JP2019128421A - Stirring conveyance screw and developing device - Google Patents

Abstract

To provide a composition with which it is possible to raise the performance of either stirring or conveying a developer and suppress a reduction in the performance of the other.SOLUTION: A second stirring conveyance screw 158 rotates and conveys a developer in the direction of a rotation axis while stirring it. The second stirring conveyance screw 158 comprises multi-row blades 158a, 158b and a connection part 158c. Each of the multi-row blades 158a, 158b is spirally formed along the direction of the rotation axis and arranged in the radial direction with a space therebetween when seen from the direction of the rotation axis. The connection part 158c connects the multi-row blades 158a, 158b at both ends in the direction of the rotation axis of the multi-row blades 158a, 158b.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a stirring and conveying screw that conveys a developer while stirring, and a developing device including the stirring and conveying screw.

  An image forming apparatus such as an electrophotographic system includes a developing device that develops an electrostatic latent image formed on a photosensitive drum with a developer. As a developing device, a configuration using a two-component developer containing a toner and a carrier is conventionally known. Such a developing device has a stirring and conveying screw for carrying the toner and carrier while stirring the toner and the developing sleeve, and a developing sleeve for developing the electrostatic latent image with the toner. The toner is charged by being conveyed while being stirred by a stirring and conveying screw, and a developer including the charged toner is supplied to the developing sleeve.

  The stirring and conveying screw is required to convey the developer while sufficiently stirring so as to supply the sufficiently charged toner to the developing sleeve. For example, a configuration has been proposed in which a multi-spiral spiral blade is provided around the rotation shaft, and the blade is discontinuous in a part of the rotation axis direction, thereby improving the agitation of the developer (Patent Document). 1).

JP, 2010-256429, A

  However, in the case of the configuration described in Patent Document 1, the stirring property of the developer can be increased because part of the blades is discontinuous, but the transportability of the developer is reduced. When the developer transportability is lowered, it becomes difficult to sufficiently supply the developer to the developing sleeve.

  In the case of a conventional agitating and conveying screw provided with spiral blades around the rotating shaft, when trying to increase the agitating property of the developer, the conveying property of the developer is greatly reduced. In the case of trying to improve the properties, the stirring property of the developer is significantly reduced.

  An object of the present invention is to provide a configuration capable of suppressing the deterioration of the developer even if either one of the developer stirring property and the transport property is increased.

  The present invention is a stirring and conveying screw that rotates and conveys the developer in the direction of the rotation axis while stirring the developer, each of which is formed in a spiral shape along the direction of the rotation axis, and when viewed from the direction of the rotation axis A plurality of blades arranged in the radial direction through a space; and a connecting portion for connecting the plurality of blades at both ends in the rotational axis direction of the plurality of blades. It is in the stirring conveyance screw to be taken.

  The present invention is also an agitating and conveying screw that rotates and conveys the developer in the direction of the rotation axis while stirring the developer, each of which has a plurality of blades spirally formed along the direction of the rotation axis, A first connecting portion for connecting at least a pair of blades of the multi-row blades in a radial direction, and a second connecting portion for connecting the multi-row blades at both ends in the rotational axis direction of the multi-row blades; The stirring screw is characterized in that the multi-rowed vanes are arranged with spaces in the radial direction when the portion excluding the first connection portion is viewed from the rotation axis direction. is there.

  According to the present invention, even if either one of the developer agitability and transportability is raised, the other's deterioration can be suppressed.

1 is a schematic sectional view of an image forming apparatus according to a first embodiment. FIG. 1 is a schematic sectional view of a developing device according to a first embodiment. The schematic plan view which abbreviate | omitted a part of FIG. 2 and was seen from upper direction. The (a) partial side view of the stirring conveyance screw which concerns on 1st Embodiment, (b) Partial perspective view. The schematic diagram for demonstrating the conveyance property of the developer by the stirring conveyance screw which concerns on 1st Embodiment. The graph which shows the relationship between the conveyance speed of the stirring conveyance screw which concerns on a comparative example, and a stirring rate. It is a schematic diagram for explaining the stirring characteristics of the stirring and conveying screw, (a) initial state, (b) state 1, (c) state 2, (d) state 3, (e) standard of each state The figure which shows the relationship of a deviation and the stirring rate, respectively. The side view which shows the stirring conveyance screw of a comparative example. The (a) partial side view of the stirring conveyance screw which concerns on 2nd Embodiment, (b) Partial perspective view. The graph which shows the relationship between the conveyance speed at the time of making the paddle space | interval of the stirring conveyance screw which concerns on 2nd Embodiment differ, and a stirring rate. The graph which shows the relationship between the conveyance speed at the time of making the paddle width of the stirring conveyance screw which concerns on 2nd Embodiment differ, and a stirring rate. The graph which shows the relationship between the conveyance speed at the time of varying the hollow diameter of the stirring conveyance screw which concerns on 2nd Embodiment, and a stirring rate. (A) Partial side view of the stirring conveyance screw shown as a comparison for demonstrating the structure of the stirring conveyance screw which concerns on another example of 2nd Embodiment, (b) Partially enlarged view. (A) Partial side view of the stirring conveyance screw which concerns on another example of 2nd Embodiment, (b) A partial perspective view. (A) A partial perspective view of a stirring conveyance screw concerning a 1st example of a 3rd embodiment, (b) A partial perspective view of a stirring conveyance screw concerning a 2nd example, (c) 2nd stirring concerning a 2nd example The enlarged top view which looked at a part of conveyance screw from the radial direction. The graph which shows the relationship between the conveyance speed at the time of making the paddle inclination angle (theta) of the stirring conveyance screw which concerns on the 2nd example of 3rd Embodiment differ, and a stirring rate.

First Embodiment
The first embodiment will be described using FIGS. 1 to 8. First, a schematic configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG.

[Image forming apparatus]
The image forming apparatus 1 of the present embodiment is a full-color multifunction peripheral, and is placed on the image forming apparatus main body 100, an image reading unit 200 disposed above the image forming apparatus main body 100, and the image reading unit 200. And an original conveying unit 300. The image forming apparatus main body 100 according to the present embodiment has an electrophotographic tandem configuration including four image forming units 11Y, 11M, 11C, and 11K each having a photosensitive drum 12 as an image carrier.

  The image forming apparatus main body 100 forms a toner image (image) on a recording material in accordance with an image signal from a host device such as a personal computer that is communicably connected to the image reading unit 200 or the image forming apparatus main body 100. Examples of the recording material include sheet materials such as paper, plastic film and cloth. The image forming units 11Y, 11M, 11C, and 11K form yellow, magenta, cyan, and black toner images, respectively.

