JP3093589B2 - Endless film shift prevention mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus having an endless film (or an endless belt member) which is wound around at least two suspended tension members, and which rotates during the rotation of the endless film. The present invention relates to a mechanism (a shift control mechanism, a shift control mechanism) for preventing a shift in a film width direction (a film rotation axis direction) crossing a film rotation direction along a hanging tension member.

[0002]

2. Description of the Related Art As an apparatus having an endless film that is wound around at least two suspended tension members and rotates, for example, there is a film heating type heating apparatus. This heating device is known, for example, from JP-A-63-313182. One embodiment of the heating device is shown in FIG.

A horizontally long heating element 4 whose longitudinal direction is perpendicular to the paper surface is, for example, a low-heat-capacity heater in which a conductive heating pattern is printed on the surface of a ceramic substrate, and is supported via a heater holder 4a made of a heat insulating material. It is arranged fixed to the stay 4b.

The driving roller 2 and the driven roller (tension roller) 3 are disposed substantially parallel to the heating element 4 with their respective shaft portions rotatably held between bearings (not shown). The drive roller 2 has a diameter of, for example, 10 to 30 mm,
The surface layer has a heat-resistant rubber layer. A drive source M for a rotary drive system of the drive roller 2 is provided.

[0005] An endless film 1 suspended and stretched between three members of the above-mentioned driving roller 2, driven roller 3, and heating element 4.
Is, for example, a heat-resistant resin film such as polyimide,
10 to 80 μm thick, 5 to 20 μm on the outer surface
And a circumference of about 60 to 300 mm.

There is provided a pressure roller 5 made of silicon rubber or the like and pressed against the heating element 4 with the endless film 1 interposed therebetween.

When the driving source M is urged and the driving roller 2 is driven to rotate clockwise as indicated by an arrow in the drawing, the frictional force between the outer peripheral surface of the driving roller 2 and the inner peripheral surface of the endless film 1 causes the endless film 1 to move. The driving force is transmitted, and the endless film 1 is rotated between the driving roller 2, the driven roller 3, and the heating member 4 in the clockwise direction indicated by the arrow in the drawing.

[0008] The film 1 is pressed against the heating element 4 by the pressure roller 5, and the film 1 rotates while its inner surface is in close contact with the surface of the heating element 4 and slides. Pressure roller 5
Rotates following the rotation of the film 1.

In a state where the endless film 1 is driven to rotate and the heating element 4 generates heat by energization and is controlled to a predetermined temperature, an endless film of a pressure contact portion (heating section) N between the heating element 4 and the pressure roller 5 is provided. The heated material P is introduced between the pressure roller 1 and the pressure roller 5, and the pressurized portion N is pinched and conveyed together with the endless film 1 to heat the heated material P by the heat of the heating element 4 via the endless film 1. To be processed. The conveyance guide member 20 for the material P to be heated is
This is a guide member for the front and rear materials P to be heated.

[0010] Such a film heating type heating device is, for example, a copying machine, a laser beam printer (LB).
P), in an image forming apparatus such as an electrostatic printer, an image heating and fixing device for a recording material P as a heated material on which an unfixed toner image to be fixed is formed and supported;
Equipment to improve surface properties by heating
It can be effectively used widely as a means or a device for heat-treating a material to be heated.

A heat roller type heating device, which has been widely used as an image heating and fixing device in an image forming apparatus, has a large heat capacity of the heat roller. Therefore, a weight for starting the roller to a predetermined fixing temperature is required. It takes a long time and it is necessary to supply power so as to maintain the startup temperature even when the image forming apparatus is not used (during standby). 4. Since both the endless films 1 can use very small heat capacities and the temperature rises quickly, even if the temperature of the fixing device is the same as room temperature during standby of the image forming apparatus, the heating element 4 The heating element 4 and the endless film 1 immediately rise to a predetermined fixable temperature by energizing to It has excellent features, such as the fact that the power consumption of the fixing device during standby can be reduced to zero, saving power, shortening the wait time, and suppressing the temperature rise inside the image forming apparatus. .

