JP2004231373A - Belt drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt drive device capable of automatically restoring running of a belt which stops if there is no abnormality in the belt and a position detection sensor and giving alarm without restoring the belt automatically if it is determined that a belt itself is broken even when a belt breakage prevention means operates and running of the belt stops. <P>SOLUTION: This belt drive device is provided with a means for determining that the belt breakage prevention means operates, a means for storing the number of operation of the belt breakage prevention means, an automatic restoration means for resuming drive of the endless belt, and an abnormality alarm giving means. When the breakage prevention means operates, this device performs automatic restoration operation of the belt and gives alarm for abnormality when the breakage prevention means operates by the specified number. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a belt driving device that prevents damage to a belt when the belt is extremely shifted to one side due to a malfunction of a sensor, and that automatically returns the running of the belt. For example, in an image forming apparatus using an electrophotographic method, various belt-shaped members such as a photoreceptor belt, an intermediate transfer belt, a paper transport belt, and a fixing belt are used. It is. Further, the present invention can be applied not only to the image forming apparatus but also to any apparatus having a mechanism for driving the belt.
[0002]
[Prior art]
In the image forming apparatus, various endless belts, for example, a photoreceptor belt, an intermediate transfer belt, and a paper transport belt are used. Such an endless belt is supported and rotated by a plurality of rollers such as a driving roller. However, in addition to the velocity component in the rotational direction, the roller also has a velocity component in the axial direction of the roller due to the difference in the circumference of the belt, the dimensional accuracy of the roller supporting the belt, and the like. If no control is performed, the velocity component in the axial direction remains in one direction, and the belt moves to one side and breaks.
[0003]
Various means for controlling such a deviation of the belt toward one side have been introduced. Examples of the means include a method of operating the steering roll by detecting the amount of meandering of the belt (for example, see Patent Document 1), a method of providing a guide member that comes into contact with the belt end (for example, see Patent Document 2), and a method in which the end is located at the center. There is a method (for example, see Patent Literature 3) of preventing meandering by using a roller having a larger diameter than that of the roller. In the method of operating the steering roll by detecting the meandering amount, it is necessary to accurately detect the position of the belt and the moving speed in the axial direction, and to adjust the correction amount of the steering roller based on the detected value. As a sensor that can be used for position detection, a sensor that uses light including a light emitter that irradiates light and a light receiver that receives measurement light from the light emitter is generally used (for example, see Patent Document 4). When various types of sensors are used, if the sensors do not function properly, it is not possible to correct the meandering. Therefore, it is necessary to provide an emergency stop means.
[0004]
As one method, when the belt end detection sensor that operates due to contact with the belt stops functioning due to some abnormality, the lever supporting the belt end detection sensor turns on the abnormality detection sensor switch, and the belt There is a configuration that stops traveling (for example, see Patent Document 5).
[Patent Document 1]
JP 10-139202 A [Patent Document 2]
JP-A-11-208842 [Patent Document 3]
JP-A-10-129822 [Patent Document 4]
Japanese Patent Application Laid-Open No. H11-272094 [Patent Document 5]
Japanese Patent Application Laid-Open No. Hei 5-201578
[Problems to be solved by the invention]
As a case where the running of the belt is stopped by meandering, there is a case where the belt itself is damaged and control cannot be performed. In this case, the belt itself needs to be replaced. On the other hand, there is a case where the belt itself is not in trouble, but becomes abnormal, for example, the belt position is gradually deviated due to an error of the position detection sensor or the meandering correction means and the abnormality is detected. In the related art, in this case, the user or the maintenance person must manually return the belt to the original position according to the manual.
[0006]
In the present invention, even when the belt break prevention means is operated and the running of the belt is stopped, if there is no abnormality in the belt or the position detection sensor, the running of the stopped belt is automatically returned, and the belt itself is damaged. An object of the present invention is to provide a belt drive device that does not perform an automatic return operation when the determination is made and issues an abnormality warning and does not automatically return.
