JP3782564B2 - Movement control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a movement control device that performs movement control of an object.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a copying apparatus that scans an original with a scanning device that performs a reciprocating operation, in order to accurately stop the scanning device that has reciprocated at the movement start position for the next reciprocating operation, the scanning device is restored to a predetermined position. Control that stops at the movement start position by starting the brake from when it moved was used. Since the control only needs to perform constant brake control at all times, it is possible to accurately return to the movement start position without complicating the apparatus.
[0003]
[Problems to be solved by the invention]
However, in this brake control, as the moving speed of the scanning device increases, the brake adjustment becomes difficult due to variations in the braking force of each motor. In addition, there is a high possibility that a problem that the vehicle cannot be stopped at the target stop position due to deterioration of the braking force due to the temperature rise of the motor.
[0004]
[Means for Solving the Problems]
In view of the above problems, the present invention provides a driving unit that moves a scanning device that performs a reciprocating operation for scanning an original, and a detection unit that detects that the scanning device has reached a predetermined position after the scanning device starts moving backward. And a speed detecting means for detecting that the speed of the scanning device has been reduced to a predetermined speed, and a first time after a predetermined time after the detecting means detects that the scanning device has reached the predetermined position. A first braking control means for performing braking, and after the speed detection means detects that the speed of the scanning device has been reduced to a predetermined speed after the start of braking by the first braking control means. A second braking control means for performing a second braking; and a speed of the scanning device is reduced to a predetermined speed after the detection means detects that the scanning device has reached the predetermined position. Speed detection A distance measuring means for measuring the moving distance of the scanning device until the stage is detected; and if the moving distance measured by the measuring means is larger than the target distance, it corresponds to the difference between the measured moving distance and the target distance. Reducing the predetermined time, and if the moving distance measured by the measuring means is smaller than the target distance, a correcting means for increasing the predetermined time according to the difference between the measured moving distance and the target distance, The present invention provides a movement control device characterized by having the above.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an outline of a copying apparatus showing an example of the present invention. 1 is an automatic document feeder, 2 is a scanning device (optical system) including a document illumination lamp, 3 is a photosensitive drum, 4 is a developing device, and 5 is a developing device. A transfer device, 6 is a fixing device, 7 is a paper storage, and 8 is a paper discharge tray. That is, after a document is placed on the automatic document feeder 1 and a desired copy mode is set on the operation panel, a copy operation is started by pressing a start key on the operation panel. The document placed on the automatic document feeder 1 is automatically conveyed to the scanning position. When the document is stopped at the scanning position, the scanning device 2 starts reading the document and forms an electrostatic latent image on the photosensitive drum 3. The electrostatic latent image is made visible with toner by the developing device 4 and transferred onto the recording paper conveyed from the paper storage 7 by the transfer device 5. Then, the toner is softened and melted and fixed on the recording paper by the fixing device 6, and is discharged to the paper discharge tray 8.
[0006]
FIG. 2 is a diagram showing the configuration of the scanning device. 10 is a motor for driving the scanning device 15, 11 is a sensor for detecting that the scanning device 15 has reached a predetermined position, and 12 is a scanning device 15. Is a sensor for detecting that the scanning position of the scanning device 15 has reached the leading edge of the document, and 14 is a document exposure lamp. In the present embodiment, the sensor 11 and the sensor 13 are separated from each other. However, when the respective positions are the same, one sensor may be detected. The sensors 11 to 13 include a light emitting unit and a light receiving unit attached to the inner wall of the copying apparatus main body, and a flag plate (a plate that does not transmit light) attached to the scanning device 15 passes between the light emitting unit and the light receiving unit. The detection signal is output to the CPU 44 when the light received by the light receiving unit is blocked.
