JPS60262147A - Scanning device - Google Patents

Abstract

PURPOSE:To allow a scanning system to move back and stop securely and speedily by comparing a detected speed at a stored reference speed and correcting and determining braking timing, or determining current braking timing on the basis of data on the last braking timing selectively during the backward movement of the scanning system. CONSTITUTION:The scanning system 1 having a lighting system is scanned forth by a DC motor 2 in a direction A at a high speed, and also returned in the opposite direction of A while accelerated through the reversing of the motor 2. An encoder 3 detects the rotating speed of the motor 2 and the position of the scanning system 1 and makes a comparison with the 1st reference speed which is stored in an unshown control part corresponding to the position, thereby applying a brake 5 when the speed exceeds the reference speed. The motion of the scanning system during this braking operation is measured and stored in the control part as the 2nd reference data for correcting the timing of next braking. The 1st or 2nd reference data is selected according to scanning conditions. Consequently, the copy necessary time is shortened by the simple constitution according to various conditions of the size of a copy form, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a scanning device in which a scanning system is reciprocated by a DC motor;
For example, the present invention relates to a scanning device for exposing a document image onto a photoreceptor 2 with a slit in an electrophotographic copying machine.

2. Description of the Related Art In general, an image scanning system in an electrophotographic copying machine uses various scanning modes, i.e., 6°, 6°, It is necessary to control the backward movement of the scanning device and 7 so that the scanning system always stops at a fixed position (home position) for each type of scanning mode. It is necessary to provide a sufficient preliminary movement distance for the purpose of standing up at the time, and this is because the scanning device becomes larger and the time required for reciprocating movement increases.

As mentioned above, in order to achieve the return of the scanning system to the normal position, constant speed control was performed throughout the entire return movement (Japanese Patent Laid-Open No. 56
= No. 83770). However, as the number of scanning modes increases, the control and configuration become more complicated.

Unless a complicated control method is adopted as in JP-A No. 56-83770, when the forward movement system is reversed,
A possible method would be to accelerate the drive and apply braking at a predetermined timing. This method simplifies control because only a portion of the backward motion, such as deciding when to brake, is required.

As for how to obtain the braking timing, there is a proposal to provide a fixed switch in the scanning path and to set the braking timing when this switch is turned on by the scanning system. However, in the case of a copying machine with a variable scanning length, a switch must be provided according to the maximum scanning length, and this may result in a long return time (this disadvantage) when copying with a short scanning length.

As a proposal to solve this problem, Japanese Patent Application Laid-Open No. 59-7357 proposes storing a reference speed at each position of the scanning system during braking, and setting the braking timing at the time when the speed during backward motion reaches or exceeds this speed. This shows how to do this. However, because the accelerating force and braking force of the motor and driver element change due to temperature rise due to continuous use, etc., it may not be possible to stop the motor or driver element accurately enough at the forward movement start position where the motor or driver element should be stopped.

On the other hand, in the acceleration braking method described in -, a proposal for accurately stopping the forward movement start position was published in Japanese Patent Application Laid-Open No. 59-2.
No. 9238 shows that when the speed of the scanning system reaches a sufficiently low predetermined speed due to braking, constant speed control is performed at that predetermined speed from the forward movement start position, while The speed control distance is measured, and the next braking timing is corrected using this distance so that it is shorter than the distance. Therefore, since constant speed control is performed before stopping, accurate fixed position control can be performed, and the constant speed control distance becomes shorter as the copying process continues under the same conditions, making continuous copying more efficient.

However, since the previous measurement data is not available during the first back-and-forth movement, this product performs a test back-and-forth movement and measures the data before the actual copying, and uses this data for the actual copying. Since a test reciprocating motion is performed every time the scanning conditions change, it is inefficient when copying each sheet by changing the scanning conditions.

As described above, all of the conventionally proposed methods have advantages and disadvantages, and accurate and simple control cannot be performed under any scanning conditions.

