JPH0611001A - Belt driving device - Google Patents

Abstract

PURPOSE:To enhance assembling/dissembling workability in a belt driving device capable of automatically detecting and correcting deviated movement. CONSTITUTION:A transfer belt 5 is stretched across first through fourth rollers 1-4 in a freely traveling manner. A deviated movement detecting member 26 is disposed at the shaft end of the fourth roller 4. When the transfer belt 5 is deviated to be brought into contact with the deviated movement detecting member 26, one shaft end of the fourth roller 4 is shifted by the use of rotating torque of the deviated movement detecting member 26 so that the initial deviated movement can be eliminated. The deviated movement detecting member 26 and a tension unit 12 for applying a predetermined belt tension to the transfer belt 5 are fixed to the inside and outside of a frame 7, respectively. Fixing workability and maintenance workability are enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt driving device, and more particularly to a belt driving device provided with a mechanism for correcting deviation by displacing a shaft end portion of a roller when deviation occurs in a belt.

[0002]

2. Description of the Related Art Conventionally, in, for example, an electrophotographic apparatus or an electronic printer apparatus, flat belts having a dielectric layer or a photosensitive layer on the surface thereof are arranged in parallel with each other for the purpose of reducing the weight and size of the apparatus. It is known that the flat belt is used as a transfer belt or a photosensitive belt instead of the transfer drum or the photosensitive drum by being wound around a plurality of rollers.

In such an apparatus, high precision and high resolution are required to form an accurate image. However, when the flat belt is deviated in the width direction when the flat belt is running, accurate image formation cannot be performed and the performance is significantly deteriorated. Therefore, conventionally, various structures have been proposed as a structure for suppressing this deviation. As one example thereof, as shown in JP-A-56-127501, one in which the flat belt is forcibly prevented from eccentricity, and the one in Japanese Utility Model Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. 110609, when the deviation of the flat belt is detected by a belt position sensor and the deviation of the flat belt is detected, the shaft end portion of one roller is moved in accordance with the deviation amount. For example, the displacement is corrected to correct the deviation.

[0004]

However, the conventional structure as described above has a problem in practical use. That is, in the case where the deviation of the flat belt is forcibly prevented, it is necessary to increase the strength of the flat belt so as not to damage the flat belt, and a belt having a small thickness cannot be used. In addition, in the case where the deviation is detected by the belt position sensor, the complicated mechanism is used to detect and correct the deviation, which requires an expensive and extra space, which leads to an increase in the size of the entire apparatus. Will be connected.

In order to solve these problems, the inventor of the present invention is improving the structure of a belt drive device capable of automatically detecting and correcting the deviation. Specifically, one of the plurality of rollers is used as a deviation adjusting roller, and one side of the deviation adjusting roller is provided with a deviation detecting member that is rotatable independently of the deviation adjusting roller. . Then, the flat belt is configured to be biased in advance toward the bias detection member. And
When the flat belt travels and the flat belt comes into contact with the deviation detecting member due to the deviation, the contact causes the deviation detecting member to rotate, and this rotational force moves the shaft end portion of the deviation adjusting roller. A configuration is being developed in which the flat belt is given a deviation component in the direction opposite to the deviation by converting it into a force to correct the deviation.

Further, the inventor of the present invention has considered a case where such a mechanism capable of automatically correcting the deviation of the flat belt is installed in a color copying machine or the like having a complicated internal structure. We are developing for practical use. And
Since this color copying machine has a complicated internal structure, there is a concern that the entire apparatus may become large. If such an apparatus is incorporated with the automatic deviation correcting mechanism as described above, There is a risk of increasing the size of the entire device. Further, as the internal structure becomes complicated, there is a possibility that the assembling work of the device becomes complicated, and the disassembling and maintenance work at the time of maintenance becomes complicated. For this reason, it is a necessary requirement for the above-described automatic deviation correcting mechanism to make these operations as easy as possible when incorporated in a device having a complicated internal structure.

The present invention has been made in view of this point, and a belt drive device capable of automatically detecting and correcting a deviation causes an increase in size of the entire device by the belt drive device. It is an object of the present invention to obtain a structure that does not significantly deteriorate workability during assembly and maintenance without any trouble.

[0008]

In order to achieve this object, the present invention unitizes means for applying tension to at least a flat belt among functional parts of a belt driving device, and assembles it into a frame member. I put it on. Specifically, the means taken by the invention of claim 1 is a flat belt,
A plurality of rollers, each of which is configured as a deviation adjusting roller, is provided around the flat belt, and one shaft end portion of the deviation adjusting roller is independent of the deviation adjusting roller. And rotatably supported eccentricity detection member, eccentricity imparting means for moving the flat belt toward the arranging position of the eccentricity detection member, and the eccentricity impartment member that is linked to the eccentricity detection member. The flat belt is eccentrically moved by the means, and when the eccentricity detection member comes into contact with the flat belt and rotational torque acts, the rotational movement of the flat belt is caused by the axial end portion of the deviation adjusting roller in a predetermined direction. Roller end displacement means for converting the flat belt into a movement away from the deviation detecting member, and a shaft of the deviation adjusting roller on the side where the deviation detecting member is arranged. The frame material through which the end is inserted, and the deviation A shaft end supporting member that supports a shaft end of the leveling roller on the side where the deviation detecting member is disposed, and the shaft end supporting member is orthogonal to the axis line of the deviation adjusting roller. A belt tension imparting member that imparts a predetermined belt tension to the flat belt by increasing the distance between the axis line of the deviation adjusting roller and the axis line of at least one other roller by giving a biasing force in the direction. Be prepared. Further, the shaft end portion supporting member and the belt tension applying member are arranged on the side opposite to the arrangement position of the deviation adjusting roller with respect to the arrangement position of the frame member.

