JP3275627B2 - Belt shift control device and heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt shift control device in a device having an endless belt which is suspended and held between at least two members and is driven to rotate, and a heating device provided with the belt shift control device. About.

[0002]

2. Description of the Related Art As a specific example of an apparatus having an endless belt that is stretched and held between suspension members and driven to rotate, there is a film heating type heating apparatus using an endless belt-like film.

In this apparatus, a heat-resistant thin-walled endless belt is stretched and held between suspension members including a heating element, and is rotated to convey a material to be heated together with the belt. In this configuration, the material to be heated is brought into close contact with the body to be heated, so that thermal energy of the body to be heated is applied to the material to be heated.

In such an apparatus having an endless belt which is stretched and held between the suspension members and driven to rotate, the endless belt is more or less naturally moved toward one side or the other side in the direction of the rotation axis. It moves, causing a phenomenon of displacement.

As a cause of the positional deviation due to the belt shift, the degree of parallelism and torsion of at least two suspension members such as rollers for suspending the endless belt are increased. Has a limit, and it is difficult to prevent the above-described belt position shift only by improving the accuracy.

Therefore, there is a detection ring type device as one of the belt deviation control devices for automatically controlling the positional deviation due to the belt deviation movement within a predetermined allowable range.

[0007] This is a belt shift detecting member (rotatably supported by at least one end of at least one suspended tension member (roller) on which the endless belt is stretched) and in contact with the widthwise end of the belt. Hereinafter, it is referred to as a detection ring.)
And belt tensioning member displacement means (roller end displacement means) for converting torque (rotational force) due to contact of the detection ring with the rotating belt end into displacement of the suspension tensioning member. The belt shift is controlled by converting the rotational force of the detection ring due to the contact with the belt into linear motion, displacing the suspended tension member and relatively moving it to a balanced position.

[0008] This detection ring type belt deviation control device does not require any special means as the belt position detection means (detection ring) and the belt tensioning member displacement means.
It is simple and has high control reliability.

[0009]

However, the above-described belt shift control device has the following problems.

Even if the coefficient of friction between the belt and the detection ring is not large, in order to obtain a sufficient rotational force of the detection ring for the deviation control, the deviation detection ring must have a tapered open shape, that is, the outer diameter of the detection ring must be reduced. Although a taper that is enlarged from the inner end to the outer end is used, if the taper opening is too large, there is a problem that the belt is damaged such as wrinkles or streaks.

Particularly, in the heating apparatus of the film heating system as described above, since the belt to be used is required to be heat-resistant and have a small heat capacity, the belt is usually used as a belt.
A polyimide product having a thickness of about 70 μm is used. In such a belt, since the coefficient of friction between the belt and the detection ring is not large, a sufficient rotational force of the detection ring for deviation control may not be obtained.

[0012] For this reason, it is setting a large above-mentioned tapered opening amount of detection ring, because belt is a material that does not stretch very thin, or Tsu want wrinkles and streaks is entered, for use in a long period of time of heating state, There were inconveniences such as that only the end of the belt was stretched. Conversely, if the taper opening is too small, a sufficient rotational force cannot be obtained, and the endless belt will be cut off.

More specifically, in the case of a film heating type heating device using a thin endless belt, etc., when the belt deviation control is performed by a detection ring type belt deviation control device, sufficient rotation for operating the deviation control system is performed. In order to obtain the force, the detection ring needs a certain amount of taper opening more than a certain amount, but the belt may be damaged due to generation of wrinkles or streaks, so that the detection device may be damaged by the heating device. It was difficult to use the control device.

In view of the above, the present invention relates to a belt deviation control device as described above, which is configured so as to obtain sufficient rotational force of a detection ring to control the belt deviation without damaging the belt, and to improve the durability of the belt. It is an object of the present invention to provide a belt capable of performing good belt deviation control while improving it.

[0015]

SUMMARY OF THE INVENTION The present invention is a belt shift control device and a heating device characterized by the following constitutions.

