JPS58189671A - Fixing roll - Google Patents

Abstract

PURPOSE:To prolong the life of a fixing roll, by providing a coating layer which has parting properties and is swelled with heat-resistive silicone oil having thermal oxidation stability. CONSTITUTION:A heat roll 1 having a parting coating and a press-contacting roll 8 pressed against it are provided, and the external-diameter contraction of the heat roll 1 due to its deterioration is detected by a detection bar 9. Namely, when it deteriorates, the detection bar 9 pressed by a spring 10 comes to a dotted-line position, so the deterioration is detected. Once the deterioration of the heat roll 1 is detected, the roll 1 is dipped in heat-resistive silicone oil 17 in the dipping tank 16 of a reproducing device to be swelled to nearly uniform cylindricity. The reproduced heat roll 1 is taken out of the dipping tank and a swelling agent is diffused sufficiently into the roller. Further, the surface is cleaned or shaped and polished at need.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive paper that is visualized with a developer, printing ink, etc. in an electrophotographic copying machine, printing machine, etc.

The present invention relates to a fixing roller of a heating device that heats and fixes or heats and dries a developed image on a recording material such as a transfer paper.

Conventionally, as a method of supplying an anti-offset agent to the surface of a heated fixing roller, a method of applying an anti-offset liquid such as silicone oil to the surface of the fixing roller is known, but many of these anti-offset liquids are oil-based. Since it adheres to the copying material and contaminates it, it causes problems such as the rough texture of the surface of the copying material after copying and the addition of ink to the sheet of copying material. In addition, without applying Offset Prevention 11 liquid to the surface of the fixing roller, a releasable coating is generally placed on the side of the copying material J2 that is in contact with the heat-adhesive visualization image surface, thereby making it possible to remove the visible image from the copying material. It is said that this method is effective in preventing offset copy material from being wrapped around the roller. However, the anti-offset +L performance of the RTV rubber roller deteriorates over time, and in our experiments, the surface temperature of the rubber roller was set at 180℃.
When used for about 400 hours in the heated state E, the offset prevention ability of the rubber roller deteriorated to the point where it was no longer practical. After another 200-hour experiment in which tens of thousands of sheets were passed, the outer diameter of the silicone rubber roller shrunk and deformed by about 9% of its initial value, making the fixing uniformity of copies 2 to 1 worse.

As described above, fixing rollers having a releasable coating have a short lifespan, and a longer lifespan has been desired.

Let us look at the deterioration of the length of the fixing roll having the releasable coating from the perspective of the loss of heat on heating as shown in FIG.

Figure 1 shows the weight loss (reduction in mass) of the silicone rubber roller, which is a heated roller during copying paper passing, and the weight loss during heating, and the sum of both is the actual silicone rubber roller. When the weight loss of the silicone rubber roller progresses to the shaded area in the figure, the off-cent prevention ability of the roller deteriorates to the point where it cannot be used for practical purposes. Since the data for the paper passing time and the heating time were captured separately, even though the actual silicone rubber roller and weight loss are the sum of both, if the ratio of heating time to paper passing time is different, the state of deterioration of the roller will be different. It is clear that this will happen.

It is believed that this weight loss of the silicone rubber roller roughly corresponds to the deterioration of the silicone rubber, that is, it approximately corresponds to the amount of loss of the mold release agent contained in the mold release coating.

In order to prevent such deterioration and improve the lifespan, the present inventors focused on silicone oil that swells the releasable coating layer, and the purpose of the present invention is to extend the lifespan of the fixing roller. .

Another object of the present invention is to extend the life of the roller and to utilize fixed resources more efficiently.

The present invention is a fixing roller having a releasable coating layer swollen with thermo-oxidatively stable heat-resistant silicone oil, and since the viscosity change and volatilization loss are only slight even when heated, it can be used as a fixing roller. It loses its excellent durability at temperatures of about 200°C or lower, and exhibits long-term mold releasability effects.

Hereinafter, the present invention will be explained in detail.

In FIGS. 2 and 3, 1 is a heat roller having a releasable coating, and 8 is a pressure roller that comes into pressure contact with the heat roller 1.

In the second illustrated example, when the heat roller l deteriorates, the contraction of its outer diameter is detected by the detection/height 9, and when the heat roller l deteriorates, it is pressed by the spring 10 so as to be at the dotted line position. When detection par 9 is 5 at the dotted line, micro switch 1
1 is detected. In the third illustrated example, the heat roller 1 is heated by the heat roller 12, and when the heat roller 1 deteriorates and its outer diameter shrinks, the heat roller 12 lowers and this As the detection member 13
also falls and is detected by the microswitch 14. In addition to relying on gravity, the detection member may be lowered using a suppressing spring 15.

