JP2009297911A - Method of manufacturing ceramics roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a ceramics roller having a low heat conductivity, with high productivity and without locally causing variance of density in a cylindrical layer. <P>SOLUTION: The method includes: a slurry preparing process in which a raw material containing heat resistant fiber is mixed with water to prepare slurry; a forming process in which a sheet with a thickness of 0.6-6.0 mm is obtained from the slurry; a blanking process in which the sheet is blanked in the thickness direction to obtain a number of ring shaped sheets; and an assembling process in which a required number of ring shaped sheets 2 are inserted into an axial center 5, and forming pieces are compressed and fixed in the longitudinal direction of the axial center. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a ceramic roller including a metal shaft core and a cylindrical body layer formed on the outer peripheral side of the shaft core, and particularly to an electrophotographic apparatus such as an electrophotographic copying machine or a printer using a charged image. The present invention relates to a method for manufacturing a ceramic roller used in a heat fixing apparatus.

  An electrophotographic apparatus such as an electrostatic copying machine or a laser printer projects an optical image onto a uniformly charged photoreceptor surface in the dark, and an electrostatic latent image corresponding to the optical image is formed on the photoreceptor surface. The image is developed by spraying charged toner, which is a developer, on the surface of the photoconductor and electrostatically adhering it, and the surface of the printing paper charged to the opposite polarity to the charge of the toner is superimposed on the surface of the photoreceptor. The image is copied by transferring it onto a paper surface and heating and melting the toner on the paper surface under pressure by a heat fixing roller and then heat-fixing the toner on the paper surface.

  As the heat fixing device portion for fixing the toner on the paper surface with the heat fixing roller, the heat fixing roller is usually composed of two rollers, a heat fixing roller and a pressure roller, or a heat fixing roller, a pressure roller and a conveying roller. And a roller having an endless belt wound between one of a heat fixing roller or a pressure roller and a conveying roller. That is, the printing paper is supported from the back side by a pressure roller or a pressure roller via an endless belt, and is pressed and heated by a heat fixing roller heated from the front side, so that the toner on the paper surface is fused. Heat fixing. The temperature of the heat fixing roller is generally about 150 to 200 ° C. However, when the temperature of the roller is increased, it may temporarily reach a higher temperature due to overshoot.

  In order to fuse the toner on the paper surface by the heat fixing roller, it is heated to a high temperature capable of fusing, but when the heat fixing operation is performed, the printing paper or pressure roller, which is always much lower than the heat fixing temperature, Or since it contacts and rotates with the endless belt, a large amount of heat energy is taken away and cooled at that moment. For this reason, the heat fixing roller needs to be heated to a higher temperature in anticipation of cooling due to such contact, and power consumption increases. Therefore, the pressure roller is required to have a low thermal conductivity, that is, heat insulation. Further, since the pressure roller is in contact with the high-temperature heat fixing roller, heat resistance is also required.

  As such a pressure roller, a ceramic roller comprising a shaft core and a porous ceramic cylindrical layer formed on the outer periphery of the shaft core has been proposed (Japanese Patent Laid-Open No. 2007-272051).

  A ceramic roller disclosed in Japanese Patent Application Laid-Open No. 2007-272051 is a slurry preparation step in which a raw material containing inorganic fibers and water are mixed to prepare a slurry, and molding in which a plate-like or columnar shaped body is obtained from the slurry by wet press molding or papermaking A step of obtaining a molded piece having a hollow portion by making a hole perpendicular to the orientation direction of the inorganic fiber in the molded body, passing the shaft core through the hollow portion of the molded piece, and passing the molded piece in the longitudinal direction of the shaft core And compressing and fixing to a manufacturing method.

However, the ceramic roller manufacturing method disclosed in Japanese Patent Application Laid-Open No. 2007-272051 is due to the press-fitting of the shaft core and the columnar material constituting the cylindrical body layer. (1) Insertion friction generated during assembly to the shaft core As a result, there is a problem that a density variation occurs locally and a portion where heat is easily escaped (high density) is generated, and (2) productivity is lowered due to frictional resistance generated when assembled to the shaft core.
JP 2007-272051 A

  Accordingly, an object of the present invention is to provide a ceramic roller having a shaft core and a ceramic cylindrical layer formed on the outer periphery of the shaft core without causing local density variations in the cylindrical layer. Another object of the present invention is to provide a ceramic roller manufacturing method for manufacturing a ceramic roller having a low thermal conductivity with high production efficiency.

