Toner conveyance device

Abstract

To provide a toner conveying device that can attach a conveyance coil member to a rotational drive member, while reducing the risk that the conveyance coil member is plastically deformed when the conveyance coil member is assembled to the rotational drive member.SOLUTION: A screw driving member 17 includes a hole part 172 into which a second extension part 164 of a toner conveying screw 16 is inserted, and is provided with a regulation unit 173 such that, in a width direction of a shank 171 of the screw driving member 17, the height in an insertion direction of the second extension part 164 becomes higher in one area along a hole part 172 than the other area along the hole part. An end turn part 162 of the toner conveying screw 16 is configured such that winding can be started from a first extension part 163 toward a side where the regulation unit 173 is not provided.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a toner conveying device including a conveying coil member formed of a wire wound in a spiral shape.

Background Art

[0002] In an electrophotographic image forming apparatus, a toner image formed on an image carrier such as a photosensitive drum or an intermediate transfer member is transferred onto a recording material such as paper or a plastic sheet to form an image. In a conventional image forming apparatus, a configuration is used in which transfer residual toner (recovered toner) on the image carrier is removed by a cleaning blade and recovered into a drum cartridge. This recovered toner is conveyed to a recovered toner container outside the drum cartridge by a toner conveying member installed near the cleaning blade from the viewpoint of extending the life of the process cartridge. As the toner conveying member, for example, a toner conveying screw (also referred to as a conveying coil member) formed in a cylindrical (spring) shape by winding a metal wire in a spiral shape may be used. This toner conveying screw is disposed in a cylindrical toner conveying passage and is rotationally driven by a drive system. As the rotational driving force of this type of toner conveying member, in addition to using an independent drive source, there are cases where the rotational driving force is transmitted from a drive system that rotationally drives the photosensitive drum in the drum cartridge via a drum gear or the like. As the toner conveying member, a screw formed by molding a resin material in a spiral shape around a central axis (made of metal or resin) is also known, but the cylindrical (spring) shape screw as described above has an advantage that the toner conveying device can be configured to be small, lightweight, simple, and inexpensive.

[0003] In Patent Document 1, as a holding configuration of a toner conveyance screw made of a spring and a screw drive member (also called a rotational drive member), an L-shaped bent portion is provided at the end of the toner conveyance screw and inserted into a hole provided in the screw drive member. Further, in the configuration of Patent Document 1, a shaft portion having a smaller diameter than the inner diameter of the winding portion provided in the screw drive member is inserted into the winding portion on the screw drive member side of the toner conveyance screw. As a result, the deviation and inclination of the rotation axes of the toner conveyance screw and the screw drive member are reduced, and it is possible to reduce the rubbing noise with peripheral members due to the rotational vibration of the screw drive member and the toner conveyance screw. Furthermore, with the above configuration, the toner conveyance screw is configured not to easily fall off from the screw drive member, and it is possible to prevent unexpected dropout of the two parts.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the configuration where the shaft shape of the rotary drive member is inserted into the spiral winding portion of the spring-made conveyance coil member described above to prevent the two components from falling off, it is necessary to deform and assemble the conveyance coil member or the rotary drive member. If the force required for deformation is large, the conveyance coil member will undergo plastic deformation and the amount of rotational runout will increase. Then, during the rotation operation, the outer periphery of the conveyance coil member or the rotary drive member may rub against other components, generating abnormal noise. In the configuration of Patent Document 1, it is necessary to deform the conveyance coil member during assembly. Also, it is conceivable to provide flexible claw portions on the rotary drive member side and bend the claw portions of the rotary drive member by the conveyance coil member for assembly. However, in this case, it is necessary to insert the conveyance coil member in the rotational axis direction while it receives the reaction force when bending the claw portions of the rotary drive member. Therefore, depending on the setting of the amount of deformation required during assembly, there is a possibility of deforming the conveyance coil member. Furthermore, if the spring wire diameter is made thinner from the perspective of reducing the size and weight of the device, the allowable stress of the conveyance coil member will decrease, and the risk of the conveyance coil member undergoing plastic deformation will further increase.

[0006] Therefore, an object of the present invention is to provide a toner conveyance device capable of attaching a conveyance coil member to a rotary drive member while reducing the risk of plastic deformation of the conveyance coil member when assembling the conveyance coil member to the rotary drive member.

