JP3520949B2 - Belt fixing 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 fixing device for fixing a toner on a recording medium by heating, melting and pressing, and more particularly to a belt fixing device capable of easily removing a jammed recording medium.

[0002]

2. Description of the Related Art Conventionally, a belt fixing method has been widely used in a fixing device of an electrophotographic apparatus. The device shown in FIG. 4 is also one of the fixing devices. In the figure, the cover 103 is formed so as to be rotatable about an axis 103a, and the heating roller 102 is rotatable about an axis 102a provided at the tip of an arm 107 extending from the axis 103a. It is arranged.

An endless conveyor belt 106 is stretched under the heating roller 102, and the pressure roller 10 is provided inside the belt.
4, a driven roller 105, a tension roller 108 for setting the tension of the belt 106, and the like are provided, and a fixing device is provided by these.

A recording medium on which a toner powder image (not shown) is formed enters the belt 106 from the right side and presses the pressure roller 1.
In the pressing area 04, the heating roller 102 and the belt 10
Although the recording medium passes through the nip 6 and is fixed, the recording medium may not be conveyed due to a jam of the recording medium in front of the heating roller 102 due to unevenness of the recording medium end surface or curling.

Therefore, when the recording medium (not shown) is jammed and the recording medium is not fixed in the state shown in FIG. 4B, the cover 103 is rotated counterclockwise about the axis 103a ( heating roller 1 as shown in a)
The surface of 02 and the surface of the belt 106 are separated from each other, and by rotating the cover 103 counterclockwise, it is possible to eliminate the recording medium jammed and stopped on the belt 106.

[0006]

According to the above-mentioned prior art, in the case of a jam, that is, a paper jam, the cover 103 covering the upper side of the heating roller 102 is rotated further upward as shown in FIG. The pressure roller 102 and the pressure roller 104 are separated from each other. However, when the toner image is formed on the upper surface of the recording medium, the heating roller 102 is located on the toner image side of the recording medium as shown in FIG. From the desire to load in the tray, as shown in Figure 2,
Recently, a mechanism has been adopted in which a recording medium after fixing is conveyed to the upper side of the image forming apparatus and is stacked and stored.

When such a device configuration is adopted, in the conventional configuration as shown in FIG. 4, the storage tray has to be disposed above the cover 103, and a jammed recording medium is formed. In order to eliminate the above, it is necessary to open both the cover and the storage tray, which complicates the configuration.

In order to eject the recording medium from the vicinity of the fixing device, the cover or the like is opened to form an appropriate space between the driving members, and then the operator's hand or tweezers is used in the space. , The operation of pulling out the jammed recording medium is performed.

At this time, since power is applied to the driving member and the heating roller generates high heat, the operator's hand, tweezers, or the like may come into contact with the conductive portion or the high heat portion, resulting in electric shock or burns. There is also.

In view of such circumstances, the object of the present invention is to
An object of the present invention is to provide a belt fixing device which has a simple structure and can easily remove a jammed recording medium. Another object of the present invention is to provide a belt fixing device in which the power of the image forming apparatus is cut off only by the operation of opening the opening / closing door.

[0011]

According to the present invention, a recording medium on which toner is superposed is passed between a fixing belt wound by a plurality of rollers and a heating roller, and the fixing belt is arranged in a radial direction of the heating roller. In a belt fixing device configured to be capable of separating operation, a tension roller for applying tension to the belt is provided in the loop of the fixing belt, and a mounting plate is rotatably linked with the separating operation of the fixing belt. The tension roller and a pressure roller that presses the fixing belt in the radial direction against the heating roller are rotatably attached to the mounting plate, and the rotation shafts of the pressure roller and the tension roller are Located on opposite sides of each other about the rotation axis of the mounting plate ,
The mounting plate is urged around its rotation axis, and
The rotary shaft of the tension roller and the tension roller to rotate the mounting plate.
So that they are biased in opposite directions about the axis of motion.
Characterized in that was.

In the present invention, in the loop of the fixing belt,
Since a tension roller for applying a tension to the belt is provided, and the tension roller is configured to be movable in the belt tension releasing direction in conjunction with the separation operation of the fixing belt, the pressing force of the tension roller on the belt. Release, the belt and the heating roller are not in contact with each other,
The pressure roller is set so that the pressing force on the heating roller side does not reach it.

