoconductor.
The rotational speed of the driven rotating shaft and the rotational speed of the scanning system drive motor are detected by a speed detection device such as an encoder, the detected values are appropriately converted and compared, and the comparison results are used as the scanning system drive motor. A system has been proposed in which a predetermined scanning speed is obtained by correlating the driving speeds of the photoreceptor and the scanning system by feeding back to a motor speed control circuit, and converting the encoder output in accordance with the copying magnification. In principle, this makes it possible to obtain any scanning speed relative to the photoreceptor drive speed, and also allows the speed of the scanning system to follow variations in the photoreceptor drive speed. be able to.

However, in this type of control mechanism, when an instantaneous load is applied to the drive motor of the drive system including the photoreceptor and its rotational speed changes, the encoder output that detects the speed changes. If this is a change that cannot be tracked by the scanning system drive motor, there is a problem in that the drive speed fluctuates and adversely affects the copied image.

In other words, even if a momentary drop in speed occurs in the motor in the photoconductor drive system, the inertia of the photoconductor etc. is large (and there is also some margin in drive transmission, so it will not affect the actual operation much). However, the output of the encoder that detects the rotational speed of the motor fluctuates, and when it is transmitted to the drive motor of the scanning system, the output of the encoder that detects the rotational speed of the motor fluctuates, and even after the rotation of the photoreceptor drive motor stabilizes when the scanning system cannot follow it. Vibration remains in the feedback control system and adversely affects the image.

On the other hand, in the method of driving the photoconductor and the scanning system separately as described above, the drive speed of the drive system including the photoconductor serves as a reference signal for controlling the speed of the scanning system, and also depends on the characteristics of the photoconductor. Since it affects the control level of charging, exposure, development, etc., it is preferable that it is not affected by slight load fluctuations or voltage fluctuations.

In this sense, a synchronous motor
If the load is within a predetermined load range that does not exceed the escape torque, the photoconductor of the copying machine will rotate accurately in accordance with the frequency of the power supply once it has been pulled into the synchronous speed, and will not slip. It can be said that it is suitable as a motor for driving a drive system including.

However, even if a synchronous motor is used to drive the drive system including the photoreceptor, the rotational speed may drop due to the instantaneous load fluctuation as described above. Therefore, if the conventional control method described above is used, the problem of speed fluctuation in the scanning system due to this drop in speed still occurs, and an expensive speed detection device is used to detect the driving speed of the synchronous motor and control the scanning system. The conventional method for controlling the drive speed of a motor vehicle cannot be said to be optimal as a follow-up control method for a drive system.

Purpose and Summary The present invention has been made in view of the above points, and focuses on the fact that a synchronous motor rotates in accordance with the frequency of the power supply. The fluctuations in the frequency of the input power source for the synchronous motor are transmitted to the control circuit of the scanning system drive motor of the copying machine, which is drive-controlled so as to have the following relationship. A drive control system for the scanning system drive motor of a copying machine that allows the scanning system to accurately follow the speed of the synchronous motor and prevents the scanning system drive motor from being affected by a momentary drop in speed of the synchronous motor. The purpose is to provide the following.

Example Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows a scanning type control system in which the control method of the present invention is applied to the main motor (B) that drives the photoreceptor drum (11) and the scanning system drive motor (M) that drives the scanning optical system (2). 1 is a cross-sectional view schematically showing the configuration of an electrophotographic copying machine (10), and first, the configuration and operation of the copying machine (10) will be briefly explained using this diagram. The main motor is a synchronous motor, and the scanning system drive motor is a DC motor whose speed is controlled by a control mechanism to be described later.

A photoreceptor drum (11) that can be rotated counterclockwise is arranged approximately in the center of the main body of the copying machine (10), and around it are a main eraser lamp (12), a sub charger (131), and a sub charger (131). An eraser lamp (lΦ), a main charger (151), a developing device (1e), a transfer charger (17), and a copy paper separation charger (formerly a blade-type cleaning device f191) are arranged in this order.

The photoreceptor drum (11) has a photoreceptor layer provided on its surface, and this photoreceptor has the eraser lamps (1B, (1)
4) and chargers (13) and (15) to be uniformly charged and subjected to image exposure from the scanning optical system (2).

Scanning optical system (■ is installed under the original glass so that the original image can be scanned, and includes a light source -, a movable mirror 021+,
t22i), a lens I24), and the interior of the mirror. The light source and the movable mirror (21)
scans to the left at a speed of (V/m) (where m: copying magnification) with respect to the circumferential speed (V) of the photosensitive drum (11) (constant regardless of whether the magnification is the same or variable magnification), Movable mirror n,
(23+ is driven by a DC motor track) to move to the left at a speed of (V/2m). In addition, when changing the copying magnification, the above-mentioned lens area) moves on the optical axis and the inside of the mirror moves and swings, but such a magnification changing device is well known, and a detailed explanation will be given here. do not.

