JP2000131990A - Fixing device, cleaning means for the same and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate cleaning of developer soil on a fixing member in a state where a cleaning means is cold at an initial stage, and also, to prevent the recovered developer from peeling off the cleaning means. SOLUTION: The device is provided with a cleaning roller (cleaning means) 34 which comes into contact with a pressure roller (2nd fixing member) 27 which comes in press contact with a fixing roller (1st fixing member) 25 so as to recover toner 28b shifted to the pressure roller 27. A surface treatment for increasing a surface area is applied on the cleaning roller 34. As for the treatment, a sandblasting treatment of roughening the surface, an alumite treatment of forming an oxide film and a treatment of binding particles with resin, etc., are applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device provided in an image forming apparatus in an electrophotographic copying machine, a laser beam printer (hereinafter, LBP), a cleaning unit provided in the fixing device, and a fixing device provided in the fixing device. The present invention relates to an image forming apparatus having the same.

[0002]

2. Description of the Related Art Conventionally, a fixing device of an electrophotographic image forming apparatus such as a copying machine or a laser beam printer usually has a PTF having a high releasability on a metal roller or a heat-resistant film.
A fixing roller formed by forming a layer of E, PFA, etc. is heated by a heater or the like, and the paper is conveyed while pressing the paper between the fixing roller and the pressing roller, and the toner image on the paper is removed. It is configured to fix by heating and melting.

In such a fixing device, it is ideal that all toner images on the paper are fixed on the paper.
Normally, a very small portion of the toner is transferred from the paper to the fixing roller due to temperature or electrostatic factors. Then, the toner transferred to the fixing roller adheres to the next paper. However, the amount of the toner is usually very small, so that the image quality is not deteriorated.

[0004] Further, there is also a toner which is re-transferred to the pressure roller. Normally, since the surface of the fixing roller has higher releasability than the surface of the pressure roller, the toner that has not adhered to the paper is re-transferred and deposited on the surface of the pressure roller. Depending on the temperature environment, a large amount of toner accumulated to a certain extent, paper dust accumulated on the toner, and the like adhere to the surface of the paper in a large amount and significantly contaminate the paper.

Therefore, in order to prevent the above-mentioned problem from occurring, a cloth-like material is conventionally pressed against the surface of the pressure roller,
By contacting a cleaning member such as a cloth-like member or a metal roller, toner or paper powder is attached to the cleaning member side to clean the surface of the pressure roller.

[0006]

However, in the conventional fixing device, when a cleaning member offset from the paper, for example, a cloth member is used, dirt is immediately deposited on the cleaning member.
The cleaning member must be replaced frequently or it must be rolled up so that a clean cloth always hits the pressure roller surface. Further, when a brush roller or the like is used as a cleaning member, dirt is deposited immediately because all dirt can be cleaned, and a mechanism for scraping off dirt on the pressure roller is required. .

On the other hand, in the case of a system in which a member such as a metal roller is brought into contact with a pressure roller as a cleaning means (cleaning roller system), the cleaning roller is not warmed until toner uniformly adheres to the cleaning roller. At this time, problems such as the inability to collect the toner may occur.

[0008] This phenomenon is particularly remarkable when the room temperature is low, and is particularly conspicuous when the cleaning roller is cooled immediately after the main body is started. When a cleaning roller having a smooth surface is used, the collected toner may be peeled off at the interface between the cleaning roller surface and the collected toner.

The present invention solves the above-mentioned problems of the prior art,
A fixing device, a cleaning member, and a fixing device capable of accelerating cleaning of developer stains on a fixing member in a cold state of an initial cleaning unit and preventing peeling of collected developer from the cleaning unit. It is an object to provide an image forming apparatus provided with the device.

[0010]

In order to achieve the above object, the present invention provides a first fixing member and a second fixing member which are pressed against each other, and at least one of the first fixing member and the second fixing member. Heating means for heating one or the other,
A fixing device for thermally fixing the developer image by sandwiching a transfer material carrying an unfixed developer image in a nip formed by the first fixing member and the second fixing member, In a fixing device provided with a cleaning unit that abuts at least one of the first fixing member and the second fixing member and removes a developer transferred onto the fixing member,
A fixing device characterized in that a surface treatment for increasing a surface area is performed on a contact surface of the cleaning unit with the fixing member.

