JP2000075699A - Belt fixing device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the configuration, reduce heat loss, and prevent meandering of fixing belt 6. SOLUTION: A belt 6 is wound around a fixing roller 3 and a heating roller 5, and a pressure roller 7 is pressed against the fixing roller via the belt. A meandering detection member 120 is rotatably supported on one shaft end of the heating roller, and the one shaft end 24 is supported by a support member 45 so as to be vertically displaceable. When the belt meanders and comes into contact with the belt contact portion 123 of the meandering detection member, the rope 132 is wound around the rope guide portion 125 against the spring force of the meandering detection spring 127, and the one shaft end 24 is moved. Displacement, thus preventing belt meandering. A support member 45 for supporting both shaft ends of the heating roller,
The belt tension applying springs 55 and 82 are connected to 73.

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 used 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, since a tension roller provided with a means for preventing the belt from meandering is used, the configuration is large, and the cost is not reduced. In addition, by using a tension roller having a configuration to prevent the belt from meandering, heat of the belt is absorbed by the tension roller, and heat is radiated by the tension roller. Therefore, the belt is efficiently maintained at a temperature suitable for fixing. And requires much time and energy for heating. In addition, a hollow heating roller with a heat source inserted,
In the configuration in which the belt is wound, by using the above-described tension roller, the circumferential contact angle of the belt wound around the heating roller is reduced. This also increases the heating time of the belt and reduces the energy saving effect.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a belt fixing device which has a reduced size, is excellent in cost reduction, has a small heat loss, and has an improved energy saving effect.

[0005]

According to the present invention, an endless belt is wound around a plurality of rollers including a heating roller provided with a heat source, and a recording medium having a toner image between the belt and a pressure roller. A belt fixing device characterized in that paper is nipped and conveyed, and a heating roller is provided with meandering preventing means for preventing meandering of the belt.

According to the present invention, an endless belt for fixing is wound around a plurality of rollers including a heating roller, and a recording paper having a toner image is formed between an outer peripheral surface of the belt and a pressing roller. The toner is heated and melted by being sandwiched and fixed to the recording paper, and thereafter, the recording paper is peeled off from the belt to perform fixing.

[0007] In particular, in the present invention, in connection with the heating roller,
Since the belt meandering prevention means is provided, it is easy to reduce the overall configuration of the belt fixing device, and therefore it is excellent in cost reduction, and furthermore, heat loss is reduced and energy saving effect is improved. Is easily possible.

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. 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.

Further, according to the present invention, the meandering preventing means is provided at at least one shaft end of the heating roller so as to be rotatable with respect to the shaft end, and to contact the belt.
3 and a roller supporting means 14 for supporting the shaft end supporting the meandering detecting member in a predetermined displacement direction perpendicular to the axis of the heating roller.
0, the shaft end supporting the meandering detection member of the heating roller when the belt is in contact with the meandering detection member and the belt contacts the belt contact portion of the meandering detection member and torque is applied. And a roller shaft end displacement means 141 for displacement.

The meandering preventing means according to the present invention includes a meandering detecting member, a roller support means, and a roller shaft end displacement means, and prevents meandering of the belt. The function of preventing the belt from meandering will be described. 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 detection member, and thus the meandering preventing means, may be supported on both ends of the heating roller, or may be supported only on one of the ends.

Further, according to the present invention, the heating roller is disposed upstream of the remaining rollers other than the heating roller in the conveying direction of the recording paper in the conveyance path of the recording paper, and one of the remaining rollers is provided. One is a fixing roller, and the fixing roller is provided on the fixing device main body so as to be rotatable with the position of the rotation axis fixed, and is rotationally driven by a driving unit, and the pressure roller is fixed to the fixing device main body. The roller is provided so as to be displaceable in the radial direction of the roller, and a spring is applied to the pressure roller by a pressure spring toward the fixing roller via a belt, and at least one of the shafts supporting a meandering detection member of the heating roller The end is provided on the fixing device main body so as to be displaceable in the predetermined displacement direction, which is a circumferential direction about the rotation axis of the fixing roller, and to be displaceable in the radial direction of the fixing roller. Both axial ends of the rollers by a belt tensioning spring, mow the direction of the spring force far removed by the radially fixing roller of the fixing roller is equal to or given.

According to the present invention, among the plurality of rollers around which the belt is wound, the heating roller is disposed at the most upstream side in the conveying direction of the recording paper in the conveying path, and the recording paper is heated by the heating roller. The toner forming the toner image is heated and melted by being brought into contact with the belt and conveyed together with the belt. When the recording paper is transported,
Next, the toner is sufficiently cooled, and then the recording paper is peeled from the belt.

A pressure roller is pressed by a pressure spring toward the fixing roller around which the belt is wound downstream of the heating roller in the transport direction. The recording paper is nipped and conveyed between the belt and the pressure roller. As described above, the pressure roller is provided with the spring force directed toward the fixing roller by the pressure spring, so that the recording sheet can be sandwiched between the pressure roller and the belt with a relatively large spring force. . As a result, the heat conduction between the belt and the recording paper is ensured, the mutual deviation between the recording paper and the belt is eliminated, and the fixing quality is improved. Moreover, a large tensile force by the pressure spring does not act on the belt, and the life of the belt is extended. In this way, the recording paper is sandwiched between the belt and the pressure roller, and the belt and the recording paper are conveyed while maintaining stable surface contact with both the belt and the recording paper without sagging or deforming. Thereafter, the recording paper is peeled from the outer surface of the belt.

