JPH0711673B2 - Initial stop position control method for copier optical system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for controlling an initial stop position of an optical system in an optical system movable copying machine.

<Prior Art and Its Deficiencies> Generally, in an optical system movable copying machine, a document is exposed at a constant speed when the optical system is fed, and is returned to a home position at a high speed when returning. Further, a home position sensor is arranged at the home position, and when this sensor detects that the home position of the optical system has been returned, the home position sensor is stopped at a predetermined position. However, the initial position where the optical system is stopped is not always constant at the time of initializing when the power is turned on due to the occurrence of jams during transportation of the copying machine or during the copying process. It may be stopped at the stop position or on the opposite side. For example, when the optical system is stopped between the home position sensor position and the regular stop position and the scanning of the optical system related to the next copying process is started from this position, the preliminary scanning distance becomes insufficient. Feed speed is insufficient at the leading edge of the document. Also, if the optical system is stopped on the opposite side of the home position sensor position from the normal stop position side and relatively close to the home position sensor position, simply move the optical system to the normal stop position direction. In the process of only moving the optical system to the home position sensor position and stopping it based on the timing when the optical system passes the home position sensor position, the moving speed of the optical system when the optical system passes the home position sensor position becomes insufficient, Eventually, it stops between the home position sensor position and the regular stop position, and if scanning of the optical system related to the next copying process is started from this position,
The preliminary scanning distance is insufficient and the feed speed is insufficient at the document leading edge position.

Thus, depending on the stop position of the optical system, it may not be possible to guarantee the feed speed of the optical system at the document leading end position in the next copying process. In such a case,
There is a problem that an accurate copy image cannot be obtained.

<Objects of the Invention> The object of the present invention is to solve the above-mentioned drawbacks, to accurately set the stop position of the optical system at the time of initializing the optical system such as when the power is turned on, and even when the preliminary scanning distance is short, the leading edge of the image area is short. It is an object of the present invention to provide a method for controlling an initial stop position of an optical system of a copying machine, which can achieve a stable feed speed.

<Structure of the Invention> The present invention compares the initial position with the home position sensor position at the time of initializing the optical system such as when the power is turned on, and the initial position is on the stop position side with respect to the home position sensor position. When in the initial stop mode, feed a predetermined distance, then control the speed so that the home position sensor position has a constant speed, and then return.
At the home position sensor position, the motor is braked from the constant speed to move to the stop position, and in the second initial stop mode in which the initial position is on the opposite side of the home position sensor position from the stop position, a predetermined value is set. When the home position sensor position reaches the constant speed at the time of return, the motor is braked from the constant speed at the home position sensor position to move to the stop position. If the home position sensor position does not reach the certain speed, the motor is braked at the home position sensor position to pass the position between the home position sensor position and the stop position and then the first initial stop. It is characterized by shifting to a mode.

<Embodiment> FIG. 2 is a schematic structural diagram of a copying machine in which an initial stop position control method according to the present invention is implemented. A photoconductor drum 2 is arranged substantially in the center of the main body 1 of the copying machine.
A developing unit, a transfer unit, a static eliminator, etc. are arranged. An optical system 3 including a zoom lens 30 that horizontally moves according to a set magnification is arranged above the photoconductor drum 2, and a paper feed tray including a paper feed tray and a cassette mounting unit is provided on the right side of the photoconductor drum 2. On the left side, there are arranged a conveying section 5 for conveying the sheet after transfer and a fixing section 6 composed of two rollers.
A document cover 7 is rotatably attached to the upper part of the copying machine main body 1, and by setting the document under this, an image corresponding to the document is formed on the photosensitive drum 2 by the feed scanning of the optical system 3. The drive timing of the paper feed roller 40 that conveys the paper from the paper feed unit 4 toward the photosensitive drum 2 is controlled by the paper start clutch PSC in order to align the front end of the paper with the front end of the image on the drum. The control of the on / off timing of the paper start clutch PSC is performed by the slave CPU for optical system movement control described later.