Means for Solving the Problems

[0007] The configuration of the present invention for solving the above problems includes a conveyance path for conveying toner, a conveyance coil portion formed by spirally winding a wire around a rotation axis, a conveyance coil member rotatably provided in the conveyance path, and a rotation drive member connected to the conveyance coil member to rotate the conveyance coil member. The conveyance coil member is connected to the conveyance coil portion on the upstream side in the toner conveyance direction of the conveyance coil portion, and includes a seated winding portion consisting of at least one turn or more, a first extending portion connected to the seated winding portion and extending in the rotation axis direction, and a second extending portion extending in the radial direction of the conveyance coil portion from the first extending portion. The rotation drive member includes a shaft portion inserted into the seated winding portion, a hole portion into which the second extending portion is inserted, a first region adjacent to the hole portion in the width direction of the shaft portion orthogonal to the insertion direction of the second extending portion, a second region disposed on the opposite side of the first region with respect to the hole portion, and a downstream region disposed on the downstream side of the hole portion in the toner conveyance direction. The height of the first region in the insertion direction is configured to be higher than the second region and the downstream region, and the seated winding portion is configured to start winding from the first extending portion toward the side opposite to the first region.

Effect of the Invention

[0008] According to the present invention, it is possible to provide a toner conveyance device capable of attaching a conveyance coil member to a rotation drive member while reducing the risk of plastic deformation of the conveyance coil member when assembling the conveyance coil member to the rotation drive member.

Brief Description of the Drawings

[0009]

Figure 1

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Figure 12

Figure 13

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, components having the same reference numerals have the same configuration or operation, and duplicate descriptions thereof will be omitted as appropriate. Note that the dimensions, materials, shapes, relative positions, etc. of the components are not intended to limit the scope of application of this technical idea only to those, unless otherwise specifically described.

[0011] (Overall Configuration and Operation of the Image Forming Apparatus) First, the overall configuration and operation of the image forming apparatus will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 of this embodiment is a tandem type image forming apparatus employing an intermediate transfer method that can form a full-color image using an electrophotographic method.

[0012] The image forming apparatus 1 of this embodiment includes an image forming unit that forms toner images of each color of Y (yellow), M (magenta), C (cyan), and K (black). The configurations and operations of these image forming units are substantially the same except that the colors of the toners used are different. Therefore, hereinafter, when there is no particular need for distinction, the Y, M, C, and K at the end of the symbol indicating an element for any color are omitted, and the elements will be comprehensively described.

[0013] The image forming unit has a photosensitive drum 12 (photosensitive member) as an image carrier that is a drum-shaped (cylindrical) electrophotographic photosensitive member. The photosensitive drum 12 is rotationally driven by transmission of a driving force from driving means (not shown) provided in the image forming apparatus main body 1. In the image forming unit, the following means are arranged in order along the circumferential direction of the photosensitive drum 12. First, a charging roller 13, which is a rotatable roller-shaped charging member as the charging means, is arranged. Next, the surface of the photosensitive drum 12 is arranged to receive exposure by an exposure device (laser scanner device) 22 as the exposure means (electrostatic latent image forming means). Next, a developing device 20 is arranged as the developing means. Toner is supplied to the developing device 20 from a toner bottle 21 as a toner storage container through a toner conveyance path (not shown). Next, a primary transfer roller 31, which is a roller-shaped primary transfer member as the primary transfer means, is arranged. Next, a drum cleaning blade 14 is arranged as the cleaning means for the photosensitive member. In addition, in the image forming unit, a cleaning roller 15, which is a roller-shaped charging cleaning member as the cleaning means for the charging member, is arranged in contact with the charging roller 13. In this embodiment, the charging roller 13 is brought into contact with the surface of the photosensitive drum 12 with a predetermined pressing force by urging means such as a spring, and rotates following the rotation of the photosensitive drum 12.

[0014] Also, in this embodiment, the cleaning roller 15 is brought into contact with the surface of the charging roller 13 with a predetermined pressing force by urging means such as a spring, and rotates following the rotation of the charging roller 13.

