JPH0675497A - Fixing device - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to extend the life without generating offset and surface defects. A surface of a heating roller 1 in a fixing device that includes a heating roller 1 having a built-in heater 2 and a pressure roller 3 that is in pressure contact with the heating roller 1 and inserts a transfer material 5 between the rollers to perform fixing. Is provided with a pressing member 9 for cleaning
The pressing member 9 is connected to the heating roller 1 by a solenoid 15
Is used as a drive source, the pressing member 9 is pressed and retracted by the heating roller 1 via the lever 12, and the pressing member 9 is brought into contact with the heating roller 1 only when necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device, and more particularly to a fixing device.
The present invention relates to a fixing device used in an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art FIG. 4 is a front view showing a conventional fixing device.

The fixing device shown here is of an oilless type and has a built-in heater 2 and a rotatable heating roller 1.
And a pair of rollers composed of a pressure roller 3 which is pressed against the lower part of the roller and rotates.
The transfer material 5 (carried in from the transfer section side) to which (a toner image which is the same as or similar to the original image) is attached is passed.

In the process of passing between the rollers, the toner 4 on the transfer material 5 is welded and fixed by pressure and heat, and the transfer paper material 5 on which the fixing is completed is discharged to a discharge tray (not shown) via a conveying means (not shown). ) Is sent to. Normally, the transfer material 5 is conveyed on a flat surface, but sometimes it may wind around the surface of the roller 1. In order to prevent this, the separation claw 6 is in contact with the surface of the heating roller 1 so that the transfer material 5 that has started to wind can be separated.

On the surface of the heating roller 1, a temperature controller 7 including a thermistor as a temperature sensor is attached to the heating roller 1, and the surface temperature of the heating roller 1 is controlled to be kept within a desired temperature range. .

FIG. 5 is a front view showing another example of a conventional fixing device. In FIG. 5, the same reference numerals are used for the same elements as those in FIG. 4, and thus duplicated description will be omitted.

In the fixing device shown here, in addition to the structure shown in FIG. 4, a cleaning roller 8 is provided in contact with the heating roller 1. By providing the cleaning roller 8, even if a part of the toner 4 adheres to the heating roller 1, it is removed from the surface of the heating roller 1 and does not adhere to the next transfer material to cause stains.

[0008]

However, in the above-mentioned prior art, if the transfer material is continuously fed for a long time, the surface of the heating roller becomes rough due to the abrasion of the resin and the filler, and finally the heating roller is formed. Polishing flaws on the surface appear on the surface,
Toner penetrates into these flaws and accumulates and grows, eventually causing the toner to cause offset.

Therefore, as disclosed in Japanese Patent Laid-Open No. 63-311287, a method has been proposed in which the heating roller is reheated and then the resin is melted so that the polishing flaws are filled. Although the life of the heating roller up to the offset is slightly extended as compared with the case where the heating roller is not heated, the surface of the heating roller due to the transfer material is abraded and the surface is roughened as a result of long-term use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device which is free from offset and surface flaws and has a long service life.

[0011]

In order to achieve the above object, the present invention comprises a heating roller having a built-in heat source and a pressure roller in pressure contact with the heating roller, and a transfer material is provided between the rollers. In the fixing device that inserts and fixes
A pressing member for cleaning the surface of the heating roller and a driving unit for pressing and retracting the pressing member against the heating roller are provided.

Further, the above object is to provide a pressing member for cleaning the surface of the heating roller, and a driving means for reciprocating the pressing member in the longitudinal direction of the heating roller and positioning it outside the paper passing area when no paper is passing. It is also achieved by providing.

[0013]

According to the above-mentioned means, the pressing member comes into contact with the surface of the heating roller only when necessary or intervenes in the paper passing area, and is retracted from the surface of the heating roller or the paper passing area when unnecessary. Therefore, it is possible to reduce the surface roughness of the heating roller, extend the life of the heating roller, and prevent image deterioration.

[0014]

1 is a perspective view showing an embodiment of a fixing device according to the present invention. Note that, in FIG. 1, the same reference numerals are used for the same components as those shown in FIG.

This embodiment is characterized in that a pressing member 9 is provided instead of the cleaning roller 8 shown in FIG. As shown in FIG. 2, the pressing member 9 has a roughness of 10 μm on the surface.
A resin body 10 made of a heat-resistant resin such as a fluororesin or a polyimide resin having a size of m or less, and a silicon sponge, a fluororesin sponge, or the like (the hardness thereof is 6 in Asker C hardness) is used.
It is preferably 0 degrees or less) and a holding metal fitting 11 for holding the resin body 10.

The pressing member 9 is, as shown in FIG.
One end of the "L" -shaped lever 12 is fixed to the holding metal fitting 11, and a fulcrum 13 is provided at the "L" -shaped bent portion, and the fulcrum 13 can be rotated about the fulcrum 13. Lever 12
One end of the spring 14 is connected to the other end (upper end) of
The lever 12 is biased clockwise in the drawing. further,
An armature of a solenoid 15 is connected to the upper end of the lever 12, and the lever 12 can be rotated counterclockwise against the biasing force of the spring 14.