  The four image forming units 11Y, 11M, 11C, and 11K included in the image forming apparatus main body 100 have substantially the same configuration except that the development colors are different. Therefore, the image forming unit 11Y will be described as a representative, and description of the other image forming units will be omitted.

  In the image forming unit 11Y, a cylindrical photosensitive member, that is, a photosensitive drum 12 is disposed as an image bearing member. The photosensitive drum 12 is rotationally driven in the direction of the arrow in the drawing. Around the photosensitive drum 12, a charging roller 13 as a charging unit, a developing device 15, a primary transfer roller 16 as a transfer unit, and a cleaning unit 18 as a cleaning unit are arranged. An exposure device (laser scanner in this embodiment) 14 as an exposure unit is disposed below the photosensitive drum 12 in the drawing.

  An intermediate transfer belt 17 is disposed above FIG. 1 of each image forming unit. The intermediate transfer belt 17 as an intermediate transfer member is an endless belt, and is configured to be stretched around a plurality of rollers and to move around (rotate). The intermediate transfer belt 17 carries and conveys the toner image primarily transferred to the intermediate transfer belt 17 as will be described later. A secondary transfer outer roller 22 as a secondary transfer unit is disposed at a position facing the secondary transfer inner roller 21 among the rollers for stretching the intermediate transfer belt 17 with the intermediate transfer belt 17 interposed therebetween. The secondary transfer portion T2 is configured to transfer the toner image on the belt 17 to the recording material. A fixing device 24 is disposed downstream of the secondary transfer portion T2 in the recording material conveyance direction.

  Below the image forming apparatus main body 100, a cassette 19 containing a recording material S is disposed. The recording material S fed from the cassette 19 is conveyed toward the registration roller 20. Then, the leading end of the recording material S abuts against the registration roller 20 in the stopped state, and a loop is formed to correct the skew of the recording material S. Thereafter, the registration roller 20 is started to rotate in synchronization with the toner image on the intermediate transfer belt 17, and the recording material S is conveyed to the secondary transfer portion T2.

  A process of forming, for example, a full color image of four colors by the image forming apparatus main body 100 configured as described above will be described. First, when the image forming operation starts, the surface of the rotating photosensitive drum 12 is uniformly charged by the charging roller 13. Next, the photosensitive drum 12 is exposed by a laser beam corresponding to the image signal emitted from the exposure device 14. Thereby, an electrostatic latent image corresponding to the image signal is formed on the photosensitive drum 12. The electrostatic latent image on the photosensitive drum 12 is visualized by a toner as a developer accommodated in the developing device 15 and becomes a visible image.

  The toner image formed on the photosensitive drum 12 is primarily transferred to the intermediate transfer belt 17 at the primary transfer portion T1 configured with the primary transfer roller 16 disposed with the intermediate transfer belt 17 interposed therebetween. At this time, a primary transfer bias is applied to the primary transfer roller 16. The toner remaining on the surface of the photosensitive drum 12 after the primary transfer (transfer residual toner) is removed by the cleaning device 18.

  Such an operation is sequentially performed in each of the yellow, magenta, cyan, and black image forming units, and the four color toner images are superimposed on the intermediate transfer belt 17. Thereafter, the recording material S accommodated in the cassette 19 is conveyed to the secondary transfer portion T2 in accordance with the toner image formation timing. Then, by applying a secondary transfer bias to the secondary transfer outer roller 22, the four color toner images on the intermediate transfer belt 17 are secondarily transferred onto the recording material S at once. The toner remaining on the intermediate transfer belt 17 without being completely transferred at the secondary transfer portion T 2 is removed by the intermediate transfer belt cleaner 23.

  Next, the recording material S is conveyed to a fixing device 24 as a fixing unit. The fixing device 24 internally includes a fixing roller 24a and a pressure roller 24b having a heat source such as a halogen heater, and the fixing roller 24a and the pressure roller 24b form a fixing nip portion. The recording material S is heated and pressurized by passing the recording material S on which the toner image is transferred to the fixing nip portion of the fixing device 24. The toner on the recording material S is melted and mixed to be fixed on the recording material S as a full-color image. Thereafter, the recording material S is discharged onto the discharge tray 27 by the discharge roller 25. This completes the series of image forming processes.

  Note that the image forming apparatus main body 100 according to the present embodiment forms a single-color or multi-color image using an image forming unit for a desired single color or some of four colors, such as a black single-color image. It is also possible.

  Further, above the intermediate transfer belt 17 of the image forming apparatus main body 100, a toner cartridge 26 containing a developer of each color is disposed. Each color toner cartridge 26 replenishes the corresponding developing device 15 with a replenishment developer.

[Developer]
Next, the developing device 15 of the present embodiment will be described with reference to FIGS. 2 and 3. In the present embodiment, as described above, the configurations of the yellow, magenta, cyan, and black developing devices are the same in all. The developing device 15 includes a developing container 151 that contains a two-component developer (hereinafter referred to as a developer) containing non-magnetic toner particles (toner) and magnetic carrier particles (carrier) as main components.

  The toner has colored resin particles including a binder resin, a coloring agent, and, if necessary, other additives, and colored particles to which external additives such as colloidal silica fine powder are externally added. . As the carrier, for example, surface oxidized or unoxidized iron, metals such as nickel, cobalt, manganese, chromium, rare earths and the like, alloys thereof, oxide ferrites and the like can be suitably used. Resin coated carriers are also applicable. The method for producing these magnetic particles is not particularly limited.

  The inside of the developing container 151 is divided into a developing chamber 153a as a first chamber and a stirring chamber 153b as a second chamber by a partition wall 155 extending in the vertical direction. The developing chamber 153a and the stirring chamber 153b include Each contains a developer. A first stirring and conveying screw 157 and a second stirring and conveying screw 158 are disposed in the developing chamber 153a and the stirring chamber 153b, respectively.

  The first stirring and conveying screw 157 rotates and conveys the developer in the developing chamber 153a (the first chamber) in the rotational axis direction (the direction of the arrow α in FIG. 3) while agitating the developer. On the other hand, the second agitating / conveying screw 158 rotates and agitates the developer in the agitating chamber 153b (second chamber), while rotating in the rotation axis direction and in the direction opposite to the first agitating / conveying screw 157 (FIG. 3). Transport in the direction of arrow.

  The first stirring and conveying screw 157 has a spiral blade 157 b around the rotation shaft 157 a. The first stirring and conveying screw 157 disposed in the developing chamber 153 a is a supply auger having a function of supplying the developer to the developing sleeve 152 in addition to the function of stirring and mixing the developer. On the other hand, the second stirring and conveying screw 158 is an ad mix auger mainly aiming to stir and mix the supplied toner with the existing two-component developer in the stirring chamber 153 b.

