JPH05188486A - Method for controlling scanner optical system - Google Patents

Abstract

PURPOSE:To align the head end position of an image with the head end part of transfer paper by automatically correcting the timing of a signal generated when a scanner passes through the head position of a document. CONSTITUTION:A programmable interval timer 21 is connected to a microcomputer 20. This method is equipped with a stop position detecting means which detects the stop position as the home position of a scanner optical system, a movement distance detecting means which detects the movement distance of the scanner optical system, an image head end part signal generating means which generates the signal when the image head end part passes according to the output signal of the movement distance detecting means, and a memory stored with an error in the distance from the stop position of the scanner to the document head end part; when the scanner optical system is move forward, control is so performed that the scanner becomes stable at the specific speed from the stop position of the scanner to the position of the image head end part and the timing of the image head end part signal generated when the scanner passes through the image head end position is corrected through the scanning movement distance detecting means and stop position detecting means according to the memory contents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a scanner optical system, and more particularly, it relates to a problem caused by variations in the distance between the home position of the optical system scanner and the leading edge of the original reading due to the difference in assembly precision during manufacturing. The present invention relates to a resolved method for controlling an optical system scanner and means for facilitating maintenance when a failure occurs in the scanner.

[0002]

2. Description of the Related Art Generally, the optical system scanner portion of a conventional copying machine is shown in FIGS. 13 and 14, and a document is shown in FIG. A scanner optical system 3 is provided below a contact glass 2 on which an illumination light source 1 is placed, and the scanner optical system 3 integrally includes an illumination light source 4, a trough-shaped reflector 5 surrounding the illumination light source 4 and a first mirror 6. The second scanner unit 10 in which the first scanner unit 7 and the third and fourth mirrors 8 and 9 assembled together are integrally mounted at an angle of 90 degrees with each other, the imaging lens 11, the fourth mirror 12 and the like. It consists of The first scanner unit 7 and the second scanner unit 10 are driven forward in the right direction in the drawing at a speed ratio of 2: 1 to reflect the light emitted from the illumination light source 4 on the document and to reflect the reflected light to the first mirror. 6,
The structure is such that it is guided to the surface of the photoconductor 14 via the second mirror 8, the imaging lens 11, the fourth mirror 12, and the dustproof glass 13. A document abutting scale 15 is arranged at the left end of the contact glass 2 and is set so that the left end of the document 1 to be copied is brought into contact with the scale, and the illustration thereof is omitted. Start copying by covering with the document holding plate.

FIG. 13 is a schematic perspective view showing the outline of the transport mechanism of the optical scanner section. The first and second optical scanner sections 7 and 10 are forwarded by a scanner wire 17 for transmitting the rotation of a motor 16. It is designed to move.
Since the operation of this mechanism is well known in the art, a detailed description thereof will be omitted.
A sensor (referred to as an HP sensor) having a reflection type photointerplater configuration is arranged corresponding to the reference position of the second scanner section 7 when the second scanner section 7 is at the reference position HP (home position). A shield plate 19 arranged at a predetermined position of the scanner unit 7 blocks the HP sensor.

In such a configuration, the first and second scanner units 7 and 10 are driven to scan in the right direction of the drawing from the home position shown by the solid line in FIG. 13 to expose and scan the document surface. The two scanner positions shown by the broken lines in FIG. 13 represent the maximum movement positions of the reciprocating operation. The scanner unit, which has completed the exposure scanning of the document surface, returns to the home position and returns to the solid line position in the figure. This backward movement is generally driven faster than during forward movement, and
When approaching the home position, deceleration control is performed, and when the shielding plate 19 crosses the HP sensor 18, the motor 16 is rotated in the reverse direction to open the home position HP.
The baluned first scanner 7 is returned to its original position and stopped at a specified position.

Home position sensor HP sensor 1
8 is fixed, the position measuring means is driven from the state where the sensor is changed from the state where the shield plate is shielded to the state where the shield plate is not shielded, and if the motor is a stepping motor, one address is provided for each minimum rotation angle. If the motor has an encoder, one address is added for each encoder pulse and the position of the HP sensor from the home position at that time is accurately measured.

