JP2006350118A - Fixing unit roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing unit roller having a silicone sponge elastic body to prevent the generation of benzene from a thermal fixing apparatus for a copier, a printer and a facsimile, etc., by using silicone sponge rubber free from the generation of volatile organic compound such as benzene, whereby, preventing the environment from becoming worse. <P>SOLUTION: The fixing unit roller has at least one elastic silicone sponge layer formed on the periphery of a core bar, regarding the elastic silicone sponge layer, dispersion accelerator not containing a phenyl group is used as dispersion accelerator for filler, and also, silicone sponge obtained by curing and foaming thermosetting silicone rubber composite using diorganopolysilixane not containing a phenyl group as base polymer is used for the elastic layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a roller for a fixing unit used in an image forming apparatus such as a copying machine, a printer, and a facsimile using an electrophotographic system.

  In order to save energy, recently, a roller for a fixing unit of a heat fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or the like has been developed by using a thin hollow core metal roll having a heater therein. A system is adopted in which the rise time of the equipment is shortened by further reducing the wall thickness.

  In addition, a thin fixing belt made of heat-resistant resin such as polyimide resin or metal was created, and this was made into a roll and provided with a release layer such as fluororesin on the surface and heated from the inside with a heater. A fuser roller is also used.

  These methods have an advantage that the rise time of the apparatus can be shortened because a thin cored bar or a thin fixing belt having a small heat capacity is used. However, for quick start-up of the device, it is preferable that the pressure roller of the fixing device further removes heat from the fixing roll and the fixing belt as much as possible during heat fixing. A low thermal conductivity pressure roller is used in which a silicone sponge layer having a low thermal conductivity is formed on the surface of the pressure roller and a thin fluororesin layer is provided on the outer surface thereof.

  Instead of such a fixing device roller, the same thin fixing belt as described above is run using, for example, a driving roller arranged in an inverted triangular triangle, and is similarly heated and fixed using a separate heating device. Has also been done. In this case, both the driving roller for running the thin fixing belt and the pressure roller used therefor are provided with a low thermal conductive silicone sponge layer on the surface layer to form a low thermal conductive fixing roller. It has been broken.

  Various methods for forming a silicone sponge layer on such a fixing roller are known as follows. (a) A thermosetting silicone rubber composition containing a vulcanizing agent, a foaming agent, etc. is continuously extruded, heated by passing through a hot air vulcanizer, and foamed and vulcanized to form a silicone sponge tube. A method of creating and coating the cored bar, (b) coating the core metal peripheral surface with a thermosetting silicone rubber composition containing a vulcanizing agent and a foaming agent, and heating the cored bar together with the cored bar By performing foaming and vulcanization, the silicone sponge layer is formed at the same time as the foaming and vulcanization, and (c) a method of forming the silicone sponge layer by the gas generated during the curing reaction of the liquid silicone rubber, A method of forming a silicone sponge layer by blending a foaming agent with silicone rubber, or a method of combining these, (d) Low specific gravity by blending a hollow balloon such as a resin balloon or glass balloon with silicone rubber How to form the silicone sponge layer, and the like. Among these, silicone sponges using thermosetting silicone rubber are widely used for fixing device rollers because of their high physical properties.

  The thermosetting silicone rubber composition used in these is generally referred to as a millable silicone rubber. It is a diorganopolysiloxane, a vulcanizing agent, a reinforcing filler, an expanding filler, a heat-resistant additive, a colorant, and a dispersion accelerator. Etc. are blended.

  As diorganopolysiloxane, those using methyl, phenyl, and vinyl groups are common, but heat based on methylphenylvinylsilxane using 5-30 wt% of the phenyl groups in the base polymer is used. The curable silicone rubber composition has a low swellability with respect to dimethyl silicone oil as a release agent used for a fixing device roller, and is used for a fixing device such as a fixing roller, a silicone oil application roller, and a fixing belt driving roller. Used as a roller.