According to a second aspect of the present invention, in the belt driving device according to the first aspect, the shaft end supporting member is supported by a shaft end supporting base material, and the shaft end supporting member is supported by the shaft end supporting member. The relative movement of the axis of the deviation adjusting roller and the axis of at least one other roller relative to the base material is made to be large. A belt tension applying member is installed between the shaft end supporting member and the shaft end supporting base material, and the shaft end supporting base material is fastened to a frame member.

According to a third aspect of the present invention, in the belt driving device according to the first or second aspect, a back tension member is arranged on the shaft end supporting member. Then, the shaft end of the deviation adjusting roller on the side where the deviation detecting member is disposed is inserted into the back tension member and extends along the displacement direction of the shaft end by the roller end displacing means. A slide hole that is an elongated hole and a shaft insertion hole that extends in the extension direction of the slide hole and has one end opened to the slide hole and the other end opened to one end surface of the back tension member are formed. Further, a back tension shaft is inserted into the shaft insertion hole, the front end of which faces the inside of the slide hole, and the front end of which is abuttable with the shaft end of the deviation adjusting roller. The opening portion of the shaft insertion hole formed in the above is closed by a stop plate, while the back tension spring is housed in a compressed state between the back tension shaft and the stop plate.

The invention according to claim 4 is the same as claim 1, 2 or 3.
Alternatively, in the belt drive device according to the third aspect, the flat belt is biased by the offset imparting means to the roller end displacement means,
When the flat belt comes into contact with the deviation detecting member and a rotational torque acts on the deviation detecting member, the shaft of the deviation adjusting roller is displaced in a predetermined direction by being wound around the deviation detecting member due to its rotational movement. A shaft end displacement belt is provided. Then, the shaft end portion displacement belt is formed of a flexible belt-like body which is provided between the deviation detecting member and the shaft end portion supporting member.

[0012]

With the above construction, the present invention provides the following actions. According to the first aspect of the present invention, when the flat belt is biased by the action of the offset imparting means and comes into contact with the deviation detection member, the deviation detection member rotates due to contact friction with the flat belt. Then, along with this rotational movement, the rotational movement is converted into movement in which the shaft end portion of the deviation adjusting roller is displaced in a predetermined direction. When the shaft end portion of the deviation adjusting roller is displaced in this manner, the flat belt undergoes an eccentric displacement opposite to the eccentric direction, so that the initial eccentricity is corrected. That is, the displacement amount of the shaft end portion of the deviation adjusting roller according to the initial deviation is automatically given to correct the deviation of the flat belt. Therefore, the flat belt can travel stably, and particularly when the belt driving device is applied to an electrophotographic device or an electronic printer device, an accurate image (character) can be formed. At the time of assembling the belt driving device, the shaft end portion supporting member and the belt tension applying member are assembled to the frame member from the side opposite to the position where the deviation adjusting roller is arranged. On the other hand, in the disassembly work at the time of maintenance, conversely, the shaft end portion supporting member and the belt tension applying member are removed from the side opposite to the position where the deviation adjusting roller is arranged with respect to the frame material. Therefore, these operations can be performed simply and quickly. Further, by arranging the means for applying tension to the flat belt outside the frame member, this means is unitized.

According to the second aspect of the present invention, since the shaft end portion supporting member is assembled to the frame member through the shaft end portion supporting base material, the shaft end portion is disassembled during the disassembling work of the apparatus. The shaft end support member can be removed from the frame material simply by releasing the fastening state of the support base material to the frame material, and the work of removing the shaft end support member and the belt tension applying member from the frame material is further simplified. To be done. Also,
In this structure, if an opening having a diameter larger than that of the deviation adjusting roller and the deviation detecting member is formed in the frame member, the shaft end supporting member can be removed from the shaft end supporting member at the same time when the shaft end supporting member is removed. It is also possible to take out the deviation adjusting roller and the deviation detecting member which are connected to each other so as to be pulled out by passing through the opening.

According to the third aspect of the invention, when the shaft end portion of the deviation adjusting roller is displaced in the predetermined direction by the operation of the roller end portion displacement means, the back tension spring causes the shaft end portion to move with respect to the shaft end portion. A biasing force in the opposite direction to the displacement direction is given, and this displacement amount is set appropriately. And since the means for giving this biasing force is unitized by the back tension member,
It is possible to simplify the assembling and disassembling work to the device and reduce the installation space.

In the invention according to claim 4, the shaft end portion displacement belt wound around the deviation detecting member in the deviation correcting operation is formed of a flexible belt-like member. The winding operation is surely performed. Further, since one end of the shaft end portion displacement belt is attached to the shaft end portion supporting member, the disposition state thereof can be improved by the biasing force of the belt tension applying member provided to the shaft end portion supporting member. Therefore, the winding operation can be performed smoothly.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, the case where the belt driving device according to the present invention is installed in an electrophotographic apparatus, particularly a color copying machine will be described.

