JP2000075698A - Belt type fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution and to accurately prevent a belt from meandering. SOLUTION: The shaft end parts 24 of a heating roller 5 where the belt 6 is wound round are supported by supporting members 45 and (73) through a bearing 26 consisting of polyamid-imido based resin. A meandering detection member 120 is supported by the end parts 24 so that they are mutually freely rotated. Then, a rolling contact part consisting of two projection parts is formed at a slide bearing 45 supported by one end part 24 and a rolling receiving part consisting of two recesses is formed at one supporting member 45. By the rolling receiving part, the rolling contact part is supported. When slight torque acts on the detection member 120 because the belt meanders and it is brought into contact with the belt contact part, the shaft end parts 24 are displaced. Thus, the belt is prevented from meandering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt fixing device and a belt meandering prevention device implemented in an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile machine.

[0002]

2. Description of the Related Art A typical prior art is disclosed in JP-A-9-907.
87. The belt fixing device heats and melts the toner image on the recording paper through a belt, then cools and peels off the toner from the belt. Because of the peeling, there is an excellent advantage that the offset phenomenon that the toner adheres to the belt hardly occurs. In a belt fixing device, a recording sheet having a toner image is sandwiched between belts for a relatively long distance, so-called fixing nip width is increased, and fixing quality is improved.

In one proposed belt fixing device, in order to prevent belt meandering, a tension roller for applying tension to the belt is devised to prevent meandering. In this belt fixing device, a means for preventing belt meandering is provided with a meandering detection member having a belt contact portion at the shaft end of the tension roller. When the belt meanders and the widthwise end of the belt comes into contact with the belt contact portion, torque acts on a meandering detection member that is rotatable with respect to the tension roller, and this torque is used to make use of the shaft end of the tension roller. The portion is driven to be displaced such that a reverse force acts on the belt to cancel the meandering component outward in the initial rotation axis direction.

In the above proposed belt fixing device, the shaft end is made of metal, for example, a ball bearing conforming to Japanese Industrial Standard JIS, and is made of, for example, about 160 at the time of fixing.
Grease for heat resistance is used because it can be used at a high temperature of up to 200 ° C. Therefore, such bearings are relatively expensive and cost reduction is desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a belt fixing device and a belt meandering prevention device having a belt meandering prevention function whose structure is simplified and cost can be reduced. To provide.

[0006]

According to the present invention, there is provided an endless belt, a plurality of belt conveying rollers around which the belt is wound and which rotatably supports the belt, a heat source for heating the belt, and a recording paper having a toner image. A belt fixing device including a pressure roller for sandwiching and transporting the belt between the belt and a belt, wherein at least one of the shaft ends of the belt transport rollers is provided with meandering preventing means for preventing belt meandering. A meandering detecting member 120 that has a belt contact portion 123 that is rotatably supported on at least one shaft end of the belt transport roller and that is rotatable with respect to the shaft end, and that has a belt contact portion 123 that contacts the belt; Roller support means 140 for supporting the shaft end supporting the shaft in a predetermined displacement direction orthogonal to the axis of the belt transport roller, and a meandering detecting member, Roller shaft end displacement means for displacing the shaft end supporting the meandering detection member of the belt conveyance roller in the predetermined displacement direction when the belt is brought into contact with the belt contact portion of the output member and torque is applied. 141, and the roller support means 140 rotatably supports the shaft end portion, and has a sliding contact portion having a rolling contact portion on an outer peripheral portion in rolling contact with the predetermined displacement direction.
And a rolling receiving portion that receives the rolling contact portion so that the sliding bearing rolls and is displaced in the predetermined displacement direction.

According to the present invention, an endless belt for fixing is wound around a plurality of belt transport rollers, the belt is heated by a heat source, and toner is transferred between the outer peripheral surface of the belt and the pressure roller. The recording paper having the image is sandwiched, the toner is heated and melted, the toner is fixed to the recording paper, and then the recording paper is peeled off from the belt to perform fixing.

In particular, in the present invention, a meandering detecting member is rotatably supported on at least one of the shaft ends of one of the plurality of belt transfer rollers so as to be rotatable with respect to the shaft end. When the belt is displaced by meandering and comes into contact with the belt contact portion of the meandering detecting member, the meandering detecting member is rotated by frictional contact with the belt, and the rotation of the meandering detecting member is linearly moved by the action of the roller shaft end displacement means. Is converted to Thus, at least one shaft end 24 of the heating roller supporting the meandering detection member is displaced in a predetermined displacement direction. Accordingly, when the at least one shaft end of the heating roller is displaced, a meandering displacement is generated in the belt in the opposite direction, and the initial meandering is eliminated. In this manner, the displacement of the at least one shaft end of the heating roller corresponding to the initial meandering displacement amount is automatically given, and the meandering is eliminated and the belt runs stably.

The meandering detecting member, that is, the meandering detecting means, may be supported on both shaft ends of the one belt conveying roller, or may be supported on only one of the shaft ends.

According to the present invention, the shaft end is supported by a slide bearing, and therefore has a configuration that is smaller than that of a configuration using a rolling bearing such as a ball bearing used in a certain proposed belt fixing device described above. Simplified,
Therefore, the cost is reduced. The plain bearing may be made of a heat-resistant synthetic resin, for example, may be made of a polyamide-imide resin or the like, or may be made of ceramic, sintered metal, or the like, and can be molded.

Further, according to the present invention, FIGS.
As shown in FIG. 9 and FIG. 22, rolling contact portions 178, 179; 184, 185 for displacing in a predetermined displacement direction for preventing meandering are formed in the sliding bearing, and the rolling contact portions are fixed. Rolls are received by rolling receiving portions 181, 182; 186, 187 provided on the apparatus body side. Thus, when the belt is meandering, the rolling contact portion is received by the rolling receiving portion and rolls, and is displaced in the predetermined displacement direction. Therefore, when the belt is displaced by meandering and frictionally contacts the belt detecting portion of the meandering detecting member and a torque acts on the meandering detecting member, the slide bearing can easily roll and displace in the predetermined displacement direction. As a result, the meandering of the belt can be reliably eliminated, and the belt can run stably.

The friction coefficient of the rolling friction is determined by the material of the rolling contact portion and the receiving portion, and the rolling friction coefficient is, for example, about 0.005. In another embodiment of the present invention, when the sliding bearing is displaced in the predetermined displacement direction by the sliding friction toward the fixing device main body, the sliding friction coefficient is, for example, about 0.15-0. 2. Thus, according to the present invention, the sliding bearing can be displaced in the predetermined displacement direction with a small rolling friction coefficient of about 1/30 to 1/40 of the sliding friction coefficient. Therefore, only a slight torque acts on the meandering detecting member due to the meandering of the belt, and the shaft end provided with the meandering preventing means of the one belt conveyance roller is displaced to prevent the meandering of the belt with high accuracy. Will be able to do it.

Further, according to the present invention, the meandering preventing means is provided only at one shaft end of the one belt transport roller, has a rolling receiving portion, and is provided with the one belt transport roller.
One support member 45 provided on the fixing device main body so as to be movable in a direction in which the belt tension is applied, and another slide bearing rotatably supporting the other shaft end of the one belt transport roller. The other support member 73 provided on the fixing device main body and the one support member 45 so as to support the other slide bearing and move the one belt conveyance roller in a direction for applying belt tension. The other support member 73 includes a belt tension applying spring for applying a belt tension.

According to the present invention, both of the two shaft ends of the one belt transport roller, in which the meandering preventing means is provided only at one shaft end, are provided with one and the other support members 45 to 73 by slide bearings. Supported by these two
One of the support members 45 to 73 is provided with a spring force by a belt tension applying spring, whereby tension is applied to the belt, and a rolling receiving portion is formed on the one supporting member to receive a rolling contact portion of the slide bearing. . In this way, meandering of the belt can be eliminated with high accuracy, and an appropriate tension can be applied to the belt, so that the fixing quality can be improved.

Further, according to the present invention, the rolling contact portion is one of a plurality of convex portions or concave portions provided at intervals in the predetermined displacement direction, and the rolling receiving portion is
One of the plurality of convex portions or concave portions provided at intervals in the predetermined displacement direction.

According to the present invention, the rolling contact portion and the receiving portion are constituted by a plurality of convex portions or concave portions, and the displacement of the slide bearing in the predetermined displacement direction at the time of meandering of the belt with a small rolling friction coefficient. Achieved,
In addition, the configuration can be simplified.

Further, the present invention is characterized in that the rolling contact portion and the receiving portion are disposed on the side of the sliding bearing in the belt reaction force direction.

According to the present invention, the rolling contact portion and the rolling receiving portion for receiving the rolling contact portion are on the side of the sliding bearing in the belt reaction force direction, that is, on the side of the remaining belt conveying roller where the meandering detecting member is not provided, for example, the fixing portion. It is arranged on the roller side. Therefore, even if the tension applied to the belt decreases, the rolling contact portion can be reliably received by the rolling receiving portion, and the meandering of the belt can be reliably prevented regardless of the fluctuation in the magnitude of the belt tension. it can.

Further, according to the present invention, the one supporting member includes:
A meandering detection spring that partially surrounds the sliding bearing in the circumferential direction and applies a spring force in a direction opposite to the predetermined displacement direction is provided. In the sliding bearing, the meandering detection spring and the one support are provided. A pair of flanges 161 and 163 sandwiching the member
Is formed, and the one support member is supported by the fixing device main body in the axial direction of the one belt conveyance roller while being prevented from being displaced. The another slide bearing or the other support member is provided with a fixing device. The main body is supported such that the one belt conveyance roller can be displaced in the axial direction.

