JP7134720B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus having a detachable belt conveying device.

2. Description of the Related Art Conventionally, among image forming apparatuses equipped with a belt conveying device for conveying a belt, there is known an image forming apparatus equipped with a steering unit that automatically aligns the position of the belt in the width direction. Further, in such an image forming apparatus, there is also known a configuration in which a cleaning device that cleans toner remaining on the belt is swung together with a steering unit (for example, Japanese Patent Application Laid-Open No. 2002-100003).

JP 2015-64503 A

The image forming apparatus described above has the following problems. That is, the shutter provided in the cleaning device is urged by the urging member, and the shutter is opened by coming into contact with the main body side along with the mounting operation. At this time, if the shutter is constantly urged in the closing direction by the urging member, sliding resistance is generated between the shutter and the main body during the steering operation, which may hinder the steering operation.

Therefore, conventionally, a toggle spring has been used that reverses the biasing force of the biasing member when the shutter moves in the opening direction along with the mounting operation of the belt conveying device. However, when such a toggle spring is employed, there is a possibility that the shutter may come into contact with the peripheral member during the process of inserting the belt unit and the shutter may be unintentionally opened. Therefore, there is a possibility that the toner may leak from the outlet during the mounting operation. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an image forming apparatus capable of suppressing unintentional opening of the shutter while suppressing obstruction of the steering operation by the urging force acting on the shutter.

An image forming apparatus for solving the above problems comprises an apparatus main body, an endless belt, a plurality of rollers including a steering roller on which the belt is stretched, and a support section that rotatably supports the plurality of rollers. wherein the steering roller is swingably supported around a steering axis that intersects with the rotation axis of the steering roller; a belt conveying device configured such that when the belt moves to one end in the width direction of the belt, the belt receives an action from the belt and swings in a direction toward the other end; and the belt conveying device. a cleaning device that is held by and swings together with the steering roller to remove toner remaining on the belt; a discharge port that is provided at one end in the longitudinal direction of the cleaning device for discharging the collected toner; a shutter movably provided in the cleaning device for opening and closing the discharge port; a biasing member provided in the cleaning device for biasing the shutter in a closing direction ; an image forming apparatus comprising: a receiving portion that receives a force for rotating the shutter by coming into contact with the apparatus main body as the apparatus is inserted into the apparatus main body; The distance between the receiving portion and the center of swing of the steering roller is within L/2, where L is the distance from the center of swing of the steering roller to the outlet.

It is possible to reduce the sliding load torque of the steering unit while reducing the toner drop at the time of attachment and detachment.

Schematic configuration diagram of the image forming apparatus of the present embodiment Schematic configuration diagram of an intermediate transfer unit of the present embodiment Perspective view of autonomous steering mechanism Configuration diagram of belt cleaner unit of embodiment 1 Sectional view of belt cleaner unit of embodiment 1 Enlarged view of the vicinity of the opening of the belt cleaner unit of the present embodiment 1 is an operation diagram of the autonomous steering mechanism of Embodiment 1, (a) is an overall diagram of the autonomous steering mechanism when the belt is positioned at the center, and (b) is the center of the steering roller when the belt is positioned at the center. Enlarged view of part FIG. 2 is an operation diagram of the autonomous steering mechanism of the first embodiment, where (a) is an overall view of the autonomous steering mechanism with the belt shifted to the right, and (b) is with the belt shifted to the right; Enlarged view of the central part of the steering roller and a diagram explaining the sliding load generated around the rotation shaft Operation diagram when removing the intermediate transfer unit from the main body of the image forming apparatus Configuration diagram of belt cleaner unit of embodiment 2 Cross-sectional view of the belt cleaner of Example 2 FIG. 10 is an operation diagram of the autonomous steering mechanism of Embodiment 2, (a) is an overall diagram of the autonomous steering mechanism when the belt is positioned at the center, and (b) is the center of the steering roller when the belt is positioned at the center; Enlarged view of part Fig. 10 is an operation diagram of the autonomous steering mechanism of the second embodiment, where (a) is an overall view of the autonomous steering mechanism with the belt shifted to the right, and (b) is shown with the belt shifted to the right; Enlarged view of the central part of the steering roller and a diagram explaining the sliding load generated around the rotation shaft

Embodiments of the present invention will be described below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to them. .

