JP3976463B2 - Endless belt manufacturing method, damming member correction method, and damming member correction jig - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an endless belt manufacturing technique, and more particularly to a method for manufacturing an endless sheet-shaped resin belt and a method for correcting a damming member used in the manufacturing method. The present invention can be widely and effectively applied to fixing belts and intermediate transfer belts in electrophotographic copying machines and the like.
[0002]
[Prior art]
The endless belt is conventionally manufactured by a centrifugal molding method. This centrifugal molding method is performed as follows, for example. First, a raw material liquid (for example, a resin solvent solution) is injected and applied into a cylindrical mold that rotates at a low speed. Next, the mold is rotated at a high speed, and the resin liquid (coating liquid) is cast on the inner peripheral surface (molded surface) of the mold by a centrifugal force to expand the film thickness to a uniform thickness. Thereafter, the coating solution is dried by heating and solidified to form an endless sheet-like belt, and finally, the endless belt is peeled and removed from the mold.
[0003]
In this endless belt manufacturing method,
(1) The coating thickness of the raw material liquid can be arbitrarily adjusted according to the amount of injected liquid.
(2) The required amount of raw material liquid may be applied, and the usage efficiency of the raw material liquid is good.
(3) The inside of the mold is a sealed space, and when removing the solvent from the coating solution, a solvent trap can be provided in the exhaust path to efficiently recover the solvent discharged to the outside. There are excellent benefits.
[0004]
However, in this centrifugal molding method, if rotation of the mold is continued in order to make the film thickness of the resin liquid (coating liquid) uniform, this is cast to the end of the mold, and the belt Both ends in the width direction are thinner than the central part, and irregular resin dripping occurs. Therefore, not only is it difficult to peel and take off after drying and solidification, but also a holder such as a chuck that holds the mold. There was a problem of getting dirty.
[0005]
In order to solve this problem, it is necessary to stop the casting of the resin liquid in the mold at an appropriate location. As a means for that purpose, a tape made of a fluororesin has been conventionally attached to the inner peripheral surface of the end portion of the mold with an adhesive, and this has been used as a blocking member for the resin liquid.
[0006]
However, such a tape-shaped damming member takes time and effort to mount, and the adhesive dissolves in the solvent in the resin liquid, so that it does not serve as a damming function, or the holder is soiled. Furthermore, when the inner diameter of the mold is small, there is also a problem that manual tape sticking becomes impossible.
[0007]
In view of this, the present inventors have disclosed, in the specification and drawings of Japanese Patent Application No. 11-20880, as a technique for solving the above-mentioned conventional problems, at least two ring-shaped damming members are provided on the inner peripheral surface of the mold. A method of manufacturing an endless resin belt by a centrifugal molding method was proposed in which a molding cavity is formed by two damming members and an inner peripheral surface of a molding die provided apart from each other.
[0008]
[Problems to be solved by the invention]
However, subsequent studies by the present inventors have revealed that there are the following problems. That is, in the manufacturing method according to the above patent application, if there is even a slight gap between the inner peripheral surface of the mold and the outer peripheral surface of the damming member, the resin liquid penetrates into the gap, and the resin liquid is solidified by solvent evaporation. When drying and solidification is performed afterwards, the molding film floats up and shrinks from the inner peripheral surface of the mold when it is heated and solidified, so the damming member must be in close contact with the inner peripheral surface of the mold Don't be.
[0009]
Moreover, when a material made of a fluororesin (for example, PTFE), which is a heat-resistant plastic, is used as the damming member, it shrinks when it is cooled after heating, and the inner and outer diameters become smaller than before heating, so that it can be reused as it is. In this case, a trouble occurred that a gap was generated between the inner peripheral surface of the mold and the outer peripheral surface of the damming member, so that the role of damming was not achieved. This is presumably because the stress remaining when the damming member was produced by molding was not sufficiently eliminated, so that it gradually contracted in the heating / cooling heat cycle.
[0010]
The present invention has been made in view of the above-mentioned problems, and its purpose is to simplify a method for manufacturing an endless belt that corrects and reuses a damming member after use, and a method for correcting a damming member after use. It is to be provided at a low cost with a simple configuration.
