JP2949686B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In an image forming apparatus, a transfer material (for example, paper or O
It is necessary to fix an unfixed image formed on an HP sheet or the like on the transfer material. A fixing device for this purpose is generally of the heat roll fixing type.

FIG. 4 shows an example of a fixing device of a heat roll fixing type. In this fixing device, a transfer material P carrying an unfixed toner image T includes a fixing roller 10 having heating sources 10c and 11d and a pressure roller 11 The toner image T on the transfer material P is transported by the fixing pressure rollers 10 and 11.
Is heated and pressed to be fixed.

In this case, since the toner on the transfer material P is slightly offset to the fixing roller 10, the fixing roller 10
Is provided with a cleaning device for cleaning the toner offset on the outer surface of the fixing roller 10.

There are various types of cleaning devices. For example, the cleaning device 100 shown in FIG.
Is a fibrous member (for example, Nomex fiber (trade name))
The cleaning web 101 is pressed against the fixing roller 10, and the toner on the fixing roller 10 is adsorbed between the fibers of the cleaning web 101.
0 is to be cleaned. In this case, the cleaning web 101 is gradually taken up by the take-up roller 101, and a new cleaning web 101 is pressed against the fixing roller 10.

There is also a cleaning device in which a cleaning roller made of a metal (for example, aluminum) having a high affinity for toner is brought into contact with the fixing roller 10 and the fixing roller 10 is cleaned by the cleaning roller. JP-A-48-62435).

Further, there has been proposed a device in which a member such as a metal having a high affinity for toner is attached to a fibrous member such as the cleaning web 101.

[0008]

However, in the cleaning device 100 using the cleaning web 101, the surface of the fixing roller 10 becomes rough due to long-term use, and the toner adheres to the fixing roller 10 in a fixed state. If this is the case, there is a problem in that the offset toner on the fixing roller 10 cannot be sufficiently cleaned using the cleaning web 101.

In a cleaning device using a cleaning roller, the surface of the cleaning roller is smooth and hard, so that the offset toner adsorbed on the cleaning roller from the fixing roller 10 is fixed to the surface of the cleaning roller. Become. As a result, as the toner is attracted to the surface of the cleaning roller, the cleaning roller comes into contact with the fixing roller 10 only in a portion where the amount of toner adhered increases, and the cleaning roller cannot be cleaned in the longitudinal direction of the fixing roller 10. There is an inconvenience that a portion is generated.

Further, in a cleaning apparatus in which a metal or the like having a high affinity for toner is attached to a fibrous member similar to the cleaning web 101, the cleaning ability of the toner from the fixing roller 10 is good, Since the toner that has moved to the shape member side is pressed again to the fixing roller 10 side, there is an inconvenience that part of the toner adheres to the fixing roller 10 again.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to effectively clean a developer offset to a roller used for fixing and to remove a developer removed from the roller. The purpose of the present invention is to provide a fixing device that does not cause the toner to adhere to the roller again.

[0012]

In order to achieve the above object, the present invention has a roller for fixing an unfixed image on a transfer material, and a developer offset on the outer surface of the roller has a fibrous form. In a fixing device that is cleaned by a cleaning member, cleaning particles having a high affinity for a developer made of metal, resin, rubber, or the like have an adhesive effect at normal temperature on at least the side of the cleaning member that contacts the roller, but are heated and fixed by the roller. It is characterized in that it is bonded with an adhesive having no bonding effect near the temperature.

[0013]

When the roller to which the offset developer is adhered is cleaned by the cleaning member to which the cleaning particles are adhered, since the developer and the cleaning particles have a high affinity, the developer adheres to the cleaning particles. It is effectively cleaned.

On the other hand, since the roller is heated to the fixing temperature, the cleaning member is also heated to near the fixing temperature. Therefore, the adhesive effect of the adhesive is lost, and the cleaning particles to which the developer has adhered are separated from the cleaning member. Therefore, when the cleaning particles to which the developer adheres are pressed against the roller by the cleaning member, the cleaning particles are not pressed again by the roller, and the cleaning particles do not cause the developer to adhere to the roller again.

