JPS6321901B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an apparatus for fixing toner images.

In fields that handle toner images such as electrophotography,
As a device for fixing the toner image on the support material, the toner image support material is sandwiched and conveyed by a pair of rollers, at least one of which is heated internally or externally;
For this reason, devices configured to heat and melt the toner and fix it on the support material are often used, but in this case, in order to prevent toner offset and the support material from wrapping around the roller, the above-mentioned device is usually used. It is well known to apply an anti-offset liquid (usually silicone oil) to the fuser roller on the side of the support material against which the toner image surface is pressed.

At that time, if too much liquid is applied, the toner image supporting material will be stained with the liquid, and when the ink is applied to the image supporting material later with a brush, the ink will not adhere well, and the fixing and pressure rollers Slips may occur in between and disturb the toner image. Even if this is not the case, it will be uneconomical as more oil consumption will be wasted than necessary.
Maintenance was troublesome as oil replenishment and oil supply cartridges had to be replaced more frequently. Also,
If the roller is coated with a material such as silicone rubber that has the property of absorbing the anti-offset liquid, if a large amount is applied, the coating will swell, causing problems such as wrinkles in the support material.

Therefore, as a coating material, Fluoropore (product name:
Tetrafluoroethylene resins with fine continuous pores such as (manufactured by Sumitomo Electric Industries, Ltd.) and GORE-TEX (product name: WLGORE & ASSOCIATES, INC.), or fibrous materials such as high fiber density woven fabrics, non-woven fabrics, felts, etc. It is conceivable that the amount of coating may be reduced as much as possible within the necessary range by using , or a combination of the two.

The present invention further improves such a device, reduces the time required for the anti-offset liquid to ooze out onto the surface of the coating member during factory assembly or when replacing the coating device, and reduces the amount of coating when the device is in operation. The main objective is to provide a fixing device that can be controlled as little as possible within the necessary range.

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

FIG. 1 is an explanatory diagram of an embodiment of the present invention. In the figure, 1 is a fixing roller, and a metal hollow pipe 2 is coated with silicone rubber, tetrafluoroethylene resin, etc.
It is made of a thin coating 3 of anti-offset material, and a heater 4 is disposed in the middle, and the peripheral surface is heated by this heater to a temperature (usually 150 to 200° C.) at which the toner can be melted and fixed. 5 is a pressure roller, and a core metal roll 6 is coated with a thick coating 7 of a flexible elastic material that prevents offset, such as silicone rubber.
is applied. The pressure roller 5 is brought into pressure contact with the fixing roller 1, and as shown in the figure, is elastically deformed at the pressure contact portion to form a nip portion that holds the toner image support material. One of the rollers 1 and 2 is rotationally driven by a motor (not shown),
The other roller rotates due to frictional force with the mating roller. That is, the rollers 1 and 5 rotate in the directions of the arrows to nip and convey the toner image supporting paper P at the nip portion. At this time, the toner image T is thermally melted, adheres to the paper P, and is fixed. The toner supporting surface of the paper P is pressed against the fixing roller 1. Note that the paper P is guided by a guide plate 8 and fed into the nip section, and after passing through the nip, the paper P is passed through the nip by pawl-like members 9 and 1 that are lightly abutted against the rollers 1 and 5, respectively.
0, it is reliably separated from the roller.

11 is an offset prevention liquid coating device. This device 11 has a coating member 12 that is brought into contact with the circumferential surface of the roller 1. In the illustrated example, the application member 12 has a rod-shaped body 13 made of a non-fibrous synthetic resin having fine continuous pores with uniform diameters, rather than bubbles as in a sponge.

Such synthetic resin materials have excellent heat resistance, abrasion resistance, and oil resistance, and also have a smooth surface, good slippage, and are flexible and pliable, making it difficult for molten toner to adhere to them. Generally, fluororesins are suitable because of their excellent preventive properties, but among them, the above-mentioned properties are excellent.
Fluorinated ethylene resins are currently the best choice. As mentioned above, tetrafluoroethylene resins having fine continuous pores are sold under trade names such as Fluoropore and GORE-TEX (details on the manufacturing method of this material can be found in Japanese Patent Publication No. 3068/1983). However, it is of course not limited to this, and other fluororesins, vinyl chloride resins, etc. can be used as long as the member 13 is processed to have fine continuous pores.

