JP2012051340A - Method and device for manufacturing seamless belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method that can manufacture a high quality seamless belt containing a thermoplastic resin as a primary content, at low cost.SOLUTION: The method for manufacturing a seamless belt includes the steps of: extruding a molten material 30 from an annular die 2; bringing a tip end of the extruded molten material 30 into close-contact with an adhesion device provided in a tubular metallic mold 4; relatively moving the tubular metallic mold 4 and the annular die 2 in an axial direction and applying the molten material 30 on the inner wall of the tubular metallic mold 4 to form a tubular layer 1, while bringing the tip end of the molten material 30 into close-contact with the adhesion device; filling a gas into an inner space 50 partitioned by the tubular layer 1, the annular die 2 and the tubular metallic mold 4, and bringing the tubular layer 1 into close-contact with the inner wall of the tubular metallic mold 4 by the pressure of the gas; and solidifying the tubular layer 1.

Description

  The present invention relates to a seamless belt manufacturing method and a manufacturing apparatus thereof. In particular, the present invention relates to a method for manufacturing a seamless belt used for an intermediate transfer belt, a transfer conveyance belt, a photosensitive belt, a fixing belt, and the like in an electrophotographic image forming apparatus (laser beam printer, copying machine, etc.) and a manufacturing apparatus therefor.

  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, the electrophotographic image apparatus has a high image quality and a low price, and the demand for the quality and price of the seamless belt is 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.

One aspect of a method for producing a seamless belt according to the present invention is a cylindrical mold, which is disposed coaxially with the cylindrical mold, and is close to the inner wall of the cylindrical mold, with respect to the cylindrical mold. A seamless belt using a seamless belt manufacturing apparatus comprising an annular die that is relatively movable in the axial direction and is capable of discharging a molten resin composition containing a thermoplastic resin in a radial direction. A method of manufacturing
(1) a first step of extruding the melt radially from the annular die;
(2) a second step in which the tip of the extruded melt is brought into close contact with the contact means provided in the cylindrical mold; and (3) the tip of the melt is brought into close contact with the contact means. In this state, the cylindrical mold and the annular die are moved relative to each other in the axial direction, and the melt is applied to the inner wall of the cylindrical mold to form a continuous cylindrical layer from the tip of the melt. A third step to form;
(4) Gas is filled in the internal space partitioned by the cylindrical layer, the cylindrical mold, and the annular die, and the cylindrical layer is attached to the inner wall of the cylindrical mold by the pressure of the gas. A fourth step of closely adhering to
(5) A fifth step of solidifying the cylindrical layer.

One aspect of the seamless belt manufacturing apparatus according to the present invention is as follows.
A cylindrical mold provided with a close contact means, and disposed coaxially with the cylindrical mold, and is movable in the axial direction relative to the cylindrical mold in the vicinity of the inner wall of the cylindrical mold. And an annular die capable of discharging a melt of a resin composition containing a thermoplastic resin in a radial direction.

  ADVANTAGE OF THE INVENTION According to this invention, the seamless belt which consists of a resin composition containing the thermoplastic resin excellent in surface property can be manufactured at low cost.

It is sectional drawing which shows one Embodiment of the manufacturing apparatus of the seamless belt of this invention. It is sectional drawing of a resin injection groove. It is sectional drawing of the adsorption pad comprised with a porous body. It is sectional drawing of the suction pad comprised by a slit and a manifold. It is sectional drawing of the contact | adherence means at the time of connecting a suction means to the resin injection groove. It is sectional drawing which shows the state of the manufacturing apparatus in each manufacturing process.

  FIG. 1 is a cross-sectional view showing an embodiment of the seamless belt manufacturing apparatus of the present invention. The manufacturing apparatus 100 of this embodiment has the cylindrical metal mold | die 4 and the cyclic | annular die | dye 2, as shown in FIG.

  An injection port 8 is provided at the upper end of the cylindrical mold 4. The injection port 8 is connected to a gas injection means (not shown) so that gas can be injected into the cylindrical mold 4 through the injection port 8. The lower end portion of the cylindrical mold 4 is 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 so that the cylindrical mold 4 can be raised and lowered.