[0015]

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

First, a first embodiment of the present invention will be described with reference to FIGS.
This will be described below.

FIG. 1 is a sectional view showing a main part of the fixing device 1. In the drawing, reference numeral 10 denotes a fixing roller, which is an LTV silicon rubber (low-temperature vulcanization type silicon rubber) 10b on an outer layer of an aluminum core 10a. To a predetermined thickness. A pressure roller 11 is provided under the fixing 10 in pressure contact. The outer surface of an aluminum cored bar 11a is coated with an HTV silicon rubber 11b to a predetermined thickness. The layer is provided with a resin coating 11c.

The fixing roller 10 and the pressure roller 11 have halogen heaters 10c, 1
1d is provided. A thermistor 12 is brought into contact with the pressure roller 11, and the thermistor 12 turns on or off the supply of current to the halogen heaters 10c and 11d.
F is controlled. In this manner, the temperature of the fixing roller 10 and the temperature of the pressure roller 11 are maintained at predetermined temperatures (for example, 150 ° C.) appropriate for fixing the unfixed toner image T on the transfer material P on the transfer material P. It is supposed to be. The fixing roller 10 and the pressure roller 11 are rotated in a direction indicated by an arrow b in FIG.

On the other hand, in order to improve the releasability of the toner from the fixing roller 10, a release agent coating device 13 is provided at a predetermined position of the fixing roller 10. The release agent applying device 13 is configured to apply the silicone oil 13a in the oil tank to the fixing roller 10 via the felt 13b.

That is, the transfer material P carrying the unfixed toner image T is conveyed by a device (not shown) in the direction of arrow a in FIG. 1 and rotated in the direction of arrow b in FIG. 1 by a drive device (not shown). Between the fixing roller 10 and the pressure roller 11, and from the halogen heaters 10 c and 11 d to the fixing roller 10.
The unfixed toner image T carried on the transfer material P is fixed on the transfer material P by heat controlled to a predetermined temperature and supplied via the pressure roller 11.

Since the toner on the transfer material P is slightly offset from the outer peripheral surface of the fixing roller 10, a cleaning device 20 is provided to clean the offset toner. Hereinafter, the cleaning device 20 having a characteristic configuration of the present invention will be described.

The cleaning device 20 includes a cleaning web 21 which is a belt-like fibrous cleaning member made of Nomex (trade name) and the like, and presses the cleaning web 21 against the fixing roller 10 to remove the offset toner on the fixing roller 10. A pressing roller 22 for cleaning with the cleaning web 21, a winding roller 23 for gradually winding the used cleaning web 21 having a reduced cleaning ability, an unwind roller 24 for gradually feeding out a new cleaning web 21, and the like. It is composed of

As shown in FIG. 2, nickel particles 21b, which are cleaning particles having a high affinity for the toner, are adhered to the cleaning web 21 between the web fibers 21a via an adhesive. The adhesive in this case has an adhesive effect at room temperature, but the fixing temperature of the toner image T (in this case, 1
In the vicinity of 50 ° C.), it has no adhesive effect, has heat resistance higher than the fixing temperature, and has a fixing roller
Any material may be used as long as it has a higher affinity for the toner than the material.
Specifically, an epoxy adhesive may be used.

The cleaning web 21 (hereinafter, referred to as a nickel-bonded web) is pressed by the fixing roller 10 via the pressing roller 22 at a predetermined speed (for example, a moving speed of 1 mm per 100 transfer materials). 23
And the offset toner on the fixing roller 10 is cleaned.

In this case, the offset toner on the fixing roller 10 is formed by the nickel particles 21b of the nickel bonding web 21.
And the fixing roller 10 is effectively cleaned, but the temperature of the nickel-adhesive web 21 pressed by the fixing roller 10 has risen to the fixing temperature. The attached nickel particles 21b are formed by the web fibers 21 of the nickel bonding web 21.
a, and falls onto the transfer material P via the fixing roller 10.

