Conveying member, powder conveying device, developing device and image forming apparatus

Abstract

To provide a conveying member that can prevent a reduction in stirring performance in conveying powder in an environment in which the fluidity of powder is reduced such as a high temperature and high humidity environment.SOLUTION: In a conveying member including a plurality of rows of spiral blades around a rotation shaft 180, at least one spiral blade 181 of the plurality of rows of spiral blades has a discontinuous part M that becomes discontinuous in a direction of a center line O of the rotation shaft 180. At least one spiral blade 182 of the plurality of rows of spiral blades is different in outer diameter from the other at least one spiral blade 181. The discontinuous part M is a portion where the spiral blade 181 is partially not present in the direction of the center line of the rotation shaft, and the portion may include a rib shape part 183 extending in the direction of the center line.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a conveying member, a powder conveying device, a developing device, and an image forming apparatus. [Background technology]

[0002] Conventionally, a conveying member having a plurality of helical blades arranged around a rotation axis has been known. For example, Patent Document 1 discloses a multi-thread helical blade in which, at a discontinuous portion, the upstream end and downstream end of the helical blade are out of phase with each other around the rotation axis, and the upstream end and downstream end of the helical blade facing each other across the discontinuous portion are arranged so as to overlap or coincide in the axial direction. Patent Document 2 also discloses a blade having a gap portion where the blade is discontinuous at least partially along the center line of the rotation axis. These are used to convey developer in a powder conveying device of a developing device provided in an image forming apparatus, and are said to improve the conveying and stirring performance of the developer. Summary of the Invention [Problem to be solved by the invention]

[0003] However, in any of the conveying members, there is a risk that the agitation performance may be reduced when conveying powder in an environment where the fluidity of the powder is reduced, such as a high temperature and humidity. [Means for solving the problem]

[0004] In order to solve the above-mentioned problems, the present invention provides a conveying member having a plurality of helical blades arranged around a rotation shaft, wherein at least one of the plurality of helical blades has a discontinuous portion that is discontinuous in the direction of the center line of the rotation shaft, and at least one of the plurality of helical blades has an outer diameter different from at least one of the other helical blades. The number of the plurality of threads is two, the first helical blade having a larger outer diameter has the discontinuous portion, and the second helical blade having a smaller outer diameter is continuous in the direction of the center line. It is characterized by the above. [Effects of the Invention]

[0005] According to the present invention, it is possible to suppress a decrease in stirring performance when conveying powder in an environment where the fluidity of the powder is reduced, such as a high temperature and humidity environment. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a copying machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram of a cross-sectional configuration of the process cartridge. [Figure 3] FIG. [Figure 4] FIG. 2 is a schematic diagram illustrating the structure of the developing device 4 in the longitudinal direction. [Figure 5] FIG. 2 is a schematic cross-sectional view of a mixing screw. [Figure 6] FIG. 2 is an explanatory diagram showing the configuration of the axial extension direction of the stirring screw. [Figure 7] FIG. 10 is an explanatory diagram of another example of the rib-shaped portion. [Figure 8] FIG. 10 is an explanatory diagram of yet another example of the rib-shaped portion. [Figure 9] FIG. 10 is an explanatory diagram of yet another example of the rib-shaped portion. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of an image forming apparatus equipped with a developing device employing a conveying member according to the present invention will be described below with reference to the drawings. The image forming apparatus in this embodiment is a copying machine equipped with an electrophotographic image forming unit. This copying machine is a tandem color copying machine employing an intermediate transfer method, with the image forming unit equipped with four photosensitive drums, but may be another color copying machine or a monochrome copying machine. The image forming apparatus may also be a printer without a scanner unit.

