JP3856629B2 - Manufacturing method of endless belt - Google Patents

Description

【００７４】
【表２】

【図面の簡単な説明】
【図１】 本発明に係る無端状ベルトの製造方法の実施の一形態に用いられる製造装置を示す軸方向概略断面図である。
【図２】 本発明に係る無端状ベルトの製造方法の実施の一形態の各工程を示すフローチャートである。
【図３】 ぬれ性を有しない堰き止め部材にベルト原料の端部がはじかれている様子を示す拡大断面図である。
【図４】 ぬれ性を有する堰き止め部材にベルト原料の端部が接触し、密着する様子を示す拡大断面図である。
【図５】 本発明に係る無端状ベルトの製造方法の他の実施の形態に用いられる製造装置を示す軸方向概略断面図である。
【符号の説明】
１…塗布型（ベルト製造用金型）
２…離型層
３…堰き止め部材（リング）
３ａ…穴部
４…塗布膜（ベルト原料，ベルト）
４ａ…端部
５…塗布型保持部材
６…ヒータ
７…ヒューム
８ａ…光源
８ｂ…センサ
９…肉眼[0001]
BACKGROUND OF THE INVENTION
The present invention is a copying machine, a printer, a method of manufacturing an endless belt for use in an image forming equipment such as a facsimile.
[0002]
[Prior art]
Conventionally, in image forming apparatuses such as copying machines, printers, facsimiles, etc., a so-called intermediate transfer belt as an intermediate toner carrier for an electrostatic copying process or a fixing belt for fixing toner on a recording paper is seamless. An endless belt is used. This endless belt is manufactured by various methods. For example, in the centrifugal molding method, a fluid belt material is sprayed on the inner peripheral surface of a hollow cylindrical coating mold as a mold for manufacturing the belt. By applying and rotating the coating mold at high speed around the central axis of the cylinder, the belt raw material is uniformly stretched by the generated centrifugal force to form a uniform belt film (coating film), and then the coating film is dried and solidified. By taking out, a seamless endless belt having a cylindrical shape is formed.
[0003]
In this centrifugal forming method, the film thickness can be adjusted arbitrarily by adjusting the coating amount, and it is sufficient to apply the required amount of belt raw material, so that the raw material efficiency is good. By providing a solvent trap in the path, there is an advantage that the solvent discharged to the outside when the solvent is removed can be efficiently recovered.
[0004]
However, in the drying process and heat curing process after coating the belt material, adhesion between the inner surface of the coating mold and the belt material that has become the coating film is required, and in the demolding process of removing the coating film from the coating mold, the coating mold Since releasability between the inner surface and the coating film is required, there is a drawback that it is difficult to satisfy both requirements.
[0005]
Here, the process of drying the belt material to the touch-dried coating film is called the drying process, and the coating film in the touch-dried state is further heated to be almost completely dried and cured. This is called a process.
[0006]
For example, when glass or a fluororesin-based material is used as a release material for the inner surface of the coating mold, the belt raw material and the inner surface of the coating mold maintain the adhesion until the belt raw material is dry to the touch in the drying process. However, when entering the curing reaction stage in the heat curing process, there is a problem that the end of the coating film is lifted off from the coating mold, and a belt having a uniform diameter cannot be obtained.
[0007]
When the coating film is dried to the touch dry state, the coating film is removed from the coating mold, and a cylindrical member having an outer diameter substantially the same as the inner peripheral length of the coating film is inserted into the hollow inside of the coating film to be cured by heating. Although there is a method, in this method, the number of steps is increased, and when the air enters between the coating film and the cylindrical member, the coating film is deformed into a convex shape.
[0008]
Further, at this time, in order to facilitate the insertion of the cylindrical member, if the gap between the outer diameter and the inner surface of the coating film is increased, shrinkage due to drying becomes uneven and wrinkles occur, and conversely the gap is reduced. If the amount is too large, the residual solvent cannot be sufficiently evaporated, resulting in insufficient drying.
[0009]
The present inventors pay attention to the fact that the floating of the coating film from the coating mold at the time of heat curing occurs from the coating film end, and insert the ring-shaped coating film pressing member from the coating mold end to remove the coating film. Previously devised a means to hold onto the application mold and prevent floating. According to this means, the coating film end is pressed by the coating film pressing member and the coating mold, so that a good coating film can be obtained without causing floating.