As described above, most of the nickel particles 21b to which the toner adheres are formed by the nickel bonding web 21.
From the web fibers 21a of the toner, and falls onto the transfer material P below through the fixing roller 10, so that the nickel particles 21 to which toner has adhered through the nickel adhesive web 21
b is not pressed against the fixing roller 10 again, so that the toner moved to the nickel adhesive web 21 side does not adhere to the fixing roller 10 side again. The amount of the nickel particles 21b falling on the transfer material P is very small and does not affect the image on the transfer material P at all.

Thus, since the fixing roller 10 is effectively cleaned by the nickel adhesive web 21, the life until the fixing roller 10 can be used due to the offset of the toner is much longer than when the conventional cleaning device is used. Improved.

According to the durability test, the number of sheets fixed before the fixing roller 10 becomes unusable due to the offset in the conventional cleaning device using the web was 80,000, whereas the nickel bonding web 21 was When the cleaning device 200 of the present invention was used, the number of fixings reached 200,000, and the life of the fixing roller 10 was significantly extended.

The cleaning device 20 of the fixing device 1 according to the present invention is particularly effective in a fixing device in a full-color image forming apparatus.

That is, in forming a full-color image, in order to reproduce a color close to that of an original document, a plurality of toner layers are heated and melted to mix colors. Therefore, it is necessary to use a sharp melt toner having a low softening point. Further, since the plurality of toners constituting the full-color toner have different components, the temperature suitable for fixing each toner on the transfer material P is slightly different from each other due to a difference in softening point and the like.

On the other hand, the temperature at which the fixing roller 10 is controlled by the thermistor 12 is a constant temperature (for example, 150 ° C.).
Inevitably, one of the toners is fixed at a temperature deviating from a temperature suitable for fixing. Therefore, the toner fixed at a temperature different from the fixing temperature is likely to be offset on the fixing roller 10 as is well known.

For this reason, the surface material of the fixing roller of the fixing device for forming a full-color image is particularly limited, and Teflon (commercially available) used in a conventional fixing device for a black-and-white image is used from the viewpoint of releasability. It is difficult to use a fluororesin-based material such as (name), and silicon rubber as shown in FIG. 1 is used, and silicon oil is applied thereon. Further, among silicone rubbers, RTV (room temperature vulcanization type silicone rubber) is particularly preferable.

In such a combination of the color toner and the fixing roller 10 made of silicone rubber, not only the adhesion between the color toner and silicone rubber is high, but also the toner melted by heat enters the silicone rubber, The rubber surface layer of the fixing roller 10 is deteriorated, so that the releasability of the fixing roller 10 is deteriorated.

As described above, the color toner used in the color image forming apparatus is easily offset to the fixing roller of the fixing device, and the material of the fixing roller used in this case is also easy to offset the toner. The fixing device 1 according to the present invention is very effective as a fixing device for a color image forming apparatus.

When a durability test was conducted using the fixing device 1 shown in FIG. 1, the number of sheets fixed until the fixing roller 10 became unusable due to offset was 8,000 sheets in a conventional cleaning device using a web made of Nomex. On the other hand, in the cleaning device 20 of the present invention using the nickel bonding web 21,
The number of sheets reached 10,000, and the life of the fixing roller 10 was greatly extended.

Next, a second embodiment of the present invention will be described.
Components having the same functions as those according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

On the cleaning web 21 of the cleaning device 20 of the fixing device 1 according to the present embodiment, nickel particles 21b having a strong affinity for toner were adhered to the web fibers 21a as cleaning particles in two steps.

First, in the first stage, the nickel particles 2 are formed of a polyester-based adhesive whose adhesive effect does not change with temperature.
1b is adhered to the web fibers 21a of the cleaning web 21 on the fixing roller 10 side, and then the nickel particles 21b are placed in the same place as above using an epoxy-based adhesive having an adhesive effect at room temperature but not having an adhesive effect near the fixing temperature. Was adhered to.

Thus, the toner offset to the fixing roller 10 adheres to the nickel particles 21b which are partly detached and detaches from the cleaning web 21, so that the same effect as in the first embodiment can be obtained. Since the offset toner on 10 adheres to the nickel particles 21b which do not separate, the cleaning effect can be further improved.