[0015] Further, the image forming apparatus 1 has an intermediate transfer belt 30 formed of an endless belt body as an intermediate transfer member so as to contact each photosensitive drum 12 of each image forming unit. The intermediate transfer belt 30 is wound around a plurality of support rollers with a predetermined tension. The primary transfer roller 31 is disposed at a position facing each photosensitive drum 12 on the inner peripheral surface side (back surface side) of the intermediate transfer belt 30. The primary transfer roller 31 is pressed against the photosensitive drum 12 via the intermediate transfer belt 30, and forms a primary transfer portion where the intermediate transfer belt 30 and the photosensitive drum 12 are in contact. The primary transfer roller 31 rotates in a driven manner as the intermediate transfer belt 30 rotates. Further, a secondary transfer roller 32, which is a roller-shaped secondary transfer member as secondary transfer means, is disposed at a position facing the secondary transfer counter roller 33 on the outer peripheral surface side (front surface side) of the intermediate transfer belt 30. The secondary transfer roller 32 is pressed against the secondary transfer counter roller 33 via the intermediate transfer belt 30, and forms a secondary transfer portion where the intermediate transfer belt 30 and the secondary transfer roller 32 are in contact. Further, a belt cleaning device 40 as intermediate transfer body cleaning means is disposed at a position facing the tension roller 34 on the outer peripheral surface side of the intermediate transfer belt 30. The intermediate transfer belt 30 is formed in an endless shape by a dielectric resin such as polyimide.

[0016] In addition, the image forming apparatus 1 is provided with a feed conveyance roller 51 for a recording material P such as recording paper, a fixing device 70 for fixing the toner image to the recording material P, and the like.

[0017] At the time of image formation, the surface of the photosensitive drum 12 that is rotationally driven is uniformly charged to a predetermined potential of a predetermined polarity by the charging roller 13. In this embodiment, a voltage is applied from a high-voltage power source (not shown) to the charging roller 13, and discharge occurs with respect to the surface of the photosensitive drum 12, whereby the surface of the photosensitive drum 12 is charged.

[0018] After the surface of the photosensitive drum 12 is uniformly charged, the surface of the photosensitive drum 12 is scanned and exposed by the laser scanner 22 based on the signal of the image information, and an electrostatic latent image is formed on the photosensitive drum 12. The latent image formed on the photosensitive drum 12 is developed into a toner image using toner as a developer by the developing device 20. In this embodiment, the normal charging polarity of the toner is negative. The developing device 20 has a developing sleeve as a developer carrier that carries the toner and conveys it to the opposing portion (developing position) with the photosensitive drum 12. The developing sleeve is rotationally driven. During development, a predetermined developing voltage is applied to the developing sleeve from a high-voltage power source (not shown) as a developing power source.

[0019] The toner image formed on the photosensitive drum 12 is transferred (primary transfer) to the surface of the intermediate transfer belt 30 by the action of the primary transfer roller 31 in the primary transfer section. At this time, a primary transfer voltage, which is a voltage of the opposite polarity (positive polarity in this embodiment) to the charging polarity of the toner during development, is applied to the primary transfer roller 31 from a high-voltage power source (not shown). When forming a full-color image, the above-described operation is performed in each image forming section, and the toner images of each color of Y (yellow), M (magenta), C (cyan), and K (black) formed on each photosensitive drum 12 are transferred onto the intermediate transfer belt 30 so as to be sequentially superimposed.

[0020] After the transfer, the small amount of transfer residual toner remaining on the photosensitive drum 12 is removed by the cleaning blade 14 as a cleaning means and collected in the toner conveyance path 181.

[0021] On one hand, the recording material P is fed one by one from the paper feed cassette 50 and conveyed to the resist roller pair 60. Then, the resist roller pair 60 conveys the recording material P between the intermediate transfer belt 30 and the secondary transfer outer roller 33 in synchronization with the toner image on the intermediate transfer belt 30. The color toner image on the intermediate transfer belt 30 is transferred (secondary transfer) to the surface of the recording material P by the action of the secondary transfer roller 32 in the secondary transfer section. When this recording material P passes through the secondary transfer section, a secondary transfer voltage, which is a voltage of the opposite polarity to the charging polarity of the toner during development, is applied to the secondary transfer roller 32 from a high-voltage power source (not shown). After transfer, the small amount of transfer residual toner remaining on the intermediate transfer belt 30 is removed and recovered by the belt cleaning device 40 and prepared for the next image formation again. The toner image transferred onto the recording material P is fixed by being heated and pressurized by the fixing device 70 and discharged onto the paper discharge tray 90 by the paper discharge roller pair 80.

