JP2012086528A - Method and apparatus for manufacturing seamless belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively manufacture a high quality seamless belt by continuously and stably discharging a melted body while suppressing mixing of air bubbles into the melted body of a resin composition, backflow of the melted body during the extrusion, and attachment of the melted body to a piston.SOLUTION: A method for manufacturing the seamless belt includes steps of: throwing a pellet made of the resin composition in an annular flow path having the melted body of the resin composition; melting the pellet by pressing the pellet thrown in the annular flow path and pushing the pellet in the melted body by a pressing surface contacting with the resin composition in the annular flow path using a piston whose temperature is adjusted to a temperature less than a melting point of the resin composition, and discharging the melted body from an annular die in the radial direction; adhering the discharged melted body to a part of a cylinder; relatively moving the cylinder and the annular die in the axial direction and applying the melted body to a wall surface of the cylinder in a state with the melted body adhered to the part of the cylinder to form a cylindrical layer of the melted body; and solidifying the cylindrical layer.

Description

  The present invention relates to a seamless belt manufacturing method and a manufacturing apparatus thereof.

  Patent Document 1 discloses a method for manufacturing a seamless belt used for an intermediate transfer belt, a transfer conveyance belt, and the like in an electrophotographic image forming apparatus such as a laser beam printer or a copying machine. In the manufacturing method disclosed in Patent Document 1, a thermosetting resin resin solution is extruded from the bottom of the inner wall of the cylindrical mold to the upper part in order from the extruded cylindrical mold inscribed in the cylindrical mold. Form a layer of solution. At this time, a seamless belt can be obtained by injecting gas into the resin solution layer to expand the resin solution layer and then curing the resin solution layer. Patent Document 1 describes that according to this manufacturing method, it is possible to apply a resin solution to the inner wall of a cylindrical mold in a short time, and to suppress the occurrence of application stripes, undulations, and resin solution residue. Yes.

JP 2004-237695 A

  In recent years, electrophotographic image apparatuses have been improved in image quality and price, and demands for the quality and price of seamless belts are increasing. Therefore, the present inventors apply the production method described in Patent Document 1 to the production of a seamless belt mainly composed of a thermoplastic resin that does not require a curing reaction process and is cheaper than a thermosetting resin. investigated. As a result, the following issues were found. That is, in the manufacturing method described in Patent Document 1, a resin solution layer is formed by allowing a resin solution to flow down to the bottom surface of a cylindrical mold. At this time, if the temperature of the cylindrical mold is lower than the melting point of the thermoplastic resin, the resin melt containing the thermoplastic resin starts to solidify when it touches the inner wall of the cylindrical mold. Therefore, the adhesiveness between the resin melt and the bottom surface of the cylindrical mold may be insufficient. Therefore, when gas is injected from the injection port provided on the bottom surface of the cylindrical mold, the gas may enter from the gap between the bottom surface of the cylindrical mold and the resin melt layer. In this case, the adhesion of the resin melt layer to the inner wall of the cylindrical mold may be prevented, and the surface roughness of the inner wall of the cylindrical mold may not be reliably transferred to the outer surface of the resin melt layer. . Therefore, the present invention is intended to provide a seamless belt manufacturing method and a manufacturing apparatus capable of manufacturing a high-quality seamless belt mainly composed of a thermoplastic resin at a low cost.

According to the present invention, a cylinder and a melt of a resin composition that is disposed coaxially with the cylinder, is relatively movable in the axial direction in the vicinity of the wall surface of the cylinder, and includes a thermoplastic resin. A method of manufacturing a seamless belt using a seamless belt manufacturing apparatus comprising an annular die capable of discharging in a radial direction,
The annular die has an inlet for pellets made of the resin composition, and an annular channel for melting the pellets introduced from the inlet, and the resin composition melted in the annular channel An annular piston for applying pressure to the melt and discharging the melt from the annular die, and the method for producing the seamless belt includes:
(1) charging the pellet made of the resin composition into the annular channel having the melt of the resin composition;
(2) The pressure of the pressure surface in contact with the resin composition in the annular channel is adjusted to a temperature lower than the melting point of the resin composition, and the pellet put in the annular channel is pressed to melt Melting the pellet by pushing the pellet into the body, and discharging the melt from the annular die in a radial direction;
(3) a step of bringing the discharged melt into close contact with a part of the cylinder;
(4) With the melt in close contact with a part of the cylinder, the cylinder and the annular die are moved relative to each other in the axial direction, and the melt is applied to the wall surface of the cylinder. Forming a cylindrical layer;
(5) A method for producing a seamless belt comprising the step of solidifying the cylindrical layer.