On the other hand, there are paper feed rollers (3) on the left side of the copying machine.
1), +331, a paper feed unit (support) is installed, and the conveyance path of the copy paper is a pair of rollers (to), +351, a pair of timing rollers (to), a conveyor belt a, a fixing device (3).
8), consists of a discharge roller and a pair of rollers.

In the above configuration, the main motor (b) includes a photoreceptor drum (11), a conveyance roller (to), a shearer), a conveyor belt (
The scanning optical system (2) is configured mechanically independent of this main drive system, and is driven by the C motor (2) whose speed can be controlled. . Since the specific power transmission mechanisms of the main drive system and the scanning optical system are not directly related to the present invention, illustrations and descriptions thereof will be omitted.

In the copying operation, the main motor (c) first starts rotating in response to the input of the copying start signal, and the photoreceptor drum (11) starts rotating.
) is driven. At the same time, or with a slight time delay, the clutch of one of the paper feed rollers, I33+, is turned on, transmitting the drive of the main motor (c) to the paper feed roller, and feeding the copy paper (not shown). At the same time, the eraser lamp (12i, (1
4), charger (13), t15+, etc. are turned on.

Furthermore, after an appropriate time delay, the exposure lamp (equipment) is turned on and the DC motor (Ml) starts rotating at a predetermined speed corresponding to the copying magnification. It moves to the left and scans the original (not shown) image on the original glass, and sequentially projects the image onto the rotationally driven photoreceptor drum (11) to form an electrostatic latent image on the drum surface. Form. At this time, the copy magnification is set to the photoreceptor drum (
As mentioned above, it is determined by the rotation speed of 11) and the scanning speed of the scanning optical system (the moving speed of the movable mirror (21J)), and the lens (2) adjusts the amount of light on 1ql+ corresponding to this copying magnification. Position controlled.

The electrostatic latent image formed on the surface of the photoreceptor drum (Ql) is developed by passing through the developing device (161 section) as the drum (LD) rotates, and then moves to the transfer charger (19 section) as the drum (LD) rotates. On the other hand, the copy paper fed by the paper feed roller cill or (g) comes into contact with the timing roller (36), is temporarily stopped, and is outputted in synchronization with the image forming operation on the photosensitive drum (11). When the timing roller (to) is driven by the timing signal, it moves forward again and is sent between the photoreceptor drum (11) and the transfer charger 0, and is overlapped with the developed image on the surface of the drum (11). After being subjected to image transfer, it is separated from the surface of the drum (11J) and is discharged to the outside of the machine via a conveyance roller, a fixing device (toward), etc.

The photoreceptor drum (11) after separation is cleaned by a cleaning device (1
9) Toner and charges remaining on the surface are removed by an eraser lamp (12i, etc.) in preparation for the next copying process.

In Fig. 2, (1) is a scanning system including an illumination system, and the other side is a DC motor (scan motor).
It is possible to move forward in the direction (hereinafter referred to as scanning) and backward in the opposite direction (hereinafter referred to as return).

(2) is an encoder composed of a Hall element, which is installed on the rotating shaft of the scan motor and generates a pulse signal proportional to the number of rotations.
The moving distance of the scanning system (1) can be detected at pulse intervals and the speed of the scanning system (1) can be detected.

(5W-1 () is a home switch that detects whether the scanning system (1) is at the home position (scan start position). When it is at the home position, it emits an on signal, and otherwise it emits an off signal. emits.

(SW-B) is a brake switch that detects the reference position for the control described below for the scanning system (1), and issues an on signal when the scanning system (1) reaches a predetermined position. , otherwise it issues an off signal.

(SW-E) is an exposure switch, which is used to detect the exposure start position, etc. and perform various controls explained below.When the scanning system (1) reaches a predetermined position, it issues an on signal; emits an off signal.

FIG. 3 shows the configuration of a control device for reciprocating the scanning system (1).

