JP5251309B2 - Belt misalignment correction apparatus and image forming apparatus including the same - Google Patents

Description

  The present invention relates to a belt deviation correction device that has an endless belt that is wound around a plurality of rollers and is driven to travel, and that prevents or corrects the movement of the belt due to the belt deviation of the endless belt. More specifically, the present invention relates to a belt deviation correction device that is advantageous in terms of cost because the apparatus can be miniaturized and the number of parts can be reduced. In addition, a belt device that uses the belt deviation correction device, and The present invention also relates to an image forming apparatus such as a printer, a copying machine, and a fax machine using the belt device.

  In a conventional image forming apparatus, various endless belts are used as a latent image carrier, an intermediate transfer member, a recording medium conveying member, an image fixing member, or the like. This type of endless belt is configured to run in a fixed direction while being stretched by at least two rollers. However, if the belt runs, the belt will break if there is meandering or offset. There is a risk that an appropriate image cannot be obtained due to image misalignment. Therefore, it is necessary to regulate or correct the deviation of the belt.

  As a conventionally known belt deviation correction device, a rubber or other guide rib is provided at the end of the back surface of the belt, and the guide rib is regulated by a roller end or groove, or a flange is provided at the roller end. A device that directly regulates the belt end face is known.

  In this type of belt shift correction device, the belt end may run over, the guide rib may be peeled off, or the belt end may be damaged due to variations in the belt shift amount. Therefore, the life of the belt or the belt deviation correction device also contributes to determining the life of the image forming apparatus. In such a belt deviation correction device, high component accuracy is required to suppress the belt deviation amount as much as possible. Need arises. Furthermore, since this is a major factor in determining the life of the image forming apparatus, an optimum belt material having excellent mechanical durability must be selected, leading to an increase in the cost of the apparatus. In order to solve such problems, various belt deviation correction devices and methods have been proposed.

  For example, in the belt misalignment correction apparatus or method described in Patent Document 1, a technique is disclosed in which the rib on the back surface of the belt rotates by passing between the contact bodies and the roller shaft is tilted via the link mechanism. Japanese Patent Application Laid-Open No. H11-228561 discloses a technique for inclining the roller by moving a rib provided on the roller end or a belt end member. In addition, Patent Document 3 discloses a technique in which a detection ring for detecting a belt shift is provided, and a roller shaft is tilted by using torque generated when the belt end portion rides on the detection ring. Furthermore, many techniques for detecting the position of the belt using a sensor and applying displacement to the roller shaft using a drive source have been proposed and are now commercialized.

  However, as in the techniques disclosed in the above-mentioned patent documents and the like, when the belt on which the belt is stretched is inclined to correct or prevent the deviation of the belt, the control roller, that is, the deviation of the belt is controlled. Since it is necessary to provide the steering roller for doing separately, there exists a problem that it leads to the increase in a number of parts and the enlargement of an apparatus.

JP 2005-92153 A JP 2006-162659 A Japanese Patent Laid-Open No. 2000-272772

  In light of the above problems, the object of the present invention is a belt misalignment correction device that can reduce the size of the device by providing a plurality of functions to one roller, and can reduce the number of parts. It is an object of the present invention to provide a belt deviation correction device that is advantageous in terms of belt.

The above problem is in accordance with the present invention.
A belt deviation correction device that has an endless belt that is wound around a plurality of rollers and driven to travel, and corrects the belt deviation of the endless belt,
At least one of the plurality of rollers is configured as a tiltable steering roller,
The steering roller is configured to tilt in advance in one direction when the endless belt travels by inclining a roller shaft of the steering roller in advance.
At one end of the steering roller, a roller shaft displacement member capable of changing the tilt angle of the roller by displacing the one end side with the other end side of the steering roller as a fulcrum according to the shift amount of the endless belt Is provided,
In the belt deviation correction device in which the roller shaft displacement member tilts the steering roller at an angle that balances the inclination of the steering roller due to the deviation of the endless belt,
The steering roller is a roller facing a cleaning member that cleans the surface of the belt,
The cleaning member for cleaning the surface of the endless belt is inclined integrally with the steering roller in accordance with the inclination of the steering roller; and
A cleaning device in which the cleaning member is disposed is further provided;
The cleaning device has a discharge port for discharging the removed material when the cleaning member cleans the belt surface to the outside of the cleaning device , and the discharge port is provided on the other end side.
This is solved by a belt deviation correcting device characterized in that the roller shaft displacement member is provided on the one end side.