The heating roller is provided with a spring force in a direction away from the fixing roller in a radial direction of the fixing roller by belt tension applying springs provided at both shaft ends thereof. An appropriate value of tension independent of the force will be applied to the belt.

According to the present invention, the fixing device main body includes a fixing roller and a pressure roller that are rotatably supported, and both ends of the heating roller are attached to the fixing roller in order to apply tension to the belt. Are respectively provided in the fixing device main body so as to be movable in the radial direction of the fixing roller, that is, can be moved close to and away from the fixing roller, and both shaft ends are fixed to the fixing roller by belt tension applying springs 55 and 82. Is applied radially outward, that is, in a direction in which the heating roller moves away from the fixing roller.

When the meandering of the belt occurs, the meandering detecting member has a component in a direction perpendicular to the axis of the heating roller,
Displace. Thus, it is possible to reduce the heat loss, to increase the contact angle of the belt with the heating roller, and to apply tension to the belt without using a tension roller.

The basic idea of the present invention is that a fixing roller which is rotationally driven by a driving means is provided on a fixing device main body at a fixed position of a rotation axis of the fixing roller. Based on the position, the pressure roller is pressed against the fixing roller via the belt by the pressure spring as described above, and the heating roller has a spring in a direction away from the fixing roller in a radial direction of the fixing roller. A force is applied to tension the belt. Since the position of the rotation axis of the fixing roller is fixed as described above, the fixing roller can be driven to rotate stably by the driving unit. In addition, the pressure roller can be pressed against the fixing roller with a relatively large spring force by the pressure spring, and an appropriate tension can be applied to the belt as described above. In addition, a meandering detection member is provided at at least one shaft end of the heating roller to realize a configuration in which the shaft end can be displaced in the predetermined displacement direction. The position of the rotation axis is fixed, and stable rotation is achieved.

Further, the present invention is characterized in that the belt is wound around only a heating roller and another roller among the rollers.

According to the present invention, the plurality of rollers around which the belt is wound include a heating roller and another roller,
For example, there are a total of two fixing rollers. As a result, the tension roller described in connection with the above-mentioned prior art is not used, so that the structure can be reduced in size, cost can be reduced, heat loss can be reduced, and the belt can be wound around the heating roller. The contact angle in the circumferential direction of the heat roller contacting the heat roller can be increased so that heat transfer from the heat roller to the belt can be performed well, thereby shortening the heating time and improving the energy saving effect. .

Further, the time from when the power is turned on to when the temperature of the belt rises to a temperature suitable for fusing the toner and fixing becomes possible can be shortened.

Further, according to the present invention, the shaft ends 24 and 23 supporting the meandering detecting member of the heating roller have an outer diameter smaller than the belt guide portion 121 around which the belt of the heating roller is wound. However, the meandering detection member is inserted coaxially.

According to the present invention, the meandering detecting member includes the shaft ends 24 (FIG. 1) and 23 (FIG. 10) having an outer diameter smaller than the outer diameter of the belt guide portion 121 of the heating roller. The meandering detection member is supported so as to be rotatable about the axis of the member and mutually rotatable, thereby simplifying the configuration.

If the axially outer end of the shaft end is supported by a support member via bearings 26 and 25 and the heating roller is rotatably supported, maintenance can be simplified. Can be.

Further, according to the present invention, the roller supporting means rotatably supports both ends of the heating roller so as to be rotatable in a radial direction of the fixing roller. 73, the predetermined displacement direction of the shaft end supporting the meandering detection member of the heating roller is a direction orthogonal to the moving direction of the support member, and the belt tension applying spring 55 is attached to each support member. , 82 apply a spring force outward of the fixing roller in the radial direction.

According to the present invention, the roller supporting means provided in the meandering preventing means has a pair of supporting members 45 and 73, and each supporting member rotatably supports each shaft end of the heating roller. These support members are pulled or compressed radially outward of the fixing roller by belt tension applying springs 55 and 82 to apply a spring force to apply tension to the belt. In order to prevent the belt from meandering, shaft ends supporting the meandering detection member of the heating roller are provided on the support members 45 (FIG. 1) and 73 (FIG. 10), and the shaft ends are moved by the support member. This is a direction orthogonal to the direction (ie, the radial direction of the fixing roller), in other words, the shaft end is a circumferential direction centered on the rotation axis of the fixing roller.
As described above, the belt is prevented from meandering by displacing the heating roller in a direction orthogonal to the moving direction of the support member. In this way, the belt tension applying spring applies spring force to the heating roller via the supporting member to apply tension to the belt, and applies the shaft end of the heating roller to the supporting member in the moving direction of the supporting member. The belt can be supported so as to be displaceable in a direction perpendicular to the belt, and meandering of the belt can be prevented.

In one embodiment of the present invention, the heating roller is hollow, a heat source is inserted through the heating roller, and the heat source is fixed to a support member. According to this configuration, the heat source 4 through which the heating roller is inserted is fixed to the support member. The heat source may be realized, for example, by an elongated halogen lamp, with both ends of the elongated heat source fixed to the support member 45 as described above. As a result, the heat source is displaced together with the support member on which the heating roller is supported as described above, and thus the relative displacement between the heating roller and the heat source substantially coaxial with the heating roller is kept substantially constant, and the supporting member is displaced. It can be moved to apply tension to the belt. The amount of displacement of the heating roller by the roller shaft end displacement means for preventing meandering of the belt is negligible, so that the relative displacement between the heating roller and the heat source is kept substantially constant as described above. Therefore, the outer peripheral surface of the heating roller can be heated with a substantially uniform temperature distribution over the entire length of the belt guide portion in the axial direction, and thus the belt can be heated with a uniform temperature distribution over the width direction.

