JP2002148882A - Belt conveying device and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and accurately perform driving and control of steering at low cost while keeping replacement operability excellent in a style wherein a device is equipped with a steering drive roll. SOLUTION: This belt conveying device which has an endless belt 2 trained around a roll group 1 including the steering drive roll 1a is equipped with a driving transmission member 4 which is coupled with a driving source 3 arranged on the installation main body side of the belt conveying device and has meshing teeth 4a formed, a driven transmission member 5 which is provided in the steering drive roll 1a and has meshing teeth 5a capable of engaging the meshing teeth 4a of the driving transmission member 4, and a slanting track restricting means 6 which restricts the slanting track (m) of the steering drive roll 1 so that the center position O4 of the driving transmission member 4 is positioned within the range of the pressure angle αof the meshing teeth 5a from the center position O5 of the driven transmission member 5. Further, an image forming device in which this belt conveying device is incorporated is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt conveying device for circulating and rotating an endless belt, and more particularly, to a plurality of roll groups including a steering drive roll that is tiltably driven to enable meandering adjustment. The present invention relates to a belt transport device in which an endless belt is stretched and an improvement of an image forming apparatus using the belt transport device.

[0002]

2. Description of the Related Art Conventionally, this type of belt conveying apparatus is used in, for example, a tandem type image forming apparatus. This type of tandem type image forming apparatus is, for example, yellow, magenta,
An image forming unit that forms each color component image of cyan and black, and a belt conveying device that circulates and conveys an intermediate transfer or recording material conveying belt toward an image transfer portion of the image forming unit; Each color component image formed by the forming unit is multiplex-transferred to a recording material via a belt or directly. By the way, this type of belt conveying device usually stretches a belt around a plurality of roll groups including a driving roll, but due to a parallelism error of each roll, the belt is moved in a lateral direction orthogonal to a running direction. There is a concern that a meandering, so-called belt walk phenomenon may occur.

[0003] Such a belt walk phenomenon leads to a cause of color misregistration of each color component image. Therefore, in order to maintain good color image quality, it is necessary to control this kind of belt walk phenomenon. Conventionally, an active steering system in which one of the belt tension rolls is a tiltable steering roll, and the steering roll is tilted according to the state of the belt walk to control the meandering of the belt in the lateral direction is usually adopted. (See, for example, JP-A-9-197907). Also,
From the viewpoint of reducing the thickness of the entire belt conveying device, a type in which a steering roll is used as a steering drive roll that also serves as a drive roll has already been provided (see, for example, Japanese Patent Application Laid-Open No. H5-24704).

[0004]

By the way, in a belt conveying device provided with a steering drive roll, for example, one shaft end of the steering drive roll and a drive motor are supported by a support member, and the support member is interposed therebetween. A configuration is adopted in which the steering drive roll is tilted.
In this aspect, there is an advantage that the drive transmission during the tilting of the steering drive roll is facilitated. However, in the case of this type of belt transport device, when the belt transport device is applied to a belt that requires regular replacement, a unit that can replace the belt transport device (Customer Replaceable Unit)
However, in this embodiment, the unit itself has a drive motor, so that the configuration inside the unit becomes complicated and the cost increases, and the weight of the unit is reduced. There is a technical problem that the replacement operability of the unit is impaired by the weight.

In order to solve such technical problems, a drive motor is installed on the installation body side where the belt transport device is installed, and a drive transmission system such as a gear is provided between the drive motor and the steering drive roll. A method is conceivable in which a driving gear and a driven gear are interposed, a driving force is transmitted to a steering driving roll, and the belt conveying device is unitized separately from the driving motor.
However, in this type of belt conveyance device, when a drive transmission system such as a gear is used, when the steering drive roll is tilted, the drive gear on the drive motor side and the driven gear on the steering drive roll side are driven. A new technical problem has been found in that the meshing state changes, and the driven gear is displaced in the rotation direction in accordance with the change, so that an angular velocity error easily occurs in the belt.

[0006] Such technical problems are not limited to the belt transport device used in the tandem type image forming apparatus, but include various belt transport devices including a belt transport device such as a photosensitive belt. Also occurs in the same manner. SUMMARY OF THE INVENTION The present invention has been made to solve the above technical problem, and in an aspect including a steering drive roll, driving and meandering are performed stably and accurately while maintaining good replacement operability at low cost. An object of the present invention is to provide a belt transport device capable of performing control and an image forming apparatus using the same.

