JP5678001B2 - Toner conveying apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a toner conveying device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine thereof.

  In a conventional image forming apparatus, a powder developer is mainly used, and an electrostatic latent image formed on an image carrier such as a photosensitive drum is visualized by using the developing apparatus, and the visible image (toner) In general, a process of fixing an image) onto a recording medium and then performing a fixing process. The toner remaining on the surface of the image carrier is removed by a cleaning device, and a new toner image is formed. The residual toner removed by the cleaning device is stored in a waste toner bottle. When the waste toner bottle becomes full after printing a predetermined number of sheets, the user is notified and the waste toner bottle is discarded or replaced.

  As a waste toner collecting path from the cleaning device to the waste toner bottle, a toner transport path having a transport screw in a pipe-shaped transport path is known. In such a toner conveyance path, when the outer peripheral track during rotation of the conveyance screw becomes larger than the inner diameter of the conveyance path due to dimensional tolerance of the outer diameter of the conveyance screw and the inner diameter of the conveyance path, warpage of the conveyance screw, or the like, There is a possibility that an excessive rotational load is generated due to friction and the conveying screw does not rotate. Therefore, the dimensions are usually set so that the outer diameter of the conveying screw is smaller than the inner diameter of the conveying path.

  However, when such a dimension setting is performed, there is a clearance (gap) between the conveying screw and the conveying path, so that if the conveying screw is warped, the conveying screw is swung in the radial direction (eccentric. Rotating, hitting the inner surface of the transport path and hitting sound.

  More specifically, when the conveying screw is warped, when the warping is downward, the bending due to the weight of the conveying screw is added in the same direction as the warping, and the amount of deformation increases. On the other hand, when the warp is upward, the deformation due to the weight of the conveying screw acts in the opposite direction to the warp. For this reason, when the conveying screw rotates from a state in which the warping is upward, since the deformation due to the weight of the conveying screw gradually acts in the direction of increasing the warping from the state where the deformation amount is small and balanced, the conveying screw becomes large. It rotates while deforming so as to wave, and collides with the inner surface of the conveyance path. At this time, the generated striking sound increases as the warp increases, and the clearance (gap) between the conveying screw and the inner surface of the conveying path increases, and increases as the weight of the conveying screw increases.

  Therefore, Patent Document 1 provides a portion in which the outer diameter of the spiral protrusion (spiral wing) of the conveying screw is very close to the inner diameter of the cylindrical conveying path, and a part of the outer diameter of the conveying screw is cylindrically conveyed. A toner conveying device is disclosed that is capable of stably rotating while being in contact with the inside of a path.

  Patent Document 2 includes a pipe body having a semi-tubular portion and a semi-tubular lid joined to the semi-tubular portion. The joining surface of the pipe body and the semi-tubular lid is substantially flat, and is joined. A toner conveying pipe excellent in airtightness and dimensional accuracy with ultrasonic welding of the part is disclosed.

JP 2002-132109 A JP 2005-91809 A

  However, in the methods of Patent Documents 1 and 2, there is a limit in setting the clearance between the conveying screw and the cylindrical conveying path due to dimensional tolerances and assembly tolerances of the parts, and if the warp generated in the conveying screw exceeds the clearance, the conveying path The impact sound could not be prevented reliably. Moreover, in the structure of patent document 1, since the part in which the outer diameter of the spiral wing | blade and the internal diameter of the cylindrical conveyance path were close is formed over the perimeter in one place of the axial direction of a cylindrical conveyance path, it is cylindrical. Toner clogging in the conveyance path is likely to occur, and the rotation load of the conveyance screw also increases. As a result, the fluidity of the toner is lowered due to frictional heat and the conveyance efficiency is deteriorated. If the toner is left as it is for a long time, the toner may be solidified.

