JPH0869199A - Cleaning device for fixing device - Google Patents

Abstract

PURPOSE: To provide a cleaning device for fixing device capable of preventing the toner from being inversely transferred form a backup roller with a simple constitution and having excellent durability. CONSTITUTION: The cleaning device for the fixing device 50 adopted to the image forming device is provided with the cleaning roller 54 held in contact with the fixing roller 51 opposing at least the toner carrying surface of paired fixing rollers 51 and 52 for fixing the toner image on the transfer paper P, and the backup roller 55 held in contact with cleaning roller 54, and is furnished with the blade 56 for scraping off and recovering the depositions stuck on the cleaning roller 54.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device cleaning apparatus applied to an image forming apparatus such as a copying machine, a facsimile, a printer, a printing machine or the like.

[0002]

2. Description of the Related Art A cleaning roller having the same or lower releasability to toner as a fixing roller is brought into pressure contact with a fixing roller and a backup roller having a lower releasability to toner than a cleaning roller.
A cleaning device for a fixing device in which the temperature of the fixing roller is set to be equal to or lower than the melting point of the toner is disclosed in Japanese Patent Laid-Open No. 61-86776, and a cleaning roller having the same releasability for toner as the fixing roller is used as the fixing roller. The technique of press contacting with is disclosed in JP-A-61-217773.

[0003]

The above-mentioned device has a releasability due to the melted state of the toner adhering to the cleaning roller and the backup roller immediately after the image forming apparatus is turned on or when copying the first sheet after the standby state. The effect of
There is a problem that the toner is reversely transferred from the backup roller to the fixing roller to cause an offset phenomenon.

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a cleaning device for a fixing device which can prevent the reverse rotation of toner from the backup roller and has a simple structure. To aim.

[0005]

According to the first aspect of the present invention,
A cleaning device for a fixing device used in an image forming apparatus, the cleaning roller contacting at least a fixing roller facing a toner carrying surface of a fixing roller pair fixing a toner image on a transfer sheet, and a backup roller contacting the cleaning roller. In the cleaning device of the fixing device having the above, a blade for scraping off and collecting the adhering matter adhering to the cleaning roller is provided.

According to a second aspect of the present invention, in the cleaning device of the fixing device of the image forming apparatus according to the first aspect, the blade is located at a position where it abuts against the cleaning roller and at a position where it is separated from the cleaning roller. It is characterized by having a rocking means for rocking.

According to a third aspect of the present invention, in the cleaning device of the fixing device according to the second aspect, the blade is
A fixing device including control means for controlling the swinging device to swing the image forming device to the contact position when the image forming device starts up and to the separated position when fixing the toner image. Cleaning device.

According to a fourth aspect of the present invention, in the cleaning device for the fixing device according to the second aspect, a detection means for detecting the temperature of the cleaning roller is provided, and the blade is based on temperature information from the detection means. It is characterized by further comprising control means for controlling the swinging means so as to swing between the contacted position and the separated position. The invention according to claim 5 is the invention according to claim 1, 2, 3 or 4.
In the cleaning device of the fixing device described above, the blade is made of a heat-resistant resin film, and is in contact with the rotation direction of the cleaning roller in a counter direction.

The invention according to claim 6 is based on claims 1, 2 and
In the cleaning device of the fixing device described in item 3, 4 or 5, a holding layer is provided on the collecting surface of the blade for adhesively holding the scraped deposit.

[0010]

The attached substances such as toner attached to the fixing roller are transferred to the cleaning roller and further to the backup roller. The deposits transferred to the backup roller are
It is transferred to the cleaning roller again, scraped off by a blade and collected.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes an image forming apparatus main body to which the fixing device 50 is applied, and reference numeral 20 denotes an automatic document feeder (hereinafter referred to as an automatic document feeder) which is placed above the image forming apparatus main body 10 and conveys the document D from the stacking position to the reading position. It is called DJF20)
Reference numeral 30 represents a sheet feeding device, respectively.

The image forming apparatus main body 10 is provided with an exposure optical device 40 which is disposed on the upper portion thereof and forms an electrostatic latent image on the photoreceptor 11.
A photoconductor 11 arranged below the photoconductor 11, a charging charger 12 for uniformly charging the photoconductor 11, an eraser 13 for erasing the electric charge of a non-image portion, and a developing device 14 for visualizing an electrostatic latent image. A transfer device 15 that transfers the visible image formed by the developing device 14 onto the transfer paper P and conveys it;
Fixing device 5 for fusing and fixing the toner image transferred by
0, and a cleaning unit 1 for cleaning the photoconductor 11 by removing the toner remaining on the photoconductor 11 after the transfer.
It is mainly composed of 6 and 6.