[0007]
[Means for Solving the Problems]
The object is to detect an endless belt, a drive roller for driving the endless belt, a drive motor for rotating the drive roller, a plurality of rollers for stretching the endless belt, and a position of an end of the endless belt. A position detection sensor that is not in contact with the endless belt, meandering correction means that corrects the movement of the endless belt in the roller axis direction based on the detection result of the position detection sensor, When the end of the endless belt comes into contact with the endless belt, the endless belt stops running by preventing the endless belt from moving.In a belt drive device, a means for determining that the belt damage prevention unit has operated. Means for storing the number of operations of the belt damage prevention means, automatic return means for resuming driving of the endless belt, and abnormality warning means, It performs an automatic return operation during the operation of the breakage preventing means, when the breakage preventing means has operated a prescribed number of times is achieved by alerting an abnormality.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a belt driving device for explaining an embodiment of the present invention viewed from above. Reference numeral 1 denotes a photoreceptor belt used in an image forming apparatus using an electrophotographic method, which moves downward at a speed Vx in FIG. The photosensitive belt 1 has a velocity component (Vy) in the right (or left) direction in FIG. Reference numeral 2 denotes a driving roller for rotating the photosensitive belt 1 to run. Reference numeral 3 denotes a tension roller for applying tension to the photoreceptor belt 1. Reference numeral 4 denotes a support roller for stretching the photosensitive belt 1. Reference numeral 5 denotes a position detection sensor for detecting the position of the end of the photosensitive belt 1. Reference numeral 6 denotes a spring for changing the tension applied to both ends of the photoreceptor belt 1. Reference numeral 7 denotes a belt damage preventing means. Reference numeral 8 denotes a power supply for driving the driving roller 2. Reference numeral 9 denotes a belt drive motor for driving the drive roller 2. Reference numeral 10 denotes a control unit which processes information from the position detection sensor 5 and the belt damage prevention means 7 and outputs signals to the spring 6 and the belt drive motor 9 to control the meandering of the photosensitive belt 1 and stop the running of the photosensitive belt 1. Control for automatic recovery when
[0009]
FIG. 2 is a schematic diagram of the position detection sensor 5. The position detecting sensor 5 includes a light emitting device 51 that emits light and a light receiving device 52 that receives light. The position detecting sensor 5 detects the position of an object in the sensor, for example, the end of the photosensitive belt 1 from the ratio of the amount of received light to the amount of emitted light. . Since the position detection sensor 5 is used in a non-contact manner, it is desirable that the installation position is such that the belt travel path does not change even if the way of applying tension by the tension roller 3 changes. In the present invention, the position detection sensor 5 is provided on the transport path formed by the driving roller 2 and the tension roller 3. In the present apparatus, meandering correction is performed by changing the force of the spring 6 pulling the tension roller 3, that is, the spring 6 serves as meandering correction means.
[0010]
Next, the operation principle from the stop of the driving of the photoreceptor belt 1 to the automatic return will be described. FIG. 3 is a diagram showing an operation circuit when the photosensitive belt 1 is running normally. The power supply 8 has a drive line A connected to the belt drive motor 9 via two belt breakage preventing means 7 and a drive line B directly connected to the drive motor 9. By providing the two drive lines in this way, when the damage prevention means 7 functions, the drive of the photosensitive belt 1 can be resumed by switching from the drive line A to the drive line B, and automatic return is possible. Become. Further, the two belt damage prevention means 7 are connected to the control unit 10 so that it is possible to know which belt damage prevention means 7 has operated, and the control unit 10 stores the number of times of operation and the time of operation. Usually, the photoreceptor belt is driven by a drive line A. The control unit 10 controls the photosensitive belt 1 so as to approach a predetermined position.
[0011]
FIG. 4 is a diagram showing an operation circuit when the photoreceptor belt 1 is moved to the end and the belt damage prevention means 7 operates. First, a mechanism for switching the drive line of the photosensitive belt 1 from the drive line A to the drive line B will be described. The belt drive motor 9 is provided with a speed measuring device 91 for measuring the running speed of the photoreceptor belt 1, and the information is always sent to the control unit 10. When the speed measured by the speed measuring device 91 is within a predetermined speed range, the control unit 10 operates the spring 6 based on the position information of the photoreceptor belt 1 coming from the position detection sensor 5 to set a predetermined predetermined speed. Is controlled so as to approach the position. The range of the amount of extension of the spring 6 and the range of the output value of the position detection sensor 5 when the photosensitive belt 1 is running stably within a predetermined range is stored. Even when the photoreceptor belt 1 is running stably, the meandering correction control functions, and the photoreceptor belt 1 is disconnected within a certain minute range. Therefore, the stored elongation amount and the output value of the position detection sensor 5 are also within a certain range. Is the value with.
[0012]
When the photoreceptor belt 1 pushes the damage prevention means 7 and the belt driving is stopped, the measured value of the speed measuring device 91 for measuring the traveling speed of the photoreceptor belt 1 is out of a predetermined speed range, and the information is sent to the control unit 10. Can be The control unit 10 that has obtained the information that the movement of the photoreceptor belt 1 has stopped stops changing the amount of extension of the spring 6 so as to shift to the opposite side. Next, a signal for switching the switch of the power supply 8 is transmitted from the control unit 10, and the power supply 8 is directly connected to the belt drive motor 9. With the above configuration, the drive line of the belt is switched from drive line A to drive line B.
