JP5110214B1 - Drying apparatus and endless belt manufacturing method - Google Patents

Abstract

An object of the present invention is to suppress uneven drying of a solution applied to a core.
Rotating means for rotating a cylindrical or columnar core having a solution applied to an outer peripheral surface about an axis, and a length in a longitudinal direction along the axial direction of the core is the outer circumference of the core A wind generating means that has a blowing port that is equal to or longer than the length of the application region of the solution on the surface and whose length in the short direction is smaller than the diameter of the core, and blows the solution from the blowing port; The length in the longitudinal direction along the axial direction of the core is equal to or longer than the length of the application region of the solution on the outer peripheral surface of the core, and the length in the short direction is larger than the diameter of the core. A drying device having a small suction port, and disposed at a position opposite to the wind generating unit with respect to the rotation center of the core body, and sucking the wind that has hit the solution through the suction port. .
[Selection] Figure 4

Description

  The present invention relates to a drying apparatus and a method for manufacturing an endless belt.

  Patent Document 1 discloses that a core having a coating film formed on its surface by applying a film-forming resin solution is placed in a drying furnace and heated to dry the coating film to form a resin film. And a heating step in which the core body on which the resin film is formed is placed in a heating furnace and heated to fire the resin film. In the heating step, exhaust gas exhausted from the heating furnace is removed. An endless belt manufacturing method is disclosed, wherein the endless belt is supplied to the drying furnace.

JP 2007-216510 A

  This invention makes it a subject to suppress the drying nonuniformity of the solution apply | coated to the core.

  According to the first aspect of the present invention, there is provided a rotating means for rotating a cylindrical or columnar core whose solution is applied to the outer peripheral surface about an axis, and a length in a longitudinal direction along the axial direction of the core is the core. A wind that has an air blowing port that is not less than the length of the application area of the solution on the outer peripheral surface of the body and that has a length in the short direction smaller than the diameter of the core body, and blows air to the solution from the air blowing port. The length in the longitudinal direction along the axial direction of the core is greater than or equal to the length of the application area of the solution on the outer peripheral surface of the core, and the length in the short direction of the core A suction means having a suction port smaller than the diameter, disposed at a position opposite to the wind generating means with respect to the center of rotation of the core body, and sucking the wind hitting the solution through the suction port; It is a drying device provided.

  According to a second aspect of the present invention, there is provided a rotating means for rotating a cylindrical or columnar core whose solution is applied to the outer peripheral surface about an axis, and a length in a longitudinal direction along the axial direction of the core is the core. A wind that has an air blowing port that is not less than the length of the application area of the solution on the outer peripheral surface of the body and that has a length in the short direction smaller than the diameter of the core body, and blows air to the solution from the air blowing port. The length in the longitudinal direction along the axial direction of the core is greater than or equal to the length of the application area of the solution on the outer peripheral surface of the core, and the length in the short direction of the core A plurality of suction ports having a suction port smaller than the diameter, arranged in the circumferential direction of the core body, and a suction unit that sucks the wind hitting the solution from both sides of the wind generation unit through the suction port; Device.

  The invention of claim 3 further includes infrared generation means arranged along the axial direction of the core, and control means for controlling the wind generation means and the infrared generation means, the control means comprising: The infrared ray generation means is stopped until the constant rate drying period of the solution, the solution is dried by the wind generation means, and the wind generation means is stopped during the reduced rate drying period of the solution, and the infrared ray generation means The drying apparatus according to claim 1 or 2, wherein the solution is dried.

  The invention according to claim 4 is an application step of applying a solution to the outer peripheral surface of a cylindrical or columnar core, and the solution is dried by the drying apparatus according to any one of claims 1 to 3. And a drying step of forming a film on the outer peripheral surface of the core body.

  According to the structure of Claim 1 of this invention, compared with the case where the suction device in this structure is not provided, the drying nonuniformity of the solution apply | coated to the core can be suppressed.

  According to the structure of Claim 2 of this invention, compared with the case where the suction device in this structure is not provided, the drying nonuniformity of the solution apply | coated to the core can be suppressed.

  According to the structure of Claim 3 of this invention, compared with the structure which is not provided with this structure, drying time can be shortened.

  According to the manufacturing method of claim 4 of the present invention, an endless belt having a small variation in surface resistivity can be obtained as compared with the case where the drying step in the manufacturing method is not provided.

It is a figure which shows the process order of the manufacturing method of the endless belt which concerns on 1st Embodiment. It is the schematic which shows the structure of the coating device used for the coating process (spiral coating method) which concerns on 1st Embodiment. It is the schematic which shows the structure of the drying apparatus used for the drying process which concerns on 1st Embodiment. It is the elements on larger scale which expanded the drying apparatus shown in FIG. 3 partially. It is the perspective view which looked up the nozzle of the air blower in the drying apparatus shown in FIG. 3 from the air outlet side. It is the perspective view which looked up the nozzle of the suction device in the drying apparatus shown in FIG. 3 from the suction port side. It is the schematic which shows the structure of the heating apparatus used for the baking process which concerns on 1st Embodiment. It is the schematic which shows the structure of the drying apparatus which concerns on a modification. It is the schematic which shows the structure of the drying apparatus which concerns on a modification. It is the schematic which shows the structure of the drying apparatus used for the drying process which concerns on 2nd Embodiment. It is a graph which shows an example of the mode of the reduction state of the solvent in the drying process concerning a 2nd embodiment.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

[First Embodiment]
(Method for manufacturing intermediate transfer belt)
First, as an example of a method for manufacturing an endless belt, a method for manufacturing an intermediate transfer belt used in an electrophotographic image forming apparatus will be described. FIG. 1 is a diagram illustrating a process sequence of a method for manufacturing an intermediate transfer belt. The endless belt is not limited to the intermediate transfer belt, and may be, for example, a sheet conveying belt that conveys a sheet, and may be an endless belt.