FIG. 1 is an explanatory diagram of an image forming apparatus. As shown in FIG. 1, the image forming apparatus 100 is an intermediate transfer type color digital printer having four image forming units 109 along an intermediate transfer belt 101 . The surface of each of the four photosensitive drums 103 as image carriers is uniformly charged by charging rollers 104 . Yellow, magenta, cyan, and black image signals are input to the laser scanner 105, respectively, and the surface of the drum is irradiated with laser light according to the image signals to neutralize the charge and form a latent image. The latent images formed on the drum are developed with yellow, magenta, cyan, and black toners by developing devices 106, respectively. The toner images developed on the drums are sequentially primary-transferred onto the intermediate transfer belt 101 by the primary transfer roller 107 to form a full-color toner image on the surface of the intermediate transfer belt 101 . The residual toner remaining on the photosensitive drum 103 is collected by the drum cleaner 108 .

On the other hand, the transfer material P such as paper fed from the cassette paper feed unit 120 by the paper feed roller 121 is sent toward the registration roller 122, and is further transferred to the secondary transfer unit in synchronism with the toner image on the intermediate transfer belt. Sent to T2. The toner image on the intermediate transfer belt is transferred to the transfer material P by the inner secondary transfer roller 110 and the outer secondary transfer roller 111 at the secondary transfer portion T2 and sent to the fixing device 130 . After the toner image is fixed on the transfer material P sent to the fixing device 130 by heat and pressure in the fixing device 130, the transfer material P is discharged out of the machine. A belt cleaner 102 collects residual toner on the intermediate transfer belt 101 that has not been transferred in the secondary transfer portion T2. In this embodiment, the inner secondary transfer roller 110 is a drive roller that drives the intermediate transfer belt 101, and therefore is sometimes referred to as the drive roller 110 hereinafter.

FIG. 2 is an explanatory diagram of an intermediate transfer unit. An intermediate transfer unit 200 as a belt unit is a belt conveying device having an intermediate transfer belt 101 stretched by a plurality of tension rollers and rotated and conveyed. The intermediate transfer belt 101 is an endless belt member made of polyimide or the like. The intermediate transfer belt 101 is stretched by a drive roller 110 , a steering roller 112 , tension rollers 113 and 114 and a primary transfer roller 107 and assembled integrally to form an intermediate transfer unit 200 . Each roller around which the intermediate transfer belt 101 is stretched is rotatably supported by a frame 201 as a support section. Also, the intermediate transfer unit 200 is detachably provided in the image forming apparatus main body 100 . As described above, the drive roller 110 also serves as an inner secondary transfer roller forming the secondary transfer portion T2. Further, the steering roller 112 is biased by a compression spring 213 so as to press the intermediate transfer belt 101 from its inner surface, and also serves as a tension roller that applies tension. As shown in FIG. 2, the primary transfer rollers 107 form a primary transfer portion T1 together with the photosensitive drums 103 via the intermediate transfer belt 101, and superimpose yellow, magenta, cyan, and black toner images on the intermediate transfer belt 101. A color image is formed by transferring with

FIG. 3 is a perspective view of an autonomous steering mechanism. The steering roller 112 is supported at both ends by steering roller support members 211 forming a steering unit so as to be driven by the rotation of the intermediate transfer belt 101 . Both ends of the steering roller 112 are provided with sliding ring portions 212 whose rotation is restricted. In this embodiment, the sliding ring portion 212 includes a bearing 212a (see FIG. 7A) and serves as a bearing member for the steering roller 112 as well. Further, the sliding ring portion (bearing member) 212 is slidably supported on the steering roller supporting member 211 in the direction of the arrow X, and the steering roller 112 is urged against the intermediate transfer belt 101 by the compression spring 213 . is doing. The sliding ring portion 212 is provided at the axial end portion of the steering roller 112 . The steering roller support member 211 is tiltably supported with respect to the frame 201 via a rotating shaft 214 . That is, the steering roller 112 is supported so as to be rotatable (swingable) around the steering axis (around the rotation shaft 214 ) that intersects the rotation axis of the steering roller 112 .