  The cylindrical mold 4 has a resin injection groove 9 as a close contact means on a part of its wall surface. One form of the resin injection groove 9 is shown in FIG. The resin injection groove 9 shown in FIG. 2A extends in the radial direction from the inner wall of the cylindrical mold 4. As shown in FIG. 2B, the resin injection groove 9 may have a structure in which the tip protrudes toward the annular die 2 side. The resin injection groove 9 may be provided with a vent hole 9a for letting gas escape. That is, the resin injection groove 9 may penetrate from the inner wall to the outer wall of the cylindrical mold 4. Furthermore, it is preferable to provide a temperature control means for the resin injection groove 9.

  Inside the cylindrical mold 4, the annular die 2 is arranged in a state of being supported by the heat insulating base 7. The annular die 2 has an annular discharge port 2c through which a melt 30 of a resin composition containing a thermoplastic resin can be continuously discharged in the radial direction. The annular die 2 is provided with a pellet inlet 2a made of a thermoplastic resin composition. Further, the pellets introduced from the introduction port 2a are melted in the annular flow path 2b in the annular die 2 and discharged from the discharge port 2c in the radial direction. A piston 3 having an annular pressing surface 3 a that fits into the flow path 2 b of the annular die 2 is fitted into the flow path 2 b of the annular die 2. The piston 3 pressurizes the melt in the flow path 2b of the annular die 2 so as to be pushed out in the radial direction from the discharge port 2c. Since the flow path 2b of the annular die 2 has no branching and joining points, and the piston 3 includes the annular pressing surface 3a, the pressure and flow velocity distribution in each of the flow paths 2b become uniform. As a result, the melt is uniformly discharged from the discharge port 2c to the entire circumference of the inner wall of the cylindrical mold 4, so that a line generated by discontinuity of flow when forming the cylindrical layer, a so-called weld line is formed. Occurrence can be avoided. Therefore, it is possible to produce a seamless belt with uniform strength and thickness. The discharge direction of the melt is preferably a horizontal direction, but may be an elevation angle direction or a depression angle direction.

  Next, a method for manufacturing a seamless belt according to this embodiment will be described. The seamless belt manufacturing method according to the present embodiment uses a manufacturing apparatus 100 including a cylindrical mold 4 and an annular die 2. The annular die 2 is arranged coaxially with the cylindrical mold 4, is close to the inner wall of the cylindrical mold 4, is movable in the axial direction relative to the cylindrical mold 4, and The melt 30 of the resin composition containing a thermoplastic resin can be discharged in the radial direction. And the manufacturing method of the seamless belt which concerns on this embodiment has the process of following (1)-(5).

  Step (1) is a step of radially extruding the melt 30 from the annular die 2 onto the inner wall of the cylindrical mold 4.

  Step (2) is a step in which the tip of the melt 30 extruded on the inner wall of the cylindrical mold 4 is injected into the resin injection groove 9 and the tip of the melt 30 is brought into close contact with the resin injection groove 9.

  In the step (3), the cylindrical mold 4 and the annular die 2 are moved relative to each other in the axial direction in a state where the tip of the melt 30 is in close contact with the resin injection groove 9, and the inner wall of the cylindrical mold 4 is moved. In this process, the melt 30 is applied to form a continuous cylindrical layer 1 from the tip of the melt 30.

  In the step (4), a gas is filled in the internal space 50 partitioned by the cylindrical layer 1, the cylindrical mold 4, and the annular die 2, and the cylindrical layer 1 is removed from the cylindrical mold by the pressure of the gas. 4 is a step of closely contacting the inner wall of 4.

  Step (5) is a step of solidifying the cylindrical layer 1.

  FIGS. 6A to 6C are cross-sectional views showing the state of the manufacturing apparatus 100 in each of the steps (1) to (5).

  In step (1), a melt 30 of a resin composition containing a thermoplastic resin is discharged from the annular die 2 onto the inner wall of the cylindrical mold 4. As shown in FIG. 6A, the cylindrical mold 4 is disposed at a position where the discharge port 2c of the annular die 2 and the resin injection groove 9 are at the same height. Further, the piston 3 is pushed up to a height that can secure a space for feeding pellets of the thermoplastic resin composition. In step (1), first, normal temperature pellets (resin material) are charged from the charging port 2a of the annular die 2. The charged pellets are melted in the flow path 2 b of the annular die 2 to become a melt 30. Next, by pushing down the piston 3, the melt 30 is continuously discharged radially from the discharge port 2 c toward the inner wall of the cylindrical mold 4. In addition to the structure in which the resin composition is melted with the annular die 2, a structure in which a melt of the resin composition is charged into the annular die 2 may be used.

