JPH08328422A - Fixing device and image forming device - Google Patents

Abstract

PURPOSE: To provide a fixing device and an image forming device in which the surface of a pressure roller is excellently cleaned without damaging the pressure roller. CONSTITUTION: A 1st cleaning roller 65a having an elastic body layer whose releasing property is inferior to that of the material of the surface layer of the pressure roller 52 is made in press-contact with the pressure roller 52 and further a 2nd cleaning roller 65b made of metal is allowed to abut on the 1st cleaning roller 65a. Then, an oil removing blade 60 is disposed to freely contact with/separate from the roller 52, and it is separated from the roller 52 in the case other than the case recording material is a transparent laminated film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device for fixing an unfixed toner image by passing a recording material having an unfixed toner image between a fixing roller and a pressure roller which are pressed against each other. The present invention relates to an image forming apparatus having a heat fixing device, and more particularly to a color image forming apparatus having a heat fixing device and a plurality of image forming means.

[0002]

2. Description of the Related Art As an example of an image forming apparatus as described above, FIGS. 5 and 6 show a four-drum laser beam printer having a plurality of optical scanning means.

As shown in FIG. 5, the printer is an image forming means having a developing device and the like around an electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") which is a latent image carrier. Four image forming stations that are barrels are provided, and the image formed on each of the image forming stations on the photosensitive drum is a recording material such as paper (hereinafter referred to as a recording material) on a conveying unit that moves and passes adjacent to the photosensitive drum. , Transfer paper) P.

Further, as shown in FIG. 6, the photosensitive drums 1a, 1b, 1c, and 1c are provided on the image forming stations Pa, Pb, Pc, and Pd that form images of magenta, cyan, yellow, and black, respectively. 1d is arranged, and each photosensitive drum is rotatable in the arrow direction.
Further, around the photosensitive drums 1a, 1b, 1c, 1d, chargers 12a, 12b, 12c, 12d, developing devices 2a, 2b, 2c, 2d, and cleaners 4a, 4 are provided.
b, 4c, and 4d are sequentially arranged along the rotation direction of the photosensitive drum, and the transfer unit 3 is provided below each photosensitive drum.
Is provided. The transfer section 3 has a transfer belt 31 which is a recording material conveying means common to each image forming station, and transfer chargers 3a, 3b, 3c and 3d.

In the printer as described above, the transfer paper P supplied from the paper supply cassette 61 as the recording material supply means shown in FIG. 5 is supported on the transfer belt 31 and is conveyed to each image forming station. The toner images of the respective colors formed on the respective photosensitive drums are sequentially transferred. When this transfer step is completed, the paper P is separated from the transfer belt 31 and is conveyed to the fixing device 5 by a conveyor belt 62 which is a recording material guide means.

The fixing device 5, as shown in detail in FIG.
A fixing roller 51 that is a rotatably arranged rotating body for fixing.
A pressure roller 52, which is a rotary body for pressure application, which rotates while being in pressure contact with the fixing roller 51; a release agent applying device 53, which is a release agent supplying / applying means; and roller cleaning devices 54, 5.
It has a configuration having 5. A heater 5 such as a halogen lamp is provided inside the fixing roller 51 and the pressure roller 52.
6, 57 are arranged respectively. The fixing roller 51 and the pressure roller 52 have a thermistor 58,
59 are arranged in contact with each other, and the temperature of the surface of the fixing roller 51 and the pressure roller 52 is adjusted by controlling the voltage to the heater 56 and the heater 57 via the temperature adjusting circuit.

Further, a cleaning device 54 and a release agent applying device 53 are attached to the fixing roller 51, and the offset toner on the fixing roller 51 is cleaned by the cleaning device 54.
The releasing agent applying device 53 applies silicone oil or the like as a releasing agent to the fixing roller 51, and the fixing roller 51
The transfer paper P is easily separated from the toner and the offset of the toner is prevented.