  In the above, a problem has been described in the case where the toner conveying path having the conveying screw in the pipe-shaped conveying path is used as the waste toner collecting path from the cleaning device to the waste toner bottle. However, in order to supply toner to the developing device. In the toner replenishment path used when replenishing toner from the toner cartridge to the developing device according to the consumption of toner in the developing device, a toner conveying path having a conveying screw in the conveying pipe is also provided. Similar problems arise when used.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention includes a toner conveying device that can prevent the generation of a striking sound due to a collision between the conveying screw and the inner surface of the conveying path and can maintain stable toner conveying performance over a long period of time. An object is to provide an image forming apparatus.

  In order to achieve the above object, the present invention has a circular cross section in which a conveying screw having a rotating shaft and a conveying blade formed on the outer peripheral surface of the rotating shaft, and the conveying screw is rotatably arranged inside. In the toner transport device comprising a toner transport pipe, the toner transport pipe includes a first pipe member that forms a half of the outer peripheral surface viewed from the axial direction and a second pipe member that forms the remaining half of the outer peripheral surface. The inner wall surface of the first pipe member and the second pipe member formed in combination has a semicircular arc-shaped cross section having an inner peripheral surface concentric with the inner wall surface around the central axis of the toner conveying pipe. Are formed at positions that do not overlap each other in the axial direction of the toner transport pipe, and the distance from the central axis to the inner peripheral surface is equal to the radius of the transport blade or the radius of the transport blade Remote it is characterized by slightly larger.

  Further, the present invention provides the toner conveying device having the above-described configuration, wherein the first pipe member and the second pipe member are an upper pipe member and a lower pipe member that constitute an upper half and a lower half of the toner conveying pipe, respectively. The convex portion includes a first rib formed at at least one location on the inner wall surface of the upper pipe member and a second rib formed at a plurality of locations on the inner wall surface of the lower pipe member.

  According to the present invention, in the toner conveying device having the above-described configuration, the second ribs are formed at intervals other than one pitch of the conveying wings.

  According to the present invention, in the toner conveying device having the above-described configuration, the convex portion fixes an elastic member to at least one place on the inner wall surface of the first pipe member and at least one place on the inner wall surface of the second pipe member. It is characterized by being formed.

  According to the present invention, in the toner transport device having the above-described configuration, each of the elastic members is fixed in a range of ½ or more of the pitch of the transport wings.

  According to the present invention, in the toner transport device having the above-described configuration, a material having a lower friction coefficient than that of the elastic member is laminated on the inner peripheral surface of the elastic member.

  According to the present invention, in the toner conveying device having the above-described configuration, the convex portion is formed so as to face a range within 1/3 of the entire length of the conveying screw at a substantially central portion in the longitudinal direction of the conveying screw.

  The present invention also provides an image forming apparatus on which the toner conveying device having the above-described configuration is mounted.

  According to the first configuration of the present invention, the conveying screw is supported by the convex portion having a semicircular cross section formed on the inner wall surface of the first pipe member and the second pipe member so that the rotation axis is substantially straight. Therefore, the deformation of the conveying screw due to the interaction between the warp of the conveying screw and the bending due to its own weight is suppressed. Therefore, it is possible to effectively suppress the generation of a striking sound due to a collision between the conveying screw and the inner surface of the toner conveying pipe. Further, since each convex portion is formed at a position that does not overlap with each other in the axial direction of the toner transport pipe, it is possible to suppress toner clogging in the toner transport pipe and an increase in the rotational load of the transport screw.

  Further, according to the second configuration of the present invention, in the toner conveyance device of the first configuration, the first pipe member and the second pipe member are the upper pipes constituting the upper half and the lower half of the toner conveyance pipe, respectively. And a lower pipe member, the first rib formed at at least one location on the inner wall surface of the upper pipe member and the second rib formed at a plurality of locations on the inner wall surface of the lower pipe member. Thereby, it rotates in the state supported by the 1st rib and the 2nd rib so that the axis of rotation of a conveyance screw may become a straight line. Further, the first rib and the second rib can be integrally formed with the upper pipe member and the lower pipe member. Furthermore, the lower part of a conveyance screw can be stably supported by forming a 2nd rib in several places of a lower pipe member.

