JPH04261572A - Fixing device - Google Patents

Abstract

PURPOSE:To effectively perform cleaning to remove toner which is offset to the fixing roller of a fixing device and to prevent toner removed from the fixing roller from adhering to the fixing roller side again. CONSTITUTION:Nickel particles 21b having large affinity to the toner are attached to a cleaning web 21 for cleaning the fixing roller 10 with adhesive. This adhesive has such a property that an adhesive effect is achieved at an ordinary temperature but is not achieved near a fixing temperature. Therefore, effective cleaning is performed through the nickel particles 21b, and the nickel particles 21b to which the offset toner from the fixing roller 10 adheres are separated from the cleaning web 21 in the case of cleaning, so that the offset toner is prevented from adhering to the fixing roller 10 again.

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 image forming apparatuses such as copying machines, laser beam printers, and magnetic stylus printers.

0002

2. Description of the Related Art Image forming apparatuses use a transfer material (for example, paper or
It is necessary to fix the unfixed image formed on the transfer material (HP sheet, etc.) onto the transfer material. A fixing device for this purpose generally uses a heat roll fixing method.

FIG. 4 shows an example of a heat roll fixing type fixing device. In this fixing device, a transfer material P carrying an unfixed toner image T is transferred to a fixing roller 10 having heat sources 10c and 11d and a pressure roller 11. The toner image T on the transfer material P is conveyed to the pressure contact part with the transfer material P by the fixing pressure rollers 10 and 11.
is heated and pressurized to fix it.

In this case, since the toner on the transfer material P is slightly offset to the fixing roller 10, the fixing roller 10
A cleaning device is provided for cleaning off-set toner on the outer surface of the fixing roller 10.

[0005] There are various types of cleaning devices, but for example, a cleaning device 100 shown in FIG. , the toner on the fixing roller 10 is adsorbed between the fibers of the cleaning web 101, and the fixing roller 10 is
It is for cleaning. In this case, the cleaning web 101 is gradually wound up toward the take-up roller 101, and a new cleaning web 101 is brought into pressure contact with the fixing roller 10.

There is also a cleaning device in which a cleaning roller made of a metal (for example, aluminum) that has a high affinity with toner is brought into contact with the fixing roller 10, and the fixing roller 10 is cleaned by this cleaning roller. Publication No. 48-62435).

Furthermore, it has been proposed that a fibrous member such as the cleaning web 101 is attached with a member such as metal that has a high affinity with toner.

[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 toner adheres to the fixing roller 10 in a fixed state. If this happens, there is a problem that the offset toner on the fixing roller 10 cannot be sufficiently cleaned using the cleaning web 101.

Furthermore, in a cleaning device using a cleaning roller, since the surface of the cleaning roller is smooth and hard, the offset toner adsorbed from the fixing roller 10 to the cleaning roller may stick to some places on the surface of the cleaning roller. Become. As a result, as toner is adsorbed to the surface of the cleaning roller, the cleaning roller comes into contact with the fixing roller 10 only in areas where more toner is stuck, and the cleaning roller cannot clean the fixing roller 10 in the longitudinal direction. This causes an inconvenience in that some spots are generated.

Furthermore, in a cleaning device in which a fibrous member similar to the cleaning web 101 is attached with a metal or the like that has a high affinity for toner, the cleaning ability of the toner from the fixing roller 10 is good, but the toner is removed from the fibers through the metal or the like. Since the toner that has moved toward the shaped member is pressed again toward the fixing roller 10, there is an inconvenience that some of the toner ends up adhering to the fixing roller 10 again.

The present invention has been made in view of the above problems, and its purpose is to effectively clean the developer offset to the roller used for fixing, and to clean the developer removed from the roller. To provide a fixing device that does not cause the liquid to adhere to the roller side again.

0012

[Means for Solving the Problems] In order to achieve the above object, the present invention has a roller for fixing an unfixed image on a transfer material, and the developer offset on the outer surface of the roller is fibrous. In a fixing device that is cleaned by a cleaning member, cleaning particles made of metal, resin, rubber, etc. that have a high affinity with the developer are applied to at least the side of the cleaning member that comes into contact with the roller. It is characterized in that it is bonded with an adhesive that has no adhesive effect near temperatures.

[0013]

[Operation] When cleaning the roller to which offset developer has adhered using the cleaning member to which cleaning particles are adhered, since the developer and cleaning particles have a high affinity, the developer adheres to the cleaning particles, and this roller Cleaned effectively.

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 is attached are separated from the cleaning member. Therefore, the cleaning particles to which the developer has adhered are not pressed against the roller again when the cleaning member presses the roller, and the developer does not adhere to the roller again from the cleaning particles.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First, a first embodiment of the present invention is shown in FIGS. 1 and 2.
This is explained by:

FIG. 1 is a sectional view showing the main parts of the fixing device 1. In the figure, 10 is a fixing roller, which is made of LTV silicone rubber (low-temperature vulcanization type silicone rubber) 10b on the outer layer of an aluminum core 10a. is coated with a predetermined thickness. A pressure roller 11 is provided in pressure contact with the lower side of this fixing 10, which coats the outer layer of an aluminum core metal 11a with HTV silicone rubber 11b to a predetermined thickness, and further coats the outer layer of an aluminum core 11a with HTV silicone rubber 11b, The layer is coated with a resin coating 11c.

