JP2007025135A - Method for manufacturing electrophotographic seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic seamless belt excellent in dimensional accuracy, transferring performance and durability. <P>SOLUTION: The electrophotographic seamless belt is manufactured by an injection stretch blow molding process including steps of: forming a preform by injection-molding a thermoplastic resin mixutre; a step of heating the formed preform; primarily stretching the preform in a metal mold with a stretching rod; and secondarily stretching the preform by blowing gas. The temperature of the metal mold for stretch blow molding is regulated to the heating temperature of the preform or below. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an intermediate transfer belt or a transfer conveyance belt used in an image forming apparatus such as a copying machine or a color printer using an electrophotographic system.

Intermediate transfer belt (Before transferring the toner image formed on the photosensitive member to a transfer material such as paper, the toner image is temporarily transferred onto the intermediate transfer belt, and then the toner image on the intermediate transfer belt is transferred to the intermediate transfer belt. Toner formed on an image carrier such as a photosensitive member, and a transfer and conveyance belt (a belt used for obtaining an image by transferring to a transfer material) and a transfer and conveyance belt (transfer material such as paper) An image forming device that uses a belt used to transfer an image directly to a transfer material) synthesizes and reproduces a color image and a multicolor image by sequentially laminating and transferring multiple component color images of color image information and multicolor image information. Effective as a color image forming apparatus or a multicolor image forming apparatus for outputting an image formed product, or an image forming apparatus having a color image forming function or a multicolor image forming function. Is currently a tube Examples include extrusion, inflation, centrifugal molding, blow molding, and injection molding.

  However, the above methods have their respective problems as methods that the inventors of the present invention are really seeking. For example, in the extrusion molding and injection molding methods, the production of a thin layer belt of 100 μm or less has a considerable difficulty, and even if possible, the film thickness unevenness and the electric resistance unevenness affected by it tend to occur, and seamless. As a belt, for example, the performance and quality stability as an intermediate transfer belt are hindered.

  When sheets are joined, there is a problem of a step difference in joints and a decrease in tensile strength. In addition, methods using solvents such as coating and centrifugal molding increase the number of steps and cost, such as production of coating liquid, coating, molding, and removal of solvent. It also includes matters that affect the environment, such as solvent recovery.

  However, among several molding methods mentioned above, the blow molding method, particularly the stretch blow molding method, stabilizes the outer dimensions by using a mold which is a characteristic of blow molding, and further becomes a thermoplastic resin as a raw material. By stretching the film, molecular orientation occurs, crystallization causes belt strength to improve, and repeatability is high, so products of uniform quality can be stabilized and molded at high speed. Therefore, it is a molding technique that enables cost reduction.

  However, the following problems are also involved in a seamless belt produced by a stretch blow molding method.

  In general, when a belt is produced by stretch blow molding, the outer dimensions can be made highly accurate by a stretch blow molding die. Further, the stretching at this time causes the molecular orientation of the thermoplastic resin, which is the raw material of the blow molded product, and the crystallization proceeds. When this phenomenon occurs in the entire blow molded product, the film thickness can be made uniform and the strength can be improved.

  However, on the other hand, it is extremely difficult to blow uniformly at the time of blow molding because of the production method in which a high-pressure gas is introduced into the preform to expand and shape. For this reason, in one molded body, the molecular orientation caused by stretching at the time of blowing is not necessarily uniform, and accordingly, uneven crystallization may occur.

  In addition, since it is necessary to make the thickness 250 μm or less, which is a thickness that is not normally performed as stretch blow molding, for use as a belt, if uneven crystallization occurs due to stretch blow molding, it can be obtained. Further, slight unevenness is easily generated on the surface of the belt, and the entire surface may be swelled. If a belt in such a state is used as an intermediate transfer belt or a transfer belt, the uniformity of transferability within the belt is impaired, the density unevenness of the image deteriorates, and the running performance becomes unstable, resulting in durability of the belt. There was a case where the sex could not be obtained.

Patent Documents 1 and 2 disclose a seamless belt for electrophotography by stretch blow molding.
Japanese Patent Laid-Open No. 5-0623130 JP 2001-018284 A

  However, the techniques disclosed in Patent Documents 1 and 2 have not yet solved the problems described above.

  Patent Document 1 discloses a production method for obtaining a seamless belt for electrophotography by stretch blow molding.

  However, the manufacturing method described in Patent Document 1 is a method in which the stretch blow mold is temperature-controlled at a temperature higher than the preform heating temperature, and the molded article immediately after blow is heated and cured, and when the molded article is taken out from the mold. It takes a lot of time for cooling to be performed. Therefore, there are problems in productivity and cost.

  The present invention relates to a method for producing an electrophotographic seamless belt which is excellent in productivity and cost and does not cause undulation on an electrophotographic seamless belt such as an intermediate transfer belt and a transfer conveyance belt produced by stretch blow molding. It is to provide.