[0013]

The present invention is also configured as described above.
Therefore, as shown in FIG. 1, the rotating shaft 4 of the pressure roller 4
Even if the spring 15 for urging to a is removed, the rotating shaft 4a can rotate by contacting the lower edge of the elongated hole 8b, and the spring 14 can press the heating roller 2 side. ,
The pressing of the belt 6 toward the heating roller 2 side and the pressing of the tension roller 9 can be shared by one spring 14.

Further, there are provided a cleaning unit for pressing the surface of the fixing belt to clean the surface of the fixing belt, and a temperature detecting unit for contacting with the surface of the belt to detect the surface temperature. It is also an effective means of the present invention to interlock with the opening operation of the open / close door disposed on the side surface of the fixing belt device so as to move from the belt surface to the outside of the separation movement range of the fixing belt device during the separation operation. .

In such a structure, the cleaning means and the temperature detecting means are moved from the belt surface to the outside of the separating movement area of the fixing belt device in association with the opening operation of the opening / closing door, so that the fixing operation is performed. When the separated space is formed between the belt device and the heating roller, it does not collide with the moving fixing belt device.

It is also possible to arrange the power switch of the image forming apparatus in the opening / closing operation area of the opening / closing door provided on the side surface of the image forming apparatus, and to cut off the power supply by opening the opening / closing door. Is an effective means. With this configuration, since the power switch is automatically turned off, the power is cut off without any special operation, the power is not continuously applied to the driving member, and the fear of electric shock is eliminated. In addition, the operator's hand does not touch the high-heat part and burns reflexively due to the shock of electric shock.
The high heat of the heating roller naturally cools down after a lapse of an appropriate time after the power is turned off, and the jammed recording medium can be taken out safely.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified, and are simply described. It's just an example.

As shown in FIG. 1, the belt fixing device of the image forming apparatus according to the embodiment of the present invention is provided inside the frame body 10 and the opening / closing door 12 arranged on the side surface of the frame body 10. The heating roller 2, the fixing belt device 3, a mounting plate 8 for bringing the fixing belt device 3 into and out of contact with the heating roller 2, an operating plate 10, and various other mechanisms.

The heating roller 2 is formed by covering the outer circumference of an aluminum tube having a heating element therein with silicon rubber and further winding the outer circumference with a fluorine-based PFA tube so that the circumference is elastic. The roller body is provided with a heating roller gear portion (not shown) on one of the end surfaces of the roller body. In addition, an intermediate gear connected from a drive source (not shown) via a reduction gear train is arranged,
The intermediate gear meshes with the heating roller gear portion so that the heating roller 2 can rotate in the arrow direction.

The fixing belt device 3 is formed of a metallic fixing belt body formed in an endless belt shape, and in the loop of the fixing belt 6, a pressure roller 4, a driven roller 5, and between the both rollers are provided. A fixing roller 9 for applying tension to the loop of the fixing belt 6 is arranged.

The pressure roller 4 in the loop of the fixing belt 6 is formed of a hard member, and a pressure roller gear portion (not shown) is provided on one of the end faces of the roller body. The pressure roller gear portion is configured to rotate the pressure roller 4 in the arrow direction by meshing with the intermediate gear (not shown) connected from a drive source (not shown) through a reduction gear train. The pressure roller gear portion is configured to come into contact with and separate from the intermediate gear by a contacting and separating operation with a heating roller 2 of a fixing belt device 3 described later.

Further, the mounting plate 8 is disposed on a portion (not shown) of the frame body 10 so that the rotary shaft 8a is rotatable, and is biased clockwise by a spring 14. A long hole 8b is formed in the mounting plate 8 on the heating roller 2 side, and a rotary shaft core 4a of the pressure roller 4 is rotatably fitted in the long hole 8b.
A is biased by the spring 15 in the direction of the axis of rotation of the heating roller 2.

A rotary shaft core 9a of a tension roller 9 is rotatably fitted to the opposite side of the rotary shaft 8a from the rotary shaft core 4a. Therefore, the rotating shafts of the pressure roller 4 and the tension roller 9 have the axis 8 of the mounting plate 8.
It is urged in the opposite directions by the urging force (spring 14) about a.

Further, a long hole 8d is formed in the mounting plate 8, and a pin 10a which is planted at one end of an operating plate 10 rotatably arranged around a shaft core 10b is provided in the long hole. A roller 13 is slidably fitted to the other end of the operating plate 10. Further, the operating plate 10 is stopped at the initial position by the stopper 23 against the biasing force of the spring 14 at the solid line position.

