JPH0656293A - Endless belt conveying device for image forming device - Google Patents

Abstract

PURPOSE:To prevent a belt end section from being buckled by the compliance when the belt tension is released. CONSTITUTION:An edge guide holding member 38 is provided with the first coupling section 38a coupled with a support member 28 and the second coupling section 38b coupled with an edge guide 27. When the belt tension of a conveyor belt 7 is released, the edge guide 27 is moved in the direction separating from the conveyor belt 7, and it is separated from the conveyor belt 7. The first coupling section 38a of the edge guide holding member 38 is coupled with the support member 28, the second coupling section 38b is coupled with the edge guide 27, and the edge guide 27 is kept separated from the conveyor belt 7. No spring force of a spring 29 is applied to the side edge of the conveyor belt 7, and the conveyor belt 7 is never buckled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt conveying device for use in an image forming apparatus such as an electrophotographic copying machine or a printer and having an endless conveying belt for conveying a transfer material. The present invention relates to an endless belt conveyance device in an image forming apparatus including an edge guide for suppressing meandering.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic copying machine or a printer, when a toner image formed on a photosensitive drum is transferred to a transfer material such as transfer paper, a transfer material such as a paper tray is accommodated. The transfer material supplied from the means is carried by an endless transfer belt and is transferred to the transfer position of the photosensitive drum. Then, after the toner is transferred from the photosensitive drum to the transfer material, the transfer material is further transported to the fixing device by the transport belt in order to fix the toner image transferred on the transfer material.

By the way, in such an endless belt conveying device, when the conveying belt is rotated, it tends to come close to one of the left and right sides, that is, meandering. By fixing the edge guides at both ends and abutting the edge guides on the side edges of the conveyor belt to guide the conveyor belt,
The left and right sides of the conveyor belt are prevented from shifting.

[0004]

However, in such an edge guide, when the side edge of the conveyor belt is undulated, the conveyor belt comes into contact with the edge guide in an undulated state. Guide the conveyor belt in a wavy state. Therefore, when, for example, a straight developed image on the photosensitive drum is transferred to the transfer paper on the undulating portion of the conveyor belt, a curved line along the undulating shape of the side edge of the conveyor belt. It is transferred in the shape of a circle and causes a transfer failure.

Therefore, in order to prevent such a transfer failure, an edge guide called a compliant edge guide device is considered (Japanese Patent Application No. Hei 2-279449).
issue). As shown in FIG. 8, this compliant edge guide device supports the edge guide 27 on the shaft portion 28a of the support member 28 so as to be movable in the axial direction, and also supports the spring 2
9 is used to push the side edge 7a of the conveyor belt 7 with a predetermined force. Further, in this compliant edge guide device, the biasing force of the conveyor belt 7 and the spring 2 are used.
When the pressing force of 9 is balanced, the edge guide 27
Guides the conveyor belt 7. In addition,
The support member 28 rotatably supports the rotating shaft 10a of the driven roller 10 by means of bearings.

According to this compliant edge guide, when the conveyor belt 7 is undulating, the compliant edge guide moves in the axial direction in accordance with the undulation, so that the conveyor belt side does not move. As a result, for example, a straight line on the photosensitive drum is wavy.
The upper transfer paper will be transferred in a straight line.

By the way, in this compliant edge guide device, the edge guide 27 is used as the conveyor belt 7.
The pressing force of the spring 29 that abuts against is set as follows. That is, the conveyor belt 7 is in a state in which the belt tension is applied to the conveyor belt 7 in a tensioned state and the tension is comparatively large, and the pressing force of the edge guide 27 by the spring 29 causes the conveyor belt 7 to be conveyed in the state where the belt tension is applied. It is set so as to balance with the force due to the deviation of the belt 7.

Since the conveyor belt 7 to which the belt tension is applied has a relatively high strength, it does not buckle even if the pressing force of the spring 29 is applied. On the other hand, when the belt tension is not applied to the conveyor belt 7, the conveyor belt 7 is soft and has a relatively small strength.
When the pressing force is applied, the side edge 7a of the conveyor belt 7 causes buckling α as shown in FIG. For this reason,
There is a problem that the durability of the conveyor belt 7 is impaired and the belt has a short life.