FIG. 3 is a perspective view of an essential part of the optical system 3 of the copying machine. In the optical system 3, the optical system scanning unit 31 that scans a document is a light source 31.
Mirror base that integrates a and two mirrors 31b and 31c
Mirror 31 that reflects the reflected light from MB1 and the original to mirror 31b
It consists of a mirror base MB2 that supports d. These mirror bases MB1 and MB2 are horizontally slidably supported by two rails 32 and 33. One side portion 34 of the mirror base MB1 is fixed to the wire 35, and the mirror bases MB1 and MB2 are both moved to A in accordance with the movement of the wire 35 in the A or B direction.
It moves in the direction (feed direction) and B direction (return direction). The wire 35 is wound around the pulleys 36 and 37 and the rotating shaft of the DC motor 38, and the mirror bases MB1 and MB2 reciprocate according to the forward and reverse rotations of the motor 38.

The side 34 for fixing the wire of the mirror base MB1 is a vertical piece 3
A home position sensor HPS which has the vertical axis 34a and detects the vertical piece 34a is arranged in the stop area of the mirror base MB1. It is a range from when the rear end C of the vertical piece 34a in the stop area of the mirror base MB1 is moved to the B direction (return direction) by about several tens of millimeters after the optical path of the home position sensor HPS is cut off. The position where the rear end portion C of the vertical piece 34a has moved by about 10 mm after passing the set position of the home position sensor HPS becomes the mirror base MB1, that is, the stop position of the optical system.

In this embodiment, the control unit of the copying machine has a master CPU and a slave CPU.
It consists of and. The slave CPU receives signals from the home position sensor HPS, a rotary encoder RE (not shown) connected to the motor 38, and other sensors to control the rotation speed of the motor 38 and the paper start clutch PSC. FIG. 4 is a schematic block diagram of the control unit. The CPU is a master CPU (MCPU) 50 and a slave CPU (SCP
U) 51 and the MCPU50 sends a mirror start command and a mirror initial command to the SCPU51,
The SCPU51 sends status and the like to the MCPU50. The MCPU50 receives signals from the input keys, various sensors, etc., and sends commands to the SCPU51 according to a program previously defined in the ROM52, receives status from the SCPU51, and controls various solenoids, main motors, and the like. SCPU51 is MC
In response to a command sent from the PU 50, a signal from the sensor HPS, the rotary encoder RE, etc. is received according to a program pre-specified in the ROM 53, and the on / off timing of the paper start clutch PSC and the rotation speed of the motor 38 are controlled. Also, after performing a predetermined operation, the status or the like is transmitted to the MCPU 50.

FIG. 5 is a diagram for explaining the optical system return speed control method in this embodiment.

The figure shows the mirror base speed and the rotation speed of the motor 38 until the mirror base MB1 feeds from the stop position and returns to the stop position again after receiving the mirror start command from the MCPU 50.

The mirror base MB1 is located at the initial stop position P. As will be described later, when the power is turned on, the optical system is accurately stopped and controlled at the stop position P by the mirror initial command sent from the MCPU 50. When the motor 38 is driven in this state, the motor 38 is accelerated in the feed direction and enters the image area beyond the stop area up to the home position sensor HPS position Q point. The degree of acceleration is set to be large in proportion to the set magnification. The mirror base speed is stabilized at the stage where the leading end position R of the image area is reached, and the speed is controlled so as to be constant until the end point S of the image area is reached. Stabilization of the mirror base speed in this image area is performed by the SCPU 51 reading a pulse train obtained from the rotary encoder RE and outputting a motor drive signal so that the pulse period becomes constant. In the figure, R10 to R12 indicate the motor rotation speed corresponding to the set magnification, and indicate that the mirror base speed in the image area differs depending on the set magnification.