In view of these points, the present invention can always start braking at an appropriate timing for any scanning conditions and conditions with a simple configuration and control method, and can securely return the scanning system to its normal position and return to its normal position. The aim is to shorten the

In the present invention, the DC motor is controlled at a constant speed when the scanning system is moving forward, but when it is moving backward, it is first accelerated and driven, and when a predetermined braking timing is reached, the motor is braked and stopped at the forward movement starting position. The object of the present invention is a scanning device that reciprocates a scanning system,
The following is provided as a means of solving problems.

ΦDetection means for detecting the speed at each position of the scanning system; 6 means for storing the basic speed at each position of the scanning system during braking; ・Memorization of the detected speed of the detection means and 1. A first braking means that compares the reference speed of the means and starts braking when the detected speed becomes less than the reference speed as the braking timing; Measures the movement of the scanning system during braking and collects this measurement data. a second braking means that corrects the braking timing during the next backward movement according to the following; - a selection means that selects either the first or second braking means according to the scanning conditions;

,,f'""" As described in the previous section, the present invention has two means for determining the braking timing, and these can be selectively used depending on the scanning conditions.

The first braking means determines the braking timing by comparing the stored reference speed with the detected speed, and can be said to be a general timing determining means.

On the other hand, the second braking means corrects the next braking timing based on the measurement data from the previous braking, and can be said to be a means for finely adjusting the timing for the purpose of accurately returning to the home position and shortening the return movement time.

There are various ways of thinking about how to select both means. In the embodiment, when the magnification or paper size is changed, the first scanning is performed using the first braking means, and from the second time onwards, the second scanning is performed. The braking method is selected accordingly. This uses the factors that change the scan length as they are, but even if these factors change, the scan length may not change. Since the scanning length is a factor that determines the braking timing, the scanning length may be calculated from these factors and the first braking means may be selected only when the scanning length has changed. Incidentally, the paper →noise indicates the size of the copy paper, but in a copying machine or the like where the scanning length is determined based on the size of the document, the size of the document may be used.

Another way of thinking is to start the copying machine from a standby state. This method can be said to be suitable for scanning devices such as facsimile machines whose scanning conditions do not change much.

Embodiment Before explaining the embodiment in detail, the principle of the embodiment will be explained using FIG.

As shown in FIG. 1, the embodiment consists of three phases.

In phase 1, when the power is turned on, only the scanning system is reciprocated as a test, and the position and speed during braking are read into memory as 8-speed deceleration data, and the take stored here is used in the next phase 2. .

Phase 2 is to determine the braking timing by comparing the target q-deceleration data with the detected speed during acceleration.

In the next phase 3, the next braking timing is corrected based on the measurement taken during the previous backward motion.

If there is a mode change, the process returns to phase 2, and if the mode is the same, copying continues in phase 3. Note that the mode indicates each scanning state obtained by a combination of scanning conditions.

In this embodiment, the marker deceleration data used in Phase 2 is obtained in the test scan of Phase 1, or this data may be stored in a nonvolatile memory, for example. However, the method of obtaining data by sampling each time the power is input can be said to be a flexible control method that can accommodate changes over time and adjustment of the device.

Hereinafter, to specifically explain the embodiment, in FIG. 2,
(1) is a scanning system including an illumination system, and (2) is a DC motor (
The scanning system (1) is driven by this DC motor (scan motor).
2), reciprocating movement, that is, forward movement in the direction of arrow A) (lower PL,
(hereinafter referred to as "scanning"), and moving back in the opposite direction (hereinafter referred to as "return").

(3) is an encoder composed of Hall elements,
It is installed on the rotating shaft of the DC motor (2) and generates a pulse signal proportional to the number of rotations of the DC motor (2). ) can be detected.

(4) is a home switch, which detects whether the scanning system (1) is at the home position (scan start position); it emits an on signal when it is at the home position; otherwise it emits an off signal. emanate. When it is detected by this detection signal that the scanning system (1) is not at the home position at the start of scanning, control is performed to return the scanning system (1) to the home position. (5) is a brake switch that detects when the scanning system (1) reaches a predetermined position during return, and is used as a reference position detection means for the braking start timing during return movement in the flowchart described later.