[0013]
Next, a mechanism from switching of the drive line to returning to normal traveling will be described. When the drive line is switched, the photoreceptor belt 1 starts running and starts moving to the opposite side, and the output value of the position detection sensor 5 becomes the median of the range of the output value of the position detection sensor 5 stored in the control unit 10. Is reached, the running of the photoreceptor belt 1 is stopped, and the amount of extension of the spring 6 is returned to the median of the range of the amount of extension stored in the control unit 10. At this time, in order to prevent the photoreceptor belt 1 from suddenly shifting to the opposite side, the running speed when the running is restarted is set to be lower than the normal running speed. Next, the drive line is returned from drive line B to drive line A. Thereafter, the photoreceptor belt 1 is run at a normal speed for a predetermined time, and an operation for confirming that the photoreceptor belt 1 can run normally is performed. When the stable running can be performed within the predetermined time, the printing operation interrupted by the stop of the photosensitive belt 1 is restarted. When printing is resumed without performing this checking operation, if the photoreceptor belt 1 is shifted to the end again and stopped, several useless recording materials are generated. The confirmation work is to prevent this. If the stable operation cannot be performed in the checking operation, the belt 1 stops again and the automatic return operation is performed again. In the case where the damage prevention means 7 operates even if the automatic return operation is continuously performed a predetermined number of times, an error display is performed for the first time and an instruction such as calling a service center is issued.
[0014]
With the above operation, even if the photosensitive belt 1 is stopped at the end, the photosensitive belt 1 automatically restarts running and can resume printing. Further, it is possible to omit the operation of manually performing the belt return operation by the operator even if no failure occurs.
[0015]
The belt-shaped members in the electrophotographic apparatus include, in addition to the photoreceptor belt 1, a paper transport belt for adsorbing and holding a recording material, an intermediate transfer belt and a fixing belt for primarily transferring an image from a photoreceptor. These belts are made of an elastic material such as PET or polyimide, and have different circumferential lengths at both ends. In addition, when tension is applied and stretched, elongation occurs. It also expands and contracts due to temperature and humidity. Therefore, the amount of extension of the spring 6 when the belt stored in the control unit 10 is running stably changes every moment. Therefore, when the belt member is replaced, at regular intervals after the tension is applied, and when the temperature and humidity of the environment change by a predetermined value, the belt stored in the control unit 10 is running stably. It is desirable to update the range of the amount of extension of the spring 6 at the time.
[0016]
Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 6 is an example of a belt driving device supported by a driving roll 2, a tension roll 3, and one support roll 4, and FIG. 5 is a diagram of FIG. 6 as viewed from the left side in the transport direction of the photosensitive belt 1. It is. In this belt conveying device, the meandering correction means is a spring 6, and changing the set value of the spring 6 changes the inclination of the tension roller 3 and changes the tension applied to both ends of the belt 1, thereby correcting the meandering of the belt.
[0017]
In FIG. 5, a solid line indicates a traveling route when the photosensitive belt 1 is normally conveyed, and a dashed line and a two-dot chain line indicate the left end of the photosensitive belt 1 when the damage preventing means 7 is operated by one end of the belt. The traveling route is shown. When the photoreceptor belt 1 is shifted to the left side in the transport direction, the tension applied to the left end of the tension roll 3 becomes smaller than the right end, and the traveling path becomes a path indicated by a dashed line, and the traveling path moves to the right side in the transport direction. In the case of offset, the path is indicated by a two-dot chain line. When the photoreceptor belt 1 is supported by three or more rolls, by changing the tension applied to the tension roll 3 as shown in FIG. Can do things. By installing the breakage preventing means 7 on the side where the traveling route changes, the photosensitive belt 1 can be automatically returned to the normal position without changing the drive line of the photosensitive belt 1 as shown in FIG. Hereinafter, the mechanism will be described.
[0018]
FIG. 7 is a diagram showing the belt drive device viewed from the top (a, d, g) and the side view (b, e, h) and the state (c, f, i) of the damage prevention means 7. is there. (A), (b), and (c) show the state in which the photoreceptor belt 1 is normally running, (d), (e), and (f) show the state in which the photoreceptor belt 1 is offset and the breakage preventing means 7 is in operation. (g), (h), and (i) show a state in which tension is applied in a direction to return the photoreceptor belt 1 to a normal position in accordance with the operation of the breakage preventing means 7. The photoreceptor belt 1 is transported downward toward the drawing.
[0019]
When the position detection of the photoconductor belt 1 cannot be performed due to a malfunction of the position detection sensor 5 or the like, the photoconductor belt 1 starts to shift to the right as viewed in the drawing, for example, as illustrated in FIG. When the offset limit is reached, as shown in FIG. 7 (f), the belt damage prevention means 7 operates and the photosensitive belt 1 stops. Next, it is determined which of the two damage prevention means 7 has operated, and the tension applied to the tension roller 3 is controlled. In the case of FIG. 7, since the belt damage prevention means 7 on the right side of the drawing has been operated, a signal for reducing the tension applied to the left side of the photosensitive belt 1 in the drawing as shown in FIG. 7G is output, and the tension roller 3 tilts clockwise. . As a result, as shown in FIG. 7H, the conveyance path of the photosensitive belt 1 formed by the tension roller 3 and the support roller 4 tends to change from a broken line to a solid line. As a result, the conveyance path of the belt also changes as shown in FIG. 7 (i), the operation of the damage prevention means 7 is released, the drive of the drive motor 9 is restarted, and the photosensitive belt 1 is subjected to meandering correction. Driving automatically resumes.