[0008] FIG. 1 is a schematic diagram showing the configuration of a copying machine according to this embodiment. The copying machine 500 according to this embodiment includes a printer unit 200 that forms an image on paper P, a recording material; a paper feed unit 300 with multiple paper feed cassettes; and a scanner unit 400 attached to the top of the printer unit 200. The printer unit 200 includes process cartridges 1Y, 1M, 1C, and 1K, which form imaging units for yellow (Y), magenta (M), cyan (C), and black (K), arranged along the rotation direction of an intermediate transfer belt 7 serving as an intermediate transfer body. Each of the process cartridges 1Y, 1M, 1C, and 1K includes a photoconductor 2 serving as a latent image carrier. Around the photoconductor 2, there are a charging device 3, optical writing devices 6Y, 6M, 6C, and 6K, a developing device 4 (only 1Y is designated by a symbol), primary transfer devices 8Y, 8M, 8C, and 8K, a photoconductor cleaning device 5, and other components.

[0009] This copying machine 500 also includes a transfer belt cleaning device 11 that cleans the intermediate transfer belt 7, and toner bottles 50Y, 50M, 50C, and 50K that contain toner to be supplied to the developing device 4.

[0010] In the printer unit 200, the color toner images formed on the photoconductors 2Y, 2M, 2C, and 2K are primarily transferred by primary transfer devices 8Y, 8M, 8C, and 8K onto the intermediate transfer belt 7, whose surface moves as shown by arrow A, so as to overlap each other, and color toner images are formed on the intermediate transfer belt 7. The color toner images on the intermediate transfer belt 7 are transported to a secondary transfer region consisting of secondary transfer devices 9a and 9b as the intermediate transfer belt 7 rotates.

[0011] The color toner image on the intermediate transfer belt 7 is secondarily transferred by secondary transfer devices 9a, 9 onto a sheet of paper P, which is transported at a predetermined timing from a paper feed unit 300 as indicated by an arrow S, in the secondary transfer region. The sheet of paper P on which the color toner image has been formed is then transported to a fixing device 12, where the color toner image is fixed onto the sheet of paper P by the action of heat and pressure. After the fixing, the sheet of paper P is discharged to a discharge unit.

[0012] Figure 2 is an explanatory diagram of the cross-sectional structure of the process cartridge 1. The only difference is the color of the developer used; the mechanism is the same for all colors, and the suffixes indicating the color of the component symbols have been omitted. The process cartridge 1 is composed of a developing device 4, photoconductor 2, charging device 3, and photoconductor cleaning device 5, with the photoconductor 2, charging device 3, and photoconductor cleaning device 5 being integrated into a photoconductor unit. The exposure device 6 shown together with the process cartridge 1 corresponds to each process cartridge and is positioned so that it can expose the entire image area on the photoconductor 2 in the longitudinal direction. The charging device 3 shown in the figure is equipped with a charging member 3a and a cleaning member 3b.

[0013] The developing device 4 is a vertical biaxial circulation type (vertical biaxial circulation type) developing device, and the developer storage section that stores the powdered two-component developer in the developing case (casing) 100 is divided into an agitation section 107 that agitates additional replenishment toner and a supply section 105 that supplies developer to the developing roller 102. The agitation section 107 and the supply section 105 are connected at both ends of the length of the developing device. The supply section 105 and the agitation section 107 are equipped with a supply screw 106 and an agitation screw 108, which are developer transport members, and circulate the developer. The illustrated supply screw 106 is a screw with three helical blades, but a screw with one or more blades may also be used. The agitation screw 108 is a transport member related to the present invention and will be described in detail later.

[0014] The developing roller 102 is composed of a developing sleeve 102a and a magnet roller 102b, and has a diameter of φ16 [mm]. The developer transported to the vicinity of the developing roller 102 in the developing unit 101 by the supply screw 106 of the supply unit 105 is attracted to the developing roller 102 by magnetic force, and after being regulated to a desired layer thickness (transport amount) by the layer thickness regulating member 103, is transported to the development area. Thereafter, the developer is returned to the developing device 4 (developing unit 101) by the developing roller 102, separated from the developing roller 102 by repulsive magnetic force, and returned to the supply unit 105 again.

[0015] The magnetic brush created by the developer being returned into the developing device 4 generates an air current that is sucked into the developing device 4 between the developing case 100. This air current prevents toner that was not used in development from scattering. At this time, the internal pressure inside the developing device 4 rises, so a pressure relief filter 104 is also provided.