  The present invention also provides a method for producing an electrophotographic seamless belt excellent in dimensional accuracy, transferability and durability.

  Furthermore, the present invention provides an electrophotographic image forming apparatus having the electrophotographic seamless belt.

  At least a step of forming a preform by injection molding a thermoplastic resin mixture, a step of heating the formed preform, a step of primarily stretching the preform with a stretching rod in a mold, and blowing a gas An electrophotographic seamless belt manufactured by an injection stretch blow molding method having a step of secondary stretching by adjusting the temperature of a mold for stretch blow molding below the heating temperature of the preform The object of the present invention is achieved by a method for producing a photographic seamless belt.

  According to the present invention, an electrophotographic seamless belt excellent in productivity and cost, free from undulation, and excellent in dimensional accuracy, transferability, and durability can be obtained by stretch blow molding.

  In the present invention, a step of forming a preform by injection molding a thermoplastic resin mixture, a step of heating the formed preform, and a step of primarily stretching the preform with a stretching rod in a mold In a seamless belt for electrophotography produced by an injection stretch blow molding method having a step of secondary stretching by blowing gas, it is preferable that the temperature of the mold for stretch blow molding is controlled below the heating temperature of the preform. . Here, the mold temperature control is not limited as long as it is equal to or lower than the preform heating temperature, and varies depending on the material constituting the preform, but is preferably 40 ° C or higher, more preferably 60 ° C or higher. It is.

  Here, in the present invention, the temperature of the mold for stretch blow molding to be equal to or lower than the heating temperature of the preform is excellent in productivity and cost, and exhibits the effect of removing the swell appearing on the surface of the blow molded product. explain.

  Since the material used in the present invention is a thermoplastic resin mixture, the crystallization temperature is lower than that of the non-mixed system. Therefore, even when the mold is heated to a temperature below the preform heating temperature, an annealing effect can be obtained. As a result, even when non-uniform blow molding is performed, it is possible to make the generated crystallization unevenness uniform and prevent the occurrence of waviness.

  The annealing in this case is a method in which the preform immediately after expansion is heated to the vicinity of its crystallization temperature, crystallization is uniformly promoted, and the entire crystallization unevenness is eliminated. By this method, the swell can be effectively removed. Moreover, the crystallization temperature of the preform shown here is determined from the DSC measurement of the preform.

  In the present invention, when the stretch blow-molded product is removed from the mold, the temperature of the stretch blow-molded product needs to be cooled to the Tg or less in the mold in order to prevent deformation occurring at that time. At this time, when the mold is temperature-controlled higher than the preform heating temperature, the influence of the mold temperature is great even when cooling blow is performed after blow molding, and the temperature of the stretch blow molded product is lowered to Tg or less. It takes a lot of time. On the other hand, when the temperature of the mold is controlled to be equal to or lower than the preform heating temperature, the stretch blow-molded product is instantaneously lowered to Tg or less by cooling blow after blow molding, so that the tact is short and deformation at the time of take-out is reduced. It does not happen and is preferable.

  Here, it is preferable that the surface waviness of the present invention is an average wavelength of less than 7 mm and an average wave height of 20 μm or less.

  In the present invention, by setting the swell to the above range or removing it, the following effects can be obtained. For example, the difference in distance that the toner moves from the surface of the photosensitive drum, which is the first image carrier, to the intermediate transfer member becomes uniform, and transfer unevenness during primary transfer can be reduced. In the primary transfer after the second color, the retransfer of the convex portion is also reduced, and the cleaning failure due to the toner remaining in the concave portion after the secondary transfer can be reduced.

  Furthermore, when durability image evaluation is performed in each environment, even when belt contraction or relaxation occurs, circumferential wrinkles can be prevented, and belt running performance during a durability test can be kept good. This is considered to be because the difference in the undulation portion of the belt relaxation and contraction is reduced because the undulation is small.

  The stretch blow mold used in the present invention is a horizontally divided cylindrical mold in which the cylindrical body portion is not divided vertically as shown in FIG. 1 so that no parting line enters the image transfer portion. Is desirable. In the case of a vertically split mold in which the parting line enters the image transfer part as shown in Fig. 2, a step occurs on the parting line, so the horizontal stripe appears in the image or the parting occurs when the belt is rotated. This is because vibration may occur at the level difference of the part and banding may occur. More preferably, the temperature control of the stretch blow mold in the present invention is a cylindrical temperature control.

  In the present invention, the cylindrical temperature control is one in which eight heaters are incorporated at equal intervals in the cylindrical shape as shown in FIG. 3, for example, but the number is not limited. Further, the cylindrical heating means may be other than the heater, and for example, a liquid such as oil or a gas such as hot air may be used, and is not limited as long as the cylindrical shape can be adjusted to a high temperature. Examples of the heater include a cartridge heater, a band heater, a quartz tube heater, and a blade heater, but the cartridge heater is more preferable in that the temperature can be stably controlled. The temperature of the cylindrical shape is measured using a heat transfer body or the like.