FIG. 3 is a block diagram of a control circuit for controlling the movement of the scanning system, and (20) is a microcomputer for controlling the scanning system. In addition to the scanning system, the copying machine has various control pairs, or these are controlled by a micro combi coater (not shown), hereinafter referred to as a mask.

A microcomputer (2(1)) is a central processing unit (C'PU), a read-only memory (
ROM), random access memory (RAM), human output port (Ilo), counter (Tf), and timer register (Tw), and from the mask, control request signals (MAG), (SCAN), (SIZI! ;) is input. A signal (MAG) indicates the selected magnification, and this signal sets the scanning speed. Signal (SCAN)
"1" indicates forward movement, and °°0" indicates backward movement. Signal 5IZE indicates the selected copy paper size. Other inputs include position detectors (4) (5) of the scanning system. ).

Furthermore, as outputs, a motor drive signal FD+ and a forward/reverse signal (F) are outputted to the switching circuit (21), thereby controlling the DC motor (2).

The (CPU) has two interrupt terminals, and an encoder pulse obtained by shaping the output of the encoder (3) by a waveform shaping circuit (22) is input to one terminal. The other terminal is connected to a timer register (Tw), and a timer value (1, "w), which will be explained in the flowchart described later, is set in the timer register (T'w).

The timer register (Tw) compares this timer value (Tw) with the reference time (Tf) of the counter (Tf) that counts the reference pulses of the external base thread oscillator (23), and if the two match, the (CPU) Input interrupt signal.

FIG. 4 shows a specific example of the switching circuit (21).

The DC power supply (E) is a bridge-connected transistor (T
DC motor (2) via r1) ~ (Tr4)
diodes (D+) to (D4) or each transistor ('I) to form a bypass for back electromotive force.
-, z+) to (T'r4) are connected in parallel.

The input terminal (9a) is for inputting either the forward rotation signal "LI'" or the reverse rotation signal "I-";
It is connected to the input side of the AND gate (AND2) and the transistor (Tr:
+) is connected to the base. The other input terminal (9b) is to which the ON signal "I-■"' and the OFF signal "L" are input, and the AND gate (A, ND l),
(AND 2 ) is connected to the input side.

In addition, an AND gate (AND2) is connected to the base of the output side 4-J) transistor (Trz) of the AND gate (AND+).
) is connected to the base of the transistor (Tr4).

In the above configuration, in the forward rotation mode (FD), the transistor (Tr3) is connected to the input terminal (9a) or 'I-1'.
turns on, and when the input terminal (9b) is “H”, the AND gate (AND+) becomes “H” and the transistor (Trz)
power) is turned on, current flows in the direction of arrow (a), and motor (2
) Force S rotates forward. Also, when in reverse mode (RD),
Switch the input terminal (9a) to "L", turn on the transistor (D-rl), and input terminal (9b)'l-1
The AND gate (AND2) becomes 'H' and the transistor (T'r4) turns on, current flows in the direction of the arrow (■), and the motor (2) rotates in reverse.

On the other hand, in the brake mode (FS), the input terminal (9a) is switched to "H" and the input terminal (9b) is switched to "L" in the reverse rotation state, and only the transistor (Tra) is turned on.

In this case, the current to the motor (2) is cut off, or a back electromotive force in the direction of the arrow (a+force) is generated, which attempts to reverse the rotation of the motor (2). This back electromotive voltage is caused by the transistor (
It flows through Tr3)+motor (2) and diode (D]), and brakes against reverse rotation of motor (2), that is, regenerative braking is applied.

In addition, diodes (D+'), (Dz), (
Ds), (D4) cut the back electromotive force generated during forward rotation or when switching modes, and the transistors (1-:r+), ('T'r2), (1''r3), (
Prevents abnormal voltage from being applied to Tr4).

Next, an overview of the control will be described.

cormorant. During the return of this test scan, standard deceleration data to be used in phase 2 is sampled.

FIG. 5 shows the speed change during return.