In addition, according to the present invention, a cylinder and a resin composition that is disposed coaxially with the cylinder, is relatively movable in the axial direction near the wall surface of the cylinder, and includes a thermoplastic resin. An apparatus for producing a seamless belt comprising an annular die capable of discharging a body in a radial direction,
The annular die has an inlet for pellets made of the resin composition, an annular channel for melting the pellets introduced from the inlet, and melting of the resin composition melted in the annular channel An apparatus for manufacturing a seamless belt is provided that includes an annular piston for applying pressure to a body to discharge the melt from the annular die.

  ADVANTAGE OF THE INVENTION According to this invention, the high quality seamless belt which has a thermoplastic resin as a main component can be manufactured at low cost.

It is sectional drawing of the manufacturing apparatus of the seamless belt which concerns on this invention. It is explanatory drawing of each process in the manufacturing method of the seamless belt which concerns on this invention. It is sectional drawing which shows one Embodiment of the manufacturing apparatus of the seamless belt of this invention. It is explanatory drawing of each process in the manufacturing method of the seamless belt which concerns on this invention.

  A seamless belt manufacturing apparatus according to the present invention includes a cylinder, a resin composition that is disposed coaxially with the cylinder, is movable in the axial direction in the vicinity of the wall surface of the cylinder, and includes a thermoplastic resin. An annular die capable of discharging a melt of the object in the radial direction. The annular die includes a pellet inlet made of the resin composition, an annular flow channel for melting the charged pellet made of the resin composition, and a melt of the resin composition melted in the annular flow channel And an annular piston that discharges the melt from the annular die. The apparatus may further include an adhesion means for bringing the melt discharged from the annular die into close contact with a part of the cylinder. According to this manufacturing apparatus, a high-quality seamless belt can be manufactured stably.

  FIG. 1 is a cross-sectional view showing an embodiment (first embodiment) of a seamless belt manufacturing apparatus according to the present invention. The manufacturing apparatus 100 of this embodiment includes a cylindrical mold 4 (cylinder), a gripping member 7 (contacting means), and an annular die 2. The cylindrical mold 4 has an upper end opened and a lower end supported by the stage 6. The stage 6 is supported by a guide 5 that extends in the vertical direction. The stage 6 moves along the guide 5. Thereby, the cylindrical mold 4 can be moved up and down. Above the cylindrical mold 4, the gripping member 7 is disposed in a state supported by the guide 5, and is opposed to the upper end opening of the cylindrical mold 4. The holding member 7 can be moved up and down along the guide 5.

  The annular die 2 is arranged on the coaxial outer side of the cylindrical mold 4 while being supported by the heat insulating base 9. The annular die 2 can melt a resin composition containing a thermoplastic resin with a heater (not shown). The annular die 2 has an annular discharge port 2b through which the melt 30 of the resin composition can be discharged radially inward. An annular channel 2a in which the pellet and the melt 30 are mixed is provided upstream of the discharge port 2b. Further, a pellet inlet 2c is arranged upstream. The piston 3 has an annular pressing surface 3 a at one end and is incorporated in the annular flow path 2 a of the annular die 2. The other end protrudes to the upper part of the annular die 2 and is supported by the guide 5, and can move up and down in the annular flow path 2a. By pushing the piston 3, the pellets injected into the annular flow path 2 a are pressed and the pellets are pushed into the melt 30 to melt the pellets, and the melt 30 is discharged in the radial direction from the discharge port 2 b. Can do. The pressure surface 3a of the piston 3 can be adjusted to a temperature below the melting point of the resin composition by a cooling means (not shown). The radial direction includes both a direction from a certain point on the circumference toward the center (inside in the radial direction) and a direction from the center toward a certain point on the circumference (outside in the radial direction). The annular die in the present invention can discharge the melt 30 to at least one of the radially inner side and the outer side.

The seamless belt manufacturing method according to the present invention is a method for manufacturing a seamless belt using the seamless belt manufacturing apparatus, and includes the following steps (1) to (5).
(1) A step of introducing pellets made of the resin composition into the annular flow path having the melt of the resin composition.
(2) The pressure of the pressure surface in contact with the resin composition in the annular channel is adjusted to a temperature lower than the melting point of the resin composition, and the pellet put in the annular channel is pressed to melt The pellet is melted by pushing it into the body. At the same time, a step of discharging the melt from the annular die in the radial direction.
(3) A step of bringing the discharged melt into close contact with a part of the cylinder.
(4) With the melt in close contact with a part of the cylinder, the cylinder and the annular die are moved relative to each other in the axial direction, and the melt is applied to the wall surface of the cylinder. A step of forming a cylindrical layer.
(5) A step of solidifying the cylindrical layer.

  Hereinafter, an embodiment (first embodiment) of a method for producing a seamless belt according to the present invention will be described with reference to FIG. In the present embodiment, the above-described manufacturing apparatus 100 shown in FIG. 1 is used.