  Further, according to the third configuration of the present invention, in the toner conveyance device of the second configuration, the second ribs are formed at intervals other than one pitch of the conveyance wings, so that the conveyance wings by the rotation of the conveyance screw can be obtained. Regardless of the change in the phase, a part of the outer peripheral edge of the conveying wing is always in contact with one of the second ribs, so that the lower part of the conveying screw is reliably supported by the second rib.

  According to the fourth configuration of the present invention, in the toner transport device of the first configuration, at least one location on the inner wall surface of the first pipe member and at least one location on the inner wall surface of the second pipe member, By fixing the elastic member and forming the convex portion, the elastic member rotates while being supported by the elastic member so that the rotation shaft of the conveying screw is substantially in a straight line. In addition, due to the silencing effect of the elastic member, it is possible to effectively suppress the occurrence of a striking sound due to a collision between the conveying screw and the inner surface of the toner conveying pipe.

  Further, according to the fifth configuration of the present invention, in the toner conveyance device of the fourth configuration, each elastic member is fixed in a range of 1/2 or more of the pitch of the conveyance blades, thereby rotating the conveyance screw. Regardless of the change in the phase of the conveying wing due to the above, a part of the outer peripheral edge of the conveying wing is always in contact with the elastic member. Therefore, it is possible to effectively reduce the collision noise between the inner wall surface of the toner conveying pipe and the conveying screw. Further, the lower part of the conveying screw is reliably supported by the elastic member.

  According to the sixth configuration of the present invention, in the toner conveying device having the fourth or fifth configuration, a material having a lower friction coefficient than that of the elastic member is laminated on the inner peripheral surface of the elastic member. The sliding load between the conveying wing and the elastic member is reduced, and an increase in the rotational load of the conveying screw can be suppressed.

  Further, according to the seventh configuration of the present invention, in the toner conveyance device having any one of the first to sixth configurations, the conveyance screw is conveyed at a substantially central portion in the longitudinal direction of the conveyance screw that is likely to be warped. By forming the convex portion so as to face the range within 1/3 of the total length of the screw, the convex portion can be formed in the minimum necessary range where the effect of smoothly rotating the conveying screw can be obtained.

  Further, according to the eighth configuration of the present invention, the mounting of the toner conveying device having any one of the first to seventh configurations makes it possible to generate a striking sound due to a collision between the conveying screw and the inner surface of the toner conveying pipe. In addition, the image forming apparatus can be effectively prevented from lowering and solidifying the fluidity of the toner in the toner conveying pipe and excellent in quietness and maintenance.

1 is a schematic cross-sectional view showing an overall configuration of an image forming apparatus 1 including a toner conveying device 30 of the present invention. Side surface sectional drawing which shows the structure of the toner conveying apparatus 30 which concerns on one Embodiment of this invention, and the cleaning apparatus 7 vicinity connected with this. 1 is a perspective view showing a state where a toner transport pipe 31 constituting a toner transport device 30 according to a first embodiment of the present invention is cut at a substantially central portion in a longitudinal direction. FIG. 3 is an enlarged perspective view near the cross section of the toner transport pipe 31 in FIG. 3. 1 is a perspective view showing a state where an upper pipe member 31a of a toner transport pipe 31 used in the toner transport device 30 of the first embodiment is removed. 1 is a partial sectional view in which a toner transport pipe 31 used in the toner transport device 30 of the first embodiment is divided into two vertically along a longitudinal direction. The perspective view which shows the state which removed the upper pipe member 31a of the toner conveyance pipe 31 used for the toner conveying apparatus 30 which concerns on 2nd Embodiment of this invention. A partial cross-sectional view in which a toner transport pipe 31 used in the toner transport device 30 of the second embodiment is vertically divided into two along the longitudinal direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus 1 of the present invention. In an image forming apparatus (for example, a monochrome printer) 1, when performing an image forming operation, the photosensitive drum 3 that rotates clockwise in FIG. 1 is uniformly charged by the charging unit 2, and an exposure unit (laser) based on the image data. An electrostatic latent image is formed on the photosensitive drum 3 by a laser beam from the scanning unit 4), and a developer (hereinafter referred to as toner) is attached to the electrostatic latent image by the developing unit 5 to form a toner image. The

  The toner is supplied to the developing unit 5 from the toner container 6. The image data is transmitted from a personal computer (not shown) or the like. Further, a static elimination device (not shown) for removing residual charges on the surface of the photosensitive drum 3 is provided on the downstream side of the cleaning device 7 with respect to the rotation direction of the photosensitive drum 3.