FIG. 1 and FIG. 2 show a belt drive device of a four-axis system housed in a color copying machine according to this embodiment.
In FIGS. 1 and 2, reference numerals 1, 2, 3, and 4 denote first, second, third, and fourth rollers, respectively. Each roller 1,
2, 3 and 4 are shaft members 1a, 2a, 3a and 4a,
A tubular body 1b made of rubber or the like, which is concentric with the shaft members 1a, 2a, 3a, 4a and has a slightly larger diameter than the left and right ends of the shaft members 1a, 2a, 3a, 4a, 2b, 3
b and 4b. This tubular body 1b, 2b, 3
As the material of b and 4b, for example, EPDM crosslinked rubber is adopted. However, these cylindrical bodies 1b, 2b, 3b, 4
b may not be an elastic material such as resin or aluminum.

A transfer belt 5 as a flat belt according to the present invention, which is formed by forming a dielectric layer on the surface of a base material, is movably wound around each of the rollers 1, 2, 3, and 4. There is. Therefore, in the present belt driving device, the transfer belt 5 functions as a dielectric of the electrophotographic device. Further, as the base material of the transfer belt 5, for example, biaxially stretched polyester is adopted, and the tensile elastic modulus is set to 200 kg / mm ² or more.

The shaft member 1a of the first roller 1 is connected to the drive shaft of a drive motor (not shown) so that the drive force of the drive motor can be transmitted. That is, the first roller 1 functions as a driving roller.

The second roller 3 and the third roller 3 are driven rollers, the outer diameter of which is set smaller than that of the first roller 1, and the axis thereof is the axis of the first roller 1. It is arranged in parallel with.

The fourth roller 4 is a deviation adjusting roller according to the present invention, and its axis is the same as the second roller 3 and the third roller 3 in the state shown in FIGS. It is arranged parallel to the axis of the first roller 1.

As shown in FIG. 1, the left and right shaft ends of the rollers 1, 2, 3 and 4 are supported by frames 6 and 7, respectively. Of the frames 6 and 7, the first frame 6 arranged on the left side in FIG. 1 is a plate material formed in a substantially trapezoidal shape as shown in FIGS. In the vicinity of the part, the above-mentioned rollers 1,
The left shaft ends of 2, 3, 4 are inserted, and support holes 6a, 6b, 6c, 6d for supporting the shaft ends are opened.
Of the support holes 6a, 6b, 6c, 6d, the first to first
Support holes 6a for supporting the shaft ends of the third rollers 1, 2, 3
Reference numerals 6b and 6c are circular openings corresponding to the outer diameters of the shaft ends of the rollers 1, 2 and 3, and support the shaft ends so that they are rotatable and cannot be displaced. There is. On the other hand, the support hole for supporting the shaft end portion of the fourth roller 4 is formed by a long hole 6d. The extending direction of the elongated hole 6d is set to be a direction orthogonal to the tangent line at the contact position of the transfer belt 5 on the outer peripheral surface of the fourth roller 4, and the shaft end portion of the fourth roller 4 is in this direction. It is said that it can be displaced and moved. Therefore, the belt tension is increased when the fourth roller 4 moves outward (direction of arrow A in FIG. 3) along the elongated hole 6d. A spring locking piece 6e is provided at the outer edge of the first frame 6 in the extending direction of the elongated hole 6d and is bent outward in the axial direction of the roller. Further, a small-diameter opening 6f is formed in the first frame 6 in the vicinity of the inner end in the extension direction of the elongated hole 6d, and the opening 6f is formed with respect to the outer surface of the first frame 6. A guide pin 8 protruding vertically is attached.

The first frame 6 has a first frame on the outer side.
A tension plate 9 is arranged. The first tension plate 9 has a circular support hole 9a for inserting and supporting the shaft end portion of the fourth roller 4, and the opening 9a is provided with the fourth roller 4 of the fourth roller 4 inserted into the elongated hole 6d. The shaft end on the left side is inserted, and the E-ring R1 is attached to the shaft end from the outside thereof so that the shaft end of the fourth roller 4 is the first end.
It is rotatably supported by the tension plate 9. Also, this first tension plate 9
A spring locking piece 9b is provided at one end edge in the longitudinal direction thereof and is bent outward in the axial direction of the roller. Further, in the lower side position of the spring locking piece 9b in the first tension plate 9, the first tension plate 9 is attached to the first frame 6 in the same direction as the extension direction of the elongated hole 6d. A slide groove 9c is formed by notching in a U-shape that extends, and the slide groove 9c is externally fitted to the guide pin 8, and the first tension plate 9 has the slide groove 9c. While being guided by 8, it is movable in the extension direction of the elongated hole 6d together with the shaft end portion of the fourth roller 4.

A first tension spring 10 is erected in a stretched state between the spring locking piece 6e of the first frame 6 and the spring locking piece 9b of the first tension plate 9. The urging force of the first tension spring 10 is applied to the first tension plate 9 in the direction of arrow A in FIG. The direction of this urging force is a direction in which the fourth roller 4 is displaced outward along the extension direction of the elongated hole 6d, that is, the axis of the fourth roller 4 and the axes of the other rollers 1, 2 and 3. Since the distance is increased, a predetermined belt tension is applied to the transfer belt 5.

