JPH0792843A - Fixing device - Google Patents

Abstract

PURPOSE:To steadily carry out cleaning and to maintain a satisfactory fixing operation, in a fixing device provided with a cleaning means impregnated or coated with an offset prevention liquid. CONSTITUTION:An endless cleaning belt 17 composed of a heat-resistant member is provided in contact with the surface of the heat roller 4 of a fixing means, which consists of the heat roller 4 for carrying paper P with an image of toner T thereon under the application of heat and a pressure roller 5 for carrying the paper while pressing the image carrier to the heat roller 4. The cleaning belt 17 is slid in synchronization with the rotation of the heat roller 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, an electrostatic copying machine,
A fixing device applied to an electrophotographic image forming apparatus such as a laser printer or an electrophotographic facsimile, and more specifically, a heating roller for welding a powder image to a transfer member,
The present invention relates to a fixing device including a pressure roller for pressing the transfer member against the heating roller.

[0002]

2. Description of the Related Art In recent years, a heating roller type fixing device has been widely used in an electrophotographic image forming apparatus because it has a feature of being capable of stable fixing while having a small size.

This heating roller type fixing device is provided with a heating roller (fuser roller) and a pressure roller (press roller) which is in pressure contact with the heating roller, and a transfer member such as paper is passed between these rollers to transfer the toner. The powder image (toner image) on the member is heated and fused and fixed.

Conventionally, in this type of fixing device, a cleaning member impregnated with an offset preventing liquid is pressed against the surface of the heating roller with a constant pressing force as a mechanism for preventing the toner offset to the heating roller and cleaning. While continuously supplying means (Actual development 50-110245),
A method has been disclosed in which the cleaning member fed by the feeding unit is pressed against the fixing roller by the coating roller of the peeling liquid coating unit (Actual No. 59-73760).

[0005]

However, according to the conventional method, when the cleaning member composed of the endless belt impregnated or coated with the offset preventing liquid is continuously supplied by the feeding means, the cleaning member extends. Or, since the offset prevention liquid is applied, slippage occurs with the feeding means, and the driving force of the feeding means cannot be reliably transmitted to the cleaning member. Further, in order to solve this problem, when the cleaning member is wound up, if the cleaning member is made to have a long life, a long cleaning member is required, which causes an increase in size of the apparatus.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to perform stable cleaning in a fixing device provided with a cleaning means impregnated with or applied with an offset prevention liquid and to perform a good fixing operation. It is to provide a fixing device capable of maintaining the above.

[0007]

As a means for solving the above problems, the present invention provides a heating roller that heats and conveys an image bearing member carrying a developer image, and the above-mentioned image with respect to the heating roller. A fixing unit composed of a pressure roller that conveys the carrier while pressing it, a driving unit that drives a roller pair of the fixing unit, and a member that is in contact with the heating roller surface of the fixing unit and has heat resistance. And an endless belt member, and a sliding unit for sliding the belt member against the heating roller of the fixing unit in synchronization with the driving unit driving the fixing unit. It is what

[0008]

According to the fixing device of the present invention, the cleaning member composed of the endless belt impregnated or coated with the offset prevention liquid is configured to contact the surface of the heating roller, and the cleaning member composed of the endless belt is provided. By sliding on the heating roller, the offset preventing liquid can be efficiently supplied to the heating roller and the cleaning efficiency can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows the configuration of the fixing device 1. The fixing device 1 is located on the upper surface side of the paper transport path 2 and has a heating roller (fuser roller) 4 having a heater lamp 3 as a heat source therein, and the paper transport device. A fixing of a heating roller type as a fixing unit including a pressure roller (press roller) 5 located on the lower surface side of the path 2 and pressed against the heating roller 4 by an urging force of an urging mechanism (not shown). It is a device.

By passing the sheet P as an image carrier between the heating roller 4 and the pressure roller 5, the toner T forming the powder image on the sheet P is fused and fixed. There is.

The heating roller 4 and the pressure roller 5 are surrounded by an upper casing 6 and a lower casing 7, and have a structure in which heat does not escape to the outside as much as possible so as to secure a favorable temperature atmosphere necessary for fixing. Has become. Further, a fuser guard (not shown) is provided on the upper surface side of the upper casing 6 so as to cover the upper casing 6 as a safety means for preventing burns.

