JPH08146532A - Optical system unit driving device for copying machine - Google Patents

Abstract

PURPOSE: To prevent the generation of control delay or unstable rotational condition by adjusting load applied from a transmission mechanism to a motor so as to be conformed to a reference value prescribed according to the rotating speed. CONSTITUTION: One end of a timing wire 34 is wound on a winding pulley 5 through a spring 44. A sensor 7 detects one edge 6b of the slit 6a formed on a slit plate 6 as the home position of the winding pulley 5. When the winding pulley 5 is normally rotated in the arrow mark D direction by a stepping motor 2, the one end of the timing wire 34 is wound on the winding pulley 5, and the tension of the timing wire 34 increases. Meanwhile when the winding pulley 5 is reversely rotated in the arrow mark E direction, the wound timing wire 34 is separated from the winding pulley 5, and the tension of the timing wire 34 decreases. Therefore, the rising characteristic of rotation at starting the motor 2 can be always favorably maintained regardless of the target rotating speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system unit driving device of a copying machine which scans an image of an original with an optical system unit.

[0002]

2. Description of the Related Art Generally, in a copying machine, the light of a copy lamp is applied to a document, and the light reflected from the document is distributed to a photoconductor.
For example, as shown in FIG. 10, a fixed copyboard type copy machine includes a copy lamp 22, mirrors 23 to 28, and a lens 29 below the copyboard 21 on which the copy is placed. The light of the copy lamp 22 is reflected by the document placed on the document table 21, and is distributed to the surface of the photoconductor 30 via the mirrors 23 to 28 and the lens 29 as shown by the chain line in the figure. The photoconductor 30 rotates in the direction of arrow C, and the surface of the photoconductor 30 is charged by the charging charger 31 prior to the exposure by the reflected light from the document. An electrostatic latent image is formed on the surface of the photoconductor 30 by the exposure of the reflected light from the original, and the electrostatic latent image is visualized by the developing device 32 and then transferred onto the sheet by the transfer charger 33. .

In order to irradiate the light of the copy lamp 22 on the entire surface of the original placed on the original table 21 and distribute this light to the surface of the photoconductor 30 without changing the optical path distance, the copy lamp is used. 22 and the mirrors 23 to 27 must be horizontally moved to the document table 21 at a predetermined speed. Therefore, the copy lamp 22 and the mirror 23 are mounted on the copy lamp unit 39, and the mirrors 24 and 25 are mounted.
Is mounted on the first mirror base 40, the mirrors 26 and 27 are mounted on the second mirror base 41, and the timing wire 34 is fixed at one end to the fixing plate 43 and at the other end via the spring 44. There is.

The timing wire 34 half-circulates the movable pulley 37 from the fixed plate 43 to the fixed pulley 35, and is fixed to the copy lamp unit 39 during this period. After this, the timing wire 34 is fixed to the fixed pulley 35.
Is wound around the drive pulley 38 attached to the rotary shaft of the motor 42 a plurality of times, and reaches the movable pulley 37 via the fixed pulley 36, and is fixed to the first mirror base 40 in the meantime. The timing wire 34 reaches the spring 44 by half-circling the movable pulley 37 again. The timing wire 34 transmits the rotation of the motor 42 from the drive pulley 38 to the copy lamp unit 39 and the first mirror base 40 via the timing wire 34. The rotation of the motor (not shown) is transmitted to the second mirror base 41 on which the mirrors 26 and 27 are mounted.

Further, in order to change the copying magnification while keeping the rotation speed of the photosensitive member constant, it is necessary to change not only the lens 29 but also the scanning speed of the original, and therefore the copy lamp unit 39 and the first mirror base. 40 and the second mirror base 41 must be moved at a speed according to the copy magnification. Therefore, the rotation speed of the motor 42 is controlled to a different rotation speed according to the set copy magnification. This is to change the relative speed between the original scanning speed of the copy lamp 22 and the rotation speed of the photoconductor 30 to change the magnification in the original scanning direction.

As disclosed in Japanese Patent Laid-Open No. 62-198847, a timing belt is used instead of the timing wire as a transmission mechanism for transmitting the rotation of the motor to the copy lamp unit and the mirror base. Some used.