  A sheet (transfer paper, OHP, or the like) is conveyed from the sheet feeding cassette 8 via the sheet conveyance path 9 toward the photosensitive drum 3 on which the toner image is formed as described above, and is transferred by the registration roller pair 10. 11 (image transfer unit) is adjusted for feeding timing. Then, the toner image formed on the surface of the photosensitive drum 3 is transferred to the sheet by the transfer roller 11. The sheet onto which the toner image has been transferred is separated from the photosensitive drum 3 and conveyed to a fixing unit 13 having a fixing roller pair 12 to fix the toner image. The sheet that has passed through the fixing unit 13 is conveyed to the upper part of the apparatus by the sheet conveying path 14 and is discharged from the discharge roller pair 15 to the discharge tray 16.

  On the other hand, the toner remaining on the surface of the photosensitive drum 3 is removed by the cleaning device 7. Then, after the residual charge is removed from the photosensitive drum 3 by a charge removal device (not shown), it is charged again by the charging unit 2, and image formation is performed in the same manner.

  The photosensitive drum 3 is formed by laminating a photosensitive layer made of amorphous silicon (a-Si) or an organic photosensitive layer (OPC) on an outer peripheral surface of an aluminum drum, for example, so that the surface is charged by the charging unit 2. It has become. Then, an electrostatic latent image in which charging is attenuated is formed on the surface that has received the laser beam from the exposure unit 4. The charging unit 2 charges the surface of the photosensitive drum 3 by discharging (for example, corona discharge). For example, the charging unit 2 is discharged by applying a high voltage using a thin wire or the like as an electrode. .

  The exposure unit 4 irradiates the photosensitive drum 3 with a light beam (for example, a laser beam) based on the image data, and forms an electrostatic latent image on the surface of the photosensitive drum 3. The developing unit 5 includes a developing roller disposed so as to face the photosensitive drum 3, and a developer contained therein is attached to the electrostatic latent image on the photosensitive drum 3 by the developing roller to form a toner image.

  The cleaning device 7 removes the toner (residual toner) remaining on the surface of the photosensitive drum 3 after the toner image is transferred to the sheet. The detailed configuration of the cleaning device 7 will be described later.

  In the fixing unit 13, a fixing roller pair 12 including a heating roller rotating in a clockwise direction in FIG. 1 and a pressure roller rotating in a counterclockwise direction in FIG. ing. The sheet on which the toner image is transferred by the transfer roller 11 is carried into the fixing unit 13 and passes through the fixing nip portion of the fixing roller pair 12. At this time, the toner image on the sheet is melted and fixed to be a permanent image by being heated and pressurized at a predetermined temperature and pressure.

  FIG. 2 is a cross-sectional view of a principal part showing a configuration in the vicinity of the cleaning device 7 including the toner conveying device 30 of the present invention. The housing 7 a of the cleaning device 7 includes a rubbing roller 21, a cleaning blade 22, and a recovery screw 23 that are in line contact with the longitudinal direction of the photosensitive drum 3 by a spring (not shown).

  The rubbing roller 21 is pressed against the photosensitive drum 3 with a predetermined pressure, and is rotated (forward rotation) in the same direction on the contact surface with the photosensitive drum 3 by a driving means (not shown). It is controlled to be faster than the peripheral speed of the body drum 3 (1.2 times here). Examples of the rubbing roller 21 include a structure in which a foam layer made of EPDM rubber and having an Asuka C hardness of 55 ° is formed as a roller body around a metal shaft. The material of the roller body is not limited to EPDM rubber, but may be a rubber or foamed rubber body of another material, and those having an Asuka C hardness of 10 to 90 ° are preferably used.