However, various assembling errors occur in the manufacturing process of the copying machine, and it is inevitable that the mounting position of the sensor is varied, the shielding plate mounting position of the scanner is displaced, or the document abutting scale mounting position error occurs. .. As a result, the distance from the HP sensor to the leading edge of the document differs for each device.

For this reason, conventionally, a fine adjustment mechanism for the mounting position of the HP sensor is provided, and the front end of the document of each device and the H
The distance to the P sensor was adjusted to be constant.

However, in such a conventional method, since the operation of measuring the distance is repeatedly performed while moving the sensor by a minute distance, a large amount of adjustment man-hours are required, which not only becomes a factor for reducing cost reduction. However, the following decisive problems occurred. That is, in a copying machine, the HP sensor and the original contact scale position are fixed, the position in the moving direction of the transfer paper is changed when the image formed on the photoconductor is transferred to the transfer paper, and the image front end is the front end of the transfer paper. There is a means for controlling the conveying speed of the transfer paper or a means for adjusting the transfer timing of the transfer paper so as to match with.

For example, there is one that delays the transfer of 1 mm transfer paper with respect to the image on the photoconductor as compared with the design target value. However, when the zooming function is operated by such adjusting means, the adjusting means may not be useful, and it is difficult to say that the adjusting means is a perfect adjusting means. That is, when the HP sensor and the image front end position are displaced by 2 mm, the object can be achieved by delaying the transfer paper by 2 mm in the case of equal-magnification copying, but, for example, in the case of 200% variable-magnification copying, Even if the transfer paper is corrected by 2 mm, the front end of the transfer paper and the front end of the image do not match. To be precise, the delay amount of the transfer paper should be changed according to the magnification change. FIG. 15 is a diagram for explaining the above-mentioned inconvenience. In the case of equal-magnification copying, the deviation of 2 mm can be corrected as shown in (a), but as shown in (b) at 200% magnification change. The image on the transfer paper cannot be corrected and is 2 m.
A correction residue of m occurs.

Further, since the scanner portion of such a copying machine is frequently driven and moves forward, mechanical abrasion is severe. Particularly, since the scanner portion moves forward while being in contact with the scanner rod, mechanical distortion occurs between the contact portions. If this occurs, smooth scanning cannot be performed and the copy image may be deformed. Therefore, conventionally, many devices are provided with means for monitoring the forward movement speed of the scanner portion and stopping the operation of the apparatus when a failure is detected in the operation. However, even if slight dust is attached to the contact portion between the scanner rod and the scanner, if an abnormality is detected in the operation of the scanner,
The equipment will be stopped and awaiting repair.In such a case, the dust causing the failure can be removed.However, if it is not clear what caused the failure, the presence of the garbage is noticed. Instead, the repair is often done by replacing the entire part. In this case, it takes a lot of time to order and exchange the replacement parts, which is uneconomical and causes a problem that the apparatus cannot be used for a long period of time.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the conventional image forming apparatus as described above.
(EN) Provided is a control method of a scanner optical system which does not require position adjustment between a P sensor and an image leading end portion and can automatically match the image leading end position with the transfer paper leading end portion even in arbitrary variable magnification copying. It is an object. Further, it is another object of the present invention to provide a scanner optical system control method which is provided with a convenient means for maintenance and maintenance of the scanner portion and can significantly shorten the time until failure recovery.

[0012]

In the present invention, in order to achieve the above object,
Reciprocating scanner optical system, scanner carrying motor for carrying the scanner optical system, stop position detecting means for detecting the stop position of the scanner optical system at the home position, and movement of the scanner optical system. Moving distance detecting means for detecting the distance, image edge signal generating means for generating a signal when passing through the image leading edge based on the output signal of the moving distance detecting means, the stop position of the scanner and the document leading edge. And a memory that stores an error in the distance to the scanner optical system, and controls so that the scanner stabilizes at a predetermined speed from the stop position of the scanner to the position of the image end when the scanner optical system moves forward, and the scanner moving distance The timing of the image leading edge signal generated when the scanner passes the image leading edge position is corrected from the detecting means, the stop position detecting means, and the memory contents. Characteristically, the minimum resolution of the correction amount data corresponds to the minimum step angle of the stepping motor when the motor for carrying the scanner corresponds to the stepping motor, and when the motor has an encoder, it corresponds to one pulse of the encoder. It is controlled to be equivalent.