[0007]

In the optical system unit of the copying machine configured as described above, copying in which the rotational speed of the motor for driving the copy lamp unit and the first mirror base is strictly controlled is set. It is necessary to faithfully reproduce the magnification. In such a motor rotation control, generally, the motor rotation speed, which is a control amount, is compared with a target rotation speed for realizing the copy magnification set at that time, and the voltage applied to the motor, which is an operation amount, is controlled. Feedback control is performed. Disturbances in this feedback control include fluctuations in power supply voltage and motor load. Of these, the fluctuation of the power supply voltage causes almost no problem, but the optimum load to be applied to the motor differs depending on the target rotation speed. That is, when the target rotation speed is high, it is necessary to apply a relatively large load to the motor, and when the target rotation speed is low, it is necessary to apply a relatively small load. Specifically, it is necessary to change the tension of the timing wire, which is a transmission mechanism arranged between the motor and the optical system unit, according to the target rotation speed.

However, in the conventional copying machine, even when the rotation speed of the motor is changed according to the copy magnification, the load acting on the motor (for example, the tension of the timing wire).
Was kept constant, and therefore, when a load suitable for a comparatively low rotational speed is set, FIG.
As shown in, the motor's rotating shaft does not receive a sufficient load during image reduction when the motor rotates at high speed, a relatively large overshoot occurs at the start of motor rotation, and it takes a long time to converge to the target rotation speed. Need time.
On the other hand, when a relatively large load is generated in the transmission mechanism, as shown in FIG. 11B, a sufficient load acts on the rotation shaft of the motor during image reduction in which the motor rotates at high speed. It is possible to converge to the target rotation speed early from the start of the rotation of the motor, and to perform stable control, but at the time of image enlargement when the motor rotates at low speed, the load acting on the rotation shaft of the motor is too large and stable rotation can be obtained. May not be possible.

An object of the present invention is to set the load acting on the motor to a predetermined value according to the rotation speed when the rotation speed of the motor for driving the optical system unit changes according to the change of the copy magnification. As a result, it is possible to prevent the control delay and unstable rotation state due to the load that does not match the rotation speed from acting, and to perform the proper motor rotation control according to the copy magnification. An object of the present invention is to provide an optical system unit driving device of a copying machine that can obtain an image.

[0010]

According to a first aspect of the present invention, there is provided a motor for transmitting rotation to an optical system unit via a transmission mechanism, and the rotation of the motor varies depending on a set copy magnification. In an optical system unit driving device of a copying machine controlled to a speed, load detection means for detecting a load acting on a motor, and a detection result of the load detection means conforms to a reference value predetermined according to the rotation speed of the motor. Thus, the load adjusting means for increasing or decreasing the load acting on the motor from the transmission mechanism is provided. According to a second aspect of the present invention, the transmission mechanism is a timing wire that connects the rotation shaft of the motor and the optical system unit, and the load adjusting unit is a tension changing unit that increases or decreases the tension of the timing wire. It is characterized by

According to a third aspect of the present invention, a warning means is provided for urging a warning when the detection result of the load detection means does not match the reference value when the limit of the adjustment range of the load adjustment means is reached. Characterize that.

[0012]

According to the first aspect of the present invention, the load acting on the motor is detected by the load detecting means, and the detection result of the load detecting means conforms to a reference value predetermined according to the rotation speed of the motor. Thus, the load acting on the motor from the transmission mechanism is increased or decreased. Therefore, when the rotation speed of the motor is changed according to the set copy magnification, the load corresponding to the target rotation speed of the motor is adjusted so that it acts on the motor from the transmission mechanism, and the optimum value for the rotation speed target value is obtained. The rotation speed of the motor is controlled under the load.

In the invention described in claim 2, the rotation of the motor is transmitted to the optical system unit through the timing wire, and the load corresponding to the tension of the timing wire acts on the motor. Therefore, when controlling the rotation speed of the motor, by increasing or decreasing the tension of the timing wire, the optimum load for the target value of the rotation speed of the motor acts on the motor.

