JPS60100132A - Deceleration controlling system of scanning system - Google Patents

Abstract

PURPOSE:To reduce a vibration of a scanning system, and to stop it exactly at a fixed position by moving the scanning system by inertia when shifting it to a constant speed control state from a damping state, at the time of a returning motion of the scanning system. CONSTITUTION:A preliminary reciprocating motion SCAN-A, RETURN going ahead of copying and a reciprocating motion SCAN-B in case of copying are used as a control data. At the time of a returning motion, when on of a brake switch SW-B is detected in the course of reset by a full power, a damping means operates after a prescribed delay time. When it is decelerated to the first prescribed speed which has been set as a control data, the damping is released, and when it becomes the second prescribed speed which is lower than the former, it is brought to a constant speed control to the home position, and stopped by detecting on of a home switch SW-H. Each step is shifted smoothly by executing an inertia movement between a damping period and a constant speed period.

Description

Detailed Description of the Invention Technical Field The present invention relates to a deceleration control method for a scanning system driven reciprocally by a DC motor, such as a scanning system for exposing an original image onto a photoreceptor through a slit in an electrophotographic copying machine. It is.

2. Description of the Related Art Image scanning systems in electronic copying machines generally have various scanning modes, ie, various scanning speeds and scanning distances, depending on the size of the original or copy paper or the copying magnification. Therefore,
As a scanning device, it is necessary to control the backward movement so that the scanning system always stops at a fixed position (home position) in various scanning modes. If the stop position of the scanning system varies, it is necessary to provide a sufficient preparatory movement distance for the vertical movement at the start of scanning, which can lead to problems such as an increase in the size of the scanning device and an increase in the reciprocating time. be.

Therefore, the present applicant has already proposed in Japanese Patent Application No. 57-122365 that when the speed of the scanning system reaches a predetermined speed due to braking during the backward movement of the scanning system, constant speed control is performed at that speed to reach the home position. We proposed a deceleration control method to restore the In this method, no matter how the return start position changes, the speed just before the home position of the scanning system remains constant, so the return position of the scanning system to the home position can be accurately controlled. It is possible to control the rise of the forward motion over a short distance.

However, even if the braking state changes to the constant speed control state at the same speed, it does not necessarily mean that the transition is smooth, and if the scanning system load fluctuates for some reason, vibrations will occur in the scanning system. Measures against vibrations are necessary.

Purpose The present invention has been made as an improvement to the deceleration control method described above.The purpose of the present invention is to provide a deceleration method for the scanning system that allows the transition from the braking state to the constant speed control state to be extremely smooth and to minimize vibrations in the scanning system. The objective is to provide a control method.

In order to achieve the purpose of [Summary], the scanning system deceleration control method according to the present invention is such that the scanning system is driven from the forward movement end position in the return direction during the backward movement of the scanning system that is driven reciprocally. Post-braking is applied to decelerate the scanning system, and when the speed of the scanning system reaches a first predetermined speed, the braking force is released and the scanning system is inertially moved, and the speed of the scanning system is lower than the first speed. 2
When the speed reaches a predetermined speed, constant speed control is performed at this second speed to return to the home position.

That is, during the backward movement of the scanning system, the scanning system is inertially moved when transitioning from the braking state to the constant speed control state, thereby making this transition smooth.

Embodiment Hereinafter, one embodiment of a scanning system deceleration control method according to the present invention will be described with reference to the accompanying drawings.

This embodiment is applied to an electrophotographic copying machine. In Fig. 1, (1) is a scanning system including an illumination system, (Mo) is a DC motor (scan motor), and the scanning system (1) is a scanning system including an illumination system. The scan motor (M
(hereinafter referred to as return) is possible.

(2) is an encoder composed of a Hall element, which is installed on the rotating shaft of the scan motor (M□) and generates a pulse signal proportional to its rotation speed. It is possible to detect the distance traveled and the speed of the scanning system (1) in pulse intervals.

(SW-H) 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. emanate. (SW-B) is a brake switch that detects the reference position for the control described below for the scanning system (1).
When it reaches a certain position, it emits an on signal, and otherwise it emits 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. 2 shows a control block diagram for reciprocating the scanning system (1).