Further, on the side surface of the frame body 10 of the image forming apparatus, there is provided an opening / closing door 12 which is openable / closable around a shaft center 12a as a rotation center. A handle 19 and a power switch 20 of the image forming apparatus are provided above the opening / closing door 12, and a cam 11 is provided near the lower rotating shaft core 12a. The side surface 11a comes into contact with the roller 13 arranged on the operating plate 10,
The operating plate 10 and the mounting plate 8 are configured to rotate against the biasing force of the spring 14 to the position of the virtual line.

An arm portion 18 extends to the opening / closing door 12, and a cleaning means 16 for cleaning the surface of the fixing belt 6 by pressing the end portion of the arm portion 18 against the surface of the fixing belt 6.
And a temperature detecting means 17 that comes into contact with the surface of the belt 6 to detect the surface temperature. The both means are moved from the belt surface to the outside of the separation movement area of the fixing belt device by the counterclockwise opening operation of the opening / closing door. Therefore, when the separated space is formed between the fixing belt device 3 and the heating roller 2, it does not collide with the moving fixing belt device.

Next, the operation of this embodiment having the above configuration will be described. In FIG. 1, when the opening / closing door 12 is closed, the power switch 20 of the image forming apparatus is closed, so that power is supplied to each unit. By closing a switch (not shown), the image forming apparatus 1 (FIG. 2)
Operates, and the heating roller 2 and the pressure roller 4 also rotate.

The belt 6 is rotated by the rotation of the pressure roller 4, the surface of the belt 6 is cleaned by the cleaning means 16 provided on the opening / closing door 12, the surface temperature is detected by the temperature detecting means 17, and the surface of the belt 6 is detected. When the temperature reaches a predetermined temperature, the toner image is transferred from the intermediate transfer body 22 to the recording medium.

The recording medium 7 onto which the image has been transferred is transferred onto the belt 6 of the fixing belt device 3 by a conveying mechanism (not shown), the toner image on the recording medium 7 is melted by the heating roller 2, and is applied by the pressure roller 4. The fixing is completed by being pressed and passing through the nip region between the heating roller 2 and the belt 6, and the recording medium 7 on which the fixing is completed is carried out by a conveyance mechanism (not shown).
It is conveyed in the direction of the upward arrow and placed on top of the image forming apparatus 1.

On the other hand, when a jam of the recording medium 7 occurs on the upstream side of the heating roller 2, the operator pulls the grip 19 and rotates the open / close door 12 in the counterclockwise direction in FIG. This door 1
By opening 2, the power source of the image forming apparatus is cut off, the rotation of the pressure roller 4 and the heating roller 2 is stopped, and the heat generation of the heating roller 2 is stopped.

The cleaning means 16 and the temperature detecting means 17 are moved leftward by the opening operation of the opening / closing door 12.
Further, the cam 11 at the lower part of the opening / closing door 12 rotates counterclockwise around the shaft core 12a, and the side surface 11a thereof has the operating plate 1
It abuts the 0 roller 13.

Further rotation of the opening / closing door 12 causes the operating plate 10 to rotate clockwise about the shaft core 10b. The pin 10a implanted in the operating plate 10 is a long hole 8d in the mounting plate 8.
Since it is slidably fitted to the mounting plate 8, the mounting plate 8 rotates counterclockwise about the shaft core 8a, the pressure roller 4 is separated from the heating roller 2, and the tension roller 9 is The belt 6 is rotated in a direction to loosen the tension.

Then, when the opening / closing door 12 is rotated by 90 °, the operating plate 10 and the mounting plate 8 are indicated by imaginary lines 1 respectively.
When the positions 0'and 8'are reached, the fixing belt device 3 is completely detached from the heating roller 2. By opening the opening / closing door 12, the space between the heating roller 2 and the belt 6 can be observed from the outside, and the recording medium jammed by the operator's hand or tweezers can be easily removed.

In this embodiment, the rotating shaft 4a of the pressure roller 4 is pressed against the heating roller 2 side by the spring 15, but the present invention is not limited to this.
Heating roller 2 and belt 6, pressure roller 4, and spring 14
By appropriately setting the biasing force of the
It is not necessary to adjust the position of the pressure roller 4 by b.
It can be operated only by the spring 15 and the stopper 23 in that case.
Of course, it is not necessary to use.

Further, in the present embodiment, cleaning means for pressing the surface of the fixing belt to clean the surface of the fixing belt, and temperature detecting means for contacting the surface of the fixing belt to detect the surface temperature are extended from the opening / closing door. Although it is disposed on the existing arm portion 18, the arm portion 18 may be configured separately from the opening / closing door 12 so that both means can be brought into contact with / separated from the belt 6 by opening / closing the opening / closing door 12. Good.

