JP3734121B2 - Belt drive device and belt fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a belt driving device for rotating and conveying a belt and a belt fixing device using the belt driving device.
[0002]
[Prior art]
Conventionally, the following methods are generally used as belt slip prevention methods in belt drive devices.
1. A belt-side regulating member affixing method in which a belt-side regulating member is affixed to the inner or outer peripheral surface of the belt side end.
2. Belt detent system with belt detent at the roller end.
3. A belt shaft end displacement system that prevents the belt from shifting by displacing the roller shaft end in the direction in which the belt has moved due to the belt shifting action.
4). As a technique close to the present invention, for example, as described in Japanese Utility Model Laid-Open No. 5-14046, a belt-side end provided with a reinforcing member, or as described in Japanese Patent Laid-Open No. 4-121337, There is a belt meandering prevention method that uses torque generated by belt rotation. In the latter belt meandering prevention method, when the belt side end portion rides on the meandering detection member, the inner peripheral surface of the belt is rubbed against the meandering detection member to generate a rotational torque of the meandering detection member. At this time, the thread wound around the main body side and the meandering detection member is wound, and the driven roller is displaced in a direction to stop meandering. That is, the belt meandering prevention system is characterized in that the rotational motion of the meandering detection member is converted into a predetermined linear motion by the yarn.
[0003]
[Problems to be solved by the invention]
However, the above 1. However, when a large deviation force is applied to the belt, the belt deviation restriction member peels off or the belt gets over the belt deviation restriction member.
[0004]
2. In the belt detent method, when a large deviating force acts on the belt, there is a problem that the belt side end portion is damaged due to the buckling phenomenon of the belt.
[0005]
3. above. In this belt shaft end portion displacement method, electromagnetic opening / closing means such as a clutch and a solenoid are used as the roller shaft end portion displacement means, but there is a problem that causes an increase in cost.
[0006]
4. above. In the belt meandering prevention system, the friction coefficient changes due to changes in the contact surface state due to frictional wear between the belt and the meandering detection member, or foreign matter adhering to the belt inner peripheral surface and the meandering detection member. There is a problem that the amount of meandering is not stable.
[0007]
Accordingly, it is an object of the present invention to solve the above-mentioned problems, to prevent the belt from shifting, and to prevent a short belt life due to a crack breakage of the belt side end caused by contact between the belt side end and the belt guide member. It is what.
[0008]
The purpose of each claim is as follows.
[0009]
The object of the invention described in claims 1 and 2 is to reduce the belt shifting force by a belt driving device having a belt shifting preventing means comprising a belt guide member, a belt guide urging member, a supporting means and a converting means. It is intended to prevent deviation and to prevent a short belt life due to crack breakage of the belt side end caused by contact between the belt side end and the belt guide member.
[0010]
In addition to the objects of the first and second aspects of the present invention, the object of the present invention is to prevent wear due to rubbing of the belt guide member or the conversion means and to obtain reliability over time.
[0011]
The object of the invention of claim 7 is to ensure that the effect of preventing belt slippage is exerted by reducing the frictional resistance at the end of the driven shaft smoothly when the driven shaft is displaced to prevent belt slippage. It is in.
[0012]
In addition to the object of the invention described in claim 7, the object of the invention described in claim 8 is the shaft end portion which does not cause a problem that the driven shaft performs an unstable operation during rotation and inhibits the belt slippage preventing action. The support member is used.
[0013]
The object of the invention described in claim 9 is to apply the belt driving device having the belt slip prevention means according to any one of claims 1 to 8 to the belt fixing device, to enhance the belt damage prevention effect, and to It is to realize a belt fixing device having a characteristic.
[0014]
The object of the invention described in claims 10 and 11 is to prevent wrinkles and jams due to skew of the recording paper in addition to the object of the invention described in claim 9.
[0015]
[Means for Solving the Problems]
In order to achieve the above-described object, the invention described in claim 1 is characterized in that the endless belt stretched between at least the drive shaft and the driven shaft, and the endless provided at at least one of the driven shaft end portions. A belt guide member that moves in the axial direction in response to a shift of the belt in the axial direction of the driven shaft and a belt guide member that is provided on at least one of the driven shaft end portions is biased in the axial center direction. A belt guide urging member; a support means for supporting the driven shaft end so as to be displaceable in a direction perpendicular to the axial direction; and a displacement of the belt guide member in the axial direction in contact with the belt guide member Conversion means for converting the displacement into a displacement in a predetermined direction perpendicular to the axial direction.
[0016]
According to a second aspect of the present invention, in the belt driving device according to the first aspect, the conversion means has an inclined surface that contacts the belt guide member and guides the driven shaft so as to be displaceable in the predetermined direction. Features.
[0017]
According to a third aspect of the present invention, in the belt driving device according to the second aspect, a rotating member that rotates while contacting the belt guide member is provided on the inclined surface of the converting means.
[0018]
According to a fourth aspect of the present invention, in the belt driving device according to the third aspect, the belt guide member includes a rotating member that contacts the inclined surface in a stationary state.
[0019]
According to a fifth aspect of the present invention, in the belt driving device according to the first aspect, the belt guide member has a rotating member that comes into contact with the converting means in a stationary state, and the converting means contacts the rotating member. However, the rotation guide member is configured to smoothly convert the displacement of the driven shaft end portion in the predetermined direction.
