JP2011224451A - Elastic roller manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an elastic roller for electrophotography that has high shape accuracy, by preventing materials from adhering to a workpiece holding shaft for holding a shaft core and the shaft core itself, in such a manner that prevents the materials from leaking out of an annular coating head, even in a forming standby mode.SOLUTION: The method for manufacturing a plurality of elastic rollers for electrophotography each having an elastic layer at an outer circumference of the shaft core is configured to arrange the shaft core coaxially with the annual coating head having an annual slit in an inner circumference of a center hole, and to relatively move the shaft core and the annular slit, while delivering uncured rubber mixture from the annular slit. The method includes a process of relatively moving a disk, which has an outer diameter larger than the center hole diameter of the annual coating head and is formed of elastic materials insertably to the center hole of the annular coating head, and the annular coating head, thereby scraping the uncured rubber mixture in the vicinity of the annular slit using the disk.

Description

  The present invention relates to a method for manufacturing an elastic roller used in an electrophotographic apparatus.

  In recent years, in order to meet the demand for higher image quality for electrophotographic images, high accuracy from various viewpoints has been demanded for elastic rollers used for developing rollers, charging rollers, and the like. . By the way, in Patent Document 1, as one method for producing an electrophotographic elastic roller, an elastic layer material is ejected from the annular slit of an annular coating head having an annular slit opened on the inner periphery thereof, thereby A method is disclosed in which an elastic layer is formed by coating on a peripheral surface and curing the elastic layer material. Further, Patent Document 1 describes that, after the elastic layer material for one elastic roller is discharged, the elastic layer material attached to the discharge port of the annular slit is removed using a ring-shaped member. .

JP 2007-130589 A

  However, according to studies by the present inventors, even if the elastic layer material remaining at the discharge port of the annular slit is removed, the elastic layer material remaining inside the annular slit starts the next discharge. There was a case of leaking during the waiting period. Such leakage may adhere to the shaft core to which the elastic layer material is applied next, the holding shaft of the shaft core, etc., and deteriorate the shape accuracy of the elastic roller to be molded next. there were.

  Therefore, an object of the present invention is to leak the elastic layer material from the annular slit during the intermittent discharge standby when manufacturing a plurality of elastic rollers by intermittently discharging the elastic layer material using the annular coating head. An object of the present invention is to provide a method of manufacturing an elastic roller that can suppress the occurrence of a protrusion and suppress variations in quality among a plurality of elastic rollers.

In the elastic roller manufacturing method according to the present invention, an axial core body is disposed substantially concentrically with an annular coating head having an annular slit on the inner peripheral surface of the center hole, and an uncured rubber mixture is discharged from the annular slit. The shaft core body and the annular slit are relatively moved to form a coating layer of the uncured rubber mixture on the outer peripheral surface of the shaft core body, and then the shaft is cured by repeating the step of curing the coating layer. An elastic roller manufacturing method for manufacturing a plurality of electrophotographic elastic rollers having an elastic layer on an outer periphery of a core body,
The step includes a step of cleaning the annular slit,
In the cleaning step, a disk formed of an elastic material having an outer diameter larger than the diameter of the center hole of the annular coating head and insertable into the center hole of the annular coating head, and the annular coating head And a step of scraping the uncured rubber mixture in the vicinity of the annular slit with the disc.

  According to the present invention, it is possible to obtain a plurality of elastic rollers with little variation in shape.

It is a schematic block diagram which shows an example of the coating device applied to formation of the coating layer of this invention. It is a schematic sectional drawing which shows an example of the cyclic | annular coating head which can be used for this invention. It is a figure explaining the conventional process of forming a coating layer in the outer peripheral surface of a shaft core. It is a figure explaining the mechanism in which the shape accuracy of an elastic roller deteriorates when an uncured rubber mixture adheres to a work holding shaft. It is a figure explaining the disk which concerns on this invention. It is explanatory drawing of the manufacturing method of the elastic roller which concerns on this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus.

  A schematic configuration of a coating apparatus having an annular coating head is shown in FIG. In the coating apparatus shown in FIG. 1, a column 2 is attached substantially vertically on a gantry 1, and a precision ball screw 3 is attached to the column 2 substantially vertically. Two linear guides 4 are attached to the column 2 in parallel with the precision ball screw 3. The LM guide 5 is connected to the linear guide 4 and the precision ball screw 3, so that the rotary motion is transmitted from the servo motor 6 through the pulley 7 so that the LM guide 5 can move up and down. An annular coating head 9 that discharges an uncured rubber mixture is attached to the column 2 on the outer peripheral surface of a cylindrical shaft core body 8. Further, a bracket 10 is attached to the LM guide 5, and a work lower holding shaft 11 and a work upper holding shaft 12 for holding the shaft core body 8 are attached to the bracket 10.

  The center of the center hole of the annular coating head 9 and the shaft centers of the workpiece lower holding shaft 11 and the workpiece upper holding shaft 12 are adjusted to be substantially concentric, and the inner peripheral surface of the annular coating head and the shaft core 8 are adjusted. A uniform gap is formed between the outer peripheral surfaces of the two.

  The uncured rubber mixture supply port 13 is connected to a material supply valve 15 via a pipe 14 for conveying the uncured rubber mixture. The material supply valve 15 is provided with a mixing mixer, a material supply pump, a material fixed amount discharge device, a material tank, and the like in front of it, so that a fixed amount of uncured rubber mixture can be discharged. An uncured rubber mixture is weighed from a material tank by a material dispensing device and mixed by a mixing mixer. Thereafter, the uncured rubber mixture is sent from the material supply valve 15 to the annular coating head 9 via the pipe 14 by the material supply pump.