  In the present invention, it is proposed that the steering roller is a roller having the longest belt winding amount among driven rollers excluding a driving roller for driving the endless belt in the plurality of rollers.

  Further, in the present invention, the steering roller is provided with an auxiliary member that assists in changing the tilt angle of the steering roller when the tilt angle of the steering roller is changed according to the shift of the endless belt. suggest.

Furthermore, in the present invention, in the belt device using the belt deviation correcting device according to any one of claims 1 to 3 , the belt is a photosensitive belt, an intermediate transfer belt, or a transfer material conveying belt used in an image forming apparatus. Alternatively, it is proposed that the image forming apparatus is a fixing belt, and further, an image forming apparatus including the belt device according to any one of claims 4 to 7 is proposed.

  According to the present invention, it is not necessary to newly provide a dedicated steering roller capable of tilting the roller shaft in order to correct the belt shift, and since the steering roller is provided with a plurality of functions, the number of parts can be reduced. As a result, it is possible to provide a belt misalignment correction apparatus that can reduce the size of the apparatus. Further, it is possible to provide a belt apparatus and an image forming apparatus that can be reduced in size and cost using the belt deviation correction apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing a tandem-type indirect (intermediate) transfer type electrophotographic apparatus to which a belt deviation correcting apparatus of the present invention is applied as an embodiment of an image forming apparatus of the present invention. The electrophotographic apparatus, which is an image forming apparatus shown here, includes a plurality of photoreceptors arranged in the main body casing, and in the illustrated example, first to fourth photoreceptors 1a, 1b, 1c, and 1d are provided. It has been. Toner images of different colors are formed on the respective photoreceptors. In the example shown in FIG. 1, a black toner image, a magenta toner image, and a cyan toner image are formed on these photoreceptors 1a, 1b, 1c, and 1d. And a yellow toner image are formed. Each of the photoconductors 1a, 1b, 1c, and 1d shown in FIG. 1 is formed in a drum shape, but an endless belt-like photoconductor that is wound around a plurality of rollers and driven to rotate can also be used. .

  An intermediate transfer belt 10 configured as an intermediate transfer member is disposed opposite to the first to fourth photosensitive members 1a, 1b, 1c, and 1d, and each of the photosensitive members 1a, 1b, 1c, and 1d is disposed on the intermediate transfer belt 10. It is in contact with the surface. The intermediate transfer belt 10 shown here is wound around support rollers 12, 13, 14, 15 and is configured as a drive roller in which one of these support rollers is driven by a drive device (not shown), When the drive roller is driven, the intermediate transfer belt 10 is driven to rotate counterclockwise in the drawing. The intermediate transfer belt 10 may have a multilayer structure or a single layer structure. However, if the intermediate transfer belt 10 is a multilayer structure, the base layer is made of, for example, a fluororesin, PVDF sheet, or polyimide resin with little elongation, and the surface is smooth such as a fluororesin. What is covered with a good coat layer is preferable. Moreover, if it is a single layer, what uses materials, such as PVDF, PC, a polyimide, is good. In the present invention, it is not necessary to specify the material of the intermediate transfer belt 10 in particular.