[0020]
According to a sixth aspect of the present invention, in the belt driving device according to the first aspect, the conversion means smoothly converts the displacement of the driven shaft end portion in the predetermined direction while contacting the belt guide member. It is characterized by comprising.
[0021]
A seventh aspect of the present invention is the belt driving apparatus according to any one of the first to sixth aspects, wherein the support means includes a shaft end supporting member that supports the driven shaft end, and the endless belt. A belt urging member that urges to a predetermined position in a tensioning direction, and an insertion support member having a long hole shape for inserting and supporting the shaft end portion support member, A long hole shape extends in a direction in which the endless belt is stretched and in a direction in which the shaft end support member is displaced in the predetermined direction.
[0022]
According to an eighth aspect of the present invention, in the belt driving device according to the seventh aspect, a rolling bearing is used as the shaft end portion supporting member.
[0023]
According to a ninth aspect of the present invention, in the belt driving device according to any one of the first to eighth aspects, the endless belt is a fixing belt for fixing unfixed toner on the recording paper, and the driven shaft is disposed therein. And a heating member for heating the fixing belt, the driving shaft being a fixing member, and a pressing member that presses against the fixing member via the fixing belt to form a fixing nip portion. This is a belt fixing device.
[0024]
A tenth aspect of the present invention is the belt fixing apparatus according to the ninth aspect, wherein the fixing member and the pressure member are parallel to the inner peripheral surface side of the fixing belt between the heating member and the pressure member. In addition, a guide member that contacts the inner peripheral surface of the fixing belt is provided.
[0025]
The invention according to claim 11 is the belt fixing device according to claim 9 or 10, wherein the fixing belt conveying speed of the fixing belt and the conveying device conveying speed of the conveying device for conveying the recording paper to the fixing nip portion are: The fixing belt conveyance speed ≦ the conveyance apparatus conveyance speed is satisfied.
[0026]
According to a twelfth aspect of the present invention, in the belt drive device according to any one of the first to eighth aspects, the driven shaft and the drive shaft are both rollers.
[0027]
According to a thirteenth aspect of the present invention, in the belt fixing device according to any one of the ninth to eleventh aspects, the driven shaft and the drive shaft are both rollers.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention including examples will be described with reference to the drawings (hereinafter simply referred to as “embodiments”). In each of the embodiments and the like, components having the same functions and shapes are denoted by the same reference numerals, and description thereof is omitted as much as possible. In the figure, components that are configured as a pair and do not need to be specifically distinguished and described are described by appropriately describing one of them in order to simplify the description.
[0029]
First, the configuration of a belt driving device to which the present invention is applied will be described with reference to FIGS.
FIG. 4 shows a belt driving device to which the present invention is applied. This belt driving device includes a driving roller 1 as at least one driving shaft, a driven roller 2 as at least one driven shaft, and a driving roller. 1 and an endless belt 3 (hereinafter simply referred to as “belt 3”) wound around the driven roller 2 and stretched between them. The drive roller 1 is integrally formed with the shaft 1a and the driven roller 2 is integrally formed with the shaft 2a. The drive roller 1 and the driven roller 2 are rotated clockwise through the shafts 1a and 2a, respectively. It is supported freely. The belt 3 is a flat belt having a relatively long belt width and is in a state of being rotated and conveyed in a belt rotation direction 3B which is a clockwise direction in FIG. As shown in FIG. 7, the belt 3 has a spring 4 (tensile) stretched between a support portion of the shaft 2a of the driven roller 2 and a stationary member (not shown) provided on the belt driving device main body side. A predetermined tension P2 is applied by a spring).
[0030]
FIG. 5 is a plan view of the belt driving device shown in FIG. 4 as viewed from the top A, and shows a state in which the left shaft end portion of the driven roller 2 is displaced in the non-parallel left direction 2B1 in FIG. The driven roller 2 is in a non-parallel positional relationship with respect to the drive roller 1. In FIG. 7, the state where the left shaft end portion of the driven roller 2 is displaced in the non-parallel right direction 2B2 is shown together with the non-parallel left direction 2B1. The non-parallel left direction 2B1 and the non-parallel right direction 2B2 are collectively referred to as a non-parallel direction 2B.
[0031]
FIG. 6 is a front view of the belt driving device shown in FIG. 4 as viewed from the side B, and shows a state in which the right shaft end portion of the driven roller 2 is displaced in the torsional downward direction 2A1, which is the downward displacement direction. The driven roller 2 is twisted with respect to the drive roller 1. In FIG. 7, the state where the right shaft end portion of the driven roller 2 is displaced in the twisting upward direction 2A2 that is the upward displacement direction is shown together with the twisting downward direction 2A1. The twisting downward direction 2A1 and the twisting upward direction 2A2 are collectively referred to as the twisting direction 2A.
[0032]
In the case of the non-parallel positional relationship as shown in FIG. 5, the belt shift phenomenon causes the belt to move in the non-parallel left direction 2 </ b> B <b> 1, which is the direction in which the driven roller 2 approaches the drive roller 1, as indicated by the belt shift direction 3 </ b> A. 3 approaches. At this time, of the driving force F transmitted from the driving roller 1 to the belt 3, the component force f in the axial direction of the driven roller 2 is the frictional force f between the inner peripheral surface of the belt 3 and the axial direction of the driven roller 2. (= Μ · N: μ: friction coefficient between the inner peripheral surface of the belt 3 and the outer peripheral surface of the driven roller 2, N: drag force acting perpendicularly to the shaft 2a of the driven roller 2).
