JP2008107644A - Automatic meandering correction mechanism and image forming apparatus with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic meandering adjustment mechanism which can correct the meandering of an endless belt by simple and compact configuration and is excellent in the durability of the belt and to provide an image forming apparatus with the same. <P>SOLUTION: A first correction roller 20a and a second correction roller 20b constituting a pair of correction rollers 20 are in parallel to each other, the first correction roller 20a abuts on the inner circumferential surface side of an intermediate transfer belt 8 and the second correction roller 20b abuts on the outer circumferential surface side of the intermediate transfer belt 8 in the contact position of the first correction roller 20a. When the meandering of the intermediate transfer belt 8 is detected by a meandering detection sensor 21, a detection signal is transmitted to a control section and the meandering direction and meandering amount of the belt are calculated in the control section. The pair of correction rollers 20 are rocked toward both sides of the belt, in such a state that the first correction roller 20a and the second correction roller 20b are held in a parallel state, in accordance with the meandering direction and the meandering amount, so that the intermediate transfer belt 8 held by the pair of correction rollers 20 is inclined by a predetermined angle to correct the meandering. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a meandering correction mechanism for rotationally driving an endless belt such as a conveyance belt or an intermediate transfer belt, and an image forming apparatus including the same.

  Conventionally, various image forming apparatuses have been proposed. The image forming apparatus includes an endless conveying belt that rotates in a predetermined direction, and an image forming unit that is provided along the conveying belt. An image forming apparatus that transfers a toner image formed by an image forming unit onto a recording medium that is conveyed, or a toner image that is sequentially superimposed on an endless intermediate transfer belt by a plurality of image forming units, There is an intermediate transfer type image forming apparatus that transfers onto a recording medium at once.

  In the image forming apparatus using the endless conveyance belt as described above, the conveyance belt meanders due to misalignment of the suspension roller such as the driving roller or the tension roller due to distortion of the apparatus main body, so-called misalignment. There was a case. When the conveyance belt meanders, the position of the sheet to be conveyed is shifted to the left and right, and the transfer image is likely to be displaced.

  Further, in the case of a tandem color image forming apparatus that forms one image by a plurality of image forming units, the alignment of each color image formed in each image forming unit deteriorates due to the meandering of the conveyor belt, and each color toner Image color misregistration is likely to occur. In the intermediate transfer type image forming apparatus, the same problem occurs due to the meandering of the intermediate transfer belt.

  A conventional endless belt meandering correction mechanism is shown in FIG. In addition, the arrow in a figure has shown the belt drive direction, and the endless belt 101 has described only the edge part with the continuous line for convenience of explanation. Conventionally, as shown in FIG. 8, the endless belt 101 is stretched between a tension roller 102 and a driving roller 103, and one correction roller 104 is disposed on the inner peripheral surface side of the endless belt 101. A method of automatically correcting meandering by adjusting the angle of the correction roller 104 in the front and back direction of the belt according to the meandering amount is performed.

  However, since the endless belt 101 needs to be wound around the correction roller 104 to some extent even when the angle adjustment amount of the correction roller 104 is maximized as shown in FIG. 9, the belt winding angle θ around the correction roller 104 is sufficient in advance. It was necessary to secure it. Therefore, as shown in FIGS. 8 and 9, the endless belt 101 protrudes in a mountain shape at the position where the correction roller 104 is disposed, and the increase in the space for arranging the correction roller 104 reduces the size and space of the image forming apparatus. It was a hindrance.

  The tension roller 102 has a pressure mechanism (not shown) at both ends of the roller in order to apply a predetermined tension to the endless belt 101, but the right and left sides of the correction roller 104 can be adjusted by adjusting the angle of the correction roller 104. When the belt winding angle changes at the end portions 104a and 104b, the parallelism between the tension roller 102 and the other suspension rollers (here, the drive roller 103 and the correction roller 104) is lost on the left and right sides of the belt as shown in FIG. The belt tension due to the pressure mechanism changes on the left and right sides of the belt, and consequently the belt circumferential length changes.