The cleaning device 54 includes a cleaning web 54a made of a band-shaped heat-resistant nonwoven fabric, and a pressing roller 5 for pressing the cleaning web 54a against the fixing roller 51.
4b, an unwinding roller 54c that unwinds a new cleaning web 54a, and a winding roller 54d that gradually winds up the cleaning web 54a that has deteriorated cleaning ability due to toner or the like. The cleaning device 54 is provided on the upstream side of the thermistor 58 in the rotation direction of the fixing roller 51 so that the offset toner does not adhere to the thermistor 58 and the detection failure occurs in the thermistor 58.

The release agent applying device 53 includes an oil tank 53a having a release agent such as silicone oil, pumping rollers 53b and 53c for pumping oil as a release agent from the oil tank 53a, and pumping rollers 53b and 53.
It is composed of a coating roller 53d for coating the fixing roller 51 with the oil from c and a blade 53e for controlling the amount of oil coating from the coating roller 53d. In order to achieve this, the release agent applying device 53 is arranged downstream of the thermistor 58 in the rotation direction of the fixing roller 51. The application roller 53d is a rotatable roller in which the surface of sponge rubber is covered with silicone rubber, and contacts the fixing roller 51 as necessary to apply oil to the fixing roller 51.

The pressure roller 52 also includes the fixing roller 1
Cleaning web 5 similar to the cleaning device 54 of
5a, a pressing roller 55b, an unwinding roller 55c, a take-up roller 55d, and the like are attached to clean the toner adhering to the pressure roller 52 via the fixing roller 51.

The pressure roller 52 includes a pressure roller 5
An oil removing blade 60, which is an elastic body for removing the release agent that removes the excess release agent remaining on the surface 2, is in contact. If the oil removing blade 60 is not provided, the excess release agent collects in the nip between the fixing roller 51 and the pressure roller 52 and causes stains on the recording material, or the transparent laminate film for OHP slips to the nip. The entry failure occurs. As the material of the oil removing blade 60, Si rubber, fluororubber, or the like is used, and these blades are in contact with the pressing roller 52 in the forward direction or the reverse direction with an appropriate amount of advance.

In this state, when the transfer paper P is conveyed, the fixing roller 51 and the pressure roller 52 rotate at a constant speed, and the surface of the fixing roller 51 is coated with silicone oil as a release agent. When P passes between the fixing roller 51 and the pressure roller 52, the unfixed toner image on the paper surface is melted and fixed by being pressed and heated from both front and back surfaces at a substantially constant pressure and temperature, and the transfer paper P A full color image is formed on top. The transfer sheet P on which the image is fixed is separated from the pressure roller 52 by the lower separation claw 68 and is discharged to the outside of the machine.

[0013]

However, in the conventional image forming apparatus, the paper dust and the toner adhered to the pressure roller 52 at the time of fixing are cleaned by using the cleaning web 55a made of a non-woven fabric and used at the time of fixing. Since the excess oil remaining on the pressure roller 52 was removed using the oil removing blade 60, the web 55a and the oil removing blade 60 are always in contact with the pressure roller 52, and the number of copies is As the amount of the toner increases, the pressure roller 52 may be damaged due to the rubbing. Further, the paper dust and the toner from the pressure roller 52 are also fixed to the web 55a oil removing blade 60, and the lump thereof may cause a scratch, which may make it difficult to guarantee a high durability life. It was

Therefore, the present invention provides a fixing device and an image forming apparatus capable of satisfactorily cleaning the surface of the pressure roller and removing excess oil without causing damage to the pressure roller. It is an object.

[0015]

According to the first invention of the present application, the above object is to provide a rotating body pair of a fixing rotating body and a pressing rotating body which are rotatably arranged while being in pressure contact with each other. In a fixing device which has a recording material having an unfixed image at a pressure contact portion formed by the pair of rotating members and heats and fixes the unfixed image on the recording material, the pressing member is pressed against the rotating member for pressure. However, this is achieved by having a cleaning rotary member that is rotatably disposed, and a release agent removing elastic blade that can be brought into contact with and separated from the pressurizing rotary member.

According to the second invention of the present application,
The above object is achieved in the first aspect of the present invention, in which the surface layer of the cleaning rotator is an elastic body and the surface free energy of the elastic body is higher than the surface free energy of the pressing rotator surface layer.

Further, according to the third invention of the present application,
The above object is achieved in the first or second invention by having a metallic rotating body that is rotatably disposed while being in pressure contact with the cleaning rotating body.