  The configuration for forming a toner image on the photoreceptors 1a, 1b, 1c, and 1d is substantially the same as the configuration for transferring each toner image onto the intermediate transfer belt 10, and the color of each formed toner image is the same. Is only different. Therefore, only the configuration and operation for forming a black toner image on the first photoreceptor 1a and transferring the toner image onto the intermediate transfer belt 10 will be described. The photoconductor 1a is rotated in the clockwise direction as shown by the arrow in FIG. 1, and at this time, the surface of the photoconductor is irradiated with light from a static eliminator (not shown), and the surface potential of the photoconductor 1a is initialized. The The initialized photoreceptor surface is uniformly charged by the charging device 4 to a predetermined polarity, in this example, a negative polarity. The charged surface is irradiated with a light-modulated laser beam 5 emitted from an exposure apparatus (not shown), and an electrostatic latent image corresponding to writing information is formed on the surface of the photoreceptor 1a. In this embodiment, an exposure apparatus including a laser writing apparatus that emits the laser beam 5 is used. However, an exposure apparatus having an LED array and an image forming unit may be used.

  The electrostatic latent image formed on the photoreceptor 1a is visualized as a black toner image when it passes through the developing device 6. On the other hand, on the inner side of the intermediate transfer belt 10, a transfer roller 27 is disposed so as to face the photoreceptor 1a with the belt interposed therebetween. The transfer roller 27 is in contact with the back surface of the intermediate transfer belt 10 to ensure an appropriate transfer nip between the photoreceptor 1a and the intermediate transfer belt 10.

  The transfer roller 27 is applied with a transfer voltage having a polarity opposite to the toner charging polarity of the toner image formed on the photoreceptor 1a, in this example, a positive polarity. As a result, a transfer electric field is formed between the photosensitive member 1a and the intermediate transfer belt 10, and the toner image on the photosensitive member 1a is electrostatically applied to the intermediate transfer belt 10 that is rotationally driven in synchronization with the photosensitive member 1a. Is transcribed.

  In exactly the same manner, a magenta toner image, a cyan toner image, and a yellow toner image are respectively formed on the second to fourth photoreceptors 1b, 1c, and 1d, and the toner images of the respective colors are transferred to the black toner image. Electrostatic transfer is sequentially performed on the intermediate transfer belt 10 that has been applied.

  On the other hand, as shown in FIG. 1, a paper feeding device is disposed in the lower part of the apparatus main body. It is. The recording medium 25 sent out to the registration roller pair 27 that is not driven is a portion of the intermediate transfer belt 10 that is wound around the support roller 12 at a predetermined timing, and a secondary that is an example of a transfer device that is placed on the portion. The sheet is fed to the transfer roller 21 by driving the registration roller pair 27. At this time, a predetermined transfer voltage is applied to the secondary transfer roller 21, whereby the composite toner image on the intermediate transfer belt 10 is secondarily transferred to the recording medium 25.

  The recording medium 25 onto which the composite toner image has been secondarily transferred is further conveyed upward and passes through the fixing device 30. At this time, the toner image on the recording medium 25 is fixed by the action of heat and pressure. The recording medium 25 that has passed through the fixing device 30 is discharged out of the image forming apparatus via a pair of paper discharge rollers 32 provided in the paper discharge unit.

  Further, the transfer residual toner adhering to the intermediate transfer belt 10 after the toner image transfer is removed by a belt cleaning device 19 which is a cleaning device. In the belt cleaning device 19 in this embodiment, a blade-shaped cleaning blade 21 made of urethane or the like is used as a cleaning member, and the cleaning blade 21 is applied in the counter direction with respect to the rotation direction of the intermediate transfer belt 10. Touching. Instead of the cleaning blade 21, a conductive brush or roller may be used as a cleaning member so as to be electrostatically collected and removed. In particular, when the surface of the intermediate transfer belt 10 is cleaned using the cleaning blade 21 as a cleaning member as in this embodiment, if the adhesion is poor, contaminants such as toner slip through the intermediate transfer belt 10 and the intermediate Since there is a possibility that dirt on the transfer belt 10 may remain, in order to ensure adhesion between the cleaning member and the intermediate transfer belt 10, the cleaning member is a portion where the intermediate transfer belt 10 is wound around the support roller 13. It is preferable to install so as to cover the entire range facing the.

