JP4742746B2 - Endless belt manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an endless belt applied to, for example, a photoreceptor, a transfer belt, and a fixing belt in an electrophotographic apparatus.

  In an electrophotographic apparatus, a rotating body made of metal, resin, or rubber is used for a photoreceptor, a transfer body, a fixing body, etc., but the rotating body can be deformed for downsizing or high performance of the apparatus. In some cases, a resin belt having a small thickness is used. The material is preferably a polyimide (hereinafter abbreviated as “PI”) resin or a polyamideimide (hereinafter abbreviated as “PAI”) resin in terms of strength, dimensional stability, heat resistance and the like. . In this case, if there is a seam in the belt, a defect due to the seam occurs in the output image. Therefore, an endless belt without a seam is preferable.

  In order to produce an endless belt, there are a centrifugal molding method in which a film-forming resin solution is applied to the inner surface of a cylindrical body, and the film is formed by drying while rotating, or an inner surface coating method in which the film-forming resin solution is spread on the inner surface of the cylindrical body. However, in these inner surface film-forming methods, when the film-forming resin solution is heated and reacted, it is necessary to remove the film from the cylindrical body and place it on the outer mold.

  As another method for producing an endless belt, for example, a film-forming resin solution is applied to the surface of a cylindrical core body by a dip coating method, dried, heated and reacted as necessary, and then the film is coated with the core body. There is also a method of peeling from (see, for example, Patent Document 1). This method is more advantageous than the inner surface film-forming method because it does not require man-hours for mounting on the outer mold.

  In the outer surface coating method, after the film-forming resin solution is applied to the surface of the core body, the solvent is dried in a drying furnace heated to a temperature of 50 to 200 ° C. After the solvent drying, the temperature is further increased. When the residual solvent is completely removed or the film-forming resin is reactive, the reaction is completed.

  In that case, a high temperature of 250 ° C. or higher is usually required. In order to heat to high temperature, it is possible to carry out from drying to high temperature heating in the same drying furnace. It is also preferable to make it. In this case, after the drying process, the temperature of the core body is once lowered, and then the core body can be put into a heating furnace and heat-treated (see, for example, Patent Document 2).

Here, in general, in a drying furnace, heated air is blown to the core to raise the temperature of the core, but when air is blown, if dust is contained in the air, foreign matter will be mixed into the coating film. As a result, an image quality defect is caused, which is not preferable. For this reason, the dust has been removed by passing through a filter before blowing air. As the filter, a HEPA (High Efficiency Particulate Air) filter or a quasi-HEPA filter capable of collecting 90% or more of particles having an average particle diameter of 0.5 to 1 μm is used.
On the other hand, in the heating furnace, the dried film is not as soft as the coating film before drying, and does not cause image quality defects due to the inclusion of foreign matter. It was enough if the cleanliness was maintained.
JP 2002-91027 A JP 2003-334830 A

  However, in recent years, in electrophotographic apparatuses, quality requirements for endless belts applied to photoreceptors, transfer belts, fixing belts, and the like have increased, and strict quality with fewer surface defects has been demanded. On the other hand, the heating furnace contains the same amount of dust as in the air outside the furnace, so that the dust adheres to the coating and is heated so that the foreign matter is mixed into the coating. Although it is not, the surface foreign material defect is produced. This surface foreign matter defect has not been a problem level at the conventional quality level, but has been recognized as a problem level with the improvement of the required quality level in recent years.

  An object of the present invention is to solve the above problems. That is, an object of the present invention is to provide an endless belt manufacturing method that suppresses the occurrence of surface foreign matter defects resulting from the heat treatment of the film.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1>
A drying step of forming a film by drying a coating film formed on the outer peripheral surface of the cylindrical core body by applying a film-forming resin solution containing a solvent;
In the endless belt manufacturing method for manufacturing an endless belt, at least through a heating step of heating the film by blowing hot air having a temperature of 250 ° C. or more to the film formed on the outer peripheral surface of the cylindrical core body,
The number of particles or particle diameter 0.5μm present per unit volume of the hot air blown to the coating state, and are 35300 pieces / m ³ or less, a gas hot air blown to the film is heated above 250 ° C. an endless belt manufacturing method comprising der Rukoto those obtained by filtration through a heat filter.

< 2 >
The hot air blown to the film is arranged so that the axial direction substantially coincides with the vertical direction, and the film is blown from the upper side to the lower side with respect to the cylindrical core body formed on the outer peripheral surface,
It is an endless belt manufacturing method as described in < 1 > whose maximum wind speed of the hot air sprayed on the said film | membrane is 3 m / sec or less in the exit of the said heat-resistant filter.

< 3 >
The heating step supplies hot air blown to the film in the heating furnace in a state where the cylindrical core body having the film formed on the outer peripheral surface is disposed in a heating furnace, and heats the film. It is performed while exhausting the gas after finishing out of the heating furnace,
The endless belt manufacturing method according to <1> or <2> , wherein at least part of the gas after the heating of the coating is circulated in the heating furnace and reused.

< 4 >
A mixed gas obtained by mixing the gas after the heating of the film and a gas outside the heating furnace is supplied into the heating furnace as hot air blown to the film,
< 3 > The method for producing an endless belt according to < 3 >, wherein the gas concentration of the solvent present in the heating furnace is maintained at 0.5 Vol% or less.

< 5 >
In the heating step, the cylindrical core handling jig is fixed to the cylindrical core body peripheral surface so that the axial direction of the cylindrical core body in which the film is formed on the outer peripheral surface coincides with the vertical direction. After being fixed to the heating table via, the cylindrical core fixed to the heating table is placed in a heating furnace,
When the cylindrical core body handling jig is fixed to the inner peripheral side by contacting the inner peripheral surface of the cylindrical core body, and when the fixed base is fixed to the inner peripheral side, An endless belt manufacturing method according to any one of <1> to < 4 >, comprising: a shaft bar attached to the fixed base so as to substantially coincide with an axial line of a cylindrical core body. ,
An endless belt manufacturing method, wherein the heating table includes a base and a convex portion provided on a surface opposite to the bottom surface of the base and capable of fitting with the shaft rod.

< 6 >
In the heating step, the cylindrical core body fixed to the heating table is fixed to the heating table so that the axial direction of the cylindrical core body with the coating formed on the outer peripheral surface coincides with the vertical direction. Is an endless belt manufacturing method according to any one of <1> to < 4 >, wherein the endless belt is disposed in a heating furnace,
The heating table includes a base and a convex portion that is provided on a surface opposite to the bottom surface of the base and can be fitted to the inner peripheral surface side and / or the outer peripheral surface side of the cylindrical core body. Is an endless belt manufacturing method.

< 7 >
The endless area according to < 5 > or < 6 >, wherein the area of the bottom surface of the heating table is 1.5 to 2.5 times the sum of the area of the end surface of the cylindrical core and the opening. It is a belt manufacturing method.

< 8 >
The hot air is blown from the upper side to the lower side of the cylindrical core,
In the endless belt manufacturing method according to any one of < 5 > to < 7 >, the base includes an opening that penetrates the bottom surface and a surface opposite to the bottom surface. is there.

< 9 >
At least a portion of the heating table that contacts the cylindrical core body side is made of a material having a thermal conductivity of 25 to 250 kcal / mhr ° C., a porous body, a frame-shaped member, and a large number of minute protrusions provided on the surface of the heating table. And / or the endless belt manufacturing method according to any one of < 5 > to < 8 >, comprising a large number of minute recesses provided on the surface of the heating table.

<1 0 >
< 5 > to < 9 >, according to any one of < 5 > to < 9 >, wherein at least a part of at least a part of the heating table that contacts the cylindrical core is a point contact and / or a line contact. It is a belt manufacturing method.

<1 1 >
In the endless belt manufacturing method according to any one of <1 > to <4 > , the cylindrical core body in which the coating is formed on an outer peripheral surface is suspended from an upper portion of the heating furnace. is there.

<1 2 >
In the drying step, after fixing the cylindrical core body, on which the coating film is formed on the outer peripheral surface, to a drying table, the furnace is previously placed in a drying furnace heated to 50 ° C. or more and heated. The endless belt manufacturing method according to any one of <1> to <1 1 > performed by:
Before the cylindrical core body with the coating film formed on the outer peripheral surface is fixed to the drying table, the drying table is pre-heated to a temperature within the range of 50 ° C. to the furnace temperature of the drying furnace. It is an endless belt manufacturing method characterized by the above-mentioned.

<1 3 >
< 2 > The endless belt manufacturing method according to <1>, wherein the pre-heat treatment is performed using the drying furnace.

<1 4 >
After the drying step, the drying table taken out from the drying furnace is cooled to a temperature of less than 50 ° C. while the cylindrical core body with the film formed on the outer peripheral surface is fixed. Removing the cylindrical core body with the coating formed on the outer peripheral surface before fixing, fixing the cylindrical core body with the coating film formed on the outer peripheral surface, and placing it again in the drying furnace. <1 2 > or <1 3 > characterized in that the endless belt manufacturing method is characterized.

<1 5 >
The endless belt manufacturing method according to any one of <1 2 > to <1 4 >, wherein the drying base is provided with a mechanism for rotating the cylindrical core.

<1 6 >
The drying table includes one or more fixing members for fixing the cylindrical core,
<1 2 > to <1 5 >, wherein at least one fixing member can be deformed and / or moved on the drying table in accordance with the axial length of the cylindrical core. It is an endless belt manufacturing method as described in any one of these.

<1 7 >
The solvent includes a water-soluble solvent having a boiling point exceeding 100 ° C .;
The drying step is performed by placing the cylindrical core body having the coating film formed on the outer peripheral surface thereof in a drying furnace in which the furnace temperature is maintained at 50 ° C. or higher,
The heating step is performed by disposing the cylindrical core body having the coating formed on the outer peripheral surface thereof in a heating furnace in which the furnace temperature is maintained at 250 ° C. or higher,
The gas containing the solvent volatilized from the coating film in the drying furnace is discharged outside the drying furnace, and the gas containing the solvent volatilized from the film in the heating furnace is discharged outside the heating furnace. <1> to <1 6 >, the endless belt manufacturing method according to any one of
By passing the gas containing the solvent discharged from the heating furnace and / or the drying furnace through a heat exchanger having a heat transfer wall temperature of 40 ° C. or less, the solvent is liquefied from the gas containing the solvent. And collecting the endless belt.