[0033]
When the belt 3 is rotationally conveyed in the belt rotation direction 3B in the twisted positional relationship as shown in FIG. 6, the right shaft of the driven roller 2 is explained as will be described in the first embodiment described later. When the end portion is displaced in the downward twisting downward direction 2A1 and twisting occurs, the belt 3 approaches the belt shifting direction 3A1, which is the direction opposite to the direction of displacement. This is considered to be because when the belt 3 is wound around the driven roller 2, the belt 3 is shifted in that direction by the amount of twist. In that case, the amount of deviation of the belt 3 occurs to such an extent that even if the driven roller 2 is slightly twisted with respect to the driving roller 1, the belt deviation is surely generated.
[0034]
On the other hand, in the non-parallel positional relationship as shown in FIG. 5, the friction coefficient μ is related to the frictional force between the inner peripheral surface of the belt 3 and the outer peripheral surface of the driven roller 2. In this case, if the contact state changes, the friction coefficient μ changes, and the belt shifting force tends to change between the initial time and time, which is unstable (the friction coefficient μ increases over time). In many cases, the belt shifting force will increase).
[0035]
FIG. 8 shows a belt when the shaft end portion of the driven roller 2 is displaced in the non-parallel direction 2B and the twist direction 2A by the same displacement amount (mm) in the configuration conditions of the belt driving device shown in FIGS. It is a confirmation result of the amount of deviation (mm). As is apparent from FIG. 8, the torsional component (twisting direction 2A) of the driven roller 2 with respect to the driving roller 1 is more dominant with respect to the belt displacement than the parallel component (non-parallel direction 2B). It turns out that there is, and this has been confirmed experimentally.
[0036]
From the above results, it is clear that when the driven roller 2 is displaced to prevent the belt from shifting, it is desirable to displace the component in the twisting direction 2 </ b> A with respect to the driving roller 1. Therefore, in the case of the embodiment described later, as a method of preventing the belt deviation, it is described that the shaft end portion of the driven roller 2 in the direction in which the belt deviation phenomenon occurs is displaced in the twisting downward direction 2A1 as the predetermined direction. Yes.
(Embodiment 1)
1 to 3 show a first embodiment of the present invention (hereinafter simply referred to as “Embodiment 1”).
The belt driving device according to the first embodiment is wound around at least one driving roller 1, at least one driven roller 2, and the driving roller 1 and the driven roller 2, as shown in FIGS. A belt 3 stretched between them, a belt guide member 5 that moves the belt 3 in the direction of the shaft 2a in accordance with the deviation of the driven roller 2 of the belt 3 in the direction of the shaft 2a, and a belt guide member 5 that is in the center of the shaft 2a A spring 8 (compression spring) as a belt guide urging member for urging in the direction, a support means 16 for supporting the shaft end portion of the driven roller 2 so as to be displaceable in a direction perpendicular to the direction of the shaft 2a, and a belt guide member And a conversion means 6 that contacts the belt 5 and converts the displacement of the belt guide member 5 in the direction of the shaft 2a into the displacement of the twisted downward direction 2A1 as a predetermined direction perpendicular to the direction of the shaft 2a. That.
[0037]
As shown in FIGS. 1 and 3, the belt guide member 5 has a ring shape, and is made of, for example, a plastic member. The belt guide member 5 is formed with a fitting portion 5b that is loosely fitted into the shaft 2a of the driven roller 2. On the left side surface of the belt guide member 5 in FIG. 1, an anti-rotation protrusion 5 a for rotating together with the driven roller 2 is formed to protrude. The anti-rotation protrusion 5a is movable in the direction of the shaft 2a by a guide hole 2b formed to open on the end surface of the driven roller 2. The spring 8 is wound around a shaft 2 a between the right side surface of the belt guide member 5 in FIG. 1 and the left side surface of a ball bearing 7 described later, and the direction in which the belt guide member 5 is always pressed against the end surface of the driven roller 2. That is, the belt 3 is biased in the direction opposite to the direction 3A1 in which the belt 3 moves.
[0038]
The converting means 6 is constituted by a guide member 6 (hereinafter referred to as “converting means 6”) having an inclined surface 6a that contacts the belt guide member 5 and twists the driven roller 2 so as to be displaceable in the downward direction 2A1. Yes. The conversion means 6 is made of, for example, metal, and is fixed to a side plate 10 disposed on the main body side of the belt driving device by fastening means such as screws.
[0039]
The support means 16 is a shaft end supporting member that supports the end of the shaft 2a of the driven roller 2, and a belt urging member that urges the belt 3 in a direction in which the belt 3 is stretched and to a predetermined position. And a side plate 10 as an insertion support member having a long hole shape 10a for inserting the shaft end portion support member. As shown in FIG. 2, the spring 4 is provided to urge a rolling bearing 7 (described later) disposed on both sides of the driven roller 2 in a direction in which the belt 3 is stretched in a direction of pulling obliquely upward. In FIG. 2, as a component force of the force F of the spring 4, a symbol F <b> 1 represents a force that urges the driven roller 2 to a predetermined position, and a symbol F <b> 2 represents a force that stretches the belt 3 in a predetermined direction. .