  The removed material, for example, transfer residual toner, removed by using such a cleaning member is transferred, for example, to the back side of the apparatus (backward in the vertical direction of the paper as viewed in FIG. 1) by a conveying member (not shown) in the cleaning apparatus 19. ), And is dropped downward by the action of gravity from the discharge port provided on the back side of the apparatus, and is also delivered directly to the inside of the removal object recovery bottle (not shown) via a connecting portion, or delivery of a hose or the like It can also comprise so that it can collect | recover indirectly via a part. When such a configuration is adopted, the removal object recovery bottle is provided with a means for detecting the amount of the removal object collected, and when the removal object is full, the apparatus is stopped to prevent the removal object from overflowing. It is preferable to do.

  Here, in the image forming apparatus as shown in FIG. 1, when it is intended to correct the deviation of the endless belt-like intermediate transfer belt 10 in the axial direction, it can be tilted as described in detail below. For example, providing the steering roller separately between the support rollers 12 and 13 is the easiest way to correct the belt deviation. On the other hand, since a certain amount of belt winding is required, when a separate steering roller as described above is provided between the support rollers 12 and 13, the steering roller is disposed above or below the support rollers 12 and 13. It is necessary to adopt a configuration in which the intermediate transfer belt 10 is strongly pressed against the steering roller. Therefore, in order to reduce the size of the apparatus as much as possible, a configuration is adopted in which the steering roller is brought into contact with the surface side of the intermediate transfer belt 10 and the steering roller is provided below the line connecting the support rollers 12 and 13. Since the transfer residual toner is transferred to the steering roller, there is a concern about contamination of the intermediate transfer belt 10 such as dirt, and such a configuration is not practical. Therefore, a steering roller is provided above the support rollers 12 and 13 so that the roller comes into contact with the back surface of the intermediate transfer belt 10. However, with such a configuration, not only the number of parts increases due to the provision of a separate steering roller, but the steering roller needs to be provided above the line connecting the support rollers 12, 13, This leads to an increase in the size of the image forming apparatus, which is very disadvantageous with respect to cost, leading to an increase in cost.

  Accordingly, in the present invention, the steering roller is not provided separately, but at least one of the conventionally used driven rollers is configured as a steering roller, and the driven roller has a plurality of functions. Yes.

  Next, a specific example of the belt deviation correcting device, which is a main component of the present invention, will be described with reference to FIGS. Here, in the image forming apparatus shown in FIG. 1, the intermediate transfer belt 10 is constituted by a wide endless belt, and in the belt deviation correcting apparatus according to the present invention, a support roller 13 (hereinafter referred to as a steering roller). The support roller 13 is also provided with a roller shaft displacement member 35 only on one side of the steering roller 13. Therefore, in FIG.2 and FIG.3, only the one side of the steering roller 13 is expanded and shown. In this embodiment, since the support roller 13 is configured as a steering roller, it is configured as a driven roller instead of a driving roller.

  In the belt deviation correction device shown in FIG. 2, it can be seen that the intermediate transfer belt 10 is wound around the roller shaft displacement member 35 in addition to the steering roller 13. Further, the steering roller 13 is disposed in a state where the axial direction is inclined downward from the horizontal direction indicated by the dotted line C as indicated by the alternate long and short dash line L. In this case, as described below, when the intermediate transfer belt 10 starts to travel from the upper side to the lower side as viewed in FIG. 2, the intermediate transfer belt 10 tries to move from the right side to the left side as viewed in FIG. It will be.