In the configuration of FIG. 1, when the fixing device starts up (starts up), the solenoid 15 is turned on by a signal from the main body of the apparatus, and the resin member 1 of the pressing member 9 is turned on.
0 is pressed against the surface of the heating roller 1. Then, when a print button (not shown) provided on the operation panel of the image forming apparatus is pressed, the solenoid 15 is turned off and the pressing member 9 is separated from the heating roller 1.

As described above, in this embodiment, since the pressing member 9 comes into contact with the heating roller 1 only at the start of starting, the wear of the surface layer portion of the heating roller 1 is extremely small even during long-term use, and an offset is generated. Disappears.

FIG. 3 is a schematic block diagram showing another embodiment of the present invention. In the present embodiment, the same reference numerals are used for the same components as those shown in FIG. 1, and thus duplicated description will be omitted here.

The present embodiment is the same up to the point where the pressing member 9 is used, but the pressing member 9 ', which is a shortened pressing member 9, is replaced with contact / non-contact operation with respect to the heating roller 1, and pressing is performed when not in use. The feature is that the member 9'is retracted to the outside of the paper-passing area.

That is, a pair of pulleys 16 and 17 are arranged at both ends of the heating roller 1, and a wire 18 is provided between the pulleys.
And a pressing member 9'is engaged in the middle.
The rotary shaft of the pulse motor 19 is directly connected to the rotary shaft of the pulley 16. Further, in order to detect that the pressing member 9'is at the home position outside the sheet passing area, the sensor 2
0 is provided.

In this embodiment, the pressing member 9'can be moved left and right by driving the pulse motor 19 controlled by a CPU (not shown). First, the CPU issues a command to move the pulse motor 19 to the X step (= B position). When the pressing member 9 ′ reaches the X step, the CPU issues a command to rotate the pulse motor 19 in the reverse direction, and moves the pressing member 9 ′ to the position A (home position) shown in the figure.

The arrival of the pressing member 9'at the position A is detected by the sensor 2
Detected by 0, the signal is immediately sent to the CPU. In response to this, the CPU controls the driving of the pulse motor 19 to stop, and stops the pulse motor 19. In this way, the pressing member 9'cleans the paper passing area only when the apparatus is started, and normally stands by at the home position outside the paper passing area. Therefore, the wear of the surface layer of the heating roller 1 is extremely small, and the offset does not occur.

[0024]

Since the present invention is configured as described above, it has the following effects.

In the fixing device according to the first aspect of the present invention, there is provided a heating roller having a built-in heat source and a pressure roller which is in pressure contact with the heating roller, and a transfer material is inserted between the rollers to perform fixing. Since the pressing member for cleaning the surface of the heating roller and the driving means for pressing and retracting the pressing member with respect to the heating roller are provided, the pressing member is retracted from the heating roller during paper passing. Therefore, it is possible to prevent banding of an image due to an increase in torque due to the pressing of the pressing member, and to reduce the abrasion of the surface of the heating roller.

In the fixing device according to the second aspect of the present invention, there is provided a heating roller having a built-in heat source and a pressure roller in pressure contact with the heating roller, and a transfer material is inserted between the rollers to perform fixing. Since the pressing member for cleaning the surface of the heating roller and the driving means for reciprocating the pressing member in the longitudinal direction of the heating roller and for positioning the heating roller outside the paper passing area when the paper is not passed, the offset is provided. The roller surface is not damaged and the life can be extended.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a fixing device according to the present invention.

FIG. 2 is a perspective view showing a detailed configuration of a pressing member according to the present invention.

FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 4 is a front view showing a conventional fixing device.

FIG. 5 is a front view showing another example of a conventional fixing device.

[Explanation of symbols]

 1 Heating Roller 2 Heater 3 Pressure Roller 6 Separation Claw 7 Temperature Controller 9, 9'Pressing Member 10 Resin Body 11 Holding Metal 12 Lever 13 Support Point 14 Spring 15 Solenoid 16, 17 Pulley 18 Wire 19 Pulse Motor 20 Sensor

Claims (2)

[Claims] 1. A fixing device, comprising: a heating roller having a built-in heat source; and a pressure roller that comes into pressure contact with the heating roller, wherein a transfer material is inserted between the rollers to fix the surface of the heating roller. A fixing device comprising: a pressing member to be cleaned; and a driving unit that presses the pressing member against the heating roller and retracts it. 2. A fixing device comprising a heating roller having a built-in heat source and a pressure roller in pressure contact with the heating roller, wherein a transfer material is inserted between the rollers to fix the surface of the heating roller. 2. A fixing device comprising: a pressing member to be cleaned; and a driving unit that reciprocates the pressing member in the longitudinal direction of the heating roller and positions it outside the paper passing area when no paper is passing.