[0011]
[Means for Solving the Problems]
The endless belt manufacturing method according to claim 1, wherein a plurality of plastic or rubber ring-shaped damming members are attached in close contact with each other on a cylindrical inner peripheral surface of a mold, and the weirs facing each other. A centrifugal mold having a molding cavity formed by a stopper member and the inner peripheral surface of the cylinder is prepared, the mold is rotated around a horizontal central axis, and in this state, a raw material liquid containing a solvent is injected and applied to the molding cavity. , A method of forming an endless belt by evaporating the solvent by heating and drying and solidifying the coating liquid while continuing to rotate the mold, and heating the weir member whose diameter after use is reduced It is characterized by being expanded in diameter and reused for centrifugal molding.
[0012]
The endless belt manufacturing method according to claim 2, wherein a plurality of plastic or rubber ring-shaped damming members are mounted in close contact with each other on a cylindrical inner peripheral surface of a mold, and the weirs facing each other. A centrifugal mold having a molding cavity formed by a stopper member and the inner peripheral surface of the cylinder is prepared, the mold is rotated around a horizontal central axis, and in this state, a raw material liquid containing a solvent is injected and applied to the molding cavity. A method of forming an endless belt by evaporating the solvent by heating while continuing to rotate the molding die to dry the coating liquid by touch and then heating and drying and solidifying the dry touch film Then, the weir member whose diameter after use is reduced is expanded by heating and reused for centrifugal molding.
[0013]
A method for producing an endless belt according to claim 3 is the method according to claim 1 or 2, wherein the endless belt is inserted into the molding die by pressing the damming member and sliding it on the cylindrical inner peripheral surface of the molding die. It is characterized by forming.
[0014]
A method for producing an endless belt according to claim 4 is the method according to claim 1 or 2, wherein a ring-shaped detent member for preventing the molded endless belt from shifting when traveling is formed in the molding cavity, and By inserting the damming member in contact with the side surface of the damming member, a detenting member is integrally formed at both ends in the width direction of the endless belt.
[0015]
According to a fifth aspect of the present invention, there is provided a method for manufacturing an endless belt according to the fourth aspect, wherein the stopper member is inserted into the molding die by pressing the stopper member and sliding on the cylindrical inner peripheral surface of the molding die. It is made to contact the side surface of a dam member.
[0016]
According to a sixth aspect of the present invention, there is provided a method for producing an endless belt according to the second aspect of the present invention, wherein a weir member having a thermal expansion coefficient larger than that of the mold is used as the weir member. The outer peripheral surface of the member is in pressure contact with the inner peripheral surface of the cylinder of the mold, and the outer diameter of the blocking member is reduced by the heat shrinkage after the drying and solidification process of the dry touch film obtained in the touch drying process. It is characterized by being made smaller than the diameter of the inner peripheral surface.
[0017]
The manufacturing method of the endless belt according to claim 7 is the endless belt according to claim 6, wherein the outer diameter of the blocking member is an endless shape in the mold due to thermal contraction in the drying / solidifying process of the dry touch film. Use a thermal expansion coefficient that is smaller than the inner diameter of the belt and that has a coefficient of thermal expansion greater than that of the mold. Place the mold after the touch drying process vertically in a heating and drying oven to dry and solidify the dry touch film. Thus, an endless belt is obtained, and the damming member is naturally dropped from the mold and collected.
[0018]
An endless belt manufacturing method according to an eighth aspect is characterized in that, in any one of the first to seventh aspects, the damming member is made of a fluororesin, preferably PTFE (polytetrafluoroethylene).
[0019]
In order to reuse the damming member according to claim 9 in the manufacturing method of the endless belt according to claim 1 or 2, the damming member having a reduced diameter after use is expanded by heating. A first cylindrical portion made of metal, glass or ceramics and having an outer diameter that is large enough to insert and lock the inner peripheral surface of the damming member, and a diameter that increases continuously with the first cylindrical portion. A correction jig comprising a hollow conical taper portion and a second cylindrical portion connected to the taper portion is prepared, and a correction jig in which a weir member is inserted and locked to the outer peripheral surface of the first cylinder portion is The damming member is heated in a state in which the cylindrical portion is in the lower part so as to be the lower portion, and the expanded damming member is dropped by its own weight onto the lower end portion of the second cylindrical portion through the tapered portion. The damming member is allowed to cool to room temperature with By that equal to the outer diameter of the second cylindrical portion, the outer diameter of the dam member Return to the outer diameter of the blocking member before use It is characterized by that.