< 18 >
The gas containing the solvent discharged from the heating furnace and / or the drying furnace is passed through the heat exchanger and then passed through a wet packed tower using water to dissolve the solvent in the water. The endless belt manufacturing method according to <1 7 >, wherein the endless belt is collected.

  As described above, according to the present invention, it is possible to provide an endless belt manufacturing method that suppresses the occurrence of surface foreign matter defects resulting from the heat treatment of the film.

The endless belt manufacturing method of the present invention includes a drying step of forming a film by drying a coating film formed on the outer peripheral surface of the cylindrical core body by applying a film-forming resin solution containing a solvent; In the endless belt manufacturing method for manufacturing an endless belt, at least a heating step of heating the film by blowing hot air having a temperature of 250 ° C. or more to the film formed on the peripheral surface, the hot air blown to the film number of particles above particle diameter 0.5μm present per unit volume of, 35300 pieces / m ³ Ri der below the hot air blown onto the film is heated above 250 ° C. gas by filtration through a heat filter der Rukoto those obtained characterized.
Therefore, according to this invention, generation | occurrence | production of the surface foreign material defect resulting from the heat processing of a membrane | film | coat can be suppressed. In order to more reliably suppress the occurrence of surface foreign matter defects, the number of particles having a particle diameter of 0.5 μm or more present per unit volume of hot air blown to the film is 3530 particles / m ³ or less. More preferably, it is more preferably 353 particles / m ³ or less, and the smaller the number of particles having a particle diameter of 0.5 μm or more per unit volume, the better.

In addition, endless belts are usually manufactured in an environment where a certain level of cleanliness of around class 10000 is ensured, and in a form that uses a higher degree of cleanliness as needed. It is very unlikely that the foreign matter (particles) will cause surface foreign matter defects, and the size of particles that may cause the occurrence of surface foreign matter defects is 5 μm or more in terms of particle diameter.
Accordingly, the number of particles of 5 μm or more is more preferably 20 particles / m ³ or less, and further preferably 2 particles / m ³ or less.

The number of particles having a particle diameter of 0.5 μm or more present per unit volume of hot air blown to the film is equal to that contained in the hot air immediately before being blown to the film formed on the outer peripheral surface of the cylindrical core. It means a value obtained by measuring the number of foreign matters (particles) with a particle counter.
Here, “equivalent to being contained in hot air” means that in reality it is difficult to monitor the number of foreign substances contained in hot air, so the gas (usually air) that is the source of hot air is not heated. Means the measured value.
In addition, “immediately before the film is first sprayed” means, for example, that hot air removed by a filter or the like passes through the duct and is arranged so that the axial direction coincides with the vertical direction. In the case of spraying from the upper side to the lower side of the formed cylindrical core, it means the range from the duct outlet to the upper side of the cylindrical core, and in the duct affected by dust generation from the duct. In addition, the vicinity of the central portion of the cylindrical core body and the lower range that are affected by the dust generation of the cylindrical core body itself are excluded.
In addition, the measurement of the number of foreign substances is performed for 10 minutes at one place using a particle counter model 237A manufactured by Transtec.

  There is no particular limitation on the method for obtaining hot air having a high degree of cleanness in which foreign matters (particles) of a certain size or larger such as dust or dust as described above are removed. For example, normal temperature air is used as a HEPA filter, a quasi-HEPA filter, or the like. This can be heated to 250 ° C. or higher after filtration. However, in this method, once filtered air is heated by a heater or the like and then sprayed onto the film, dust generation due to heating members such as a heater is inevitable at the stage of heating after filtration, so surface foreign object defects In some cases, the high degree of cleanliness necessary for suppressing the occurrence of the occurrence of the occurrence of the occurrence of the occurrence of the occurrence of.

For this reason, it is most preferable to filter with a filter after heating the air, but conventionally used HEPA filters and quasi-HEPA filters cannot withstand high temperatures of 250 ° C. or higher. However, in recent years, heat resistant filters (heat resistant filters) such as HEPA filters and quasi-HEPA filters that can withstand high temperatures of 250 ° C. or higher have begun to be marketed. Therefore, it is preferable to use such heat resistant filters.
When using a heat-resistant filter, it can be filtered with the heat-resistant filter immediately before spraying high-temperature air heated to 250 ° C. or higher in advance on the coating formed on the outer peripheral surface of the cylindrical core. It is easy to obtain hot air with a high degree of cleanness that satisfies the above conditions.
A duct or the like may be provided between the heat-resistant filter and the cylindrical core body on which the film is formed on the outer peripheral surface, in order to blow hot air. Substantially no member is disposed between the outlet side of the heat-resistant filter and the cylindrical core body on which the film is formed on the outer peripheral surface so that hot air that has passed through the heat-resistant filter is directly blown onto the film. It is preferable.

In addition, as the heat-resistant filter, a filter medium and a frame member constituting the filter can be made of a member having heat resistance of hot air temperature, that is, 250 ° C. or more. For example, as a filter medium, glass cotton, as a frame member The thing which consists of stainless steel etc. is mentioned. Moreover, as a preferable dust removal performance of such a heat-resistant filter, the collection efficiency of particles having a particle diameter of 0.5 to 1 μm is 90% or more.
A commercially available filter can be used as the heat resistant filter satisfying such specifications, and examples thereof include an Atmos heat resistant 500 ° C. quasi-HEPA filter GCW manufactured by Nippon Mining Co., Ltd.

  In addition, it can select suitably according to the temperature of a hot air, and the composition of the membrane | film | coat used as the object of heat processing, for example, when producing the endless belt which consists of PI resin, the inside of the range of 300-380 degreeC is preferable, from PAI resin In the case of producing an endless belt, the temperature is preferably in the range of 250 to 280 ° C., and the heat resistant filter to be used is appropriately selected to have heat resistance equal to or higher than the above temperature.

In the heating step, hot air may be blown from any direction on the cylindrical core body with the coating formed on the outer peripheral surface, but from the viewpoint of effectively suppressing dust generation, the coating is applied to the outer peripheral surface. It is preferable to blow hot air from the upper side to the lower side of the cylindrical core body in a state where the formed cylindrical core body is arranged so that the axial direction substantially coincides with the vertical direction.
Furthermore, when using a heat-resistant filter, it is preferable to arrange the heat-resistant filter on the upper side of the vertically disposed cylindrical core body with the outlet side facing downward.
In addition, it is preferable that the maximum wind speed of a hot air is 3 m / sec or less at the exit of a heat-resistant filter, and it is more preferable that it is 1.5 m / sec or less. If the maximum wind speed exceeds 3 m / sec, the dust collection performance of the heat-resistant filter may deteriorate. However, in practice, the wind speed is preferably 0.5 m / sec or more.

In addition, the heating step may be performed in a space open to the outside (open system), but since the thermal efficiency is low and it is difficult to obtain a sufficient cleanliness, the practicality is low, Usually, it is particularly preferable to carry out in a space (closed system) closed to the outside such as in a heating furnace.
When a heating furnace is used in this way, the heating step supplies hot air blown to the coating into the heating furnace in a state where a cylindrical core body with the coating formed on the outer peripheral surface is disposed in the heating furnace. This is done while exhausting the gas after heating to the outside of the heating furnace, but in order to improve the thermal efficiency, at least a part of the gas after finishing the coating is circulated in the heating furnace. It is preferable to reuse. In addition, in such a circulation system, either a partial circulation system that circulates a part of the gas after finishing the heating of the film or a complete circulation system that circulates all of the gas after the heating of the film is finished. The complete circulation method is preferable from the viewpoint of obtaining high thermal efficiency.

However, depending on the type of solvent contained in the film-forming resin solution used to form the coating film and the temperature of the hot air, even in the heating process, the residual solvent in the film that was not volatilized in the drying process volatilizes and the heating furnace In addition to slowing down the evaporation rate of the solvent, it may be unfavorable for safety.
Therefore, in such a case, a mixed gas obtained by mixing the gas after finishing the coating and a gas outside the heating furnace is supplied into the heating furnace as hot air blown to the coating, It is preferable to adjust the gas concentration of the solvent present so that it is preferably maintained at 0.5 Vol% or less, more preferably 0.2 Vol% or less. The gas outside the heating furnace means a gas that does not substantially contain the solvent contained in the film-forming resin solution, and usually air in the external environment is used.

Next, the heating furnace used for the endless belt manufacturing method of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a heating furnace used in the endless belt manufacturing method of the present invention, and shows the configuration in the heating furnace.
In the figure, 100 is a heating furnace, 102 is a housing, 104 is an inner chamber, 106 is a heat source, 108 is a heat-resistant filter, 110 is a cylindrical core body with a coating formed on the outer peripheral surface, and 112 is a heating table. The white arrow in the middle means the flow of airflow.
The heating furnace 100 includes a housing 102, an inner chamber 104 and a heat source 106 provided in the housing 102. A heat resistant filter 108 is disposed on the inner chamber 104, and air heated by a heat source 106 disposed adjacent to the inner chamber 104 is supplied to the space in the inner chamber 104 through the heat resistant filter 108. It is like that. The hot air supplied from the upper part of the inner chamber 104 through the heat-resistant filter 108 moves to the lower part of the inner chamber 104, is exhausted from the lower part of the inner chamber 104 into the housing 102, and is then supplied to the heat source 106 again. Recycled. In order to circulate the air in the heating furnace 100, a fan is provided on the inlet side or the outlet side of the heat source 106 in the airflow direction.
The heat treatment using the heating furnace 100 is performed in the inner chamber 104 in a state where the cylindrical core body 110 having a coating formed on the outer peripheral surface is fixed on the heating table 112 so that the axial direction thereof coincides with the vertical direction. This is done in the arranged state. Thereby, the hot air blown out from the heat-resistant filter 108 is blown onto the coating formed on the outer peripheral surface of the cylindrical core 110.