  In such a situation, the present inventors have intensively studied, and as a result, an assembly process for inserting a required number of ring-shaped sheet pieces into the shaft core and compressing and fixing the laminate of the sheet pieces in the longitudinal direction of the shaft core. More preferably, in this assembly process, if the inner diameter of the hollow portion of the ring-shaped sheet piece is larger than the outer diameter of the shaft core, it is localized in the compressed cylindrical body layer. It has been found that a ceramic roller having low thermal conductivity without causing density variation can be produced with high production efficiency, and the present invention has been completed.

  That is, the present invention includes a raw material containing calcium silicate and heat-resistant fibers or a raw material containing inorganic binder and heat-resistant fibers, a slurry preparation step for preparing a slurry by mixing water, and a thickness of 0.6 to 6 from the slurry. A molding process for obtaining a 0.0 mm sheet by suction dehydration molding or papermaking, a punching process for punching the sheet in the thickness direction to obtain a large number of ring-shaped sheet pieces, and a required number of ring-shaped sheet pieces And an assembly step of compressing and fixing the laminated body of the ring-shaped sheet pieces in the longitudinal direction of the axial core, and providing a method for producing a ceramic roller.

  According to the method for producing a ceramic roller of the present invention, a required number of ring-shaped sheet pieces having a thickness of 0.6 to 6 mm are inserted into the shaft core, and then the laminate of the sheet pieces is compressed in the longitudinal direction of the shaft core. Since the fixing step is employed, a ceramic roller having a low thermal conductivity can be manufactured with high production efficiency without causing local density variation in the compressed cylindrical body layer. This effect is particularly remarkable when the inner diameter of the hollow portion of the ring-shaped sheet piece is larger than the outer diameter of the shaft core in this assembling step.

(Slurry preparation process)
The slurry preparation step is a step of preparing a slurry by mixing water with a raw material containing calcium silicate and heat resistant fibers or a raw material containing an inorganic binder and heat resistant fibers. A raw material containing calcium silicate and heat-resistant fibers is preferable in that a material having a lower thermal conductivity can be obtained.

  As calcium silicate, a compound produced by hydrothermal reaction of a siliceous raw material and a calcium raw material in the presence of water is suitable. Examples of calcium silicate crystals include, for example, zonotlite crystals, tobermorite crystals, amorphous C—S—H crystals, etc. In particular, compacts made of zonotolite crystals are lightweight and have a very high specific strength, heat resistance and heat insulation. It is preferable because of its superiority. The zonotlite crystals are the same as those described in Japanese Patent Application Laid-Open No. 2007-272051, and are aggregated and bonded to form secondary particles.

  The heat resistant fiber used in combination with calcium silicate is used as a reinforcing fiber. Heat resistant fibers include heat resistant inorganic fibers and heat resistant organic fibers. Examples of the heat-resistant inorganic fiber include alumina silica fiber, alumina fiber, Christo tile, carbon fiber, glass fiber, slag wool, silica fiber, zirconia fiber, gypsum whisker, silicon carbide fiber, potassium titanate whisker, and aluminum borate whisker. , High silicate fiber, fused silica fiber, rock wool, wollastonite, and the like. Examples of the heat-resistant organic fiber include aramid fiber. In addition, these heat resistant fibers can be used individually by 1 type or in combination of 2 or more types.

  In the slurry preparation step, the slurry may further contain a reinforcing material, a filler, or a lightweight aggregate as an optional component in addition to the heat-resistant fiber and the calcium silicate crystal. By adding such an optional component, a calcium silicate crystal-containing molded body having higher strength can be obtained. Examples of the reinforcing material include cement and gypsum, examples of the filler include talc, diatomaceous earth, and fly ash. Examples of the lightweight aggregate include microsilica, pearlite, shirasu balloon, and glass balloon.

  In the slurry, the amount of each raw material is, for example, 5 to 95 parts by mass, preferably 20 to 60 parts by mass, and 0 to 36 parts by mass of the reinforcing material with respect to 100 parts by mass of the secondary particles of the zonotlite crystals. Preferably, they are 7-15 mass parts, 0-30 mass parts of fillers, and 0-30 mass parts of lightweight aggregate.