According to the present invention, the plain bearing is made of, for example, a synthetic resin and can be easily manufactured by injection molding using a mold.

A pair of flanges 161 and 163 are formed on the sliding bearing, and a meandering detection spring 127 that applies a spring force in a direction opposite to the predetermined displacement direction is partially surrounded between the flanges. And the one support member 45 is interposed. In this way, the sliding bearing 26, the one support member 45, and the meandering detection spring 127 can easily support the one belt conveyance roller provided with the meandering preventing means while preventing the one belt conveying roller from being displaced in the axial direction. It is.

The other slide bearing of the one belt transport roller or the other support member is supported by the fixing device main body so as to be displaceable in the axial direction. This makes it possible to thermally expand the one belt transport roller in a high humidity state at the time of fixing, and also to prevent the belt meandering with high accuracy.

According to another aspect of the present invention, an endless belt, a plurality of belt conveying rollers around which the belt is wound, and a belt for rotating and supporting the belt, a heat source for heating the belt, and a recording paper having a toner image are transferred between the belt. And a pressure roller that sandwiches and conveys between the belt conveying rollers, at least one shaft end of one of the belt conveying rollers is provided with meandering preventing means for preventing belt meandering, ,
A meandering detection member 120 having a belt contact portion 123 that is rotatably supported on at least one shaft end of the belt conveying roller and that is rotatable relative to the shaft end, and that contacts the belt; and a shaft end that supports the meandering detection member. The roller support means 140 for supporting the portion displaceably in a predetermined displacement direction orthogonal to the axis of the belt transport roller, and connected to a meandering detection member,
A roller shaft end displacement that displaces the shaft end supporting the meandering detection member of the belt conveyance roller in the predetermined displacement direction when the belt comes into contact with the belt contact portion of the meandering detection member and torque is applied. Means 141, the roller supporting means 140 rotatably supports the shaft end, and has a sliding bearing having an outer peripheral portion having a displacement guide portion extending parallel to the predetermined displacement direction. Is a belt fixing device which is formed on the fixing device main body side and is slidably displaceable by being fitted into a displacement guide hole formed extending parallel to the predetermined displacement direction.

According to the present invention, since the belt conveying roller provided with the meandering preventing means is supported by the slide bearing, the configuration is simplified as compared with the configuration using a rolling bearing such as a ball bearing as described above. And cost reduction is achieved.

Further, according to the present invention, as shown in FIGS. 18 to 21, which will be described later, the displacement guide portion of the slide bearing is formed on the fixing device main body side, for example, on the one support member or the side plate of the fixing device main body. The slide bearing can be slid and displaced by being fitted into the displaced guide hole, thereby preventing the rotation of the slide bearing. In this way, the sliding bearing is suppressed from being worn by contact with the inner peripheral surface of the displacement guide hole such as the one of the support members that support it or the side plate of the fixing device main body, and the sliding bearing can have a long life. . This is advantageous, for example, in a configuration in which the sliding bearing is made of a synthetic resin and the one of the supporting members for supporting the sliding bearing or the side plate of the fixing device main body is made of metal.

According to the present invention, the meandering detecting member comprises
Provided only on one shaft end of the two belt transport rollers,
This shaft end is prevented from displacing the belt conveying roller in the axial direction with respect to the fixing device main body, and the other shaft end is freely supported so as to be displaceable in the axial direction. Therefore, in a state where the one belt conveying roller is thermally expanded and extended in the axial direction by the heat source, the one axial end is prevented from being displaced in the axial direction, so that the side end of the belt is in contact with the contact surface. The belt does not meander while being kept in contact with the belt. In this way, even if the belt conveyance roller, for example, the heating roller is thermally expanded by the heat source, meandering of the belt is reliably prevented, and the side end is maintained at a predetermined position of the fixing device main body.

Further, the present invention is characterized in that the belt contact portion 123 of the meandering detecting member has a contact surface 122 which faces the belt and is substantially perpendicular to the rotation axis.

According to the present invention, it is important that the contact surface facing the side end of the belt formed at the belt contact portion 123 of the meandering detecting member is substantially perpendicular to the rotation axis of the one belt conveying roller. is there. Thus, unlike a configuration in which the contact surface is formed in a truncated cone-shaped tapered portion having a slight apex angle of, for example, 0.75 to 2.0 degrees with respect to the rotation axis, a meandering belt is formed. It does not ride on the taper. According to the present invention, only the side end of the belt comes into contact with the contact surface during meandering, and applies a torque to the meandering detection member. As a result, the coefficient of friction of the contact surface of the meandering detection member with the belt does not depend on the adhesion of foreign substances such as toner and oil, and is substantially independent of the high humidity temperature load of about 160 to about 200 ° C. during fixing. It is kept constant, and the torque can reliably act on the meandering detection member. Mutual displacement of the one belt conveyance roller and the meandering detection member in the rotation axis direction is prevented.

According to the present invention, the contact surface formed on the belt contact portion 123 of the meandering detecting member is approximately 70 degrees relative to its axis in a plane including the axis of the belt conveying roller on which the meandering detecting member is supported. It is formed substantially vertically as described above with an angle θ1 of up to 90 degrees. The angle θ1 is set to the contact surface from the same position as the outer peripheral surface of the belt guide that guides the belt of the belt conveyance roller on which the meandering detection member is supported.
Extend. In this way, the side edge of the belt comes into contact with the contact surface, and the meandering of the belt is prevented as described above. Angle θ1
Is an angle that is less than 90 degrees and approximates 90 degrees. The term “substantially perpendicular” refers to an angle θ1 of about 70 to 90 degrees with respect to the axis of the shaft end.

Further, the present invention is characterized in that the one belt transport roller is a heating roller provided with a heat source.

According to the present invention, the belt conveying roller provided with the meandering preventing means is a heating roller.

That is, in the present invention, since the heating roller is provided with the belt meandering prevention means as described above, it is not a configuration using a tension roller having a mechanism for preventing the belt meandering described above, and therefore, the structure can be reduced in size. Can be achieved, cost is reduced, heat loss is reduced,
Further, the contact angle in the circumferential direction of the heating roller with which the belt is wound around and in contact with the heating roller can be increased, so that the heat transfer from the heating roller to the belt can be performed well, thereby shortening the heating time and saving. The energy effect can be improved. In this way, it is possible to prevent the belt from meandering while utilizing the advantageous characteristics without impairing the characteristics of the belt fixing. Means for preventing meandering are provided in connection with the heating roller, thereby reducing the number of parts. Further, since the belt can be prevented from meandering, the life of the belt can be extended even under a high temperature condition of about 160 to 200 ° C. for fusing the toner.

The present invention also provides an endless belt, a plurality of belt transport rollers around which the belt is wound and which supports the belt, and a belt meandering at least one shaft end of one of the belt transport rollers. Meandering preventing means is provided, and the meandering preventing means has a belt contact portion 123 which is rotatably supported on at least one shaft end of the belt transport roller and is rotatable with respect to the shaft end, and which comes into contact with the belt. Roller support means 140 for supporting the meandering detection member 120 and the shaft end supporting the meandering detection member in a predetermined displacement direction orthogonal to the axis of the belt transport roller.
And, connected to the meandering detection member, when the belt is in contact with the belt contact portion of the meandering detection member and torque is applied, the shaft end supporting the meandering detection member of the belt transport roller,
A roller shaft end displacing means 141 for displacing in the predetermined displacement direction, wherein the roller supporting means 140 rotatably supports the shaft end and makes rolling contact with an outer peripheral portion in the predetermined displacement direction. A belt meandering prevention device comprising: a sliding bearing having a rolling contact portion; and a rolling receiving portion that receives the rolling contact portion such that the sliding bearing rolls and is displaced in the predetermined displacement direction.

According to the present invention, it is possible to displace the shaft end in the predetermined displacement direction with a slight rolling friction in the meandering of the belt. Therefore, meandering of the belt can be prevented with high accuracy.

[0035]

FIG. 1 is a horizontal sectional view of a part of a belt fixing device 1 according to an embodiment of the present invention, and FIG.
3 is a horizontal sectional view of the remaining part of the belt fixing device 1, and FIG.
5 is a simplified longitudinal sectional view of the belt fixing device 1. FIG. FIG. 1 is a cross-sectional view taken along a section line II in FIG. 6 described below, and FIG. 2 is a cross-sectional view taken along a section line II-II in FIG. FIG. 3 is a sectional view taken along the line III-III in FIG.
FIG. 4 is a sectional view taken along line IV-
It is sectional drawing seen from IV. With reference to these drawings,
The belt fixing device 1 is used by being built in an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile machine. In the fixing device main body 2, an endless belt 6 is wound between the fixing roller 3 and a hollow heating roller 5 through which the elongated heat source 4 is inserted. A pressure roller 7 is disposed directly below the fixing roller 3. The recording paper 8 having the toner image on the upper surface is arranged from the bottom to the top in FIGS.
5 and from right to left in FIG. The recording paper 8 is held by a pressure roller 7 and pressed against a belt 6 heated to, for example, about 160 to 200 ° C. over a relatively long distance, whereby the toner image is heated and melted, and then cooled and fixed. Is performed. These fixing roller 3, heat source 4, heating roller 5
The pressure roller 7 has a substantially horizontal axis. The recording paper 8 is guided by upper and lower guide members 10 and 11 on the entrance side and guided by guide members 12 and 13 on the exit side.