By the way, as in the film heating type heating device or the image heating fixing device of the above example, at least two
One or more film tensioning members, ie, drive rollers 2,
In an apparatus having the endless film 1 suspended and rotated between the driven roller 3 and the heating element 4, the endless film 1 is driven while the endless film 1 is suspended during the rotation of the endless film 1. Roller 2,
Along the driven roller 3 and the heating element 4, it becomes larger or smaller to one end side or the other end side in the film width direction orthogonal to the film rotation direction, and tends to move naturally.

As a factor of the positional deviation due to the one-sided movement of the film, the parallelism and the twist between the above-mentioned members for suspending the endless film 1 can be cited. Therefore, it is difficult to prevent the above-mentioned movement toward the film only by improving the accuracy.

One of the means for preventing or controlling the shift of the endless film 1 is a film shift detecting ring in which the end of the endless film is attached to one end of a member around which the endless film 1 is stretched. The endless film 1 slides on the shift detection ring in accordance with the width of the end of the endless film 1 with respect to the shift detection ring, which varies with the shift of the endless film 1 during the rotation of the endless film. The endless film 1 is converted by converting the rotational force (rotating torque) due to the moving force into linear motion and relatively moving the film suspending and stretching member to a balanced position.
There is something to control the approach.

FIGS. 5 to 8 show specific examples. This example is applied to the film heating type heating apparatus shown in FIG.

The driven roller 3, which is one of the film hanging and stretching members, has a shaft portion on the rear end side rotatably supported by a free bearing (not shown), and a shaft portion 3a on the front end side swings. Bearing 7
Is rotatably supported.

The oscillating bearing 7 is urged by a pressing spring 8 so as to bias the driven roller 3 in the direction in which the endless film 1 is stretched, and the oscillating bearing 7 of the driven roller 3 is pressed.
The side is biased up by a tension spring 10 so as to bias the side in the lifting direction.

A ring 6 as a film shift detecting member, which is rotatably provided concentrically on the shaft 3a of the driven roller 3 on the side of the swing bearing 7, is fitted. The end face 6a of the ring 6 on the back side (the side near the center in the width direction crossing the running direction of the endless film 1) is almost in contact with the end face on the front end side of the driven roller 3, and has substantially the same diameter as the driven roller. belongs to. On the front end surface of the ring 6, a cylindrical control belt winding portion 11 having an outer diameter smaller than the diameter of the driven roller 3 is provided integrally with the ring 6 and concentrically with the shaft 3a. The edge on the front end side of the endless film 1 suspended by the driven roller 3 is applied to the ring 6, and a width W is applied.

One end 9a is fixed to the outer surface of the control belt winding section 11, and the other end 9b is locked to a stationary locking section 21 (for example, a side plate (not shown)) below the control belt winding section 11. Thus, a control belt 9 is provided. The control belt 9 is a member having flexibility and small tensile elongation. The direction in which the control belt 9 is wound around the winding section 11 is a direction in which the ring 6 is wound around the winding section 11 by a rotational torque generated by sliding friction of the ring 6 with the endless film 1.

When the driven roller 3 swings about the rear free bearing, the lower limit stopper member 12 and the upper limit stopper member 13 that determine the movement limit of the swing bearing 7 are at positions where the swing of the driven roller 3 can be controlled. It is provided. This position is the driven roller 3
It is only necessary that the force is in a range in which a force for swinging back is generated at the stroke end of the swing bearing 7 when swinging.

Next, the operation will be described. When the driving source M is urged and the driving roller 2 rotates, the endless film 1 is moved to the position shown in FIG.
When the vehicle travels in the direction indicated by the arrow, the driven roller 3 is driven to wind, and the ring 6 and the endless film 1 slide.

In the rotation driving process of the endless film 1, the endless film 1 moves toward the back end side direction B in the film width direction, and the width (hanging amount) W of the endless film 1 with respect to the front end side ring 6 is small. When this happens, the frictional force between the endless film 1 and the ring 6 becomes small, and therefore, the rotational torque T acting on the ring 6 is also small.