  As shown in FIG. 1, the method for manufacturing the intermediate transfer belt includes a coating process, a drying process, a baking process, and a removing process. These steps are performed in the order of the coating step, the drying step, the firing step, and the removal step. Hereinafter, each step will be described.

(Coating process)
In this application process, a resin solution containing a resin as an example of a solution as a main component is applied to the outer peripheral surface of a cylindrical or columnar core. As a specific coating method in this coating process, for example, a spiral coating method in which a resin solution is spirally coated on the outer peripheral surface of the core body is used. The application method for applying the resin solution to the core is not limited to the spiral application method, and may be another application method.

  In the spiral coating method, for example, as shown in FIG. 2, the resin solution 50 is discharged from the flow-down device 52 while rotating the cylindrical or columnar core 38 around the axis with the axial direction horizontal. It adheres to the outer peripheral surface of the core body 38. The resin solution 50 is supplied from a tank 54 that stores the resin solution 50 to a flow-down device 52 through a supply pipe 58 by a pump 56. The resin solution 50 attached to the outer peripheral surface of the core body 38 is smoothed by the spatula 60. The core body 38 rotates in the arrow B direction around the axis in a state where the axial direction is horizontal by the rotating device 43 (see FIG. 3).

  The flow-down device 52 and the spatula 60 are supported so as to be movable in the axial direction of the core body 38, and the flow-down device 52 and the spatula 60 are in the state where the core body 38 is rotated at a preset rotational speed. By discharging the resin solution 50 while moving in the axial direction (direction of arrow C) of the body 38, the resin solution 50 is spirally applied to the outer peripheral surface of the core body 38 and smoothed with the spatula 60, A coating film 62 that is not present is formed. The film thickness is set as necessary in the range of 50 μm or more and 150 μm or less, for example, in a state after completion.

(Resin solution)
The resin solution applied to the core body 38 will be described.
For the resin constituting the intermediate transfer belt, polyimide resin (hereinafter referred to as PI), polyamideimide resin (hereinafter referred to as PAI), etc. are used in terms of strength, dimensional stability, heat resistance and the like. It is not limited to. As PI or PAI, various known ones can be used. For example, in the case of PI, a precursor solution thereof is used.

  The PI precursor solution can be obtained by reacting a tetracarboxylic dianhydride and a diamine component in a solvent. Although the kind in particular of each component is not restrict | limited, What is obtained by making an aromatic tetracarboxylic dianhydride and an aromatic diamine component react is preferable from the point of film strength.

  Typical examples of the aromatic tetracarboxylic acid include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and 3,3 ′, 4,4′-benzophenone. Tetracarboxylic dianhydride, 2,3,4,4′-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetra Examples thereof include carboxylic dianhydrides, 2,2-bis (3,4-dicarboxyphenyl) ether dianhydrides, tetracarboxylic acid esters thereof, and mixtures of the above tetracarboxylic acids.

  Examples of the aromatic diamine component include paraphenylenediamine, metaphenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminophenylmethane, benzidine, 3,3′-dimethoxybenzidine, and 4,4′-diaminodiphenyl. Examples include propane and 2,2-bis [4- (4-aminophenoxy) phenyl] propane.

  On the other hand, PAI is an acid anhydride such as trimellitic anhydride, ethylene glycol bisanhydro trimellitate, propylene glycol bisanhydro trimellitate, pyromellitic acid anhydride, benzophenone tetracarboxylic acid anhydride, 3, 3 It can be obtained by combining the above diamine with ', 4,4'-biphenyltetracarboxylic anhydride and the like and subjecting it to a polycondensation reaction in an equimolar amount. Since PAI has an amide group, it is easily dissolved in a solvent even if the imidization reaction proceeds, so that 100% imidized is preferable.

  As the solvent contained in the resin solution, an aprotic polar solvent such as N-methylpyrrolidone, N, N-dimethylacetamide, or acetamide is used. The concentration and viscosity of the solution are not limited. For example, the solid content concentration of the solution is 10% by mass to 40% by mass, and the viscosity of the liquid is 1 Pa · s to 100 Pa · s.

  Conductive particles may be added to the resin solution as necessary. Examples of the conductive particles dispersed in the resin solution include carbon-based materials such as carbon black, carbon fiber, carbon nanotube, and graphite, metals or alloys such as copper, silver, and aluminum, tin oxide, indium oxide, and antimony oxide. Examples thereof include conductive metal oxides and whiskers such as potassium titanate. Among these, carbon black is particularly preferable from the viewpoints of dispersion stability in liquid, expression of semiconductivity, price, and the like.

  As a method for dispersing the conductive particles, a known method such as a ball mill, a sand mill (bead mill), a jet mill (counter collision type disperser), or the like can be used. As a dispersion aid, a surfactant, a leveling agent, or the like may be added. The dispersion concentration of the conductive particles is preferably 10 parts or more and 40 parts or less, and particularly preferably 15 parts or more and 35 parts or less with respect to 100 parts (parts by mass) of the resin component.

(Core 38)
The core body 38 to which the resin solution 50 is applied will be described.
The core body 38 is formed in a cylindrical shape or a columnar shape. Further, as the core body 38, a metal such as aluminum, nickel alloy, stainless steel or the like is used.