The heating roller 5 may be made of a metal material having a good thermal conductivity, for example, a material such as aluminum. The fixing roller 3 has a layer having at least a surface having elasticity. The pressure roller 7 has a configuration in which a layer made of a synthetic resin material such as Teflon (trade name) is formed on a metal surface such as aluminum to prevent foreign substances such as toner and oil from adhering. Is also good.

Of the two side plates 14 and 15 of the fixing device main body 2, an insertion hole 66 is formed in the side plate 14 as clearly shown in FIG. Using the insertion hole 66, the belt 6 can be detached to the right in FIGS. 3 and 4 to be detached or inserted into the fixing device main body 2.
The shaft ends 17, 18 of the fixing roller 3 are supported by bearings 19, 20. A drive gear 22 is detachably connected to the shaft end portion 18 by a retaining ring 21, whereby the fixing roller 3 is driven to rotate, and the belt 6 is run by this power. Thus, the heating roller 5 and the pressure roller 7 are driven to rotate. Shaft end 2 of heating roller 5
3 and 24 are supported by slide bearings 25 and 26.

FIG. 6 is a left side view of the fixing device main body 2.
FIG. 7 is a perspective view of the bearing 26 and its vicinity, and FIG. 8 is an exploded perspective view of the vicinity of the left side plate 15 of the fixing device main body 2.
The shaft end 31 (see FIG. 12 described later) and the shaft end 32 (see FIG. 8) of the pressure roller 7 are supported by bearings 33 and 34.

Referring again to FIG. 5, a pressure lever 35 and a pressure spring 36 are provided near the side plate 14 to apply a spring force to the pressure roller 7 in a direction toward the fixing roller 3. One end of the pressure lever 35 is provided to be angularly displaceable by a pin 37 having an axis parallel to the axis of the pressure roller 7. The other end 38 of the pressure lever 35 has a spring 3
One end 39 of 6 is detachably locked. The other end 40 of the spring 36 is detachably locked by a locking piece 41 protruding from the side plate 14. The pressure lever 35 abuts on the peripheral surface of the bearing 33 on the side opposite to the fixing roller 3 (downward in FIG. 5),
Due to the spring force of the spring 36, the pressure lever 35 is given a counterclockwise spring force in FIG. 5 around the axis of the pin 37.
Thus, the pressing roller 7 is applied with a spring force toward the fixing roller 3, and the pressing roller 7 is pressed against a portion of the belt 6 that is wound around the fixing roller 3. The shaft end 32 of the pressure roller 7 is also provided with a configuration similar to the above-described pressure lever 35 and spring 36 symmetrically with respect to the shaft end 31 in relation to the side plate 15.

In order that the bearing 33 can be displaced in the vertical direction, which is the radial direction of the fixing roller 3, the side plate 14
As shown in FIGS. 11 and 12, an oval guide elongated hole 42 extending vertically is formed in the side plate 15 in the same manner as shown in FIGS. The guide slot 43 is formed as shown in FIG. Bearings 33 and 34 are fitted and guided in these guide slots 42 and 43. The shaft ends 31 and 32 of the pressure roller 7 are
Is smaller than the outer diameter of the pressure roller body to be pressed and smaller than the outer diameter of the bearings 33 and 34, and can be removed from the insertion hole 66 and can be inserted. Further, the shaft ends 31, 32 are detachable from the bearings 33, 34.

A support member 45 is disposed outside the side plate 15 of the fixing device main body 2 (to the left in FIGS. 1 and 2 and above the plane of FIG. 6). The support member 45 is movable in the radial direction of the fixing roller 3 (the vertical direction in FIG. 1 and the horizontal direction in FIG. 6).
It is guided by the guide pieces 46 and 47. Guide pieces 46, 4
7 are detachable mounting bolts 118, 1 attached to the side plate 15.
Guide portions 48 and 4 fixed between the side plates 15 and fixed to the side plate 15 by guide grooves for guiding the upper and lower sides of the support member 45.
9

The support member 45 is formed with an oval guide elongated hole 50 that is elongated in the vertical direction perpendicular to the radial direction of the fixing roller 3. The guide slot 50 includes parallel portions 156 and 157 extending parallel to the vertical direction, and the parallel portions 15 and 157.
6, 157, and 157.
The bearing 26 that supports the shaft end 24 of the heating roller 5 is disposed in the guide slot 50. The shaft end 24 is inserted through the bearing 26. The outer side of the support member 45, that is, the side plate 15
On the opposite side (left side in FIGS. 1 and 2)
A flange portion 161 which is an outward flange of No. 6 is disposed, and a straight cylindrical holding portion 162 is fitted and guided in the guide elongated hole 50, and further, the flange portion 161 is connected to the flange portion 161 via the holding portion 162. Another flange 163 is formed on the opposite side. The holding portion 162 and the flange portion 163 are connected to the guide slot 50 from FIG.
2 and on the lower side of FIG. 7. Thus, the bearing 26 is prevented from displacing the shaft end 24 inward in the axial direction (to the right in FIGS. 1 and 2). Heating roller 5
An annular groove is formed in the shaft end 24 of the retaining ring 5.
4 resiliently and removably fits, thereby preventing axial end 24 from displacing axially inward (to the right in FIGS. 1 and 2). The shaft end 24 passes through a support hole 164 formed coaxially with the holding portion 162 in the bearing 26.
The surface 165 of the flange portion 163 on the side of the flange portion 161 is formed in a truncated cone shape such that the diameter becomes smaller toward the outside in the axial direction (to the left in FIGS. 1 and 2). Between the flanges 161 and 163,
The support member 45 and the meandering detection spring 127 are arranged in order from the outside in the axial direction to the inside.

FIG. 9 is an exploded perspective view of the vicinity of the support member 45. One end 56 of the belt tension applying spring 55 shown in FIGS. 1 and 6 is detachably locked to the support member 45. The other end 57 of the spring 55 is detachably connected to the side plate 15. Thus, the spring 55 is connected to the support member 4.
5, and thus the heating roller 5 is provided with a spring force to move away from the fixing roller 3 in the radial direction.

The side plate 15 is provided with a shaft end 24 of the heating roller 5.
An opening 64 is provided to facilitate maintenance of the vicinity, and an elongated opening 65 is formed following the opening 64 and extending in a direction away from the fixing roller 3 with respect to the heating roller 5. The spring 55 is disposed in the opening 65.

A base end 61 of a holder 58 is detachably attached to the support member 45 by a bolt 59.
Holder 58 removably holds end 60 of heat source 4, for example, a halogen lamp. The end portion 60 of the heat source 4 is detachably fitted to the holding portion 62 of the holder 58 as described above. The locking projection 1 is provided at the base end 61 of the holder 58.
12 is formed, an engagement hole 113 is formed in the support member 45 and fitted, and a locking hole 114 for locking the end 56 of the spring 55 is formed. Further, a removable screw hole 115 for the bolt 59 is formed in the support member 45. In association with the support member 45, a belt meandering preventing means 63 for preventing the belt 6 from meandering is provided as described later.

FIG. 10 is a simplified perspective view showing the structure of the heating roller 5 and a part related thereto, FIG. 11 is a right side view of the belt fixing device 1, and FIG. FIG. 2 is an exploded perspective view of a side plate 14 and its vicinity. The side plate 14 is formed with an insertion / removal hole 66 for inserting the belt 6 into the fixing device main body 2 or detaching the belt 6 from the fixing device main body 2. Further, the opening 67 connected to the insertion / removal hole 66 is
Formed. The opening 67 extends in a direction away from the fixing roller 3 with respect to the heating roller 5. The guide slot 42 is
The connection hole 68 communicates with the insertion / removal hole 66 to be connected.
The width W1 of the connection hole 68 (see FIG. 11) is equal to or greater than the outer diameter D1 of the shaft end 31 of the pressure roller 7 (W1 ≧ D1). Therefore, when the bearing 33 is not fitted in the guide slot 42 and the shaft end 31 is not inserted into the bearing 33, the shaft end 31 moves up and down in the connection hole 68 in FIG. can do. The outer diameter of the pressure roller 7 is set to be equal to or less than the vertical distance of the insertion hole 66 in FIG. The configuration in which the bearings 33 and 34 are attached to the shaft ends 31 and 32 of the pressure roller 7 includes a configuration in which the shaft end 23 of the heating roller 5 is supported by the bearing 25 and attached to the support member 73, and another end. This is similar to the configuration in which the portion 24 is attached to the support member 45 by the bearing 26. By detachably removing the retaining rings associated with the bearings 33 and 34, the bearings 33 and 34 can be removed from the shaft ends 31 and 32 of the pressure roller 7.

An E-ring may be used instead of each of the above-mentioned retaining rings.

The bearings 19, 20 and 33, 34 are rolling bearings and their rolling elements 44, 75, 116, 11
Numeral 7 may be a ball, and a sliding bearing may be used in place of the rolling bearing, and can receive a thrust force and a radial force.