[0007]

That is, according to the present invention, as shown in FIGS. 1 (a) to 1 (c), a plurality of steering driving rolls 1a which are tiltably driven to enable meandering adjustment are included. In a belt transport device in which the roll groups 1 (for example, 1a to 1e) are arranged in parallel and the endless belt 2 is wound around these roll groups 1, a driving source disposed on the installation main body side where the belt transport device is installed A drive transmission member 4 which is drivably connected to 3 and has meshing teeth 4a formed thereon;
A driven transmission member 5 provided on the steering drive roll 1a and having teeth 5a capable of meshing with the meshing teeth 4a of the drive transmission member 4; and a driven transmission member with respect to the tilt locus m of the steering drive roll 1. 5 so that the center position O4 of the drive transmitting member 4 is located within the range of the pressure angle α of the meshing teeth 5a from the center position O5 of the steering drive roll 1.
And a tilt locus restricting means 6 for restricting the tilt locus m. In FIG. 1A, the other rolls 1b to 1e are usually used as driven rolls, and can have required functions as required. For example, the rolls 1b and 1c are like surfaced rolls that regulate the position of the endless belt 2, and the roll 1d is like a tension roll that applies tension to the endless belt 2.

In such technical means, the drive transmission member 4 and the driven transmission member 5 widely include gears as long as they have the meshing teeth 4a, 5a. The drive transmission member 4 may be connected to the drive source 3 on the installation main body side, and the center position of the drive transmission member 4 is basically fixed, but may be movable. Further, the tilting locus restricting means 6
As long as the drive transmission member 5 is hardly displaced in the rotational direction due to a change in the meshing state of the drive transmission member 4 and the driven transmission member 5 during the tilting operation of the steering drive roll 1a, it is sufficient.

As shown in FIG. 1 (c), the pressure angle α at the pitch point (intersection point between the tooth profile curve and the pitch circle) of the tooth surface of the meshing tooth 5a of the driven transmission member 5 has the radius It means the angle between the line r and the tangent s to the tooth profile of the meshing teeth 5a. Further, the tilt locus m of the steering drive roll 1a
The reason why the pressure angle α range is selected as the allowable range is that even if the center position O4 of the drive transmission member 4 is shifted from the tilt locus m by the maximum pressure angle α range, the rotational displacement to the driven transmission member 5 Due to little effect.

Further, from the viewpoint of smoothly performing the tilting operation and the driving operation of the steering drive roll 1, the tilt trajectory restricting means 6 controls the steering while maintaining the meshing state of the drive transmission member 4 and the driven transmission member 5. It is preferable to regulate the tilt locus m of the driving roll 1a. If the drive transmission member 4 and the driven transmission member 5 are disengaged from each other, the meshing teeth 4
a and 5a may interfere with each other, which is not preferable.

From the viewpoint of optimizing the position of the tilt fulcrum 7 of the steering drive roll 1a, the tilt trajectory restricting means 6 sets the tilt fulcrum 7 of the steering drive roll 1a in the axial direction of the steering drive roll 1a. It is preferable that the drive transmission member 4 and the driven transmission member 5 are disposed close to the meshing position. According to this aspect, it is possible to minimize the change in the position of the rotation drive transmission unit when the steering drive roll 1a is tilted, and to minimize the backlash change of the meshing teeth 4a, 5a in the rotation drive transmission unit. The tilting fulcrum 7 here means a fulcrum for tilting the steering drive roll 1a, and is usually set at a predetermined fixed position.

Further, the tilt locus m of the steering drive roll 1a may be appropriately selected as long as it is within the above-described allowable range. From the viewpoint of optimizing the tilt locus m of the steering drive roll 1a, The tilt trajectory restricting means 6 includes the drive transmission member 4 and the driven transmission member 5.
It is preferable to regulate the tilt locus m of the steering drive roll 1a along the direction of the pressure angle α at the meshing portion of the steering drive roll 1a. According to this aspect, when the steering drive roll 1a is tilted, the meshing portion of the drive transmission member 4 and the driven transmission member 5 relatively moves, but the meshing teeth 4a, 5a relatively move in the pressure angle α direction. This has no effect on the rotational displacement to the driven transmission member 5, and the angular velocity error of the steering drive roll 1a via the driven transmission member 5 becomes very small.