  That is, a replenishment port 159 for replenishing a replenishment developer from the toner cartridge 26 (FIG. 1) via a replenishing device (not shown) is provided upstream of the second agitating and conveying screw 158 in the agitating chamber 153b. It is formed. Then, the toner supplied to the stirring chamber 153b from the supply port 159 and the developer already in the stirring chamber 153b are stirred and conveyed by the second stirring and conveying screw 158 to make the toner concentration uniform. The details of the second stirring and conveying screw 158 will be described later.

  Further, a toner concentration sensor 160 is disposed on the downstream side of the second stirring conveyance screw 158 in the conveyance direction of the stirring chamber 153 b. The toner concentration sensor 160 detects the toner concentration (the ratio of the weight of the toner to the total weight of the carrier and the toner, the T / D ratio) in the stirring chamber 153b. Then, based on the detection result of the toner concentration sensor 160, when the toner concentration of the developer in the developing container 151 is lower than a predetermined range by development, new development is performed in the stirring chamber 153b through the replenishment port 159. Agent is supplied.

  The partition wall 155 has a communication port that allows the developing chamber 153a and the stirring chamber 153b to communicate with each other at the end portions in the left-right direction in FIG. 3 (upstream and downstream ends in the transport direction of the first and second stirring transport screws). 156a and 156b are respectively formed. The developer is circulated between the developing chamber 153 a and the stirring chamber 153 b by the conveyance force of the first and second stirring and conveying screws 157 and 158. That is, the developing chamber 153a and the stirring chamber 153b form a developer circulation path. As a result, the developer in the developing chamber 153a, in which the toner is consumed due to the development and the toner density is lowered, moves into the stirring chamber 153b, and is stirred and conveyed together with the toner replenished in the stirring chamber 153b. The agent moves into the developing chamber 153a.

  The developing container 151 is opened at a position facing the photosensitive drum 12 (FIG. 1), and the developing sleeve 152 as a developer carrier is rotatably disposed so as to be partially exposed in the opening. Yes. The developing sleeve 152 is formed into a cylindrical shape by, for example, an aluminum alloy, and rotates in the direction indicated by the arrow during the developing operation. Further, a magnet roll as a magnetic field generating means is fixedly disposed inside the developing sleeve 152, and the developing sleeve 152 carries and conveys the developer on the surface by the magnetic field of the magnet roll. Further, a regulating blade 154 as a developer regulating member is disposed around the developing sleeve 152 so that the tip thereof is in close proximity to a part of the surface of the developing sleeve 152.

  The regulating blade 154 is a member formed to extend in the rotational axis direction of the developing sleeve 152, and regulates the amount (layer thickness) of the developer carried and conveyed by the developing sleeve 152. The developer whose layer thickness is regulated by the regulating blade 154 is conveyed to the developing area facing the photosensitive drum 12 while being carried on the developing sleeve 152.

  The developing device 15 configured as above charges and transports the developer by the first and second stirring and conveying screws 157 and 158, thereby charging the toner and the carrier, respectively. Then, the developer in the developing chamber 153 a is carried on the developing sleeve 152, and is conveyed by the rotation of the developing sleeve 152. Next, the amount (layer thickness) of the developer is made appropriate by the regulation blade 154.

  The developer whose layer thickness is regulated is conveyed by the developing sleeve 152 to the developing area. Here, by applying a developing bias in which a direct current and an alternating electric field are superimposed on the developing sleeve 152, the toner on the developing sleeve 152 is moved to the electrostatic latent image side of the photosensitive drum 12, and the electrostatic latent image The toner image is developed as a toner image. The developer whose development has been completed is taken into the developing chamber 153. In addition, the developer is appropriately supplied from the stirring chamber 153 b to the developing chamber 153 a according to the consumption of the developer in such a developing operation, and the continuous operation of the developing device 15 is enabled.

  Here, it is desired to increase the productivity of the image forming apparatus. For this reason, if the process speed, ie, the speed for forming a toner image is increased to increase the number of output sheets per unit time of the image forming apparatus, the rotational speed of the photosensitive drum 12 is also increased. It is also required to increase the driving speed of 15. For this reason, it is also required to increase the transport speed of the developer in the developing device.

  At this time, in the case of the stirring and conveying screw in which the spiral blade is provided around the rotation shaft as in the prior art, if the conveying speed of the developer is increased, the stirring property of the developer is lowered. If the stirring property of the developer is lowered, it becomes difficult to sufficiently charge the toner, which affects the image. For this reason, in the present embodiment, by setting the second stirring and conveying screw 158 as follows, the conveying speed of the developer can be increased while suppressing the deterioration of the stirring property of the developer.

[Second stirring and conveying screw]
Next, the configuration of the second stirring and conveying screw 158 (admix auger) of the present embodiment will be described using FIGS. 4 (a) and 4 (b). The second stirring and conveying screw 158 has a plurality of multi-blades 158 a and 158 b and a connecting portion 158 c. Each of the multi-blade blades 158a and 158b is formed in a spiral shape along the rotation axis direction, and when viewed from the rotation axis direction, is arranged in a radial direction with a space therebetween. That is, the radially inner side of the blades 158a and 158b is hollow. In other words, like the first stirring and conveying screw 157, the second stirring and conveying screw 158 has a shape in which the rotating shaft is omitted when the spiral blades 158a and 158b are temporarily provided around the rotation shaft. Yes. In this embodiment, although it is set as 2 blade | wings 158a, 158b, the number of blade | wings should just be two or more, such as 3, 4 articles | strands other than two.

  The connecting portion 158 c connects the two blades 158 a and 158 b at both axial ends of the two blades 158 a and 158 b. In the present embodiment, the connecting portion 158c is a pair of disk-shaped members, and both ends of the blades 158a and 158b are fixed to the disk-shaped members, so that both ends of the blades 158a and 158b are fixed. Connected to each other. In other words, the blades 158a and 158b are disposed between the pair of connecting portions 158c, and both end portions of the blades 158a and 158b are connected to the connecting portion 158c. The blades 158a and 158b are thus connected to the connecting portion 158c at both ends in the rotational axis direction, so that the mutual positional relationship is maintained.

  The pair of connection parts 158c have cylindrical shaft parts 158d that project on the opposite side to the blades 158a and 158b, respectively. The central axis of each shaft portion 158 d is made to coincide with the rotation axis of the second stirring and conveying screw 158. As shown in FIG. 3, the pair of shaft portions 158d is rotatably supported with respect to the developing container 151 via a bearing. As a result, the second agitating / conveying screw 158 is rotatably supported with respect to the developing container 151 and is driven to rotate together with the first agitating / conveying screw 157 and the developing sleeve 152 by driving a motor (not shown) connected to the shaft portion 158d. Is done.