According to the fourth invention of the present application,
In the first aspect of the present invention, the elastic blade for removing the release agent is in contact with the rotating body for pressing when the recording material is a transparent laminated film, and the rotating blade for pressing when forming a single-sided image in the case of plain paper. Achieved by being set away from the body.

Further, according to the fifth invention of the present application,
The above-mentioned object is achieved in the above-mentioned first invention by controlling contact / separation of the elastic material blade for removing the release agent between the front surface and the back surface during double-sided image formation.

According to the sixth invention of the present application,
The above-mentioned object is, in any one of the above-mentioned first to fifth inventions, that the contact / separation control of the release agent-removing elastic blade is at most 10 from the first sheet on the surface during double-sided image formation.
This can be achieved by contacting the pressing rotary member only during the first sheet.

Further, according to the seventh invention of the present application,
The above-mentioned object has a developing means for forming an unfixed image on a recording material, and a rotating body pair of a rotating body for fixing and a rotating body for pressing which are rotatably arranged while being in pressure contact with each other. An image forming apparatus comprising: a fixing device configured to press and convey the recording material having the unfixed image at a pressure contact portion formed by a pair to heat and fix the unfixed image on the recording material. This is achieved by having a cleaning rotary member that is rotatably arranged while being pressed against the pressure rotary member, and a release agent removing elastic blade that can be brought into contact with and separated from the pressurizing rotary member.

[0022]

According to the first invention of the present application, the cleaning rotary member rotatably disposed while being in pressure contact with the pressurizing rotary member removes the paper dust and the like from the pressurizing rotary member. Excessive mold release agent on the pressurizing rotor is squeezed down at the pressure contact part with the cleaning rotor, and is evened out, so that the release agent removing elastic blade always contacts the pressurizing rotor. There is no need to keep it, and scratches do not occur on the surface of the rotating body for pressing.

According to the second invention of the present application,
In the first aspect of the invention, the surface layer of the cleaning rotary member is an elastic body, and the surface free energy of the elastic member is higher than the surface free energy of the pressing rotor surface layer. Also, the toner adhering to the pressing rotary member is transferred to the cleaning rotary member and removed.

Further, according to the third invention of the present application,
In the first invention or the second invention, the metal rotating body rotatably arranged while being pressed against the cleaning rotating body has a surface free energy higher than that of the cleaning rotating body. The toner transferred from the pressurizing rotary member to the body moves to the metallic rotary member, and the toner on the cleaning rotary member is removed.

According to the fourth invention of the present application,
In the first aspect of the invention, the elastic blade for removing the release agent is in contact with the rotating body for pressing when the recording material is a transparent laminate film, so that the excess releasing agent which is not removed only by the rotating body for cleaning is used. Since it is surely removed and is separated from the pressing rotary member when forming a single-sided image in the case of plain paper, no scratch is generated on the pressing rotary member.

Further, according to the fifth invention of the present application,
In the above-mentioned first invention, since the contact / separation control of the elastic body blade for removing the release agent is different between the front surface and the back surface during double-sided image formation, the release agent amount on the rotating body for pressurization is appropriately adjusted. This prevents the occurrence of streaks due to the occurrence of offsets.

According to the sixth invention of the present application,
In any one of the first to fifth inventions,
Since the contact / separation control of the elastic body blade for releasing the release agent is set so as to make contact with the pressure-applying rotary member only between the first first sheet and the tenth sheet at the time of double-sided image formation, The excess release agent from the first sheet to the tenth sheet is surely removed. Since there is almost no excess release agent after the eleventh sheet, the elastic body blade for removing the release agent is separated from the rotating body for pressurization. Prevents the generation of scratches on the surface of the pressure rotor.

Further, according to the seventh invention of the present application,
The cleaning rotary member rotatably arranged while being pressed against the pressurizing rotary member of the fixing device removes paper dust and the like on the pressurizing rotary member, and further, the excess release agent on the pressurizing rotary member is Since it is squeezed down at the pressure contact portion with the cleaning rotator and evenly leveled, it is not necessary to keep the release agent removing elastic blade in contact with the pressure rotator at all times. Good images are formed without causing scratches.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram of the fixing device according to the present embodiment. The same parts as those of the conventional example shown in FIG.

