JP7690294B2 - Toner conveying device - Google Patents

Description

The present invention relates to a toner transport device equipped with a transport coil member formed from a spirally wound wire.

In an electrophotographic image forming apparatus, a toner image formed on an image carrier such as a photosensitive drum or an intermediate transfer body is transferred to a recording material such as paper or a plastic sheet to form an image. In a conventional image forming apparatus, a cleaning blade is used to remove residual toner (recovered toner) from the image carrier and recover it in a drum cartridge. From the viewpoint of extending the life of the process cartridge, this recovered toner is transported to a recovered toner container outside the drum cartridge by a toner transport member installed near the cleaning blade. As a toner transport member, for example, a toner transport screw (also called a transport coil member) formed into a cylindrical (spring) shape by winding a metal wire in a spiral shape may be used. This toner transport screw is disposed in a cylindrical toner transport passage and is driven to rotate by a drive system. The rotational drive force of this type of toner transport member may be an independent drive source, or the rotational drive force may be transmitted from the drive system that drives the photosensitive drum in the drum cartridge via a drum gear or the like. A known toner transport member is a screw in which a resin material is formed into a spiral shape around a central axis (made of metal or resin), but the cylindrical (spring) shaped screw described above has the advantage that the toner transport device can be constructed small, lightweight, and simply and inexpensively.

Patent document 1 discloses a holding configuration for a spring-made toner transport screw and a screw drive member (also called a rotation drive member), in which an L-shaped bent shape is provided at the end of the toner transport screw and inserted into a hole provided in the screw drive member. In addition, in the configuration of Patent document 1, a shaft portion with a smaller diameter than the inner diameter of the seat winding portion provided in the screw drive member is inserted into the seat winding portion of the toner transport screw on the screw drive member side. This reduces the misalignment and inclination of the rotation axes of the toner transport screw and the screw drive member, making it possible to reduce the friction noise between the screw drive member and the surrounding members due to the rotational vibration of the screw drive member and the toner transport screw. Furthermore, with the above configuration, the toner transport screw is configured not to easily fall off the screw drive member, making it possible to prevent the two parts from falling off unexpectedly.

JP 2017-44776 A

However, in the configuration in which the shaft shape of the rotation drive member is inserted into the seat winding portion of the spring-made transport coil member described above to prevent the two parts from falling off, it is necessary to deform the transport coil member or the rotation drive member during assembly. If the force required for deformation is large, the transport coil member will undergo plastic deformation, and the amount of rotational runout will increase. Then, during rotation, the outer periphery of the transport coil member or the rotation drive member may rub against other parts, causing abnormal noise. In the configuration of Patent Document 1, it is necessary to deform the transport coil member during assembly. It is also possible to provide a flexible claw portion on the rotation drive member side and assemble the member by bending the claw portion of the rotation drive member with the transport coil member. However, in this case, it is necessary to insert the transport coil member in the direction of the rotation axis while receiving the reaction force when bending the claw portion of the rotation drive member. Therefore, depending on the setting of the deformation amount required during assembly, there is a possibility that the transport coil member will be deformed. Furthermore, if the spring wire diameter is reduced from the viewpoint of reducing the size and weight of the device, the allowable stress of the transport coil member will be reduced, and the risk of plastic deformation of the transport coil member will be further increased.

The object of the present invention is to provide a toner transport device that can attach a transport coil member to a rotary drive member while reducing the risk of plastic deformation of the transport coil member when assembling the transport coil member to the rotary drive member.