Further, the present invention is not limited to the belt conveying device, but also applies to an image forming apparatus incorporating the belt conveying device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. First Embodiment FIG. 2 is an explanatory view showing a first embodiment of a tandem image forming apparatus to which the present invention is applied. In the figure, a tandem type image forming apparatus includes an image forming unit 22 of four colors (black, yellow, magenta, and cyan in the present embodiment) in a main body housing 21 (specifically, 22a to 22a).
a) a belt unit (belt transport device) including an intermediate transfer belt 230 that is circulated and transported along the direction in which the image forming units 22 are arranged.
23, a recording material supply cassette 24 for accommodating a recording material such as paper (not shown) is provided below the main body housing 21.
The recording material transport path 25 which is the transport path of the recording material from No. 4 is arranged in the vertical direction.

In this embodiment, the image forming units 22 (22a to 22d) are arranged in order from the upstream side in the circulation direction of the intermediate transfer belt 230, for example, for black, yellow, magenta, and cyan (the arrangement is not limited to this. The toner image is formed in any order (not limited to the order), and includes each photoconductor unit 30, each developing unit 33, and one common exposure unit 40. Here, the photoconductor unit 30 includes, for example, a photoconductor drum 31, a charger (a charging roll in this example) 32 for pre-charging the photoconductor drum 31, and a cleaner 34 for removing residual toner on the photoconductor drum 31. Are integrated into a cartridge. The developing unit 33 develops the electrostatic latent image formed by exposure on the charged photosensitive drum 31 by the exposure unit 40 with a corresponding color toner (for example, negative polarity in the present embodiment). is there. Note that reference numeral 35 (35a
35d) to 35d) are toner cartridges for replenishing each developing unit 33 with each color component toner. On the other hand, the exposure unit 40 includes, for example, four semiconductor lasers (not shown), one polygon mirror 42,
An imaging lens (not shown) and a mirror (not shown) corresponding to each photoconductor unit 30 are stored, and light from a semiconductor laser for each color component is deflected and scanned by a polygon mirror 42, and the imaging lens, A light image is guided to a corresponding exposure point on the photosensitive drum 31 via a mirror.

In the present embodiment, the belt unit 23 has an intermediate transfer belt 230 stretched between a plurality of stretching rolls 231 to 235, and corresponds to the photosensitive drum 31 of each photosensitive unit 30. A primary transfer device (primary transfer roll in this example) 51 is provided on the back surface of the intermediate transfer belt 230, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer roll 51, so that the photosensitive drum is charged. The toner image on the transfer belt 31 is electrostatically transferred to the intermediate transfer belt 230 side. In addition, the belt unit 2
Details of 3 will be described later.

Further, a secondary transfer device 52 is disposed at a position corresponding to the tension roll 235 on the downstream side of the most downstream image forming unit 22d of the intermediate transfer belt 230, and the primary transfer on the intermediate transfer belt 230 is performed. The image is secondarily transferred (collectively transferred) to a recording material. In the present embodiment, the secondary transfer device 52 includes a secondary transfer roll 521 that is disposed in pressure contact with the toner image bearing surface of the intermediate transfer belt 230.
And a backup roll (also used as a stretching roll 235 in this example) which is disposed on the back side of the intermediate transfer belt 230 and serves as a counter electrode of the secondary transfer roll 521.
For example, the secondary transfer roll 521 is grounded, and a bias having the same polarity as the toner charging polarity is applied to the backup roll (stretch roll 235).
22. Further, a belt cleaner 53 is disposed on the upstream side of the uppermost-stream image forming unit 22a of the intermediate transfer belt 230 so as to remove residual toner on the intermediate transfer belt 230.

The recording material supply cassette 24 is provided with a feed roll (not shown) for picking up the recording material. Immediately after this feed roll, a takeaway roll 62 for feeding the recording material is provided. A registration roll (registration roll) 63 for supplying a recording material to the secondary transfer portion at a predetermined timing is disposed in the recording material transporting path 25 located immediately before the secondary transfer portion. On the other hand, a fixing device 66 is provided in the recording material conveying path 25 located downstream of the secondary transfer portion.
A discharge roll 67 for discharging the recording material is provided on the downstream side, and the discharged recording material is stored in a storage tray 68 formed on the upper part of the main body housing 21.