Further, the present invention is characterized in that it includes means 89 for adjusting at least one spring force of the belt tension applying spring.

According to the present invention, the meandering of the belt can be further suppressed by adjusting the spring force of at least one of the belt tension applying springs. Therefore, it is possible to eliminate the disadvantage that the heating roller vibrates due to the operations of the meandering of the belt and the correction thereof.

According to the present invention, the roller shaft end displacement means is provided on the cable guide portion 125 formed axially outward of the belt contact portion 123 of the meandering detection member and the support member 45, and is provided with the heating roller. The shaft end 2 supporting the meandering detection member
4, a meandering detection spring 127 that applies a meandering detection spring force in one direction orthogonal to the direction of movement of the support member, one end is fixed to the cable guide portion, and the other end is fixed to the support member. When the belt comes into contact with the belt contact portion and a torque is applied, the rope is wound around the rope guide in the direction in which it is wound, against the meandering detection spring force, whereby the shaft is rotated. A rope 132 whose end is displaced in the other direction perpendicular to the direction of movement of the support member and opposite to the one direction.
And characterized in that:

According to the present invention, when the belt is brought into contact with the belt contact portion of the meandering detecting member and torque is applied, the cable becomes
It winds around the cable guide part 125. As a result, the shaft end 24 supporting the meandering detection member of the heating roller is
Is displaced in the predetermined displacement direction near the other end 135, that is, the shaft end is displaced in the other direction (downward in FIG. 5) orthogonal to the moving direction of the support member. This corrects the meandering of the belt. The shaft end 2 of the heating roller
The spring force 4 is applied by the meandering detection spring 127 in the one direction (upper direction in FIG. 5) orthogonal to the moving direction of the support member, which is opposite to the predetermined displacement direction. Therefore, in a state where the belt is wound around the belt guide portion of the heating roller, the belt contacts the meandering detection spring force and the inner circumferential surface of the belt and the inner circumferential surface thereof without or in contact with the meandering detecting member. The belt can travel without meandering at a position where equilibrium in the width direction of the belt is obtained due to frictional force with the outer peripheral surface of the meandering detection member or the like.

[0032]

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 a line III-III in FIG.
FIG. 4 is a cross-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 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, the side plate 14 has an insertion / removal hole 66 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 bearings 25 and 26.

FIG. 6 is a left side view of the fixing device body 2.
FIG. 7 is an exploded perspective view of the vicinity of the side plate 15. The shaft end 31 (see FIG. 11 described later) and the shaft end 32 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 the 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 provided with a spring force toward the fixing roller 3, and the pressing roller 7 is pressed against the belt 6. 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
The oval guide elongated hole 42 extending vertically is formed in the
Similarly, the vertical displacement of the bearing 34 is allowed,
A guide slot 43 is formed in the side plate 15 as shown in FIG.
Bearings 33 and 34 are fitted and guided in these guide slots 42 and 43. Shaft ends 31 and 3 of pressure roller 7
2 is smaller than the outer diameter of the pressure roller body to which the belt 6 is pressed and smaller than the outer diameter of the bearings 33 and 34, and can be removed from the insertion / removal 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 has guide portions 48 and 49 which are detachably fixed to the side plate 15 by mounting bolts 118 and form guide grooves for guiding the upper and lower side portions of the support member 45 with the side plate 15.

The support member 45 is formed with an oval guide elongated hole 50 which is elongated in the vertical direction perpendicular to the radial direction of the fixing roller 3. The guide slot 50 has a heating roller 5
The outer ring 51 of the bearing 26 that supports the shaft end 24 is disposed. The shaft end 24 is inserted through the inner ring 52 of the bearing 26. A rolling element 44 is interposed between the outer ring 51 and the inner ring 52. On the outer side of the support member 45, that is, on the side opposite to the side plate 15 (left side in FIGS. 1 and 2), a retaining ring 53 can be elastically removed from an annular groove formed in the outer ring 51 of the bearing 26. And the axial end 24 of the outer ring 51 and thus the bearing 26 inward in the axial direction (to the right in FIGS. 1 and 2).
Is prevented from being displaced. The shaft end 24 of the heating roller 5 is also provided with an annular groove into which a retaining ring 54 is resiliently and removably fitted so that the shaft end 24 is axially inward (FIGS. 1 and 4). 2 is prevented.

FIG. 8 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 end plate 24 of the heating roller 5 is provided on the side plate 15.
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. 9 is a simplified perspective view showing the structure of the heating roller 5 and a part related thereto, FIG. 10 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. Side plate 1
4, an insertion 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 is formed. Further, an opening 67 connected to the insertion / removal hole 66 is formed in the side plate 14. The opening 67 extends in a direction away from the fixing roller 3 with respect to the heating roller 5. The guide elongated hole 42 is connected to and connected to the insertion / removal hole 66 via the connection hole 68. The width W1 of the connection hole 68 (see FIG. 10) is equal to or greater than the outer diameter D1 of the shaft end 31 of the pressure roller 7 (W1 ≧ D1). Therefore, in a state where the bearing 33 is not fitted into the guide elongated hole 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 determined to be equal to or less than the vertical interval of the insertion / removal 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.