  For example, in the case of a tandem type color image forming apparatus, color misregistration (registration misregistration) of each color occurs due to the difference between the peripheral lengths of the belt on the left and right sides. It will cause image distortion.

  Therefore, various methods for preventing meandering while suppressing a change in the tension of the belt have been proposed. For example, Patent Document 1 discloses the trajectory of the roller central axis when adjusting the correction roller as the upstream side and the downstream side of the correction roller. A method for preventing a change in belt tension is disclosed as an elliptical orbit having a central axis of the side roller as a focal point. In Patent Document 2, the correction roller is composed of two parallel rollers having a predetermined interval, and a belt is applied to the two rollers to change the belt winding angle on the left and right sides of the correction roller. A method of suppressing this is disclosed.

  However, the method of Patent Document 1 has a problem that the adjustment track of the correction roller needs to be strictly defined in order to prevent a change in belt tension, and the assembly process becomes complicated. In addition, the method of Patent Document 2 has a problem in that the belt is wound around the two correction rollers by a predetermined amount, so that friction between the correction roller and the belt surface increases and wear of the belt surface becomes remarkable. It was.

JP-A-5-301651 Japanese Patent Application Laid-Open No. 11-59999

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an automatic meander adjustment mechanism that can prevent meandering of an endless belt with a simple and compact configuration, and is excellent in belt durability, and an image forming apparatus including the same. With the goal.

  To achieve the above object, the present invention provides an endless belt, a plurality of suspension rollers including a tension roller that applies a predetermined tension to the endless belt, and a driving roller that applies a rotational driving force to the endless belt, An automatic meandering correction mechanism comprising meandering detection means for detecting meandering of an endless belt and correction means for correcting meandering of the endless belt based on a detection result of the meandering detection means. A correction roller pair comprising a first correction roller that contacts the inner peripheral surface of the belt and a second correction roller that is parallel to the first correction roller and contacts the outer peripheral surface of the contact position of the first correction roller; The angle adjusting means adjusts the inclination of the correction roller pair in the belt front-back direction while maintaining the parallel state of the first and second correction rollers.

  According to the present invention, in the automatic meandering correction mechanism configured as described above, the correction roller pair is supported so as to be swingable about a central portion in the longitudinal direction.

  The present invention is also an image forming apparatus provided with the automatic meandering correction mechanism having the above-described configuration, wherein the endless belt is a conveyance belt for conveying a recording medium.

  Further, the present invention is an image forming apparatus provided with the automatic meandering correction mechanism having the above-described configuration, wherein the endless belt is an intermediate transfer belt on which toner images for transfer onto a recording medium are sequentially stacked. Yes.

  According to the first configuration of the present invention, it is not necessary to project the endless belt into a mountain shape and wind the belt around the correction roller in advance, and the space for arranging the correction roller can be reduced. When the inclination of the correction roller pair is not adjusted, the first correction roller and the second correction roller are in line contact with the inner peripheral surface and the outer peripheral surface of the endless belt, so that the contact area between each correction roller and the belt surface And the wear of the endless belt can be suppressed.

  Further, according to the second configuration of the present invention, in the automatic meandering correction mechanism of the first configuration, the center portion in the longitudinal direction of the correction roller pair is swingably supported, so that the endless belt can be adjusted during meandering correction. The belt tension is equalized in the width direction, and the parallel relationship between the tension roller and the other suspension roller is maintained.

  In addition, according to the third configuration of the present invention, by mounting the automatic meandering correction mechanism of the first or second configuration, space saving, low maintenance cost, and suppression of registration deviation on the left and right sides of the belt can be suppressed. Image forming apparatus. Further, by correcting the meandering of the conveying belt for conveying the recording medium, it is possible to prevent registration deviation when the toner image formed in the image forming unit is transferred to the recording medium, particularly in a color image forming apparatus. The color registration accuracy of each color toner image can be ensured to prevent color misregistration.