(3) is a microcomputer which is the central part of control.
It consists of a readable and writable random access memory for storing data for braking, a read-only memory, an 8-bit internal counter, an input/output port, etc. (4) is a driver and protection circuit, which connects the output ports (Hg), (
Forward/reverse signal (I) from Hl), drive signal (D/S)
This controls the scan motor (Ml) and stops the motor (Ml) when a load abnormality occurs. (5) is a waveform shaping circuit which converts the pulse signal of the encoder (2) into a square wave, and the falling (or rising) signal is input to the interrupt terminal (INF) of the microcomputer (3). Reference numeral (6) denotes a reference oscillator circuit which generates a fixed frequency reference pulse for measuring the time interval (FG) of the encoder pulse signal to the external clock terminal (ECK) of the microcomputer (3).

The microcomputer (3) uses this reference oscillation circuit (6).
) is counted by an internal counter, and from the counted value, the rotational speed of the scan motor trajectory (1), that is, the speed of the scanning system (1), is calculated, and the pulse interval time is also measured.

The output signal of the power supply pulse circuit (7) is applied to the microcomputer (3) in order to measure the power supply frequency, and the speed of the scanning system (1) is corrected based on the measurement result. In this power nodeless circuit (7), the fourth
As shown in the figure, the AC power supply (
1) Connect diodes (D21) and (D2
The anodes of 2) are connected to each other, and a diode (D21)
.

The cathodes of (1) and 22) are connected to the terminal (PP) of the microcomputer (3) via a resistor (IL21). AC power supplied to the main motor via a switching element (SSR) is double-wave rectified by diodes (1) and (D22) via a transformer (IR21), current limited by a resistor 21, and then zener The signal clipped by the diode (Zl) 21) is input to the microcomputer (3) as a power pulse signal corresponding to the power frequency.

FIG. 5 shows a specific example of the driver and protection circuit (4).

In the driver circuit, the DC power supply (E) is connected to the scan motor (Ml) through bridge-connected transistors (1"rl) to (1'r4) to drive the scan motor (Ml) in both forward and reverse directions. , and the diode (Dl
) to (1)4) #(Connected in parallel with each transistor (Tri) to (Tl) to form a bypass for back electromotive voltage.

The input terminal (10a) receives the scan motor (Ml) forward rotation signal "'' and reverse rotation signal 1 from the microcomputer (3).
This is the terminal to which H" is input. It is connected to the input terminal of the AND gate (AND2), and is also connected to the base of the transistor (Tr 3 ) via the buffer (■4), and further via the inverter (11). ANDGATE (AN
DI) is connected to the input terminal of the buffer (■3
) to the base of the transistor (Tr 1 ). Another input terminal (10b) is connected to the ON signal "H" for energizing the microcomputer (3) and scan motor (Ml) and the scan motor (Ml).
This is the terminal to which the OFF signal ``L'' for not supplying current to 1) is input, and is connected to the input terminals of the AND gates (AND1) and (AND2) via the AND gate (AND3). ) (al) is connected to the base of the transistor (T'r2),
The output terminal of the AND gate (AND2) is the transistor (
1'r4).

The protection circuit is a scan motor (Ml) transistor (
The cathode of the diode (D5) is connected to the terminal to which the transistors (Tr3) and (Tr4) of the scan motor (Ml) are connected, and the cathode of the diode (D6) is connected to the terminal to which the transistors (Tr3) and (Tr4) of the scan motor (Ml) are connected. The cathodes are connected. The anodes of the diodes (D5) and (D6) are connected to the base of the transistor (Tr5) via the resistor (R6). , the + side terminal of the power supply (E) is connected through the resistors' (R5) and (Rβ), the emitter of the transistor (I'r5) is grounded, and the transistor (
The collector of Tr5) is connected to +5. ■Connected to a power source (not shown). Further, a connection point between the resistor (5) and the resistor (R8) is grounded via a constant voltage diode (ZDI).

(CO) is a counter circuit, this counter circuit 10))
The output terminal of the oscillation circuit (PG) is connected to the count input terminal (CL) of the counter circuit (CO), and the collector of the transistor (T'r5) is connected to the reset terminal (R5) of the counter circuit (CO). The count up terminal (CU) of the flip-flop (FF) is the set terminal (
S). The counter circuit (ω) outputs a pulse from the oscillation circuit (PC) when the transistor (Tr 5 ) is conductive and the terminal (R5) is 'L', and when the count value exceeds the set value, the counter circuit (ω) outputs a pulse from the oscillation circuit (PC). Tuna Flop (FF)
Set. Further, the counter circuit (CO) stops counting pulses from the oscillation circuit (PG) when the transistor (Tr5) is non-conductive and the terminal (R5) becomes H'.

