JP2000343620A - Production condition setting method in production of endless belt, and method and apparatus for producing endless belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a coating soln. to a desired drying state by preliminarily grasping the wt. ratio of the solid of the coating soln. per a unit area in the coating region in a mold to set a heating state bringing the coating soln. to a desired drying state. SOLUTION: If the ratio of the solid wt. of a polyamide acid soln. per a unit area in the coating region in a mold is cleared, the amt. to be evaporated of a solvent is estimated until a coating soln. becomes a contact drying state, that is, the wt. ratio of the residual solvent in the coating soln. becomes 0.25 γwith respect to the wt. ratio γ of the solid in the coating solution. Therefore, if the relation of the evaporation amt. of a solvent to the heating condition of the polyamide acid soln. is preliminarily calculated by experimentation, a heating condition drying the polyamide acid soln. to a contact drying state can be set. By this constitution, the lowering of production efficiency by excessive drying or release demolding inferiority after molding is eliminated and the liquid dripping or thickness irregularity after coating caused by drying insufficiency can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting an endless belt for producing an endless belt by applying a coating solution in a cylindrical mold, heating and drying and solidifying the coating solution to produce an endless belt. It is about the method. In addition, the present invention relates to a method for producing an endless belt for producing a polyimide endless belt by applying a polyimide precursor solution in a cylindrical mold and heating and drying and solidifying the solution. The present invention also includes a cylindrical mold to which the coating liquid is applied and used, and heating means for heating the coating liquid in a state where the coating liquid is applied to the inner surface of the mold, and The present invention relates to an endless belt manufacturing apparatus that manufactures an endless belt by drying and solidifying a liquid.

[0002]

2. Description of the Related Art Conventionally, seamless endless belts have been used in various belt devices. For example, in an image forming apparatus such as an electrophotographic copying machine, a facsimile, or a printer, a transfer belt as a carrier for a toner image or a transfer material is employed.

As a method for manufacturing the above-mentioned transfer belt, a centrifugal molding method has been conventionally used. Hereinafter, a method for manufacturing a polyimide transfer belt by a centrifugal molding method will be described.
Polyimide is a material that satisfies flame retardancy, strength, and electrical stability required when used as a transfer belt of the image forming apparatus, and is a material that is particularly expected in strength and triboelectric charging. .

[0004] A polyimide precursor solution as a coating solution is applied to the inner surface of a cylindrical centrifugal mold by spraying or poured from a nozzle, and the mold is rotated at high speed. Due to this centrifugal force, the solution is cast to form an endless film of the polyimide precursor solution on the inner peripheral surface of the mold. Subsequently, while the mold is being rotated, the solvent in the polyimide precursor solution is evaporated by means such as heating, and the endless film is dried and solidified. Further, the endless film is heated to close the imide ring, cured,
Next, the endless film is separated from the mold through cooling, whereby a polyimide transfer belt can be obtained. The curing treatment by heating may be performed by removing the endless film of the polyimide precursor from the mold for centrifugal molding.

The conditions for forming an endless film in such a centrifugal molding method are as follows: the inner diameter of the mold is D, and the rotational angular velocity is ω.
It is known that if (sec ⁻¹ ), it is necessary to satisfy the relationship of ω = 42.3 / (D) ^1/2 . This is obtained by multiplying the condition just before the application liquid on the upper part of the mold does not drop by gravity during the horizontal rotation of the mold by a safety factor. Conditions for this borderline is a condition that the gravitational acceleration g = 980 is balanced ω = 31.3 / ^{(D) 1/2} of the acceleration d [omega ² which determines the size of the coating liquid centrifugal force due to rotation of the mold (( Co., Ltd., “FRP molding practice”). Since the rotational speed R (rpm) of the mold is obtained from ω = 2π × 60 / R, the rotational speed R is set so as to satisfy the above relationship.