  Further, according to the fourth configuration of the present invention, by mounting the automatic meandering correction mechanism of the first or second configuration, space saving, low maintenance cost, and suppression of registration deviation on the left and right sides of the belt can be suppressed. Image forming apparatus. In addition, by correcting meandering of an intermediate transfer belt on which toner images for transfer onto a recording medium are sequentially stacked, toner images of each color are sequentially stacked on the intermediate transfer belt to form a color image, and then on the transfer paper. A similar color misregistration preventing effect can be obtained even in an image forming apparatus that transfers at a time, and an image distortion preventing effect on the left and right sides of the belt can also be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus according to a first embodiment provided with an automatic meandering correction mechanism of the present invention. In this embodiment, the automatic meandering correction mechanism is used for meandering correction of the intermediate transfer belt of the tandem type color image forming apparatus. First, the image forming process of the tandem type color image forming apparatus will be described with reference to FIG.

  In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  Photosensitive drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of the respective colors are disposed in the image forming portions Pa to Pd, and are formed on the photosensitive drums 1a to 1d. The transferred toner image is rotated clockwise in FIG. 1 by a driving means (not shown), and sequentially transferred onto the intermediate transfer belt 8 that moves adjacent to each image forming unit, and then transferred by the transfer roller 9. The image is transferred onto the paper P at a time, and further fixed on the transfer paper P in the fixing unit 7 and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d counterclockwise in FIG.

  The transfer paper P onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the apparatus, and is conveyed to the transfer roller 9 via the paper supply roller 12a and the registration roller 12b. A sheet made of a dielectric resin is used for the intermediate transfer belt 8, and a belt in which both ends thereof are overlapped and joined to form an endless shape, or a belt without a seam (seamless) is used.

  Next, the image forming units Pa to Pd will be described. There are chargers 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d and image information on the photosensitive drums 1a to 1d around and below the photosensitive drums 1a to 1d that are rotatably arranged. The exposure unit 4 for exposing the toner, the developing units 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning units 5a, 5b, 5c and 5d are provided.

  When the image formation start is input by the user, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, and then light is irradiated by the exposure unit 4 to each of the photosensitive drums 1a to 1d. An electrostatic latent image corresponding to the image signal is formed on the top. Each of the developing units 3a to 3d is filled with a predetermined amount of cyan, magenta, yellow, and black toner by a replenishing device (not shown). The toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached, whereby a toner image corresponding to the electrostatic latent image formed by exposure from the exposure unit 4 is formed. It is formed.

  After an electric field is applied to the intermediate transfer belt 8 at a predetermined transfer voltage, cyan, magenta, yellow, and black toner images on the photosensitive drums 1a to 1d are transferred to the intermediate transfer belt 8 by the intermediate transfer rollers 6a to 6d. Transcribed above. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning units 5a to 5d in preparation for the subsequent formation of a new electrostatic latent image.

  The intermediate transfer belt 8 is stretched between an upstream tension roller 10 and a downstream drive roller 11, and the intermediate transfer belt 8 rotates clockwise as the drive roller 11 is rotated by a drive motor (not shown). When the rotation is started, the transfer paper P is conveyed from the registration roller 12b to a transfer roller 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and a full color image is transferred. The transfer paper P onto which the toner image is transferred is conveyed to the fixing unit 7.

  Further, a cleaning blade 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed on the downstream side of the transfer roller 9, and on the further downstream side of the cleaning blade 19, the first is in contact with the inner peripheral surface side of the belt. A correction roller pair 20 including a correction roller 20a and a second correction roller 20b that contacts the outer peripheral surface side, and a meandering detection sensor 21 that detects meandering of the intermediate transfer belt 8 are disposed.

  The transfer paper P conveyed to the fixing unit 7 is heated and pressurized by the fixing roller pair 13 so that the toner image is fixed on the surface of the transfer paper P, and a predetermined full color image is formed. The transfer paper P on which the full-color image is formed is distributed in the transport direction by the branching portion 14 that branches in a plurality of directions. When an image is formed only on one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller 15.