  Furthermore, in the baking process described later, when the film formed by the resin solution 50 formed on the outer peripheral surface of the core body 38 is heated, the film is formed by the influence of a double product such as a solvent or water remaining in the film. From the viewpoint of suppressing the occurrence of swelling, the outer peripheral surface of the core body 38 is desirably roughened.

  When the outer peripheral surface of the core body 38 is roughened, when the film formed on the core body 38 is heated, residual solvent or water vapor generated from the film is slightly between the core body 38 and the film. Is released through a gap. For this reason, it is suppressed that a swelling arises in a film. As a method for roughening the outer peripheral surface of the core body 38, there are methods such as blasting, cutting, sandpapering and the like.

  The length of the core body 38 in the axial direction needs to be equal to or longer than the width (axial length) of the intermediate transfer belt to be manufactured. It is desirable that the width is 3% or more and 40% or less longer than the width of the target intermediate transfer belt. The circumferential length of the core body 38 is equal to or slightly larger than the length of the intermediate transfer belt to be manufactured. The diameter (outer diameter) of the core body 38 is determined by the circumferential length of the core body 38.

  A cylindrical (annular) application region 38 </ b> A to which the resin solution 50 is applied is set on the outer peripheral surface of the core body 38. The axial length of the application region 38A is equal to or greater than the width of the intermediate transfer belt to be manufactured (axial length) and equal to or smaller than the axial length of the core body 38.

  Before applying the resin solution 50 to the outer peripheral surface of the core body 38, a masking member may be wound around the outer peripheral surfaces of both ends of the core body 38 as a peeling auxiliary member. As the masking member, a resin film such as polyester or polypropylene, or an adhesive tape based on a paper material such as crepe paper or flat paper can be used. The width of the adhesive tape is preferably about 10 mm to 25 mm. The pressure-sensitive adhesive material of the pressure-sensitive adhesive tape is preferably an acrylic pressure-sensitive adhesive material, and in particular, the pressure-sensitive adhesive material that does not remain on the outer peripheral surface of the core body 38 when peeled off is suitable.

  When the masking member is attached to the outer peripheral surfaces of both ends of the core body 38 before the resin solution 50 is applied to the outer peripheral surface of the core body 38, the masking member is dried after the resin solution 50 is dried by a drying process described later. It is peeled off. By peeling off the masking member, a gap (gap) is provided between at least a part of the end of the dried coating film 62 and the core. Then, a gas is blown into the gap, and a resin film obtained through a baking process described later is extracted from the core body 38, whereby an intermediate transfer belt is easily and efficiently produced. Moreover, since excessive force is not applied when extracting, the generation | occurrence | production of inferior goods is prevented.

(Drying process)
In the drying process, the resin solution 50 applied to the core body 38 in the application process is dried by the following drying device 10 to form a film on the outer peripheral surface of the core body 38.

  FIG. 3 is a schematic diagram illustrating the configuration of the drying apparatus 10. As shown in FIG. 3, the drying apparatus 10 includes a rotation device 43 as an example of a rotation unit that rotates the core body 38 about an axis, and a resin solution 50 (coating film 62 (FIG. 2) applied to the core body 38. The air blower 12 as an example of the wind generating means for applying the wind to the reference)) and the suction device 30 as an example of the suction means for sucking the wind hitting the resin solution 50 are provided.

  Further, the drying device 10 includes a drying furnace 26 in which the rotating device 43, the blower device 12, and the suction device 30 are accommodated. The drying furnace 26 is provided with a blower 28 that sends hot air into the drying furnace 26. The blower 28 is configured to send hot air from the upper part of the drying furnace 26 into the drying furnace 26 and to discharge and circulate from the lower part. The wind speed of the hot air is slower than the wind speed in the nozzle 16 described later, and is almost negligible on the outer peripheral surface of the core body 38 (the wind speed that does not affect the hot air (wind speed) in the nozzle 16 described later). Specifically, the wind speed of the hot air from the upper part of the drying furnace 26 is set in the range of 0.5 m / s or more and 2 m / s or less, for example.

  The set temperature in the drying furnace 26 may be the same as or different from the temperature of the air blown from the nozzle 16. In the drying apparatus 10, the core body 38 is accommodated in the drying furnace 26 and the resin solution 50 on the core body 38 is dried, so that the temperature of the air around the core body 38 is maintained high, and the entire resin solution 50 is Drying is promoted.

  The rotating device 43 includes, for example, a support portion 44 that rotatably supports both axial ends of the core body 38, a drive portion 46 that rotationally drives the core body 38 that is rotatably supported by the support portion 44, and have. In the rotating device 43, the core body 38 is rotated so that the peripheral speed of the core body 38 is in a range of 0.05 m / s to 5 m / s, for example.

  As shown in FIG. 4, the blower 12 includes a nozzle 16 having a slit-like blower opening 14 having a length in the axial direction of the core body 38, and a blower 18 that sends air to the nozzle 16. Yes. Note that the air blowing unit 18 may include a heating unit (not shown) for heating air, and send air (hot air) heated by the heating unit to the nozzle 16.

  As shown in FIG. 5, one end in the longitudinal direction of the nozzle 16 is connected to the blower 18 through the blower pipe 20, and the wind from the blower 18 passes through the blower 20 from the inlet 22 of the nozzle 16 to the nozzle 16. 16 is configured to flow into the interior. In addition, the connection position with respect to the nozzle 16 of the air pipe 20 is not restricted to the longitudinal direction one end part of the nozzle 16, the longitudinal direction both ends part of the nozzle 16, or the part on the opposite side (left side in FIG. 4) in the nozzle 16 It may be.

