JP6191439B2 - Cooling apparatus and tubular body manufacturing apparatus - Google Patents

Description

  The present invention relates to a cooling device and a tubular body manufacturing apparatus.

  In Patent Document 1, a molten tubular film extruded from an annular die slit formed between an outer peripheral surface of a mandrel of an annular extrusion die and an inner peripheral surface of a ring member is supported on the mandrel of the annular extrusion die. A method for forming a tubular film that forms a tubular film having a predetermined inner diameter by passing the sizing portion of a sizing mandrel attached concentrically through an outer peripheral surface of the sizing mandrel while being cooled with internal cooling water from at least the inside. The inner surface of the tubular film is made to circulate internal cooling water in a direction opposite to the traveling direction of the tubular film so that a water film is formed in the gap between the outer peripheral surface of the sizing portion and the inner surface of the tubular film. A method for forming a tubular film characterized in that is cooled.

  In Patent Document 2, a thermoplastic resin tube plasticized by an extruder and extruded into a tube shape from a cylindrical die is placed along the outer peripheral surface of a sizing die having an outer diameter corresponding to the finished inner diameter of the thermoplastic resin tube. A method of manufacturing a thermoplastic resin tube that is formed into the finished inner diameter while being cooled and cooled, and is cut off from the upper outer periphery of the sizing die, and the outer peripheral surface of the sizing die and the thermoplastic resin tube. A manufacturing method of a thermoplastic resin tube is disclosed, in which cooling water is allowed to flow between the inner peripheral surface and the inner peripheral surface.

  Patent Document 3 includes a sizing portion having a predetermined diameter, and a film having a predetermined inner diameter is formed by passing a molten parison extruded from an annular extrusion die while being cooled by internal cooling water. A tubular film characterized in that the contact angle with the cooling water of the material constituting at least the sizing part of the sizing mandrel is smaller than the contact angle with the cooling water of the film. A sizing mandrel for molding is disclosed.

JP 2000-033641 A JP 2002-200665 A JP 11-179790 A

  An object of the present invention is to provide a cooling device capable of obtaining a tubular body having excellent shape accuracy.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1
A cooling member that has a porosity in at least a part of the outer peripheral surface, and cools a tubular melt containing a molten thermoplastic resin extruded from a die provided in an extrusion device from the inner peripheral surface side of the melt;
A mechanism for ejecting a pressurized medium that is a gas from the porous toward the inner peripheral surface of the melt;
A mechanism for supplying a coolant, which is a medium different from the pressurized medium, to the cooling member, and cooling the cooling member;
Is a cooling device.

The invention according to claim 2
The cooling device according to claim 1, wherein the refrigerant is a liquid.
The invention according to claim 3
The cooling member is located on the most upstream side in the extrusion direction of the melt and has a first region that does not have the porosity on the outer peripheral surface, and on the downstream side in the extrusion direction of the melt from the first region. The cooling device according to claim 1, further comprising: a second region that is located and has the porosity on an outer peripheral surface thereof.

The invention according to claim 4
The temperature of the said pressurization medium is a cooling device of any one of Claims 1-3 which is lower than the temperature of the said refrigerant | coolant .

The invention according to claim 5
An extrusion apparatus for extruding a melt containing a molten thermoplastic resin into a tubular shape from a die;
The cooling device according to any one of claims 1 to 4 , wherein the melt extruded in a tubular shape from the base is cooled from the inner peripheral surface side of the melt to form a tubular body.
A drawing device for pulling out the tubular body in the extrusion direction of the melt;
The manufacturing apparatus of the tubular body which has this.

According to the first aspect of the present invention, a tubular body with excellent shape accuracy can be obtained as compared with the case where the mechanism for ejecting a pressurized medium that is a gas is not provided.

According to the invention which concerns on Claim 3 , the tubular body by which the wave | undulation was suppressed compared with the case where said 1st area | region has the said porosity is obtained.

According to the invention of claim 4, wherein as compared with the case where the temperature of the pressurizing medium is higher than the temperature of the same case or the coolant temperature of the coolant, less variation tubular body of the electric resistance value can be obtained.

According to the invention which concerns on Claim 5 , compared with the case where the cooling device does not have the said mechanism which ejects the pressurized medium which is gas , the tubular body excellent in the shape precision is obtained.

It is a schematic sectional drawing which shows an example of the manufacturing apparatus of the tubular body which concerns on this embodiment. It is the schematic sectional drawing which expanded the cooling device periphery in the manufacturing apparatus of the tubular body of FIG. It is the schematic sectional drawing which expanded the cooling device periphery in another example of the manufacturing apparatus of the tubular body which concerns on this embodiment. It is the schematic sectional drawing which expanded the cooling device periphery in another example of the manufacturing apparatus of the tubular body which concerns on this embodiment.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
<Tube manufacturing apparatus>
First, the tubular body manufacturing apparatus according to the first embodiment will be described as an example of a tubular body manufacturing apparatus using the cooling device according to the present embodiment.
FIG. 1 is a cross-sectional view schematically showing a configuration of a tubular body manufacturing apparatus 100 according to the present embodiment. FIG. 2 is a configuration around a cooling device (cooling unit) in the tubular body manufacturing apparatus 100 shown in FIG. It is sectional drawing which expands and shows roughly. Note that the drawings referred to below are used for explaining the present embodiment, and do not show the actual size ratio.

