JP2000098789A - Fixing device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress frictional force between a cleaning member and a rotary body for fixing by simple constitution, to prevent a gear and the like from being damaged and to prolong a service life by moving a contact surface between the surface of the rotary body for fixing and the cleaning member when the rotary body for fixing is stopped. SOLUTION: Just before a next recording material is carried to a fixing nip part after the fixing of the recording material P is finished, that means, between the recording materials, the rotation of a fixing roller 51 and a pressure roller 52 is stopped. In this stopped state, the cleaning webs 54a and 55a are taken up. Thus, since the frictional force between both rollers 51 and 52 and the webs 54a and 55a is reduced, the webs 54a and 55a can be stably fed. That means, the take-up amount of the webs can be stably obtained. Besides, since that the webs 54a and 55a are taken up while being separated from both roller 51 and 52 is eliminated, toner is prevented from dropping down from the webs 54a and 55a. Thus, an image defect is not caused and members arranged at more downstream side than the webs 54a and 55a are not soiled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer, and a fixing device used in the image forming apparatus.

[0002]

2. Description of the Related Art Various types of image forming apparatuses are known. Among them, an electrophotographic image forming apparatus that performs image exposure on a photoreceptor with a laser beam and develops the image to obtain an image is widely used. I have. Such an image forming apparatus has advantages such as high image quality and high speed, and is widely used as an output device such as a copying machine and a color laser beam printer.

[0003] These image forming apparatuses are provided with a fixing device for fixing the toner image formed on the transfer material as a permanent image.

FIG. 9 shows an example of a conventional fixing device 180. The fixing device 180 includes a fixing roller 151, which is rotatably disposed as a fixing rotator, and a pressure roller 152, which rotates while pressing against the fixing roller 151.
And a release agent application device 153 for applying a release agent to the fixing roller 151, and a cleaning device 154 for removing toner and paper dust attached to the fixing roller 151.

Fixing roller 151 and pressure roller 152
Inside heaters 156 and 157 such as halogen lamps.
Are arranged respectively. The fixing roller 151 and the pressure roller 152 have a thermistor 158, respectively.
159 are arranged so as to be in contact with each other, and the temperature of the surfaces of the fixing roller 151 and the pressure roller 152 is controlled by controlling the voltage to the heaters 156 and 157 via a temperature control circuit.

The fixing roller 151 cleans toner and the like offset on the fixing roller 151 by a cleaning device 154, and releases silicone oil or the like as a release agent to the fixing roller 151 by a release agent application device 153. It is applied to facilitate the separation of the transfer paper P from the fixing roller 151 and to prevent toner offset.

The release agent applying device 153 applies pumping rollers 153b and 153c for pumping silicone oil from an oil tank 153a for storing silicone oil, and an applying roller 153d for applying silicone oil from the pumping rollers 153b and 153c to the fixing roller 151.
And a blade 153e for controlling the amount of oil applied from the application roller 153d. In particular, the release agent applying device 153 fixes the thermistor 158 to the thermistor 158 so as to evenly apply the oil to the fixing roller 151. It is arranged downstream of the roller 51 in the rotation direction.

The application roller 153d is a rotatable roller in which sponge rubber is coated with silicone rubber on its surface. The roller is in contact with the fixing roller 151 if necessary, and applies silicone oil to the fixing roller 151. .

The cleaning device 154 is a cleaning web 154a, which is a cleaning member made of a heat-resistant non-woven band.
, A pressing roller 154 b for pressing the cleaning web 154 a against the fixing roller 151, an unwinding roller 154 c for unwinding a new cleaning web 154 a, and a cleaning web 154 a having a reduced cleaning ability due to adhesion of toner and the like, are gradually wound up. It is composed of a take-up roller 154d and the like.
The cleaning device 154 is provided upstream of the thermistor 158 in the rotation direction of the fixing roller 151 so that the offset toner offset to 8 does not adhere to the thermistor 158 to cause a detection failure.

As a method of winding the cleaning web 154a, when a counter counts a predetermined number of copies, a web solenoid (not shown) is turned on and a one-way clutch is operated, so that the cleaning web 154a is rotated in a direction opposite to the roller rotation direction. It has been wound up by a predetermined amount. By taking up in the opposite direction, the cleaning web 154a is prevented from being taken up in the roller rotation direction.