(3) is a microcomputer which is the central part of control.
Reading 1'1- for storing data for braking control
It consists of writable random access memory, read-only memory, 8-bit internal counter, input/output ports, etc. (4) With the ζ driver circuit, the 7Jl port (1-1o) of the microcomputer (3),
Forward/reverse signal (■ゝ/R) from (n, ), drive signal (
D/S) controls the scan motor (Ml). (5) is a waveform shaping circuit TE, and 7 of the encoder (2).
The f7less signal is converted into a Jb wave, and its falling (or rising) signal power is input to the interrupt terminal (INT) of the microcomputer (3). (6) is a reference oscillation circuit, and the encoder - A fixed frequency reference pulse for measuring the time interval (T'G) of the pulse signal is issued to the external clock terminal (Ii, CK) of the microcomputer (3). The pulses from the semi-oscillation circuit (6) are counted by an internal counter, and the rotational speed of the scan motor (Ml), that is, the speed of the scanning system (1), is calculated from the counted value.

On the other hand, (M2) is the main DC current source for driving the photoreceptor drum, etc., and is rotated by an encoder (2') similar to the scan motor (Ml) for constant speed control. A pulse signal proportional to the number is issued to the control circuit (9) and the microcomputer (3). (7) is a DA converter which converts the signal emitted from the output capo (Po) into an analog signal based on the pulse from the encoder (2'). (8) is an adder circuit which adds the output from the DA converter (7) and a reference voltage corresponding to the minimum allowable speed to obtain a drive voltage, sends this to the control circuit (9), and uses this to control the main motor. (M2) is controlled at a constant speed.

FIG. 3 shows a specific example of the driver circuit (4).

The DC power supply (E) is a bridge-connected transistor C1.
Scan motor (M□) via “rl) ~ (Tr4)
The diodes D1) to (D4) are connected to each transistor (Trl) to form a bypass for the back electromotive voltage.
(Tr4) is connected in parallel.

Input terminal (10a) has forward rotation signal “H” and reverse rotation signal “L”
It is connected to the input side of the AND gate (AND□) and the base of the transistor (Trl), and is connected to the AND gate (AND
It is connected to the input side of the transistor (ND2) and the base of the transistor (T,3).

The other input terminal (10b) is an on signal "■-B,"
The off signal “L” is turned off, and the AND gate (A
Connected to the input side of ND, ), (AND2).

In addition, how the AND gate (AND) is formed (III is the base of the transistor (Tr2)),
The output side of 2) is connected to the base of the transistor (Tr4).

In the above configuration, in the forward rotation mode (FD), the transistor (Tr3) is turned on when the input terminal (10a) is 1 bit, and the AND gate (A
NDl) becomes “TI” and the transistor (T r
2 ) turns on, current flows in the direction of the arrow ( ), and the motor (
Ml) rotates normally. In addition, in the reverse mode (RD), the input terminal (102) is switched to @L'', the transistor (T r 1) is turned on, and the input terminal (lob) is @H.
"And gate (ANI) 2) is turned on" and the transistor (Tr, i) turns on, and the current flows as shown by the arrow (
It flows in the direction b) and the motor (M□) reverses.

On the other hand, in the brake mode (FS), the input terminal (10a) is connected to "I-1" and (10b) in the reverse rotation state.
is switched to @I-" to turn on only the transistor (T r 3). In this case, the current to the motor (M□) is cut off, but the arrow (a) that attempts to reverse the rotation of the motor (Ml) ) direction is generated.This back electromotive voltage is generated by the transistor (Tr3) and the motor (Ml).

It flows through the diode (DI), and brakes against the reverse rotation of the motor (Ml), that is, regenerative braking is applied.

Note that diodes (DI), (D2), (D3), (D
4) is a transistor (Trl) that cuts the back electromotive force during forward rotation and the back electromotive force generated when switching modes.

This prevents abnormal voltage from being applied to (Tr2), (Tra), and (Tr, i).

Here, the feature of the present invention is that the scanning system (1) is braked during return to decelerate it, and when it has decelerated to a certain speed, the braking force is released and the system is moved by inertia. The point is that when the vehicle is decelerated to this speed, constant speed control is performed at this speed.