[0010]
[Problems to be solved by the invention]
However, in this method, if there is a gap between the coating film pressing member and the coating film due to a shift in the setting position of the coating film pressing member, there is a case where floating occurs at that portion. Further, when the film thickness of the coating film end is increased due to aggregation of the belt raw material, the coating film end may be destroyed when the coating film pressing member is inserted.
[0011]
Without using a coating film holding member, by lowering the releasability of the part near the axial end than the part near the axial center of the inner surface of the coating mold, There is also a method of obtaining a good coating film while preventing the coating film edge from floating, but this method has different releasability between the portion near the end of the coating mold inner surface and the portion near the center. There is a problem that complicated processing must be performed, and the production cost of the coating mold increases. Furthermore, since a chemical treatment solution is used for the treatment having releasability, post-treatment such as disposal of the chemical treatment solution becomes a problem when a plurality of treatments are performed.
[0012]
The present invention has been made in view of the above circumstances, the drying in step and heat curing process generates no floating or shrinkage, endless wrinkles without or deformation good endless belts can be conveniently obtained it is an object of the present invention to provide a manufacturing how the belt.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the present onset Ming, endless by coating the belt material in the interior of the coating type hollow cylindrical shape having a releasability on the inner surface, performing centrifugal molding by rotating the coating type The belt raw material contains two types of solvents having different boiling points, and after the start of generation of fumes by the solvent having the higher boiling point among the solvents, the fumes It is characterized in that the drying process is stopped before the generation of is finished .
[0022]
According to the present invention, the drying process is stopped after the start of the generation of fumes by the solvent on the high boiling point side and before the end of the generation of fumes. Therefore, there is no dripping due to insufficient drying, and there is no occurrence of floating or deformation of the coating film due to overdrying.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a method for producing an endless belt according to the present invention will be described with reference to the drawings.
[0028]
FIG. 1 is a schematic cross-sectional view in the direction of the rotation axis of a manufacturing apparatus used in the method for manufacturing an endless belt according to the present invention. In FIG. 1, reference numeral 1 denotes a coating mold as a belt manufacturing mold having a substantially hollow cylindrical shape. The endless belt according to the present invention is manufactured by applying a belt raw material to the hollow inner surface of the coating die 1 and performing centrifugal molding.
[0029]
The endless belt is used as a transfer belt for transferring the toner to the recording paper in the image forming apparatus or a fixing belt for fixing the toner to the recording paper, so that the surface of the endless belt does not affect the formed image. Is preferably smooth. When the adhesion between the hollow inner surface of the coating mold 1 and the belt raw material is high, kinks and wrinkles are generated on the surface of the coating film 4 in the demolding step of removing the belt raw material that has become the coating film 4 from the coating mold 1. I can't get a good belt. Therefore, a release layer 2 made of fluororesin or the like is formed on the hollow inner surface of the coating die 1 so that the molded belt can be easily taken out from the coating die 1.
[0030]
As shown in the flowchart in FIG. 2, first, the damming member 3 is fitted from both ends in the left-right direction in the drawing of the coating die 1 (S.1 damming member setting step). This damming member 3 is for preventing the belt raw material from leaking out, and has a ring shape in which the outer diameter is substantially the same as the hollow inner diameter of the coating die 1 and a hole 3a is formed in the center ( (Cylindrical shape) and made of a material having wettability to the belt material.
[0031]
When the damming member 3 is fitted, the coating die 1 is held by the coating die holding member 5 and rotated around the central axis of the cylinder by a rotating means (not shown) (S.2 rotation start step).
[0032]
Thereafter, a coating nozzle (not shown) is inserted into the coating mold 1 from the hole 3a of the damming member 3, and the belt material is coated inside the coating mold 1 (S.3 coating process).
[0033]
By adjusting the coating amount of the belt raw material, a desired belt size and thickness can be easily obtained. As will be described later, since the belt raw material contains two types of solvents, a low boiling point solvent having a low boiling point and a high boiling point solvent having a high boiling point, the dry state can be easily confirmed. Yes.
[0034]
Since the release layer 2 is formed on the inner surface of the coating die 1, the affinity with the belt material is low. For example, when the coating die 1 is stationary or the rotation speed is low, the belt material is agglomerated. However, in this case, since the coating mold 1 rotates at a high speed, the belt raw material does not aggregate and is uniformly stretched on the inner surface of the coating mold 1 (S.4 stretching process).
[0035]
The high speed rotation of the coating die 1 is continued as it is, the belt raw material is stretched toward the end of the coating die 1 and is brought into contact with and closely contacted with the damming member 3 fitted to the end of the coating die 1 (S. 5 adhesion process).