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

Bearings 19, 20; 25, 26 and 33,
Numeral 34 denotes a rolling bearing, whose rolling elements 44, 75,
Each of 116 and 117 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 (to the right in FIG. 3 and to the right in FIG. 11), a lid 71 for closing the insertion / removal hole 66 and the opening 67 and partially closing the connection hole 68 is provided. Lid 71
Includes an auxiliary plate 72 and a support member 73. Auxiliary plate 72
A bolt insertion hole through which a plurality of (for example, four) bolts 74 are inserted is formed. The bolt 74 is detachably screwed into a screw hole 76 formed in the side plate 14. 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 has an outer ring 78, an inner ring 79, and a rolling element 75 interposed therebetween. Support member 73
3 and 4, a retaining ring 80 is removably fitted to the outer ring 78, whereby the outer ring 78,
Therefore, the bearing 25 is prevented from displacing in the axial direction of the heating roller 5 (to the left in FIGS. 3 and 4). A retaining ring 81 is detachably fitted to the shaft end 23 of the heating roller 5 outside the support member 73 than the inner ring 79. This prevents the shaft end 23 from being displaced inward in the axial direction (leftward in FIG. 3).

The outer ring 28 of the bearing 25 loosely penetrates through the through hole 142 formed in the support member 73 and loosely fits.
That is, there is a slight gap between the outer diameter of the outer ring 78 and the inner diameter of the play hole 142. This allows the shaft end portion 24 of the heating roller 5 to be displaced along the guide slot 50 by the action of the belt meandering preventing means 63 to incline the axis of the heating roller 5, and the belt tension applying spring 55,
The function of 82 allows the axis of the heating roller 5 to be inclined.

With respect to the inner ring 79 of the bearing 25 and the shaft end 23 of the heating roller 5, the shaft end 23 gently penetrates the inner ring 79 so that mutual displacement is allowed along the axis of the heating roller 5. 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. For this reason, the axial end 24 is prevented from displacing the outer ring 52 of the bearing 26 along the axial direction of the heating roller 5 by the retaining ring 54 and a retaining ring 138 described later. 48, 49, the support member 45
The displacement of the side plate 15 and the heating roller 5 along the axial direction is prevented. Further, the outer ring 51 of the bearing 26 and the support member 45
That is, the action of the retaining ring 53 prevents the outer ring 51 and thus the bearing 26 from being 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 (leftward in FIG. 2) of the heating roller 5 with respect to the support member 45, the displacement control member 139 is provided between the inner race 52 and the outer race 51 in the axial direction. 2 (right side in FIG. 2), a spring 127 is interposed almost exactly between the support member 45 and the displacement limiting member 139.

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 right side in FIG. 3 (right side in FIG. 10) 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 engagement piece 85 has an adjustment 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.

End 9 of heat source 4 inserted into 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 supporting shaft end 17 of fixing roller 3 has outer ring 104, inner ring 105, and rolling element 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.

In 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, and 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. 9) 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 shown in FIG.
Bring to 6. 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 from the side plate 15 to the mounting bolts 1.
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.

FIGS. 1, 2, 6, 7, 8, and 9
The belt meandering preventing means 63 will be described with reference to FIG. 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 detection member 120 has a belt contact portion 123 having a contact surface 122 whose outer diameter increases as it goes outward in the axial direction of the heating roller 5 (to the left in FIGS. 1, 8, and 9). Thus, the belt contact portion 123
Are formed in a truncated cone shape. The outer diameter of the end 124 on the small diameter side of the contact surface 122 of the belt contact portion 123 is
Is equal to the outer diameter of the belt contact portion 121 of FIG. The shaft end 24 is
Belt guide 1 around which belt 6 of heating roller 5 is wound
It has an outer diameter smaller than 21. 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-mentioned 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 direction in FIGS. 6 and 7. The displacement direction in which the guide slot 50 extends is a direction perpendicular to the up-down direction of the support member 45 in FIG. 1 and the left-right direction in FIGS. 6 and 7.

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 detecting spring 127 substantially surrounds the lower half of the bearing 26 in a U-shape. The two upper ends 128 and 129 of the meandering detection spring 127 are supported by the support member 45.
Are locked by the pins 130 and 131. The bearing 26 in the guide slot 50 and thus the shaft end 2 of the heating roller 5
4 is given a spring force in one direction going upward in FIG. 1 and upward in FIGS. 6 and 7.

When the outer ring 51 of the bearing 26 is in contact with the upper end 143 (see FIG. 7) of the elongated hole 50 due to the spring force of the spring 127, the belt 6 moves in the width direction of the belt 6 and, therefore, heats. 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 and contract, and its one end 133 is connected to the meandering detection 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. Thus, the cable 132 is connected to the cable detecting member 120.
Are in the same rotation direction as the heating roller 5,
When the cable 132 is angularly displaced (see FIG. 7), the cable 132 wraps around the cable guide portion 125, and thereby the heating roller 5
The shaft end 24 of FIG. 6 is opposed to the spring force in one direction above FIG. 6 and FIG. 7 by the meandering detection spring 127, and the shaft end 24 is in the other direction below FIG. 6 and FIG. To be displaced.

When the belt 6 meanders and rides on 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 meandering amount in the belt width direction. I do. 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 to the side plate 14 side is generated in the belt 6, and until the meandering component to the initial side plate 15 side cancels out.
The shaft end 24 is displaced downward along the guide slot 50.

As described above, the belt 6 meanders and rides on and comes into contact with the belt contact portion 123, so that the belt 6
Frictional force acts between the shaft and the contact surface 122, and thus the meandering detection member 120 is rotated with respect to the shaft end 24 as described above. By this rotation, as described above, the cable 132
Is wound around the cable guide portion 125. This cable 1
32 and the spring force of the meandering detection spring 127 are balanced, the amount of downward displacement of the shaft end 24 in FIGS. 6 and 7 is regulated, and thus the end of the belt 6 is located at a certain fixed position. 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
4, the outer ring 78 of 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 another embodiment, the axis of the heating roller 5 is 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. It is acceptable to do so.
6 and 7 of the shaft end 24 as described above.
Can be displaced to prevent the belt from meandering downward.