The present invention has been made in view of the above problems, and an object thereof is to prevent the belt end portion from buckling by a compliant edge guide at the time of releasing the belt tension to thereby convey the conveyor belt. It is an object of the present invention to provide an endless belt conveying device in an image forming apparatus, which can improve the durability of the belt and extend the life of the belt.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 provides at least a plurality of rollers around which an endless conveyor belt for conveying a transfer material in one direction is stretched. An edge guide that guides the side edge of the conveyor belt is provided on one roller so as to be separable from the side edge of the conveyor belt. The edge guide is brought into contact with the side edge of the conveyor belt by a predetermined force of the spring. Further, the edge guide holding member can hold the edge guide in a state of being separated from the side edge of the conveyor belt.

Therefore, when the belt tension is released from the conveyor belt by the belt tension releasing device, the edge guide holding member holds the edge guide in a state of being separated from the side edge of the conveyor belt. The spring force of the spring that presses the edge guide is not applied to. As a result, the conveyor belt does not buckle and the durability is improved.

According to a second aspect of the present invention, at least one of a plurality of rollers around which an endless conveyor belt that conveys the transfer material in one direction is stretched, and an edge that guides a side edge of the conveyor belt. The guide is provided so as to be able to come into contact with and separate from the side edge of the conveyor belt. The edge guide is brought into contact with the side edge of the conveyor belt by a predetermined force of the spring. Further, the edge guide holding member can hold the edge guide in a state of being separated from the side edge of the conveyor belt.

When the belt tension releasing device releases the belt tension from the conveyor belt, the belt tension releasing operation interlocking means operates the edge guide holding member in association with the belt tension releasing operation to move the edge guide to the conveyor belt. Hold it away from the side edges.

Accordingly, when the belt tension is released from the conveyor belt, the edge guide is automatically held in a state of being separated from the side edge of the conveyor belt, and the spring force of the spring for pressing the edge guide is applied to the conveyor belt. I will not be able to.
As a result, the conveyor belt does not buckle and the durability is improved. Moreover, when the belt tension is released from the conveyor belt, the edge guide automatically separates from the side edge of the conveyor belt, which prevents forgetting to release the spring force of the edge guide applied to the conveyor belt. With a simple operation, the conveyor belt can be reliably protected.

Further, in the invention of claim 3, the belt tension releasing operation interlocking means is provided with an edge guide pressing force releasing cam, and the edge guide pressing force releasing cam also serves as the edge guide holding member. Therefore, the edge guide pressing force releasing cam separates the edge guide from the side edge of the conveyor belt in conjunction with the belt tension releasing operation, and
It comes to hold in the separated state.

Further, according to the invention of claim 4, an edge guide and an edge guide holding member are respectively provided at the left and right ends of the roller, and the left and right edge guide holding member interlocking means interlock the left and right edge guide holding members. ing. As a result, the left and right edge guide holding members are operated by one operation, so that the left and right edge guides are simultaneously separated from the side edge of the conveyor belt and are held in the separated state.

Further, the invention of claim 5 is that the endless belt that conveys the transfer material is a photoconductor belt, and the invention of claim 6 is that the endless belt is an intermediate belt, and the invention of claim 7 is further provided. Is a transfer belt, and the invention of claim 8 defines that the endless belt is continuous paper.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a developing device, a transfer device, a fixing device, and a paper feeding, carrying, and discharging device in a tandem type digital color copying machine to which an embodiment of an endless belt carrying device according to the present invention is applied. FIG. It is needless to say that the present invention is not limited to such a tandem type digital color copying machine, and can be applied to other types of copying machines and other image forming apparatuses.

As shown in FIG. 1, in this digital color copying machine 1, four photosensitive drums 2Y, 2M, 2 corresponding to each color of yellow Y, magenta M, cyan C, and black K are provided.
C and 2K are respectively arranged in this order from the right side in the drawing, that is, at a predetermined distance from the paper supply side. In the vicinity of the outer circumference of these photosensitive drums 2Y, 2M, 2C, 2K,
Primary chargers 3Y, 3M, 3C and 3K are arranged respectively. These primary chargers 3Y, 3M, 3C, 3K are provided on the surfaces of the corresponding photoconductor drums 2Y, 2M, 2C, 2K, for example, -500-8.
It is uniformly charged to 00V.

Further, exposure devices 4Y, 4 such as a laser beam exposure device are provided downstream of the primary chargers 3Y, 3M, 3C, 3K near the outer circumferences of the photoconductor drums 2Y, 2M, 2C, 2K in the rotational direction.
M, 4C, 4K are disposed, further developing devices 5Y, 5M, on the downstream side in the rotational direction of the exposure devices 4Y, 4M, 4C, 4K near the outer periphery of each photoconductor drum 2Y, 2M, 2C, 2K, respectively. 5C and 5K are arranged.
The exposure devices 4Y, 4M, 4C, 4K irradiate a color-separated light image or a light image corresponding thereto to form an electrostatic latent image on the photoconductor drums 2Y, 2M, 2C, 2K, and a developing device. 5Y, 5M, 5C, and 5K develop the electrostatic latent image on the photoconductor drums 2Y, 2M, 2C, and 2K formed in this way with toner to form a visible image.