In the heating process, when a heating furnace as described above is used, since the heating furnace is generally limited in size (internal volume) from the viewpoint of cost, a cylindrical core body with a coating formed on the outer peripheral surface is used. When putting in a heating furnace, putting in efficiently is calculated | required. Also from such a viewpoint, it is preferable that the cylindrical core is arranged in the heating furnace so that its axial direction is vertical and the density is as high as possible.
On the other hand, when placing the cylindrical core into the heating furnace, it is not only inconvenient to handle but also may fall over if it is placed directly in the heating furnace. Therefore, conventionally, as illustrated in FIG. 1, a cylindrical core body is placed on a heating table and placed in a heating furnace.

This heating table is a jig (cylindrical core handling jig) that is fixedly attached to the inner peripheral surface of the cylindrical core body in order to facilitate the handling of the cylindrical core body on the surface opposite to the bottom surface. This is provided with a recess that can be fitted to the shaft rod portion. The cylindrical core handling jig includes a fixing base that can be fixed to the inner peripheral side by contacting the inner peripheral surface of the cylindrical core, and the cylindrical core when the fixing base is fixed to the inner peripheral side. And a shaft bar attached to the fixed base so as to substantially coincide with the axial line of the body.
FIG. 14 is a schematic cross-sectional view showing a fixing method for fixing a cylindrical core body on a heating table in a conventional endless belt manufacturing method, in which 10 is a cylindrical core body, and 20 is a cylindrical core body handling. A jig, 22 is a fixing base, 24 is a shaft bar, 30 is a heating base, and 32 is a recess. At both ends of the cylindrical core body 10, a cylindrical core body handling jig 20 is disposed so as to contact the inner peripheral surface. The cylindrical core body handling jig 20 includes a fixing base 22 whose side surface portion is in contact with the inner peripheral surface of the cylindrical core body 10, and a hollow shaft rod 24 attached to the fixing base 22. The shaft rod 24 is attached to the inner peripheral surface of the cylindrical core body 10 so that a part of the shaft rod 24 protrudes from the opening of the cylindrical core body 10. Here, the cylindrical core body 10 is fixed on the heating table 30 by fitting the recess 32 provided on the upper surface side of the heating table 30 and the outer peripheral surface of the shaft rod 24.

  By using such a heating table, not only the handling of the cylindrical core is facilitated, but also it is easy to prevent overturning. However, even if a conventional heating table is used, the cylindrical core body sometimes falls. This is because it is necessary to make the length in the thickness direction smaller than the length in the bottom direction in order to ensure the stability of the heating table, so the shaft rod part of the cylindrical core handling jig inevitably This is because when the external force is applied to the cylindrical core body, the concave portion and the shaft rod are easily disengaged.

Therefore, as the heating base, it is possible to use a base and a projection provided on the surface opposite to the bottom surface of the base and having a convex portion that can be fitted to the shaft rod of the cylindrical core handling jig. preferable. If it is such a heating stand, the height of a convex part can be set so that it may correspond to the length of a shaft bar, ensuring the stability of a heating stand. In this case, even when an external force is applied to the cylindrical core body, the fitting between the convex portion and the shaft rod is difficult to come off. Note that the convex portion may be cylindrical or rod-shaped as long as it can be fitted to the shaft rod. For example, when the convex portion is cylindrical, the outer peripheral surface of the shaft rod of the cylindrical core handling jig and the inner peripheral surface of the cylindrical convex portion can be brought into contact with each other and fitted. In addition, if the shaft rod of the cylindrical core handling jig is cylindrical, a rod-shaped convex portion is used, and the inner peripheral surface of the cylindrical shaft rod and the outer peripheral surface of the rod-shaped convex portion are brought into contact with each other. can do.
FIG. 2 is a schematic cross-sectional view showing an example of a fixing method for fixing a cylindrical core body on a heating table, in which 34 is a heating table (base part), 36 is a convex part, and other symbols The parts shown are the same as those shown in FIG. In the example shown in FIG. 2, the cylindrical core body 10 is heated by using a heating table 34 provided with a projection 36 that can be fitted to the hollow portion of the shaft rod 24 at the center of the recess 32 of the heating table 30. It is fixed on the base 34.
On the other hand, when a jig as described above is not attached to the cylindrical core body, a heating table provided with a convex portion that can be fitted to the inner peripheral surface side and / or the outer peripheral surface side of the cylindrical core body may be used. Good. Such a heating table is preferably used when the diameter of the cylindrical core is 200 mm or less.

From the viewpoint of surely preventing the cylindrical core body fixed on the heating table from overturning and arranging the cylindrical core body at a high density in the heating furnace, the area of the bottom surface of the heating table is a cylinder. It is preferable that it is 1.5 to 2.5 times the sum total of the area of the end face and opening of the core. If the area of the bottom surface of the heating table is less than 1.5 times the sum of the area of the end face and the opening of the cylindrical core body, the cylindrical core body tends to overturn, and if it exceeds 2.5 times, the heating furnace In some cases, a large number of cylindrical cores cannot be arranged.
In addition, the shape of the bottom surface of the heating table is not particularly limited, and examples thereof include a triangle, a quadrangle, a circle, and a star shape. However, in any shape, the aspect ratio is 1: 1 from the viewpoint of preventing overturning. A close shape is preferred. For example, if the bottom surface is a triangle, a regular triangle is preferable, and if the bottom surface is a rectangle, a square is preferable. In addition, from the viewpoint of prevention of falling, the maximum length of the bottom surface (for example, if it is a triangle, the maximum length among three sides, if it is a polygon consisting of four or more sides, the maximum diagonal length, a perfect circle) The diameter of the cylindrical core is longer than the maximum length of the cylindrical core (the diameter of the cylindrical core is a perfect circle, and the length of the major axis is an ellipse). Larger is preferred.

On the other hand, the thickness (height in the direction orthogonal to the bottom surface) of the heating table is preferably about 1/80 to 1/5, and more preferably about 1/20 to 1/10 of the axial length of the cylindrical core. . If it is less than 1/80, the cylindrical core body may fall over with the heating table. If it exceeds 1/5, the cylindrical core body can be put into and out of the heating furnace while being fixed on the heating table. It may become difficult and workability may deteriorate.
On the other hand, the height in the heating furnace is preferably about 1.2 to 1.8 times the axial length of the cylindrical core, and the bottom area in the heating furnace is one heating table. The bottom area is preferably 1.5 to 9 times the bottom area.

  However, when the heating table as shown in FIG. 2 is used, the contact area with the cylindrical core handling jig is larger than that of the conventional heating table, so that heat easily escapes from the cylindrical core to the heating table. turn into. In such a case, in the axial direction of the cylindrical core body, the temperature in the vicinity of the heating table tends to decrease, and thus the heat treatment of the coating provided on the outer peripheral surface of the cylindrical core body is uneven, resulting in In some cases, resistance variation occurs in the width direction of the endless belt obtained, and in order to suppress resistance variation in the width direction, the margin in the width direction of the endless belt may be reduced.

In order to prevent such problems, (1) the flow of hot air near the heating table side of the cylindrical core body fixed to the heating table is improved, or (2) the heating table and the cylindrical core body are treated. It is effective to reduce the contact area with the tool or to reduce the thermal conductivity.
As a method of improving the flow of hot air near the heating table side of the cylindrical core body fixed to the heating table, in the case where hot air is blown from the upper side to the lower side of the cylindrical core body, It is preferable that the base has an opening that penetrates the bottom surface and a surface opposite to the bottom surface. Thereby, the airflow flowing along the outer peripheral surface of the cylindrical core body flows smoothly to the bottom surface side of the heating table without colliding with the base portion of the heating table and staying there. Temperature unevenness can be suppressed. Note that. In this case, it is necessary to arrange the heating table in a place such as a wire mesh where airflow is blown downward.

As a method of reducing the contact area between the heating table and the cylindrical core body handling jig or reducing the thermal conductivity, at least the portion of the heating table that contacts the cylindrical core body side has a thermal conductivity of 250 kcal. / Mhr ° C. or lower material (however, the lower limit value of the thermal conductivity is practically 25 kcal / mhr ° C. or higher), porous body, frame-shaped member, many minute projections provided on the surface of the heating table, and / or It is preferable to consist of a large number of minute recesses provided on the surface of the heating table. In addition to the above, it is preferable that at least a part of at least a part of the heating table that contacts the cylindrical core body is point contact and / or line contact.
In addition, "the part which contacts a cylindrical core body side" means the part which contacts a cylindrical core body handling jig, when using a cylindrical core body handling jig.

FIG. 3 is a schematic cross-sectional view showing another example of the fixing method for fixing the cylindrical core body on the heating table, and at least a part of the portion contacting the cylindrical core body side of the heating table is substantially This is a case of point contact and / or line contact. In the figure, 38 is a heating base (base portion), 40 is an auxiliary support portion (second convex portion), and is indicated by other symbols. The part is the same as that shown in FIG.
In the example shown in FIG. 3, the auxiliary support portion (the second support portion) that substantially makes point contact and / or line contact with the surface of the fixing base 22 on the side where the shaft rod 24 protrudes around the recess 32 of the heating base 38. The heating table 38 provided with a projection 40) is used. In this method, the height of the auxiliary support portion (second convex portion) 40 and the inner peripheral surface of the cylindrical core body 10 are set so that the end surface portion of the cylindrical core body 10 does not directly contact the upper surface portion of the heating table 38. Since the fixing position of the cylindrical core body handling jig to be attached is adjusted, the total contact area can be made smaller and the heat transfer path from the cylindrical core body 10 to the heating table 38 becomes longer. The heat transfer efficiency from the core 10 to the heating table 38 can also be reduced.
4 is a perspective view of the heating table shown in FIG. 3. FIG. 4 (1) shows the case where the auxiliary support portion (second convex portion) 40 is a ring-shaped member (member indicated by reference numeral 40A). FIG. 4B shows a case where the auxiliary support portion (second convex portion) 40 is a pin-shaped member (a member indicated by reference numeral 40B).

