JP5486413B2 - Developer transport device, developing device, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image by an electrophotographic method, such as a printer, a facsimile machine, and a copying machine, as well as a developer conveying device and a developing device used in the image forming apparatus.

  In an image forming apparatus employing an electrophotographic method, the surface of the photoreceptor is uniformly charged by a charging device, and the surface of the photoreceptor is exposed by an exposure device (such as an LED head) to form an electrostatic latent image. The electrostatic latent image is developed by a developing device and transferred onto a medium by a transfer device to form an image.

  To the developing device, toner (developer) is supplied from a detachable toner cartridge through a toner supply port. The toner supplied into the developing device is supplied to the developing roller by a supply roller disposed below the toner supply port.

  Here, in the developing device, a developer transport member that transports and agitates the toner is provided in order to uniformly distribute the toner supplied from the toner supply port in the longitudinal direction of the supply roller. The developer conveying member is generally configured as a spiral member having a screw portion around the shaft (see, for example, Patent Document 1).

JP 2006-47470 A (see FIG. 5)

  However, since the screw (blade) of the spiral member has a cross-sectional shape that is thick at the base side, that is, the shaft side, and becomes narrower as it approaches the tip, when the toner is conveyed by rotating the spiral member, Along the surface of the screw may move in the direction opposite to the conveying direction, and may move toward the outside in the radial direction of the screw. For this reason, there is a problem that the efficiency of conveying and stirring the toner is low, the toner distribution is non-uniform, and the print quality is deteriorated such as blurring and uneven density.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to efficiently transport and stir the developer, thereby improving the print quality.

The developer transport device in the present invention includes a transport unit that transports the developer by rotating, and the transport unit includes a spiral member having a shaft portion and a screw portion provided around the shaft portion, A film extending in the axial direction of the shaft is provided on the outer periphery of the screw portion.

  According to the present invention, with the film provided on the outer periphery of the screw part, the developer can be kept within the rotation radius of the screw part, whereby the developer can be efficiently conveyed and stirred. As a result, it is possible to make the developer distribution uniform and improve the printing quality.

1 is a schematic diagram illustrating a basic configuration of an image forming apparatus according to a first embodiment of the present invention. It is sectional drawing which shows the developing device in the 1st Embodiment of this invention. It is a perspective view which shows the external appearance shape of a developing device. FIG. 2 is a cross-sectional view illustrating an internal configuration of the developing device according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a developer conveying member and a supply roller of the developing device according to the first embodiment of the present invention. FIG. 3 is a partial cross-sectional view of a developer transport member according to the first embodiment of the present invention. FIG. 6 is a schematic diagram for explaining a transport operation by a developer transport member in the first embodiment of the present invention. It is sectional drawing which shows the internal structure of the image development apparatus in the 2nd Embodiment of this invention. It is a perspective view which shows the developer conveyance member and supply roller of the developing device in the 2nd Embodiment of this invention. It is sectional drawing which shows the developing agent conveyance member and supply roller in the 2nd Embodiment of this invention. It is a fragmentary sectional view of the developer conveyance member in a 2nd embodiment of the present invention. FIG. 10 is a schematic diagram for explaining a transport operation by a developer transport member according to a second embodiment of the present invention.

First embodiment.
First, the basic configuration of the image forming apparatus according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic diagram showing a basic configuration of an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus according to the present embodiment employs a so-called color LED tandem system, and includes development devices 1K, 1Y, 1M, and 1C that form black, yellow, magenta, and cyan images in a housing 1a. ing. The developing devices 1K, 1Y, 1M, and 1C are arranged in a line from right to left here along the conveyance path of the recording medium P defined in the housing 1a. The developing devices 1K, 1Y, 1M, and 1C may be referred to as process units or image forming units.

  Exposure devices 2K, 2Y, 2M, and 2C are arranged above the photosensitive members 11 (described later) of the developing devices 1K, 1Y, 1M, and 1C. Each of the exposure apparatuses 2K, 2Y, 2M, and 2C (collectively referred to as exposure apparatus 2) is composed of an LED and is attached to the upper cover of the image forming apparatus. The upper cover is opened and closed when the developing devices 1K, 1Y, 1M, 1C in the housing 1a or a toner cartridge (developer container) (not shown) is attached or detached.