A transfer device 6 is arranged under each of the photoconductor drums 2Y, 2M, 2C and 2K. The transfer device 6 includes an endless conveyor belt 7 of a predetermined length arranged in contact with each of the photoconductor drums 2Y, 2M, 2C and 2K, and the lowermost part of each of the photoconductor drums 2Y, 2M, 2C and 2K. The transfer chargers 8Y, 8M, 8C and 8K are arranged to face each transfer point.

The conveyor belt 7 is formed by integrally forming a transfer material carrying sheet made of a dielectric material and a conveying sheet made of an insulating material or a high resistance material, for example, polyethylene terephthalate (PET) or polyvinylidene fluoride resin film. It is composed of a transport sheet made of a dielectric material. Further, the conveyor belt 7 is a driven roller 10 which is a driven roller arranged on the opposite side of a drive roller 9 connected to a dedicated motor (not shown) having excellent constant speed.
A fixed tension is applied between the two and to stretch them, and the drive roller 9 rotates them in the direction of arrow A, that is, in the counterclockwise direction. Further, the conveyor belt 7 is also stretched over a peeling roller 12 and an idler roller 13 of a transfer material peeling means 11 provided at a transfer material peeling position.

The transfer chargers 8Y, 8M, 8C and 8K are corona chargers, for example, different voltages are applied in the range of +4.2 KV to +12.0 KV, and the transfer current is +50 μA to +2000 μA. To be done. By this transfer current, the toner on the photoconductor drums 2Y, 2M, 2C, K is transferred onto the transfer paper 1
7 is electrostatically adsorbed.

In the vicinity of the driving roller 9 of the conveyor belt 7,
The transfer charging device 14 is disposed so as to face the transfer charging device 14 with the transfer charging device 14 sandwiching the transfer belt 7 and the transfer charging device 14.
And a suction roller 15 which is a guide member for guiding the sheet to the conveyor belt 7. Then, the transfer paper 17 such as the paper stored in the paper supply tray 16 is fed onto the conveyor belt 7 by the feed roller 18 at a predetermined timing, and is attracted to the conveyor belt 7 by the attraction charger 14 and the attraction roller 15. To be done.

On the other hand, the transfer material peeling means 11 includes a charge removing member 20 for weakening the electrostatic attraction force of the conveyor belt 7 and the transfer paper 1.
A peeling claw 26 for peeling 7 from the conveyor belt 7 is provided. Further, a fixing device 21 is provided on the downstream side of the transfer material peeling means 11, and the toner image transferred onto the transfer paper 17 is fixed by the fixing device 21. The transfer paper 17 that has been fixed is stored in the paper discharge tray 22.

Further, on the inside and outside of the conveyor belt 7, an inner charge-eliminating charger 23 and an outer charge-eliminating charger 24, which constitute a charge-eliminating means for eliminating charge on the conveyer belt 7, are provided so as to face each other. Further, a conveyor belt cleaning means 25 for cleaning the conveyor belt 7 is disposed downstream of the drive roller 9.

Hereinafter, in the process of forming a full-color image by the digital color copying machine of the present embodiment having such a configuration, the visible image forming process by the developing of each developing device 5Y, 5M, 5C, 5K and the conveying belt 7 The steps of adsorbing the transfer paper 17 onto the sheet and transferring the sheet will be described.

The transfer paper 17 attracted to the conveyor belt 7 by the adsorption charger 14 and the adsorption roller 15 is transferred to the conveyor belt 7.
When it reaches the transfer point of the yellow Y photoconductor drum 2Y, the Y toner image is first transferred from the photoconductor drum 2Y to the transfer paper 17. Next, transfer paper 1
7 is conveyed by the conveyor belt 7, and the toner image of magenta M is transferred from the photosensitive drum 2M onto the toner image of Y on the transfer paper 17 in an overlapping manner. Thereafter, the cyan C toner image and the black K toner image are sequentially transferred so as to be superimposed on the transfer toner image on the transfer paper 17. In this way, four-color full-color multiple transfer is performed.

When the full-color multi-transfer of four colors is completed, the transfer paper 17 is discharged by the charge removing member 20 of the transfer material peeling means 11, and the rigidity of the transfer paper 17 is used to remove the transfer paper 17 by the peeling roller 12. The transfer paper 17 is separated from the conveyor belt 7 by the separation claw 26 while being forcibly separated.