On the other hand, the second frame 7 disposed on the right side in FIG. 1 is a plate material formed in a substantially rectangular shape as the frame material in the present invention, and as shown in FIGS. 2 and 6, Support holes 7a, 7b for inserting and supporting the right shaft ends of the first roller 1 and the second roller 2 at the lower edge thereof.
Is opened, and a support hole 7c for inserting and supporting the right shaft end of the third roller 3 is opened at the upper end edge. The support holes 7a, 7b and 7c are circular openings corresponding to the outer diameters of the shaft ends of the rollers 1, 2 and 3, and the shaft ends are rotatable and can be displaced. Supports impossible. On the other hand, at a position corresponding to the shaft end of the fourth roller 4, a relatively large diameter larger than the outer diameter of the fourth roller 4 and larger than the outer diameter of the deviation detecting member 26 described later. An opening 7d having a shape is formed. Further, a plurality of flanges 7e, 7e, ... Are integrally formed on the outer edge of the second frame 7, and these flanges 7e are shown in FIGS.
As shown in FIG. 3, it is attached to the casing 20 of the electrophotographic apparatus. Further, screw holes 7f, 7f, ... For assembling a tension unit 12, which will be described later, are formed at four locations around the opening 7d.

In the belt drive device of this embodiment, the tension unit 12 is assembled from the outside and the roller unit 13 is assembled from the inside to the opening 7d of the second frame 7. Hereafter, each unit 1
The configurations of 2 and 13 will be described.

First, the tension unit 12 will be described. As shown in FIG. 5, this tension unit 1
2 includes a frame plate 14, a second tension plate 15, and a tension slider 16. The frame plate 14 has a substantially rectangular opening 14a formed in the center thereof, which is slightly larger than the shape of the tension slider 16. Further, screw holes 14b, 14b, through which screws S, S, ... (See FIG. 6) are inserted at four corners of the frame plate 14 when screwed to the second frame 7. ... is formed.
Further, caulking holes 14c14c, ... For caulking the pins P, P, ... When caulking and supporting the second tension plate 15 to the frame plate 14 are formed in the upper portion and the left and right side portions of the opening 14a. Further, a spring locking piece 14d is provided at the upper end of the front edge of the frame plate 14 in FIG. 5 and is bent outward along the roller axis direction.

On the other hand, the second tension plate 15 is attached to the outer side surface of the frame plate 14 as the shaft end supporting member in the present invention.
The caulking holes 14c, 14c of the frame plate 14,
The pin insertion holes 15a, 15 formed of elongated holes at positions corresponding to
are formed. And this pin insertion hole 15
The extension direction of a is set to the same direction as the extension direction of the elongated hole 6d in the first frame 6 described above, and the pin insertion holes 15a, 15a, ... And the caulking holes 14c, 14c ,.
The sliding ring 2 made of a self-lubricating material in which the pins P, P, ... Are inserted and the pin P is inserted between the frame plate 14 and the second tension plate 15.
When the pins P, P, ... Are crimped in a state where the pins 1, 2, ... Are arranged, the second tension plate 15 has the frame plate 14 and the second frame by the dimension in the longitudinal direction of the pin insertion hole 15a. It is possible to freely move relative to 7, and with this movement, the right end of the fourth roller 4 can be displaced and moved. In addition, a spring locking piece 15b is provided at an edge portion of the second tension plate 15 on the far side in FIG. 5 and is bent outward in the roller axial direction.

The second tension plate 15 has a long hole 15c for inserting and supporting the right shaft end of the fourth roller 4, and the frame plate 14 has an opening 15c. The right shaft end of the fourth roller 4 inserted through 14a is inserted, and the E-ring R2 (see FIG. 6) is attached to the shaft end from the outside thereof to rotate the shaft end of the fourth roller 4. It is designed to be freely supported. As a result, the above-mentioned second tension plate 15
The belt tension increases when the fourth roller 4 moves in the direction of arrow B in FIG. In addition, the spring locking piece 14d and the second
Spring locking piece 15 in tension plate 15
A second tension spring 17 as a belt tension imparting member according to the present invention is erected in a stretched state between b and b. The urging force of the second tension spring 17 causes the tension plate 14 to move the arrow in FIG. A biasing force in the B direction is applied. The direction of this urging force is a direction in which the fourth roller 4 is displaced outward through the second tension plate 15 along the extension direction of the pin insertion hole 15a, that is, the axis of the fourth roller 4 and others. Since the direction of increasing the distance from the axes of the rollers 1, 2 and 3 is set, a predetermined belt tension is applied to the transfer belt 5.

The tension springs 10 and 17 described above are set so that the left and right biasing forces are different. That is, the first frame attached to the first frame 6
The biasing force of the tension spring 10 is set to be larger than the biasing force of the second tension spring 16 attached to the second frame 7. As a result, the belt tension on the left side in FIG. 1 is configured to be higher than the belt tension on the right side.
The transfer belt 5 is configured to deviate in the direction of arrow C. By this, the bias application means in the present invention is configured.

The elongated hole 15c formed in the second tension plate 15 extends in a direction perpendicular to the elongated direction of the pin insertion hole 15a. The elongated hole 15c extends along the elongated hole 15c. Only the right shaft end of the fourth roller 4 can move in a direction substantially orthogonal to the roller shaft center direction (see arrow D in FIG. 2). 4 is the other three rollers 1,
It is configured to be inclined with respect to the second and third.