In the above configuration, as will be described later, when the flip-flop (FF) is reset and the Q output is 'H', the scan motor (M
In the normal rotation mode (F (ML)) where l) rotates in the normal direction, the input terminal (
10a) turns on at 1V, the transistor (1'r3) turns on, and the AND gate (
ANDI) is *H# and Tuna transistor (Tr2)
turns on, current flows in the direction of arrow (a), and the motor (Ml
) rotates forward. Also, when in reverse mode CREV),
The input terminal 'Cl0a) switches to i Hz, the transistor ('I'rl) turns on, and the input terminal (10b) 1
At H', the AND gate CmD2) becomes 1W, the transistor ('l'r4) turns on, current flows in the direction of arrow (b), and the motor (Ml) reverses.

On the other hand, in the brake mode (FS), the input terminal (10a) is switched to "L-" and the input terminal (10b) is switched to "L-" and only the transistor (1'r3) is turned on in the reverse state.

In this case, the power to the motor (Ml) is cut off, or
Arrow (a) trying to reverse the rotation of the motor (Ml)
A back electromotive force is generated in the direction. This back electromotive force is applied to the transistor (T'r3), motor (Ml), diode (
DI), and braking against the reverse rotation of the motor (Ml), that is, regenerative braking is applied.

In addition, diodes (Di), (D2), (D3
), CD4) cuts back electromotive force during forward rotation and back electromotive force generated when switching modes, and connects the transistor (-1'
It prevents abnormal voltage from being applied to r 1 ), (Tr 2 )\ ・, ("l'r3), (1'r4).

During normal operation of the scan motor (Ml), when the input terminal (10b) is 'l-1', that is, energized, the transistor (1'r2) or transistor (Tr4) becomes conductive, and one of the terminals of the motor (Ml) becomes the collector-emitter saturation voltage of the transistor (Tr 2 ) or the transistor (T'r4). In this case, the current is the power supply (
E) through resistors (R5) and (R6) to the diode (
D5) or diode (D6), and the transistor (
The base of the transistor (Tr5) is set to a positive potential.
) becomes conductive, so the voltage across the resistor (7) decreases. This releases the reset of the counter circuit (CO), and the counter circuit (CO) starts counting pulses from the oscillation circuit (PC). Normally, the power to the scan motor (Ml) is turned off within the time determined by the set value of this counter circuit (CO), so the transistor (Tr 5 ) becomes non-conductive and the counter circuit (CO) is reset. count-up signal is not output. Furthermore, when the scanning system (1) starts returning, the scan motor (Ml) is driven at full voltage. Since the operation of turning off the energization and then turning on the energization again is repeated, the counter circuit (ω) never counts up.

However, the load on the scan monitor (Ml) is abnormally high.
or if the microcomputer (3) malfunctions, that is, in a trouble state, the scan motor (Ml) remains on, and the base of the transistor (1'r5) continues to have a positive potential. Transistor (
1'r5) continues to conduct, and a count-up signal 'l-1# is output from the counter circuit (ω), setting the flip-flop (FF) to set the Q output to 'H-' and the Q output to 1.
Make it v. This Q output signal 1 is ant game) (A
It is applied to the input terminal of the ND3) and blocks the signal from the terminal (10b), and the flip-flop (FF)
The inverter (12) is driven by the Q output signal ``H'' of
(15) The output of ' becomes IL'' and the transistor (T
r l ) and (Tr 3 ) are made conductive to stop the scan motor (Ml). In addition, the signal 'H'' of the Q output of the flip-flop (FF) is applied to the remote terminal of the power supply (E), and the power supply (E) is turned off.The trouble reset switch ( This is done by closing the switch (SW) and resetting the flip-flop (FF).

In this embodiment, the timing to apply braking to the scanning system (1) during return at full power is sequentially corrected using data measured during braking during the previous return, and braking is started at the optimum timing. Specifically, braking is started after a delay, and this count value (IM) is corrected using data measured during the previous braking.

Braking is performed in the order of regenerative braking and forward braking.
As shown in the figure, when the speed is reduced to a predetermined speed by braking,
The scanning system (1) is controlled at a constant speed and stopped when the home switch (sw-t-x) is turned on. Then, the distance traveled during constant speed control is measured and used to correct the braking delay counter (TM).

The details will be described later.

In this embodiment, the scanning system (1) first performs preliminary reciprocating motion (SC) at the start of copying in order to control the copying process.
AN: A, RETURN). The reciprocating motion (S(:AN:B, RET[JRN)) during actual copying is the optimal control corrected by the data measured in this preliminary reciprocating motion.Of course, in the second and subsequent copying reciprocating motions, The braking is corrected using the data obtained from the previous copy return.