At this time, by increasing the surface area of the contact surface of the cleaning means contacting at least one of the first fixing member and the second fixing member, the developer adhering to the contacting fixing member is cleaned. It is possible to widen the area that adheres to the means. Therefore, in a state where the cleaning unit is cold in printing immediately after the power is turned on at a low temperature, the developer on the fixing member that comes into contact is smoothly transferred to the cleaning unit, and the developer attached to the fixing member is transferred to the transfer material. Can be prevented. Further, the developer collected on the cleaning means does not bite into the concave portion of the unevenness generated by the surface treatment on the contact surface of the cleaning means in a wedge shape and does not separate from the contact surface of the cleaning means.

Further, the surface roughness of the contact surface of the cleaning means is determined by the amount of bite of the cleaning member into at least one of the first fixing member and the second fixing member contacted by the cleaning means. Preferably smaller.

The surface roughness can be numerically compared by, for example, a ten-point average roughness, but it is a matter of course that the comparison may be made by using another index.

Further, as the surface treatment, a contact surface of the cleaning means may be formed in a porous shape.

[0015] The contact surface of the cleaning means may be made of a porous film.

Further, as the surface treatment, the contact surface of the cleaning means may be anodized.

Further, as the surface treatment, a contact surface of the cleaning means may be exposed.

Further, as the surface treatment, particles may be bound to a contact surface of the cleaning means.

Further, as the surface treatment, particles may be bound after exposing the contact surface with the cleaning means.

According to the present invention, there is provided a first fixing member and a second fixing member which press against each other to form a nip portion, and a heating device for heating at least one of the first fixing member and the second fixing member. Means provided in a fixing device for thermally fixing the developer image by sandwiching a transfer material carrying an unfixed developer image in the nip portion, wherein the first fixing member and the second fixing device are provided. In a cleaning unit of a fixing device for removing a developer transferred onto the fixing member by contacting at least one of the members, a surface treatment for increasing a surface area on a contact surface of the cleaning unit with the fixing member. It is characterized by having given.

At this time, by increasing the surface area of the contact surface of the cleaning means that contacts at least one of the first fixing member and the second fixing member, the developer adhering to the contacting fixing member is cleaned. It is possible to widen the area that adheres to the means. Therefore, in a state where the cleaning unit is cold in printing immediately after the power is turned on at a low temperature, the developer on the fixing member that comes into contact is smoothly transferred to the cleaning unit, and the developer attached to the fixing member is transferred to the transfer material. Can be prevented. Further, the developer collected on the cleaning means does not bite into the concave portion of the unevenness generated by the surface treatment on the contact surface of the cleaning means in a wedge shape and does not separate from the contact surface of the cleaning means.

Further, the surface roughness of the contact surface of the cleaning means is determined by the amount of the cleaning member biting into at least one of the first fixing member and the second fixing member contacted by the cleaning means. Preferably smaller.

The surface roughness can be numerically compared by, for example, a ten-point average roughness, but it is natural that the comparison may be performed by using another index.

Further, as the surface treatment, a contact surface of the cleaning means may be formed in a porous shape.

The contact surface of the cleaning means may be made of a porous film.

Further, as the surface treatment, the contact surface of the cleaning means may be anodized.

Further, as the surface treatment, a contact surface of the cleaning means may be exposed.

Further, as the surface treatment, particles may be bound to a contact surface of the cleaning means.

Further, as the surface treatment, particles may be bound after the contact surface with the cleaning means is exposed.

Image forming means for transferring the developer image carried on the image carrier onto the transfer material; fixing means for fixing the unfixed developer image transferred onto the transfer material;
In the image forming apparatus provided with the fixing device, a fixing device according to the present invention may be provided as the fixing unit.