[0016] Figure 3 is an explanatory perspective view of the process cartridge 1. Figure 3(a) is a view seen from the rear side in the installation direction when mounted in the copier 500, and Figure 3(b) is a view seen from the front side in the installation direction when mounted in the copier 500. The process cartridge can be removed by sliding it in the longitudinal direction from the front side of the main body of the copier 500.

[0017] As shown in Figures 3(a) and (b), in the process cartridge 1, the developing device 4, charging device 3, photosensitive member cleaning device 5, and photosensitive member 2 are fixed in desired positions by a rear side plate 204 and a front side plate 205. For example, the gap between the developing roller 102 of the developing device 4 and the photosensitive member 2 is set to 0.3 mm. The developing device 4 is driven by a driving force from a drive motor attached to the main body of the copier 500, which is input via a drive coupling 121 for drive input shown in Figure 3(a).

[0018] A drive coupling 121 provided in the developing device 4 has a gear portion, and this gear portion is connected (meshed) with a developing roller gear 122 (see FIG. 4) attached to the shaft 122a of the developing roller 102 and a supply input gear 123 attached to the shaft of the supply screw 106. Additional toner is supplied from a toner bottle 50 attached to the main body of the copier 500 to a toner supply port 127 provided in the developing device 4 shown in FIG. 3(a).

[0019] Then, as shown in FIG. 3(b), a rotational driving force is transmitted from a supply output gear 124 provided on the other end of the rotation shaft of the supply screw 106 to a mixing input gear 126 that drives the mixing screw 108 via a transmission gear 125, which is an idler gear.

[0020] 4 is a schematic diagram illustrating the longitudinal structure of the developing device 4. It is a schematic diagram of the structure as seen from the opposite side of the photosensitive member 2. The inside of the developing case 100 of the developing device 4 is divided into a supply section 105 and an agitation section 107, which are separated by a partition wall 100a, and communication sections (lifting section opening 109, dropping section opening 110) are provided near both ends of the developing device 4 in the longitudinal direction.

[0021] During image formation, it is preferable to place more developer on the supply section 105 side so that the supply of developer to the developing roller 102 is stable. For this purpose, for example, the length L1 of the lifting section opening 109, which moves from the agitation section 107 to the supply section 105, is set to 20 mm, and the length L2 of the dropping section opening 110, which moves from the supply section 105 to the agitation section 107, is set to 7 mm. This limits the flow rate. The shape of each opening is rectangular, and the length of each opening in the direction perpendicular to the paper surface is set to, for example, 10 mm. The broken lines in the figure indicate the circulation path of the developer.

[0022] In the developing device 4 described above, it is important to ensure good developer transportability and agitation. If the developer is not dispersed and agitated sufficiently, the toner will not be sufficiently charged, resulting in problems such as background smearing and toner scattering. To ensure sufficient transport power, it is effective to use a multi-start screw (a transport member with multiple helical blades around a rotating shaft). To improve dispersibility with a multi-start screw transport member using multiple helical blades, it is effective to create a flow of developer that allows it to move between the multiple transport blades.

[0023] In the devices disclosed in Patent Documents 1 and 2, discontinuous portions are provided in each transport blade in the direction of the rotation axis (the direction of the center line of the rotation axis) to create a developer flow that allows for inter-convex movement between multiple transport blades, thereby improving the dispersibility of the developer. Furthermore, in the device disclosed in Patent Document 1, the first and second helical blades are arranged so that their phases around the rotation axis differ at the discontinuous portions, thereby disrupting the developer flow and improving dispersibility. In the device disclosed in Patent Document 2, gaps are provided in the discontinuous portions, and the volume of the gaps is appropriately set to create a developer flow between each transport blade, improving dispersibility while maintaining transportability as much as possible. However, the transport components of these devices have problems with developer adhesion to the helical blades at locations where the pitch between the helical blades narrows, causing stagnation, or where the developer flow does not change at the gaps, reducing dispersibility.

