JP5076797B2 - Annular seamless belt and manufacturing method thereof - Google Patents

Description

  The present invention relates to an annular seamless belt and a method for manufacturing the same.

  In an image forming apparatus such as an electrophotographic copying machine or printer, a thin resin belt is often used as a photosensitive member, an intermediate transfer member, a fixing belt, and the like. Since such a resin belt can be deformed, it is useful for reducing the diameter of the apparatus. If the resin belt has a seam, a defect due to the seam occurs in the output image, and therefore a seamless belt without a seam is preferable.

  The seamless belt is manufactured, for example, by a method in which a resin solution is applied to the outer peripheral surface or inner peripheral surface of a mold, the resin coating film is heated, and the resulting resin film is demolded. In particular, a seamless belt made of polyimide resin is a method in which a polyimide precursor solution is applied to the outer peripheral surface or inner peripheral surface of a mold, the resin coating is heated and dried and reacted, and the resulting resin film is demolded. Manufactured by. In general, a mold is used in such a manner that a release layer such as a plating film or a silicone resin film is formed on the resin solution coating surface in order to facilitate the removal of the resin film (for example, Patent Documents 1 to 3). In addition, the mold has an axial length substantially equal to the desired belt width, and several hundreds of molds are prepared for mass production and used repeatedly.

  However, since the end portion of the belt obtained by the conventional manufacturing method is not reinforced, when the belt is stretched over a plurality of rollers, the belt drive is caused by the low roundness and straightness of the rollers. At times, meandering in the belt width direction occurred. When the meandering occurred, the belt contacted surrounding parts, for example, a guide member for regulating the meandering of the belt, and the belt end face was cracked after a relatively short period of use, and the belt was damaged.

Thus, Patent Documents 4 and 5 propose that a reinforcing member different from the belt base material is attached to both ends of the belt. However, attaching a separate member with high accuracy has led to an increase in the cost of the component. Moreover, when considering the use site, there was a concern about the bleeding of the adhesive due to the application of heat. That is, the present situation is that a sufficient reinforcing effect cannot be obtained at a low cost.
Japanese Patent Laid-Open No. 1-156017 JP-A-6-23770 JP 2004-291367 A JP 2001-282017 A JP 2005-266519 A

  An object of the present invention is to provide an annular seamless belt that is sufficiently inexpensive and has sufficiently improved belt end strength.

  Another object of the present invention is to provide a method for producing an annular seamless belt that can produce an annular seamless belt with sufficiently improved belt end strength at a low cost with high productivity.

  The present invention relates to an annular seamless belt characterized in that reinforcing portions thicker than the belt base material are integrally provided at both ends of the belt base material.

The present invention also provides
The connected mold is constructed by continuously applying a resin solution from one end to the surface of a connected mold formed by connecting two or more mold units that can be connected / disconnected in the axial direction. Of an annular seamless belt that repeats a cycle in which a mold unit that has been applied at the end of one end side of the mold unit to be applied is cut off and a new mold unit is connected to the other end of the connected mold A method,
Before the mold unit is separated, the regulating member is pressed against the resin coating on the surface of the mold unit p to be separated and the mold unit q adjacent to the mold unit at the joint of the mold units. An endless portion on the mold unit q side of the resin coating film on the surface of the mold unit p and an end portion on the mold unit p side of the resin coating film on the surface of the mold unit q are regulated. The present invention relates to a method for manufacturing a belt.

In the annular seamless belt of the present invention, since the reinforcing portions are integrally provided at both ends of the belt base material, the belt end strength can be sufficiently improved at low cost.
According to the present invention, the mold has a connected structure, and the belt can be continuously manufactured by continuously applying the resin solution to the connected mold, so that the productivity is excellent.
According to the present invention, since the resin mold is continuously applied to the surface of the connection mold and the application is not interrupted, the film thickness of the obtained belt is relatively uniform.
According to the present invention, since the resin mold is continuously applied to the entire surface of the connection mold and the release layer is not exposed, damage due to defective peeling can be prevented.
According to the present invention, even if the belt is damaged due to peeling failure, only the mold unit in which the damage has occurred needs to be replaced.

<Annular seamless belt>
The annular seamless belt of the present invention (hereinafter sometimes simply referred to as “belt”) has reinforcing portions at both ends of a belt base material.