  The image forming apparatus further includes a paper feed cassette 5 that accommodates the recording medium P (paper), a paper feed mechanism 51 that feeds the recording medium P accommodated in the paper feed cassette 5 one by one to the conveyance path, and a developing device 1K. , 1Y, 1M, and 1C, a transfer device 4 that transfers the toner image formed on the recording medium P, and a fixing device 3 that fixes the toner image transferred onto the recording medium P to the recording medium 4.

  The paper feed cassette 5 accommodates the recording medium P and is detachably attached to the lower part of the housing 1a of the image forming apparatus. The paper feed mechanism 51 includes a paper feed roller that feeds the recording media P loaded in the paper feed cassette 5 one by one to the transport path. In addition, a registration roller that corrects the skew of the recording medium P and feeds it to the developing devices 1K, 1Y, 1M, and 1C may be provided.

  The transfer device 4 includes transfer rollers 41, 42, 43, 44 disposed opposite to the photoreceptors 11 of the developing devices 1 </ b> K, 1 </ b> Y, 1 </ b> M, 1 </ b> C, and drive rollers 45 disposed on both sides of these transfer rollers 41-44. And a tension roller 46 and a drive roller 45 and an endless belt 40 stretched around the tension roller 46. The endless belt 40 sucks and holds the recording medium P on the surface thereof, and moves by the rotational driving of the driving roller 45 to convey the recording medium P along the developing devices 1K, 1Y, 1M, and 1C. A bias voltage for transferring the toner image formed on each photoconductor 11 to the recording medium P is applied to the transfer rollers 41, 42, 43, 44.

  In addition, the fixing device 3 includes a heat roller 35 and a pressure roller 36, and heats and presses the recording medium P between the heat roller 35 and the pressure roller 36 to form a toner image on the recording medium P. To settle.

  FIG. 2 is a cross-sectional view showing the internal configuration of the developing devices 1K, 1Y, 1M, and 1C (collectively referred to as the developing device 1). The developing device 1 includes a photoconductor 11 as an electrostatic latent image carrier, a charging device 19 for uniformly charging the surface of the photoconductor 11, and a static electricity formed on the surface of the photoconductor 11 by the exposure device 2. A developing roller (developer carrying member) 12 for developing the electrostatic latent image, a supply roller 13 for supplying toner (developer) to the developing roller 12, and a toner storage chamber (for storing toner supplied to the supply roller 13) A developer storage chamber 22, a developing blade 15 that regulates the thickness of the toner layer on the developing roller 12, and a cleaning member that removes residual toner remaining on the surface of the photoreceptor 11. ) 18.

  Further, in the toner storage chamber 22, a first developer transport member 25 and a second developer transport member 26 are provided as a developer transport device for uniformizing the toner distribution in the toner storage chamber 22. Has been placed.

  The photoconductor 11 is a drum-like member composed of a conductive base material made of aluminum or the like and a surface layer made of an organic photoconductor, and rotates in a direction indicated by an arrow in the figure (counterclockwise in FIG. 2). The charging device 19 is a roller-like member in which a semiconductive elastic layer such as epichlorohydrin rubber is formed on the surface of a conductive metal shaft.

  The developing roller 12 is formed by forming a semiconductive elastic layer such as silicone rubber on the surface of a conductive metal shaft. The developing roller 12 is in contact with the surface of the photoconductor 11 and is arrowed in the drawing (clockwise in FIG. 2). Rotate to. The supply roller 13 is a conductive metal shaft provided with an elastic layer such as foam rubber, and contacts the surface of the developing roller 12 and rotates in the direction of the arrow in the figure (clockwise in FIG. 2).

  The developing blade 15 is formed by bending, for example, a metal plate-like member, and is pressed against the surface of the developing roller 12 with a constant pressing force at the bent portion. The developing blade 15 is fixed to a support member 16 provided in the developing device 1 with a screw.

  The cleaning member 18 is, for example, a rubber blade, and the tip is in contact with the surface of the photoconductor 11. The cleaning member 18 is also bonded to the bracket 24 by an adhesive method such as hot melt, and the bracket 24 is attached to the base frame 20 of the developing device 1. A waste toner transport member 23 made of a spiral or a coil spring for transporting the waste toner removed by the cleaning member 18 is disposed below the cleaning member 18.

  The photoconductor 11, the charging device 19, the developing roller 12, and the supply roller 13 are rotated in the above-described directions by a rotation driving unit (not shown). Further, a bias voltage is applied to the charging device 19, the developing roller 12, the supply roller 13, and the developing blade 15 by a power supply circuit (not shown). The surface of the photoreceptor 11 is charged by the charging device 19.