  Examples of the raw material mainly composed of the inorganic binder and the heat resistant fiber include the same materials as those disclosed in JP-A No. 2004-301293.

  The inorganic binder is a material that becomes a ceramic component by itself in the drying and firing processes and consolidates the heat-resistant fibers. The inorganic binder is not particularly limited, and examples thereof include glass frit, colloidal silica, alumina sol, silica sol, sodium silicate, titania sol, lithium silicate, and water glass. These inorganic binders can be used alone or in combination of two or more.

  The heat resistant fiber includes a heat resistant inorganic fiber and a heat resistant organic fiber. Examples of the heat-resistant inorganic fiber include alumina silica fiber, alumina fiber, Christo tile, carbon fiber, glass fiber, slag wool, silica fiber, zirconia fiber, gypsum whisker, silicon carbide fiber, potassium titanate whisker, and aluminum borate whisker. , High silicate fiber, fused silica fiber, rock wool, wollastonite, and the like. Examples of the heat-resistant organic fiber include aramid fiber. These heat resistant fibers can be used singly or in combination of two or more.

  In the raw material mainly composed of the inorganic binder and the heat resistant fiber, a particulate heat resistant inorganic material can be blended in addition to the heat resistant fiber. Particulate heat-resistant inorganic materials include clay, calcium carbonate, talc, silica, aluminum, magnesium oxide, calcium oxide, zirconia, titania, sepiolite, kaolin, zeolite, silicon nitride, aluminum nitride, aluminoborosilicate, aluminosilicate, and porous Examples include carbonaceous materials. Moreover, hollow materials, such as hollow ceramics and a glass balloon, can also be used as a particulate heat-resistant inorganic material. In addition, these particulate heat-resistant inorganic materials can be used individually by 1 type or in combination of 2 or more types.

  In the raw material which has an inorganic binder and a heat resistant fiber as a main component, the usage-amount of a heat resistant fiber in a slurry is 50-500 mass parts with respect to 100 mass parts of inorganic binders, Preferably it is 100-300 mass parts. When the amount used is less than 50 parts by mass, the cylindrical body layer is hardly elastically deformed even if the roller is heated and the metal shaft core is thermally expanded in the longitudinal direction of the shaft core, and the cylindrical body layer is cracked. It becomes easy. Moreover, when the usage-amount exceeds 500 mass parts, the intensity | strength of the cylindrical body layer obtained will become inadequate.

(Molding process)
The forming step is a step of obtaining a sheet having a thickness of 0.6 to 6.0 mm from the slurry by a suction dehydration forming method or a paper making method, preferably a paper making method. Further, in the slurry preparation step, when secondary particles of zonotlite crystals are used as a raw material, the forming step is a step of flattening the secondary particles of the zonotlite crystals and making the orientation of the flat zonotolite secondary particles in a certain direction. It may also serve as.

A known method can be applied to the suction dehydration molding method or the papermaking method. In the paper making method, the sheet is formed into a sheet of 0.6 to 6.0 mm by a paper machine that scrapes raw materials such as zonotlite from the slurry. The paper machine is composed of a net for scoring the raw material, a press machine for compressing it, a dryer, and the like, and a long paper machine, a round paper machine, or the like may be used. The density of the sheet is appropriately determined in the range of, for example, 0.2 to 0.5 g / cm ³ according to the bulk density of the cylindrical body layer to be produced. Incidentally, the flattening of the secondary particles of the zonotlite crystal may be performed during the assembly compression process to the shaft core. In this case, the bulk density of the sheet is 0.02 g / cm from the final cylindrical bulk density. Lighten ³ or more. The density of the sheet may be adjusted by changing the bulk of the zonotolite crystal secondary particles in the slurry or the pressure of a press or the like performed after dehydration molding. For example, when the zonotolite crystal secondary particles are made bulky, a sheet having a relatively low bulk density can be obtained. The bulk density of the zonotlite crystal secondary particles is adjusted by appropriately changing the starting material, the concentration of the slurry, the stirring conditions, and the like. The thickness of the sheet (symbol t in FIG. 2) can be adjusted from 0.6 to 6 mm. However, when the thickness is adjusted to 1.2 to 3.4 mm, the influence of density variation generated in the sheet thickness direction is further reduced. This is preferable. The molding pressure is usually 1-100 kgf / cm ² , preferably 1-10 kgf / cm ² . In the case of the papermaking method, the orientation direction of the flat zonotlite secondary particles and the heat-resistant fiber is perpendicular to the direction in which water drops by gravity from the papermaking machine. The sheet obtained by the above method can be dried by a known technique. The drying conditions are usually 50 to 300 ° C for 0.1 to 24 hours, preferably 150 to 250 ° C for 0.1 to 10 hours.