[0007]
When the sensor 12 detects that the scanning device 15 is in the movement start position, the document exposure lamp 14 is turned on, and the scanning device 15 starts moving by driving the motor 10 at a speed corresponding to the copy setting magnification. The motor 10 and the lamp 14 are controlled so that a desired speed and a desired light amount are obtained before the sensor 13 detects the leading edge position of the document. Scanning is performed from the time when the sensor 13 detects the position of the leading edge of the document to the length corresponding to the document length and the copy setting magnification. When the scanning device 15 reaches the scanning end position, for the next scanning, the driving motor 10 is moved in the direction opposite to the scanning direction, and the sensor 11 detects that the scanning device 15 has reached the predetermined position. The scanning device 15 is moved back to the movement start position by controlling the drive so as to reach the speed.
[0008]
FIG. 3 is a block diagram showing a control configuration of the motor 10. Reference numeral 41 denotes an FG signal output from the drive motor (every time an FG magnet provided on the rotating element of the motor crosses an FG coil provided on the exterior of the motor). A frequency detector for detecting the frequency of the signal output from the FG coil), 42 a pulse number measuring device for measuring the number of FG signals (pulse number) within a predetermined time, and 11 for the scanning device 15 coming to a predetermined position. A position detection sensor 44 for detecting this is a CPU that controls the brake operation of the motor 10 and the operations of the frequency detector 41 and the pulse number measuring device 42.
[0009]
The FG signal output from the drive motor 10 is output to the trigger input terminal of the frequency detector 41 and the reference pulse signal input terminal of the pulse number measuring device 42, and the CPU 44 outputs to the reference pulse signal input terminal of the frequency detector 41. A pulse signal with a constant period is always input. The output signal of the frequency detector 41 is input to the CPU 44. In addition, a voltage is always applied to the trigger input terminal of the pulse number measuring device 42 and a high level is input.
[0010]
The drive motor 10 has two types of brake mechanisms with different control methods, and the first brake is a brake (hereinafter referred to as a reverse brake) that forcibly rotates the motor in a direction different from the current rotation direction. The second brake is a brake that short-circuits the electrodes at both ends of the motor (hereinafter referred to as a short brake). The reverse brake, which is the first brake, has a strong braking force and is optimal when the driving speed is lowered in a short time. However, if the braking operation is continued, the motor rotates in the reverse direction. Since the short brake, which is the second brake, has a weak braking force, the drive speed cannot be lowered in a short time, but the motor can be surely stopped while the brake operation is continued after the motor is stopped. A drive / brake control signal for the drive motor 10 is output from the CPU 44.
[0011]
FIG. 4 is a control flowchart of the CPU 44 when the scanning device 15 moves backward. Wait until scanning is completed (step 50). When scanning is completed, return to the movement start position is started (step 51). Next, it is detected whether or not the scanning device has reached a predetermined position by looking at the detection result of the sensor 11 (step 52). When it is detected that the scanning device has reached a predetermined position, the frequency detector 41 performs an initial setting of the frequency detector 41 via the address bus and the data bus and then detects that the predetermined frequency has been reached. (Step 53). As an initial setting value of the frequency detector 41, it is desirable to set a frequency corresponding to the motor speed at which the motor can be stopped immediately even in the deceleration force of the second brake of the motor. Then, after initializing the pulse number measuring device 42 via the address bus and the data bus, the pulse number measuring device 42 is started (step 54).
[0012]
Next, it is determined whether or not a predetermined time has elapsed since the predetermined position was detected (step 55), and after the predetermined time has elapsed, the first brake, that is, the reverse brake is operated (step 56). Next, it is detected whether or not the frequency of the motor FG signal has decreased to a predetermined frequency set, that is, whether or not the motor speed has decreased to a predetermined speed (step 57). Is switched from the first brake to the second or short brake (step 58). At this time, the end of the measurement pulse number and the instruction to latch (hold) the count value are output to the pulse number measuring device 42 via the address bus and the data bus (step 59). Specifically, data is written to an address in the pulse number measuring device 42 that receives a measurement end instruction, and then data is written to an address that receives a latch instruction. Then, the count value is input by writing data to an address that receives an instruction to read the latched count value and then reading the address where the latched data is stored.