According to the third aspect of the present invention, the load acting on the motor conforms to the reference value according to the rotation speed even though the load adjusting means adjusts the load in the increasing or decreasing direction up to the limit of the adjusting range. If not, a warning will be issued. Therefore, the user recognizes that the copier must be adjusted or repaired to obtain a faithful scaled image.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a schematic structure of a main part of a copying machine to which an optical system unit driving device according to an embodiment of the present invention is applied. The difference between the figure and the optical system unit of the conventional copying machine shown in FIG. 10 is that the timing wire 3 whose one end is fixed to a fixing plate 43 in the conventional copying machine shown in FIG.
The other end of wire 4 is fixed to the device via a spring 44, whereas in the embodiment of the invention shown in FIG.
It is attached to the. Other configurations in FIG. 1 are the same as those in FIG. 10, and the same numbers as in FIG.

FIG. 2 is a diagram showing the structure of an actuator provided in the optical system unit of the copying machine. The actuator 1 includes a stepping motor 2, a worm roller 3 attached to a rotation shaft 2a of the stepping motor 2, a worm gear 4 meshing with the worm roller 3, and a winding pulley coaxially supported integrally with the worm gear 4. 5, the slit plate 6, and the sensor 7 facing the slit 6a of the slit plate 6. Stepping motor 2
The rotary shaft 2a of the rotary shaft 2a is rotatable in both forward and reverse directions.
The rotation of a is transmitted to the take-up pulley 5 and the slit plate 6 by the engagement of the worm roller 3 and the worm gear 4. Therefore, the winding pulley 5 and the slit plate 6 are rotated in both forward and reverse directions by driving the stepping motor 2. One end of the timing wire 34 is wound around the winding pulley 5 via a spring 44. The sensor 7 detects one edge 6b of the slit 6a formed in the slit plate 6 as the home position of the winding pulley 5.

Take-up pulley 5 driven by stepping motor 2
Is rotated in the direction of arrow D, one end of the timing wire 34 is wound around the take-up pulley 5 and the timing wire 34
Tension increases. On the other hand, when the take-up pulley 5 is rotated in the direction of arrow E, the wound timing wire 34 moves away from the take-up pulley 5, and the tension of the timing wire 34 decreases.

FIG. 3 is a block diagram showing a part of the control section of the copying machine. CP that controls the operation of each part of the copier
The U11 includes a ROM 12 and a RAM 13.
A program defining the operation of the CPU 11 is written in the ROM 12 in advance, and the CPU 11 centrally controls each input / output device in accordance with this program. RAM13
In this control, the data input / output to / from the CPU 11 is temporarily stored. Interface 1 to CPU 11
The stepping motor driver 14 and the motor driver 15 are connected via 7 and 18. The stepping motor driver 14 drives the stepping motor 2 that constitutes the actuator 1. Motor driver 15
Drives a motor 42 provided in the optical system unit.

The CPU 11 outputs the forward rotation signal S1 or the reverse rotation signal S2 to the stepping motor driver 14 via the interface 17. The stepping motor driver 14 rotates the stepping motor 2 forward (in the direction of arrow D shown in FIG. 2) or reversely (in the direction of arrow E shown in FIG. 2) based on the signals S1 and S2 input from the CPU 11. CPU
11 is a motor driver 15 via the interface 18.
Then, the scanning signal S3 corresponding to the copy magnification is output. The motor driver 15 supplies the voltage corresponding to the scanning signal S3 to the motor 4
2 is applied. The current flowing through the motor 42 is detected as a voltage value by the resistor R1 and is input to the CPU 11 via the A / D converter 17 as load data indicating the magnitude of the load acting on the motor 42. The CPU 11 outputs signals S1 and S2 to the stepping motor driver 14 based on the voltage data input from the A / D converter 17 by the processing described later.

An operation panel 16 is connected to the CPU 11 together with a motor driver for driving and controlling a motor for moving the lens 29, a driver for each device constituting the copy process section and the sheet transport path, and the like.