[0036]
At this time, for example, if the damming member 3 does not have wettability to the belt material, the belt material is repelled by the damming member 3 and does not adhere as shown in FIG. As a result, the end 4a of the coating film 4 made of the belt raw material floats from the coating mold 1 in the drying process and heat curing process described later. However, in the present embodiment, the damming member 3 has wettability with respect to the belt raw material, and as shown in FIG. Even in the heat curing step, the end 4a of the coating film 4 made of the belt material does not float from the coating mold 1.
[0037]
Next, the belt material heated by the heater 6 disposed in the vicinity of the coating die is dried while the coating die is rotated (S.6 drying step).
[0038]
If the solvent in the belt raw material evaporates due to drying and the volume of the solvent content in the belt raw material decreases, the surface energy of the belt raw material that has already been stretched may increase and agglomeration / degeneration may occur again. In the embodiment, since the belt material end is in close contact with the damming member 3 and the belt material is kept rotating at high speed until the belt material is in a dry-to-touch state in the drying process, the belt material does not cause cohesion.
[0039]
In order to improve the productivity of the belt, it is preferable that the drying time is short. Therefore, a solvent having a low boiling point which is quickly dried is included in the belt raw material. However, it is difficult to grasp the dry state with only a low-boiling solvent, and the drying is fast, so that it tends to be overdried. The coating film 4 that has become overdried may float from the coating mold 1 and cause wrinkling or deformation of the belt. Therefore, in this embodiment, the belt raw material contains two kinds of solvents, a low boiling point solvent and a high boiling point solvent.
[0040]
Since the belt raw material contains two kinds of solvents, a low-boiling side solvent and a high-boiling side solvent, the heating of the heater 6 first causes the low-boiling side solvent to start to evaporate. Further, when the temperature of the belt raw material rises, the solvent on the high boiling point side also starts to evaporate, and fumes 7 are generated inside the coating mold.
[0041]
This fume 7 is generated after the evaporation of the solvent on the high boiling point side has started and when it is below the boiling point temperature. Before the fume 7 is generated, the belt raw material is not yet dry to the touch and is not sufficiently dried. If the coating mold 1 stops rotating, dripping may occur. On the other hand, after the generation of the fumes 7, the coating film 4 may be lifted from the coating mold 1, but if the fumes 7 are generated, the belt raw material is just the coating film 4 in a dry-to-touch state. Yes. For this reason, it is necessary to stop the drying while the fume 7 in which the coating film 4 is in the dry-to-touch state is generated.
[0042]
In the present embodiment, a light source 8a and a sensor 8b are arranged in the vicinity of both ends of the coating mold 1 in the rotation axis direction by utilizing the fact that the light transmittance inside the coating mold 1 is reduced when the fumes 7 are generated. The presence or absence of the fumes 7 inside the coating mold 1 is detected through the hole 3a of the stop member 3 (S.7). When the light intensity detected by the sensor 8b decreases, it is determined that the fumes 7 are being generated and the drying is stopped, so that the liquid does not drip and does not float from the coating mold 1. The coating film 4 in a state can be obtained (S.8).
[0043]
After detecting the fume 7, the heater 6 is stopped, and the rotation of the coating die 1 is also stopped, the coating die 1 is moved to a heating furnace (not shown) while the coating film 4 and the blocking member 3 are held inside. Then, heating is performed again in a heating furnace to completely dry the coating film 4 (S.9 heat curing step).
[0044]
At this time, since the end portion 4a of the coating film 4 is in close contact with the damming member 3, the coating film 4 does not float from the coating mold 1 and does not cause wrinkles or deformation.
[0045]
When the curing of the coating film 4 is completed (S.10), the coating film 4 that has become a belt is removed from the coating mold 1 (S.11 demolding step). In this case, the belt 4 may be removed from the coating die 1 after the damming member 3 is first removed from the coating die 1, but in this embodiment, the belt 4 and the belt 4 from the axial end of the coating die 1. The damming member 3 is removed together. Since the release layer 2 is formed on the hollow inner surface of the coating die 1, the belt 4 can be smoothly removed from the coating die 1 without sticking to or catching on the inner surface of the coating die 1.
[0046]
The damming member 3 is removed from the removed belt 4 to obtain the belt 4 (S.12).