When the rotation of the mold is stopped after the endless film is dried and solidified, if the heating and drying of the endless film are insufficient, the endless film flows and causes dripping and unevenness in film thickness. In order to prevent this, the rotation of the mold may be stopped after the endless film is completely dried and solidified, but the heating time is excessively longer than necessary to completely dry the endless film,
If the heating temperature is set too high, the production efficiency decreases. Further, if the endless film is excessively dried and solidified due to excessive heating, depending on the type of the mold, a problem arises in that the adhesive force to the mold surface is increased and the film is difficult to peel off and remove.

[0007] In order to solve such a problem, the dried and solidified state of the endless film is reduced by reducing the production efficiency due to excessive drying, preventing the film from peeling off and removing the mold, and by dripping the coating film due to insufficient drying. It has been desired to control the thickness to an optimum state without variation.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and it is an object of the present invention to reduce the drying state of a coating solution by lowering production efficiency due to excessive drying and peeling after molding. A method for setting an endless belt, a method for manufacturing an endless belt, and a method for manufacturing an endless belt that can be controlled to an optimum state without a demolding defect and without dripping of an application liquid or thickness variation due to insufficient drying. An object of the present invention is to provide an apparatus for manufacturing an endless belt.

[0009]

Means for Solving the Problems In order to achieve the above object, the invention of claim 1 is to apply a coating liquid in a cylindrical mold,
In a method for setting an endless belt in which an endless belt is manufactured by heating and drying and solidifying the coating solution, a ratio of a solid content weight of the coating solution per unit area in a coating region in the mold is measured. The heating condition of the coating liquid is set based on the measurement result.

The dry state of the coating solution is determined by the ratio of the solid weight in the coating solution. Therefore, if the ratio of the solid weight of the coating solution to be used is grasped in advance, the coating solution can be dried to a desired dry state. It is possible to estimate a suitable heating condition. Therefore, in the method for setting the production conditions in the method for producing an endless belt according to claim 1, the ratio of the solid content weight of the application liquid per unit area in the application region in the mold is measured, and based on the measurement result, By setting the heating conditions for the coating liquid, the coating liquid can be controlled to a desired dry state. As a result, the drying state of the coating liquid is reduced, and there is no deterioration in production efficiency due to excessive drying or peeling-off failure after centrifugal molding.
In addition, it is possible to control the coating liquid to an optimum state without dripping or thickness variation due to insufficient drying.

According to a second aspect of the present invention, there is provided the endless belt manufacturing method according to the first aspect, wherein the coating liquid per unit area when the coating liquid reaches a predetermined set temperature at the time of the heating from normal temperature. When the weight is W ₀ , the weight after heating is W, the ratio of the solid content weight of the coating liquid is γ, and the heating time after reaching the set temperature is t,

## EQU2 ## The heating time t is set based on the following relationship: W = W ₀ (α · exp (−βt) + γ).

According to a second aspect of the present invention, there is provided an endless belt manufacturing method.

From the relationship of W = W ₀ (α · exp (−βt) + γ), a heating time t after the coating liquid reaches a predetermined set temperature is set. Here, Equation 1 is an approximate expression representing a change in the weight of the coating liquid corresponding to the heating conditions. As described above, the drying state of the coating solution is determined by the ratio of the solid content weight in the coating solution. Can be estimated. Therefore, the heating condition t can be set using Equation 1.

According to a third aspect of the present invention, there is provided a method for producing an endless belt of a polyimide, comprising applying a polyimide precursor solution in a cylindrical mold, heating and drying and solidifying the solution to produce a polyimide endless belt. When the ratio of the solid content weight of the solution per unit area in the coating region in the mold is γ, the heating conditions are adjusted so that the ratio of the residual solvent in the solution after heating becomes 0.25γ or less. It is characterized by setting.