  In such a second agitating and conveying screw 158, for example, blades 158a and 158b and a pair of connecting portions 156c are integrally formed of resin or the like. For example, molding is performed using a mold divided into two.

  Further, the advancing directions of the blades 158a and 158b accompanying the rotation of the second stirring and conveying screw 158 are formed to be the same as each other. That is, when the second stirring and conveying screw 158 rotates, the direction in which the blade 158a conveys the developer along the rotation axis direction and the direction in which the blade 158b conveys the developer along the rotation axis direction are made to coincide with each other. ing.

  Further, the two blades 158a and 158b are arranged at equal intervals in the rotation direction. In other words, in the present embodiment, the two blades 158a and 158b are arranged so that the phases in the rotational direction are different by 180 °. The two wings 158a and 158b may not be arranged at equal intervals in the rotation direction. However, when the 2nd stirring conveyance screw 158 is fabricated using the metallic mold divided into two as mentioned above, it is preferred to arrange two blades 158a and 158b at equal intervals in the rotation direction. Further, if the mold can be divided into two and the molded product can be taken out, the distance between the two blades 158a and 158b in the rotational direction may be slightly shifted.

  The two blades 158a and 158b are arranged at the same pitch. That is, the amount of advance (pitch P) per rotation of the blade 158a is the same as the amount of advance per rotation of the blade 158b. The pitch of the two blades 158a and 158b may be different from each other. In this case, it is preferable to set the pitch of the other blade to an integral multiple such as 2 times the pitch of the one blade.

  Furthermore, the two blades 158a and 158b preferably have an inner diameter d2 of 28 to 58% of the outer diameter D1 when viewed in the rotation axis direction. In the present embodiment, the blades 158a and 158b have the same shape, and have an outer diameter D1 of 14 mm, an inner diameter d2 of 6 mm, and a pitch P of 30 mm. The inner and outer diameters of the blades 158a and 158b may not be identical to each other.

[Transport capacity]
Next, the conveyance capability of the second agitation conveyance screw 158 will be described with reference to FIG. As shown in FIG. 5, the second stirring and conveying screw 158 first causes the developer in the stirring chamber 153b to generate a conveying force shown by A in the figure by the rotating blades 158a and 158b. Here, the space indicated by the arrow B in the figure is the inner diameter d2 portion of the blade 158a and the blade 158b, and the developer in this space does not come in contact with the blades 158a and 158b. No force is generated.

  However, since the developer in the space indicated by arrow B is surrounded by the developer being conveyed as indicated by arrow A, it cannot remain at the same location, and as a result, is conveyed in the same direction as arrow A. Is done. That is, the second agitating and conveying screw 158 has a space on the inner side in the radial direction of the blades 158a and 158b, and therefore has a higher conveying force than the conventional configuration in which the spiral blades are provided on the rotation shaft.

[Experiment that investigated transport speed and agitation rate]
Here, when the 2nd stirring conveyance screw 158 of this embodiment is used (Example 1), and the case where the stirring conveyance screw which provided the helical blade | wing on the rotating shaft is used (Comparative Examples 1-3). The experimental results of examining the transport speed and the stirring rate of the developer are shown in FIG. In the experiment, the example 1 and the comparative examples 1 to 3 were disposed in the stirring chamber of the developing device shown in FIGS. 2 and 3, and the transport speed and the stirring rate in each case were examined.

  In the experiment, the initial state was the timing at which the new developer replenished into the stirring chamber 153b through the replenishing port 159 and the developer refluxed from the developing chamber 153a into the stirring chamber 153b merged. And the vertical axis | shaft of FIG. 6 has shown the stirring rate after rotating the stirring conveyance screw of each example arrange | positioned in the stirring chamber 153b a specified number of times from the initial state. On the other hand, the horizontal axis in FIG. 6 indicates the transport speed of the developer transported by the stirring transport screw of each example arranged in the stirring chamber 153b after the merging of the developers.

  Here, the stirring rate will be described with reference to the conceptual diagrams of FIGS. In FIGS. 7A to 7D, the stirring state of the developer in the stirring chamber 153b is divided into blocks in the rotation direction of the stirring and conveying screw to be easily understood visually.

  7A to 7D, the left side is the first space 153b1 of the stirring chamber 153b and the right side is the second space 153b2 with the center (vertical line) of the rotation axis E of the stirring and conveying screw as a boundary. In addition, although the 2nd stirring conveyance screw 158 of Example 1 does not have a rotating shaft, it assumes that the hollow part inside the radial direction of blade | wing 158a, 158b is a rotating shaft. Further, it is assumed that developers C and D having different properties are accommodated in the stirring chamber 153b. In this case, FIG. 7A shows an initial state in which the developer C is stored in the first space 153b1 and the developer D is stored in the second space 153b2.

  Next, the content ratio of the developer occupied in the first space 153 b 1 and the second space 153 b 2 is measured. For example, when focusing on the developer C, in FIG. 7A, the content ratio of the developer C in the first space 153b1 is 1, and the content ratio of the developer C in the second space 153b2 is 0. Become.

  Furthermore, σ = 0.71 can be obtained by calculating the standard deviation of the content ratio described above. In this initial state, the stirring rate is defined as 0 [%] from the meaning of the separated states of the developers C and D.

  On the other hand, in FIG. 7D, the developer C and the developer D are stored in the same amount in the first space 153 b 1 and the second space 153 b 2 with the center (vertical line) of the rotation axis E as a boundary. Shows the third state. When the content ratio of the developer occupying the first space 153b1 and the second space 153b2 is measured in the state 3 as in the initial state, the content ratio of the developer C occupying the first space 153b1 and the second The content ratio of the developer C occupying the space 153b2 is 0.5.

  From this, σ = 0 can be obtained by calculating the standard deviation of the content ratio of state 3. In this state 3, the stirring rate is defined as 100 [%] from the meaning of the state where the developer is uniformly mixed.

  State 1 in FIG. 7 (b) and state 2 in FIG. 7 (c) show an example in which the stirring rate is in the state between the initial state in FIG. 7 (a) and state 3 in FIG. 7 (d). Yes. Specifically, FIG. 7B can be quantified with a stirring rate of 33.3 [%], and FIG. 7C can be quantified with a stirring rate of 66.7 [%]. A table summarizing these relationships is shown in FIG. 7 (e).

  Next, the structure of the stirring conveyance screw of Comparative Examples 1-3 is demonstrated using FIG. The stirring and conveying screw 180 of Comparative Example 1 is provided with two spiral blades 182 and 183 around the rotating shaft 181. In other words, the rotary shaft 181 is provided on the radially inner hollow portion of the blades 158a and 158b of the second stirring and conveying screw 158 of the first embodiment to make it solid.