[0020]
The basic principle for reusing the damming member according to the present invention is that the damming member made of plastic or rubber utilizes thermal characteristics that expand / contract by heating / cooling.
[0021]
That is,
(1) By heating the contracted damming member to thermally expand it and returning it to the dimension before contraction, by maintaining this dimension, it is possible to adhere to the inner peripheral surface of the mold to be used next time.
(2) For this purpose, the heat-expanded damming member is inserted into an appropriate mold, and the inner peripheral surface of the damming member may be brought into contact with the outer peripheral surface of the mold so as not to shrink.
(3) Also, if there is a possibility of further shrinkage due to internal stress relaxation even when the temperature of the damming member reaches room temperature, the reverse process (expansion) from the ultimate temperature can be achieved by once cooling to below the operating temperature. Therefore, it can be maintained at a diameter larger than the initial diameter (initial diameter: inner and outer diameters of a new weir member).
(4) Since the weir member corrected by the above processing can be attached in a state of being in close contact with the molding die, the original function and effect of the weir member can be obtained.
(5) If the damming member is not heated to a thermal decomposition temperature or higher, the damming member can be repeatedly straightened many times.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
FIG. 1 is a schematic cross-sectional view showing a mold and a raw material liquid (for example, resin liquid: resin solvent solution) cast in the molding cavity. Two plastic or rubber ring-shaped weir members 2 and 2 are inserted into the centrifugal mold 1 (hereinafter sometimes referred to as a mold) at a predetermined interval, and the outer periphery of these weir members The molding cavity 1 a is formed by bringing the surface into close contact with the cylindrical inner peripheral surface of the mold 1. That is, the molding cavity 1a is formed by the weir members 2 and 2 facing each other and the cylindrical inner peripheral surface.
[0023]
When molding the endless belt, the mold 1 is set on a centrifugal molding machine (not shown) and rotated around the horizontal central axis. In this state, the raw material liquid 3a is injected into the molding cavity 1a, While casting, the raw material liquid is heated to evaporate the solvent, thereby forming a dry touch film. The molding die is taken out from the centrifugal molding machine, set in a heating and drying furnace (not shown), and the endless belt is molded by heating and drying and solidifying the touch-dried film.
[0024]
Thereafter, the mold 1 is allowed to cool, and the endless belt is peeled and collected from the mold 1 and the two damming members are removed. These damming members are contracted by cooling after heating, and the inner and outer diameters are reduced compared to before use. Therefore, when this damming member is reused as it is, a gap is formed between the outer peripheral surface of the damming member 2 and the cylindrical inner peripheral surface of the mold 1 as shown in FIG. This causes a problem of leaking outside through this gap. Therefore, in the present invention, the weir member whose diameter after use has been reduced is corrected by heating (expanding diameter: expanding the diameter) and reused for centrifugal molding. This will be described later.
[0025]
In the dam member 2 shown in FIG. 1, it is preferable that the side surface which contacts a raw material liquid becomes a plane orthogonal to the central axis of this dam member. Further, since the side surface of the weir member is in contact with the raw material liquid in the molding process, it is desirable that the solvent in the raw material liquid is not affected. Further, it is desirable that the damming member is in close contact with the molding surface so as not to be peeled off from the molding surface (cylindrical inner peripheral surface of the mold) or to be displaced or dropped during centrifugal molding at high speed. Furthermore, it is important that the material does not soften in the drying / solidification step (usually a temperature range of about 100 ° C. to 200 ° C.).
[0026]
In the present invention, as shown in FIG. 1, since the weir member 2 is mounted in close contact with the molding surface, resin dripping from both ends of the molding die is prevented, and an endless belt having a uniform film thickness is stabilized. Can be molded.