  On the other hand, when images are formed on both sides of the transfer paper P, a part of the transfer paper P that has passed through the fixing unit 7 is once protruded from the discharge roller 15 to the outside of the apparatus. Thereafter, the transfer paper P is distributed to the paper transport path 18 by the branching portion 14 by rotating the discharge roller 15 in the reverse direction, and is transported again to the transfer roller 9 with the image surface reversed. Then, the next image formed on the intermediate transfer belt 8 is transferred to the surface of the transfer paper P on which the image is not formed by the transfer roller 9 and conveyed to the fixing unit 7 to fix the toner image, and then discharged. It is discharged to the tray 17.

  2 and 3 are a schematic perspective view and a side view showing a configuration around the intermediate transfer belt of the image forming apparatus shown in FIG. Portions common to FIG. 1 are denoted by the same reference numerals and description thereof is omitted. 8 to 10 of the conventional example, the arrow in the drawing indicates the belt driving direction, the intermediate transfer belt 8 has only the edge portion indicated by a solid line, and the image forming portions Pa to Pd are not shown. is doing. 2 and 3, the first correction roller 20a and the second correction roller 20b constituting the correction roller pair 20 are parallel to each other, and the first correction roller 20a is disposed on the inner peripheral surface side of the intermediate transfer belt 8. The second correction roller 20b is in contact with the outer peripheral surface side of the contact position of the first correction roller 20a.

  The meandering detection sensor 21 is arranged so that the edge portion of the intermediate transfer belt 8 is sandwiched from the front and back by a U-shaped detection portion 21a provided with a light emitting portion and a light receiving portion (not shown). The position of the edge portion is detected by the position where the edge portion blocks the light path from the light emitting portion to the light receiving portion of the detecting portion 21a, and the meandering direction and the amount of meandering of the intermediate transfer belt 8 can be detected.

  4 is a front view of the correction roller pair 20 as viewed from the right direction in FIG. 3, and FIG. 5 is a left side view of FIG. A meandering adjustment mechanism of the intermediate transfer belt 8 will be described with reference to FIGS. 4 and 5. The rotation shaft 23a of the first correction roller 20a and the rotation shaft 23b of the second correction roller 20b are rotatably supported by a U-shaped support frame 25. The support frame 25 is supported by the main body frame 30 at a fulcrum 27 provided at the center in the longitudinal direction so as to be swingable in the direction of arrow AA ′.

  A rack 31 with rack teeth in the vertical direction is fixed to one side surface (left side in FIG. 4) of the support frame 25, and a gear 33 is disposed at a position where the rack 31 meshes with the rack 31. The gear 33 is connected to an angle adjusting motor (not shown) directly or through another gear train. Since the support frame 25 swings about the fulcrum 27, the rack 31 also moves on an arc centered on the fulcrum 27. Therefore, in order to smoothly mesh the rack 31 and the gear 33, each rack tooth 31a is carved at a predetermined angle so as to be horizontal at the meshing position with the gear 33.

  When the meandering sensor 21 detects meandering of the intermediate transfer belt 8, a detection signal is transmitted to a control unit (not shown), and the control unit calculates the meandering direction and the meandering amount of the belt. Then, a control signal is transmitted from the control unit to the angle adjusting motor, and the gear 33 is rotated in a predetermined direction by a predetermined amount. As a result, the rack 31 moves upward or downward, and the support frame 25 to which the rack 31 is fixed swings about a fulcrum 27 by a predetermined angle in the arrow A or A ′ direction. Accordingly, since the correction roller pair 20 also swings with the support frame 25 while maintaining the parallel state, the meandering can be corrected by inclining the intermediate transfer belt 8 sandwiched between the correction roller pair 20 by a predetermined angle.

  For example, when the intermediate transfer belt 8 is meandering in the right direction (right direction in FIG. 4) when viewed from the traveling direction, the gear 33 is rotated counterclockwise in FIG. 5, and as shown in FIG. When the left end 40 is lowered by a predetermined amount as viewed from the traveling direction of the pair 20, the right end 41 is elevated by a predetermined amount as viewed from the traveling direction of the correction roller pair 20. As a result, the intermediate transfer belt 8 is inclined upward to the right when viewed from the traveling direction, so that it gradually shifts to the left as it rotates, and the meandering to the right is corrected. Further, when the intermediate transfer belt 8 meanders in the left direction (left direction in FIG. 4) as viewed from the traveling direction, the gear 33 is rotated in the reverse direction (clockwise in FIG. 5) to move the left end 40 to a predetermined amount. The intermediate transfer belt 8 may be inclined upward as viewed from the traveling direction.