  The stirring and conveying screw 180a of Comparative Example 2 is provided with a rib 184a on the rotating shaft 181 in the portion between the blades 182 and 183 of the stirring and conveying screw 180 of Comparative Example 1, and the stirring property is improved from that of Comparative Example 1. It is. The agitating and conveying screw 180b of Comparative Example 3 is such that the width of the rotating shaft 181 of the rib 184b in the rotation axis direction is larger than that of the rib 184a of Comparative Example 2 and the stirring property is further improved compared to Comparative Example 2. .

  As apparent from FIG. 6, in the case of the configurations of Comparative Examples 1 to 3, the stirring property is obtained by adding the ribs 184 a and 184 b to the stirring and conveying screw 180 of Comparative Example 1 as in Comparative Examples 2 and 3. Improved, but the transport speed decreased. From this, it can be seen that the stirring rate and the transport speed are in a trade-off relationship.

  On the other hand, in the case of the second stirring and conveying screw 158 of Example 1, the conveying speed can be increased while maintaining the stirring property relative to Comparative Example 1. This is because the developer can be transported in the space shown in B of FIG. 5 by making the space occupied by the rotating shaft 181 hollow by the stirring and transporting screw 180 of Comparative Example 1. As a result, in the case of Example 1, as compared with Comparative Example 1, the transport performance could be improved by about 11.3% while maintaining the stirring performance.

  In the case of this embodiment, the conveyance speed of the first agitation conveyance screw 157 arranged in the developing chamber 153a is also made faster than the conventional one because the conveyance speed of the second agitation conveyance screw 158 arranged in the agitation chamber 153b is improved. ing. In the present embodiment, the first stirring and conveying screw 157 has a configuration in which a spiral blade 157 b is provided around the rotation shaft 157 a as in a conventional screw. For this reason, when the conveyance speed is increased, the stirring property is lowered. However, since the developer is sufficiently stirred by the second stirring and conveying screw 158 in the stirring chamber 153b, there is no problem even if the stirring performance is somewhat reduced in the developing chamber 153a. However, in order to maintain the stirring performance in the developing chamber 153a, the first stirring and conveying screw disposed in the developing chamber 153a may have the same configuration as the second stirring and conveying screw 158.

  As described above, in the case of the present embodiment, even if one of the agitating property and the conveying property of the developer is increased, the other decrease can be suppressed. In the case of the second stirring and conveying screw 158 of the present embodiment in particular, the conveyance can be improved while maintaining the stirring property. For this reason, even if the driving speed of the developing device 15 is increased to increase the productivity of the image forming apparatus, the developer can be sufficiently stirred, and the image forming apparatus can be produced while suppressing the deterioration of the image quality of the output image. Can be enhanced.

Second Embodiment
The second embodiment will be described using FIGS. 9 to 14 with reference to FIGS. 1 to 3. The second stirring and conveying screw 168 of this embodiment is obtained by adding a paddle 170 to the configuration of the second stirring and conveying screw 158 of the first embodiment described above. Since other configurations and operations are the same as those of the first embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and illustration and description thereof are omitted or simplified. The differences from the first embodiment will be mainly described.

  In the case of the configuration of the first embodiment, in order to improve the productivity of the image forming apparatus, the conveying speed is increased while maintaining the stirring property of the second stirring and conveying screw 158. On the other hand, for example, in order to miniaturize the developing device, it may be desired to shorten the dimension in the longitudinal direction of the developing device (the rotational axis direction of the second stirring and conveying screw). In this case, the length of the path for stirring and conveying the developer in the developing device becomes short, so that the stirring can not be performed enough to impart a sufficient charge amount to the toner in this path unless the stirring property is increased. There is sex.

  Therefore, in such a case, it is required to improve the stirring property even if the transport speed of the developer is somewhat reduced. However, if the transport speed is reduced too much in order to increase the stirring property, the productivity is significantly reduced, which is not preferable. Therefore, in the present embodiment, the stirring property is improved while suppressing the deterioration of the transportability of the developer.

  As shown in FIGS. 9A and 9B, the second stirring and conveying screw 168 disposed in the stirring chamber 153b (see FIG. 2) of the present embodiment has a plurality of blades 168a and 168b and a first connection. It has the paddle 170 as a part, and the connection part 158c as a 2nd connection part. The multi-blade blades 168a and 168b are each formed in a spiral shape along the rotation axis direction in the same manner as the blades 158a and 158b of the first embodiment, and the portion excluding the paddle 170 is viewed from the rotation axis direction. In the radial direction, they are spaced apart from one another. That is, the inner side in the radial direction of the blades 168a and 168b excluding the paddle 170 is hollow. In this embodiment, although it is set as 2 blade | wings 168a and 168b, the number of blade | wings should just be two or more, such as 3 and 4 articles | strands other than two.

  In addition, the two blades 168a and 168b are arranged at equal intervals in the rotational direction as in the first embodiment. In other words, in the present embodiment, the two blades 168a and 168b are arranged so that the phases in the rotational direction are different by 180 °. In the present embodiment as well, the two blades 168a and 168b do not have to be arranged at equal intervals in the rotation direction. Further, as in the first embodiment, the advancing directions of the blades 168 a and 168 b accompanying the rotation of the second stirring and conveying screw 168 are formed to be the same as each other.

  As in the first embodiment, the connecting portion 158c connects the two blades 168a and 168b at both axial ends of the two blades 168a and 168b, and the positional relationship between the blades 168a and 168b is determined. Hold. Further, the pair of connecting portions 158c have cylindrical shaft portions 158d that protrude to the opposite sides of the blades 168a and 168b, respectively, as in the first embodiment, and the pair of shaft portions 158d are connected to the developing container 151. On the other hand, it is rotatably supported via a bearing (see FIG. 3).

  The paddle 170 connects at least a pair of blades 168a and 168b among the multiple blades in the radial direction. In the present embodiment, since the number of blades is two, the blades 168a and 168b are respectively disposed by a plurality of paddles 170 arranged in directions perpendicular to the rotation axis direction of the second agitating and conveying screw 168 except for both ends in the rotation axis direction. It is connected. The pair of blades 168a and 168b connected by the paddle 170 are arranged at the same pitch. That is, the amount of advance (pitch P) per rotation of the blade 168a is the same as the amount of advance per rotation of the blade 168b.