  A cavity 24 is formed inside the nozzle 16. By this cavity 24, the air pressure inside the nozzle 16 is made uniform, and the wind speed of the wind coming out from the air blowing port 14 is made uniform in the longitudinal direction of the air blowing port 14. In addition, in order to further improve the uniformity of the air pressure in the cavity 24, a member having air resistance such as a perforated plate may be interposed between the cavity 24 and the air blowing port 14.

  The longitudinal length L (see FIG. 5) along the axial direction of the core body 38 in the air blowing port 14 is set to be equal to or longer than the axial length of the application region 38A (see FIG. 2) in the core body 38. In the present embodiment, the length L is not less than the axial length of the core body 38.

  The width (length in the short direction) W (see FIG. 5) of the air outlet 14 is made smaller than the diameter of the core body 38. The width W of the air blowing port 14 is, for example, in the range of 0.5 mm or more and 2 mm or less. When the width W is less than 0.5 mm, the air volume decreases. When the width W exceeds 2 mm, it is difficult to maintain the axial uniformity of the wind speed. Thus, by making the air outlet 14 into a slit shape and setting the width W within a predetermined range, the air volume (wind speed) blown to the core body 38 is made uniform in the axial direction of the core body 38. .

  As shown in FIG. 4, the air blowing port 14 of the nozzle 16 faces the rotation center C of the core body 38, and the wind from the air blowing port 14 is directed toward the rotation center C of the core body 38. It is set as the structure applied to the outer peripheral surface. That is, the wind from the air blowing port 14 strikes the outer peripheral surface of the core body 38 at a right angle. Note that the wind that hits the outer peripheral surface of the core body 38 at a right angle is divided into two at the outer peripheral surface of the core body 38 and flows to one and the other in the circumferential direction. Furthermore, the wind that has flowed to one and the other in the circumferential direction flows along the circumferential direction of the core body 38 due to the Coanda effect. The wind is merged at a position H on the opposite side of the blower 12 across the rotation center C of the core body 38.

  The wind speed of the wind striking the resin solution 50 on the core 38 is preferably, for example, 5 m / s or more and 50 m / s or less. When the wind speed of the wind is less than 5 m / s, the drying of the resin solution 50 becomes slow. When the wind speed of the wind exceeds 50 m / s, the wind is too strong so that the resin solution 50 has a ripple or a dent. Become.

  The temperature of the wind blown out from the air blowing port 14 of the nozzle 16 is set to a temperature at which the evaporation of the solvent is promoted, and is preferably in the range of 100 ° C. or more and 200 ° C. or less, for example. If the temperature of the wind is low, not only the drying time is extended, but also the film after drying may not have the desired properties. If the temperature of the wind is too high, dents and bubbles appear in the film.

  The suction device 30 is disposed at a position opposite to the blower device 12 with respect to the rotation center C of the core body 38 (on the right side of the dashed line A in FIG. 4). Specifically, the nozzle 16 of the air blower 12 and the suction device 30 (a nozzle 34 described later) are disposed at a position 180 ° away from the central axis of the core body 38. The alternate long and short dash line A is a straight line having an inclination of 90 ° with respect to a line segment connecting the center in the width direction of the blower opening 14 of the nozzle 16 and the rotation center C of the core body 38.

  The suction device 30 includes a nozzle 34 having a slit-like suction port 32 having a length in the axial direction of the core body 38, and a suction unit 36 that sucks from the nozzle 34. One end portion in the longitudinal direction of the nozzle 34 is connected to the suction portion 36 by a suction tube 35, and air is sucked from the suction port 32 of the nozzle 34 through the suction tube 35. Note that the connection position of the suction pipe 35 to the nozzle 34 is not limited to one end in the longitudinal direction of the nozzle 34, both ends in the longitudinal direction of the nozzle 34, and the portion opposite to the suction port 32 (right side in FIG. 4). It may be.

  A cavity (not shown) is also formed inside the nozzle 34, as with the nozzle 16. By this cavity, the air pressure inside the nozzle 34 is made uniform, and the pressure of the air sucked from the suction port 32 is made uniform in the longitudinal direction of the suction port 32.

  A length L (see FIG. 6) in the longitudinal direction of the suction port 32 along the axial direction of the core body 38 is equal to or longer than the axial length of the application region 38A (see FIG. 2) in the core body 38. In the present embodiment, the length L is not less than the axial length of the core body 38.

  The width (length in the short direction) W (see FIG. 6) of the suction port 32 is made smaller than the diameter of the core body 38. The width W of the suction port 32 is, for example, in a range from 0.5 mm to 2 mm. When the width W is less than 0.5 mm, the flow rate to be sucked decreases, and when it exceeds 2 mm, it is difficult to maintain the axial uniformity of the flow rate to be sucked. Thus, by making the suction port 32 into a slit shape and setting the width W to a predetermined range, the suction flow rate is made uniform in the axial direction of the core body 38.

  The suction port 32 of the nozzle 34 faces the rotation center C of the core body 38, and sucks the combined air at a position H on the opposite side of the blower 12 across the rotation center C of the core body 38. Yes.

(Baking process (heating process))
In the firing step, the film formed by drying the resin solution 50 is heated and fired.

  The firing step is required when a material such as a PI precursor that causes a curing reaction by heating is used as the resin. In the firing step, as shown in FIG. 7, the core body 38 is placed in a heating furnace 80 and heated. The heating temperature is preferably 250 ° C. or higher and 450 ° C. or lower, more preferably about 300 ° C. or higher and 350 ° C. or lower. By heating the PI precursor film for 20 to 60 minutes, an imidization reaction occurs, and the PI resin A film is formed. During the heating reaction, it is preferable to heat by gradually increasing the temperature stepwise or at a constant rate before reaching the final heating temperature.