[0020]
【The invention's effect】
According to the present invention, even when the belt breakage prevention means operates and the belt stops running, if there is no abnormality in the belt or the position detection sensor, the stopped running of the belt is automatically restored, and the belt itself is damaged. It is possible to provide a belt drive device that does not perform an automatic return operation when it is determined to have occurred, issues an abnormality warning, and does not automatically return.
[Brief description of the drawings]
FIG. 1 is a plan view of a belt driving device according to an embodiment of the present invention.
FIG. 2 is a side view of the position detection sensor in FIG.
FIG. 3 is a block diagram showing a belt drive system when the belt is running normally.
FIG. 4 is a block diagram showing a belt drive system from when the belt drive stops to when it returns.
FIG. 5 is a partial side view showing another embodiment of the present invention.
FIG. 6 is a plan view of a belt driving device according to another embodiment of the present invention.
FIG. 7 is an operation explanatory diagram from when the belt damage prevention means operates to when the belt returns to the original position.
[Explanation of symbols]
1 is a photoreceptor belt, 2 is a drive roller, 3 is a tension roller, 4 is a support roller, 5 is a position detection sensor, 6 is a spring, 7 is a belt breakage prevention means, 8 is a power supply, 9 is a belt drive motor, and 10 is a belt drive motor. A control unit, 51 is a light emitting unit, and 52 is a light receiving unit.

Claims (9)

An endless belt, a drive roller for driving the endless belt, a belt drive motor for rotating the drive roller, a plurality of rollers for stretching the endless belt, and the endless belt for detecting a position of an end of the endless belt. A position detection sensor that is not in contact with the belt, a meandering correction unit that corrects the movement of the endless belt in the roller axis direction based on the detection result of the position detection sensor, and the endless belt is extremely deviated to one side. When the end of the endless belt comes into contact with the endless belt, the end of the endless belt stops running. Means for storing the number of operations of the damage prevention means, automatic return means for resuming driving of the endless belt, and abnormality warning means; Performs an automatic return operation during the operation of the stop means, when said breakage preventing means has operated a prescribed number of times the belt drive, characterized in that the warning of abnormality. The drive motor has two drive lines, a line A connected to a power supply via two belt damage prevention means and a line B directly connected to a power supply. When the damage prevention means operates, the drive motor is driven. 2. The belt driving device according to claim 1, wherein the drive of the endless belt is automatically returned when the line is switched from the line A to the line ゛ line B. 2. A control unit for receiving a signal indicating the operation of the breakage prevention unit and changing a set value of the meandering correction unit so that the endless belt can automatically return to a predetermined position. Or the belt drive device according to 2. The control unit stores a set value of the meandering correction unit when the endless belt is stably rotating at a predetermined position. A belt drive device according to item 1. When the endless belt is replaced, the set value of the meandering correction means stored in the control unit is erased, and after the endless belt is replaced, at the time of the first rotating travel operation, the endless belt is rotated again stably. 5. The belt driving device according to claim 1, wherein a set value of the meandering correction means for causing the meandering correction means to be stored is stored again. After turning on the power of the belt drive motor, after the ambient temperature has changed by a certain value, after the environmental humidity has changed by a certain value, and after the endless belt has been stretched, at regular time intervals, the meandering correction is performed by any one or a plurality of times. 6. The belt driving device according to claim 1, wherein a set value of the means is stored again. 7. The running speed of the endless belt resumes after the breakage preventing means operates and the endless belt stops, and the running speed is lower than a normal running speed. Belt drive. The belt according to any one of claims 1 to 7, wherein the endless belt is a photosensitive belt, a transfer conveyance belt, an intermediate transfer belt, and a fixing belt used in an electrophotographic apparatus. Drive. Endless belt, a driving roller for driving the endless belt, a plurality of rollers for stretching the endless belt, a position detection sensor that is in non-contact with the endless belt for detecting the position of the end of the endless belt, Meandering correction means for correcting the movement of the endless belt in the axial direction of the roller based on the detection result of the position detection sensor, and when the endless belt is extremely deviated to one side, the end of the endless belt contacts And a belt driving device in which the running path of the endless belt changes according to a set value of the meandering correction means, when the endless belt is biased to one side, the damage is prevented. A belt driving device wherein an end of the endless belt that comes into contact with a prevention means changes a traveling route according to a set value of the meandering correction means.

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