  However, in a roller for a fixing device using a silicone sponge rubber manufactured from such a normal thermosetting silicone rubber composition, benzene is generated from the silicone rubber, which has been a problem in the past. In particular, when the use temperature of the fixing device roller is 140 ° C. or higher, there is a problem in that the generation of benzene increases.

  Recently, environmental issues have been affecting OA equipment such as copiers, printers, and facsimile machines, and regulations on volatile organic compounds (VOCs) have become stricter. It has become to. Therefore, in order to solve such problems, an attempt has been made to remove benzene and suppress the amount of benzene generated thereafter by performing post-heating treatment called post-cure for a long time.

  However, in this method, the amount of benzene generated cannot be measured until it is virtually eliminated, and even if it is possible to suppress the generation of benzene at the beginning of use, it is compared afterwards. In a short period of time, the amount of benzene generated again increased, and there was no significant difference between the amount of benzene generated and a roller that was not heated afterwards, which was not an effective means.

  This invention uses a silicone sponge rubber that generates volatile organic compound benzene so as not to deteriorate the environment, and prevents the generation of benzene from fixing devices such as copying machines, printers, facsimiles, etc. It is an object to obtain a fixing device roller having a body.

  The present invention provides a roller for a fixing device in which at least one silicone sponge elastic body layer is provided around a core metal, wherein the silicone sponge elastic body layer uses a dispersion accelerator containing no phenyl group as a dispersion accelerator for the filler, and A roller for a fixing device comprising a silicone sponge obtained by vulcanizing and foaming a thermosetting silicone rubber composition containing a diorganopolysiloxane containing no phenyl group as a base polymer, and the silicone sponge 2. The fixing device roller according to claim 1, wherein a fluororesin layer having a thickness of 20 to 70 [mu] m is provided as a release layer on the outermost layer of the elastic layer.

  According to the present invention, since the silicone sponge elastic material provided on the core metal peripheral surface of the roller for the fixing device of the heat fixing device used in a copying machine, a printer, a facsimile machine or the like is used, a silicone sponge that does not generate benzene is used. By using the device, it is possible to suppress the generation of benzene from the fixing device roller of the device, and it is possible to suppress the deterioration of the environment.

  FIG. 1 schematically shows the configuration of a fixing device 1 such as a copying machine. The fixing device 1 is composed of a fixing device roller 2 and a pressure roller 3 slidably contacting the fixing device roller 2 on its peripheral surface, and the toner 4 adheres between the fixing device roller 2 and the pressure roller 3 by drawing characters, figures and the like. The paper 5 thus moved moves in the direction of the arrow, and during this time, the heater 11 of the fixing device roller 2 heats it, and the toner 4 is welded onto the paper 5.

  The fixing device roller 2 is a belt hollow roller 10 in which a heater 11 is incorporated. The pressure roller 3 is formed by forming one or more silicone sponge elastic layers 16 around the metal core 15. In the present invention, a fixing roller including a fixing roller for performing heat fixing and a pressure roller is used.

  In the present invention, as the silicone sponge elastic layer 16 of the fixing device roller, a thermosetting silicone rubber composition containing diorganopolysiloxane containing no phenyl group as a base polymer is vulcanized and foamed to form a silicone sponge. As the dispersion accelerator, a dispersion accelerator containing no phenyl group is used.

  Silicone sponges using methylphenylvinylsilxan as the base polymer in thermosetting silicone rubber compositions have been found to gradually generate benzene from phenyl groups due to degradation and decomposition at high temperatures, and polyphenyls that do not use phenyl groups. By using siloxane, generation of benzene can be suppressed.

  However, as a result of further experiments, even when a silicone rubber composition that does not use methylphenylvinylsiloxane is used, it is still necessary to further suppress the generation of benzene because a slight amount of benzene is observed. Admitted. Therefore, the inventors investigated vulcanizing agents, reinforcing fillers, bulking fillers, heat-resistant additives, colorants, dispersion accelerators and the like used in silicone sponge compositions. It has been found that a roller for a fixing device using a silicone sponge in which the generation of benzene is reduced to a value that cannot be measured can be obtained by using a toner that does not use.