Figures 8 to 19 show the microcomputer (3).
) is a flowchart diagram of a control program. Hereinafter, specific control will be described in detail with reference to this broached diagram.

First, the outline of the control will be explained using the main routine shown in FIG. When the power is turned on, the microcomputer (3) performs step (4) to initialize the internal parameters of the soldering iron and return the lens to its normal position.Then, in step (2), the power supply frequency is determined (details will be described later), and the step Data such as copy magnification and scan size are entered in ■.
After that, the data sword is reeled in until a scan signal is input. When the scan signal is input, "YE" is selected in step ■.
The subroutine (HOME') for returning the scanning system (1) to the home position is processed in step ■, ensuring that the scanning system (1) is located at the home position (scan start position). let

After that, the subroutine (S CAN:
A) is processed, the scanning system (1) performs a preliminary scan,
Here, data for the next actual copy scan is read. Furthermore, in step ■, the subroutine (RET
URN) is processed and the scanning system (1) is returned to the Baume position to collect data for subsequent return. Next, wait for the scan signal to be input in step ■, and if it is determined as YESJ, process the subroutine (S CAN: B) in step ■, perform the actual copy scan, and then perform the scan according to the number of copies. Step ■、■
, ■Repeat.

Here, constant speed control of the scan motor (Ml) will be explained.

For constant speed control, an external interrupt is applied to the interrupt terminal (lNT) of the microcomputer (3) at the fall (or rise) of the encoder pulse corresponding to the rotation speed of the scan motor (Ml), and this external interrupt interval and reference oscillation are According to the time counted by the internal counter driven by the circuit (6)
'rON + A (FC-FGo)] The time (MrON) scan motor (M□
) (see Figure 7). Note that ('rON) is the reference time for turning on the scan motor (Ml) to keep it at a constant speed, (FC,) is the time interval of the encoder pulses measured by the above internal counter,
(FGo) is a setting value set based on the amount of deviation from the reference value of the motor rotation speed, gear ratio, copy magnification, and power supply frequency. Therefore, (A) is a coefficient that determines the amount of correction of the motor on time (MTON) due to the error between the set value and the actual measurement value. Here 1. Cr0N) is corrected by the value of (FC) in scan time constant speed control, and the value obtained by further correcting that correction value by A (FC-FGo) is used as the motor on time (MTON), so the motor on time (MTON) is
MTON ) is doubly corrected to a more appropriate value τ.

In this embodiment, there are two types of constant speed control: during scanning and near the end of return. Also, when scanning, the scanning speed differs depending on the copy magnification, so the above (FGo), (
A), ('rON) has multiple values.

The timer interrupt and FC interrupt in the constant speed control are scan and return subroutines (1; GWAI'r
), (MCOFF). Nao, timer interrupts are also allowed at the start of return.

A timer interrupt is generated every time the internal counter overflows due to a pulse input from the reference oscillation circuit (6) to the external clock terminal (ECK) of the microcomputer (3). The internal counter continues counting from zero again even after overflow. In this embodiment, the internal counter is 8 bits, and the frequency of the reference oscillation circuit (6) is set to 200 KHz.
Therefore, 28 = 256 clocks (1,28 mg
), a timer interrupt is generated.

This timer interrupt is received after the FC interrupt processing described later, and as shown in the processing routine (IN'r・'r) in FIG. 9, the motor on time (M'rON
) has elapsed, and if it is determined as 1'-YESJ, the drive OFF data is output in step 〇3■ and the process returns to the main routine.
If MTON) has not passed, step 〇3 is 1N.
o" and immediately returns to the main routine. The above drive OFF data is stored in the FC interrupt processing routine (INT).
RA of the microcomputer (3) before the drive ON data executed in -F) and the Tomoni interrupt are enabled.
Set within the M area. The ON-OF data is a combination of a forward/reverse signal (F/R) and a drive signal (D/S). (F) is forward rotation, (R) is reverse rotation, (D) is drive, (S
) means stop.

Immediately, soon
), OFF data is (FS), ON data (RD) during constant speed control during U-turn, and O'F7'-Y (R5). On the other hand, the control data for the motor (M□-) when constant speed control is not performed is the forward/reverse signal (F/
R) and the drive signal (D/S'), for example, the control data during forward braking during return is (F D ), and the control data during regenerative braking during return is (FS) It is.

When the timer mode is "1", that is, from the start of return to the start of regenerative braking, the interrupt routine (IN"r
OFF data (R
5) to ON data (RD) and set the scan motor (
Ml) is temporarily de-energized and the protection circuit counter circuit (
CO) to prevent count-up. Since this energization stop time is about several microseconds compared to the energization time (maximum protection circuit detection time) at return, it has little effect on the return speed.