With this arrangement, in a state where the cleaning unit is cooled in the printing immediately after the power is turned on at a low temperature, the developer on the fixing member that comes into contact with the cleaning unit is smoothly transferred to the cleaning unit, and is transferred to the fixing member. Since transfer of the attached developer to the transfer material can be prevented, high-quality image formation can be achieved. Further, the developer collected on the cleaning means does not bite into the concave portion of the unevenness generated by the surface treatment on the contact surface of the cleaning means in a wedge shape and does not separate from the contact surface of the cleaning means. The collected developer does not transfer to the transfer material via the fixing member, so that a high-quality image can be formed.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a schematic configuration of an image forming apparatus of a laser beam printer (hereinafter, referred to as LBP) embodying the present invention.

In FIG. 1, an image forming apparatus includes a photosensitive layer 11b on a conductive support 11a as an image carrier as a member to be charged.
, A charging roller 12 as a charging device connected to a charging power supply 18 for applying an AC voltage superimposed with a DC voltage, an exposure light 13, a developing device 14 connected to a developing power supply 19, and a transfer power supply 20. The main components are a transfer roller 15 as a transfer member, a static elimination needle 24, a cleaner 16, paper transport guides 21 and 22, and a fixing device 17 connected to the image forming apparatus. In this embodiment, the photosensitive drum 11, the charging roller 12, the developing device 14, the transfer roller 15, the static elimination needle 24
And the cleaner 16 constitute an image forming unit.

In the image forming apparatus configured as described above, the photosensitive drum 11 rotates in a fixed direction,
Reference numeral 2 denotes a photosensitive drum 11
The surface of the photosensitive drum 11 is uniformly charged, and then is exposed by exposure light 13 to form an electrostatic latent image on the photosensitive drum 11. The electrostatic latent image is visualized as a toner image as a developer powder by a developing device 14, and the toner image is transferred onto a transfer material 23 conveyed between a photosensitive drum 11 and a transfer roller 15 by a conveyance guide 21. Is transferred to Thereafter, the transfer material 23 is separated from the photosensitive drum 11 by the biasing static elimination needle 24, moves on the transport guide 22, is introduced into the fixing device 17, and the transfer material 23 is heated under pressure by the fixing device 17. Is a permanent image. On the other hand, the waste toner remaining on the photosensitive drum 11 is collected by the cleaner 16.

The fixing device 17 of the image forming apparatus used here
Details of an example of the configuration will be described below. The fixing device 17
It has a configuration as shown in FIG. A transfer material such as paper is conveyed to a fixing roller 25 as a first fixing member,
The fixing roller 25 is made of a core metal 25a made of aluminum, iron, or the like.
Release layer 2 made of fluororesin such as PFA or PTFE on top
5b, and has a heater 26 therein as a heating means. On the other hand, a pressure roller 27 as a second fixing member is pressed against the fixing roller 25 by a pressure unit (not shown) to form a fixing nip N. The pressure roller 27 is formed by forming an elastic layer 27b made of heat-resistant silicon rubber or the like on a core metal 27a made of aluminum or iron, and a release layer 27c made of a fluororesin such as PFA or PTFE.

The transfer material 22 carrying the toner image 28
Is guided by an entrance guide 29 to a nip portion between the fixing roller 25 and the pressure roller 27, the temperature of which is adjusted by the temperature detection element 31, and is fixed by heating and pressing, whereby the toner image 28 is fixed. The transfer material 23 is separated from the fixing roller 25 by the fixing roller separation claw 30 and discharged out of the apparatus. Generally, the entrance guide 29 is made of a resistance control material (10E8 to 10E10Ω) such as PBT, or a guide surface is formed of a metal such as stainless steel, and the resistance control material is used for a contact point with a fixing frame. . This is because, when the entrance guide is formed with an insulator or the like, the guide surface is charged due to the rubbing with the transfer material 23, and adverse effects such as scattering of toner occur. In order to prevent wrinkles from occurring when the transfer material 23 passes through the nip portion, the fixing roller 25 and the pressure roller 27 are provided with an appropriate inverted crown shape in the longitudinal direction, and the entrance guide 29 forms a fixing nip N. It is a common practice to optimize the location of the intrusion.