  FIG. 3 is a perspective view showing an external shape of the developing device 1. The developing device 1 has side frames 201 and 202 on both sides in the longitudinal direction, that is, on both sides in the axial direction of the photoconductor 11. The photoconductor 11, the charging roller 19, the developing roller 12, the supply roller 13, and the developer regulating member (the developing blade 15 and the supporting member 16) are supported by the side frames 201 and 202, and above the base frame 20. The cover frame 21 is attached.

  Among the above-described components of the developing device 1, the components contributing to the development of the electrostatic latent image on the photoconductor 11, that is, the developing roller 12, the supply roller 13, the developing blade 15, and the like constitute a “developing unit”. doing.

  The cover frame 21 of the developing device 1 has a cartridge mounting portion 203 for mounting a toner cartridge (not shown), and a toner supply port (developer supply port) for receiving toner supplied from the toner cartridge into the toner storage chamber 22. ) 17 is provided. The toner supply port 17 is disposed at the center in the longitudinal direction of the developing device 1. This is to improve the operability and prevent the user's hands from getting dirty by making it difficult for toner to leak or scatter when the toner cartridge is attached or detached. The toner replenishing port 17 is located above the first developer transport member 25 (FIG. 2).

  FIG. 4 is a cross-sectional view of the internal configuration of the developing device 1 as viewed from above. The first and second developer transport members 25 and 26 are spiral members having screw portions Sa, Sb, Sc, and Sd around shaft portions 250 and 260 (FIG. 5), respectively. Films 31a, 31b, 31c and 31d (collectively referred to as film 31) are provided at the tips (outer circumferences) of the screw portions Sa and Sb and the screw portions Sc and Sd of the first and second developer conveying members 25 and 26. Is wrapped and glued. The film 31 is made of a resin such as PET (polyethylene terephthalate) and has a thickness in the range of 0.1 mm to 0.2 mm.

  FIG. 5 is a perspective view showing the first and second developer conveying members 25 and 26 and the supply roller 13. As shown in FIG. 5, gears 25 g, 26 g, and 13 g are attached to the respective ends of the shaft portions 250 and 260 of the first and second developer conveying members 25 and 26 and the shaft portion of the supply roller 13. . The gears 25 g and 26 g of the first and second developer transport members 25 and 26 are connected to the gear 13 g of the supply roller 13 via idle gears 29, respectively. The first and second developer conveying members 25 and 26 rotate in the same direction as the rotation direction of the supply roller 13, respectively.

  Each of the first and second developer transport members 25 and 26 is integrally formed of ABS (acrylonitrile butadiene styrene) resin, PS (polystyrene) resin, or resin mixed with glass fiber. The first and second developer conveying members 25 and 26 have screw portions (blades) having the same height and the same pitch on shaft portions 250 and 260 serving as rotational axes, respectively. Here, for example, the outer diameter d of the shaft portions 250 and 260 is 6 mm, the pitch P of the screw portions is 15 mm, and the outer diameter D is 10 mm (FIG. 6).

  The first developer conveying member 25 includes screw portions Sa and Sb having different screw winding directions on both sides with respect to the central portion in the longitudinal direction. The first developer conveying member 25 also has flanges 251 and 252 at both ends of the screw. In the vicinity of the flanges 251 and 252, ribs 25a and 25b having the same height as the screw portions Sa and 2b are provided. have.

  The second developer conveying member 26 includes screw portions Sc and Sd whose winding directions are opposite to those of the screw portions Sa and Sb of the first developer conveying member 25. Further, a rib 26a having the same height as both the screw portions Sc and Sd is provided between the screw portions Sc and Sd. Note that the winding directions of the screw portions Sa and Sd are the same, and the winding directions of the screw portions Sb and Sc are the same.

  Films 31a, 31b, 31c, and 31d are wound around the tips (outer circumferences) of the screw portions Sa, Sb, Sc, and Sd, and are fixed by an adhesive. FIG. 6 is an enlarged partial cross-sectional view showing a part of the first developer conveying member 26 as an example. The film 31a is spirally wound along the screw portion Sa and bonded to the tip surface (outer peripheral surface) of the screw portion Sa.