For example, as shown in FIG. 1, the belt 100 of the present invention has a reinforcing portion 102 at both ends in the width direction D ₁ of the belt base 101. FIG. 1 is a schematic sketch of the belt of the present invention.

  The reinforcing portion 102 is thicker than the belt base material 101, and is provided integrally with the belt base material 101. As a result, the belt end strength is sufficiently improved at low cost.

  The average thickness of the belt base material 101 and the reinforcing portion 102 may be appropriately set according to the use of the belt. For example, when used as a belt such as a fixing belt, a transfer belt, or a contact charging belt used in an electrophotographic image forming apparatus, the average thickness of the belt substrate 101 is preferably 20 to 1000 μm, particularly preferably 30 to 100 μm, and the reinforcing portion The average thickness of 102 is preferably 30 to 1500 μm, particularly preferably 40 to 200 μm.

Length in the width direction _{D 1} of the reinforcing portion 102 is not particularly limited, usually 1 to 15 mm, in particular 2 to 10 mm.

  A known resin can be used as the material constituting the belt base 101 and the reinforcing portion 102, and examples thereof include a thermosetting resin and a thermoplastic resin. Specifically, polyimide, polyamideimide, polyetherimide, polyamide, polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, and the like can be used. Among these, from the viewpoint of strength, heat resistance, durability, and dimensional stability, a polyimide resin, a polyamideimide resin, particularly a polyimide resin is preferable.

<Mold>
The mold used for manufacturing the belt of the present invention is for manufacturing an annular seamless belt by applying a resin solution on the surface, and two or more molds that can be connected / disconnected from each other in the axial direction. It has a connected structure formed by connecting mold units. The resin solution may be applied to the outer peripheral surface of the connection mold or may be applied to the inner peripheral surface. When the resin solution is applied to the outer peripheral surface of the connection mold, the mold unit constituting the connection mold may be a hollow body or a solid body. When the resin solution is applied to the inner peripheral surface of the mold, the mold unit constituting the connected mold is a hollow body.

  When two or more mold units making up a connection mold (hereinafter, simply referred to as “mold”) are prepared, they can be connected / disconnected from each other in the axial direction, for example, connected to both ends. The mold unit may be a mold unit that has a portion and has a shape in which the connecting portion at one end can be fitted to the connecting portion at the other end. The fitting is to achieve the coupling by fitting one convex portion into the other concave portion.

A specific example of such a mold unit is shown in FIG. FIG. 2 is a schematic configuration diagram showing an embodiment of a mold unit constituting the connection mold of the present invention, and shows a cross-sectional view passing through the mold unit axis.
The mold unit 1 shown in FIG. 2 has a convex portion 2 at one end and a concave portion 3 at the other end, and the convex portion 2 and the concave portion 3 have shapes that can be fitted to each other. Therefore, when a plurality of such die units are prepared, they can be connected / disconnected by fitting between the convex portions and the concave portions. Since the mold unit 1 has a hollow shape, the resin solution may be applied to the outer peripheral surface or the resin solution may be applied to the inner peripheral surface.

  The axial length X of the mold unit 1 corresponds to the axial length of the conventional mold and is substantially equal to the predetermined width Y for one annular seamless belt. The dimension Z in FIG. 2 is not particularly limited because it is determined depending on the intended use of the annular seamless belt to be obtained.

  The material constituting the mold unit is not particularly limited as long as it does not cause deformation even when heated during the production of the seamless belt. For example, aluminum, aluminum alloy, copper, steel, stainless steel and other metals, alumina, Ceramics such as silicon carbide, and heat resistant resins such as polyimide and polyamideimide are preferably used. Among these, aluminum is particularly preferably used from the viewpoints of market distribution, solvent resistance, thermal conductivity, strength, and the like. When manufacturing the metal mold unit, the molten metal is poured into a mold having a specific shape, cooled, and then subjected to cutting or the like. In particular, when aluminum is used, a pipe or bar may be formed into a predetermined shape by cutting, and since it has excellent machinability among metals, there is a feature that it is easy to process, and the mold production efficiency can be increased.

It is preferable that a release layer is formed on the resin solution application surface of the mold unit.
The material constituting the release layer is not particularly limited, and for example, it is used by coating a silicone resin, a fluorine-containing resin, or the like, or coating a silicone-based or fluorine-based release agent.