Furthermore, 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, after the scanning system (1) turns on the brake switch (SW-B), the braking is started after a delay of (TM) using the braking delay counter ('1''M), and this count value is (TM) is corrected using data measured during braking of i7I.

Braking is performed by regenerative braking and forward braking, and as shown in Figure 4, when the speed is reduced to a predetermined speed by braking, constant speed control is performed at that speed and the scanning system (1) returns to home. Stop when the switch (SW-IJ) is turned on.

In this embodiment, in order to control the copying process, the scanning system (1) first performs a preliminary reciprocating motion (SCA) at the start of copying.
N: Execute A, RETURN). The reciprocating motion (SCAN:B, RETURN) during actual copying is optimally controlled by correcting data measured in this preliminary reciprocating motion. Of course, the braking during the second and subsequent copying movements is corrected using the data obtained from the previous copying return.

Figures 6 to 14 show the microcomputer (3).
) is a flowchart diagram of a control program. Hereinafter, specific control will be described in detail with reference to this flowchart.

First, the outline of the control will be explained using the main routine shown in FIG. When the power is turned on in the microcomputer (3), initial settings of internal parameters are performed in step ■, data such as copy magnification and scan size are input in step ■, and the process continues until a scan signal is input. Repeat data entry. When the scan signal is input, ``YES J'' is determined in step ■, and the subroutine (HOME) for returning the scanning system (1) to the home position is processed in step ■, and the scanning system (1) is confirmed. Position it at the actual home position (scan start position).

Thereafter, the subroutine (SCAN:A) is processed in step (2), and the scanning system (1) performs a preliminary scan to read data for the actual copy scan to be performed next. Furthermore, in step ■, the subroutine (RETURN
) is processed and the scanning system (1) is returned to its home position to collect data for subsequent return. Next, wait for the scan signal to be input in step ■,
[If YES J is determined, the subroutine (SCAM, B) is processed in step 2, actual copy scanning is performed, and thereafter step 2 is executed depending on the number of copies.

Repeat ■ and ■.

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 (INT) 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 Depending on the time counted by the internal counter driven by the circuit (6) (
The time (MTON) calculated using the formula TON + A (1iG - I'C, o) ) is performed by turning on the scan sensor (Ml) (see Figure 5).
. Note that (TON) 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 internal counter, (
1'GO) is a setting value set based on the motor rotation speed, gear ratio, and copy magnification. 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, (TON) is corrected by the value of (FG) in scan time constant speed control, and the value obtained by further correcting that correction value by A (1'G-FG□) is the motor on time (MTON). Therefore, the motor on time (M-rON) is doubly corrected to a more appropriate value.

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 (FGo), (
A), (TON) has multiple values.

The timer interrupt and FC interrupt in the constant speed control are scan, return subroutine (FGWAIT), (
MCOFF).

A timer interrupt occurs 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 200KIIZ.
Therefore, 2" = 256 ri o7ri (1,28 m
5), a timer interrupt occurs every time.

This timer interrupt is accepted after FC interrupt processing, which will be described later, and the motor on time (MT
ON) has elapsed, and if it is determined as YES J, drive OFF data is output in step C[]D, and the process returns to the main routine. Note that if the motor on time (MTON) has not elapsed, step CEE)
The determination is "NO" and the process immediately returns to the main routine.

The drive OF data is sent to the microcomputer (3) together with the drive ON data executed by the PC interrupt handling routine (INT-F) before the interrupt is enabled.
is set within the RAM area of 0N-OFF data is a combination of forward/reverse signal (1”/R) and drive signal (D/S). (F) is forward rotation, (R) is reverse rotation, (D) is drive, (S) is means stop.

That is, the ON data during scanning is (FD), the OFF data is (FS), the ON data during constant speed control during return is (RD), and the OFF data is (R5). On the other hand, the control data for the motor (Mt) when constant speed control is not performed are the forward/reverse signal (F/R) and drive signal (D/R).
S) is output as a combination.

For example, the control data for forward braking during return is (FD), and the control data for regenerative braking during return is (FS).