Still another aspect of the invention is a scanner optical system capable of reciprocating operation, a scanner carrying motor for carrying the scanner optical system, a stop position detecting means for detecting a stop position of the scanner optical system, and the scanner. A moving distance detecting means for detecting a moving distance of the optical system, and the scanner is controlled so as to stabilize at a specified speed before moving to a predetermined position during forward movement, and the scanner passes through the leading position of the document to reach the maximum. The speed up to the moving position is monitored, and when the speed fluctuates beyond a predetermined speed range, at least one of the position of occurrence and the amount of fluctuation is stored in a non-volatile memory so that it can be read out as necessary. It is characterized by controlling.

The production management system of the present invention will be described below based on the illustrated embodiment. FIG. 1 is a diagram showing an embodiment of a control circuit of a scanner optical system of a copying machine according to the present invention. A microcomputer 20 which is the center of the control circuit.
A programmable interval timer 21 using, for example, a µPD8253C is connected to the second scanner optical system 10
DC motor 16 for driving the transistors TR ₁ to Tr
It is connected to the microcomputer 20 and the programmable 21 via a motor drive circuit 22 composed of _four .
The motor drive circuit 22 includes transistors TR ₁ and TR ₃
Is on and the transistors TR ₂ and TR ₄ are off, the DC motor 16 rotates clockwise (CW),
If the on / off of the above transistor is reversed, the motor 16
Rotates counterclockwise (CCW).

When the motor rotates clockwise, the second scanner optical system 10 moves forward and reversely rotates backward. Further, a rotary encoder E is connected to the motor as a pulse generating means, and the rotary encoder E is connected to the rotary encoder E.
Generates two pulse signals ENCA and ENCB having different phases according to the rotation amount and rotation direction of the DC motor. EN
CA is the A phase encoder pulse, while ENCB is the B phase encoder pulse.

The A-phase encoder pulse ENCA is input to the counter input terminal CI of the microcomputer 20 via the buffer circuit 23, whereby the microcomputer 20 counts the A-phase encoder pulse interval in the internal counter. Measure at. A pulse signal from the clock oscillator 24 is supplied to this counter. Also, the input signal to this counter input terminal CI is an interrupt input, and the measurement data (TIMER / EVENT COUN
TER CAPURE REGISUTER -ECPT value) is read, and based on this data, the DC motor rotation speed (scanner speed) is calculated, the error from the target rotation speed (target speed) is calculated, and motor control by proportional / integral control calculation ( Calculation and output of ON time in pulse width modulation PWM control, that is, data load to the programmable interval timer 21 is executed.

On the other hand, the B-phase encoder pulse ENCB
Is input to the input terminal PC7 of the microcomputer 20 through the buffer circuits 23 and 25 and the flip-flop circuit 26 together with the A-phase encoder pulse ENCA.
The rotation direction of the DC motor is determined according to the phase difference between the two signals. In addition, the programmable interval timer 2
An oscillator 27 is connected to 1 as a clock signal supply source.

In this way, the rotation amount of the DC motor 16 is controlled by the PWM control. That is, the PWM cycle is loaded into the counter 0 of the timer 21, and the square wave of the PWM cycle is output from the output OUT0 of the counter 0. This signal is the gate input of the counter 1. The ON time data of the PWM signal is loaded into this counter and P
A one-shot output synchronized with the WM cycle is output from OUT1 and is transmitted through the gate circuits 28 and 29 to the transistor T.
ON / OFF control of R ₃ or TR ₄ .