・1: At the start of recovery, when the control force of the DC motor (2) is switched to the reverse mode, the electric current is connected directly to the motor (2). At this time, the acceleration of the motor (2) decreases in proportion to the rotation speed due to the back electromotive force generated by the rotation of the motor (2), assuming that there is no change in the power supply (even load).
As shown in Fig. 5, the rotation speed of the scanning system (1) decreases from the start of recovery, and after reaching zero, it accelerates in the direction of recovery (if the reverse/on mode continues). As the rotation speed of the motor (2) increases, the back electromotive force also increases, so the acceleration also decreases and approaches a certain value as shown by the dotted line (X) in FIG.

During the return of the test scan, when the brake switch is detected, a brake signal is output to the motor control circuit (7),
Braking is applied by the back electromotive force generated by the rotation of the motor (2). The acceleration at this time is that the back electromotive velocity approaches zero as shown by the curve (Yl) in Figure 5.However, due to the friction of the sliding surface of the scanning system (1), a small constant negative acceleration As the speed decreases, it decelerates linearly and stops.In practice, the scanning system (1) returns to the Baum position before stopping in this way, and is forced to stop by a tamper etc. I am made to do so.

In the second test scan, the relationship between the position and speed of the scanning system (1) during deceleration after the brake signal as shown in FIG. 5 is stored in a random access memory (RAM). The installation position of the brake switch (5) is set so that the speed when the scanning system (1) returns to the home position ζ is the optimum speed with respect to the time constant of the damper and the like. In addition, in order to use the data obtained in the test scan as a reference for all actual scans, the scanning distance in this test scan should be set at the position where the maximum speed occurs in all scans or after the brake switch (5). The position is set to maximum.

Next, phase 2 will be described. Phase 2 is performed four times during the actual scan, and braking is performed at timings predicted based on the standard deceleration data sampled in phase J. When the return starts, the motor is turned on in reverse and returns while accelerating, similar to the test scan. after that,
When a brake switch is detected, unlike a test scan, braking is performed but the actual return state is compared with standard deceleration data. When the deceleration data reaches the vicinity of the standard deceleration data, the braking start timing is determined. Further, the distance from the brake switch at this time is stored as the predicted timing (DELAV) in phase 2, and used in phase 3.

FIG. 6 shows the change in the scanning system when braking is applied in this manner. Note that the scan length of the test scan is set to be the same as the actual scan length when copying from full size to noise.

Phase 3 is based on the predicted timing (DE
Fine adjustment is made to the optimum timing based on the actual braking results.

FIGS. 7 and 8 are graphs showing speed changes during backward movement of the scanning system, and the broken line shows speed changes during optimal deceleration, which is the objective of control. After the scan is completed, the scanning system starts backward movement, returns without accelerating, and starts braking after a certain delay (DELAY) after turning on the brake switch. Then, after sufficiently decelerating, it returns to the home position, comes into contact with a damper material, etc., and stops. Further, the scanning system starts the next forward movement as necessary.

During the return movement, the speed at the home position (VIh
ome) is important. Because (VIhome)
If the speed is too early, stable deceleration will not be achieved by the tampering material, and the device will stop moving away from the home position, or abnormal vibrations will occur during the next forward movement, making it impossible to obtain a good image. On the other hand, if it is too late, the time required for return movement will be longer.
This is because the copy speed becomes low.

Therefore, in phase 3, the velocity at the home position of the scanning system (
V'hOme) is always controlled to a predetermined speed (V, home) even in the scanning mode.

FIG. 7 is an example of correction by distance measurement. In other words, as shown by the solid line, apply the scanning system or brake switch ('Ayu-Offika,; -*i1.li (DELAY)g□□1j).Then, apply the scanning system or the brake switch to the front of the home position. Assume that the vehicle decelerates to a predetermined speed (Vhome) and reaches the home position at the speed (V'home) while further decelerating.

At this time, the distance (ΔX) from the predetermined speed (vhome) position to the home position is measured, and this (ΔX) is calculated as (DE
LAY) and corrected (1)] 1L at the next return movement.
AY), the speed at the home position becomes a predetermined speed (Vhome), as shown by the broken line.

If the measured speed (VIhome) is faster than the predetermined speed (vhome) and (ΔX<0), is it possible to correct it by distance measurement?In general, in order to contact the damper immediately, (ΔX) should be increased. All I can do is take it.