FIG. 4 is a flowchart showing a part of the processing procedure in the control section of the copying machine. When the warm-up after turning on the power is completed, the CPU 11 constituting the control unit waits for a key operation on the operation panel 16 (n1), and when the magnification conversion key is operated, an appropriate voltage level according to the set magnification is set. Read Vs (n2 →
n3). The relationship between the copy magnification and the appropriate voltage shown in FIG. 5 is stored in advance in the ROM 12 connected to the CPU 11, and the CPU 11 reads the appropriate voltage level Vs corresponding to the set copy magnification from the relationship shown in FIG. .

Next, the stepping motor driver 14
To output the signal S1 or S2 to the home position of the take-up pulley 5 based on the detection signal of the sensor 7 (n4). When moving the take-up pulley 5 to the home position, first, the output of the sensor 7 changes from the “Lo” level to the “High” level, or the take-up pulley 5 continues to take up a half turn. The pulley 5 is rotated in the forward direction (direction of arrow D in FIG. 2). The output of the sensor 7 changes from “Lo” to “Hi” until the take-up pulley 5 makes a half turn.
The position changed to the gh "level is the home position of the take-up pulley 5. When the output of the sensor 7 does not change until the take-up pulley 5 makes a half turn, the take-up pulley 5 is moved in the reverse direction. Rotate in the direction of arrow E in FIG.
The position where the output of the sensor 7 changes from the “High” level to the “Lo” level while the take-up pulley 5 is rotating in reverse is the home position of the take-up pulley 5. Thus, the reason why the take-up pulley 5 is not normally rotated over a half circumference or more is to prevent the take-up pulley 5 from being erroneously detected as a home position when the take-up pulley 5 makes one rotation from the home position.

When the movement of the take-up pulley 5 to the home position is completed, the counter C assigned to a predetermined memory area of the RAM 13 is cleared (n5). The counter C counts the number of drive pulses given to the stepping motor 2 with the home position of the winding pulley 5 as a reference. The CPU 11 identifies the rotational position of the winding pulley 5 based on the contents of the counter C. Thereafter, the CPU 11 drives the motor 42 (n6), reads the voltage data VL input from the A / D converter 17 (n7), and the read voltage data VL is centered on the proper voltage level Vs read in n3. It is determined whether or not it is within the allowable range Vs ± k (n8).

As shown in FIG. 6, when the read voltage level is not within the allowable range of the proper level, an error e between the voltage level and the proper voltage level is obtained (n9), and the error e shown in FIG. The correction pulse number is obtained based on the relationship with the pulse number Ps (n10). This error e and the correction pulse number P
The relationship with s is stored in the ROM 12 in advance. Figure 7
As shown in, the correction pulse number Ps has a negative value when the read voltage level is higher than the proper voltage level, and conversely, when the read voltage level is lower than the proper voltage level, the correction pulse number is low. The number Ps has a positive value.

The CPU 11 reads out the correction pulse number Ps
Is added to the content of the counter C (n11), and it is determined whether the content of the counter C is between the maximum value Pmax and the minimum value Pmin of the drive pulse number of the winding pulley 5 (n1).
2) If it is between the minimum value and the maximum value, the signal S1 or S2 is output to the stepping motor driver 14 in accordance with the correction pulse number Ps to cause the stepping motor 2 to rotate normally or reversely (n13). If the content of the counter C exceeds the maximum value or the minimum value, a warning is displayed on the liquid crystal display section of the operation panel 16 (n14). This warning display is displayed, for example, on the liquid crystal display section 51 provided on the operation panel 16 as shown in FIG. 』
Is displayed together with the trouble code. From n6 above
The process of n14 is continuously performed until the read voltage level falls within the allowable range of the proper voltage level, and if the read voltage level falls within the allowable range of the proper voltage level, the process returns to the standby state (n8 → n1). .

With the above processing, according to this embodiment,
The load acting on the motor 42 is detected as a voltage applied to the resistor R1, and the stepping motor 2 is driven to rotate normally or reversely based on the result of comparison between this voltage level VL and an appropriate voltage level Vs corresponding to the set copy magnification. By doing so, the tension of the timing wire 34 is increased / decreased so that the voltage level VL falls within the allowable range Vs ± k of the appropriate voltage level Vs, and the load according to the set copy magnification acts on the motor 42. Can be adjusted to.