  Films 31a, 31b, 31c, 31d (collectively referred to as film 31) are arranged such that when toner is conveyed by rotation of the first and second developer conveying members 25, 26, the toner is supplied to the screw portions Sa, Sb, A substantially cylindrical wall is formed which is held inside the rotation radius of Sc and Sd. The width W of the films 31a, 31b, 31c, 31d is 1/2 or less than 1/2 the pitch P of the screw portions Sa, Sb, Sc, Sd. The first and second developer transport members 25 and 26 are supported by holding members 27R and 27L (FIG. 4) disposed on both sides in the longitudinal direction. Seal sponges 28R and 28L (FIG. 4) for preventing toner leakage are provided inside the holding members 27R and 27L (on the toner storage chamber 22 side).

Next, the operation of the image forming apparatus configured as described above will be described.
In each developing device 1, the photoconductor 11, the developing roller 12, and the supply roller 13 are rotated by a driving motor (not shown). A bias voltage is applied to the charging device 19, the developing roller 12, the supply roller 13, and the developing blade 15 by a power supply circuit (not shown). The toner in the toner storage chamber 22 is supplied to the developing roller 12 by the supply roller 13. The toner supplied to the developing roller 12 passes through the pressure contact portion between the developing roller 12 and the developing blade 15 by the rotation of the developing roller 12, and a toner layer having a uniform thickness that is frictionally charged is formed.

  On the other hand, the surface of the photoreceptor 11 is uniformly charged by the transfer device 11, and an electrostatic latent image corresponding to the image data is formed by light irradiation of the exposure device 2. The electrostatic latent image is developed (visualized) when toner on the surface of the developing roller 12 adheres to become a toner image.

  On the other hand, from the paper feed cassette 5 of the image forming apparatus, the recording medium P is sent to the transport path one by one by the paper feed mechanism 51 and sent to the developing devices 1K, 1Y, 1M, 1C and the transfer device 4. Further, the recording medium P is sucked and held by the transport belt 40 and is transported so as to pass through the developing devices 1K, 1Y, 1M, and 1C.

  When the recording medium P passes through the developing devices 1K, 1Y, 1M, and 1C, the toner image formed on the surface of each photoreceptor 11 as described above is transferred to the recording medium P by the transfer rollers 41, 42, 43, and 44. Are sequentially transferred.

  The recording medium P to which the toner has been transferred is sent to the fixing device 3 and heated and pressed by the heat roller 35 and the pressure roller 36, and the toner image is fixed on the recording medium P. The toner image on which the recording medium P is fixed is discharged by a discharge roller (not shown) and is stacked on a discharge stacker 52 provided on the upper part of the image forming apparatus.

Next, the operation of the first and second developer transport members 25 and 26 will be described.
Since the toner replenishing port 17 is disposed at the center in the longitudinal direction of the developing device 1 (see FIG. 4), the toner supplied from the toner replenishing port 17 into the toner storage chamber 22 is the center in the toner storage chamber 22. It is easy to collect a lot in the part. Therefore, in order to make the toner distribution in the toner storage chamber 22 uniform in the longitudinal direction, first and second developer conveying members 25 and 26 are arranged. As described above, in the first and second developer agitating devices 25 and 26, the rotation of the supply roller 13 is transmitted via the idle gear 29 and rotates in the same direction as the supply roller 13.

  Due to the rotation of the first developer conveying member 25, the toner in the toner storage chamber 22 is conveyed from the central portion in the longitudinal direction toward both ends (in the directions of arrows M and N shown in FIG. 4). Further, the ribs 25a and 25b (FIG. 5) at both ends of the first developer conveying member 25 cause the toner to move toward the second developer conveying member 26 (in the direction of arrow 0 and arrow P shown in FIG. 4). Sent out.

  In addition, the toner in the toner storage chamber 22 is conveyed from both ends in the longitudinal direction toward the center by the rotation of the second developer conveying member 26 (in the directions of arrows Q and R shown in FIG. 4). . Further, the toner is sent out toward the first developer conveying member 25 (in the direction of arrow S and arrow T shown in FIG. 4) by the rib 26a at the center of the second developer conveying member 26.

  As described above, the first and second developer transport members 25 and 26 form circulation paths on both sides (left side and right side) with respect to the longitudinal center in the toner storage chamber 22 to transport the toner, Stirring.

  FIGS. 7A and 7B are schematic diagrams for explaining the toner conveying operation by the first developer conveying members 25 and 26 and the films 31a to 31d. Here, for convenience of description, the screw portions Sa to Sd are referred to as “screw portion S”, and the films 31 a to 31 d are referred to as “film 31”.