Further, the fixing roller 1 is
A cleaning device including a cleaning web, a pressing roller, an unwinding roller, a winding roller and the like similar to the cleaning device 154 of FIG.
The toner adhered to the pressure roller 152 via the cleaning roller 51 may be cleaned.

An oil removing blade 160 for removing excess release material remaining on the pressure roller 152 is in contact with the pressure roller 152. This oil removal blade 1
If there is no 60, the excess release agent accumulates in the nip between the fixing roller 151 and the pressure roller 152, causing stains on the recording material, and the transparent laminating film for OHP slipping into the nip. Failure occurs. The oil removing blade 160 is in contact with the rotating direction of the pressure roller 152 in a forward or reverse direction with an appropriate amount of approach.

In the above configuration, when the transfer material P is conveyed, the fixing roller 151 and the pressure roller 152 rotate, silicone oil is applied as a release agent to the surface of the fixing roller 151, and the transfer material P is fixed. When the paper passes between the roller 151 and the pressure roller 152, pressure and temperature are applied from both the front and back surfaces at a substantially constant pressure and temperature, and the unfixed image on the surface of the transfer material is melted and fixed. A fixed image is formed. The transfer material P on which the image has been fixed is separated from the pressure roller 152 by the lower separation claw 168, and is discharged out of the apparatus.

[0014]

A cleaning web (hereinafter simply referred to as "web") for cleaning the surface of the fixing roller has conventionally been wound in a direction opposite to the rotation direction of the fixing roller. By doing so, the web is fed only in the direction opposite to the rotation direction of the fixing roller, so that the web is prevented from being caught in the rotation direction of the fixing roller.

However, since the web is fed in the direction opposite to the rotation direction of the fixing roller, when the web is wound while the fixing roller is rotating, the frictional force between the fixing roller and the web is large, and therefore the driving system is Short life has occurred due to breakage of the interposed gear.

Further, in a model in which the amount of the release agent applied on the surface of the fixing roller is small, the frictional force between the fixing roller and the web is further increased. Sometimes, the winding amount became unstable. For this reason, when the web feed amount is smaller than the set value, a large amount of toner adheres to the web surface, and the cleaning power is insufficient, which causes a problem such that an image defect occurs and the adhered toner damages the fixing roller. there were.

Specifically, when the surface layer material of the fixing roller is silicone rubber and the amount of the release agent applied is 20 mg / A4 or less, this phenomenon has become remarkable.

In order to prevent this, there is a web attaching / detaching mechanism which allows the web and the fixing roller to be able to contact and separate from each other, and there is an apparatus which winds up the web when the web is separated from the fixing roller, but the structure becomes complicated. However, there were problems in terms of space and cost. In this case, toner and paper dust accumulated between the web and the fixing roller when the web separates from the fixing roller remain on the fixing roller and adhere to a member located downstream in the rotation direction to cause roller damage. Or an image defect occurs.

Accordingly, a main object of the present invention is to provide a fixing device capable of achieving a long life by suppressing the frictional force between the cleaning member and the fixing rotating member with a simple structure, and an image provided with the fixing device. It is to provide a forming device.

Another object of the present invention is to provide a fixing device capable of stably obtaining a winding amount of a cleaning member with a simple structure, and an image forming apparatus provided with the fixing device.

[0021]

The above object is achieved by a fixing device and an image forming apparatus according to the present invention. In summary, the present invention provides at least a pair of fixing rotators disposed rotatably while being pressed against each other, and a cleaning member that contacts the surface of the fixing rotator to clean the fixing rotator. A fixing device that heats and fixes an unfixed image on the recording material by squeezing and conveying a recording material having an unfixed image at a pressure contact portion formed by the pair of fixing rotators. A fixing device wherein a contact surface between a surface of a rotating body and the cleaning member moves when the fixing rotating body stops.

According to another aspect of the present invention, there is provided an image forming means for forming an unfixed image on a recording material, and at least a pair of fixing rotating members rotatably disposed while being pressed against each other. A cleaning member that contacts the surface of the fixing rotator to clean the fixing rotator, and presses and conveys the recording material at a pressure contact portion formed by the pair of fixing rotators to form the recording material. In the image forming apparatus having a fixing device that heat-fixes the unfixed image formed thereon, the fixing device may be configured such that a surface of the fixing rotating body and a contact surface between the cleaning member and the fixing rotating body are An image forming apparatus is provided that moves when stopped.