4 is a perspective view of the belt cleaner unit 301, FIG. 5 is a sectional view of the belt cleaner unit, and FIG. 6 is an enlarged view of the belt cleaner opening. A belt cleaner unit 301 as a cleaning device is connected to the steering unit by a connecting member 313 and held integrally with the steering unit. The belt cleaner unit has a belt cleaner 102 as a cleaning member. In this embodiment, the belt cleaner 102 employs a cleaning blade that contacts the belt. The belt cleaner 102 is supported by a belt cleaner container 303 , contacts the intermediate transfer belt 101 from one end to the other in the width direction of the intermediate transfer belt 101 , and removes toner remaining on the intermediate transfer belt 101 . The toner collected by the belt cleaner container 303 is conveyed by the collected toner conveying means 305 arranged in the collected toner conveying path 304 and discharged from the opening 306 as a toner discharge port. The opening 306 is provided at one end in the longitudinal direction of the cleaning device (the other end in the rotation axis direction of the steering roller).

The collected toner transport path 304 is connected to the main body transport path through an opening 306 . The opening 306 is configured to be openable and closable by a shutter 307 . The shutter 307 is integrated with a gear 311A. A rotating member 310 is rotatably supported by the belt cleaner container 303 and the support member 312 , and the shutter 307 is configured to be movable by rotating the rotating member 310 . The rotating member 310 is integrated with a gear 311B. The gears 311A and 311B are drivingly connected to each other, and the rotation of the rotating member 310 causes the shutter 307 to open and close. Specifically, as the intermediate transfer unit 200 is inserted, the rotating member is rotated to move the shutter 307 from the closed position to close the opening 306 to the open position to open the opening 306 . Further, the belt cleaner container 303 is provided with an elastic member 308 as a biasing member that biases the shutter 307 in the closing direction. In this embodiment, the elastic member 308 is a torsion coil spring provided coaxially with the gear 311B.

The rotating member 310 forms a contact surface 314 by coming into contact with a protrusion 309 provided on the main body side. In this embodiment, as shown in FIG. 7B, the contact surface 314 has a semi-cylindrical protrusion on the surface that contacts the protrusion 309 . This convex portion extends in a direction intersecting with the rotation axis of the steering roller. As a result, the protrusion 309 and the contact surface 314 are configured to line-contact with each other during the steering operation so as not to hinder the steering operation. That is, the contact surface 314 is formed with a convex portion having a curved surface. Note that this convex portion may be provided on the protruding portion 309 side without being provided on the contact surface 314 .

In Example 1, the contact surface 314 is arranged on the thrust axis 401 of the rotating shaft 214 and on the axis 400 perpendicular to the thrust axis 401 .

When the image forming apparatus is operated, residual toner on the intermediate transfer belt 101 is scraped off from the intermediate transfer belt 101 by the belt cleaner 102 . The scraped toner falls into the collected toner conveying path 304, and the accumulated toner is conveyed toward the opening 306 by the collected toner conveying means 305, and the intermediate transfer belt 101 is operated, which occurs during operation. The overshoot will be corrected by the automatic steering mechanism.

FIG. 7 and FIG. 8 are diagrams showing the operation of the autonomous steering mechanism and the operation of the rotating member 310 and the contact portion 314 of the belt cleaning unit 301 at that time. The abutting portion 314 is a receiving portion 314 that abuts against the image forming apparatus main body 100 as the intermediate transfer unit 200 is inserted and receives a force for rotating the rotating member 310 . In the state shown in FIG. 7A, in which the intermediate transfer belt 101 is stretched over the axial center of the steering roller 112 with good balance, the belt cleaning unit maintains a substantially horizontal state as shown in FIG. 7B. there is However, as shown in FIG. 8(a), when the intermediate transfer belt 101 deviates to the right (one side in the axial direction), a frictional force is generated between the intermediate transfer belt 101 and the slide ring portions 212 at both ends. That is, when the intermediate transfer belt 101 moves toward one end in the belt width direction while the intermediate transfer belt 101 is being driven, the intermediate transfer belt 101 is acted upon by the sliding ring portion 212 . This action allows the steering roller to swing in the direction toward the other end of the intermediate transfer belt 101 . At this time, the contact widths of the intermediate transfer belt 101 and the sliding ring portions 212 at both ends are different on the left and right sides, and the frictional force on the right side (one side in the axial direction) having a larger contact width is greater than that on the left side (the other side in the axial direction). The steering roller 112 tilts in the direction of lowering the right side. As a result, the alignment between the drive roller 110 and the steering roller 112 is lost, and the intermediate transfer belt 101 shifts to the left at the winding portion of the steering roller 112, thereby correcting the belt shift. At this time, if a load that prevents the tilting motion of the steering roller 112 is applied, the correction of the belt becomes insufficient and the belt shift occurs.