(1) A belt shift control device in a device having an endless belt that is suspended and held between at least two members and is driven to rotate, wherein at least one of the belt suspended and held members is a roller A belt shift detection member that is rotatably supported independently of the roller at at least one shaft end of the roller, and is connected to the belt shift detection member that contacts the width direction end of the belt; A roller end for displacing the shaft end of the roller in a predetermined direction by converting the rotational movement into a linear movement when the end of the endless belt is brought into contact with the belt deviation detecting member and a rotational torque is applied to the rotational torque. The belt deviation detecting member has a taper angle continuously smaller toward an end at an inner end of a region where the widthwise end of the belt contacts.
Belt skew controller, wherein the Kunar.

[0017]

[0018] (2) a region widthwise end portion of the belt of the belt shift detecting member contacts is characterized by having a taper angle Gaze <br/> b becomes part component in the widthwise end portions (1) Symbol placement of belt skew controller.

(3) A heating device having an endless belt that is suspended and held between at least two members and is driven to rotate, and heats the material to be heated via the belt or by the heat generated by the belt itself. And a heating device comprising the belt shift control device according to (1) or (2) .

[0020]

In other words, for the belt deviation detecting member (detection ring), the maximum taper amount and the maximum taper angle at which the belt is not damaged are determined based on the material and thickness of the belt used, and the torque can be extracted as much as possible within the range. First, take a large taper angle, and the end of the belt in the width direction comes into contact.
The taper angle continuously increases toward the end at the inner end of the region
Try to be smaller . This allows you to use a thin belt
Even wrinkles and damage to the belt can be prevented. Since the contact pressure of the belt increases at a large taper angle and a large frictional force is generated, it is possible to obtain sufficient torque to control the belt deviation while preventing the belt from being damaged, and to stably maintain a large roller displacement. The force can be obtained, and stable belt deviation control and latitude for belt deviation can be increased.

[0021]

【Example】

<Embodiment 1> (FIGS. 1 to 4) FIG. 1 is a partial cutout of a main part of a film heating type heating device (image heating fixing device) using a detection ring type belt shift control device according to the present invention. FIG. 2A is a perspective view, FIG. 2A is a side view thereof, and FIG.

(1) Overall Schematic Configuration of Apparatus 1 is an endless rotating belt, and a left driving roller 2 as a belt stretching member arranged substantially in parallel with each other;
The right driven roller 3 is suspended between the three members 2, 3, 4 of the heating element 4 disposed below between the two rollers.

The rotating belt 1 is a film of a heat-resistant resin such as a polyimide resin having a thickness of 10 to 100 μm, and a fluorine-based release layer having a thickness of 5 to 20 μm is formed on the outer peripheral surface. The length is about 60 to 300 mm.

The drive roller 2 has a diameter of 10 to 30 mm and has a high friction layer such as a heat-resistant rubber on its surface. 2d
Is a roller shaft whose front and rear end shaft portions are rotatably supported by bearings 2a and 2b fixed to side walls of a device frame (chassis) (not shown). Reference numeral 2c denotes a gear attached to a shaft portion on the rear end side of the roller 2, and a rotational force is transmitted to the gear 2c from a drive source (not shown) to rotate the roller 2.

The driven roller 3 has shafts 3a and 3b rotatably supported at both front and rear ends of a roller shaft 3c by bearings 3a and 3b.

A bearing 3b on the rear end side of the driven roller 3 is fixed to a side wall of the apparatus frame (not shown), but a bearing 3a on the front end side.
Is provided with a degree of freedom of movement substantially in the vertical direction A and B and the spring 5
It is a movable bearing that is suspended and supported. A spring 6 for applying tension to the rotating belt 1 is applied to the movable bearing 3a using the driven roller 3 as a tension roller.