According to another aspect of the present invention, there is provided an image forming means for forming an unfixed image on a recording material, and at least a pair of fixing rotations rotatably disposed while being pressed against each other. A fixing member that contacts the surface of the fixing rotator to clean the fixing rotator, and a unit that applies a release agent to the fixing rotator; In a case where a multi-color image is fixed in an image forming apparatus having a fixing device that performs heat fixing of the unfixed image formed on the recording material by nip-pressing and conveying the recording material at a pressure contact portion formed by the body, When the fixing rotator is stopped and the surface of the fixing rotator and the contact surface between the cleaning member are moved to fix a single-color image, the release agent application amount from the release agent applying unit is reduced. Between the surface of the fixing rotating body and the cleaning member. Sawamen an image forming apparatus, wherein a movement at the time of stop of the fixing rotary member.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fixing device and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS.

First, an electrophotographic color copying machine which is an image forming apparatus of the present embodiment will be described with reference to FIGS.

The color copying machine shown in FIG. 2 includes a document reading system I provided above, a latent image forming section II provided below the document reading system I, and a latent image forming section II. Developing means arranged in close proximity, that is, a rotary developing device III, and a recording material transport system IV provided from the right side of the apparatus main body 1 in the drawing to substantially the center of the apparatus main body are roughly classified. You.

In FIG. 3, the original reading system I scans the original by reciprocating right and left in the figure. Document reading system I
Is a document illumination lamp 103 for irradiating a document 101 placed on a document table glass 102, a short focus lens array 10
4. Filter 105, CCD 106, and housing 107
The document image is formed on the CCD 106 as the document is scanned. As a result, an electronic signal is output from the CCD 106, and the signal is processed by a signal processing circuit. The photosensitive drum 19 irradiates a laser beam based on the signal of each color as a result of the arithmetic processing, and visualization is performed.

The latent image forming section II is provided with a photosensitive drum 19 as a latent image carrier rotatable in the direction of arrow B in FIG. Above the photosensitive drum 19 and in the vicinity of its outer peripheral surface, a charge removing charger 20, a cleaning means 21, and a primary charger 23 are sequentially arranged from the upstream side to the downstream side in the rotation direction of the photosensitive drum 19, and As the image forming unit II, an image exposure unit 24 such as a laser beam scanner for forming an electrostatic latent image and an image exposure reflection unit 25 such as a mirror are provided on the outer peripheral surface of the photosensitive drum 19.

Therefore, if the image exposure means 24 is, for example, Y
When the laser beam E is irradiated based on the signals 3, 3, M3, C3, and BK3, the laser beam E is irradiated onto the photosensitive drum 19 via the image exposure / reflection means 25, and is uniformly charged by the primary charger 23. An electrostatic latent image is formed on the photosensitive drum 19, and is visualized as a developer image by the next rotary developing device III. Hereinafter, the rotary developing device III
Will be described.

The rotary developing device III is disposed at a position facing the outer peripheral surface of the photosensitive drum 19, and includes four types of developing devices in a rotatable housing (hereinafter referred to as a "rotary body") 26. It is configured to be mounted at four positions in the circumferential direction.

The four types of developing devices are a yellow developing device 27Y, a magenta developing device 27M, a cyan developing device 27C and a black developing device 27BK, respectively.
Development is performed with a developer of each color corresponding to the electrostatic latent image based on the signals of Y3, M3, C3, and BK3. Then, the developed visible image on the photosensitive drum 19 is transferred onto a recording material conveyed by the next recording material conveyance system IV. Hereinafter, the recording material transport system IV will be described.

The recording material transport system IV is as follows. First, an opening is formed in the right wall of the apparatus main body 1 in the drawing, and a recording material supply tray 2 which is detachable in the opening,
3 are provided so as to protrude partially outside the machine. Tray 2, 3
The paper feed rollers 4 and 5 are disposed almost directly above, and communicate with the paper feed rollers 4 and 5 and a transfer drum 15 that is a transfer means rotatable in the direction of arrow A disposed to the left. As described above, the paper feed roller 6 and the paper feed guides 7 and 8 are provided.

A contact roller 9, a gripper 10, a recording material separating charger 11, and a separating claw 12 are sequentially arranged from the upstream side to the downstream side in the rotation direction of the transfer drum 15. On the inner peripheral side of the transfer drum 15, a transfer charger 13 and a recording material separating charger 14 are provided.