  A cleaning blade 22 is fixed in contact with the photosensitive drum 3 on the surface of the photosensitive drum 3 downstream of the contact surface with the rubbing roller 21 in the rotation direction. As the cleaning blade 22, for example, a polyurethane rubber blade having a JIS hardness of 78 ° is used, and is attached at a predetermined angle with respect to the tangential direction of the photosensitive drum 3 at the contact point. The material, hardness, dimensions, the amount of biting into the photosensitive drum 3 and the pressure contact force of the cleaning blade 22 are appropriately set according to the specifications of the photosensitive drum 3.

  The residual toner scraped off from the surface of the photosensitive drum 3 by the rubbing roller 21 or the cleaning blade 22 falls due to gravity and gradually accumulates in the housing 7a. Then, as the recovery screw 23 rotates, the toner in the housing 7a is sequentially conveyed in the longitudinal direction of the housing 7a (direction perpendicular to the paper surface of FIG. 2), and a toner discharge portion provided at one end of the bottom surface of the housing 7a. 25 is discharged to the outside of the cleaning device 7.

  The toner conveying device 30 includes a toner conveying pipe 31 and a conveying screw 35. A toner carry-in port 32 and a toner discharge port 33 are formed at both ends of the toner transport pipe 31. The toner carry-in port 32 is connected to the toner discharge unit 25 of the cleaning device 7, and the toner discharge port 33 is connected to a waste toner bottle 37. Has been. The conveying screw 35 includes a conveying blade (spiral blade) 35a and a rotating shaft 35b penetrating through the center thereof, and is rotatably supported in the toner conveying pipe 31. One end of the rotating shaft 35b extends to the outside of the toner conveying pipe 31, and a drive input gear 39 is attached to the tip of the rotating shaft 35b. The drive input gear 39 is connected to a drive motor (not shown), and the conveying screw 35 is rotationally driven at a predetermined speed. As the conveying screw 35 rotates in the direction of arrow A in the drawing, the toner carried into the toner conveying pipe 31 from the cleaning device 7 via the toner inlet 32 is sequentially conveyed in the toner conveying pipe 31 in the direction of arrow B. The toner is stored in the waste toner bottle 37 through the toner discharge port 33.

  3 is a perspective view showing a state in which the toner transport pipe 31 used in the toner transport device 30 according to the first embodiment of the present invention is cut at a substantially central portion in the longitudinal direction, and FIG. 4 is a cross-sectional view of the toner transport pipe 31. FIG. 5 is a perspective view showing a state in which the upper pipe member 31a of the toner transport pipe 31 used in the toner transport device 30 of the first embodiment is removed. 6 is a partial cross-sectional view in which the toner transport pipe 31 used in the toner transport device 30 of the first embodiment is vertically divided into two along the longitudinal direction. The toner conveying pipe 31 is formed in a cylindrical shape by combining an upper pipe member 31a and a lower pipe member 31b having a semicircular cross section.

  A first rib 40a and a second rib 40b are integrally formed on the inner wall surfaces of the upper pipe member 31a and the lower pipe member 31b, respectively. The first rib 40a and the second rib 40b have a semicircular cross section in a direction orthogonal to the axial direction of the toner transport pipe 31, and when viewed from the axial direction of the toner transport pipe 31, the first rib 40a and the second rib 40b. The inner peripheral surface of the rib 40b is concentric with the central axis O of the toner transport pipe 31 as the center, and the distance from the central axis O to the inner peripheral surface is equal to the radius of the transport blade 35a of the transport screw 35 or the transport It is formed slightly larger than the radius of the wing 35a.

  When the pitch of the conveying blades 35a of the conveying screw 35 is L, two second ribs 40b are formed at a pitch of L / 2, and the first ribs 40a are arranged in the axial direction between the second ribs 40b. One is formed at a shifted position. The conveying screw 35 is supported by the first rib 40a and the second rib 40b at the outer peripheral edge of the conveying blade 35a at a substantially central portion in the longitudinal direction. At this time, the axis center of the rotation shaft 35 b of the conveying screw 35 substantially coincides with the central axis O of the toner conveying pipe 31.