The heating element 4 is an elongated low-heat-capacity linear heating element whose longitudinal length is in the belt width direction orthogonal to the rotation direction C of the rotating belt 1, and for example, has high heat resistance such as alumina (Al ₂ O ₃ ). Electrically insulating elongated ceramic substrate (heater substrate)
Is a ceramic heater in which a current-generating resistor layer is formed in a narrow band shape on a surface of the substrate by printing or the like, and a current-carrying electrode portion is provided at both ends thereof. Generally, a thin surface protective layer such as a heat-resistant glass layer is provided on the surface of the ceramic heater. The heater 4 is fixedly supported by a stationary support member 8 via a heat insulating member 7.

Reference numeral 9 denotes a pressing roller having a silicone rubber layer or the like as a pressing contact member for pressing the rotating belt 1 against the heating element 4, and both ends of the roller shaft 9d on the front end side and the rear end side. The shaft is rotatably supported between movable bearings 9a and 9b, which are arranged with a degree of freedom in the vertical direction, and both bearings are lifted and urged by springs 9c. The pressure roller 9 rotates the rotating belt 1
And pressurizedly contact the heating element 4 with a predetermined pressure.

The rotating belt 1 is maintained in a state of being stretched between the driving roller 2, the driven roller 3, and the heating member 4 by the tension roller action of the spring 6 of the driven roller 3, and the driving roller 2 is driven to rotate. As a result, the inner surface of the rotating belt 1 slides in close contact with the surface of the heating element 4 by the frictional force between the outer peripheral surface of the driving roller 2 and the inner peripheral surface of the rotating belt 1 while maintaining a predetermined peripheral speed in the clockwise direction C in the drawing. It is driven to rotate. The pressure roller 9 rotates following the rotation of the rotating belt 1.

In order to reduce the contact sliding load between the inner surface of the rotating belt 1 and the surface of the heating element 4 during the belt rotation and to prevent the inner peripheral surface of the belt from being scraped, heat-resistant grease ( Often coated with fluorine grease.

The rotating belt 1 by the driving roller 2
When the heating member 4 is driven to rotate and the heating element 4 is heated to a predetermined temperature by energization, recording as an object to be heated on which an unfixed toner image t is formed and carried from an image forming unit (not shown) side. When the material P is introduced between the pressurizing roller 9 and the rotating belt 1 of the press-contact nip portion (fixing nip portion) N between the heating member 4 and the pressurizing roller 9, the recording material P It is in close contact with the outer surface, is pressed against the heating element 4, and passes through the pressure nip N in an overlapping state with the rotating belt 1.

In the process of passing through the pressure nip, the heat of the heating element 4 is applied to the recording material P via the rotary belt 1 so that the unfixed toner image t on the recording material P is heated and fixed. The recording material P passes through the pressure nip N and is separated from the surface of the rotating belt 1 and discharged.

(2) The belt deviation control device 11 is disposed on the front end side of the driven roller 3 so as to be freely rotatable about the shaft 3c coaxially with the driven roller and supported by the widthwise end of the rotating belt 1. A belt detection ring as a belt shift detection member.

The detection ring 11 has an inner end surface 11a.
Is substantially in contact with the front end face 3d of the driven roller 3, and has a diameter substantially the same as that of the driven roller 3 so as not to apply an extra force to the rotating belt 1, and has a diameter gradually increasing outward. From the inner end face 11a to the outer end face 1 as a whole.
1b, a tapered shape whose diameter becomes slightly larger, and the tapered portion (tapered portion) 11
c is in contact with the widthwise end of the rotating belt 1.

As will be described later, the tapered portion 11c has a diameter increasing portion (a portion having a large taper angle) where the rate of increase in the outer diameter is large.
1 and a diameter flat portion (a portion where the taper angle is small or a portion where the taper angle is zero) c2 where the increase rate of the outer diameter is small.

The outer end surface 11b of the detection ring 11
A cylindrical portion 12 having an outer diameter smaller than the diameter of the driven roller 3 is provided integrally with the detection ring 11 and concentrically with the shaft 3c.