An experiment was conducted in which the coating solution was heated under various heating conditions, and it was found that, regardless of the initial solid content in the polyimide precursor solution, dripping due to insufficient drying and thickness variation did not occur. The level of dryness is such that the ratio of the solid content of the coating solution after drying to the residual solvent is 3: 1.
It turned out that it was time. Therefore, in this method for producing an endless belt, when the ratio of the solid content weight of the polyimide precursor solution is γ, the heating conditions are set so that the ratio of the residual solvent after heating is 0.25γ or less. This can prevent dripping of the solution and unevenness in thickness due to insufficient drying.

According to a fourth aspect of the present invention, there is provided a cylindrical mold to which a coating liquid is applied and used, and a heating means for heating the coating liquid with the coating liquid applied to the inner surface of the mold. In an endless belt manufacturing apparatus for manufacturing an endless belt by drying and solidifying the coating liquid by heating, a measuring means for measuring a ratio of a solid content weight of the coating liquid per unit area in a coating area in the mold; And control means for controlling the heating means so as to heat the coating liquid under heating conditions based on the measurement result measured by the measurement means.

In the apparatus for manufacturing an endless belt according to a fourth aspect of the present invention, the ratio of the solid content weight of the coating liquid per unit area in the coating area in the mold is measured by the measuring means, and the measurement is performed by the measuring means by the control means. The heating means is controlled so as to heat the coating solution under heating conditions based on the result. Since the drying state of the coating liquid is determined by the percentage of the solid content weight in the coating liquid, if the percentage of the solid content weight of the coating liquid to be used is measured, the heating conditions are such that the coating liquid is in a desired dry state. It can be controlled to heat the coating liquid. As a result, the drying state of the coating liquid is controlled to an optimum state without a decrease in production efficiency due to excessive drying, a peeling-off failure after centrifugal molding, and no dripping of the coating liquid due to insufficient drying and thickness variation. can do.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below by using a centrifugal molding method to form an endless transfer which is a carrier for a toner image or a transfer material in an image forming apparatus such as an electrophotographic copying machine, a facsimile, and a printer. One embodiment applied to the case of manufacturing a belt will be described.

First, the centrifugal molding method according to the transfer belt manufacturing method of the present embodiment will be described. In the present embodiment, a transfer belt using polyimide as a basic material is formed. FIG. 1 shows a part of an endless transfer belt manufacturing apparatus using a centrifugal molding method.
Endless film 2 for a transfer belt formed on the inner peripheral surface of
FIG. The chain line in the figure indicates the rotation axis 3 of the mold 1 in the centrifugal molding process. The endless film 2 is obtained by forming a coating liquid as a belt material on the inner peripheral surface of the mold 1 by a centrifugal molding method. In the present embodiment, a polyamic acid solution was used as a coating liquid. Polyamic acid has a property of being converted into polyimide by imide ring closure by heat or a catalyst. Polyamic acid solution, polyimide precursor solution,
NN dimethylacetamide (hereinafter referred to as D)
MAC). In this embodiment, polyimide is used as a basic material of the transfer belt, but the present invention is not limited to this.

In FIG. 1, an endless film 2 is formed on the inner peripheral surface of a mold 1 by a known centrifugal molding technique. Specifically, a polyamic acid solution as the above-mentioned coating solution is applied to a mold 1, and the mold 1 is rotated at a high speed of 1000 rpm to form an endless film 2 having a predetermined thickness.

Next, while rotating the mold 1, the endless film 2 formed as described above is heated by a heating means (not shown) to evaporate the solvent DMAC in the polyamic acid solution to dry and solidify the endless film 2. Let it. Then, in order to finally finish the endless film 2 into a polyimide belt, the endless film 2 made of a polyamic acid solution is heated to close the imide ring and to perform a curing treatment. Thereafter, after cooling, the transfer belt made of polyimide as a base material is obtained by peeling off the mold 1 and removing the mold.