The configuration of the present invention for solving the above problem includes a transport path for transporting toner, a transport coil section formed by winding a wire in a spiral shape around a rotation axis, a transport coil member rotatably provided in the transport path, and a rotation drive member connected to the transport coil member and rotating the transport coil member, the transport coil member including a seat winding section connected to the transport coil section on the upstream side in the toner transport direction of the transport coil section and consisting of at least one turn, a first extension section connected to the seat winding section and extending in the direction of the rotation axis, and a second extension section extending from the first extension section in the radial direction of the transport coil section. , and the rotation drive member includes a shaft portion inserted into the seat winding portion, a hole portion into which the second extension portion is inserted, a first region adjacent to the hole portion in a width direction of the shaft portion perpendicular to the insertion direction of the second extension portion, a second region disposed on the opposite side of the hole portion from the first region, and a downstream region disposed downstream of the hole portion in the toner transport direction, and 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 seat winding portion is configured to start winding from the first extension portion toward the opposite side of the first region.

The present invention provides a toner transport device that can attach a transport coil member to a rotary drive member while reducing the risk of plastic deformation of the transport coil member when assembling the transport coil member to the rotary drive member.

Schematic cross-sectional view of an image forming apparatus. FIG. 1 is a perspective view showing a drum cartridge Cross-sectional view of drum cartridge A perspective view of a toner transport screw driving unit FIG. 13 is a diagram showing a state in which a toner transport screw and a screw driving member are connected to each other. A perspective view of a toner transport screw FIG. 11 is a perspective view of a screw driving member (second embodiment); FIG. 13 is a diagram showing a set state in a first assembly direction. FIG. 13 is a diagram showing deformation of the toner transport screw in the first assembly direction; FIG. 13 is a diagram showing a set state in a second assembly direction. FIG. 13 is a diagram showing deformation of the toner transport screw in the second assembly direction; FIG. 11 is a perspective view of a screw driving member (second embodiment); FIG. 2 is a longitudinal cross-sectional view of a second embodiment;

The following describes in detail an embodiment of the present invention with reference to the drawings. In each drawing, the same reference numerals are used to denote the same configuration or function, and duplicate explanations of these will be omitted as appropriate. In addition, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components are not intended to limit the scope of application of this technical concept to only those.

(Overall configuration and operation of 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 that employs an intermediate transfer method and is capable of forming full-color images using an electrophotographic method.

The image forming device 1 of this embodiment is equipped with image forming units that form toner images of the respective colors 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 toner used are different. Therefore, hereinafter, unless a distinction is required, the suffixes Y, M, C, and K at the end of the reference numbers indicating that the element is for one of the colors will be omitted, and the element will be generally described.

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

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 a biasing means such as a spring, and rotates in accordance with the rotation of the charging roller 13.

The image forming apparatus 1 also has an intermediate transfer belt 30 formed of an endless belt as an intermediate transfer body 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 above-mentioned primary transfer roller 31 is disposed at a position facing each photosensitive drum 12 on the inner peripheral surface side (back 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, forming a primary transfer section where the intermediate transfer belt 30 and the photosensitive drum 12 are in contact. The primary transfer roller 31 rotates in response to the rotation of the intermediate transfer belt 30. In addition, a secondary transfer roller 32, which is a roller-shaped secondary transfer member as a secondary transfer means, is disposed at a position facing the secondary transfer opposing roller 33 on the outer peripheral surface side (front side) of the intermediate transfer belt 30. The secondary transfer roller 32 is pressed against the secondary transfer opposing roller 33 via the intermediate transfer belt 30, forming a secondary transfer section where the intermediate transfer belt 30 and the secondary transfer roller 32 are in contact. In addition, a belt cleaning device 40 is disposed as an intermediate transfer body cleaning means 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 endlessly from a dielectric resin such as polyimide.

In addition, the image forming device 1 is provided with a feed roller 51 for feeding and conveying a recording material P such as recording paper, a fixing device 70 for fixing the toner image onto the recording material P, and the like.

During image formation, the surface of the photosensitive drum 12, which is rotated, is uniformly charged to a predetermined potential of a predetermined polarity by the charging roller 13. In this embodiment, a voltage is applied to the charging roller 13 from a high-voltage power source (not shown), causing a discharge on the surface of the photosensitive drum 12, thereby charging the surface of the photosensitive drum 12.