In the present embodiment, as shown in FIG. 1, the cleaning device for the pressure roller 52, which is the pressure rotating member, is changed from a conventional non-woven fabric roller to a roller, and the removal of the oil, which is the elastic blade for removing the release agent, is performed. Blade 60 to pressure roller 5
The pressure roller 52 can be prevented from being damaged by contacting the pressure roller 52 only when necessary. In FIG. 1, reference numeral 65 is a pressure roller cleaning device, 65a is a first cleaning roller which is a cleaning rotary member, and 65b is a second cleaning roller which is a metallic rotary member. The first cleaning roller 65a is a rubber roller having a rubber layer on a core metal such as aluminum or iron.
The surface rubber material is Si rubber, fluororubber, etc., toner,
The releasability is inferior to the surface layer material used for the pressure roller 52.

Specifically, the LT on the surface of the pressure roller 52 is
When Si rubber such as V or RTV is used, the surface layer of the first cleaning roller 65a is preferably LTV, RTV, Si rubber or the like containing a large amount of filler such as HTVSi rubber or silica.

With this structure, the surface free energy of the first cleaning roller 65a is higher than that of the surface rubber of the pressure roller 52, so that the toner adhered on the pressure roller 52 is not absorbed by the toner of the first cleaning roller 65a. It moves to the surface layer and cleaning is performed. Also,
At the same time, the first cleaning roller 65a is the pressure roller 52.
Since the oil is pressed against the pressure roller 52 with a proper pressure and is rotating, the excess oil on the pressure roller 52 is squeezed down at the nip between the first cleaning roller 65a and the pressure roller 52, and is evened out. No oil streaks are generated on the pressure roller 52.

Next, as the second cleaning roller 65b, a roller having a higher surface free energy than the surface layer of the first cleaning roller 65a and having a toner releasing property worse is used. Specifically, a metal roller such as aluminum, SUS, or iron is used.
The toner transferred from 2 further transfers to the second cleaning roller 65b, and the toner does not always adhere to the surface of the first cleaning roller 65a. As a result, oil streaks due to toner adhesion on the surface of the first cleaning roller 65a do not occur. Further, the blade 65c is in contact with the first cleaning roller 65a.
The cleaning roller 65a is further cleaned, and the first
The oil on the cleaning roller 65a is made uniform.

With such a configuration, the pressure roller 5
Since the second excess oil can be scraped off and cleaned at the same time, in the case of paper, the oil removing blade 60 can be separated from the pressure roller 52.

However, in the case of a transparent laminate film for OHP, the conditions are more severe and the cleaning unit 65 alone has a poorer ability to remove surplus oil than the conventional example, resulting in defective entry due to oil slip. Therefore, the oil removing blade 60 is attached to the pressure roller 52.
The transparent laminated film is brought into contact with and separated from the contact surface.

That is, as shown in FIG. 2, when the copy button is turned on (step S2) from the standby state (step S1), it is judged whether the recording material is paper (step S3), and if it is paper. The oil removal blade 6
0 is separated from the pressure roller 52 (step S4), fixing is performed in that state (step S5), and copying is completed (step S6). On the other hand, when the recording material is a transparent laminated film, the oil removing blade 60 is brought into contact with the pressure roller 52 (step S7), and after the fixing is completed (step S8), the oil removing blade 60 is moved to the pressure roller 5.
It is separated from 2 (step S9), and the copy is finished (step S6).