  The paddle 170 is formed in a plate shape, and the length (width) H in the rotation axis direction is 5 to 15% of the pitch of the pair of blades 168a and 168b. Further, the paddle 170 is disposed so that the surface of the plate is substantially parallel to the rotation axis direction. Furthermore, a plurality of paddles 170 are arranged at equal intervals in the rotation axis direction. If the arrangement | positioning space | interval of the paddle 170 is described with the advancing angle of the blade | wing 168a, in this embodiment, the some paddle 170 will be arrange | positioned every 180 degrees (every half pitch). The advance angle of the blade 168a is the amount of advance in the direction of the rotation axis of the blade relative to the rotation angle of the blade. For example, when the blade 168a is disposed every rotation of the blade 168a, the paddle 170 is rotated every 360 ° (every pitch). It will be arranged.

  Also in the case of the present embodiment, it is preferable that the inner diameter d2 of each of the two blades 168a and 168b be 28 to 58% of the outer diameter D1 when viewed in the rotation axis direction. In the present embodiment, the blades 168a and 168b have the same shape, and the outer diameter D1 is 14 mm, the inner diameter d2 is 6 mm, and the pitch P is 30 mm. Further, the width H of the paddle 170 is 4 mm.

[Experiment that investigated transport speed and agitation rate]
Here, in the case where the second stirring and conveying screw 168 of this embodiment is used (Examples 2 to 4), and in Example 1 and Comparative Examples 1 to 3 described in the first embodiment, the developer is conveyed. The experimental results of examining the speed and stirring rate are shown in FIGS. In the experiment, Examples 1 to 4 and Comparative Examples 1 to 3 were placed in the stirring chamber of the developing device shown in FIGS. 2 and 3, and the conveyance speed and stirring rate in each case were examined. The experimental method is the same as the case where Example 1 and Comparative Examples 1 to 3 are described in the first embodiment.

  First, FIG. 10 is a graph of the relationship between the conveying speed and the stirring rate when the arrangement interval (paddle interval) of the paddles 170 of the second stirring and conveying screw 168 according to the second embodiment is changed. In Example 2, the paddle spacing is indicated by the above-described lead angle, and experiments were performed with the paddle spacing varied in the range of 120 ° to 540 °.

  As can be seen from FIG. 10, in comparison with Example 1 without paddle 170, in Example 2 with paddle 170, the agitation was improved but the conveyance speed was reduced regardless of the paddle interval. In the case of Example 2, when the paddle interval was narrow, the agitation was improved while the conveyance speed was lowered. Conversely, when the paddle interval was wide, the agitation was reduced while the conveyance speed was improved. In addition, when the paddle interval is 120 ° compared with the case without paddle, the variation width corresponds to about 14% of the stirring rate and about 25% of the conveying speed. That is, it was found that the stirring rate and the conveyance speed can be controlled by adding the paddle 170 to the shape of Example 1 and adjusting the paddle interval.

  Moreover, in the case of Example 2, compared with Comparative Examples 1-3, the fall of the conveyance speed was suppressed, raising the stirring rate to the comparative examples 2 and 3 or more.

  Next, FIG. 11 is a graph of the relationship between the conveying speed and the stirring rate when the width (paddle width) of the paddle 170 of the second stirring and conveying screw 168 according to the third embodiment is changed. In Example 3, when the paddle interval was 180 ° and 360 °, the experiment was conducted in the case where the paddle width H was 4 mm and 2 mm, respectively.

  As is clear from FIG. 11, compared with Example 1 without the paddle 170, in Example 3 with the paddle 170, although the paddle width H, the agitation was improved, but the conveyance speed was reduced. In the case of Example 3, when the paddle width H is wide (paddle width 4 mm in the figure), the agitation improves, while the conveying speed decreases, and conversely, the paddle width H is narrow (paddle width 2 mm in the figure). The transport speed was improved while the property was reduced. In other words, it was found that the stirring rate and the conveyance speed can be controlled by adding the paddle 170 to the shape of Example 1 and adjusting the paddle width H. In addition, it has been found that the paddle width H of about 5% to 15% of the pitch P of the blade 168a is suitable for increasing the stirring rate while suppressing the decrease in the transfer speed.

  Next, FIG. 12 is a graph of the relationship between the conveyance speed and the stirring rate when the inner diameter d2 (hollow diameter) of the blades 168a and 168b of the second stirring and conveying screw 168 according to Example 4 is changed. In Example 4, when the outer diameter D1 of the blades 168a and 168b is 14 mm, the paddle interval is 180 °, and the paddle width H is 4 mm, the hollow diameter is changed in the range of 2 mm (φ2) to 10 mm (φ10). The experiment was conducted.

  As is clear from FIG. 12, in the case of the second stirring and conveying screw 168 having an outer diameter D1 of 14 mm, it was found that the hollow diameter of φ4 to φ8 is suitable for increasing the stirring rate while suppressing a decrease in the conveying speed. . Therefore, when the second stirring and conveying screw 168 is expressed by an inner diameter ratio to the outer diameter, the inner diameter is preferably 28% to 58% with respect to the outer diameter in order to balance the conveying speed and the stirring rate with good balance. The second stirring and conveying screw 158 described in the first embodiment also has the same result as the experimental result of the fourth embodiment only with no paddle. Therefore, the inner diameter is preferably 28% to 58% with respect to the outer diameter in order to achieve both the transfer speed and the stirring rate in a well-balanced manner, also for the second stirring and transporting screw 158 without paddles.

  As described above with reference to FIGS. 11 and 12, in the case of the second stirring and conveying screw 168 of the present embodiment having the paddle 170, the conveying speed and the stirring rate are selectively selected according to the arrangement interval and width of the paddle 170. It can be seen that it can be changed. In particular, by providing the paddle 170 as in this embodiment, the stirring rate can be improved while suppressing a decrease in developer transportability. However, the paddle 170 of the second agitating and conveying screw 168 has an effect of increasing the mechanical strength of the second agitating and conveying screw 168 in addition to such a function.

  The second agitating and conveying screws 158 and 168 are driven to rotate by a motor (not shown), but the second agitating and conveying screw 158 of the first embodiment that does not have a paddle has a diameter depending on the rotational driving and developer conveying load. There is a characteristic that the dimension of the direction is easy to change. That is, the blades 158a and 158b of the second stirring and conveying screw 158 are subjected to tension or compression stress depending on the rotational direction, and as a result, the diametrical dimension of the second stirring and conveying screw 158 is changed.

  Here, there is no particular problem if a sufficiently strong material such as a metal material is used as the second agitating / conveying screw 158, but when using a resin material to make it inexpensively, such a dimension in the diameter direction is used. There is concern that changes will occur. On the other hand, by arranging the paddle 170 so as to connect the blades 168a and 168b in the radial direction as in the second stirring and conveying screw 168 of the present embodiment, the above-described dimensional change in the diameter direction can be suppressed. it can.

[Another example of the second embodiment]
Next, another example of the second embodiment will be described using FIGS. 13 and 14. The basic configuration of the second agitating and conveying screws 168A and 168B shown below is the same as that of the second agitating and conveying screw 168 described in the second embodiment. Description will be omitted or simplified.