FIG. 9 is a diagram showing a structure of an actuator of an optical system unit driving device of a copying machine according to another embodiment of the present invention. The actuator 61 of this embodiment includes a stepping motor 62, a friction belt 63 and a spring 64.
It is composed by. One end of the friction belt 63 is wound around the rotary shaft 62a of the stepping motor 62, and the other end is fixed to the device via a spring 64. The intermediate portion of the friction belt 63 is in contact with a part of the peripheral surface of the pulley 38 around which the wire 34 is wound a plurality of times.

When the actuator 61 is configured as described above, the contact force of the intermediate portion of the friction belt 63 with respect to the peripheral surface of the pulley 38 is increased or increased by rotating the stepping motor 62 forward or backward in the arrow F or G direction. The load acting on the motor 42 can be decreased or increased or decreased.

[0029]

According to the first aspect of the invention, the load of the motor for transmitting the rotation to the optical system unit that moves at different speeds depending on the copy magnification is determined by a predetermined reference corresponding to the copy magnification. By increasing or decreasing to match the value, the startup characteristics of rotation at motor startup can always be maintained well regardless of the target rotation speed, and stable control is performed at a rotation speed according to the set copy magnification. Therefore, it is possible to faithfully reproduce the original image by converting the magnification.

According to the second aspect of the present invention, the load acting on the motor can be easily adjusted by increasing or decreasing the tension of the timing wire that transmits the rotation of the motor to the optical system unit.

According to the third aspect of the present invention, when the load on the motor cannot be adjusted, the user can be made aware of the occurrence of the abnormality, and the malfunction of the device can be eliminated early. At the same time, the content of the copy processing can be performed in a state in which the original image cannot be faithfully scaled and copied.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an optical system unit of a copying machine to which an optical system unit driving device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a structure of an actuator that constitutes the optical system unit driving device.

FIG. 3 is a flowchart showing a part of a control unit of a copying machine to which the optical system unit driving device is applied.

FIG. 4 is a flowchart showing a processing procedure of a control unit of the copying machine.

FIG. 5 is a diagram showing a relationship between a copy magnification and a voltage level representing a load state of a motor in the optical system unit driving device.

FIG. 6 is a diagram showing an allowable range of an appropriate voltage level in the optical system unit driving device.

FIG. 7 is a diagram showing a relationship between a voltage level error and the number of correction pulses in the optical system unit driving device.

FIG. 8 is a diagram showing an example of a display screen on a display unit of a copying machine having the optical system unit driving device.

FIG. 9 is a diagram showing a structure of an actuator that constitutes an optical system unit driving device according to another embodiment of the present invention.

FIG. 10 is a schematic diagram showing a configuration of a conventional optical system unit driving device.

FIG. 11 is a diagram showing a rotation state of a motor in a conventional optical system unit driving device.

[Explanation of symbols]

 1-Actuator 2-Stepping Motor 3-Worm Roller 4-Worm Gear 5-Winding Pulley 6-Slit Plate 7-Sensor 34-Timing Wire 39-Copy Lamp Unit 40-First Mirror Base

Claims (3)

[Claims] 1. An optical system unit driving apparatus for a copying machine, comprising a motor for transmitting rotation to an optical system unit via a transmission mechanism, and controlling the rotation of the motor at different rotation speeds according to a set copy magnification. , Load detecting means for detecting the load acting on the motor, and the load acting on the motor from the transmission mechanism is increased or decreased so that the detection result of the load detecting means conforms to a predetermined reference value according to the rotation speed of the motor. An optical system unit driving device for a copying machine, comprising: load adjusting means. 2. The timing mechanism according to claim 1, wherein the transmission mechanism is a timing wire that connects the rotation shaft of the motor and the optical system unit, and the load adjusting means is a tension changing means that increases or decreases the tension of the timing wire. An optical system unit driving device of the copying machine described. 3. A warning means for urging a warning when the detection result of the load detection means does not conform to a reference value in a state where the limit of the adjustment range of the load adjustment means is reached is provided. Optical system unit driving device for copiers.