As a result, even in the case of a transparent laminated film for OHP, no defective entry occurs, and the oil removing blade 60 is provided with the pressure roller 52 during normal copying of paper.
Since the pressure roller 52 is separated from the conventional example, scratches on the pressure roller 52 are reduced as compared with the conventional example.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, when a double-sided image is formed, the contact and separation of the oil removing blade 60 are controlled on the first and second sides of the image. In the conventional fixing device, Si oil that adheres to the paper when fixing the first surface (front surface) in the double-sided image forming mode adheres to the photosensitive drums 1a to 1d during image formation for the second surface (rear surface) in the same mode and performs cleaning. In order to prevent the occurrence of defects, the oil application amount is controlled to be small in the double-sided image forming mode. However, when the second side is fixed with the same setting as the first side, when an image with a large amount of toner is on the first side, the image may be offset to the pressure roller 52 during re-fixing. Therefore, in this embodiment,
When fixing the image on the first side in the double-sided image forming mode, the oil removing blade 60 is contacted to increase the oil scraping ability, and the amount of oil applied is reduced. When fixing the image on the second side, the oil removing blade 60 is released. The amount of oil on the pressure roller 52 is increased to prevent offset. That is, in FIG. 3, when the copy start button is pressed during image formation on the first side, the oil removal blade contact / separation solenoid (not shown) is turned on immediately before the recording material enters the fixing nip, and the oil removal blade 60 is removed. The excess oil is scraped off by bringing it into contact with the pressure roller 52. On the other hand, the recording material is the fixing roller 51 and the pressure roller 5.
After exiting the nip with 2, the solenoid is turned off and the oil removing blade 60 is separated from the pressure roller 52. Then, when the copy button for image formation on the second side is pressed, the contact / separation solenoid remains OFF this time, and the oil removal blade 60 remains separated from the pressure roller 52.

By so doing, cleaning failure due to oil transfer to the photosensitive drums 1a to 1d does not occur, and image peeling does not occur at the time of fixing the second surface. Further, the oil removing blade 60 is also in contact with the pressure roller 52 for a shorter period of time than in the conventional case, so that the pressure roller 52 is also effectively scratched.

(Third Embodiment) In this embodiment, as compared with the second embodiment, the oil removing blade 60 has a pressure roller 52.
The control time is shown in FIG. In the second embodiment, the oil removing blade 6
0 is the pressure roller 5 immediately before the recording material enters the fixing nip.
It was kept in contact with the pressure roller 52 until it was in contact with No. 2 and then the fixing of the first surface of both surfaces was completed. However, the pressure roller 5
When the recording material is continuously fixed, the surplus oil on 2 is taken away by the first few sheets (up to about the fifth sheet), and is scarcely left behind. Therefore, when fixing the first surface of both sides continuously, if the oil removing blade 60 is in contact with the pressure roller 52 until the first five sheets, almost no surplus oil remains on the pressure roller 52 after that. Even when the oil removing blade 60 is separated from the pressure roller 52, oil transfer does not occur. Further, since the contact time of the oil removing blade 60 with the pressure roller 52 is further shorter than that in the second embodiment, it is more effective against the damage of the pressure roller 52. The number of the oil removing blades 60 in contact at this time is not limited to the fifth sheet, because it depends on the amount of oil applied. Disappear.

When the number of continuously set sheets is smaller than the number of oil removing blades 60 in contact with the pressure roller 52, the same as in the second embodiment.

[0043]

As described above, the first aspect of the present application
According to the invention, since the cleaning rotary member rotatably arranged while being pressed against the pressurizing rotary member and the release agent removing elastic blade are provided, scratches are generated on the pressurizing rotary member surface. Without this, it is possible to reliably clean the paper powder, the toner, and the like on the surface of the pressing rotary member, and prevent the generation of streaks due to the release agent.

According to the second invention of the present application,
In the first aspect of the invention, the surface layer of the cleaning rotary member is an elastic body, and the surface free energy of the elastic member is higher than the surface free energy of the pressing rotor surface layer. Also, it is possible to satisfactorily remove the toner adhering to the pressing rotary member.

Further, according to the third invention of the present application,
In the first invention or the second invention, the metal rotating body rotatably arranged while being pressed against the cleaning rotating body has a surface free energy higher than that of the cleaning rotating body. The toner transferred from the pressing rotary member to the body moves to the metal rotary member, and the toner on the cleaning rotary member can be removed.

According to the fourth invention of the present application,
In the first aspect of the invention, the elastic blade for removing the release agent is in contact with the rotating body for pressing when the recording material is a transparent laminate film, so that the excess releasing agent which is not removed only by the rotating body for cleaning is used. It is reliably removed, and in the case of plain paper, it is separated from the pressing rotary member during single-sided image formation, so that the occurrence of scratches on the pressing rotary member can be prevented.