[0022] (Drum Cartridge) Next, the configuration of the drum cartridge 10 as a photoreceptor unit will be described with reference to FIGS. 2 to 4.

[0023] The drum cartridge 10 of this embodiment includes a photosensitive drum 12 as a photoreceptor, a charging roller 13 as a charging member, a cleaning roller 15 as a charging cleaning member, and a cleaning blade 14 as a cleaning member. And the drum cartridge 10 of this embodiment has a configuration in which these are integrally held by a drum frame 11 as a frame body. Also, it is configured to be detachable from the image forming apparatus main body 1 by sliding it along the longitudinal direction from the image forming apparatus main body 1, and can be replaced for maintenance and the like.

[0024] On the drum frame 11, a photosensitive drum 12 is rotatably held about a rotation axis via a bearing (not shown). The photosensitive drum 12 is provided with a coupling 121 for receiving a driving force from a motor as a driving source (not shown) provided in the image forming apparatus main body 1 when mounted on the image forming apparatus main body 1 and rotating. The charging roller 13 is rotatably supported by a charging roller bearing (not shown) and is pressed against the photosensitive drum 12 by a pressing spring (not shown). The cleaning roller 15 is rotatably supported by a cleaning roller bearing (not shown) and is pressed against the charging roller 13 by a pressing spring (not shown). Further, on the drum frame 11, a cleaning blade 14 as a cleaning member for cleaning the surface of the photosensitive drum 12 is fixed so as to contact the surface of the photosensitive drum 12 in a counter direction to the rotation direction of the photosensitive drum 12 during image formation. Further, in the vicinity of the cleaning blade 14, a toner conveyance path 181 for recovering and conveying the transfer residual toner removed from the surface of the photosensitive drum 12 by the cleaning blade 14 is provided. In the toner conveyance path 181, a toner conveyance screw 16 as a conveyance member (conveyance coil member) for conveying the recovered toner outside the drum cartridge 10 is provided. The toner conveyed outside the drum cartridge 10 by the toner conveyance screw 16 is recovered in a recovered toner container (not shown) provided in the image forming apparatus main body 1. At the longitudinal end of the photosensitive drum 12, a gear 122 as a rotating member fixed so as to rotate integrally with the photosensitive drum 12 about the rotation axis of the photosensitive drum 12 is provided. Between the photosensitive drum 12 and the toner conveyance screw 16, driving transmission means 191, 192 and a screw driving member 17 as a rotation driving member are provided. The toner conveyance screw 16 is attached so as to be driven and transmitted from the screw driving member 17. Further, the screw driving member 17 is provided with a toner sealing member 182 for preventing the toner in the recovery portion from entering the upstream side in the toner conveyance direction of the toner conveyance screw 16. When the photosensitive drum 12 rotates, the rotational force of the gear 122 that rotates integrally therewith is driven and transmitted to the toner conveyance screw 16 via the driving transmission means 191, 192 and the screw driving member 17.As a result, the toner conveyance screw 16 rotates, and the transfer residual toner collected in the collection unit can be conveyed outside the drum cartridge 10.

[0025] With the above configuration, when the photosensitive drum 12 rotates by receiving a driving force from a driving source (not shown) provided in the image forming apparatus main body 1, the charging roller 13 is driven to rotate by the frictional force with the photosensitive drum 12. Further, when the charging roller 13 rotates, the cleaning roller 15 is driven to rotate by the frictional force with the charging roller 13. Also, the toner conveyance screw 16 is driven to rotate by being transmitted from the gear 122.

[0026] (First Embodiment) The first embodiment will be described with reference to FIGS. 5 to 11. Note that in the figures after FIG. 5, the toner sealing member 182 is not shown for convenience of explanation.

[0027] As shown in FIG. 5, the toner conveyance screw 16 is held by the screw drive member 17 such that the rotation axis thereof substantially coincides with the rotation axis of the screw drive member 17.