One embodiment of a connecting mold is shown in FIG. A connecting mold 10 shown in FIG. 3 is formed by connecting only five mold units 1 shown in FIG.
The number of mold units constituting the mold is not particularly limited as long as it is two or more, and may be, for example, about 2 to 10, particularly about 4 to 7.

<Method for producing annular seamless belt>
The annular seamless belt of the present invention can be produced by the following method for producing an annular seamless belt.
The manufacturing method of such an annular seamless belt includes a resin coating film forming step of continuously applying a resin solution from one end side to the surface of the connection mold. Thereby, application | coating of the resin solution with respect to a some mold unit can be performed continuously.

  The application method of the resin solution is not particularly limited as long as it can be applied from one end side in the axial direction to the connection mold, and usually a ring coating method, a blade coating method, a bar coating method, or a roll coating method is adopted. The ring coating method is preferred from the viewpoints that vertical coating is possible and that either external coating or internal coating is possible.

  In the ring coating method, a resin solution that discharges the resin solution at a uniform speed over the entire circumference of the mold while ensuring a predetermined gap with the application surface outside or inside the application surface to which the resin solution is to be applied. Application is performed using an annular slit head. The annular slit head for a resin solution may have a configuration integrated with a supply tank for storing and supplying the resin solution, or may have a configuration in which the supply tank is arranged outside.

  Applying a resin solution continuously means that when applying a resin solution from one end side to a connected mold consisting of a plurality of mold units, after the application of one mold unit, without interruption, This means that the application of the adjacent mold unit is continuously performed in the direction from the one end side to the other end side.

  By adjusting the thickness of the resin coating film in this step, the average thickness of the belt base material portion and the reinforcing portion in the belt can be adjusted.

  In the present invention, in such a resin coating film forming step, a mold unit in which the application at the end of the one end side is completed among the mold units constituting the connected mold while performing continuous application. And a cycle of connecting a new mold unit to the other end of the connecting mold is repeated. FIG. 4 shows an example of an embodiment when the resin solution is applied.

  FIG. 4 shows the above-mentioned mold units constituting the coupled mold while continuously applying the resin solution 4 from one end A to the coupled mold 10 in which five mold units are coupled. FIG. 2 is a schematic diagram showing a state in which a mold unit 1 a at the end of one end is cut off and a new mold unit 1 f is connected to the other end B of the connection mold 10. The resin solution annular slit head 11 continuously discharges the resin solution 4 in the integrated supply tank 12 while controlling the resin solution 4 from the outside to the outer peripheral surface of the connection mold 10 at a predetermined speed. On the other hand, the connecting mold 10 moves upward in FIG. 4 at a predetermined speed. As a result, the resin solution 4 is continuously applied across a plurality of mold units. In FIG. 4, the connecting mold 10 is moved and the annular slit head 11 is fixed. However, there is no particular limitation as long as the annular slit head 11 can move relative to the connecting mold 10. It may move in the opposite direction, or the connecting mold 10 may be fixed and the annular slit head 11 may move.

A specific example of separating / connecting the mold unit while continuously applying is shown below.
First, the connecting mold 10 is moved upward as shown in FIG. 4 and continuous coating by the annular slit head 11 is started. As shown in FIG. 4, the application of the first mold unit 1a is completed, and the application is continuously applied to the second mold unit 1b and the third mold unit 1c. Then, when the joint between the third mold unit 1c and the fourth mold unit 1d connected to the annular slit head 11 is reached, the first mold unit 1a is separated upward. At the same time, a new mold unit 1f (sixth) is connected under the lowermost fifth mold unit 1e. Thereafter, each time the annular slit head 11 reaches the joint of the next mold unit (for example, the joint between the mold units 1d and 1e), the uppermost mold unit (for example, the mold unit 1b) is moved. By repeating the cycle of separating and connecting a new mold unit (not shown) under the lowermost mold unit (for example, the mold unit 1f), application to a plurality of mold units is continued. Done.

  In the present invention, before the mold unit is separated, pressing and regulation by the regulating member are performed. Hereinafter, the mold unit at the one end side end portion that has been applied by continuous application from one end side of the connected mold, and the mold unit to be separated first is referred to as “mold unit p” (in FIG. 4). 1a), the mold unit adjacent to the mold unit p is referred to as “mold unit q” (1b in FIG. 4).