The FG interrupt process is generated by the fall (or rise) of an encoder pulse corresponding to the rotation speed of the scan motor (Ml>), and mainly calculates the time (M'rON) for turning on the scan motor (Ml). That is, as shown in FIG. 8, the time from the previous FG interrupt (F"
'G□) and determines whether there is a TON correction request or not in step O-○. T ON
The correction request is set to 1'' from the time when the exposure switch (SW-E) is turned on until the end of scanning, and if "NO", proceed to step 07, or if "Y" is J, proceed to step ○Em. It is determined whether (Δi?G, >0).

“If YESJ, the pulse interval (FG) is the set value (F
C□) and the scanning speed of the scanning system (1) is slow, so in step
) is added to the basic time (TON). If Step ○IE) in OfS is "NO", the scanning speed is fast, so a predetermined value (1 in this embodiment) is subtracted from the reference time (TON) in Step ○g.

Next, in step (-), it is determined whether (1ΔFCI≦K). Difference (Δt'
G) is a constant that determines the tolerance range of (1Δ1゛Gl)
If it exceeds the allowable range, it is determined as "NO", and in step (1), (Δ1
rG)0), and if it is "YIζS", set the main motor (Ml') to full on in step GZEE), output drive ON data in step 〒, and return to the main routine. . Step (possible) D is “
If NO, set to full off at step ○, output drive 0 data at step ○■〒D, and return to the main routine.

On the other hand, if 'YS notation (1Δl''Gl) is within the allowable range, it is determined as l'-YESJ at itl notation step GD,
At the end of step ○, the calculation formula (TON -1-A (
1”G-FGO)) and calculate the motor on time (MT
ON), outputs drive ON data at step C and ■D, and returns to the main routine.

(Left margin) Figure 9 shows the subroutine (HOME). This means that if the scanning system (1) is not at the home position at the start of scanning, the main motor (M□) is reversed and the scanning system (1) is not at the home position. EJfl
This is a subroutine that returns the + to its home position.

That is, in step [phase], the home switch (SW-1 (
) is off, and if "NO", the scanning system (1
) has returned to its home position by one position, so
Return to the main routine immediately. [If YESJ, the constant linear system (1) is far from the home position, so first, in step ■, the control data (RD) is used to drive the motor (Ml) in reverse, and in step @, the constant speed control data ( 1゛'Go), ('l'ON), (A) are set, and (RD), (R5
), the subroutine (FG
WA I T ) is executed, and constant speed control is performed.

Here, after confirming that the scanning system (1) turns on the home switch (SW-, 1(), that is, the scanning system (1) has returned to the home position in step ①, step [phase] f) Execute the interrupt disable routine (MCQ, lF), turn off the constant speed control, set the step [phase] 1 iron stop timer, and move on to the stop operation (fixed position control). That is, step @ Set the control data to (1 = "D") to drive the motor (M After the stop timer expires, the scan motor (Ml) is stopped by setting the control data to (R5) in step (I(9)), and the process returns to the main routine.

The subroutine (FGWA I T ), as shown in Figure 1o, allows one interrupt for constant speed control, and waits for the encoder pulse to start at step [phase], and then interrupts TON at step @. Set the correction request to “0”.

Allow interrupt at step @=JL, return to main routine.

The subroutine (MCOFF) is for ending constant speed control as shown in Fig. 11. After prohibiting interrupts in step @, it stops the motor (M□) as a control booter (R5) in step Q◇. , return to the main routine.

FIG. 12 shows a subroutine (SCAN:A).

(SCAN: A) is the actual copy scan (SC
This is an execution routine for the preparatory scan (which is carried out prior to AN:B), and the copy scan (SCAN
:B) The motor on time (MTON) data used in step B) is set.

First, in step (2), (F D ) is set in the control data to drive the motor (M□) in normal rotation. This full-power normal rotation drive continues until the first encoder pulse input is received, helping the scanning system (1) to start up.

Then, the RAM area of the microcomputer (3)
As this drive ON data (RD), drive 01=
'(FS) is set as F data. Next, at step 0, the braking delay counter ('l
'M) is set to initial data, and constant speed control data (17Go), ('l
-0N) and (A), and set the fixed position shift amount (1-IP S FT) in step 0. This (I
ll) S FT) is a value indicating the distance from the turning-on rising edge of the home switch (SW-H) to the actual stop operation, and is counted by the delay counter from the turning-on rising edge of the home switch (5W-11). When the count ends, it moves to the stop operation. At the same time, in step (2), the correction value of the counter calculated from the scanning scan size in the copy scan (SCAN: 13) is set as (CT).