Here, in the above-mentioned centrifugal molding method, when the rotation of the mold 1 is stopped after the endless film 2 is dried and solidified,
When the heating and drying of the endless film 2 are insufficient, the endless film 2 flows to cause dripping and unevenness in film thickness. On the other hand, if the heating time is made too long or the heating temperature is too high in order to completely dry the endless film 2 in order to prevent this, the production efficiency will be reduced. Also, if the endless film 2 is excessively dried due to excessive heating, depending on the type of the mold 1, the adhesive force to the mold surface is increased, and it becomes difficult to peel and remove the film. In order to solve such a problem, the drying state of the endless film 2 must be adjusted so that there is no decrease in production efficiency due to excessive drying and there is no defective peeling and demolding of the film. It is desirable to control to an optimal state without any.

Here, the lowest level of the dry state in which the endless film does not drip due to insufficient drying and the thickness variation does not occur is empirically determined to be a degree to which a so-called "touch dry" feels sticky when lightly touched with a finger. I know that Therefore, if the endless film is dried to the touch drying level and then subjected to a curing treatment in another heating furnace, the drying state of the endless film 2 may cause a decrease in production efficiency due to excessive drying or a defect in peeling and demolding of the film. It is possible to control to an optimum state without any dripping of the endless film due to insufficient drying and no variation in film thickness.

Therefore, in order to find a method of controlling the endless film to the touch dry level, the present inventors used a polyamic acid solution in which the ratio of solid content was changed variously, and heated the solution at a heating temperature and a heating time. An experiment was performed in which the heat treatment was performed while changing the respective conditions. When the weight analysis of the heated polyamic acid solution was performed, it was found that when the solution reached the dry-to-touch level, the solid content weight of the solution and the residual solvent weight were in a certain ratio. I found it. The details and results of the experiment will be described below.

[Experiment 1] A polyamic acid solution having variously changed solid contents was prepared, and subjected to heat treatment using a thermogravimetric analyzer while changing a heating temperature and a heating time, respectively. The weight of the solid content of the solution and the weight of the residual solvent were measured, and each dried state was actually confirmed by touching with a finger. FIG. 2 is a graph showing a drying state of the polyamic acid solution with respect to a heating condition. The vertical axis shows the heating temperature (° C.), and the horizontal axis shows the heating time (min). Also, in the figure ○
Does not stick even when touched with a finger, that is, the coating liquid is in a dry state at or above the touch dry level.
It indicates that the coating liquid is in an insufficiently dried state by touching with a finger. From the graph, it can be seen that the higher the heating temperature and the longer the heating time, the larger the amount of the solvent DMAC evaporated, and the faster the touch-dry state is reached.
And, as a result of performing each weight analysis after heating, regardless of the ratio of the solid content weight of the initial polyamic acid solution,
Upon reaching the touch dry level, it was found that the solids weight and residual solvent weight of the solution were in a 3 to 1 ratio.
In other words, in order to dry the polyamic acid solution to a touch dry level or higher, the proportion of the solid weight in the solution should be γ.
Then, heating and drying may be performed until the ratio of the residual solvent weight becomes 0.25γ or less.

If the ratio of the solid content weight of the polyamic acid solution per unit area in the coating area in the mold 1 is known from the result of the above experiment 1, when the touch-dry state is obtained,
It is possible to estimate how much solvent should be evaporated until the ratio of the residual solvent weight in the coating liquid becomes 0.25γ with respect to the solid content ratio γ. Therefore, for example, if the relationship between the heating conditions of the polyamic acid solution and the evaporation amount of the solvent is determined in advance by experiments or the like, it is possible to set the heating conditions such that the polyamic acid solution is dried to the touch dry level.