  When pressing and regulating by the regulating member, as shown in FIG. 5A, the molds are applied to the resin coating film 4 on the surfaces of the mold unit p (1a) and the mold unit q (1b). The restriction member 20 is pressed by the joint 16 of the unit, and as shown in FIG. 5 (B), the end 41a on the mold unit q side in the resin coating 4a on the surface of the mold unit p (1a), and the mold The end 41b on the mold unit p side of the resin coating 4b on the surface of the unit q (1b) is regulated. Specifically, as shown in FIG. 5 (B), the resin coating 4 is pushed on the mold surface by pressing the regulating member 20, and the raised portions 42a are formed on both sides of the regulating member 20 in a cross section passing through the mold axis. , 42b is formed, and the shape of the end portions 41a, 41b is controlled by regulating the raised portion. The raised portions 42a and 42b at the ends 41a and 41b may have a free surface as shown in FIG. 5B or may be regulated by the regulating member 20. Such end portions 41 a and 41 b correspond to the reinforcing portion 102 in the belt 100 described above. FIG. 5 (A) is an enlarged schematic view of the mold unit connecting portion where the application of the resin solution is completed, and FIG. 5 (B) applies a regulating member to the resin coating film shown in FIG. 5 (A). It is an enlarged schematic diagram. The joint is a joint between the mold units on the resin solution application surface.

  After performing pressing and regulation by such a regulating member, the mold unit p is separated. At that time, as shown in FIG. 5C, the regulating member 20 is divided in the mold axial direction, and thereafter, the resin coating film 4a on the surface of the mold unit p (1a) and the mold unit q ( 1b) It is preferable to continue regulation of the end portions (41a, 41b) of the resin coating film 4b on the surface. Reference numerals 20a and 20b are divided restriction members, and such restriction by the division restriction members 20a and 20b is normally continued until the drying process described later is completed. FIG. 5C is an enlarged schematic view of the mold unit p cut off after applying the regulating member. In the present invention, after pressing and regulating by the regulating member, it is not necessary to divide the regulating member 20 and continue to regulate the end portion. The unit p may be separated.

  As shown in FIG. 6 (A), the restricting member 20 has the restricting portions 202a and 202b for restricting the displacement portions 201a and 201b and the end portions 41a and 42b for pushing the resin coating film when pressed against the resin coating film. The shape is not particularly limited. It is preferable that the regulating member 20 can continue to regulate the end portions 41a and 41b by dividing itself when the mold unit p is separated. In FIG. 6A, the displacement portions 201a and 201b are provided with positioning portions 203a and 203b, respectively, and when the resin coating film is pushed away by the displacement portions, the positioning portions 203a and 203b are connected to the joints between the mold units. By inserting, the position accuracy of the end can be improved, but in the present invention, the regulating member 20 does not necessarily have to have the positioning portions 203a and 203b. For example, the restricting member 20 shown in FIG. 6A specifically breaks up and down along the surface of the upper and lower mold units from the positioning portions 203a and 203b, and restricts the end position of the resin coating film. Stands vertically from the surface of the mold unit at the position (Y in FIG. 6 (A)), and then again at the position (T in FIG. 6 (A)) for regulating the thickness of the resin coating film end portions 41a and 41b. It has a shape that folds up and down in parallel with the surface of the mold unit, and further folds vertically from the surface of the mold unit at an arbitrary length. FIG. 6A shows the cross-sectional shape of the regulating member 20, and more specifically, the cross-section of the regulating member in the cross section passing through the mold axis when the resin coating on the mold surface is regulated using the regulating member. FIG. The regulating member actually has a three-dimensional shape that circulates around the mold with such a cross-sectional shape, and is divided into two or more in the circumferential direction. FIG. 6 (B) shows a sketch of one division regulating member when the regulating member shown in FIG. 6 (A) is equally divided in the mold axial direction and the circumferential direction and consists of four divided parts.

  The specific dimension of the regulating member 20 is not particularly limited as long as the end portion can be regulated. For example, the length of the displacement portion that regulates the end position of the resin coating film (Y in FIG. 6A) is: When the average thickness of the belt other than the end is t (μm), it is 2 × t or more, particularly 2 × t or more and 10 × t or less, preferably 4 × t or more and 6 × t or less. Further, for example, the height of the restricting portion that regulates the end thickness of the resin coating (T in FIG. 6A) is 1.5 × t or more, particularly 1.5 × t or more, for t similar to the above. 5 × t or less, preferably 2 × t or more and 3 × t or less.