After the surface of the photosensitive drum 12 is uniformly charged, the surface of the photosensitive drum 12 is scanned and exposed by a laser scanner 22 based on the image information signal, forming an electrostatic latent image on the photosensitive drum 12. The latent image formed on the photosensitive drum 12 is developed into a toner image by the developing device 20 using toner as a developer. 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 transports it to the portion facing the photosensitive drum 12 (developing position). The developing sleeve is driven to rotate. During development, a predetermined developing voltage is applied to the developing sleeve from a high-voltage power source as a developing power source (not shown).

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 charge polarity of the toner during development, is applied to the primary transfer roller 31 from a high-voltage power source (not shown). When a full-color image is formed, the above-mentioned operation is performed in each image forming section, and the toner images of each color, Y (yellow), M (magenta), C (cyan), and K (black), formed on each photosensitive drum 12 are transferred onto the intermediate transfer belt 30 in a sequentially overlapping manner.

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

On the other hand, the recording material P is fed one by one from the paper feed cassette 50 and conveyed to the registration roller pair 60. After that, the registration 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 (secondarily transferred) to the surface of the recording material P by the action of the secondary transfer roller 32 in the secondary transfer section. When the 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 at the time of development, is applied to the secondary transfer roller 32 from a high-voltage power source (not shown). After the transfer, the small amount of residual toner remaining on the intermediate transfer belt 30 is removed and collected by the belt cleaning device 40, and is prepared for the next image formation again. The toner image transferred to the recording material P is fixed by heating and pressing by the fixing device 70, and is discharged onto the discharge tray 90 by the discharge roller pair 80.

(Drum cartridge)
Next, the configuration of the drum cartridge 10 as a photosensitive unit will be described with reference to FIGS.

The drum cartridge 10 of this embodiment comprises a photosensitive drum 12 as a photosensitive member, 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. The drum cartridge 10 of this embodiment is configured to integrally hold these together in a drum frame 11 as a frame. The drum cartridge 10 is also configured to be detachable from the image forming device main body 1 by sliding it in the longitudinal direction from the image forming device main body 1, and can be replaced for maintenance, etc.

The photosensitive drum 12 is held rotatably around the rotation axis of the drum frame 11 via a bearing (not shown). The photosensitive drum 12 is provided with a coupling 121 for receiving a driving force from a motor (not shown) as a driving source provided in the image forming apparatus main body 1 while 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 pressure 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 pressure spring (not shown). In addition, a cleaning blade 14 is fixed to the drum frame 11 as a cleaning member for cleaning the surface of the photosensitive drum 12, and is provided in contact with the surface of the photosensitive drum 12 in a counter direction to the rotation direction of the photosensitive drum 12 during image formation. In addition, a toner transport path 181 is provided near the cleaning blade 14 to collect and transport the transfer residual toner removed from the surface of the photosensitive drum 12 by the cleaning blade 14. The toner transport path 181 is provided with a toner transport screw 16 as a transport member (transport coil member) for transporting the collected toner to the outside of the drum cartridge 10. The toner transported to the outside of the drum cartridge 10 by the toner transport screw 16 is collected in a collected toner container (not shown) provided in the image forming apparatus main body 1. A gear 122 is provided at the longitudinal end of the photosensitive drum 12 as a rotating member fixed so as to rotate integrally with the photosensitive drum 12 around the rotation axis of the photosensitive drum 12. Drive transmission means 191, 192 and a screw drive member 17 as a rotation drive member are provided between the photosensitive drum 12 and the toner transport screw 16. The toner transport screw 16 is attached so as to receive drive from the screw drive member 17. The screw drive member 17 is provided with a toner seal member 182 for preventing the toner in the collected portion from entering the upstream side of the toner transport screw 16 in the toner transport direction. When the photosensitive drum 12 rotates, the rotational force of the gear 122, which rotates integrally with the photosensitive drum 12, is transmitted to the toner transport screw 16 via the drive transmission means 191, 192 and the screw drive member 17. This rotates the toner transport screw 16, and the residual toner collected in the collection section can be transported out of the drum cartridge 10.