  With this configuration, when the conveying screw 35 is warped, the direction of the warping exceeds the uppermost point with the rotation of the conveying screw 35, and even if an attempt is made to swing in the direction in which the warping is increased by the deflection of its own weight (radially outward), Since the outer peripheral edge of the conveying blade 35a is in contact with the first rib 40a and the second rib 40b formed on the inner wall surface in the rotational direction, the conveying screw 35 undulates in the radial direction due to the interaction between the warp and the deflection due to its own weight. Deformation is suppressed. Accordingly, the conveying screw 35 rotates with the first rib 40a and the second rib 40b being supported so that the rotation shaft 35b is substantially in a straight line, and is hit by collision between the conveying screw 35 and the inner surface of the toner conveying pipe 31. Generation of sound can also be effectively suppressed.

  Here, since the 2nd rib 40b is formed in the space | interval of 1/2 (L / 2) of the pitch L of the conveyance blade 35a, irrespective of the change of the phase of the conveyance blade 35a accompanying rotation of the conveyance screw 35. A part of the outer peripheral edge of the conveying blade 35a is always in contact with one of the second ribs 40b. Thereby, the lower part of the conveyance screw 35 is reliably supported by the 2nd rib 40b. In addition, the space | interval of the 2nd rib 40b is not restricted to L / 2, For example, L / 3 and 3L / 2 may be sufficient. That is, as long as the conveying blades 35a are formed at intervals other than one pitch, a part of the outer peripheral edge of the conveying blades 35a is always in contact with one of the second ribs 40b.

  Further, since the first rib 40 a is formed at a position shifted from the second rib 40 b (does not overlap the second rib 40 b) in the longitudinal direction (axial direction) of the toner transport pipe 31, A gap that is continuous in the longitudinal direction of the conveying screw 35 exists between the wall surface and the conveying blade 35a. Therefore, the toner carried into the toner transport pipe 31 can move through this gap, and is not blocked by the first rib 40a and the second rib 40b.

  Therefore, it is possible to prevent toner clogging in the toner conveyance pipe 31 and the increase in the rotational torque of the conveyance screw 35 accompanying this. Further, since the rotation of the conveying screw 35 smoothly rotates without increasing, the generation of frictional heat due to the rotation of the conveying screw 35 can be suppressed, and the fluidity of the toner in the toner conveying pipe 31 is reduced. And solidification can be effectively suppressed. Furthermore, the load of the drive motor that rotates the conveying screw 35 can also be reduced.

  In the present embodiment, the first rib 40 a and the second rib 40 b are formed only in the substantially central portion in the longitudinal direction of the toner transport pipe 31. However, the first rib 40 a and the second rib 40 b are formed in the longitudinal direction of the toner transport pipe 31. It may be formed at a plurality of locations at predetermined intervals over the entire area. However, in most cases, the warp of the conveying screw 35 occurs in the central portion in the longitudinal direction, and the effect of supporting the conveying screw 35 even if the first rib 40a and the second rib 40b are formed near both ends in the longitudinal direction. Can not expect much. A sufficient effect can be expected if the first rib 40a and the second rib 40b are formed so as to face a range within 1/3 of the entire length of the conveying screw 35 at a substantially central portion in the longitudinal direction of the conveying screw 35.

  FIG. 7 is a perspective view showing a state in which the upper pipe member 31a of the toner conveyance pipe 31 used in the toner conveyance device 30 according to the second embodiment of the present invention is removed, and FIG. 8 is a toner conveyance device according to the second embodiment. 3 is a partial cross-sectional view in which a toner transport pipe 31 used for the belt 30 is divided into two vertically along the longitudinal direction.