By the way, the conveyor belt 7 in such a digital color copying machine is used as the transfer paper 1 during normal operation.
In order to surely convey 7 and to surely transfer the image on the photoconductor drum to the transfer paper 17, a belt tension is applied to keep the image tight. Therefore, a color copying machine is usually provided with a belt tension applying device for applying a belt tension to the conveyor belt. In addition, the conveyor belt 7
The belt tension can be released and the belt can be in a bent state when not in operation.

FIG. 2 is a perspective view showing such a belt tension applying device and a belt tension releasing device. Note that FIG.
The term “left and right” used in the description of 1 indicates left and right with respect to the transfer paper conveyance direction.

As shown in FIG. 2, edge guides 27, 27 of a compliant edge guide device similar to that shown in FIG. 8 are provided at the left and right ends of the driven roller 10 so as to be movable in the axial direction. ing. Although not shown in FIG. 2, these edge guides 27, 27 are adapted to push the side edge of the conveyor belt 7 with a predetermined force by a spring as shown in FIG.

The left and right support members 28, 28 which respectively support the left and right ends and the left and right edge guides 27, 27 of the driven roller 10 are connected to the slide housings 30, 30, respectively.
Guided by slide rails 32, 32 fixed to the left and right frames 31, 31, it is slidable in the belt tension applying direction.

Further, spring supporting members 33, 33 are fixedly mounted on the left and right frames 31, 31, respectively, and bent portions 33a, 33 at one end of these spring supporting members 33, 33 are fixed.
a is a spring 34 for applying tension to the conveyor belt 7.
Are connected at one end. The other end of the spring 34 has the bent portions 30a, 30 of the slide housings 30, 30.
It is connected to a. In that case, the springs 34, 34
Is provided between the bent portions 30a, 30a; 33a, 33a while being pulled by a predetermined amount. Therefore, the driven roller 10 is constantly urged in the belt tension applying direction via the slide housings 30, 30 and the support members 28, 28 by the spring force of these springs 34, 34.

Further, tension releasing cams 35, 35 are rotatably provided on the left and right frames 31, 31. These tension releasing cams 35, 35 are provided with one rotary shaft 35a.
Therefore, the left and right tension releasing cams 35, 35 are synchronously rotated.
A tension release handle 36 is connected to the left tension release cam 35, and the left and right tension release cams 35, 35 can be rotated by the tension release handle 36.

Furthermore, the releasing force of the tension releasing cam 35 is applied to the slide housings 30, 30 on the left and right frames 31, 31.
The releasing force transmitting members 37, 37 for transmitting to the sheet are provided slidably in the transfer sheet conveying direction. The release force transmitting members 37, 37 are respectively provided with a first bent portion 37a and a second bent portion 37a.
The bent portion 37b is provided, and the first bent portion 37a, 3
The cam surfaces of the tension release cams 35, 35 are in contact with 7a. The second bent portions 37b, 37b are engageable with the bent portions 30a, 30a of the slide housings 30, 30.

In the belt tension applying device and the belt tension releasing device constructed as described above, the second bent portions 37b, 37b are slightly separated from the bent portions 30a, 30a in the state shown in FIG. The driven force of the spring 34 sets the driven roller 10 to the belt tension applying position. When the tension release handle 36 is operated to rotate the tension release cams 35, 35 in order to release the tension from the belt tension applied state, the cam surfaces of the tension release cams 35, 35 form the first bent portions 37a, 37a. It is pressed in the direction opposite to the belt tension applying direction. Thereby, the release force transmitting member 3
7, 37 move in the opposite direction, and the bent portions 37b, 37b contact the bent portions 30a, 30a.

When the tension releasing cams 35, 35 are further rotated, the releasing force transmitting members 37, 37 further move in the opposite directions, and in conjunction with this, the slide housings 30, 30, the supporting members 28, 28 and the driven rollers. Both 10 move in the opposite direction against the spring force of the springs 34, 34. As a result, the belt tension applied to the conveyor belt 7 is released, and the conveyor belt 7 changes from a taut state to a bent state.

FIG. 3 is a partially enlarged sectional view similar to FIG. 8, showing an embodiment of the endless belt conveying device according to the present invention. The same components as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted (the same applies to other embodiments described below).

As shown in FIG. 3A, in this embodiment, an edge guide holding member 38 for holding the edge guide 27 in a state of being separated from the conveyor belt 7 is provided. The edge guide holding member 38 has a first engaging portion 38 a that engages with the support member 28 and a second engaging portion 38 b that engages with the edge guide 27. The figure (b)
As shown in FIG. 3, reference numeral 38c is an opening for preventing interference with the rotary shaft 10a of the driven roller 10.