  The constituent material of the regulating member is not particularly limited, and examples thereof include metals such as iron, stainless steel, aluminum, and aluminum alloys, and heat resistant resins such as polyimide and polyamideimide. In order to improve the releasability of the regulating member, it is preferable to apply a silicone resin layer or a fluororesin layer to the member surface.

  In the present invention, after applying the resin solution and before pressing or regulating the resin coating film with the regulating member, the resin coating film on the surface of the mold unit p and the resin coating film on the surface of the mold unit q It is preferable to cut at the joint of the mold unit. After the resin coating is cut at the joint between the mold unit p and the mold unit q, by pressing and regulating with the regulation member at the joint, the gap between the displacement part of the regulation member and the mold surface It is possible to suppress the resin coating film from remaining on the surface.

  The cutting means is not particularly limited, and examples thereof include discharging air, using a blade, a laser, and the like, but preferably discharging air. When contact type cutting means such as a blade is used, when the blade is moved away from the resin coating after cutting, the resin coating that is a viscous fluid is pulled while being attached to the blade. Also, if you use a cutting means with a thin cut width, such as a laser, even if it is cut while applying the laser, the resin film on the upper surface of the cut hangs as soon as it is turned off, It will be connected again. In contrast to these cutting means, cutting means by air discharge is effective because it is non-contact and has a sufficient cut width.

  In the case of cutting by air discharge, in detail, as shown in FIG. 7A, by discharging air 13 onto the resin coating film 4, as shown in FIG. 7C, the resin coating film 4 Is pushed to both sides of the air discharge line 14 on the mold surface. Thereby, the resin coating film 4 is cut and divided. FIG. 7 (A) is an enlarged schematic view of the mold unit connecting portion after application of the resin solution is completed, and FIG. 7 (C) is an enlarged view of the resin coating film shown in FIG. 7 (A) cut by air. It is a schematic diagram. In FIG. 7A and FIG. 7C, the gap 15 is formed between the mold unit 1a and the mold unit 1b, but it may be omitted. In FIG. 7A, the air 13 is discharged from the outside of the mold unit to the resin coating film 4. If there is a gap 15 between the mold unit 1a and the mold unit 1b, Without being restricted, as shown in FIG. 7B, the air 13 may be discharged from the inside of the mold unit to the resin coating film 4 through the gap 15. An air discharge line is a line which shows the discharge direction of air.

  The discharge of air is achieved by an annular slit head for air (not shown), for example. The annular slit head for air is located outside or inside the connected mold with a predetermined clearance from the resin solution application surface of the mold, and has a uniform pressure over the entire circumference of the mold from the annular slit. To blow out compressed air. The air pressure is not particularly limited as long as it can push the resin coating film and achieve separation and division of the resin coating film.

  Air is discharged with the target of the joint between the mold unit p and the mold unit q. Therefore, the resin coatings 4a and 4b pushed to the both sides of the air ejection line 14 on the mold surface by air ejection are divided at a substantially constant width across the joint 16 as shown in FIG. 7C. .

  The operation of separating the mold unit p and connecting the new mold unit (for example, 1f in FIG. 4) is performed by the resin solution annular slit head for applying the resin solution at the joint position of another mold unit, for example, FIG. Is performed at the joint position between the mold units 1c and 1d. Even if a series of mold units are disconnected / connected, even if there is an adverse effect such as a film thickness disturbance on the resin solution coating operation due to vibrations, etc., this control is to minimize such an adverse effect. . Even if an adverse effect such as a disturbance in film thickness occurs at the joint of the mold unit in the resin coating film, an end (reinforcing part) will be formed in the future at the joint, so the influence is small.

  The resin solution used in the present invention is obtained by dissolving a resin capable of forming the constituent material of the belt base material and the reinforcing portion in an organic solvent. Examples of such a resin include an uncured liquid thermosetting resin, an uncured solid thermosetting resin, and a thermoplastic resin. The organic solvent is not particularly limited as long as it can dissolve the resin, and examples thereof include an organic solvent described later. Note that when a liquid resin is used, it is not always necessary to use an organic solvent.