  FIG. 7A shows a toner conveying operation by the first and second developer conveying members 25 and 26 when the film 31 of the present embodiment is not provided. The first and second developer transport members 25 and 26 are molded of resin, and due to their mold structure, the cross section of the screw portion S is thick at the root portion (shaft portions 250 and 260 side), and the tip portion becomes thinner. ing. Therefore, when the first and second developer conveying members 25 and 26 are rotated, toner existing between the screw portions S (between adjacent blades) is indicated by an arrow T in FIG. In addition, the toner may move along the surface of the screw portion S in the direction opposite to the conveyance direction or move outward in the radial direction, and the toner conveyance efficiency is low. Therefore, it is difficult to sufficiently uniformize the toner distribution in the longitudinal direction in the toner storage chamber 22.

  On the other hand, a pipe-shaped partition for guiding the toner in the axial direction may be disposed around the first and second developer conveying members 25 and 26. However, in such a configuration, it is necessary to provide a mechanism for further transporting the toner supplied from the toner supply port 17 to the toner storage chamber 22 to the inside of the pipe-shaped partition wall, and the configuration of the developing device 1 is complicated. Become.

  Therefore, in the present embodiment, as shown in FIG. 7B, a film 31 is wound around and fixed to the tips of the screw portions S of the first and second developer transport members 25 and 26. When the first and second developer conveying members 25 and 26 are rotated, the toner moves along the surface of the screw portion S, but the film 31 is formed so as to form a wall at the tip (outer periphery) of the screw portion S. Therefore, the toner is reliably conveyed in the axial direction of the first and second developer conveying members 25 and 26 without moving the toner in the direction opposite to the conveying direction or moving radially outward. can do.

  Further, since the film 31 has a width W (FIG. 6) that is ½ or less of the pitch P of the screw portion S and extends spirally along the screw portion S, the toner in the toner storage chamber 22 is removed. It does not prevent reaching between the screw parts S (between the blades).

  Thus, by providing the films 31a, 31b, 31c, 31d at the tips of the screw portions Sa, Sb, Sc, Sd of the first and second developer transport members 25, 26, the first and second developments are performed. The toner conveying efficiency by the agent conveying members 25 and 26 can be improved, and the toner in the toner storage chamber 22 can be made uniform in the longitudinal direction.

  As described above, according to the present embodiment, the toner transport efficiency is improved by the rotation of the developer transport members 25 and 26, and the toner distribution in the toner storage chamber 22 is made uniform in the longitudinal direction. , Blurring and density unevenness are eliminated, and print quality can be improved.

Second embodiment.
FIG. 8 is a cross-sectional view of the internal configuration of the developing device 1 according to the second embodiment as viewed from above. FIG. 9 is a perspective view showing the first and second developer conveying members 25 and 26 and the supply roller 13 in the second embodiment.

  The second embodiment is different from the first embodiment in the configuration of the film bonded to the first and second developer conveying members 25 and 26, and the other configurations are the same as those in the first embodiment. It is the same as the form. Here, differences from the first embodiment will be described.

  In the first embodiment described above, the films 31a to 31d are spirally wound and bonded along the tips of the screws of the first and second developer conveying members 25 and 26. In the second embodiment, as shown in FIGS. 8 and 9, a film 32 is bonded in the longitudinal direction of the first and second developer conveying members 25 and 26.

  FIG. 10 is a cross-sectional view orthogonal to the axial direction of the first and second developer conveying members 25 and 26 and the supply roller 13. This cross section corresponds to a cross section in a plane passing through the screw portions Sa and Sd of the first and second developer transport members 25 and 26. FIG. 11 is an enlarged partial cross-sectional view showing a part of the first developer conveying member 25 as an example. As shown in FIG. 10, in the cross section orthogonal to the axial direction of the first developer conveying device 25, the outer periphery of the screw portion Sa is equally divided into eight sections, and the films 32a1, 32a2, 32a3, and 32a4 are divided every other section. It is glued. Similar films 32b1, 32b2, 32b3, 32b4 (not shown in FIG. 10) are also provided in the other screw portion Sb of the first developer conveying device 25.

  Similarly, in the cross section orthogonal to the axial direction of the second developer conveying device 26, the tip (outer periphery) of the screw portion Sc is equally divided into eight sections, and the film members 32c1, 32c2, 32c3, and 32c4 are divided every other section. It is glued. Similar films 32d1, 32d2, 32d3, 32d4 (not shown in FIG. 10) are also provided in the other screw portion Sd of the second developer conveying device 25. The films 32a1 to 32a4, 32b1 to 32b4, 32c1 to 32c4, and 32d1 to 32d4 are collectively referred to as a film 32.