This is because the preliminary scan (SCAN: A) is set to the minimum scan size and is usually shorter than the actual copy scan (SCAN: B), and the braking start timing changes depending on the scan → noise. This is to correct the counter measurement value upon return after (SCAN:A).

Next, at step 0, the subroutine (1・GWA 11”
) and waits for the first encoder pulse input to start constant speed control. Then, in step [phase], wait until the exposure switch (SW-E) is turned on for scanning system (1) 1, and when it is confirmed that the exposure switch (SW-E) is turned on, step 0
1 Set the trowel counter to 1 for the preliminary scan size, set the 1゛ON correction request to “1” in step 0,
Wait for the reference time (TON) to converge. The exposure switch (
Wait in step q for the counter that started when SW-E) is turned on to count the number of pulses set for the scan size (SW-E), and when finished, process the subroutine (MCOFF) in step qψ, disable interrupts, and enter the settings. Speed control ends. The reference time ('I'ON) corrected in this preliminary scan (SCAN:A) is saved in the register (TONR) at the step (already), and thereafter this data is used for exposure in the copy scan (SCAN:B). Switch (SW-
One constant speed control is used until E) is turned on.

FIG. 13 shows the subroutine (SCAN:B).

(SCAN:B) is the preparatory scan (SCAN:A)
This is a copy scan execution routine that is performed after.

First, step (scan (SCAN:A) attached to φ)
Similarly to step [phase], the motor (M□) is driven in normal rotation and the drive ON-OFF data is set, and the braking delay counter ('rM) at the time of return is corrected in step . That is, the constant speed control distance 111t (CT) and the constant set value (CK) measured at the time of return, which will be explained below.
and the difference is added to the data (TM) set last time (preliminary scan). Next, step @f clears the counter in order to measure the braking timing of the next return of the iron. At the same time, in step 0, the constant speed control data (IjGo
), (A), and in step [phase], the reference time (TON
) is restored.

Next, at step 0, the subroutine (F GWA V[)
is processed and constant speed control is started. And step O
Wait for the exposure switch (SW-E) or scanning system (1) to be turned on, and when it is turned on, the counter is set to the actual copy scan size in step O. ) 1 iron “1” ON correction request “1”
" and start correcting the reference time ('1" ON). In step [phase], the counter that starts when the exposure switch (SW-E) is turned on counts the number of pulses set for the copy scan size, and when it is finished, the subroutine (MCOFF) is processed in step Cψ.
Interrupts are disabled and constant speed control ends.

FIG. 14 shows a subroutine (RETURN).

First, in step (2), control data (D) is set to drive the motor (Ml) in reverse at full power, and in step (2), constant speed control data during scanning is saved in a register. Next, check whether the power is on in step @, and then press the brake switch (S) in step
Wait until W-B) is turned on in the travel system (1). When this brake switch (SW-B) is turned on, a braking delay counter (TM) is started at step (already), and the braking delay counter (TM) is started at step (2), and while checking whether the power is on or not at step (2), the braking delay counter (TM) is terminated at step (2). This counter (T
The setting value of M) is the value of the initial data set in step (3) if the return is after the Yabi Sugiyan, and the value corrected in steps (○) if the return is after the subsequent copy scan.

When it is confirmed that the power is turned off in steps q and ■ above,
During this time, the scanning system (1) is in the process of returning, so it immediately sets the error flag in step (already) and executes the routine in step (2).
This is performed by the circuit shown in FIG. The circuit configuration and operation will be described later.

When the counter (TM,) ends, step ('z5
Set (F S ) in the control data at , apply regenerative braking to the scan motor (town), set a constant speed at step Q9, and set the control data at step φQ + iron shoe system (1).
Wait until the speed of is reduced to this set speed.

When this deceleration is detected, step ■1 sets (FD) in the iron control data, applies forward rotation brake to the motor (Ml), and sets the first speed to release the brake in step @. .