  Next, in the step (2), the tip of the melt 30 discharged from the annular die 2 is injected into the resin injection groove 9. (See FIG. 6 (b)).

  Next, in the step (3), the state where the tip of the melt 30 is in close contact with the resin injection groove 9 is maintained. From this state, the cylindrical mold 4 is raised while the piston 3 is pushed down at a desired speed and the melt 30 is continuously discharged radially from the annular die 2 in the circumferential radial direction. Thus, the melt 30 is applied to the inner wall of the cylindrical mold 4. Thereby, the cylindrical layer 1 is formed in the inner wall of the cylindrical metal mold | die 4 (refer FIG.6 (c)).

  In step (3), the speed at which the piston 3 is pushed down corresponds to the outflow speed of the melt 30 from the discharge port 2c. By controlling the outflow speed and the ascent speed of the cylindrical mold 4, The thickness of the cylindrical layer 1 can be controlled. Further, in the step (3), when the cylindrical layer 1 is formed, the cylindrical die 4 may be fixed and the annular die 2 may be lowered. Alternatively, the cylindrical die 4 may be raised and the annular die 2 may be lowered. That is, in the step (3), the cylindrical layer 1 may be formed on the inner wall of the cylindrical mold 4 by moving the annular die 2 relative to the cylindrical mold 4 in the axial direction.

  Next, in step (4), the cylindrical layer 1 is brought into close contact with the inner wall of the cylindrical mold 4. Specifically, following the step (3) or in parallel with the step (3), gas is injected into the cylindrical mold 4 from the gas injection means (not shown) through the injection port 8 (see FIG. 6 (c)). At this time, in the internal space of the cylindrical mold 4, since the tip of the melt 30 is injected into the resin injection groove 9, the gas communication is cut off, and the cylindrical mold 4, the cylindrical layer 1, The internal space 50 partitioned by the annular die 2 is pressurized. As a result, the cylindrical layer 1 is brought into close contact with the inner wall of the cylindrical mold 4. When the cylindrical layer 1 is in close contact with the inner wall of the cylindrical mold 4, the cylindrical layer 1 is deprived of heat by the cylindrical mold 4 and cooled. At this time, the cylindrical layer 1 starts to solidify by adjusting the temperature of the cylindrical mold 4 to be equal to or lower than the melting point of the resin composition. Generally, since shrinkage occurs when the melt containing the thermoplastic resin is solidified, the cylindrical layer 1 is easily peeled off from the inner wall of the cylindrical mold. However, in this embodiment, the internal space of the cylindrical mold 4 is sealed in the step (2), and the cylindrical layer 1 is continuous from the tip of the melt 30 in the step (3). Furthermore, only the internal space 50 described above in step (4) is pressurized. Therefore, in step (4), gas does not enter the gap between the inner wall of the cylindrical mold 4 and the cylindrical layer 1. Therefore, by pressurizing the internal space 50 with the gas injected from the injection port 8, the cylindrical layer 1 can be solidified while being in close contact with the inner wall 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, it becomes possible to stabilize the outer diameter accuracy of the solidified product of the cylindrical layer 1 formed on the inner wall of the cylindrical mold 4 at the same level as the inner diameter of the cylindrical mold 4.

  The gas injected from the inlet 8 is preferably air or an inert gas typified by nitrogen gas.

  Next, in the step (5), the cylindrical layer 1 is solidified (see FIG. 6C). At this time, the temperature of the cylindrical mold 4 is not less than the glass transition point of the resin composition and not more than the melting point of the resin composition by a temperature sensor (not shown) and a heater and a cooler (not shown) that can be controlled based on the detection result. It is preferable to adjust the temperature range. This is because the temperature of the cylindrical mold 4 is not lower than the glass transition point and not higher than the melting point, and the cylindrical layer 1 is gradually cooled close to the inner wall of the cylindrical mold 4 so that the degree of crystallinity is increased. It is because it becomes higher and the strength can be increased.