FC interrupt processing is generated by the fall (or rise) of the encoder pulse corresponding to the rotation speed of the scan motor (M□), and is mainly used to calculate the time (M'rON) for turning on the scan motor (M). conduct. That is, as shown in FIG. 10, in step C) the time since the previous FC interrupt (
FG) is calculated, and the set value (FGo
) and calculate the difference (ΔFG) from ゛rON at step [Φ
Determine whether there is a correction request. The ``rON correction request'' is set to 1'' from the time when the exposure switch (SW-E) is turned on until the end of scanning, and returns ``NO''. "
YES If J, the pulse interval (FG) is equal to the set value (F
C) and the scanning speed of the scanning system (1) is slow, so in step &, a predetermined value (1 in this example) is added to the reference time ('rON), and the predetermined value is set to the reference time ('rON).
).

Next, in step (W), it is determined whether (1ΔFCI≦K). (K) is the measured value of the encoder pulse interval (
It is a constant that determines the allowable range of the difference (ΔFG) between It makes a decision, outputs the data with l'-YES J, and returns to the main routine. Output step OFF data and return to the main routine.

On the other hand, if (1ΔFGI) is within the allowable range), the motor on time (MTON) is calculated, drive ON data is output in step QN, and the process returns to the main routine.

FIG. 11 shows the subroutine (HOME). If the scanning system (1) is not at the home position at the start of scanning, the main motor (Ml) is reversed and the scanning system (1)
This is a subroutine that returns the home position.

That is, in step [phase] the home switch (SW-14
) is off, and if "NO", the scanning system (1
) has returned to its home position, so it immediately returns to the main routine. ``If YES J, the scanning system (1) is far from the home position, so first, in step ■, the control data is set to (RD) to drive the motor (M□) in reverse, and in step @, the motor (M□) is driven in the reverse direction. Set data (FC6), ('rON), (A),
After setting (RD) and (R5) in the V5 Eve 0N-OFF data, the subroutine (FGW
AVr) is executed, and constant speed control is performed.

Here, after confirming that the scanning system (1) has turned on the home switch (SW-1 () in step 0, that is, the scanning system (1) has returned to the home position, interrupts are disabled in step [phase]). Execute the routine (MCOFF), turn off the constant speed control, set the stop timer at step (φ), and move on to the stop operation (fixed position control). That is, at step 0, the control data is set as (ILD) and the motor is The motor (Mo) is driven to rotate in the normal direction and waits for the termination of the stop timer in step [phase].The reason why the motor (Mo) is rotated in the normal direction here is to cancel the reverse speed at the time of return. After the stop timer expires, the control data is set to (p, s) in step [phase] to stop the scan motor (Mi), and the process returns to the main routine.

As shown in Fig. 12, the subroutine (FGWAI) allows interrupts for constant speed control.
Wait for the falling input of the encoder pulse at step [Phase], set the °rON correction length to 0'' at step ■, enable interrupts at step [phase], and return to the main routine.

The subroutine (MCOFF) is for terminating the constant speed control as shown in Fig. 13. After inhibiting interrupts in step [phase], the control data is transferred to (R) in step (phase).
5) Stop the motor (M□) and return to the main routine.

FIG. 14 shows the subroutine (SCAN:A).

(SCAN:A) is the actual copy scan (SCAN:B)
) is a pre-scan execution routine performed prior to the copy scan (SCAN:B), in which the data of the motor-on time (M'rON) used in the subsequent copy scan (SCAN:B) is set.

First, in step [phase], (FD) is set in the control data to drive the motor (Ml) in normal rotation. This full-power normal rotation drive continues until the first encoder pulse input is received and helps the scanning system (1) to start up. Then, turn on the drive to the RAM area of the microcomputer (3).
As data (RD), as drive OFF data (
FS) settings are performed. Next, in step [Yes], initial data is set in the braking delay counter ('rM) at the time of return. Next, in step [phase], constant speed control data (FGo), ('l0N) is generated based on the copying magnification.

Set (A). At the same time, the correction value of the counter calculated from the scan size in the copy scan (5CAN, 13) in step (2) is set as (CT).

This is because the preliminary scan (SCA'N:A) is set to the minimum scan size and is usually shorter than the actual copy scan (5CAN:B), and the braking start timing changes depending on the scan size. (SCAN:A) This is to correct the counter measurement value in the subsequent turn.