The transfer drum 15 has a transfer sheet (not shown) made of polyvinylidene fluoride or the like affixed to a portion where the recording material is wound, so that the recording material is electrostatically adhered to the transfer sheet. It has become. Further, a transport belt 16 is disposed adjacent to the separation claw 12 on the upper right side of the transfer drum 15 in the drawing, and a fixing device 18 is disposed at an end (right) end of the transport belt 16 in the recording material transport direction. . Further, a discharge tray 17 that extends to the outside of the apparatus main body 1 and that is detachable from the apparatus main body 1 is disposed further rearward than the fixing device 18 in the transport direction.

The sequence of the entire image forming apparatus having the above-described configuration will be briefly described by taking a full-color mode as an example.

When the photosensitive drum 19 rotates in the direction of arrow B in FIG. 2, the photosensitive member of the photosensitive drum 19 is uniformly charged by the primary charger 23. In the image forming apparatus shown in FIG. 2, the operation speed of each unit (hereinafter referred to as “process speed”) is 160 mm / sec. When the photosensitive member is uniformly charged by the primary charger 23, the original 101
Image exposure is performed by the laser beam E modulated by the yellow image signal Y3, an electrostatic latent image is formed on the photosensitive drum 19, and the yellow developing device 27Y previously set at the developing position by the rotation of the rotating body 26 Thus, the electrostatic latent image is developed.

On the other hand, the recording material P conveyed via the paper feed guide 7, the paper feed roller 6, and the paper feed guide 8 is held at a predetermined timing by the gripper 10 of the transfer drum 15, and is used for contact. The transfer drum 15 is electrostatically wound around the roller 9 and the electrode facing the contact roller 9. The transfer drum 15 rotates in the direction of arrow A in FIG.
The developed image developed in Y is transferred by the transfer charger 13 at a position where the outer peripheral surface of the photosensitive drum 19 and the outer peripheral surface of the transfer drum 15 are in contact with each other. The transfer drum 15 continues to rotate as it is, and prepares for transfer of the next color (magenta in FIG. 2).

The photosensitive drum 19 is neutralized by a static eliminator 20 and is cleaned by a cleaning means 21 using a conventionally known blade method. Thereafter, the photosensitive drum 19 is charged again by a primary charger 23 and the following magenta image signal is used as described above. Undergoes image exposure.

The rotary developing device III rotates while an electrostatic latent image based on a magenta image signal is formed on the photosensitive drum 19 by image exposure, and fixes the magenta developing device 27M at the above-described predetermined developing position. A predetermined magenta development is performed.

Subsequently, the above-described process is carried out for the cyan and black colors. When the transfer of the four colors is completed, the four-color visual image formed on the recording material P is transferred to each of the chargers 20, 14, the gripping of the recording material P by the gripper 10 is released, and the recording material P
The sheet is separated from the transfer drum 15 by the separation claw 12, sent to the fixing device 18 by the conveyor belt 16, and fixed by heat and stress, and a series of full-color print sequences is completed to form a required full-color print image.

Next, the fixing device 18 of this embodiment will be described in more detail.

As shown in FIG. 4, the fixing device 18 includes a fixing roller 51 which is a rotatable fixing member and is rotatably disposed.
The configuration includes a pressure roller 52 serving as a pressure rotating body that rotates while being pressed against the fixing roller 51, a release agent application device 53 serving as a release agent supply / application unit, and roller cleaning devices 54 and 55.

Heaters 56 and 57 such as halogen lamps are provided inside the fixing roller 51 and the pressure roller 52, respectively. Further, thermistors 58 and 59 are disposed so as to be in contact with the fixing roller 51 and the pressure roller 52, respectively.
The fixing roller 51 is controlled by controlling the voltage to
In addition, the temperature of the surface of the pressure roller 52 is adjusted.

Further, a cleaning device 54 and a release agent applying device 53 are attached to the fixing roller 51, and the cleaning device 54 cleans toner and the like offset on the fixing roller 51, and
A release agent application device 53 applies a release agent, such as silicone oil, to the fixing roller 51.
This facilitates separation of the recording material P from the toner and prevents toner offset.