[Experiment 2] Next, using the same polyamic acid solution and the thermogravimetric analyzer as in Experiment 1, the change over time of the solution weight was measured while heating the solution at a predetermined heating temperature. The results will be described. FIG. 3 is a graph showing a change in weight with respect to heating time when the polyamic acid solution is heated at the following three temperatures. The vertical axis is the weight of the polyamic acid solution (arbitrary unit), and the horizontal axis is the heating time t (min).
Is shown. The heating time t = 0 (min) in the graph is the time when the polyamic acid solution at room temperature was heated and reached the predetermined temperature, and the graph shows the weight change in the state where the polyamic acid solution was maintained at the predetermined temperature. Represents. The heating temperature is indicated by the solid line a.
150.degree. C., 100.degree. C. of the wavy line b, and 70.degree. C. of the dashed line c. The graph shows that the change in the polyamic acid solution weight changes exponentially from the initial weight with respect to time t. Finding the regression equation,

W = W ₀ (α · exp (−βt) + γ) W ₀ : weight of polyamic acid solution per unit area after reaching a predetermined temperature, α: proportionality constant, β: decay rate with respect to time (hour Constant), γ: solid content ratio, and it was found that this formula can be sufficiently approximated with reproducibility. The graph also shows that the constant β is a function of the heating temperature T, and the constant β increases as the heating temperature T increases. And the value of the constant β obtained from the experimental results is
It was also found that the solvent and DMAC correspond well to the saturated vapor pressure at the respective heating temperatures T, which is supported by Clausius's theoretical formula of the relationship between the heating temperature T and the saturated vapor pressure.

The weight W of the polyamic acid solution at the touch dry level was determined from the result of Experiment 1 above.

## EQU5 ## It can be expressed by W = 1.25W ₀ · γ. Therefore, from the above equations 1 and 2,

W ₀ (α · exp (−βt) + γ) = 1.25 W ₀ · γ can be derived, and from Equation 3, heating from reaching a predetermined set time to reaching the touch dry level Time t is

## EQU7 ## t = -ln (0.25γ / α) / β

As is apparent from the above equation (4), the constant α and the constant β corresponding to the heating temperature are determined in advance by experiments, and if the solid content ratio γ of the polyamic acid solution is known, the predetermined set time is reached. After that, the heating time t until the touch dry level is reached can be determined.

Next, the endless film 2 (see FIG. 1) of the polyamic acid solution actually formed by centrifugal molding was dried by heating.
The result of evaluating the dry state will be described. This evaluation is performed by heating the endless film 2 inside the rotating mold 1 by changing the heating time to be described later, and observing the dry state of the endless film 2 when the rotation of the mold 1 is stopped after the heating. It is a thing. Further, the dried endless film 2 was then reheated in another heating furnace at 300 ° C. for 30 minutes to perform a hardening treatment, and the state of film formation after peeling off from the mold 1 was also evaluated. As the polyamic acid solution, a solution obtained by diluting a polyimide precursor solution to 30% with DMAC was used. The solid content of the solution was 15% (γ = 0.15), and the specific gravity was 1.4.
It is.

In FIG. 1, a mold 1 having an inner diameter of 180 mm
By rotating at a high speed of 000 rpm, an endless film 2 made of the above polyamic acid solution was molded. The coating width was 500 mm except for a member (height: 2 mm) for blocking the solution (not shown) arranged at both ends of the inner peripheral surface of the mold 1.
The liquid thickness was 900 μm for 00 μm.

From an experiment of thermogravimetric analysis, α = 0.2
07, β = 0.711 (T = 70 ° C.), β = 0.13
1 (T = 100 ° C.), β = 0.2135 (T = 150
° C), and from the above equation (4), the time t at which the polyamic acid solution reaches the touch dry level in this case is 24 minutes (T = 70 ° C), 13 minutes (T = 100 ° C), and 8 minutes (T = 100 ° C). T =
150 ° C.). In this evaluation, the heating temperature was set to 100 ° C., and the heating time was changed within a range close to 13 minutes, which is the heating time obtained from Equation 4 above, and heating was performed.

Table 1 below shows the evaluation results.