  It is also possible to carry out the cylindrical mold 4 in a general room temperature (25 ° C.) state without actively controlling the temperature of the resin composition above the glass transition temperature and below the melting point of the resin composition. In this case, the cylindrical layer 1 adheres to the cylindrical mold 4 and starts to solidify immediately. Since the cylindrical mold 4 is at room temperature, the cylindrical layer 1 is rapidly cooled and solidified without progressing crystallization, so that a seamless belt having high flexibility and high bending fatigue strength can be obtained. Next, the cylindrical body made of the resin composition formed on the inner wall of the cylindrical mold 4 is taken out from the inner wall. Specifically, after the cylindrical layer 1 is sufficiently solidified, the gas injection from the injection port 8 is stopped. Next, the suction of the end of the cylindrical body is stopped, and the cylindrical body is taken out from the cylindrical mold 4 using unillustrated taking-out means. Then, a seamless belt is cut out from the cylindrical body.

  Since the surface of the inner wall of the cylindrical mold 4 is accurately transferred to the surface shape of the seamless belt obtained by the manufacturing process described above, a seamless belt with a uniform surface shape and less unevenness can be manufactured at low cost.

  In the present invention, the contact means used in the step (2) is not limited to the resin injection groove 9. For example, a structure using the porous body 11 as shown in FIG. 3 as the close contact means may be used, or a suction pad 10 having the manifold 12 and the slit 13 as shown in FIG. 4 is used as the close contact means. May be.

  Further, each of the resin injection groove 9, the porous body 11, and the suction pad 10 is connected to a suction means 14 (see FIGS. 3 and 5) disposed outside the cylindrical mold 4, and the measurement means 15 ( The suction pressure may be measured with reference to FIGS. 3 and 5. When the suction pad 10 is used, in the step (2), the tip portion of the discharged melt 30 is sucked to the suction pad 10 by the suction means 14. Thereby, the communication of the gas from the inside of the cylindrical mold to the outside of the cylindrical mold through the suction pad 10 is blocked. In close contact, the suction pressure is measured by the measuring means 15 as shown in FIG. 3, and the measured value of the measuring means 15 is compared with a predetermined set value by the calculating means 16 to detect the close contact state. To do. Thereby, the gas communication from the inside of the cylindrical mold 4 to the outside of the cylindrical mold through the suction pad 10 is reliably blocked. The close contact state may be detected by measuring the suction flow rate of the suction means 14 by the measurement means 15. In this way, by determining the time for starting the movement (rise) of the cylindrical mold 4 based on the result of detecting the contact state, an excessive amount of resin at the tip of the cylindrical layer 1 is suppressed, Material waste can be reduced.

Example 1
Using the seamless belt manufacturing apparatus having the configuration shown in FIG. 1, an electrophotographic seamless belt was manufactured along the first to fifth steps.

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

  The cylindrical mold 4 has an inner diameter of 290 mm and an axial length of 670 mm. Further, the surface of the inner wall corresponds to the surface roughness so that the surface of the seamless belt has a predetermined surface roughness [ten-point average roughness (Rzjis, JIS K0601-2001) = 0.4 μm]. Surface treatment was performed to have surface roughness. Further, the temperature of the cylindrical mold 4 is controlled to 200 ° C. by temperature control means (not shown). The size of the annular die 2 is the outermost diameter 282 mm, the width 2 mm of the flow path 2 b, and the width (slit width) 1 mm of the discharge port 2 c. A hole (not shown) penetrating above the annular die 2 and the inlet 2a are opened when the piston 3 reaches the rising end. Further, the annular die 2 is controlled to 380 ° C. by temperature control means (not shown).

  First, as shown in FIG. 6A, the piston 3 is raised to the rising end to secure a space in the flow path 2b. And the melt 30 is produced | generated by throwing a suitable quantity of normal temperature pellets into the flow path 2b from the inlet 2a of the cyclic | annular die | dye 2 and melting a pellet. Next, the cylindrical mold 4 is disposed so that the suction pad 10 has a height equivalent to the discharge port 2 c of the annular die 2.

  Next, as shown in FIG. 6 (b), the melt 30 is continuously discharged radially from the discharge port 2c toward the inner wall of the cylindrical mold 4 by pushing down the piston 3 (first step). ). Thereafter, the discharged melt 30 is brought into close contact with the manifold 12 and the slit 13 in the suction pad 10 by the suction means 14 (second step). At this time, the contact state was detected by measuring the suction pressure with the measuring means 15, and it was detected that the communication of the gas inside the cylindrical mold 4 was reliably blocked.