  In the present invention, the preform heating temperature is the surface temperature of the preform 5 seconds before the start of blow molding (when the preform enters the mold and the mold is closed). The surface temperature measurement is not particularly limited as long as it is a thermometer, but a non-contact thermometer is preferable so that it can be molded after the measurement, and a radiation thermometer is particularly preferable. It is necessary to set the emissivity of the object before.

As shown in FIG. 4, the heating in the step of heating the preform is performed at each position divided into three or more in the longitudinal direction of the preform 104.
This is preferably performed by the heater 111. If this is a heater divided into three or more when temperature unevenness occurs when it is stretched in the longitudinal direction of the preform, the heating temperature unevenness of the preform is reduced by controlling the heaters independently. This is because the transfer unevenness can be reduced since the film can be stretched more uniformly in the longitudinal direction.

  Further, as shown in FIG. 4, the heater distance to the preform is also changed as shown in the heaters a, b, and c, for example, so that more precise control is possible. Therefore, it is desirable to adjust the heater distance. Although there is no restriction | limiting in particular regarding a heater, A halogen heater, a far-infrared heater, an IH heater, etc. can be used. Further, the preform is preferably preheated while rotating around the preform longitudinal axis in order to prevent uneven heating.

In the seamless belt for electrophotography of the present invention, the volume resistivity range in which a good image can be obtained is preferably 9 × 10 ³ Ωcm to 9 × 10 ¹⁴ Ωcm. If the volume resistivity is less than 1 × 10 ³ Ωcm, the resistance is too low to obtain a sufficient transfer electric field, and image omission and roughness are likely to occur.

On the other hand, if the volume resistivity is higher than 9 × 10 ¹⁴ Ωcm, it is necessary to increase the transfer voltage, which causes an increase in power source size and cost, which is not preferable. In order to adjust the electric resistance value of the electrophotographic endless belt (belt-like substrate) of the present invention, various conductive resins can be used. Non-filler resistance adjusters include low molecular weight ionic conductive agents such as various metal salts and glycols, antistatic resins containing ether bonds and hydroxyl groups in the molecule, or organic polymer compounds exhibiting electronic conductivity. Etc.

  Examples of the thermoplastic resin used in the present invention include olefin resins such as polyethylene and polypropylene, polystyrene resins, acrylic resins, ABS resins, polyester resins (PET, PBT, PEN, PAR, etc.), polycarbonate resins, Sulfur-containing resins such as polysulfone, polyethersulfone and polyphenylene sulfide, fluorine atom-containing resins such as polyvinylidene fluoride and polyethylene-tetrafluoroethylene copolymer, polyurethane resin, silicone resin, ketone resin, polyvinylidene chloride, thermoplasticity One kind or two or more kinds of polyimide resins, polyamide resins, modified polyphenylene oxide resins, etc., and various modified resins and copolymers thereof can be used.

  Further, the thermoplastic resin used in the present invention is a resin mixture having thermoplasticity. For example, even if a thermoplastic resin and a thermosetting resin powder are mixed, the final resin mixture is If it has thermoplasticity, it is called a thermoplastic resin.

The thickness of the intermediate transfer belt is preferably in the range of 40 μm to 250 μm. If it is less than 40 μm, the molding stability is lacking and thickness unevenness is likely to occur.
The durability strength is also insufficient, and the belt may be broken or cracked. On the other hand, if the wall thickness exceeds 250 μm, the material increases and the cost increases, and the difference in peripheral speed between the inner surface and the outer surface at the stretched shaft part of a printer or the like increases, causing problems such as image scattering due to contraction of the outer surface. Are likely to occur, the bending durability decreases, the belt rigidity becomes too high, the driving torque increases, and the main body becomes larger and the cost increases.

  An example of the stretch blow molding method of the present invention will be described with reference to FIGS.

  At least a thermoplastic resin and a conductive material are uniformly kneaded and dispersed in advance, and the pellets are injected into the injection mold 102 by the extruder 101 shown in FIG. The injection mold 102 can be moved up and down.

  Next, in the heating step shown in FIG. 6, the preform 104 is heated to a desired temperature while being continuously moved in the heating furnace 107. The heating conditions can be set in a timely manner according to the blow mold configuration, belt material, and blow conditions.

  The heating furnace 107 may be provided with one or a plurality of heaters on both sides or one side, or may be a hot air furnace or a hot air furnace. A heating furnace provided with a heater is preferable. As the heater, heat ray heating, halogen heater heating, infrared heating, electromagnetic induction heating, or the like can be used. However, halogen heater heating, infrared heating, electromagnetic induction heating, etc. are preferable because they can be heated at a low equipment cost.