Further, within these fixing roller 10 and pressure roller 11, halogen heaters 10c and 10, which are heat sources, are installed.
1d is arranged. A thermistor 12 is brought into contact with the pressure roller 11, and the thermistor 12 controls ON or OFF of the supply of current to the halogen heaters 10c and 11d. In this way, the fixing roller 1
0 and the temperature of the pressure roller 11 are maintained at predetermined temperatures (for example, 150° C.) suitable for fixing the unfixed toner image T on the transfer material P onto the transfer material P. These fixing roller 10 and pressure roller 11 are rotated in the direction of arrow b in the figure by a device not shown.

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

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

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

The cleaning device 20 includes a cleaning web 21 which is a belt-like fibrous cleaning member made of Nomex (trade name) or the like, and presses the cleaning web 21 against the fixing roller 10 to remove the offset toner on the fixing roller 10. A pressure roller 22 that cleans the cleaning web 21, a take-up roller 23 that gradually winds up the used cleaning web 21 whose cleaning ability has decreased, and an unwinding roller 24 that gradually unwinds a new cleaning web 21. It consists of

As shown in FIG. 2, the cleaning web 21 has nickel particles 21b, which are cleaning particles having a high affinity for toner, bonded between web fibers 21a with 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
It has no adhesive effect near 50°C, has heat resistance higher than the fixing temperature, and
Any material may be used as long as it has a higher affinity with the toner than the other materials. Specifically, epoxy adhesives are considered.

The cleaning web 21 (hereinafter referred to as the nickel bonded web) is pressed against the fixing roller 10 via the pressure roller 22 and moved at a predetermined speed (for example, a moving speed of 1 mm per 100 sheets of transfer material) by the take-up roller. 2
3 to clean the offset toner on the fixing roller 10.

In this case, the offset toner on the fixing roller 10 is offset by the nickel particles 21b of the nickel adhesive web 21.
However, since the temperature of the nickel adhesive web 21 pressed against the fixing roller 10 has risen to the fixing temperature, the adhesion effect of the adhesive is lost and the toner is removed. The attached nickel particles 21b are attached to the web fibers 21 of the nickel adhesive 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 toner is attached are attached to this nickel adhesive web 21.
The nickel particles 21 to which the toner is attached via the nickel adhesive web 21 separate from the web fibers 21a and fall onto the transfer material P below via the fixing roller 10.
b is not pressed against the fixing roller 10 again, and therefore the toner that has moved to the nickel adhesive web 21 side does not adhere to the fixing roller 10 side again. Note that the amount of nickel particles 21b falling onto the transfer material P is very small and does not affect the image on the transfer material P in any way.

Thus, since the fuser roller 10 is effectively cleaned by the nickel adhesive web 21, the lifespan of the fuser roller 10 until it becomes usable due to toner offset is much longer than when a conventional cleaning device is used. improved.

Incidentally, according to a durability test, in a cleaning device using a conventional web, the number of sheets fixed before the fixing roller 10 became unusable due to offset was 80,000 sheets, whereas the number of sheets fixed with the nickel adhesive web 21 was In the cleaning device 200 of the present invention used, the number of sheets fixed as described above reached 200,000 sheets, and the life of the fixing roller 10 could be significantly extended.

Furthermore, 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 full-color image formation, in order to reproduce colors close to those of the original document, multiple layers of toner are heated and melted to mix colors, so it is necessary to use sharp melt toner with a low softening point. Further, since the plurality of toners constituting the full-color toner each have different components, the temperature suitable for each toner to be fixed on the transfer material P is slightly different due to differences in softening points and the like.

On the other hand, the temperature of the fixing roller 10 controlled by the thermistor 12 is a constant temperature (for example, 150° C.).
Therefore, some of the toners will inevitably be fixed at a temperature that deviates from the temperature suitable for fixing. Therefore, as is well known, toner that is fixed at a temperature that deviates from the fixing temperature is likely to be offset onto the fixing roller 10.

[0032] For this reason, the surface material of the fixing roller of the fixing device used in full-color image formation is particularly limited. It is difficult to use fluororesin-based materials such as fluorine rubber, so silicone rubber as shown in Figure 1 is used, and silicone oil is coated on top of it. Furthermore, among silicone rubbers, RTV (room temperature vulcanizable silicone rubber) is particularly preferred.

In such a combination of color toner and the fixing roller 10 made of silicone rubber, not only is the adhesion between the color toner and the silicone rubber high, but also the toner melted by heat can penetrate into the silicone rubber. The rubber surface layer of the fixing roller 10 is changed in quality, thereby deteriorating the mold releasability of the fixing roller 10.