[0024] In this embodiment, a structure that can solve the above problem is adopted for the mixing screw 108 of the mixing unit 107, where both conveyance and mixing performance are more strongly required. FIG. 5 is a schematic cross-sectional view of the mixing screw 108 taken along a plane perpendicular to the center line O (axis) of the rotation shaft 180. The mixing screw 108 has two helical blades with different outer diameters. The one with the larger outer diameter is the first helical blade 181, and the one with the smaller outer diameter is the second helical blade 182. An example of dimensions is as follows: The height H1 from the center line O of the first helical blade 181 is 7 mm, the height H2 from the center line O of the second helical blade 182 is 5.5 mm, and the shaft diameter of the rotation shaft 180 of the conveying screw is 5 mm. This is a two-thread screw with a lead length of 30 mm. The lead length is the length of one revolution of one helical blade in the axial extension direction.

[0025] Because the mixing screw 108 has helical blades with different outer diameters, as shown in Figure 5, when the mixing screw 108 rotates in the rotation direction B, a flow C is generated in which the agent exceeding the height H2 of the second helical blade 182 moves to the first helical blade 181. This flow C is caused by the difference in the agent volume transported by the first helical blade 181 and the second helical blade 182, and is not easily affected by agent fluidity. Therefore, it is possible to suppress a decrease in mixing performance when transporting powder in an environment where the fluidity of the powder is reduced, such as high temperature and humidity. It is preferable that the relationship between the heights H1 and H2 of two adjacent helical blades satisfy (2 / 3)H1>H2.

[0026] Furthermore, if further improvement in dispersibility is desired, it is preferable to make the angle θ2 (110° in this embodiment) between the second helical blade 182 and the axial tangent S2 an obtuse angle, larger than the angle θ1 (92° in this embodiment) between the first helical blade 181 (e.g., a non-tapered screw) and the axial tangent S1. This makes it possible to generate flow C without applying stress to the agent. With this configuration, a flow from the second helical blade 182 to the first helical blade 181 can be generated.

[0027] FIG. 6 is an explanatory diagram showing the configuration of the agitating screw 108 in the axial extension direction. FIG. 6(a) is an explanatory diagram of the external shape, and FIG. 6(b) is a development diagram of the first helical blade 181 and the second helical blade 182. The vertical axis of this development diagram is expanded circumferentially around the rotation shaft 160 and indicates the range from 0 degrees to 360 degrees, while the horizontal axis corresponds to the axial position of the rotation shaft 180 in FIG. 6(a). The solid line indicates the first helical blade 181, and the dashed line indicates the second helical blade 182. The rib-shaped portion 183, which will be described later, is shown divided into 0 degrees and 360 degrees, with the center of the plate-shaped rib-shaped portion 183 being 0 degrees = 360 degrees. In FIGS. 6(a) and 6(b), two turns of the spiral are cut out to show the details of the agitating screw 108, but this configuration is repeated continuously throughout the longitudinal direction.

[0028] In this agitating screw 108, the first helical blade 181, which has a larger outer diameter, has a discontinuous portion M where it is discontinuous in the direction of the center line of the rotation shaft, while the second helical blade 182, which has a smaller outer diameter, is continuous in the direction of the center line. In this embodiment, the discontinuous portion M is a portion where the first helical blade 181 is partially absent in the direction of the center line O of the rotation shaft 180. Specifically, the first helical blade 181 is partially cut out in the axial extension direction of the blade (a section indicated by M in the figure, for example, 15 mm), forming the discontinuous portion M. The dashed arrow F in FIG. 6(a) indicates the developer transport direction when the agitating screw 108 is rotated in the rotation direction B. The upstream rear end 181R of the cut-out first helical blade 181 is located upstream of the discontinuous portion M in the transport direction, and the downstream tip 181F of the cut-out first helical blade 181 is located downstream of the discontinuous portion M in the transport direction. Although a shape in which the first helical blade 181 is not present in the discontinuous portion M is most preferable, a sufficiently small blade can still obtain the effect, although it is inferior to the above configuration. Specifically, even if the first helical blade 181 is present, the effect can be obtained as long as the blade is smaller than the other parts of the first helical blade 181 and the second helical blade 182.