  The roller shaft displacing member 35 is wound around the endless belt-like intermediate transfer belt 10 in a state in which a flange portion 35 a provided at the end thereof is in contact with the inner end surface 10 a of the intermediate transfer belt 10. At this time, the steering roller 13 is provided with a roller shaft 13a. The roller shaft 13a penetrates not only the steering roller 13 but also the roller shaft displacement member 35 and cannot rotate to the roller shaft support member 40. It is fixed to. Therefore, even if the steering roller 13 and the roller shaft displacement member 35 start to rotate due to the rotation of the intermediate transfer belt 10, the roller shaft 13a does not rotate together. The roller shaft displacing member 35 must be disposed so as to be movable with respect to the axial direction of the roller shaft 13a as will be described below. Therefore, the roller shaft displacing member 35 is disposed at a certain distance from the steering roller 13. Between them, an elastic body 34 such as a pressing spring that presses the flange portion 35a of the roller shaft displacement member 35 against the end portion 10a of the intermediate transfer belt 10 is disposed (see FIGS. 2 and 3). In addition, although the elastic body 34 is comprised with the spring in a present Example, other various well-known elastic bodies can also be used suitably. Further, the roller shaft displacement member 35 has a part processed into a conical shape, and a guide 36 installed in a fixed position on the image forming apparatus main body or the like is provided in the conical portion with the weight of the steering roller 13 and the roller. The shaft displacement member 35 is in contact with its own weight.

Further, the roller shaft 13a, and hence the steering roller 13, is configured to be tiltable in the vertical direction as viewed in FIG. 2 with the other end of the roller shaft 13a not shown in FIG. 2 as a fulcrum. Moreover, the conical portion of the guide 36 and the roller shaft displacement member 37, but comes into contact by its own weight of the steering roller 13 own its own weight and the roller shaft displacing member 3 7, the roller shaft supporting the roller shaft 13a The support member 40 is provided with an auxiliary member 41 that is an elastic body such as a spring so as to support the roller shaft support member 40 in the vertical direction. The auxiliary member 41 is not limited to the spring as shown in the figure, and may be a leaf spring or the like. The auxiliary member 41 will be described later.

  Next, the operation of the belt deviation correcting device of the present invention will be described.

  First, in a state where the driving roller is not driven, as shown in FIG. 2, the belt deviation correcting device guides the conical portion of the roller shaft displacement member 37 by the weight of the steering roller 13 and the roller shaft displacement member 35. 36 is held in contact with 36. Even in this state, the pressing spring 34 presses the roller shaft displacement member 35 to the right in the drawing, so that the flange portion 35a of the roller shaft displacement member 35 is in contact with the belt end portion 10a of the intermediate transfer belt 10. Yes.

  Next, when the driving roller starts to rotate, the steering roller 13 as the driven roller also starts to rotate, but the roller shaft 13a does not rotate as described above. However, the roller shaft displacing member 35, which is wound around the end portion 10a of the intermediate transfer belt 10 while the flange portion 35a is in contact with the end portion 10a, rotates along with the rotation of the intermediate transfer belt 10 to the end portion 10a. Rotation is started in synchronism with the rotation of the intermediate transfer belt 10 while being in contact with each other. Here, when the intermediate transfer belt 10 starts to rotate, if the steering roller 13 is previously tilted downward from the horizontal line C as shown in FIG. The movement starts so as to approach the viewing direction.

  This principle will be described below with reference to FIG. For example, when the belt is driven from the top to the bottom of the roller while the belt is wound around the roller, assuming that the belt is a rigid body, paying attention to an arbitrary point on the belt before entering the roller If the belt wound around a plurality of rollers is in a completely horizontal or parallel state, the one point rotates on the roller without moving in the roller axial direction as the roller rotates. No movement occurs. On the other hand, as shown in FIG. 4, when one roller shaft is inclined by θ with respect to the other roller shaft, the one point on the belt is in the belt intrusion direction by sin θ as the roller rotates. On the other hand, it moves to the point moved to the left in the axial direction. As a result, it is possible to predetermine the direction of belt deviation by inclining the roller shaft in advance. Here, assuming that the diameter of the roller is D and the belt is stretched around a half circumference of the roller, in general, the deviation amount or the movement amount X of the belt due to the inclination of the roller is X = D X can be expressed as sin θ.