  In step (1), the piston 3 is pushed up until the annular flow path 2a and the inlet 2c communicate with each other, and pellets made of a resin composition containing a thermoplastic resin are introduced from the inlet 2c (see FIG. 2 (a)). . In the flow path 2a, the melt 30 of the resin composition remains downstream from the descending end of the annular pressing surface 3a. The pellets input from the input port 2c are temporarily deposited on the melt 30 remaining in the flow path 2a.

  In the present invention, it is preferable that the manufacturing apparatus 100 includes a weighing unit that measures the mass of the pellets, and the pellets weighed to a constant mass by the weighing unit are loaded from the loading port 2c. In particular, it is more preferable to measure and throw in as many pellets as the mass to be discharged in a series of steps. By making the amount of pellets charged constant when the series of steps is repeated, the amount and characteristics of the discharged melt 30 can be stabilized, and the seamless belt can be manufactured at a lower cost.

  In step (2), the pellets charged in the piston 3 are pressed. At the time when the pellets are charged, there is a gap between the pellets, but by pressing the pellets with the piston 3, the pellets are buried in the melt 30 in order from the descending end side of the annular pressing surface 3a. . This eliminates voids between the pellets and pushes the pellets into the melt 30. In this state, heat from a heater (not shown) is transmitted to the pellet through the annular die 2 and the melt 30, so that the pellet can be melted. When pressure is further applied while the pellets are buried in the melt 30, the melt 30 flows backward and tends to flow into the gap between the piston 3 and the flow path 2a. In the present embodiment, the pressure surface 3a of the piston 3 is adjusted to a temperature below the melting point of the resin composition by a cooling means (not shown). As a result, the melt 30 touching the pressing surface 3a starts to solidify, preventing the melt 30 from flowing into the gap between the piston 3 and the flow path 2a, and preventing the melt 30 from sticking to the pressing surface 3a. It is possible to stably pressurize the mixture 40 of pellets and melt.

  When the internal pressure of the flow path 2a is increased, the discharge port 2b of the annular die 2 with respect to the gap 20 (see FIG. 2A) provided between the upper end opening of the cylindrical mold 4 and the gripping member 7 is used. The melt 30 is discharged radially inward. As shown in FIG. 2A, the cylindrical mold 4 and the gripping member 7 are disposed at a position where the discharge port 2b of the annular die 2 and the gap 20 have the same height. Since the flow path 2a of the annular die 2 has no flow branching and joining points, and the piston 3 has an annular pressing surface 3a, a line generated by discontinuity of the flow when the cylindrical layer 1 is formed. It is possible to avoid the occurrence of so-called weld lines. Furthermore, since the flow path 2a can have an axisymmetric shape, the pressure and flow velocity distribution are uniform over the entire circumference. As a result, the melt 30 is uniformly discharged from the discharge port 2b, and a seamless belt with uniform strength and thickness can be manufactured. The discharge direction of the melt 30 is preferably a horizontal direction, but may be an elevation angle direction or a depression angle direction.

  In step (3), as shown in FIG. 2 (b), the holding member 7 is lowered and the melt 30 pushed into the gap 20 is sandwiched between the cylindrical mold 4 and the holding member 7. As a result, the melt 30 is brought into close contact with the upper end surface of the cylindrical mold 4. In this step, when the melt 30 is sandwiched between the cylindrical mold 4 and the gripping member 7, the cylindrical mold 4 may be raised. Alternatively, the cylindrical mold 4 may be raised and the gripping member 7 may be lowered. That is, at least one selected from the cylindrical mold 4 and the gripping member 7 is moved in a direction approaching each other, and the melt 30 is sandwiched between the cylindrical mold 4 and the gripping member 7. In this embodiment, the melt 30 is held in close contact with a part of the cylindrical mold 4 by sandwiching the melt 30 between the cylindrical mold 4 and the gripping member 7, but the gripping member 7 is not used. The melt 30 may be adhered to a part of the cylindrical mold 4 by a method. For example, a method of sucking and adhering the melt 30 with a part of the cylindrical mold 4 may be used, or a method of providing a space in a part of the cylindrical mold 4 and injecting and adhering the melt 30 may be used. In any case, it is sufficient that the melt 30 can be in close contact with a part of the cylindrical mold 4 when the layer is formed in the step (4) described later.