[0027]
As materials for the weir member 2, polytetrafluoroethylene (PTFE), polyhexafluoropropylene (PHFP), polychlorotrifluoroethylene (PCTFE), polyfluorovinylidene (PVdF), polyfluorovinyl (PVF) and polyfluoro A fluororesin such as ethylene propylene (PFEP) is preferred. Among these, PTFE which is excellent in solvent resistance, heat resistance, non-adhesiveness, releasability and the like is particularly preferable.
[0028]
FIG. 3 is a schematic cross-sectional view for explaining the method of correcting the damming member (contraction thereof) by the correction jig and the operation thereof. The metal straightening jig 11 shown in FIG. 3 has a coefficient of thermal expansion that is much smaller than that of the damming member 2 and has an outer diameter that allows the inner peripheral surface of the damming member 2 to be inserted and locked. It consists of a certain first cylindrical portion 11a, a hollow conical tapered portion 11b which is continuous with the first cylindrical portion and has a gradually increasing diameter, and a second cylindrical portion 11c which is continuous with the tapered portion. The outer diameter of the second cylindrical portion 11c is the same as that of the damming member after correction. Return to the outer diameter of the blocking member before use Is set to
[0029]
At the time of correction, as shown in FIG. 3, the correction jig 11 is fixed vertically on the pedestal 12 so that the second cylindrical portion 11c is at the lower portion, and the dam member (before correction) 2 is fixed to the first cylindrical portion 11a. The straightening jig 11 is inserted into a heating furnace (not shown) integrally with the base 12 and the damming member 2 and the straightening jig 11 are heated to appropriate temperatures for a predetermined time. Thereby, the expanded dam member 2 falls to the lower end portion of the second cylindrical portion 11c through the tapered portion 11b due to its own weight. The inner and outer diameters of the weir members that have dropped to the lower end of the second cylindrical portion 11c are almost equal to the initial values. In this state, by allowing the straightening jig and the damming member to cool to room temperature, the inner and outer diameters of the damming member 2 are maintained at the initial values. The dam member 2 after being allowed to cool can be easily extracted from the lower end of the second cylindrical portion 11c by removing the correction jig 11 from the pedestal 12.
[0030]
Embodiment 2
FIG. 4 is a schematic cross-sectional view showing a mold and a raw material liquid (resin liquid) cast in the molding cavity. Four plastic or rubber ring-shaped dam members 2 are inserted into the mold 1 at predetermined intervals, and the outer peripheral surfaces of these dam members are in close contact with the cylindrical inner surface of the mold 1 Thus, three molding cavities 1a are formed.
[0031]
When molding an endless belt, the mold 1 is set on a centrifugal molding machine (not shown) and rotated around a horizontal central axis. In this state, a raw material liquid is injected into each molding cavity, While casting, the raw material liquid is heated to evaporate the solvent, thereby forming a dry touch film. Hereinafter, three endless belts can be obtained by one molding in the same manner as in the first embodiment.
[0032]
Embodiment 3
FIG. 5 is a schematic cross-sectional view showing a molding die and a raw material liquid cast in the molding cavity. In addition to setting the four weiring members 2 in the same manner as in FIG. 4, the forming die 1 has a ring-shaped detent member 4 for preventing the formed endless belt from deviating during travel. Are inserted in contact with the side surface of the damming member 2. According to this mold, three endless belts in which the detent members 4 are integrally formed at both ends in the width direction of the endless belt can be obtained by one molding. As the stopper member 4, for example, a conventionally known stainless steel mesh belt can be used.
[0033]
Embodiment 4
FIG. 6 is a schematic cross-sectional view of the case where the molding die of FIG. 4 is configured by inserting and setting a damming member into a cylindrical mold to form a molding cavity. As shown in FIG. 6, the dam member 2 whose outer diameter is slightly smaller than the cylindrical inner diameter D1 is pressed by the insertion jig 21, and inserted and set at a predetermined position of the cylindrical type while sliding on the inner peripheral surface of the cylinder. . Further, the stopper member 4 can be inserted and set in the same manner as the dam member 2, and the keeper member 4 is brought into contact with the side surface of the dam member 2 as shown in FIG.