The exposure optical device 40 includes an illumination lamp 41 for irradiating the document D conveyed by the DJF 20 to the contact glass 21 with light, a scanning mirror 42 for reflecting and reflecting light reflected from the surface of the document D, and a scanning mirror 42. Optical path folding mirror pair 43a, 43 moving at half the speed of
b, imaging lens 43, and folding mirror groups 44a, 44
b and 44c.

The paper feeding device 30 includes a plurality of paper feeding cassettes 31.
The transfer sheet P is sent out from one of them by the paper feed roller 32 to the transport path 33. A pair of registration rollers 34a and 34b is arranged in front of the transfer device 15 on the transport path 33. Reference numeral 39 indicates a manual feed tray.

Behind the fixing device 50, a pair of discharge rollers 3
5, a paper discharge tray 36 is arranged. Paper ejection roller pair 3
Immediately after 5, a path switching member 37 that switches the path of the transfer paper P sent by the paper discharge roller pair 35 is provided. The path switching member 37 transfers the transfer paper P to the paper discharge tray 36.
To a reversing means 38 for reversing the transfer paper P during double-sided copying.

In the fixing device 50, as shown in FIG. 2, a pair of fixing rollers 51 and 52 (hereinafter, the fixing roller 51 is referred to as an upper fixing roller and the fixing roller 52 is referred to as a lower fixing roller) and a transfer sheet P are transferred. Upper fixing roller 51 facing the toner T
A cleaning roller 54 in contact with the cleaning roller 54, a backup roller 55 in contact with the cleaning roller 54, and a blade 56 that abuts the cleaning roller 54 and scrapes off toner T, paper dust, and other adhering matter adhering to the cleaning roller 54.
And a swing means 57 for swinging the blade 56.

The upper fixing roller 51 is formed by coating a core metal 51a made of aluminum or the like with a fluororesin layer 51b made of ethylene tetrafluoride or the like. Inside the upper fixing roller 51,
A heater 53 that heat-melts the toner T is provided, and a thermistor 58 that detects the temperature of the upper fixing roller 51 and an outer peripheral surface of the heater 53 that promotes the releasability of the toner T of the upper fixing roller 51 to prevent abrasion. A release agent applying roller 59 for applying a release agent is provided to prevent the above. The temperature information from the thermistor 58 is input to the control means 60, and the control means 60
Controls energization of the heater 53 to maintain the temperature of the upper fixing roller 51 at a predetermined fixing temperature.

The lower fixing roller 52 is in pressure contact with the upper fixing roller 51, and a rubber layer 52b made of silicon rubber is formed on a core metal 52a such as aluminum.

The cleaning roller 54 is provided on the upstream side of the release agent applying roller 59 with respect to the rotation direction of the upper fixing roller 51, and is brought into pressure contact with the upper fixing roller 51 by a pressing means (not shown). . A thermistor 61 that detects the temperature of the cleaning roller 54 is arranged on the outer peripheral surface of the cleaning roller 54.
The temperature information of 1 is input to the control means 60, and the control means 60 controls the swing position of the blade 56 by the swing means 57.

A power source 62 for applying a bias voltage having a polarity opposite to that of the toner T is connected to the cleaning roller 54. For example, when the toner T has a negative polarity, a negative voltage is applied to the cleaning roller 54 to adhere the toner T to the surface of the cleaning roller 54.

The blade 56 is made of a heat-resistant resin film and has a thickness of about 100 μm. The blade 56 is downstream of the nip portion between the cleaning roller 54 and the backup roller 55 in the rotation direction of the cleaning roller 54 and is the cleaning roller. It is arranged so as to come into contact with the rotation direction of 54 in the counter direction. As shown in FIG. 3, the blade 56 is formed with a holding layer 56a that adheres and holds adhered substances such as the scraped toner T and paper dust.

If a fluorine resin layer of ethylene tetrafluoride or the like is provided on the surface of the blade 56 instead of the holding layer, cleaning during maintenance becomes easy.

The swinging means 57 has an arm 63 having a blade 56 fixed at one end and a pin 64a at the other end of the arm 63.
The solenoid 64 is mainly composed of a solenoid 64 and a spring 65 for urging the arm 63 downward in FIG.

The solenoid 64 is connected to the control means 60, its operation is controlled, and the arm 63 is connected to the shaft 63a.
And the blade 56 is swung between a position in contact with the cleaning roller 54 and a position separated from the cleaning roller 54 (a position indicated by a chain double-dashed line in FIG. 2).