  In the step (4), the state in which the melt 30 is sandwiched between the cylindrical mold 4 and the gripping member 7, that is, the state in which the melt 30 is in close contact with a part of the cylindrical mold 4 is maintained. In this state, the piston 3 is further pushed down at a desired speed to continuously discharge the melt 30 from the annular die 2 radially inward, while the cylindrical die 4 and the gripping member 7 are moved against the annular die 2. Raise. Thus, the melt 30 is continuously applied to the outer wall surface of the cylindrical mold 4 to form the cylindrical layer 1 on the outer wall surface of the cylindrical mold 4 (see FIG. 2C). The speed at which the piston 3 is pushed down corresponds to the outflow speed of the melt 30 from the discharge port 2b, and the thickness of the cylindrical layer 1 is controlled by controlling the outflow speed and the rising speed of the cylindrical mold 4. can do. Furthermore, when forming the cylindrical layer 1, the annular die 2 may be lowered with respect to the cylindrical mold 4 and the holding member 7. Alternatively, the cylindrical die 4 and the holding member 7 may be raised and the annular die 2 may be lowered. That is, the cylindrical layer 1 may be formed on the outer wall surface of the cylindrical mold 4 by relatively moving the cylindrical mold 4 and the gripping member 7 and the annular die 2 in the axial direction.

  In the step (5), the cylindrical layer 1 is solidified in a state where it is formed on the outer wall surface of the cylindrical mold 4. At this time, it is preferable to adjust the temperature of the cylindrical mold 4 to a range not lower than the glass transition point of the resin composition and lower than the melting point of the resin composition. By setting the temperature of the cylindrical mold 4 within the temperature range, the cylindrical layer 1 is gradually cooled while being in contact with the outer wall surface of the cylindrical mold 4, so that the degree of crystallinity is increased and the strength is increased. Can be increased. Alternatively, the cylindrical mold 4 can be set to a temperature lower than the glass transition point of the resin composition. In this case, the cylindrical layer 1 starts to solidify as soon as it adheres to the cylindrical mold 4. Since the cylindrical layer 1 is rapidly cooled, it solidifies without progressing crystallization, and a highly flexible seamless belt is obtained. The temperature control of the cylindrical mold 4 can be performed by a temperature sensor (not shown), a heater and a cooler (not shown) that can be controlled based on the detection result of the temperature sensor.

  Thereafter, the solidified product of the cylindrical layer 1 formed on the outer wall surface of the cylindrical mold 4 is taken out. Specifically, the holding member 7 is raised with respect to the cylindrical mold 4, and the holding member 7 and the cylindrical mold 4 are separated. After the cylindrical layer 1 is sufficiently solidified, the solidified product of the cylindrical layer 1 is taken out from the cylindrical mold 4 by using unillustrated taking-out means. Then, a seamless belt is obtained by cutting off both ends of the solidified product of the cylindrical layer 1 taken out. In the method according to the embodiment, it is possible to manufacture a seamless belt with no wall bubbles and high thickness accuracy and shape accuracy at low cost.

  In this embodiment, the cylindrical layer 1 is formed on the outer wall surface of the cylindrical mold 4, but the cylindrical layer 1 may be formed on the inner wall surface of the cylindrical mold 4. In this case, the annular die 2 is disposed on the coaxially inner side of the cylindrical mold 4, and the melt 30 is extruded radially outward from the discharge port 2 b of the annular die 2, and is cylindrical on the inner wall surface of the cylindrical mold 4. Layer 1 is formed continuously.

  FIG. 3 is a cross-sectional view showing an embodiment (second embodiment) of a seamless belt manufacturing apparatus according to the present invention. The manufacturing apparatus 101 of the present embodiment includes a cylindrical mold 4 (cylinder), a gripping member 7 (contacting means), and an annular die 2. The cylindrical mold 4 has an upper end opened and a lower end supported by the stage 6. The stage 6 is supported by a guide 5 that extends in the vertical direction. The stage 6 moves along the guide 5. Thereby, the cylindrical mold 4 can be moved up and down. Above the cylindrical mold 4, the gripping member 7 is disposed in a state supported by the guide 5, and is opposed to the upper end opening of the cylindrical mold 4. The holding member 7 can be moved up and down along the guide 5. An inlet 8 is provided on the upper bottom of the gripping member 7. The injection port 8 is connected to a gas injection means (not shown), and gas can be introduced into the gripping member 7 through the injection port 8.

  The annular die 2 is disposed on the coaxial inner side of the cylindrical mold 4 while being supported by the heat insulating base 9. The annular die 2 can melt a resin composition containing a thermoplastic resin with a heater (not shown). Further, the annular die 2 has an annular discharge port 2b through which the melt 30 of the resin composition can be discharged in the radial direction. An annular channel 2a in which the pellet and the melt 30 are mixed is provided upstream of the discharge port 2b. Further, a pellet inlet 2c is arranged upstream. The piston 3 has an annular pressing surface 3 a at one end and is incorporated in the annular flow path 2 a of the annular die 2. The other end protrudes to the upper part of the annular die 2 and is directed to the guide 5, and can be moved up and down in the annular flow path 2a by an actuator (not shown). The pressure surface 3a of the piston 3 can be adjusted to a temperature below the melting point of the resin composition by a cooling means (not shown). The radial direction indicates a direction from the center toward a certain point on the circumference (outside in the radial direction).