  Next, as shown in FIG. 6C, in the state where the melt 30 is in close contact with the suction pad 10, the cylindrical mold 4 is detected in close contact while the piston 3 is lowered at 0.2 mm / second. Based on the results, the rate was increased at 15 mm / second (third step). At the same time, nitrogen gas was injected into the internal space 50 from the injection port 8 (fourth step). Thereby, a layer of the melt 30 was formed on the inner wall of the cylindrical mold 4, and the layer was brought into close contact with the inner wall of the cylindrical mold 4. At this time, the temperature of the cylindrical mold 4 was adjusted to 200 ° C., which is lower than the melting point of the resin composition. Thus, a cylindrical layer 1 was obtained (fifth step).

  After the cylindrical layer 1 having a length of about 400 mm was formed, the lowering of the piston 3 was stopped, and the cylindrical mold 4 on which the cylindrical layer 1 was formed was further raised to continue from the discharge port 2c. The tube layer 1 was cut. Next, the injection of compressed air was stopped, the tip of the melt 30 injected into the suction pad 10 was cut, and the cylindrical body made of the resin composition formed on the inner wall of the cylindrical mold 4 was taken out. Finally, both ends of the taken-out cylindrical pair were cut to obtain a seamless belt.

  The seamless belt obtained by the above-described procedure did not show distortion even when stretched by two parallel rollers, and had a stable shape with a thickness of 100 μm. Further, since there were no branching and joining points in the flow path, no weld line was generated, and a uniform strength was exhibited over the entire surface of the belt. The volume resistivity could be formed without in-plane spots. Furthermore, by controlling the temperature of the cylindrical mold 4 to be not lower than the glass transition point and not higher than the melting point, a seamless belt having a crystallinity of 20% or higher can be obtained, and a seamless belt having high tensile strength and high surface hardness can be obtained. It was.

1 cylindrical layer 2 annular die 4 cylindrical mold 30 melt 50 internal space

Claims (6)

A cylindrical mold, coaxially disposed with the cylindrical mold, movable in the axial direction relative to the cylindrical mold in the vicinity of the inner wall of the cylindrical mold, and heat An annular die capable of discharging a melt of a resin composition containing a plastic resin in a radial direction, and a method of manufacturing a seamless belt using a seamless belt manufacturing apparatus,
(1) a first step of extruding the melt radially from the annular die;
(2) a second step of bringing the tip of the extruded melt into close contact with the contact means provided in the cylindrical mold;
(3) With the tip of the melt in close contact with the contact means, the cylindrical mold and the annular die are moved relative to each other in the axial direction so that the melt is placed on the inner wall of the cylindrical mold. A third step of applying and forming a continuous cylindrical layer from the tip of the melt;
(4) Gas is filled in the internal space partitioned by the tubular layer, the tubular mold, and the annular die, and the tubular layer is formed by the pressure of the gas to the inner wall of the tubular mold. A fourth step of closely adhering to
(5) A fifth method for solidifying the cylindrical layer, and a method for producing a seamless belt.   The contact means is a resin injection groove extending in the radial direction from the inner wall of the cylindrical mold, and in the second step, the tip of the melt is injected into the resin injection groove to form the cylindrical mold. The method for producing a seamless belt according to claim 1, wherein the belt is in close contact.   The contact means penetrates from the inner wall to the outer wall of the cylindrical mold, and in the second step, the melt means is melted from the contact means by using a suction means disposed outside the cylindrical mold. The method for producing a seamless belt according to claim 1, wherein the tip is sucked and brought into close contact with the cylindrical mold.   The contact means is a resin injection groove extending in the radial direction from the inner wall of the cylindrical mold and penetrating to the outer wall, and in the second step, the tip of the melt is injected into the resin injection groove; and The tip of the melt is brought into close contact with the cylindrical mold by suction from the resin injection groove using a suction means disposed outside the cylindrical mold. Seamless belt manufacturing method.   In the second step, the contact state is detected, the measured value of the contact state is compared with a predetermined set value, and the time for starting the relative movement in the third step is determined by the comparison operation. The method for producing a seamless belt according to claim 3 or 4, wherein the method is determined from a result.   A cylindrical mold provided with a close contact means, and disposed coaxially with the cylindrical mold, and is movable in the axial direction relative to the cylindrical mold in the vicinity of the inner wall of the cylindrical mold. And an annular die capable of discharging a melt of a resin composition containing a thermoplastic resin in the radial direction.

Images