The control belt 13 is wound around the outer periphery of the cylindrical portion 12 with one end 13a fixed to the cylindrical portion.
The other end 13b of 3 is locked and fixed to an immovable locking member 14 below the cylindrical portion, and a belt portion between the cylindrical portion 12 and the locking member 14 extends substantially vertically. The control belt 13 is a member having flexibility and small tensile elongation. The direction in which the control belt 13 is wound around the cylindrical portion 12 is a direction in which the control ring 13 is wound around the cylindrical portion 12 by a rotational force generated by sliding friction of the detection ring 11 with the rotating belt 1.

When the rotating belt 1 shifts in the direction D (FIG. 1) in the course of its rotation, the width of the end of the belt on the detecting ring 11 increases. Then detection ring 1
1 indicates that the frictional force of the rotating belt 1 is increased,
However, the torque for rotating the detection ring 11 in the direction indicated by the arrow F about the shaft 3c also increases.

Since the control belt 13 is wound around the cylindrical portion 12 by the increase of the driven rotation torque of the detection ring 11, a force for moving the detection ring 11 downward against the lifting force of the spring 5 is generated. Then, the front end side of the driven roller 3 is displaced in the downward direction B with the stationary bearing 3b on the back end side as a fulcrum.

Due to the displacement of the driven roller 3 in the downward direction B on the front end side, the driven roller 3 is twisted at the front rear, and the rotating belt 1 returns and moves in the direction E opposite to the above-mentioned one-sided movement D direction. And balance at a certain position without moving in either direction E or direction D. At this time, the rotating belt 1 and the detection ring 11
, That is, the force that winds the control belt 13 to lower one end of the roller 3 and the force that the spring 5 pulls up.

The displacement of the driven roller 3 is generated by a sliding force corresponding to the width of the rotating belt 1 and the detecting ring 11 and is generated by a force for pushing down the roller front end side and a hanging support for the roller front end side. The spring 5 almost stops at a position where the lifting force of the spring 5 is balanced.

In such a belt shift control device,
Each element 1 for converting the rotational force of the detection ring 11 into a linear motion and displacing the shaft end of the roller 3 in the vertical direction.
Reference numerals 2, 13, 14, 5, and 6 constitute one element of the roller end displacement means, and the above-described operation of the detection ring 11 and the roller end displacement means causes a displacement of the rotating belt 1 due to a one-sided movement. It is automatically controlled to fall within a predetermined allowable range.

(3) Detection ring 11 (FIG. 4). The shape of the tapered portion 11c It is desirable that the rotational force of the detection ring 11 increases as the amount of engagement of the endless rotary belt 1 increases. Therefore, the shape of the tapered portion 11c is appropriately set as shown in FIG. In FIG, theta is a taper angle indicates the inclination with respect to the roller axis direction of the tape path portion 11c. h is the amount of taper and indicates the height from the outer peripheral surface of the roller 3.

In this embodiment, the shape of the tapered portion 11c is such that the taper angle θ of the diameter-increased portion c1 is maximized at the inner end portion and gradually changes gradually, so that the tapered portion is outside the position where the predetermined taper amount h is reached, that is, the diameter. The taper angle θ of the flat portion c2 is set to zero (straight shape).

With such a shape, even in the case of the thin endless belt 1 as in this embodiment, a sufficient frictional force can be obtained, and wrinkles and streaks do not occur on the belt.

[0046] Comparative Experiment (FIG. 3) The inventors conducted a comparative experiment on the tapered shape of the detection ring 11 and found that the rotational torque generated by the frictional force of the detection ring 11 was as shown in FIG.

<Comparative Example 1> A taper angle θ of zero, ie, a straight shape. <Comparative Example 2> A monotonous taper shape with a constant increase rate of the outer diameter. <Example> An increase rate of the outer diameter The tapered shape has a large portion and a small portion, and as a result, <Comparative Example 1> When the ring shape is straight, almost no increase in torque with an increase in the amount of engagement is observed.

Comparative Example 2 In the case of a monotonous taper shape, an increase in torque is observed. However, as in the present embodiment, for example, a polyimide belt 1 having a thickness of 30 μm is used.
In the case of (1), there is a limit to the amount of taper for preventing wrinkles and streaks.