  FIG. 2 is a schematic sectional view of an example of an annular coating head. The annular coating head has an annular slit 18 on the inner peripheral surface 17 of the center hole 16, and an uncured rubber mixture is discharged from an opening 19 of the annular slit 18. The width of the annular slit is usually set to 0.5 or more and 2.0 mm or less.

  Next, a conventional process for forming a coating layer on the outer peripheral surface of the shaft core body using the annular coating head will be described with reference to FIG. At the time of molding standby, the workpiece holding shaft is waiting in a state where it is coming out from the rear in the moving direction of the annular coating head (the direction indicated by the white arrow in FIG. 3) ((a) in FIG. 3). After the shaft core passed through the center hole of the ring-shaped member is held by the work holding shaft and the work lower holding shaft ((b) in FIG. 3), the shaft core, the work holding shaft and the work lower holding shaft are provided. Is moved forward in the moving direction. Then, the ring-shaped member 20 is pushed into the annular coating head by the holding shaft on the workpiece, and the ring-shaped member 20 is mounted at a position ahead of the moving direction from the opening of the annular slit opened on the inner peripheral surface of the annular coating head (see FIG. (C) of 3).

  The outer diameter of the ring-shaped member is preferably the same as the diameter of the central hole of the annular coating head so that the outer peripheral surface thereof can contact the inner peripheral surface of the central hole of the annular coating head. As a result, the ring-shaped member does not move due to the discharge pressure of the rubber mixture discharged from the annular slit, and the ring-shaped member can be firmly held at a position ahead of the moving direction from the opening of the annular slit.

  After moving the shaft core, workpiece upper holding shaft and workpiece lower holding shaft to the coating start position ((d) in FIG. 3), the uncured rubber mixture fed to the annular coating head is discharged from the annular slit. To do. In order to make the thickness of the rubber mixture constant, the discharge amount from the annular slit and the supply amount from the material supply pump are made constant. Cylindrical coating made of uncured rubber mixture on the outer peripheral surface of the shaft core body by discharging the uncured rubber mixture and moving the shaft core body, workpiece holding shaft and workpiece lower holding shaft vertically upward Layer 21 is formed ((e) of FIG. 3). During the discharge of the uncured rubber mixture, only the shaft core body moves, and the ring-shaped member is held at the position in front of the moving direction from the opening of the annular slit, so that the discharged uncured rubber mixture is annularly coated. It is possible to prevent leakage from the front of the working head in the moving direction. In FIG. 3, the annular coating head is fixed and the shaft core body is moved upward in the vertical direction. However, the annular coating head can be moved by fixing the shaft core body. That is, by moving the annular coating head relative to the shaft core body, the cylindrical coating layer 21 made of an uncured rubber mixture can be formed on the outer peripheral surface of the shaft core body.

  The shaft core on which the coating layer is formed is pushed out together with the ring-shaped member from the annular slit to the rear in the moving direction by the work lower holding shaft ((f) in FIG. 3). At this time, since the outer diameter of the ring-shaped member is the same as the diameter of the center hole of the annular coating head, the uncured rubber mixture on the inner peripheral surface of the annular coating head is scraped off.

  The shaft core body and ring-shaped member on which the coating layer extruded from the annular coating head is formed are removed from the workpiece holding shaft and the workpiece lower holding shaft, and cured by heat treatment to form an elastic layer. On the other hand, in the coating apparatus, the workpiece lower holding shaft protrudes from the rear in the moving direction of the annular coating head until the shaft core and the ring-shaped member used for the next molding are newly held by the workpiece holding shaft and the workpiece lower holding shaft. And is waiting (Fig. 3 (a)).

  However, in a normal manufacturing method in which a plurality of elastic rollers are formed, the uncured rubber mixture in the annular slit is expanded from the compression at the time of discharge during this waiting period, or remains after the completion of the discharge. The flow of uncured rubber mixture may leak from the annular slit. As a result, the uncured rubber mixture leaking from the annular slit adheres to the workpiece holding shaft, the workpiece lower holding shaft, and the shaft core itself, causing deterioration of the shape accuracy of the next-formed elastic roller. A mechanism in which the shape accuracy of the elastic roller is deteriorated when an uncured rubber mixture adheres to the workpiece holding shaft and the workpiece holding shaft will be described with reference to FIG.

  The uncured rubber mixture in the annular slit causes the above-mentioned factors while waiting for the shaft core with the coating layer and the ring-shaped member to be removed from the workpiece holding shaft and the workpiece lower holding shaft until the next molding starts. To leak from the annular slit ((a) of FIG. 4). When the ring-shaped member is pushed into the annular coating head by the holding shaft on the workpiece and the ring-shaped member is mounted at a position ahead of the annular slit in the moving direction, the uncured ring-shaped member leaked from the annular slit. The rubber mixture is scraped off ((b) of FIG. 4). When the shaft core on which the coating layer is formed is pushed together with the ring-shaped member by the holding shaft under the workpiece from the annular slit to the rear in the moving direction, the uncured material is scraped by the ring-shaped member in the step (b) of FIG. The ring-shaped member and the workpiece lower holding shaft are brought into close contact with each other through the rubber mixture ((c) in FIG. 4). In this state, if the shaft core formed with the coating layer and the ring-shaped member are removed from the workpiece lower holding shaft, the ring member and the workpiece lower holding shaft are in close contact with each other by the uncured rubber mixture. The coating layer near the shaped member is pulled downward and deforms ((d) in FIG. 4).