[0047]
In the present embodiment, the coating mold holding member 5 is arranged on both sides in the axial direction of the coating mold 1 and is held and rotated. However, it is arranged only on one side in the axial direction and cantilevered as shown in FIG. May be rotated. As a result, the number of parts on the side where the coating type holding member 5 is not provided is reduced, and a space is created. Therefore, the presence or absence of the fumes 7 can be confirmed visually with the naked eye 9 without using the light source 8a and the sensor 8b.
[0048]
In the drying step, the drying temperature of the portion of the coating film (belt raw material) 4 near the rotation axis direction end 4a may be lower than the drying temperature of the portion near the rotation axis direction central portion. Thereby, the drying of the part near the end 4a of the coating film 4 can be delayed from the drying of the part near the central part of the coating film 4, and the coating film 4 can be lifted from the coating mold 1 by overdrying. Further, it can be effectively prevented and the occurrence of wrinkles and deformation of the coating film 4 can be prevented.
[0049]
[Example 1]
A release layer was formed by performing fluororesin (PFA) coating treatment on the entire inner surface of a hollow cylindrical aluminum coating mold having an inner diameter of 60 mm. A polyamide as a damming member of PTFE (product name: manufactured by Naflon Nichias) is fitted to both ends of the coating mold so as to be in close contact with each other, and polyamide is preliminarily rotated while rotating at 1000 rpm at a cantilever (holding one side of the coating mold). A belt raw material prepared by diluting an imide stock solution (containing N-methylpyrrolidone NMP (boiling point 202 ° C.) in the stock solvent) in toluene (boiling point 110.6 ° C.) was applied.
[0050]
The coated belt material was uniformly stretched and reached and closely attached to the rings fitted at both ends of the coating mold, and then dried with a heater while rotating, and then stopped rotating.
[0051]
Table 1 summarizes the results of observing the state of the belt material (coating film) after drying with various drying temperatures and drying times.
[0052]
In addition, the heating at the time of drying was performed with an external heater arranged in the vicinity of the outside, and the temperature at both ends was adjusted to be 5 ° C. lower than the center temperature.
[0053]
Thereafter, a sample with no dripping or floating was transferred to a thermostat as a heating furnace and heated at 200 ° C. for 30 minutes to completely remove the solvent.
[0054]
If the ring at both ends was removed and the one end of the belt membrane was pulled after standing cooling, it could be pulled out from the coating mold. In addition, the central portion of the belt film was glossy on the outer surface in contact with the inner surface of the coating mold, and an extremely smooth surface was obtained, and there was no deformation such as wrinkles.
[0055]
If the temperature difference between the both ends and the center is up to about 10 ° C, the film could be formed without any problem. However, if the temperature difference exceeds 10 ° C, the drying time at both ends becomes extremely long, and both ends are dry to the touch. By the time, wrinkles occurred in the center.
[0056]
[Example 2]
Using the same coating mold and belt raw material as used in Example 1, the dam was fitted to the coating mold in the same manner, and the coating mold was fixed from both ends and held at both ends. Drying after coating is performed in the same manner as in Example 1 while measuring the light intensity by installing a light-emitting light source near the upper end of one axial extension line of the coating type and a light receiving unit near the upper end of the other axial extension line. I did it.
[0057]
If the light intensity does not decrease, that is, if drying is stopped before fume has yet to be generated, liquid dripping will occur, and after the light intensity has once decreased and increased again, that is, after fumes have been generated. When drying was stopped, the coating film was floating. Thereby, it turns out that generation | occurrence | production and extinction of a fume respond | correspond with the grade of the drying of a coating film. Therefore, in order to obtain a touch-dried coating film that does not drip and does not float from the coating mold, drying is stopped during the generation of fumes, that is, when the light intensity detected by the light receiving unit is reduced. It is necessary to make it.
[0058]
[Example 3]
N, N-dimethylacetamide DMAC (boiling point: 166.1 ° C.) is diluted to 10% in a polyamideimide stock solution that does not contain a high-boiling solvent to form a belt material. When set and coated and dried, fumes were generated and similar results were obtained.
[0059]
[Comparative Example 1]
Table 2 shows the results of drying using the same coating mold and belt raw material as used in Example 1 and adjusting the heating temperature at both ends to be the same as that in the central portion. From the results shown in Table 2, it can be seen that the condition range in which a film can be satisfactorily formed without the occurrence of floats and wrinkles is considerably narrower than that in Example 1.