  In addition, when PAI is used as the resin, the baking step is unnecessary, and the PAI resin film is formed only by the drying step of drying the solvent.

  Further, since the support portion 44 provided in the rotating device 43 does not have heat resistance at the high temperature as described above, the core body 38 is preferably removed from the rotating device 43 and placed in the heating furnace 80 in the firing step. Usually, the core body 38 is placed in the heating furnace 80 with the axial direction of the core body 38 along the direction of gravity, that is, vertically. The heating furnace 80 preferably has a configuration in which hot air is blown out from above the vertically standing core body 38 in order to eliminate internal temperature unevenness as much as possible. In order to prevent hot air from directly blowing onto the upper portion of the core body 38, as shown in FIG. The shape of the shielding member 82 is not particularly limited as long as it can cover one end of the core body 38.

(Removal process)
In the removal step, the core body 38 is taken out from the heating furnace 80 after the firing step is finished, and the coating fired in the firing step is removed from the core body 38. Thereby, an intermediate transfer belt is obtained. At that time, it is easy to remove the pressure by blowing the pressurized air into the gap between the end portions of the coating provided by peeling off the masking member to release the adhesion between the coating and the core 38. Since the end portion of the obtained film has defects such as wrinkles and uneven film thickness, unnecessary portions are cut to form an intermediate transfer belt. The intermediate transfer belt may be subjected to drilling or ribbing as necessary.

  When a resin such as PAI that does not require a baking process is used, the core body 38 is taken out from the drying furnace 26 after the drying process, and the film dried in the drying process is removed from the core body 38. Thereby, an intermediate transfer belt is obtained.

  The intermediate transfer belt obtained by the above production method is a transfer body on which an image is transferred from a photoreceptor and the like and transferred to a recording medium, and is used in an image forming apparatus such as an electrophotographic copying machine or a laser printer.

(Operation of the first embodiment)
In the drying process in the manufacturing method of the first embodiment, the wind from the blower opening 14 of the nozzle 16 strikes the outer peripheral surface of the core body 38 toward the rotation center C of the core body 38. The wind hitting the outer peripheral surface of the core body 38 is divided into two on the outer peripheral surface of the core body 38 and flows to one and the other in the circumferential direction. The wind that has flowed to one and the other in the circumferential direction flows along the circumferential direction of the core body 38 due to the Coanda effect, and merges at a position H on the opposite side of the blower 12 across the rotation center C of the core body 38. The wind merged at the opposite position H is sucked from the suction port 32 of the nozzle 34 of the suction device 30.

  Thus, since the suction device 30 sucks the wind to promote the circulation of the wind core body 38 in the circumferential direction, after the wind hits the outer peripheral surface of the core body 38, Difficult to flow in the axial direction. For this reason, compared with the structure of the comparative example which does not attract | suck the wind with the suction device 30, the drying nonuniformity along the axial direction of the core 38 in the resin solution 50 apply | coated to the core 38 is suppressed.

  Further, the wind flows along the circumferential direction of the core body 38 due to the Coanda effect, but gradually flows from the core body 38 to the position H on the opposite side of the blower 12 across the rotation center C of the core body 38. It diffuses away from the outside in the radial direction. In the first embodiment, since the suction device 30 sucks the wind, the circulation of the wind along the circumferential direction of the core body 38 is promoted, so that the air flow along the circumferential direction of the core body 38 without leaving the core body 38. Flowing. For this reason, compared with the structure of the comparative example which does not attract | suck wind with the suction device 30, the drying nonuniformity along the circumferential direction (rotation direction) of the core 38 in the resin solution 50 applied to the core 38 is suppressed. In addition, since it flows along the circumferential direction of the core body 38 without leaving the core body 38, the drying efficiency of the resin solution 50 applied to the core body 38 is higher than that of the comparative example in which the air is not sucked by the suction device 30. Improves and shortens drying time.

[Example]
Hereinafter, the first embodiment will be described in more detail by way of examples. Note that the first embodiment is not limited to the following examples.

  In this example, PI precursor solution (trade name: U varnish, Ube Industries, solid content concentration 18%, solvent is N-methylpyrrolidone) 100 parts by mass, carbon black (trade name: Special Black 4, Degussa Huls) 27% in terms of solid content mass ratio, and then dispersed by a counter collision type disperser (Geanus PY, manufactured by Genus Co., Ltd.) to obtain a resin solution 50 having a viscosity of about 42 Pa · s at 25 ° C.

  A SUS304 cylinder having an outer diameter of 600 mm, a wall thickness of 10 mm, and a length of 0.6 m was used as the core body 38. The outer peripheral surface of the core body 38 was roughened to Ra 0.4 μm by blasting with spherical alumina particles.

  A masking member (trade name: Scotch tape # 232, manufactured by Sumitomo 3M Limited and having a width of 24 mm made of a crepe paper base material and an acrylic adhesive material) was attached to both ends of the core body 38 on the entire circumference.

  Next, a PI precursor coating film is formed by the spiral coating method shown in FIG. Application is performed by connecting a MONO pump as a pump 56 to a tank 54 containing 10 L of the resin solution 50, discharging 60 ml per minute from the flow down device 52, rotating the core 38 in the direction of arrow B at 20 rpm, After the resin solution 50 from 52 adheres to the core body 38, the spatula 60 is pressed against the outer peripheral surface thereof and moved in the axial direction of the core body 38 (arrow C direction) at a speed of 50 mm / min. The spatula 60, which is a smoothing means, is obtained by processing a stainless steel plate having a thickness of 0.2 mm into a width of 20 mm and a length of 50 mm. The coating width was from the position of the end 10 mm of the core body 38 to the position of the other end 10 mm.