[0029] The developer that has been transported to the upstream rear end 181R of the first helical blade 181 through the discontinuous portion M where the first helical blade 181 does not exist generates a developer flow D as shown in the figure, and the developer flows into the second helical blade 182. Therefore, the developer flow C from the second helical blade 182 to the first helical blade 181 shown in FIG. 5 and the developer flow D from the first helical blade 181 to the second helical blade 182 shown in FIG. 6(b) occur continuously in the longitudinal direction of the mixing screw, thereby improving dispersibility. Moreover, of these, the flow rate of the developer flow C due to the different diameters shown in FIG. 5 is less affected by the developer fluidity as described above, which further suppresses deterioration of mixing performance when conveying powder in an environment where powder fluidity is reduced, such as at high temperature and humidity.

[0030] Furthermore, in this embodiment, as shown in Fig. 6(a), a rib-shaped portion 183 extending in the direction of the center line O is provided at the discontinuous portion M where no helical blade is present. The rib-shaped portion 183 is a convex portion that protrudes radially from the circumferential surface of the rotation shaft 180. This rib-shaped portion 183 can generate a developer flow E that continues to flow to the first helical blade 181, in addition to the developer flow D that flows to the second helical blade 182, as shown in Fig. 6(a).

[0031] If the rib-shaped portion 183 were not present, the amount of developer flowing from the first spiral blade 181 to the second spiral blade 182 due to the main developer flow D would vary depending on the fluidity of the developer, resulting in reduced mixing and transport depending on the environment. In contrast, if the rib-shaped portion 183 is provided, the developer flow can be separated into developer flow D and developer flow E by designing the specific shape of the rib-shaped portion 183, and the ratio of the separated flow rates can be set to accommodate variations in fluidity depending on the usage environment. From the perspective that the presence of the rib-shaped portion 183 reduces the amount of developer flow D by the amount of developer flow E, it can be said that the rib-shaped portion 183 regulates the amount of developer flow D that flows into the second spiral blade 182.

[0032] The main factors related to the shape of the rib-shaped portion 183 that determine the ratio of the flow rates between the developer flow D and the developer flow E are the height H3 from the center line O of the rib-shaped portion 183 and the width W of the rib-shaped portion 183 in the direction of the center line O. FIG. 6(c) is a perspective view of an example of the rib-shaped portion 183. In this example, the rib-shaped portion 183 has the shape of a flat plate or a rectangular parallelepiped with its longitudinal direction aligned with the center line O of the rotation shaft 180, and the height H3 and width W are shown. For example, the height H3 of the rib-shaped portion 183 is 6.5 mm, and the width W is 8 mm.

[0033] The ratio of the flow rates between developer flow D and developer flow E is also related to the height H1 from the center line O of first spiral blade 181, the height H2 from the center line O of second spiral blade 182, and the length M of discontinuous portion M in the direction of center line O. It is preferable that these satisfy the following relationship: Here, the symbols ">=" and "<=" indicate that the term on the left side of the symbol is greater than or equal to or less than the term on the right side. The dimensions of the specific examples described so far satisfy this relationship. H1>=H3>H2, (2 / 3)H1>H2>(1 / 2)H1, (1 / 2)M<=W <M

[0034] FIG. 7 is an explanatory diagram of another example of the rib-shaped portion 183. The rib-shaped portion 183 in this example has a tapered downstream side surface that widens from the downstream side toward the upstream side in the rotation direction when the agitating screw 108 rotates. The rib-shaped portion 183 in FIG. 7(a) is a triangle with one vertex 183a facing downstream in the rotation direction B so that the transported developer can easily split into two branches with low stress. The rib-shaped portion 183 in FIG. 7(b) is a trapezoid with parallel base sides, the downstream side in the rotation direction and the upstream side in the rotation direction are parallel to the center line O, and the left and right legs have tapered side surfaces that widen from the downstream side toward the upstream side in the rotation direction. In this example as well, the tapered shape allows the developer to be guided with low stress.