  Next, as shown in FIGS. 7 to 9, stretch blow molding is performed. After heating, the preform 104 is first stretched longitudinally in the mold by the stretching rod 109 and the primary air pressure, and further expanded along the inner surface of the mold by the secondary air pressure. Next, as shown in FIG. 7, the blow mold 108 is opened and the stretched molded product 112 is taken out. Finally, the upper and lower sides of the stretched molded product 112 obtained as shown in FIG. 10 can be cut to obtain the electrophotographic seamless belt 115 of the present invention.

  Next, the electrophotographic apparatus of the present invention will be described with specific examples.

  FIG. 11 shows a schematic configuration of a four-process full-color image forming apparatus using the electrophotographic seamless belt of the present invention as an intermediate transfer belt.

  In FIG. 11, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven at a predetermined peripheral speed (process speed) in the direction of an arrow.

  The electrophotographic photosensitive member 1 is uniformly charged to a predetermined polarity and potential by the primary charger 2 during the rotation process, and then exposed from exposure means (not shown) such as slit exposure, laser beam scanning exposure, and LED exposure. By receiving the output (image exposure) 3 that is output, an electrostatic latent image corresponding to a first color component image (for example, a yellow color component image) of the target color image is formed.

  Next, the electrostatic latent image is developed with yellow toner Y as the first color by the first developing device (yellow color developing device 4Y). At this time, the developing units of the second to fourth developing units (magenta developing unit 4M, cyan developing unit 4C, and black developing unit 4K) are turned off and do not act on the electrophotographic photosensitive member 1. The first color yellow toner image is not affected by the second to fourth developing units.

  The intermediate transfer belt 5 is rotationally driven in the clockwise direction at substantially the same peripheral speed as that of the electrophotographic photosensitive member 1 (for example, 97 to 103% with respect to the peripheral speed of the electrophotographic photosensitive member 1).

  In the process in which the yellow toner image of the first color formed and supported on the electrophotographic photoreceptor 1 passes through the nip portion between the electrophotographic photoreceptor 1 and the intermediate transfer belt 5, a primary transfer member (primary transfer roller) 6. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5 by the electric field formed by the primary transfer bias applied to the intermediate transfer belt 5. The primary transfer bias is applied from the bias power supply 30 with a polarity opposite to that of the toner. The applied voltage is, for example, in the range of +100 V to 2 kV. The surface of the electrophotographic photosensitive member 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 5 is cleaned by the cleaning member 13.

  Thereafter, similarly, a second color magenta toner image, a third color cyan toner image, and a fourth color black toner image are sequentially superimposed and transferred onto the intermediate transfer belt 5, and a composite color corresponding to the target color image is obtained. A toner image is formed.

  Reference numeral 7 denotes a secondary transfer member (secondary transfer roller) which is arranged in parallel with the secondary transfer counter roller 8 so as to be separated from the lower surface portion of the intermediate transfer belt 5 in a bearing. Reference numeral 12 denotes a tension roller.

  In the primary transfer process of the first to third color toner images from the electrophotographic photoreceptor 1 to the intermediate transfer belt 5, the secondary transfer member 7 can be separated from the intermediate transfer belt 5.

  The composite color toner image transferred onto the intermediate transfer belt 5 is brought into contact with the intermediate transfer belt 5 and the secondary transfer roller 7 from the paper feed roller 11 through the transfer material guide 10 in synchronization with the rotation of the intermediate transfer belt. Transfer (secondary transfer) is performed on the transfer material P fed to the nip at a predetermined timing by the secondary transfer bias applied from the secondary transfer member 7. The applied voltage of the secondary transfer bias is, for example, in the range of +100 V to 2 kV.

  The transfer material P that has received the transfer of the toner image is introduced into the fixing device 14 and is heat-fixed to output an image.

  After the image transfer to the transfer material P is completed, a cleaning charging member 9 is brought into contact with the intermediate transfer belt 5 and is not transferred to the transfer material P by applying a bias having a polarity opposite to that of the electrophotographic photosensitive member 1. In addition, a charge having a polarity opposite to that of the electrophotographic photosensitive member 1 is applied to the toner (transfer residual toner) remaining on the intermediate transfer belt 5. 32 is a bias power source. The transfer residual toner is electrostatically transferred to the electrophotographic photosensitive member 1 at and near the nip portion with the electrophotographic photosensitive member 1, thereby cleaning the intermediate transfer member.

  FIG. 10 shows a schematic configuration of a full-color image forming apparatus using the electrophotographic seamless belt of the present invention as a transfer conveyance belt.