Outside the side plate 14 (right side in FIGS. 3 and 4,
A cover 71 that closes the insertion hole 66 and the opening 67 and partially closes the connection hole 68 is disposed on the right side of FIG. The lid 71 includes an auxiliary plate 72 and a support member 73. The auxiliary plate 72 has a bolt insertion hole through which a plurality of (for example, four) bolts 74 are inserted. The bolt 74 is attached to the side plate 14.
Are detachably screwed into the screw holes 76 formed in the holes. In this way, the auxiliary plate 72 is accurately positioned so as to be detachable from the side plate 14 and fixed.

The auxiliary plate 72 includes a shaft end 1 of the fixing roller 3.
The bearing 19 that supports 7 is detachably fitted and mounted. The bearing 25 is detachably fitted to the support member 73. The auxiliary plate 72 has an oval guide elongated hole 77 for guiding the bearing 25 in the radial direction of the fixing roller 3 corresponding to the bearing 25.

The bearing 25 is a flange 1 which is an outward flange.
66 and a displacement guide 167 connected to the flange 166. Outside the support member 73 (right side in FIGS. 3 and 4)
The flange portion 166 is disposed so that the outer ring 78, and thus the bearing 25, is inward in the axial direction of the heating roller 5 (FIG. 3).
(Left of FIG. 4). The shaft end 23 of the heating roller 5 is provided with the support member 7 rather than the bearing 25.
A retaining ring 81 is removably fitted to the outside of 3. Thus, displacement of the shaft end 23 inward in the axial direction (leftward in FIGS. 3 and 4) is prevented.

A locking projection 191 and a locking recess 192 are formed in the outer peripheral portion of the bearing 25 and the guide hole of the support member 73, respectively. The engagement of the locking projections and the locking recesses 192 to lock the rotation of the bearing 25 is prevented. Therefore, it is possible to prevent the bearing 25 made of metal from slipping and coming into contact with the support member 73 and being worn out.

The guide part 167 of the bearing 25 is
Are loosely inserted into the through holes 142 formed in the holes to engage with each other. That is, the guide portion 167 has a long cylindrical shape, and the shaft end portion 23 is inserted and supported in the coaxial support hole 168, and a slight gap is formed between the outer diameter of the guide portion 167 and the inner diameter of the play hole 142. Gaps exist. This allows the shaft end portion 24 of the heating roller 5 to be displaced along the guide slot 50 by the operation of the belt meandering preventing means 63 to allow the axis of the heating roller 5 to be inclined, and to provide belt tension applying springs 55 and 8.
By the operation of 2, the axis of the heating roller 5 is allowed to be inclined.

With respect to the support hole 168 of the bearing 25 and the shaft end 23 of the heating roller 5, the shaft end 23 is supported by the support hole 168 so that mutual displacement is allowed along the axis of the heating roller 5.
Gently. Therefore, the heat source 4 allows the heating roller 5 to expand in the axial direction. Due to the thermal expansion of the heating roller 5 during the fixing operation, as shown in FIG. 4, a gap d2 between the bearing 25 and the retaining ring 81 can be generated. This gap d2 may be, for example, 1.5 to 2 mm during the fixing operation.

On the other hand, the shaft end 24 of the heating roller 5
In particular, as clearly shown in FIG. 2, the mutual displacement of the heating roller 5 with respect to the side plate 15 in the axial direction (left-right direction in FIG. 2) is zero or almost zero,
Of the shaft end 24 and the side plate 15 in the axial direction is prevented. Therefore, displacement of the heating roller 5 along the axial direction of the heating roller 5 with respect to the bearing 26 is prevented by the retaining ring 54 and a retaining ring 138 described later on the shaft end 24, and the guide pieces 46, 47.
Of the side plate 15 by the guide portions 48 and 49 of
And the displacement of the heating roller 5 along the axial direction is prevented. Furthermore, the bearing 26 and the support member 45 are
The support member 45 and the displacement detection spring 127 are interposed between the displacement guide portions 162 between
Is displaced inward (to the right in FIG. 2) along the axis of the heating roller 5 with respect to the support member 45. In order to prevent the shaft end 24 from being displaced axially outward of the heating roller 5 with respect to the support member 45 (to the left in FIG. 2), a spring 127 is substantially provided between the support member 45 and the flange 163. It is interposed exactly.

The support member 73 includes a belt tension applying spring 8.
The second end 83 is detachably locked. The other end 84 of the spring 82 is locked by a spring locking piece 85. Spring 82
Is located at the opening 67. A screw hole 87 is formed in a rising portion 86 of the spring engagement piece 85.

An upright portion 88 is formed below the left side of FIG. 3 (left side in FIG. 11) of the auxiliary plate 72 farther from the heating roller 5 than the spring engagement piece 85. A bolt insertion hole 90 through which the spring force adjustment bolt 89 is inserted is inserted into the upright portion 88. The shaft portion of the bolt insertion hole 90 where the male screw is cut is screwed into the screw hole 87. The bolt head of the bolt 89 comes into contact with the upright portion 88. By angularly displacing the bolt 89 about its axis in this manner, the spring retaining piece 85
And the tension of the belt 6 is adjusted.

The spring retaining piece 85 has an adjusting slot 91 formed along the direction in which the spring 82 extends. Adjustment bolt 9
2 is inserted into the adjusting long hole 91 and screwed into a screw hole 93 formed in the side plate 14. With the bolts 92 thus loosened, the tension of the belt 6 is set by the bolts 89, and then the bolts 92 are tightened to fix the spring locking pieces 85 to the auxiliary plate 72. In correspondence with the auxiliary plate 72 so as to overlap the opening 67 formed in the side plate 14,
An opening 98 is formed. In these openings 67 and 98,
A spring 82 is disposed.

The end 9 of the heat source 4 inserted into the heating roller 5
3 is detachably attached to the end 95 of the holder 94. A bolt 97 is inserted through the base end 96 of the holder 94. The bolt 97 is detachably screwed to the support member 73. Thus, in the support member 73, the heat source 4 and the heating roller 5 are attached to the support member 73 outside the auxiliary plate 72 while keeping the heat source 4 and the heating roller 5 coaxial.

The insertion / removal hole 66 has a shape larger than the cross-sectional outer diameter of the belt 6 stretched around the fixing roller 3 and the heating roller 5. Thus, it is possible to easily pull out the belt 6 to the outside of the side plate 14 and insert it into the fixing device main body 2 while maintaining the substantially stretched shape.

Referring to FIGS. 1 and 2 again, bearing 20 supporting shaft end 18 of fixing roller 3 has outer ring 101, inner ring 102, and rolling elements 116 interposed therebetween. The shaft end 18 is inserted into the inner ring 102, and the displacement of the inner ring 102 in the axial direction outward (to the left in FIGS. 1 and 2) is removably performed by the retaining ring 21 via the drive gear 22 as described above. Will be blocked. The outer ring 101 has a side plate 15
Outside, the snap ring 103 resiliently and removably fits. As a result, displacement of the outer ring 101 inward in the axial direction (rightward in FIGS. 1 and 2) is prevented.

Referring again to FIGS. 3 and 4, bearing 19 for supporting shaft end 17 of fixing roller 3 has outer ring 104, inner ring 105, and rolling elements 117 interposed therebetween. The outer ring 104 has a retaining ring 1 outside the auxiliary plate 72.
06 fits resiliently and removably. A retaining ring 107 is removably and resiliently fitted to the shaft end 17 outside the inner ring 105. In this way, the displacement of the outer ring 104 and thus the bearing 19 inward in the axial direction (to the left in FIGS. 3 and 4) is prevented, and the inner ring 105 and therefore the bearing 1
9 is prevented from moving outward in the axial direction (to the right in FIGS. 3 and 4). The fixing roller 3 includes the retaining ring 2 shown in FIG.
1, 103 and retaining rings 106, 107 shown in FIG.
Accordingly, axial displacement with respect to the fixing device main body 3 including the side plates 14 and 15 is prevented.

The bolt 97 is screwed into the screw hole 108 of the support member 73 as clearly shown in FIG. An engagement protrusion 109 is formed at the base end 96 of the holder 94 so as to bend toward the support member 73 in the axial direction of the heating roller 5. The engagement protrusion 109 is detachably engaged with an elongated engagement hole 110 formed in the support member 73. When the bolt 97 is tightened in this manner, the holder 94 is not angularly displaced around the axis of the bolt 97, and therefore, the state in which the axis of the heat source 4 is exactly aligned with the axis of the heating roller 5 is maintained. Become. The spring 82 connected to the engagement hole 110
The locking holes 111 for locking the end portions 83 are continuous. The same applies to the holder 58.

When removing the belt 6 wound around the fixing roller 3 and the heating roller 5, the ends 56, 57; 83, 8 of the belt tension applying springs 55, 82 are removed.
4 is removed, and the tension of the belt 6 is released. Also, one of the ends 39 and 40 of the spring 36 related to the bearing 33 of the pressure roller 7 is removed to release the pressing force, and another bearing 34 of the pressure roller 7 (see FIG. 6 described above). In the same manner, the pressing force is released.

Next, the bolts 59, 97 fixing the holders 58, 94 are loosened or removed, and the holder 5
8, 94 to the ends 60, 93 of the heat source 4.
The heat source 4 is removed from the heating roller 5. The retaining rings 81 and 107 provided in relation to the bearing 25 of the heating roller 5 and the bearing 19 of the fixing roller 3 are removed. Thereafter, the bolts 74 fixing the auxiliary plate 72 are removed, and the lid 71 is removed from the side plate 14 in this manner. This allows the insertion / removal hole 66
Faces the outside. In this state, the belt 6 can be pulled out of the side plate 14 from the insertion hole 66.