  In this method, for example, when a polyimide resin-made annular seamless belt is produced, a polyimide precursor solution is used as the resin solution. As a polyimide precursor, a so-called polyamic acid, for example, a precursor comprising 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA), pyromellitic dianhydride A precursor composed of (PMDA) and 4,4′-diaminophenyl ether (ODA) is used.

  For example, when manufacturing the annular seamless belt made from a polyamideimide resin, a polyamideimide precursor solution is used as the resin solution. As the polyamideimide precursor, for example, a precursor composed of an amide group-containing aromatic diamine and PMDA, a precursor composed of an aromatic diamine or a derivative thereof and trimellitic anhydride (TMA), or the like is used.

Hereinafter, as a particularly preferred embodiment, a method for producing an annular seamless belt made of polyimide resin will be described in detail.
The manufacturing method of the polyimide resin annular seamless belt of the present invention includes the following steps;
While continuously applying the resin solution from one end side to the connected mold, a mold unit that has been applied at the outermost end of the one end side among the mold units constituting the connected mold. A resin coating film forming step in which a cycle of detaching and connecting a new mold unit to the other end side of the connected mold is repeated, and the mold unit p and the mold are separated before the mold unit is separated. The resin film on the surface of the mold unit q adjacent to the unit is pressed against the resin film on the mold unit q side of the resin film on the surface of the mold unit p by pressing the regulating member at the joint of the mold units. A step of regulating the end and the end on the mold unit p side of the resin coating on the surface of the mold unit q;
A drying step of heating and drying the resin coating on the surface of the separated mold unit;
A baking step of heating and baking the dried resin coating; and a demolding step of peeling the fired resin coating from the mold unit.

(Resin coating film forming process)
This process is the same as the resin coating film forming process described above unless otherwise specified.
The resin solution is a polyimide precursor solution. The polyimide precursors described above can be used, and two or more kinds may be mixed and used.

  The organic solvent is not particularly limited as long as it can dissolve the polyimide precursor, and examples thereof include N-methylpyrrolidone, N, N-dimethylacetamide, acetamide, N, N-dimethylformamide and the like. The concentration, viscosity, and the like of the polyimide precursor in the resin solution are appropriately selected according to the coating method, the desired thickness of the belt, and the like.

  When the obtained molded body is imparted with a conductive function such as a fixing belt, an intermediate transfer belt, or a contact charging belt, an additive of a conductive substance can be dispersed in the resin solution.

(Drying process)
In this step, the resin coating film is heated and dried.
Specifically, for the purpose of removing the solvent remaining excessively in the resin coating film, the film is heated and dried to such an extent that the coating film does not deform even when left standing. The drying conditions are preferably 80 to 200 ° C. and 30 to 60 minutes. At that time, the higher the temperature, the shorter the heating time. In addition to heating, it is also effective to apply wind. Further, if far infrared heating or halogen heating is used, the solvent can be removed more efficiently. Heating may be increased stepwise or at a constant rate over time. If the solvent is removed too much from the resin coating film, the coating film does not yet retain the strength as a belt, and there is a risk of cracking. For this reason, it is preferable to leave the solvent appropriately. Specifically, it is preferable to leave the solvent in the resin coating film at a rate of 15 to 50% by mass, particularly 35 to 50% by mass.

(Baking process)
In this step, the dried resin coating is heated and fired.
Specifically, the polyimide resin film can be formed by heating and reacting the resin coating film at 300 to 450 ° C., preferably around 350 ° C. for 20 to 60 minutes. During the heating reaction, if the organic solvent remains in the coating film, the polyimide resin film may swell, so it is preferable to completely remove the residual solvent before reaching the final temperature of heating, Specifically, before heating, the solvent is removed by heating and drying at a temperature of 200 to 250 ° C. for 10 to 30 minutes, and then the temperature is gradually increased stepwise or at a constant rate. It is preferable to form a polyimide resin film. At this time, if far infrared heating or halogen heating is used in combination, the removal of the residual solvent and the imidization reaction can be performed efficiently.

(Demolding process)
In this step, the fired resin coating film (polyimide resin film) is peeled off from the mold unit and demolded.
The method for peeling the resin coating film from the mold unit is not particularly limited. For example, the coating film can be expanded and peeled by injecting pressurized air into the gap between the mold unit and the coating film. The pressure of the pressurized air may be about several atmospheres obtained with a general air compressor. The injected pressurized air leaks to some extent from the end of the film, but not all of it leaks, so the film will swell somewhat due to air pressure. Therefore, the formed resin coating film can be easily extracted from the mold unit.