  In order to solve the above-described problems, the present invention includes a step of cleaning the annular slit during the series of steps described above. In the cleaning process, a disk and an annular coating head, which have an outer diameter larger than the diameter of the central hole of the annular coating head, and are made of an elastic material so as to be inserted into the central hole of the annular coating head. This is done by scraping the uncured rubber mixture in the vicinity of the annular slit with the disc by moving it relatively.

    In the present invention, by making the outer diameter of the disk larger than the diameter of the center hole of the annular coating head, not only the inner peripheral surface of the annular coating head but also the uncured rubber mixture inside the annular slit can be scraped off. it can. Even if the uncured rubber mixture expands or is pushed out by the remaining flow during standby for the next molding, it does not leak out from the annular slit. The outer diameter of the disk is preferably 0.2 mm or more and 2.0 mm or less larger than the diameter of the center hole of the annular coating head. When the size is less than 0.2 mm larger than the diameter of the center hole of the annular coating head, the amount of the uncured rubber mixture scraped off inside the annular slit decreases, and a small amount of uncured rubber mixture from the annular slit during molding standby. However, it may leak out. On the other hand, if it is larger than 2.0 mm, the disk may be inserted obliquely when inserted into the center hole of the annular coating head, and the outer periphery of the disk will not be in uniform contact with the inner peripheral surface of the annular coating head. Sometimes.

  Further, by forming the disk from an elastic material, even if the outer diameter of the disk is larger than the diameter of the center hole of the annular coating head, the disk can be distorted and inserted into the annular coating head. On the other hand, since it returns to the original shape again when it is released from the pressure from the surroundings as in the annular slit portion, the uncured rubber mixture can be scraped off to the inside of the annular slit.

  The material of the disk is not particularly limited as long as it has elasticity, but a synthetic resin that does not damage the annular coating head is preferable. Examples of the synthetic resin include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polymethyl methacrylate, polyamide, polycarbonate, polyimide, and fluororesin.

The cleaning process may be performed between any processes, but before the coating apparatus is waiting and the uncured rubber mixture leaks from the annular slit, that is, the shaft core body and the ring-shaped member on which the coating layer is formed Is preferably performed after the workpiece is removed from the workpiece holding shaft and the workpiece lower holding shaft.
The direction in which the disk is inserted into the center hole of the annular coating head only needs to pass through the opening of the annular slit, and may be inserted from either of the annular coating heads. In addition, as a method of inserting the disc into the center hole of the annular coating head, a shaft for inserting the disc may be newly added to the coating device, but it is held on the workpiece used when a ring-shaped member is inserted. An axis or a workpiece holding axis can also be used.

  As for the shape of the disc, the inner peripheral surface of the annular coating head and the uncured rubber mixture inside the annular slit are scraped off at the outer peripheral portion of the disc, so that the center portion of the disc may have a hole. Further, it may be a circular and flat one with a uniform thickness, but it is more preferable if there is a bowl-like warp with a raised central portion. When using a bowl-shaped disk, the raised part of the central part is inserted into the center hole of the annular coating head first, so that the outer peripheral part of the annular coating head is more flat than the flat disk. It becomes easy to contact the inner peripheral surface uniformly without a gap. FIG. 5 shows an example of a bowl-shaped disk having a raised central portion. In the example of FIG. 5, the bowl-shaped disk has a shape obtained by cutting out a part of a sphere having an outer peripheral radius SR2 and an inner peripheral radius SR1.

  Also, if the outer circumference side is greatly distorted from the inner circumference side of the disk, the workpiece holding shaft or the workpiece lower holding shaft comes into contact with the inner circumference side of the disc evenly in the circumferential direction, and the disc is Insertion at an angle can be prevented. In order to distort the outer peripheral side from the inner peripheral side of the disk, it is preferable to change the material on the inner peripheral side and the outer peripheral side of the disk so that the inner peripheral material has a smaller bending strain than the outer peripheral material. If the thickness is the same on the inner and outer peripheral sides of the disk, the bending strain may be determined from the bending elastic modulus of each material.

  Even in the case of a bowl-shaped disc, the inner portion of the circle with the radius r1 is formed of a relatively hard material in the horizontal direction from the center point O of the disc in the example of FIG. 5, and the circle with the radius r2 outside the circle with the radius r1. The inner part of the substrate may be formed of a relatively soft material. If the material on the inner peripheral side is made smaller in bending strain than the material on the outer peripheral side, the outer peripheral side can be preferentially distorted to prevent the disk from being inserted obliquely, so the range of r1 and r2, or r1 The ratio of r2 is not particularly limited.

  Further, in the present invention, it is not necessary to newly add a cleaning process by using the disk as a ring-shaped member. Therefore, the molding step of the present invention includes (1) a step of inserting the disk into the center hole of the annular coating head from the front of the annular coating head in the moving direction, and mounting the disc at a position forward of the moving direction from the opening of the annular slit (2) forming a coating layer of the uncured rubber mixture on the peripheral surface of the shaft core body by relatively moving the shaft core body and the annular slit while discharging the uncured rubber mixture from the annular slit; (3 ) It is achieved by moving the disk backward in the moving direction of the annular coating head to scrape off the uncured rubber mixture in the vicinity of the annular slit and taking it out from the rear in the moving direction of the annular coating head.