Further, inlet guides 8 and 9 are provided in the vicinity of the upstream side of the contact portion between the heating roller 4 and the pressure roller 5, that is, at the inlet side of the fixing device 1, and powders of toner T are used. The leading end of the sheet P on which the image is formed is reliably guided between the heating roller 4 and the pressure roller 5.

Further, in the vicinity of the downstream side of the contact portion between the heating roller 4 and the pressure roller 5, that is, at the exit side of the fixing device 1, the peeling for peeling the paper P wound around the heating roller 4 and the pressure roller 5 is performed. The claws 10 and 11 are provided, and the exit guide 12 is provided so as to guide the fixed paper P to a paper discharge device (not shown).

The heating roller 4 is maintained at a certain temperature while being controlled in temperature by the thermistor 15. In this embodiment, the surface temperature of the heating roller 4 is controlled to 190 ± 5 ° C.

Further, on the upper surface side of the heating roller 4, a cleaning mechanism 16 as a cleaning means for cleaning the surface of the heating roller 4 while applying the offset prevention liquid thereto.
Is provided.

The cleaning mechanism 16 is provided so as to be in contact with the surface of the heating roller 4, and is a cleaning member (hereinafter referred to as a cleaning belt) 1 which is an endless belt impregnated or coated with an offset preventing liquid.
7 and a belt conveyance mechanism 18 as a sliding means for feeding the cleaning belt 17.

Further, as shown in FIG. 2, the cleaning belt 17 has an offset prevention liquid coating member 20 as a first layer, a heat resistant adhesive layer 21 as a third layer, and a drive as a second layer. It has a three-layer structure with the force transmission member 22.

The offset prevention liquid application member 20 located on the side in contact with the surface of the heating roller 4 (outer side of the belt) holds the offset prevention liquid and is a material which does not easily wear the surface of the heating roller 4, for example, heat resistance. Composed of felt.

Further, the drive roller 2 of the belt transport mechanism 18
The driving force transmission member 22 located on the side in contact with 3 (inner side of the belt) is made of a material that has excellent driving force transmission force, good heat resistance, and can be processed into a belt shape, such as silicon rubber or fluororubber.

A heat-resistant adhesive layer 21 provided between the offset prevention liquid coating member 20 and the driving force transmission member 22.
Is composed of a silicone rubber-based heat-resistant adhesive or the like. Further, the offset prevention liquid application member 20 is previously impregnated with the offset application liquid.

As shown in FIG. 1, the belt transport mechanism 18 keeps the cleaning belt 17 in a fixed direction (direction of arrow a).
Drive roller 23 for feeding to and cleaning belt 1
A pair of pressing rollers 2 for pressing the heating roller 7 against the heating roller 4.
5, 25, an idle roller 26, and a tension roller 27 for preventing the cleaning belt 17 from bending during feeding.

The pressing rollers 25, 25 have a heat resistance of 230 ° C. or more and a low hardness (Asker C 55 degrees or less) so that the cleaning belt 17 is brought into close contact with the heating roller 4 and the feeding of the cleaning belt 17 is not hindered. Silicon rubber or heat-resistant foamed silicone rubber roller was used.

Next, the drive force transmission mechanism 30 as a drive means for transmitting the drive force to the drive roller 23 will be described with reference to FIG. A belt drive gear 23A is attached to one end side of the drive roller 23, and the belt drive gear 2
3A interlocks with a heating roller gear 4A provided on one end side of the heating roller 4 via an idle gear 31.

The heating roller gear 4A is used for the fixing device 1.
When it is incorporated into the image forming apparatus, the drive gear 32 in the image forming apparatus is engaged with the drive gear 32 to receive the driving force. The drive ratio was set to 1/10.