Further, a screw hole 15d for supporting the tension slider 16 is opened at the lower end of the second tension plate 15. A small-diameter opening 15e is formed in the central portion of the tension plate 15, and the locking pin 1 protruding vertically to the inner surface of the tension plate 14 is formed in the opening 15e.
8 is installed.

On the other hand, the tension slider 16 is a back tension member as referred to in the present invention, which is made of a lubricious engineering plastic material such as a polyastral resin or a nylon resin, and the second tension plate 15 is provided at the upper end thereof. Slot 15 formed in
A shaft end support portion 16a having a shape substantially matching the shape of c is formed, and a slide hole 16b is formed through the shaft end support portion 16a in a horizontal direction. A shaft insertion hole 16c is formed across the slide hole 16b and the lower end surface of the tension slider 16. Also,
An inner portion of the lower end portion of the tension slider 16 is formed with an extension 16d that extends slightly downward, and a screw hole 16e is formed in the center of the extension 16d.

Then, as shown in FIGS. 1 and 5, a back tension shaft 22 is inserted into the shaft insertion hole 16c of the tension slider 16. The back tension shaft 22 comes into contact with the outer peripheral surface of the shaft member 4a of the fourth roller 4 when the tip of the back tension shaft 22 faces the slide hole 16b. Also,
A large diameter portion 22a having an outer diameter dimension that substantially matches the inner diameter dimension of the shaft insertion hole 16c is formed at an intermediate portion of the back tension shaft 22 in its extension direction. A back tension spring 23 is inserted into the shaft insertion hole 16c from the back side of the back tension shaft 22, and the back tension spring 23 is brought into contact with the back surface of the large diameter portion 22a of the back tension shaft 22. It is like this. Further, a stop plate 24 is attached from the back side of the back tension spring 23. This stop plate 2
4 is a shaft insertion hole 16 of the tension slider 16
It is formed in a substantially L shape so as to face the lower end portion of c and the rear surface side of the extension portion 16d, and has a small diameter opening 24 at a position corresponding to the screw hole 16e formed in the extension portion 16d.
a is formed. Then, the tension slider 16
Back tension shaft 2 into the shaft insertion hole 16c of
2 and the back tension spring 23 are inserted, the shaft insertion hole 16c is closed by the stopper plate 24,
The opening 24a of the stop plate 24 and the screw hole 16 of the extension 16c
e and the set screw 25 is screwed over the screw hole 15d of the second tension plate 15. As a result, the back tension spring 23 is housed in a compressed state between the large diameter portion 22a of the back tension shaft 22 and the stop plate 24, and the back tension spring 23 is urged by the urging force of the back tension spring 23. The tip of the back tension shaft 22 presses the shaft member 4a of the fourth roller 4 in the direction of arrow E in FIG.
The lower end of 6 is supported by the second tension plate 15.

Next, the roller unit 13 will be described. The roller unit 13 is located at the right shaft end of the fourth roller 4 and inside the second frame 7, that is, the fourth unit.
It is arranged on the side where the roller 4 is arranged. Hereinafter, each part of the roller unit 13 will be described. 1 and 4
Further, as shown in FIG. 6, a deviation detecting member 26 is arranged at the inner side position of the second frame 7 at the right shaft end of the fourth roller 4. This deviation detection member 26 is
An insertion hole 26a having substantially the same diameter as that of the shaft member 4a of the fourth roller 4 is formed in the central portion thereof, and the shaft member 4a of the fourth roller 4 is inserted into the insertion hole 26a,
The shaft member 4a is supported so as to be rotatable coaxially with the fourth roller 4 and independently of the fourth roller 4. Further, this deviation detecting member 26 is
The belt material is made of urethane elastomer having a high friction coefficient and excellent wear resistance. The inside end surface of the deviation detecting member 26 is arranged close to the end surface of the cylindrical body 4b of the fourth roller 4 with a small gap. In addition, a thin cylindrical contact ring 4c is formed on the end surface of the cylindrical body 4b facing the inner end surface of the deviation detecting member 26.
Is embedded, and the end face of the contact ring 4c is brought into contact with the inner end face of the deviation detecting member 26, so that the deviation detecting member 26 and the cylindrical body 4b of the fourth roller 4 are directly contacted with each other. While avoiding this, the friction coefficient between the two is reduced and the position of the deviation detecting member 26 is regulated. Further, in the deviation detecting member 26, the outer diameter of the portion of the fourth roller 4 facing the end surface of the tubular body 4b is set to be the same as the outer diameter of the fourth roller 4, and from the end surface of the tubular body 4b. It has a riding surface 26b that is inclined in a taper shape, the diameter of which gradually increases with increasing distance. Then, when the transfer belt 5 is deviated in the direction of arrow C in FIG. 1, the deviation causes the end edge portion of the transfer belt 5 to ride on the riding surface 26b of the deviation detecting member 26. . Further, a boss portion 26c is formed on the outer end surface of the deviation detecting member 26.

A locking pin 27 is erected on the end face of the deviation detecting member 26 facing the tension unit 12. The locking pin 27 has the second
Locking pin 18 provided on the tension plate 15
It is formed in the same shape as.