  A series of steps when the disk is also used as a ring-shaped member will be described in detail with reference to FIG. In the step (1), the shaft core through which the disk 22 is passed instead of the ring-shaped member is held by the work holding shaft and the work lower holding shaft so that the disk 22 is in front of the moving direction of the annular coating head ( (A) of FIG. The shaft core, the workpiece upper holding shaft and the workpiece lower holding shaft are moved rearward in the movement direction, and the movement direction from the opening of the annular slit opened on the inner peripheral surface of the center hole of the annular coating head using the workpiece lower holding shaft. The disc 22 is mounted at the front position ((b) of FIG. 6). After moving the shaft core, the workpiece upper holding shaft and the workpiece lower holding shaft to the coating start position ((c) in FIG. 6), the uncured rubber fed to the annular coating head in the step (2) The mixture is discharged from the annular slit ((d) in FIG. 6). In the step (3), after the discharge of the uncured rubber mixture to the outer peripheral surface of the shaft core body is completed, the shaft core body on which the coating layer has been formed is moved together with the disk 22 from the annular slit to the rear side in the movement direction. (Fig. 6 (e)). Since the outer diameter of the disk 22 is larger than the diameter of the center hole of the annular coating head and is made of an elastic material, at the opening of the annular slit, it returns to its original shape and at the same time, an uncured rubber mixture inside the annular slit. Scrape off. The shaft core body and the ring-shaped member on which the coating layer extruded from the annular coating head is formed are removed from the workpiece holding shaft and the workpiece lower holding shaft ((f) in FIG. 6), and cured by heat treatment. It becomes an elastic layer.

  The coating layer formed on the outer peripheral surface of the shaft core body becomes an elastic layer by being cured. Since the coating layer has adhesiveness, it is preferable to perform the heat treatment by a non-contact heat treatment method. Examples of the non-contact heat treatment method include an infrared heating method, a hot air heating method, a nichrome heat heating method, and the like. In particular, infrared heating is preferred because the apparatus is simple and the coating layer can be uniformly heat-treated in the axial direction. The heat treatment temperature on the surface of the coating layer depends on the rubber mixture to be used. When infrared heating is performed, the output of the infrared heating device and the distance from the coating layer may be adjusted according to the heat treatment temperature. Moreover, what is necessary is just to adjust the temperature and direction of a hot air when performing hot air heating. Further, the elastic layer formed by curing for the purpose of stabilizing physical properties after curing of the elastic layer and removing reaction residues and unreacted low molecular components in the elastic layer may be further heat-treated and secondarily cured.

  Examples of the material constituting the shaft core include the following materials. Alloys of iron, steel, aluminum, titanium, copper and nickel, stainless steel containing these metals, alloys of duralumin, brass and bronze, as well as composite materials in which carbon black and carbon fibers are solidified with plastic are known to exhibit rigidity and conductivity. Material. Further, the shape may be a columnar shape or a cylindrical shape having a hollow at the center.

The rubber component to be contained in the rubber mixture forming the elastic layer is not particularly limited, but it is preferable to use an addition reaction type silicone rubber for the following reasons.
・ Low compression set despite low hardness compared to other general-purpose rubber.
・ Excellent workability.
-Good dimensional stability due to the absence of by-products associated with the curing reaction.
-The physical properties after curing are stable.

  The addition-type liquid silicone rubber is cured by an addition reaction between an alkenyl group-containing polysiloxane and a hydrosilyl group-containing hydrogen polysiloxane in the presence of a platinum catalyst.

  Although it does not specifically limit as molecular weight of the polysiloxane containing an alkenyl group, 10,000 or more and 500,000 or less are preferable. It is desirable that the polysiloxane has at least two alkenyl groups in one molecule. Although the kind of alkenyl group is not particularly limited, at least one of a vinyl group and an allyl group is preferable, and a vinyl group is particularly preferable because of its high reactivity with active hydrogen.

  In addition, the molecular weight in this invention is a weight average molecular weight when measured by gel permeation chromatography (GPC). That is, toluene as a solvent was allowed to flow through a column stabilized in a 40 ° C. heat chamber at a flow rate of 0.5 ml per minute, and 50 to 200 μl of a sample solution adjusted to 0.1 to 0.3% by mass was injected. And the weight average molecular weight of the sample was computed from the calibration curve created with several types of monodisperse polystyrene standard samples.

  The hydrogen polysiloxane containing a hydrosilyl group serves as a crosslinking agent for the addition reaction in the curing process. The number of silicon-bonded hydrogen atoms in one molecule is 2 or more, and preferably 3 or more in order to optimally carry out the curing reaction. The molecular weight of the hydrogen polysiloxane is not particularly limited, but is preferably 1000 or more and 10,000 or less, and particularly preferably 1000 or more and 5000 or less with a relatively low molecular weight in order to appropriately perform the curing reaction.

  The blending amount of the hydrogenpolysiloxane of the addition type liquid silicone rubber in the present invention is such that the number of hydrosilyl groups in the hydrogenpolysiloxane is 1.0 to 3.0 times the number of alkenyl groups in the polysiloxane. It is preferable that If it is less than 1.0 times, the crosslinking of the silicone rubber is reduced and the compression set may be deteriorated. On the other hand, when it exceeds 3.0 times, excessively unstable hydrosilyl groups remain, which is not preferable because the hardness and current of the electrophotographic elastic roller may change over time.