  The paddle 170 described in the second embodiment described above has advantages in terms of inexpensive manufacturing in addition to the above-described control elements for the conveyance speed and the stirring rate and the effect of suppressing dimensional change in the diameter direction. That is, in order to produce the part inexpensively in mass production, a molding technique is used which melts the material forming the part, and fills and cools the mold to obtain a finished shape.

  In this mold forming, it is important that there is no so-called undercut shape so that the mold can be divided easily. If there is a complicated undercut shape, molding is difficult, and parts are formed separately, which has disadvantages such as an increase in the number of parts, an increase in weight, and an increase in the number of assembling steps.

  Therefore, in the second stirring and conveying screw 168B of the present example, the paddle 170B as the first connection portion includes the plate-like portion 171 and the protrusion 172 projecting in the thickness direction on each of both sides of the plate-like portion 171 in the width direction. Have. The protrusion 172 is connected at a position where the pair of blades 168 a and 168 b are mutually offset in the rotation axis direction. In this example, by providing the projection 172 like this, even when the arrangement interval of the paddles 170 is 180 ° as in the second stirring and conveying screw 168 of the second embodiment, at the time of mold division by the paddles 170 Occurrence of undercut can be prevented.

  FIG. 13A is a diagram showing a division position when a mold for forming the second stirring and conveying screw 168A is divided in two directions (vertical direction in the drawing). Here, the center line PL is the mold division position, and the bidirectional arrow is the mold division direction. Here, as shown in FIG. 13B, when the joint portion between the paddle 170A and the blades 168a and 168b as the first connection portion of the second stirring and conveying screw 168A is enlarged, a minute undercut U in the mold division direction is generated. Occur. That is, when the blades 168a and 168b are connected to the paddle 170A at the same position in the rotation axis direction, an undercut U as shown in FIG. 13B occurs.

  It is also conceivable to slightly shift the position in the rotational axis direction of the connection portion of the blades 168a and 168b with respect to the paddle 170A so that such an undercut U does not occur. However, in this case, the shape of the connecting portion becomes complicated.

  For this reason, in the second stirring and conveying screw 168B of this example, as shown in FIGS. 14A and 14B, the projection 172 is provided on the surface of the paddle 170B at the connecting portion of the paddle 170B and the blades 168a and 168b. By doing so, the undercut is prevented. That is, by providing the protrusions 172, the blades 168a and 168b are simply abutted against the protrusions 172 without forming the connecting portions of the blades 168a and 168b in a complicated shape. Can be connected at mutually offset positions in the rotational axis direction. As a result, undercutting can be prevented with a simple configuration, and the second stirring and conveying screw 168B can be easily manufactured by mold division in two directions.

  In addition, in this example, as shown in FIG. 14 (b), the protrusion 172 has a substantially cylindrical shape. For example, the plate thickness of the plate-like portion 171 is 1 mm, the diameter of the protrusion 172 is 2 mm, and the protrusion 172 protrudes 0.5 mm on both sides in the thickness direction of the plate-like portion 171. However, the thickness of the plate-like portion 171 and the protruding amount of the protruding portion 172 in the thickness direction are not limited to this, but the protruding amount of the protruding portion 172 is preferably 1 mm or less on both sides in the thickness direction. In addition, the shape of the protrusion is not limited to a cylindrical shape as long as undercutting can be prevented, and the cross-sectional shape orthogonal to the longitudinal direction of the paddle 170B may be rectangular.

Third Embodiment
The third embodiment will be described using FIGS. 15 and 16 with reference to FIGS. 1 to 3. In the above-described second embodiment, the paddles 170 and 170B are formed in a plate shape, and are arranged so that the surface of the plate is substantially parallel to the rotation axis direction. On the other hand, in the present embodiment, the paddles 170C and 170D as the first connecting portion have the surface of the plate inclined with respect to the rotation axis direction. Since other configurations and operations are the same as those of the second embodiment, the same reference numerals are given to the same configurations as those of the second embodiment, and illustration and description thereof are omitted or simplified. The differences from the second embodiment will be mainly described.

  First, the second agitating and conveying screw 178 in FIG. 15 (a) forms a paddle 170C in a plate shape, and is entirely inclined with respect to the rotational axis direction. In such a configuration, the developer conveyed to the blade 168b is blocked by the paddle 170C more than the developer conveyed to the blade 168a. For this reason, although the stirring property of a developing agent can be improved, there exists a possibility that conveyance property may fall large.

  On the other hand, in the second stirring and conveying screw 178A of FIG. 15B, the paddle 170D has a first plate-like portion 173 and a second plate-like portion 174. The first plate-like portion 173 is a plate-like member which is inclined with respect to the rotation axis direction of the second stirring conveyance screw 178A and is connected to one of the pair of blades 168a and 168b. The second plate-like portion 174 is a plate-like member which is inclined in the direction opposite to the first plate-like portion 173 with respect to the rotation axis direction and is connected to the other blade 168 b. That is, the first plate-like portion 173 and the second plate-like portion 174 are disposed in a state of being mutually twisted around a line parallel to the radial direction passing through the connecting portion of the blade 168a or the blade 168b.

  Further, the first plate-like portion 173 and the second plate-like portion 174 have the same magnitude of the angle θ inclined with respect to the rotation axis, and are inclined in opposite directions to each other. For this reason, the 1st plate-shaped part 173 and the 2nd plate-shaped part 174 are arrange | positioned rotationally symmetrically with respect to the rotation center axis of the 2nd stirring conveyance screw 178A.

  Further, as shown in FIG. 15C, the first plate-like portion 173 and the second plate-like portion 174 make smooth the flow of the developer conveyed by the blades 168a or 168b to which the first plate-like portion 173 and the second plate-like portion 174 are respectively connected. The angle η of the blades 168a and 168b is set. That is, the first plate-like portion 173 is disposed such that the surface of the plate follows the surface of the blade 168a, and the second plate-like portion 174 is disposed such that the surface of the plate follows the surface of the blade 168b.

  In other words, as shown in FIG. 15C, it is assumed that the portion where the pair of blades 168a and 168b and the paddle 170D are connected is viewed from the radial direction. In this case, the angle な す formed by the first plate-like portion 173 and the one blade 168a and the angle η formed by the second plate-like portion 174 and the other blade 168b are less than 90 °. In particular, the angle η is preferably 45 ° or less, more preferably 30 ° or less.