Then, the second tension plate 15
A shaft end displacing belt 28 is stretched between a locking pin 18 provided on the lock pin 27 and a locking pin 27 provided on the deviation detecting member 26. This shaft end displacement belt 28
Is a flexible film-shaped band, and both ends thereof are wound to form hook portions 28a and 28b. The hook portions 28a and 28b are attached to the locking pins 18 and 27, respectively. In the locked state, a part of the shaft end displacement belt 28 is wound around the boss portion 26c of the deviation detecting member 26.

With such a structure, the transfer belt 5 is
When the transfer belt 5 rides on the riding surface 26b of the deviation detecting member 26 due to the deviation (direction of arrow C in FIG. 1) caused by the running of the deviation detecting member 26 and the rotational torque acts on the deviation detecting member 26, the deviation detecting member 26 Rotation of the shaft end displacement belt 28
Is wound around the boss portion 26c of the deviation detecting member 26, and the left shaft end of the fourth roller 4 is moved along the elongated hole 15c and separated from the shaft end of the third roller 3. Direction, that is, in the direction of arrow D in FIG. That is, the transfer belt 5 is wound along the circumferential direction of the fourth roller 4 with the fourth roller 4 tilted to the right toward the belt traveling direction, so that the transfer belt 5 is moved in the direction of arrow C in FIG. It is configured to move in the direction of arrow F, which is the opposite direction to the direction. This constitutes a roller end displacing means for displacing the shaft end of the fourth roller 4 in a direction orthogonal to the roller shaft center when a rotational torque acts on the deviation detecting member 26. That is,
When the left shaft end of the fourth roller 4 is displaced in the D direction,
A deviation component opposite to the initial deviation component (C direction component) is generated, and the shaft end portion of the fourth roller 4 is displaced until it cancels out with the initial deviation component.

Further, as described above, since the biasing force of the back tension spring 23 is applied to the shaft member 4a of the fourth roller 4 via the back tension shaft 22, the deviation detection of the transfer belt 5 is detected. When the riding operation on the member 26 is canceled, the left shaft end of the shaft member 4a of the fourth roller 4 is returned to a predetermined position (the position shown in FIGS. 1 and 2) by the urging force of the back tension spring 23. It is supposed to be. With such a configuration, when the deviation component in the reverse direction due to the displacement of the shaft end portion of the fourth roller 4 becomes larger than the initial deviation component, the transfer belt 5 starts the deviation in the opposite direction, and the deviation detection member 26. Since the riding amount of the roller on the riding surface 26b is reduced, the rotational torque of the deviation detecting member 26 is also reduced, and as a result, the back tension spring 23 also reduces the displacement amount of the shaft end portion of the fourth roller 4. ing.

The feature of this embodiment is the assembling work of this belt drive device or the disassembly and repair work at the time of maintenance. That is, as described above, in the belt driving device, the tension unit 12 is provided outside the second frame 7 and the roller unit 13 is provided inside the second frame 7, and the opening 7d of the second frame 7 is provided. The tension unit 12 is assembled from the outside and the roller unit 13 is assembled from the inside. Therefore, in this assembling work, first, as shown in FIG. 5, the tension unit 12 is assembled and unitized in advance as described above, and as shown in FIG. The frame 7 is screwed from the outside. That is, the frame plate 14 of the tension unit 12 is screwed to the outer surface of the second frame 7 with the screw S. After that, the deviation detecting member 26 is assembled to the shaft end portion of the fourth roller 4, and the E ring R3 is attached to the outer side position of the deviation detecting member 26 at the shaft end portion of the fourth roller 4 to remove the deviation detecting member 26. Regulate position. Then, the shaft end of the fourth roller 4 is inserted from the inside of the second frame 7 through the opening 7d of the second frame 7 and the slide hole 16b of the tension slider 16, and the E-ring is attached to the outside end thereof. Install R2. As a result, the shaft end of the fourth roller 4 penetrates through the second frame 7 and the tension unit 12
Has been assembled into. After that, each locking pin 1 of the second tension plate 15 and the deviation detection member 26
A shaft end displacement belt 28 is stretched over 8 and 27. On the other hand, at the left shaft end of the fourth roller 4, as shown in FIG. 7, the shaft end is inserted through the first frame 6 and the first tension plate 9 to be assembled. In this way, the assembling work of the left and right shaft ends of the fourth roller 4 to the respective frames 6 and 7 is completed, and the respective frames 6 and 7 are attached to the apparatus casing 20. And the work of assembling the peripheral members to the device is completed. As described above, the fourth roller 4 having a mechanism for applying a predetermined belt tension to the transfer belt 5 and a mechanism for automatically correcting the deviation of the transfer belt 5 can be assembled to the apparatus by such a simple assembling work. it can. That is, since each functional component is unitized and each is assembled from the inside and outside of the second frame 7, the assembling work can be easily performed.