  As shown in FIG. 1, the tubular body manufacturing apparatus 100 includes an extrusion apparatus 110 that extrudes a molten body F containing a molten (dissolved) thermoplastic resin downward from a base 20 (annular die), and a tubular form from the base 20. A cooling device 30 that cools the extruded melt F from the inner peripheral surface side of the melt F, a support member 70 that supports the cooling device 30, and a tubular body obtained by cooling the melt F by the cooling device 30 And a drawing machine 50 (drawing device) for drawing T in the extrusion direction of the melt F.

(Extruder)
As shown in FIG. 1, the extrusion apparatus 110 includes a uniaxial extruder 10 in which a resin material P containing a thermoplastic resin is melted to form a melt F, and a die 20 attached to the tip of the uniaxial extruder 10. And.

  The uniaxial extruder 10 includes a heating cylinder 12 having a heater (not shown) for heating the resin material P, a charging port 11 provided in the heating cylinder 12 and charged with the resin material P, and a resin provided in the heating cylinder 12. And a screw 13 as a conveying member that conveys the melt F in which the material P is melted to the base 20.

  In the single screw extruder 10, the resin material P charged into the heating cylinder 12 through the charging port 11 is heated by the heater of the heating cylinder 12 at a temperature equal to or higher than the melting temperature of the resin material P (usually 150 to 450 ° C.). The screw 13 is conveyed (supplied) to the base 20 while being melted by the heat generated by the screw rotation. In the single screw extruder 10, the resin material P (pellet) formed in a granular shape is fed into the charging port 11.

  As shown in FIG. 1, the die 20 passes through the flow path 22 through which the molten F flowing in from the heating cylinder 12 passes through the inside of the heating cylinder 12 of the single screw extruder 10 and the flow path 22. An annular (circular) outlet hole 23 is formed for extruding the molten F in a molten state into a tubular shape.

  In the base 20, the melt F in a molten state flows into the flow path 22 from the tip of the heating cylinder 12 and passes through the flow path 22, and is driven by the propulsive force (conveyance force) due to the rotation of the screw 13 of the single screw extruder 10. The tube is extruded from the outlet hole 23 into a tubular shape.

(Support member)
As shown in FIG. 1, the support member 70 is formed in a columnar shape, penetrates the base 20 at the radial center (center) of the outlet hole 23 formed in an annular shape in the base 20, and It is supported so as to protrude upward and downward.

(Cooling system)
As shown in FIG. 2, the cooling device 30 includes a cooling member 32 that cools the melt F from the inner peripheral surface side of the melt F, and an inner peripheral surface of the melt F from the porosity of the outer peripheral surface 34 of the cooling member 32. A supply pipe 48 that supplies a pressurized medium that is a gas or a liquid to be ejected toward the inside to a cavity 37 provided inside the cooling member 32, and a refrigerant that cools the cooling member 32 is provided inside the cooling member 32. And a supply pipe 44 for supplying the cavity 42 to the cavity 42 and a discharge pipe 46 for discharging the refrigerant from the cavity 42.

The cooling member 32 is formed in a cylindrical shape, for example, and is disposed coaxially with the support member 70 so that the inner peripheral surface thereof contacts the outer peripheral surface of the support member 70, thereby penetrating the cooling member 32 in the axial direction. It is supported by the support member 70.
In the cooling member 32, as shown in FIG. 2, the outermost peripheral wall 36 constituting the outer peripheral surface 34 is made of a porous material that allows gas or liquid to pass therethrough, so that the outer peripheral surface 34 is porous. Is formed. A cavity 37 to which a pressurized medium is supplied from a supply pipe 48 is provided in contact with the inner peripheral surface of the outermost peripheral wall 36 on the radial center side of the outermost peripheral wall 36. Furthermore, as described above, a cavity 42 to which a coolant is supplied is provided inside the cooling member 32 (further in the radial direction than the cavity 37), and gas and liquid are transmitted between the cavity 37 and the cavity 42. A boundary wall 38 that is not allowed is provided.

Although the thickness of the outermost peripheral wall 36 comprised with the porous material is not specifically limited, For example, the range of 3 mm or more and 10 mm or less is mentioned.
The porous material is not particularly limited as long as it is a material that can withstand the temperature of the cooling member 32 (for example, a range of 30 ° C. or more and 250 ° C. or less) when the melt F is cooled. Specific examples of the porous material include, for example, a sintered body obtained by sintering metal powder, a porous metal body having a structure in which a metal mesh is stacked, a porous metal body having a honeycomb structure, and a porous ceramic sintered body. (For example, metal oxides such as alumina), porous cement molded bodies, and the like.

  Note that the cooling member 32 of the present embodiment has a configuration in which the outermost peripheral wall 36 is made of a porous material so that the outer peripheral surface 34 is porous. However, the cooling member 32 is not limited to this configuration. For example, the cooling shown in FIG. Like the cooling member 62 of the device 60, the outermost peripheral wall 66 constituting the outer peripheral surface 64 may be a perforated plate in which a plurality of through holes are provided to form a hole.