The rotation speed of the above process 1 trowel motor (Ml), that is, the return speed of the scanning system (1) is decelerated, and during deceleration the step (
If it is determined that the speed is faster than the first speed in step (b), the home switch (SW-1-1) is
By detecting the rising edge of the ON state, a brake correction measurement counter (C'l') is set in step n, and the first
Wait until you slow down below the speed to count.

When this deceleration is finished, it is checked in the step smoker whether or not error 7 lag is set. If it is set, the power is off (see step @, [Yes]), so the subroutine ( MCOFF), interrupts are disabled, step (boiled) waits for the power to be turned on, and returns to the start. However, except for momentary power interruptions, when the power is normally turned off, the microcomputer ( 3) is reset.Conversely.

A power off signal is issued before the time reset signal until the end of this deceleration operation. If the time from this power-off signal to the reset signal is short, the forced braking time is short, deceleration is not sufficiently achieved, and the speed of entry to the return side increases. Therefore, the reset signal is delayed by a capacitor (C2) (see FIG. 15, described later).

If the error flag is not set, it is determined whether or not the steering has been performed, and if it is on, the brake correction measurement counter (CT) is set to the fixed position i (Hl'
The count value from the home switch (S FT), that is, the count value from the home switch (S
W-1-1) is set by subtracting the distance that the scanning system (1) has moved since turning on. In other words, the home switch (
If the distance from the time SW-tI) is turned on to the deceleration path r is longer than the fixed position shifter l-11L (old I'S FT), the counter (CT) will be positive and the next braking timing will be at this time. slower than Conversely, if the distance to the end of deceleration is longer than the fixed position shift amount (upsF'r), the counter (c) becomes negative f, and the next braking timing is corrected to be earlier.

When the processing in step ■ is performed, the subroutine (MCOFF) is processed in step ■, and separation is prohibited.
Performs fixed position control. That is, the subroutine (ooME
) The same control as φ~(yu) is performed, and the transport system (
1) stops at the home position.

On the other hand, if the home switch (SW-41) is not turned on at the end of deceleration, the control data (
Set R5) to free the motor (M□).

In step [phase], a counter (CT) is set, and in step 2, a second speed for performing reverse constant speed control is set. The return of the scanning system (1) here is inertial movement, and the home switch (SW-
14) By detecting the rising edge of the ON signal, the distance traveled from the end of deceleration to this point is set in the counter (CT) in step '■.

Next, in step @, the fixed position is shifted (IPSFT)
is set, and in step [YES] it is determined whether the scanning system (1) has decelerated to the second speed or not. If the scanning system (1) has not been decelerated, the routines of steps 0, 2, and @b are repeated until the counter finishes. When it is determined in step [phase] that the second speed has been reached, constant reverse speed control data at the time of return is set in step φ, and constant reverse speed control is performed. That is, step ■Φ1 iron 117IJ control data (RD)
Set one motor and reverse the motor (M□),
Drive ON data (RD) and drive OF data are set, and in step ■■ the subroutine (FG
WA 1. T). And step 6)
Wait for the counter to finish, and then execute the subroutine (
MCOFF) and performs fixed position control.

Here, the power supply circuit shown in FIG. 15 will be explained. This power supply circuit is configured to delay the reset signal to the microcomputer (3) and apply braking to the scanning system (1) even if the power is turned off when the fixed distribution system (1) returns. There is.

That is, the AC power supply (4) is connected to the constant voltage stabilizing circuit (2), the terminal (T□) and the terminal (1' 2) via the rectifier circuit (2I).
and the connection point between the -power output side of the rectifier circuit c21) and the constant voltage stabilizing circuit (2), and the other output side and the terminal (
A capacitor (C□) and a resistor (R
5) and (R6) are connected in parallel. Comparator (goods)
The input side is connected to the connection point of the resistors (tt5) and (R6) and a grounded power source (Eo), and the output side is connected to the power signal terminal (T4). In addition, the connection point between the constant voltage stabilizing circuit and the terminal ('1"1) and the rectifier circuit f21+
A capacitor (C2) and resistors (R7) and (R8) are connected in parallel between the connection point between the other output side and the terminal (T2). The input side of the other comparator (24) is connected to the connection point of resistors (R7) and (R8) and the grounded power supply (E'2).
) is connected, and the output side is connected to the reset signal terminal (T2).