On the other hand, when the tension unit 12 and the roller unit 13 are removed from the second frame 7 in the disassembling work at the time of maintenance, the fourth roller 4
The shaft end portion on the left side of the frame plate is removed from the first frame 6 and the first tension plate 9, and then the fastening state between the frame plate 14 and the second frame 7 is released on the shaft end portion side on the right side of the frame plate. 14 is removed from the second frame 7. As a result, this frame plate 14
Attached to the second tension plate 15 or the second tension plate
The tension spring 17 is removed from the second frame 7. At this time, since the right shaft end of the fourth roller 4 is still attached to the tension unit 12, the fourth roller 4 and the deviation detecting member 26.
Passes through the opening 7d of the second frame 7 from the inside toward the outside, and is pulled out integrally with the tension unit 12 and taken out. In this way, each of the units 12 and 13 and the fourth roller 4 can be easily taken out of the apparatus, so that these operations can be simplified and the operation time can be shortened. Further, this unitization can reduce the installation space of each functional component, and the belt driving device 1 can be downsized as a whole as the belt driving device 1 is downsized. Further, since one end of the shaft end portion displacement belt 28 is attached to the second tension plate 15 by the locking pin 18, the urging force of the second tension spring 17 provided to the second tension plate 15 The extended state can be ensured satisfactorily, and the winding operation around the boss portion 26c accompanying the rotation of the deviation detection member 26 is performed with good responsiveness.

Next, the operation of the belt driving device having the above structure will be described. First, when the transfer belt 5 is running, since the left and right belt tensions are different as described above, the transfer belt 5 always deviates in the C direction in FIG. That is, the transfer belt 5 is biased toward the deviation detection member 26 while running, and the transfer belt 5 is moved.
Of the transfer belt 5 due to the deviation of the
When riding on the riding surface 26b, the deviation detecting member 26 is rotated with respect to the shaft member 4a by the frictional force acting between the transfer belt 5 and the riding surface 26b of the deviation detecting member 26. Shaft end displacement belt 28
Will be wound up.

By winding the shaft end portion displacement belt 28, the shaft end portion of the fourth roller 4 on which the deviation detecting member 26 is arranged is displaced in the D direction. Due to this displacement, the transfer belt 5 travels while being wound in the direction opposite to the C direction, and the deviation of the transfer belt 5 in the C direction is limited. At the same time, due to the displacement of the shaft end portion, the back tension shaft 22 is moved in the direction of coming out of the slide hole 16a, and the back tension spring 23 is compressed and the spring reaction force also increases. The amount of displacement of the fourth roller 4 is regulated by the balance between the take-up force and the spring reaction force of the back tension spring 23, and the position of the end portion of the transfer belt 5 is maintained at a certain fixed position.

Since the transfer belt 5 travels in this manner, a large deviation of the transfer belt 5 can be prevented, and the deviation amount of the transfer belt 5 can be suppressed to, for example, ten and several μm. That is, while the transfer belt 5 is preliminarily deviated in one direction, the deviation is automatically corrected, so that the deviation amount can be made small and the transfer belt 5 can be stably run. Therefore, in the color copying machine as in this example, accurate image printing can be performed.

As described above, in the structure of this embodiment, each functional component is provided by the tension unit 12 and the roller unit 13 to the belt drive device which can automatically detect and correct the deviation. Since they are unitized and assembled from the inside and outside of the second frame 7, the belt driving device does not increase the size of the entire device, and the workability during assembly and maintenance is not deteriorated. Therefore, it is possible to improve the practicability when mounted on a color copying machine having a complicated internal mechanism.

In this example, the belt end displacement belt 2 of the belt-shaped body is used as a member for converting the rotational force of the deviation detecting member into the shaft end.
However, the present invention is not limited to this, and a string or the like may be adopted as long as it is a member that can be wound around the deviation detection member 26. Further, in this example, the driving device for the transfer belt 5 of the color copying machine has been described, but the present invention is not limited to this, and is similarly applied to a belt driving device of a printer device or a normal flat belt driving device. be able to. Further, the bias applying means is not limited to the one in which the left and right belt tensions are made different, but may be configured such that one of the rollers is arranged to be inclined to perform the initial deviation.

[0047]

As described above, according to the present invention,
The following effects are exhibited. According to the first aspect of the present invention, the shaft end portion supporting member and the belt tension applying member are arranged on the side opposite to the arrangement position of the deviation adjusting roller with respect to the arrangement position of the frame member, At the time of assembling the belt driving device, the shaft end portion supporting member and the belt tension applying member are assembled to the frame member from the side opposite to the position where the deviation adjusting roller is arranged, while at the time of maintenance. On the contrary, the disassembling work is simplified because the shaft end supporting member and the belt tension applying member are detached from the side opposite to the position where the deviation adjusting roller is arranged with respect to the frame member. Moreover, since the means for applying tension to the flat belt is arranged outside the frame member, the means can be unitized, and the overall size of the apparatus can be reduced. ,this It is possible to greatly improve the utility of the installation in complex equipment of the internal structure, such as for example a color copying machine of the belt driving device.

According to the second aspect of the present invention, the shaft end supporting member is supported on the shaft end supporting base material, and the shaft end supporting member is eccentrically adjusted with respect to the shaft end supporting base material. The axis of the roller for use and the axis of at least one other roller are allowed to move relative to each other in a direction in which the distance between them becomes large, and tension is applied between the shaft end supporting member and the shaft end supporting base material. The applying member is installed, and the shaft end supporting base material is fastened to the frame material by screwing, and the shaft end supporting member is assembled to the frame material via the shaft end supporting base material. Therefore, when disassembling the device, the shaft end support member can be removed from the frame material simply by releasing the fastening state of the shaft end support base material to the frame material. Removal of support member and tension applying member from frame material It is possible to further simplify the work. Further, in the present invention, as in the above-described embodiment,
If an opening having a diameter larger than that of the deviation adjusting roller and the deviation detecting member is formed in the frame member, the shaft end supporting member can be removed at the same time as the shaft end supporting member is removed. The deviation adjusting roller and the deviation detecting member may be taken out by passing through the opening.