The fine continuous pore diameters of such synthetic resin materials are very uniform, and the diameter distribution is approximately 100% concentrated in a very narrow area around the average diameter, forming a so-called delta function shape. Note that the longitudinal direction of the rod-shaped body 13 is made to coincide with the longitudinal direction of the roller 1.

Returning to the figure, the side surface of the application member 12, that is, the surface in contact with the outside air, is made of a material such as non-porous tetrafluoroethylene resin fluorine rubber that does not allow the anti-offset liquid to penetrate, or even if it does, the amount per unit volume or unit time is The sealing member is covered with a synthetic resin membrane 14, which has a much lower amount of penetration of the anti-offset liquid than the member 13 and is flexible. The purpose of this film-like body 14 is to prevent the liquid from seeping out from the surface of the member 12 that is in contact with the outside air, increasing the consumption amount, and preventing the amount of liquid applied to the roller 1 from increasing more than necessary. Therefore, the film-like body 14 does not cover the entire surface of the member 13, and the member 13 is exposed at the portion where the member 12 comes into contact with the roller 1 and at the portion where the liquid, which will be described later, is applied. Therefore, the anti-offset liquid that has permeated the member 13 oozes out from the surface and is applied to the roller 1.

The application member 12 is held and fixed to the container 15 at its side surface. Silicone oil 17 is stored in the container 15, and this oil is applied to the member 13.
is applied to the exposed surface of the Oil 17 penetrates member 13 from the exposed surface of member 13. A projection 15' is provided at the top of this container 15.
This projection 15' is slidably fitted into a guide rail 16 fixed to the main body of the fixing device. The sliding direction is the longitudinal direction of the roller 1. Therefore, the coating device 11 can be removed from the fixing device by pulling it out toward the front in the figure, or conversely, it can be inserted along the rail 16 and attached to the fixing device. When the coating device 11 is mounted on the fixing device as described above, the coating member 12 comes into pressure contact with the roller 1 and is elastically deformed, and when the coating device 11 is removed from the fixing device, the elastic deformation is restored.

Now, in a state where the coating device 11 is removed from the fixing device, the coating member 12 is restored from its elastic deformation as described above, and becomes in a state as shown in FIG. 3. In this state, the member 13 is in a relaxed state, and therefore its fine continuous pores are also in a sufficiently open state. Therefore, when silicone oil is poured into the container 15, the oil quickly permeates into the member 13, and the time required for the oil to ooze out onto the surface that contacts the roller 1 is short. Then, the coating device 1
1 is mounted on the fixing device as described above, the applicator member 12 is pressed against the roller 1, and the member 12 is elastically compressed and deformed upward by the reaction force. Accordingly, the container 15 supporting the side surface of the member 12 tightens the belly portion of the member 12 and therefore the belly portion of the member 13. As a result, the fine continuous pores in the belly portion of the member 13 are contracted,
Therefore, the permeability of oil decreases in this area. Therefore, the amount of oil applied to the roller 1 can be well controlled, making it possible to reduce the amount of oil applied as much as possible within the required range.

FIG. 2 is a diagram for explaining another embodiment of the present invention. In the figure, 18 is a coating roller having a coating 20 such as a tetrafluoroethylene resin on the circumferential surface of a roll 19.
It comes into contact with the fixing roller 1 and rotates in the direction of the arrow. The coating member 12 of the coating device 11 is pressed against the coating roller 18, and silicone oil is first applied to the roller 18. and fixing roller 1
Oil is applied to the surface by an application roller 18.

Now, in the apparatus shown in FIG. 2, the application member 12 has a rod-shaped felt 21 that is long in the longitudinal direction of the roller 18. This felt 21 is covered with a synthetic resin membrane 22 having fine continuous pores such as Fluoropore or GORE-TEX, except for the areas where the oil 17 in the container 15 comes into contact and is applied. The oil 17 is first absorbed and held by the felt 21 by capillary action, and then oozes out from the membrane 22 and is applied to the roller 18 with which the membrane 22 is brought into contact. Note that the seal film 14 as described above is provided on the side surface of the film-like body 22 to prevent oil from seeping out in areas other than the portion that contacts the roller 18.
The membrane 14 may not allow oil to penetrate at all, or
As described above, a material whose permeation amount is significantly smaller than that of the membrane 22 even if it permeates is used.