  Specifically, the cooling member 62 shown in FIG. 3 includes an outermost peripheral wall 66 that is a perforated plate formed with a plurality of through holes and a cavity 67 in which a pressurized medium is supplied from a supply pipe 48. And a boundary wall 68 that is provided between the cavity 67 and the cavity 42 and does not allow gas and liquid to pass therethrough. The through direction of the through hole provided in the perforated plate is not particularly limited, but it is desirable that the direction is closer to the radial direction of the melt F, and the radial direction is particularly desirable.

  The material of the outermost peripheral wall 66 that is a perforated plate provided with a large number of through holes is not particularly limited as long as it is a material that can withstand the temperature of the cooling member 62 when the melt F is cooled. Examples include metal materials such as steel.

Here, “porous” is a large number of pores formed on the surface, and the diameter of each pore constituting the pore includes, for example, a range of 10 μm or more and 1000 μm or less. As a rate (area ratio which a hole occupies), the range of 10% or more and 50% or less is mentioned, for example.
In addition, the pores only need to be scattered in the outer peripheral surface 34 of the cooling member 32, and the number and distribution of the holes are not particularly limited. From the viewpoint of improving the shape accuracy of the tubular body T, cooling is performed. It is desirable that holes are scattered throughout the entire circumferential direction of the outer circumferential surface 34 of the member 32. That is, it is desirable that the hole area ratio of the holes forming the pores does not change significantly in the circumferential direction of the cooling member 32.

Next, a mechanism for ejecting the pressurized medium from the porosity of the outer peripheral surface 34 of the cooling member 32 toward the inner peripheral surface of the melt F will be described.
The supply pipe 48 for supplying the pressure medium to the cooling member 32 is connected to a pressure machine (not shown) at one end and passes through the inside of the support member 70 along the axial direction of the support member 70, and then the cavity 42 and boundary The other end is connected to the cavity 37 through the wall 38.

The pressurizing medium is fed into the cavity 37 of the cooling member 32 through the supply pipe 48 by the pressure applied by the pressurizer (not shown), passes through the hole in the outermost peripheral wall 36, and the outer periphery of the outermost peripheral wall 36. It is ejected from the porous surface 34 toward the inner peripheral surface of the melt F.
In the present embodiment, it is only necessary to have a mechanism for ejecting the pressurized medium from the porous toward the inner peripheral surface of the melt F, and the pressurized medium is actually ejected from the porous when the melt F is cooled. The form is not limited. That is, for example, even when the melt F passes while contacting the outer peripheral surface 34 of the cooling member 32 and the pores are blocked by the melt F and the pressurized medium is not ejected, the mechanism that ejects the pressurized medium from the pores is used. It is sufficient that pressure is applied to the inner peripheral surface side of the melt F.

  The type of the pressurizing medium is not particularly limited as long as it is a gas or a liquid and passes through the perforation of the outer peripheral surface 34. Specific examples of the pressurizing medium include air, inert gases such as nitrogen and argon, compounds used as refrigerants described later such as water and ethylene glycol aqueous solution, and the like.

Among them, the pressure medium is preferably a gas from the viewpoint of ease of handling after the pressure medium is ejected from the pores. Further, for example, when the pressurized medium is a liquid, it is conceivable that the liquid ejected from the perforation accumulates on the cooling member 32 along the outer peripheral surface 34 of the cooling member 32. In that case, for example, before the melt F is cooled by the cooling member 32, when the melt F is rapidly cooled by contact with the liquid accumulated in the upper portion of the cooling member 32, the melt F is ejected from the pores. It is also conceivable that the effect of the pressurized medium is difficult to obtain. From this point of view, the pressurized medium is preferably a gas.
Further, from the viewpoint of handleability of the pressurized medium, the pressurized medium is preferably air or the same compound as the refrigerant.

The type of the pressurizer (not shown) is not particularly limited, and includes, for example, a pressurization pump, and is selected according to the type of pressurization medium.
The pressure applied to the pressurizing medium by the pressurizing pump is set according to the viscosity of the pressurizing medium, the structure of the porous material on the outermost peripheral wall 36, the size of individual pores in the pores, the open area ratio, etc. Is done. Specifically, for example, when the pressure medium is a gas, the pressure applied to the pressure medium includes a range of 0.01 MPa to 0.1 MPa. When the pressure medium is a liquid, the pressure applied to the pressure medium The range is 0.01 MPa or more and 0.1 MPa or less.

Next, a mechanism for cooling the cooling member 32 will be described.
The supply pipe 44 for supplying the coolant for cooling the cooling member 32 to the cavity 42 and the discharge pipe 46 for discharging the coolant from the cavity 42 are both connected to a cooler (not shown), and the axial direction of the support member 70 And the other end is connected to the cavity 42.
The refrigerant is cooled by the cooler (not shown) and then supplied to the cavity 42 through the supply pipe 44 to cool the cooling member 32 and the temperature of the cooling member 32 is adjusted. The refrigerant that has cooled the cooling member is discharged from the cavity 42 through the discharge pipe 46 to the outside of the cooling member 32, and returned to the cooler (not shown) to be cooled again.