  As the catalyst for the addition-type liquid silicone rubber, a platinum catalyst that exhibits a catalytic action in the addition reaction of polysiloxane and hydrogen polysiloxane can be used. Specific examples thereof include chloroplatinic acid, platinum olefin complexes, platinum vinylsiloxane complexes, and platinum triphenylphosphine complexes.

  Regarding the blending amount of the catalyst, the platinum element amount is preferably 1 ppm or more and 1000 ppm or less with respect to 100 parts by mass of the polysiloxane. However, it is not limited to this range, and is appropriately selected depending on the target pot life, curing time, product shape, and the like.

  Conductive agents added for the purpose of imparting conductivity to the elastic layer include carbon black, graphite, conductive metal oxides, copper, aluminum, nickel, iron powder, or alkali metal salts that are ionic conductive agents, and ammonium salts. These fine particles can also be used. Among these, carbon black can be suitably used because it is relatively easily available.

  Furthermore, according to the specific use of the electrophotographic elastic roller, a non-conductive filler can be appropriately blended as a component necessary for the function required for the elastic layer itself. Non-conductive fillers include diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, zirconium silicate, aluminum silicate, talc, alumina and iron oxide.

  In this invention, the coating layer according to a use can also be provided on the outer periphery of the elastic layer formed as mentioned above. Examples of the material for forming the coating layer include various polyamides, fluororesins, hydrogenated styrene-butylene resins, urethane resins, silicone resins, polyester resins, phenol resins, imide resins, and olefin resins.

  In the coating layer, fine particles having a volume average particle diameter of 1 to 20 μm can be dispersed in accordance with individual applications. Examples of such fine particles include polymethyl methacrylate fine particles, silicone rubber fine particles, polyurethane fine particles, polystyrene fine particles, amino resin fine particles, and phenol resin fine particles.

  The coating layer may contain a conductive agent in order to adjust the electric resistance of the entire electrophotographic elastic roller. Conductive agents include carbon black, graphite, conductive metal oxides, copper, aluminum, nickel, iron powder, or alkali metal salts that are ionic conductive agents, and ammonium salts, which are conductive agents having various electron conduction mechanisms. Can be used.

  The material constituting these coating layers can be dispersed using a conventionally known dispersion apparatus using sand mill, paint shaker, dyno mill, or pearl mill beads. A method for coating the obtained dispersion is not particularly limited, but a spray coating method or a dipping method is preferable because the operation is simple.

Next, an example of an image forming apparatus having the electrophotographic elastic roller of the present invention will be described with reference to FIG.
The image forming apparatus shown in FIG. 7 has four electrophotographic cartridges 23 for forming yellow, cyan, magenta and black images, respectively, and is provided in a tandem manner.

  The developing device 24 includes a developing roller 26 disposed opposite to the photosensitive drum 25 and a developing container 28 containing a developer 27. Further, the developer 27 is supplied to the developing roller 26 and scrapes off the developer 27 that is not used for development and remains on the developing roller 26. A developing blade 30 that regulates and frictionally charges is provided.

  The photosensitive drum 25 is uniformly charged to a predetermined polarity and potential by the charging roller 31. According to the image information, the surface of the charged photosensitive drum 25 is irradiated with the beam 32, and an electrostatic latent image is formed. Next, the developer 27 uniformly coated on the developing roller 26 by the bias applied to the developing blade 30 on the formed electrostatic latent image is supplied from the developing roller 26, and the developer image is formed on the surface of the photosensitive drum 25. It is formed. Here, the bias applied to the developing blade 30 is generally a voltage several hundred volts higher than the bias of the developing roller 26.

  In the image transfer apparatus, a transfer conveyance belt 33 is stretched around a driving roller 34, a tension roller 35, and a driven roller 36, and a transfer roller 37 is installed inside the transfer conveyance belt 33 at a position facing the photosensitive drum 25. . Then, by applying a bias to the electrostatic adsorption roller 38, the transfer material 39 is electrostatically adsorbed to the outer peripheral surface of the transfer conveyance belt 33 and conveyed. When the transfer material 39 is conveyed to the transfer position, a bias having a polarity opposite to that of the developer image on the surface of the photosensitive drum 25 is applied to the transfer roller 37. As a result, the developer image is transferred to the transfer material 39. The transfer material 39 onto which the developer image has been transferred is sent from the transfer conveyance belt 33 to the fixing device 40, where the developer image is fixed on the transfer material 39, and printing is completed. On the other hand, the photosensitive drum 25 after the transfer of the developer image to the transfer material 39 is further rotated, and the surface of the photosensitive drum 25 is cleaned by the cleaning device 41.

  The electrophotographic elastic roller of the present invention can be used for the developing roller, charging roller, and transfer roller. In addition to the image forming apparatus described above, the image forming apparatus can be used for an intermediate transfer type image forming apparatus.

  The present invention will be described more specifically with reference to the following examples. The present invention is not limited to the following examples.

<Example 1>
[Molding of elastic layer]
10 parts by mass of carbon black (Raven 890 manufactured by Columbian Chemical) was added to each 100 parts by mass of liquid A and liquid B of addition type liquid silicone rubber (XE15-645 manufactured by Momentive Performance Materials Japan GK). Liquid A and liquid B were set in a material tank attached to the coating apparatus and sent to a static mixer using a material supply pump, and liquid A and liquid B were mixed at a mass ratio of 1: 1. This was a rubber mixture.