The seamless belt manufacturing method according to the present invention is a method for manufacturing a seamless belt using the seamless belt manufacturing apparatus, and includes the following steps (1) to (6).
(1) A step of introducing pellets made of the resin composition into the annular flow path having the melt of the resin composition.
(2) The pressure of the pressure surface in contact with the resin composition in the annular channel is adjusted to a temperature lower than the melting point of the resin composition, and the pellet put in the annular channel is pressed to melt The pellet is melted by pushing it into the body. At the same time, a step of discharging the melt from the annular die in the radial direction.
(3) A step of bringing the discharged melt into close contact with a part of the cylinder by close contact means and blocking communication of gas at the close contact portion.
(4) In a state where the melt is brought into close contact with a part of the cylinder by the contact means, the cylinder, the contact means and the annular die are moved relative to each other in the axial direction to melt the melt onto the inner wall surface of the cylinder. Applying a body to form a cylindrical layer of the melt.
(5) A step of introducing a gas into a space formed by the contact means, the cylindrical layer, and the annular die, and bringing the cylindrical layer into close contact with the inner wall surface of the cylinder by the pressure of the gas.
(6) A step of solidifying the cylindrical layer.

  Hereinafter, an embodiment (second embodiment) of a method for producing a seamless belt according to the present invention will be described with reference to FIG. In the present embodiment, the above-described manufacturing apparatus 101 shown in FIG. 3 is used.

  Steps (1) and (2) can be performed in the same manner as steps (1) and (2) of the first embodiment, respectively, except that the direction in which the melt 30 is discharged is the radial direction. (See FIG. 4 (a)).

  In step (3), as shown in FIG. 4B, the holding member 7 is lowered and the melt 30 discharged into the gap 20 is sandwiched between the cylindrical mold 4 and the holding member 7. As a result, the melt 30 is brought into close contact with the upper end surface of the cylindrical mold 4, and gas communication at the close contact portion is blocked. The space formed by the gripping member 7, the cylindrical layer 1, and the annular die 2 in the step (5) to be described later is made a sealed space by sufficiently bringing the melt 30 into close contact and shutting off the gas communication in the contact portion. When the gas is introduced into the space, the internal pressure can be increased. The close contact portion indicates a contact portion between the cylindrical mold 4 and the melt 30 and a contact portion between the gripping member 7 and the melt 30. When the melt 30 is sandwiched between the cylindrical mold 4 and the gripping member 7, at least one selected from the cylindrical mold 4 and the gripping member 7 is attached to each other as in step (3) of the first embodiment. The melt 30 can be sandwiched between the cylindrical mold 4 and the gripping member 7 by moving in the approaching direction.

  In the step (4), the molten metal 30 is sandwiched and brought into close contact with the cylindrical mold 4 and the gripping member 7, and the state where the gas communication at the contact portion is blocked is maintained. From this state, the cylindrical die 4 and the gripping member 7 are raised with respect to the annular die 2 while the piston 3 is pushed down at a desired speed to continuously discharge the melt 30 from the annular die 2 in the radial direction. Let Thus, the melt 30 is continuously applied to the inner wall surface of the cylindrical mold 4 to form the cylindrical layer 1 on the inner wall surface of the cylindrical mold 4 (see FIG. 4C). In addition, about the control method of the thickness of the cylindrical layer 1, and the movement of the cylindrical die 4, the holding member 7, and the cyclic | annular die | dye 2, it is the same as that of the process (4) of 1st embodiment.

  In the step (5), gas is introduced into a space 50 formed by the gripping member 7, the cylindrical layer 1 and the annular die 2, and the cylindrical layer 1 is removed from the cylindrical mold 4 by the pressure of the gas. Close contact with the inner wall surface (see FIG. 4C). Specifically, following the step (4) or in parallel with the step (4), gas is injected into the space 50 from the gas injection means (not shown) through the injection port 8. At this time, since gas communication is blocked at the close contact portion, as shown in FIG. 4C, the space 50 partitioned by the gripping member 7, the cylindrical layer 1, and the annular die 2 is a sealed space. Only the inside of the space 50 is pressurized by gas injection. As a result, the cylindrical layer 1 is brought into close contact with the inner wall surface of the cylindrical mold 4. The gas injected from the inlet 8 is preferably an inert gas typified by air or nitrogen gas.

  About a process (6), it can carry out similarly to the process (5) of 1st embodiment except solidifying in the state which formed the cylindrical layer 1 in the inner wall face of the cylindrical metal mold | die 4. FIG.