In the apparatus shown in FIG. 2, when the coating device is attached to the fixing device, the coating member 12 is
is elastically compressed and deformed. That is, the member 12 is pressed against the roller 18 and is compressed and deformed upward, and the inner part of the felt 21 is tightened by the action of the container 15 that supports the side surface of the member 12, increasing the fiber density in this part. This reduces the penetration power of silicone oil. Therefore, before installing the applicator in the fixing device, if oil is poured into the container 15, the oil will ooze out within a short time before it comes into contact with the roller 18 of the applicator 12; 11 is installed in the fixing device, the amount of oil applied to the roller 18, and thus to the roller 1, is controlled to be as small as possible within the necessary range.

It is also possible to eliminate the membrane 22 in the devices of FIGS. 2 and 4. However, in that case, the felt 21 comes into direct contact with the roller 18, but in general, felt tends to require a large amount of oil to be applied, and the felt tends to become clogged with toner or paper dust, resulting in uneven application. Better results can be obtained using the above membrane 22. In other words, the fine continuous pores of synthetic resin materials such as Fluoropore are not clogged with toner or paper dust, and the amount of oil applied decreases over time, which is the case when felt is brought into direct contact with a roller. There are no inconveniences or inconveniences such as streaky unevenness of application.

Note that instead of the felt 21, other elastic fibrous materials such as woven fabrics and nonwoven fabrics can also be used.

In addition, the application member shown in Fig. 3 is attached to the fixing device shown in Fig. 2,
On the other hand, the application member shown in FIG. 4 can also be applied to the fixing device shown in FIG.

Furthermore, in the apparatus shown in FIGS. 1 and 2, when the coating device 11 is attached to the fixing device, the coating member 12 is moved from above using the other end of the spring 23 whose one end is fixed to the fixing device main body. It may be pressed elastically.

In addition, when the synthetic resin material having the above-mentioned fine continuous pores is used for the coating member, the continuous pores have an average diameter of
A thickness of 0.1 to 5μ is suitable.

The present invention can also be applied to a so-called pressure fixing device that fixes toner using the pressure generated when an image support material is clamped between a pair of rollers.

In any case, according to the present invention, the time from when the anti-offset liquid is injected with the coating device not attached to the fixing device until it oozes out onto the surface of the coating member can be significantly shortened, so that the coating device can be used at the factory without being attached to the fixing device. This greatly improves work efficiency during assembly and maintenance and inspection, and after the coating device is attached to the fixing device, it is possible to apply as little liquid as possible within the necessary range, so there is no need to worry about stains on the image support material or swelling of the rollers. Inconveniences such as wrinkles in the image supporting material can also be prevented.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of an embodiment of the present invention, and FIGS. 3 and 4 are explanatory diagrams of essential parts thereof. 1 is a fixing roller, 11 is a coating device, 12 is a coating member, 15 is a container, and 16 is a guide rail.

Claims (1)

[Scope of Claims] 1. A toner image fixing device having a rotating body to which an anti-offset liquid is applied, comprising: a rod-shaped liquid-permeable porous application member; a support member supporting a side surface of the application member; , an offset prevention liquid application means having at least a portion of the side surface of the application member that is in contact with the outside air with a coating that is impermeable to liquid or has a liquid permeability lower than that of the application member; and this offset prevention liquid application means is applied to a fixing device. attachment means for removably supporting the application means, so that when the application means is mounted on the fixing device, the rod-shaped application member is pressed against the rotating body and elastically deformed, and the support member tightens the rod-shaped application member. A fixing device characterized by: 2. The fixing device according to claim 1, wherein the application member is a synthetic resin material having fine continuous pores. 3. The fixing device according to claim 1, wherein the application member comprises a liquid absorbing and holding member covered with a synthetic resin film having fine continuous pores. 4. The fixing device according to claim 3, wherein the liquid absorbing and holding member is a fibrous member. 5. The fixing device according to claim 2, 3, or 4, wherein the synthetic resin is a fluororesin having fine continuous pores. 6. The fixing device according to claim 5, wherein the fluororesin is a tetrafluoroethylene resin having fine continuous pores.