The belt 6 can be pulled out of the side plate 14 from the insertion / removal hole 66 as described above. In addition, the heating roller 5 and the fixing roller 3 can be individually taken out as follows. Furthermore, the belt 6 and the heating roller 5
It is also possible to pull out the fixing roller 3 and the fixing roller 3 from the insertion / removal hole 66 to the outside of the side plate 14 at the same time.

Prior to removing the heating roller 5 from the insertion hole 66, first, the retaining rings 53 and 54 are removed, and the end 60 of the heat source 4 is removed from the end 62 of the holder 8. Further, the end 135 of the cable 132 is removed from the pin 136 fixed to the support member 45. Thus, the heat source 4 can be drawn out of the side plate 14 together with the heating roller 5.

Further, the fixing roller 3 is fixed to the fixing device main body 2.
In order to remove the retaining ring, the retaining ring 21 attached to the shaft end 18 in FIG. 1 is removed. Thereby, the fixing roller 3 can be taken out from the side plate 14 through the insertion / removal hole 66.

Further, it is also possible to take out the pressure roller 7 from the fixing device main body 2 through the insertion / removal hole 66. For this purpose, first, the shaft ends 31 (FIG. 12) and 32 of the pressure roller 7 are
The bearings 33 and 34 are removed from (FIG. 5). Bearings 33, 34
Is removed from the guide slots 42 and 43 of the side plates 14 and 15.
Therefore, the shaft end 31 of FIG. 12 is provided to the insertion / removal hole 66 via the connection hole 68. Thus, the pressure roller 7 can be taken out of the side plate 14 through the insertion hole 66.

The heating roller 5 is moved from the fixing device main body 2 to the side plate 1.
5 can also be taken out. For this purpose, together with the support member 45 shown in FIG. 1 and the belt meandering preventing device 63, the heating roller 5 can be taken out of the side plate 15 from the opening 64 shown in FIG. Thereby, it is not necessary to disassemble the belt meandering prevention device 63, and the workability is good.

Prior to the removal of the heating roller 5, the guide pieces 46, 47 are attached to the mounting bolts 1 from the side plate 15.
18, 119 can be detachably detached, so that the support member 45 can be detached from the side plate 15. Alternatively, the end portion 60 of the heat source 4 is removed from the end portion 62 of the holder 58, and the bearing 2 supporting the shaft end portion 24 of the heating roller 5 is further removed.
The bearing 26 is removed from the support member 45 by removing the retaining ring 53 for 6, and in this state, the heat source 4 and the heating roller 5 are displaced inward of the fixing device main body 2. Thus, the support member 45 can be moved along the guide pieces 46 and 47, for example, to the right in FIG. 6, and can be removed.

The belt meandering preventing means 63 will be described with reference to FIGS. 1, 2, 6, 7, and 10. The meandering detection member 120 is disposed at the shaft end 24 of the heating roller 5, and the shaft end 24 is rotatably inserted through each other, whereby the meandering detection member 120 is supported by the shaft end 24. The outer diameter of the shaft end 24 is formed to be smaller than the outer diameter of the belt guide 121 that guides the belt 6 of the heating roller 5.

The meandering detecting member 120 is provided with a contact surface 122
And a belt contact portion 123 having Contact surface 122
In a plane including the rotation axis of the heating roller 5, an angle θ1 (see FIG. 2) formed with the axis is selected to be substantially perpendicular.
Contact surface 12 of belt guide portion 123 of meandering detection member 120
2 indicates that the angle θ1 (see FIG. 2) formed with the axis of the heating roller 5 in the plane including the axis is substantially perpendicular, that is, 90 degrees.
Or a value less than 90 degrees and approximately 90 degrees, for example in the range of 70-90 degrees, or 85
The angle may be selected from the range of 90 to 90 degrees, or may be 89 degrees. When the angle θ1 is less than 70 degrees and the angle θ1 exceeds 90 degrees, it is possible to reduce the meandering amount of the belt 6 and prolong the life of the belt 6 by setting the angle θ1 to be almost vertical as described above. Confirmed by experiments. The outer diameter of the end 124 on the small diameter side of the contact surface 122 of the belt contact portion 123 is preferably equal to the outer diameter of the belt guide 121 of the heating roller 5.
21 may be less than the outer diameter of contact surface 122
The outer diameter of the annular connection position between the belt guide portion 121 and the end surface of the end portion 124 may be smaller than the outer diameter of the belt guide portion 121.

The shaft end 24 has an outer diameter smaller than the belt guide 121 on which the belt 6 of the heating roller 5 is wound. The shaft end 24 coaxially inserts the meandering detection member 120. An axially outward (leftward in FIG. 1) end of the shaft end 24 is supported by a support member 45 via a bearing 26.

The above-described guide slot 50 is formed in the support member 45 constituting the roller support means 140. The guide slot 50 allows the bearing 26 to be displaced in the direction perpendicular to the plane of FIG. 1, that is, the vertical displacement in FIGS. 6 and 8. The direction in which the guide slot 50 extends is perpendicular to the vertical direction of the support member 45 in FIG. 1 and the horizontal direction in FIGS. 6 and 8.

The belt contact portion 123 of the meandering detection member 120
A straight cylindrical cable guide portion 125 is integrally formed outwardly in the axial direction (leftward in FIGS. 1 and 2). The cable guide portion 125 is formed with a flange 126 that protrudes radially outwardly toward the outside of the cable guide portion 125 in the axial direction (to the left in FIGS. 1 and 2). Flange 12
The outer peripheral surface of 6 is formed in a truncated conical shape whose outer diameter increases as it goes outward from the cable guide portion 125 in the axial direction.

Further, the meandering detection spring 127 is
A substantially lower half of the displacement guide 162 is substantially surrounded by a U-shape. Two upper ends 128 and 12 of the meandering detection spring 127
9 is locked to the pins 130 and 131 of the support member 45. Thus, a spring force is applied to the bearing 26 in the guide slot 50, and thus to the shaft end 24 of the heating roller 5, in one direction upward in the plane of FIG. 1 and upward in FIGS.

FIG. 13 is a simplified diagram showing a state where the belt 6 is wound around the fixing roller 3 and the heating roller 5. In FIG. 13, when the belt meanders, the heating roller 5 is displaced by the rolling of the slide bearing 26 as shown by the imaginary line and as shown by the reference numeral 5a, and the belt is shown by the reference numeral 6a at this time. The heating roller 5 is pulled rightward in FIG. 13 by the belt tension applying springs 55 and 82 to be applied with a spring force. Therefore, the belt 6 generates a reaction force 175 toward the fixing roller 3. When the belt 6 does not meander, the heating roller 5, and thus the bearing 26, is moved by an arrow 1 by the action of a meandering detection spring 127.
When the belt 6 is displaced in the direction of 76 and the meandering of the belt 6 occurs, the belt 6 is displaced in the direction of the arrow 177 to prevent the belt from meandering. The displacement d3 of the heating roller 5 may be, for example, 1 to 2 mm.

FIG. 14 is a partial cross-sectional view showing a state where the bearing 26 is supported in the elongated guide hole 50 so as to allow rolling contact. A plurality of (for example, two in this embodiment) rolling contact portions 178 and 179 are formed on the slide bearing 26 on the side of the direction of the belt reaction force 175 (to the left in FIGS. 13 and 14). You. This rolling contact portion 17
Between 8,179, there is a depression as indicated by reference numeral 180. Rolling contact portions 178 and 179 extend in parallel along the axis of bearing 26 and heating roller 5.

In the guide long hole 50 of the support member 45, the parallel portion 156 has a rolling receiving portion 181, 1 as a concave portion.
82 are formed. Rolling receiving portions 181, 182
Between them, a low ridge 183 is formed corresponding to the depression 180 so as not to contact the inner peripheral surface of the depression 180.

The rolling contact portions 178 and 178 shown in FIG.
The distance between 179 and the distance between the rolling receiving portions 181 and 182 are equal. The rolling receiving portions 181 and 182 are provided with the rolling contact portions 178 and 179 extending parallel to the axis of the bearing 26 and the heating roller 5.
82 are received in line contact with each other.

In a state where the belt 6 does not meander and the side end of the belt 6 does not contact the belt contact surface 122, FIG.
As shown in (1), the rolling contact portion 178 is received by the rolling receiving portion 181. When the belt 6 meanders and comes into contact with the belt contact surface 122, torque acts on the meandering detection member 120, and thus the rope 132
Is wound around the cable guide portion 125, whereby the bearing 26
As shown in FIG. 14 (2), the two rolling contact portions 178, 179 have two rolling receiving portions 181, 1
As shown in FIG. 14 (3), the rolling contact portion 179 passes through the state in which the rolling contact portion 179 abuts on the rolling receiving portion 1
The meandering detection spring 1 is placed in a state in which
27 can be displaced against the spring force. In this way, when the belt 26 meanders, the rolling contact portions 178 and 179 are in rolling contact with the rolling receiving portions 181 and 182 and are displaced in a predetermined displacement direction indicated by an arrow 177 in FIG. The bearing 26 can be displaced by rolling friction. As a result, the bearing 2
6, the displacement direction 1 of the shaft end 24 of the heating roller 5
The displacement of 77 can be made with a small torque, and the meandering of the belt can be prevented with high accuracy. The operation of preventing the belt from meandering will be described as follows.