  For forming the elastic layer, the coating apparatus shown in FIG. 1 was used. The diameter of the center hole of the annular coating head was 12.60 mm, and the width of the annular slit was 1.0 mm. The shaft core of SUS304 having a diameter of 6.0 mm and a length of 250.0 mm has a hollow disc shape with an inner diameter of 6.2 mm, an outer diameter of 12.6 mm, a thickness of 1.0 mm, and a material made of polytetrafluoroethylene. The shaft core was held by the workpiece holding shaft and the workpiece lower holding shaft so that the ring member passed through the ring coating member. Next, the shaft core, the workpiece upper holding shaft, and the workpiece lower holding shaft were moved downward, and a ring-shaped member was mounted under the opening of the annular slit using the workpiece upper holding shaft.

After moving the shaft core, the workpiece upper holding shaft and the workpiece lower holding shaft to the coating start position, the uncured rubber mixture fed to the annular coating head is discharged from the annular slit at a flow rate of 840 mm ³ / sec. At the same time, the workpiece upper holding shaft and the workpiece lower holding shaft were raised from below to above at a speed of 10 mm / sec to form a coating layer on the outer peripheral surface of the shaft core.

  Even after the discharge of the uncured rubber mixture, the workpiece holding shaft and the workpiece holding shaft were moved, and the shaft core and the ring-shaped member on which the coating layer was formed were pushed out onto the annular coating head. The shaft core body and the ring-shaped member formed with the coating layer extruded from the annular coating head were removed from the workpiece holding shaft and the workpiece lower holding shaft, and cured by heat treatment.

  For the heat treatment of the coating layer, an infrared heating lamp (HYL25 manufactured by Hibeck) was disposed so that the heat treatment temperature (surface temperature of the heated object) was 130 ° C. (output 780 W, distance between the lamp and the surface of the object to be cured 60 mm). . The shaft core on which the coating layer was formed was heated for 5 minutes while rotating in the circumferential direction at 60 rpm, and the coating layer was cured to form an elastic layer.

  In the coating apparatus, after removing the shaft core body and the ring-shaped member on which the coating layer is formed from the workpiece holding shaft and the workpiece lower holding shaft, the outer diameter is 12.80 mm, the thickness is 500 μm, and the material is polyacetal (POM). ) Was inserted from above the annular coating head using the workpiece holding shaft, and was moved as it was under the annular coating head to scrape off the uncured rubber mixture near the annular slit. .

  Thereafter, the shaft core and the ring-shaped member were again held by the workpiece holding shaft and the workpiece lower holding shaft, and the above steps were repeated to form a total of 500 elastic rollers.

[Measurement and evaluation of the outer diameter difference of the elastic roller in the longitudinal direction]
In order to evaluate the shape accuracy of the elastic roller, the outer diameter difference in the longitudinal direction of the elastic roller was measured. The outer diameter difference in the longitudinal direction of the elastic roller is determined by a non-contact laser length measuring device (LS-5000 manufactured by Keyence) that rotates the elastic roller around the central axis of the shaft core and is arranged perpendicular to the rotation axis. The outer diameters at two points 1 cm inside from the end in contact with the ring-shaped member at the center in the longitudinal direction are measured. The difference between the two measured outer diameters was taken as the outer diameter difference in the longitudinal direction of the elastic roller and evaluated as follows.
A: All 500 elastic rollers formed have a difference in outer diameter in the longitudinal direction of less than 50 μm. B: Of the 500 elastic rollers formed, the difference in outer diameter in the longitudinal direction is less than 50 μm. C: Molding Of the 500 elastic rollers, three or more whose longitudinal diameter difference is 50 μm or more are shown in Table 1.

<Example 2>
An elastic roller was produced and evaluated in the same manner as in Example 1 except that the outer diameter of the disk was 13.60 mm.

<Example 3>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the outer diameter of the disk was 14.60 mm and the thickness was 100 μm.

<Example 4>
The shaft core is passed through a hollow disk shaped disk with an inner diameter of 6.2 mm, an outer diameter of 12.80 mm, a thickness of 500 μm and a material of polyacetal, and the shaft core is placed under the annular coating head. It was held by the upper holding shaft and the workpiece lower holding shaft. Next, the shaft core body, the workpiece upper holding shaft, and the workpiece lower holding shaft were moved upward, and the disc was mounted under the opening of the annular slit using the workpiece lower holding shaft.

  After moving the shaft core, the workpiece upper holding shaft and the workpiece lower holding shaft to the coating start position, the uncured rubber mixture is discharged from the annular slit, and at the same time, the workpiece upper holding shaft and the workpiece lower holding shaft are raised from below. The coating layer was formed on the outer peripheral surface of the shaft core.

  Even after discharging the uncured rubber mixture, the workpiece holding shaft and the workpiece lower holding shaft are moved, and the shaft core body and disk on which the coating layer is formed are pushed out onto the annular coating head. Uncured rubber mixture was scraped off. The shaft core body and the disc on which the coating layer extruded from the annular coating head was formed were removed from the workpiece holding shaft and the workpiece lower holding shaft, and cured by heat treatment with an infrared heating lamp.

After removing the shaft core and the disk on which the coating layer is formed from the work holding shaft and the work lower holding shaft, the new shaft core again has an inner diameter of 6.2 mm, an outer diameter of 12.80 mm, a thickness of 500 μm, A new hollow disk-shaped disk made of polyacetal was passed through to the next molding.
Except for the above, an elastic roller was prepared and evaluated in the same manner as in Example 1.