[0040]
As the shaft end support member, a ball bearing as the rolling bearing 7 is used. Both end portions of the shaft 2 a of the driven roller 2 are supported by the side plate 10 via the bearing support plate 9 by the rolling bearing 7. In the rolling bearing 7, the left side wall of the outer race protrudes to the outer periphery, and the elongated hole shape 10 a of the side plate 10 is formed in a groove formed between the bearing support plate 9 fitted to the right outer periphery of the outer race. Since the peripheral portion is loosely fitted, it is guided and supported so as to be displaceable in the torsional downward direction 2A1. Further, both ends of the shaft 2a of the driven roller 2 are prevented from coming off by stoppers 18 made of C-rings or E-rings fitted and fitted to the respective ends.
[0041]
As shown in FIG. 13, the long hole shape 10a is formed at a predetermined position of the side plate 10 by extending in the direction in which the belt 3 is stretched and in the direction in which the rolling bearing 7 is twisted and displaced downward 2A1. .
[0042]
Next, the operation will be described.
In FIG. 1, the belt guide member 5 is in a state of rotating together with the driven roller 2 by having the rotation preventing projection 5 a and the fitting portion 5 b. When the belt shift occurs and the belt 3 moves in the belt shift direction 3A1, the belt guide member 5 is also pushed by the side end of the belt 3 and moves in the belt shift direction 3A1 against the biasing force of the spring 8. To do. At this time, as shown in FIG. 3, the belt guide member 5 is displaced along the inclined surface 6a while the outer peripheral corner portion of the belt guide member 5 contacts and rubs against the inclined surface 6a of the converting means 6, and the driven roller 2 also has a shaft. In the first embodiment, a predetermined direction perpendicular to the 2a direction is displaced in a twisting downward direction 2A1 indicated by a broken line. At this time, a force is exerted on the belt 3 so as to approach the belt deviation reducing direction 3A2 indicated by a broken line which is the opposite direction to the belt rotation direction 3B, and as the displacement amount of the driven roller 2 decreases, the belt 3 The shifting force is also reduced, and the belt guide member 5 prevents the shifting of the belt 3 while reducing the force of the belt 3 trying to move in the belt shifting direction 3A1. Here, the side end portion of the belt 3 refers to a portion in the vicinity of the side edge including the side end and the side end surface of the belt 3.
[0043]
As described above, in the configuration of the first embodiment, the belt 3 is rotated while being guided by the belt guide member 5 in a state in which the force of the belt 3 in the belt shift direction 3A1 is reduced. In other words, a biasing force acts on the belt 3, the belt guide member 5 provided at the shaft end of the driven roller 2 is pushed by the belt 3, and the belt guide member 5 moves in the direction of the shaft 2 a of the driven roller 2. Then, the driven roller 2 is displaced in the twisting downward direction 2A1 that reduces the shifting force of the belt 3. That is, the present invention is a belt slip prevention technique characterized by converting the linear movement of the belt guide member 5 when a slip force is applied to the belt 3 into a predetermined linear motion that reduces the slip force of the belt 3. It can be said that there is.
[0044]
The basic configuration for preventing belt deviation in the first embodiment as described above, that is, the belt guide member 5, the spring 8 as the belt guide biasing member, the support means 16, and the conversion means 6 are collectively referred to as a belt deviation prevention means 19. And
[0045]
Therefore, according to the first embodiment, the belt drive device having the belt deviation prevention means 19 rotates with the side end portion of the belt 3 being guided by the belt guide member 5 while the belt deviation force is reduced. In addition to preventing the belt from shifting, even if the belt 3 rotates and transports for a long time, it prevents a short belt life due to a crack breakage of the side end 3a of the belt 3 caused by contact between the side end 3a of the belt 3 and the belt guide member 5. can do.
[0046]
In addition, since the oblong shape 10a is formed in the side plate 10, the driven roller 2 is twisted as a predetermined direction and displaced in the downward direction 2A1 in order to prevent the belt shift when the belt shift prevention function is activated. However, there is an advantage that the driven roller 2 is easily displaced by eliminating the frictional resistance in the rolling bearing 7 at that time.
[0047]
Further, when the belt 3 is rotating, a rotational torque acts on the driving roller 1 as a fulcrum, and a force for moving the driven roller 2 downward is generated. At this time, since the shaft end support member for supporting the shaft 2a of the driven roller 2 uses a rolling bearing 7 (ball bearing) having a very small rotational torque, the driven roller 1 is driven even if the rotational torque acts on the fulcrum. The force that the roller 2 moves downward is extremely small. Therefore, when the belt 3 is rotating, the driven roller 2 does not move unstablely against the urging force of the spring 4 by the force of the driven roller 2 moving downward.
[0048]
【Example】
A description will be given of the results of an experiment conducted using the belt driving apparatus having the belt deviation prevention means 19 of the first embodiment and actually rotating the driving roller 1 to continuously rotate and convey the belt 3. The specifications and experimental conditions of the components constituting the belt slip prevention means 19 are as follows.
[0049]
The belt 3 was made of a silicone rubber layer on a nickel base and had a thickness of 190 μm. The belt offset force was set to 400 g · f. Both shaft end portions (rolling bearings 7) of the driven roller 2 are lifted 30 degrees upward to the right in FIGS. 2 and 13 by a tension coil spring as a spring 4 set to a spring load of 1 kg · f on one side. . The inclination angle of the inclined surface 6a of the converting means 6 was set to 30 degrees upward in FIGS. 1 and 3, and the mounting load of the spring 8 was set to 100 g · f on one side. The shaft 2a of the driven roller 2 is made of aluminum, the belt guide member 5 is made of plastic, and the conversion means 6 is made of a sheet metal member.