However, as shown in FIG. 4, in the present embodiment, the belt cleaner unit 301 is also connected to the steering unit, so it tilts in the same manner as the steering roller tilts. The sliding load torque at the center of the rotation shaft 214 (oscillation center) at that time is assumed to be _Tf1 . Letting L _f1 be the distance from the center of the rotary shaft 214 to the contact surface 314 and F be the sliding load generated on the contact surface, T _f1 =FL _f1 . When the contact surface 314 is provided in the vicinity of the opening 306 located at the distance Ls from the center of the rotating shaft 214, Ts is the sliding load torque at the center of the rotating shaft 214. Ts=FLs. Since the distance from the center of the rotating shaft 214 is L _f1 <Ls, the sliding load torque is also T _f1 <Ts. That is, it is possible to reduce the steering roller tilting load due to contact. Further, as shown in FIG. 9, the intermediate transfer unit 200 can be detached from the image forming apparatus 100 by opening and closing the main body door 115 . In this configuration, since the elastic member 308 presses the shutter 307 in one direction in the closing direction, the shutter 307 is not unintentionally left open, so that the fall of toner can be reduced.

10 is a perspective view of the belt cleaner unit, FIG. 11 is a sectional view of the belt cleaner unit, and FIG. 6 is an enlarged view of the belt cleaner opening. Components having the same reference numerals as those of the first embodiment have the same configurations as those of the first embodiment unless otherwise specified, and thus description thereof is omitted.

The second embodiment differs from the first embodiment in that the contact portion 314 is arranged at a position closer to the rotating shaft 214 than the position of the opening 306 .

As the belt cleaner unit 301 is inserted, the rotating member 310 contacts a contact surface 315 provided on the main body and rotates. The contact surface 315 is a plane orthogonal to the steering axis, and is configured so that the rotating member 310 is not rotated by the steering operation of the steering roller.

When the image forming apparatus is operated, residual toner on the intermediate transfer belt 101 is scraped off from the intermediate transfer belt 101 by the belt cleaner 102 . The scraped toner falls into the collected toner conveying path 304, and the accumulated toner is conveyed toward the opening 306 by the collected toner conveying means 305, and the intermediate transfer belt 101 is operated, which occurs during operation. The overshoot will be corrected by the automatic steering mechanism.

12 and 13 are diagrams showing the operation of the autonomous steering mechanism and the operation of the rotating member 310 and the contact portion 314 of the belt cleaning unit 301 at that time. In the state shown in FIG. 12A, in which the intermediate transfer belt 101 is stretched around the axial center of the steering roller 112 with good balance, the belt cleaning unit 301 maintains a substantially horizontal state as shown in FIG. 12B. ing. However, as shown in FIG. 13(a), when the intermediate transfer belt 101 deviates to the right (one side in the axial direction), a frictional force is generated between the intermediate transfer belt 101 and the sliding ring portions 212 at both ends. At this time, the contact widths of the intermediate transfer belt 101 and the sliding ring portions 212 at both ends are different on the left and right sides, and the frictional force on the right side (one side in the axial direction) having a larger contact width is greater than that on the left side (the other side in the axial direction). The steering roller 112 tilts in the direction of lowering the right side. As a result, the alignment between the drive roller 110 and the steering roller 112 is lost, and the intermediate transfer belt 101 shifts to the left at the winding portion of the steering roller 112, thereby correcting the belt shift. At this time, if a load that prevents the tilting motion of the steering roller 112 is applied, the correction of the belt becomes insufficient and the belt shift occurs.

However, as shown in FIG. 10, since the belt cleaner unit 301 is also connected to the steering unit in this embodiment, it tilts in the same manner as the steering roller tilts. Assuming that the sliding load torque at the center of the rotating shaft 214 at that time is T _f1 , T _f1 is the distance L _f2 from the center of the rotating shaft 214 to the contact surface 314 , and the load generated at the contact surface is F, T It can be expressed by _f1 =FL _f1 . When the contact surface 314 is provided near the opening 306 at a distance L _s from the center of the rotation shaft 214, Ts is the sliding load torque at the center of the rotation shaft 214. Ts _{=FL s .} . Since the distance from the center of the rotating shaft 214 is L _f2 <L _s , the sliding load torque is also T _f2 <T _s . That is, it is possible to reduce the steering roller tilting load due to contact. Further, as shown in FIG. 9, the intermediate transfer unit 200 can be detached from the image forming apparatus 100 by opening and closing the main body door 115 . In this configuration, since the elastic member 308 presses the shutter 307 in the closing direction, the shutter 307 is not unintentionally kept open, so that toner falling can be reduced.