As described above, the uneven heating of the cylindrical core body in the axial direction can be suppressed by devising the shape of the heating table or the like, but in addition to this, the cylindrical shape disposed in the heating furnace This can also be handled by adjusting the position of the core.
Generally, since the temperature in the heating furnace increases as it goes upward, it is preferable to dispose the cylindrical core at the top of the heating furnace. As such a method, there is a method of placing the cylindrical core on a thick heating table, but the cylindrical core may be suspended from the upper part of the heating furnace.
FIG. 5 is a schematic view showing an example in which the cylindrical core is suspended from the upper part of the heating furnace, and is a view of the cylindrical core suspended from the upper part of the heating furnace as viewed from the side. In the figure, 50 is a hook, 52 is an eye nut, and the other symbols are the same as those shown in FIG.
As shown in FIG. 5, the cylindrical core 10 has a hook 50 with one end fixed to the upper part of a heating furnace (not shown), and the surface of the fixing base 22 of the cylindrical core handling jig 20 (not shown). It is suspended from the upper part of the heating furnace by being connected through an eyenut 52 attached to the heating furnace.

Next, the drying process performed before a heating process is demonstrated.
In the drying step, a film is formed by applying a film-forming resin solution containing a solvent to dry the coating film formed on the outer peripheral surface of the cylindrical core. Although there is no particular limitation on the drying method and drying conditions of the coating film formed on the outer peripheral surface of the cylindrical core body, in practice, the cylindrical core body with the coating film formed on the outer peripheral surface is used as a drying table. After fixing, it is performed by placing and heating in a drying furnace in which the inside of the furnace is heated to 50 ° C. or higher in advance. This is to facilitate the handling of the operator when the cylindrical core is large to some extent.
However, as compared with the case where only the cylindrical core body with the coating film formed on the outer peripheral surface is disposed in the drying furnace, the cylindrical core body with the coating film formed on the outer peripheral surface is fixedly disposed on the drying table. In addition to the cylindrical core, heating of the drying table is also required. For this reason, even if the inside of the drying furnace is preheated to a temperature necessary for the drying process, the temperature in the furnace is lowered, the temperature of the cylindrical core body is hardly increased, and the time required for the drying process is increased. . Therefore, productivity is reduced.

In order to prevent such a decrease in productivity, before fixing the cylindrical core body having the coating film formed on the outer peripheral surface to the drying table, the drying table is set at 50 ° C. to the furnace temperature of the drying furnace. It is preferable to pre-heat at a temperature within the range. By such pre-heating of the drying table, the time required for the drying process can be shortened, and the productivity can be prevented from decreasing.
In addition, if the pre-heat treatment temperature of a drying stand is less than 50 degreeC, the temperature in a drying furnace will fall easily and the time which a drying process requires may become long. In addition, when the preheat treatment temperature of the drying table exceeds the furnace temperature of the drying furnace, the temperature balance in the drying furnace is lost, or the temperature of the drying table is too high. Carry-in work may be difficult.

In addition, although heating means other than a drying furnace may be used for the preheat treatment of the drying table, it is preferable to use a drying furnace. Thereby, a drying stand can be pre-heat-treated in the range which does not exceed the temperature in a drying furnace.
In addition, after the drying process is finished, the drying table taken out from the drying furnace is fixed in a state where the cylindrical core body having the film formed on the outer peripheral surface is fixed before the temperature of the drying table is cooled to less than 50 ° C. It is preferable to remove the cylindrical core body with the coating formed on the outer peripheral surface, fix the cylindrical core body with the coating film formed on the outer peripheral surface, and place it again in the drying furnace. As a result, the drying process can be carried out continuously without wasting the heat energy of the drying table once heated in the drying furnace.

Next, the drying table used in the present invention and the method of rotating the cylindrical core will be described. FIG. 6 is a schematic diagram showing an example of a drying table. FIG. 6 (1) is a view of a cylindrical core body fixed on the drying table viewed from the side, and FIG. 6 (2) is a drying table. The figure which looked at the cylindrical core fixed on top from the end surface side is shown. In the figure, 200 is a drying table, 202 is a base, 204 is a fixing member, 210 is a cylindrical core, and 212 is a shaft bar.
The drying table 200 includes a base 202 and fixing members 204 provided at both ends of the upper surface of the base 202, and a bearing portion for hooking and receiving the shaft rod 212 is provided on the upper portion of the fixing member 204. The cylindrical core body 210 is fixed to the drying table 200 with a shaft rod 212 of a cylindrical core body handling jig (parts other than the shaft rod not shown) provided at both ends of the inner peripheral surface of the cylindrical core body 210. Is performed by being hooked on the bearing portion of the fixing member 204. Here, the cylindrical core handling jig is the same as that shown in FIG. The cylindrical core handling jig used in the drying step can be the same as that used in the heating step, but is not limited thereto. Moreover, you may fix a cylindrical core body to a drying stand without going through a cylindrical core body handling jig by devising the shape of a fixing member. For example, it is also possible to fix the cylindrical core body on the drying table by attaching a shaft bar parallel to the base to the fixing member and hooking the shaft rod through the inside of the cylindrical core body.

In addition, it is possible to rotate a cylindrical core body to the circumferential direction by using the drying stand which has a bearing part as shown in FIG. By utilizing this, after the cylindrical core body after the coating film is formed is fixed to the drying table, the cylindrical core body is rotated until the drying process in the drying furnace is finished, and the coating film droops. Occurrence can also be prevented. Here, the rotation of the cylindrical core body is preferably performed at a speed of 2 to 20 rpm with respect to the circumferential direction in a state where the cylindrical core body is fixed to the drying table so that the rotation axis thereof coincides with the horizontal direction. It is. If it is less than 2 rpm, the rotation is slow, so that dripping tends to occur. If it exceeds 20 rpm, the coating film may be uneven.
The rotation of the cylindrical core body 210 fixed to the drying table 200 as illustrated in FIG. 6 is applied to the shaft 212 part of the cylindrical core body handling jig provided at both ends of the inner peripheral surface of the cylindrical core body 210. On the other hand, it can be performed by transmitting a driving force via a chain, a gear or the like.

  FIG. 7 is a schematic diagram showing an example of a method for rotating the cylindrical core, and shows a state where the cylindrical core fixed to the drying table shown in FIG. 6 is rotated. . In addition, in FIG. 7, the state which looked at the cylindrical core fixed to the drying stand from the end surface side as shown in FIG. 6 (2) is shown. In the figure, 220, 222, 224, 226, 228 are gears, 230, 232, 234 are chains, 236 is a support roll, 238 is a drive roll, and the other symbols are the same as those shown in FIG. .

In FIG. 7, a support roll 236, a drive roll 238 connected to a motor (not shown), and a chain 234 stretched between these two rolls 236 and 238 are provided below the drying table 200. The chain 234 can be rotated in either direction, and the rotational movement of the chain 234 is caused by a shaft rod through a driving force transmission portion composed of a plurality of small gears and chains denoted by reference numerals 220 to 232 in the drawing. 212, the cylindrical core body 210 can be rotated in either direction.
The driving force transmission portion is fitted to the shaft rod 212, and two gears 220 and 222 arranged at a position of about 90 degrees with respect to the shaft rod 212, and a gear 224 fitted to the two gears. , A chain 230 that drives the gear 224, a gear 226 that is arranged so as to stretch the chain 230 together with the gear 224, a gear 228 that fits the chain 234, and a chain that is stretched by the gear 226 and the gear 228. 232. The shaft rod 212 is provided with a groove so that it can be engaged with the gears 220 and 222. The driving force transmission unit may be disposed on the side of the fixing member 204 where the cylindrical core body 210 is provided, or may be disposed on the side of the fixing member 204 opposite to the side where the cylindrical core body 210 is provided. Good. Moreover, it is preferable that the driving force transmission unit (mechanism for rotating the cylindrical core body) is provided integrally with the drying table 200. Note that the configuration of the driving force transmission unit is not limited to the configuration shown in FIG. 7, as long as the rotational motion of the chain 234 can be transmitted as the rotational motion of the cylindrical core body 210. It is not particularly limited.

  In order to rotate the cylindrical core in the drying furnace, a lower part of the drying furnace includes a driving roll 238 connected to a motor (not shown) and a chain 234 stretched between the two rolls 236 and 238. A driving device may be arranged, and a drying table provided with a driving force transmission unit may be used so that the driving force of the chain 234 is transmitted during the drying process.

Next, a drying furnace used for drying the coating film formed on the outer peripheral surface of the cylindrical core fixed to the drying table will be described with reference to the drawings.
FIG. 8 is a schematic diagram showing an example of a drying furnace used in the endless belt manufacturing method of the present invention, and shows a view of the drying furnace as seen from the side so that the structure inside the drying furnace can be grasped. is there. In the figure, 240 is a drying furnace, 242 is a rail, 244 and 246 are doors, 248 is a housing, and other symbols are the same as those shown in FIG.
The drying furnace 240 includes a housing 248, doors 244 and doors 246 provided on each side of the housing 248, and rails provided inside and outside the housing 248 so as to penetrate the doors 244 and door 246. 242. In the drying process, the drying table 200 to which the cylindrical core body 210 is fixed is placed on the rail 242 and is carried into the housing 248 from the door 244 side. The formed coating film is dried. When the drying process is completed, the drying table 200 to which the cylindrical core body 210 is fixed is transferred from the door 246 side to the outside of the housing 248 by moving on the rail 242.
Here, in the example shown in FIG. 8, three drying stands can be arranged in the housing 248, but the size of the drying furnace, the cylindrical core body to be dried, and this are fixed. The number of drying tables arranged in the housing 248 varies depending on the size of the drying table.