As described above, the cooling member 32 is cooled to the temperature of the refrigerant cooled by the cooler. That is, the temperature of the cooling member 32 is controlled by adjusting the temperature of the refrigerant.
The refrigerant is not particularly limited, and examples thereof include water, a water bath solution (brine) of ethylene glycol or propylene glycol, and the like.
In the present embodiment, the cooling member 32 is cooled using a refrigerant. However, the cooling means is not particularly limited as long as the cooling member 32 is cooled.

(Drawer)
As shown in FIG. 1, the drawer 50 is provided around the support member 70 and supports the tubular body T from the inner peripheral surface side of the tubular body T obtained by cooling the melt F by the cooling device 30. An inner roll 52 and an outer roll 54 that supports the tubular body T from the outer peripheral surface side of the tubular body T are provided.
In the drawer 50, the tubular body T is sandwiched between the inner roll 52 and the outer roll 54, and the inner roll 52 and the outer roll 54 rotate, whereby the tubular body T is pulled out in the extrusion direction of the melt F. Yes.

<Method for producing tubular body>
Next, the manufacturing method which manufactures the thermoplastic resin tube as an example of a tubular body using the above-mentioned tubular body manufacturing apparatus 100 is demonstrated.

  First, the resin material P (pellet) is charged into the heating cylinder 12 from the charging port 11 of the single screw extruder 10 (see FIG. 1), and the resin material P is fed by a plurality of heaters (not shown) of the heating cylinder 12. The resin material P is heated to a temperature equal to or higher than the melting temperature of the resin material P (usually 150 to 450 ° C.) to obtain a molten state F (heating step).

  Next, as shown in FIG. 1, the melt F in a molten state is caused to pass through the flow path 22 of the base 20 from the heating cylinder 12 by the propulsive force of the screw 13 inside the heating cylinder 12. Extruded into a tube from the outlet hole 23 (extrusion process).

Next, the molten body F extruded in a tubular shape from the outlet hole 23 of the base 20 is cooled from the inner peripheral surface side of the molten body F by the cooling device 30 and hardened to obtain the tubular body T. (Cooling process).
Specifically, when the melt F extruded in a tubular shape from the outlet hole 23 of the base 20 passes through the outer periphery of the cooling member 32, the pores in the outer peripheral surface 34 of the cooling member 32 are changed to the inner peripheral surface of the melt F. The melt F is cooled while pressure is applied to the outside by the pressurized medium ejected toward it.
The inner peripheral surface of the melt F only needs to be pressurized outward by the pressurized medium ejected from the pore as described above, and the inner peripheral surface of the melt F is applied to the outer peripheral surface 34 of the cooling member 32. Direct contact or no direct contact may be required. When the inner peripheral surface of the melt F is not in direct contact with the outer peripheral surface 34 of the cooling member 32, the pressurization medium cools the melt F by taking the heat of the melt F, and when the melt F is in direct contact, pressurization is performed. The medium F and the cooling member 32 take the heat of the melt F, so that the melt F is cooled.

Next, the obtained tubular body T is continuously pulled out by the drawer 50 (drawing step). Specifically, while the tubular body T is sandwiched between the inner roll 52 and the outer roll 54, the tubular body T is tensioned by rotating the inner roll 52 and the outer roll 54, and the shape of the tubular body T is maintained in a tubular shape. Pull out continuously.
Thus, in this embodiment, the tubular body which is a thermoplastic resin tube (cylindrical film) is manufactured.

In the present embodiment, as described above, the outer peripheral surface 34 of the cooling member 32 is provided with a hole, and the pressurized medium is ejected from the hole toward the inner peripheral surface of the melt F. Therefore, the shape accuracy is excellent. A tubular body T is obtained.
Specifically, for example, when a cooling member that does not have porosity on the outer peripheral surface is used, the frictional force between the outer peripheral surface of the cooling member and the inner peripheral surface of the melt is large, and when the tubular body is pulled out by a drawer In addition, the tension applied to the tubular body is too large, and distortion occurs.

  On the other hand, in the present embodiment, the melt F located on the outer periphery of the cooling member 32 has a mechanism in which the pressurized medium is ejected from the porosity of the outer peripheral surface 34 of the cooling member toward the inner peripheral surface of the melt F. The pressure is applied in the direction in which the material is pushed outward (that is, the diameter of the melt F expands). Therefore, the frictional force applied between the outer peripheral surface 34 of the cooling member 32 and the inner peripheral surface of the melt F is reduced, and the tension applied when the tubular body T is pulled out by the drawer 50 is difficult to increase, and distortion occurs. It is considered difficult to obtain a tubular body T having an excellent shape system. Further, depending on conditions such as pressure applied to the pressurized medium, the contact area between the outer peripheral surface 34 of the cooling member 32 and the inner peripheral surface of the melt F is reduced, and the outer peripheral surface 34 of the cooling member 32 and the inner peripheral surface of the melt F are reduced. The tubular body T having an excellent shape system is obtained.

  When the tubular body of the present embodiment is used, for example, in an intermediate transfer belt of an image forming apparatus, the pressure irregularity when the tubular body is brought into contact with the photoreceptor or the recording medium due to the excellent shape accuracy of the tubular body. And transferability is improved. In addition, since the tubular body of the present embodiment has high flatness (excellent shape accuracy), there is little variation in contact with the cleaning member, and cleaning properties are improved. Therefore, an image obtained by the image forming apparatus using the tubular body of the present embodiment is one in which unevenness in density and image omission are suppressed.