Further, according to the fifth invention of the present application,
In the above-mentioned first invention, since the contact / separation control of the elastic body blade for removing the release agent is different between the front surface and the back surface during double-sided image formation, the amount of the release agent on the pressing rotary member is appropriately adjusted to It is possible to prevent the occurrence of offset while preventing the generation of streaks due to the agent.

According to the sixth invention of the present application,
In any one of the first to fifth inventions,
Since the contact / separation control of the elastic body blade for releasing the release agent is set so as to make contact with the pressure-applying rotary member only between the first first sheet and the tenth sheet at the time of double-sided image formation, The excess release agent from the first sheet to the tenth sheet is surely removed. Since there is almost no excess release agent after the eleventh sheet, the elastic body blade for removing the release agent is separated from the rotating body for pressurization. It is possible to prevent the generation of scratches on the surface of the pressure rotating body.

Further, according to the seventh invention of the present application,
The cleaning rotary member rotatably arranged while being pressed against the pressurizing rotary member of the fixing device removes paper dust and the like on the pressurizing rotary member, and further, the excess release agent on the pressurizing rotary member is Since it is squeezed down at the pressure contact portion with the cleaning rotator and evenly leveled, it is not necessary to keep the release agent removing elastic blade in contact with the pressure rotator at all times. Good images can be formed without causing scratches.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a fixing device according to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart in the first embodiment of the present invention.

FIG. 3 is a timing chart in the second embodiment of the present invention.

FIG. 4 is a timing chart in the third embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional full-color copying machine.

FIG. 6 is a schematic sectional view of a conventional full-color copying machine.

FIG. 7 is a schematic sectional view of a conventional fixing device.

[Explanation of symbols]

51 Fixing Roller (Rotating Body for Fixing) 52 Pressure Roller (Rotating Body for Pressing) 60 Oil Removal Blade (Elastic Body Blade for Removing Release Agent) 65a First Cleaning Roller (Rotating Body for Cleaning) 65b Second Cleaning Roller ( Metal rotating body) P Transfer paper (recording material)

Claims (7)

[Claims] 1. A recording material having a rotating body pair of a fixing rotating body and a pressing rotating body which are rotatably arranged while being in pressure contact with each other, and which has an unfixed image at a pressure contact portion formed by the rotating body pair. In a fixing device that conveys an unfixed image on the recording material by heating under pressure, a cleaning rotator disposed rotatably while being in pressure contact with the pressure rotator, and the pressure rotator. A fixing device comprising a release agent removing elastic blade that can be brought into and out of contact with. 2. The fixing device according to claim 1, wherein the surface layer of the cleaning rotary member is an elastic member, and the surface free energy of the elastic member is higher than the surface free energy of the surface layer of the pressing rotary member. 3. The fixing device according to claim 1, further comprising a metallic rotating body that is rotatably arranged while being pressed against the cleaning rotating body. 4. The elastic blade for removing the release agent is set so as to come into contact with the pressing rotary member when the recording material is a transparent laminated film, and to separate from the pressing rotary member when forming a single-sided image on plain paper. The fixing device according to claim 1, wherein the fixing device is provided. 5. The fixing device according to claim 1, wherein contact control of the release agent removing elastic blade is different between the front surface and the back surface during double-sided image formation. 6. The contact / separation control of the release agent removing elastic blade is performed from the first sheet on the front surface to 1 at most during double-sided image formation.
The fixing device according to any one of claims 1 to 5, wherein the fixing device is brought into contact with the pressing rotary member only during the 0th sheet. 7. An image forming means for forming an unfixed image on a recording material, and a rotating body pair of a rotating body for fixing and a rotating body for pressing which are rotatably arranged in pressure contact with each other. An image forming apparatus comprising: a fixing device configured to press and convey the recording material having the unfixed image at a pressure contact portion formed by the body pair to heat and fix the unfixed image on the recording material. An image forming apparatus comprising: a cleaning rotator, which is rotatably arranged while being in pressure contact with a pressure rotator, and a release agent removing elastic blade capable of contacting and separating from the pressure rotator. .