(Punching process)
The punching process is a process of punching a sheet in the thickness direction to obtain a large number of ring-shaped sheet pieces. This punching process will be described with reference to FIG. FIG. 1 is a diagram for explaining an example of a process for obtaining a ring-shaped molded body from a sheet obtained by a suction dehydration method or a papermaking method. In FIG. 1, a sheet molded body 1 having a thickness t is punched out using, for example, a double cylindrical blade (not shown) to obtain a ring-shaped molded piece 2 having an outer diameter d ₂ and an inner diameter d ₁ . A punching machine using a plurality of double cylindrical blades having the same shape is preferably used to obtain a large number of ring-shaped objects by a single punching because the productivity can be improved.

  In addition, what is obtained from the sheet | seat obtained by the suction dehydration molding method or the papermaking method is not limited to said ring-shaped thing, The square-shaped thing which has a round hole may be sufficient. In this case, after assembling to the shaft core, the rectangular columnar object is processed into a cylindrical object.

(Assembly process)
The assembling step is a step of inserting a required number of ring-shaped sheet pieces into the shaft core and compressing and fixing the molded pieces in the longitudinal direction of the shaft core. The assembly process will be described with reference to FIGS. FIG. 2 is a diagram illustrating a process of inserting a large number of ring-shaped sheet pieces into the shaft core, FIG. 3A is a cross-sectional view of a ceramic roller obtained by the manufacturing method of this example, and FIG. It is sectional drawing of the cylindrical body layer before compression used with the ceramic roller of this.

  The shaft core is not particularly limited as long as it is a metal or a hard resin having rigidity to withstand use, and examples thereof include iron, stainless steel, aluminum, copper, brass, carbon steel, polycarbonate, and hard nylon.

As a method of incorporating the ring-shaped sheet pieces 2 into the shaft core 5 having the shaft diameter d _3, a method of inserting the ring-shaped sheet pieces 2 into the shaft core 5 one by one and incorporating them one after another, or stacking several sheets on the shaft core 5 For example, a method of inserting and incorporating a ring-shaped sheet piece 2 and a method of inserting the shaft core 5 into the stacked ring-shaped sheet pieces 2 are exemplified. In the conventional method of press-fitting a column-shaped molded piece into the shaft core, press-fitting resistance occurs, density unevenness occurs in the molded piece, and a portion where heat easily escapes occurs.

When installing the sheet piece second ring-shaped in the axial 5, that the inner diameter _{d 1} of the annular sheet piece 2 is larger than the shaft diameter _{d 3} of the shaft 5, in particular 0.05mm~6mm large, more particularly The size is preferably 0.05 to 2 mm. If there is a difference of at least 0.05 mm between d ₁ and d ₃ , little or no insertion friction will occur, or even if it occurs, the insertion operation will not be affected. How much the difference between the inner diameter d _{1 of the} ring-shaped sheet piece 2 and the shaft diameter d ₃ of the shaft core 5 depends on the material, thickness, number of sheets used, and the gap (X) after compression. The target value may be determined as appropriate in consideration of the target value.

  When the ring-shaped sheet piece 2 is inserted into the shaft core 5, the insertion load per circumferential length of the inner diameter of the cylindrical body layer constituted by the ring-shaped sheet piece 2 is 0 to 80 N / cm, Preferably it is the range of 0-58 N / cm. Strictly speaking, the gap obtained with a load in the vicinity of an insertion load of 80 N / cm can be substantially defined as a gap, although there are a few places where partial contact is made. Even in such a partially contacting gap, density unevenness does not occur in the cylindrical body layer, and when inserting the cylindrical body layer into the shaft core, the insertion resistance is reduced and productivity is improved. The object of the present invention can be achieved. In the case of the conventional press-fitting method, the insertion load may be 580 N / cm, and the insertion load 80 N / cm is a very small load compared to this. When the inner diameter of the cylindrical layer is 22 mm, the insertion load is 0 to 550 N, preferably 0 to 400 N.