  Thereafter, the solidified product of the cylindrical layer 1 formed on the inner wall surface of the cylindrical mold 4 is taken out. Specifically, after the cylindrical layer 1 is sufficiently solidified, the gas injection from the injection port 8 is stopped. Subsequently, the gripping member 7 is raised with respect to the cylindrical mold 4, and the gripping member 7 and the cylindrical mold 4 are separated. Thereafter, the solidified product of the cylindrical layer 1 is taken out from the cylindrical mold 4 using a taking-out means (not shown). Then, a seamless belt is obtained by cutting off both ends of the solidified product of the cylindrical layer 1 taken out.

  In the present embodiment, the gas communication in the close contact portion is blocked in the step (3), and the cylindrical layer 1 is continuously formed from the close contact portion in the step (4). Furthermore, only the inside of the space 50 is pressurized in the step (5). Therefore, gas does not enter the gap between the inner wall surface of the cylindrical mold 4 and the cylindrical layer 1 in the step (5). Therefore, the cylindrical layer 1 can be solidified in the step (6) while the cylindrical layer 1 is kept in close contact with the inner wall surface of the cylindrical mold 4. As a result, the surface of the inner wall of the cylindrical mold 4 is reliably transferred to the outer surface of the cylindrical layer 1. Furthermore, the outer diameter accuracy of the solidified product of the cylindrical layer 1 formed on the inner wall surface of the cylindrical mold 4 can be stabilized at the same level as the inner diameter accuracy of the cylindrical mold 4. As described above, in the method according to this embodiment, the surface of the inner wall of the cylindrical mold 4 is accurately transferred onto the surface of the seamless belt, and therefore a seamless belt with a uniform surface shape and less unevenness can be manufactured at low cost.

  In the present invention, the resin composition containing a thermoplastic resin is not particularly limited. However, when the use of the seamless belt is an electrophotographic apparatus, the following resins are preferable as the thermoplastic resin. Polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex component, ethylene / propylene copolymer rubber, styrene / butadiene rubber, styrene / butadiene・ Styrene block copolymer or its hydrogenated derivatives, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyphenylene ether, modified polyphenylene ether, polyimide, liquid crystalline polyester, polyethylene terephthalate, polysulfone, poly Ether sulfone, polyphenylene sulfide, polybisamide triazole, polybutylene terephthalate, polyether imide, polyether ether ketone , Acrylic, polyvinylidene fluoride, polyvinyl fluoride, ethylene tetrafluoroethylene copolymer, chlorotrifluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, acrylic, alkyl acrylate ester copolymer, Polyester ester copolymer, polyether ester copolymer, polyether amide copolymer, polyurethane copolymer. These may use only 1 type and may use 2 or more types together. In view of durability, the thermoplastic resins are preferably those classified into engineering plastics and super engineering plastics. Specifically, polyether ether ketone, polyethylene sulfide, polycarbonate, polyvinylidene fluoride, polyethylene terephthalate, and polyethylene naphthalate are more preferable.

  Further, when the use of the seamless belt is an electrophotographic apparatus, it is preferable to impart functions by dispersing various additives in the seamless belt according to the use. For example, when used for a transfer conveyance belt, an intermediate transfer belt or the like, it is preferable to disperse an inorganic additive particularly for the purpose of controlling resistivity. Examples of the inorganic additive include fine powders of carbon black, graphite, metal, and metal oxide. Examples of the metal include copper, tin, aluminum, and indium. Examples of the metal oxide include tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, and indium oxide doped with tin. As the inorganic additive, carbon black is preferable. Examples of the carbon black include acetylene black, “Ketjen black” (trade name, manufactured by Lion Corporation), furnace black, and channel black. Further, lubricating particles such as molybdenum disulfide may be added for the purpose of imparting slipperiness, and silicon dioxide and titanium oxide may be added for the purpose of improving the hardness.

  The seamless belt produced by the method according to the present invention can be used for an intermediate transfer belt, a transfer conveyance belt, a photosensitive belt, a fixing belt, and the like of an electrophotographic image forming apparatus (laser beam printer, copying machine, etc.).

Example 1
A seamless belt manufacturing apparatus having the configuration shown in FIG. 1 is used, and the electrophotographic seamless belt is taken along steps (1) to (5) (FIGS. 2 (a) to (c)) shown in the first embodiment. Manufactured.

  In the manufacturing apparatus shown in FIG. 1, the cylindrical mold 4 has an outer diameter of 290 mm and an axial length of 420 mm. The cylindrical mold 4 was controlled at 120 ° C. by a temperature control means (not shown). The holding member 7 had an outer diameter of 290 mm and an axial length of 250 mm. The inner diameter of the discharge port 2b of the annular die 2 was 295 mm. The flow path 2a and the inlet 2c of the annular die 2 are opened when the piston 3 reaches the rising end. The annular die 2 was controlled at 380 ° C. by a temperature control means (not shown).