Here, “the shape accuracy is excellent” means that the undulation is small and the flatness is excellent.
“Waviness” is a value indicating the unevenness measured by a surface roughness meter as described later, and means that the smaller the waviness value, the better the shape accuracy. Specifically, the waviness value is preferably 0.2 μm or less, and more preferably 0.1 μm or less.

  Further, “excellent flatness” means that the straightness in the axial direction when stretched with two axes is small, and the straightness in the axial direction when stretched with two axes is, for example, as described later, It is a value indicating the difference when the obtained tubular body is stretched with two rolls and the surface position is measured in the axial direction with a laser displacement meter. And, the smaller the value of the straightness in the axial direction when stretched with two axes, the better the shape accuracy is. Specifically, the value of the straightness in the axial direction when stretched with two axes is 2 mm or less. It is preferable that it is 1 mm or less.

  In the present embodiment, it is desirable that the temperature of the pressurizing medium is lower than the temperature of the cooling member 32 (that is, the temperature of the refrigerant), thereby obtaining the tubular body T with less variation in electric resistance value. Specifically, for example, when the tubular body T contains a conductive agent, when the melt F is cooled and a partially crystallized region is generated, the conductive agent moves so as to avoid the crystallized region. As a result, it is conceivable that the conductive agent is unevenly distributed. On the other hand, when the temperature of the pressurizing medium is lower than the temperature of the cooling member 32, the cooling rate of the melt F is high, and the melt F is cured before the conductive agent is unevenly distributed. It is presumed that a tubular body T with less variation is obtained.

In addition, as a difference (temperature of the cooling member 32-temperature of a pressurization medium) between the temperature of the cooling member 32 and the temperature of a pressurization medium, 0 degreeC or more and 100 degrees C or less are mentioned, for example, 30 degreeC or more and 80 degrees C or less Is desirable.
The temperature of the pressure medium may be, for example, Tg-100 ° C. or higher and Tg (° C.) or lower, assuming that the glass transition temperature of the thermoplastic resin contained in the melt F is Tg (° C.).
Moreover, as temperature of the cooling member 32, Tg-15 degreeC or more and Tg (degreeC) or less are mentioned, for example.

  In the present embodiment, the melt F pushed out from the outlet hole 23 of the base 20 is cooled by the cooling device 30 and then drawn by the drawing machine 50. However, the invention is not limited to this. For example, a plurality of cooling devices are separated from each other. It may be provided and cooled in stages. Specifically, for example, the first cooling device and the second cooling device are provided separately from each other, and the melt F is cooled by the first cooling device and then cooled by the second cooling device. It is good also as a structure which obtains T. Further, when a plurality of cooling devices are used, it is only necessary that the outer peripheral surface of at least one of the plurality of cooling devices is porous.

  Further, the cooling member 32 shown in FIG. 2 has a boundary wall 38 that does not allow gas and liquid to pass therethrough, so that the pressurized medium and the refrigerant do not come into contact with each other. However, the present invention is not limited to this. Specifically, for example, the boundary wall 38 is not provided between the cavity 42 and the cavity 37 or a boundary wall that allows gas and liquid to pass through is provided, and the refrigerant supplied to the cavity 42 from the supply pipe 44 is pressurized as it is. It may be used as a medium and may be ejected from the outer peripheral surface 34 through the outermost peripheral wall 36.

  The thermoplastic resin contained in the resin material P used in the tubular body manufacturing apparatus 100 is not particularly limited. Specifically, for example, polyethylene (high density polyethylene, medium density polyethylene, low density polyethylene, linear low density) Polyethylene, etc.), polypropylene ethylene block or random copolymer, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyphenylene ether, modified polyphenylene ether, liquid crystalline polyester, polyethylene terephthalate, polysulfone, polyethersulfone, polyphenylene sulfide, poly Butylene terephthalate, polyetherimide, polyetheretherketone, polyvinylidene fluoride, ethylenetetrafluoroethylene copolymer, perfluoro Vinyl ether copolymer, is made of one or a mixture of these is used. Among them, particularly preferred are polyetherimide, polyphenylene sulfide, polyether ether ketone and the like having a high elastic modulus.

The resin material P may contain a conductive agent and other additives in addition to the thermoplastic resin as necessary.
Examples of the conductive agent include at least one selected from carbon black, graphite, carbon fiber, metal powder, conductive metal oxide, organic metal compound, organic metal salt, conductive polymer, and the like, or a mixture of several of these. The thing which becomes. Among these, carbon black is particularly preferable. Examples of the carbon black include carbon blacks such as acetylene black, furnace black, and channel black. In order not to impair the appearance of the tubular body, carbon black having a low volatile content is preferable, and it is preferable to use carbon black having a small particle diameter in terms of resistance stability. Here, “conductive” means that the volume resistivity is 10 ¹⁰ Ωcm or less.

  Other additives include, for example, antioxidants for improving thermal stability, lubricants for preventing biting during extrusion molding, and the like, so long as the properties of the tubular body are not changed. May be.