  The number of ring-shaped sheet pieces 2 used is 2 to 17, preferably 3.5 to 10, per 10 mm unit length after compression. If the number of sheets used is too small, the thickness of the sheet obtained by the papermaking method or the like becomes too thick, resulting in density unevenness in the papermaking process and density unevenness due to an increased insertion load on the shaft core. On the other hand, if the number of sheets used is too large, the thickness of the sheet obtained by the papermaking method becomes too thin and the strength cannot be obtained. When the length of the cylindrical body layer 1 is 300 mm, 60 to 510, preferably 105 to 300 are used.

  As a method of compressing and fixing the ring-shaped sheet piece 2 so as to have a predetermined compression length Δl in the longitudinal direction of the axis (see FIG. 2), for example, a method of screwing a flange with a female screw or press-fitting And a method of fixing the formed piece and the unevenness formed on the shaft core by knurling. Thereby, the ceramic roller 10 can generate rotational torque by the compressive force between the flanges 4. Therefore, the adhesive between the shaft core 5 and the cylindrical body layer 7 may not be used. Moreover, since the flexible paper is compressed in the longitudinal direction of the cylindrical body layer 7, no gap is generated between the papers, and no gap is generated on the surface of the cylindrical body layer. In this compression and fixing step, the thickness of the ring-shaped sheet piece 2 constituting the cylindrical body layer is approximately 0.5 to 5 mm before compression, and is approximately 0.5 to 5 mm before compression, and 1.2 to 3.4 mm before compression. Is approximately 1 to 3 mm.

In ceramic roller 10, the axis longitudinal length l ₁ after being mounted in the axial 5 is smaller than axial longitudinal length l ₀ before being mounted in the axial 5. That is, l ₁ <l ₀ and l ₀ −l ₁ = Δl is the compression length. The compression length Δl is a reduction obtained by applying pressure accompanied by a density increase of 0.02 g / cm ³ or more when the density in the axial direction of the cylindrical body layer 7 is compressed and fixed. With this compression length, the frictional resistance between the flange and the end face of the cylindrical body layer is sufficient, and a desired rotational torque can be obtained. The desired rotational torque varies depending on the specifications of the heat fixing device of the electrophotographic apparatus to be used, and may be determined as appropriate within a range where the compression pressure increases in density by 0.02 g / cm ³ or more.

  In the production method described above, the firing step (autoclave) is an optional step. However, when performing the firing step, it is preferable to obtain the sheet-like sheet piece 2 after firing in that no dimensional change occurs. After mounting the sheet piece on the shaft core, a surface layer such as a fluorine resin layer such as a film of PFA resin, a silicone rubber layer, or a glass layer can be further coated on the outer periphery of the cylindrical body layer by a known method. Thereby, the surface can be smoothed, the slidability can be improved, and the releasability can be imparted.

  The ceramic roller 10 obtained by the manufacturing method of the present invention includes a metal shaft core 5, a gap (air layer) 9, and a ceramic cylindrical body layer 7 in order from the center toward the outside (see FIG. 3). Ceramics refers to a material mainly composed of a nonmetallic inorganic material. The shaft core 5 includes a flange 4 that can hold the cylindrical body layer 7 attached to the shaft core 5 from both sides with a predetermined pressing force, and a journal portion 3. That is, the shaft core 5 and the cylindrical body layer 7 are fixed by frictional resistance between the flanges 4 located on both sides of the shaft core 5 and the end face of the cylindrical body layer 7. The cylindrical body layer 7 is formed by laminating approximately several hundred ring-shaped sheet pieces having the same physical properties and the same size, and is compressed in the longitudinal direction of the shaft core 5 and fixed to the shaft core 5. Note that the gap (air layer) 9 is not necessary, but when it is inserted, the insertion friction hardly occurs when the cylindrical body layer is inserted into the shaft core. There is no variation. Moreover, since air exists between the shaft core and the cylindrical body layer, the thermal conductivity can be lowered.