In particular, in this embodiment, the belt unit 23 has a structural feature. First, the stretching rolls 231 to 235 used in the present embodiment will be described with reference to FIGS. In FIG.
Reference numeral 1 denotes a steering drive roll that is tilted to control meandering in a lateral direction perpendicular to the running direction of the intermediate transfer belt 230 and drives the intermediate transfer belt 230. Each of the tension rolls 232 and 233 is Intermediate transfer belt 2 for image forming unit 22 (22a to 22d)
30 are surface-applying rolls (all driven rollers) for exposing the primary transfer surface A to a predetermined position, and a tension roll 234 is a biasing spring (for adjusting the bending of the intermediate transfer belt 230). (Not shown) is a tension roll (driven roll) pressed against the intermediate transfer belt 230 with a predetermined tension.
Is a roll (driven roll) which also serves as a backup roll of the secondary transfer device 52 described above.

In this embodiment, the support structure of the steering drive roll 231 is shown in FIGS.
(A) and (b). That is, in this example, the drive motor 244 is fixed to the main body housing 21 (see FIG. 2) in which the belt unit 23 is installed, and the steering drive roll 231 is separate from the frame main body 241 of the belt unit 23. The two shaft portions are rotatably supported on the roll sub-frame 242, and a driven transmission gear 243 is provided on one of the shaft portions 231a, and the driven transmission gear 243 is fixedly connected to the drive motor 244. The gear 245 is meshed. The steering mechanism of the steering drive roll 231 is formed by a shaft 23 of the roll body 231c.
A pivot 251 is provided on a part of the roll sub-frame 242 corresponding to the position closer to 1a, and the pivot 251 is rotatably supported on the frame main body 241. ing. In this example, the roll moving mechanism 252 includes, for example, an engaging pin 2 on a part of the side end wall of the roll subframe 242.
53, the engaging pin 253 is supported by a rotatable eccentric cam 254, and the eccentric cam 254 is appropriately rotated by a steering motor 255. still,
An urging spring 258 for urging the roll sub-frame 242 downward is provided between the roll sub-frame 242 and the frame main body 241, and the engaging pin 253 always contacts the cam surface of the eccentric cam 254. It comes into contact.

Further, in the present embodiment, as shown in FIGS. 2 and 3, a belt walk sensor 260 is provided in the vicinity of the facing roll 233 on the primary transfer surface A of the intermediate transfer belt 230. This belt walk sensor 2
Numeral 60 constantly detects the edge position of the intermediate transfer belt 230. Then, the roll moving mechanism 252
Is a meandering amount (walking amount) of the intermediate transfer belt 230 based on a detection signal from the belt walk sensor 260.
Eccentric cam 254 is rotationally driven by a control signal for correcting the meandering amount, and the steering drive roll 231 is tilted.

Further, in the present embodiment, as shown in FIGS. 5 (a) and 5 (b), the roll moving mechanism 252 includes a steering drive roll 231 having a pivot 251 as a tilting fulcrum, and one end of the steering drive roll 231. Is raised and lowered to tilt the steering drive roll 231. The tilt locus m of the steering drive roll 231 forms a guide surface 256 on a wall surface of the roll sub-frame 242 extending in the roll axis direction. An appropriate number of bearings 257 are provided on the frame main body 241 facing the guide surface 256, and the bearing 257 is restricted and moved on the guide surface 256 to restrict the movement. In particular, in the present embodiment, the tilt locus m of the steering drive roll 231 is regulated as follows. That is, as shown in FIGS. 6A and 6B, the drive transmission gear 245 and the driven transmission gear 243 are gears in which the meshing teeth 245 a and 243 a mesh with each other, but the tilt locus of the steering drive roll 231. The center position Og2 of the drive transmission gear 245 is located within the range of the pressure angle α of the meshing tooth 243a from the center position Og1 of the driven transmission gear 243 with respect to the m-line. Here, the pressure angle α is the radius line r from the center position Og1 of the driven transmission gear 243 at the pitch point of the driven transmission gear 243 meshing tooth 243a surface.
And the tangent s to the tooth profile of the meshing tooth 243a.