The cleaning roller 54, the backup roller 55, the blade 56, and the swinging means 57 are housed in a case (not shown) so that toner and the like removed from the upper fixing roller 51 will not scatter.

The control means 60 is composed of a microcomputer as its main part, takes in temperature information of the upper fixing roller 51 from the thermistor 58, controls the operation of the heater 53 based on the temperature information, and controls the upper fixing roller 51. Keep the temperature at the specified temperature. Further, the control means 60 fetches the temperature information of the cleaning roller 54 from the thermistor 61 described above, and when the temperature of the cleaning roller 54 is equal to or lower than a predetermined temperature (when the image forming apparatus starts up), the swinging means 57 operates. The blade 56 is controlled to swing to a position in contact with the cleaning roller 54, and to a position separated from the cleaning roller 54 when the toner image is fixed.

The operation of the above configuration will be briefly described below. As shown in FIG. 1, the document D placed with the image surface facing upward on the DJF 20 is sent out from the first lower sheet to the left in FIG.
1 is conveyed to the reading position.

Then, the document D is exposed by the exposure optical device 40.
Image is projected onto the surface of the photoconductor 11 whose surface is uniformly charged by the charging charger 12, and an electrostatic latent image is formed. The electrostatic latent image on the photoconductor 11 is erased by the eraser 13 in the non-image portion, and then toner is attached by the developing device 14 to form a visible image.

On the other hand, one sheet of transfer paper P is fed from one of the paper feed cassette 31 of the paper feed device 30 or one of the manual feed trays, sent out to the conveyance path 33, and the registration roller pair 3 is fed.
4a, 34b. Registration roller pair 34a, 3
4 b sends the transfer paper P to the transfer device 15 at the timing when the visible image on the photoconductor 11 and the transfer paper P coincide with each other in the transfer device 15. The transfer paper P on which the image is transferred by the transfer device 15 is sent to the fixing device 50. As shown in FIG.
The toner T on the transfer paper P has an upper fixing roller 51 and a lower fixing roller 52 which are heated to a predetermined temperature by the control means 60.
Between the paper and the paper, and after being heated and fixed, the paper output tray 36
Is discharged to.

At the time of fixing, the control means 60 controls the solenoid 6
4 is excited, and the arm 63 is swung about the shaft 63a against the biasing force of the spring 65, and the blade 56 is swung to a position separated from the cleaning roller 54. At the end of fixing and at the start-up of the apparatus, the control means 60 demagnetizes the solenoid 64, and the arm 63 by the urging force of the spring 65.
The blade 56 is swung about 3a, and the blade 56 is swung to the position where it abuts on the cleaning roller 54.

When the transfer paper P on which the image has been transferred contacts the upper fixing roller 51, the toner T is offset to the upper fixing roller 51 as shown in FIG. The offset toner T is applied to the upper fixing roller 51 and the cleaning roller 5.
4 is brought to the contact surface. Since a bias voltage having a polarity opposite to that of the toner T is applied to the cleaning roller 54, the toner T is transferred to the cleaning roller 54. Toner T transferred to the cleaning roller 54
Are further transferred to the backup roller 55 and held on the surface thereof.

When the fixing device 50 is sufficiently warmed, the toner T on the backup roller 55 does not reversely transfer to the cleaning roller 54, but when the fixing device 50 is not sufficiently warmed (when the device is started up). .., the toner T on the backup roller 55 is reversely transferred to the cleaning roller 54. The toner T that has undergone the reverse transfer is scraped off by the blade 56 and is held by the holding layer 56.
held in a.

The retaining layer 5 of the blade 56 during maintenance
The toner T held by 6a is peeled off from the blade 56 together with the holding layer 56a and discarded, a new holding layer 56a is attached, and the blade 56 is regenerated.

When a copy is also made on the back surface of the transfer paper P (duplex copy), the transfer paper P is guided to the reversing means 38 by the path switching member 37 and then conveyed again to the registration roller pair 34a, 34b. The same image forming process as described above is repeated.

The toner remaining on the photoconductor 11 is removed and cleaned by the cleaning unit 16 to be prepared for the next image formation.

FIG. 4 shows a modified example. The fixing device 70 shown in this example is different from the fixing device 50 of the embodiment shown in FIGS. 1 to 3 in terms of the cleaning roller 74 and the backup roller 7.
5. The release agent coating roller 79 is arranged on the downstream side of the upper fixing roller 51 in the rotation direction, the blade 76 is horizontally arranged, and the bias voltage is not applied to the cleaning roller 74. In the figure, the swinging means of the blade 76 is omitted in the drawing.