  Examples of the tubular body manufactured by the tubular body manufacturing apparatus of the present embodiment include, but are not limited to, a thermoplastic resin cylindrical film used in an electrostatic copying image forming apparatus. Specifically, for example, it is used for a cylindrical member that conveys a transfer member, an intermediate transfer cylindrical member that transfers toner from a first holding member to a second holding member, and the like.

[Second Embodiment]
<Extrusion molding device (tubular body manufacturing device)>
In the extrusion molding apparatus of the second embodiment, instead of the cooling device 30 provided in the tubular body manufacturing apparatus 100 of the first embodiment, the first region 82A and the outer circumferential surface 84B that do not have porosity on the outer circumferential surface 84A. This is a form using a cooling device 80 including a cooling member 82 having a porous second region 82B. Since matters other than the difference in the cooling device are the same as described above, description thereof will be omitted.

  FIG. 4 is a cross-sectional view schematically showing an enlarged configuration around the cooling device (cooling unit) in the tubular body manufacturing apparatus of the present embodiment. In addition, the same code | symbol is used about the structure similar to the tubular body manufacturing apparatus 100 which concerns on 1st Embodiment.

  As shown in FIG. 4, the cooling member 82 of the cooling device 80 includes a first region 82A and a second region 82B. In the first region 82A, since the outermost peripheral wall 86A is made of a material that does not allow gas and liquid to pass therethrough, the outer peripheral surface 84A has no porosity. On the other hand, in the second region 82B, since the outermost peripheral wall 86B is made of a porous material that allows gas or liquid to pass therethrough, the outer peripheral surface 84B is a porous region.

Further, similarly to the cooling member 32 of the cooling device 30, a cavity 42 to which a refrigerant is supplied is provided inside the cooling member 82, and in the second region 82B, the cavity 87B to which a pressurized medium is supplied is the most. It is provided in contact with the inner peripheral surface of the outer peripheral wall 86B. A boundary wall 88 that does not allow gas and liquid to pass therethrough is provided between the cavity 42 and the cavity 87B.
The supply pipe 48 that supplies the pressurized medium to the cooling member 82 passes through the cavity 42 and the boundary wall 88 from the support member 70, and has one end connected to the cavity 87 </ b> B. That is, in the cooling device 80, the pressurized medium is sent from the pressurizer (not shown) connected to the other end of the supply pipe 48 through the supply pipe 48 to the cavity 87B and through the hole in the outermost peripheral wall 86B. Thus, the outer peripheral wall 86B is jetted from the outer peripheral surface 84B toward the inner peripheral surface of the melt F.

The porous material constituting the outermost peripheral wall 86B, the thickness of the outermost peripheral wall 86B, and the like are the same as those of the outermost peripheral wall 36 of the cooling member 32.
Further, other configurations such as a mechanism for cooling the cooling member 82 are the same as those of the cooling device 30.

In the present embodiment, when the melt F extruded in a tubular shape from the outlet hole 23 of the base 20 is cooled by the cooling device 80, the melt F surrounds the first region 82 </ b> A of the cooling member 82. After passing, it passes around the second region 82B.
Therefore, the melt F is first cooled while passing around the first region 82A having no porosity on the outer peripheral surface 84A, and the melt is cured in a state where the inner peripheral surface of the melt F follows the shape of the outer peripheral surface 84A. Progresses. Thereafter, the melt F that has been cured passes around the second region 82B having a porosity on the outer peripheral surface 84B, receives the pressurized medium ejected from the pores on the outer peripheral surface 84B, and spreads the inner surface. While being subjected to pressure in the direction in which it is pressed, it is further cooled and hardening further proceeds to form a tubular body T.
That is, although the melt F that has passed through the first region 82A and before passing through the second region 82B is hardened more than the melt F extruded from the outlet hole 23 of the base 20, for example. , It is not completely solidified (semi-cured state). Then, the cured body F passes through the second region 82 </ b> B, so that the curing further proceeds and the tubular body T is obtained.

In the present embodiment, as described above, the cooling member 82 is composed of the first region 82A having no porosity on the outer peripheral surface 84A and the second region 82B having porosity on the outer peripheral surface 84B. Further, the tubular body T having a smaller “swell” is obtained.
The reason for this is that since the pressure of the pressurized medium is applied after the effect of the melt F has progressed, the shape of the melt F is less affected by the pressure and the like, and the cooling member 82 is less porous than the case where there is no porosity. This is presumably because the frictional force between the outer peripheral surface 84B and the inner peripheral surface of the melt F is reduced.

  That is, when the softened melt F before being cured does not receive pressure from the pressurized medium, the shape of the inner peripheral surface of the melt F is fixed along the outer peripheral surface 84A, and thus the cure proceeds. It is considered that the shape of the melt F can be controlled more easily than when pressure is applied from the front. And, since the melt F is subjected to pressure by the pressurizing medium after the shape is fixed by the progress of curing, the change in the shape of the melt F due to the pressure hardly occurs, for example, even if there is a variation in the pressure, It is considered that the shape of the melt F is easily maintained. In addition, since the pressurized medium is ejected from the perforation of the outer peripheral surface 84B toward the inner peripheral surface of the melt F and receives a force in the direction in which the inner peripheral surface of the melt F is expanded, the puller 50 applies a tubular body. Even if T is pulled out, it is considered that distortion due to excessive tension hardly occurs.