[0050]
Under these conditions, a continuous test was conducted. As a result, it was confirmed that even if the operation was performed for 200 hours or more, the belt was not shifted and the side end portion of the belt 3 was not cracked. At this time, the moving amount of the belt guide member 5 in the direction of the shaft 2a was 1 mm.
[0051]
In addition, the belt 3 is not displaced when the belt 3 is moved and the driven roller 2 is displaced in the twisted downward direction 2A1 to reduce the displacement force of the belt 3. However, in the configuration of the first embodiment, the belt displacement force is Considering the reaction force due to the frictional force of the belt guide member 5 against the biased spring 8 and the inclined surface 6a of the converting means 6, the belt shifting force is not lost but the belt of the order of several tens g · f. It was found that it was alleviated by the leaning force.
[0052]
In the first embodiment, the case where a series of means constituting the belt deviation prevention means 19 for preventing belt deviation is provided on both sides of the driven roller 2 is not limited to this. The driven roller 2 may be displaced so as to approach one side of the driven roller 2, and the belt shift prevention means 19 may be disposed only on one side of the driven roller 2.
[0053]
FIG. 9 shows a modification of the first embodiment.
[0054]
This modification differs only in having a belt guide member 5 ′ as shown in FIG. 9 instead of the belt guide member 5 of the first embodiment. In order to reduce the contact area with the outer peripheral surface of the shaft 2a of the driven roller 2 with respect to the belt guide member 5, the belt guide member 5 'is in contact with the outer peripheral surface of the shaft 2a. The recess 5c is formed by slightly curving the peripheral surface.
(Embodiment 2)
FIG. 10 shows a second embodiment of the present invention (hereinafter simply referred to as “second embodiment”). The second embodiment is different from the first embodiment only in that the inclined surface 6 a of the converting means 6 is provided with a roller 11 as a rotating member that rotates while contacting the belt guide member 5. The roller 11 is formed integrally with the roller shaft 11a, and is rotatably supported by the conversion means 6 via the roller shaft 11a.
[0055]
In the first embodiment, the belt guide member 5 is in a state of rotating with the driven roller 2, and the belt guide member 5 contacts the inclined surface 6a of the converting means 6 and rotates and rubs against the inclined surface 6a. Accordingly, either one of the belt guide member 5 and the conversion means 6 is worn, and durability and reliability over time are not sufficiently obtained. In order to improve this, the second embodiment includes the roller 11 that rotates while being in contact with the belt guide member 5, thereby preventing frictional wear due to rubbing of the belt guide member 5 or the conversion means 6 and obtaining reliability over time. be able to.
(Embodiment 3)
FIG. 11 shows a third embodiment of the present invention (hereinafter simply referred to as “Embodiment 3”). The third embodiment differs from the first embodiment only in that the belt guide member 5 has a ball bearing 12 as a rotating member that comes into contact with the inclined surface 6a of the converting means 6 in a stationary state. The ball bearing 12 is provided with its inner race portion fixed to the outer peripheral portion of the belt guide member 5.
[0056]
According to the third embodiment, the belt guide member 5 has the inner race portion of the ball bearing 12 by having the ball bearing 12 in contact with the inclined surface 6a of the conversion means 6 in a stationary state according to the same technical idea as the second embodiment. When the outer race portion of the ball bearing 12 is stationary and is in contact with the inclined surface 6a, the displacement of the shaft end portion of the driven roller 2 is twisted and converted into the downward displacement 2A1. In addition, the direct rotational sliding friction between the belt guide member 5 and the conversion means 6 is eliminated, and the frictional wear due to the rubbing of the belt guide member 5 or the conversion means 6 can be prevented, and reliability over time can be obtained.
(Embodiment 4)
FIG. 12 shows four embodiments of the present invention (hereinafter simply referred to as “embodiment 4”). In the fourth embodiment, the displacement of the shaft end portion of the driven roller 2 is twisted and smoothly converted into the downward direction 2A1 while contacting the outer race portion of the ball bearing 12 instead of the conversion means 6 as compared with the third embodiment. The only difference is that the roller 13 as a rotation guide member is provided. The roller 13 is made of, for example, metal and is formed integrally with the roller shaft 13a. The roller 13 is rotatably supported by a support member 14 fixed to the side plate 10 by fastening means such as screws via a roller shaft 13a.
[0057]
According to the fourth embodiment, in addition to the advantages of the third embodiment, when the belt guide member 5 moves in the direction of the axis 2a while rotating together with the inner race portion of the ball bearing 12, the outer race portion of the ball bearing 12 is stationary. Thus, the roller 13 rotates in the counterclockwise direction in FIG. 12, and the displacement of the shaft end of the driven roller 2 is twisted and smoothly converted into the displacement in the downward direction 2A1, so that the belt guide member No direct rotational rubbing between the roller 5 and the roller 13 is eliminated, and rubbing wear due to rubbing of the belt guide member 5 or the roller 13 can be prevented more reliably, and reliability over time can be obtained.
[0058]
The fourth embodiment is not limited to that shown in FIG. 12, and the ball bearing 12 is removed if it is not necessary to prevent frictional wear due to rubbing of the belt guide member 5 or the roller 13. At the same time, the belt guide member 5 is formed large up to the outer case portion of the ball bearing 12, and the roller 13 is rotated while the rotating belt guide member 5 is in contact with the roller 13. The displacement may be smoothly converted into the displacement in the downward direction 2A1 by twisting (an embodiment according to the invention of claim 6).