[0034]
Embodiment 5
After the endless belt is formed, it is important that the weir member can be easily taken out from the forming die. Therefore, in the present embodiment, as shown in FIG. 7, as the dam member 2, a member in which a hook hole 2a for a drawing tool (not shown) is formed in a portion that does not contact the raw material liquid 3a at the time of molding is molded. A cavity is formed. FIG. 7A is a sectional view of the damming member 2, and FIG. 7B is an enlarged plan view thereof. Thereby, the blocking member 2 can be taken out easily and without touching the thin film belt.
[0035]
Embodiment 6
The molding die 1 according to the present embodiment replaces the hooking hole 2a of the fifth embodiment with the damming member 2 provided with the hooking protrusion 2b as shown in FIG. The operation of taking out the damming member 2 is simplified. FIG. 8A is a sectional view of the damming member 2, and FIG. 8B is an enlarged plan view thereof.
[0036]
Embodiment 7
FIG. 9 shows a method for recovering the weir member by naturally dropping it from the mold after forming the endless belt. FIG. 9A is a cross-sectional view of the mold on which the dry touch film is formed. (B) is a method in which this mold is set in a heating / drying furnace in the vertical direction, the touch-dried film is dried and solidified to obtain an endless belt, and the weir member is naturally dropped from the mold and recovered. It is sectional drawing shown.
[0037]
Also in the present embodiment, the weir member 2 having a thermal expansion coefficient larger than that of the mold 1 is used. That is, in the molding process, the outer peripheral surface comes into pressure contact with the cylindrical inner peripheral surface of the mold 1 due to thermal expansion of the weir member 2, and after the molding process, the outer diameter of the weir member becomes the cylindrical inner peripheral surface of the mold 1 due to thermal contraction. Use one that is smaller than the diameter. Thereby, not only the original action of the damming member can be obtained, but also the member can be easily detached from the mold after the molding step, for example, as follows.
[0038]
In the recovery method of the dam member according to the seventh embodiment, the following is used as the dam member (see FIG. 9).
(1) The outer diameter is equal to or slightly smaller than the inner diameter D1 of the mold 1, and when it is inserted into the mold 1, it is in close contact with the inner peripheral surface of the cylinder.
(2) In the process of drying the injection raw material liquid in the molding cavity with the touch and then drying and solidifying the dry touch film 3b by heating, the outer peripheral surface of the blocking member is thermally expanded in the cylinder of the mold 1 It is in pressure contact with the peripheral surface.
(3) When the weir member is cooled after the drying / solidifying step, the outer diameter D3 of the weir member becomes smaller than the inner diameter D2 of the endless belt 3c in the mold 1 due to thermal contraction.
[0039]
Next, a method for collecting the weir member will be described with reference to the drawings. The mold 1 after the touch-drying is set in a heating and drying furnace (not shown) in the vertical direction. In this case, as shown in FIG. 9B, the mold 1 is fixed on the appropriate mold holder 31 in the vertical direction, and the mold holder 31 is inserted into the heating and drying furnace as it is. Subsequently, after drying and solidifying the dry touch film 3b [FIG. 9A] to form an endless belt 3c, the mold is allowed to cool to room temperature in a heating and drying furnace.
[0040]
In the molding process, as shown in FIG. 9A, the outer peripheral surface of the blocking member 2 is in pressure contact with the cylindrical inner peripheral surface of the mold 1, but after the molding process is completed, the blocking member 2 is thermally contracted. Since the outer diameter D3 is smaller than the inner diameter D2 of the endless belt 3c, the damming member 2 naturally falls and is collected by the mold holder 31 as shown in FIG.
[0041]
【Example】
Next, examples of the present invention will be described.
Example 1
As shown in FIG. 1, a mold made of aluminum (coefficient of thermal expansion 2.5 × 10 ^-Five / ° C), a new PTFE ring weir member (thermal expansion coefficient 8 × 10) ^-Five ~ 12x10 ^-Five / ° C.) were inserted and set, and then the mold was set in the centrifugal molding machine in the horizontal direction. While the mold was rotated at a low speed around the horizontal central axis, a polyimide precursor varnish was gradually injected as a raw material solution to form a coating film. Next, by rotating the mold at a high speed, the film thickness of the coating film is made uniform, and further, the coating liquid is dried and solidified by heating at 70 ° C. for about 30 minutes while rotating the mold at a high speed. A belt was obtained. The molding die was taken out from the centrifugal molding machine, and the damming member was removed from the molding die. As a result, the damming member could be easily removed. Further, the raw material liquid did not leak from the mold, and the members around the mold were not soiled.