<Example 5>
An elastic roller was prepared and evaluated in the same manner as in Example 4 except that the outer diameter of the disk was 13.60 mm.

<Example 6>
An elastic roller was prepared and evaluated in the same manner as in Example 4 except that the outer diameter of the disk was 14.6 mm and the thickness was 100 μm.

<Example 7>
The outer diameter of the disk is 12.80 mm, the thickness is 500 μm, and the material is polyethylene terephthalate (PET) with a bending elastic modulus of 2500 MPa from the center to the outer peripheral side of the disk to 4.30 mm. The bending elastic modulus is 900 MPa from 4.30 mm to 6.40 mm. An elastic roller was prepared and evaluated in the same manner as in Example 1 except that polyethylene (PE) was used.

<Example 8>
Example 1 except that the outer diameter of the disk is 14.60 mm, and the material is polyethylene terephthalate having an elastic modulus of 2500 MPa from the center to the outer peripheral side of the disk to 4.90 mm, and polyethylene having a bending elastic modulus of 900 MPa from 4.90 mm to 7.30 mm. In the same manner, an elastic roller was produced and evaluated.

<Example 9>
The outer diameter of the disk is 12.80 mm, the thickness is 500 μm, and the material is polyethylene terephthalate having an elastic modulus of 2500 MPa from the center to the outer periphery side of the disk from 3.10 mm to 4.30 mm, and a bending elastic modulus of 900 MPa from 4.30 mm to 6.40 mm. An elastic roller was prepared and evaluated in the same manner as in Example 4 except that polyethylene was used.

<Example 10>
The outer diameter of the disk was 14.60 mm, and the material was polyethylene terephthalate having an elastic modulus of 2500 MPa from 3.10 mm to 4.90 mm from the center of the disk to the outer peripheral side, and polyethylene having a bending elastic modulus of 900 MPa from 4.90 mm to 7.30 mm. Otherwise, an elastic roller was produced and evaluated in the same manner as in Example 4.

<Example 11>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
The shape of the disk is a bowl-shaped disk with SR1 of 20.5 mm, SR2 of 21.0 mm, and the outer diameter of the disk of 12.80 mm in FIG. There is no hole in the center. In FIG. 5, r1 is 4.30 mm, r2 is 6.40 mm, a portion in a circle having a radius r1 is made of polyethylene terephthalate having a bending elastic modulus of 2500 MPa, and outside the circle having a radius r1, The inner part of the circle with radius r2 was made of polyethylene with a flexural modulus of 900 MPa.

<Example 12>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
In FIG. 5, the shape of the disk is a bowl-shaped disk with SR1 of 26.6 mm, SR2 of 27.1 mm, and the outer diameter of the disk of 14.60 mm. There is no hole in the center. Further, in FIG. 5, r1 is 4.90 mm, r2 is 7.30 mm, a portion in a circle having a radius r1 is made of polyethylene terephthalate having a bending elastic modulus of 2500 MPa, and outside the circle having a radius r1, The inner part of the circle with radius r2 was made of polyethylene with a flexural modulus of 900 MPa.

<Example 13>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
In FIG. 5, the shape of the disk is a bowl-shaped disk having SR1 of 20.5 mm, SR2 of 21.0 mm, and an outer diameter of 12.80 mm, and a hole having an inner diameter of 6.2 mm is formed at the center of the disk. ing. In FIG. 5, r1 is 4.30 mm, r2 is 6.40 mm, a portion in a circle having a radius r1 is made of polyethylene terephthalate having a bending elastic modulus of 2500 MPa, and outside the circle having a radius r1, The inner part of the circle with radius r2 was made of polyethylene with a flexural modulus of 900 MPa.

<Example 14>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
In FIG. 5, the shape of the disk is a bowl-shaped disk having SR1 of 26.6 mm, SR2 of 27.1 mm, and an outer diameter of 14.60 mm, and a hole having an inner diameter of 6.2 mm is formed at the center of the disk. ing. Further, in FIG. 5, r1 is 4.90 mm, r2 is 7.30 mm, and the portion in the circle with radius r1 is made of polyethylene terephthalate having a bending elastic modulus of 2500 MPa, and outside the circle with radius r1. The inner part of the circle with radius r2 was made of polyethylene having a flexural modulus of 900 MPa.

<Example 15>
An elastic roller was produced in the same manner as in Example 1 except that the shape of the disk was a bowl-shaped disk having SR1 of 20.5 mm, SR2 of 21.0 mm, and an outer diameter of the disk of 12.80 mm in FIG. evaluated.

<Example 16>
An elastic roller was produced in the same manner as in Example 1 except that the shape of the disk was a bowl-shaped disk having SR1 of 26.6 mm, SR2 of 27.1 mm, and an outer diameter of 14.60 mm in FIG. evaluated.

<Example 17>
An elastic roller was produced in the same manner as in Example 4 except that the shape of the disk was a bowl-shaped disk with SR1 of 20.5 mm, SR2 of 21.0 mm, and the outer diameter of the disk of 12.80 mm in FIG. evaluated.

<Example 18>
An elastic roller was produced in the same manner as in Example 1 except that the shape of the disk was a bowl-shaped disk having SR1 of 26.6 mm, SR2 of 27.1 mm, and an outer diameter of 14.60 mm in FIG. evaluated.