  Similar to the first embodiment, the film 32 is made of a resin such as PET and has a thickness of 0.1 mm to 0.2 mm.

  The image forming operation in the second embodiment is the same as that in the first embodiment. In the toner storage chamber 22, two toner circulation paths are configured to stir and transport the toner, except for the operations of the first and second developer transport members 25 and 26. It is the same as the form.

  FIG. 12 is a schematic diagram for explaining the toner transport operation by the first and second developer transport members 25 and 26. When the first and second developer transport members 25 and 26 rotate, the toner moves along the surface of the screw portion S. A film 32 is attached to the tip of the screw portion S so as to form a wall. Therefore, the toner is reliably conveyed in the axial direction of the first and second developer conveying members 25 and 26 without moving the toner in the direction opposite to the conveying direction or moving radially outward. Can do.

  Further, since the films 32 are arranged at regular intervals in the circumferential direction of the screw portion S (see FIG. 10), the toner in the toner storage chamber 22 is between the screw portions S (between the blades). Will not interfere with reaching.

  As described above, according to the present embodiment, the developer transport efficiency is improved by the rotation of the first and second developer transport members 25 and 26, and the toner distribution in the toner storage chamber is in the longitudinal direction. Since it is made uniform, blurring and density unevenness are eliminated, and it is possible to obtain the effect of improving the printing quality.

  In the first and second embodiments described above, the films 31 and 32 are bonded to the tip (outer periphery) of each screw, but may be fixed by a method other than bonding. The material of the films 31 and 32 is most preferably PET, but may be other materials (preferably resin).

  In the first and second embodiments described above, the first and second developer conveying members 25 and 26 are described as the developer conveying devices. However, the present invention has such a configuration. It is not limited. For example, it may have only one developer conveying member, or may have three or more. The direction of the screw of each developer conveying member can also be appropriately changed according to the purpose of use.

  The developer conveying device described in each of the above embodiments is applied to an image forming apparatus such as a copying machine, a printer, and a facsimile machine that includes a developing device that develops an electrostatic latent image formed on an image carrier. Can do.

  1, 1K, 1Y, 1M, 1C developing device, 2, 2K, 2Y, 2M, 2C exposure device, 3 fixing device, 4 transfer device, 5 paper feed cassette, 11 photoconductor, 12 developing roller, 13 supply roller, 13g Gear, 15 developing blade, 17 toner supply port, 18 cleaning member, 19 fixing device, 22 toner storage chamber, 23 waste toner conveying member, 25 first developer conveying member, 25a, 25b rib, 25g gear, 26 second Developer transport member, 26a rib, 26g gear, 27R, 27L holding member, 28R, 28L seal member, 29 idle gear, 31, 31a-31d film, 32, 32a1-32a4, 32b1-32b4, 32c1-32c4, 32d1 ~ 32d4 film, 250,260 Café part.

Claims (10)

A transport unit that transports the developer by rotating,
The transport unit is
A spiral member having a shaft portion and a screw portion provided around the shaft portion;
A developer conveying device comprising a film extending in an axial direction of the shaft on an outer periphery of the screw portion.   The developer conveying device according to claim 1, wherein the film is provided in a spiral shape along the outer periphery of the screw portion.   The developer conveying device according to claim 2, wherein a width of the film is ½ or less of a pitch of the screw part. In a plane perpendicular to the axial direction of the shaft portion, according to claim 1 in which a plurality of said film, characterized in that provided at equal intervals in a circumferential direction around the axial center of the shaft portion Developer transport device. The spiral member, the developer conveying device according to any one of claims 1, characterized in that it is formed of resin to 4. The film, on the outer periphery of the screw portion, the developer conveying device according to any one of claims 1, characterized in that it is fixed by bonding to 5. The spiral member has two sections in its axial direction,
In each segment, the winding direction of the screw portion, the developer conveying device according to any one of claims 1, wherein up to 6 to be opposite to each other. The transport unit, the developer conveying device according to any one of claims 1, characterized in that a pair of said spiral member in parallel to each other up to 7. A developing device having a developer conveying apparatus according to any one of claims 1 to 8. An image forming apparatus having a developer conveying apparatus according to any one of claims 1 to 8.

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