[0013]
Next, the latched count value is compared with the target count value obtained by converting the target distance from the predetermined position detection to the brake switching position into the number of FG signal pulses (step 60), and if the measured number of pulses is larger. If it is determined that the actual moving distance is longer than the target distance, the process in step 61 is the same. If not, the actual moving distance is determined to be shorter than the target distance, and the process in step 62 is the same. If there is, it is determined that the stop position is as intended, and the process is terminated.
[0014]
In step 61, a time required for moving the difference distance between the target distance and the actual moving distance is calculated, and this time is determined as a predetermined time (step 55) from the detection of the predetermined position until the first brake is operated. Correction process for subtracting from (predetermined time). In step 62, as in 61, the time required to move the difference between the target distance and the actual moving distance is calculated, and this time is a predetermined time from the detection of the predetermined position until the first brake is operated. Correction processing to be added to (predetermined time in step 55) is performed. With this correction processing, when stopping at the next reading start position, it becomes possible to switch from the predetermined position detection to the second brake at the target position, and always at the same position as the scanning start device. It can be stopped. FIG. 5 is a diagram showing changes in the speed of the scanning device 15 and shows before and after correction of the first and second brake operation start timings and the first brake operation start timing.
[0015]
Next, details of the frequency detector 41 will be described. The frequency detector 41 is realized by connecting a counter capable of setting a count value as shown in FIG. This counter starts an operation of counting the number of pulses input from the reference pulse signal input terminal in response to the trigger signal input to the trigger input terminal. When a new trigger signal is input to the trigger input terminal during the count operation, the count operation is reset and a new count operation is started. When a preset count value is reached, a signal is output from the output terminal. That is, the frequency detector 41 counts the pulse signal from the CPU 44 until the next FG signal is output after the FG signal is output, and when the set count value is reached (the interval between the FG signals is a predetermined count). A signal is output from the output terminal when it is free enough to count. Therefore, the frequency detector 41 outputs a signal from the output terminal when it is decelerated to a speed sufficient to operate the second brake. Because of such a configuration, the period of the pulse signal input to the reference pulse signal input terminal is set to a period that can be sufficiently counted when the motor 10 is near a predetermined speed.
[0016]
FIG. 6 is an example of a flowchart showing control for detecting a desired signal frequency. Initially, as an initial setting, setting is made to start counting in response to the input of a trigger (step 20), and a count value for detecting that the predetermined speed described above has been set is set (step 21). When the set count value is counted, an H level signal is set to be output to the output terminal (step 22). Next, the rising edge of the trigger is waited (step 23), and when the trigger is inputted, the reference pulse signal counting operation is started (step 24). After the count is started, a determination is made as to whether or not the predetermined number of counts has been completed (step 25), and a process for determining whether or not a re-trigger is input is performed (step 26). The trigger is activated before counting to the predetermined count value. If it is input, the process returns to step 24, and the counting operation is started again from the beginning. If it is counted up to a predetermined count value before inputting the trigger, an H level signal is output to the output terminal (step 27).
[0017]
Next, the details of the pulse number measuring device 42 will be described. The pulse number measuring device 42 is realized by connecting the same counter as that used in the frequency detector 41 as shown in FIG. The pulse number measuring device 42 is configured to count the number of FG signals. An H level is always applied to the trigger input terminal, and the counter is not reset from this terminal. Further, the pulse number measuring device 42 does not use an output terminal. Instead, the count start of the pulse number measuring device 42 and the output of the count result are performed via the address bus and data bus.