As a preparation, acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) was mixed with polyether ether ketone (trade name: VICTREX PEEK, manufactured by Victrex). This was uniformly kneaded with a biaxial molding machine to produce a resin composition. The resin composition was molded into resin pellets. The volume resistivity of the resin pellet was 1 × 10 ^{10 to} 5 × 10 ¹⁰ Ωcm. The resin composition had a glass transition point of about 150 ° C. and a melting point of about 340 ° C.

  First, as shown in FIG. 2 (a), in the state where the melt of the resin composition exists downstream from the descending end of the piston 3 in the flow path 2a, the piston 3 is raised to the rising end, and the flow path 2a is inserted. The opening 2c was opened, and an appropriate amount of normal temperature pellets was charged into the flow path 2a from the charging port 2c (step (1)).

  Next, as shown in FIG. 2 (b), the piston 3 was lowered, and the pellet was buried in the melt and melted to obtain a mixture 40 of the pellet and the melt. At this time, the cylindrical mold 4 and the gripping member 7 are arranged such that a gap 20 of 10 mm exists between both ends of the cylindrical mold 4 and the gripping member 7. Further, the height is adjusted so that the position of the gap 20 and the position of the discharge port 2b of the annular die 2 substantially coincide. Further, the mixture 40 was pressurized by pushing down the piston 3, and the melt 30 was discharged from the discharge port 2b toward the gap 20 (step (2)). Thereafter, the gripping member 7 was lowered, and the melt 30 discharged into the gap 20 was sandwiched between the cylindrical mold 4 and the gripping member 7 (step (3)).

  Next, as shown in FIG. 2 (c), the cylindrical mold 4 is moved down at a rate of 0.2 mm / second while the melt 30 is sandwiched between the cylindrical mold 4 and the gripping member 7. And the holding member 7 was raised at 15 mm / sec (process (4)). Thereby, the cylindrical layer 1 was formed on the outer wall surface of the cylindrical mold 4. At this time, the temperature of the cylindrical mold 4 was adjusted to 120 ° C., which is lower than the glass transition point of the resin composition, so that the melt 30 rapidly heated when pushed out onto the outer wall surface of the cylindrical mold 4. Was solidified without progressing crystallization to form a cylindrical layer 1 (step (5)). After the cylindrical layer 1 is formed over about 400 mm, the lowering of the piston 3 is stopped, and the cylindrical mold 4 and the gripping member 7 on which the cylindrical layer 1 is formed are further raised to continue from the discharge port 2b. The cylindrical layer 1 was cut. Next, the holding member 7 was separated from the cylindrical mold 4, and the cylindrical layer 1 was peeled off from the outer wall surface of the cylindrical mold 4. A seamless belt was obtained by cutting both ends of the peeled cylindrical layer 1.

  Even when the seamless belt was stretched between two parallel rollers, no distortion was observed, and a stable shape having a thickness of 100 μm was maintained. Further, since there is no branching or confluence in the flow path 2a, no weld line was generated, and uniform strength was exhibited over the entire surface of the seamless belt. In addition, the surface could be molded without any spots. Furthermore, since the temperature of the cylindrical mold 4 was controlled below the glass transition point, a highly flexible seamless belt was obtained.

(Example 2)
A seamless belt manufacturing apparatus having the configuration shown in FIG. 3 is used, and the electrophotographic seamless belt is taken along steps (1) to (6) (FIGS. 4A to 4C) shown in the second embodiment. Manufactured.

  In the manufacturing apparatus shown in FIG. 3, the cylindrical mold 4 has an inner diameter of 290 mm and an axial length of 420 mm. Further, the inner wall surface of the cylindrical mold 4 is subjected to a surface treatment so that the surface of the seamless belt has a predetermined surface roughness [ten-point average roughness (Rzjis, JIS K0601-2001): 0.4 μm]. It was given. The cylindrical mold 4 was controlled at 250 ° C. by a temperature control means (not shown). The inner diameter of the gripping means 7 was 290 mm, and the length in the axial direction was 250 mm. The outer diameter of the discharge port 2b of the annular die 2 was 282 mm. The flow path 2a and the inlet 2c of the annular die 2 are opened when the piston 3 reaches the rising end. The annular die 2 was controlled at 380 ° C. by a temperature control means (not shown).

  Pellets were prepared as in Example 1. As shown in FIG. 4A, in the state where the melt of the resin composition exists downstream from the descending end of the piston 3 in the channel 2a, the piston 3 is raised to the ascending end, and the channel 2a and the inlet are 2c was opened, and normal temperature pellets were introduced into the flow path 2a from the inlet 2c (step (1)). Note that the pellets were weighed and fed only for one discharge mass by a weighing means (not shown).