When the durability test of the fixing roller 10 was performed using the cleaning device 20 having the above configuration, the fixing roller 10 used in the fixing device of the normal image forming apparatus for forming a black and white image has a fixed number of 250,000. The fixing roller 10 used in the fixing device of the color image forming apparatus has a durability life of 70,000 sheets.

Next, a third embodiment of the present invention will be described with reference to FIG. Components having the same functions as those according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the cleaning web 21 of the cleaning device 20 of the fixing device 1 according to the present embodiment, aluminum particles having a strong affinity for toner are used as cleaning particles as web fibers 21a in the same manner as in the first or second embodiment. Adhered to. Further, a collecting device 30 for collecting the aluminum particles to which the toner has adhered is provided downstream of the cleaning device 20 in the rotation direction of the fixing roller 10.

The collecting device 30 contacts the fixing roller 10 and rotates the magnetic roller 31 in the counter direction with respect to the rotation direction of the fixing roller 10, and removes the aluminum particles adsorbed around the magnetic roller 31 from the magnetic roller 31. It comprises a blade 32 for scraping off and a collecting pan 33 for accommodating the aluminum particles scraped off by the blade 32.

The cleaning web 21 of the cleaning device 20 is moved by the pressing roller 22 to the fixing roller 10.
, The offset toner on the fixing roller 10 adheres to the aluminum particles of the cleaning web 21, thereby effectively cleaning the fixing roller 10. The aluminum particles to which the toner detached from the web fibers 21a adheres move on the fixing roller 10, and are attracted and collected by the magnetic roller 31 of the collecting device 30.

The aluminum particles on the magnetic roller 31 are collected in a collecting pan 33 via a blade 32.

As described above, in this embodiment, since the aluminum particles to which the toner adheres are collected by the collecting device 30, the aluminum particles do not scatter to the transfer material P or the like, and the operating environment of the fixing device 1 is improved. Is done.

In the first to third embodiments, the nickel particles 21 having a high affinity for the toner are used as the cleaning particles.
b and aluminum particles were used, but it is not necessary to be limited to this.
Of course, other metal particles may be used as long as they have a high affinity for the toner. In addition, if the affinity for the toner is greater than the material of the fixing roller 10, the cleaning particles may be resin or rubber particles.

[0048]

As is apparent from the above description, according to the present invention, cleaning particles having a high affinity for the developer are cleaned with an adhesive having an adhesive effect at room temperature but not having an adhesive effect near the fixing temperature. Since it is adhered to the member, the cleaning member can achieve effective cleaning of the roller via the cleaning particles,
Since the cleaning particles to which the offset developer has adhered from the roller are separated from the cleaning member, the offset developer does not adhere to the roller again via the cleaning member.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a fixing device according to a first embodiment.

FIG. 2 is an enlarged view of a cleaning web of the cleaning device.

FIG. 3 is a sectional view of a main part of a fixing device according to a third embodiment.

FIG. 4 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 Reference Signs List 10 fixing roller (roller) 21 cleaning web (cleaning member) 21b nickel particles (cleaning particles) P transfer material T toner image (unfixed developed image)

Claims (3)

(57) [Claims] An image forming apparatus for fixing an unfixed image on a transfer material.
A roller having a roller and offset to the outer surface of the roller
The image agent is cleaned by a fibrous cleaning member.
In the fixing device is made of a metal, a resin, rubber or the like
Cleaning particles with a high affinity for the developer
At room temperature, at least on the side of the
Although it has an adhesive effect, it does not
A fixing device, wherein the fixing device is bonded with an adhesive having no bonding effect . 2. The method according to claim 1, wherein a part of said cleaning particles is fixed at a fixing temperature.
Adhesive that has an adhesive effect even in the vicinity of the cleaning member
The fixing device according to claim 1, wherein the fixing device is adhered . 3. A cleaning member, comprising:
Recovery device that collects cleaning particles detached to the roller side
The fixing device according to claim 1 or 2, characterized in that the provided.