When the SCPU51 detects that the number of pulses from the rotary encoder RE has detected that the mirror base MB1 has moved in the feed direction and has exceeded the end point S of the image area,
The SCPU 51 brakes the motor 38 in the reverse direction. Then mirror base
The speed of MB1 in the feed direction rapidly decreases, and the cycle of the pulse train output from the rotary encoder RE also increases accordingly. When the cycle exceeds a certain size, the SCPU 51 detects that the mirror base MB1 stops moving in the feed direction and starts moving in the return direction. Point U in the figure is a position where the cycle of the output pulse of the rotary encoder RE is one step before the maximum. SCPU51
When this U point is detected, the return speed is the feed speed
The motor drive signal is output so that the maximum speed R1, which is considerably faster than R10 to R12, is achieved. The speed of the mirror base MB1 in the return direction is stabilized at the maximum speed R1 after a certain time, and is controlled until the mirror base MB1 moves a certain distance L at the speed R1. When the vehicle is controlled to the maximum speed R1 and moved by a certain distance L from the point U, the speed is then decelerated to the speed R2. The speed R2 is a speed at which the mirror base MB1 can be stably stopped at the stop position P when the sensor HPS position is changed to the motor braking state.
The size of the speed R2 is set to an appropriate size in consideration of the stop region E, the maximum speed R1, and other various factors that affect the inertia. As soon as the sensor HPS position Q is reached at speed R2, the motor 38 is reversely braked. Then, when the motor rotation speed reaches the value of R3 described later, the motor is turned off and stopped at the stop position P.

Speed R3 at point X when reverse rotation braking is switched to motor off
Is a size that allows the vehicle to accurately stop at the stop position P when the reverse rotation braking is switched off. Its speed R3
The magnitude of does not have to be set strictly in consideration of various factors that influence inertia like the speed R2, and is the low speed of the stop straight line. Mirror base MB1 speed at this time is N
Let be L. In this embodiment, reverse braking is performed at the position Q, and then the motor is turned off at the point X to stop at the stop position P. However, power generation braking is performed at the point Q and the stop position P is maintained. Alternatively, the reverse braking may be performed at the point Q, and the dynamic braking may be performed at the point X. In the former case, the stop area E is somewhat longer than in the above embodiment, but the stop position P can be accurately set by appropriately setting the decelerated R2.

With the above control, when the mirror base MB1 returns, it moves at the maximum speed R1 in the first stage, then the sensor HP
When the vehicle shifts to the braking state at the S position, it moves to the stop position P at a decelerated speed R2 that can be stopped stably, so that the return time of the mirror base MB1 is shortened and the stop accurately occurs at the stop position P. Moreover, since switching from speed R1 to R2 and switching from R2 to the braking state are performed without using a clutch or the like, there is little shock and a smooth return operation can be realized. Also the maximum speed
Since the control is performed so as to enter the stop area after decelerating from R1 to R2, the stop area E may be short.

FIG. 6 is a diagram illustrating a braking method in the stop area E.

When the SCPU51 detects the Q point by the HPS signal, the operation mode changes from the clockwise rotation mode (cw) to the counterclockwise rotation mode (cc
w.). Then, the motor 38 is a mirror base MB1,
The inertial force of MB2 is absorbed and its rotation speed begins to drop rapidly. At the same time, the output of the rotary encoder RE has a pulse cycle that increases from Tn _{-1 to} Tn ... As shown in the figure, and when the rotation speed reaches R3 (NL) immediately before the stop, the pulse cycle of the RE output becomes T. This cycle T is detected by comparing it with a threshold value Tth stored in advance in the ROM area of the SCPU 51. In this way, by monitoring the output of the rotary encoder RE with the threshold value Tth, it is possible to detect the state immediately before the motor 38 that has shifted to the reverse rotation control mode is stopped.

Next, regarding the mirror-based initial stop position control method,
It will be described with reference to the drawings. This figure is a sequence diagram at the mirror (base) initial.