  In the ceramic roller of the present invention, the gap (X) between the shaft core and the cylindrical body layer is 0 <X ≦ 3 mm, preferably 0.05 ≦ X ≦ 2 mm, more preferably 0.05 ≦ X. ≦ 1 mm, more preferably 0.05 ≦ X ≦ 0.1 mm. In the method in which the cylindrical body layer is pressed into the shaft core and the cylindrical body layer is fixed to the shaft core, the cylindrical body layer is damaged at the time of press-fitting, or friction powder is filled in the gap to cause insertion friction, resulting in density variation (heat Unevenness) occurs. Further, if the gap exceeds 3 mm, the frictional force between the contact surfaces of the cylindrical bodies is reduced, and there is a concern about the rotational displacement between the cylindrical bodies. Although the cylindrical body layer (heat insulating layer) can be thickened by increasing the outer diameter of the cylindrical body layer, it is not preferable because it becomes an obstacle to downsizing of the entire apparatus.

  The gap (X) is preferably completely non-contact, but is not limited thereto, and there may be a slight contact portion. The gap (X) can be determined using, for example, an inner diameter measuring device. Examples of the inner diameter measuring device include a three-point inner micrometer having a minimum display amount of 0.001 mm. That is, the gap (X) disassembles the ceramic roller, takes out the cylindrical body layer, disassembles it into unit lengths (block bodies) as necessary, compresses the block bodies again to the original length, and then The inner diameter may be measured with an inner diameter measuring instrument and obtained from the difference from the outer diameter of the shaft core.

In the ceramic roller of the present invention, the bulk density of the ceramic of the cylindrical body layer is usually 0.05 to 0.7 g / cm ³ , preferably 0.25 to 0.5 g / cm ³ . Further, the heat capacity of the ceramic of the cylindrical body layer is 0.04 to 0.65 J / K · cm ³ , preferably 0.04 to 0.4 J / K · cm ³ . Moreover, the thermal conductivity of the ceramics only of the compressed cylindrical body layer is 0.01 to 0.15 W / m · K, preferably 0.04 to 0.15 W / m · K, more preferably. 0.06 to 0.12 W / m · K. Further, the thermal conductivity of the ceramic roller comprising the shaft core and the cylindrical body layer of the present invention is 0.04 to 0.15 W / m · K, preferably 0.06 to 0.12 W / m · K. .

The heat capacity (KJ / cm ³ ) can be calculated from the value of bulk density by pulverizing a sample, measuring 50 g of the sample using a high temperature sample dropping type specific heat measuring device, and measuring the specific heat. Moreover, the thermal conductivity (W / m · K) of the ceramic of the compressed cylindrical body layer is a flat plate having a width of 100 mm, a thickness of 20 mm, and a length of 50 mm, which is the same density as that of the ceramic roller. The thermal conductivity (W / m · K) of the ceramic roller composed of the shaft core and the cylindrical body layer is measured on the surface of the cylindrical test body according to JIS R2618 unsteady hot wire method. It is measured at room temperature with a rapid thermal conductivity meter QTM-500 (manufactured by Kyoto Electronics Industry Co., Ltd.). In addition, said cylindrical body layer may be comprised from the ceramic layer of different bulk density and heat capacity. For example, the portion close to the outer peripheral surface may be a ceramic layer having a relatively lower heat capacity than the inside.

  Since the ceramic roller of the present invention has a gap between the shaft core and the cylindrical body layer, there is no density unevenness due to insertion friction, and the thermal conductivity is uniform and small, so that the heat insulation is excellent. For this reason, it can be used for a ceramic roller requiring heat insulation used in a heat fixing device mounted on an electrophotographic apparatus such as an electrophotographic copying machine or a printer. That is, the use of the ceramic roller of the present invention is called by various names, for example, a pressure roller, a conveyance roller, an auxiliary roller, a drive roller, a peeling roller, a tension roller, a drive roller, a guide roller, etc. Is mentioned.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

(Formation of zonotlite crystals)
As a calcareous material, quick lime was poured into 24 times the amount of 90 ° C. hot water and digested for 30 minutes while stirring with a rotating blade rotating at 160 rpm to obtain lime milk. Next, silica powder (Izu silica special powder D) as a siliceous raw material is added to the obtained lime milk so that the CaO / SiO ₂ molar ratio is 1.0, and at the same time, the total of quick lime and silica powder 30 times the amount of water was added to make a uniform slurry, and the mixture was hydrothermally reacted for 4 hours at 16 kg / cm ² in the container while stirring at 120 rpm in an autoclave. Solids in the obtained slurry were substantially composed of zonotolite crystals, and formed spherical secondary particles having a diameter of 30 to 130 μm in which a large number of acicular crystals as primary particles were gathered.