  2 and 3, when the intermediate transfer belt 10 moves to the left in the drawing as the intermediate transfer belt 10 is driven, the pressure spring 34 is compressed and the roller shaft displacement member 37 has a conical shape. As the part slides up the guide 36, the axis L of the roller shaft 13a of the steering roller 13 approaches the horizontal line C. In this case, the amount of the intermediate transfer belt 10 in the axial direction decreases due to a decrease in the above-described sin θ, and eventually the belt shift converges in a balanced state.

  The belt movement amount X described above is a physical change amount and is proportional to the inclination angle θ, or is proportional to the diameter of the roller around which the belt is wound or the winding amount of the belt. Therefore, in order to correct the belt shift with high sensitivity and efficiency with a small amount of tilt, the larger the roller diameter of the roller configured as a steering roller, or the longer the belt winding amount, the more advantageous It is.

  Therefore, it is preferable to select the support roller 13 which is a counter roller of the cleaning device 19 and has a large roller diameter and a long winding amount as a steering roller. By selecting the support roller 13 as the steering roller in this manner, the angle at which the roller shaft is tilted (steering angle) to correct the belt shift can be reduced, and the belt shift can be corrected efficiently. Therefore, space saving can be achieved, and as a result, the image forming apparatus can be reduced in size. In addition, since it is not necessary to tilt the steering roller 13 greatly, the space related to the belt can be reduced as much as possible, which is advantageous for arrangement of components of the image forming apparatus such as the steering roller 13 and the cleaning device 19.

  However, in such a configuration, the steering roller 13 is in contact with a cleaning blade 21 that is a cleaning member disposed in the cleaning device 19, and the cleaning blade 21 has a particle diameter on the intermediate transfer belt 10. Since it is necessary to dam the toner of several μm, if the steering roller 13 is inclined, the contact condition between the cleaning blade 21 and the intermediate transfer belt 10, for example, the contact position between the cleaning blade 21 and the intermediate transfer belt 10, etc. May change, and the intermediate transfer belt 10 may not be properly cleaned. Therefore, the present invention is configured such that the inclination of the cleaning device 19 can be integrally interlocked with the inclination of the steering roller 21.

An embodiment for Ru in conjunction with the inclination of the cleaning blade 21 and the inclination of the steering roller 13 will be described with reference to FIG. FIG. 5 corresponds to a top view of the steering roller 13 and the cleaning device 19 extracted from the image forming apparatus illustrated in FIG. 1 and viewed from above. In FIG. 5, the roller shaft displacement member 35 is omitted to facilitate understanding of the invention. However, in FIG. 5, the roller shaft displacement member is illustrated inside the casing of the steering roller 13 and the cleaning device 19. Between. Further, the steering roller 13 in FIG. 5 is configured to be tiltable in the direction perpendicular to the paper surface with the right end in FIG. 5 as a fulcrum.

  As shown in FIG. 5, a cleaning member support member 23 for supporting the cleaning blade 21 that is a cleaning member is provided, and the cleaning member support member 23 is fixed to the casing of the cleaning device 19. Here, since the roller shaft 13a of the steering roller 13 does not rotate with the rotation of the intermediate transfer belt 10, the roller shaft 13a can be connected to the casing of the cleaning device 19 and fixed. By configuring, the cleaning device 19 and thus the cleaning member 21 can be integrally tilted with respect to the tilt of the steering roller 13. Accordingly, the position of the cleaning device 19 is interlocked with the tilt of the steering roller 13, and as a result, the cleaning member 21 is positioned integrally with the steering roller 13 and operates in the same tilting direction. Even if the relationship does not change and the tilt of the steering roller 13 changes, the belt surface can be stably cleaned. Although not shown, the same effect can be obtained by forming the cleaning member support member 23 for supporting the cleaning member 19 in a substantially U shape and fixing both ends of the U shape to the roller shaft 13a of the steering roller 13. Can be obtained. In this case, it is not necessary to connect the cleaning device 19 to the roller shaft 13a.