In the edge guide holding member 38 of this embodiment constructed as described above, when the belt tension to the conveyor belt 7 is released, the edge guide 27 resists the spring force of the spring 29 in the direction away from the conveyor belt 7. Then, it is moved to be separated from the conveyor belt 7. Then, the first engaging portion 38a of the edge guide holding member 38 is attached to the support member 2
8 and engages the second engaging portion 38b with the edge guide 2
By engaging with 7, the edge guide 27 is held in a state of being separated from the conveyor belt 7.

When the edge guide 27 is held in a state of being separated from the conveyor belt 7 in this way, the spring force of the spring 29 is not applied to the side edge 7a of the conveyor belt 7 via the edge guide 27. Even when the belt tension of the conveyor belt 7 is released, the side edge 7a of the conveyor belt 7 does not buckle.

FIG. 4 is a diagram showing another embodiment of the present invention. In contrast to the above-described embodiment, in this embodiment, FIG.
As shown in FIG. 3, a first sprocket 39 is rotatably provided on the support member 28, and an edge guide pressing force releasing cam 40 is provided so as to rotate coaxially and synchronously with the first sprocket 39. The edge guide pressing force releasing cam 40 has a cam surface 40a formed by changing the wall thickness in the rotation axis direction in the circumferential direction.

Further, a second sprocket 41 is fixedly mounted on the rotary shaft 35a of the tension releasing cam 35. And the first
A bead chain 42 is installed between the second sprocket 39 and 41. Therefore, when the tension release cam 35 is rotated by the tension release handle 36, the first
The sprocket 39 also rotates, and this first sprocket 39
Is transmitted to the second sprocket 41 via the bead chain 42, and the second sprocket 41 rotates. Further, the rotation of the second sprocket 41 causes the tension release cam 35 to rotate synchronously.

Further, the edge guide 27 has a connecting portion 27a.
Is provided, and the tip of the connecting portion 27a is bent to form an engaging portion 27b. As shown in the figure, the engaging portion 27b is always engaged with the cam surface 40a of the edge guide pressing force releasing cam 40. The other components of this embodiment are the same as the components described above.

In this embodiment having such a configuration, the state shown in FIG. 4A is a state in which the belt tension is applied to the conveyor belt 7 by the driven roller 10. From this belt tension applied state, in order to release the belt tension, the tension release handle 36 is operated to rotate the tension release cam 35. As a result, the tension releasing cam 35 moves the releasing force transmitting members 37, 37 in the direction opposite to the transfer sheet conveying direction, and the slide housing 30, the supporting member 28, and the driven roller 10 are all springed as in the above-described embodiment. It is moved in the opposite direction against the spring force of 34. As a result, the belt tension applied to the conveyor belt 7 is released, and the conveyor belt 7 changes from a taut state to a bent state.

When the tension releasing cam 35 rotates during the belt tension releasing operation, the second sprocket 41 also rotates in the same direction via the rotating shaft 35a. The rotation of the second sprocket 41 is transmitted to the first sprocket 39 via the bead chain 42, and the first sprocket 39 rotates. The rotation of the first sprocket 39 causes the edge guide pressing force releasing cam 40 to rotate synchronously, and the cam surface 40
The engaging portion 27b of the connecting portion 27a is pressed downward by a. Therefore, the engaging portion 27b moves downward, and the edge guide 27 also moves downward. When the belt tension is completely released from the conveyor belt 7 as shown in FIG. 7B, the edge guide 27 is completely separated from the conveyor belt 10 and the tension release handle 36 is at that position. By locking, this separated state is maintained.

Therefore, the first and second sprockets 3
9, 41, the bead chain 42 and the edge guide pressing force releasing cam 40 constitute the belt tension releasing operation interlocking means of the present invention. Moreover, the edge guide pressing force release cam 40 also serves as an edge guide holding member that holds the edge guide 27 in a state of being separated from the conveyor belt 7.

As described above, in this embodiment, the conveyor belt 10 is used.
The edge guide pressing force is automatically released in conjunction with the belt tension releasing operation of.

Although FIG. 4 shows only the left side, this embodiment is provided with the same edge guide pressing force releasing cam 40, the first and second sprockets 40 and 41, and the bead chain 42 on the right side as well. And tension release cam 3
The edge guide pressing force releasing cam 40 rotates when the belt 5 is rotated in the belt tension releasing direction, so that the right edge guide 27 is held in a state of being completely separated from the conveying belt 10.