[Table 1]

As shown in Examples 1 to 3 in Table 1, when the heating time is 15 to 20 minutes longer than the heating time of 13 minutes obtained from the above equation 4, the dripping and the variation in the film thickness are also reduced. It was found that the film was in a good dry state, and that the endless film 2 after the curing treatment was easily formed and the mold was easily peeled off from the mold 1. On the other hand, as shown in Comparative Examples 1 and 2 in Table 1, when the heating time was 5 minutes or 10 minutes shorter than 13 minutes, when the rotation of the mold 1 was stopped, the film flow-deformed. Further, during the reheating, the film was not uniformly cured by the flow deformation, and a part of the film floated and shrunk.

As described above, according to this embodiment, the ratio of the solid content weight of the polyamic acid solution per unit area in the coating region in the mold is measured, and the heating condition of the solution is set based on the measurement result. This makes it possible to control the solution to dry to the touch. Accordingly, it is possible to control the production state to an optimum state without a decrease in production efficiency due to excessive drying or a peeling / demolding defect after molding, and without dripping of the coating liquid or thickness variation due to insufficient drying. Further, since the heating conditions can be set based on the ratio of the solid content weight of the polyamic acid solution measured in advance, the heating and drying step of the polyamic acid solution can be automated.

In the above embodiment, the transfer belt manufacturing apparatus includes a measuring means for measuring the ratio of the solid content weight of the polyamic acid solution per unit area in the coating area in the mold, and a measuring means for measuring the ratio. Control means for controlling the heating means may be provided so as to heat the solution under the heating conditions based on the measured result, thereby controlling the solution to a touch-dry state. FIG. 4 is a block diagram showing an example of a configuration of a control system for controlling the heating means. This control system includes a control device 100 as control means including a CPU, a RAM, a ROM, an I / O interface, and the like. The control device 100 is connected with a measuring device 101 as a measuring means for measuring the ratio of the solid content weight of the polyamic acid solution per unit area in the application region in the mold, and a signal from the measuring device 101 is input. You. Further, the control device 100 includes a heating heater 10 as heating means for heating the polyamic acid solution applied in the mold.
2 are connected. In this control system, the measuring device 1
01 under the heating condition according to the signal from
2 heats the polyamic acid solution. By controlling the heater 102 in this manner, the polyamic acid solution can be brought into a touch-dry state according to the ratio of the solid content weight of the polyamic acid solution per unit area in the application region in the mold.

In the present embodiment, the case where a polyamic acid solution is used as a coating solution and the solution is controlled to a dry state at a touch dry level has been described as an example, but the present invention is not limited to this. Even when the drying state of the coating liquid to be used or the target used is different, the ratio of the solid content weight per unit area in the coating area of the coating liquid to be used is measured,
By setting heating conditions for the coating liquid based on the measurement result, the coating liquid can be controlled to a desired dry state. As for the setting of the heating conditions, as shown in the above-described Experiment 1, the relationship between the amount of solvent evaporation and the heating conditions obtained in advance through experiments or the like is set in a data table, and the heating conditions are set with reference to the data table. Alternatively, as shown in the above Experiment 2, an approximate expression representing a change in the weight of the coating liquid corresponding to the heating conditions as shown in Equation 1 above is obtained, and further, the coating liquid after heating so as to obtain a desired dry state. The heating condition may be set by previously obtaining the weight W for each application liquid to be used.

In this embodiment, the case of forming the transfer belt used in the image forming apparatus has been described as an example. However, the present invention is not limited to this, and the formation of the endless belt used in various belt apparatuses is described. Method can be applied.