[0028] As shown in FIG. 6, the toner conveyance screw 16 as a conveyance coil member for conveying toner has a conveyance coil portion 161 that conveys toner in the rotation axis direction along with the rotation operation. Also, the toner conveyance screw 16 has a spiral portion 162 provided by being connected to the upstream end portion in the toner conveyance direction of the conveyance coil portion 161 of the conveyance coil portion. Further, the toner conveyance screw 16 has a first straight portion 163 as a first extended portion that is connected to the spiral portion 162 and extends upstream in the toner conveyance direction. Furthermore, the toner conveyance screw 16 has a second straight portion 164 as a second extended portion that is connected to the first straight portion 163 and is bent at a right angle from the first straight portion toward the rotation center direction of the toner conveyance screw 16.

[0029] As shown in FIG. 7, the screw drive member 17 has a shaft portion 171 inserted into the winding portion 162 of the toner conveying screw 16 and a hole portion 172 into which the second straight portion 164 is inserted. When the screw drive member 17 rotates, rotation is transmitted from the inner wall of the hole portion 172 to the second straight portion 164 of the toner conveying screw 16, causing the toner conveying screw 16 to rotate. Further, by inserting the shaft portion 171 into the winding portion 162, the rotational axes of the toner conveying screw 16 and the screw drive member 17 are substantially aligned. In this embodiment, the hole portion 172 is a through hole and has an elongated hole shape along the rotational axis direction of the screw drive member 17. The toner conveying screw 16 is biased upstream in the toner conveying direction by the reaction force of toner conveyance. However, as it moves closer to the upstream side, the insertion amount of the shaft portion 171 into the winding portion 162 increases, reducing the amount of deviation of the rotational axis of the toner conveying screw 16. Also, even when the toner conveying screw 16 is positioned closest to the downstream side in the conveying direction within the hole portion 172, the end position of the hole portion 172 is provided at a position where the shaft portion 171 is inserted into the winding portion 162. This makes it possible to hold the toner conveying screw 16 so that it does not easily fall off from the screw drive member 17. As a result, after pre-assembling the toner conveying screw 16 and the screw drive member 17, they can be assembled integrally into the drum cartridge 10, which is advantageous from the viewpoint of assemblability.

[0030] Also, as shown in FIG. 7, the screw drive member 17 has a first fitting portion 175 rotatably fitted and supported with respect to the drum frame 11, and a second fitting portion 176 rotatably fitted and supported with respect to a screw drive member bearing (not shown). By being supported in a two-point manner by the two fitting portions, tilting of the rotational axis of the screw drive member 17 is suppressed. Further, the screw drive member 17 has a gear portion 174 and is driven and transmitted from the gear 122 provided on the photosensitive drum 12 via the drive transmission means 191 and 192 shown in FIG. 3.

[0031] Next, the assembly of the toner conveyance screw 16 and the screw drive member 17 will be described with reference to FIGS. 5 and 8 to 11. As described above, the toner conveyance screw 16 is held so as not to easily fall off from the screw drive member 17. In order to assemble the toner conveyance screw 16 to the screw drive member 17 as shown in FIG. 5, it is necessary to deform a part of the toner conveyance screw 16 for assembly.