  By continuing to rotate for 5 minutes after coating, the spiral streaks on the coating film surface disappeared. As a result, a layer having a thickness of about 500 μm was formed. This thickness corresponds to a finished film thickness of 80 μm.

  Thereafter, as shown in FIG. 3, the core 38 was rotated at 10 rpm (circumferential speed 0.1 m / s) and placed in the drying furnace 26 set at 150 ° C. A HEPA filter 29 is provided at the air outlet of the air blowing unit 28 provided at the upper part of the drying furnace 26, and 1.2 m / s hot air blows down toward the lower part of the drying furnace 26 through the HEPA filter 29. It has become.

The nozzle 16 of the blower 12 provided in the drying furnace 26 has a blower opening 14 having a width of 1.5 mm and a length of 1.2 m. Air heated to 150 ° C. is blown from the blower 18 at a flow rate of 0.1 m ³ / s, and hot air at 150 ° C. is blown out from the blower opening 14 of the nozzle 16 at a wind speed of 50 m / s. The angle of the nozzle 16 with respect to the core body 38 is adjusted so that the hot air from the air blowing port 14 of the nozzle 16 strikes at right angles to the outer peripheral surface of the core body 38. Moreover, the nozzle 16 was installed so that the distance d of the core body 38 and the ventilation port 14 might be set to 50 mm. The velocity of the hot air at the position where it hits the core 38 was 20 m / s, and the temperature was 150 ° C., the same as the set temperature of the drying furnace 26.

The nozzle 34 of the suction device 30 provided in the drying furnace 26 has a suction port 32 having a width of 1.5 mm and a length of 1.2 m. The suction unit 36 sucks air having a flow rate of 0.5 m ³ / s from the suction port 32.

  The nozzle 16 of the blower device 12 and the nozzle 34 of the suction device 30 are disposed at a position 180 ° away from the central axis of the core body 38. When the coating film (resin solution 50) was dried for 5 minutes under these conditions, the residual solvent ratio of the coating film could be dried to 40%. After taking out the core body 38, the masking member was peeled off. The residual solvent ratio is (the amount of solvent in the dried coating film) / (the amount of solvent contained in the applied coating film).

  After that, as shown in FIG. 8, the core member 38 was lowered from the turntable so as to be vertical, and the shielding member 82 was placed on the core member 38. Its shape is an outer diameter of 600 mm, a height of 120 mm, a hole of 150φ is provided in the center, and a 1 mm thick SUS304 plate is processed.

  The core body 38 was put in a heating furnace 80 and reacted by heating at 200 ° C. for 30 minutes and at 300 ° C. for 30 minutes, and drying of the residual solvent and imidization reaction of the resin were simultaneously performed.

  After cooling to room temperature, pressurized air was blown into the gap between the core 38 and the film to remove the resin film, and an intermediate transfer belt (endless belt) was obtained. When the film thickness was measured with a dial gauge, the average was 80 μm.

  When the electrical characteristics of the obtained intermediate transfer belt were measured by the method described later, the surface resistivity was 10.8 LogΩ / □ on average and the variation (difference between the maximum value and the minimum value) was 0.2. The required value of the surface resistivity is 10.8 LogΩ / □ on average, and the variation is required to be within 0.4. The variation is considered to be caused by uneven drying.

[Comparative example]
In the comparative example, the core body 38 was dried in the drying step in the above-described example in a state where the suction device 30 was stopped (a state where the suction flow rate was set to 0 m ³ / s from the suction port 32). The other conditions are the same as in the above example. When the coating film was dried under these conditions for 5 minutes, the residual solvent ratio of the coating film was 45%, which was different from the examples. Therefore, in order to match the dry state with the above examples, the coating film was dried for 6 minutes. The residual solvent ratio could be dried to 40%. In other respects, the baking step was performed in the same manner as in the above-described example to obtain an intermediate transfer belt (endless belt). When the film thickness was measured with a dial gauge, the average was 80 μm.

  When the electrical characteristics of the obtained intermediate transfer belt were measured by the method described later, the average surface resistivity was 10.8 LogΩ / □, and the variation (difference between the maximum value and the minimum value) was 0.6.

  Thus, in the said Example, compared with the comparative example, it turned out that required drying time is shortened and the dispersion | variation in surface resistivity becomes small.

(Measurement method of surface resistivity)
The surface resistivity is a numerical value obtained by dividing the electric potential gradient in the direction parallel to the current flowing along the surface of the test piece by the current per unit width of the surface. Equal to the surface resistance between the two electrodes. The unit of surface resistivity is formally Ω, but is written as Ω / □ to distinguish it from simple resistance.

  For measurement, a digital ultra-high resistance / microammeter (manufactured by Advantest, R8340A), double ring electrode UR probe: MCP-HTP12, and register table: UFL MCP-ST03 (both manufactured by Dia Instruments) In accordance with JIS K6911 (1995), a voltage was applied to the ring electrode.

  At the time of measurement, a test piece is placed on the register table, the UR probe is applied so as to contact the measurement surface, and a mass of 2.0 ± 0.1 kg (19.6 ± 1.0 N) is placed on the UR probe. A weight was attached so that a constant load was applied to the test piece. The voltage application time during measurement was 10 seconds.

  If the reading of the R8340A digital ultra-high resistance / microammeter is R and the surface resistivity correction coefficient of the UR probe MCP-HTP12 is RCF (S), RCF (S ) = 10.0, the surface resistivity ρs is expressed by the following formula (1).