[0042]
When the removed damming member was reinserted and set in the mold, the damming member was contracted compared to that before use in Example 1, so that the gap between the damming member and the cylindrical inner peripheral surface of the mold was reduced. A gap has occurred. Therefore, the shrunk damming member was inserted and locked into the first cylindrical portion 11a of the correction jig 11 made of aluminum shown in FIG. 3, and this was placed in a heating furnace and heated at 100 ° C. or higher.
[0043]
When observing, the damming member 2 dropped the first cylindrical portion 11a and then the tapered portion 11b as the temperature rose, and dropped to the lower end of the second cylindrical portion 11c when the temperature was sufficiently raised. The correction jig 11 was taken out of the heating furnace together with the base 12 and allowed to cool to room temperature. As a result, the weir member 2 gradually contracted, and the dimensions and form of the weir member 2 were stabilized when the outer diameter became almost equal to the outer diameter of the second cylindrical portion 11c.
[0044]
Thereafter, when the weir member 2 was removed from the correction jig 11 and inserted into the mold, it was able to be set in a state of being in close contact with the inner peripheral surface of the cylinder as with a new weir member. As a result of molding the endless belt again using this mold, there was no leakage of the raw material liquid from the mold and a good quality endless belt was obtained. The reason why the damming member after correction can be set in such a state that the damming member is in close contact with the cylindrical inner peripheral surface of the molding die is that the outer diameter of the second cylindrical portion 11c is set to an appropriate value. .
[0045]
Comparative Example 1
In Example 1, instead of taking out the correction jig 11 from the heating furnace together with the pedestal 12 and allowing it to cool to room temperature as it is, the damming member in a state where the correction jig 11 taken out of the heating furnace has not yet been sufficiently cooled. Was removed and allowed to cool to room temperature overnight. The next day, when this blocking member was to be attached to the mold, a gap was formed between the inner peripheral surface of the mold and the cylinder. As a result of injection, application, heat drying and solidification of the raw material liquid using this mold as it is, there is evidence that the raw material liquid has flowed between the outer peripheral surface of the blocking member and the inner peripheral surface of the mold. It was.
[0046]
Example 2
In Example 1, instead of taking out the correction jig 11 together with the pedestal 12 from the heating furnace and allowing it to cool to room temperature as it was, the correction jig 11 was taken out of the heating furnace together with the pedestal 12 and stored in the refrigerator. After being sufficiently cooled (for 3 hours or more), the weir member was removed from the correction jig. After leaving it for one day or more as it was, it was set in a mold, and the weiring member was in close contact with the inner circumferential surface of the cylinder of the mold, and a normal molding operation could be performed.
[0047]
Example 3
As in Example 1, the setting of the blocking member to the mold and the correction work were repeated 100 times or more. As a result, proper correction work of the damming member could be performed with good reproducibility, and no deterioration was found in the inner and outer diameter recovery of the damming member and the damming effect at the time of applying the raw material liquid.
[0048]
Comparative Example 2
When the damming member used in Example 1 was reused without correction, the raw material liquid leaked from the end of the mold, so that the rotating holder of the centrifugal molding machine was soiled, and a great deal of time was required for cleaning. It cost. Further, in the undried coating liquid portion, the coating film floated and contracted from the cylindrical inner peripheral surface of the mold, so that a trouble that a good endless belt could not be obtained frequently occurred.
[0049]
Example 4
As shown in FIG. 4, after inserting and setting four PTFE weir members corrected in the same manner as in the first embodiment at equal intervals using the insertion jig 21 shown in FIG. The mold was set in a centrifugal molding machine, and the raw material liquid was injected while rotating the mold. Further, the coating solution was heated by rotating the mold to dry the coating solution. The mold was removed from the centrifugal molding machine, inserted into a heating and drying furnace in the vertical direction, and heated at 100 ° C. for 30 minutes (see FIG. 9). Then, when the heating and drying furnace was cooled and returned to room temperature, the damming member could be dropped and collected at the bottom of the furnace while the obtained endless belt remained attached to the mold. For this reason, there was no need to manually remove the weir member from the mold.