<Embodiment> In the case of the detection ring 11 embodying the present invention, a further increase in torque was observed as compared with Comparative Example 2 having the same taper amount h.

Further, the maximum value of the taper angle θ can be made larger in the tapered portion shape of the detection ring of the present embodiment than in the monotonically tapered detection ring as in Comparative Example 2. Even though h is 0.3 mm, a torque equivalent to a monotonous tapered shape with a taper amount h of 0.5 mm can be obtained.

According to experiments by the present inventors, it has been found that
In the case of using a μm polyimide rotating belt 1,
When the taper amount h was 0.5 mm or more, the rotating belt was damaged. Similarly, when a polyimide rotating belt having a thickness of 30 μm was used, if the taper angle was 1.5 ° or more, the rotating belt was damaged.

In view of these results, the shape of the tapered portion that does not damage the polyimide rotating belt having a thickness of 30 μm is determined.

That is, the maximum taper amount h and the maximum taper angle θ are determined according to the material and thickness of the film to be used, and the maximum taper angle is firstly increased by increasing the taper angle so as to extract as much torque as possible within the range. It is desirable to make it flat from the point where it becomes h.

As a result, a large frictional force is generated due to a large contact pressure at a large taper angle θ, and a large torque can be obtained without breaking the film.

As is apparent from these results, since a high torque can be obtained with a relatively small taper amount h, the torque can be increased without damaging the thin endless belt.

<Embodiment 2> (FIGS. 5 to 7) The shape of the tapered portion of the detection ring according to the present invention is not limited to the shape shown in FIG. 4 of the previous embodiment. I just want it. For example, the same effect can be obtained with a ring shape as shown in FIGS.

The tapered shape shown in FIG. 5 has a diameter increasing portion c1 in which the taper angle θ gradually increases and a diameter flat portion c2 in which the taper angle θ is zero in order from the inside in the taper portion width direction (the direction of arrow Ta in the figure). It has a shape having

The tapered shape shown in FIG. 6 includes, in order from the inner side in the width direction of the tapered portion, a portion where the taper angle θ is gradually increased and a diameter increasing portion c where the tapered angle θ is gradually increased.
1 and a diameter flat portion c2 having a taper angle θ of zero, and the shape of the connection is smooth.

The tapered shape shown in FIG. 7 has, in order from the inner side in the width direction of the taper portion, a shape having a diameter increasing portion c1 in which the taper angle θ increases monotonously and a diameter flat portion c2 in which the taper angle θ is zero. Has become.

Embodiment 3 (FIG. 8) FIG. 8 is a schematic side view of a heating apparatus of the present embodiment.

In this embodiment, a heat-resistant rotating belt 1 is suspended between two suspending members of a driving roller 2 and a heating element 4 and the rotating belt 1 is driven to rotate by the rotation of the driving roller 2. The configuration of the heating device is the same as that of the above-described first embodiment.

The detection ring 1 is provided at one end side of the drive roller 2 of this device in the same manner as provided on the driven roller 3 of the first embodiment.
1, a belt deviation control means including a cylindrical portion 12, a control belt 13, a locking member 14, a spring 5 of a movable bearing 2a, and the like.

However, in the case of this example, when the end of the roller is lowered, the film shifts in that direction. Therefore, the direction of the pulling force by the ring rotation torque T and the direction of the pulling force by the spring 5 are reversed, that is, the ring rotation is performed. The roller end is pulled up by the torque T and lowered by the tension spring 5.

<Embodiment 4> (FIG. 9) In each of the above embodiments, an example is shown in which the rotating belt 1 is suspended between the fixedly supported heating element 4 and the driven roller 3 or the driving roller 2. Although shown, the heating device according to the present invention is not limited to this. For example, a rotating belt (film) having a conductive layer is driven by being suspended between a plurality of suspending members, and the rotating belt is driven by a magnetic field generating means. A so-called electromagnetic induction heating type / film heating type heating device that generates a magnetic field across the conductive layer and changes the magnetic field to generate an eddy current in the conductive layer to generate heat in the rotating belt itself may be used. .