  The filler dispersion accelerator is generally called “wetter” and is added during the production of the silicone rubber composition in order to improve the dispersibility of the reinforcing filler and enhance physical properties and processability. Is. Silicone resins, alkoxysilanes and siloxanes, hydroxysilanes, silazanes, polyhydric alcohols, and the like are used, and representative examples include silanes containing a phenyl group such as diphenylsilanediol. In particular, thermosetting silicone rubber that requires high strength is widely used for maintaining high strength and improving workability by promoting dispersion of the reinforcing filler.

  As a method of using the dispersion promoter, a method of preparing a composition by adding a reinforcing filler and heating the composition after being added to the silicone rubber base polymer, and mixing with a reinforcing filler in advance to reinforce by heating. There is a method of reacting with the surface of the conductive filler and then adding it to the silicone rubber base polymer to form a composition.

  The vulcanizing agent, reinforcing filler, extending filler, heat-resistant additive, colorant and the like compounded in the thermosetting silicone rubber used in the present invention are not particularly limited, and ordinary thermosetting silicone rubber Although there is no problem in use of what is blended in the composition, it is necessary to use it after sufficiently confirming that there is no possibility of decomposition and generation of benzene during use at a high temperature.

  In the fixing device roller of the present invention, it is preferable to provide a fluororesin layer as a release layer on the outer periphery of the silicone sponge elastic layer. In particular, it is preferable to use PFA resin (perfluoro-alkoxyfluoro plastics) that is easy to manufacture into a thin-walled tube, and the thickness of the PFA resin is preferably 20 to 70 μm. If the thickness of the PFA is less than 20 μm, the tube may have a hole due to wear during use, and if it exceeds 70 μm, the softness of the inner silicone sponge layer may be hindered.

  FIG. 2 shows a roll obtained by using a thin fixing belt made of a polyimide resin and forming the roll into a roll and providing a release layer such as a fluororesin on the surface. A fixing device roller 21 heated from the inside by a heater 22 is used, and a pressure roll similar to that shown in FIG. 1 is used.

Further, FIG. 3 shows that a fixing belt 31 similar to the polyimide resin thin fixing belt used in FIG. 2 is run using drive rollers 32, 33, and 34 arranged in a substantially inverted triangle as shown in FIG. This is a substitute for the fixing roller shown in FIG. 1 or FIG. At this time, the pressure roll 3 is also the same as that shown in FIG. 1. In this case, the drive rollers 32, 33, and 34 are provided with a silicone sponge elastic layer around the core metal, like the pressure roller 3. One layer or a plurality of layers may be formed. The sponge elastic layer is a silicone sponge elastic layer using a dispersion accelerator containing no phenyl group as a filler dispersion accelerator, and a diorganopolysiloxane containing no phenyl group. A silicone sponge obtained by vulcanizing and foaming a thermosetting silicone rubber composition as a base polymer is used.

Example 1
Thermosetting silicone with methyl vinyl polysiloxane as a base polymer, a reinforcing filler added thereto, and a dispersion accelerator not containing a phenyl group as a dispersion accelerator (trade name KE651U, Shin-Etsu Chemical Co., Ltd.) 100 parts by weight were prepared. This was mixed with 0.5 parts by weight of paramethylbenzoyl peroxide, 1.0 part by weight of dicumyl peroxide, 1.5 parts by weight of the foaming agent azobisisobutyronitrile, and 0.5 parts by weight of the colorant Bengala. The raw material composition of thermosetting silicone rubber sponge was processed. Immediately after the composition was continuously extruded by an extruder, the composition was vulcanized and foamed through a hot air vulcanizer at 280 ° C. for 20 minutes. Thereafter, this was cut into a length of 300 mm to prepare a silicone sponge tube having an inner diameter of 15 mm and an outer diameter of 30 mm.