FIG. 2 is a diagram showing an example of the waveform of the above-mentioned PWM control signal, and shows that the sum of the ON time tON and the OFF time tOFF is constant as one cycle. Here, the counter 0 is set to the square wave generator and the generator of the mode 3, and the counter 1 is set to the programmable one shot of the mode 1. Since the PWM cycle t (tON + tOFF) is constant, it is sufficient to set the count number of counter = 0 once unless it is changed, and the count number of counter 0 is loaded when the ON time of PWM is changed.

FIG. 3 is a waveform diagram for explaining the contents of the mode 3 of the programmable interval timer 21.
The timing chart of the square wave rate generator is shown, and in this case, it operates as an n division counter of the input clock. If the count is an even number,
The duty ratio is 1/2 and the duty ratio is (n-1) / 2n when the count number is odd. For example, when the counter number n = 5, the duty ratio in this case is 2/5 (active low).

Then, this mode is set in the control word.
When the mode is selected, OUT0 = 1, GETE1 = 1, the count number is loaded, and the count is started. When the number of counts is even, the first half of the count 1
/ 2 is OUT0 = 1, and the latter half is OUT0 = 0. or,
When the number of counts is odd, the first half of the count (n + 1)
/ 2 is OUT0 = 1, the latter half (n-1) / 2 is OUT0
= 0. When GETE1 = 0, OUT0 = 1 and the counting stops in synchronization with the rising edge. After that, when GETE1 = 1, the counting is restarted from the initial value, and if the counting number is loaded during counting, a new counting is started from the next cycle. When the count number is even, the counter is decremented by two, and when it is odd, when OUT0 = 1, it is decremented by the first one clock and from the second clock by two.

FIG. 4 shows a timing chart of mode 1, that is, programmable one-shot, which is a one-shot pulse (active low) of a specified length.
Is output. When this mode 1 is selected in the control word, OUT0 = 1 and the count is started after the count number is loaded and triggered by the rising edge of GETE1. OUT0 becomes 0 during counting, and OUT0 becomes 1 again when the counting ends. That is, the pulse width becomes an active low one-shot pulse output corresponding to the count number. If a trigger is applied during counting (when GETE1 is changed from 0 to 1), counting is restarted from the initial value. Note that loading the count number during counting does not affect the count being executed, but triggering during counting starts counting with a new count number.

Next, the operation of the scanner from the start of the scanner to the passage of the leading edge of the original will be described. As described above, when the HP sensor is passed during the forward movement of the scanner, the scanner is subjected to a brake due to the reverse rotation of the motor, and the brake is applied until the encoder output of the motor indicates the reverse rotation. As a result, the scanner stops and the HP sensor is blocked by the shield plate of the scanner, and this sensor outputs a signal indicating that the scanner is in the home position.

In this state, the next scan is started, and the optical system control that receives the scanner start start command from the outside supplies electric power to the drive motor to perform the scanner forward movement. The scanner gradually increases the speed from the zero speed state, and in this acceleration state, the HP sensor changes from the shielded state to the non-shielded state.

At this time, the address of the scanner is set to 0, and a pulse signal is output from the encoder at a predetermined rotation angle of the motor, that is, every time the scanner moves a predetermined distance, and the pulse signal resets to 0 in advance. The scanner address is incremented by 1.

FIG. 5 is an explanatory diagram summarizing the reciprocating operation of the scanner as described above. The speed of the scanner and H
It is a figure which shows a P sensor output waveform. The scanner is moved forward by the start of scanning, and after reaching a predetermined speed after a slight speed fluctuation, reaches the leading edge of the document. Further, when the scanner reaches the maximum movement position, it moves back in the opposite direction, and the speed at this time becomes faster than that in the forward movement.

An automatic control circuit is generally used for controlling the speed of the scanner. The concept of this automatic control is shown in FIG.
It shows in (b). That is, as shown in FIG. 9A, the speed of the controlled object itself is detected and compared with the specified speed, and the control is performed so that the difference between the two becomes zero. Depending on the magnitude of the loop gain of, the state of speed fluctuations differs. FIG. 6B is a diagram showing the relationship between the gain and the state of speed stability.