Therefore, as shown in Figure 8, the velocity at the home position (V
'home). Basically, the speed at the home position (v111']Ome) is changed to a predetermined speed (
The distance (ΔX) until the vehicle is decelerated to Vhome) is calculated, and (DELAY) is corrected.

(ΔX) is the acceleration near the home position (approximating that al is constant), then the measured velocity at the home position (V ′
home), -Δx=f(VIhome)=-(V'home)
”/2a...Equation (1) is obtained.The correction by f(V'hOme) ic is [vI
Although it is possible that home<Vhome), (VI
When the difference between home) and (Vhome) increases,
Since (a) also changes, calculation becomes complicated.

The first speed measurement near the home position is performed in Phase 2, and based on this measurement result, the predicted timing (DELA) in Phase 2 is determined using the method shown in Figure 7 or 8.
Y), and in the case of continuous copying, all subsequent braking timings are determined in this phase 3.

Figures 9,] O, and 11 are microcomputer (
20), and FIG. 9 shows the main routine, the Ito diagram or the external interrupt (INT-1',) routine by the encoder pulse, and FIG. 11 the timer interrupt (Tw) by the timer register (Tw). IN
T-+T') routine is shown.

First, the main routine shown in FIG. 9 will be explained.

When a reset is applied, a phase 1 test scan is performed. First, in step (]S), the motor drive signal CD) is
0".D=Q corresponds to the state of the input terminal (9b) or 'L°' in the switching circuit shown in Fig. 4, and D=1 corresponds to the state of "H".
Corresponds to the state ″′.

Next, in step (2S), parameters are initialized. As an initial setting, set the braking timing (DELAY) to O.
The TEST flag indicating the phase] is set ("1"). Furthermore, the test scanning mode (real size, A3 size) is set.

LOCK is set unconditionally on test scans to indicate that Phase 2 is complete.

Next, in step (4S), the reference encoder pulse interval (1”S) is used to control the scanning speed corresponding to the copying magnification.
Calculate. This reference encoder pulse interval σS) is the encoder pulse interval at the same magnification (T
o) by the copying magnification MC. In step (5S), a scan timer L is used to determine the scan length.
Perform the calculation.

The scanning length is the distance Lc from the scanning start position to the leading edge of the document. It is determined by the sum of LO and original scanning length -Mc-.

Here, the constant is used to convert into the number of encoder pulses. Then, in step (6S), it is determined whether the scan timer L is larger than the maximum scanning length "'-MAX (converted to the number of encoder pulses). This is because if reduction is selected, the scan length or scannable range will be exceeded.

Therefore, if YES in step (6S), the maximum scan length "I-" is set in scan timer I- in step (7S).
'MAX is set to restrict the scanning range to 1hjq. If NO, skip step (7S) and proceed to the next step (8S).
August is here.

In step (8S), the W reversal signal fFl is set to "1".

1'-1 is the switching circuit shown in Figure 5, and the input terminal ((]
a) corresponds to the '11'' (7) state, and F=0 corresponds to the L'' state.Subsequently, in step (9S), the motor drive signal, 1.
- No. (1) The scanning system (1) starts to move forward by turning l to °pi.

In step (1019), a counter (SYN) for synchronizing the encoder pulse and the interrupt routine is set to 2'', and the processing mode in the interrupt routine is set to constant speed control mode, that is, (M( B) Set E) to ' 1 ', and perform the following steps (], 1.
8) Enable interrupts. Control of the scanning system (1) from permission of this interrupt is processed by the interrupt routine, and the main routine waits at step (128) until the l-10ME switch is turned off.

This is done to prevent variations in scan length due to variations in scan start positions. HOM at step (128)
When the E switch is turned off, the scan timer is made negative (step (L3S)). As a result, the timer is incremented in synchronization with the encoder pulse by an external interrupt processing routine (INT-E) to be described later. Then, when the scan timer L reaches zero, the scan ends. (Step (14s)).

Next, in step (158), the speed measurement mode is set, that is, (MODJζ) is set to "°O", and step (1
The motor drive signal is turned off at step 68), and the reversal signal is set to reverse (F=0) at step (1, 78) for backward movement. This is because synchronization with the encoder pulse must be re-established during interrupt processing, resulting in a delay in control. When the drive is turned on, the scanning system (1) starts returning to the home position. At this time, the central processing unit)
(CPU) does not perform any control, so acceleration continues.