[0050]
【The invention's effect】
As is apparent from the above description, the present invention provides the following effects.
(1) A method for producing an endless belt according to claims 1 and 2
When manufacturing an endless belt using a centrifugal mold, a weir member with a predetermined configuration is closely inserted into the mold to form a molding cavity, and the raw material liquid is injected into this molding cavity. Thus, it is possible to accurately prevent the resin dripping, and to manufacture a high-quality belt stably. Further, if a large number of weir members are set in a long mold, a large number of endless belts can be obtained by a single molding operation.
[0051]
In the present invention, in particular, a damming member made of an elastic or flexible thermoplastic organic polymer resin is used, and the damped member after shrinkage is molded before use by so-called heat setting. Since the size and shape are restored / stabilized and reused, the damming member can be used effectively.
[0052]
(2) The manufacturing method of the endless belt according to claim 3
Since the damming member is pressed and slid on the cylindrical inner peripheral surface of the mold, it is inserted into the mold, so that the insertion and setting can be performed easily.
[0053]
(3) A method for producing an endless belt according to claims 4 and 5
It is possible to simply insert and set the stopper member into the mold. In addition, since an endless belt in which the stopper member is integrally formed is obtained, the belt with the stopper member can be manufactured by a simple process.
[0054]
(4) A method for producing an endless belt according to claims 6 and 7
The removal / recovery operation of the damming member from the mold, which is performed after the endless belt molding, can be easily and efficiently performed. In particular, according to the manufacturing method of claim 7, after the endless belt is obtained, there is a remarkable effect that the damming member can be recovered from the mold by natural fall.
[0055]
(5) The manufacturing method of the endless belt according to claim 8
Uses a damming member made of a fluororesin that has excellent heat resistance, solvent resistance, and peelability, making it easy to handle, allowing it to fully function as a damming member, and a molded endless belt Can be easily separated from the damming member.
[0056]
(6) The correction method of the damming member according to claim 9
A damming member is inserted and locked to the outer peripheral surface of a straight jig having a predetermined configuration, and the damming member is heated to an appropriate temperature and thermally expanded while the straightening jig is kept in a vertical direction, and then dammed in the inserted state. Since the member is allowed to cool to room temperature, the damming member can be corrected by a simple operation.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a molding die according to Embodiment 1 and a resin liquid cast in a molding cavity.
FIG. 2 is a schematic cross-sectional view illustrating a problem when a damming member after use is reused without being corrected.
FIGS. 3A and 3B are schematic cross-sectional views for explaining a method of correcting a damming member using a correction jig and its operation according to the first embodiment. FIGS.
4 is a schematic cross-sectional view showing a molding die according to Embodiment 2 and a resin liquid cast in the molding cavity. FIG.
5 is a schematic cross-sectional view showing a molding die according to Embodiment 3 and a resin liquid cast in the molding cavity. FIG.
6 relates to the fourth embodiment, and is a schematic cross-sectional view of the centrifugal mold shown in FIG. 4 when a dam member is inserted into the mold. FIG.
7A and 7B relate to the fifth embodiment, in which FIG. 7A is a cross-sectional view of a damming member in which a hook hole is formed, and FIG. 7B is an enlarged plan view thereof.
8A and 8B relate to the sixth embodiment, in which FIG. 8A is a cross-sectional view of a damming member provided with a hooking projection, and FIG. 8B is an enlarged plan view thereof.
FIG. 9 relates to Embodiment 7, wherein (a) is a schematic cross-sectional view of a molding die on which a dry touch film is formed, (b) is a vertical setting of this molding die in a heating and drying furnace, FIG. 3 is a schematic cross-sectional view showing a method for drying and solidifying a touch-sensitive dry film to obtain an endless belt, and a method for recovering a weir member by naturally dropping it from a mold.