(Embodiment 5)
FIG. 14 shows a fifth embodiment (hereinafter simply referred to as “embodiment 5”) of the present invention. In the fifth embodiment, the belt slip prevention means 19 including the first to fourth embodiments described above is applied to a belt fixing device 20 as shown in FIG.
[0059]
In FIG. 14, the heating roller 22 as a heating member for heating the fixing belt functions as a driven roller 2 having a heat source 22 </ b> A therein, and the fixing roller 21 as a fixing member functions as a driving roller 1. The fixing belt 23 that fixes the unfixed toner on the recording paper functions as the belt 3. The fixing roller 21 is provided with a pressure roller 25 as a pressure member that forms a fixing nip portion 26 in pressure contact with the fixing roller 21 via the fixing belt 23. The shaft end portion of the heating roller 22 is provided with a belt slip prevention means 19 having the above-described series of configurations.
[0060]
Reference numeral 24 denotes a pair of springs disposed on both sides of the shaft end of the heating roller 22 so as to stretch the fixing belt 23 with a predetermined tension P2. Reference numeral 29 is a pair of pressure springs disposed on both sides of the shaft end portion of the pressure roller 25 so as to press the pressure roller 25 against the fixing roller 21 through the fixing belt 23 with a predetermined biasing force P1. is there. By this pressure spring 29, the pressure roller 25 is urged in a direction in which the pressure roller 25 is pressed against the fixing roller 21 via the fixing belt 23. The urging force P1 of the pressure spring 29 is set sufficiently larger than the tension P2 of the spring 24.
[0061]
In particular, since the fixing belt 23 requires heat resistance and thermal responsiveness, the fixing belt 23 is formed by providing a release layer on a film-like substrate such as polyimide, nickel, stainless steel, or iron, and its thickness is It is desirable to use a thing in the range of 30-300 micrometers. However, the strength of such a thin fixing belt 23 decreases when subjected to thermal stress, and wrinkles and buckling due to the belt are more likely to occur than when used at room temperature. There is a problem that the side ends are easily cracked. This time, the belt fixing device 20 provided with means for preventing belt deviation and reducing belt deviation force is realized, and the durability of the fixing belt 23 is improved by eliminating crack damage at the side edge of the belt and the fixing belt 23. We were able to improve.
(Embodiment 6)
FIG. 15 shows a sixth embodiment of the present invention (hereinafter simply referred to as “Embodiment 6”). The sixth embodiment is parallel to the fixing roller 21 and the pressure roller 25 on the inner peripheral surface side of the fixing belt 23 between the heating roller 22 and the pressure roller 25 with respect to the belt fixing device 20 of the fifth embodiment. Moreover, the only difference is that the belt fixing device 30 is provided with a guide member 31 that contacts the inner peripheral surface of the fixing belt 23. The guide member 31 is a cylindrical roller member made of, for example, a cylinder.
[0062]
In the sixth embodiment, the heating roller 22 is provided as the driven roller 2 that prevents the belt from shifting. When the belt slip prevention means 19 acts to prevent the belt slippage, one side of the heating roller 22 that is the driven roller 2 is displaced (in the sixth embodiment, it is displaced in the vertical direction of the twisting upward direction 2A2 and the twisting downward direction 2A1). The recording paper (not shown in FIG. 15) on which an unfixed image is formed is conveyed to the fixing nip portion 26. In such a state, the fixing nip entrance portion 26a of the fixing nip portion 26 formed by the fixing belt 23 and the pressure roller 25 is not parallel to the axis of the fixing roller 21 as the main drive member. Therefore, there is a possibility that the recording paper is fed obliquely at the fixing nip portion 26 and wrinkles and jams are likely to occur at the fixing portion.
[0063]
Therefore, in the belt fixing device 30 of the sixth embodiment, in order to prevent such a problem, the leading end of the recording paper enters between the heating roller 22 and the pressure roller 25 so that the leading end of the recording paper enters the fixing nip entrance portion 26a in parallel. A guide member 31 that is in parallel with the fixing roller 21 and the pressure roller 25 and is in contact with the inner peripheral surface of the fixing belt 23 is provided on the inner peripheral surface side of the fixing belt 23.
(Embodiment 7)
FIG. 16 shows a seventh embodiment of the present invention (hereinafter simply referred to as “Embodiment 7”). The seventh embodiment is different from the sixth embodiment only in that a belt fixing device 40 in which the following conditions are added to the belt fixing device 30 of the sixth embodiment is provided. That is, as shown in FIG. 16, the fixing belt conveyance speed V1 of the fixing belt 23 and the conveyance apparatus conveyance speed V2 of the conveyance apparatus 32 that conveys the recording paper 28 on which the unfixed toner 27 layer is formed in the fixing nip portion 26. Is set so as to satisfy the relationship of fixing belt conveyance speed V1 ≦ conveyance apparatus conveyance speed V2.
[0064]
As described above, in the belt fixing device 40 according to the seventh embodiment, the fixing belt conveyance speed V1 is slower than the conveyance device conveyance speed V2, so that even if the recording paper 28 enters the fixing nip portion 26 in a skewed manner. If the fixing belt conveyance speed V1 for conveying the recording paper 28 in the fixing unit is set relatively low with respect to the conveyance apparatus conveyance speed V2, a force that pulls the recording paper 28 does not act. The advantage that such a problem does not occur can be obtained.