  The image forming apparatus shown in FIG. 12 has four image forming units arranged in parallel as electrophotographic process means, and each image forming unit includes an electrophotographic photosensitive member 1, a primary charger 2, a developing device 4, and a cleaning device. The member 13 is configured to be included. The developing devices 4Y, 4M, 4C, and 4K contain yellow (Y), magenta (M), cyan (C), and black (BK) toners, respectively.

  In each image forming unit, the electrophotographic photosensitive member 1 is rotationally driven in the direction of the arrow at a predetermined speed, and these are uniformly charged by the primary charger 2 to a predetermined polarity and potential. Each of the electrophotographic photosensitive members 1 thus charged is subjected to exposure 3 output from an exposure means (not shown), whereby an electrostatic latent image corresponding to each color component image of the target color image is obtained. The formed electrostatic latent images are developed by the developing devices 4Y, 4M, 4C, and 4K, and are visualized as yellow toner images, magenta toner images, cyan toner images, and black toner images, respectively.

  Each color toner image formed and supported on the electrophotographic photosensitive member 1 is transferred to the image forming unit by transferring the transfer material P from the paper feed roller 11 through the transfer material guide 10 to the transfer conveyance belt 16 and moving therewith. The yellow toner image, the magenta toner image, the cyan toner image, and the black toner image are transferred in a superimposed manner by a transfer bias applied from the transfer member (transfer roller) 18 when passing through the image, and are combined corresponding to the target color image. A color toner image is formed. The transfer bias is applied from the bias power supply 30 with a polarity opposite to that of the toner. The applied voltage is, for example, in the range of +100 V to 2 kV.

  The recording paper P that has received the transfer of each color toner image as described above is discharged by the separation charger 21 and separated from the transfer conveyance belt 16, and then conveyed to the fixing device 14 to heat and fix the color toner image. Received image is output.

  FIG. 11 shows a schematic configuration of a full-color image forming apparatus of a quadruple photosensitive system using the electrophotographic seamless belt of the present invention as an intermediate transfer belt.

  The image forming apparatus shown in FIG. 13 has four image forming units arranged in parallel as electrophotographic process means, and each image forming unit includes an electrophotographic photosensitive member 1, a primary charger 2, a developing device 4, and a cleaning device. The member 13 is configured to be included. The developing devices 4Y, 4M, 4C, and 4K contain yellow (Y), magenta (M), cyan (C), and black (BK) toners, respectively.

  In each image forming unit, the electrophotographic photosensitive member 1 is rotationally driven in the direction of the arrow at a predetermined speed, and these are uniformly charged by the primary charger 2 to a predetermined polarity and potential. Each of the electrophotographic photosensitive members 1 thus charged is subjected to exposure 3 output from an exposure means (not shown), whereby an electrostatic latent image corresponding to each color component image of the target color image is obtained. The formed electrostatic latent images are developed by the developing devices 4Y, 4M, 4C, and 4K, and are visualized as yellow toner images, magenta toner images, cyan toner images, and black toner images, respectively.

  The intermediate transfer belt 5 is rotationally driven in the clockwise direction at substantially the same peripheral speed as that of the electrophotographic photosensitive member 1 (for example, 97 to 103% with respect to the peripheral speed of the electrophotographic photosensitive member 1).

  Each color toner image formed and supported on the electrophotographic photosensitive member 1 passes from the primary transfer member (primary transfer roller) 6 to the intermediate transfer belt in the process of passing through the nip portion between the electrophotographic photosensitive member 1 and the intermediate transfer belt 5. 5 is transferred onto the outer peripheral surface of the intermediate transfer belt 5 by the primary transfer bias applied to the intermediate transfer belt 5 (primary transfer) to form a composite color toner image corresponding to the target color image. The primary transfer bias is applied from the bias power supply 30 with a polarity opposite to that of the toner. The applied voltage is, for example, in the range of +100 V to 2 kV.

  Reference numeral 7 denotes a secondary transfer member (secondary transfer roller) which is arranged in parallel with the secondary transfer counter roller 8 so as to be separated from the lower surface of the intermediate transfer belt 5 in a bearing. Reference numeral 12 denotes a tension roller.

  The composite color toner image transferred onto the intermediate transfer belt 5 is brought into contact with the intermediate transfer belt 5 and the secondary transfer roller 7 from the paper feed roller 11 through the transfer material guide 10 in synchronization with the rotation of the intermediate transfer belt. Transfer (secondary transfer) is performed on the transfer material P fed to the nip at a predetermined timing by the secondary transfer bias applied from the secondary transfer member 7. The applied voltage of the secondary transfer bias is, for example, in the range of +100 V to 2 kV.

  The transfer material P that has received the transfer of the toner image is introduced into the fixing device 14 and is heat-fixed to output an image.

  The toner remaining on the intermediate transfer belt is collected on the photosensitive member by the cleaning charging member 9 as in FIG.