In the present invention, for example, when a drying table as shown in FIG. 6 is used, both ends of the cylindrical core body are lower than the central portion, resulting in temperature variations in the axial direction of the cylindrical core body. In some cases, the resulting endless belt has a variation in surface resistivity in the width direction. Such a problem is not related to the shape or configuration of the drying table, but the portion where the cylindrical core body and the drying table are in direct contact or indirectly (through the cylindrical core body handling jig etc.) and the other portion are not. Is fundamentally unavoidable.
On the other hand, in the present invention, as described above, from the viewpoint of productivity and thermal efficiency, it is preferable to pre-heat the drying table to a temperature within the range of 50 ° C. to the furnace temperature of the drying furnace. From the viewpoint of suppressing such temperature variation, it is more preferable to adjust the drying table to a range of the furnace temperature of the drying furnace from -70 ° C to the furnace temperature of the drying furnace. When the preheat treatment temperature of the drying table is lower than the in-furnace temperature of the drying furnace -70 ° C., the temperature variation of the cylindrical core increases, and the surface resistance variation in the surface of the endless belt obtained increases. There is.

Further, the drying table used in the present invention is not particularly limited as long as it includes one or more fixing members for fixing the cylindrical core as illustrated in FIG. It is preferable that at least any one fixing member can be deformed and / or moved on the drying table (base portion) in accordance with the axial length of the cylindrical core so that the core can be fixed. .
For example, in the example shown in FIG. 6, it is preferable that any one of the fixing members 204 is movable on the base 202 so as to be movable in the axial direction of the cylindrical core body 210.
FIG. 9 is a schematic diagram showing another example of the drying table, and basically shows the drying table having the configuration shown in FIG. 6 as seen from above with the cylindrical core body fixed. FIG. 9 (1) and FIG. 9 (2) are views showing the positions of the fixing members when the cylindrical cores having different axial lengths are fixed.
In the figure, 210A represents a cylindrical core body, 210B represents a cylindrical core body (a cylindrical core body having a smaller axial length than the cylindrical core body 210A), 204A represents a fixing member, and 204B represents a sliding type fixing member. The other symbols are the same as those shown in FIG.

As shown in FIG. 9, one of the two fixing members 204A and 204B (204B) can be slid with respect to the axial direction when the cylindrical core body is fixed. For this reason, when the axial length of the cylindrical core 210B is short (FIG. 9 (2)), when the axial length of the cylindrical core 210A is long (FIG. 9 (1)), The fixing member 204B can be moved from the dotted line position (the position where the fixing member 204B is disposed in FIG. 9A) to the solid line side position (a position closer to the fixing member 204A than the dotted line position). . Thus, by making the fixing member movable, it is possible to deal with various cylindrical cores having different axial lengths.
In addition, in the case where the shaft core parallel to the base is attached to the fixing member and the cylindrical core is fixed on the drying table by hooking the shaft rod through the inside of the cylindrical core, the length of the shaft rod portion The height may be changed.

Moreover, in the drying process using the drying table, it is common to dry the air heated to a predetermined temperature from the upper side of the drying table by spraying it on the coating film formed on the outer peripheral surface of the cylindrical core. For this reason, it is particularly preferable that a vent hole is provided in the base portion of the drying table so that the airflow smoothly flows from the upper part to the lower part of the drying table. In this case, the drying table is arranged on a wire net or the like so as to secure a space for blowing air to the lower part during the drying process.
When a coating film formed on the outer peripheral surface of various cylindrical cores having different axial lengths is dried using a drying table provided with such a vent hole, symmetry is as much as possible with respect to the vent hole. It is preferable to arrange the cylindrical core so as to be higher. Thereby, the variation in the speed of the air current blown to the outer peripheral surface of the cylindrical core and the variation in the wind velocity can be reduced, and the resulting surface resistance variation in the endless belt can be suppressed. For that purpose, as described above, any one of the fixing members may use a drying table that can be deformed and / or moved on the drying table (base part) according to the axial length of the cylindrical core body. Is preferred. For example, in the example shown in FIG. 9, not only the fixing member 204B but also the fixing member 204A is slidable with respect to the axial direction when the cylindrical core body is fixed. Regardless of the axial length, it is possible to fix the cylindrical core body to the drying table so as to be highly symmetric with respect to the vent hole.

FIG. 10 is a schematic diagram showing another example of the drying table, which basically shows a case where two ventilation holes are provided in the base portion of the drying table having the configuration shown in FIG. FIGS. 10A and 10B are views showing a state in which the fixing position of the cylindrical core body having the same axial length is changed.
In the figure, reference numeral 206 denotes an air vent hole, 210C denotes a cylindrical core, and the other symbols are the same as those shown in FIG. 9, but in the example shown in FIG. 10, the fixing member 204A is also the fixing member 204B. Like the slide type.
In the example shown in FIG. 10, two air vent holes 206 of the same size are provided between the two fixing members 204 </ b> A and 204 </ b> B provided at both ends of the base 202, and the shaft when the cylindrical core body 210 </ b> C is fixed. It is arranged in series with respect to the direction. Here, when the cylindrical core 210C is fixed, only the fixing member 204B may be moved from the dotted line position to the solid line position and fixed as shown in FIG. 10 (1). Since the body 210C is fixed at an asymmetrical position with respect to the two air holes 206 in the axial direction, the body 210C is not so preferable for the reason described above.
Therefore, as shown in FIG. 10 (2), not only the fixing member 204B but also the fixing member A is used to fix the cylindrical core 210C at a position symmetrical to the two air holes 206 in the axial direction. It can be said that it is preferable to move from the dotted line position to the solid line position.

-Solvent recovery method-
In the drying process and the heating process as described above, the solvent is volatilized from the coating film or film. Gases containing solvents generated during the manufacture of such endless belts are usually not subject to legal regulations, and as long as there is no voluntary regulation on the part of operators, they are kept in the atmosphere as they are to reduce facility costs. Has been released. Further, even when the business operator performs self-regulation, the solvent is released to the atmosphere without collecting it so as to reduce the facility cost if it is less than the set regulation value.
On the other hand, the film-forming resin solution used for forming the coating film on the outer peripheral surface of the cylindrical core body uses a water-soluble solvent having a boiling point of more than 100 ° C. as the solvent, and the drying process has a furnace temperature of A heating furnace in which a heating process is performed by placing a cylindrical core body having a coating film formed on the outer peripheral surface thereof in a drying furnace maintained at 50 ° C. or higher, and the furnace temperature is maintained at 250 ° C. or higher. Generally, it is carried out by arranging a cylindrical core body in which a coating is formed on the outer peripheral surface.
In an endless belt manufacturing facility comprising such a drying furnace or heating furnace, a gas containing a solvent volatilized from the coating film in the drying furnace or a gas containing a solvent volatilized from the film in the heating furnace Or exhausted outside the furnace, that is, into the atmosphere.
However, from the viewpoint of environmental considerations and effective use of resources, it is preferable to collect the gas containing the solvent that has been exhausted into the atmosphere.

The recovery method in this case is not particularly limited, but the gas containing the solvent discharged from the heating furnace and / or the drying furnace is passed through a heat exchanger having a heat transfer wall temperature of 40 ° C. or less. Therefore, it is preferable that the solvent is liquefied and recovered from the gas containing the solvent.
Further, it is preferable that the gas containing the solvent discharged from the heating furnace and / or the drying furnace is passed through a heat exchanger and then passed through a wet packed tower using water to dissolve and recover the solvent in water. . As described above, the primary recovery using the heat exchanger and the solvent component in the gas that could not be recovered by the heat exchanger can be secondary recovered using the wet packed tower. In addition, these methods have an advantage that not only the solvent can be efficiently recovered, but also the equipment cost required for recovering the solvent component can be kept low.
Although it depends on the type of solvent and the solvent concentration in the gas containing the solvent discharged from the heating furnace and / or drying furnace, it is possible to recover several tens of percent of the solvent during the primary recovery. About 90% of the solvent can be recovered.

FIG. 11 is a schematic diagram showing an example of equipment for recovering a gas containing a solvent discharged from a heating furnace or a drying furnace used in the endless belt manufacturing method of the present invention, in which 300 and 302 are heat exchangers. , 304 is an exhaust duct, 306 is an exhaust fan, 308 is a wet packed tower, and the devices denoted by other reference numerals are the same as those shown in FIGS.
One end of the drying furnace 240 and the heating furnace 100 is connected to the intake port side of the exhaust fan 306, and is connected to the other end of the exhaust duct 304 that is bifurcated in the middle. A heat exchanger 300 and a heat exchanger 302 are disposed in the exhaust duct 304 between the drying furnace 240 and the heating furnace 100, respectively. Further, the exhaust port side of the exhaust fan 306 is connected to the wet packed tower 308.

Here, the gas containing the solvent discharged from the drying furnace 240 passes through the heat exchanger 300 disposed in the middle of the exhaust duct 304, and the gas containing the solvent discharged from the heating furnace 100 passes through the exhaust duct 304. When passing through the heat exchanger 302 disposed on the way, the heat exchangers 300 and 302 are contacted with the heat transfer walls to be cooled and condensed to liquefy the solvent. As a result, the solvent is recovered. In addition, the gas that has passed through the heat exchangers 300 and 302 is carried to the exhaust fan 306 by the exhaust duct 304.
The heat transfer wall temperature of the heat exchanger is preferably 40 ° C. or lower. If the temperature exceeds 40 ° C., the solvent recovery performance decreases, which is not preferable. The type of heat exchanger is preferably a water-cooled type from the viewpoint of solvent recovery performance and facility cost reduction.

  The gas that has passed through the heat exchangers 300 and 302 may contain a trace amount of solvent gas that could not be recovered by the heat exchangers 300 and 302. In order to recover this trace amount of solvent gas, it can be recovered by passing it through a wet packed tower 308 connected to an exhaust fan 306 and dissolving the solvent in water.

The wet packed tower 308 is not particularly limited as long as it is a known wet packed tower using water. For example, a wet packed tower having a configuration shown in FIG. 12 can be used.
FIG. 12 is a schematic diagram showing an example of a wet packed tower used in the endless belt manufacturing method of the present invention, in which 310 is a tower, 312 is packed, 314 is a water tank, 316 is a pump, and 318 is water supply. Piping, 320 is a gas inlet, 322 is a gas outlet, and the other symbols are the same devices as those shown in FIG.