[0038]

According to the first and second aspects of the present invention, the ratio of the solid content weight of the coating solution per unit area in the coating region in the mold is grasped in advance, and the coating solution is brought into a desired dry state. By setting such heating conditions, the coating liquid can be controlled to a desired dry state. As a result, the drying state of the coating liquid is controlled to an optimum state without a decrease in production efficiency due to excessive drying, a peeling-off failure after centrifugal molding, and no dripping of the coating liquid due to insufficient drying and thickness variation. can do. Further, since the heating condition is set based on the ratio of the solid content weight of the coating liquid measured in advance, there is an effect that the heating and drying step of the coating liquid can be automated.

In particular, according to the second aspect of the present invention, the weight W of the coating solution after heating to obtain a desired dry state is determined from the ratio γ of the solid content weight of the coating solution to be used.
Can be used to set a heating time t after the coating liquid reaches a predetermined set temperature.

According to the third aspect of the present invention, when the ratio of the solid content weight of the polyimide precursor solution is γ, the ratio of the residual solvent in the solution after heating is 0.25γ or less.
By setting the heating condition of the solution, there is an excellent effect that dripping of the solution and variation in thickness due to insufficient drying can be prevented.

According to the fourth aspect of the present invention, the ratio of the solid content weight of the coating solution per unit area in the coating region in the mold is measured in advance, and the heating condition is such that the coating solution is brought into a desired dry state. By controlling the coating liquid to be heated, the coating liquid can be controlled to a desired dry state.
As a result, the drying state of the coating liquid is controlled to an optimum state without a decrease in production efficiency due to excessive drying, a peeling-off failure after centrifugal molding, and no dripping of the coating liquid due to insufficient drying and thickness variation. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a method of manufacturing an endless belt by a centrifugal molding method according to an embodiment.

FIG. 2 is a graph showing a drying state of a coating solution with respect to a heating condition.

FIG. 3 is a graph showing a change in weight of a coating solution with respect to a heating time.

FIG. 4 is a block diagram showing one configuration example of a control system of a heater.

[Explanation of symbols]

 1 type 2 endless film 100 control device 101 measuring device 102 heater

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H032 BA09 BA18 DA13 4F213 AA40 AG16 AH33 AP14 AR06 AR11 AR20 WA03 WA53 WA58 WA83 WA97 WB01 WC03 WF24

Claims (4)

[Claims] An endless belt manufacturing method for manufacturing an endless belt by applying a coating solution in a cylindrical mold and heating and drying and solidifying the coating solution to produce an endless belt. A method for setting conditions for producing an endless belt, comprising: measuring a ratio of a solid content weight of a coating solution per unit area in a coating region, and setting heating conditions of the coating solution based on the measurement result. 2. The method of setting endless belts according to claim 1, wherein the weight per unit area when the coating liquid reaches a predetermined set temperature at the time of heating from normal temperature is represented by W ₀ , If the weight after heating is W, the ratio of the solid content weight of the coating liquid is γ, and the heating time after reaching the set temperature is t, W = W ₀ (α · exp (−βt) + γ The method for setting the manufacturing condition of the endless belt, wherein the heating time t is set from the relationship of (1). Where α: proportionality constant, β: time-dependent decay rate (time constant) 3. A method for producing an endless belt of a polyimide, comprising applying a polyimide precursor solution in a cylindrical mold, heating and drying and solidifying the solution to produce an endless belt of polyimide. Assuming that the ratio of the solid content weight of the solution per unit area in the application area is γ, the heating conditions are set so that the ratio of the residual solvent in the solution after heating is 0.25γ or less. A method for producing an endless belt. 4. A cylindrical mold to which a coating liquid is applied and used, and heating means for heating the coating liquid in a state where the coating liquid is applied to the inner surface of the mold, wherein the heating causes the coating liquid to be heated. In an endless belt manufacturing apparatus for manufacturing an endless belt by drying and solidifying, the measuring means for measuring the ratio of the solid content weight of the coating liquid per unit area in the coating area in the mold, and the measuring means An endless belt manufacturing apparatus, comprising: a control unit for controlling the heating unit so as to heat the coating liquid under heating conditions based on the measured measurement result.