After this, in step (19S), brake switch (5
) is turned on, in other words, the scanning system (1) remains in a standby state until the scanning system (1) returns to the position of the flake switch (5), which is the basic position for deceleration control. When the flake switch (5) is turned on ("1"), the counter (PO5) fc that measures the amount of movement of the scanning system (1) in step (20S) is activated at the current deceleration control timing (D]!, LA,... ,
The complement of Y) is set, and during the processing of the external interrupt routine (INT-E), the encoder pulse counting mode is set, that is, (λ401)F,) is set to "3"'. External interrupt routine (INT-1') c. Adds "1" to the encode pulse and to the counter (pos). Therefore, the scanning system (1) is connected to the brake switch (
After turning off 5) and moving by (1) ELAY), the counter (r”os) becomes zero. Step (21,
8) to detect this and an external interrupt routine (INT
-E) timing check mode (MOI) E=
2) (steer knob (228)), and in the test scan, the -7OCK flag is set, so the reverse drive is turned off (D=O) by skipping step (23S) and stepping (248>). L, step (25S) sets the forward/reverse rotation signal to forward rotation (]"-1). This causes the motor (2
) is applied with regenerative flaking, and the scanning thread (1) starts decelerating. Then, in step (268), the flag FAST for phase 3 is set to 0''.

After this, in the main routine, the system enters a standby state until the scanning system returns to the home position (step (278)).
. During this period, standard deceleration data is sampled (routine INT-).When returning to the home position, interrupts are prohibited in step (28s) and the return operation is completed.After that, in step (33113) It is in a standby state until an actual scan request is detected (,5CAN=1).

The above is the main routine processing during test scanning.

Next, before we explain the actual scanning using the 5CAN signal, we will start when an encoder pulse or external interrupt terminal ζ is input! External interrupt processing routine (INT-
1i) (.Lucia (I N1-
-E) Lt, speed measurement mode (MODE = O), constant speed control mode (Mol) F, = 1), timing check mode (MODE = 2) and pulse counting mode (
Four types of processing modes are set: MODF,=3). Furthermore, in the timing check mode, processing is divided into three phases based on two flags TF, ST and LOCK+.

Among these functions, the constant speed control mode (MoD = -t), timing check mode (MODE = 2) phase 1, and pulse counting mode (MODE = 3) are ) will be explained.

4 When an interrupt occurs in Fig. 10, the step knob (418) first stores the value (Tf) of the counter (Tf), which is the reference time in the microcomputer (20), in a predetermined area of the random access memory (RAM). Copy the register (TO) to be set. Therefore, the register (1"C) is the current pulse generation time (1"C) of the encoder (2).
).

Next, in step (4, 23) the counter (SYNC)
The value of is determined, and if it is other than zero, "1" is subtracted from the count value in step (438). This counter (SYN
C) is for synchronizing the encoder pulse and the interrupt routine, and in order to increase the pulse 7 interval of encoder (3), at least two encoder pulse intervals are required.
This is set to invalidate the calculation result of the pulse interval between them. In this embodiment, the initial value of the counter (SYNC) is set to "2" in order to ignore even the first pulse.

In step C448), the pulse interval (Ti) of the encoder (3) is determined. This calculation is performed based on the current encoder pulse generation time ('T' c ) set in step (4is).
) and the previous encoder pulse generation time (Tp). The previous encoder pulse generation time (Tp) is stored in a register (Tp) that is set in random access memory (RAM) similarly to the register (Tc).
), and in the next step (45S), the current encoder pulse generation time (C) is stored in the register c-rp.
Updated by copying.

Next step (/1.63), (/17B,), (5
In step 38), mode determination is performed.

If the speed 711 is in the constant mode (to 4o+) IC-〇), the speed measurement of steps (/l]S) to (/158) is performed and the process immediately returns to the main routine.