FIG. 7 shows the encoder output ENCA and ENCB signal output waveforms, the C1 terminal input signal waveform of the microcomputer, the P7 terminal input waveform, the HP sensor output waveform and the motor as the scanner moves forward. 3 illustrates a signal waveform indicating the rotation direction of the. Further, FIG. 8 is a flow chart showing the basic control procedure of the scanner, which is shown in association with the numbers attached to the waveform chart of FIG.

Now, assuming that the distance from the home position of the scanner to the LE (member for defining the leading end of the document such as the document abutting scale) is 30 mm by design,
As described above, this distance causes variations in assembly,
In the present invention, this variation is absorbed as follows.

That is, after the device is assembled, how much the above distance deviation is accurately measured, and this value and the designed value of 30 mm are stored in the memory, so that the mounting dimension of each device is set to the designed value of 30 mm. Is used as the median value to calculate the true document leading edge position. The calculated value is used to correct the value of the scanner address data which is added in correspondence with the encoder pulse of the scanner described above, and the original leading edge passing signal, that is, the LE signal is generated. Here, the stored value is referred to as an LE adjustment value.

FIG. 9 and FIG. 10 are flow charts for explaining the control procedure in the embodiment of the present invention. In this example, the scanner moves by 0.2 mm for each encoder pulse of the scanner. The case where the design value of the distance between the HP sensor and the LE is 30 mm is illustrated.

In FIG. 9 showing the scanner control flowchart, when the power is turned on, a scanner start command is generated and the motor rotates at the PWM value for starting. After that, according to the PI control by the proportional gain and integral gain set at the time of starting the scanner, the PWM value at that time is updated according to the scanner speed, that is, the interval time of the encoder pulse so that the speed approaches the specified speed. Control.

That is, the procedure will be described with reference to FIG. 9. First, the power is turned on (ST1), the scanner status is 0 in the initial operation of the scanner, that is, the scanner start command is awaited (ST2), and the scanner start signal is received. Then, the scanner status is set to 1 (ST3) (ST4), and in this state, the PWM value, the proportional gain, and the integral gain I at the time of starting the motor are set and are connected to the interrupt terminal of the microcomputer. By allowing the encoder input, the encoder pulse input can be counted (ST5). When such a series of processing is completed, the scanner status is set to 1
From 2 to 2 (ST6), the acceleration / constant speed control of the scanner by PI control is executed (ST7).

FIG. 10 is a diagram showing a control flow in the state where the scanner status is 2. First, the shielding state of the HP sensor is monitored, and 0 is set to the scanner address in the shielding state (ST11). When the HP sensor of the scanner becomes unshielded, the scanner status is set to 3 (S
T12). When the scanner status becomes 3, the LE output timing is monitored, and the scanner address LE indicates the number of encoder pulses corresponding to the target value 30 mm of the design value, that is, 150 counts in this example, and the deviation amount from the target value (target value). When the scanner address as a result of addition and subtraction with the adjustment value becomes larger than the result value of the addition and subtraction, the document leading edge passing signal, that is, the LE signal is generated and the scanner status is set to 4 (ST13 to 16).

If the LE shift amount at this time is managed in 0.2 mm steps, the LE position can be determined with one minimum resolution of the scanner, and the leading edge of the document can be accurately detected.

Next, the second aspect of the present invention will be described. Before that, the cause of the speed fluctuation of the scanner will be described. FIG. 11 is a diagram showing the speed fluctuation of the scanner. Relationship between dynamic process and velocity and Fig. 6
Reference is made to (a) and (b), which are explanatory views of the feedback system for automatic control.

Although FIG. 5 shows the operation of the scanner for one cycle, if there is a slight dust on the scanner rod or the like, the scanner speed partially changes and the above-mentioned problems occur. Particularly, since the scanner rod is coated with lubricating oil to make it slippery, dust and the like easily adhere to it. As a result, as shown in FIG. 11, fluctuations in speed occur in the portion that should originally move at a constant speed. There are many possible causes of such speed fluctuations other than the above. For example, there are variations in the coefficient of friction among machines during machine assembly, uneven wear due to aging of the scanner, partial thermal expansion of mechanical parts due to heat of the exposure lamp, solidification of lubricating oil, and the like.