As described above in detail, in the present embodiment, the opening / closing door 12 is disposed on the side surface of the frame 10 of the image forming apparatus so as to be openable / closable, and the fixing belt device 3 is on the opening / closing door side. Since the recording medium after fixing is arranged so as to be ejected, it is possible to observe the space between the heating roller 2 and the belt 6 from the outside by opening the opening / closing door 12, and the jammed recording medium can be easily removed. Can be eliminated.

Further, in the present embodiment, the mounting plate on which the pressure roller and the tension roller are arranged is rotatably arranged around the axis, and the rotation shafts of the pressure roller and the tension roller are Since the springs 14 are arranged at positions urged in opposite directions by the urging force of the springs 14 about the axis of the mounting plate, the pressing force of the belt 6 toward the heating roller 2 by one spring 14, The pressing on the tension roller 9 can be shared.

Further, the present embodiment is provided with a cleaning means for pressing the surface of the fixing belt to clean the surface of the fixing belt, and a temperature detecting means for contacting with the surface of the belt to detect the surface temperature. Since the means is configured to move from the belt surface to the outside of the separation movement area of the fixing belt device in conjunction with the opening operation of the opening / closing door, a separation space is provided between the fixing belt device 3 and the heating roller 2. Since the both means have already been moved to the outside of the separating movement area of the fixing belt device when forming the sheet, they do not collide with the moving fixing belt device.

Further, in this embodiment, since the power switch of the image forming apparatus is arranged in the opening / closing operation range of the opening / closing door,
The power is automatically turned off by the opening operation of the opening / closing door, there is no need for other special operation, the power is not continuously applied to the drive member, the fear of electric shock is eliminated, and it is reflected by the shock of electric shock. The operator's hand does not touch the high temperature part and burns the high temperature part, and the high temperature of the heating roller cools down naturally after a lapse of an appropriate time after the power is turned off, and the recording medium is safely jammed. Can be taken out.

[0041]

As described above in detail, the present invention can provide a belt fixing device having a simple structure and capable of easily removing a jammed recording medium.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a belt fixing device in an image forming apparatus used in the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of an image forming apparatus.

FIG. 3 is a view on arrow AA of FIG.

FIG. 4 is a configuration diagram showing a conventional example.

[Explanation of symbols]

1: Image forming apparatus 2: Heating roller 3: Fixing belt device 4: Pressure roller 5: Driven roller 6: Belt 7: Recording medium 8: Mounting plate 9: Tension roller 11: Cam 12: Door 16: Cleaning means 17: Temperature measuring means 19: Handle 20: Power switch 22: Transfer body

Continuation of the front page (56) Reference JP-A-5-181329 (JP, A) JP-A-5-127559 (JP, A) JP-A-4-245276 (JP, A) Actually open 4-37961 (JP , U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (3)

(57) [Claims] 1. A recording medium on which toner is superposed between a fixing belt wound by a plurality of rollers and a heating roller is allowed to pass through, and the fixing belt is operable to be separated in the radial direction of the heating roller. In the belt fixing device, a tension roller for applying tension to the belt is provided in the loop of the fixing belt, a mounting plate is rotatably arranged in association with a separation operation of the fixing belt, and the tension roller, A pressure roller that presses the fixing belt in the radial direction of the heating roller is rotatably attached to the mounting plate, and the rotation shafts of the pressure roller and the tension roller are the rotation axis cores of the mounting plate. Located on opposite sides of the
The plate is urged around its axis of rotation so that the pressure roller and
And the rotation shaft of the tension roller is the rotation shaft of the mounting plate.
A belt fixing device characterized in that the cores are urged in directions opposite to each other . 2. A cleaning means for pressing the surface of the fixing belt to clean the surface of the fixing belt, and a temperature detecting means for detecting the surface temperature of the surface of the fixing belt. 2. The belt fixing device according to claim 1, wherein the belt fixing device moves from the surface of the belt to a position outside the separating movement range of the fixing belt device during the separating operation in association with the opening operation of the opening / closing door disposed on the side surface of the fixing belt device. 3. A power switch of the image forming apparatus is arranged in an opening / closing operation area of an opening / closing door arranged on a side surface of the image forming apparatus,
The belt fixing device according to claim 2, wherein the power source is cut off by opening the opening / closing door.