  The main part of the wet packed tower 308 includes a tower 310 and a water tank 314 connected to the lower side of the tower 310. Most parts except the upper part of the column 310 are filled with a packing 312 for increasing the efficiency of gas-liquid contact, and a gas outlet 322 is provided at the top of the column 310. The water tank 314 is filled with water, and a gas inlet 320 is provided at a position higher than the liquid level. The gas inlet 320 is connected to the exhaust port side of an exhaust fan 306 (not shown). Further, a water supply pipe 318 having one end located below the liquid level of the water tank 314 and the other end located above the tower 310 is provided so that the water in the water tank 314 can be supplied to the upper part of the tower 310. . A pump 316 for supplying water in the water tank 314 to the upper portion of the tower 310 is connected to the water supply pipe 318. The water supply pipe 318 located in the upper part of the tower 310 is a shower nozzle so that water can be supplied evenly to the packing 312. As a result, water flows in a thin film on the surface of each filling, and gas-liquid contact can be performed efficiently.

  The recovery of the solvent by the wet packed tower 308 is a thin film on the surface of each packing when the gas containing the solvent supplied from the gas inlet 320 rises in the tower 310 filled with the packing 312. This is accomplished by causing the solvent to be absorbed by the water by causing gas-liquid contact with the flowing water. The gas from which the solvent has been removed is discharged from a gas outlet 322 provided at the top of the tower 310. In this method, since the solvent is accumulated in the water, it is necessary to exchange the water periodically.

  The endless belt manufacturing method of the present invention has been described in detail for each step. Next, the endless belt manufacturing method is used for other steps other than the drying step, the heating step, or the solvent recovery step, and for manufacturing the endless belt. Explains various materials and outlines the endless belt manufacturing process step by step.

.
[1] Coating method of film-forming resin solution:
In manufacturing the endless belt, first, a film-forming resin solution is applied to the surface of the cylindrical core. As a film-forming resin, PI resin is coated with a precursor solution, the solvent is heated and dried, and then subjected to a dehydration condensation reaction to obtain a film.

  PI precursor comprises acid dianhydride and diamine, N-methyl-2-pyrrolidone (boiling point: 202 ° C.), N, N-dimethylacetamide (boiling point: 166.1 ° C.), acetamide (boiling point: 222.15). ° C), etc., can be obtained by a condensation reaction in an aprotic polar solvent (water-soluble solvent).

  Representative examples of acid dianhydrides include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Products, 2,2-bis (3,4-dicarboxyphenyl) ether dianhydride, and the like.

  The diamine component is paraphenylenediamine, metaphenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminophenylmethane, benzidine, 3,3′-dimethoxybenzidine, 3,3′-diaminobenzophenone, 4,4. It is selected from one or more of '-diaminodiphenylpropane, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane and the like.

  On the other hand, PAI resins are acid anhydrides such as trimellitic anhydride, ethylene glycol bisanhydro trimellitate, propylene glycol bisanhydro trimellitate, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, 3, It can be obtained by combining 3 ', 4,4'-biphenyltetracarboxylic acid anhydride and the like with the above diamine and performing polycondensation reaction in an equimolar amount. Since the PAI resin has an amide group, it easily dissolves in the solvent even if the imidization reaction proceeds. Therefore, the PAI resin is preferably 100% imidized.

  The concentration, viscosity, and the like of the film-forming resin solution are selected as appropriate, but the solid content concentration of the solution is preferably 10 to 40% by mass and the viscosity is 1 to 1000 Pa · s.

When an endless belt is used as a photoreceptor or a transfer belt, conductive particles are dispersed in a solution in order to impart conductivity. Examples of the conductive particles include carbon black, carbon-based materials such as carbon beads obtained by granulating carbon black, carbon fiber, and graphite; metals or alloys such as copper, silver, and aluminum; tin oxide, indium oxide, antimony oxide, Examples thereof include conductive metal oxides such as SnO ₂ · In ₂ O ₃ composite oxide.

  The cylindrical core is preferably a cylinder made of metal such as aluminum, stainless steel, or nickel. The length of the cylindrical core is required to be equal to or longer than the target endless belt, and when a plurality of endless belts are manufactured at the same time, a length equal to or more than the number is required. Further, in order to secure a margin for the invalid area generated at the end, it is desirable that the length is about 10 to 40% longer than the target length. The outer diameter of the cylindrical core body is adjusted to the diameter of the target endless belt, and the thickness is set to a thickness that can maintain the strength of the core body.

  In order to prevent the film to be formed from adhering to the surface of the cylindrical core body, the surface of the cylindrical core body is given releasability. There are methods of covering the surface of the cylindrical core with a fluororesin or silicone resin or applying a release agent to the surface.

  Note that when PI is imidized, there is evaporation of the solvent and water generated during the reaction, and the film after the reaction may partially swell, particularly when the film thickness exceeds 50 μm. In order to prevent this swelling, it is preferable to roughen the surface of the cylindrical core as disclosed in JP-A-2002-160239. As the method, there are methods such as blasting, cutting, sandpaper peeling, etc., and the surface roughness is preferably about Ra 0.2 to 2 μm. Thereby, the gas generated from the film can go out through a slight gap formed between the cylindrical core and the film, and does not swell.

Although the application | coating method of the film formation resin solution to a cylindrical core body is arbitrary, an example of a preferable application | coating method is demonstrated.
FIG. 13 is a schematic cross-sectional view of the coating apparatus during coating. However, only the main part of the coating is shown, and the peripheral parts such as the lifting and lowering means for the core body are omitted. In the present specification, “apply on the core” means that the coating liquid is applied on the surface of the core and, if the surface has a layer, on the layer. Further, “raising the core” is a relative relationship with the liquid level, and includes the case of “stopping the core and lowering the coating liquid level”.

  In FIG. 13, when the solution 2 is put into the annular application tank 7 and passed through the cylindrical core body 10 from the lower part to the upper part, the coating film 4 is formed and application is performed. Another cylindrical core body 11 is stacked under the cylindrical core body 10. A sealing material 8 is attached to the bottom of the annular coating tank 7 so that the solution does not leak. The sealing material is made of a flexible plate material such as polyethylene, silicone rubber, or fluorine resin. On the solution 2, an annular body 5 provided with a circular hole 6 larger than the outer peripheral outer diameter of the cross section of the cylindrical core body 10 is installed in a freely movable state.

  The annular body 5 is floated on the solution during application. However, when the buoyancy is insufficient at rest, the annular body 5 is supported on the outer peripheral surface of the annular body 5 or on the application tank to prevent the annular body from sinking. Arms may be provided.

  As shown in FIG. 13, the shape of the inner wall of the circular hole 6 provided in the annular body 5 is an oblique straight line as long as the gap between the cylindrical core body 10 is wide at the lower part immersed in the solution 2 and the upper part is narrow. In addition to the shape, a stepped shape or a curved shape may be used. The gap between the outer diameter of the cylindrical core body 10 and the inner diameter of the circular hole 6 (the minimum inner diameter when the inner diameter changes stepwise or continuously) is adjusted in view of the desired coating thickness.

  At the time of application, the film thickness of the coating film 4 is adjusted by the gap between the cylindrical core 10 and the circular hole 6. The rising speed of the cylindrical core body 10 is preferably about 0.1 to 1.5 m / min. When the cylindrical core body 10 is lifted through the circular hole 6, the cylindrical core body 10 is interposed by the solution 2. A frictional resistance is generated in the gap between the annular body 5 and the annular body 5 is lifted.

  When the annular body 5 is lifted in this way, the annular body 5 moves in the horizontal direction so that the frictional resistance with the cylindrical core body 10 is constant in the circumferential direction, and the gap is constant in the circumferential direction. Therefore, the annular body 5 does not come into contact with the cylindrical core body 10, and a constant gap is always maintained.

[2] Endless belt drying method:
After the application is completed, the cylindrical core body is taken out, fixed to a drying table as shown in FIG. 6, for example, and rotated so that the axial direction of the cylindrical core body is horizontal so that the coating film does not hang downward. The cylindrical core can be rotated as shown in FIG.

Next, the coating film is dried by placing a drying table having a cylindrical core fixed in a drying furnace as shown in FIG. A filter is preferably provided at the air outlet of the drying furnace. In addition, since a drying process is not performed at the temperature exceeding 250 degreeC, a general HEPA filter etc. can be used as a filter, However, You may use the HEPA filter which has 250 degreeC or more heat resistance.
The drying conditions are preferably set so that the residual solvent contained in the coated film after drying is about 30 to 50% by weight, the temperature is preferably 100 to 200 ° C., and the time is preferably about 10 to 60 minutes. In order to accelerate the drying of the solvent, air heated to about 100 to 200 ° C. may be blown onto the surface of the coating film.

[3] Endless belt heating method:
After drying, the cylindrical core is removed from the drying furnace. Although it may be put in the heating furnace as it is, if it is arranged in the heating furnace with the axial direction of the cylindrical core being horizontal, many cylindrical cores cannot be processed at one time. It is preferable to place a cylindrical core body on a heating table that can be placed vertically as shown.

Next, as shown in FIG. 1, the cylindrical core body fixed to the heating table is placed in a heating furnace and subjected to heat treatment.
Here, when the film forming resin is PI, the heating temperature is generally about 250 to 400 ° C, preferably about 300 to 350 ° C. Since the imidization reaction is difficult to complete unless the temperature is 250 ° C. or higher, it is preferably placed at a temperature of 250 ° C. for 2 hours or longer, and more preferably at a temperature of 300 ° C. or higher for 1 hour or longer.
Further, when the film-forming resin is PAI, there is no reaction, but in order to completely dry the residual solvent, it is usually heated to 220 to 320 ° C, preferably about 250 to 300 ° C.