  Here, in the present invention, since the cleaning device 19 is integrated with the steering roller 13, the weight applied to the roller shaft 13a greatly increases. As a result, a large shifting force is required to change the tilt of the steering roller 13. there is a possibility. In such a case, the steering roller 13 is held without moving even in a state where it acts on a belt such as the intermediate transfer belt 10 with a large shift force, and durability due to a high load on the belt is maintained. The problem is concerned. Therefore, by adding an auxiliary member 41 such as an auxiliary spring that supports the support member 40 that supports the roller shaft 13a from below, the steering roller 13 can be tilted even with a weak shifting force. Since the auxiliary member 41 is provided in this way, the tilt angle of the steering roller can be adjusted with a smaller force, so that the durability of the belt deviation correction device can be improved, and Further, various weight differences depending on the materials and configurations of the cleaning device 19 and the steering roller 13 and the degree of freedom in selecting the belt tension are increased, so that cost reduction can be achieved.

  Up to this point, the operation of the belt offset correction device has been described with reference to FIGS. 2 and 3, but the present invention is not limited to this embodiment. For example, the direction in which the steering roller 13 is inclined can be appropriately set according to the direction of rotation of the belt in consideration of which direction of the steering roller the belt is initially set toward. For example, as shown in FIG. 2, when the belt 10 travels from the upper side to the lower side in the drawing, the right end portion of the steering roller 13 may be installed downward as seen in FIG. In addition, when the belt 10 travels from the lower side to the upper side in the figure, a roller shaft displacement member is provided at the left end portion of the steering roller 13 (not shown in FIG. 2) so that the left side of the steering roller 13 is lowered. What is necessary is just to comprise. In this case, the right end of the steering roller 13 serves as a fulcrum for tilting the steering roller 13.

In addition, when the cleaning device 19 is provided with a discharge port to collect the removed material, for example, transfer residual toner, when the surface of the intermediate transfer belt 10 is cleaned by the cleaning device 19, it is provided at the same end of the steering roller 13. When the roller shaft displacing member and the discharge port are provided, the discharge port moves up and down as the steering roller 13 is tilted. Therefore, leakage of the removed matter occurs at the connection portion or the transfer portion between the discharge port and the removed matter collection bottle. Or, in order to prevent the leakage, the connecting portion or the like becomes large or complicated. This causes an increase in the size and cost of the apparatus, and the discharge port for discharging the removed matter from the cleaning device 19 is fixed to the roller shaft fulcrum side or fixed side opposite to the side where the roller shaft displacement member is provided. provided on the side Ru.

  Further, the steering roller 13 can have a function of applying tension to the intermediate transfer belt 10. In such a case, there is no need to provide a dedicated tension roller, which leads to further downsizing of the apparatus and reduction of the number of parts. Further, if the steering roller 13 is configured so as to be integrated with the cleaning device 19, it is convenient and effective when moving or operating as a tension roller.

  An example in which such a steering roller is also used as a tension roller will be described with reference to FIG. As shown in FIG. 6, the roller shaft 13a of the steering roller 13 receives the action of the tension spring 30 to press the intermediate transfer belt 10 outward, and the bracket 31 that holds the tension spring 30 rotates the bracket. It is supported so as to be rotatable about an axis. In the example shown in FIG. 6, since the center of the roller shaft 13a of the steering roller 13 is above the center of the bracket rotating shaft, the steering roller 13 itself receives an upward force under the tension of the intermediate transfer belt 10. It will be. Therefore, when the steering roller 13 is tilted downward in the direction shown in the drawing to correct the shift of the intermediate transfer belt 10, the steering roller 13 is tilted in the direction in which the steering roller 13 is lowered, that is, the tilt angle of the steering roller 13 is increased. What is necessary is just to provide the auxiliary member 41 which is elastic bodies, such as a spring, so that it may be made to change below. By providing such an auxiliary member 41, the tilt angle of the steering roller can be adjusted with a smaller force. Therefore, various weight differences depending on the material and configuration of the cleaning device 19 and the steering roller 13 are provided. The degree of freedom in selecting the belt tension and the belt tension can be increased, and the cost can be reduced.