In the case of constant speed control mode (MODE, -1), the on time (T'on) of the motor (2) for a predetermined speed is calculated in step (483). Here, on time (1-on
) is the on-time (Tty) set corresponding to the predetermined speed.
p) It is obtained by adding a value obtained by multiplying the difference between the measured encoder pulse interval (Ti) and the reference encoder pulse interval (Ts) for a predetermined speed by a coefficient (K1).

Different values are used for (Ttyp), (T8), and (K') depending on the copying magnification during forward movement.

The ON time (Ton) determined in this way is added to the current time (1"f) and sent to the timer register (Tw) in step (498). As described above, the timer register (T' w) is a counter (T
f), and when they match, a timer interrupt is generated, so a timer interrupt will be generated exactly after the timer register (Tw) is set ('1.''o, n). During this time, motor (2) is on.

The main routine is interrupted and processed every time the timer value (Tw) is set.

That is, when a timer interrupt occurs, the motor drive signal (Dl is set to "0" in step (71B). After that, in the routine (INT-1!), the scan timer L is checked in step (5]8). , is negative, that is, when the timer is operating, it is incremented.

In the case of pulse counting mode (MODE=3), step (53S) determines "NOj" and step (588)
Then, only the position (pos) of the scanning system (1) is updated. Next, enter timing check mode (MO
DE=2) sampling processing will be explained. Does the standard deceleration data indicate the relationship between speed and distance?
This is done as follows.

First, the position of the scanning system (1) is measured as follows.

Pulses from the encoder (3) are generated in accordance with the amount of movement of the scanning system (1), so by counting these pulses, the distance traveled from a certain point can be determined. In this embodiment, the reference position for starting counting is the position where the brake switch (5) is turned on. Since the data to be stored is for the standard braking operation, by setting the reference position to the position corresponding to turning on the brake switch (5), both the processing and the number of data can be minimized. Also, the data stored is stored as an encoder (3), rather than as a speed:1: degree value, for ease of processing.
The pulse interval from 1 to 2 is treated as the number of pulses of the reference oscillator (8) counted by an internal counter (fc).

Step (61S) is a process corresponding to the above content, and since TEST=1 in the test scan, step (54S) is a process corresponding to the above content.
Step B) enters this step, and in step (588) the speed Ti of (r'os) is stored as the number of pulses in the area of the RAM corresponding to (p'os), which is incremented for each encoder pulse. The data in this RAM becomes standard deceleration data. The above is the phase 1 processing by Utest scanning.

Next, Phase 2 and Phase 3 are carried out during copying →
The processing will be explained. After the test scan is completed, the main routine waits for a scan request (SCAN signal) for copying, or at this time, the SCAN signal is sent from the master.
Once set, the actual scan begins in step (338). First, in step (34B), the TEST flag is reset, and the scanning conditions magnification MAG and copy paper size 5IZE are stored in internal temporary registers M and SL (step (35B)).

Next, this condition and the currently set condition MO.

SLC is compared in steps (368) (37B).

If the scanning conditions have changed, they are updated to new conditions in step (388), the LOCK flag is reset, and the braking timing (1) ELAY) is also set to 0''.After this, the reference scan is performed in the same way as the test scan. Pulse interval '1゛S
and scan timer L, and start scanning (step (=+5) (5s)). After this, step (22
Up to 8), the same processing as the test scan is performed.

Unlike the test scan, phase 2 during copying is in a waiting state until the LOCK flag is set in step (238). The LOCK flag is set in phase 2 when the predicted timing is determined. Once the prediction timing is determined, step (24S) (25S)
to start braking.

The predicted timing is determined by the external interrupt processing routine (i
NT-, I', ). In phase 2,
TEST=0. Since LOCK-0, step (5
98) is executed, and at this time, as described above, the current speed t is compared with the corresponding pulse interval T1 and the standard deceleration data RAM (POS) stored in the RAM.