  After cooling, the cylindrical core is taken out, and the formed film is peeled from the cylindrical core to obtain an endless belt. The endless belt may be cut to a predetermined length by cutting an unnecessary portion of the end, and may be subjected to drilling or ribbing as necessary.

When an endless belt is used as the transfer belt, the thickness is preferably 75 to 85 μm. The resistance value is preferably about 10 ⁷ to 10 ¹³ Ωcm in terms of volume resistivity and about 10 ⁸ to 10 ¹³ Ω / □ in terms of surface resistivity, but the variation ranges from one digit or less to the central value. Should be within.

Example 1
The surface of the aluminum cylinder having an outer diameter of 366 mm and a length of 900 mm was roughened to Ra 0.4 μm by blasting with spherical alumina particles. A silicone release agent (trade name: Sepacoat, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface to obtain a cylindrical core.
In addition, on the inner peripheral surfaces of both ends of the cylindrical core body, a cylindrical core body handling jig comprising an aluminum fixing base and a shaft rod with a diameter of 30 mm is provided in order to facilitate fixing to a drying table or a heating table. Attached. The total weight of the cylindrical core was 65 kg.
On the other hand, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether were used in N-methyl-2-pyrrolidone (boiling point: water-soluble solvent at 202 ° C.) and the like. A solution of the PI precursor subjected to molar reaction was prepared. The concentration is 20% by mass and the viscosity is about 40 Pa · s. Carbon black (trade name: Special Black 4, manufactured by Degussa Huls Co., Ltd.) was mixed with the solution at a solid content mass ratio of 23%, and then dispersed with an opposing collision type disperser for 2 hours to obtain a coating solution.

Next, the coating film was formed in the cylindrical core body surface using the cyclic | annular application | coating apparatus which has a structure shown in FIG. The annular coating device used was a 0.5 mm thick rigid polyethylene having a hole with an inner diameter of 386 mm in the bottom surface of the annular coating tank 7 having an inner diameter of 500 mm and an inner height of 80 mm, and a bottom surface with a hole with an inner diameter of 362 mm. An annular sealing material 8 made of was attached. Also, an aluminum annular body 5 having an outer diameter of 420 mm, a minimum inner diameter of 367.2 mm, and a height of 50 mm was produced. The inner wall was an inclined surface, and the inclination angle with respect to the vertical line was 5 °. Here, the roundness of the minimum inner diameter portion was 15 μm. Three arms were attached to the side surface of the annular body at equal intervals and installed in the annular coating tank 7.
Next, the two cylindrical core bodies 10 and 11 were attached to the annular coating tank 7, the coating liquid was added, and the cylindrical core body 10 was raised at a speed of 0.7 m / min. About 20 mm was lifted from the liquid level, and the height of the annular body increased as the cylindrical core body 10 rose. Therefore, the speed was gradually reduced, and when the cylindrical core body 10 was raised about 60 mm, the rising speed of the cylindrical core body 10 was made constant at a place where the height of the annular body was about 30 mm. The speed at that time was 0.6 m / min.

The annular body did not contact the core body while the cylindrical core body 10 was rising, and after coating, the coating film 4 having a wet film thickness of about 600 μm was formed on the outer peripheral surface of the cylindrical core body 10.
Thereafter, the axial direction of the cylindrical core body was made horizontal within 3 minutes and placed on a drying table having a configuration as shown in FIG. In addition, as shown in FIG. 7, the drying table is provided with a driving force transmission unit including a plurality of gears and a chain that rotate the cylindrical core body by the chain 234.
Note that a drying furnace having the configuration shown in FIG. 8 was used. However, a driving device comprising a driving roll 238 connected to a motor as shown in FIG. 7 and a chain 234 stretched between these two rolls 236 and 238 is provided below the rail 242 of the drying furnace. Is arranged, and by arranging the drying table on the rail 242, the cylindrical core fixed to the drying table can be rotated.

  Next, the cylindrical core placed on the drying table was sequentially put into a drying furnace set at 150 ° C. every 10 minutes while rotating at 6 rpm. In the drying furnace, hot air blows off from above at a speed of about 1 m / sec and hits the cylindrical core. After 30 minutes, the core was taken out. At this time, foreign matter on the surface of the film was observed, and on average, about three fine foreign matters were mixed per piece.

  Next, the cylindrical core was placed vertically and placed on a heating table as shown in FIG. 2, and four cylindrical cores were placed in the heating furnace to perform heat treatment. A heating furnace having the configuration shown in FIG. 1 was used. This furnace has a width of 1400 mm, depth of 1400 mm, height of 1600 mm, and a semi-HEPA filter (made by Nippon Mining Co., Ltd., trade name: Atmos heat-resistant 500 ° C.) at the top of the inner chamber. Four HEPA filters GCW, dust collection capacity: 0.5 to 1 μm particle collection efficiency of 90% or more, width 610 mm, depth 610 mm, height 150 mm) are attached. However, this heating furnace is not a complete circulation system, and it is also possible to take in air outside the heating furnace while partially discharging the air in the heating furnace.

During the heat treatment, the wind speed blown from the heat-resistant filter was set to about 1.5 m / sec. The number of particles of 0.5 μm or more in the hot air blown from the heat resistant filter at this time was 3500 / m ³ . Next, out of the circulating air, 5 m ³ / min of air is discharged outside the heating furnace. Instead, 5 m ³ / min of air outside the heating furnace is taken in, and the solvent gas concentration in the inner chamber is 0.5 vol% or less. It was made to become the state of.

As heating conditions, the temperature was raised from room temperature to 300 ° C. in 2 hours, held at 300 ° C. for 1 hour and 20 minutes, and cooled to room temperature in 1 hour and 40 minutes.
After cooling to room temperature, the cylindrical core was removed from the heating furnace, and the coating was peeled off from the cylindrical core, thereby obtaining an endless belt made of PI resin. Almost all of the minute foreign matters on the surface after drying were almost completely removed depending on whether they were decomposed or shrunk by high heat, and there was no new adhesion.

  When the film thickness of the endless belt was measured, it was uniform at 80 μm except for 30 mm from the upper end. Two belts were obtained by cutting the endless belt by 369 mm in width. Although this belt was used as a transfer belt of an image forming apparatus (DocuCentre C6550I) manufactured by Fuji Xerox Co., Ltd., image formation was performed, but no image defect occurred.

(Comparative Example 1)
In Example 1, an endless belt was produced in the same manner as in Example 1 except that a heating furnace having no heat-resistant filter was used. The number of particles of 0.5 μm or more in the hot air used at this time was 200,000 particles / m ³ .
As a result, on the surface of the obtained endless belt, on the average, about 4 fine foreign matters were adhered per one. Among them, about 80% could be removed by rubbing with waste, but the remaining one could not be removed and adhered firmly, and it was a level that was recognized as a defective product. This is thought to be because the dust that exists in the air in the heating furnace (which is already in a state that can withstand high temperatures) adheres to the film and is embedded in the surface of the film due to high-temperature heat, and thus cannot be removed. .
Further, as described above, when a belt certified as a defective product was attached and evaluated as a transfer belt of the image forming apparatus, an image defect due to the transfer belt was observed.

-Effect of heating table-
The heating table used in Example 1 (hereinafter referred to as “heating table A1”) is made of SUS304 member, and the size of the base part is 500 mm long, 500 mm wide, and 170 mm high. A cylindrical convex portion having an outer diameter of 50 mm, an inner diameter of 30 mm, and a height of 100 mm is provided at the center of the upper surface of the heating table. The inner diameter of the convex portion is slightly smaller than the diameter (30 mm) of the shaft rod so that it can be fitted with the shaft rod, and the shaft rod of the cylindrical core is fitted on the inner peripheral surface side of the tip of the convex portion. Tapered to make it easier to fit.
In place of the heating table A1, a conventional heating table as shown in FIG. 14 (the size of the base portion is 500 mm long, 500 mm wide, 170 mm high, and the diameter of the recess is 30 mm (slightly so that it can be fitted to the shaft rod). When a depth of 30 mm) is used, the workability deteriorates when the cylindrical core body is taken in and out of the heating furnace, and the cylindrical core body sometimes falls over.

In addition, with the cylindrical core body fixed on the heating base A1, thermocouples are attached at positions 100 mm from the upper end and 100 mm from the lower end of the cylindrical core outer peripheral surface, respectively, and heated under the same conditions as in Example 1. When the temperature difference between the upper end and the lower end was measured, the temperature was 40 ° C after about 30 minutes (in the middle of the temperature rise) immediately after the cylindrical core was put in the heating furnace. It was 4 ° C. in a steady state in which the temperature change at the lower end disappeared.
On the other hand, the same evaluation was carried out using a heating table (heating table A2) provided with a ring-shaped member having a diameter of 300 mm, a height of 40 mm, and a thickness of 5 mm at the tip so that the convex part of the heating table A1 is centered. However, it was found that the temperature difference in the initial state was 25 ° C., the temperature difference in the steady state was 2 ° C., and the temperature variation in the axial direction of the cylindrical core was smaller than that of the heating table A1. This is because the ring-shaped member is substantially in line contact with the jig attached to the circumferential surface of the cylindrical core body, and the contact area between the heating table, the cylindrical core body and the jig is larger. This is thought to be due to the small size.

-Effect of preheat treatment of drying table-
<When preheating temperature is 110 ° C>
In Example 1, the drying table was previously placed in a drying furnace for 30 minutes and heated to 150 ° C., and the cylindrical core body was fixed to the heated drying table, and then placed in the drying furnace. In addition, it was about 110 degreeC when the temperature (preheating temperature) of the drying stand just before putting in a drying furnace was measured.
After drying for 30 minutes in the drying furnace, the cylindrical core was taken out and the amount of the solvent remaining in the film was measured. As a result, the proportion of the solvent in the film was reduced to about 45% by weight. .
The amount of residual solvent in the film was measured by heating from room temperature to 500 ° C. when the temperature was raised at 10 ° C./minute (a thermogravimetric measuring device TGA-50, manufactured by Shimadzu Corporation). Performed.