In the present embodiment, the pivot (tilt fulcrum) 251 of the steering drive roll 231 is
It is arranged near the shaft portion 231a near the driven transmission gear 243. Specifically, the distance from the pivot 251 position to the center line in the width direction of the meshing portion of the drive transmission gear 245 and the driven transmission gear 243 is D, and the distance from the pivot 251 position to the center line in the width direction of the eccentric cam 254 is L. In this case, the pivot 251 is arranged at a position where A / B is as small as possible. In this example, “D / L” indicates, for example, when the steering drive roll 231 is tilted, the teeth 245 for meshing the drive transmission gear 245 and the driven transmission gear 243.
The ratio is set to 1/20 so that the meshing state of the a and 243a is hardly changed.

Next, an image forming process of the image forming apparatus according to the present embodiment will be described. Each image forming unit 2
2 (22a to 22d) form the respective color component images (toner images) on the photosensitive drum 31 and sequentially and primarily transfer the respective color component images onto the intermediate transfer belt 230 by the primary transfer roll 51. On the other hand, the recording material is supplied from the recording material supply cassette 24, and is conveyed to the secondary transfer portion via the registration roll 63 at a predetermined timing. Then, the intermediate transfer belt 2
The multi-transferred image primarily transferred onto 30 is conveyed to a secondary transfer portion, and is collectively transferred to a recording material by a secondary transfer device 52. After that, the recording material is fixed to the image transferred collectively through the fixing device 66, and then discharged to the storage tray 68 through the discharge roll 67. Each image forming unit 22
Then, the residual toner on the photosensitive drum 31 is
, The residual toner on the intermediate transfer belt 230 is cleaned by the belt cleaner 53.

In such an image forming process, the driving force from the drive motor 244 is transmitted to the steering drive roll 231 via a drive transmission system (drive transmission gear 245, driven transmission gear 243). Moving mechanism 25
Numeral 2 tilts the steering drive roll 231 to perform a steering operation (tilting operation) for controlling the meandering of the intermediate transfer belt 230 in the lateral direction. At this time, the tilt locus m of the steering drive roll 231 is as shown in FIG.
As shown in (a) and (b), the pressure is set so as to fall within the pressure angle α range with respect to the center line connecting the center position Og1 of the driven transmission gear 243 and the center position Og2 of the drive transmission gear 245. Therefore, even if the steering drive roll 231 is tilted, the change in the meshing state between the drive transmission gear 245 and the driven transmission gear 243 is not changed.
43a is displaced substantially in the radial direction, the driven transmission gear 2
43 hardly displaces in the rotational direction.
For this reason, the driven transmission gear 2
43 is hardly displaced in the rotation direction, and accordingly, the occurrence of angular velocity error in the steering drive roll 231 is effectively prevented, and the motion quality of the steering drive roll 231 is kept good. In particular, the tilt locus m of the steering drive roll 231
Is set along the direction of the pressure angle α at the meshing portion of the two gears 243, 245.
43 changes only by sliding along the direction of the pressure angle α of the meshing teeth 243a, 245a.
No rotational force is applied to the driven transmission gear 43, and the situation where the driven transmission gear 243 is displaced in the rotational direction is more reliably avoided.

Also, in the present embodiment, FIG.
As shown in (b), if D / L is set to be small, for example, (D / L) = 1/20, the pivot 2
Since 51 is set in the vicinity of one shaft portion 231a of the steering drive roll 231 corresponding to the position of the rotation drive transmission portion, for example, as shown in FIG. Is smaller than the displacement on the eccentric cam 254 side (for example, 1 /
20) That is, the backlash change in the meshing portion between the driven transmission gear 243 and the drive transmission gear 245, which is the rotational drive transmission unit, can be suppressed to an extremely small value. For this reason, the motion quality of the steering drive roll 231 is deteriorated due to the backlash change of the meshing portion of the rotation drive transmission unit (the drive transmission gear 245 and the driven transmission gear 243), or the rotation drive transmission unit is configured. There is no reduction in gear life.

In this regard, as shown in FIG.
If you want to set the ratio of
A driven transmission gear 243 whose position 51 is a rotational drive transmission unit
Of the steering drive roll 231 on the driven transmission gear 243 side, the displacement of the steering drive roll 231 on the driven transmission gear 243 side inevitably increases. There is a concern that the rush change becomes large, the motion quality of the steering drive roll 231 is deteriorated, and the life of the gear constituting the rotation drive transmission unit is shortened.