  The extracted resin coating film has a width equivalent to a predetermined width of one annular seamless belt, and the reinforcing portions are integrally provided at both ends in the width direction, so that it has excellent durability. It can be used as it is as an annular seamless belt.

<Example 1>
(Manufacture of mold unit A)
An aluminum cylindrical mold unit having an inner diameter of 26 mm, an outer diameter of 30 mm, and a length of 300 mm was manufactured by a casting method, and a convex portion and a concave portion as shown in FIG. 2 were provided by cutting. The step in the axial direction of the convex part and the concave part was 5 mm.
A silicone resin film (film thickness: about 1 μm) is formed as a release layer by applying a silicone release agent (trade name: KS700, Shin-Etsu Chemical Co., Ltd.) on the outer peripheral surface of the mold unit. Used as unit A.

(Manufacture of linked molds)
Five mold units A were connected to produce a connected mold.

(Resin coating film forming process)
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) are reacted in N, N-dimethylacetamide to obtain a 22% by weight polyimide precursor. Body solution A was prepared. Carbon black (trade name: Special Black 4, manufactured by Degussa Huls) was mixed with the precursor solution A in a solid mass ratio of 23%, and then dispersed by a jet mill to obtain a resin solution A.
As shown in FIG. 4, the resin solution A is continuously applied from one end side to the connected mold by the annular slit head for the resin solution, and among the mold units constituting the connected mold. The cycle in which the mold unit on which application was completed at the one end side end was cut off and a new mold unit was connected to the other end side of the connection mold was repeated.

Immediately before separating the mold unit, as shown in FIGS. 5 (A) and 5 (B), those molds are applied to the resin coating film 4 on the surfaces of the mold unit 1a and the mold unit 1b. The regulating member 20 was pressed at the joint between the units to regulate the end 41a of the resin coating 4a on the mold unit 1a surface and the end 41b of the resin coating 4b on the mold unit 1b surface. The used regulating member had the shape shown in FIG. 6 and had dimensions of Y = 2.0 mm and T = 1.0 mm.
When the mold unit 1a is separated, as shown in FIG. 5C, the regulating member is divided so that the end 41a of the resin coating 4a on the surface of the mold unit 1a and the resin coating 4b on the surface of the mold unit 1b The end 41b was continuously regulated. Such regulation was performed until the drying process described later was completed.
The separation of the mold unit 1a and the connection of the new mold unit were performed when the resin solution annular slit head 11 was at the joint position between the mold unit 1c and the mold unit 1d as shown in FIG.
A resin coating film having a thickness of about 500 μm was formed on the surface of any of the separated mold units at portions other than the end portions. The edge part of the resin coating film had a thickness of about 1000 μm.

The following steps were performed for each separated mold unit.
(Drying process)
Next, the mold unit was placed horizontally and rotated at 20 rpm, followed by drying at room temperature for 5 minutes, followed by heat drying at 80 ° C. for 20 minutes and at 100 ° C. for 1 hour. Thereby, a resin coating film having a thickness of about 150 μm was obtained.

(Baking process)
Next, the mold unit was once cooled to room temperature. Thereafter, the mold unit was set up vertically and reacted by heating at 200 ° C. for 30 minutes and at 300 ° C. for 30 minutes to form a polyimide resin film.

(Demolding process)
After cooling to room temperature, when pressurized air with a pressure of 0.5 MPa was injected into the gap between the mold unit and the polyimide resin film, the polyimide resin film expanded and could be easily removed. The obtained belt had dimensions that could be used as an electrophotographic transfer belt as it was. The belt substrate 101 had an average thickness of 100 μm, and the reinforcing portion 102 had an average thickness of 200 μm.

(Evaluation)
A predetermined cycle of the resin coating film forming step was repeated 100 times to produce 100 belts. No belt breakage occurred. Further, since the resin solution was continuously applied, the productivity was excellent.
As a result of measuring the thickness of any 10 points in the belt base part for each of the 10 belts, the difference between the maximum value and the minimum value was 14 μm or less for all the belts, and the film thickness was excellent. .
Even when the obtained belt was mounted on an image forming apparatus as an intermediate transfer belt and continuously driven for 30 days, no cracks occurred on the belt end face.