  In the present embodiment, the pair of parallel first correction roller 20a and the second correction roller 20b sandwiching the intermediate transfer belt 8 constitutes the correction roller pair 20, so that the intermediate transfer is performed when the correction roller pair 20 is tilted. The belt 8 is wound around either the first correction roller 20a or the second correction roller 20b. This eliminates the need to project the intermediate transfer belt 8 in a mountain shape and wind the belt around the correction roller in advance, thereby contributing to space saving and compactness of the image forming apparatus.

  When the correction roller pair 20 is not tilted, the first correction roller 20a and the second correction roller 20b are in line contact with the inner peripheral surface and the outer peripheral surface of the intermediate transfer belt 8, so that the correction roller and the belt are compared with the conventional one. The contact area with the surface is reduced. Therefore, wear on the surface of the intermediate transfer belt 8 is suppressed, durability is improved, and maintenance costs are reduced.

  The fulcrum 27 that supports the correction roller pair 20 can be provided, for example, at the left end or the right end of the correction roller pair 20, but the correction roller pair 20 is used as a fulcrum at the center in the longitudinal direction as in the above embodiment. By supporting the belt, the belt tension is equalized in the width direction of the intermediate transfer belt 8. Therefore, the parallel relationship between the tension roller 10 and the other suspension roller is maintained, and color misregistration (registration misregistration) on the left and right sides of the belt does not occur. Therefore, the position where the fulcrum 27 is provided is preferably the central portion in the longitudinal direction of the support frame 25.

  FIG. 7 is a schematic diagram showing a configuration of an image forming apparatus according to the second embodiment provided with the automatic meandering correction mechanism of the present invention. In the present embodiment, in a tandem type color image forming apparatus of a type that directly transfers an image of each color onto a sheet P, the sheet P is moved to the inner peripheral surface side of the conveying belt 35 that sequentially conveys the sheet P to the image forming units Pa to Pb. The first correction roller 20a is arranged, and the second correction roller 20b is arranged on the outer peripheral surface side of the contact position of the first correction roller 20a. Since the meandering detection method and meandering correction method are exactly the same as those in the first embodiment, description thereof will be omitted.

  Also in this embodiment, it is not necessary to wind a belt around the correction roller in advance as in the first embodiment, which contributes to space saving and compactness of the image forming apparatus. Further, since the first and second correction rollers 20a and 20b are in line contact with the surface of the conveying belt 35, wear of the intermediate transfer belt 8 is also suppressed. Further, since the belt tension is equalized in the width direction of the conveyor belt 35, there is no possibility of color misregistration (registration misregistration) of each color.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, an optical sensor including a light emitting unit and a light receiving unit is used as a meandering detection sensor. For example, another sensor such as a reflective sensor that emits light to the belt surface and measures reflected light is used. It may be used. Moreover, you may give the marking for detecting a meandering on the belt surface.

  Further, the lengths and the roller diameters of the first correction roller 20a and the second correction roller 20b may be appropriately set according to the width of the endless belt and the belt length. Further, the drive mechanism of the correction roller pair 20 is not limited to the combination of the rack 31 and the gear 33. For example, the end of the support frame 25 may be moved up and down using an eccentric cam and a motor.

  The present invention is not limited to the tandem type color image forming apparatus as in the above-described embodiment, but can be applied to various image forming apparatuses using a conveyance belt and an intermediate transfer belt, such as a monochrome copying machine, a digital multifunction machine, a facsimile machine, and a laser printer. Applicable.