Next, in step [Yes], the subroutine (FGWA I
T), waits for the first encoder pulse input, and starts constant speed control. Then, in step [phase], wait for the exposure switch (SW-E) to be turned on in the scanning system (1), and when it is confirmed that the exposure switch (SW-E) is turned on, step [phase]
Set the counter to the pre-scan size in step (3), set the rON correction request to @1", and wait for the reference time (rON) to converge.
Step [phase] The counter that started when E) is turned on counts the number of pulses set for the preliminary scan size.
Wait at , and when it is finished, the subroutine (
MCOFF) is processed, interrupts are disabled, and constant speed control ends. The reference time ('rON) corrected in this preliminary scan (5CAN:A) is saved in the register ('rONR) in step ■, and thereafter this data is used in the exposure switch (5W) in the copy scan (SCAN:B). -E
) is used for constant speed control until it turns on.

FIG. 15 shows the subroutine (SCAN: B).

(5CAN: B) is the preliminary scan (SCAN:
This is a copy scan execution routine performed after A).

First, in step @, the motor (Ml) is driven in the normal rotation like the step [phase] of the preliminary scan (SCAN:A),
The drive ON-OF data is set, and the braking delay counter ('rM
) is corrected. That is, find the difference between the constant speed control distance (Cr) measured during return and the constant set value (CK), which will be explained below, and add that difference to the data ('rM) set last time (preliminary scan). do. Next, in step @, the counter is cleared in order to measure the braking timing of the next turn. At the same time, in step [phase], the constant speed control data (F
GQ) and (A), and in step [phase], the reference time (5CAN:A) obtained in the preliminary scan (5CAN:A) is restored.
'rON) is restored.

Next, in step [phase], the subroutine (FC, WA I
T) is processed and constant speed control is started. Then, in step [phase], the exposure switch (SW-E) is switched to the scanning system (1
), and when it is confirmed that it is turned on, the counter is set to the actual copy scan size in step O, and the 'rON correction request is set to "1" in step [phase].
, and start correcting the reference time ('rON).

Waits in step [phase] for the counter started when the exposure switch (SW-E) is turned on to count the number of pulses set for the copy scan size, and when finished, processes the subroutine (MC0FF) in step [phase], Interrupts are disabled and constant speed control ends.

FIG. 16 shows the subroutine (RE'rURN).

First, in step [phase], (RD) is set in the control data to drive the motor (Ml) in reverse at full power, and in step 0, the constant speed control data during scanning is stored in the microcomputer (3). Save to register. at the same time,
By processing the power supply frequency check routine (CHECK) described later in step [phase], setting the timer mode to "1" in step [phase], and allowing only timer interrupts in step @, the return is executed at regular intervals. Full voltage drive is turned off instantly. Then, in step @, it waits for the brake switch (SW-B) to be turned on in the scanning system (1). When this brake switch (SW-Is) is turned on, the braking delay counter (
TM) and wait for its completion at Stella O. The set value of this counter ('rM) is the value of the initial data set in step ■ if it is a return after a preliminary scan, and the value corrected in step ■ if it is a return after a subsequent copy scan. . Counter ('r
When M) is completed, the timer mode “
1", set (FS) to the control data in step [phase], apply regenerative brake to the scan motor (Ml), and set the predetermined value (
'r c ) and waits for the count to end at step O. At the end of the count, (FL) is set in the control data at step 0, and the forward rotation brake is applied to the motor (Ml). In this way, when the rotation speed of the motor (Ml), that is, the return speed of the scanning system (1) is decelerated to a predetermined speed or less, this is detected in step @, and the reverse constant speed control data is transmitted in step setting, and constant speed control of reverse rotation is performed. That is, the control data (RD
) and reverse the motor (Ml),
Drive ON data (R1)) and drive OFF data (R5) are set, and in step [phase] a subroutine (FGWAI) is processed to perform constant speed control.

Next, set the counter at step @, and step 0
The number of encoder pulses until the home switch (SW-14) is turned on in the scanning system (1) is counted, and the counted number (Cr) is saved in steps [phases]. The count number (c) accurately corresponds to the distance traveled by the scanning system (1) during constant speed control, and the number of counts (c) accurately corresponds to the distance traveled by the scanning system (1) during constant speed control. Used for calculations. Then, in step [phase], a subroutine (MCOFF) is processed, interrupts are prohibited, and constant speed control ends.

After that, the fixed position control, that is, the subroutine (HOME
) The same control as in steps [phase] to [phase] is performed, and the scanning system (1) stops at the home position.