When the power is turned on, one DC current is supplied from the terminal ('r□) to the scan motor (M□), and the power signal from the comparator (23) is "H", and the comparator (211) also outputs a reset signal of 11", and the capacitor (C2) accumulates this voltage. Normally, the scanning system (1) is driven in this state, but the power supply
If the terminal (T1) and the comparator (
24) is supplied with the current accumulated in the capacitor (C2), and after a certain time delay, the reset signal on the comparator side is switched to "L".

Due to the existence of this delay time (1), sufficient braking can be applied to the scanning system (1), and a situation such as the scanning system (1) colliding with a stopper can be avoided.

That is, in the above embodiment, since the scanning system (1) is inertially moved when transitioning from the braking state to constant speed control when the scanning system (1) returns, the transition to the constant speed control state is difficult. It becomes extremely smooth.

In addition, in this embodiment, the setting value (TMn+□, n: :z, number of scans) of the braking delay counter ('rM), which determines the timing to apply one brake when the running f system (1) returns, is One measurement during constant speed control of previous return (
The optimum braking timing is obtained by sequentially correcting the data (CTo) indicating the moving distance of the scanning system (1) during constant speed control performed in steps @, ■, ■) (step ■). Expressed in a control equation, TMn+CTn This correction acts on TMn+ so that (CT,=O).

In other words, when (CT > 0), the braking timing is short, so the first count setting value (T
Mo+, ) is corrected to be larger than the previous count setting ta (l darkness n). Inversely, when (CTn<O), the braking timing is delayed, so the next count setting value (1Mn+1) is corrected to be smaller than I'+i1 time count setting value (-rMn)-. That is, in any case, the next count setting value (TM, +1) is (
It approaches a constant value (-1'M) which is c'ro20).

Effects As is clear from the above explanation, the present invention provides, during the backward movement of the scanning system that is driven reciprocally, the scanning f system is driven one direction in the return direction from the forward movement final position r, and then braking is applied to decelerate the movement. When the speed of the scanning system reaches a first predetermined speed, the braking force is released, the fixed yarn is inertially moved, and the speed of the scanning system is lowered to a second r value lower than the first speed. When the predetermined speed is reached, constant speed control is performed at this second speed to return to the home position, so of course the position control for returning the scanning system to the home position can be performed on the old 1st page.
By intervening inertial movement, the transition from the braking state to the constant speed control state becomes extremely smooth, and vibrations in the scanning system can be extremely reduced.

[Brief explanation of drawings]

The drawing shows an embodiment of the deceleration control method according to the present invention, and f
Fig. FJ1 is a perspective view of the red-scanning system, Fig. 2 is a block diagram of the cape control means, Fig. 3 is a motor t1M control circuit diagram, Fig. 4 is a graph showing speed changes during scanning and return of the scanning system, Fig. 5 The figure is a pulse waveform diagram for explaining constant speed control, Figures 6 to 14 are flowcharts of the 11 control means, Figure 15 is a power supply circuit diagram, and Figure 16 is a voltage waveform and signal waveform of this power supply circuit. FIG. (1)...Scanning system, (2)...Encoder, (3)
... Microcomputer, (4) ... Driver circuit, (Ml) ... Scan motor, (SW-14)
... Home switch (SW-B) ... Brake switch. Patent application Person: Minolta Camera Co., Ltd. Representative: Mr. Masuji, above, and two other persons Figure 3, Section 5, G, Figure 15, Figure 16; ET' 1 c, Figure 6, Figure 8, Figure 9. Figure 10 Figure 11 Figure 12 @ Figure 13 Figure 4

Claims (1)

[Claims] 1. During the backward movement of the scanning system that is driven reciprocally, the scanning system is driven from the forward movement end position toward the return direction, and then braking is applied to decelerate the scanning system so that the speed of the scanning system reaches the first predetermined speed. When the speed of the scanning system reaches a second predetermined speed lower than the first speed, constant speed control is performed at this second speed. Scanning system deceleration control method characterized by returning to home position