[0032] As the first assembling direction, the following directions can be considered. That is, as shown in Fig. 8(a), the second straight portion 164 of the toner conveying screw 16 is inserted into the hole portion 172 of the screw driving member 17 in a direction in which the rotation axis of the toner conveying screw 16 and the rotation axis of the screw driving member 17 are substantially orthogonal. Then, with the second straight portion 164 as the rotation axis, it is rotated 90° clockwise (in the direction of arrow D1 in Fig. 8(a)) with respect to the screw driving member 171. By doing so, the winding portion 162 of the toner conveying screw 16 is assembled so as to overcome the shaft portion 171 of the screw driving member 17. At this time, the toner conveying screw 16 is deformed so as to widen the distance L1 from the point T1 where the shaft portion 171 contacts on the assembling locus on the winding portion 162 shown by L1 in Fig. 9(a) to the second straight portion 164 by a predetermined amount L2, making the assembly possible. When trying to assemble by rotating in the above-described direction, the force for deforming the toner conveying screw 16 in order for the winding portion 162 to overcome the shaft portion 171 acts in the direction shown by arrow F1 in Fig. 9(a) at the position of T1. At this time, the point T1 is a point near 3 / 4 of a turn of the first turn of the winding portion 162. Due to the force acting on the point T1, the toner conveying screw 17 is deformed so that the distance L1 expands by the deformation amount L2 required for assembly, and returns to the original length L1 after overcoming the shaft portion 171. Fig. 9(b) is a schematic diagram showing the state in which the toner conveying screw in the first assembling direction is deformed by the deformation amount L2. The main deformation at this time is the deformation due to the spring property of the winding portion 162 in the toner conveying direction from the position of the point T1 (Fig. 9(a)) to the position of the point T2 (Fig. 9(b)), that is, the angle θ1 (Fig. 9(a)) of the winding portion 162 is deformed to θ2 (Fig. 9(b)). By setting the deformation amount L2 to an amount that can be deformed by the spring property of the winding portion 162, it is possible to reduce the risk of plastic deformation of the toner conveying screw 16.

[0033] Next, as a second assembling direction, as shown in Fig. 10(a), an assembling direction can be considered in which the toner conveying screw 16 is set on the screw driving member 17 in the direction opposite to that in Fig. 8(a) and rotated counterclockwise (in the direction of arrow D2 in Fig. 10(a)). At this time, the force for deforming the toner conveying screw 16 in order for the coiling portion 162 to overcome the shaft portion 171 acts in the direction indicated by arrow F2 in Fig. 11(a) at a position near the 1 / 4 turn of the first turn of the coiling portion 162 shown by T3 in Fig. 11(a). This is because the shaft portion 171 contacts the point T3 on the assembling locus. At this time, as shown in Fig. 11(b), the toner conveying screw 16 needs to be deformed so that the distance L3 from the second straight portion 164 to the coiling portion 162 expands by the deformation amount L2 required for assembly. Fig. 11(b) is a schematic diagram showing the state in which the toner conveying screw in the second assembling direction is deformed by the deformation amount L2. In the second assembling direction, instead of the deformation due to the spring property of the coiling portion 162, the second straight portion 164 and the entire coiling portion 162 are inclined with respect to the first straight portion 163 and deformed by L2. That is, the angle θ3 (Fig. 11(a)) between the first straight portion 163 and the coiling portion 162 is deformed to θ4 (Fig. 11(b)). In this case, a large force is applied to the connecting portion between the first straight portion 163 and the second straight portion 164, and the connecting portion between the first straight portion 163 and the coiling portion 162, and there is a risk that the toner conveying screw 16 will be plastically deformed.

[0034] In this embodiment, in order to avoid plastic deformation of the toner conveyance screw 16 in the second assembling direction described above, a restricting portion 173 is provided on the screw driving member 17. As shown in FIG. 7, the screw driving member 17 has a first region A adjacent to the hole portion 172 in the width direction of the shaft portion 171 (radial direction of the screw driving member 17) orthogonal to the insertion direction of the second straight portion 164. Further, the screw driving member 17 has a second region B disposed on the side opposite to the first region A with respect to the hole portion 172, and a downstream region C provided on the downstream side of the hole portion 172 in the toner conveyance direction of the toner conveyance screw 16. In this embodiment, the restricting portion 173 is provided in the first region A, and the restricting portion 173 is not provided in the second region B and the third region C. For this reason, the height of the first region A in the insertion direction of the second straight portion 164 is configured to be higher than those of the second region B and the third region C.

[0035] The effect obtained by the restricting portion 173 will be described. FIG. 8(b) is a view of the state in which the toner conveyance screw 16 is set on the screw driving member 17 in the first assembling direction described above, and FIG. 10(b) is a view of the state in which the toner conveyance screw 16 is set on the screw driving member 17 in the second assembling direction described above, as viewed from the rotation axis direction (Y direction) of the screw driving member 17. Note that the X, Y, and Z directions used in the following description are as shown in FIGS. 8 and 10. That is, the Y direction is the rotation axis direction of the screw driving member 17, the Z direction is the extending direction of the second straight portion 164 of the toner conveyance screw 16, and the second straight portion 164 is inserted into the hole portion 172 from the +Z direction to the -Z direction. The X direction is a direction orthogonal to the Y direction and the Z direction.