[0060]
[Comparative Example 2]
Without using a ring as a damming member in the coating mold of the high releasable film as in Examples 1 and 2, using the same belt material solution as in Example 2, the coating mold was rotated at 1000 rpm. It was spun and applied. Even at the same rotation speed, stretching in the axial direction and contact with the inner surface of the coating mold were possible.
[0061]
Thereafter, heating was performed at 80 ° C. and drying was performed. As the drying progressed, the coating film was separated from the inner surface of the coating mold from the end portion, and the end portion floated after the heat treatment, and a good film could not be formed.
[0062]
[Comparative Example 3]
A ring as a damming member is provided on the coating mold of the high releasable film similar to that in Examples 1 and 2, and the coating mold is rotated at a rotational speed of 500 rpm using the same belt raw material liquid as in Example 2. And applied. It was possible to stretch in the axial direction and contact the ring even at the same rotation speed.
[0063]
Thereafter, drying was performed by heating at 80 ° C., and as the drying progressed, the coating film was separated from the ring from the end portion, and the end portion was lifted after the heat treatment, and a good film could not be formed.
[0064]
[Comparative Example 4-1]
Using the same coating mold as in Example 1 and a ring as a damming member, the polyamideimide stock solution of Example 1 was applied using a coating solution diluted with the solvent DMAC, and dried by heating at 80 ° C.
[0065]
Fumes were generated around 30 minutes after the start of drying, and the heating was stopped at 35 minutes and the solvent was removed by placing in a heating furnace, but it was found that the film dripped from the ring portion and the film thickness varied.
[0066]
[Comparative Example 4-2]
Using the same coating mold as in Example 1 and a ring as a damming member, the polyamideimide stock solution of Example 1 was applied using a coating solution diluted with the solvent DMAC, and dried by heating at 80 ° C.
[0067]
Although fumes were generated around 30 minutes after the start of drying, since the generation of fumes was completed in 50 minutes, when heating and rotation were stopped and the coating film was observed, it was observed that the film was floating.
[0068]
[Comparative Example 5]
N-methylpyrrolidone (boiling point 202 ° C.) of Example 3 Polyamideimide stock solution not containing high boiling point solvents such as NMP and DMAC was diluted with only toluene and applied, and the heating temperature was changed to 40-80 ° C. The film state was observed.
[0069]
There was no generation of fumes, the timing of stopping heating could not be grasped, the film was floated, and the liquid flow was caused by insufficient drying, so that stable process setting could not be performed.
[0070]
[Comparative Example 6]
In Example 1, when the drying process while rotating the coating mold was completed, the sample with a good dry-to-touch coating film was removed from the ring as a damming member after the coating mold stopped rotating. After removing from the coating film, it was put into a heating furnace.
[0071]
Although great care was taken when removing the ring, there were many phenomena in which the coating film was pulled by the ring to create a gap, and samples that were not abnormal in appearance also floated after heating in the furnace.
[0072]
【The invention's effect】
According to the present invention, it is possible to easily obtain a good endless belt that is free from wrinkling and deformation and does not float or shrink in the drying process or the heat curing process.
[0073]
[Table 1]

[0074]
[Table 2]

[Brief description of the drawings]
FIG. 1 is a schematic axial sectional view showing a manufacturing apparatus used in an embodiment of an endless belt manufacturing method according to the present invention.
FIG. 2 is a flowchart showing each step of an embodiment of the method of manufacturing an endless belt according to the present invention.
FIG. 3 is an enlarged cross-sectional view showing a state in which an end portion of a belt material is repelled by a damming member having no wettability.
FIG. 4 is an enlarged cross-sectional view showing a state in which an end portion of a belt material comes into contact with and adheres to a wetting member having wettability.
FIG. 5 is a schematic axial sectional view showing a manufacturing apparatus used in another embodiment of a method for manufacturing an endless belt according to the present invention.
[Explanation of symbols]
1 ... Coating mold (belt manufacturing mold)
2 ... Release layer 3 ... Damping member (ring)
3a ... hole 4 ... coating film (belt material, belt)
4a ... end 5 ... coating type holding member 6 ... heater 7 ... fume 8a ... light source 8b ... sensor 9 ... naked eye

Claims (1)

A method for producing an endless belt in which a belt raw material is applied inside a hollow cylindrical coating mold having releasability on the inner surface, and centrifugal molding is performed by rotating the coating mold,
The belt raw material contains two types of solvents having different boiling points, and after the start of generation of fumes by the solvent having the higher boiling point among the solvents, and before the end of the generation of fumes, a drying step The manufacturing method of the endless belt characterized by stopping a belt.

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