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, a disc-shaped displacement limiting member 139 is interposed between the retaining ring 138 and the bearing 26. The displacement limiting member 139 has an outer diameter larger than the outer ring 51 of the bearing 26, and has a slightly larger outer diameter than the curved portion of the meandering detection spring 127 wound in a U-shape. This prevents the meandering detection spring 127 from being displaced to the right in FIGS. 1 and 2 from the outer peripheral surface of the outer ring 51 and coming off. Further, this displacement limiting member 139 is
Since the outer diameter is larger than 26, the rope 132 is prevented from coming into contact with the bearing 26 and the meandering detection spring 127, and there is no possibility of being entangled. 1 (left of FIGS. 1 and 2). In this way, the meandering preventing operation of the belt 6 is reliably achieved.

[0079] A cable guide portion 125 formed integrally with the meandering detection member 120, a meandering detection spring 127, and a cable 1
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 contact surface 122 of the belt contact portion 123 of the meandering detection member 120 may have a uniform radius in the axial direction, and may further increase the coefficient of friction of the contact surface 122.

In the above embodiment, the meandering detecting member 12
The belt guide portion 123 of 0 is formed in the shape of a hollow truncated cone as described above, and the contact surface 122 forms an angle θ1 with the axis of the heating roller in a plane including the axis (see FIG. 2).
May be, for example, 0.75 to 2.0 degrees, but in other embodiments of the invention, the angle θ1 is substantially vertical, ie, 90 degrees or less than 90 degrees and approximately 90 degrees.
May be selected in the range of 70-90 degrees, or may be selected in the range of 85-90 degrees;
It may be 9 degrees. Experiments conducted by the present inventor have confirmed that by setting the angle θ1 substantially perpendicularly, the meandering amount of the belt 6 can be reduced and the life of the belt 6 can be extended.

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.

FIG. 12 is a partial sectional view of another embodiment of the present invention. This embodiment is described in FIGS.
Similar to the first embodiment, corresponding parts are denoted by the same reference numerals. Although the belt meandering preventing means 63 is provided on the side plate 15 side in the above-described embodiment, in another embodiment of the present invention, the belt meandering preventing means 63a is provided as shown in FIG.
Is provided on the side plate 14 side. 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, 12 of the meandering detection spring 127
9 is connected to the support member 73. One end of the cable 132 is connected to the meandering detection member 120 as described above, and
One end 135 is connected to the support member 73. Thus, in the embodiment of FIG. 12, the belt meandering prevention device 63
It 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 is connected to the retaining rings 80, 81, and 138.
It can be easily replaced by removing it.

In still another embodiment of the present invention, the shaft meandering means 63 described above with reference to FIGS. 1 to 9 is provided at the shaft end 24 of the heating roller 5, and another shaft end is provided. The part 23 is provided with the belt meandering preventing means 63a described with reference to FIG.
23 may be provided with belt meandering preventing means 63 and 63a, respectively.

The present invention is capable of the following embodiments.

(1) An endless belt is wound between a plurality of transport rollers, and is placed between a belt heated by a heat source and a pressure roller which comes into contact with the belt by a spring force.
In a belt fixing device which conveys a recording paper having a toner image therebetween and rotatably supports a conveying roller and a pressure roller on both side plates of a fixing device main body via bearings, one of the side plates 14 Has an insertion / removal hole 66 for inserting and removing a belt and each roller, and a detachable lid 71 is provided on an outer surface of the one side plate, and a bearing for supporting a transport roller is detachable on this lid. A belt fixing device, wherein the fixing device is provided in a belt fixing device.

According to the above configuration, an insertion hole 66 is formed in at least one of the side plates 14 of the fixing device main body 2, and a cover 71 is provided on the outer surface of the side plate 14 so as to be removable. By removing 71, belt 6 and each roller are inserted or removed from insertion hole 66, and thus belt 6 and each roller can be easily replaced. In this configuration, it is not necessary to disassemble and reassemble a large number of components constituting the belt fixing device 1 in order to replace the belt and each roller, and the workability is good.

Since only the belt 6 or the roller can be replaced and other components can be used as they are, there is no waste in discarding components whose life has not expired. Further, when replacing the belt 6 and the rollers, it is not necessary to disassemble many components as described above, and there is no possibility that the fixing performance is deteriorated.
Also, there is no problem that a high-precision mounting operation is required for replacing the rollers.

According to the above configuration, the belt 6 and the respective rollers can be inserted into and removed from the insertion hole 66 and taken out of the fixing device main body and replaced, so that maintenance workability is good. The configuration for such replacement of the belt and the rollers is relatively simple, and the configuration can be simplified. Further, only the belt or the roller can be replaced, so that there is no waste in removing and discarding other components whose life has not expired together with the belt and the roller. Further, by removing and replacing such belts and rollers, the positional accuracy after assembling can be maintained with high accuracy, which also improves the workability of maintenance. In this way, the replacement of the belt and the rollers requires only as few disassembly as possible, and the workability is good.

(2) A belt fixing device characterized in that the insertion / removal hole has a shape larger than the cross-sectional outer shape of the belt in a state of being stretched around the transport roller.

According to the above configuration, the belt 6 can be taken out and inserted from the side while the belt 6 is kept almost stretched for fixing, and the workability is good. .