[0018]
FIG. 7 is a flowchart showing control for counting the number of pulses of the pulse signal. Initially, as an initial setting, when an H level signal is input to the trigger input terminal, a setting is made so that the count operation is always possible (step 32). Next, the CPU 44 waits for a count number measurement start request (step 33). When a count number measurement start request is detected, an initial count value is set in the counter (step 34). The initial count value is set to 0 when the counter is operated as an up counter, and when the counter is operated as a down counter, a value that does not end the count from the count start request to the count end request is set. Keep it. Then, counting up or counting down is performed according to the input of the FG signal (step 35). Thereafter, the CPU 44 waits until a count end request is received from the CPU 44 (step 36). If there is an end request, the count operation is ended (step 37).
[0019]
【The invention's effect】
As described above, according to the first aspect of the present invention, the driving unit that moves the scanning device that performs the reciprocating operation for scanning the document, and the scanning device reaches a predetermined position after the backward movement of the scanning device is started. Detecting means for detecting that the speed of the scanning device has been reduced to a predetermined speed, and detecting means for detecting that the scanning device has reached the predetermined position. A first braking control means for performing a first braking after a predetermined time, and the speed detection means that the speed of the scanning device has been reduced to a predetermined speed after the start of the braking by the first braking control means. A second braking control means for performing a second braking in response to the detection, and a speed of the scanning device after the detection device detects that the scanning device has reached the predetermined position. Decelerated to speed A distance measuring means for measuring the moving distance of the scanning device until the speed detecting means detects that the movement is detected, and if the moving distance measured by the measuring means is larger than a target distance, The predetermined time is reduced according to the difference with the target distance, and if the movement distance measured by the measuring means is smaller than the target distance, the predetermined time is set according to the difference between the measured movement distance and the target distance. Therefore, even if the braking characteristic varies or the braking characteristic changes, stop control can be performed accurately.
[0021]
According to the second aspect of the invention, in addition to the first aspect, the driving means is a motor, the first brake is a reverse brake, and the second brake is a short brake. It can be stopped accurately.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a copying apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of a scanning device of a copying apparatus.
FIG. 3 is a control block diagram of a motor for driving the scanning device.
FIG. 4 is a control flowchart when the scanning device moves backward.
FIG. 5 is a diagram showing a change in speed of the scanning device.
FIG. 6 is a control flowchart regarding the frequency detector.
FIG. 7 is a control flowchart regarding a pulse number measuring device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Motor 11 Sensor 15 Scanning device 41 Frequency detector 42 Pulse number measuring device 44 CPU

Claims (4)

Driving means for moving a scanning device that performs a reciprocating operation for scanning an original ;
Detecting means for detecting that the scanning device has reached a predetermined position after the scanning device starts moving backward ;
Speed detecting means for detecting that the speed of the scanning device has been reduced to a predetermined speed;
A first braking control means the scanning device Ru to perform the predetermined time after the first brake that has reached the predetermined position from the detected said detecting means,
After the start of braking by the first brake control unit, a second brake control for the speed of the scanning device is performed a second braking in response to said speed detection means that the speed is reduced to a predetermined speed is detected Means,
The moving distance of the scanning device from when the detecting means detects that the scanning device has reached the predetermined position until the speed detecting means detects that the speed of the scanning device has been reduced to a predetermined speed Distance measuring means for measuring
If the moving distance measured by the measuring means is larger than the target distance, the predetermined time is reduced according to the difference between the measured moving distance and the target distance, and the moving distance measured by the measuring means is the target distance. Smaller than the correction means for increasing the predetermined time according to the difference between the measured moving distance and the target distance;
A movement control device comprising:   2. The movement control apparatus according to claim 1, wherein the driving means is a motor, the first braking is a reverse brake, and the second braking is a short brake.   The speed detecting means counts the number of pulse signals generated in a predetermined cycle, and includes a counter that is reset in response to a signal output every time the object moves by a predetermined amount, and counts a preset count value. The movement control device according to claim 1, wherein the movement control device detects that the speed of the object has been reduced to a predetermined speed. 2. The movement control apparatus according to claim 1, wherein the distance measuring unit includes a counter that counts a signal output every time the scanning apparatus moves by a predetermined amount.

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