[0036] In the assembled set state in the first assembling direction shown in Fig. 8(b), the rotation axis 16A of the toner conveying screw 16 is at a position of -Z1 in the Z direction with respect to the Z-direction center position 171Z of the shaft portion 171 of the screw driving member 17. On the other hand, in the assembled set state in the second assembling direction shown in Fig. 10(b), the rotation axis 16A of the toner conveying screw 16 is at a position of +Z2 in the Z direction with respect to the Z center position 171Z of the shaft portion 171 of the screw driving member 17. This is because the regulating portion 173 regulates the Z-direction intrusion amount of the tip position of the second straight portion 164 with respect to the hole portion 172 in the assembled set state so that it is smaller by Z1 + Z2 in the second assembling direction than in the first assembling direction. The regulating portion 173 is a part of a cylindrical shape with a radius R2 and coaxial with the shaft portion 171. Further, the shaft portion 171 has a cross boss shape with an outer peripheral surface of a cylindrical shape with a radius R1, and the relationship R3 > R1 holds. Also, when the distance from the rotation axis 16A of the toner conveying screw 16 to the inside of the first straight portion 163 is R3, R3 is equal to the inner diameter radius of the winding portion 162, and the relationship R2 > R3 > R1 holds. Furthermore, when the Z-direction distance between the apex of the regulating portion 173 and the center of the shaft portion 171 is 173Z, the relationship 173Z > R3 holds.

[0037] Also, as shown in Fig. 11, in the second assembling direction, a force acts on the winding portion 162 in the direction of arrow F2. Arrow F2 has a component in the direction in which the second straight portion 164 comes out of the hole portion 172 (+Z direction in Fig. 10), and the greater the force required for assembly, the easier it is for the second straight portion 164 to move in the direction of coming off from the hole portion 172. As a result, the assembled set state is configured to be canceled by the second straight portion 164 coming out of the hole portion 172 before the toner conveying screw 16 undergoes plastic deformation. Thereby, it becomes possible to suppress the plastic deformation of the toner conveying screw 16. By shifting the Z-direction intrusion amount of the tip position of the second straight portion 164 in the assembled set state in the second assembling direction to the side where it is smaller by the regulating portion 173, an effect of making it easier to cancel the set state than when there is no regulating portion 173 is obtained.

[0038] Further, the restricting portion 173 is disposed only on one side of the hole portion 172 in the X direction. In this embodiment, in a state where the toner conveying screw 16 and the screw driving member 17 shown in FIG. 5 are assembled, the restricting portion 173 is disposed on the side opposite to the winding start direction of the winding portion 162 from the first straight portion 163. That is, as viewed from the first straight portion 163 in FIG. 5, the winding portion 162 is wound toward the +X direction of the hole portion 172, and the restricting portion 173 is provided in the -X direction of the hole portion 172. That is, the winding portion 162 is configured to start winding from the first straight portion 163 toward the side opposite to the first region A. By disposing the restricting portion 173 in such a relationship, the restricting portion 173 acts when assembled in the second assembling direction. On the other hand, in the assembly in the first assembling direction, it does not affect the assembly work even during and after the assembly set.

[0039] Furthermore, the hole portion 172 is a through hole, and the second straight portion 164 can be inserted from either side of the hole portion 172. Therefore, the restricting portion 173 is disposed so as to be point-symmetrical with respect to the rotation axis center of the screw driving member 17 in the X-Z plane. As a result, the above-described effect can be obtained regardless of which side of the through hole 172 the second straight portion 164 is inserted from. However, the hole portion 172 does not have to be a through hole.

[0040] As described above, it becomes possible to avoid the assembly in the second assembly direction in which the risk of plastic deformation of the toner conveying screw 16 is high by the restricting portion 173. As a result, it is possible to reduce the risk of generation of abnormal noise due to rubbing between the outer peripheral parts of the toner conveying screw 16 and the screw driving member 17 during the rotation operation, which is caused by the plastic deformation of the toner conveying screw.

[0041] (Second Embodiment) Next, a second embodiment will be described with reference to FIGS. 12 and 13. Note that the description of the portions overlapping with those described in the first embodiment will be omitted, and the portions having a configuration different from that of the first embodiment will be described.