When the upper end of the bearing 26 is in contact with the upper end 143 of the elongated hole 50 (see FIG. 7) due to the spring force of the spring 127, the belt 6 is heated in the width direction of the belt 6 and, hence, heated. The vehicle travels displaced toward the meandering detection member 120 in the axial direction of the roller 5.

The cable 132 is flexible and does not expand or contract, and its one end 133 is connected to the meandering detecting member 120 by a pin 134 as clearly shown in FIG. It is fixed to the strip guide 125. The other end 135 of the cable 132 is detachably connected to and fixed to the support member 45 by a pin 136. This cable 1
Reference numeral 32 is partially wound around the cable guide portion 125 in the circumferential direction on the side substantially opposite to the meandering detection spring 127, for example, about half a turn. In a state where the belt 6 does not meander, and thus the side end of the belt 6 is not in contact with the belt contact surface 122, the state of FIG. 14A is maintained. Thus, when the rope detection member 120 is angularly displaced in the arrow 137 (see FIG. 8) in the same rotation direction as the heating roller 5, the rope 132 is wound around the rope guide portion 125. This causes the shaft end 24 of the heating roller 5 to move against the spring force of the meandering detection spring 127 in one direction above in FIGS. Displace in the other direction below. Thus, the bearing 26
After the state shown in FIG. 14 (2), the state shown in FIG. 14 (3) is obtained.

When the belt 6 meanders and comes into contact with the contact surface 122 of the belt contact portion 123 of the meandering detection member 120, a large rotational torque acts on the meandering detection member 120 according to the amount of meandering in the belt width direction. As a result, the cable 132 is wound around the cable guide 125. As a result, the shaft end 24 is displaced downward in FIGS. Therefore, a meandering component toward the side plate 14 is generated in the belt 6, and the shaft end 24 is displaced downward along the guide slot 50 until the initial meandering component toward the side plate 15 cancels out. become.

As described above, the belt 6 meanders and comes into contact with the contact surface 122 of the belt contact portion 123, so that a frictional force acts between the belt 6 and the contact surface 122, and thus the meandering detecting member as described above. 120 is rotated with respect to shaft end 24. Due to this rotation, as described above, the rope 1
32 winds around the cable guide portion 125. The winding force of the rope 132 and the spring force of the meandering detection spring 127 are balanced, and the amount of downward displacement of the shaft end 24 in FIGS. 6 and 7 is regulated.
Is maintained on the contact surface 122.

When the shaft end 24 is displaced downwardly in FIGS. 6 and 7 as described above, the heating roller 5
On the side of the shaft end 23, the bearing 25 is loosely inserted with a gap into the through hole 142 of the support member 73 as clearly shown in FIG. In the embodiment, the axis of the heating roller 5 may be inclined with respect to one virtual plane including the axis of the fixing roller 3 due to the elastic deformation of the support member 73 or the backlash of the bearing 25. Permissible. This allows the shaft end 24 to be displaced downward in FIGS. 6 and 7 to prevent belt meandering as described above.

Referring to FIG. 1 and FIG.
6, the axial end portion 2 is located outward of the axial end portion 24 in the axial direction.
4, a retaining ring 138 is detachably attached. By the action of the retaining ring 138, the meandering detection member 120 is prevented from displacing the shaft end 24 outward in the axial direction. The end portion 124 of the meandering detection member 120 abuts on the end surface of the belt guide portion 121 of the heating roller 5, and the displacement in the axial direction inward (to the right in FIGS. 1 and 2) is limited.

Further, due to the function of the flange portion 163, the curved portion of the meandering detection spring 127 wound around the U-shape from the outer peripheral surface of the holding portion 162 is displaced to the right in FIGS. Is prevented. In this way, the meandering preventing operation of the belt 6 is reliably achieved.

A rope guide portion 125 formed integrally with the meandering detecting member 120, a meandering detecting spring 127,
32 is a roller shaft end displacement means 141.
Is configured.

In another embodiment of the present invention, the cord 132
, A meandering detection spring 127 is used.
May be omitted. Instead of using the cable 132, a coaxial pinion is fixed to the meandering detection member 120, and the support member 4
5, a rack meshing with the pinion may be fixed so that the shaft end 24 may be displaced. Alternatively, one end of a rigid rod may be pin-connected to the side wall of the meandering detection member 120, The end may be pin-connected to the support member 45 so that the shaft end 24 is displaced when the belt 6 meanders.

The belt 6 has a thickness of, for example, 40 to 50 μm.
Is about 120 μm thick on the outer surface of Ni which is a metal material having a relatively small coefficient of thermal expansion to prevent toner offset.
Has a configuration in which a coating layer made of a synthetic resin such as a silicon resin is formed. The meandering detection member 120 may be made of metal, or may be made of a synthetic resin material having excellent wear resistance, for example, a polyamideimide-based synthetic resin.

[0093] The experimental results of the present inventor will be described. In the embodiment of the present invention described with reference to FIGS. 1 to 14 described above, the belt 6 has a configuration in which an outer peripheral surface of Ni having a thickness of 50 μm is coated with a silicon resin having a thickness of 120 μm. The experimental results of the present inventor when the traveling speed of the belt 6 is 200 mm / min and the pressure of the pressure roller 7 applied to the fixing roller 3 via the belt 6 is 18.5 kgf are as shown in Table 1 and FIG. became. Other test conditions of this experiment are as shown in Table 1.

[0094]

[Table 1]

The belt life means that a crack has occurred in the belt 6. As is clear from Table 1 and FIG. 15, in the example, the life of the belt 6 was longer than those of the comparative examples 1 and 2.
, And it was confirmed that the position of the belt 6 could be regulated with high accuracy.

The meandering amount at the time of warm-up in Table 1 indicates the meandering amount of the belt immediately after the power is turned on. The shake amount indicates a meandering amount of the belt during the fixing operation.

FIG. 16A shows the amount of meandering of the belt 6 over time in the embodiment shown in Table 1. FIG. 16 (2)
Represents the meandering amount of the belt 6 of Comparative Example 1 during the fixing operation. In FIG. 16 (2), the amount of the belt 6 riding on the frusto-conical contact surface 122 was 4.29 to 5.00 mm. Therefore, in the embodiment of the present invention, even if toner and oil adhere to the contact surface 122 of the meandering detection member 120 and the temperature load is further increased, the meandering amount of the belt 6 is smaller than that of the comparative example 1. It was confirmed that.

The meandering detection member 120 is made of a polyamide-imide resin.
Even during the continuous operation for 200 hours, the belt 6 did not crack and the contact surface 122 was hardly worn. Accordingly, it was confirmed that the meandering detection member made of a polyamideimide-based resin had excellent wear resistance. When the meandering detection member 120 was made of a PPS (polyphenylene sulfide) -based synthetic resin, the contact surface 122 suffered 1.5 mm bite abrasion during continuous operation for 150 hours. In another embodiment of the invention, the contact surface 12
2 is provided on the meandering detection member main body, and only this contact portion is made of a polyamide-imide synthetic resin. The detection member main body is made of another material, for example, an inexpensive PPS resin having little sliding friction. And the like.

In the above-described embodiment, the meandering amount of the belt 6 can be reduced, the life of the belt 6 can be prolonged, and chatter, which is a minute vibration of the belt 6, is not observed. 6 has relatively low tension,
The meandering of the belt 6 was sufficiently suppressed, and the vehicle could run stably.

FIG. 17 is a sectional view of a part of still another embodiment of the present invention. This configuration is similar to the configuration described with reference to FIG. In this embodiment,
The bearing 6 has rolling contact portions 184 and 185 which are concave portions.
Are formed, and rolling receiving portions 186 and 187 which are convex portions are formed on the parallel portion 156 of the support member 45. In a state where the belt 6 does not meander, the rolling contact portion 1
84 abuts against the rolling receiving portion 186, and the bearing 6 is moved by the spring force of the meandering detection spring 127 to move the bearing 6 to the upper end portion 14 of the guide slot 50.
3 is in contact.

When the belt 6 meanders and its side end contacts the belt contact surface 122, as shown in FIG. 17, the rolling contact portions 184, 185 become the rolling receiving portions 186, 1
The rollers 87 are in contact with each other and are rolled and displaced, so that the rolling contact portions 185 are received by the rolling receiving portions 187. A low ridge 188 is formed between the rolling contacts 184,185. Rolling receiving parts 186, 18
7, a recess 189 that does not contact the raised portion 188 is formed. The rolling contact portions 184, 1 in FIG.
The distance between 85 and the distance between the receiving portions 186 and 187 are equal. Other configurations in the embodiment of FIG. 17 are the same as those in the embodiment of FIGS.

FIG. 18 is a perspective view of a sliding bearing 193 according to another embodiment of the present invention. The configuration for supporting the shaft end 24 of the heating roller 5 using the bearing 193 is shown in FIG. 19 corresponding to FIG. 1 described above, and FIG.
0, and the left side surface of the belt fixing device having the configuration shown in FIGS. 18 to 20 is shown in FIG. Other configurations are the same as those of the above-described embodiment of FIGS. 1 to 16, and may be configured as shown in FIG. 22.