The broken line in FIG. 11 is the target value for normal operation, but the dashed-dotted line shows the operation of the scanner when there is a portion where the load is large, and the solid line curve portion, conversely, the load is partially reduced. In any case, the operation deviates from the specified speed in any case. Therefore, in the present invention, by adding the following means, it is possible to quickly find the cause and enable prompt repair.

[0039] That is, the control of the scanner as described above diene - PWM value applied to the scanner motor every sampling of the input Da, i.e. the operation amount performed by PI control, the manipulated variable Y _N This expression Given in. Y _N = K _P · en + (1 / K _i ) · Σen (1) where en is the current speed deviation from the target value, and K
_P is generally called a proportional gain, and K _i is a circuit parameter in automatic control technology called an integral gain.

The scanner control method will be further described with reference to this equation and FIG. There is a limit sensitivity method as a method used when setting the above-mentioned proportional constant, and this is to set the gain to be considered to be optimum by monitoring the behavior of the controlled object by gradually increasing the gain. As shown in FIG. 6B, when the proportional gain is small, the vibration proceeds in a direction of converging. On the contrary, when the gain is large, the vibration continues, and when the gain is further increased, the vibration grows and diverges, which makes control impossible. Become. In the PID control, the vibration is determined within a range smaller than the sustained gain. Note that other gains such as an integral gain and a differential gain are determined according to the continuous vibration frequency. Such vibration occurs not only when the gain is changed, but also when the load of the controlled object changes.

According to the present invention, when the speed of the scanner changes due to the above-mentioned causes, the generation of the fluctuation signal is detected from the loop of the control system, and the fluctuation signal is stored in the memory in correspondence with the position of the scanner. To do. According to this method, when a failure occurs in the scanner system, the maintenance worker can quickly and accurately know at which position of the scanner the speed change has occurred by reading the stored contents. It is possible to find causes that are difficult to find, such as fine dust and solidification of lubricating oil, and it is possible to save extra parts and labor.

As an actual application example, if the reference measure of the scanner is V and the allowable speed range is 2%, V ± 0.
When the range is 02V, the scanner position is stored in memory.

FIG. 12 is a flow chart showing one embodiment of such control. The above operation is carried out by the control of the encoder interrupt routine of FIG. 9 in the explanation of the first embodiment of the present invention described above. An example is shown.

That is, in FIG. 12, the scanner moves forward,
By adding / subtracting the scanner address according to the backward movement, the position of the scanner is specified and stored as necessary. For example, the address of the home position of the scanner is 4
00, the address is added for each pulse of the encoder in the forward movement as the scanner moves, and conversely is subtracted in the backward movement.

The scanner speed is controlled so as to be constant between the home position of the scanner and the LE, and for example, from the home position to the LE, there are 50 encoder pulses, and therefore the LE. The scanner address of the position is 450. Further, whether the scanner is moving forward or backward can be known by detecting the rotation direction of the scanner motor.

With reference to FIG. 12, assuming that the address of the leading edge of the document is 450, the encoder interruption is performed after the counter, which measures the distance, exceeds 450 and reaches the maximum movement position of the scanner. Interval EC
Always monitor PT. The scanner speed is calculated by the value of this ECPT and comparison with V ± 0.02V is executed. If the value exceeds the value, all the scanner addresses at that time are stored. The position information can be obtained by integrating the number of encoder interruptions from the home position of the scanner. At this time, if the same position is stored a plurality of times, the memory is wasted. Therefore, the position information in which an abnormality has occurred may be compared with the already stored contents, and newly stored only when the contents are different. Also, the maximum value of speed deviation should be stored at all times.