FIG. 5 is a diagram showing still another embodiment of the present invention. In contrast to the embodiment shown in FIG. 4 described above, in this embodiment, as shown in FIG. 5A, an edge guide pressing force releasing cam 40 is fixedly mounted on the rotary shaft 35a of the tension releasing cam 35. Therefore, in the embodiment shown in FIG.
The first and second sprockets 40, 41 and the bead chain 42 are omitted, and the overall structure is simple.

In the present embodiment having the above-described structure, the belt tension is applied to the conveyor belt 7 shown in FIG.
When the tension release handle 36 is operated to rotate the tension release cam 35 in order to release the belt tension of the conveyor belt 7 from the state of pressing, the same operation is performed as shown in FIG. The roller 10 moves in the direction opposite to the transfer paper transport direction, and the belt tension of the transport belt 7 is released. At the same time, the edge guide pressing force releasing cam 40 rotates, and the cam surface 40a moves the edge guide 27 downward, so that the edge guide pressing force releasing cam 40 moves the side edge 7 of the conveyor belt 7.
Separate from a. Therefore, in this embodiment as well, as in the embodiment shown in FIG. 4, the edge guide pressing force is automatically released in association with the belt tension releasing operation of the conveyor belt 10.

FIG. 6 is a diagram showing still another embodiment of the present invention. In each of the embodiments shown in FIGS. 4 and 5 described above, the edge guide pressing force releasing cam 40 is used to release the pressing force of the edge guide 27, but in the present embodiment,
Instead of the edge guide pressing force releasing cam 40, as shown in FIG.
As shown in (a), the edge guide pressing force release guide 43
Is provided. The edge guide pressing force release guide 43 has an inclined guide portion 43a and a holding portion 43b formed continuously with the inclined guide portion 43a, and is fixed to the frame of the machine.

Although the belt tension imparting device and the belt tension releasing device shown in FIGS. 2, 4 and 5 are not shown in FIG. 6, these belt tension imparting device and belt tension releasing device are the same. It is provided.

In order to release the tension of the conveyor belt 7, the tension releasing handle is operated in the same manner to rotate the tension releasing cam to move the driven roller 10 in the direction opposite to the belt tension applying direction. The tension of the belt 7 is released. At the same time, when the driven roller 10 moves in the opposite direction, the guide contact portion 27c of the edge guide 27 contacts the inclined guide portion 43a of the edge guide pressing force release guide 43.

When the driven roller 10 further moves in the reverse direction in this state, the guide contact portion 27 is moved together with the reverse movement.
c is guided by the inclined guide portion 43a and moves downward.
As a result, the edge guide 27 moves downward and the conveyor belt 7
Away from the side edge 7a. At the belt tension release final position of the driven roller 10, the guide contact portion 27c is held by the holding portion 43b as shown in FIG. As a result, the edge guide 27 moves the side edge 7 a of the conveyor belt 7.
Will be kept completely separated from. Therefore, the edge guide pressing force releasing guide 43 constitutes the belt tension releasing operation interlocking means of the present invention and also functions as the edge guide holding member.

As described above, also in this embodiment, the edge guide pressing force is automatically released in association with the belt tension releasing operation of the conveyor belt 10 as in the respective embodiments shown in FIGS. 4 and 5. Will be done.

FIG. 7 is a diagram showing still another embodiment of the present invention. In each of the embodiments shown in FIGS. 4, 5 and 6, the edge guide pressing force is automatically released in association with the belt tension releasing operation of the conveyor belt 7. However, in the present embodiment, 3, the edge guide pressing force is manually released independently of the belt tension releasing operation of the conveyor belt 7.

That is, specifically, an edge guide pressing force releasing member 44 for releasing the edge guide pressing force is provided. This edge guide pressing force releasing member 44
Has its shaft portion 44a erected on the left and right frames 31, 31 so as to be movable in the axial direction and rotatable, and the lever portion 4a is provided on the shaft portion 44a outside the left frame 31.
5 are provided. One end 45a of the lever 45 is engageable with the engaging portion 27d of the left edge guide 27 in a direction in which the left edge guide 27 is separated from the transport belt 7 in the axial direction. Also, the other end 45b of the lever 45
Is provided at a position where it does not come into contact with the stopper 46 protruding from the left frame 31 in the rotational direction in the illustrated state. Further, an operation handle 44b is provided at the left end of the shaft portion 44a.