[0042] FIG. 12 is a perspective view of the screw drive member 17 of the second embodiment, and FIG. 13 is a cross-sectional view taken longitudinally of the hole 172 in a state where the toner conveying screw 16 and the screw drive member 17 of the second embodiment are assembled.

[0043] In the second embodiment, the screw drive member 17 does not have a gear portion 17 and has a D-cut portion 177 as a drive receiving portion, and is configured to rotate by receiving a driving force from a driving source (not shown). Further, the hole 172 into which the second straight portion 164 of the toner conveying screw 16 is inserted is not a long hole, but has a hole shape with a diameter larger than the wire diameter of the toner conveying screw 16. Furthermore, the hole 172 is not a through hole, and the toner conveying screw 16 can be inserted into the hole 172 only from one direction. Therefore, the restricting portion 173 needs to be provided only at one location on the entrance side of the hole, and the effects described in the first embodiment can be obtained.

[0044] As described above, by providing the restricting portion 173 on the screw drive member 17, it becomes possible to avoid assembling the toner conveying screw 16 from a direction in which there is a high risk of plastic deformation of the toner conveying screw 16 when assembling the toner conveying screw 16 to the screw drive member 17. As a result, it is possible to reduce the risk of generation of abnormal noise due to rubbing between the toner conveying screw 16 and the outer peripheral components of the screw drive member 17 during the rotational operation, which is caused by plastic deformation of the toner conveying screw 16. As a result, it becomes possible to provide a toner conveying device with reduced noise compared to the prior art.

Description of Reference Numerals

[0045] 10 Drum cartridge 12 Photosensitive drum (photoconductor) 14 Cleaning blade 16 Toner conveying screw 161 Conveying coil portion 162 Winding portion 163 First straight portion 164 Second straight portion 17 Screw drive member 171 Shaft portion 172 Hole 173 Regulation section 173 Z-direction distance of the regulation section from the center of the Z-axis section 174 Gear section 181 Toner conveyance path 191, 192 Drive transmission means R3 Radial distance from the rotation axis of the toner conveyance screw to the inside of the first straight section

Claims

1. A conveyance path for conveying toner, a conveyance coil part formed by spirally winding a wire around a rotation axis, a conveyance coil member rotatably provided in the conveyance path, a rotation drive member connected to the conveyance coil member to rotate the conveyance coil member, wherein the conveyance coil member, in the toner conveyance direction of the conveyance coil part, is connected to the conveyance coil part on the upstream side, and has a sitting winding part composed of at least one turn or more, a first extending part connected to the sitting winding part and extending in the rotation axis direction, a second extending part extending in the radial direction of the conveyance coil part from the first extending part, wherein the rotation drive member, has a shaft part inserted into the sitting winding part, a hole part into which the second extending part is inserted, a first region adjacent to the hole part in the width direction of the shaft part orthogonal to the insertion direction of the second extending part, a second region arranged on the side opposite to the first region with respect to the hole part, a downstream region arranged on the downstream side of the hole part in the toner conveyance direction, the height of the first region in the insertion direction is configured to be higher than the second region and the downstream region, and the sitting winding part is configured to start winding from the first extending part toward the side opposite to the first region. A toner conveyance device characterized by this.

2. The height of the first region in the insertion direction with respect to the rotation center of the rotation drive member is higher than the inner radius of the sitting winding part. The toner conveyance device according to Claim 1, characterized by this.

3. The height of the second region and the downstream region in the insertion direction with respect to the rotation center of the rotation drive member is lower than the inner radius of the sitting winding part. The toner conveyance device according to Claim 1 or 2, characterized by this.

4. The hole part is a through hole, and the rotation drive member has a third region that is point-symmetrical to the first region with respect to the rotation axis center of the rotation drive member, and a fourth region that is point-symmetrical to the second region. The toner conveyance device according to any one of Claims 1 to 3, characterized by this.

5. The first region is a part of a cylindrical shape coaxial with the rotation drive member, and the radius of the cylindrical shape is larger than the inner radius of the sitting winding part. The toner conveyance device according to any one of Claims 1 to 4, characterized by this.

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