[0028]

As described above, according to the belt transport device of the present invention, in a mode having a steering drive roll, a drive source is provided on the installation main body side where the belt transport device is installed. Since a drive transmission system including a drive transmission member having meshing teeth and a driven transmission member is interposed between the drive source and the steering drive roll, the drive source is left on the installation main body side. In addition, the belt transport device can be exchangeably unitized. In particular, in the present invention, the steering drive roll is tilted so that the center position of the drive transmission member is located within the pressure angle range of the meshing teeth from the center position of the driven transmission member with respect to the tilt locus line of the steering drive roll. Since the trajectory is regulated, even when the steering drive roll is tilted, the driven transmission member is hardly displaced in the rotational direction due to a change in the meshing state of the drive transmission member and the driven transmission member, and the steering drive roll is not rotated. Can be effectively suppressed. For this reason, according to the present invention, while maintaining good replacement operability at low cost,
The belt drive and meandering control can be performed stably and accurately. Further, according to the image forming apparatus of the present invention, since the above-described belt conveyance device is incorporated in the image forming apparatus so that the driving and the meandering control of the belt can be stably performed, the belt is used as the image forming surface. Also, it is possible to stably perform the image forming operation on the image forming surface, and it is possible to always obtain good image quality without image disturbance.

[Brief description of the drawings]

FIG. 1A is an explanatory view showing an outline of a belt conveying device according to the present invention, FIG. 1B is an explanatory view showing an operation mechanism of a steering drive roll from a direction B in FIG. 1A, and FIG. )
It is the arrow view seen from the direction of middle C.

FIG. 2 is an explanatory diagram illustrating an overall configuration of an image forming apparatus according to a first embodiment of the present invention;

FIG. 3 is an explanatory diagram illustrating details of a belt conveyance device used in the present embodiment.

FIG. 4A is an explanatory diagram showing an outline of an operation example of a steering drive roll used in the present embodiment, and FIG. 4B is an explanatory diagram showing an operation mechanism of the steering drive roll.

5A is an explanatory view showing a steering mechanism used in the present embodiment, and FIG. 5B is a perspective view of a main part thereof.

6 (a) is a view as seen from the direction of arrow VI in FIG. 4 (b), and FIG. 6 (b) is an explanatory view showing a tilt locus of a steering drive roll.

FIGS. 7A and 7B are explanatory diagrams illustrating a tilt trajectory of the steering drive roll according to a difference in a tilt fulcrum position of the steering drive roll in the embodiment.

[Explanation of symbols]

1 (1a to 1e): roll group, 1a: steering drive roll, 2: endless belt, 3: drive source, 4: drive transmission member, 4a: meshing tooth, 5: driven transmission member, 5a: meshing Tooth, 6 ... Tilt locus regulating means, 7 ... Tilt fulcrum

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Satoshi Nishikawa 2274 Hongo, Fuji Xerox Co., Ltd. Inventor Seiichi Takayama 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. (72) Inventor Masahiro Sato 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd.F-term (reference) DA31 3F023 AA02 BA02 BB01 BC01 CA02 GA05 3F049 AA03 BB11 LA01 LB03

Claims (5)

[Claims] 1. A belt transport device in which a plurality of roll groups including a steering drive roll that is tiltably driven to enable meandering adjustment is arranged in parallel, and an endless belt is wound around these roll groups. A drive transmission member, which is drivably connected to a drive source disposed on the installation main body side where the belt conveyance device is installed and has meshing teeth formed thereon, and a drive transmission member provided on the steering drive roll for meshing the drive transmission member A driven transmission member having teeth meshable with the teeth, and a center position of the driving transmission member positioned within a pressure angle range of the meshing teeth from a center position of the driven transmission member with respect to a tilt trajectory line of the steering drive roll. And a tilt locus restricting means for restricting the tilt locus of the steering drive roll. 2. The belt conveying device according to claim 1, wherein the tilt trajectory regulating means regulates a trajectory of the steering drive roll while maintaining the meshing state of the drive transmission member and the driven transmission member. Characteristic belt transport device. 3. The belt conveying device according to claim 1, wherein the tilt trajectory restricting means sets the tilt fulcrum of the steering drive roll with respect to the axial direction of the steering drive roll at a position where the drive transmission member and the driven transmission member mesh with each other. A belt conveying device which is arranged close to each other. 4. The belt conveying device according to claim 1, wherein the tilt locus restricting means restricts the tilt locus of the steering drive roll along a pressure angle direction at a meshing portion of the drive transmission member and the driven transmission member. Characteristic belt transport device. 5. An image forming apparatus incorporating the belt conveying device according to claim 1.