[0065]
As described above, the present invention has been described with respect to specific embodiments including examples, but the configuration of the present invention is not limited to the above-described first to seventh embodiments and the like, and these are appropriately combined. It will be apparent to those skilled in the art that various embodiments and examples can be configured within the scope of the present invention in accordance with the necessity and application thereof.
[0066]
【The invention's effect】
As described above, according to the first and second aspects of the invention, the endless belt provided in at least one of the driven shaft ends moves in the axial direction according to the axial displacement of the driven shaft of the endless belt. A belt guide urging member for urging the belt guide member in the axial center direction provided on at least one of the belt guide member and the driven shaft end, and the driven shaft end can be displaced in a direction perpendicular to the axial direction. And a converting means for contacting the belt guide member and converting the displacement of the belt guide member in the axial direction into a displacement in a predetermined direction perpendicular to the axial direction. A belt shift occurs during rotation, and the belt shift force generated at that time causes the belt guide member provided at at least one of the driven shaft end portions to be pushed to the side end portion of the endless belt, thereby driving the shaft of the driven shaft. When it moves in direction, displaced in a predetermined direction in which the driven shaft is to reduce the belt deviation force through the support means by the action of converting means. At this time, the endless belt is contact-guided along the belt guide member with a small belt shifting force in which the belt shifting force is reduced at a position displaced in the predetermined direction, thereby preventing the belt shifting and at the endless belt side end. It is possible to prevent the belt short-life due to crack breakage at the belt side end caused by contact between the belt portion and the belt guide member.
[0067]
According to the third aspect of the present invention, the rotating member that rotates while being in contact with the belt guide member is provided on the inclined surface of the converting unit, thereby preventing wear due to rubbing of the belt guide member or the converting unit, and reliability over time. Sex can be obtained.
[0068]
According to the fourth aspect of the present invention, the belt guide member has the rotating member that comes into contact with the inclined surface of the converting means in a stationary state, thereby preventing wear due to rubbing of the belt guide member or the converting means, and reliability over time. Can be obtained.
[0069]
According to the fifth aspect of the present invention, the belt guide member has the rotating member that contacts the converting means in a stationary state, and the converting means smoothly converts the displacement of the driven shaft end portion in a predetermined direction while contacting the rotating member. By being constituted by the rotating guide member, it is possible to prevent wear due to rubbing of the belt guide member or the rotating guide member, and to obtain reliability over time.
[0070]
According to the sixth aspect of the present invention, the conversion means is constituted by the rotation guide member that smoothly converts the displacement of the driven shaft end portion in a predetermined direction while being in contact with the belt guide member. Wear due to rubbing of the guide member can be prevented, and reliability over time can be obtained.
[0071]
According to the seventh aspect of the present invention, the supporting means includes a shaft end portion supporting member that supports the driven shaft end portion, and a belt urging member that urges the endless belt to a predetermined position in a direction in which the endless belt is stretched. And an insertion support member having a long hole shape for inserting the shaft end portion support member, the long hole shape is in a direction in which the endless belt is stretched, and the shaft end portion support member is predetermined. By extending in the direction of displacement in the direction, when the driven shaft is displaced between the shaft end support member and the elongated hole shape to prevent belt slippage, the frictional resistance does not exist, so the displacement is smooth. The belt slip prevention effect works reliably.
[0072]
According to the invention described in claim 8, by using the rolling bearing as the shaft end support member, when the endless belt rotates, the driven shaft acts to displace in a predetermined direction due to the tension caused by the belt rotation. Since the shaft end support member is a rolling bearing having almost no frictional resistance, its rotational torque is extremely small. Accordingly, there is no problem that the belt is prevented from acting in an unstable manner while the driven shaft is rotating against the tension acting in the direction in which the driven shaft is stretched, and the belt slippage preventing action is hindered.
[0073]
According to the ninth aspect of the present invention, the endless belt is a fixing belt for fixing unfixed toner on the recording paper, the driven shaft is a heating member for heating the fixing belt having a heat source therein, and the drive shaft is fixed. The belt guide member, the belt guide biasing member, and the support according to claim 1, wherein the pressure guide member is a member and presses against the fixing shaft via the fixing belt to form a fixing nip portion. Since the belt misalignment prevention means comprising the means and the conversion means is applied to the belt fixing device, the effect of preventing damage to the side end portion of the endless belt can be enhanced, and a highly reliable belt fixing device can be realized.
[0074]
According to the tenth aspect of the present invention, the inner surface of the fixing belt between the heating member and the pressure member is in parallel with the fixing member and the pressure member and is in contact with the inner surface of the fixing belt. By providing the guide member, it is possible to prevent wrinkles and jams due to skew of the recording paper.
[0075]
According to the invention of claim 11, the fixing belt conveyance speed of the fixing belt and the conveyance device conveyance speed of the conveyance device that conveys the recording paper to the fixing nip portion satisfy the relationship of fixing belt conveyance speed ≦ conveyance device conveyance speed. As a result, it is possible to prevent wrinkles and jams due to skew of the recording paper.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional front view showing a main part of a belt driving device according to Embodiment 1 of the present invention.
FIG. 2 is a side view of the main part of FIG.
FIG. 3 is a partial cross-sectional front view of the main part showing the operation of the belt driving device according to the first embodiment.
FIG. 4 is a perspective view of a main part of a belt driving device to which the present invention is applied.
5 is a plan view of the belt driving device of FIG. 4 when viewed from the A viewing direction. FIG.