[0035] FIG. 8 is an explanatory diagram of yet another example of the rib-shaped portion 183. In this example, the position of one vertex on the downstream side of the triangle in the rotation direction of the example in FIG. 7(a) is shifted. In FIG. 8(a), the vertex is shifted to the left, and in FIG. 8(b), the vertex is shifted to the right. By shifting the position of the vertex 183a of the triangle downstream in the transport direction, the amount of developer flowing to the second spiral blade 182 can be increased. Conversely, by shifting the position upstream in the transport direction, the amount of developer flowing to the downstream tip 181F of the first spiral blade 181, which is located downstream in the transport direction from the discontinuous portion M of the first spiral blade 181, can be increased. The trapezoidal rib-shaped portion 183 in FIG. 7(b) can also have a similar effect by differentiating the tapered shapes of the left and right legs.

[0036] Furthermore, by combining a rib-shaped portion 183 in which the position of the vertex 183a of the triangle is shifted downstream in the transport direction as shown in Figure 8(a), or a rib-shaped portion 183 in which the position is shifted upstream in the transport direction as shown in Figure 8(b), it is possible to adjust the developer transport speed / developer volume / agitation state at each position on the agitating screw 108.

[0037] Figure 9 is an explanatory diagram of yet another example of the rib-shaped portion 183. In this example, the downstream tip 181F of the first spiral blade 181, which is located downstream in the conveying direction of the rib-shaped portion 183, is made narrower than the remaining width. In Figure 9, the end face 181Fa of the downstream tip 181F is hatched. This allows for smoother delivery of the material to the downstream tip 181F of the first spiral blade 181 with less stress.

[0038] In the above embodiment, the present invention is applied to a two-start screw, but it may also be applied to a three-start screw or more. In a conveying member having multiple helical blades arranged around a rotation shaft, at least one of the multiple helical blades has a discontinuous portion that is discontinuous in the direction of the center line of the rotation shaft. If at least one of the multiple helical blades has a different outer diameter from at least one other helical blade, this difference in diameter can cause powder to move to the other helical blade, as described using Figure 5. Furthermore, this movement is less affected by agent fluidity, preventing a decrease in mixing performance when conveying powder in environments where powder fluidity is reduced, such as high temperature and humidity. Furthermore, the presence of a discontinuous portion allows powder to flow through the discontinuous portion to the other helical blade, contributing to dispersibility.

[0039] 6, a discontinuous portion M is formed in the first helical blade 181 for one turn out of two turns, and this configuration is repeated continuously in the longitudinal direction, so that a discontinuous portion M is formed at a rate of one turn out of every two turns out of the first helical blade 181. The interval at which the discontinuous portions M are formed may be different from this.

[0040] In the example of Fig. 6, the discontinuous portion M is a portion where the helical blade is not present, but as described in Patent Document 1, the upstream end and downstream end of the multi-thread helical blade are out of phase with each other around the rotation axis, and the upstream end and downstream end of the helical blade facing each other across the discontinuous portion are arranged so that they overlap or coincide in the axial direction. Even in this case, it is possible to cause the powder to move to other helical blades as described using Fig. 5, and it is also possible to move the agent to other helical blades through the gap between the upstream end and downstream end located at the discontinuous portion.

[0041] Furthermore, although the above embodiments are applied to a transport member for developer, which is a powder, the present invention can also be applied to a transport member for powder other than developer, and can also be applied to a powder transport device equipped with such a powder transport member. [Explanation of symbols]

[0042] 1: Process cartridge 2: Photoreceptor 3: Charging device 3a: Charging member 3b: cleaning member 4: Developing device 5: Photoconductor cleaning device 6: Exposure equipment 7: Intermediate transfer belt 9: Secondary transfer device 9a: Secondary transfer device 11: Transfer belt cleaning device 12: Fixing device 50: Toner bottle 100: Developing case 100a: Partition wall 101: Development unit 102: Developing roller 102a: Developing sleeve 102b: Magnetic roller 103: Layer thickness control member 104: Pressure relief filter 105: Supply section 106: Supply screw 107: Stirring section 108: Mixing screw 109: Lifting opening 110: Drop opening 121: Drive coupling 122: Developing roller gear 122a: Axis 123: Supply input gear 124: Supply output gear 125: Transmission gear 126: Mixing input gear 127: Toner supply port 160: Rotation axis 180: Rotation axis 181: First spiral blade 181F: Downstream tip 181Fa: End face 181R: Upstream rear end 182: Second spiral blade 183: Rib-shaped part 183a: Vertex 200: Printer section 204: Back side version 205: Front side version 300:Paper feed section 400: Scanner section 500: Copier A: Arrow B: Rotation direction F: Arrow H1: Height H2: Height H3: Height M: Discontinuous part O: Center line P:Paper S: Arrow S1: Axis tangent S2: Axis tangent θ1 :Angle θ2 :Angle [Prior art documents] [Patent documents]