The cleaning device 54 includes a cleaning web 54a as a cleaning member made of a belt-shaped heat-resistant nonwoven fabric.
A pressing roller 54b for pressing the cleaning web 54a against the fixing roller 51;
And a cleaning web 54 to which toner or the like adheres and the cleaning ability is reduced.
The cleaning device 5 includes a take-up roller 54d that gradually takes up the a. The cleaning device 5 prevents the offset toner that has offset to the thermistor 58 from adhering to the thermistor 58 and causing a detection failure.
Reference numeral 4 is provided upstream of the thermistor 58 in the rotation direction of the fixing roller 51.

As a method of winding the cleaning web 54a, when a counter counts a predetermined number of copies, a web solenoid (not shown) is turned on and a one-way clutch is operated, so that the cleaning web 54a is rotated in a direction opposite to the roller rotation direction. It has been wound up by a predetermined amount. By taking up in the opposite direction, the cleaning web 54a is prevented from being taken up in the roller rotation direction.

The release agent applying device 53 pumps oil, which is a release agent such as silicone oil, from the oil tank 53a into the fixing roller 51 through an intermediate hole. Pipe 53b for dropping agent
And an oil leveling member 53c for making the dropped release agent uniform on the fixing roller 51, and a blade 53d for regulating the amount of the release agent applied to the recording material surface.

The pipe 53b is made of metal and is disposed in parallel with and above the axial direction of the fixing roller 51, and has holes at predetermined intervals, through which a releasing agent is supplied. It is dripped on. The dropped release agent is homogenized by an oil leveling member 53c made of a heat-resistant felt or the like, and is finally regulated by a blade 53d made of a fluoro rubber or the like located downstream of the releasing agent. The excess release agent regulated by the blade 53d flows over the surface of the blade 53d, is collected, and is reused.

Further, a cleaning web 55 similar to the cleaning device 54 of the fixing roller 1 is also provided on the pressure roller 52.
a, a cleaning device 55 including a pressing roller 55b, an unwinding roller 55c, a winding roller 55d, and the like, and cleaning of the toner adhered to the pressing roller 52 via the fixing roller 51 is performed.

The pressing roller 52 includes a pressing roller 5.
An oil removal blade 60, which is an elastic body for removing a release material that removes excess release material remaining on the surface 2, is in contact with the release member. If the oil removing blade 60 is not provided, the excess release agent accumulates in the nip between the fixing roller 51 and the pressure roller 52, causing stains on the recording material or slipping of the transparent laminating film for OHP. Poor entry into the nip occurs. As a material of the oil removing blade 60, Si rubber, fluoro rubber, or the like is used, and these blades are in contact with the rotating direction of the pressure roller 52 in a forward direction or a reverse direction with an appropriate amount of approach.

In the above configuration, when the recording material P is conveyed, the fixing roller 51 and the pressure roller 52 rotate, and silicone oil is applied to the surface of the fixing roller 51 as a release agent, so that the recording material P is fixed. Roller 51 and pressure roller 52
When passing through the nip, that is, the pressure contact portion, pressure and temperature are applied from both front and back surfaces at a substantially constant pressure and temperature, and the unfixed image on the recording material surface is melted and fixed to form a full color image on the recording material P Is done. The recording material P on which the image has been fixed is separated from the pressure roller 52 by the lower separation claw 68, and is discharged out of the apparatus.

Next, the features of the present invention will be described mainly with reference to the sequence diagram of the fixing roller and the web winding shaft shown in FIG.

When the copy button is pressed to start the copying operation, the image is formed as described above, and the fixing roller 51 is formed.
The recording material P carrying an unfixed image is conveyed to the nip between the recording material P and the pressure roller 52. Here, the fixing roller 51 and the pressure roller 52 rotate at an appropriate fixing speed just before the recording material is conveyed to the nip, and the unfixed image is fixed.

Then, the fixing roller 51 and the pressure roller 52 stop rotating until the fixing of the recording material P is completed and immediately before the next recording material is conveyed to the fixing nip, that is, between the sheets. In this stopped state, the cleaning webs 54a and 55a are wound up.

By winding the cleaning webs 54a and 55a while the rollers 51 and 52 stop rotating, the frictional force between the rollers 51 and 52 and the cleaning webs 54a and 55a is reduced. Therefore, stable web feeding is possible, that is, a web winding amount can be stably obtained.

The cleaning webs 54a, 55a
Is not separated from the rollers 51 and 52 and is not taken up, so that toner may fall off from the cleaning webs 54a and 55a to cause an image defect, or the cleaning web 54
a, the members downstream of 55a are not contaminated.