On the other hand, on the outer surface of the right frame 31,
A lever 47 for lever-like force transmission is provided.
One end 47a of the rotary lever 47 is engaged with the engaging portion 27d of the right edge guide 27, and the right edge guide 2 in the axial direction.
7 can be engaged in a direction away from the conveyor belt 7. The other end 47b side of the rotary lever 47 is provided with a compression spring 48.
Therefore, the rotary lever 47 is constantly urged in the counterclockwise direction, that is, in the direction in which one end 47a of the rotary lever 47 is separated from the engaging portion 27d of the right edge guide 27. There is.

Further, the other end 47b side of the rotary lever 47 is penetrated by the other end side of the shaft portion 44a, and the other end thereof has a rotary lever operating portion 44c for rotating the rotary lever 47 in the clockwise direction. Is provided.

In the present embodiment thus constructed, after the belt tension is released from the conveyor belt 7, the operation handle 44b is operated to show the edge guide pressing force releasing member 44 by a chain double-dashed line in FIG. Axial move left to position. As a result, the lever 45 moves the engaging portion 27.
The edge guide 27 on the left side is moved leftward via d to the position indicated by the chain double-dashed line. At the same time, the rotary lever actuating portion 44c of the edge guide pressing force releasing member 44 rotates the rotary lever 47 in the clockwise direction, so that the rotary lever 47 engages with the engaging portion 2.
The right edge guide 27 is moved to the right via 7d. Thus, the left and right edge guides 27 are separated from the left and right side edges of the conveyor belt.

Then, the edge guide pressing force releasing member 44
Is moved in the axial direction to the position indicated by the chain double-dashed line, and then the operation handle 44b is rotated to bring the other end 45b of the lever 45 into contact with the tip of the stopper 46. In this state, the spring 4
The edge guide pressing force releasing member 44 tries to move to the right by the spring force of 8. However, since the other end 45b of the lever 45 is in contact with the tip of the stopper 46, the edge guide pressing force releasing member 44 is moved to the right side. Is prevented from moving to. As a result, the edge guide pressing force releasing member 44 is held at the position indicated by the chain double-dashed line point, and therefore the left and right edge guides 2
7 is held in a state of being completely separated from the left and right side edges of the conveyor belt 7, respectively. The lever 45, the rotation lever 47, and the edge guide pressing force releasing member 44 constitute the left and right edge guide holding member interlocking means of the present invention.

As described above, in each of the above-mentioned embodiments,
When the belt tension is released from the conveyor belt 7, the edge guide 27 is separated from the side edge 7a of the conveyor belt 7. Therefore, the spring force of the spring 29 causes the edge guide 27 to move.
It is not added to the conveyor belt 7 via. Therefore, the side edge 7a of the conveyor belt 7 is prevented from buckling, and the durability of the conveyor belt 7 is improved.

In each of the above-described embodiments, the case where the present invention is applied to the sheet conveying belt of the tandem type color copying machine has been described, but the present invention is not limited to this and, for example, a belt. It can also be applied to other conveyor belts such as a photoconductor, an intermediate transfer member, and continuous paper.

[0066]

As is apparent from the above description, according to the endless belt conveying device in the image forming apparatus of the present invention,
When the belt tension release device releases the belt tension from the conveyor belt, the edge guide holding member keeps the edge guides apart from the side edges of the conveyor belt. It becomes possible to prevent the spring force of the spring pressing the edge guide from being applied. As a result, the buckling of the conveyor belt can be reliably prevented, so that the durability of the conveyor belt is improved and the life of the conveyor belt can be extended.

In particular, according to the invention of claim 2, in addition to these effects, when the belt tension is released from the conveyor belt, the edge guide is automatically separated from the side edge of the conveyor belt. It is possible to prevent forgetting to release the spring force of the edge guide applied to the conveyor belt, and to reliably protect the conveyor belt with one simple operation.

[Brief description of drawings]

FIG. 1 is a tandem-type digital color copying machine to which an embodiment of an endless belt conveying device in an image forming apparatus of the present invention is applied. It is a figure which shows a device roughly.

FIG. 2 is a partially enlarged perspective view of a belt tension applying device and a belt tension releasing device of the embodiment shown in FIG.

FIG. 3 is a partially enlarged sectional view showing an embodiment of the present invention.

FIG. 4 shows another embodiment of the present invention, FIG. 4A is a view showing a state in which an edge guide is in contact with a side edge of a conveyor belt,
FIG. 6B is a diagram showing a state in which the edge guide is separated from the side edge of the conveyor belt.

5A and 5B show still another embodiment of the present invention, FIG. 5A is a view showing a state where the edge guide is in contact with a side edge of the conveyor belt, and FIG. 5B is a side edge of the conveyor belt. It is a figure which shows the state spaced apart from.