  Formula (1): ρs (Ω / □) = R × RCF (S) = R × 10.0

(Modification of the first embodiment)
In the first embodiment, as illustrated in FIG. 3, the nozzle 16 is disposed above the rotation axis of the core body 38, but the nozzle 16 is, for example, below the rotation axis of the core body 38. It may be arranged on the side or may be arranged at any position in the circumferential direction of the core body 38.

  In the first embodiment, the air blower 12 (nozzle 16) and the suction device 30 (nozzle 34) are arranged at positions 180 degrees away from the central axis of the core body 38. The suction device 30 is not limited, and the suction device 30 may be disposed at a position opposite to the blower device 12 with respect to the rotation center C of the core body 38 (on the right side of the alternate long and short dash line A in FIG. 4). That is, it is only necessary that the blower 12 (nozzle 16) and the suction device 30 (nozzle 34) be disposed at a position 90 ° or more away from the central axis of the core body 38. In other words, a line segment connecting the center of the nozzle 16 in the width direction of the air blowing port 14 and the rotation center C of the core body 38, the center of the suction port 32 of the nozzle 34 in the width direction and the rotation center C of the core body 38. The angle formed by the line segment connecting the two and the like may be 90 ° or more and 180 ° or less.

  Moreover, in 1st Embodiment, although it was set as the structure by which the wind from the ventilation port 14 is applied to the outer peripheral surface of the core body 38 toward the rotation center C of the core body 38, as FIG. 8 shows, The air from the air outlet 14 may be configured to be applied to the outer peripheral surface of the core body 38 in the tangential direction of the core body 38. In this case, for example, the suction port 32 of the nozzle 34 of the suction device 30 is configured to face the tangential direction of the core body 38 and suck the wind from the blower port 14.

  Furthermore, in the first embodiment, the drying device 10 includes the single suction device 30, but as illustrated in FIG. 9, a plurality of suction devices 30 are arranged along the circumferential direction of the core body 38. It may be a configuration. Specifically, the drying device 10 includes, for example, suction devices 30A and 30B as an example of suction means for sucking wind that hits the outer peripheral surface of the core body 38 from both sides of the nozzle 16 of the blower device 12. The nozzle 34 of the suction device 30A is divided by hitting the outer peripheral surface of the core body 38 from the air blowing port 14 of the nozzle 16 and sucks the wind that has flowed in one circumferential direction. The nozzle 34 of the suction device 30B It is divided by hitting the outer peripheral surface of the core body 38 from the air blowing port 14 and sucks the wind that flows to the other circumferential side.

[Second Embodiment]
Next, a method for manufacturing the intermediate transfer belt according to the second embodiment will be described. In addition, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted suitably about the part same as 1st Embodiment.

  The manufacturing method of the intermediate transfer belt according to the second embodiment includes an application process, a drying process, a baking process, and a removal process, as in the manufacturing method of the first embodiment. Since the application step, the firing step, and the removal step are the same as the application step, the firing step, and the removal step in the manufacturing method of the first embodiment, a description thereof will be omitted, and the drying step will be described below.

(Drying process of the second embodiment)
In the drying process of the second embodiment, the resin solution 50 applied to the core body 38 in the application process is dried by the following drying device 200 to form a film on the outer peripheral surface of the core body 38.

  As shown in FIG. 10, the drying device 200 is arranged along the axial direction of the core body 38 in addition to the drying furnace 26, the rotation device 43, the blower device 12, and the suction device 30 in the drying device 10 of the first embodiment. A far-infrared heater 70 is provided as an example of the arranged infrared generation means. The far-infrared heater 70 is disposed, for example, so as to sandwich the core body 38 in the radial direction, and the radiant heat from the far-infrared heater 70 is directed from the outside of the core body 38 toward the outer peripheral surface of the core body 38. Are emitted. The axial length of the heating region in the far-infrared heater 70 is not less than the axial length of the coating region 38A (see FIG. 2) in the core body 38.

  The drying apparatus 200 includes a control unit 90 as an example of a control unit that controls driving of the far-infrared heater 70, the blower 12, and the suction device 30. The control unit 90 stops the far-infrared heater 70 until a later-described constant rate drying period of the resin solution 50, and the resin solution 50 is dried by the blower 12 and the suction device 30. Stops the air blower 12 and the suction device 30 and the far infrared heater 70 dries the resin solution 50.

  Here, the drying period in the drying process of the resin solution 50 will be described.

  The drying period in the drying process of the resin solution 50 is divided into three periods as shown in FIG. The period of initial A is a period until the material reaches the dynamic equilibrium temperature, and is referred to as a material preheating period. The period of the middle period B is a period in which the solvent reduction rate takes a constant value and is referred to as a constant rate drying period. The period of the latter period C is a period in which the drying speed gradually decreases, and is referred to as a reduced rate drying period.

  Here, the residual solvent ratio = (amount of solvent in the dried coating film) / (amount of solvent contained in the applied coating film) is defined. The material preheating period is affected by the heat capacity of the substrate, the material, and the drying conditions, but in most cases it is much shorter than the fixed rate drying period or the reduced rate drying period, so it is considered together with the fixed rate drying period. I will do it. The boundary between the constant rate drying period and the reduced rate drying period varies depending on the material, but can be determined by measuring the weight loss of the solvent during drying.

  FIG. 11 shows, as an example of the state of solvent reduction in the drying process, the solvent reduction state in the drying process in the case of using the polyimide resin precursor solution of Examples described later. In the example shown in FIG. 11, the place where the residual solvent ratio is 15% is the changing point between the constant rate drying period and the reduced rate drying period.