For this reason, the tension of the tension spring 1 is larger than the control belt winding force of the winding unit 11 by the rotation torque T.
0, the force F by which the front end side of the driven roller 3 is pulled up.
Becomes larger, the front end side of the driven roller 3 is displaced upward U with the swivel bearing on the rear end side as a fulcrum, and the driven roller 3 is moved forward and backward with respect to the axis of the drive roller 2 and the heating element 4 by this displacement. Twist occurs. In this state, the endless film 1 returns and moves to the front end side direction A in the film width direction opposite to the back end direction B in the film width direction.

As the endless film 1 returns to the front end side direction A, the width W of the endless film 1 with respect to the ring 6 increases, and the frictional force between the endless film 1 and the ring 6 increases. The acting rotational torque T also increases.

The increase in the rotational torque T increases the control belt winding force of the winding unit 11. The pulling force of the driven roller 3 on the front end side by the control belt winding of the winding unit 11 is increased by the tension spring 10. If the pulling force F is larger than the pulling force F, the control belt 9 is wound around the winding unit 11, so that the front end side of the driven roller 3 is pulled down around the bearing at the back end against the tension spring 10 and is lowered. Displaced to LW.

Due to the displacement of the driven roller 3 toward the lower side LW on the front end side, the driven roller 3 is twisted at the back of the axis of the driving roller 2 and the heating element 4 in the opposite direction to the state shown in FIG. Occurs. In this state, the endless film 1 returns and moves in the back end direction B in the film width direction opposite to the front end direction A in the film width direction.

That is, the ring 6 is the endless film 1
The rotation torque T is applied by the frictional force with the ring 6, and the rotation torque T is determined by the width W of the film applied to the ring 6.
Changes, and the larger the film width W is, the larger the ring 6 becomes.
The rotation torque T increases, and the control belt winding force of the winding unit 11 increases.

The front end side of the driven roller 3 is displaced up and down U · LW due to the magnitude relationship between the winding force and the pulling force F of the tension spring 10, thereby controlling the leaning directions A and B of the endless film 1. It is.

Thus, the upper U on the front end side of the driven roller 3
In the process of displacing to the lower side or the process of displacing the lower side, when the pulling force F of the driven roller at the front end side by the tension spring 10 and the pulling down force at the front end side of the driven roller by the control belt winding force of the winding unit 11 are balanced. is there. At this time, the driven roller 3 is in a stationary state at a position where the endless film 1 is close to the endless film 1, and the endless film 1 stops moving and moves to a fixed position.

If the machine is installed obliquely or if the apparatus is used for a long period of time, the endless film 1 may deviate from the range of the ring 6, and in this case, as shown in FIG. Alternatively, a film position detecting means 3 having a sensor 30c such as a photo-interrupter by contacting the tip of an arm 30a having a root rotatably supported by a shaft 30b at a rear end side thereof with a spring force (a spring is not shown).
If the endless film 1 deviates from the range of the ring 6 by detecting the deviation amount of the endless film 1 due to 0, an error is displayed and the machine is stopped.

[0031]

In the prior art described above, the pulling force F on the front end side of the driven roller by the tension spring 10 for control balances the pulling force due to the ring torque generated in the ring when the endless film slides on the ring. The position was at a certain film width, that is, a state where the endless film was hung on the ring. Therefore, the endless film deviation control range is always within the area of the ring, and when the end of the endless film comes off the ring, the film position detecting means 3 shown in FIG.
An error was displayed by 0 and the machine was stopped. But,
When the shift control range of the endless film is set to the area of the ring, the end of the driven roller must be pulled up by a spring under the state that the endless film is on the ring.
However, the ring torque changes slightly between the state where the ring torque is stopped from the previous night and the engine is started first in the morning and the state after the heat run in which the heating element is heated. In addition, the ring torque may change due to factors such as the frictional force between the endless film and the ring, the temperature of the endless film and the ring, and the change in the coefficient of friction caused by the ring being rubbed against the endless film and cut off. Since the pulling force by the tension spring 10 is constant for a certain displacement, when the ring torque gradually increases, the driven roller cannot be pulled up within the deviation control range, and an error is generated based on the detection by the film position detecting means 30. Then, there was a problem that the machine stopped.