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 rotates due to the frictional force with the photosensitive drum 12. Furthermore, when the charging roller 13 rotates, the cleaning roller 15 rotates due to the frictional force with the charging roller 13. In addition, the toner transport screw 16 rotates by receiving a driving force transmitted from the gear 122.

(First embodiment)
The first embodiment will be described with reference to Figures 5 to 11. For convenience of explanation, the toner sealing member 182 is not shown in Figures 5 and subsequent figures.

As shown in FIG. 5, the toner transport screw 16 is held by the screw drive member 17 so that the rotation axis of the screw 16 is approximately aligned with the rotation axis of the screw drive member 17.

As shown in FIG. 6, the toner transport screw 16, which serves as a transport coil member for transporting toner, has a transport coil portion 161 that transports toner in the direction of the rotation axis as it rotates. The toner transport screw 16 also has a seat winding portion 162 that is connected to the upstream end of the transport coil portion 161 of the transport coil portion in the toner transport direction. The toner transport screw 16 also has a first straight portion 163 as a first extension portion that is connected to the seat winding portion 162 and extends upstream in the toner transport direction. The toner transport screw 16 also has a second straight portion 164 as a second extension portion that is connected to the first straight portion 163 and bent at a right angle from the first straight portion toward the rotation center of the toner transport screw 16.

As shown in FIG. 7, the screw drive member 17 has a shaft portion 171 inserted into the seat winding portion 162 of the toner transport screw 16, and a hole portion 172 into which the second straight portion 164 is inserted. When the screw drive member 17 rotates, the rotation is transmitted from the inner wall of the hole portion 172 to the second straight portion 164 of the toner transport screw 16, thereby rotating the toner transport screw 16. Furthermore, the shaft portion 171 is inserted into the seat winding portion 162, so that the rotation axes of the toner transport screw 16 and the screw drive member 17 are configured to approximately coincide. In this embodiment, the hole portion 172 is a through hole and has an elongated hole shape along the rotation axis direction of the screw drive member 17. The toner transport screw 16 is urged toward the upstream side in the toner transport direction by the reaction force of the toner transport, but the more the shaft portion 171 is inserted into the seat winding portion 162, the more the shaft portion 171 is inserted into the seat winding portion 162, and the more the toner transport screw 16 is moved toward the upstream side, thereby reducing the amount of misalignment of the rotation axis of the toner transport screw 16. In addition, the end position of the hole 172 is set at a position where the shaft portion 171 is inserted into the seat turn portion 162 even when the toner transport screw 16 is positioned closest to the downstream side of the hole 172 in the transport direction. This makes it possible to hold the toner transport screw 16 so that it does not easily fall off the screw drive member 17. This makes it possible to assemble the toner transport screw 16 and the screw drive member 17 in advance and then assemble them together into the drum cartridge 10, which is advantageous in terms of ease of assembly.

As shown in FIG. 7, the screw drive member 17 has a first fitting portion 175 that is rotatably fitted and supported on the drum frame 11, and a second fitting portion 176 that is rotatably fitted and supported on a screw drive member bearing (not shown). Supported at both ends by the two fitting portions, tilting of the rotation axis of the screw drive member 17 is suppressed. Furthermore, the screw drive member 17 has a gear portion 174, and drive is transmitted from a gear 122 provided on the photosensitive drum 12 via drive transmission means 191 and 192 shown in FIG. 3.

Next, the assembly of the toner transport screw 16 and the screw drive member 17 will be described with reference to Figures 5 and 8 to 11. As described above, the toner transport screw 16 is held so that it does not easily fall off the screw drive member 17. As shown in Figure 5, in order to assemble the toner transport screw 16 to the screw drive member 17, it is necessary to deform a part of the toner transport screw 16 before assembly.