In the figure (A), the initial position Y is the home position sensor HPS.
It is a sequence diagram in the case of being sufficiently distant from the position on the opposite side of the stop position P (second initial stop mode). In this case, the speed is controlled so that the speed becomes constant R2 from the initial position Y, and the speed becomes R2 at the point C,
When the sensor HPS position is reached with R2, deceleration control is performed. When the point X is reached, that is, when the motor speed reaches R3 (NL), the mode is changed to the stop mode, the motor is turned off, and the stop position P is reached.
Stop at a point. As described with reference to FIG. 5, the speed R2 is a speed at which the motor can be accurately stopped at the stop position P when the sensor HPS position Q shifts to the motor braking state when the mirror base returns. Therefore, the same figure (A)
The movement of the mirror base in the stop area E from the sensor HPS position Q point to the stop position P point at the time of the mirror initial shown in FIG. 5 is exactly the same as the movement of the mirror base in the stop area E shown in FIG. As a result, the mirror base can be accurately stopped at the point P even if the initial position of the mirror base is located on the right side of the point Q as shown in FIG.

FIG. 6B shows a sequence diagram when the initial position Y is on the left side of the sensor HPS position Q, that is, on the stop position side (first initial stop mode). In this case Mirror Base MB
In No. 1, the speed is first controlled to a constant speed V on the feed side, and when it is moved by an appropriate length Li, reverse braking is performed, and the return operation is directly performed. When the return speed reaches R2 and reaches the sensor HPS position Q point, reverse braking is performed as in the above to stop at the stop position P point. Also in this case, the mirror base is controlled to the speed R2 at the sensor HPS position Q point by the return operation, so that the mirror base accurately stops at the stop position P point.

In the same figure (C), the initial position Y is located slightly to the right of the sensor HPS position Q point (second initial stop mode).
FIG. In this case, even if the vehicle accelerates in the return direction so as to reach the speed R2 as shown in FIG. Therefore, reverse braking is performed at point C, and when the point reaches point D, the same sequence operation as in FIG. That is, after the point D is reached, the speed is controlled in the feed direction so that the speed is constant V, the distance Li is moved, the reverse braking is performed, and the direction is returned to Q.
The speed is controlled so that the speed becomes R2 when the point is reached.
As a result, even if the initial position is slightly displaced to the right of point Q, it is possible to accurately stop at stop position P.

The velocity V and the distance Li are experimentally determined so that the velocity becomes R2 when the mirror base moves in the return direction and reaches the point Q.

Next, the initial stop position control operation by the SCPU 51 will be described with reference to FIG.

First, step n1 (hereinafter step ni is simply referred to as ni)
At, it is determined whether the initial position Y of the mirror base MB1 is on the stop position side or the opposite side to the sensor HPS position Q point. If the initial position Y is not on the stop position side, n1 →
If it is on the stop position side, proceed to n1 → n2. In the case of the sequence shown in FIGS. 1A and 1C (second initial stop mode), the process proceeds from n1 to n9. In the case of the sequence shown in FIG. 1 (B) (first initial stop mode), n1 →
Continue with n2.

At n2, the rotation direction of the motor 38 is set to the feed side of the mirror base, and the feed speed is set to V. Next, at n3, the motor 38 is turned on, and at n4 and n5, it is detected that the home position sensor HPS is switched from on to off. Further, when the distance Li is moved by n6, the rotation direction is switched to the return side and the return speed is set to R2 (n7). Then, the motor is turned on at n8, and it is detected that the sensor HPS is switched from off to on while controlling the return speed to R2 at n11 and n12. When the sensor HPS switches from off to on, it is determined in n13 whether the speed at that time is R2. If it reaches R2, proceed to n14, brake the motor in reverse, and detect at n15 that the rotation speed is below R3 (NL). When the rotation speed falls below R3 (NL), the motor is turned off at n16 and the process ends.