According to the third aspect of the present invention, the back tension shaft and the back tension spring are accommodated in the shaft insertion hole of the back tension member, and the back tension shaft and the back tension spring are reversed with respect to the displacement of the shaft end portion by the roller end portion displacement means. Since the means for applying the biasing force in the direction is unitized, it is possible to simplify the assembling and disassembling work of this means to the device and reduce the installation space.

According to the fourth aspect of the present invention, since the shaft end portion displacement belt wound around the deviation detecting member in the deviation correcting operation is formed of a flexible belt-like member, the deviation detection is performed. The winding operation of the member is reliably performed, and since one end of the shaft end displacement belt is attached to the shaft end support member, the belt tension applying member applied to the shaft end support member. Due to the urging force due to, the arrangement state can be secured well, and the winding operation can be performed smoothly.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view in which a part of a belt driving device is broken.

FIG. 2 is a side view showing a supported state of a right shaft end portion in FIG.

FIG. 3 is a side view showing a supported state of a left shaft end portion in FIG.

FIG. 4 is a vertical cross-sectional front view showing a supporting state of a right shaft end portion in FIG.

FIG. 5 is a perspective view showing an assembly operation of the tension unit.

FIG. 6 is a perspective view showing an assembling operation of a tension unit and a roller unit.

FIG. 7 is a perspective view showing an assembling operation of a peripheral portion of the first frame.

[Explanation of symbols]

1 1st roller 2 2nd roller 3 3rd roller 4 4th roller (deviation adjustment roller) 5 Transfer belt (flat belt) 7 2nd frame (frame material) 14 Frame plate (shaft end support base material) 15 Second tension plate (shaft end support member) 16 Tension slider (back tension member) 16b Slide hole 16c Shaft insertion hole 17 Second tension spring (belt tension applying member) 22 Back tension shaft 23 Back tension spring 26 Deviation detecting member 28 Shaft end displacement belt

Claims (4)

[Claims] 1. A flat belt, a plurality of rollers around which the flat belt is stretched, at least one of which is a deviation adjusting roller, and one shaft end portion of the deviation adjusting roller, An eccentricity detection member rotatably supported independently of the eccentricity adjustment roller, an offset imparting means for moving the flat belt toward an arrangement position of the eccentricity detection member, and the eccentricity detection. When the flat belt is connected to the member, the flat belt is eccentrically moved by the offset imparting means, and the flat belt comes into contact with the deviation detection member due to the deviation and a rotational torque acts,
Roller end displacing means for converting the rotational movement into movement in which the shaft end of the deviation adjusting roller is displaced in a predetermined direction, and moving the flat belt in a direction away from the deviation detecting member; A frame member through which the shaft end portion of the adjustment roller on which the deviation detection member is disposed is inserted, and a shaft end portion of the deviation adjustment roller on the side where the deviation detection member is disposed. A shaft end supporting member to be supported, and a biasing force in a direction perpendicular to the axis line of the deviation adjusting roller is applied to the shaft end supporting member to at least the axis line of the deviation adjusting roller. A belt tension applying member for increasing the distance from the axis of one roller to apply a predetermined belt tension to the flat belt, wherein the shaft end supporting member and the belt tension applying member are the frame members. For eccentricity adjustment with respect to the installation position of A belt drive device, wherein the belt drive device is disposed on the side opposite to the position where the rollers are disposed. 2. The belt driving device according to claim 1, wherein the shaft end supporting member is supported by the shaft end supporting base, and the shaft end supporting member is relative to the shaft end supporting base. ,
The shaft of the deviation adjusting roller and the shaft of at least one other roller can be relatively moved in a direction in which the distance between the shaft and the shaft end supporting member is increased. A belt driving device, characterized in that a belt tension applying member is provided between the shaft end supporting member and the frame end member. 3. The belt driving device according to claim 1, wherein a back tension member is provided on the shaft end portion supporting member, and the back tension member has a deviation in a deviation adjusting roller. A slide hole which is an elongated hole into which the shaft end on the side where the detection member is disposed is inserted and which extends along the displacement direction of the shaft end by the roller end displacement means, and which extends in the extension direction of the slide hole. A shaft insertion hole having one end opened to the slide hole and the other end opened to one end surface of the back tension member, and the tip end of the shaft insertion hole faces the slide hole, A back tension shaft, the tip of which is brought into abutment with the shaft end of the deviation adjusting roller, is inserted, and the opening portion of the shaft insertion hole formed at one end surface of the back tension member is stopped. While it is closed by a belt drive, characterized in that the back tension spring is accommodated in a compressed state between the back tension shaft and stop plate. 4. The belt driving device according to claim 1, 2 or 3, wherein the roller end displacing means is configured such that the flat belt is biased by the biasing imparting means, and the flat belt comes into contact with the deviation detection member to rotate. A shaft end portion displacement belt is provided which displaces the shaft end portion of the deviation adjusting roller in a predetermined direction by being wound around the deviation detecting member due to its rotational movement when torque is applied. The belt driving device is characterized in that the shaft end portion displacement belt is formed of a flexible belt-like body which is provided between the deviation detecting member and the shaft end portion supporting member.