The following direction is considered as the first assembly direction. That is, as shown in FIG. 8A, the second straight portion 164 of the toner transport screw 16 is inserted into the hole 172 of the screw drive member 17 in a direction in which the rotation axis of the toner transport screw 16 and the rotation axis of the screw drive member 17 are substantially perpendicular to each other. Then, the second straight portion 164 is rotated 90° clockwise (in the direction of the arrow D1 in FIG. 8A) with respect to the screw drive member 171, as the rotation axis. In this way, the toner transport screw 16 is assembled so that the seat winding portion 162 of the toner transport screw 16 overcomes the shaft portion 171 of the screw drive member 17. At this time, the toner transport screw 16 is deformed so that the distance L1 from the point T1 where the assembly trajectory shaft portion 171 contacts the seat winding portion 162 to the second straight portion 164 is expanded by a predetermined amount L2, which is indicated by L1 in FIG. 9A. When the screw 16 is rotated in the above-mentioned direction for assembly, the force for deforming the toner transport screw 16 so that the seat winding portion 162 passes over the shaft portion 171 acts at the position T1 in the direction indicated by the arrow F1 in FIG. 9A. At this time, the point T1 is a point near 3/4 of the first turn of the seat winding portion 162. Due to the force acting at the point T1, the toner transport screw 17 is deformed so that the distance L1 is expanded by the deformation amount L2 required for assembly, and after passing over the shaft portion 171, it returns to the original length L1. FIG. 9B is a schematic diagram showing the state in which the toner transport screw 17 is deformed by the deformation amount L2 in the first assembly direction. The main deformation at this time is the deformation due to the spring property of the seat winding portion 162 in the toner transport direction from the point T1 position (FIG. 9A) to the point T2 position (FIG. 9B), that is, the deformation from the angle θ1 (FIG. 9A) of the seat winding portion 162 to θ2 (FIG. 9B). By setting the deformation amount L2 to an amount that can be deformed by the spring properties of the seat turn portion 162, it is possible to reduce the risk of plastic deformation of the toner transport screw 16.

Next, as a second assembly direction, as shown in FIG. 10(a), the toner transport screw 16 is set on the screw drive member 17 in the opposite direction to FIG. 8(a) and rotated counterclockwise (in the direction of the arrow D2 in FIG. 10(a)). At this time, the force for deforming the toner transport screw 16 so that the seat winding portion 162 overcomes the shaft portion 171 acts in the direction shown by the arrow F2 in FIG. 11(a) at a position near 1/4 of the first turn of the seat winding portion 162 shown by T3 in FIG. 11(a). This is because the shaft portion 171 contacts point T3 on the assembly trajectory. At this time, the toner transport screw 16 needs to be deformed so that the distance L3 from the second straight portion 164 to the seat winding portion 162 increases by the deformation amount L2 required for assembly, as shown in FIG. 11(b). FIG. 11(b) is a schematic diagram of the toner transport screw in the second assembly direction deformed by the deformation amount L2. In the second assembly direction, deformation is not due to the springiness of the seat turn portion 162, but is caused by tilting the second straight portion 164 and the entire seat turn portion 162 relative to the first straight portion 163, and is deformed by L2. In other words, the angle θ3 (FIG. 11A) between the first straight portion 163 and the seat turn portion 162 is deformed to θ4 (FIG. 11B). In this case, a large force is applied to the connection portion between the first straight portion 163 and the second straight portion 164, and the connection portion between the first straight portion 163 and the seat turn portion 162, and there is a risk that the toner transport screw 16 will be plastically deformed.

In this embodiment, in order to avoid plastic deformation of the toner transport screw 16 in the second assembly direction described above, a regulating portion 173 is provided on the screw drive member 17. As shown in FIG. 7, the screw drive member 17 has a first region A adjacent to the hole 172 in the width direction (radial direction of the screw drive member 17) of the shaft portion 171 perpendicular to the insertion direction of the second straight portion 164. The screw drive member 17 also has a second region B arranged on the opposite side of the first region A with respect to the hole 172, and a downstream region C arranged downstream of the hole 172 in the toner transport direction of the toner transport screw 16. In this embodiment, the regulating portion 173 is provided in the first region A, and the regulating portion 173 is not provided in the second region B and the third region C. Therefore, the height of the first region A in the insertion direction of the second straight portion 164 is configured to be higher than the second region B and the third region C.