  When the steering roller 13 also functions as a tension roller, the direction in which the steering roller 13 is given an inclination angle is set to the vertical direction as seen in FIG. 1 so as not to affect the tension on the belt 10 as much as possible. It is preferable to do this.

  As mentioned above, although preferable embodiment of this invention was described, this invention should not be limited only to the said embodiment. For example, in the above embodiment, the belt shift correction device for the intermediate transfer belt has been described. However, the present invention is not limited to the belt device using the intermediate transfer belt, but a belt device using a transfer material conveyance belt, a belt device using a fixing belt, or The present invention can also be applied to prevention of belt deviation of a belt device using a photosensitive belt.

1 is a diagram schematically showing a tandem indirect (intermediate) transfer type electrophotographic apparatus to which a belt deviation correcting device of the present invention is applied. FIG. It is a side view which shows roughly an example of the belt deviation correction apparatus of this invention. It is a perspective view which shows roughly an example of the belt deviation correction apparatus of this invention. It is explanatory drawing for demonstrating the belt side. It is a top view which shows roughly one Example for making the inclination of a cleaning blade interlock | cooperate with the inclination of a steering roller. It is a side view which shows roughly the Example of this invention which makes a steering roller also use the function of a tension roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Belt 10a Belt end part 13 Steering roller 13a Steering roller shaft 19 Cleaning device 21 Cleaning member (cleaning blade)
35 Roller shaft displacement member 35a Collar part 34 Elastic body (positioning spring)
36 Guide 41 Auxiliary member (Auxiliary spring)

Claims (8)

A belt deviation correction device that has an endless belt that is wound around a plurality of rollers and driven to travel, and corrects the belt deviation of the endless belt,
At least one of the plurality of rollers is configured as a tiltable steering roller,
The steering roller is configured to tilt in advance in one direction when the endless belt travels by inclining a roller shaft of the steering roller in advance.
At one end of the steering roller, a roller shaft displacement member capable of changing the tilt angle of the roller by displacing the one end side with the other end side of the steering roller as a fulcrum according to the shift amount of the endless belt Is provided,
In the belt deviation correction device in which the roller shaft displacement member tilts the steering roller at an angle that balances the inclination of the steering roller due to the deviation of the endless belt,
The steering roller is a roller facing a cleaning member that cleans the surface of the belt,
The cleaning member for cleaning the surface of the endless belt is inclined integrally with the steering roller in accordance with the inclination of the steering roller; and
A cleaning device in which the cleaning member is disposed is further provided;
The cleaning device has a discharge port for discharging the removed material when the cleaning member cleans the belt surface to the outside of the cleaning device , and the discharge port is provided on the other end side.
The belt shift correcting device, wherein the roller shaft displacement member is provided on the one end side.   2. The belt shift correction according to claim 1, wherein the steering roller is a roller having a longest belt winding amount among driven rollers excluding a driving roller that drives the endless belt in the plurality of rollers. apparatus. The steering roller includes a support member that supports the one end,
When changing the inclination angle of the steering roller according to the endless belt, the auxiliary member assists the change in the inclination angle of the steering roller by urging the support member to displace the one end side. The belt misalignment correction apparatus according to claim 1, wherein the belt misalignment correction apparatus is provided. In the belt device using the belt deviation correcting device according to any one of claims 1 to 3,
A belt device, wherein the belt is a photosensitive belt used in an image forming apparatus. In the belt device using the belt deviation correcting device according to any one of claims 1 to 3,
A belt device, wherein the belt is an intermediate transfer belt used in an image forming apparatus. In the belt device using the belt deviation correcting device according to any one of claims 1 to 3,
A belt device, wherein the belt is a transfer material conveyance belt used in an image forming apparatus. In the belt device using the belt deviation correcting device according to any one of claims 1 to 3,
A belt device, wherein the belt is a fixing belt used in an image forming apparatus.   An image forming apparatus comprising the belt device according to claim 4.

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