[Experiment that investigated transport speed and agitation rate]
Here, in the case where the second stirring and conveying screw 178A of the second example of this embodiment is used (Example 5), and in Example 1 and Comparative Examples 1 to 3 described in the first embodiment, the developer FIG. 16 shows the experimental results of examining the conveyance speed and the stirring rate. In the experiment, Examples 1 and 5 and Comparative Examples 1 to 3 were placed in the stirring chamber of the developing device shown in FIGS. 2 and 3, and the conveyance speed and stirring rate in each case were examined. The experimental method is the same as the case where Example 1 and Comparative Examples 1 to 3 are described in the first embodiment.

  FIG. 16 is a diagram illustrating an angle θ inclined with respect to the rotation axis of the first plate-like portion 173 and the second plate-like portion 174 of the second stirring and conveying screw 178A according to the fifth embodiment in the range of 0 ° to 56 °. It is a graph of the relationship between the conveyance speed at the time of changing by, and experimenting, and a stirring rate. In Example 5, the paddle interval is 180 ° and the paddle width H is 4 mm at each angle θ.

  As is clear from FIG. 16, in the second agitating and conveying screw 178A, as the angle θ between the first plate-like portion 173 and the second plate-like portion 174 increases, the agitating performance decreases, and the conveying speed increases. I understand. In particular, it was found that when the angle θ is 5 ° to 56 °, the stirring rate can be significantly increased while suppressing a decrease in the conveyance speed with respect to Comparative Example 1.

  As described above, as in the first example, the paddle 170C is inclined in the rotation axis direction, and the first plate-like portion 173 and the second plate-like portion 174 are disposed so as to twist as in the second example. The speed and agitation rate can be controlled. In particular, by configuring as in the second example, it is possible to improve the stirring rate while suppressing a decrease in the conveyance speed.

Other Embodiments
In the above-described second and third embodiments, the paddles 170 and 170A to 170D are arranged at equal intervals, but for example, the vicinity of the point where the transfer characteristic is to be changed, such as the vicinity of the communication openings 156a and 156b shown in FIG. In this case, it is not always necessary to arrange them at regular intervals. For example, the distance between the paddles near the communication ports 156a and 156b may be larger than the distance between the paddles in the other regions.

  In the above-described embodiments, as the developing device, the configuration is described in which the developer is supplied to the developing sleeve 152 in the developing chamber 153a and the developer is recovered from the developing sleeve 152 in the developing chamber 153a. However, the present invention can also be applied to a so-called function separation type configuration in which the developer is supplied to the developing sleeve in the developing chamber and the developer is recovered from the developing sleeve in the stirring chamber.

  In each of the above-described embodiments, the present invention is applied to a multifunction machine having at least a plurality of functions of a copier, a printer, and a facsimile, but the present invention may be applied to another image forming apparatus such as a copier, a printer, and a facsimile. The present invention is also applicable.

  1 ... image forming device / 15 ... developing device / 100 ... image forming device main body / 151 ... developing container / 152 ... developing sleeve (developer carrier) / 153a ... developing chamber (First chamber) / 153b: stirring chamber (second chamber) / 157: first stirring conveyance screw / 158, 168, 168A, 168B, 178, 178A: second stirring conveyance screw (stirring conveyance (stirring conveyance Screws / 158a, 158b, 168a, 168b ... vanes / 158c ... connection portion (second connection portion) / 159 ... replenishment port / 170, 170A, 170B, 170C, 170D ... paddle (second 1 connecting portion) / 171 ... plate-like portion / 172 ... projection / 173 ... first plate-like portion / 174 ... second plate-like portion

Claims (16)

It is a stirring conveyance screw which conveys to a rotation axial direction, rotating and stirring developer,
Each of which is formed in a spiral shape along the rotational axis direction, and when viewed from the rotational axis direction, a plurality of blades arranged in a radial direction with a space between each other;
A connecting portion for connecting the multi-row blades at both ends in the rotation axis direction of the multi-row blades;
Stirring and conveying screw characterized in that. The multi-rowed vanes are equally spaced in the direction of rotation,
The stirring and conveying screw according to claim 1, wherein It is a stirring conveyance screw which conveys to a rotation axial direction, rotating and stirring developer,
Multi-row blades, each of which is helically formed along the rotation axis direction;
A first connecting portion that radially connects at least a pair of blades among the multi-row blades;
And a second connecting portion connecting the multi-row blades at both ends in the rotation axis direction of the multi-row blades;
The multi-rowed vanes are arranged radially with space therebetween when the portion excluding the first connection portion is viewed from the rotational axis direction.
Stirring and conveying screw characterized in that. The pair of blades are arranged at equal intervals in the rotation direction.
The stirring and conveying screw according to claim 3, wherein The plurality of first connection portions are arranged at equal intervals in the rotation axis direction,
The stirring conveyance screw according to claim 3 or 4 characterized by things. The pair of blades are arranged at the same pitch.
The stirring conveyance screw according to any one of claims 3 to 5, characterized in that. The length of the first connecting portion in the rotation axis direction is 5 to 15% of the pitch of the pair of blades.
The stirring and conveying screw according to claim 6, wherein The first connection portion is formed in a plate shape.
The stirring and conveying screw according to any one of claims 3 to 7, characterized in that The first connecting portion protrudes in the thickness direction at a part in the width direction of both sides of the plate-like portion and the plate-like portion, and the pair of blades are connected to each other at positions shifted in the rotation axis direction. Having
The stirring and conveying screw according to any one of claims 3 to 7, characterized in that The first connecting portion is inclined with respect to the rotation axis direction, and is connected to one of the pair of blades, and the first connection portion is connected to one of the blades and the rotation axis direction is the first connection portion. And one plate-like portion and a plate-like second plate-like portion inclined in the opposite direction and connected to the other blade,
The stirring and conveying screw according to any one of claims 3 to 7, characterized in that An angle formed between the first plate-like portion and the one blade when viewed from a radial direction at a portion where the pair of blades and the first connection portion are connected, and the second plate-like portion And the angle between the other blade is less than 90 °,
The stirring and conveying screw according to claim 10, wherein The multiple blades are arranged at the same pitch as one another.
The stirring conveyance screw according to any one of claims 1 to 11, characterized in that Each of the multi-blades has an inner diameter of 28 to 58% of an outer diameter when viewed in the rotation axis direction.
The stirring and conveying screw according to any one of claims 1 to 12, characterized in that: The multi-rowed blade is two rows,
The stirring and conveying screw according to any one of claims 1 to 13, characterized in that: A developer container containing a developer and having a first chamber, and a second chamber forming the circulation passage of the first chamber and the developer;
A developer carrier that carries and transports the developer in the first chamber;
The stirring and conveying screw according to any one of claims 1 to 14, wherein the developer is conveyed while being stirred in the second chamber.
A developing device. The second chamber has a supply port for supply developer.
The developing device according to claim 15, characterized in that:

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