The cleaning roller 74 is composed of a metal cored bar 74a, an elastic layer 74b of conductive carbon-containing Si rubber or the like, and a PFA tube and a release layer 54c of fluororesin outside the elastic layer 74b. There is.

By forming the cleaning roller 74 with the conductive elastic layer 74b, the amount of triboelectricity between the cleaning roller 74 and the upper fixing roller 51 is reduced, and the toner T, paper dust, etc. from the upper fixing roller 51 can be easily obtained. Transfer to the cleaning roller 7. Further, by forming the release layer 54c, the toner T, paper dust, etc. are easily transferred to the backup roller 79. Also, by arranging the blades 76 horizontally,
It is possible to prevent scattering of the scraped toner T and the like.

[0039]

According to the first aspect of the invention, the adhered substances such as toner adhered to the fixing roller are transferred to the cleaning roller, further transferred to the backup roller, transferred to the cleaning roller again, and scratched by the blade. Since the toner is taken and collected, the reverse transfer of the toner can be prevented.

According to the second aspect of the invention, since the blade is swung, the durability of the blade is improved.

According to the third aspect of the invention, the control means moves the blade to the position where it abuts when the image forming apparatus is started up,
Since the toner image is oscillated to a separated position when the toner image is fixed, it is possible to prevent the reverse transfer of the toner from the backup roller, which occurs remarkably when the image forming apparatus starts up.

According to the fourth aspect of the present invention, the control means swings the blade between the contacted position and the separated position based on the temperature information from the detection means. The reverse transfer of the toner can be prevented.

According to the fifth aspect of the present invention, since the blade is made of a heat-resistant resin film and is brought into contact with the cleaning roller in the counter direction with respect to the rotation direction, the load applied to the cleaning roller is reduced and the apparatus is reduced. Durability is improved.

According to the invention described in claim 6, since the holding layer for adhering and holding the scraped collected matter is provided on the collecting surface of the blade, the collected matter is less likely to fall off and the blade can be easily cleaned. Become.

[Brief description of drawings]

FIG. 1 is a schematic side view of a cleaning device of a fixing device according to an exemplary embodiment of the present invention.

FIG. 2 is an enlarged side view of the fixing device shown in FIG.

FIG. 3 is a diagram showing toner transfer of the fixing device shown in FIG.

FIG. 4 is a side view of a main part of a cleaning device of a fixing device showing a modified example of the invention.

[Explanation of symbols]

 11 Photoreceptor 12 Charging Charger 13 Eraser 14 Developing Device 15 Transfer Device 16 Cleaning Unit 21 Contact Glass 30 Paper Feeding Device 40 Exposure Device 50 Fixing Device 51, 52 Fixing Roller Pair 53 Heater 54 Cleaning Roller 55 Backup Roller 56 Blade 57 Swinging Means 58 Thermistor 59 Release Agent Coating Roller 60 Control Unit

Claims (6)

[Claims] 1. A cleaning device for a fixing device used in an image forming apparatus, comprising: a cleaning roller in contact with at least a fixing roller facing a toner bearing surface of a fixing roller pair for fixing a toner image on a transfer paper; In a cleaning device of a fixing device having a backup roller in contact with the
A cleaning device for a fixing device, which is provided with a blade for collecting. 2. The cleaning device for a fixing device according to claim 1, further comprising a swinging means for swinging the blade between a position in contact with the cleaning roller and a position separated from the cleaning roller. A cleaning device for the fixing device. 3. The cleaning device for a fixing device according to claim 2, wherein the blade is swung to the position where it abuts when the image forming device rises, and to the position where it separates when fixing the toner image. A fixing device cleaning device having control means for controlling the swinging means as described above. 4. The cleaning device for a fixing device according to claim 2, further comprising a detection means for detecting the temperature of the cleaning roller, wherein the blade is brought into contact with the position based on temperature information from the detection means. A cleaning device for a fixing device, comprising: a control unit that controls the swinging unit so as to swing to the separated position. 5. The cleaning device for a fixing device according to claim 1, 2, 3 or 4, wherein the blade is made of a heat-resistant resin film and is abutted in a counter direction with respect to a rotation direction of the cleaning roller. A fixing device cleaning device characterized in that 6. The cleaning device for a fixing device according to claim 1, 2, 3, 4, or 5, wherein a holding layer for adhering and holding the scraped adhering material is provided on the collecting surface of the blade. Fixing device cleaning device.