The effect obtained by the regulating portion 173 will be described. FIG. 8(b) is a view of the state in which the toner transport screw 16 is set in the screw drive member 17 in the first assembly direction described above, and FIG. 10(b) is a view of the state in which the toner transport screw 16 is set in the screw drive member 17 in the second assembly direction described above, as viewed from the rotation axis direction (Y direction) of the screw drive member 17. Note that the X, Y, and Z directions used in the following description are as shown in FIG. 8 and FIG. 10. That is, the Y direction is the rotation axis direction of the screw drive member 17, the Z direction is the extension direction of the second straight portion 164 of the toner transport screw 16, and the second straight portion 164 is inserted into the hole portion 172 from the +Z direction toward the -Z direction. The X direction is a direction perpendicular to the Y direction and the Z direction.

In the assembled state in the first assembly direction shown in FIG. 8B, the rotation axis 16A of the toner transport screw 16 is at a position of -Z1 in the Z direction relative to the Z direction center position 171Z of the shaft portion 171 of the screw drive member 17. On the other hand, in the assembled state in the second assembly direction shown in FIG. 10B, the rotation axis 16A of the toner transport screw 16 is at a position of +Z2 in the Z direction relative to the Z center position 171Z of the shaft portion 171 of the screw drive member 17. This is because the Z direction penetration amount of the tip position of the second straight portion 164 into the hole portion 172 in the assembled state is regulated by the regulating portion 173 so that the second assembly direction is smaller than the first assembly direction by Z1+Z2. The regulating portion 173 is coaxial with the shaft portion 171 and is part of a cylindrical shape with a radius R2. The shaft portion 171 is a cross boss shape with a cylindrical shape with a radius R1 as its outer periphery, and the relationship R3>R1 is established. In addition, when the distance from the rotation axis 16A of the toner transport screw 16 to the inside of the first straight portion 163 is R3, R3 is equal to the inner radius of the seat turn portion 162, and the relationship R2>R3>R1 is established. Furthermore, when the distance in the Z direction between the apex of the regulating portion 173 and the center of the shaft portion 171 is 173Z, the relationship 173Z>R3 is established.

As shown in FIG. 11, a force acts on the seat turn portion 162 in the direction of the arrow F2 in the second assembly direction. The arrow F2 has a component in the direction in which the second straight portion 164 comes out of the hole portion 172 (the +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 out of the hole portion 172. As a result, the second straight portion 164 is configured to come out of the hole portion 172 before the toner transport screw 16 is plastically deformed, thereby releasing the assembled and set state. This makes it possible to suppress the plastic deformation of the toner transport screw 16. The restricting portion 173 shifts the tip position of the second straight portion 164 in the assembled and set state in the second assembly direction to a side that reduces the Z-direction penetration amount, thereby making it easier to release the set state than if the restricting portion 173 were not present.

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

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 arranged so as to be point symmetrical with respect to the center of the rotation axis of the screw drive member 17 in the X-Z plane. As a result, the above-mentioned effect can be obtained regardless of which side of the hole portion 172, which is a through hole, the second straight portion 164 is inserted from. However, the hole portion 172 does not have to be a through hole.

As described above, the restricting portion 173 makes it possible to avoid assembly in the second assembly direction, which has a high risk of plastic deformation of the toner transport screw 16. As a result, it is possible to reduce the risk of abnormal noise caused by friction between the toner transport screw 16 and the outer peripheral parts of the screw drive member 17 during rotational operation, which is due to plastic deformation of the toner transport screw.

(Second Example)
Next, a second embodiment will be described with reference to Figures 12 and 13. Note that the description of the same parts as those in the first embodiment will be omitted, and only the parts of the configuration that are different from the first embodiment will be described.