[0043] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-256429 [Patent Document 2] Japanese Patent Application Publication No. 2018-194783

Claims

1. A conveying member having a plurality of spiral blades around a rotation axis, At least one of the plurality of helical blades has a discontinuous portion that is discontinuous in the direction of the center line of the rotation shaft, At least one of the plurality of helical blades has an outer diameter different from that of at least one of the other helical blades, A conveying member characterized in that the number of threads is two, the first helical blade having the larger outer diameter has the discontinuous portion, and the second helical blade having the smaller outer diameter is continuous in the direction of the center line.

2. In the conveying member according to claim 1, The discontinuous portion is a location where the spiral blade is partially absent in the direction of the center line of the rotation shaft, and the conveying member is characterized in that the location has a rib-shaped portion extending in the direction of the center line.

3. In the conveying member according to claim 2, A conveying member characterized in that the shape of the rib-shaped portion when viewed from the radial direction of the rotating shaft is a tapered shape that widens from one end side to the other end side in the rotation direction of the rotating shaft.

4. 4. The conveying member according to claim 3, The conveying member is characterized in that the shape is a triangle having one vertex on the one end side.

5. In the conveying member according to claim 1, The discontinuous portion is a portion in the direction of the center line of the rotation shaft where the helical blade is smaller than other portions of the multiple number of threads of the helical blade, and the conveying member is characterized in that the portion has a rib-shaped portion extending in the direction of the center line.

6. A conveying member having a plurality of spiral blades around a rotation axis, At least one of the plurality of helical blades has a discontinuous portion that is discontinuous in the direction of the center line of the rotation shaft, At least one of the plurality of helical blades has an outer diameter different from that of at least one of the other helical blades, The discontinuous portion is a portion in the direction of the center line of the rotation shaft where the helical blade is smaller than other portions of the multiple number of threads of the helical blade, and the conveying member is characterized in that the portion has a rib-shaped portion extending in the direction of the center line.

7. A conveying member according to any one of claims 1 to 4, When the number of the plurality of threads is two, the angle formed by the conveying surface of the first helical blade having a larger outer diameter and the tangent to the rotation shaft is θ1, and the angle formed by the conveying surface of the second helical blade having a smaller outer diameter and the tangent to the rotation shaft is θ2, θ2>90° (obtuse angle), θ1<θ2 A conveying member characterized by satisfying the relationship:

8. A powder transport device comprising the transport member according to any one of claims 1 to 7.

9. a developer carrier; A developing case, a first conveying member provided in the developing case and configured to supply developer to the developer carrier; a second conveying member that is provided in the developing case and receives the developer from one end side of the first conveying member and transfers the developer to the first conveying member at the other end side of the first conveying member, 8. A developing device, wherein the second conveying member is the conveying member according to claim 1.

10. a developer carrier; A developing case, a first conveying member provided in the developing case and configured to supply developer to the developer carrier; a second conveying member that is provided in the developing case and receives the developer from one end side of the first conveying member and transfers the developer to the first conveying member at the other end side of the first conveying member, The second conveying member A rotor has a plurality of spiral blades arranged around a rotation axis, At least one of the plurality of spiral blades has a plurality of discontinuous portions in which the spiral blade is not present in part in the direction of the center line of the rotation shaft, A developing device characterized in that the discontinuous portion has a convex portion with a downstream side that has a tapered shape that widens from the downstream side to the upstream side in the rotation direction when the second transport member rotates to transport the developer to the other end side.

11. An image forming apparatus comprising the developing device according to claim 9 or 10.

Images