<Without pre-heat treatment>
In Example 1, except that the pre-heat treatment of the drying table was not performed, the drying process was performed in the same manner as in Example 1. As a result, the residual solvent amount of the film was about 55% by weight, and immediately after removal from the drying furnace. Solvent vapor was still generated from the film, resulting in insufficient drying. In addition, it was found that it took 38 minutes to dry the residual solvent amount to about 45% by weight as in the case where the preheating temperature was set to 110 ° C., and the drying time was long.

<When preheating temperature is 45 ° C>
In Example 1, the drying treatment was performed in the same manner as in Example 1 except that the preheating temperature of the drying table was 45 ° C. The residual solvent amount of the film was about 51% by weight, and immediately after removal from the drying furnace. However, solvent vapor was still generated from the film, and drying was insufficient. Further, it was found that it takes 34 minutes to dry the residual solvent amount to about 45% by weight, as in the case where the preheating temperature is set to 110 ° C.

-Solvent recovery efficiency-
The drying furnace and heating furnace used in Example 1 were connected to an exhaust duct as shown in FIG. 11 so that the solvent volatilized from the coating film or film could be recovered by a heat exchanger or a wet packed tower. .
In addition, since the residual solvent amount contained in the coating film after drying was about 45% by weight as described above, the solvent was volatilized at a rate of 34 g / min in the drying furnace. I understand.

The amount of exhaust gas (gas containing solvent) exhausted from the drying furnace during the drying process was 5 m ³ / min, and this was passed through a heat exchanger. The temperature of the exhaust gas immediately before entering the heat exchanger was 90 ° C.
The heat exchanger used was a multi-tube heat exchanger (total area of the heat transfer wall: 10 m ³ ), and a well water of about 18 ° C. was allowed to flow. It was confirmed that the temperature of the heat transfer wall at this time was around 20 ° C. When the condensed solvent was collected from the bottom of the heat exchanger and the collected amount was measured, it was confirmed that it was collected at a rate of 28 g / min. It was confirmed that 82% of the solvent could be recovered with this heat exchanger.

The amount of exhaust gas (gas containing solvent) exhausted from the heating furnace during the heat treatment was 6 m ³ / min, and this was passed through a heat exchanger. The temperature of the exhaust gas immediately before entering the heat exchanger was 150 ° C. The heat exchanger is the same as that used in the recovery of the solvent generated from the drying furnace.
When the amount of solvent recovered was measured, it was confirmed that 260 g of solvent could be recovered by one heat treatment. Since the residual solvent amount before heating was 320 g, it was confirmed that 81% of the solvent could be recovered with this heat exchanger.

Subsequently, among the exhaust gases discharged from the drying furnace and the heating furnace, the exhaust gas that could not be processed by the heat exchanger (11 m ³ / min exhaust gas exhausted from the drying furnace and the heating furnace) was wet packed tower Supplied to.
As this wet packed tower, TRS-B20 manufactured by Seiko Koki Co., Ltd. was used. The maximum processing capacity is 20 m ³ / min. In the treatment of the exhaust gas, 300 L of water was put in a water tank, and water was supplied from the top of the tower at a rate of 50 L / min.

Subsequently, the concentration of the solvent gas contained in the air before and after the wet packed tower was measured. The solvent gas concentration at the exhaust gas inlet of the wet packed tower was 170 ppm, and the solvent gas concentration at the exhaust gas outlet was 12 ppm. It was confirmed that 93% of the solvent could be recovered in this wet packed tower.
From the above, 98 to 99% of the solvent contained in the exhaust gas is recovered by treating the exhaust gas containing the solvent exhausted from the drying furnace and the heating furnace in combination with the heat exchanger and the wet packed tower. I knew it was possible.

It is a schematic diagram which shows an example of the heating furnace used for the endless belt manufacturing method of this invention. It is a schematic cross section shown about an example of the fixing method which fixes a cylindrical core on a heating stand. It is a schematic cross section shown about the other example of the fixing method which fixes a cylindrical core on a heating stand. It is a perspective view of the heating stand shown in FIG. It is a schematic diagram which shows about the example which suspends a cylindrical core from the upper part of a heating furnace. It is a schematic diagram which shows an example of a drying stand. It is a schematic diagram shown about an example of the method of rotating a cylindrical core. It is a schematic diagram shown about an example of the drying furnace used for the endless belt manufacturing method of this invention. It is a schematic diagram which shows the other example of a drying stand. It is a schematic diagram which shows the other example of a drying stand. It is a schematic diagram which shows an example of the equipment which collect | recovers the gas containing the solvent discharged | emitted from the heating furnace and drying furnace used for the endless belt manufacturing method of this invention. It is a schematic diagram which shows an example of the wet packed tower used for the endless belt manufacturing method of this invention. It is a schematic sectional drawing for demonstrating the coating method. In the conventional endless belt manufacturing method, it is a schematic cross section shown about the fixing method which fixes a cylindrical core on a heating stand.

Explanation of symbols

2 solution 4 coating film 5 annular body 6 annular hole 7 annular coating tank 8 sealing material 10, 11 cylindrical core body 20 cylindrical core body handling jig 22 fixing base 24 shaft rod 30 heating base 32 recess 34 heating base 36 convex part 38 heating stand 40 auxiliary support part (second convex part)
40A Ring-shaped member 40B Pin-shaped member 50 Hook 52 Eyenut 100 Heating furnace 102 Housing 104 Inner chamber 106 Heat source 108 Heat-resistant filter 110 Cylindrical core body 112 with a coating formed on the outer peripheral surface 112 Heating table 200 Drying table 202 Base 204, 204A 204B Fixing member 206 Vent hole 210, 210A, 210B, 210C Tubular core 212 Axle rod 220, 222, 224, 226, 228 Gear 230, 232, 234 Chain 236 Support roll 238 Drive roll 240 Drying furnace 242 Rail 244, 246 Door 248 Housing 300, 302 Heat exchanger 304 Exhaust duct 306 Exhaust fan 308 Wet packed tower 310 Tower 312 Filled 314 Water tank 316 Pump 318 Water supply piping 320 Gas inlet 322 Gas outlet

Claims (7)

A drying step of forming a film by drying a coating film formed on the outer peripheral surface of the cylindrical core body by applying a film-forming resin solution containing a solvent;
In the endless belt manufacturing method for manufacturing an endless belt, at least through a heating step of heating the film by blowing hot air having a temperature of 250 ° C. or more to the film formed on the outer peripheral surface of the cylindrical core body,
The number of particles or particle diameter 0.5μm present per unit volume of the hot air blown to the coating state, and are 35300 pieces / m ³ or less, a gas hot air blown to the film is heated above 250 ° C. endless belt manufacturing method comprising der Rukoto those obtained by filtration through a heat filter. The heating step supplies hot air blown to the film in the heating furnace in a state where the cylindrical core body having the film formed on the outer peripheral surface is disposed in a heating furnace, and heats the film. It is performed while exhausting the gas after finishing out of the heating furnace,
The endless belt manufacturing method according to claim 1, wherein at least a part of the gas after the heating of the coating is circulated in the heating furnace and reused. In the heating step, the cylindrical core handling jig is fixed to the cylindrical core body peripheral surface so that the axial direction of the cylindrical core body in which the film is formed on the outer peripheral surface coincides with the vertical direction. After being fixed to the heating table via, the cylindrical core fixed to the heating table is placed in a heating furnace,
When the cylindrical core body handling jig is fixed to the inner peripheral side by contacting the inner peripheral surface of the cylindrical core body, and when the fixed base is fixed to the inner peripheral side, A shaft rod attached to the fixed base so as to substantially coincide with an axial line of a cylindrical core body, The endless belt manufacturing method according to claim 1 or 2,
An endless belt manufacturing method, wherein the heating base includes a base and a convex portion provided on a surface opposite to the bottom surface of the base and capable of fitting with the shaft rod. In the heating step, the cylindrical core body fixed to the heating table is fixed to the heating table so that the axial direction of the cylindrical core body with the coating formed on the outer peripheral surface coincides with the vertical direction. Is an endless belt manufacturing method according to claim 1 or 2, wherein the endless belt is manufactured by being disposed in a heating furnace,
The heating table includes a base and a convex portion that is provided on a surface opposite to the bottom surface of the base and can be fitted to the inner peripheral surface side and / or the outer peripheral surface side of the cylindrical core body. An endless belt manufacturing method. In the drying step, after fixing the cylindrical core body, on which the coating film is formed on the outer peripheral surface, to a drying table, the furnace is previously placed in a drying furnace heated to 50 ° C. or more and heated. It is an endless belt manufacturing method as described in any one of Claims 1-4 performed by these,
Before the cylindrical core body with the coating film formed on the outer peripheral surface is fixed to the drying table, the drying table is pre-heated to a temperature within the range of 50 ° C. to the furnace temperature of the drying furnace. An endless belt manufacturing method comprising: The solvent includes a water-soluble solvent having a boiling point exceeding 100 ° C .;
The drying step is performed by placing the cylindrical core body having the coating film formed on the outer peripheral surface thereof in a drying furnace in which the furnace temperature is maintained at 50 ° C. or higher,
The heating step is performed by disposing the cylindrical core body having the coating formed on the outer peripheral surface thereof in a heating furnace in which the furnace temperature is maintained at 250 ° C. or higher,
The gas containing the solvent volatilized from the coating film in the drying furnace is discharged outside the drying furnace, and the gas containing the solvent volatilized from the film in the heating furnace is discharged outside the heating furnace. An endless belt manufacturing method according to any one of claims 1 to 5 ,
By passing the gas containing the solvent discharged from the heating furnace and / or the drying furnace through a heat exchanger having a heat transfer wall temperature of 40 ° C. or less, the solvent is liquefied from the gas containing the solvent. And collecting the endless belt. The gas containing the solvent discharged from the heating furnace and / or the drying furnace is passed through the heat exchanger and then passed through a wet packed tower using water to dissolve the solvent in the water. It collect | recovers, The endless belt manufacturing method of Claim 6 characterized by the above-mentioned.

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