The heating roller gear 4A is a pressure roller gear (not shown) provided on one end side of the pressure roller 5.
The heating roller 4 rotates in the clockwise direction (direction of arrow b) in FIG. 1 and the pressure roller 5 rotates in the width direction (direction of arrow c) with respect to the heating roller 4. ing. The drive roller 23 integrated with the belt drive gear 23A that interlocks with the heating roller gear 4A via the idle gear 31 is configured to rotate in the clockwise direction (direction of arrow d) in FIG.

The tension roller 27 is adapted to apply a certain constant pressure to the cleaning belt 17 by a spring (not shown). The fixing device 1 according to the present exemplary embodiment is 4
When a paper threading test (printing rate 5%) was carried out by adopting an electrophotographic copying machine of 0 sheet (A4), good image quality was obtained even with 100,000 sheet A4 continuous copying.

4 and 5 show the cleaning belt 1.
7 shows different embodiments of the present invention, the cleaning belt 17 is not only impregnated with the offset preventing liquid, but also pushed in order to supply the offset preventing liquid to the heating roller 4 in a larger amount or over a long life. This roller 25,
25 is also impregnated with the offset prevention liquid.

FIG. 4 shows the pressing rollers 25, 25.
More offset prevention liquid is applied to the offset prevention liquid coating member 20.
Driving force transmitting members 22 are provided only at both ends. In other words, it is provided outside the pressing roller 25 and entirely or partially inside the drive roller 23.

As described above, the offset preventing liquid can be supplied to the heating roller 4 for a long time, and more stable fixing operation becomes possible. Further, in the structure shown in FIG. 5, foaming (continuous foaming) silicone rubber may be used for the driving force transmitting member 22 and the heat resistant adhesive layers 21 may be provided only on both ends as in the case of FIG.

As a method of driving the drive roller 23, in addition to the method shown in FIG. 3, a drive device for the drive roller 23 is provided to intermittently feed the cleaning belt 17, or a dedicated drive device is provided. Instead of the heating roller 4 and the pressing rollers 25, the cleaning belt 17 may be driven by the heating roller 4 and driven.

Further, as shown in FIG. 6, the cleaning belt 17 is separated from the heating roller 4 so that a gap G is formed between the cleaning belt 17 and the heating roller 4 when the fixing operation is stopped. Excessive application of the offset prevention liquid to the heating roller 4 when the fixing operation is stopped may be prevented. As a result, it is possible to prevent the adverse effect such as the adhesion of the offset prevention liquid on the paper P.

Next, with reference to FIGS. 7 and 8, a specific structure of the contact / separation mechanism 33 for separating the cleaning belt 17 from the heating roller 4 will be described. The tension roller 27 is attached to an upper end portion of a lever 36 whose lower end portion is connected to a plunger 35a of a solenoid 35, and the pressing rollers 25, 25 have one end at an intermediate portion of the lever 36 via a shaft 37. Mounted rotatable arms 38,3
It is attached to 8. These arms 38, 38 include
One ends of the tension springs 39, 39 serving as biasing means are connected to each other and are constantly biased downward. Further, the stopper pins 40, 4 are provided on the lower end surface side of the arms 38, 38.
0 is fixedly arranged.

During the fixing operation, the solenoid 35 is turned off.
In this state, the arms 38, 38 to which the pressing rollers 25, 25 are attached are brought into contact with the stopper pins 40, 40 by the urging force of the tension springs 39, 39. Then, as shown in FIG. 7, the cleaning belt 17 is pressed against the heating roller 4 by the pressing rollers 25, 25.

On the other hand, the lever 36 is raised, and the tension roller 27 attached to the upper end of the lever 36 pushes down the cleaning belt 17 by the urging force of the spring 41.
Tension is applied to the cleaning belt 17.

When the fixing operation is stopped, the solenoid 35 is turned on.
By setting the lever to the N state, the lever 36 is moved to the tension spring 39, 39
It is lowered against the urging force of. As a result, as shown in FIG. 8, the arm 3 to which the pressing rollers 25, 25 are attached
8 and 38 are lifted with the stopper pins 40 and 40 as fulcrums, and the tension roller 27 descends to push the cleaning belt 17 and apply tension to the cleaning belt 17.