  The relationship between the diffusion rate τA of the solvent gas volatilized from the coating film and the diffusion rate τB of the solvent moving from the inside of the coating film to the surface is τA <τB in the constant rate drying period in which the coating film contains a large amount of solvent. That is, in the constant rate drying period, τA dominates the solvent reduction rate (drying rate). Since it is the wind during drying that promotes the diffusion of the solvent gas, the drying efficiency increases by increasing the wind speed.

  Also, as drying of the coating proceeds and τB decreases as the amount of solvent in the coating decreases, τA> τB in the later stage of drying, and from this point, drying shifts to a reduced rate drying period. Since it is the heat in drying that promotes solvent diffusion inside the coating film, increasing the heating efficiency increases the drying efficiency.

  In the present embodiment, the blower 12 is used as an effective means for increasing the wind speed, and the far infrared heater 70 is used as an effective means for increasing the heating efficiency.

[Example]
Hereinafter, the second embodiment will be described in more detail by way of examples. Note that the second embodiment is not limited to the following examples. Here, a different part from the Example in 1st Embodiment is demonstrated, and description is abbreviate | omitted suitably about the part same as the Example in 1st Embodiment.

  In this example, a cylinder having an outer diameter of 300 mm and a wall thickness of 5 mm was used as the core body 38, and the PI precursor solution was applied to the cylinder with a thickness of about 300 μm. The other application conditions were the same as those in the example of the first embodiment.

In the constant rate drying period, the air heated to 140 ° C. from the blowing unit 18 was blown at a flow rate of 4 m ³ / min, and sucked by the suction device 30 to be dried.

  In the decreasing rate drying period, drying was performed at 170 ° C. using a far infrared heater (manufactured by Noritake Company Limited: PLR heater). The other drying conditions were the same as those in the example of the first embodiment. In the examples, the drying time to reach a residual solvent ratio of 5% was 4 minutes.

[Comparative Example 1]
In Comparative Example 1, application was performed under the same conditions as in the example, and then drying was performed at 140 ° C. using only the drying furnace 26 without using the blower 12, the suction device 30, and the far infrared heater 70. In Comparative Example 1, the drying time to reach 5% residual solvent was 13 minutes.

[Comparative Example 2]
In Comparative Example 2, after coating was performed under the same conditions as in the example, drying was performed only with the blower 12 and the suction device 30 without drying with the far infrared heater 70. In Comparative Example 2, the drying time until reaching a residual solvent ratio of 5% was 5 minutes.

[Comparative Example 3]
In Comparative Example 3, after coating was performed under the same conditions as in the example, drying was performed only with the far-infrared heater 70 without drying with the blower 12 and the suction device 30. In Comparative Example 3, the drying time until reaching a residual solvent ratio of 5% was 11 minutes.

  As mentioned above, in the case of the Example which concerns on 2nd Embodiment, compared with the case of Comparative Examples 1-3, drying efficiency improves and the drying time until it reaches a residual solvent rate of 5% is shortened. I understood.

  Also in the second embodiment, the modification in the first embodiment can be applied.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made. For example, the modification examples described above may be appropriately combined.

10 Drying device 12 Blower (an example of wind generating means)
14 Air outlet 30 Suction device (an example of suction means)
30A suction device (an example of suction means)
30B Suction device (an example of suction means)
32 Suction port 38 Core 38A Application region 43 Rotating device (an example of rotating means)
50 Resin solution 70 Far infrared heater (an example of infrared generating means)
90 control unit (an example of control means)
200 Drying equipment

Claims (4)

A rotating means for rotating a cylindrical or columnar core having a solution applied to the outer peripheral surface about an axis;
The length in the longitudinal direction along the axial direction of the core is greater than or equal to the length of the solution application region on the outer peripheral surface of the core, and the length in the short direction is smaller than the diameter of the core. A wind generating means that has an air outlet and blows the solution from the air outlet;
The length in the longitudinal direction along the axial direction of the core is greater than or equal to the length of the solution application region on the outer peripheral surface of the core, and the length in the short direction is smaller than the diameter of the core. A suction means having a suction port, disposed at a position opposite to the wind generating means with respect to the center of rotation of the core, and sucking the wind that has hit the solution through the suction port;
A drying apparatus comprising: A rotating means for rotating a cylindrical or columnar core having a solution applied to the outer peripheral surface about an axis;
The length in the longitudinal direction along the axial direction of the core is greater than or equal to the length of the solution application region on the outer peripheral surface of the core, and the length in the short direction is smaller than the diameter of the core. A wind generating means that has an air outlet and blows the solution from the air outlet;
The length in the longitudinal direction along the axial direction of the core is greater than or equal to the length of the solution application region on the outer peripheral surface of the core, and the length in the short direction is smaller than the diameter of the core. A plurality of suction ports that are arranged along the circumferential direction of the core, and a suction unit that sucks the wind that hits the solution from both sides of the wind generation unit at the suction port;
A drying apparatus comprising: Furthermore, infrared generation means arranged along the axial direction of the core,
Control means for controlling the wind generation means and the infrared generation means,
The control means includes
The infrared ray generating means is stopped until the constant rate drying period of the solution, the solution is dried by the wind generating means,
3. The drying apparatus according to claim 1, wherein the wind generation unit is stopped during the decreasing rate drying period of the solution, and the solution is dried by the infrared generation unit. An application step of applying a solution to the outer peripheral surface of a cylindrical or columnar core;
A drying step of drying the solution by the drying device according to any one of claims 1 to 3 to form a film on the outer peripheral surface of the core;
A process for producing an endless belt having

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