Further, even if the amount of oil applied to the fixing roller 51 becomes 20 mg / A4, the web is not taken up stably without having a web attaching / detaching mechanism, so that space saving, cost reduction and simplification of the apparatus can be achieved. It has become possible. In addition, the load on the gears of the drive system related to the fixing device is reduced, damage can be prevented, and a longer life can be achieved.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIGS.

In the present embodiment, in the color image forming apparatus using one photosensitive drum 19 as in the image forming apparatus shown in FIG. 2, each cleaning web of the fixing roller 51 and the pressure roller 52 is used. Regarding the winding timings of 54a and 55a, the winding is controlled in a state where the fixing roller 51 and the pressure roller 52 are stopped.

The control of this embodiment will be described with reference to the flowchart of FIG.
0), the copy button is depressed (S1), and when the copy operation is started, when the image is read, it is determined whether full-color image formation or single-color image formation (S2). At this time,
Since one photosensitive drum is used, four-color image formation must be performed in full-color image formation, and the number of recording materials conveyed to the fixing device is smaller than in single-color image formation. Therefore, during the formation of a full-color image, the interval between the conveyed recording materials is widened, so that the fixing roller 51 and the pressure roller 52 can be stopped during that time, that is, between papers.

That is, as shown in FIG. 6, at the time of forming a full-color image, with the fixing roller 51 and the pressure roller 52 stopped between the sheets (S3), the web solenoid is turned on to take up the cleaning webs 54a, 55a. (S4), the frictional force is smaller than when the fixing roller 51 and the pressure roller 52 are rotating in the direction opposite to the direction in which the cleaning webs 54a and 55a are wound. And pressure roller 52
The webs 54a and 55a are not pulled back in a direction opposite to the rotation direction of the above, and stable web feeding can be performed.

At the time of forming a single-color image, as shown in FIG. 7, when fixing of a predetermined number of sheets is completed, several sheets are thinned out, and the fixing roller 51 and the pressure roller 52 are stopped during that time (S5). The web solenoid is turned on to wind up the cleaning webs 54a and 55a (S4), and the roller is rotated again to perform fixing, thereby enabling stable web feeding.

When a single-color image is formed, the amount of toner offset to the fixing roller 51 is smaller than when a full-color image is formed, so that the amount of dirt on the cleaning webs 54a and 55a is reduced. For this reason, the interval of the predetermined number of sheets until the web is wound is also increased, and it is sufficient to wind every several copies when forming a full-color image, whereas it is sufficient every several tens of copies. As a result, the number of times the recording material is thinned out may be small when actually forming a monochromatic image.

By doing so, even if the amount of oil applied to the fixing roller becomes 20 mg / A4 or less, the web can be wound up stably without the provision of a web attaching / detaching mechanism, thereby saving space. Cost reduction has become possible. In addition, the load on the gear has been reduced, and breakage can be prevented.

Further, since there is no web attaching / detaching mechanism, the problem which has conventionally occurred does not occur.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG.

In the present embodiment, when forming a monochromatic image of the first embodiment, the supply amount of oil (release agent) by the release agent application device is increased so that the fixing roller 51, the pressure roller 52 and the cleaning web The web feed is stabilized by reducing the frictional force between the webs 54a and 55a.

In FIG. 8, as in the second embodiment, it is determined whether full-color image formation or single-color image formation is to be performed (S
2) If it is determined that a full-color image is to be formed, with the fixing roller 51 and the pressure roller 52 stopped between sheets (S3), the web solenoid is turned on to wind up the cleaning webs 54a and 55a. (S4).

On the other hand, when it is determined that a single-color image is to be formed, the amount of oil dripped from the hole of the pipe 53b is increased by increasing the cycle of the pump for pumping the pipe 53b of the release agent applying device 53 (S15). . This increases the amount of the release agent supplied to the release agent leveling member 53c and the regulating blade 53d.

The release agent supplied dropwise is supplied to the fixing roller 51.
Since the temperature is usually lower than the surface temperature of the liquid, the viscosity increases. In the regulating blade 53d, the higher the viscosity,
Since the followability between the fixing roller 51 and the release agent increases, the regulated amount increases. Here, when the dropped high viscosity release agent increases, the release amount of the release agent from the regulating blade 53d increases, and the release agent amount applied to the recording material also increases.