Since it is necessary to select the tension spring 10 for control in consideration of the magnitude of the ring torque, it is difficult to select the tension spring 10 because the spring force of the tension spring 10 varies for each unit. Further, since the pulling-down force and the force of the tension spring 10 must be balanced based on the ring torque while the endless film is on the ring, it is necessary to attach a strong spring. For this reason, when the ring torque is reduced due to the temperature of the endless film and the ring, the ring being scraped by the endless film, or the like, the force becomes smaller than the tension spring force, and the driven roller cannot be lowered in some cases.

It is an object of the present invention to provide a durable endless film shift prevention mechanism corresponding to an increase in frictional force of a film shift detection member when a shift control target position is at an intermediate position of the shift detection member. And

[0034]

According to the present invention, the shift control range of the endless film is determined not only in the area on the ring (film shift detecting member) but also in a position slightly deviated from the ring toward the driven roller. I do. Thereby, when the ring torque gradually increases, even if the pulling-down force of the driven roller (suspension member) by the ring torque is stronger than the pulling-up force by the control tension spring, if the endless film comes off the ring, Since the driven roller pulling-down force is only a force based on the own weight (constant) of the driven roller, if the tension force of the tension spring is larger than the pulling force based on the own weight of the driven roller, the pulling-up force can be raised without fail. Therefore, the driven roller end can always be pulled up within the deviation control range, so that the machine does not stop due to the error display.

Further, it is sufficient to select a tension spring having a sufficient force to pull up the driven roller against the force based on the weight of the driven roller, and it is not necessary to consider the pulling-down force based on the ring torque. Selection becomes easy.

As a result, the tension spring for controlling the required minimum force can be used, so that the force for lowering the driven roller by the ring torque can be reduced, and the driven roller can be reliably lowered.

The first invention related to the present application is an endless
Film and at least the film is passed over
Also two film suspension tension members and at least one front
At least one end of the film tension member is rotatable
The film shift detecting member supported by the
The film leans on the film shift detecting member and is
The rotational torque acts on the film shift detecting member due to frictional force.
When the rotational movement of the film deviation detecting member is
Into a predetermined direction.
Means for displacing the film-hanging tension member in the end direction
And the film shift detecting member is a ring.
The filter provided with the film shift detecting member at an end thereof.
The tensioning member is a roller, and the ring is
Endless fill that is rotatably fitted to the shaft of the roller
The ring is a low friction material
Having an inner diameter and an outer diameter made of high friction material.
An endless film shift prevention mechanism characterized by
You .

[0038]

[0039]

[0040]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 This example was carried out in the film heating type image heating and fixing apparatus shown in FIG.
The endless film shift prevention mechanism, except for the following points,
Others are the same as those in FIGS. 6 to 8, and thus the description will not be repeated.

As shown in FIG. 1, the position of the endless film 1 is detected by the film position detecting means 30. In the present embodiment, the film position detecting means 30 detects at the near end 1e of the endless film 1 of the ring 6, but may detect at the opposite end. Endless film 1
Is displayed when the endless film 1 moves in the direction A and exceeds the line of the front side limit position 1a, and when the endless film 1 moves in the direction B and exceeds the line of the back side limit position 1b, an error message is displayed. Stop. Front side limit position 1
The line a is located on the right side of the left end 6a of the ring, and the far side limit position 1b is located on the right side of the right end 6b of the ring. That is, the front end side 1e of the endless film 1
Is located at the front limit position 1a, the endless film 1 is wound over substantially the entire width of the ring 6. When the front end 1e is between the ring right end 6b and the back limit position 1b, the endless film 1 Is not wound around the ring 6. As described above, the endless film 1 is moved from the near-side limit position 1a near the ring left end 6a to the far-side limit position 1b outside the ring 6 by the film position detecting means 30.
It is possible to move between. In this embodiment, the endless film 1 is located closer to the film control target position 1c on the ring 6 between the front side limit position 1a and the rear side limit position 1b. The downward force due to the ring torque at the position 1c and the upward force due to the control tension spring 10 are balanced.