FIGS. 9A and 9B show examples of the configuration of such a heating device.

FIG. 9A shows the lower surface of the assembly (the lower surface of the stay 21) composed of the stay 21, the iron core 22, the exciting coil 23 and the like as the magnetic field generating means, and the drive roller 2.
And a driven roller 3, a rotating belt 1 having a conductive layer between three members is stretched and suspended, and the rotating belt 1 is rotationally driven by a driving roller 2.

As in the first embodiment, a detection ring 11 as a belt shift detecting member and a cylindrical portion 1 as a roller end displacement means are provided at one end of a driven roller 3 of this apparatus.
2, a belt shift control means including a control belt 13, a locking member 14, a suspension spring 5 for the movable bearing 2a, and the like.

(B) shows the lower surface of the stay 21 of the assemblies 21 to 23 and the drive roller 12
A rotating belt 1 having a conductive layer is stretched between the two members, and the rotating belt 1 is driven to rotate by a driving roller 2. Means.

[0069]

As described above, in the belt deviation control device of the detection ring (belt deviation detection member) type, the ring shape of the detection ring is brought into contact with the end in the width direction of the belt.
The taper angle continuously decreases toward the end at the inner end of the area
With fence made shape, even in the device using a thin inextensible material endless belt as the heating apparatus of a film heating type, without wrinkles and streaks in the belt, the detection ring and between the endless belts The frictional force can be made sufficiently large, and the frictional force between the two can be increased as the amount of engagement of the belt with the detection ring increases. As a result, the deviation can be controlled stably, and the rollers involved in the belt deviation control can be largely moved, that is, the roller displacement can be increased, so that the apparatus has an increased latitude with respect to the deviation of the belt. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a heating device according to a first embodiment.

FIG. 2 (a) is a side view, and FIG. 2 (b) is a cross-sectional side view of a main part.

FIG. 3 is a diagram showing the results of a comparative experiment on the tapered portion shape of the belt shift detection ring.

FIG. 4 is a schematic diagram illustrating the shape of a detection ring according to the first embodiment.

FIG. 5 is a schematic view illustrating another shape of the detection ring.

FIG. 6 is a schematic view illustrating another shape of the detection ring.

FIG. 7 is a schematic view illustrating another shape of the detection ring.

FIG. 8 is a side view of the heating device according to the third embodiment.

9 (a) and 9 (b) are side views of other heating devices, respectively.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotating belt 2 driving roller 3 driven roller 4 heating element 5 spring 6 spring 11 detection ring 12 cylindrical portion 13 control belt 14 locking member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-298434 (JP, A) JP-A-4-164740 (JP, A) JP-A-6-308845 (JP, A) 65210 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/20 B65H 5/02 B65G 43/02

Claims (3)

(57) [Claims] 1. A belt shift control device in a device having an endless belt that is suspended and held between at least two members and is driven to rotate, wherein at least one of the belt suspension and holding members is a roller. A belt shift detecting member that is rotatably supported on at least one shaft end of the roller independently of the roller and contacts a widthwise end of the belt; and the belt shift detecting member is connected to the belt shift detecting member. Roller end displacement that displaces the shaft end of the roller in a predetermined direction by converting the rotational motion into a linear motion when a rotational torque acts upon the end of the endless belt in the width direction contacting the deviation detecting member. The belt deviation detecting member has a taper angle that is continuous toward an end at an inner end of a region where the widthwise end of the belt contacts.
A belt shift control device characterized in that it becomes smaller . 2. A mounting according to claim 1 Symbol, wherein the region widthwise end portion of the belt of the belt shift detecting member contacts is to have a part component comprising taper angle Gaze b in the width direction end portion Belt leaning control device. 3. A heating device which has an endless belt which is suspended and held between at least two members and is driven to rotate, and which heats a material to be heated via the belt or by the heat generated by the belt itself. A heating device comprising the belt shift control device according to claim 1 or 2 .