(Slurry preparation process)
5 parts by weight of Portland cement (ordinary Portland cement, manufactured by Ube Mitsubishi Cement Co., Ltd.), 10 parts by weight of glass fibers (CS6J-888S, manufactured by Nittobo Co., Ltd.) 15 parts by weight of small-diameter glass fiber (Q fiber, manufactured by Manville), 0.05 part by weight of a flocculant (Sunfloc N-OP, manufactured by Sanyo Kasei Kogyo Co., Ltd.), and mixed uniformly to make a slurry for papermaking Got.

(Molding process (I))
The slurry obtained in the slurry preparation process is made with a long paper making machine to form paper, then pressed with a pressure of about 4 kgf / cm ² , dried, and a density of 0.35 g / cm ³ , thickness A sheet-like heat insulating paper of 1.0 mm was obtained.

(Punching process)
A ring-shaped sheet piece having an outer diameter of 39.5 mm and an inner diameter (hollow part diameter) of 22.5 mm was conveniently obtained by punching from the obtained sheet-like heat insulating paper. In the punching process, a punching machine having a double cylindrical blade was used and 20 pieces were picked / performed 14 times per time (see FIG. 1).

(Assembly process)
Subsequently, the ring-shaped sheet pieces 2 were successively inserted into the shaft core 5 made of stainless steel having a shaft diameter of 22.0 mm to obtain a laminated body in which 373 pieces of divided molded pieces were connected. The insertion load at this time was zero. This laminated body was compressed in the longitudinal direction of the axial center using a flange to obtain a ceramic roller having a heat insulating layer having a length of 300 mm and a bulk density of 0.45 g / cm ³ . The obtained ceramic roller was measured for the gap (X) between the shaft core and the cylindrical body layer, the thermal conductivity of the cylindrical body layer, and the maximum and minimum values of the density of the cylindrical body layer. The results are shown in Table 1. The gap (X) between the shaft core and the cylindrical body layer was performed by the following method. Further, the thermal conductivity of the cylindrical body layer was measured by separately preparing four samples having the same density. Moreover, the maximum value and the minimum value of the density of the cylindrical body layer were obtained from 30 results measured every 5 mm of the cylindrical body length. Moreover, the average value and thermal conductivity difference of the ceramic roller were calculated | required from the result of having measured the surface of the cylindrical body layer ten places.

(Measurement of gap (X))
Remove the flange of the ceramic roller, take out the block body with a length of 10 mm at an arbitrary part of the cylindrical body layer, compress the block body again to the original length, and then reduce the inner diameter to the minimum display amount. Measurement was performed with a 0.001 mm three-point inner micrometer, and the difference from the outer diameter of the shaft core was halved. The block body was selected from 10 different places in the cylindrical body layer.

  Example, except that a sheet-like heat-insulating paper having a thickness of 1.4 mm was obtained instead of the sheet-like heat-insulating paper having a thickness of 1.0 mm, and the number of ring-shaped sheet pieces 373 was 267. A ceramic roller was prepared in the same manner as in No. 1 and evaluated. The results are shown in Table 1.

  The same as Example 2 except that a ring-shaped sheet piece having an outer diameter of 39.5 mm and an inner diameter of 22.2 mm was punched instead of punching a ring-shaped sheet piece having an outer diameter of 39.5 mm and an inner diameter of 22.5 mm. A ceramic roller was prepared by the method and evaluated. The results are shown in Table 1.

  Instead of punching a ring-shaped sheet piece having an outer diameter of 39.5 mm and an inner diameter of 22.5 mm, a ring-shaped sheet piece having an outer diameter of 39.5 mm and an inner diameter of 22.1 mm was punched, and the number of stacked ring-shaped sheet pieces A ceramic roller was produced and evaluated in the same manner as in Example 2 except that 267 was changed to 268. The results are shown in Table 1.