That is, in the present invention, a braking delay counter (
'rM) set value ('IMn+1, n number of scans) was measured during constant speed control of the previous return (steps [Yes] to [Phase]). The moving distance during constant speed control of scanning system (1) The optimum braking timing is obtained by successively correcting the data (Crn) shown in FIG.

Expressed as a control equation, rM n+1-'rM n + C
'l-n-CKCK: Constant set value This correction acts so that (CTn=CK). In other words, when (Crn goes to C), the braking timing is earlier, but the next count setting value ('rM
, +□) is the previous count setting value (Mn). rMn+□) from the previous count setting value (
'rMn).

That is, in either case, the next count setting value ('rM
n+l) to a constant value ('r
M).

FIG. 17 shows a routine for checking the power frequency of the main generator (M).

In step φ boil, according to the power supply frequency 59Hz or 5QHz determined when the power is turned on, step φ → or (set the number of boil measurement pulses to 6 or 5 and make the measurement time the same and make corrections. As a result,
The value obtained by subtracting the standard time 50 + ns is the current amount of frequency fluctuation, and in order to convert this amount of fluctuation into a magnification, it is divided by the change step and used as the frequency fluctuation evaluation constant PSFT.For example, if the magnification data is 1/1000
If it is pitch, the change step is 1/1 of standard time 5Qms.
The result is division by 50 μs, which is 1000. This power supply frequency check is performed every time the scanning system (1) returns, and PSF'F is added to m (magnification + shift amount) calculated by the step (boiled shift person calculation) to calculate the speed in the next scan. In order to do this, FGO is recalculated in step U.

FIG. 18 shows a routine for determining the power frequency of the main motor (M).

In this routine, the current power frequency at power up is 5.
A determination is made as to whether the frequency is QIlz or 5QHz.

is measured, and the time measured in step ψ) is 55H
The power supply frequency is 60 depending on whether it is shorter than the period of z.
) 1F, or 50 [■l] is determined.

The power supply pulse has a cycle of 6 pulses during double-wave rectification, which is 5Q'
59m5 at Hz, 54.5ms at 55Hz.

5QI-1z is 50m5, so the measurement result is 54
．． If it is shorter than 5mM, it is determined to be 5QI-1z.

FIG. 19 shows a lens movement routine for changing the copying magnification.

If the magnification data differs from the previous magnification during data input, it is assumed that the magnification has changed and the lens is moved. In step (2), a predetermined lens position is determined from the magnification before and after the change using a table or calculation, and the difference between the determined lens position and the previous lens position is taken as the amount of lens movement. When the step is determined, the moving steps are made into a pair by step Φ→. Step■, ■Excitation of the stepping motor for moving the boiled lens. By shifting the
The lens is moved to complete the movement of the predetermined number of steps.

Effects As explained above, in the present invention, fluctuations in the frequency of the input power supply of the synchronous motor that drives the main drive system are transmitted to the speed control circuit of the scanning system drive motor that drives the scanning system, and the fluctuations in the power supply frequency are Since the speed of the scanning system drive motor is changed accordingly, the scanning system can accurately follow the main drive system with a simple configuration, and even if there is a momentary drop in the speed of the synchronous motor, the scanning system can be maintained. Stable control can be performed in which the system drive motor is not affected by this.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of the copying machine, Fig. 2 is a perspective view of the scanning system, Fig. 3 is a block diagram of the control device, Fig. 4 is a circuit diagram of the power supply pulse circuit, and Fig. 5 is a driver and Circuit diagram of the protection circuit, Figure 6 is a graph showing the speed change during scan and return of the scanning system, Figure 7 is a pulse waveform diagram to explain constant speed control, and Figures 8 to 19 are the control device. This is a flowchart. (1)...Scanning system, (3)...Microcomputer, (4)...Driver and protection circuit, (5)...
Waveform shaping circuit, (6)...Reference oscillation circuit, (7)...
・Power pulse circuit, (1G+...copy machine, (11)・
・・Photoconductor drum, (→・・・Main motor, [1)・
...Scan motor patent applicant Minolta Camera Co., Ltd. Representative Patent attorney Aoyama Aoyama and two others Figure 2 Figure 3 Figure 4 Figure 8 Figure 9 Figure 14 Figure 15 Figure 17 Figure 18

Claims (1)

[Claims] (1) In a copying machine equipped with a main drive system driven by a synchronous motor and a scanning system driven by a scanning system drive motor that is mechanically independent from the main drive system and whose speed can be controlled, A motor drive control system, characterized in that fluctuations in the frequency of an input power source to the synchronous motor are transmitted to a speed control circuit of the scanning system drive motor, thereby changing the speed of the scanning system drive motor.