In the embodiment shown in FIGS. 18 to 21, the bearing 26 is made of synthetic resin in the same manner as the bearing 26 described above, and may be formed by injection molding. The bearing 193 has displacement guides 194 and 195, and has flanges 196 and 197 disposed outside the support member 45 in the axial direction. On the axially inner side of the displacement guides 194 and 195, a holding portion 162 is connected, and further, a flange portion 163 having an inclined frustoconical surface 165 is provided. Displacement guides 194, 195
21 are slidably guided by vertically extending guide surfaces 199 and 200 in FIG. 21 of the displacement guide holes 198 formed in the support member 45. Displacement guides 194, 195
Are formed to be elongated, and guide surfaces 199,
200, the sliding bearing 193
However, the sliding bearing 193 is not angularly displaced around the axis of the shaft end 24, and therefore, there is no possibility that the sliding bearing 193 will be worn. Other configurations are the same as those shown in FIGS.
This is the same as the embodiment described in connection with No. 6.

FIG. 22 is a partial sectional view of another embodiment of the present invention. This embodiment is described in FIGS.
6 and FIGS. 17 to 21, and corresponding parts are denoted by the same reference numerals. The belt meandering preventing means 63 is the side plate 1 in the embodiment of FIGS.
5, the belt meandering preventing means 63a is provided on the side plate 1 in FIG.
Four sides are provided. The guide long hole 50 that supports the bearing 25 is formed in the support member 73 that forms the lid 71. Both ends 128 and 129 of the meandering detection spring 127 are connected to the support member 73. One end of the cable 132 is connected to the meandering detection member 120 as described above, and the other end 13 is connected.
5 is connected to the support member 73. Thus, in the embodiment of FIG. 22, the belt meandering preventing means 63a is provided inside the side plate 14 (left side in FIGS. 3 and 4) and near the side plate 14. Therefore, when the belt 6 is replaced, the belt meandering detection device 63a provided near the lid 71 can be easily inspected, and the meandering detection member 120 can be removed from the retaining rings 80, 81, and 138. Can be easily replaced.

In still another embodiment of the present invention, the shaft end portion 24 of the heating roller 5 is provided with the belt meandering preventing means 63 described above with reference to FIGS. The part 23 is provided with the belt meandering prevention means 63a described in relation to FIG.
The belt meandering preventing means 63, 63a may be provided in each of 4, 4 and 23. In this embodiment, the meandering detecting members 1 provided at the respective shaft ends 24 and 23 are provided.
The distance between the contact surfaces 122 along the rotation axis is set to be substantially equal to the width of the belt 6 at a normal temperature where the fixing operation is not performed. At the time of fixing, the heating roller 5 is, for example, about 1
When the temperature is raised to 60 to about 200 ° C., the heating roller 5 thermally expands and expands, for example, 1.5 to 2.0 mm.
Although the elongation creates a gap between the side edge of the belt and the contact surface 122, the gap is relatively small. Therefore, even in the embodiment in which the belt meandering preventing means 63 and 63a are provided on both shaft ends 24 and 23, meandering of the belt can be prevented with high accuracy.

FIG. 23 is a diagram schematically showing the operation principle of the belt meandering preventing means 63. In FIG. 23, a pressure roller 7 is provided between the fixing roller 3 and the heating roller 5.
The general configuration pressed against the belt 6 is shown. Such a configuration is included in an embodiment of the present invention. When the pressure roller 7 comes into contact with the portion of the belt 6 wound around the outer peripheral surface of the fixing roller 3, the entrance end 204 is on the outer peripheral surface of the fixing roller 3. Axis 201 of heating roller 5
However, the direction 177 in which the belt is displaced in order to prevent meandering is
The axis 20 when the meandering of the ellipse 205 does not occur
It corresponds to the tangential direction at position 1. The ellipse 205 is
It has an outlet end 203 of the fixing roller 3 and an inlet end 204 of the belt 6 of the pressure roller 7 as centers. In this ellipse 205, the distance g between the axis 201 and the outlet end 203 in a state where the belt of the heating roller 5 does not meander.
And the distance h between the axis 201 and the entrance end 204 (= g + h) are constant. Shaft end 24 of heating roller 5
In displacing the and / or 23 to prevent the belt from meandering, the shaft ends 24 and / or 23 can be displaced so that a component along the displacement direction 177 is generated.

The meandering preventing means 63, 63a of the belt 6
In addition to being provided in connection with the heating roller 5, it may be provided in connection with other belt conveyance rollers, that is, in connection with a tension roller in which a heat source is not used. Further, the heat source may not be provided so as to pass through the belt transport roller. For example, the heat source is provided so as to be stretched between the two rollers 3 and 5 and to heat a stretched portion facing the pressure roller 7. You may be.

The bearings 19, 20; 31, 32 may be not only rolling bearings but also sliding bearings similar to those described above.

[0109]

According to the first aspect of the present invention, since the shaft end of one belt conveying roller provided with the meandering preventing means is supported by the slide bearing, the above-mentioned rolling bearing such as the ball bearing is used. The configuration is simplified compared to the configuration.

In addition, according to the present invention, the sliding bearing has a rolling contact portion, and the rolling contact portion is received by the rolling receiving portion. Therefore, the rolling friction coefficient is small, and therefore, the meandering belt can detect the meandering. The meandering detection member, that is, the shaft end of the one belt conveyance roller can be reliably displaced in the predetermined displacement direction by a small torque generated when the belt contact portion of the member comes into contact. Therefore, meandering of the belt can be prevented with high accuracy.

According to the second aspect of the present invention, the meandering preventing means is provided only at one shaft end of the one belt conveying roller, and the sliding bearing is provided on one of the supporting members by the rolling friction. And the other shaft end is also supported by the other support member by another slide bearing, so that the two support members 45 and 73 are spring-loaded by the belt tensioning spring, and the belt is tensioned. , The meandering of the belt can be reliably prevented while applying an optimum tension suitable for fixing to the belt, and thus the quality of the belt fixing can be improved.

According to the third aspect of the present invention, since the rolling contact portion and the receiving portion are composed of a plurality of convex portions or concave portions, the configuration can be simplified, and the sliding bearing can be formed of a belt. Since the sliding bearing is not configured to make a sliding contact to prevent meandering, wear of the sliding bearing can be prevented, and a long life can be achieved.

According to the fourth aspect of the present invention, since the rolling contact portion and the receiving portion are disposed on the side of the sliding bearing in the direction of the belt reaction force, regardless of the magnitude of the tension applied to the belt, The rolling contact portion of the slide bearing can reliably cause the rolling receiving portion to displace the shaft end in the predetermined displacement direction when the belt meanders due to rolling friction.

According to the fifth aspect of the present invention, a pair of flange portions 161 and 163 are formed on the slide bearing, and sandwich the meandering detection spring 127 and the one support member 45, thus forming the one belt. The displacement of the transport roller in the axial direction can be easily prevented. Therefore, even if the belt transport roller thermally expands, the position of the belt on the one shaft end side does not change, and the meandering of the belt can be reliably prevented regardless of the thermal expansion of the belt transport roller.

According to the sixth aspect of the present invention, the displacement guide portion of the slide bearing is fitted into a displacement guide hole formed in the fixing device main body side, that is, a support member or a side plate of the fixing device main body, so that the sliding displacement is achieved. This makes it possible to prevent the displacement of the sliding bearing around the axis, thereby simplifying the configuration and reducing the cost by using the sliding bearing, and also preventing wear of the sliding bearing and extending the service life. It can be.

According to the seventh aspect of the present invention, the contact surface 122 formed on the belt contact portion of the meandering detecting member is aligned with the axis of the belt conveying roller on which the meandering detecting member is supported. Because it is almost vertical, foreign substances such as toner and oil adhere to the contact surface,
Even if the coefficient of friction with the side end of the belt fluctuates due to the temperature load during fixing, the meandering of the belt can be prevented with high accuracy. Moreover, even if the belt-side end contacts the contact surface, cracks are unlikely to occur, and the life of the belt is extended.

The angle θ1 of the contact surface is set to be about 70 to about 90 degrees, so that it is possible to prevent the belt from meandering, to achieve accurate position regulation, and to prevent the belt from cracking. And a longer life.

According to the eighth aspect of the present invention, there is provided a means for preventing the belt from meandering in relation to the heating roller, instead of using the tension roller provided with the mechanism for preventing the belt from meandering as described in relation to the prior art. Is provided, whereby the structure can be reduced in size, and thus the cost can be reduced. Further, since the tension roller is not used as described above, heat loss is correspondingly reduced, and an energy saving effect is achieved.

Further, in the present invention, since the tension roller is not used as described above, the circumferential contact angle of the heating roller with which the belt is wound and comes into contact with the heating roller can be increased. Thereby, heat conduction from the heating roller to the belt can be favorably performed. Therefore, the heating time can be shortened and the energy saving effect can be improved. In this way, belt meandering control is achieved without impairing the belt fixing characteristics, that is, the offset phenomenon in which toner adheres to the belt is less likely to occur, and the fixing nip width is increased to improve the fixing quality. .

Further, since means for preventing the meandering of the belt is provided in connection with the heating roller, the above-described tension roller is not used, the number of parts is reduced, and the productivity is improved. Further, since no heat absorbing and radiating parts such as a tension roller contacting the belt are provided, heat loss is reduced. Further, according to the present invention, it is possible to extend the life of the belt used at high temperatures without having to perform processing for preventing the belt from meandering.

According to the belt meandering prevention device of the ninth aspect, the structure can be simplified by using a sliding bearing, and the displacement in the predetermined displacement direction for preventing the belt meandering can be controlled by the sliding bearing. Since the displacement is achieved by the displacement due to rolling friction, the displacement of the shaft end in the predetermined displacement direction can be obtained with a small torque acting on the meandering detection member due to the frictional contact between the belt and the belt contact portion, and the belt Meandering can be prevented with high precision.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of a part of a belt fixing device 1 according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the configuration shown in FIG.