In this embodiment, when the distance L from the swing center of the steering roller to the opening 306 is L, the distance between the contact surface 314 and the swing center of the steering roller is , within L/2. More preferably, the distance between the contact surface 314 and the pivotal center of the steering roller is within L/10. Further, in this embodiment, the distance between the contact surface 314 and the swing center of the steering roller is set within 10 mm with respect to the rotation axis direction of the steering roller.

In this embodiment, the shutter 307 and the rotating member 310 are formed as separate members and are driven and connected to each other, but the shutter 307 is configured to move (rotate) while directly abutting the protrusion 309 on the main body side. may be That is, the shutter 307 may be provided with a receiving portion 314 that receives a force to rotate the shutter 307 by coming into contact with the image forming apparatus main body 100 as the intermediate transfer unit 200 is inserted. In this case, the distance between the receiving portion 314 and the center of the rotating shaft 214 should be L/2.

REFERENCE SIGNS LIST 100 Image forming apparatus 101 Intermediate transfer belt 102 Belt cleaner 103 Photoreceptor drum 104 Charging roller 105 Laser scanner 106 Developing device 107 Primary transfer roller 108 Drum cleaner 109 Image forming unit 110 Secondary transfer inner roller (driving roller)
REFERENCE SIGNS LIST 111 secondary transfer outer roller 112 steering roller 113 tension roller 114 tension roller 115 main body door 120 cassette paper supply section 121 paper supply roller 130 fixing device 200 intermediate transfer unit 201 frame 211 steering roller support member 212 sliding ring section 212a bearing 213 compression spring 214 rotating shaft 301 belt cleaner unit 303 belt cleaner container 304 recovered toner conveying path 305 recovered toner conveying means 306 opening 307 shutter 308 elastic member 309 protrusion 310 rotating member 311 gear 313 connecting member 315 contact surface

Claims (5)

a device body;
A belt conveying device that is attachable to and detachable from the device main body, comprising an endless belt, a plurality of rollers including a steering roller for stretching the belt, and a support portion that rotatably supports the plurality of rollers. The steering roller is supported so as to be swingable about a steering axis that intersects with the rotation axis of the steering roller. a belt conveying device configured so that the belt can swing in a direction toward the other end by receiving an action from the belt;
a cleaning device held by the belt conveying device and swinging together with the steering roller to remove toner remaining on the belt;
a discharge port provided at one end in the longitudinal direction of the cleaning device for discharging collected toner;
a shutter movably provided in the cleaning device for opening and closing the outlet;
a biasing member provided in the cleaning device for biasing the shutter in a closing direction;
An image forming apparatus comprising: a receiving portion provided in the cleaning device, and receiving a force for rotating the shutter by coming into contact with the apparatus main body as the belt conveying device is inserted into the apparatus main body,
With respect to the rotation axis direction of the steering roller, the distance between the receiving portion and the steering roller swing center is within L/2, where L is the distance from the swing center of the steering roller to the discharge port. An image forming apparatus characterized by: 2. The image forming apparatus according to claim 1, wherein a distance between said receiving portion and a swing center of said steering roller is within L/10 with respect to the rotation axis direction of said steering roller. 3. The image forming apparatus according to claim 1, wherein the receiving portion is provided within a range of 10 mm from a position where the steering axis is provided with respect to the rotation axis direction of the steering roller. Any one of the surfaces with which the cleaning device and the device main body contact each other has a semi-cylindrical projection extending in a direction intersecting the rotation axis of the steering roller. 3. The image forming apparatus according to any one of 3. A rotatable member rotatably supported by the cleaning device and drivingly connected to the shutter, the rotatable member rotating in accordance with the insertion operation of the belt conveying device to move the shutter from a closed position to an open position. 5. The image forming apparatus according to any one of claims 1 to 4, further comprising a rotatable member that allows the rotatable member to rotate, and wherein the receiving portion is provided on the rotatable member.

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