According to the above-described configuration, the belt can be removed from the insertion / removal hole while keeping a state of being stretched around the transport roller, and a new belt can be inserted and assembled. As a result, an undesired force does not act on the belt, the belt does not come into contact with obstacles during work, and is not damaged or broken, and the workability is good.

(3) The inner rings 79 and 105 of the bearings 25 and 19 into which the shaft ends of the conveying rollers are inserted are located outside the conveying rollers in the axial direction of the conveying rollers, and the retaining rings 81 and 105 are attached to the shaft ends.
107. A belt fixing device which is detachably attached by 107.

According to the above configuration, the retaining rings 81, 107
From the shaft ends 23, 17 of the conveying rollers 5, 3 to the inner races 7 of the bearings 25, 19 supporting the shaft ends 23, 17.
9, 105 and thus the bearings 25, 19 can be removed. Thus, the disassembling and assembling work for replacing the belt 6 can be easily performed by the work from the outside of the fixing device main body 2.

According to the above configuration, the retaining rings 81, 107
Alternatively, by removing the E-ring, the shaft ends 23 and 17 of the transport roller and the bearings 25 and 19 can be detached and removed, so that disassembly is easy and assembly is easy.

(4) A belt fixing device characterized in that the transport roller includes a fixing roller 3 and a hollow heating roller 5 into which a heat source 4 is inserted.

According to the above configuration, one of the plurality of transport rollers is the fixing roller 3 and the other is the heating roller 5. A pressure roller 7 is pressed against the fixing roller 3 via a belt 6. The pressure roller 7 is a fixing roller 3
And the heating roller 5 may be configured to be pressed against the belt. The belt 6 is composed of the fixing roller 3 and the heating roller 5
In the configuration in which the belt 6 is stretched by only the configuration, the configuration is downsized, the cost is reduced, the heat loss is further reduced, and the contact angle in the circumferential direction of the heating roller 5 with which the belt 6 contacts the heating roller 5 is reduced. Roller 5
The heat conduction from the belt to the belt 6 can be performed favorably, whereby the heating time can be shortened and the energy saving effect can be improved.

According to the above-described structure, the belt is stretched between the fixing roller 3 and the heating roller 5 without using a tension roller or the like, so that heat loss is reduced and the belt comes into contact with the heating roller. By increasing the contact angle in the circumferential direction of the heating roller, heat can be satisfactorily conducted from the heating roller to the belt, whereby the heating time can be shortened and the energy saving effect can be improved.

(5) The lid 71 is detachably attached to the one side plate and supports the auxiliary plate 7 for supporting the bearing of the fixing roller.
And one support member 73 provided on the auxiliary plate so as to be movable in the radial direction of the fixing roller and supporting one end of a heat source and one bearing for supporting the heating roller. One end 84 of the belt tension applying spring 82 is connected to the auxiliary plate, and the other end 83 is connected to the one support member, thereby applying a spring force radially outward of the fixing roller to fix the fixing roller. On the other side plate 15 of the apparatus main body, the other support member 4 is movably movable in the radial direction of the fixing roller.
5, the other supporting member detachably supports the other bearing for supporting the heating roller and the other end of the heat source, and one end of the other belt tension applying spring 55 is connected to the other of the other bearing. A belt fixing device, wherein the belt fixing device is connected to a side plate, and the other end is connected to the other support member, thereby applying a spring force to the fixing roller in a radially outward direction.

According to the above configuration, the lid 71 for closing the insertion / removal hole 66 of the one side plate 14 of the fixing device main body 2 is
The fixing roller 3 is supported by the auxiliary plate 72 and the other side plate 15 of the fixing device main body 2. The shaft end 17 of the fixing roller 3 can be removed from the bearing 19 attached to the auxiliary plate 72. Further, the one support member 73 and the other support member 45 provided on the other side plate 15 of the fixing device main body 2 are given spring force by two belt tension applying springs 82 and 55,
Thereby, tension is applied to the belt 6. The shaft end 23 of the heating roller 5 can be removed from the bearing 25 attached to the one support member 73. Auxiliary plate 72
Is the fixing device main body 2 together with the one support member 73.
Is detachable from the one side plate 14. Therefore, the shaft ends 17, 25 of the fixing roller 3 and the heating roller 5 can be removed from the auxiliary plate 72 and the one support member 73, and thus the insertion / removal hole 66 can be opened.

When the belt 6 is replaced in this manner, the belt 6 can be detached from the insertion / removal hole 66 by disassembling as few components as possible for constituting the belt fixing device 1, and a new belt 6 can be removed. It can be inserted from the insertion hole 66. According to such a configuration, the maintenance accuracy of the belt fixing device 1 is not reduced, and the maintenance work is easy.

According to the above-described configuration, the fixing roller is connected to the cover 7.
1 is supported by an auxiliary plate 72, and a heating roller is supported by one supporting member 73 forming a lid. The other supporting member supports the one supporting member and the other shaft end 24 of the heating roller. Since the spring force is applied to the member 45 by the two belt tension applying springs 82 and 55, tension can be applied to the belt to generate the tension, and at least one of the belt tension applying springs can be applied. By removing one of the ends and releasing its spring force, the belt can be removed and replaced easily.