3 is a horizontal sectional view of the remaining part of the belt fixing device 1. FIG.

FIG. 4 is a longitudinal sectional view of the configuration shown in FIG. 3;

FIG. 5 is a simplified longitudinal sectional view of the belt fixing device 1.

FIG. 6 is a left side view of the fixing device main body 2.

FIG. 7 is a perspective view of a bearing 26 and its vicinity.

FIG. 8 is an exploded perspective view of the vicinity of a left side plate 15 of the fixing device main body 2.

9 is an exploded perspective view of the vicinity of a support member 45. FIG.

FIG. 10 is a simplified perspective view showing a heating roller 5 and a part of a configuration related thereto.

11 is a right side view of the belt fixing device 1. FIG.

FIG. 12 is an exploded perspective view of a side plate 14 of the fixing device main body 2 and its vicinity.

FIG. 13 is a simplified diagram showing a state in which a belt 6 is wound around a fixing roller 3 and a heating roller 5.

FIG. 14 is a partial cross-sectional view showing a state in which the bearing 26 is supported in the guide slot 50 so as to be able to come into rolling contact therewith.

FIG. 15 illustrates a meandering detection member 120 according to an experiment performed by the present inventor.
FIG. 6 is a diagram showing a relationship between the angle θ1 of the belt contact surface 122 of FIG.

FIG. 14 (1) shows the meandering amount of the belt 6 with the passage of time in the example of Table 1 and FIG. 14 (2)
FIG. 9 is a diagram illustrating a meandering amount of a belt 6 of Comparative Example 1 during a fixing operation.

FIG. 17 is a partial cross-sectional view of still another embodiment of the present invention.

FIG. 18 is a plain bearing 193 according to another embodiment of the present invention.
It is a perspective view of.

19 is a horizontal sectional view of a part of the belt fixing device 1 using the sliding bearing 193 shown in FIG.

20 is a longitudinal sectional view of the belt fixing device 1 according to the embodiment of the present invention shown in FIGS. 18 and 19. FIG.

FIG. 21 is a belt fixing device 1 shown in FIGS.
3 is a left side view of the fixing device main body 2 of FIG.

FIG. 22 is a partial cross-sectional view of another embodiment of the present invention.

FIG. 23 is a diagram showing a simplified operation principle of the belt meandering prevention means 63;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Belt fixing device 2 Fixing device main body 3 Fixing roller 4 Heat source 5 Heating roller 6 Endless belt 7 Pressure roller 8 Recording paper 14,15 Side plate 17,18,23,24,31,32 Shaft end 19,20,25 , 26,33,34 Bearings 21,53,54,80,81,103,106,10
7 Retaining Ring 22 Drive Gear 36 Pressure Spring 42, 43, 50, 67 Guide Slot 45, 73 Supporting Member 51, 68, 100, 101, 104 Outer Ring 52, 69, 102, 105 Inner Ring 55, 82 Belt Tension Spring 63, 63a belt meandering prevention means 64, 65, 67, 97 opening 66 insertion / removal hole 68 connection hole 71 lid 72 auxiliary plate 120 meandering detection member 121, 123 belt guide part 122 contact surface 125 cable guide part 126 flange 127 meandering detection Spring 132 Cable 139 Displacement limiting member 140 Roller support means 141 Roller shaft end displacement means 161, 163, 166 Flange 162 Holder 167 Guide 178, 179; 184, 185 Rolling contact 181, 182; 186, 187 Rolling receiving part 175 Belt reaction force 194,195 Displacement guide part 198 displacement guide hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H033 BA11 BB37 BE03 CA01 CA35 3F023 AA05 BA02 BB05 BC01 CA02 GA03 3F033 GA02 GB04 GE06 LA05 3F104 AA00 CA11 CA35

Claims (9)

[Claims] 1. An endless belt, a plurality of belt transport rollers around which the belt is wound and rotatably supporting the belt, a heat source for heating the belt, and a recording paper having a toner image sandwiched between the belt. A belt-fixing device including a pressure roller that transports the belt by at least one of the belt transport rollers, wherein at least one of the shaft ends is provided with a meandering preventing unit that prevents belt meandering; A meandering detection member 120 having a belt contact portion 123 that is rotatably supported on at least one shaft end of the roller and that is rotatable with respect to the shaft end, and that contacts the belt; and the shaft end that supports the meandering detection member. A roller supporting means 140 for supporting the belt in such a manner that it can be displaced in a predetermined displacement direction perpendicular to the axis of the belt conveying roller; And a roller shaft end displacement means 141 for displacing the shaft end supporting the meandering detection member of the belt conveyance roller in the predetermined displacement direction when torque is applied by contact of the belt with the roller. The support means 140 rotatably supports the shaft end portion, and has a sliding bearing 26 having a rolling contact portion on the outer peripheral portion in a rolling contact with the predetermined displacement direction, and a sliding bearing rolling the rolling contact portion. A belt fixing device having a rolling receiving portion that receives a displacement in a predetermined displacement direction. 2. The meandering preventing means is provided only at one shaft end of the one belt transport roller, has a rolling receiving portion, and moves the one belt transport roller in a direction of applying belt tension. One support member 45 movably provided on the fixing device main body, another slide bearing rotatably supporting the other shaft end of the one belt transport roller, and the other slide bearing. The other support member 73 provided on the fixing device main body and the one support member 45 and the other support member 73 so as to support and move the one belt conveyance roller in a direction of applying belt tension. The belt fixing device according to claim 1, further comprising a belt tension applying spring for applying a belt tension. 3. The rolling contact portion is one of a plurality of convex portions or concave portions provided at intervals in the predetermined displacement direction, and the rolling receiving portion is spaced apart in the predetermined displacement direction. 2. The belt fixing device according to claim 1, wherein the belt fixing device is one of a plurality of convex portions and concave portions provided in the manner. 4. The rolling contact portion and the receiving portion,
The belt fixing device according to claim 1, wherein the belt fixing device is disposed on a side of the slide bearing in a belt reaction force direction. 5. A meandering detection spring, which partially surrounds the sliding bearing in a circumferential direction and applies a spring force in a direction opposite to the predetermined displacement direction, is provided on the one supporting member. A pair of flanges 161 and 163 sandwiching the meandering detection spring and the one support member are formed, and the one support member is provided on the fixing device body in the axial direction of the one belt conveyance roller. The displacement is prevented, and the other slide bearing or the other support member is supported by the fixing device main body such that the one belt conveyance roller can be displaced in the axial direction. Item 3. A belt fixing device according to Item 2. 6. An endless belt, a plurality of belt transport rollers around which the belt is wound and rotatably supporting the belt, a heat source for heating the belt, and a recording paper having a toner image sandwiched between the belt. A belt-fixing device including a pressure roller that transports the belt by at least one of the belt transport rollers, wherein at least one of the shaft ends is provided with a meandering preventing unit that prevents belt meandering; A meandering detection member 120 having a belt contact portion 123 that is rotatably supported on at least one shaft end of the roller and that is rotatable with respect to the shaft end, and that contacts the belt; and the shaft end that supports the meandering detection member. A roller supporting means 140 for supporting the belt in such a manner that it can be displaced in a predetermined displacement direction perpendicular to the axis of the belt conveying roller; And a roller shaft end displacement means 141 for displacing the shaft end supporting the meandering detection member of the belt transport roller in the predetermined displacement direction when torque is applied by contact of the belt with the roller. The support means 140 rotatably supports the shaft end portion, and has a slide bearing having a displacement guide portion extending in parallel with the predetermined displacement direction on the outer peripheral portion. The displacement guide portion is provided on the fixing device main body side. A belt fixing device formed and fitted in a displacement guide hole extending in parallel with the predetermined displacement direction and capable of sliding displacement. 7. The meandering detection member includes a belt contact portion 123,
The belt fixing device according to claim 1, further comprising a contact surface that faces the belt and is substantially perpendicular to the rotation axis. 8. The apparatus according to claim 1, wherein the one belt conveying roller is a heating roller provided with a heat source.
The belt fixing device according to any one of claims 1 to 7. 9. An endless belt, a plurality of belt transport rollers around which the belt is wound and rotatably supporting the belt, and a belt meandering at least one shaft end of one of the belt transport rollers is prevented. Meandering prevention means is provided, and the meandering prevention means is a meandering detection member having a belt contact portion 123 supported on at least one shaft end of the belt transport roller so as to be rotatable relative to the shaft end and in contact with the belt. 120, a roller supporting means 140 for supporting the shaft end supporting the meandering detection member in a predetermined displacement direction orthogonal to the axis of the belt transport roller, and a roller supporting means 140. The roller meandering member is connected to the meandering detection member. When the belt is brought into contact with the belt contact portion and torque is applied, the shaft end supporting the meandering detection member of the belt transport roller is moved in the predetermined displacement direction, And a roller shaft end displacing means 141 for displacing, the roller supporting means 140 rotatably supporting the shaft end, and a sliding bearing having a rolling contact portion on an outer peripheral portion in rolling contact with the predetermined displacement direction. A belt meandering prevention device, comprising: a rolling contact portion that receives a rolling contact portion so that the sliding bearing rolls and is displaced in the predetermined displacement direction.