  Thereafter, the piston 3 was lowered, and the pellet was buried and melted in the melt, whereby a mixture 40 of the pellet and the melt was obtained. At this time, the cylindrical mold 4 and the gripping member 7 are arranged such that a gap 20 of 10 mm exists between both ends of the cylindrical mold 4 and the gripping member 7. Further, the height is adjusted so that the position of the gap 20 and the position of the discharge port 2b of the annular die 2 substantially coincide. Next, as shown in FIG. 4B, the mixture 40 was further pressurized by further pushing down the piston 3, and the melt 30 was discharged from the discharge port 2b toward the gap 20 (step (2)). Thereafter, the gripping member 7 was lowered, and the melt 30 discharged into the gap 20 was sandwiched between the cylindrical mold 4 and the gripping member 7 (step (3)). It should be noted that the gas flow is blocked at the close contact portion.

  Next, as shown in FIG. 4 (c), the cylindrical mold 4 is moved down at a rate of 0.2 mm / second while the melt 30 is sandwiched between the cylindrical mold 4 and the gripping member 7. And the holding member 7 was raised at 15 mm / sec (process (4)). At the same time, compressed air was injected into the space 50 from the inlet 8 of the gripping member 7 (step (5)). The space 50 is formed by the gripping member 7, the melt 30 (cylindrical layer 1), and the annular die 2. Thereby, the cylindrical layer 1 was formed on the inner wall surface of the cylindrical mold 4, and the cylindrical layer 1 was brought into close contact with the inner wall surface of the cylindrical mold 4. At this time, since the temperature of the cylindrical mold 4 was adjusted to 250 ° C., which is lower than the melting point of the resin composition, the melt 30 was gradually deprived of heat when it was extruded onto the inner wall surface of the cylindrical mold 4. Solidified into a cylindrical layer 1 (step (6)). After the cylindrical layer 1 is formed over about 400 mm, the lowering of the piston 3 is stopped, and the cylindrical mold 4 and the gripping member 7 on which the cylindrical layer 1 is formed are further raised to continue from the discharge port 2b. The cylindrical layer 1 was cut. Next, injection of compressed air was stopped, the gripping member 7 was separated from the cylindrical mold 4, and the cylindrical layer 1 was peeled from the inner wall surface of the cylindrical mold 4. A seamless belt was obtained by cutting both ends of the peeled cylindrical layer 1.

  Even when the seamless belt was stretched between two parallel rollers, no distortion was observed, and a stable shape having a thickness of 100 μm was maintained. Further, since there is no branching or confluence in the flow path 2a, no weld line was generated, and uniform strength was exhibited over the entire surface of the seamless belt. In addition, the surface could be molded without any spots. Since the temperature of the cylindrical mold 4 was controlled to the glass transition point or more and the melting point or less, a seamless belt having a crystallinity of 20% or more, high tensile strength, and high surface hardness was obtained. Furthermore, the outer surface of the seamless belt transferred the surface roughness of the inner wall surface of the cylindrical mold 4, and the ten-point average roughness was 0.4 μm.

DESCRIPTION OF SYMBOLS 1 Cylindrical layer 2 Annular die 4 Cylindrical metal mold 7 Gripping member 20 Gap 30 Melt 40 Mixture 50 Space

Claims (2)

A cylinder,
An annular die that is arranged coaxially with the cylinder, is relatively movable in the axial direction in the vicinity of the wall surface of the cylinder, and can discharge a melt of a resin composition containing a thermoplastic resin in a radial direction; A method for producing a seamless belt using a seamless belt production apparatus comprising:
The annular die is
An annular channel having a pellet inlet made of the resin composition, and melting the pellet charged from the inlet;
An annular piston for applying a pressure to the melt of the resin composition melted in the annular channel and discharging the melt from the annular die,
The method for producing the seamless belt is as follows:
(1) charging the pellet made of the resin composition into the annular channel having the melt of the resin composition;
(2) The pressure of the pressure surface in contact with the resin composition in the annular channel is adjusted to a temperature lower than the melting point of the resin composition, and the pellet put in the annular channel is pressed to melt Melting the pellet by pushing the pellet into the body, and discharging the melt from the annular die in a radial direction;
(3) a step of bringing the discharged melt into close contact with a part of the cylinder;
(4) With the melt in close contact with a part of the cylinder, the cylinder and the annular die are moved relative to each other in the axial direction, and the melt is applied to the wall surface of the cylinder. Forming a cylindrical layer;
(5) A method for producing a seamless belt, comprising: solidifying the cylindrical layer. A cylinder,
An annular die that is arranged coaxially with the cylinder, is relatively movable in the axial direction in the vicinity of the wall surface of the cylinder, and can discharge a melt of a resin composition containing a thermoplastic resin in a radial direction; A seamless belt manufacturing apparatus comprising:
The annular die is
An annular channel having a pellet inlet made of the resin composition, and melting the pellet charged from the inlet;
An annular piston for applying a pressure to the melt of the resin composition melted in the annular flow path and discharging the melt from the annular die. manufacturing device.

Images