  In the present embodiment, semicircular elastic members (vibration isolation members) 41a and 41b are attached to the inner wall surfaces of the upper pipe member 31a and the lower pipe member 31b. The elastic members 41a and 41b are made of an elastic material such as rubber or sponge, for example, and the inner peripheral surface (the contact surface with the conveying screw 35) has a lower coefficient of friction than the elastic members 41a and 41b (sliding property). (Good) film material is laminated. In addition, you may surface-treat the internal peripheral surface of elastic member 41a, 41b with a material with a low friction coefficient instead of laminating | stacking a film material. Examples of the material having a low coefficient of friction include a fluororesin film and a coating agent.

  When viewed from the axial direction of the toner transport pipe 31, the inner peripheral surfaces of the elastic members 41a and 41b are concentric with the central axis O of the toner transport pipe 31 as the center, and the distance from the central axis O to the inner peripheral surface Is formed to be equal to or slightly larger than the outer diameter of the conveying blade 35a of the conveying screw 35.

  Further, when the pitch of the conveying blade 35a of the conveying screw 35 is L, the elastic members 41a and 41b are pasted to a length of L / 2 or more, and the elastic member 41a of the upper pipe member 31a and the lower pipe 31a The elastic member 41b is provided at a position that does not overlap in the axial direction. The conveying screw 35 is supported at the substantially central portion in the longitudinal direction by the elastic members 41a and 41b at the outer peripheral edge of the conveying blade 35a. At this time, the axis center of the rotation shaft 35 b of the conveying screw 35 substantially coincides with the central axis O of the toner conveying pipe 31.

  With this configuration, when the conveying screw 35 is warped, the direction of the warping exceeds the uppermost point with the rotation of the conveying screw 35, and even if an attempt is made to swing in the direction in which the warping is increased by the deflection of its own weight (radially outward), Since the outer peripheral edge of the conveying blade 35a contacts the elastic members 41a and 41b attached to the inner wall surface in the rotation direction, the wavy deformation in the radial direction of the conveying screw 35 due to the interaction between the warp and the deflection due to its own weight is suppressed. Is done. Therefore, the conveying screw 35 rotates with the elastic members 41a and 41b supported so that the rotation shaft 35b is substantially linear. Further, due to the silencing effect of the elastic members 41a and 41b made of an elastic material, it is possible to effectively suppress the generation of a striking sound due to a collision between the conveying screw 35 and the inner surface of the toner conveying pipe 31.

  Here, since the elastic members 41a and 41b are provided in a range of 1/2 (L / 2) or more of the pitch L of the conveying blade 35a, a part of the outer peripheral edge of the conveying blade 35a is always elastic member 41a. , 41b. Thereby, the collision sound between the inner wall surface of the toner transport pipe 31 and the transport screw 35 can be effectively reduced. Moreover, the lower part of the conveying screw 35 is reliably supported by the elastic member 41b.

  Further, since the elastic member 41a is formed at a position that does not overlap with the elastic member 41b in the longitudinal direction of the toner transport pipe 31, the length of the transport screw 35 is between the inner wall surface of the toner transport pipe 31 and the transport blade 35a. There will be a continuous gap in the direction. Therefore, the toner carried into the toner transport pipe 31 can move through this gap and is not blocked by the elastic members 41a and 41b.

  Therefore, it is possible to prevent toner clogging in the toner conveyance pipe 31 and the increase in the rotational torque of the conveyance screw 35 accompanying this. Further, since the rotation of the conveying screw 35 smoothly rotates without increasing, the generation of frictional heat due to the rotation of the conveying screw 35 can be suppressed, and the fluidity of the toner in the toner conveying pipe 31 is reduced. And solidification can be effectively suppressed.

  In the present embodiment, the elastic members 41a and 41b are provided only in the substantially central portion in the longitudinal direction of the toner conveyance pipe 31, but the elastic members 41a and 41b may be provided in a plurality of locations in the longitudinal direction of the toner conveyance pipe 31. . However, in most cases, the warp of the conveying screw 35 occurs in the central portion in the longitudinal direction, and even if the elastic members 41a and 41b are formed in the vicinity of both ends in the longitudinal direction, the effect of supporting the conveying screw 35 cannot be expected so much. . A sufficient effect can be expected if the elastic members 41 a and 41 b are formed so as to be opposed to a range within 1/3 of the entire length of the conveying screw 35 at a substantially central portion in the longitudinal direction of the conveying screw 35.