Figure 12 is a perspective view of the screw drive member 17 of the second embodiment, and Figure 13 is a cross-sectional view of the hole 172 in the state where the toner transport screw 16 and the screw drive member 17 of the second embodiment are assembled, as viewed from the longitudinal direction.

In the second embodiment, the screw drive member 17 does not have a gear portion 17, but has a D-cut portion 177 as a drive receiving portion, and is configured to rotate by receiving a drive force from a drive source (not shown). In addition, the hole portion 172 into which the second straight portion 164 of the toner transport screw 16 is inserted is not an elongated hole, but has a hole shape with a diameter larger than the wire diameter of the toner transport screw 16. Furthermore, the hole portion 172 is not a through hole, and the toner transport screw 16 can only be inserted into the hole portion 172 from one direction. Therefore, the effect described in the first embodiment can be obtained by providing the regulating portion 173 only in one place on the entrance side of the hole.

As described above, by providing the regulating portion 173 on the screw drive member 17, it is possible to avoid assembling the toner transport screw 16 from a direction that is at high risk of plastically deforming the toner transport screw 16 when assembling the toner transport screw 16 to the screw drive member 17. As a result, it is possible to reduce the risk of abnormal noise caused by friction between the toner transport screw 16 and the outer peripheral parts of the screw drive member 17 during rotational operation, which is due to plastic deformation of the toner transport screw 16. As a result, it is possible to provide a toner transport device that is quieter than conventional devices.

10 Drum cartridge 12 Photosensitive drum (photoconductor)
14 Cleaning blade 16 Toner transport screw 161 Transport coil portion 162 Seat turn portion 163 First straight portion 164 Second straight portion 17 Screw drive member 171 Shaft portion 172 Hole portion 173 Regulating portion 173Z Distance in Z direction of regulating portion from center of shaft portion 174 Gear portion 181 Toner transport path 191, 192 Drive transmission means R3 Radial distance from rotation axis of toner transport screw to inside of first straight portion

Claims (5)

a conveying path for conveying the toner;
a conveying coil member provided rotatably on the conveying path, the conveying coil member including a conveying coil portion formed by winding a wire in a spiral shape around a rotation axis;
a rotation drive member connected to the conveying coil member to rotate the conveying coil member,
The conveying coil member is
a coil end portion connected to the transport coil portion on an upstream side in a toner transport direction of the transport coil portion and having at least one turn;
a first extension portion connected to the seat turn portion and extending in the rotation axis direction;
A second extension portion extending from the first extension portion in a radial direction of the conveying coil portion,
The rotation drive member is
A shaft portion inserted into the end turn portion;
a hole into which the second extension portion is inserted;
a first region adjacent to the hole in a width direction of the shaft portion perpendicular to an insertion direction of the second extension portion;
A second region disposed on an opposite side of the hole from the first region;
a downstream region disposed downstream of the hole in the toner transport direction,
A toner conveying device characterized in that the height of the first region in the insertion direction is configured to be higher than those of the second region and the downstream region, and the seat winding portion is configured to start winding from the first extension portion toward the opposite side to the first region. 2 . The toner transport device according to claim 1 , wherein a height of the first region in the insertion direction with respect to a rotation center of the rotation drive member is greater than an inner radius of the seat turn portion. 3. The toner transport device according to claim 1, wherein a height of the second region and the downstream region in the insertion direction relative to a rotation center of the rotation drive member is lower than an inner radius of the seat turn portion. The toner transport device according to any one of claims 1 to 3, characterized in that the hole is a through hole, and the rotation drive member has a third region that is point-symmetrical with the first region and a fourth region that is point-symmetrical with the second region with respect to the center of the rotation axis of the rotation drive member. 5. The toner transport device according to claim 1, wherein the first region is a part of a cylindrical shape coaxial with the rotation drive member, and a radius of the cylindrical shape is larger than an inner radius of the seat turn portion.

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