As a result, since the amount of the release agent remaining on the fixing roller 51 and the pressure roller 52 after fixing is increased, the frictional force between the fixing roller 51 and the pressure roller 52 and the webs 54a and 55a is reduced.

By doing so, the web can be wound up stably without providing a web attaching / detaching mechanism, and space and cost can be reduced.

[0074]

As is apparent from the above description, according to the present invention, the contact surface between the surface of the fixing rotator and the cleaning member moves when the fixing rotator is stopped, When the color image is fixed, the contact surface between the surface of the fixing rotator and the cleaning member is moved when the fixing rotator is stopped, and when the monochromatic image is fixed, the release agent applying unit is used. The amount of the release agent applied from the fixing member is increased, and the contact surface between the surface of the fixing member and the cleaning member moves when the fixing member is stopped. The frictional force of the rotating body can be suppressed, the damage of gears and the like can be prevented, and the life can be extended. Further, it is possible to stably obtain a winding amount of the cleaning member with a simple configuration, prevent image defects due to insufficient cleaning, obtain a high quality image, save space, and reduce cost. Can be achieved. Further, it is possible to prevent the toner attached to the cleaning member from damaging the fixing rotating body.

[Brief description of the drawings]

FIG. 1 is a sequence diagram showing a control sequence according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an image forming apparatus according to a first embodiment.

FIG. 3 is a schematic configuration diagram illustrating a document reading system of the image forming apparatus of FIG. 2;

FIG. 4 is a configuration diagram illustrating a fixing device according to the first embodiment.

FIG. 5 is a flowchart showing a control flow according to a second embodiment of the present invention.

FIG. 6 is a sequence diagram showing a control sequence at the time of forming a monochrome image in a second embodiment of the present invention.

FIG. 7 is a sequence diagram showing a control sequence when a full-color image is formed in a second embodiment of the present invention.

FIG. 8 is a sequence diagram showing a control sequence at the time of forming a monochrome image in a third embodiment of the present invention.

FIG. 9 is a configuration diagram illustrating an example of a conventional fixing device.

[Explanation of symbols]

 18 Fixing Device 51 Fixing Roller (Fixing Rotator) 52 Pressure Roller (Fixing Rotator) 53 Release Agent Coating Device 54, 55 Cleaning Device 54a, 55a Cleaning Web (Cleaning Member)

Continued on the front page (72) Inventor Mitsuhiro Ota 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H033 AA08 AA21 AA26 BA51 BA57 CA21

Claims (3)

[Claims] At least a pair of fixing rotators disposed rotatably while being pressed against each other, and a cleaning member that contacts a surface of the fixing rotator to clean the fixing rotator. A fixing device that heats and fixes an unfixed image on the recording material by nipping and conveying a recording material having an unfixed image at a pressure contact portion formed by the pair of fixing rotators; A fixing device wherein a contact surface between a front surface and the cleaning member moves when the fixing rotating body stops. 2. An image forming means for forming an unfixed image on a recording material, wherein at least a pair of fixing rotators rotatably disposed while being pressed against each other, and a surface of the fixing rotator. And a cleaning member for cleaning the fixing rotator by contacting the recording material with the pressing member formed by the pair of fixing rotators. In the image forming apparatus having a fixing device for performing heat fixing of an image, the fixing device is characterized in that a contact surface between a surface of the fixing rotating body and the cleaning member moves when the fixing rotating body is stopped. Image forming apparatus. 3. An image forming means for forming an unfixed image on a recording material, and at least a pair of fixing rotators rotatably disposed while being pressed against each other, and a surface of the fixing rotator. A cleaning member that contacts the fixing rotator to clean the fixing rotator, and a unit that applies a release agent to the fixing rotator. The recording material is pressed by a pressure contact portion formed by the pair of fixing rotators. In the image forming apparatus having a fixing device that heats and fixes the unfixed image formed on the recording material by nipping and conveying, when fixing a multi-color image, the surface of the fixing rotating body and the cleaning are fixed. When the fixing rotating body is stopped, the contact surface with the member is moved, and when a single-color image is fixed, the release agent application amount from the release agent applying unit is increased, and the fixing rotating body is When the contact surface between the surface and the cleaning member is stopped when the fixing rotating body is stopped. An image forming apparatus characterized by dynamic.