  Example 1 except that instead of the molding step (I) (paper making method), the following molding step (II) (suction dehydration molding method) was used, and the number of ring-shaped sheet pieces 373 was set to 113. A ceramic roller was produced in the same manner as in Example 1, and evaluated. The results are shown in Table 1.

(Molding process (II))
The slurry obtained in the slurry preparation process in the same manner as the papermaking method is poured into a mold for suction dehydration molding, wet pressed at a pressure of about 40 kgf / cm ² while performing suction dehydration, and then dried at 110 ° C. A sheet-like heat insulating paper having a density of 0.35 g / cm ³ and a thickness of 3.3 mm was obtained.

  Except that the amount of slurry input in the molding step (II) was increased 1.5 times to obtain a sheet-like heat insulating paper having a thickness of 5.0 mm, and the number of ring-shaped sheet pieces 113 was 75. A ceramic roller was produced in the same manner as in Example 5 and evaluated. The results are shown in Table 1.

Comparative Example 1
Attempting to obtain a sheet-like heat-insulating paper with a thickness of 0.4 mm by increasing the paper-making speed in the forming step (I), but cannot be peeled from the paper-making net and cannot be made into paper. It was.

Comparative Example 2
Except that the amount of slurry input in the molding step (II) was increased 2.4 times to obtain a sheet-like heat insulating paper having a thickness of 8.0 mm, and the number of ring-shaped sheet pieces 113 was 47. A ceramic roller was produced in the same manner as in Example 5 and evaluated. The results are shown in Table 1.

  In Examples 1 to 6, the density variation of the cylindrical body layer is smaller than that in Comparative Example 2. Since the paper which comprises a cylindrical body layer is thicker in Comparative Example 2 than Examples 1-6, when a compressive load is applied, pressure propagation is poor in one paper, and density unevenness occurs in the thickness direction. This is because in Examples 1 to 6, the paper was thin, and the paper was uniformly pressed in the thickness direction and local density variations were not caused.

  The ceramic roller obtained in Example 1 was a ceramic roller having an outer diameter of 40 mm and a length of 300 mm, in which a PFA tube having a thickness of 30 μm was further adhered to the peripheral surface of the cylindrical body layer with a silicone rubber adhesive. Then, using a device that presses and heats the ceramic roller for the heating roller with a built-in halogen lamp, the heating roller is operated for 100 hours under the conditions of a heating temperature of 200 ° C., a rotation speed of 100 rpm, and a total load of 30 kgf. When observing the destruction situation, no abnormalities were found.

The figure explaining an example of the process of obtaining a ring-shaped molded piece from a sheet | seat. The figure explaining an example of an assembly | attachment process. (A) is sectional drawing of a ceramic roller, (B) is sectional drawing of the cylindrical body layer (laminate) before compression used with the ceramic roller of (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet-like formation body 2 Ring-shaped sheet piece 3 Journal part 4 Flange 5 Metal shaft core 7 Cylindrical body layer 9 Crevice 10 Ceramics roller

Claims (4)

A raw material containing calcium silicate and heat-resistant fibers or a raw material containing inorganic binder and heat-resistant fibers, and a slurry preparation step of mixing water to prepare a slurry;
A molding step of obtaining a sheet having a thickness of 0.6 to 6.0 mm from the slurry by suction dehydration molding or papermaking;
Punching the sheet in the thickness direction to obtain a large number of ring-shaped sheet pieces; and
A method of manufacturing a ceramic roller comprising: an assembly step of inserting a ring-shaped sheet piece into a required number of cores and compressing and fixing the laminate of the ring-shaped sheet pieces in the longitudinal direction of the axis .   2. The method for manufacturing a ceramic roller according to claim 1, wherein the number of sheets used per 10 mm after compression of the laminate of the ring-shaped sheet pieces is 2 to 17 sheets.   3. The method of manufacturing a ceramic roller according to claim 1, wherein an inner diameter of the hollow portion of the ring-shaped sheet piece is larger than an outer diameter of the shaft core in the assembling step.   The fixation of the laminated body of the shaft core and the ring-shaped sheet piece is based on frictional resistance between flanges located on both sides of the axial core and end faces of the laminated body. 4. A method for producing a ceramic roller according to any one of 3 above.

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