[0047]

As described above, according to the present invention, the adjustment between the home position and the leading end position of the original is automatically corrected in the control of the scanner optical system of the copying machine. Since it is not necessary to adjust the deviation due to the mounting error of each component for each device, it is possible to significantly reduce the adjustment man-hour. Further, according to the present invention, even a copying machine which performs the above-mentioned correction by controlling the transfer speed of the transfer paper and has a variable magnification function can automatically correct the copy without any trouble. Further, according to the second aspect of the present invention, when an operation failure of the scanner optical system is possible, it is possible to quickly know the failure location, so that it is possible to remarkably shorten the repair work time.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit example of a control unit of a scanner optical system in a copying machine according to the present invention.

FIG. 2 is a diagram showing a waveform of a PWM control signal.

FIG. 3 is a signal waveform diagram for explaining the operation of the programmable interval timer.

FIG. 4 is a signal waveform diagram for explaining the operation of mode 1.

FIG. 5 is a diagram showing the relationship between the reciprocating operation of the scanner optical system and the speed and HP sensor output.

6A and 6B are a block diagram and an operation waveform diagram for explaining the operation of the automatic control system for controlling the speed of the scanner optical system and the principle of coefficient determination.

FIG. 7 is a diagram showing input / output signal waveforms of respective units corresponding to a scanner operation.

FIG. 8 is a basic flowchart of scanner control.

FIG. 9 is a flow chart of scanner position correction control showing an embodiment of the present invention.

FIG. 10 is a flow chart at the time of encoder interrupt control in one implementation order of the present invention.

FIG. 11 is a diagram illustrating a cause of speed fluctuation of the scanner.

FIG. 12 is a flowchart showing a control example of the second invention.

FIG. 13 is a side schematic configuration diagram showing an embodiment of a scanner portion of a copying machine to which the present invention is applied.

FIG. 14 is a perspective external view showing a specific structure of a movable part of the scanner optical system.

15 (a) and 15 (b) are plan views for explaining a problem at the time of operating the variable magnification function in the conventional copying machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 original, 2 contact glass, 3 scanner optical system, 4 illumination light source, 5 reflector, 6, 8, 9, 12 mirror, 7 first scanner, 10 second scanner, 11
Imaging lens, 13 dust-proof glass, 14 photoconductor, 15
Original abutting scale, 16 motor, 17 scanner wire, 18 HP sensor, 19 shielding plate, 20 micro computer, 21 programmable interval timer, 22 motor drive circuit, 23, 25 buffer circuit, 24 clock oscillator, 26 flip-flop , 27 oscillators, 28, 29 gate circuits.

Claims (3)

[Claims] 1. A reciprocating scanner optical system, a scanner carrying motor for carrying the scanner optical system, a stop position detecting means for detecting a stop position of the scanner optical system at a home position, and Moving distance detecting means for detecting the moving distance of the scanner optical system, image end signal generating means for generating a signal when passing through the image leading end based on the output signal of the moving distance detecting means, and stopping the scanner as described above. A memory that stores the error between the position and the distance to the leading edge of the document is provided, and the scanner is controlled to stabilize at a predetermined speed from the stop position of the scanner to the position of the image edge when the scanner optical system moves forward. From the scanner moving distance detecting means, the stop position detecting means, and the memory contents, the timing of the image leading edge signal generated when the scanner passes the image leading edge position is determined. A method for controlling a scanner optical system characterized by correction. 2. The method according to claim 1, wherein the minimum resolution of the correction amount data corresponds to the minimum step angle of the stepping motor of the scanner carrying motor, and the motor has an encoder. Is a control method of a scanner optical system, which is controlled so as to correspond to one pulse of the encoder. 3. A reciprocating scanner optical system, a scanner carrying motor for carrying the scanner optical system, stop position detecting means for detecting a stop position of the scanner optical system, and movement of the scanner optical system. A moving distance detecting means for detecting a distance, and the scanner is controlled so as to stabilize at a specified speed before moving to a predetermined position during forward movement, and the scanner passes the document leading position to reach the maximum moving position. The speed is monitored during a period of time, and if the speed fluctuates beyond a predetermined speed range, at least one of the position of occurrence and the amount of fluctuation is stored in a non-volatile memory, and control is performed so that it can be read out as necessary. A method of controlling the scanner optical system, which is a feature.