Deterioration of the heat roller 1 is detected as described in I- below. On the other hand, the heat roller 1 is heated with thermo-oxidatively stable heat-resistant silicone oil 17 (
Example: Immerse in KF965 10-5000 c/s silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) (position B). As a result, even a hot roller that has been extremely shrunk and has uneven cylindricity especially near the center A and J due to long-term use will swell to approximately uniform cylindricity.

The regenerated thermal roller is then taken out of the immersion tank (position C), and the swelling regenerant on the surface of the thermal roller is sufficiently diffused into the interior, and if necessary, the silicone oil on the surface is cleaned or leveled. You can also polish it.

To regenerate and reuse the heat roller 1, depending on the reliability from the detection device, the operation may be performed sequentially from A position → B position → C position, or *V or diameter of the heat roller at B position may be performed. When the temperature has recovered to a certain value, the movement from the 8th position to the C position may be performed independently, and the regeneration heat roller may be left waiting at the C position. Further, position A' in FIG. 4 is provided as an attachment/detachment position in the cycle I- of the thermal roller from position A to position B to position C.

In the examples shown in FIGS. 2 and 3, if the heat rollers are used frequently, it is a good idea to increase the number of heat rollers according to the usage conditions and replace them one by one for reuse.

The +ff method for heating rollers with deteriorated release properties is i.
In addition to immersing a deteriorating heat roller in writing agent, it is effective to restore the releasability by leaving the deteriorated heat roller in a high-temperature heating state for a long time without using it. It was confirmed that there was no wrapping around the roller. This is because the main cause of deterioration is low molecular weight particles that contribute to release properties in the silicone thermal roller, or particles that are released from the surface due to heating.
It is believed that this is because the silicon monomer inside the silicon thermal roller can be diffused onto the roller surface by heating the thermal roller to a high temperature. Although the speed of this diffusion depends on the heating temperature, it was confirmed that practical diffusion progressed sufficiently even when left at room temperature.

In addition, experiments have shown that with a certain type of RTV silicone rubber heated roller, copying material is rolled onto the heated roller almost every time. There was no attachment.

Furthermore, by giving the test piece a rest for 10 days, the winding of several thousand recording sheets did not occur.

Therefore, it is possible to prevent deterioration of the releasability of the heat rollers for a long period of time by preparing several deteriorated heat rollers and replacing them as needed while giving them a rest.

Figure 4 shows a heated roller that has been devised to extend its life. 23 is a releasable coating such as silicone rubber, 24 is a roller shaft, which is a hollow metal core with small holes on the surface, 25 is a small hole drilled in the metal core 11, and 26 is a mold release coating such as silicone oil. Offcent Prevention 11 - It is a liquid. By heating the heat roller 1,
The offset #h11 liquid 26 gradually diffuses into the releasable coating 23 through the small holes 25 made in the metal core, and this roller has a performance that can withstand continuous use for a long time.
are doing.

In addition, 23 of 26 of 1 liquid to prevent offset during heating use.
The rate of diffusion into the inside can be varied by changing the 26 types and viscosity, or by adjusting the hole diameter and number of holes 25, and by selecting the appropriate one according to the application. good. Since it is difficult to make adjustments when the conditions of use change frequently, prepare several heated rollers, use the detection device described above to detect the decrease in roller diameter, and replace deteriorated rollers and old rollers. By sequentially replacing and using the roller, the unused roller will rest and the oil will spread from the inside to the surface, and when it is reused, it will be able to completely restore mold release and fixing properties. As explained above, since the present invention has a releasable coating layer swollen with thermo-oxidatively stable heat-resistant silicone oil, large viscosity changes may occur locally when the entire fixing roller swells. The fixing roller can swell almost stably throughout the fixing roller.

Further, the fixing roller according to the present invention shows a rough diagram of loss of silicone oil due to heating even when heated when the paper is not passing, and FIGS. 2 to 4 are diagrams showing respective embodiments of the present invention.

In the figure, ■ is a heat roller, 8 is a pressure roller, and 12 is a heating roller.

□ -F15 (Iwur)

Claims (1)

[Claims] A fixing roller having a releasable coating layer swollen with thermal oxidation stable and heat-resistant silicone oil.