The spring force of the tension spring 10 is proportional to the extension of the spring, and is constant and does not change in the case of a constant extension. However, the force for pulling the end of the ring 6 by the ring torque is due to the friction between the endless film 1 and the ring 6. Because of the force, the temperature of the endless film 1 and the ring 6 and the ring 6
It may change due to various factors such as abrasion. In particular, if the endless film 1 is used for a long time, the frictional force between the endless film 1 and the ring 6 tends to increase, and the endless film 1 moves in a direction in which the width W decreases (direction B). When the endless film 1 is applied to the ring 6 (slightly left of the ring right end 6b), the pulling force based on the ring torque is stronger than the force of the tension spring 10, and the driven roller The three end portions are lowered, the endless film 1 moves in the back end side direction B, and the endless film 1 comes off the ring 6 (right from the ring right end 6b, FIG. 2). At this time, the ring torque becomes substantially O only due to the frictional force between the shaft portion 3a and the ring 6, and the force for pulling down the driven roller 3 is almost only the force based on the own weight of the driven roller 3. That is, when the endless film 1 moves rightward beyond the ring right end 6b, the force for pulling down the driven roller 3 becomes a constant force (a force opposing the tension spring 10 based on the own weight of the driven roller 3). Therefore, even if the endless film 1 is further shifted in the back end side direction B, the force for lowering the driven roller 3 does not change. From this, endless film 1
In order to detect the absolute value of the shift of the endless film 1 by the film position detecting means 30, even if the front end 1e of the endless film 1 is cut obliquely with respect to the running direction of the endless film 1, the limit of the endless film 1 on the back side is limited. The line at the position 1b is set so as to be a position where the endless film 1 is surely removed from the ring 6.

Further, the force of the tension spring 10 may overcome the force of lowering the driven roller 3 by its own weight, and the force of the driven roller 3 may be sufficient to raise the driven roller 3 without fail. Thus, a tension spring having a minimum necessary force can be selected without considering the magnitude of the ring torque.

[Second Embodiment] According to the first embodiment, the target position of the film shift control of the endless film may be offset toward the film suspension extending member of the film shift detecting member. However, in this case, the frictional force increases due to abrasion of the film shift detecting member, and the endless film moves to the film suspending member side as in the first embodiment in a more durable and faster manner than in the first embodiment. However, over a longer period of time, the film shift detecting member has come to lose the frictional force with the endless film due to wear,
The endless film moves from the film hanging and stretching member side to the film shift detecting member side.

The second embodiment corresponds to the case where the target position of the film shift control is offset toward the front end side of the ring, and the durability of the machine in the course of such a process is to be increased. Is what you do.

The second embodiment is implemented in the image heating and fixing apparatus of the film heating system shown in FIG. 4 described above, and the mechanism for preventing the endless film from shifting is shown in FIGS.
Since it is the same as that of FIG. 8, the description will not be repeated. FIG. 3 is a longitudinal sectional view of the ring portion. In the driven roller 3, a ring 6 is rotatably fitted to a shaft portion 3a having a reduced diameter. The ring 6 is formed by vulcanizing a ring-shaped outer diameter portion 32 such as rubber on the outer periphery of a low-friction sleeve-shaped ring inner diameter portion 31, and has a tapered portion 32f whose diameter is reduced toward the right end 6b of the ring.
It has a cylindrical shape. The diameter of the small end of the tapered portion 32f is the same as that of the driven roller 3, and the large end of the tapered portion 32f is an arc-shaped bus between the outer peripheral portion of the ring 32 and the cylindrical outer periphery. In this embodiment, the ring outer diameter portion 32 in contact with the endless film 1 is made of a high friction member such as rubber. Accordingly, in a state where the endless film 1 is hung on the ring 6 and a state where the endless film 1 is separated from the ring 6 (to the left of the ring right end 6b) (to the right of the ring right end 6b), the driven roller 3 is moved downward along the line of the ring right end 6b. The difference in lowering force increases. Thus, the endless film 1 can be applied to the ring 6 even if the control spring 10 that can raise the driven roller 3 reliably is applied in a state where the front end side 1e of the endless film 1 is located at the far-side limit position 1b. The left side of the right end 6b) can lower the driven roller 3 reliably. The ring outer diameter portion 32 has a tapered portion 32f.
And the outer diameter becomes larger from the right end 6b of the ring toward the left end 6a of the ring. Further, when the endless film 1 approaches the ring 6, the ring torque increases rapidly and the follower is reliably driven. The roller 3 can be lowered.