(6) One bearing that removably supports one shaft end of the pressure roller and one shaft end thereof is formed on the one side plate and extends elongated in the radial direction of the fixing roller. Is provided in the long hole 42 so as to be displaceable along the one long hole and to be detachable from the one side plate, and the one long hole is provided outside the one shaft end of the pressure roller. The pressure roller can be inserted into and removed from the insertion hole through a connection hole 68 having a width larger than the diameter, and the pressure roller can be inserted into and removed from the insertion hole, and the other shaft end of the pressure roller is connected to the other shaft. The other bearing that removably supports the end and the other side plate is formed on the other side plate and extends in the other elongated hole 43 elongated in the radial direction of the fixing roller, so as to be displaceable along the other elongated hole, and A bell provided on the other side plate 15 so as to be detachable. The fixing device.

According to the above configuration, the pressure roller 7 is pressed against the fixing roller 3 via the belt, or the pressure roller 7 is a belt 6 wound around the fixing roller 3 and the heating roller 5. Is pressed against. One bearing 33 is removed from one shaft end 31 of the heating roller 7 shown in FIG. 9, and the one bearing 33 is removed from one side plate 14 of the fixing device main body 2. Further, FIG.
And the other shaft end 32 shown in FIG.
Remove from 4. The other bearing 34 is removed from the other side plate 15 of the fixing device main body 2. In this state, the pressure roller 7
Of one shaft end 33 from one long hole 42 to the connection hole 68
Via the heating roller 3 which has been already removed. At the same time, the other shaft end 32 of the pressure roller 7 is displaced in the other long hole 43 to bring it to the position where the previously removed fixing roller 3 was arranged. Thus, the pressure roller 7 can be moved in the axial direction and taken out of the fixing device main body 2 through the insertion / removal hole 66. In this manner, removal and assembly of the pressure roller 7 can be easily performed.

According to the above configuration, not only the fixing roller and the heating roller, but also the pressure roller 7 can be displaced through the connection hole 68 and removed from the insertion / removal hole 66. In this way, all the rollers can be easily removed.

(7) A meandering detection member 1 having a belt contact portion 123 which is rotatably supported on at least one shaft end of the heating roller and which is rotatable with respect to the shaft end, and which comes into contact with the belt.
20; roller support means 25, 73, 82 for supporting the shaft end supporting the meandering detection member in a predetermined displacement direction orthogonal to the axis of the heating roller; Roller shaft end displacement means 125, 127, 132 for displacing the shaft end supporting the meandering detection member of the heating roller in the predetermined displacement direction when the belt comes into contact with the detection member and torque is applied. And a meandering detection member, a roller supporting means, and a roller shaft end displacement means are provided inside the one side plate and closer to the one side plate.

According to the above configuration, a meandering detecting member 120 for preventing the belt 6 from meandering as shown in FIG.
And the roller support means 25, 73, 82 and the roller shaft end displacement means 125, 127, 132
Are provided near the one side plate 14 in which the insertion / removal hole 66 is formed, whereby the meandering detection member 120 and the roller support Maintenance work such as replacement, removal, and assembly of the means and the roller shaft end displacement means can be easily performed.

According to the above configuration, the meandering detecting member 120 for preventing the belt from meandering and the roller supporting means 140 are provided.
And the roller shaft end displacement means 141 are connected to the fixing device main body 1.
By disposing it near one of the side plates 14, inspection, removal, assembly, and replacement of these components can be performed with as little disassembly as possible, thus facilitating maintenance of the mechanism for preventing meandering. become. This is particularly important when it is necessary to periodically replace a meandering detection member used in an environment at a high temperature of 160 to 200 ° C., for example.

[0109]

According to the first aspect of the present invention, instead of using a tension roller having a mechanism for preventing the belt from meandering as described in relation to the prior art, the belt is meandered in relation to the heating roller. A prevention means is provided, whereby the structure can be reduced in size, and 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, it is possible to increase the circumferential contact angle of the heating roller with which the belt is wound around and comes into contact with the heating roller. 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 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 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 second aspect of the present invention, when the belt is meanderingly displaced and comes into contact with the belt contact portion of the meandering detecting member, and thereby the meandering detecting member is rotated, the rotational movement of the meandering detecting member is transmitted to the roller shaft. The motion is converted into a linear motion by the end displacement means, and the shaft end of the heating roller is displaced in the predetermined displacement direction, whereby a meandering displacement is generated in the belt in the opposite direction, and the initial meandering can be eliminated. According to this configuration, the amount of displacement of the shaft end of the heating roller according to the initial meandering is automatically given and the meandering of the belt is eliminated, so that the belt runs stably and the fixing operation of the belt is stabilized. Can be done. Thus, a toner image can be accurately formed on recording paper by belt fixing.

According to the third aspect of the present invention, the fixing roller is provided on the fixing device main body with its rotation axis fixed, and the pressing roller is moved toward the fixing roller by a relatively large pressing spring. The heating roller can be pressed, and the heating roller is provided with a spring force by a belt tension applying spring to apply tension to the belt, and thus the recording paper is sandwiched between the belt and the pressure roller, thereby improving the fixing quality. be able to. Further, since the position of the fixing roller is fixed as described above, the fixing roller can be driven to rotate stably.

According to the fourth aspect of the present invention, the belt is wound around a total of two rollers, such as a heating roller and a fixing roller, so that the configuration can be reduced in size and the cost can be reduced. It is planned. Further, the heat loss is reduced, and the contact angle of the belt with the heating roller is increased, so that the heat conduction can be performed satisfactorily. Can be shortened, and the energy saving effect can be improved.

According to the fifth aspect of the present invention, the meandering detecting member is supported by the shaft end of the heating roller, so that the configuration is simplified and the maintenance is simplified.