  In FIG. 14, the melting part in the injection molding machine will be described. However, the injection molding machine used in the present invention is not limited to that shown in FIG.

  In FIG. 14, reference numeral 1 denotes a heating cylinder, and an injection screw 2 is built inside.

  Reference numerals 4a, 4b, 4c, and 4d denote first heaters that heat the heating cylinder 1 and heat and melt the fed resin material.

  Reference numerals 6a and 6b denote second heaters for maintaining a resin material for performing a sealing action, which will be described later, in a predetermined temperature state, and are disposed on the rear end side of the heating cylinder. The heating cylinder is provided with sensors for controlling energization of the first heater and the second heater and measuring the temperature of each part of the cylinder.

  The injection screw 2 is provided with a groove or blade portion 2A for kneading and injecting the supplied resin material and a groove or blade portion 2B opposite to the blade portion 2A provided on the rear end side of the screw. It has been.

  The base portion 2C of the screw is a screw drive shaft 2D.

  Reference numeral 8 denotes a hopper, which is supplied with a resin agent from the agent supply means, is connected to a resin agent supply port of the heating cylinder, and feeds the resin agent into the heating cylinder by opening / closing an unillustrated opening / closing shutter. .

  Reference numeral 10 denotes a vacuum exhaust pipe attached to the supply passage 8A of the hopper 8 and is connected to a vacuum pump.

  After supplying a predetermined amount of the resin material into the hopper 8, the lid of the hopper is closed and sealed, the shutter (not shown) is opened, and the resin material is fed into the heating cylinder from the supply port of the hopper.

  The heating cylinder is heated by energizing the heaters from the first and second heating means.

  As the temperature of the heating cylinder rises, the resin material becomes molten, and the molten resin material closes the nozzle port 1A at the front end of the cylinder, and the resin at the rear end of the cylinder also melts. Is kept in a confidential state with a molten resin material.

  In this example, the resin material having the above formulation was used.

  When the sensor detects that the in-cylinder temperature has reached a predetermined temperature, the vacuum pump 18 is operated by the vacuum means 18 to perform a suction operation.

  The screw driving means performs kneading and metering of the resin material by rotating the screw. Subsequently, compression and injection are performed, and the molten resin material is injected into the molding die.

  Between the heating process and the injection process of the resin material, the molten resin material closes the opening and the gap of the cylinder in the heating cylinder, and the sealed state is maintained. This prevents oxidation and discoloration of the resin material.

  In this example, a part of the molten resin material is pushed in the direction of the rear end of the screw by the blades 2b arranged in the direction opposite to the injection direction by the rotational operation of the screw driving means, and the gap between the heating cylinder and the screw is reduced. In the closed state, the sealing action is executed.

Hereinafter, methods for measuring various physical properties according to the present invention will be described.
<Measurement method of swell>
The belt surface waviness measurement method was measured based on JIS B601. The average wavelength of the present invention is expressed by the average interval Sm (ISO) obtained by a surface roughness meter, and the average wave height is 10 points. The average roughness Rz (JIS) is used. As measurement conditions at this time, the measurement length is 80 mm and the measurement speed is 2 mm / s. In addition, the sample used what cut out the stretch blow molding goods.
<Volume resistance measurement method>
The measuring device uses an ultra-high resistance meter R8340A (manufactured by Advantest) as the resistance meter, and the sample box TR42 (manufactured by Advantest) as the sample box, but the main electrode has a diameter of 25 mm and the guard ring electrode has an inner diameter. 41 mm and outer diameter 49 mm.

  Samples are prepared as follows.

  First, the electrophotographic belt is cut into a circle having a diameter of 56 mm with a punching machine or a sharp blade. On one side of the cut-out circular piece, an electrode is provided on the entire surface by a Pt—Pd vapor deposition film, and on the other side, a main electrode having a diameter of 25 mm and a guard electrode having an inner diameter of 38 mm and an outer diameter of 50 mm are provided by a Pt—Pd vapor deposition film. The Pt—Pd vapor deposition film can be obtained by performing a vapor deposition operation for 2 minutes with mild sputtering E1030 (manufactured by Hitachi, Ltd.). The sample after the vapor deposition operation is used as a measurement sample.

The measurement atmosphere is 23 ° C./55% RH, and the measurement sample is previously left in the same atmosphere for 12 hours or more. The measurement is performed with a discharge of 10 seconds, a charge of 30 seconds, and a major of 30 seconds, and the measurement is performed at an applied voltage of 100V. Further, the applied voltage is raised or lowered as necessary.
<Thickness measurement method>
The thickness unevenness of the intermediate transfer belt of the present invention was measured over the entire circumference at four points at equal intervals in the circumferential direction about 50 mm from the both ends of the belt in a dial gauge having a minimum value of 1 μm. The average value of a total of 15 points was taken as the film thickness of the belt.