As shown in FIG. 3, a part of the toner image 28 of the toner image 28 electrostatically offset from the transfer material 23.
a adheres to the fixing roller 25 and is transferred to the pressure roller 25 (toner 28b), and thereafter, is collected from the pressure roller 25 by a cleaning roller 34 as a cleaning unit that comes into contact with the pressure roller 25, and is accumulated. (Toner 28c). In the present embodiment, in order to reduce the offset of the negative polarity toner image 28 to the fixing roller 25, a negative bias 32 is applied to the fixing roller 25, and a self-bias is applied to the pressure roller 27 by the diode 33. Fixing roller 25 surface and pressure roller core 2
A potential difference is created between the electrodes 7a, and the electric field is used.

In this embodiment, the cleaning roller 34
The cored bar 34a is a metal such as aluminum, iron, or copper, and has a roughened surface, a surface treatment, or the like, which has a larger surface area than a smooth cleaning roller. Specifically, as a means for roughening the surface, sandblasting with irregular-shaped abrasive grains, sandblasting with regular (spherical) glass beads, and the like are available. As a surface treatment, there is a method of forming a porous oxide film 34b on the surface by an oxidation treatment such as an alumite treatment. The same effect can be obtained even if the surface of the cleaning roller 34 is exposed by bonding metal oxide particles, conductive particles such as graphite and carbon with a binder resin such as a phenol resin or a fluorine resin. It goes without saying that a similar effect can be obtained by combining the above methods.

As a result, the surface area of the cleaning roller 34 in contact with the pressure roller increases, and the contact area between the cleaning roller 34 and the pressure roller 27 increases. For this reason, the toner adhering to the pressure roller 27 is removed by the cleaning roller 34 in printing immediately after the power is turned on at a low temperature.
The toner 2 on the pressure roller 27 is
8 smoothly transfers onto the cleaning roller 34,
Transfer of the toner adhered to the pressure roller on the paper can be prevented. Further, as shown in FIG. 4, the toner 28 collected on the cleaning roller 34 does not bite into the concave and convex portions on the surface of the cleaning roller 34 in a wedge shape and does not separate from the surface of the cleaning roller 34. By making the surface roughness of the cleaning roller 34 smaller than the amount of the cleaning roller 34 biting into the pressure roller 27, the cleaning roller 34 and the pressure roller 27
And the toner collection efficiency is improved.

As described above, it is possible to provide a cleaning roller of a fixing device capable of accelerating the cleaning of the toner stain on the pressure roller in the initial cold state and preventing the recovered toner from peeling off from the cleaning roller. it can.

In the present embodiment, the cleaning roller is in contact with the pressure roller. However, the cleaning roller may be in contact with the fixing roller to collect the toner transferred on the fixing roller. The same applies to the following embodiments.

(Second Embodiment) In this embodiment, the first
The same laser beam printer as in the embodiment was used. However, the process speed is set to about 100 mm / sec.

The structure of the fixing device is the same as that of the first embodiment.
, And its surface is sandblasted with irregular-shaped abrasive grains. 10 point average surface roughness (Rz) of such a cleaning roller 34
Is 10 μm.

At this time, the toner 28c collected and accumulated on the cleaning roller 34 has an increased surface area, so that the contact area between the pressure roller and the cleaning roller increases, and the toner 28c enters the concave portion on the surface of the cleaning roller 34 and becomes wedge-shaped. Will stick. Therefore, the pressure roller 2
Even if the cleaning roller 34 is cooled in the print immediately after the power is turned on at a low temperature, the toner 28 on the pressure roller 27 is smoothly transferred onto the cleaning roller 34, Transfer of the toner adhered to the pressure roller on the paper can be prevented. Further, as shown in FIG. 4, the toner 28 collected on the cleaning roller 34 does not bite into the concave and convex portions on the surface of the cleaning roller 34 in a wedge shape and does not separate from the surface of the cleaning roller 34.