In the case of the second initial stop mode in which the initial position Y is located to the right of the sensor HPS position Q, the process proceeds from n1 to n9, where the rotation direction is set to the return side and the return speed is set to R2. To do. Then, the motor is turned on at n10, the speed is controlled to become R2 at n11, and it is detected at n12 that the sensor HPS is switched from off to on. Subsequently, in n13, it is determined whether or not the speed at which the sensor HPS output is switched from off to on has reached R2. If so, the sequence is as shown in FIG. 1 (A), and therefore the sequence proceeds from n13 to n14, and the same braking mode as described above is executed in n14 to n16. If the speed has not reached R2, proceed to n13 → n17. In this case n17, n18
The reverse rotation braking of the motor is detected at, and it is detected that the rotation speed becomes R3 (NL) or less, and when the rotation speed becomes NL or less, the flow returns to n2, and the same operation as the sequence shown in FIG. To execute.

By the above operation, it is possible to accurately stop at the stop position P regardless of whether the initial position is on the stop position side or on the opposite side to the home position sensor position. Therefore, by executing this initial stop position control after the power is turned on, the stop position of the mirror base can always be set accurately before the copy start.
In this embodiment, even when the SCPU51 receives the mirror start command, the mirror base is moved to the home position sensor position at the speed R2 when the mirror base returns. Therefore, the stop position of the mirror base is kept constant at the time of initial operation. There are advantages. Further, although the optical system movable copying machine has been illustrated in the above description, the present invention can be easily applied to the table moving type copying machine so as to perform the relative operation.

<Advantages of the Invention> As described above, according to the present invention, since the stop position can be accurately set at the time of initializing the optical system, it is not necessary to set the preliminary scanning distance to a marginal length, There is an advantage that can be set to the length of. Therefore, the speed in the image area at the time of feeding can be controlled to a stable speed from the leading end to the trailing end, and the entire preparatory scanning distance can be minimized so that the entire copying machine can be downsized.

[Brief description of drawings]

FIGS. 1 (A) to 1 (C) are sequence diagrams at the mirror initial stage of an example of the initial stop position control method according to the present invention. Further, FIG. 2 is a schematic configuration diagram of a copying machine for carrying out the above initial stop position control method, FIG. 3 is a partial external perspective view of an optical system, and FIG. 4 is a schematic block diagram of a control unit. Further, FIG. 5 is a diagram for explaining a speed control method of an optical system implemented in the copying machine, FIG. 6 is a diagram for explaining an operation during motor braking, and FIG. 7 is a flowchart showing an initial stop position control operation. is there. 2 ... Photosensitive drum, 3 ... Optical system, HPS ... Home position sensor, RE ... Rotary encoder, 38 ... Motor.

Front page continued (72) Inventor Yasumasa Oba, 3744 Ooka, Oka, Numazu City, Shizuoka Prefecture, Japan Domestic Electric Co., Ltd. (72) Inventor, Mitsuhiro Matsuoka, 3744, Ooka, Numazu City, Shizuoka, Japan (56) 59-171945 (JP, A) JP 58-105253 (JP, A) JP 57-111556 (JP, A) Actually opened 58-21152 (JP, U) Actually opened 56-80544 (JP, A) U) United States Patent 4568171 (US, A)

Claims (1)

[Claims] 1. A first initial stop mode in which the initial position is compared with the home position sensor position at the time of initializing the optical system such as when the power is turned on, and the initial position is on the stop position side with respect to the home position sensor position. In the case of, feed for a predetermined distance, then control the speed so that the speed is constant at the home position sensor position, and then return.
At the home position sensor position, the motor is braked from the constant speed to move to the stop position, and in the second initial stop mode in which the initial position is on the opposite side of the home position sensor position from the stop position, a predetermined value is set. When the home position sensor position reaches the constant speed at the time of return, the motor is braked from the constant speed at the home position sensor position to move to the stop position. If the home position sensor position does not reach the certain speed, the motor is braked at the home position sensor position to pass the position between the home position sensor position and the stop position and then the first initial stop. A method for controlling an initial stop position of an optical system of a copying machine, characterized by shifting to a mode.