  The sponge was heated in an oven at 200 ° C. for 10 hours to remove low molecular weight substances and decomposition products. Separately, a self-adhesive liquid silicone rubber (trade name: TSE322, GE Toshiba Silicone Co., Ltd.) is thinly applied as an adhesive on the peripheral surface of a 16 mm diameter iron cored bar 41 (FIG. 4) whose surface has been degreased. 4 was inserted into the silicone sponge tube.

  Thereafter, this was heated at 1300 ° C. for 2 hours to be cured and bonded to bond the silicone sponge to the cored bar 41. Thereafter, it was cooled and polished to have an outer diameter of 28 mm, and finally a silicone sponge layer 42 was obtained. A self-adhesive type liquid silicone rubber (trade name x-32-1934, Shin-Etsu Chemical Co., Ltd.) is thinly applied to the sponge layer surface as an adhesive, and the inner surface is chemically treated with an inner diameter of 27.0 mm and a thickness of 50 μm. Inserted into the treated PFA tube 43. Next, this was heated at 150 ° C. for 2 hours to adhere the PFA tube, and the fixing device roller 45 of the present invention was obtained.

  A 2 g sample was taken out from the silicone sponge layer 42 of this fixing device roller, collected in a 20 ml vial, heated at 190 ° C. for 1 hour, and 1 ml of the generated gas was measured by the headspace GC / MS method to measure the amount of benzene generated. However, it could not be detected at 0.1 μg / g or less.

(Comparative Example 1)
A thermosetting silicone rubber produced by using a phenyl group-containing dispersion accelerator using methylphenylvinylpolysiloxane in which about 15% of the amount of the organo group of the base polymer of Example 1 is phenyl was carried out. A silicone sponge tube was prepared by the same composition and production method as in Example 1, and a fixing roller was obtained in the same manner. With respect to the silicone sponge layer of this fixing roller, the amount of benzene measured by the method of Example 1 was a benzene generation amount of 5.3 μg / g.

(Comparative Examples 2 and 3)
A thermosetting silicone rubber (trade name KE904FU, Shin-Etsu Chemical Co., Ltd.) using methyl vinyl polysiloxane as a base polymer and a dispersion accelerator containing a phenyl group as a dispersion accelerator. A silicone sponge tube was manufactured by the method, and the same post-heating treatment as in Example 1 was performed at 200 ° C. for 10 hours to obtain a fixing device roller of Comparative Example 2.

  The post-heating treatment of the silicone sponge of Comparative Example 2 was performed at 220 ° C. for 100 hours for a long time to obtain a fixing device roller of Comparative Example 3. For this fixing device roller, the same amount of benzene as in Example 1 was measured. The amount of benzene generated was 1.7 μg / g for the fixing device roller of Comparative Example 2 and 0.4 μg / g for the fixing device roller of Comparative Example 3. Met. Example 1 and Comparative Examples 1 to 3 are collectively shown in Table 1.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view of a fixing device using a fixing device roller according to an embodiment of the present invention. FIG. 5 is a schematic explanatory view of a fixing device using a fixing device roller according to another embodiment of the present invention. FIG. 5 is a schematic explanatory view of a fixing device using a fixing device roller according to another embodiment of the present invention. Explanatory drawing which shows the side surface of the roller for fixing devices used for implementation of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fixing device, 2, 22 ... Roller for fixing device, 3 ... Pressure roller, 4 ... Toner, 5 ... Paper, 11, 22 ... Heater, 10, 15 ... Core metal, 16 ... Silicone sponge elastic layer, 31... Fixing belt, 32, 33, 34... Driving roller, 41.

Claims (2)

  In a roller for a fixing device in which at least one silicone sponge elastic layer is provided around the core metal, the silicone sponge elastic layer uses a dispersion accelerator that does not contain a phenyl group as a filler dispersion accelerator and contains a phenyl group. A fuser roller comprising a silicone sponge obtained by vulcanizing and foaming a thermosetting silicone rubber composition containing no diorganopolysiloxane as a base polymer.   2. The roller for a fixing device according to claim 1, wherein a fluororesin layer having a thickness of 20 to 70 [mu] m is provided as a release layer on the outermost layer of the silicone sponge elastic layer.

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