6 is a front view of the belt driving device of FIG. 4 when viewed from the B viewing direction.
7 is a side view schematically showing the configuration of the belt driving device of FIG. 4; FIG.
8 is a graph showing a result of confirming the amount of belt deviation when the end portion of the driven roller is displaced by the same amount under the configuration conditions of the belt driving device of FIG.
FIG. 9 is a partial cross-sectional front view of a main part of a belt driving device in a modification of the first embodiment.
FIG. 10 is a partial cross-sectional front view of a main part of a belt driving device according to a second embodiment.
FIG. 11 is a partial cross-sectional front view of a main part of a belt driving device according to a third embodiment.
12 is a partial cross-sectional front view of a main part of a belt driving device in Embodiment 4. FIG.
FIG. 13 is a side view of the main part when the component arrangement state around the long hole shape of the belt driving device according to the first embodiment is viewed from the outside of the side plate.
FIG. 14 is a schematic side view of a main part of a belt fixing device according to a fifth embodiment.
FIG. 15 is a schematic side view of a main part of a belt fixing device according to a sixth embodiment.
FIG. 16 is a schematic side view of a main part of a belt fixing device according to a seventh embodiment.
[Explanation of symbols]
1 Drive roller
2 Followed roller
2a Axis of driven roller
3 Endless belt (belt)
4 Spring as a belt biasing member
5 Belt guide member
6 Conversion means
6a Inclined surface
7 Rolling bearing
8 Spring as a belt guide biasing member
9 Bearing support plate
10 Side plate as insertion support member
10a Long hole shape
11 Roller as rotating member
12 Ball bearings as rotating members
13 Roller as a rotation guide member
16 Support means
19 Belt slip prevention means
20, 30, 40 Belt fixing device
21 Fixing roller
22 Heating roller
23 Fixing belt
25 Pressure roller
26 Fixing nip
28 Recording paper
2A1 Twist downward direction as a predetermined direction
3A1 Belt direction
3A2 Belt slip reduction direction
V1 Fixing belt transport speed
V2 transport device transport speed

Claims (13)

An endless belt stretched between at least the drive shaft and the driven shaft ;
A belt guide member that is provided at at least one of the driven shaft end portions and moves in the axial direction in response to the axial movement of the driven shaft of the endless belt;
A belt guide biasing member provided at at least one of the driven shaft end portions for biasing the belt guide member in the axial center direction;
Supporting means for supporting the driven shaft end so as to be displaceable in a direction perpendicular to the axial direction;
Conversion means for converting the displacement to the axial direction of the belt guide member in the displacement in a predetermined direction of the axis direction perpendicular to the direction in contact with said belt guide member,
A belt driving device comprising: The belt drive device according to claim 1, wherein
The belt driving device according to claim 1, wherein the converting means has an inclined surface that contacts the belt guide member and guides the driven shaft so as to be displaceable in the predetermined direction . The belt driving device according to claim 2, wherein
A belt driving device characterized in that a rotating member that rotates while contacting the belt guide member is provided on the inclined surface of the converting means . The belt driving device according to claim 2 , wherein
The belt driving device according to claim 1, wherein the belt guide member includes a rotating member that comes into contact with the inclined surface in a stationary state. The belt drive device according to claim 1 , wherein
The belt guide member has a rotating member that comes into contact with the converting means in a stationary state,
The belt drive device according to claim 1, wherein the conversion means is constituted by a rotation guide member that smoothly converts the displacement of the driven shaft end portion in the predetermined direction while being in contact with the rotation member . The belt drive device according to claim 1 , wherein
The belt driving device according to claim 1, wherein the converting means is constituted by a rotation guide member that smoothly converts the displacement of the driven shaft end portion in the predetermined direction while being in contact with the belt guide member . In the belt drive unit according to any one of claims 1 to 6 ,
The support means includes a shaft end support member that supports the driven shaft end, a belt urging member that urges the endless belt to a predetermined position, and the shaft end support. It is composed of an insertion support member having a long hole shape for inserting and supporting a member,
The belt drive device according to claim 1, wherein the elongated hole shape extends in a direction in which the endless belt is stretched and in a direction in which the shaft end support member is displaced in the predetermined direction . The belt drive device according to claim 7 , wherein
A belt drive device using a rolling bearing as the shaft end support member . In the belt drive device according to any one of claims 1 to 8 ,
The endless belt is a fixing belt for fixing unfixed toner on the recording paper;
The driven shaft is a heating member for heating the fixing belt having a heat source therein;
The drive shaft is a fixing member ;
A belt fixing apparatus comprising a pressure member that forms a fixing nip portion by pressing against the fixing member via the fixing belt. The belt fixing device according to claim 9 , wherein
A guide member is provided on the inner peripheral surface side of the fixing belt between the heating member and the pressure member, in parallel with the fixing member and the pressure member and in contact with the inner peripheral surface of the fixing belt. A belt fixing device. The belt fixing device according to claim 9 or 10 ,
A fixing belt conveying speed of the fixing belt and a conveying device conveying speed of a conveying device that conveys the recording paper to the fixing nip portion are:
A belt fixing device satisfying a relationship of the fixing belt conveying speed ≦ the conveying device conveying speed . In the belt drive unit according to any one of claims 1 to 8,
The belt drive device characterized in that the driven shaft and the drive shaft are both rollers. The belt fixing device according to any one of claims 9 to 11,
The belt fixing device, wherein the driven shaft and the drive shaft are both rollers.

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