As a result, the cleaning belt 17 is separated from the heating roller 4. In addition, this FIG.
In the description of FIGS. 8 to 8, the same parts as those in the above-described embodiment (FIG. 1) are designated by the same reference numerals and detailed description thereof will be omitted.
In addition, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0037]

As described above, according to the present invention,
In the fixing device provided with the cleaning means impregnated or applied with the offset prevention liquid, stable cleaning can be performed, and good fixing operation can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a fixing device of the present invention.

FIG. 2 is a schematic cross-sectional view showing a structure of a cleaning belt which is a main part of the same.

FIG. 3 is a schematic view showing a driving force transmission mechanism that transmits a driving force to a belt driving roller.

FIG. 4 is a diagram showing a first other embodiment of a cleaning belt, which is a main part.

FIG. 5 is a view showing a second other embodiment of the cleaning belt, which is a main part.

FIG. 6 is a schematic configuration diagram showing another embodiment of the fixing device of the present invention.

FIG. 7 is a schematic view showing a state of a contacting / separating mechanism, which is a main part, during a fixing operation.

FIG. 8 is a schematic view showing a state when the fixing operation of the contact / separation mechanism, which is a main part, is stopped.

[Description of Reference Signs] 1 ... Fixing device, 2 ... Paper transport path, 3 ... Heater lamp (heat source), 4 ... Heating roller, 5 ... Pressure roller, 16 ... Cleaning mechanism (cleaning means), 17 ... Cleaning belt (cleaning) Member), 18 ... Belt transport mechanism (sliding means), 20 ... Offset prevention liquid application member (first
, 21 ... Heat-resistant adhesive layer, 22 ... Driving force transmitting member (second layer), 23 ... Driving roller, 25 ... Pushing roller, 26
... Idle roller, 27 ... Tension roller, 30 ... Driving force transmission mechanism (driving means), 33 ... Contact / separation mechanism, 35 ... Solenoid, 35a ... Plunger, 36 ... Lever, 37
... shaft, 38 ... arm, 39 ... tension spring (biasing means), 4
0 ... Stopper pin, 41 ... Spring, P ... Paper (image carrier), T ... Toner.

Claims (4)

[Claims] 1. A fixing unit comprising a heating roller for heating and carrying an image bearing member carrying a developer image, and a pressure roller for carrying the image bearing member while pressing the image bearing member against the heating roller. A driving means for driving the roller pair of the fixing means; an endless belt member made of a heat-resistant member in contact with the heating roller surface of the fixing means; and the driving means for driving the belt member. A fixing device comprising: a sliding unit that slides in synchronization with the heating roller of the fixing unit by driving the fixing unit. 2. A fixing unit comprising a heating roller for heating and transporting an image bearing member carrying a developer image, and a pressure roller for transporting while pressing the image bearing member against the heating roller. An endless end formed of a first layer containing an anti-offset liquid and a second layer made of a heat-resistant elastic body, the first layer being in contact with the heating roller of the fixing means. A cleaning unit including a belt member; a supporting unit for supporting the cleaning unit by contacting the second layer of the cleaning unit; and a cleaning unit supported by the supporting unit for driving the cleaning unit. The first
And a supply unit configured to supply the offset prevention liquid impregnated in the layer to the heating roller surface of the fixing unit. 3. A fixing means comprising a heating roller for heating and carrying an image bearing member carrying a developer image, and a pressure roller for feeding while carrying the image bearing member against the heating roller. Driving means for driving the roller pair of the fixing means, and contacting the heating roller surface of the fixing means when the fixing means is driven by the driving means, and the fixing means when the fixing means is stopped. An endless belt member spaced from the heating roller surface of the fixing roller, and a sliding means for sliding the belt member with respect to the heating roller of the fixing means when the belt member is in contact with the heating roller surface of the fixing means, A fixing device comprising: 4. A fixing means comprising a heating roller for heating and carrying an image bearing member carrying a developer image, and a pressure roller for carrying the developer bearing image while pressing the image bearing member against the heating roller. An endless belt member that is in contact with the surface of the heating roller of the fixing unit; a supporting unit that winds the belt member and supports the belt member; and the belt member supported by the supporting unit. And a tensioning means for tensioning the belt member with a predetermined force.