In the present embodiment, the ratio of the length of the first region 82A to the length of the second region 82B is not particularly limited. For example, the length in the extrusion direction of the first region 82A is the same as the length of the second region 82B. The range which is 0.1 times or more and 2 times or less of the length of an extrusion direction is mentioned, It is desirable that it is 0.5 times or more and 1 time or less.
In the present embodiment, the cooling member 82 includes the first region 82A and the second region 82B. However, the cooling member 82 is not limited to this, and the outer periphery is further downstream in the extrusion direction than the second region 82B. It may be a form including a third region having no porosity on the surface.

In the cooling member 82 of the present embodiment, the outermost peripheral wall 86B of the second region 82B is made of a porous material. However, the present invention is not limited to this. For example, like the cooling member 62 shown in FIG. The form using the perforated plate which provided many through-holes as the outermost peripheral wall 86B of the 2nd area | region 82B may be sufficient.
Furthermore, in this embodiment, one cooling member 82 has the first region 82A and the second region 82B. However, the present invention is not limited to this. The second cooling member may be provided on the downstream side in the extrusion direction from the first cooling member, and may have a porosity on at least a part of the outer peripheral surface.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited only to the following examples. In the following, “part” and “%” are based on mass unless otherwise specified.

[Production of resin pellets]
<Resin pellet 1>
100 parts of polyphenylene sulfide (Torelina T1881, manufactured by Toray Industries, Inc., Tg: 85 ° C.) as a thermoplastic resin and 14 parts of carbon black (Monarch 880, manufactured by Cabot) as a conductive agent, Henschel mixer (FM10C manufactured by Nippon Coke) And mixed. The obtained mixture was melt-kneaded at 360 ° C. with a twin-screw extrusion melt kneader (L / D60 (manufactured by Parker Corporation)), extruded into a string shape through a hole of φ5, placed in a water tank, cooled, solidified and cut. Resin pellet 1 was obtained.

[Manufacture of tubular bodies]
<Manufacture of endless belt 1 (tubular body)>
A tubular body was manufactured by the tubular body manufacturing apparatus shown in FIG. 1 using the resin pellet 1 obtained by the production of the resin pellet.
Specifically, the resin pellet 1 is put into a uniaxial melting extruder (melting extrusion apparatus, manufactured by Mitsuba Seisakusho, model number: E-8001, L / D24) in which the extrusion temperature is set to 300 ° C. Extruded into a cylindrical shape from the gap (exit hole) between the die (die) and the nipple.

Next, in order to fix the cylindrical shape and diameter of the film while pulling out the extruded cylindrical film (melt F) by the drawer 50, the periphery of the cooling member 32 (sizing die) in the cooling device 30 Was passed.
Then, after the cylindrical film was cooled by the cooling device 30 and pulled out by the drawer 50, it was cut to a desired width to obtain an endless belt 1 having a diameter of 160 mm (inner diameter of 160 mm), a length of 232 mm, and a film thickness of 100 μm. .

The details of the cooling member 32 are as follows.
-Overall shape: cylindrical shape with an outer diameter of 160 mm and a length in the extrusion direction of 50 mm-Porous material constituting the outermost peripheral wall 36: a sintered body obtained by sintering bronze sphere powder-Thickness of the outermost peripheral wall 36: 5mm
-Average diameter of pores constituting the pore: 5 μm
・ Aperture ratio of the pores constituting the pore: 30%

In addition, an ethylene glycol aqueous solution (brine) was used as a coolant for cooling the cooling member 32, and air was used as a pressurizing medium ejected from the pores in the outer peripheral surface 34 of the cooling member 32.
The temperature of the refrigerant and the pressure and temperature of the pressurized medium were set as shown in Table 1.

<Manufacture of endless belts 2 to 3 (tubular body)>
Endless belts 2 to 3 were obtained in the same manner as the endless belt 1 except that the cooling device 80 shown in FIG. 4 was used instead of the cooling device 30 shown in FIG.

In addition, the detail of the cooling member 82 in the used cooling device 80 is as follows.
-Overall shape: cylindrical shape with an outer diameter of 160 mm and a length in the extrusion direction of 50 mm-Length in the extrusion direction in the first region 82A: 25 mm
-Length in the extrusion direction in the second region 82B: 25 mm
-Porous material constituting the outermost peripheral wall 86B of the second region 82B: a sintered body obtained by sintering bronze sphere powder-Thickness of the outermost peripheral wall 86B: 5 mm
-Average diameter of pores constituting the pore: 5 μm
-Opening ratio of the holes constituting the porosity in the outer peripheral surface 84B of the second region 82B: 30%

<Manufacture of endless belts 4 to 5 (tubular body)>
Endless belts 4 to 5 were obtained in the same manner as the endless belt 1 except that a cooling device having no porosity on the outer peripheral surface of the cooling member was used instead of the cooling device 30 shown in FIG.
The overall shape of the cooling member in the cooling device used was a cylindrical shape having an outer diameter of 160 mm and a length in the extrusion direction of 50 mm, and the temperature of the refrigerant was set as shown in Table 1.