  In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in each of the above-described embodiments, the cleaning device 7 including the rubbing roller 21 and the cleaning blade 22 has been described. However, the toner conveying device 30 of the present invention includes, for example, the cleaning device 7 including only the cleaning blade 22 and the cleaning device 7. The present invention can be applied to various types of cleaning devices such as the cleaning device 7 having a fur brush instead of the blade 22.

  In each of the above embodiments, the transport screw 35 in which the spiral transport blades 35a are continuously provided around the rotation shaft 35b is used. However, the transport blade 35a is not limited to a spiral shape, and includes, for example, a plurality of A semicircular plate (a plate obtained by dividing a circular plate into two parts) may be alternately arranged around the rotation shaft 35b at a predetermined inclination angle to form the conveying blade 35a.

  In each of the above embodiments, the toner transport device 30 according to the present invention is disposed in the waste toner transport path from the cleaning device 7 to the waste toner bottle 37. However, for example, toner transport from the toner container 6 to the developing unit 5 is performed. The same applies to the route.

  The present invention can be used for a toner conveying device having a toner conveying pipe and a conveying screw disposed in the toner conveying pipe. By using the present invention, it is possible to suppress the generation of impact sound due to the collision between the conveying screw and the inner surface of the toner conveying pipe, and to effectively prevent the decrease in the fluidity and solidification of the toner due to the increase in the rotational load of the conveying screw. Can do.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Photosensitive drum 7 Cleaning apparatus 21 Rub roller 22 Cleaning blade 30 Toner conveyance apparatus 31 Toner conveyance pipe 31a Upper pipe member (1st pipe member)
31b Lower pipe member (second pipe member)
32 Toner carrying port 33 Toner discharging port 35 Conveying screw 35a Conveying blade 35b Rotating shaft 37 Waste toner bottle 40a First rib (convex portion)
40b 2nd rib (convex part)
41a, 41b Elastic member (convex part)

Claims (5)

A conveying screw having a rotating shaft and a conveying blade formed on the outer peripheral surface of the rotating shaft;
A toner conveying pipe having a circular cross section in which the conveying screw is rotatably arranged;
A toner conveying device comprising:
The toner conveying pipe is formed by combining a first pipe member that constitutes a half of the outer peripheral surface viewed from the axial direction and a second pipe member that constitutes the remaining half of the outer peripheral surface;
On the inner wall surfaces of the first pipe member and the second pipe member, a convex part having a semicircular arc shape in cross section having an inner peripheral surface concentric with the inner wall surface around the central axis of the toner conveying pipe is provided. pipe is formed at a position not overlapping with each other in the axial direction of the distance from the central axis to the inner peripheral surface equal to the radius of the conveying vanes, rather slightly larger than the radius of the conveying vanes,
The convex portion is formed at least at one location on the inner wall surface of the first pipe member, at a plurality of locations on the inner wall surface of the second pipe member, with a first rib formed along the rotation direction of the conveying wing. Toner transporting comprising second ribs formed along the rotation direction of the transporting wings at intervals of less than one pitch of the transporting wings so as to sandwich the first ribs in the axial direction of the toner transporting pipe apparatus. It said first pipe member and the second pipe member, the toner conveying device according to claim 1, characterized in that the pipe member and the lower pipe member on each constituting the upper half and a lower half of said toner conveying pipe . 3. The toner conveying device according to claim 1 , wherein the second rib is formed at a pitch that is ½ of a pitch of the conveying wing . 4. The said convex part is formed so that it may oppose the range within 1/3 of the full length of the said conveyance screw in the approximate center part of the longitudinal direction of the said conveyance screw . The toner conveying device according to any one of the above. An image forming apparatus on which the toner conveying device according to claim 1 is mounted .

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