According to the sixth aspect of the present invention, in order to support the heating roller on the supporting member and apply tension to the belt by the belt tension applying spring to prevent the belt from meandering,
A shaft end supporting the meandering detection member of the heating roller is provided on the support member so as to be displaceable in a direction orthogonal to the direction of movement of the support member, which is the predetermined displacement direction, so that meandering of the belt can be prevented. By the function of the support member, tension can be applied to the belt, and the shaft end of the heating roller can be displaced to prevent meandering of the belt. In this way, the heating roller is supported by the pair of support members, and the belt tension is applied by the belt tension applying springs 55 and 82 to apply tension to the belt, thus preventing the support member from meandering. Since the configuration for this is integrated, the configuration can be simplified and maintenance can be facilitated.

According to the present invention, at least one of the belt tension applying springs provided for each of the pair of support members or the spring force of both of them is adjusted by means such as the bolt 89. A belt tension that can further suppress belt meandering can be provided.

According to the eighth aspect of the present invention, the roller shaft end displacing means includes the meandering detecting spring 127 and the cable 132, so that the configuration can be simplified.

[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 an exploded perspective view near the side plate 15. FIG.

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

FIG. 9 is a simplified perspective view showing a heating roller 5 and a part of a configuration related thereto.

FIG. 10 is a right side view of the belt fixing device 1.

FIG. 11 is an exploded perspective view of the side plate 14 of the fixing device main body 2 and its vicinity.

FIG. 12 is a partial cross-sectional view of another embodiment of the present invention.

[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 elongated hole 45, 73 Support member 51, 68, 100, 101, 104 Outer ring 52, 69, 102, 105 Inner ring 55, 82 Belt tension applying 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

Continued on the front page (72) Inventor Takayuki Yoshida 3-2-15-1 Meiwadori, Hyogo-ku, Kobe-shi, Hyogo Inside Bando Chemical Co., Ltd. (72) Inventor Shigeo Kurodaka 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H033 BA02 BA11 CA01 CA35 3F023 AA05 BA02 BB05 BC01 CA02 GA03 3F033 GA02 GB04 GE06 LA05 3F104 AA00 CA11 CA35

Claims (8)

[Claims] An endless belt is wound around a plurality of rollers including a heating roller provided with a heat source, and a recording sheet having a toner image is nipped and conveyed between the belt and a pressure roller; A belt fixing device, wherein a meandering preventing means for preventing the belt from meandering is provided on the heating roller. 2. A meandering detecting member 120 having at least one shaft end of a heating roller rotatably supported by at least one shaft end thereof and a belt contact portion 123 contacting a belt; Roller support means 140 for supporting the shaft end supporting the meandering detection member so as to be displaceable in a predetermined displacement direction orthogonal to the axis of the heating roller, and connected to the meandering detection member, and connected to the belt contact portion of the meandering detection member. Roller shaft end displacement means 14 for displacing the shaft end supporting the meandering detecting member of the heating roller in the predetermined displacement direction when torque is applied by contact of the belt.
2. The belt fixing device according to claim 1, further comprising: 3. The heating roller is disposed upstream of the remaining rollers other than the heating roller in the conveyance direction of the recording paper in the conveyance direction of the recording paper, and one of the remaining rollers is: The fixing roller is provided on the fixing device main body so as to be rotatable with the position of the rotation axis fixed, and is rotationally driven by driving means. The pressure roller is provided on the fixing device main body with a radius of the fixing roller. The pressure roller is provided with a spring force toward the fixing roller via a belt by a pressure spring, and at least one of the shaft ends supporting the meandering detection member of the heating roller is provided. The fixing roller is provided on the fixing device main body so as to be displaceable in the predetermined displacement direction, which is a circumferential direction about the rotation axis of the fixing roller, and to be displaceable in the radial direction of the fixing roller. 3. The belt fixing device according to claim 2, wherein a spring force in a direction away from the fixing roller in a radial direction of the fixing roller is applied to both ends of the shaft by a belt tension applying spring. 4. The belt fixing device according to claim 1, wherein the belt is wound around only a heating roller and another roller among the rollers. 5. The shaft ends 24 and 23 supporting the heating roller meandering detection member have an outer diameter smaller than the belt guide portion 121 around which the belt of the heating roller is wound. The belt fixing device according to any one of claims 2 to 4, wherein the detection member is inserted coaxially. 6. The roller supporting means has a pair of supporting members 45 and 73 provided on the fixing device main body so as to rotatably support both ends of the heating roller and to be movable in a radial direction of the fixing roller. The predetermined displacement direction of the shaft end supporting the meandering detection member of the heating roller is a direction orthogonal to the moving direction of the support member, and each support member is provided with the belt tension applying springs 55 and 82. The belt fixing device according to any one of claims 3 to 5, wherein a spring force is applied outward of the fixing roller in the radial direction. 7. The belt fixing device according to claim 3, further comprising a means for adjusting a spring force of at least one of the belt tension applying springs. 8. A roller shaft end displacing means is provided on a cable guide portion 125 formed outside the belt contact portion 123 of the meandering detection member in the axial direction, and on the support member 45, and detects the meandering of the heating roller. A meandering detection spring 127 for applying a meandering detection spring force to the shaft end 24 supporting the member in one direction orthogonal to the moving direction of the support member; one end fixed to the cable guide portion; The end is fixed to the support member, and when the belt comes into contact with the belt guide and a torque is applied, the rope guide is wound in the winding direction against the meandering detection spring force. Wherein the shaft end includes a cable 132 which is displaced in the other direction perpendicular to the direction of movement of the support member and opposite to the one direction. 8. The belt fixing device according to 6 or 7.