6A and 6B show still another embodiment of the present invention, FIG. 6A is a view showing a state where the edge guide is in contact with a side edge of the conveyor belt, and FIG. 6B is a side edge of the conveyor belt. It is a figure which shows the state spaced apart from.

FIG. 7 is a diagram showing still another embodiment of the present invention.

FIG. 8 is a diagram showing a compliant edge guide according to the prior application.

FIG. 9: With this compliant edge guide,
It is a figure explaining that a conveyance belt is considered to cause buckling.

[Explanation of symbols]

1 ... Digital color copier, 2Y, 2M, 2C, 2K ... Photosensitive drum, 3Y, 3M, 3C, 3K ... Primary charger, 4Y, 4M, 4C, 4K ... Exposure device, 5Y, 5M, 5C, 5K ... Developing device, 6 ... Transfer device, 7 ... Conveyor belt, 8Y, 8M, 8C, 8K ... Transfer charger, 9 ... Drive roller, 10 ... Follower roller, 27 ... Edge guide, 29 ... Spring for urging edge guide , 31, 32 ... Frame, 3
4 ... Spring for applying belt tension, 35 ... Belt tension release cam, 36 ... Tension release handle, 38 ... Edge guide holding member, 39 ... First sprocket, 40 ... Edge guide pressing force release cam, 40a ... Cam surface, 41 ... second sprocket, 42 ... bead chain, 43 ... edge guide pressing force release guide, 44 ... edge guide pressing force release member, 45 ... lever, 46 ... stopper, 47 ... rotating lever, 48 ... spring

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Susumu Kobayashi 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (8)

[Claims] 1. An endless conveyor belt which is stretched around a plurality of rollers and conveys a transfer material in one direction; and at least one roller of the plurality of rollers, which applies belt tension to the conveyor belt. Endless belt conveyance in an image forming apparatus including at least a belt tension imparting roller, a tension imparting device that imparts a belt tension to the belt tension imparting roller, and a belt tension releasing device that releases the belt tension from the conveying belt. In the device, at least one roller of the plurality of rollers, an edge guide that is provided so as to be capable of separating from and contacting a side edge of the conveyor belt, and an edge guide that guides the side edge of the conveyor belt, and the edge guide An edge guide device including a spring that abuts the side edge of the conveyor belt with a predetermined force is provided, and the edge guide device is provided. An endless belt conveyor device in the image forming apparatus characterized by edge guide holding member for holding the guide in a state spaced from the side edge of the conveyor belt. 2. An endless conveyor belt which is stretched around a plurality of rollers and conveys a transfer material in one direction, and at least one roller of the plurality of rollers, which applies belt tension to the conveyor belt. Endless belt in an image forming apparatus including at least a belt tension applying roller, a belt tension applying device for applying a belt tension to the belt tension applying roller, and a belt tension releasing device for releasing the belt tension from the conveyor belt. In the conveyor, the belt tension imparting roller is provided with an edge guide for guiding the side edge of the conveyor belt, which is provided so as to be separable from the side edge of the conveyor belt, and a predetermined force is applied to the edge guide. Is provided with an edge guide device consisting of a spring that comes into contact with the side edge of the conveyor belt, and An edge guide holding member for holding the conveyance belt in a state of being separated from the side edge of the conveyance belt is provided, and further, in association with the belt tension releasing operation of the belt tension releasing device, the edge guide is separated from the side edge of the conveyance belt. An endless belt conveying device in an image forming apparatus, comprising a belt tension releasing operation interlocking means for operating the edge guide holding member so as to hold the edge guide holding member in a separated state. 3. The belt tension releasing operation interlocking means is provided with an edge guide pressing force releasing cam, and the edge guide pressing force releasing cam also serves as the edge guide holding member. Endless belt conveying device in the image forming apparatus. 4. The edge guide holding member is provided at each of left and right ends of the roller, and left and right edge guide holding member interlocking means for interlocking the left and right edge guide holding members are provided. The endless belt conveying device in the image forming apparatus according to any one of claims 1 to 3. 5. The endless belt conveying device in an image forming apparatus according to claim 1, wherein the endless belt is a photosensitive belt. 6. The endless belt conveying device in an image forming apparatus according to claim 1, wherein the endless belt is an intermediate belt. 7. The endless belt conveying device in an image forming apparatus according to claim 1, wherein the endless belt is a transfer belt. 8. The endless belt conveying device in an image forming apparatus according to claim 1, wherein the endless belt is continuous paper.