<Example 2>
After applying the resin solution and before pressing and regulating the resin coating film with the regulating member, as shown in FIG. A belt was produced in the same manner as in Example 1 except that the resin coating film was cut around the mold as shown in FIG. The obtained belt had dimensions that could be used as an electrophotographic transfer belt as it was. The belt substrate 101 had an average thickness of 100 μm, and the reinforcing portion 102 had an average thickness of 200 μm.

(Evaluation)
A predetermined cycle of the resin coating film forming step was repeated 100 times to produce 100 belts. No belt breakage occurred. Further, since the resin solution was continuously applied, the productivity was excellent.
As a result of measuring the thickness of any 10 points in the belt base part for each of the 10 belts, the difference between the maximum value and the minimum value was 14 μm or less for all the belts, and the film thickness was excellent. .
Even when the obtained belt was mounted on an image forming apparatus as an intermediate transfer belt and continuously driven for 30 days, no cracks occurred on the belt end face.

  The belt of the present invention is useful as an intermediate belt, a contact charging belt, and a fixing belt of an image forming apparatus, particularly an electrophotographic image forming apparatus.

It is a schematic sketch of one embodiment of the annular seamless belt of the present invention. It is a schematic block diagram which shows one Embodiment of the die unit which comprises the connection type metal mold | die used by this invention. It is a schematic block diagram which shows one Embodiment of the connection type metal mold | die used by this invention. It is a schematic diagram for demonstrating an example of the resin coating film formation process in the manufacturing method of the cyclic | annular seamless belt of this invention. (A) is an expansion schematic diagram of an example of the die unit connection part in which application | coating of the resin solution was completed, (B) is an expansion schematic diagram of the place which applied the control member with respect to the resin coating film shown to (A). It is a figure and (C) is an enlarged schematic diagram of the place which cut | disconnects the die unit p after applying a control member. (A) shows the schematic cross-sectional shape of a control member, (B) shows the sketch of the division | segmentation control member which comprises the control member shown to (A). (A) And (B) is an expansion schematic diagram of an example of the die unit connection part by which application | coating of the resin solution was completed, (C) cut the resin coating film shown to (A) and (B) with air It is an enlarged schematic diagram.

Explanation of symbols

  1: 1a: 1b: 1c: 1d: 1e: 1f: mold unit, 2: convex part, 3: concave part, 4: 4a: 4b: resin coating film (resin solution), 10: coupled mold, 11: 21: annular slit head, 12:22: supply tank, 13: air, 14: air discharge line, 15: gap, 16: joint, 20: regulating member, 41a: 41b: end, 42a: 42b: raised part, 100: annular seamless belt, 101: belt base material, 102: reinforcing portion, 201a: 201b: displacement portion, 202a: 202b: regulating portion, 203a: 203b: positioning portion.

Claims (5)

The connected mold is constructed by continuously applying a resin solution from one end to the surface of a connected mold formed by connecting two or more mold units that can be connected / disconnected in the axial direction. Of an annular seamless belt that repeats a cycle in which a mold unit that has been applied at the end of one end side of the mold unit to be applied is cut off and a new mold unit is connected to the other end of the connected mold A method,
Before the mold unit is separated, the regulating member is pressed against the resin coating on the surface of the mold unit p to be separated and the mold unit q adjacent to the mold unit at the joint of the mold units. And restricting the mold unit q side end of the resin coating on the mold unit p surface and the mold unit p side end of the resin coating on the mold unit q surface ,
An annular seamless characterized in that the resin coating is pushed on the mold surface by pressing the regulating member to form the raised portions on both sides of the regulating member while regulating the raised portions to form the end portions. A method for manufacturing a belt. The annular seamless belt according to claim 1 , wherein the resin coating film on the surface of the mold unit p and the resin coating film on the surface of the mold unit q are cut at a joint between the mold units before pressing the regulating member. Production method. The manufacturing method of the cyclic | annular seamless belt of Claim 2 which achieves cutting of a resin coating film by discharge of air. When disconnecting the mold unit p, by dividing the the regulating member, then, according to claim 1 to 3, to continue the ends regulations in the resin coating film of the resin coating film and the mold unit q surface of the mold unit p surfaces The manufacturing method of the cyclic | annular seamless belt in any one of. The method for producing an annular seamless belt according to any one of claims 1 to 4 , wherein the resin solution is a polyimide precursor solution.

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