By using the fixing device according to the present invention, it is possible to promote the cleaning of the toner stain on the pressure roller in the initial cold state and to prevent the collected toner from peeling off from the cleaning roller. It has become possible to provide a cleaning roller.

(Third Embodiment) In this embodiment, the first
The same laser beam printer as in the embodiment was used. However, the process speed is set to about 150 mm / sec.

The structure of the fixing device is the same as that of the first embodiment.
Of which a porous oxide film is formed on the surface by alumite treatment to a thickness of about 50 μm.

At this time, the toner 28c collected and accumulated on the cleaning roller 34 has a large surface area, so that the contact area between the pressure roller and the cleaning roller increases, and the toner 28c enters the concave portion on the surface of the cleaning roller 34, and becomes wedge-shaped. Adhere to the surface. Therefore, the pressure roller 2
Even if the cleaning roller 34 is cooled in the print immediately after the power is turned on at a low temperature, the toner 28 on the pressure roller 27 is smoothly transferred onto the cleaning roller 34, Transfer of the toner adhered to the pressure roller on the paper can be prevented. Further, as shown in FIG. 5, the toner 28 collected on the cleaning roller 34 does not bite into the concave and convex portions on the surface of the cleaning roller 34 in a wedge shape and does not separate from the surface of the cleaning roller 34.

By using the fixing device according to the present invention, it is possible to promote the cleaning of the toner stain on the pressure roller in the initial cold state and prevent the recovered toner from peeling off from the cleaning roller. It has become possible to provide a cleaning roller.

(Fourth Embodiment) In this embodiment, a laser beam printer similar to the first embodiment is used. However, the process speed is about 200 mm / sec.

The configuration of the fixing device is the same as that of the first embodiment, and the cleaning roller 34 is, as shown in FIG.
The core metal 34a is a pure Al roller having a diameter of φ10, the surface of which is subjected to sand blasting with glass beads, and then carbon 36 as particles is bound with a phenol resin 37. At this time, the ten-point average surface roughness of the cleaning roller 34 is 20 μm.

At this time, the toner 28c collected and accumulated on the cleaning roller 34 has a large surface area, so that the contact area between the pressure roller and the cleaning roller increases, and the toner 28c enters the concave portion on the surface of the cleaning roller 34 and becomes wedge-shaped. Will stick. Therefore, the pressure roller 2
Even if the cleaning roller 34 is cooled in the print immediately after the power is turned on at a low temperature, the toner 28 on the pressure roller 27 is smoothly transferred onto the cleaning roller 34, Transfer of the toner adhered to the pressure roller on the paper can be prevented. Further, the toner 28 collected on the cleaning roller 34 does not bite into the concave and convex portions on the surface of the cleaning roller 34 in a wedge shape and does not separate from the surface of the cleaning roller 34.

By using the fixing device according to the present invention, it is possible to promote the cleaning of the toner stains on the pressure roller in the initial cold state and to prevent the collected toner from peeling off from the cleaning roller. It has become possible to provide a cleaning roller.

[0054]

As described above, according to the present invention,
By increasing the surface area of the contact surface of the cleaning unit that contacts at least one of the first fixing member and the second fixing member, the area where the developer attached to the contacting fixing member adheres to the cleaning unit is increased. Can be expanded. Therefore, in a state where the cleaning unit is cold in printing immediately after the power is turned on at a low temperature, the developer on the fixing member that comes into contact is smoothly transferred to the cleaning unit, and the developer attached to the fixing member is transferred to the transfer material. Can be prevented. Further, the developer collected on the cleaning means does not bite into the concave portion of the unevenness generated by the surface treatment on the contact surface of the cleaning means in a wedge shape and does not separate from the contact surface of the cleaning means.

As described above, there is provided a fixing device and a cleaning member which can promote the cleaning of the developer stain on the fixing member in the initial cold state and prevent the collected developer from peeling off from the cleaning means. It became possible to do.