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 also easily causes the toner to offset. The fixing device 1 according to the present invention is very effective as a fixing device for a color image forming apparatus.

When an durability test was conducted using the fixing device 1 shown in FIG. 1, it was found that in a conventional cleaning device using a web made of Nomex, the number of sheets fixed was 8000 before the fixing roller 10 became unusable due to offset. On the other hand, in the cleaning device 20 of the present invention using the nickel adhesive web 21, the number of sheets to be fixed is 5.
The number of sheets reached 10,000,000 sheets, and the life of the fixing roller 10 was significantly extended.

Next, a second embodiment of the present invention will be described. Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In the cleaning web 21 of the cleaning device 20 of the fixing device 1 according to this embodiment, nickel particles 21b having a strong affinity with toner were bonded to the web fibers 21a in two steps as cleaning particles.

First, in the first step, nickel particles 2 are attached using a polyester adhesive whose adhesive effect does not change depending on temperature.
1b to the web fibers 21a of the cleaning web 21 on the side of the fixing roller 10, and then the nickel particles 21b are attached to the same location as above using an epoxy adhesive that has an adhesive effect at room temperature but does not have an adhesive effect near the fixing temperature. It was glued to.

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

A durability test was conducted on the fixing roller 10 using the cleaning device 20 having the above configuration, and it was found that the number of sheets fixed was 250,000 with the fixing roller 10 used in the fixing device of an image forming apparatus for normal black and white image formation. The fixing roller 10 used in the fixing device of a color image forming apparatus had a durable life of 70,000 sheets.

Next, a third embodiment of the present invention will be explained with reference to FIG. Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In the cleaning web 21 of the cleaning device 20 of the fixing device 1 according to this embodiment, aluminum particles having a strong affinity with toner are used as cleaning particles to form web fibers 21a in the same manner as in the first or second embodiment. is glued to. Further, a recovery device 30 for recovering aluminum particles to which toner is attached is provided downstream of the cleaning device 20 in the rotational direction of the fixing roller 10 .

The collection device 30 includes a magnetic roller 31 that comes into contact with the fixing roller 10 and rotates in a counter direction with respect to the rotational direction of the fixing roller 10, and collects aluminum particles attracted around the magnetic roller 31 from the magnetic roller 31. It consists of a scraping blade 32 and a collection pan 33 that accommodates the aluminum particles scraped off by the blade 32.

The cleaning web 21 of the cleaning device 20 is then pressed against the fixing roller 10 by the pressing roller 22.
The offset toner on the fixing roller 10 adheres to the aluminum particles of the cleaning web 21, and the fixing roller 10 is effectively cleaned, and the cleaning web 21 reaches near the fixing temperature. The aluminum particles to which the toner has detached from the web fibers 21a move on the fixing roller 10, are attracted to the magnetic roller 31 of the collecting device 30, and are collected.

The aluminum particles on the magnetic roller 31 are collected into the collection pan 33 via the blade 32.

As described above, in this embodiment, the aluminum particles to which toner is attached are collected by the collecting device 30, so that the aluminum particles are not scattered onto the transfer material P, etc., and the operating environment of the fixing device 1 is improved. be done.

In the first to third embodiments described above, nickel particles 21 having high affinity with toner are used as cleaning particles.
b and aluminum particles were used, but it is not necessary to be limited to these.
Of course, other metal particles may be used as long as they have a high affinity with the toner. It goes without saying that the cleaning particles may be resin or rubber particles as long as they have a greater affinity with the toner than the material of the fixing roller 10 .

[0048]

Effects of the Invention As is clear from the above explanation, according to the present invention, cleaning particles having a high affinity for the developer can be cleaned with an adhesive that has an adhesive effect at room temperature but does not have an adhesive effect near the fixing temperature. Since the roller is adhered to the member, the cleaning member can effectively clean the roller through the cleaning particles, and since the cleaning particles to which the offset developer from the roller has adhered are separated from the cleaning member, the offset developer The agent will not adhere to the roller again via the cleaning member.

[Brief explanation of the drawing]

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

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

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

FIG. 4 is an explanatory diagram of a prior art.

[Explanation of symbols]

10 Fixing roller (roller) 21
Cleaning web (cleaning member) 21b
Nickel particles (cleaning particles) P
Transfer material

Claims (3)

[Claims] 1. A fixing device having a roller for fixing an unfixed image on a transfer material, and in which a developer offset on the outer surface of the roller is cleaned by a fibrous cleaning member, which is made of metal, resin, Cleaning particles made of rubber or the like that have a high affinity with the developer are adhered to at least the side of the cleaning member that contacts the roller with an adhesive that has an adhesive effect at room temperature but does not have an adhesive effect near the heat fixing temperature of the roller. A fixing device characterized by: 2. The fixing device according to claim 1, wherein a portion of the cleaning particles are bonded to the cleaning member using an adhesive that has an adhesive effect even near the fixing temperature. 3. The fixing device according to claim 1, further comprising a recovery device for recovering cleaning particles separated from the cleaning member toward the roller after cleaning.