Polyethylene naphthalate resin (TN-8065S made by Teijin Chemicals) 81% by mass
Polyetheresteramide resin (Pelestat 6321 manufactured by Sanyo Chemical) 19% by mass
Each of the above materials was melted and kneaded by a biaxial extruder, and then pelletized. This was designated as molding raw material 1. Further, a preform was produced using an injection molding machine shown in FIG. Further, the injection molding machine used is not limited to the one shown in FIG. After the resin material is completely melted at 290 ° C., metering / compression / injection is performed with an injection screw, and the resin material is injected into a molding die. After holding the pressure, a cooling process is performed in the die, and then the molded product. The preform was obtained.

  Thereafter, the obtained preform was uniformly heated to 145 ° C. with a halogen heater, and then transferred to a stretch blow step. Here, the heating temperature of the preform is measured with a radiation thermometer 5 seconds before the blow mold 108 is tightened, and when the length of the preform in the longitudinal direction of the preform is 100%, the preform is heated from the center of the preform. The average value of the temperature (° C.) at a position of 40% toward the preform mouth portion and the temperature (° C.) at a position of 40% from the preform central portion toward the preform bottom portion was used.

  Next, immediately after the stretch blow molding, the molded product was taken out from the mold to obtain a desired bottle-shaped molded body. At this time, the temperature of the cylindrical mold is adjusted to 60 ° C., and there is no undulation in the molded product after blow molding, and the Sm and Rz values in the surface roughness meter are very good and at a level that cannot be measured. there were.

  Thereafter, the bottle-shaped molded body was cut to a desired size by an ultrasonic cutter with a belt width of 280 mm to obtain a seamless intermediate transfer belt-shaped intermediate transfer body. This was designated as an intermediate transfer belt (1). The final shape dimension 180 was 140 mm in diameter and 140 μm in thickness. Further, the stretch blow ratio at this time was 11.1 times as a value obtained by multiplying the stretch blow longitudinal ratio 3.0 times and the radial stretch ratio 3.7 times.

The intermediate transfer belt (1) had an electric resistance of 9.2 × 10 ⁹ Ωcm when 100 V was applied. Moreover, the elasticity modulus by a tensile test was 2100 MPa, and showed a high elasticity modulus.

  As a result of measuring the film thickness at 15 points in the circumferential direction of the belt with a dial gauge, the belt film thickness was 140 μm ± 2.8%, which was good with little film thickness unevenness. Further, 60 solid black images were measured with a Macbeth densitometer, and as a result, the density was well within the range of the average value ± 0.1. Furthermore, it is attached to the full-color electrophotographic apparatus shown in FIG. 11 as an intermediate transfer belt, and a continuous endurance test of continuous 50,000-sheet printout of A4 full-color images at a speed of 4 sheets per minute in an environment of 40 ° C./90%. went. The spring pressure of the tension roller at this time is 20 N in total in the left and right, the slide amount is 2.5 mm, and the diameters of the tension roller and the driving roller are 28 mm.

After durability, blue and green character images and line images were printed on 80 g / m ² paper using two colors, cyan and magenta, and cyan and yellow, respectively. When each image was visually observed, no color shift was observed and the running property was also good. The evaluation results are shown in Table 1.

  Stretch blow molding was performed in the same manner as in Example 1 except that the temperature control of the cylindrical type was set to 100 ° C., to obtain an intermediate transfer belt (2). The evaluation results are shown in Table 1.

  Stretch blow molding was performed in the same manner as in Example 1 except that the temperature control of the cylindrical type was 144 ° C., to obtain an intermediate transfer belt (3). The evaluation results are shown in Table 1.

  The belt obtained in Example 2 was incorporated into a full-color electrophotographic apparatus shown in FIG. The evaluation results are shown in Table 1.

  The belt obtained in Example 2 was incorporated into a full-color electrophotographic apparatus shown in FIG. 13 for evaluation as an intermediate transfer belt. The evaluation results are shown in Table 1.

Polyethylene terephthalate resin (Mitsui PET J 125) 80% by mass
Polyetherester resin (Toray DuPont 4047X 08) 20% by mass
Except for changing the composition of the above raw materials and setting the preform heating temperature to 95 ° C. and adjusting the temperature of the cylindrical mold to 50 ° C., stretch blow molding was performed in the same manner as in Example 1, and the diameter was 140 mm, the belt width was 280 mm, and the thickness was An intermediate transfer belt (4) of 120 μm was obtained. The obtained belt member was incorporated into a full-color electrophotographic apparatus shown in FIG. 11 as an intermediate transfer belt for evaluation. The evaluation results are shown in Table 1.