In the above description, the driven roller 3 is made of metal such as iron, and the ring inner diameter portion 31 is made of a material having a low coefficient of friction with respect to the reduced diameter shaft portion 3a of the driven roller 3, for example, a bearing material, bronze, or a hard synthetic resin.

However, if the ring 6 is manufactured integrally with a high friction member such as the ring outer diameter portion 32, the ring inner diameter portion 31 and the driven roller 3 will not slip, and the ring 6 will rotate or be scraped with the driven roller 3. . Therefore, even if the endless film 1 is at the position of the back side limit position 1b (position deviated from the ring 6), the rotation of the driven roller 3 causes the force to rotate the ring 6 and the ring torque does not become zero. Therefore, even if the endless film 1 is applied to the ring 6 (to the left of the right end 6b of the ring) or detached from the ring 6 (to the right of the right end of the ring 6b), the difference in force for lowering the driven roller 3 is not so large. Even if the endless film 1 comes off the ring 6, the force for lowering the driven roller 3 is affected by the ring torque, and the coefficient of friction between the shaft portion 3a and the ring 6 may change due to temperature or the like. In some cases, the driven roller 3 cannot be raised within the range (left of the shift position 1b).

In this embodiment, a bearing member (low-friction member) is used for the ring inner diameter portion 31 to prevent the ring 6 from rotating from the driven roller 3.

[0051]

[0052]

[0053]

According to the first aspect of the present invention, the outer diameter portion of the ring is formed with a high friction portion and the inner diameter portion is formed with a low friction portion.
When it is hung on the ring, it can rotate the ring reliably
As a result, the difference in the force to lower the roller between the state where the endless film is applied to the ring and the state where the endless film is released from the ring within the control range of the film deviation is large, and the endless film is durably securely near the boundary between the ring and the roller. in Ru it can be controlled.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating the operation of FIG.

FIG. 3 is a longitudinal sectional view of a ring portion according to a second embodiment.

FIG. 4 is a front view showing a schematic configuration of an example of a film heating device.

FIG. 5 is a perspective view of a film shift prevention mechanism.

FIG. 6 is a perspective view of a film shift prevention mechanism.

FIG. 7 is a perspective view illustrating the operation of a film shift prevention mechanism.

FIG. 8 is a perspective view illustrating the operation of the film shift prevention mechanism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 endless film 2 drive roller 3 driven roller 6 detection ring 9 control belt 10 tension spring 11 control belt take-up part 30 film position detection means 31 ring inner diameter part 32 ring outer diameter part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 23/038 B65H 5/02 F16H 7/00 G03G 15/20 101

Claims (1)

(57) [Claims] 1. An endless film, at least two film suspension members on which the film is stretched, and a film rotatably supported by at least one end of at least one of the film suspension members. The shift detection member, the film is applied to the film shift detection member, and when a rotational torque is applied to the film shift detection member by a frictional force with the film, the rotational movement of the film shift detection member is converted into a linear motion. Means for displacing the end of the film suspension tension member in a predetermined direction, the film suspension tension member end displacement means, wherein the film deviation detection member is a ring, and the film deviation detection member is provided at one end. The film hanging and stretching member provided with is a roller, and the ring is an endless end rotatably fitted to a shaft portion of the roller. In deviation preventing mechanism Irumu, said ring deviation preventing mechanism of the endless film and having an outer diameter consisting of the inside diameter portion and the high friction material made of a low friction material.