<Example 19>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
In FIG. 5, the shape of the disk is a bowl-shaped disk with SR1 of 23.8 mm, SR2 of 24.3 mm, and the outer diameter of the disk of 13.80 mm, and there is a hole with an inner diameter of 6.2 mm in the center of the disk. ing. In FIG. 5, r1 is 4.60 mm, r2 is 6.90 mm, a portion in a circle with a radius r1 is made of polyethylene terephthalate having a bending elastic modulus of 2500 MPa, and outside the circle with a radius r1, The inner part of the circle with radius r2 was made of polyethylene with a flexural modulus of 900 MPa.

<Example 20>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the outer diameter of the disk was 12.68 mm.

<Example 21>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the outer diameter of the disk was 15.10 mm and the thickness was 100 μm.

<Example 22>
An elastic roller was prepared and evaluated in the same manner as in Example 4 except that the outer diameter of the disk was 12.68 mm.

<Example 23>
An elastic roller was prepared and evaluated in the same manner as in Example 4 except that the outer diameter of the disk was 15.10 mm and the thickness was 100 μm.

<Example 24>
The outer diameter of the disk is 12.80 mm, the thickness is 500 μm, the material is polymethyl methacrylate (PMMA) with a bending elastic modulus of 3100 MPa from the center of the disk to the outer peripheral side to 4.30 mm, and the bending elastic modulus is 900 MPa from 4.30 mm to 6.40 mm. An elastic roller was prepared and evaluated in the same manner as in Example 1 except that polyethylene was used.

<Example 25>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
In FIG. 5, the shape of the disk is a bowl-shaped disk with SR1 of 26.6 mm, SR2 of 27.1 mm, and the outer diameter of the disk of 14.60 mm. There is no hole in the center. In FIG. 5, r1 is 4.90 mm, r2 is 7.30 mm, a portion in a circle with a radius r1 is made of polymethylmethacrylate having a bending elastic modulus of 3100 MPa, and outside the circle with a radius r1. The inner part of the circle having the radius r2 was made of polyethylene having a flexural modulus of 900 MPa.

<Example 26>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the following disk was used.
In FIG. 5, the shape of the disk is a bowl-shaped disk having SR1 of 20.5 mm, SR2 of 21.0 mm, and an outer diameter of the disk of 12.80 mm, and a hole having an inner diameter of 6.2 mm is formed at the center of the disk. ing. Further, in FIG. 5, r1 is 4.30 mm, r2 is 6.40 mm, and the bending elastic modulus of the portion in the circle with radius r1 is made of polymethylmethacrylate with 3100 MPa, outside the circle with radius r1. The inner part of the circle having the radius r2 was made of polyethylene having a flexural modulus of 900 MPa.

<Example 27>
The outer diameter of the disk is 14.60 mm, and the material is 3.10 to 4.90 mm from the center to the outer periphery of the disk. Polymethylmethacrylate having an elastic modulus of 3100 MPa, and 4.90 to 7.30 mm is a polyethylene having a bending elastic modulus of 900 MPa. Except that, an elastic roller was produced and evaluated in the same manner as in Example 4.

<Comparative Example 1>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the step of cleaning the annular coating head with a disk was not performed.

<Comparative example 2>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the outer diameter of the disk was 12.60 mm.

<Comparative Example 3>
An elastic roller was prepared and evaluated in the same manner as in Example 1 except that the outer diameter of the disk was 12.40 mm.

<Comparative example 4>
An elastic roller was prepared and evaluated in the same manner as in Example 4 except that the outer diameter of the disk was 12.60 mm.

<Comparative Example 5>
An elastic roller was prepared and evaluated in the same manner as in Example 4 except that the outer diameter of the disk was 12.40 mm.
The results of Examples 1 to 27 and Comparative Examples 1 to 5 are shown in Table 1 below.

Claims (4)

An axial core body is arranged substantially concentrically with an annular coating head having an annular slit on the inner peripheral surface of the center hole, and the shaft core body and the annular slit are relatively disposed while discharging an uncured rubber mixture from the annular slit. And forming an uncured rubber mixture coating layer on the outer circumferential surface of the shaft core body, and then repeating the step of curing the coating layer, thereby having an elastic layer on the outer circumference of the shaft core body. An elastic roller manufacturing method for manufacturing a plurality of elastic rollers for
The step includes a step of cleaning the annular slit,
In the cleaning step, a disk formed of an elastic material having an outer diameter larger than the diameter of the center hole of the annular coating head and insertable into the center hole of the annular coating head, and the annular coating head A method for producing an elastic roller, comprising the step of scraping the uncured rubber mixture in the vicinity of the annular slit with the disk by relatively moving it. The method for producing an elastic roller according to claim 1, wherein at least the following steps are repeated in order:
(1) Inserting the disk into the center hole of the annular coating head from the front in the moving direction of the annular coating head, and mounting the disk at a position forward in the moving direction from the opening of the annular slit;
(2) While discharging the uncured rubber mixture from the annular slit, the shaft core body and the annular slit are relatively moved so that the coating layer of the uncured rubber mixture is formed on the outer peripheral surface of the shaft core body. Forming step;
(3) A step of moving the disk rearward in the moving direction of the annular coating head to scrape off the uncured rubber mixture in the vicinity of the annular slit and taking it out from the rear in the moving direction of the annular coating head.   3. The method of manufacturing an elastic roller according to claim 1, wherein the disk is made of different materials on the inner peripheral side and the outer peripheral side, and the inner peripheral side material has a smaller bending strain than the outer peripheral side material.   The method for manufacturing an elastic roller according to any one of claims 1 to 3, wherein the disk has a bowl shape.

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