[Evaluation of tubular body]
<Measurement of swell (Wmax)>
Using a surface roughness meter, measurement was performed at a measurement length of 50 mm, a cutoff wavelength of 0.8 mm, and a measurement speed of 0.6 mm / second. The measurement was performed at three locations in the width direction of the endless belt, and the average value was defined as waviness (Wmax). The results are shown in Table 1.

The evaluation criteria for waviness (Wmax) are as follows.
G1: Swell is 0.1 μm or less G2: Swell is greater than 0.1 μm and 0.2 μm or less G3: Swell is greater than 0.2 μm

<Measurement of axial straightness when stretching with two axes>
Two metal rolls having an outer diameter φ of 28 are placed in the obtained endless belt, the metal roll on one side is fixed, and the remaining one side is supported with a tension of 39.2 N while taking care not to bias the tension.
The position of the belt surface (outer peripheral surface) in the central portion between the two metal rolls was measured in the axial direction using a laser displacement meter, and the difference between the maximum value and the minimum value was determined. This measurement was performed at eight locations in the circumferential direction of the belt, and the maximum value of the difference was defined as the straightness in the axial direction during stretching with two axes. The results are shown in Table 1.

The evaluation criteria of the straightness in the axial direction when stretching with two axes are as follows.
G1: Axial straightness when stretching with two axes is 1.0 mm or less G2: Axial straightness when stretching with two axes is greater than 1.0 mm and 2.0 mm or less G3: When stretching with two axes Axial straightness greater than 2.0mm

<Evaluation of transferability>
The obtained endless belt is incorporated as an intermediate transfer belt of an image forming apparatus (DocuPrint CP200W manufactured by Fuji Xerox Co., Ltd.), and a halftone image (an image on which magenta is 40%) is A4 in an environment of a temperature of 22 ° C. and a humidity of 55% RH. Three sheets of vertical paper were output, and transferability was judged visually by the following evaluation criteria. The results are shown in Table 1.

-Evaluation criteria-
G1: No density unevenness in image G2: Light density unevenness in image G3: Density unevenness in image G4: Image missing

<Evaluation of variation in electrical resistance value>
A measuring device having an inner cylinder φ16 and an outer cylinder φ30 × φ40 with a double cylinder probe and an insulating bottom surface was used. The current value (5 seconds after voltage application) flowing in the outer cylinder when 100 V was applied to the inner cylinder of this device was measured, and the surface resistivity of the film (tubular body) was determined by calculation and converted to a common logarithm. This measurement was performed at 12 locations in the circumferential direction of the tubular body and at 3 locations in the axial direction, and the difference between the maximum value and the minimum value was determined. The results are shown in Table 1.

-Evaluation criteria-
G1: 0.2 log (Ω / □) or less G2: greater than 0.2 log (Ω / □) and less than 0.8 log (Ω / □) G3: 0.8 log (Ω / □) or more

  From the results of Table 1 above, it was found that an endless belt having excellent shape accuracy was obtained in the example, with a lower value of axial straightness during undulation and biaxial tension than in the comparative example. Further, it was found that the transferability was better in the example than in the comparative example.

DESCRIPTION OF SYMBOLS 10 Single screw extruder 11 Input port 12 Heating cylinder 13 Screw 20 Base 22 Flow path 23 Outlet hole 30, 60, 80 Cooling device 32, 62, 82 Cooling member 34, 64, 84A, 84B Outer peripheral surface 36, 66, 86A, 86B Outermost peripheral wall 38, 68, 88 Boundary wall 37, 42, 67, 87B Cavity 44, 48 Supply pipe 46 Discharge pipe 50 Drawer (drawer device)
52 Inner roll 54 Outer roll 70 Support member 82A First region 82B Second region 100 Tubular body manufacturing apparatus 110 Extruder F Melt P Resin material T Tubular body

Claims (5)

A cooling member that has a porosity in at least a part of the outer peripheral surface, and cools a tubular melt containing a molten thermoplastic resin extruded from a die provided in an extrusion device from the inner peripheral surface side of the melt;
A mechanism for ejecting a pressurized medium that is a gas from the porous toward the inner peripheral surface of the melt;
A mechanism for supplying a coolant, which is a medium different from the pressurized medium, to the cooling member, and cooling the cooling member;
With cooling device.   The cooling device according to claim 1, wherein the refrigerant is a liquid. The cooling member is located on the most upstream side in the extrusion direction of the melt and has a first region that does not have the porosity on the outer peripheral surface, and on the downstream side in the extrusion direction of the melt from the first region. The cooling device according to claim 1, further comprising: a second region that is located and has the porosity on an outer peripheral surface thereof. The cooling device according to any one of claims 1 to 3 , wherein a temperature of the pressurized medium is lower than a temperature of the refrigerant . An extrusion apparatus for extruding a melt containing a molten thermoplastic resin into a tubular shape from a die;
The cooling device according to any one of claims 1 to 4 , wherein the melt extruded in a tubular shape from the base is cooled from the inner peripheral surface side of the melt to form a tubular body.
A drawing device for pulling out the tubular body in the extrusion direction of the melt;
An apparatus for manufacturing a tubular body.