  The present invention relates to an endless belt, a plurality of suspension rollers including a tension roller that applies a predetermined tension to the endless belt, and a driving roller that applies a rotational driving force to the endless belt, and a meander detection that detects meandering of the endless belt. And a correcting means for correcting the meandering of the endless belt based on the detection result of the meandering detecting means, wherein the correcting means is a first correction roller that abuts on the inner peripheral surface of the endless belt. A correction roller pair that is parallel to the first correction roller and is in contact with the outer peripheral surface of the contact position of the first correction roller, and the parallel state of the first and second correction rollers is maintained. The angle adjusting means for adjusting the inclination of the correction roller pair in the belt front and back direction is used.

  As a result, there is no need to keep the endless belt protruding in the shape of a mountain, and when the meandering correction is not performed, the correction roller and the belt surface are in line contact with each other. A correction mechanism can be provided. Also, if the correction roller pair is supported at the center in the longitudinal direction, the belt tension is equalized on the left and right sides of the belt during meander correction, and the suspension roller can be maintained in a parallel state.

  In addition, by mounting the automatic meandering correction mechanism of the present invention, the image forming apparatus can save space, have a low maintenance cost, and can suppress registration deviation between the left and right sides of the belt. In particular, when used for meandering correction of a conveyance belt or an intermediate transfer belt of a color image forming apparatus, it is possible to provide an image forming apparatus that forms a high-quality image by preventing color misregistration of each color toner image.

These are schematic diagrams showing the configuration of the image forming apparatus of the first embodiment provided with the automatic meandering adjustment mechanism of the present invention. FIG. 2 is a schematic perspective view showing a configuration around an intermediate transfer belt in the image forming apparatus of the first embodiment. FIG. 2 is a schematic side view showing a configuration around an intermediate transfer belt in the image forming apparatus of the first embodiment. These are the front views which looked at the correction | amendment roller pair from the right direction of FIG. These are the side views which looked at the correction roller pair from the left direction of FIG. FIG. 5 is a schematic perspective view showing a state in which the meandering of the intermediate transfer belt is corrected by tilting the correction roller pair. These are the schematic diagrams which show the structure of the image forming apparatus of 2nd Embodiment provided with the automatic meandering adjustment mechanism of this invention. These are the schematic perspective views which show the meandering correction mechanism of the conventional endless belt. These are the schematic perspective views which show the case where a correction roller is inclined in the conventional meandering correction mechanism. These are the schematic plan views which show the state of the tension roller when the correction roller is inclined in the conventional meandering correction mechanism.

Explanation of symbols

Pa to Pd Image forming section 8 Intermediate transfer belt (endless belt)
10 Tension roller 11 Drive roller 20 Correction roller pair (correction means)
20a 1st correction roller 20b 2nd correction roller 21 Meander detection sensor (meander detection means)
25 support frame 27 fulcrum 31 rack (angle adjusting means)
33 Gear (Angle adjustment means)
35 Conveyor belt (endless belt)
100 Image forming apparatus

Claims (4)

A plurality of suspension rollers including: an endless belt; a tension roller that applies a predetermined tension to the endless belt; and a driving roller that applies a rotational driving force to the endless belt;
Meander detection means for detecting meandering of the endless belt;
In an automatic meandering correction mechanism comprising correction means for correcting meandering of the endless belt based on the detection result of the meandering detection means,
The correction means includes a first correction roller that contacts the inner peripheral surface of the endless belt, and a second correction roller that is parallel to the first correction roller and contacts the outer peripheral surface side of the contact position of the first correction roller. And an angle adjusting means for adjusting the inclination of the correction roller pair in the belt front-back direction while maintaining the parallel state of the first and second correction rollers. Meander correction mechanism.   The automatic meandering correction mechanism according to claim 1, wherein the correction roller pair is supported so as to be swingable about a central portion in a longitudinal direction.   3. An image forming apparatus comprising the automatic meandering correction mechanism according to claim 1 or 2, wherein the endless belt is a transport belt for transporting a recording medium.   3. The image forming apparatus having the automatic meandering correction mechanism according to claim 1 or 2, wherein the endless belt is an intermediate transfer belt on which toner images for transfer onto a recording medium are sequentially stacked. An image forming apparatus.

Images