Except that the temperature of the cylindrical mold was adjusted to 94 ° C., stretch blow molding was performed in the same manner as in Example 1 to obtain an intermediate transfer belt (5). The obtained belt member was incorporated into a full-color electrophotographic apparatus shown in FIG. 11 as an intermediate transfer belt for evaluation. The evaluation results are shown in Table 1.
(Comparative Example 1)
In Example 1, stretch blow molding was performed in the same manner as in Example 1 except that the cylindrical mold temperature was adjusted to 170 ° C. to obtain a comparative intermediate transfer belt (1). Next, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
(Comparative Example 2)
In Example 1, stretch blow molding was performed in the same manner as in Example 1 except that the cylindrical mold temperature was adjusted to 153 ° C. to obtain a comparative intermediate transfer belt (1). Next, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
(Comparative Example 3)
In Example 5, stretch blow molding was performed in the same manner as in Example 5 except that the cylindrical mold temperature was adjusted to 140 ° C. to obtain a comparative intermediate transfer belt (2). Next, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.
(Comparative Example 4)
In Example 1, stretch blow molding was performed in the same manner as in Example 1 except that the cylindrical mold temperature was adjusted to 101 ° C. to obtain a comparative intermediate transfer belt (3). Next, the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.

<Evaluation criteria>
(Swell of molded product)
When the result measured by the surface roughness meter under the above-mentioned measurement conditions is an average wavelength (Sm) of less than 7 mm and the average wave height is 20 μm or less (Rz), the undulation outside the range is x. did.

(Concentration uniformity)
Solid black image measured with a Macbeth densitometer at 60 points, and the value outside the range of the average value ± 0.1 is within 15 points: ○, 16-30 points: Δ, 31 points or more: ×, density uniformity Was evaluated. The results are shown in Table 2.

(Thickness accuracy)
Measure the film thickness at 12 points in the belt circumferential direction and the axial direction with a dial gauge, and the difference between the maximum and minimum values and the average film thickness is within 3% of the average film thickness. The film thickness accuracy was evaluated with ◯ within 5%, over 5%, △ over 8%, and x over 8%. The results are shown in Table 1. In the measurement, the circumferential direction is measured from the center of the belt, and the axial direction is an axial straight line that passes through the circumferential measurement start point at 12 points at regular intervals.

(Durable image characteristics)
The electrophotographic belt is mounted on the full-color electrophotographic apparatus shown in FIG. 11 or 12 or 13 and subjected to a continuous durability test of 50,000 sheets of A4 size at 40 ° C./90%, and then 80 g / m ^2. Blue and green character images and line images were printed on paper using two colors, cyan and magenta, and cyan and yellow, respectively.

Each image after endurance was visually judged and evaluated for color misregistration, and it was set as ◯: good, Δ: generally good, and x: poor. Table 1 shows the evaluation results.

It is a figure which shows schematic structure of the cylindrical metal mold | die in the blow molding of this invention. It is a figure which shows schematic structure of the vertically divided metal mold | die in blow molding. It is a figure which shows schematic structure of the cylindrical metal mold | die in the blow molding of this invention. It is a figure which shows schematic structure of the preform and heater position of this invention. It is the schematic of preform preparation by injection molding. It is the schematic of the preform uniform heating by a heater. It is explanatory drawing of uniform stretch blow molding. It is explanatory drawing of uniform stretch blow molding. It is the schematic of taking out an injection stretch blow molded article. It is the schematic of removal of the both ends of an injection stretch blow molded product. 1 shows a schematic configuration of a four-process full-color image forming apparatus using an electrophotographic seamless belt of the present invention as an intermediate transfer belt. 1 is a schematic configuration of a quadruple photosensitive type full-color image forming apparatus using an electrophotographic seamless belt of the present invention as an intermediate transfer belt. 1 shows a schematic configuration of a full-color image forming apparatus using a seamless belt for electrophotography of the present invention as a transfer conveyance belt. It is a figure which shows an example of an injection molding machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Primary charger 3 Exposure light 5 Intermediate transfer belt 6 Primary transfer roller 7 Secondary transfer roller 8 Secondary transfer counter roller 9 Cleaning charging member 10 Transfer material guide 11 Paper feed roller 12 Tension roller 13 Cleaning device 15 Fixing Devices 30, 31, 33 Bias power source 32 Primary charger power source 41 Yellow color developing device 42 Magenta color developing device 43 Cyan color developing device 44 Black color developing device 51 Photosensitive belt 52 Drive roller 53 Driven roller

Claims (1)

  A step of forming a preform by injection molding a thermoplastic resin mixture, a step of heating the formed preform, a step of first stretching the preform with a stretching rod in a mold, and blowing a gas An electrophotographic seamless belt manufactured by an injection stretch blow molding method having a step of secondary stretching by the electrophotographic method, wherein a mold for stretch blow molding is adjusted to a temperature below the heating temperature of the preform For producing a seamless belt for use in an automobile.

Images