Further, by providing such a fixing device in the image forming apparatus, it is possible to form a high-quality image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an LBP used in the present embodiment.

FIG. 2 is a fixing device used in the first embodiment.

FIG. 3 is a diagram illustrating a first embodiment.

FIG. 4 is a diagram illustrating a state of toner collected by a cleaning roller according to the first embodiment.

FIG. 5 is a diagram illustrating a state of toner collected by a cleaning roller according to a third embodiment.

FIG. 6 is a diagram illustrating a cleaning roller according to a fourth embodiment.

[Explanation of symbols]

 17 Fixing Device 23 Transfer Material 25 Fixing Roller 27 Pressure Roller 28 Toner Image 34 Cleaning Roller

Claims (17)

[Claims] A first fixing member and a second fixing member that are in pressure contact with each other, and heating means for heating at least one of the first fixing member and the second fixing member. A fixing device for thermally fixing the developer image by sandwiching a transfer material carrying an unfixed developer image in a nip formed by one fixing member and a second fixing member, In a fixing device provided with a cleaning unit that removes the developer transferred onto the fixing member by contacting at least one of the attaching member and the second fixing member, a contact surface of the cleaning unit with the fixing member includes: A fixing device, which has been subjected to a surface treatment for increasing a surface area. 2. The cleaning device according to claim 1, wherein the surface roughness of the contact surface of the cleaning unit is at least one of the first fixing member and the second fixing member contacted by the cleaning unit.
2. The fixing device according to claim 1, wherein the fixing member is smaller than a biting amount of the cleaning member. 3. The fixing device according to claim 1, wherein the contact surface of the cleaning unit is formed in a porous shape as the surface treatment. 4. The fixing device according to claim 3, wherein a contact surface of said cleaning means is made of a porous film. 5. The fixing device according to claim 1, wherein the contacting surface of the cleaning unit is alumite-treated as the surface treatment. 6. The fixing device according to claim 1, wherein a contact surface of the cleaning unit is exposed as the surface treatment. 7. The fixing device according to claim 1, wherein, as the surface treatment, particles are bound to a contact surface of the cleaning unit. 8. The fixing device according to claim 1, wherein as the surface treatment, particles are bound after exposing a contact surface with the cleaning unit. 9. A first fixing member and a second fixing member which press against each other to form a nip portion, and heating means for heating at least one of the first fixing member and the second fixing member. A fixing device that thermally fixes the developer image by sandwiching a transfer material carrying an unfixed developer image in the nip portion, wherein the first fixing member and the second fixing member In a cleaning unit of a fixing device for removing a developer transferred onto the fixing member by contacting at least one of the fixing members, a surface treatment for increasing a surface area is performed on a contact surface of the cleaning unit with the fixing member. Cleaning means for a fixing device. 10. The surface roughness of the contact surface of the cleaning unit is determined by the amount of the cleaning member biting into at least one of the first fixing member and the second fixing member contacted by the cleaning unit. The cleaning unit of a fixing device according to claim 9, wherein the cleaning unit is smaller than the cleaning unit. 11. The cleaning device of a fixing device according to claim 9, wherein the contact surface of the cleaning device is formed as a porous surface as the surface treatment. 12. The cleaning device for a fixing device according to claim 11, wherein a contact surface of said cleaning device is formed of a porous film. 13. The cleaning device for a fixing device according to claim 9, wherein the contact surface of the cleaning device is anodized as the surface treatment. 14. The cleaning device for a fixing device according to claim 9, wherein the contact surface of the cleaning device is exposed as the surface treatment. 15. The cleaning unit of a fixing device according to claim 9, wherein, as the surface treatment, particles are bonded to a contact surface of the cleaning unit. 16. The cleaning device for a fixing device according to claim 9, wherein, as the surface treatment, particles are bound after exposing a contact surface with the cleaning device. 17. An image forming means for transferring a developer image carried on an image carrier onto a transfer material, and a fixing means for fixing an unfixed developer image transferred onto the transfer material. An image forming apparatus comprising: the fixing device according to claim 1 as the fixing unit.