[Explanation of symbols]
1 Centrifugal mold (mold)
1a Molding cavity
2 Damping member
2a hook hole
2b hook projection
3a Raw material liquid (resin liquid)
3b Dry touch film
3c endless belt
4 Locking member
11 Straightening jig
11a 1st cylindrical part
11b Taper part
11c 2nd cylindrical part
12 pedestal
21 Insertion jig
31 type holder
D1 Inner diameter of mold (cylindrical)
D2 Inside diameter of endless belt
D3 Outside diameter of weir member (after heat shrink)

Claims (9)

 A plurality of plastic or rubber ring-shaped damming members are attached in close contact with the inner peripheral surface of the molding die at predetermined intervals, and a molding cavity is formed by the damming members facing each other and the inner peripheral surface of the cylinder A centrifugal mold is prepared, the mold is rotated around a horizontal central axis, and in this state, a raw material liquid containing a solvent is injected and applied to the molding cavity, and the solvent is removed by heating while continuing to rotate the mold. A method of forming an endless belt by evaporating and drying and solidifying the coating solution, wherein a weir member whose diameter has been reduced after use is expanded by heating and reused for centrifugal molding A method for producing an endless belt.  A plurality of plastic or rubber ring-shaped damming members are attached in close contact with the inner peripheral surface of the molding die at predetermined intervals, and a molding cavity is formed by the damming members facing each other and the inner peripheral surface of the cylinder A centrifugal mold is prepared, the mold is rotated around a horizontal central axis, and in this state, a raw material liquid containing a solvent is injected and applied to the molding cavity, and the solvent is removed by heating while continuing to rotate the mold. A method of forming an endless belt by evaporating and drying the coating liquid to the touch and then drying and solidifying the touch-dried film, wherein the weir member has a reduced diameter after use. A method for producing an endless belt, wherein the diameter is expanded by heating and reused in centrifugal molding.  The endless belt according to claim 1 or 2, wherein the dam member is pressed and slid on the cylindrical inner peripheral surface of the mold to be inserted into the mold to form a molding cavity. Method.  By inserting a ring-shaped detent member for preventing the molded endless belt from shifting during running into the molding cavity and in contact with the side surface of the weir member, the width of the endless belt The method for producing an endless belt according to claim 1 or 2, wherein a detent member is integrally formed at both ends in the direction.  5. The stopper according to claim 4, wherein the stopper member is pressed and slid on the cylindrical inner peripheral surface of the molding die to be inserted into the molding die, and the stopper member is brought into contact with a side surface of the damming member. A method for producing an endless belt.  By using a weir member with a coefficient of thermal expansion greater than that of the mold, the outer surface of the weir member is pressed against the inner surface of the cylinder of the mold by thermal expansion in the touch drying process, and the touch is dried. The outer diameter of the damming member is made smaller than the diameter of the cylindrical inner peripheral surface of the mold by heat shrinkage after the drying and solidification step of the dry touch film obtained in the step. A process for producing an endless belt as described in 1.  As a weir member, the thermal expansion coefficient is smaller than that of the mold so that the outer diameter of the weir member is smaller than the inner diameter of the endless belt in the mold due to thermal contraction in the drying / solidification process of the dry touch film. Use a large one, put the mold after the touch drying process vertically in the heating drying oven, dry and solidify the touch drying film to obtain an endless belt, and let the weir member fall naturally from the mold And collecting the endless belt according to claim 6.  The method for producing an endless belt according to any one of claims 1 to 7, wherein the damming member is made of a fluororesin.  In order to reuse the endless belt manufacturing method according to claim 1 or 2, it is a method of expanding a weir member whose diameter after use is reduced by heating, and is made of metal, glass or ceramics, A first cylindrical portion having an outer diameter that is large enough to insert and lock the inner peripheral surface of the damming member, a hollow conical tapered portion that is continuous with the first cylindrical portion, and that gradually increases in diameter, and is continuous with the tapered portion A straightening jig comprising a second cylindrical portion was prepared, and the straightening jig in which a damming member was inserted and locked on the outer peripheral surface of the first cylindrical portion was aligned along the vertical direction so that the second cylindrical portion was at the bottom. The dam member is heated in this state, and the expanded dam member is dropped to the lower end of the second cylindrical portion through the taper portion by its own weight. By making the inner diameter of the weir member equal to the outer diameter of the second cylindrical portion Straightening method of dam members and returning to the outer diameter of the dam member before using the outer diameter of the dam member.

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