When the detected speed exceeds the standard deceleration data, step (60B) sets the LOCK flag and uses the position (pos) at that time as the predicted timing (DJ'
l:LAY). This completes Phase 2 and immediately moves on to Phase 3. Step (26S) resets the FAST flag in preparation for phase 3. The FA, ST flag indicates whether the current prediction timing is early or late in the interrupt routine (INT-1).
This flag is used to notify the main routine from

When phase 2 is completed, the routine (INT-1!) processes steps from step (558) onwards. In phase 3, assuming that the current predicted timing is too early, it is checked in step (568) whether the speed has been decelerated to a predetermined speed Vhome. If Vhome decelerates, in step (57S) the current position (PO
S) to the temporary storage register ('FMl'RG),
l” A S T flag is set and (IN-JT-E
) mode to pulse count mode (MODE, = 3
). After that, the process returns to the home position and continues until interrupts are disabled in the main routine (step (2)).
78) (288)) Continue the pulse count mode, that is, skip from step (533) to step (588) to update the position (pos) value for each encoder pulse. On the other hand, if the predicted timing is different, the robot returns to the home position before the FAST flag is set. After interrupts are disabled, in phase 3, the predicted timing is corrected for the next return motion based on the current braking results. Corrections are made by F A S as described in 1iiJ.
If T = 1, that is, the braking timing is short, step (308) is performed to predict the difference between the VhOme decelerated position (TMr'RG) and the home position (pos) at the predicted timing (1). On the other hand, if the braking timing is slow, add it to step (3).
S), the speed when returning to the home position (Ti)
(detected in step (448))
) is added to (1) E i, A V ) to make corrections. This completes phase 3. On the next scan, only phase 3 is executed unless the mode is changed.

As described above, according to the present invention, phase 1 and phase 2 allow braking control with less wasted time to be performed depending on the machine in any mode, and furthermore, when the same mode is continued can perform the most efficient reciprocating motion of the machine.

Effects As detailed above, the present invention has a first step that determines the braking timing by comparing the stored reference speed and the detected speed;
Based on the measurement data from the previous braking, with a simple configuration and control means, braking can always be started at the appropriate timing under any scanning conditions, ensuring the scanning system returns to its normal position and shortening the return time. It is possible to achieve shortening.

[Brief explanation of drawings]

4 is a motor control circuit diagram, FIGS. 5 to 8 are diagrams schematically showing the movement of the scanning system, and FIGS. 9 to 11 are flowcharts of the control means. (1)... Running f system, (2)... Motor, (3)... Encoder, (4)... Port switch, (5)... Brake switch, (20)... -y/ /rocomputer. Applicant Minolta Camera Co., Ltd. Figure 1 Figure 2 Figure 5? , 3 Figure 4 Figure 6 Figure 7 Figure S Figure 7 a Figure 9 Figure q Figure C Figure q d Figure 1O a Figure 10@b □□-1 Figure 1I

Claims (1)

[Claims] 1. During forward movement of the scanning system, the DC motor is controlled at a constant speed, while during backward movement, it is first accelerated and driven, and when a predetermined braking timing is reached, braking is applied to stop the motor at the forward movement start position. A scanning device that reciprocates a scanning system by controlling the scanning system to reciprocate, comprising: a detection means for detecting a speed at each position of the scanning system; a storage means for storing a reference speed at each position of the scanning system during braking; a first braking means that compares the detected speed of the detecting means with a reference speed of the storage stage and starts braking when the detected speed reaches the reference speed field as the braking timing; a second braking means that measures the movement and corrects the braking timing during the next return motion according to the measured data; and a selection means that selects either the first or second braking means according to the scanning conditions. Scanning device with. 2. The scanning device according to claim 1, wherein the stage correction is performed at a distance to a field start position that is faster than the detected speed or a predetermined speed. 6. Claim 1 or 2, characterized in that the selection means selects the first braking means during the first backward movement and selects the second braking means during the subsequent backward movement. Scanning device as described. 4. Among the selection means, the first braking means is selected when the scanning conditions change, and the second braking means is selected when the scanning conditions do not change. Scanning device as described in Section. 5. The scanning device according to claim 4, wherein the scanning condition is a scanning length. 6. The scanning device according to claim 4, wherein the scanning condition is the scanning speed or paper size. 7. The scanning device according to claim 1, wherein the reference speed is a detected speed of a test reciprocating motion performed prior to copying when the power is turned on.